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    • 专利摘要:
    PURPOSE: To provide a method for manufacturing an interlayer insulating film that cause no dishing in a CMP of a damascene wiring technique. CONSTITUTION: The method for manufacturing the interlayer insulating film for a multilayer wiring of a semiconductor integrated circuit includes a process of forming a 1st insulating film by a plasma CVD method using silicon-based hydrocarbon as material gas, and a process of forming a 2nd insulating film on the 1st insulating film by the plasma CVD method using silicon-based hydrocarbon gas and oxidative gas as material gas continuously in situ. Preferably, the flow rate of the oxidative gas is 1.2 to 100 times as large as the flow rate of the silicon-based hydrocarbon.
    公开号:KR20040023557A
    申请号:KR1020030063098
    申请日:2003-09-09
    公开日:2004-03-18
    发明作者:츠지나오토；오자키후미토시；타가하시사토시
    申请人:에이에스엠 저펜 가부시기가이샤；
    IPC主号:
    专利说明:

    Interlayer Insulation Film Used For Multilayer interconnect of Semiconductor Intergrated Circuit And Method Of Manufacturing The Same}
    [10] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer dielectric film used for multilayer interconnection of semiconductor integrated circuits and a method of manufacturing the same, and more particularly, to a polishing stop film used as a multilayer interconnection of Cu and a method of manufacturing the same.
    [11] Increasingly, miniaturization of integrated circuits is progressing toward the aim of more sophisticated and faster semiconductor integrated circuits. In the past, Al has been used as a multilayer interconnect material of semiconductor integrated circuits. However, as wiring becomes smaller and longer, problems of connection failure caused by electromigration resulting from increased current density and signal delay caused by Al's electrical resistivity and dielectric constant of the insulating film have become a problem.
    [12] It is Cu that attracts attention as the next-generation material to be used for multilayer interconnections. Cu has some problems with poor connection and has lower electrical resistance than Al. In 1997, a technology called Dual-Damascene was developed by IBM and Motorola. In the past, after the wiring was formed by convex etching of the Al film, the intermediate layer was filled with an insulating film. In contrast, in the dual-damacin interconnect technology, after electroplating / depositing Cu thin films on the entire surface by trench-etching a flat interlayer insulating film according to the interconnection pattern, the electroplating / deposited Cu is subjected to chemical mechanical polishing. Polishing by Chemical Mechanical Polishing (CMP) to form an interconnect with Cu remaining only within the trench portion (eg, "Next Generation ULSI Process Technology", Realize, Tokyo, February 29, 2000, page 558-565).
    [13] In this damascene interconnection technique, the adoption of an insulating film having a low dielectric constant is essential. As the low-k insulating film, an inorganic SOG film deposited by a spin coat process, an aC: F film deposited by a plasma CVD method using CxFyHz as a source gas, or a silicon-containing hydrocarbon as a source gas is used. SixCyOz films and the like deposited by plasma CVD methods are known.
    [14] In the CMP process of damascene interconnect technology, the surface of the wafer is polished using a polishing pad and polishing liquid (slurry mixture). If the mechanical strength of the insulating film is low, a problem arises called " dishing " in which the insulating film area is dug more than the Cu interconnect portion. When materials having different polishing rates are polished on the same polishing surface, materials having high polishing rates are caused to be unnecessarily polished because the polishing pad can deform. SixCyOz membranes, the most potent low-k membranes in damascene interconnect technology, contain many -CHx bonds and are porous to have low mechanical strength, resulting in dishing problems.
    [15] Providing a post-processing device to solve the dishing problem not only increases device space and cost, but also introduces particle contamination problems caused by wafer movement between devices.
    [16] In conclusion, it is an object of the present invention to provide a method for producing an interlayer insulating film in which dishing is effectively prevented during CMP of damascene interconnect technology.
    [17] Another object of the present invention is to provide a method for producing a low cost interlayer insulating film, which does not require a separate apparatus used to form the polishing stop layer.
    [1] Various aspects of the invention will be described with reference to the drawings showing the preferred embodiments attached thereto. However, this is only for illustrating the present invention, but is not necessarily limited thereto.
    [2] 1 is a schematic diagram illustrating a plasma CVD apparatus that may be used in a method of manufacturing an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit according to an embodiment of the present invention.
    [3] * Explanation of symbols for the main parts of the drawings
    [4] 1: plasma CVD apparatus 2: heater
    [5] 3: susceptor 4: semiconductor wafer
    [6] 5: source gas inlet port 6: reaction chamber
    [7] 7: 1st high frequency output source 8: 2nd high frequency output source
    [8] 9: shower head 10: outlet port
    [9] 11: grounding
    [18] Summary of the Invention
    [19] In one embodiment, the invention provides a method of forming an interlayer dielectric film for use in multilayer interconnection of a semiconductor integrated circuit, comprising: (i) a substrate by plasma CVD using a first source gas comprising a silicon-containing hydrocarbon gas; Forming a first insulating film on the substrate; (Ii) continuously forming a second insulating film on the first insulating film with a thickness less than or equal to the first insulating film in situ by plasma CVD using a second source gas containing a silicon-containing hydrocarbon gas and an oxidizing gas; ; (Iii) subjecting the second insulating film to polishing thereon for subsequent layer formation thereon; and providing a method for forming an interlayer insulating film. In the above embodiment, the first insulating film is 6 kV or less (including 1 kV, 2 kV, 3 kV, 4 kV, 5 kV, and any one of the above, preferably 1.5 to 2.5 kV). The second insulating film has a strength of about 6 kHz (6.5 ㎬, 7 ㎬, 8 ㎬, 9 ㎬, 10 ㎬, and a range including any of the above, preferably 6.0 to 7.0 ㎬). May have strength. The strength of the second insulating film can be achieved without any separate curing treatment. However, any suitable curing treatment to increase the mechanical strength, such as heating, electron beam, plasma annealing or the like, can be performed by any.
    [20] In another embodiment, the first source gas further includes an oxidizing gas having a flow rate of 1.0 times or less (preferably about 0.5 times) of the silicon-containing hydrocarbon gas. The first insulating film may be formed without oxidizing gas, and the silicon-containing hydrocarbon does not need to contain oxygen. When the silicon-containing hydrocarbon containing no oxygen is used, the first insulating layer may be a silicon carbide film. However, it is preferable that the first insulating film is a siloxane polymer or oligomer film having a high porosity because these films have a low dielectric constant.
    [21] In another embodiment, the oxidizing gas of the second source gas has a flow rate of at least 1.0 times that of the silicon-containing hydrocarbon gas. The second insulating layer includes more oxygen or Si—O bonds than the first insulating layer. The Si: O ratio is preferably about 1: 2. The second insulating film is formed using more oxygen in the source gas, resulting in a less porous structure.
    [22] In order to form less porous structure, the deposition rate can be reduced. For example, the second insulating layer may be formed under the condition that the RF output is reduced and the flow rate of the silicon-containing hydrocarbon is reduced compared to the first insulating layer. The flow rate of the silicon-containing hydrocarbon may be 50 to 300 sccm (including 75 sccm, 100 sccm, 150 sccm, 200 sccm, 250 sccm, and a range including any of the above). The oxidizing gas is 1 to 300 times (including 5, 10, 20, 30, 50, 80, 100, 150, 200 times, and the range including any of the above) of the silicon-containing hydrocarbon gas of one embodiment Can be used. In one embodiment, the oxidizing gas is selected from the group consisting of oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide and polyalcohol.
    [23] In another embodiment, the silicon-containing hydrocarbon of the second source gas is represented by the formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3, β Is an integer of 0 to 2, n is an integer of 1 to 3, and R is a C 1-6 hydrocarbon bonded to Si). The silicon-containing hydrocarbon is not limited thereto, and cyclic siloxane compounds may also be used. Preferred silicon-containing hydrocarbons may be dimethyl-dimethoxysilane. When the silicon-containing hydrocarbon gas of the first source gas and the silicon-containing hydrocarbon gas of the second source gas are the same gas, no additional piping for introducing the silicon-containing hydrocarbons of the different second source gas is necessary, thus making the process efficient. This can be done in situ.
    [24] In one embodiment, the second insulating film may be composed of multiple layers (eg, 2, 3, or 4 layers) containing different oxygen contents. The multilayer may be an oxygen-containing component or a plurality of layers or separation layers having gradients of Si—O bonds. For example, the farther the distance from the first insulating layer is, the more oxygen exists in the second insulating layer. The containing or Si-O bond can be high.
    [25] In one embodiment, the method comprises forming a plurality of via holes and / or trenches in the first and second insulating films, and forming holes and / or trenches with Cu for interconnection. The method further comprises the step of filling, wherein the polishing performed may be chemical mechanical polishing (CMP). In this embodiment, the second insulating film is effectively used as a polishing stop layer.
    [26] According to another aspect of the present invention, the present invention provides a method of forming an interlayer insulating film for use in multilayer interconnection of a semiconductor integrated circuit, comprising: (i) a first source gas comprising a silicon-containing hydrocarbon gas not containing oxidizing gas; Forming a first insulating film having a dielectric constant of 3.3 or less and an intensity of 6 kPa or less on the wiring layer of the substrate by plasma CVD using; (Ii) a dielectric constant of about 3.3 or less on a thickness of the first insulating film on the first insulating film in situ by plasma CVD using a silicon-containing hydrocarbon gas and a second source gas containing more oxidizing gas than the silicon-containing hydrocarbon; And continuously forming a second insulating film having a strength of about 6 GPa. In one embodiment, the method comprises forming a plurality of via holes and / or trenches in the first and second insulating films, filling holes and / or trenches with copper for interconnection, and The method may further include subjecting the insulating layer to chemical mechanical polishing (CMP).
    [27] According to still another aspect of the present invention, there is provided an interlayer insulating film for use in multilayer interconnection of a semiconductor integrated circuit, comprising: (a) a first insulating film formed by plasma CVD using a silicon-containing hydrocarbon as a source gas; b) a second insulating film formed on the first insulating film by plasma CVD using a silicon-containing hydrocarbon gas and an oxidizing gas as a source gas, the first insulating film having a dielectric constant of 3.3 or less (2.0, 2.5, 3.0, and A range in which any of the above is included, preferably 1.5 to 2.5, and a strength of 6 kPa or less (1 kPa, 2 kPa, 3 kPa, 4 kPa, 5 kPa, and any of the above, preferably Preferably, the second insulating film has a dielectric constant of about 3.3 (including 3.5, 4.0, 4.5, and any of the above, preferably 3.6 to 3.9) and has a strength of 6 ㎬ (6.5 ㎬, 7 ㎬, 8 ㎬, 9 ㎬ , An interlayer insulating film having a range of 10 GPa and any one of the above, preferably 6.0 to 7.0 GPa).
    [28] In one embodiment, the first insulating film is 0.1 to 10 μm (0.2 μm, 0.3 μm, 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 5.0 μm, and a range including any of the above, preferably May have a thickness of 0.3 to 2.0 μm, and the second insulating layer is 0.01 to 1.0 μm (0.02 μm, 0.03 μm, 0.05 μm) under the assumption that the second insulating layer is thinner than the first insulating layer. , 0.1 μm, 0.15 μm, 0.2 μm, 0.5 μm, and any one of the above, preferably from 0.03 to 0.15 μm). The second insulating film may be effectively employed as the polishing stop layer of the second insulating film, and the thickness is sufficient to achieve the above object.
    [29] To summarize the advantages and advantages of the prior art, certain objects and advantages of the invention have been described above. Of course, it will be understood that all of these objects and advantages need not be achieved in accordance with certain embodiments of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be implemented or practiced in a way that achieves or optimizes one advantage or advantage taught or implied herein without having to achieve the other objects or advantages taught or implied herein. You can do it.
    [30] Other aspects, aspects, and advantages of the invention will become apparent from the following detailed description of preferred embodiments.
    [31] Detailed description of the preferred embodiment
    [32] The invention will be described in detail below with reference to the preferred embodiments. However, the present invention is only intended to include these embodiments and should not be limited thereto.
    [33] In one embodiment, a method of forming an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit comprises the steps of: forming a first dielectric film by plasma CVD using a silicon-containing hydrocarbon gas as a source gas; Continuously forming a second insulating film on the first insulating film in situ by plasma CVD using a silicon-containing hydrocarbon gas and an oxidizing gas as a source gas after the first insulating film is formed; Subjecting the second insulating film to polishing thereon for formation of a subsequent layer thereon. The flow rate of the oxidizing gas is preferably 1.2 to 100 times that of the silicon-containing hydrocarbon gas.
    [34] In the present invention, one or more suitable silicon-containing hydrocarbon compounds may be used independently of the first insulating film and / or the second insulating film. Chain silicon-containing hydrocarbon compounds and / or cyclic silicon-containing hydrocarbon compounds may be used. Compounds that can be used include the formula Si α O α-1 R 2α-β + 2 (OR) β (where α is an integer of 1 to 3, β is 0, 1, 2, R is C 1-6 saturated hydrocarbon) Linear compounds having; A cyclic compound having the formula Si n O n R 2n , wherein n is an integer of 3 to 6 and R is a C 1-6 saturated hydrocarbon; At least one selected from the group consisting of cyclic compounds having the formula Si p (C 2 H 2 ) p R 2p (wherein p is an integer of 3 to 6, R is C 1-6 saturated or unsaturated hydrocarbon), It is not necessarily limited thereto.
    [35] The chain compound includes, but is not limited to:
    [36]
    [37]
    [38]
    [39] Wherein R 1, R 2, R 3, R 4, R 5, and R 6 are CH 3 , C 2 H 3 , C 2 H 5 , C 3 H 7 , C 6 H 5 , C 2 H 3 , C 3 H 5 , C 4 Each independently C 1-6 saturated or unsaturated hydrocarbon, such as H 7 , and C 4 H 5 .
    [40] Preferred linear silicon-containing hydrocarbon compounds have the formula:
    [41] Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β
    [42] Wherein α is an integer of 1 to 3, β is 0, 1, or 2, n is an integer of 1 to 3, and R is a C 1-6 hydrocarbon bonded to Si. In one embodiment, α is 1 or 2 and β is 2.
    [43] Source gases of this kind are disclosed in U.S. Patent No. 6,352,945, U.S. Patent No. 6,383,955, and U.S. Patent No. 6,432,846, all of which are incorporated herein by reference. In an embodiment, the source gas may be dimethyl-dimethoxysilane (DM-DMOS), 1,3-dimethoxytetramethyldisiloxane (DMOTMDS) or phenylmethyl dimethoxysilane (PM-DMOS). .
    [44] Cyclic compounds include, but are not limited to, the following compounds:
    [45]
    [46] Wherein R 1, R 2, R 3, R 4, R 5, and R 6 are CH 3 , C 2 H 3 , C 2 H 5 , C 3 H 7 , C 6 H 5 , C 3 H 5 , C 4 H 7 , and C Each independently C 1-6 saturated or unsaturated hydrocarbon, such as 4 H 5 .
    [47] Cyclic compounds having the formula Si p (C 2 H 2 ) p R 2p , wherein p is an integer from 3 to 6, R is a C 1-6 saturated or unsaturated hydrocarbon, include, but are not limited to: It is not:
    [48]
    [49] Wherein R 1, R 2, R 3, R 4, R 5, and R 6 are CH 3 , C 2 H 3 , C 2 H 5 , C 3 H 7 , C 6 H 5 , C 3 H 5 , C 4 H 7 , and C Each independently C 1-6 saturated or unsaturated hydrocarbon, such as 4 H 5 .
    [50] Different source gases may be mixed or one source gas may be used alone.
    [51] The first insulating film may be formed by any CVD method as long as it is appropriate. In one embodiment, the additive gas may be selected from the group consisting of a carrier gas, an oxidizing gas, and a plasma stabilizing gas. In order to form the first insulating layer, the oxidizing gas is in a range of 0 to 100% (10%, 20%, 30%, 40%, 50%, 80%, and any of the above) of the silicon-containing hydrocarbon compound, preferably Preferably 50% or less). The oxygen providing gas may be any gas as long as it can provide oxygen, which may include O 2 , NO, O 3 , H 2 O 2 , CO 2 , and N 2 O, thereby improving reaction efficiency at all times or Alternatively, the Si / O ratio (eg 1: 1.3 to 1: 1.7) in the reaction gas may be adjusted. For example, if the compound contains less than two alkoxy groups, oxidizing gas may be added to supply oxygen to form the siloxane polymer.
    [52] The carrier gas may be suitable as long as it is an inert gas including Ar, Ne, He, and N 2 . The inert gas may be supplied at a flow rate of 15 to 300% (50% or more in the embodiment) of the source gas. Furthermore, in one embodiment, CxHyOz (where x = 0.5, y = 2-12, and z = 0-0-3 (C n H 2n + 2 (n = 1-5), C n H 2n (n = 1-5), plasma stabilized (cross-linked) gas such as C n H 2n + 1 OH (n = 1 to 5), such as 1,2-propanediol and isopropyl alcohol, may be used to Can improve.
    [53] The flow rate of the additive gas may be 0% to approximately 500% (including 10%, 50%, 100%, 200%, 300%, 400%, and a range including any of the above) of the source gas flow rate. .
    [54] In one embodiment, the reaction gas is activated upstream of the reaction chamber. In this embodiment, the reaction gas can be activated in a remote plasma chamber installed upstream of the reactor, and the film is deposited on a substrate in the reactor. In this case, the reaction space consists of an interior of the remote plasma chamber, an interior of the reactor, and an interior of piping connecting the remote plasma chamber and the reactor. By using the interior of the remote plasma chamber, the interior of the reactor can be significantly reduced, thereby reducing the distance between the upper electrode and the lower electrode. This not only reduces the size of the reactor, but also makes it possible to uniformly control the plasma on the substrate surface. Any remote plasma chamber and operating conditions can be employed in the present invention as long as it is appropriate. See, for example, U.S. Patent Application, filed February 24, 2000. U.S. Patent Application No. 09 / 511,934, filed Jan. 18, 2001. Application 09 / 764,523, U.S. Patent 5,788,778 and U.S. The devices and conditions disclosed in patent 5,788,799 can be used. The contents disclosed in each of the above documents are incorporated herein by reference in their entirety.
    [55] Further, activation of the reaction gas consists of activating the additive gas and contacting the activated additive gas with the source gas. Activation of the reaction gas can be accomplished in the reactor or upstream of the reactor. As described above, both the source gas and the additive gas can be activated in a remote plasma chamber. Alternatively, activation of the reaction gas may be accomplished by activating the additive gas in a remote plasma chamber to mix it with the source gas downstream of the remote plasma chamber. Alternatively, the reaction gas may be heated in a preheating chamber installed upstream of the reactor and activated in the reactor, wherein the film may be deposited on a substrate in the reactor. The source gas and the additive gas may be introduced into the preheating chamber. In this case, the reaction space is composed of the interior of the preheat chamber, the interior of the reactor, and the interior of the piping connecting the preheat chamber and the reactor. By using the interior of the preheating chamber, the interior of the reactor can be significantly reduced, thereby reducing the distance between the upper electrode and the lower electrode. This not only reduces the size of the reactor, but also makes it possible to uniformly control the plasma on the substrate surface. Any remote plasma chamber and operating conditions can be employed in the present invention as long as it is appropriate. For example, the devices and conditions disclosed in the above references can be used.
    [56] Further, activation of the reaction gas consists of activating the additive gas and contacting the activated additive gas with the source gas. In this embodiment, the additive gas is activated in a remote plasma chamber, and the source gas is heated in a preheating chamber in which the activated additive gas is in contact with the source gas, and the reaction gas is reacted with the film deposition reactor. Will flow into me. In this case, since only the additive gas is present in the remote plasma chamber, it can effectively prevent the deposition of unwanted particles on the substrate of the remote plasma chamber causing ignition or ignition failure. The source gas is mixed with the activated additive gas downstream of the remote plasma chamber.
    [57] The flow rate of the reaction gas is determined based on the intensity of the RF output, the pressure selected for the reaction, and the type of the source gas and the crosslinked gas. The reaction pressure is usually in the range of 1 to 10 Torr, preferably in the range of 3 to 7 Torr, in order to maintain a stable plasma. The reaction pressure is relatively high to prolong the residence time of the reaction gas. The total flow rate of the reaction gas is important for reducing the relative dielectric constant of the final film. In general, the longer the residence time, the smaller the dielectric constant. The flow rate of the source gas required for film formation depends on the area of the substrate on which the film is formed and the desired deposition rate. For example, when a film is to be formed on a substrate (r (radius) = 100 mm) at a deposition rate of 300 nm / min, at least 50 sccm of source gas (preferably 100 to 500 sccm, 150, 200, 250) sccm) must be included in the reaction gas. The temperature of the semiconductor wafer may be maintained at a temperature of, for example, 350 to 450 ° C.
    [58] In one embodiment, the radio frequency (RF) output is a high frequency output that does not include a low frequency output. In one embodiment, the high frequency RF output and the low frequency RF output may be superimposed to effectively reduce film stress. That is, a high frequency output having a frequency of 2 MHz or more (including 5, 10, 15, 20, 25, 30, 40, 50, 60, 70 MHz, and any of the above ranges), and 2 MHz or less Combinations of low frequency RF outputs with frequency may be used (the ratio of low frequency output to high frequency output is less than 50% including 40, 30, 20, 10, 5, 0%, and any of the above ranges. , Preferably 1 to 10%). The high frequency RF output may be applied at high power levels of 1.5 W / cm 2 or more (including 2.0, 2.25, 2.5, 2.75, 3.0, 3.25, 3.5 W / cm 2, and the range in which any of the above is included). This high power level can increase the deposition rate and mechanical strength of the final insulating film.
    [59] In order to form the siloxane polymer or oligomer with the first insulating film of the present invention, the residence time of the reaction gas can be controlled as disclosed in US Pat. No. 6,352,945, US Pat. No. 6,383,955, and US Pat. No. 6,432,846. The contents disclosed herein are incorporated herein by reference in their entirety. However, in the present invention, the residence time can be spread far more broadly than in the literature. In an embodiment, Rt may be at least 50 Hz (including 70, 90, 100, 150, 200, 250 Hz, and the range in which any of the above is included).
    [60] The first insulating layer may have a dielectric constant of 2.0 to 3.5, preferably 2.5 to 3.1, and an intensity of 1.0 to 6.0 GPa, preferably 1.5 to 2.5 GPa. The film thickness can be changed according to the semiconductor design, in embodiments, it may be in the range of 0.1 to 5.0 ㎛, preferably 0.3 to 2.0 ㎛.
    [61] The second insulating layer may be continuously formed in the reaction chamber. The silicon-containing hydrocarbon compound used in the first insulating film may be used in addition to or in place of one or more different silicon-containing hydrocarbon compounds used in the second insulating film. The flow rate of the silicon-containing hydrocarbon compound used in the second insulating film may be less than that of the silicon-containing hydrocarbon compound used in the first insulating film. For example, the flow rate used for the second formation may be 100%, 80%, 60%, 40%, or 20% or less of the first formation. In an embodiment, the flow rate of the silicon-containing hydrocarbon compound used for the second formation is 10 to 1,000 sccm, preferably 50 to 300 sccm.
    [62] The deposition method, reaction chamber, and deposition conditions used for forming the first film may be employed as is for forming the second film, except as described below, but are not necessarily required. In addition, the second film may be continuously formed in the same reaction chamber, but is not necessarily required.
    [63] In forming the second insulating film, oxidizing gas is essential to improve mechanical strength. The oxidizing gas used herein is used as part of the source gas, but not used as part of the additive gas. The oxidizing gas may be the same as or different from the oxidizing gas used to form the first insulating film. However, since the oxidizing gas is used as a part of the source gas, that is, the elements constituting the second insulating film itself, the oxidizing gas is oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide, ethylene glycol, At least one selected from the group consisting of alcohols such as 1,2 propanediol, and isopropyl alcohol (IPA), which may be selected from silicon-containing hydrocarbon compounds and Si- Contribute to the formation of O bonds.
    [64] In one embodiment, the flow rate of the oxidizing gas may be higher than that of the silicon-containing hydrocarbon compound. For example, the flow rate ratio of the oxidizing gas to the silicon-containing hydrocarbon compound is 1.0 to 300, preferably 1.2 to 100 (1.5, 2, 5, 10, 20, 30, 50, 80, and any one of the above Including the included range). The high flow rate of the oxidizing gas can contribute to the film structure with less Si—C bonds and less C—H bonds, thereby making it possible to form a more compact and stable structure. In one embodiment, a silicon oxide polymer or oligomer is formed.
    [65] Inert gases and other gases (such as plasma stabilizing gases) may be added in the range of 0-100% (including 10, 30, 50, 80%, and any of the above) of the silicon-containing hydrocarbon compound. .
    [66] The RF output or frequency may be the same or different than that used for the first formation. In general, high power increases the mechanical strength of the membrane. However, when oxidizing gas is used at a high flow rate, the plasma may become unstable. In this case, the RF output is reduced. For example, the high frequency RF output may be applied at high power levels of 0.1 or more and 3.0 W / cm 2 or less (including 0.2, 0.5, 1.0, 1.5, 2.0, 2.5 W / cm 2, and the range in which any of the above is included). . The RF output used to form the second film may be 100, 80, 50, or 30% or less of the RF output used to form the first film. Similar to the above first film formation, a combination of a high frequency RF output and a low frequency RF output may be used. Although a higher frequency RF output is generally preferred, the RF output may be appropriately changed depending on the flow rate of the oxidizing gas and the flow rate of the silicon-containing hydrocarbon compound.
    [67] The reaction pressure used to form the second film is usually 0.1 to 10 Torr, preferably 0.5 to 5 Torr (0.75, 1, 2, 3, and the above, in order to maintain a stable plasma even when the flow rate of the oxidizing gas is high. It is in the range (including any one of the range). The reaction pressure used to form the second film may be lower than the reaction pressure used to form the first film. If the reaction pressure is too low or too high, the film thickness uniformity will be impaired.
    [68] The second insulating film has a dielectric constant of 3.0 to 5.0, preferably 3.5 to 3.9, and has a strength of 6 GPa or more, preferably 6 to 15 GPa. The film thickness can be changed according to the semiconductor design, and in this embodiment, it can be in the range of 0.01 to 0.5 탆, preferably 0.03 to 0.15 탆.
    [69] In another embodiment of the present invention, the second insulating layer may not be uniform in the vertical direction. That is, in the embodiment, the second insulating film has a strength increase and decrease in the vertical direction. The outermost surface of the second insulating film may be the hardest, and the landmark surface with the first insulating film may have the same strength as the first insulating film. In one embodiment, the flow rate of the oxidizing gas (and / or the reaction pressure, the RF output and frequency, the flow rate of the silicone-containing hydrocarbon compound, etc.) is gradually increased at an arbitrary rate, so that the outermost surface of the second insulating film As a result, the oxygen concentration may be increased and the carbon concentration may be decreased. In one embodiment, the closer the distance to the outermost surface of the second insulating film is, the higher the mechanical strength is.
    [70] In another embodiment, the second insulating film is composed of multiple layers or films, each having a different strength, wherein the closer the distance to the outermost surface of the second insulating film is, the higher the mechanical strength is.
    [71] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The drawings only show examples, and the invention is not limited thereto.
    [72] 1 is a schematic diagram illustrating a plasma CVD apparatus that may be used in a method of manufacturing an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit according to an embodiment of the present invention.
    [73] The plasma CVD apparatus 1 includes a reaction chamber 6. The susceptor 3 in which the semiconductor wafer 4 is disposed is provided in the reaction chamber 6. The susceptor 3 is supported by the heater 2. The heater 2 causes the semiconductor wafer 4 to maintain a predetermined temperature (for example, 350 to 450 ° C). The susceptor 3 is also used as one of the electrodes used for plasma discharge and grounded through the reaction chamber 6. In the ceiling part inside the reaction chamber 6, a showerhead 9 is arranged in parallel to the susceptor 3. The shower head 9 has a plurality of fine holes in the lower part, through which the source gas jets to be described below are discharged toward the semiconductor wafer 4. A source gas inlet port 5 is provided at the center of the shower head 9, and the source gas is introduced into the shower head 9 through a gas line (not shown). The gas inlet port 5 is electrically insulated from the reaction chamber 6. The shower head 9 is also used as the other electrode of the plasma discharge and is connected to the first high frequency output source 7 and the second high frequency output source 8 through the gas inlet port 5. Due to this structure, a plasma reaction region is created around the semiconductor wafer 4. The outlet port 10 is provided in the lower part of the reaction chamber 6, and is connected with the external vacuum pump (not shown).
    [74] A method of manufacturing an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit according to an embodiment of the present invention is described below. A method of manufacturing an interlayer insulating film used for multilayer interconnection of a semiconductor integrated circuit according to an embodiment of the present invention includes forming a first insulating film by a plasma CVD method using a silicon-containing hydrocarbon as a source gas. Wherein the source gas is a general formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3, β is an integer of 0 to 2, n is 1 An integer of ˜3, and R is a silicon-containing hydrocarbon represented by C 1-6 hydrocarbon bonded to Si, preferably DM-DMOS. In addition, as a sub-source gas, CO 2 , an alcohol, a hydrocarbon including at least one unsaturated bond, or N 2 may be included. If it is necessary to control the Si / O ratio, O 2 or N 2 O can also be added as a sub-source gas. Furthermore, as the additive gas, an inert gas such as Ar and / or He may also be added thereto.
    [75] After the reaction chamber 6 is introduced by the external vacuum pump (not shown), the source gas is introduced into the reaction chamber 6 from the gas inlet port 5 through the shower head 9. Thereafter, a high frequency output for plasma activation is applied from the first high frequency output source 7 and the second high frequency output source 8 so that the plasma reaction region is formed around the semiconductor wafer 4. Here, the frequency of the first high frequency output source 7 is 2 MHz or more, and the second high frequency output source 8 superimposed thereon is 2 MHz or less. It is possible to selectively use only the first high frequency output source 7. The first insulating film containing the source gas atoms chemically decomposed by the plasma reaction and SixCyOz is deposited on the semiconductor wafer 4.
    [76] In addition, a method of manufacturing an interlayer insulating film used for multilayer interconnection of a semiconductor integrated circuit according to an embodiment of the present invention is performed on the first insulating film by a plasma CVD method using a silicon-containing hydrocarbon and an oxidizing gas as a source gas. Forming a second insulating film on the substrate. The plasma CVD method used for the second insulating film may be the same as or different from the plasma CVD method used for the first insulating film. Furthermore, in another embodiment, the second insulating layer may be formed inside another reaction chamber.
    [77] The silicon-containing hydrocarbon used as the source gas is a general formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3, β is 0 to 2 An integer, n is an integer of 1 to 3, and R is a silicon-containing hydrocarbon represented by C 1-6 hydrocarbon bonded to Si, preferably DM-DMOS. The oxidizing gas used as the source gas is composed of at least one of oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide, or alcohol. As will be described in detail below, in one embodiment, through a thorough research work, by controlling the flow rate of the oxidizing gas to, for example, 1.2 to 100 times the flow rate of the silicon-containing hydrocarbon, It has high mechanical strength and functions as a polishing stop film.
    [78] After forming the first insulating film, continuously and in situ source gas is introduced into the reaction chamber 6 from the gas inlet port 5. At this time, the flow rate of the oxidizing gas, for example, can be controlled to 1.2 to 100 times the flow rate of the silicon-containing hydrocarbon. Thereafter, a high frequency output for plasma activation is applied from the first high frequency output source 7 and the second high frequency output source 8 so that the plasma reaction region is formed around the semiconductor wafer 4. Here, the frequency of the first high frequency output source 7 is 2 MHz or more, and the second high frequency output source 8 superimposed thereon is 2 MHz or less. It is possible to selectively use only the first high frequency output source 7. A second insulating film containing source gas atoms chemically decomposed by the plasma reaction, and SiO 2 is deposited on the semiconductor wafer 4.
    [79] The characteristic of the first insulating film is that it has a low dielectric constant. This is because the Si—C bond in the main source gas (silicon containing hydrocarbon) is bonded to the film as it is, thereby lowering the density of the film. The first insulating film has a disadvantage of having low mechanical strength because it includes a plurality of -CHx bonds in the film and is porous. In view of this particular aspect, the inventors of the present invention have led to the invention of a method of forming the second insulating film having a high mechanical strength on the first insulating film to overcome the disadvantages of the first insulating film. The characteristic of the second insulating film is that it has a high mechanical strength. C is not bound to the membrane due to excessive supply of oxidizing gas, and therefore it is known that the membrane becomes dense.
    [80] Example
    [81] An experiment was conducted to evaluate the interlayer insulating film formed by the method of manufacturing the interlayer insulating film according to the present invention; The experimental results are described below. In the experiment, using the DM-DMOS as the main gas, the CMP test of the damascene structure in which the second insulating film alone evaluation and the first and second insulating films were combined was performed in each case.
    [82] The conditions used are as follows:
    [83] Plasma CVD System: Eagle-12 (manufactured by ASM Japan, Tokyo)
    [84] <Deposition Conditions of First Insulation Film>
    [85] Address: DM-DMOS200 sccm
    [86] Gas addition: He400 sccm
    [87] 1st RF output: 27.12 ㎒ 2.8 W / ㎠
    [88] <Deposition Conditions of Second Insulation Film>
    [89] Address: DM-DMOS100 sccm
    [90] Oxidation gas: O 2
    [91] 1st RF output: 27.12 MHz
    [92] Other deposition conditions of the second insulating film are as shown in Table 1 below.
    [93] O 2 flow rate (sccm)Flow rate ratioPressure (Pa)1st RF frequency (W / ㎠) One2,00020250One 21201.2250One 310,000100250One 42,00020100One 52,00020400One 62,000202500.5 72,000202501.5 800250One 9500.5250One
    [94] Under these conditions, the film thickness distribution, the reflective index, and the strength of the film were evaluated by depositing the second insulating film by 1 mu m. The evaluation results are shown in Table 2.
    [95] Film thickness distribution (±%)Reflection indexStrength One1.61.456.5 22.01.456.3 32.21.456.6 43.71.456.8 54.91.456.1 61.91.456.2 71.81.456.7 8Unmeasured1.422.14 9Unmeasured1.432.06
    [96] The strength of the CMP polishing stop layer is preferably 6 kPa or more. From the above experimental results, preferred deposition conditions of the second insulating film are the flow rate of oxidizing gas / address gas = 1.2 to 100; The pressure is 100 to 400 Pa; It was understood that the first RF high frequency output = 0.5 to 1.5 W / cm 2. As can be seen, the flow rate of oxygen has a great influence on the mechanical strength. That is, at a ratio of approximately 1 of (O 2 / DM-DMOS), the intensity changes rapidly. In addition, membranes 8 and 9 have dielectric constants 2.90 and 2.88, respectively.
    [97] The CMP tests performed are described below. The first insulating film of 1 mu m was formed using the above-mentioned system and deposition conditions. Thereafter, a 0.1 μm second insulating film was continuously formed in situ according to the deposition conditions shown in Table 1. After CMP on the prepared damascene structure, no dishing was found under all conditions shown in Table 1.
    [98] As shown above, in the CMP process of damascene interconnect technology, by using the method of manufacturing the interlayer insulating film used for the multilayer interconnection according to the embodiment of the present invention, the insulating film serving as the polishing stop layer is provided. It becomes possible. As a result, the dishing problem of the low-k insulating film and the SixCyOz film can be effectively solved.
    [99] In addition, by using the method of manufacturing the interlayer insulating film used for the multilayer interconnection according to the embodiment of the present invention, since the conventional plasma CVD apparatus is used as it is, no additional apparatus for post-treatment is required at all; Thus, the method does not increase device space and cost.
    [100] The invention includes, but is not limited to, the following examples:
    [101] 1) A method of forming an interlayer insulating film used for multilayer interconnection of a semiconductor integrated circuit, comprising: forming a first insulating film by a plasma CVD method using a silicon-containing hydrocarbon gas as a source gas; Forming the first insulating film in situ by plasma CVD using a silicon-containing hydrocarbon gas and an oxidizing gas as a source gas, and subsequently forming a second insulating film on the first insulating film.
    [102] 2) The method of item 1, wherein the flow rate of the oxidizing gas is 1.2 to 100 times the flow rate of the silicon-containing hydrocarbon gas.
    [103] 3) The method of item 1, wherein the silicon-containing hydrocarbon is a general formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3, β is An integer of 0 to 2, n is an integer of 1 to 3, and R is a C 1-6 hydrocarbon bonded to Si).
    [104] 4) The method of item 3, wherein the silicon-containing hydrocarbon is dimethyl-dimethoxysilane.
    [105] 5) The method of item 1, wherein the oxidizing gas is composed of at least one of oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide or alcohol.
    [106] 6) The interlayer insulating film used for the multilayer interconnection of a semiconductor integrated circuit includes a first insulating film formed by plasma CVD using a silicon-containing hydrocarbon as a source gas, and a plasma CVD using a silicon-containing hydrocarbon gas and an oxidizing gas as the source gas. And a second insulating film formed on the first insulating film.
    [107] 7) In the interlayer insulating film used for the multilayer interconnection of item 6, the flow rate of the oxidizing gas is 1.2 to 100 times that of the silicon-containing hydrocarbon gas.
    [108] 8) In the interlayer insulating film used for the multilayer interconnection of item 6, the silicon-containing hydrocarbon is represented by the general formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β , wherein α is 1 An integer of 3, β is an integer of 0 to 2, n is an integer of 1 to 3, and R is a C 1-6 hydrocarbon bonded to Si).
    [109] 9) The interlayer insulating film used for the multilayer interconnection of item 8, wherein the silicon-containing hydrocarbon is dimethyl-dimethoxysilane.
    [110] 10) The interlayer insulating film used for the multilayer interconnection of item 6, wherein the oxidizing gas is composed of at least one of oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide or alcohol.
    [111] Many modifications are possible based on the technical idea of the present invention by those skilled in the art to which the present invention pertains. Therefore, it should be clearly understood that the forms of the present invention are illustrative only and are not intended to limit the scope of the present invention.
    [112] As shown above, in the CMP process of damascene interconnect technology, by using the method of manufacturing the interlayer insulating film used for the multilayer interconnection according to the embodiment of the present invention, the insulating film serving as the polishing stop layer is provided. It becomes possible. As a result, the dishing problem of the low-k insulating film and the SixCyOz film can be effectively solved.
    [113] In addition, by using the method of manufacturing the interlayer insulating film used for the multilayer interconnection according to the embodiment of the present invention, since the conventional plasma CVD apparatus is used as it is, no additional apparatus for post-treatment is required at all; Thus, the method does not increase device space and cost.
    权利要求:
    Claims (21)
    [1" claim-type="Currently amended] A method of forming an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit,
    Forming a first insulating film on the substrate by plasma CVD using a first source gas comprising a silicon-containing hydrocarbon gas;
    Continuously forming a second insulating film having a thickness less than or equal to the first insulating film on the first insulating film in situ by plasma CVD using a second source gas containing a silicon-containing hydrocarbon gas and an oxidizing gas;
    Subjecting the second insulating film to polishing thereon for subsequent layer formation thereon.
    [2" claim-type="Currently amended] The method of claim 1,
    And the first insulating film has a strength of about 6 GPa or less, and the second insulating film has a strength of about 6 GPa.
    [3" claim-type="Currently amended] The method of claim 1,
    And the first source gas further comprises an oxidizing gas having a flow rate of 1.0 times or less of the silicon-containing hydrocarbon gas.
    [4" claim-type="Currently amended] The method of claim 1,
    And the oxidizing gas of the second source gas has a flow rate of at least 1.0 times that of the silicon-containing hydrocarbon gas.
    [5" claim-type="Currently amended] The method of claim 4, wherein
    And the second insulating film is formed under a condition that the RF output is reduced and the flow rate of the silicon-containing hydrocarbon is reduced compared to the first insulating film.
    [6" claim-type="Currently amended] The method of claim 1,
    The silicon-containing hydrocarbon of the second source gas is represented by the formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3 and β is an integer of 0 to 2 , n is an integer of 1 to 3, and R is a C 1-6 hydrocarbon bonded to Si).
    [7" claim-type="Currently amended] The method of claim 6,
    The silicon-containing hydrocarbon is dimethyl-dimethoxysilane.
    [8" claim-type="Currently amended] The method of claim 1,
    The oxidizing gas is at least one selected from the group consisting of oxygen, dinitrogen oxide, ozone, hydrogen peroxide, carbon dioxide and polyalcohol.
    [9" claim-type="Currently amended] The method of claim 1,
    And the silicon-containing hydrocarbon gas of the first source gas is the same gas as the silicon-containing hydrocarbon gas of the second source gas.
    [10" claim-type="Currently amended] The method of claim 1,
    And the first source gas does not contain an oxidizing gas.
    [11" claim-type="Currently amended] The method of claim 1,
    And the second insulating film is composed of multiple layers containing different oxygen contents from each other.
    [12" claim-type="Currently amended] The method of claim 1,
    Forming a plurality of via holes and / or trenches in the first and second insulating films, and filling the holes and / or trenches with copper for interconnection;
    And then the polishing performed is chemical mechanical polishing (CMP).
    [13" claim-type="Currently amended] A method of forming an interlayer dielectric film used for multilayer interconnection of a semiconductor integrated circuit,
    Forming a first insulating film having a dielectric constant of 3.3 or less and an intensity of 6 kPa or less on the wiring layer of the substrate by plasma CVD using a first source gas containing a silicon-containing hydrocarbon gas that does not include oxidizing gas;
    A dielectric constant of 3.3 or less and a thickness of less than or equal to the first insulating film on the first insulating film in situ by plasma CVD using a second source gas containing a silicon-containing hydrocarbon gas and an oxidizing gas more than the silicon-containing hydrocarbon. And continuously forming a second insulating film having a degree of.
    [14" claim-type="Currently amended] The method of claim 13,
    Forming a plurality of via holes and / or trenches in the first and second insulating films, filling holes and / or trenches with copper for interconnection, and subjecting the second insulating film to chemical mechanical polishing (CMP). Further comprising the step of subjecting.
    [15" claim-type="Currently amended] In an interlayer insulating film used for multilayer interconnection of semiconductor integrated circuits,
    A first insulating film formed by plasma CVD using a silicon-containing hydrocarbon as a source gas,
    A second insulating film formed on the first insulating film by plasma CVD using a silicon-containing hydrocarbon gas and an oxidizing gas as a source gas,
    Wherein the first insulating film has a dielectric constant of 3.3 or less and has an intensity of 6 kPa or less, and the second insulating film has a dielectric constant of about 3.3 and has an intensity of about 6 mA.
    [16" claim-type="Currently amended] The method of claim 15,
    And the first insulating layer has a dielectric constant of 2.5 to 3.1 and an intensity of 1.5 to 2.5 GPa.
    [17" claim-type="Currently amended] The method of claim 15,
    And said second insulating film has a dielectric constant of 3.5 to 3.9 and a strength of 6 kW or less.
    [18" claim-type="Currently amended] The method of claim 15,
    The first insulating film has an interlayer insulating film, characterized in that 0.3 to 2.0㎛ thickness.
    [19" claim-type="Currently amended] The method of claim 15,
    The second insulating film has an interlayer insulating film, characterized in that having a thickness of 0.03 to 0.15㎛.
    [20" claim-type="Currently amended] The method of claim 15,
    The second insulating film is an interlayer insulating film, characterized in that the polishing stop layer.
    [21" claim-type="Currently amended] The method of claim 15,
    The silicon-containing hydrocarbon is a formula Si α O α-1 R 2α-β + 2 (OC n H 2n + 1 ) β (where α is an integer of 1 to 3, β is an integer of 0 to 2, n is 1 to An integer equal to 3 and R is a C 1-6 hydrocarbon bonded to Si).
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    同族专利:
    公开号 | 公开日
    US20040048490A1|2004-03-11|
    JP2004103752A|2004-04-02|
    JP4015510B2|2007-11-28|
    EP1396884A2|2004-03-10|
    EP1396884A3|2005-07-06|
    US7098129B2|2006-08-29|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2002-09-09|Priority to JP2002262304A
    2002-09-09|Priority to JPJP-P-2002-00262304
    2003-09-09|Application filed by 에이에스엠 저펜 가부시기가이샤
    2004-03-18|Publication of KR20040023557A
    优先权:
    申请号 | 申请日 | 专利标题
    JP2002262304A|JP4015510B2|2002-09-09|2002-09-09|Interlayer insulating film for multilayer wiring of semiconductor integrated circuit and manufacturing method thereof|
    JPJP-P-2002-00262304|2002-09-09|
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