• 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:
    A method for fabricating a semiconductor device comprising a chemical mechanical polishing step of the copper surface with a slurry containing H 2 O 2 as alumina particles, an oxidizing agent, The content of alumina particles at the time of polishing is 2 to 10% by weight based on the total amount of the slurry, and the concentration of H 2 O 2 is 8 to 26% by weight based on the liquid component in the slurry. Also advantageous and in a simple manner, there is provided a method of manufacturing a semiconductor device which can achieve flatness of the polishing surface of the metal film by CMP, that is, in-plane uniformity of polishing rate.
    公开号:KR19990073000A
    申请号:KR1019990006596
    申请日:1999-02-26
    公开日:1999-09-27
    发明作者:쓰치야야스아키；스즈키미에코
    申请人:가네꼬 히사시；닛본 덴기 가부시끼가이샤；
    IPC主号:
    专利说明:

    Semiconductor device manufacturing method {METHOD OF FORMING A SEMICONDUCTOR DEVICE}
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of planarizing a surface by chemical mechanical polishing of buried metal wiring, particularly copper wiring.
    Conventionally, in order to manufacture a semiconductor device, particularly a buried metal wiring, as shown in Figs. 4A to 4E, for example, an insulating film 102 is formed on a semiconductor substrate 101 having active elements (see Fig. 4A). A resist pattern 105 is formed on the insulating film 102, and the insulating film 102 is etched using a mask to form a contact hole 106 (see FIG. 4B). After forming the barrier film 103 such as Ti or Ta to fill the sidewall and bottom of the formed contact hole 106 (see FIG. 4C), the conductive material 104 is formed to fill the contact hole 106 ( 4d). Subsequently, the surface of the film is flattened by chemical mechanical polishing (hereinafter referred to as CMP) to form a buried interconnect (see FIG. 4E).
    In the CMP, the polishing slurry containing abrasive particles such as alumina or silica and an etchant such as hydrogen peroxide solution is supplied while the wafer fixed to the carrier is pressed against the rotating polishing plate attached with the polishing cloth.
    Conventionally, in the embedding process of wiring by CMP, various proposals have been made in the direction of this branch, which is largely classified into improvement of the composition of the abrasive used in CMP and improvement of the structure of the side to be polished.
    As for the composition of the abrasive, for example, as disclosed in Japanese Patent Application Laid-Open No. Hei 7-94455, an aqueous solution of hydrochloric acid, an aqueous solution of ammonium peroxide, an aqueous solution of chromium oxide, an aqueous solution of phosphate, an aqueous solution of ammonium hydroxide, ammonium chloride and ammonium hydroxide are used. A method of forming a wiring by CMP using an aqueous solution to be contained, an aqueous solution containing ammonium hydroxide and hydrogen peroxide or a mixture of the above aqueous solutions has been proposed. In this publication, by using the etchant as described above, the polishing rate ratio between the insulating film in which the wiring groove is formed and the metal film embedded as wiring in the groove can be increased, and as a result, the stopper effect of the insulating film at the time of polishing is improved. As a result, the polishing can be stopped at the time when polishing reaches the insulating film, and furthermore, the control of the metal film thickness is reliably achieved. In addition the publication, as an abrasive particle, and there were a mean particle diameter of the SiO 2 particles used in the below O.1㎛, SiO 2 particles as compared to Al 2 O 3 particles, the hardness is lower, and because the fine particles, It is described that the characteristics of the wiring are not damaged by polishing without damaging the surface of the relatively soft metal film containing copper.
    However, in this publication, due to the stopper effect of the insulating film, there is a problem that the central portion of the wiring is chemically etched and etched by the etchant, and thus cannot be said to be practical.
    In contrast, the present inventors first propose a method of improving the structure of the side to be polished rather than the composition of the abrasive and suppressing this chemical etching. This method is disclosed in Japanese Patent Laid-Open No. 9-148431. In other words, a conductive film is formed on the insulating film on which the through hole or the wiring forming groove is formed, and a protective film is formed on the conductive film, and the protective film and the conductive film are polished simultaneously by CMP to conduct the through hole or the wiring forming groove. A method of manufacturing a semiconductor device for filling a film is proposed.
    In Example 3 of this publication, first, a titanium / titanium nitride film is sputtered as a barrier film on the insulating film in which the via hole and the groove for forming the wiring are formed, and then copper wiring is formed by 1/1 of the minimum diameter of the via hole. At a thickness of 3, the first copper film having a thickness of 0.1 µm is formed as the first protective film, and the second copper wiring is formed up to 1/3 the thickness of the maximum width of the wiring forming groove. After the second titanium film was formed, the chemical polishing was performed using a polishing agent having a solid content concentration of 12% and a ratio of water and H 2 O 2 of 1: 1 by a chemical mechanical polishing method. The titanium film and the copper film of the second protective film of the part, the titanium film of the first protective film, the copper film, and the titanium nitride film and the titanium film of the barrier film are polished to fill the copper hole in the via hole and the wiring forming groove.
    Further, as the solid content of the alumina abrasive grain, one for range, the water and the ratio of H 2 O 2 of 5 to 33%: 0.1 to 1: in the range of 2 is described.
    The above method is extremely excellent as a method of suppressing chemical etching and preventing the occurrence of space in the via hole or the center of the wiring groove, but the step of forming a protective film on the conductive film is added, and the protective film thus formed is polished. Because of its elimination, there was room for improvement in economic terms.
    On the other hand, the wafer size to be polished is gradually increasing, and from 6 inches (about 15 cm) to 8 to 10 inches (about 20 to 25 cm) are becoming mainstream. In such an enlarged wafer, the uniformity of polishing in the in-plane direction becomes important. In other words, if the polishing is not sufficiently performed in the lyric part, the conductive film remains on the insulating film, causing problems such as leakage of wiring. In order to avoid this problem, if the polishing is sufficiently performed, the wiring is excessively changed in the corresponding portion, the height of the wiring is greatly changed, the wiring resistance is abnormal, and the EM (electromigration) resistance is deteriorated.
    Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device which is economically advantageous and can achieve a flatness of the polishing surface of the metal film by CMP, that is, in-plane uniformity of polishing rate, in a simple manner. have.
    1 is a graph showing the variation of the polishing rate with respect to the hydrogen peroxide concentration.
    2 is a graph showing a change in polishing rate with respect to hydrogen peroxide concentration.
    3 is a graph showing the variation of the polishing rate nonuniformity with respect to the alumina particle content.
    4A to 4B are schematic cross-sectional views illustrating a process of forming a copper buried wiring.
    ※ Explanation of symbols for main parts of drawing
    101 semiconductor substrate 102 insulating film
    103 barrier film 104 conductive material (copper film)
    105: resist pattern 106: contact hole
    107: CMP device
    MEANS TO SOLVE THE PROBLEM As a result of examining the composition of an abrasive | polishing agent in order to solve the said subject, as a result, even if it does not provide a protective film as mentioned above, by providing content in the grinding | polishing slurry of the alumina particle contained as abrasive grain in a predetermined | prescribed range, It was found that uniformity of high polishing rate was obtained.
    In other words, the present invention provides a method of manufacturing a semiconductor device having a chemical mechanical polishing process of a copper surface using alumina particles and a slurry containing H 2 O 2 as an oxidizing agent, wherein the content of alumina particles at the time of polishing is equal to the total amount of slurry. It is 2-10 weight% with respect to the manufacturing method of the semiconductor device.
    Further, in the production method of the present invention, the concentration of H 2 O 2 is 8 to 26% by weight based on the liquid component in the slurry.
    Conventionally, the commercially available alumina slurry for copper polishing has a solid content of about 3% by weight, and hydrogen peroxide solution is added thereto to prepare a CMP abrasive, and therefore less than 2% by weight in the softener. Usually, commercially available slurries contain an unknown component additive.
    In the present invention, it is completed by obtaining the knowledge that the uniformity of the polishing rate is improved by an extremely simple means of increasing the amount of alumina particles than conventionally used.
    On the other hand, in the above prior art, although alumina particles were increased from the viewpoint of simultaneously polishing a protective film such as titanium nitride, which is harder than copper, it is not described to improve the uniformity of the polishing rate, and is specifically defined in the present invention. It is not clear about the effect to be obtained to the extent.
    In the present invention, more remarkable effects can be obtained by defining the content of alumina particles and defining the concentration of hydrogen peroxide added as an etchant.
    In the present invention, the content of the alumina particles is in the range of 2 to 10% by weight based on the total weight of the polishing slurry, but is preferably 3 to 8% by weight.
    The amount of hydrogen peroxide added is in the range of 8 to 26% by weight, preferably 9 to 25.5% by weight, and optimally 10 to 20% by weight, based on the liquid component excluding the solid content in the polishing slurry.
    In preparing the polishing slurry used in the present invention, hydrogen peroxide is added to the alumina slurry prepared so that the alumina particles are in the above range in the state where hydrogen peroxide is finally added, and preferably, added immediately before polishing.
    The alumina slurry can be obtained by leaving a commercially available alumina slurry to settle the solid content and then removing the clear liquid of the upper layer so as to have a desired solid content concentration. At this time, although the additive of unknown component is included, the effect of this invention does not fall by presence of such an additive.
    For polishing, a substrate in which a copper film to be polished is formed may be provided in a conventionally known polishing apparatus, and the polishing pressure, the rotation speed, and the like may be adjusted to obtain a desired polishing rate. In the present invention, even within the range of polishing conditions usually carried out, even if the polishing rate is arbitrarily set, an extremely high polishing rate uniformity can be obtained in the in-plane direction of the polishing surface.
    The following experiment was conducted to examine the effect on the flatness due to the difference between the alumina concentration and the hydrogen peroxide concentration in the slurry.
    First, as a polishing sample, a SiO 2 film and a barrier film were formed on an S1 substrate, and copper was laminated thereon by a plating method with a thickness of 1.2 μm. Plating of copper is formed by depositing 100-200 nm copper by sputtering method after barrier film deposition, and performing plating. This sample was subjected to CMP by changing the composition of the polishing slurry, measuring the thickness of the copper layer before and after polishing, and evaluating the uniformity of the polishing rate in the in-plane direction.
    Polishing condition
    Polishing pressure: 3psi
    RPM: 25rpm
    The preparation of the abrasive is allowed to stand on the commercially available alumina slurry, to remove the clear liquid thereon, and to mix a slurry made with a desired alumina concentration with 35% hydrogen peroxide solution, to a predetermined alumina concentration (% by weight of the mixture as a whole) and a predetermined amount. The concentration of hydrogen peroxide (weight percent of the total liquid component except solids in the mixture) was adjusted to.
    In FIG. 1, the nonuniformity of the polishing rate (indicated by 3σ (%)) according to the difference in the hydrogen peroxide concentration at the alumina concentrations 2, 5 and 8% by weight is shown. When 3 sigma is 15% or less, since it can be practically used, hydrogen peroxide concentration is the range of 8-26 weight%, Preferably it is 9-25.5 weight%, The range of 10-20 weight% optimally It can be seen that.
    The result of measuring the change of the polishing rate on the same conditions is shown in FIG. As shown in Figure 2, it can be seen that the variation in the polishing rate with respect to the change in the hydrogen peroxide concentration is small.
    3 shows the nonuniformity of the polishing rate due to the difference in the alumina concentration when the human hydrogen peroxide concentration is set to 15% by weight. This figure shows that favorable results can be obtained when the alumina concentration is 2 to 10% by weight.
    According to the process shown in Fig. 4, a semiconductor device was formed. An insulating film 102 is formed on a semiconductor substrate 101 having active elements (see Fig. 4A), and a resist pattern 105 is formed on the insulating film 102, and the insulating film 102 is formed using this mask as a known method. Etching to form a contact hole 106 (see Fig. 4B). After forming the barrier film 103 such as Ti or Ta to fill the sidewall and bottom of the formed contact hole 106 (see FIG. 4C), the copper film 104 is formed by CVD to form the contact hole 106. Landfill (see FIG. 4D). Subsequently, the film surface is planarized by CMP to form a buried wiring (see FIG. 4E).
    In the CMP, hydrogen peroxide (34%) was added to the alumina slurry containing the alumina particles immediately before the polishing step, with 5% by weight of the alumina particles relative to the total slurry weight and hydrogen peroxide relative to the total amount of the liquid component in the slurry. A polishing slurry prepared to be 15% by weight was used.
    The EM resistance of the semiconductor device formed in this way was evaluated, and extremely good results can be obtained.
    As described above, in the present invention, when chemical mechanical polishing of a copper film is carried out using polishing slurry containing alumina particles as abrasive particles and hydrogen peroxide as an etchant, the content of alumina particles and the amount of hydrogen peroxide added are defined. By extremely simple operation, polishing with high in-plane uniformity of polishing rate that is unpredictable from the prior art is possible.
    权利要求:
    Claims (4)
    [1" claim-type="Currently amended] A method for fabricating a semiconductor device comprising a chemical mechanical polishing step of the copper surface with a slurry containing H 2 O 2 as alumina particles, an oxidizing agent,
    A method of manufacturing a semiconductor device, wherein the content of the alumina particles during polishing is 2 to 10% by weight based on the total amount of the slurry.
    [2" claim-type="Currently amended] The method of manufacturing a semiconductor device according to claim 1, wherein the concentration of H 2 O 2 is 8 to 26% by weight based on the liquid component in the slurry.
    [3" claim-type="Currently amended] The method of manufacturing a semiconductor device according to claim 1 or 2, wherein the slurry is mixed with alumina slurry and hydrogen peroxide immediately before being supplied to the chemical mechanical polishing process.
    [4" claim-type="Currently amended] The method of any one of claims 1 to 3, further comprising: forming an insulating film layer on a semiconductor substrate having active elements, etching the insulating film to form a contact hole, and forming a barrier to fill the sidewalls and bottom surfaces of the formed contact holes. A step of forming a film, a step of forming a copper film to fill said contact hole, and a step of planarizing the film surface by chemical mechanical polishing to form a buried wiring.
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    同族专利:
    公开号 | 公开日
    JP3147072B2|2001-03-19|
    CN1227404A|1999-09-01|
    US6235071B1|2001-05-22|
    TW425626B|2001-03-11|
    JPH11243071A|1999-09-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-02-26|Priority to JP04537398A
    1998-02-26|Priority to JP10-045373
    1999-02-26|Application filed by 가네꼬 히사시, 닛본 덴기 가부시끼가이샤
    1999-09-27|Publication of KR19990073000A
    优先权:
    申请号 | 申请日 | 专利标题
    JP04537398A|JP3147072B2|1998-02-26|1998-02-26|Method for manufacturing semiconductor device|
    JP10-045373|1998-02-26|
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