• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    In a low pressure high density plasma processing chamber, a method is provided for stripping a photoresist mask used to etch a contact hole in a silicon layer of a substrate through an oxide layer and at the same time soft etching the surface of the silicon layer at the bottom of the contact hole. Simultaneous stripping and soft etching techniques are actually configured to remove the photoresist mask and at the same time reduce the contact resistance at the bottom of the contact hole. The method includes flowing an etchant source gas comprising carbon and O 2 into a plasma processing chamber before a contact hole is formed but fills the contact hole with the actual conductive material. The method also includes forming a plasma with an etchant source gas. Additionally, the method uses a plasma to simultaneously perform stripping and soft etching for a predetermined period of time sufficient to lower the contact resistance between the silicon substrate and the actual conductive material actually deposited into the contact hole to a predetermined acceptable level. Using steps.
    公开号:KR20010073107A
    申请号:KR1020017002802
    申请日:1999-08-31
    公开日:2001-07-31
    发明作者:티모씨 에벨；마티아스 페커
    申请人:로브그렌 리차드 에이치.；램 리서치 코포레이션；
    IPC主号:
    专利说明:

    TECHNIQUES FOR FORMING CONTACT HOLES THROUGH TO A SILICON LAYER OF A SUBSTRATE}
    [2] In the manufacture of semiconductor devices (eg integrated circuits or flat panel displays), contact holes such as trenches, biases, etc. may sometimes be formed in the silicon layer through the oxide layer of the substrate (eg silicon wafer or glass panel). Such contact holes can be etched in the plasma processing chamber, where plasma is used that can etch the oxide material through openings in the photoresist mask.
    [3] For ease of explanation, FIG. 1 shows a simplified layer stack including a silicon layer 102, an oxide (ie, a material comprising SiO 2 or SiO 2 ) 104 and a photoresist mask 106. stack) (100). For simplicity of explanation, only some exemplary layers are shown. However, as is well known, other layers (eg, including adhesive layers, bubble layers, antireflective layers, or other layers) may be disposed above, below, or between the layers shown. Silicon layer 102, in this embodiment, represents a single crystal silicon layer that may be disposed on a substrate or may mean the single crystal silicon layer itself. Exemplary opening 108 in photoresist mask 106 shows that the etch plasma can enter to remove material from oxide layer 104 to form a desired contact hole.
    [4] In FIG. 2, the contact hole 202 penetrates through the oxide layer 104 and is formed up to the lower interface between the oxide layer 104 and the silicon layer 102. As shown in FIG. Typically, the contact holes 202 are etched with a plasma that is formed using a fluorocarbon-based etchant source gas. In an exemplary manner, a suitable etchant source gas used to etch the contact holes through the oxide layer 104 may comprise CHF 3 or CHF 3 / C 4 F 8 . When activated, the fluorocarbon etchant source gas forms carbon species and fluoro species to etch oxide layer regions that are not protected by the photoresist mask 106. By adjusting the etching timing or providing an endpoint, the etching can be stopped near the interface between the oxide layer 104 and the silicon layer 102.
    [5] However, etching of the contact hole 202 has been found to leave a damaged area at the bottom of the contact hole 202. In an exemplary manner, the bottom of the contact hole 202 may have an amorphous silicon layer with C, H or F absorbed. In FIG. 2, such a damaged portion appears as a damaged area 204 at the bottom of the contact hole 202.
    [6] Unfortunately, the presence of damaged regions 204 results in increased contact resistance between the conductive material deposited into the contact holes 202 and the contact regions in the contact layer 102 (eg, doped wells). If the damaged area 204 is sufficiently thick, the contact resistance can become very large, resulting in a device defect.
    [7] In the prior art, the contact resistance due to the damaged area 204 can be reduced by removing a portion of the damaged area 204 in a separate etch process known as soft etch. Soft etch processing, which results in a separate etch step from the main contact etch used to etch through oxide layer 104, is typically performed using a gas mixture containing fluorocarbons.
    [8] After the soft etch another separation stripping step is used to remove the photoresist mask 106 as well as to remove the absorbed etch by-products formed on the inner surface of the plasma processing chamber during main contact etching. The stripping step typically uses O 2 as the main etchant source gas. Alternatively, some conventional processes perform a separation stripping operation before performing a soft etch. In high density plasma processing chambers (ie, chambers capable of producing plasma with an ion density of about 1013 ions / cm 3 or more), stripping and main contact etching operations are performed in the same plasma processing chamber to remove the photoresist mask. It is typical for the chamber to allow the main contact etch byproduct to be removed.
    [9] Three separation processing steps are required to etch the contact holes through the oxide layer (ie primary contact etching, soft etching and stripping operations) but these three separation steps have been found to be time consuming. . According to the prior art, the raw material throughput of the substrates through the plasma processing chamber is relatively low, which has the disadvantage of increasing the cost consumption of the etching tool. If these three separate processing steps are performed in other processing systems, additional costly facilities may be required, further increasing the cost of producing semiconductor principal component products.
    [10] In view of the foregoing, there is a need for improved techniques for forming contact holes directly in the silicon layer of a substrate in a plasma processing chamber.
    [1] The present invention relates to the manufacture of semiconductor devices. In particular, the present invention relates to an improved technique for forming a contact hole directly in a silicon processing layer of a substrate in a plasma processing chamber.
    [16] BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in a non-limiting embodiment manner, in which like elements in the accompanying drawings are designated by like reference numerals.
    [17] 1 is a cross-sectional view showing a simplified layer stack including a silicon layer, an oxide containing layer and a photoresist mask.
    [18] FIG. 2 is a cross-sectional view illustrating a contact layer formed through an oxide layer of the layer stack of FIG. 1.
    [19] 3 is a schematic diagram of a TCPTM 9100 plasma reactor showing a plasma processing chamber suitable for use with the present invention.
    [20] 4 is a block diagram illustrating the process steps involved in forming a contact hole in a silicon layer through an oxide layer in a low pressure high density plasma processing chamber in accordance with one embodiment of the present invention.
    [21] 5 is a cross-sectional view illustrating the application of the present invention to a stripping process comprising three substeps, according to another embodiment of the present invention.
    [11] The present invention, in one embodiment, relates to a method for etching a contact hole through an oxide layer of a substrate and into a silicon layer. The method includes providing a blank, including a layer of silicon, and placing the substrate in a plasma processing chamber. The method also includes performing a contact etch, which includes etching the contact holes through the oxide layer to the silicon layer. Contact etching uses a first plasma comprising carbon species and fluoro species. The method then includes simultaneously stripping a photoresist mask provided over the oxide layer for contact etching and soft etching the surface of the silicon layer at the bottom after contact. Such simultaneous stripping and soft etching causes an etchant source gas comprising fluorocarbons and O 2 to flow into the plasma processing chamber, forming a second plasma from the etchant source gas and simultaneously stripping and soft etching. By using a second plasma from the etchant source gas.
    [12] In another embodiment, the invention strips a photoresist mask used to etch a contact hole in a silicon layer through an oxide layer of a substrate in a low pressure, high density plasma processing chamber and at the bottom of the contact hole the surface of the silicon layer. The present invention relates to a method for simultaneously performing soft etching.
    [13] Simultaneous stripping and soft etching techniques are believed to substantially remove the photoresist mask and at the same time reduce the contact resistance at the bottom of the contact holes.
    [14] The method includes flowing an etchant source gas comprising fluorocarbon and O 2 into the plasma processing chamber after the contact hole is formed but before the contact hole is filled with the actual conductive material. The method also includes forming a plasma from the etchant source gas. Additionally, forming a plasma to simultaneously perform stripping and soft etching for a predetermined period of time sufficient to lower the contact resistance between the actual conductive material and the silicon substrate that is eventually deposited into the contact hole to a predetermined acceptable level. Included.
    [15] These and other advantages of the present invention will become apparent by reading the following detailed description and reviewing the various drawings.
    [22] The invention will be described in detail with reference to some preferred embodiments as shown in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without some or all of these feature descriptions. In other instances, well known process steps and / or structures have not been described in detail in order not to unnecessarily obscure the present invention.
    [23] In accordance with one embodiment of the present invention, an improved technique is provided to simplify the process of etching contact holes directly to the surface of a silicon layer of a semiconductor substrate. An improved contact hole formation technique is desirable to perform soft etching simultaneously in the damaged area at the bottom of the contact hole while removing the photoresist / absorbed etch byproducts. Thus, the removal and soft etching of the photoresist / absorbed etch byproducts that were conventionally performed in two separate process steps are combined into a single processing step to be performed in the same low pressure high density plasma processing chamber used for the main contact etch. As a result, the contact resistance at the bottom of the contact hole is reduced to the same time as the plasma processing chamber is cleaned, thereby reducing the number of three to two necessary steps.
    [24] In a non-obvious manner, the combined stripping and soft etching are performed simultaneously using a plasma formed with etchant source gas comprising a mixture of fluorocarbon and O 2 . In a typical case, the flow rate of the fluorocarbon gas used during the combined stripping and soft etching operations is less than the flow rate of the fluorocarbon gas used during the main contact etching operation. The use of etchant source gases comprising fluorocarbons and O 2 during the removal of photoresist / absorbed etch byproducts has been developed to remove carbon and fluoro main component byproducts as a result of main contact etching. In using an etchant source gas comprising a mixture of fluorocarbon and O 2 for stripping operations, the approach proposed here is an unexpected approach, where stripping is very specific (ie fluoro and carbon). It is proposed that the stripping process is designed to be eliminated. However, sufficient O 2 gas is provided to ensure that stripping of the photoresist / absorbed etch byproduct occurs during this step.
    [25] Moreover, the use of fluorocarbon gas during the stripping operation is unexpected, which means that the stripping operation always maximizes the removal of the photoresist / absorbed etch byproducts, while any incidentality of materials from the other layers of the layer stack. This is because it is made to minimize the removal of phosphorus. The use of a gas, such as a fluorocarbide principal component etchant source gas known to interfere with oxides and support single crystal silicon, is unexpected for designers of stripping processes. Nevertheless, as described below, using an etchant source gas comprising fluorocarbon gas and O 2 to simultaneously perform stripping and soft etching of photoresist / absorbed etch byproducts, The need for two tasks to be performed in two separate processing steps is eliminated.
    [26] It is anticipated that the improved contact hole forming technique of the present invention may be implemented in any suitable plasma processing system, where the system may be dry etched, plasma etch, reactive ion etch (RIE), magnetically enhanced reactive ion etch (MERIE). And the like suitable for the back. It penetrates through a capacitively coupled parallel electrode plate, through an electron cyclotron tuning (ECR) source, an ultrasonic plasma source, and inductively coupled RF such as a helicon, helical resonator, or induction coil (or planner). It doesn't really matter how energy is transmitted to the plasma through the circle. Among other things, ECR and TCP-brand (plasma coupled converter) plasma processing systems are available from Ram Research Corporation, Fremont, California.
    [27] In one embodiment, the present invention may be practiced in a TCP ™ 9100 low pressure high density plasma reactor, available from RAM Research Corporation, but any other conventional and suitable plasma processing system may be suitably used as described above. 3 shows a simplified schematic diagram of a TCP ™ 9100 plasma reactor 300 that includes a plasma processing chamber 302. An electrode 304 is arranged above the chamber 302, which is performed by an induction coil in the example of FIG. 3. Coil 304 is excited by RF generator 306 through a coupling network (not shown in FIG. 3). The RF power supplied to the coil 304 may have an RF frequency of 13,56 MHz, for example.
    [28] A gas distribution plate 308 is provided in the chamber 302, which distributes gaseous source material, such as, for example, etchant source gas, between the gas distribution plate itself and the substrate 310. And a plurality of holes for dispensing into the induced plasma region. The gaseous source material may also exit from the port formed in the brick of the chamber itself. Substrate 310 flows into chamber 302 and is disposed in chuck 312, which acts as a bottom electrode or for radiofrequency generator 314 (and typically through a matching network). ) Is preferably biased.
    [29] The RF energy supplied by the RF generator 314 may have an RF frequency of 4 MHz, for example, but other frequencies may be used. Chuck 312 may provide any suitable workpiece holder, and may be implemented, for example, as an electrostatic (ESC) chuck, mechanical chuck, vacuum chuck, or the like. The pressure in the chamber 302 during the plasma etch is preferably kept low, in one embodiment, between about 1 and 50 mTorr.
    [30] 4 shows the process steps involved in forming a contact hole through an oxide layer in a silicon layer in a low pressure high density plasma processing chamber, in accordance with one embodiment of the present invention. In step 404, main contact etching is performed in the silicon layer through the oxide layer. For etching through the oxide layer, a fluorocarbon etchant source gas may be used. As described above, the silicon layer may represent a silicon layer disposed on a substrate or may represent a silicon wafer itself.
    [31] Referring to the embodiment of FIG. 2, the contact hole 202 is formed after step 404 has been performed in the layer stack. In order to minimize the contact resistance at the bottom of the contact hole and at the same time to remove the photoresist / absorbed etch by-products, step 406 simultaneously performs soft etching and removal of the photoresist / absorbed etch by-products formed in step 404. .
    [32] In step 406, the combined soft etching and stripping process is performed using a plasma formed of an etchant source gas comprising fluorocarbon and O 2 . Fluorocarbon is preferably CF 4 , but may be provided as any suitable fluorocarbon or compound thereof (such as C 2 F 6 , C 4 F 8 , C 2 HF 5 , etc.). As mentioned above, the use of fluorocarbon gas (compound with O 2 ) during the stripping process is unexpected, which adds very constituent elements to the chamber that have been proposed to be stripped off for such use. Because it must. Moreover, the use of fluorocarbon principal component plasmas during the stripping process is unexpected, which is intended to minimize the removal of photoresist and absorbed etch byproducts and other materials during the stripping process when using fluorocarbon plasmas. Because it is against.
    [33] As noted in step 406, the combined soft etching and stripping steps are performed in the same low pressure high density plasma processing chamber in which the main contact etching step 404 is performed. In this way, the photoresist mask can be removed, the contact resistance at the bottom of the contact hole can be reduced, and the absorbed etching byproducts can be removed from the inner surface of the plasma processing chamber, all of which is one It can be done simultaneously in the combined stages of.
    [34] In the prior art there is a stripping process comprising three separation substeps. In this case, the present invention is also applicable and converts the conventional three secondary stage stripping process into a simultaneous stripping and soft etching process (also a process comprising three secondary stages) to separate soft etching process steps. Eliminate the need In accordance with one aspect of the present invention, a simultaneous stripping and soft etching process can be achieved by adding fluorocarbon gas to any one or multiple of the subsidiary steps of the three substage stripping process.
    [35] 5 shows how removal of photoresist / absorbed etch byproducts is performed in three separate substeps 502, 504, 406. Secondary step 502 is characterized by a relatively high pressure impact stage, where the force at the bottom of the low pressure high density plasma processing chamber increases the impact of the photoresist. In substep 504, the bottom force is released to separate the substrate from the chuck. However, the stripping continues because the plasma is continuously formed by the O 2 source gas. In an auxiliary step 506, the substrate is lifted onto the pins to physically separate the substrate from the chuck while stripping is continued using plasma in the plasma processing chamber.
    [36] In accordance with one aspect of the present invention, the addition of fluorocarbon gas (such as CF 4 ) may be added during any of the substeps 502, 504, 506 to achieve simultaneous soft etching. Fluorocarbon gas (eg, CF 4 ) is preferably added during the secondary step 506, where the stripping continues with the plasma while the substrate is separated from the chuck and supported by the fins. Physical separation of the substrate from the chuck increases the effectiveness of the soft etch and / or stripping process, since the substrate becomes hotter (without close contact with the chuck) to increase the soft etch rate and / or the stripping rate. It is believed to be.
    [37] Experimental Example
    [38] In one experimental example, a 6 inch single crystal silicon wafer with a photoresist mask (about 1.2 microns thick) disposed over an oxide layer is etched. Contact holes are etched through the oxide layer to the surface of the silicon substrate. The oxide layer itself is a multilayer film composed of a layer of doped or undoped oxides and having a thickness of about 1.5 to 2.1 microns. The contact hole to be formed has a contact opening of about 0.55 microns. A combined soft etch / stripping process is then performed to remove photoresist at the same time, remove etch by-products absorbed from the inner surface of the low pressure high density plasma processing chamber, and also reduce the contact resistance at the bottom of the contact hole.
    [39] The alternative parameters described below are suitable for the experimental etch in the TCP ™ 9100 plasma processing system described above. However, one of ordinary skill in the art will readily be able to apply these parameters to the implementation of the invention described above in other high density plasma processing chambers. The application of the variables described below to the need for other high density plasma processing chambers is within the skill of those skilled in the art familiar with plasma etching processes.
    [40] For main contact etching (eg, step 404 of FIG. 4), the pressure in the plasma processing chamber can be between about 2 to 50 mT, more preferably between about 3 to 15 mT, preferably about 5 mT. The TCP top power is between about 500 and 3,000 watts, more preferably between 800 and 2,500 watts, preferably about 1,700 watts. Bottom power is between about 300 and 1,250 watts, more preferably between about 600 and 1,250 watts, and more preferably about 1,100 watts. The flow rate of C 2 F 6 is between about zero and 100 sccm (standard cubic centimeters per minute), more preferably between about 5 and 50 sccm, with about 10 sccm being preferred. The flow rate of C 2 HF 5 is between about 0 to 100 sccm, more preferably about 20 to 100 sccm, and about 60 sccm is preferred. Although C 2 F 6 and C 2 HF 5 were used, it is contemplated that the main contact etching can be performed using any suitable fluorocarbon monogas or mixtures thereof. The main contact etch is allowed to continue for between about 30 seconds and about 300 seconds, more preferably between about 60 and 120 seconds, with about 90 seconds being preferred.
    [41] For high impact secondary stages of the stripping process (eg, secondary stage 502 of FIG. 5), the pressure may be between about 5 and 400 mT, more preferably between about 10 and about 20 mT, with about 15 mT being preferred. . The TCP (force) force is between about 300 and about 3,000 watts, more preferably between about 400 and about 2,000 watts, preferably about 1,000 watts. The lower force is a value less than the power setting of about 0 (zero) to the upper force setting, more preferably between about 100 and 300 watts, preferably about 200 watts. The flow rate of the 0 2 source gas is between about 100 and about 1,000 sccm, more preferably between about 200 and 700 sccm, and about 500 sccm is preferred. This high impact assisting step is allowed to continue for about 5 to 60 seconds, more preferably about 6 to 20 seconds, preferably about 15 seconds.
    [42] For the releasing and stripping secondary step (eg, secondary step 504 of FIG. 5) of the stripping process, the pressure may be between about 5 and 400 mT, more preferably between about 20 and 100 mT, and about 18 mT desirable. The TCP (force) force can be between about 300-3,000 watts, more preferably between about 400-2,000 watts, preferably about 1,000 watts. The floor force is preferably set to zero (zero) for this auxiliary step. The O 2 flow rate may be about 100 to 1,000 sccm, more preferably between about 200 to 700 sccm, and about 250 sccm is preferred. The releasing and stripping assist step of the chuck is allowed to continue for about 15 to 90 seconds, more preferably between about 15 to 30 seconds, and preferably about 20 seconds.
    [43] In the last auxiliary step of this experiment example, CF 4 is added to simultaneously perform soft etching and stripping of photoresist / absorbed etch byproducts. Although this is done, it is noted that the fluorocarbon gas can be added to any other auxiliary step or multiple auxiliary steps of the stripping process. In this last auxiliary step in which fluorocarbon gas is added, the pressure can be between about 5 and 400 mT, more preferably between about 10 and 20 mT, with about 18 mT being preferred. The TCP force may be between about 300 and 3,000 watts, more preferably between 400 and 2,000 watts, preferably about 1,000 watts. The floor force is preferably set to about zero (zero). The O 2 flow rate is preferably between about 100 and 1,000 sccm, more preferably between about 200 and 700 sccm, and preferably about 225 sccm. The CF 4 flow rate is between about 5 and 200 sccm, more preferably between about 5 and 50 sccm, with about 25 sccm being preferred. This auxiliary step is continued for about 15 to 300 seconds, more preferably between about 30 and 120 seconds, preferably about 60 seconds.
    [44] While the invention has been described with respect to several preferred embodiments, variations, substitutions, and equivalents thereof are within the scope of the invention. It is also noted that there are many alternative ways of implementing the methods and apparatus of the present invention. Therefore, the appended claims are to be construed as including all modifications, substitutions, and equivalents falling within the spirit and scope of the present invention.
    权利要求:
    Claims (24)
    [1" claim-type="Currently amended] A method for etching a contact hole in a silicon layer of a substrate through an oxide layer, the method being performed in a low pressure high density plasma processing chamber,
    Providing a substrate comprising the silicon layer;
    Placing the substrate in the plasma processing chamber;
    Performing contact etching, the step of etching the contact hole through the oxide layer in the silicon layer, the contact etching comprising contact etching comprising a first plasma comprising carbon species and fluoro species Performing step; And
    Stripping a photoresist mask provided to the oxide layer for the contact etching and simultaneously soft etching the surface of the silicon layer at the bottom of the contact hole, wherein the simultaneous stripping and soft etching is performed.
    Flowing an etchant source gas comprising fluorocarbon and O 2 into the plasma processing chamber,
    Forming a second plasma with the etchant source gas, and
    And a simultaneous stripping and soft etching step performed by using the second plasma from the etchant source gas for the simultaneous stripping and soft etching.
    [2" claim-type="Currently amended] The method of claim 1, wherein the fluorocarbon is CF 4 .
    [3" claim-type="Currently amended] The method of claim 1, wherein the plasma processing chamber is a conductively coupled plasma processing chamber.
    [4" claim-type="Currently amended] The method of claim 1, wherein the simultaneous stripping and soft etching steps are performed after the contact etching of all layers.
    [5" claim-type="Currently amended] The method of claim 1, wherein the layer is a single crystal silicon wafer.
    [6" claim-type="Currently amended] The method of claim 1, wherein the layer is a glass panel substrate shaped to form a flat panel display.
    [7" claim-type="Currently amended] The method of claim 1, wherein the simultaneous stripping and soft etching steps are performed for a predetermined period of time, the predetermined period of time being sufficient to lower the contact resistance between the subsequently deposited contact material and the silicon layer to a predetermined acceptable level. Way.
    [8" claim-type="Currently amended] The method of claim 1, wherein the simultaneous stripping and soft etching steps are performed while the bias force level of the plasma processing chamber is actually zero.
    [9" claim-type="Currently amended] The method of claim 1, wherein the simultaneous stripping and soft etching steps are performed while the layer is released from the chuck supporting the layer during the contact etching.
    [10" claim-type="Currently amended] A method for stripping a photoresist mask used for etching a contact hole in a silicon layer of a substrate through an oxide in a low pressure high density plasma processing chamber and simultaneously soft etching the surface of the silicon at the bottom of the contact hole. Simultaneous stripping and soft etching, wherein the photoresist mask is substantially removed and simultaneously the stripping and soft etching method reduces contact resistance at the bottom of the contact hole.
    Flowing an etchant source gas comprising fluorocarbon and O 2 into the plasma processing chamber after the contact hole is formed and before filling the contact hole with an actual conductive material;
    Forming a plasma with the etchant source gas; And
    Using the plasma for the simultaneous stripping and soft etching, wherein the simultaneous stripping and soft etching allows predetermined contact resistance between the silicon substrate and the actual conductive material deposited into the contact hole continuously. A method of simultaneous stripping and soft etching comprising a plasma use step performed for a predetermined period of time sufficient to lower as low as possible.
    [11" claim-type="Currently amended] The method of claim 10, wherein etching the contact hole prior to the simultaneous stripping and soft etching is performed with a plasma comprising carbon species and fluoro species.
    [12" claim-type="Currently amended] The method of claim 10, wherein the silicon layer is a single crystal silicon wafer.
    [13" claim-type="Currently amended] The method of claim 10, wherein the substrate is a glass panel shaped to form a flat panel display.
    [14" claim-type="Currently amended] The method of claim 10, wherein the fluorocarbon is CF 4 .
    [15" claim-type="Currently amended] The method of claim 10, wherein the plasma processing chamber is a conductively coupled plasma processing chamber.
    [16" claim-type="Currently amended] The method of claim 10, wherein the simultaneous stripping and soft etching steps are performed after the contact etching of all substrates.
    [17" claim-type="Currently amended] 11. The method of claim 10, wherein the simultaneous stripping and soft etching step is performed while the bias force level of the plasma processing chamber is actually zero.
    [18" claim-type="Currently amended] The method of claim 1, wherein the simultaneous stripping and soft etching steps are performed while the substrate is released from the chuck supporting the substrate during the contact etching.
    [19" claim-type="Currently amended] A method for etching contact holes in a single crystal silicon layer of a substrate through an oxide layer in a plasma processing chamber configured to produce a plasma having an ion density of about 1013 ions / cm 3 or more.
    Providing the substrate comprising the single crystal silicon layer;
    Placing the substrate in the plasma processing chamber;
    Performing a contact etch comprising etching the contact hole through the oxide layer to the single crystal silicon layer, wherein the contact etch comprises a first plasma comprising carbon species and fluoro species. Etching performing; And
    Stripping the absorbed by-products of the contact etch in the plasma processing chamber and simultaneously soft etching the surface of the single crystal silicon layer at the bottom of the contact hole, wherein the simultaneous stripping and soft etch is performed.
    Flowing an etchant source gas comprising fluorocarbon and O 2 into the plasma processing chamber,
    Forming a second plasma with the etchant source gas, and
    A simultaneous stripping and soft etching step performed by using the second plasma from the etchant source gas for the simultaneous stripping and soft etching,
    The simultaneous stripping and soft etching is performed in the same chamber used to perform the contact etching, wherein the simultaneous stripping and soft etching is performed before filling the contact hole with the actual conductive material. .
    [20" claim-type="Currently amended] The method of claim 19, wherein the fluorocarbon is CF 4 .
    [21" claim-type="Currently amended] 20. The method of claim 19, wherein the plasma processing chamber is a conductively coupled plasma processing chamber.
    [22" claim-type="Currently amended] 20. The method of claim 19, wherein the simultaneous stripping and soft etching steps are performed for a predetermined period of time, wherein the predetermined period of time is sufficient to lower the contact resistance between the subsequently deposited contact material and the single crystal silicon layer to a predetermined acceptable level. How to be.
    [23" claim-type="Currently amended] 20. The method of claim 19, wherein the simultaneous stripping and soft etching steps are performed while the bias force level of the plasma processing chamber is actually zero.
    [24" claim-type="Currently amended] 20. The method of claim 19, wherein the simultaneous stripping and soft etching steps are performed while the layer is released from the chuck supporting the layer during the contact etching.
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    同族专利:
    公开号 | 公开日
    KR100718072B1|2007-05-14|
    WO2000013230A1|2000-03-09|
    US6235640B1|2001-05-22|
    TW544801B|2003-08-01|
    JP2002524855A|2002-08-06|
    EP1118115A1|2001-07-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-09-01|Priority to US09/144,652
    1998-09-01|Priority to US09/144,652
    1999-08-31|Application filed by 로브그렌 리차드 에이치., 램 리서치 코포레이션
    2001-07-31|Publication of KR20010073107A
    2007-05-14|Application granted
    2007-05-14|Publication of KR100718072B1
    优先权:
    申请号 | 申请日 | 专利标题
    US09/144,652|US6235640B1|1998-09-01|1998-09-01|Techniques for forming contact holes through to a silicon layer of a substrate|
    US09/144,652|1998-09-01|
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