JP2007208010A - Process for fabrication of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily remove a photoresist film without degrading a porous organic siloxane film after the porous organic siloxane film is patterned with the photoresist film as a mask, in the process for fabrication of a semiconductor device using the porous organic siloxane film as an interlayer insulating film. <P>SOLUTION: A porous organic siloxane film is formed of which carbon content/silicon content is 0.3-0.7 while specific inductive capacity is 2.4-2.6, otherwise carbon content/silicon content is 0.4-0.6 while specific inductive capacity is 2.2-2.6. A photoresist film having a pattern is formed above it. With this as a mask, a porous organic siloxane film is dry-etched, and then the photoresist film is removed in aminic remover. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device using a low dielectric constant interlayer insulating film.

In recent years, it has been necessary to reduce the capacitance between wires from the viewpoint of high integration and high speed of a semiconductor device represented by a large scale integrated circuit (LSI). Therefore, a low dielectric constant having a relative dielectric constant lower than that of a conventional silicon oxide (SiO ₂ ) film (relative dielectric constant 3.9 to 4.2) as an interlayer insulating film such as an aluminum (Al) wiring or a copper (Cu) wiring. Studies for introducing membranes are being actively conducted.

Typical examples of the low dielectric constant film having a relative dielectric constant of 3 or less include an organic siloxane film, an inorganic siloxane film, and an aromatic organic polymer film. The organosiloxane film is mainly composed of silicon, oxygen, carbon, and hydrogen, and has a siloxane main skeleton and a methyl group (—CH ₃ ) that is a terminal group. Typical examples include a methylated siloxane (MSQ) film and a methylated hydrosiloxane (HMSQ) film. The inorganic siloxane film mainly contains silicon, oxygen, and hydrogen, and has a siloxane main skeleton and a hydrogen group (—H) that is a terminal group. A typical example is a hydrosiloxane (HSQ) film. The aromatic organic polymer film is mainly composed of carbon and hydrogen (which may contain a small amount of silicon or oxygen) and has a benzene ring skeleton. Typical examples are SiLK (product name) manufactured by Dow Chemical Company, CYCLOTENE (product name) manufactured by Dow Chemical Company, FLARE (product name) manufactured by Honeywell, and CRA (product name) manufactured by Sumitomo Bakelite.

  The relative dielectric constant of the low dielectric constant film is generally larger than 2.6, but a porous low dielectric constant film (relative dielectric constant 2) having a lower relative dielectric constant by introducing pores into these low dielectric constant films. .6 or less) is required. If a porous low dielectric constant film is used as an interlayer insulation film, the capacitance between wirings can be further reduced compared to the case of using a non-porous low dielectric constant film, and the semiconductor device is expected to be greatly integrated and increased in speed. it can. At present, porous organic siloxane films made from porous organic siloxane films are excellent in terms of moisture resistance stability, high mechanical strength, and low cost of materials. It is expected to be put to practical use.

  When forming contact holes and wiring grooves in the interlayer insulating film, it is necessary to process the interlayer insulating film using the photoresist film as a processing mask. Hereinafter, a conventional example in which a porous organosiloxane film is used as an interlayer insulating film will be described with reference to FIG.

  First, as shown in FIG. 1A, a porous organosiloxane film 102 is formed on a substrate 101 including semiconductor elements and wiring. The porous organosiloxane film 102 is generally formed using a coating method or a chemical vapor deposition (CVD) method. Next, a protective insulating film 103 made of, for example, a silicon oxide film is deposited on the organic siloxane film 102 using a CVD method. Subsequently, an antireflection film 104 and a photoresist film 105 are formed on the protective insulating film 103 by a coating method, and a hole pattern 106a is formed in the photoresist film 105 by using a known photolithography method.

  Using the photoresist film 105 having the hole pattern 106a thus formed as a mask, the antireflection film 104, the protective insulating film 103, and the porous organosiloxane film 102 are processed in this order as shown in FIG. . Thereby, the contact hole 106 b can be formed in the organosiloxane film 102. For such processing, dry etching using reactive plasma is widely used. As a gas for dry etching, a gas containing fluorine (F), for example, a fluorocarbon gas is mainly used.

  After the contact hole 106b is formed, it is necessary to remove the antireflection film 104 and the photoresist film 105 as shown in FIG. Usually, since the antireflection film 104 and the photoresist film 105 are hydrocarbon compounds composed of carbon and hydrogen, they can be easily removed by ashing with oxygen plasma (hereinafter, it is easy to remove the antireflection film and the photoresist film). This is called resist removal). However, in resist removal by oxygen plasma ashing, oxygen radicals and oxygen ions generated in the plasma also decompose organic components of the porous organosiloxane film. Such decomposition of the organic component causes film shrinkage and moisture absorption of the porous organosiloxane film and an increase in the relative dielectric constant. FIG. 1C shows a state in which the porous organic siloxane film 102 exposed on the side wall of the contact hole 106b has deteriorated and the side wall deterioration 111 has occurred. The side wall deterioration 111 leads to dimensional variation of the contact hole 106b, poor conduction, and an increase in inter-wiring capacitance.

  In order to suppress such deterioration of the organosiloxane film, a resist removal method that does not use oxygen plasma ashing has been studied.

For example, Patent Document 1 describes a method of performing resist removal using a non-oxidizing plasma gas. In this method, the resist is removed by plasma using a non-oxidizing gas, that is, a gas such as hydrogen (H ₂ ), ammonia (NH ₃ ), nitrogen (N ₂ ), or a mixed gas thereof. As described above, the use of hydrogen or nitrogen radicals or ions, which have a lower ability to decompose organic components than oxygen radicals or ions, can suppress degradation of the organic siloxane film to some extent. However, this method has a problem that the resist removal rate is slow and a resist residue is likely to be generated. In addition, when the organic siloxane film is made porous, radicals and ions easily penetrate into the porous chamber organic siloxane film. For this reason, the porous organic siloxane film undergoes non-negligible degradation even by non-oxidizing plasma. In addition, when a plasma containing nitrogen atoms such as nitrogen and ammonia is used, there is a problem that nitrogen atoms are taken into the organic siloxane film and the relative dielectric constant of the organic siloxane film is increased.

  On the other hand, a resist removal method in which the organosiloxane film is not exposed to the plasma for removing the resist has been studied.

  For example, Patent Document 2 describes a method for processing an organic siloxane film using a hard mask instead of a resist mask. In this method, a silicon carbide (SiC) film, a silicon nitride (SiN) film, or the like is formed on an organic siloxane film, and these films are processed into a hard mask by a resist mask and dry etching. Thereafter, the resist is removed by ordinary oxygen plasma ashing, and the organosiloxane film is processed by these hard mask and dry etching. At this time, since the organic siloxane film is not exposed to oxygen plasma, deterioration of the organic siloxane film can be suppressed. However, in this method, since the hard mask is etched to some extent under conditions for processing the organic siloxane film by dry etching, there is a problem that the shoulder of the processing pattern is likely to occur and the pattern size is likely to fluctuate.

  As another method of not exposing the organosiloxane film to plasma for resist removal, for example, Patent Documents 3 to 5 describe a resist removal method using a resist stripping solution. In these methods, an amine-based solution is used as a resist stripping solution, and an unnecessary photoresist film after dry etching is dissolved and removed. For this reason, it is possible to remove the resist without using oxygen, hydrogen, nitrogen plasma or the like that causes deterioration of the organic siloxane film. Moreover, since the resist stripping solution is also effective as a cleaning solution for removing a resist residue that is indispensable after dry etching, it can be expected that the manufacturing process is greatly simplified. Actually, this method is effective for a normal non-porous organic siloxane film, but there is a problem that the porous organic siloxane film is easily dissolved in an amine-based stripping solution. The alkaline amine-based solution hydrolyzes the siloxane bond (Si—O—Si), which is the main skeleton of the organic siloxane film, into silanol (Si—OH). As a result, the hydrophilicity of the organic siloxane film is increased, and at the same time, the denseness of the siloxane main skeleton constituting the film is lowered, so that the organic siloxane film is dissolved. In a porous organic siloxane film in which an organic siloxane film is made porous, the amine-based stripping solution easily enters the film, so that the dissolution in such an amine-based stripping solution becomes remarkable.

JP-A-2005-268312

JP 2005-38967 A JP 2000-352827 A JP 2003-35962 A JP 2005-49752 A

  As described above, conventionally, a porous organic siloxane film having a relative dielectric constant of 2.6 or less is required, but the porous organic siloxane film is not sufficiently resistant to an amine-based stripping solution, and can be used as an interlayer insulating film. It was difficult. In view of the above-described problems of the prior art, the present invention provides a porous organosiloxane film that is difficult to dissolve in an amine-based stripping solution, and a photoresist film in a semiconductor device manufacturing method using the porous organosiloxane film as an interlayer insulating film. It is an object of the present invention to provide a method for manufacturing a semiconductor device in which a photoresist film can be easily removed without dissolving a porous organic siloxane film after pattern processing using a mask as a mask.

  The above-mentioned problem is that a porous organic siloxane film whose dissolution rate is suppressed in an amine-based stripping solution is formed as an interlayer insulating film, a photoresist film having a pattern is formed thereon, and this is used as a mask to form a porous organic siloxane film. The problem is solved by processing the siloxane film by dry etching and removing the remaining photoresist film with an amine-based stripping solution.

  According to the study by the inventors, if the ratio of carbon element to silicon element in the porous organosiloxane film (hereinafter referred to as carbon amount / silicon amount) is small, the organic group which is a terminal group is reduced, so that the porous organic It has been found that the dissolution rate increases because the hydrophilicity of the siloxane film increases and the permeability of the amine-based stripping solution increases. On the other hand, when the amount of carbon / silicon is large, the organic group which is a terminal group of the porous organosiloxane film increases, so that the hydrophobicity increases, but the denseness of the siloxane main skeleton in the film relatively decreases. This has led to a decrease in the molecular weight of the molecules constituting the film, and it has also been found that the dissolution rate in the amine-based stripping solution is increased. Thus, if the carbon amount / silicon amount is too small or too large, the dissolution rate in the amine-based stripping solution becomes high, and the optimum range of carbon amount / silicon amount that keeps the dissolution rate in the amine-based stripping solution low. It has been clarified by investigations by the inventors. As a specific method for suppressing the dissolution rate of the porous organosiloxane film in the amine-based stripping solution, when the relative dielectric constant of the porous organosiloxane film is 2.4 or more and 2.6 or less, the carbon amount / silicon amount is set. When the relative dielectric constant is not less than 0.3 and not more than 0.7 and the relative dielectric constant is not less than 2.2 and not more than 2.6, the carbon amount / silicon amount is not less than 0.4 and not more than 0.6.

  According to the present invention, in a manufacturing process of a semiconductor device using a porous organic siloxane film as an interlayer insulating film, a photoresist can be easily formed with an amine stripping solution without eroding the patterned porous organic siloxane film. The film can be removed. Thereby, the variation in the pattern shape due to the porous organosiloxane film can be suppressed, and the performance variation of the semiconductor device can be suppressed. In addition, since the photoresist film can be easily removed, the manufacturing cost of the semiconductor device can be reduced. In addition, since the porous organic siloxane film is used as an interlayer insulating film, the capacitance between wirings can be reduced, and the speed and integration of the semiconductor device can be increased.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples and can be widely applied.

  In a normal semiconductor device manufacturing process, the processing time of the process using the amine-based stripping solution is about 10 minutes at the longest. Further, the dimensional variation of the interlayer insulating film due to various processes is required to be 10 nm or less. Accordingly, if the dissolution rate of the porous organic siloxane film in the amine-based stripping solution can be 1 nm / min or less, the porous organic siloxane film can be applied without any problem as an interlayer insulating film. Accordingly, porous organosiloxane films formed by a coating method with different relative dielectric constants and carbon / silicon contents were prepared, and the dissolution rate in amine-based stripping solution was examined.

  The raw material liquid for the porous organosiloxane film was applied onto an n-type silicon substrate having a resistivity of 0.001 Ωcm, and thermally cured at 400 ° C. for 30 minutes in a nitrogen atmosphere. The film thickness of the porous organosiloxane film after thermosetting was 200 ± 20 nm. The sample thus obtained was immersed in an amine-based stripping solution composed of a dimethyl sulfoxide solution containing 80% by weight of monoethanolamine at 70 ° C. for 10 minutes. The film thickness change of the porous organosiloxane film was measured before and after the treatment with the amine-based stripping solution, and the dissolution rate was calculated. An ellipsometer with a wavelength of 633 nm was used for measuring the thickness of the porous organosiloxane film. Moreover, the composition analysis by X-ray photoelectron spectroscopy (XPS) was used for the measurement of carbon amount / silicon amount. Moreover, the following method was used for the measurement of relative dielectric constant. That is, a circular aluminum electrode having a diameter of 3 mm was formed on the porous organosiloxane film formed on the n-type silicon substrate, and the electric capacity between the aluminum electrode and the n-type silicon substrate was measured at room temperature. At this time, the measurement frequency was 10 kHz. The relative dielectric constant was calculated using the obtained electric capacity, the thickness of the porous organosiloxane film, the area of the aluminum electrode, and the relative dielectric constant of vacuum.

  As a result of examining the dissolution rate of the porous organosiloxane film in the amine-based stripping solution by the above-described series of procedures, the result is as shown in FIG. In FIG. 2, the reason why the dissolution rate is increased when the amount of carbon / silicon in the porous siloxane film is too small is that the hydrophilicity of the film increases due to the decrease in the organic group which is the terminal group of the porous organic siloxane film. This is because the permeability of the system stripping solution into the film is increased. The reason why the dissolution rate is increased even if the amount of carbon / silicon in the porous siloxane film is too large is that the hydrophobicity of the film increases due to the increase in the organic groups that are the terminal groups of the porous organic siloxane film. On the other hand, the denseness of the siloxane main skeleton is relatively lowered. As can be seen from FIG. 2, the dissolution rate of the porous organic siloxane film having a relative dielectric constant of 2.4 or more and 2.6 or less in the amine-based stripping solution is such that the carbon amount / silicon amount is 0.3 or more and 0.7 or less. As a result, it was found that the thickness could be reduced to 1 nm / min or less. Further, it was found that when the relative dielectric constant is 2.2 or more and 2.6 or less, the dissolution rate can be reduced to 1 nm / min or less by setting the carbon amount / silicon amount to 0.4 to 0.6. Furthermore, it was also confirmed that there was no change in the relative dielectric constant of the porous organosiloxane film before and after the treatment with the amine-based stripping solution.

Next, the solubility of the photoresist film and the antireflection film in the amine-based stripping solution was examined. As a result, ghi mixed line resist, i-ray resist or KrF beam resist, ArF line resist, regardless of the type of photoresist such as a resist for _{F 2-wire,} also ghi mix line, for i-line, KrF line use, for ArF line was found to dissolve within 1 minute regardless of the type of anti-reflection film such as a F _2-wire.

  Based on the above knowledge, by controlling the carbon content / silicon content and film density of the porous organosiloxane film, a porous organosiloxane film having a dielectric constant of 2.2 to 2.6 and resistance to an amine-based stripping solution is prepared. it can. Here, the porous organic siloxane film may be a siloxane-based insulating film containing silicon, oxygen, carbon, and hydrogen, and is formed by a coating method or a CVD method. Heat treatment may be performed. Carbon in the porous organosiloxane film is present as an organic group, and the organic group is not particularly limited, such as an alkyl group, a vinyl group, or a phenyl group. From the viewpoint of adhesion of the porous organosiloxane film, the organic group is particularly preferably a methyl group. The amine stripping solution may be an organic solution or an aqueous solution containing 5% by weight or more of an amine component. As the amine component, ammonia, alkylamine, alkylrangeamine, hydroxylamine, alkanolamine, alkylhydroxylamine and the like can be used. The concentration of the amine component is preferably 5% by weight or more from the viewpoint of increasing the resist dissolution rate, particularly preferably 10% by weight or more, and further preferably 30% by weight or more. Resist removal with an amine-based stripper is performed at 10 to 90 ° C.

  By applying the present invention, a pattern using a porous organosiloxane film was formed. In this embodiment, the hole pattern forming process will be described as an example, but the same process can be used when forming a pattern other than the hole pattern (for example, groove pattern). Hereinafter, the pattern forming method will be described with reference to FIGS.

As shown in FIG. 3A, a porous organic siloxane film 202 having a thickness of 500 nm was formed on a substrate 201 by a plasma CVD method. Here, as the porous organic siloxane film 202, a methylated siloxane film having a carbon content / silicon content of 0.7 (relative dielectric constant 2.5) was used. After the application of the porous organosiloxane film 202, heat treatment was performed at 350 ° C. for 30 minutes in a nitrogen atmosphere. Further, a protective insulating film 203 made of a silicon oxide film having a thickness of 100 nm was deposited on the organosiloxane film 202 by a plasma CVD method. Here, as the protective insulating film 203, besides a silicon oxide (SiO ₂ ) film, a silicon oxynitride (SiON) film, a silicon carbide (SiC) film, a silicon carbonate (SiOC) film, and a silicon carbonitride (SiCN) film Etc. can be used. Further, an antireflection film 204 having a thickness of 60 nm and a photoresist film 205 having a thickness of 300 nm were formed by a coating method. Here, KrF-2MF1 manufactured by AZ was used as the antireflection film 204, and KRF-M89Y manufactured by JSR (both for KrF line) was used as the photoresist film 205. Subsequently, a hole pattern 206a having a diameter of 300 nm was formed in the photoresist film 205 by a known lithography method using a KrF line scanner.

Subsequently, as shown in FIG. 3B, the antireflection film 204, the protective insulating film 203, and the porous organic silicon film 202 are vertically processed by dry etching using reactive plasma, and the holes formed by the porous organic siloxane film 202 are processed. Pattern 206b was obtained. At this time, a mixed gas of CF ₄ and argon was used as a dry etching gas, and the plasma conditions were a pressure of 70 mTorr, an RF power of 500 W, and a temperature of 15 ° C. Here, for the dry etching of the porous organic siloxane film 202, any gas containing fluorine can be used. For example, in addition to a fluorocarbon gas such as CF ₄ , NF ₃ , SF _{6 and the} like can be used. In addition, in order to increase the dry etching speed and processing accuracy, an appropriate amount of oxygen, nitrogen, hydrogen, ammonia, helium, argon, or the like may be added to these gases.

  Next, as shown in FIG. 3C, the substrate having undergone the above-described steps was immersed in an amine-based stripping solution to remove the photoresist film 205 and the antireflection film 204. As the amine-based stripping solution, ACT-970 manufactured by Ashland (containing 5% by weight or more of hydroxylamine) was used, and the immersion condition was 50 ° C. for 10 minutes. The photoresist film 205 and the antireflection film 204 were completely dissolved and removed by the treatment with the amine stripping solution. Moreover, the side wall shape of the hole pattern 206b by the porous organosiloxane film 202 did not change before and after the treatment with the amine-based stripping solution.

  In the above example, the substrate is treated with an amine-based stripper immediately after the completion of dry etching to remove the photoresist film 205 and the antireflection film 204. However, depending on dry etching conditions, a hardened layer may be formed on the surface of the photoresist film, and the photoresist film 205 may be difficult to remove with an amine-based stripping solution. An example of removing the photoresist film 205 in such a case will be described below.

First, as shown above, the structure shown in FIG. Subsequently, as shown in FIG. 4A, the protective insulating film 203 and the porous organic silicon film 202 were vertically processed by dry etching using reactive plasma to obtain a hole pattern 206b of the porous organic siloxane film 202. At this time, a dry etching gas was a mixed gas of C ₄ F ₈ , nitrogen, and argon, and the plasma conditions were a pressure of 40 mTorr, an RF power of 1500 W, and a temperature of 15 ° C. As a result, a hardened layer 221 was formed on the surface of the photoresist film 205.

The photoresist film 205 and the antireflection film 204 could not be removed even when the substrate on which the cured layer 221 was thus formed was immersed in the above-described amine-based stripping solution. Therefore, as shown in FIG. 4B, immediately after the dry etching, the hardened layer 221 was removed by performing plasma surface treatment in the same plasma reaction chamber. CF ₄ was used as the plasma surface treatment gas, and the plasma conditions were 100 mTorr and 100 W. In the step of removing the hardened layer 221, there was no change in the side wall shape of the hole pattern 206b.

Subsequently, as shown in FIG. 4C, the photoresist film 205 and the antireflection film 204 were completely removed when immersed in the above-described amine-based stripping solution. At this time, the side wall shape of the hole pattern 206b by the porous organosiloxane film 202 did not change before and after the treatment with the amine-based stripping solution. Thus, after the dry etching of the porous organosiloxane film 202 is completed, the hardened layer 221 of the photoresist film can be removed by performing a surface treatment with a low-power reactive plasma for a short time. As the plasma surface treatment gas, fluorocarbon, NF ₃ , SF ₆ , oxygen, nitrogen, hydrogen, ammonia, or the like can be used, and fluorocarbon is preferable because the porous organic siloxane film hardly deteriorates. Among the fluorocarbons, CF ₄ is preferable because of its high removal rate of the resist cured layer. Moreover, it is preferable from the viewpoint of process simplification that such plasma surface treatment is performed in the same reaction chamber as that of dry etching.

  By applying the present invention, a wiring for a semiconductor device using a porous organosiloxane film was produced. Hereinafter, the manufacturing method will be described with reference to FIGS. Here, an example of manufacturing an aluminum wiring is shown, but the material of the wiring layer of the semiconductor device to which the present invention can be applied is not particularly limited. Or any of these alloy wirings. In addition, the types of semiconductor devices to which the present invention can be applied are not particularly limited, and include a wide variety of devices such as logic LSIs, large capacity memory LSIs, flat display devices such as liquid crystal TFTs, and MEMS elements.

  First, as shown in FIG. 5A, a laminated film of a titanium film, a titanium nitride film, and an aluminum alloy (containing 5 wt% copper) film was formed on a substrate 301 including semiconductor elements and wirings by a sputtering method. Thereafter, the laminated film made of the metal was processed into the wiring 311 by a known photolithography method and dry etching. The height of the wiring 311 is 250 nm, and the minimum wiring pitch is 300 nm.

  Subsequently, as shown in FIG. 5B, a porous organic siloxane film 302 having a thickness of 400 nm was formed by a coating method so as to cover the wiring 311. Here, as the porous organic siloxane film 302, a coating type methylated siloxane film having a carbon content / silicon content of 0.5 (relative dielectric constant 2.3) was used. After application of the porous organosiloxane film 302, heat treatment was performed at 400 ° C. for 30 minutes in a nitrogen atmosphere. Further, a protective insulating film 303 made of a silicon oxide film having a thickness of 100 nm was deposited on the porous organosiloxane film 302 by a plasma CVD method.

  Next, as shown in FIG. 5C, an antireflection film 304 with a thickness of 50 nm and a photoresist film 305 with a thickness of 250 nm were formed by a coating method. Here, ArF-2C manufactured by AZ was used as the antireflection film 304, and ZARF001F manufactured by ZEON (both for ArF lines) was used as the photoresist film 305. Subsequently, a hole pattern 306a having a diameter of 130 nm was formed in the photoresist film 305 by a known lithography method using an ArF line stepper.

Subsequently, as shown in FIG. 6A, the antireflection film 304, the protective insulating film 303, and the porous organic silicon film 302 are vertically processed by dry etching using reactive plasma, and contact with the porous organic siloxane film 302 is performed. Hole 306b was obtained. At this time, a mixed gas of CF ₄ , CHF ₃ , and argon was used as the dry etching gas, and the plasma conditions were a pressure of 100 mTorr, an RF power of 300 W, and a temperature of 15 ° C.

  Next, as shown in FIG. 6B, the photoresist film 305 and the antireflection film 304 were removed by immersing the substrate after the above-described steps in an amine-based stripping solution. As the amine-based stripping solution, EKC-265 manufactured by EKC Technologies (containing 5% by weight or more of organic amine) was used, and the immersion condition was 65 ° C. for 10 minutes. Thereafter, the substrate was immersed in isopropanol and rinsed. The photoresist film 305 and the antireflection film 304 were completely dissolved and removed by the treatment with the amine stripping solution. Further, by the treatment with the amine-based stripping solution, the dry etching residue on the wiring 311 exposed at the bottom of the contact hole 306b can be removed at the same time. Further, the shape of the side wall of the contact hole 306b formed by the porous organosiloxane film 302 did not change before and after the treatment with the amine-based stripping solution.

  Subsequently, as shown in FIG. 7A, a total of 300 nm of a laminated film composed of a titanium nitride film and a tungsten film was deposited by CVD, and an extra laminated film outside the contact hole 306b was removed by CMP. As a result, a contact plug 321 was formed. In the processing step using the amine-based stripping solution, the sidewall shape of the contact hole 306b was kept vertical, so that the film formation failure of the titanium nitride film and the tungsten film constituting the contact plug 321 did not occur. Here, when the substrate was heat-treated at 100 or more prior to the formation of the titanium nitride film and the tungsten film by the CVD method, the resistance of the contact plug 321 could be further reduced. This is because the organic solvent remaining in the porous organosiloxane film 302 is removed by evaporation or decomposition, and degassing during the formation of the titanium nitride film and the tungsten film is reduced.

  Finally, as shown in FIG. 7B, a laminated film of a titanium film, a titanium nitride film, and an aluminum alloy (containing 5 wt% copper) film was formed by a sputtering method. Thereafter, the laminated film made of the metal was processed into the wiring 312 by a known photolithography method and dry etching. The wiring 312 has a height of 400 nm and a minimum wiring pitch of 600 nm.

  In the two-layer aluminum alloy wiring formed in the above-described steps, the inter-wiring capacitance in the first-layer wiring 311 is measured, and is calculated from the relative dielectric constant 2.3 of the porous organosiloxane film 302. The same wiring capacitance as the value was obtained. This indicates that the porous organosiloxane film 302 did not deteriorate in the above-described process. In addition, it was confirmed that the resistance of the contact plug 321 connecting the wiring 311 and the wiring 312 was sufficiently low.

It is principal part sectional drawing explaining the pattern formation process by the conventional porous organosiloxane film. 2 is a graph showing the amount of carbon / silicon in a porous organosiloxane film in Example 1 and the dissolution rate in an amine-based stripping solution. It is principal part sectional drawing explaining the pattern formation process using the porous organosiloxane film in Example 2 (the 1). It is principal part sectional drawing explaining the pattern formation process using the porous organosiloxane film in Example 2 (the 2). FIG. 10 is a cross-sectional view (No. 1) of relevant parts for explaining a wiring manufacturing process using a porous organosiloxane film in Example 3. FIG. 10 is a principal cross-sectional view (part 2) illustrating a wiring manufacturing process using a porous organosiloxane film in Example 3. FIG. 10 is a cross-sectional view (No. 3) of relevant parts for explaining a wiring manufacturing process using a porous organosiloxane film in Example 3.

Explanation of symbols

101, 201, 301 ... substrate 102, 202, 302 ... porous organosiloxane film 103, 203, 303 ... protective insulating film 104, 204, 304 ... antireflection film 105, 205, 305 .. Photoresist films 106a, 106b, 206a, 206b, 306a ... hole pattern 306b ... contact hole 111 ... sidewall degradation 211 ... hardened layer 311, 312 ... wiring 321 ... contact plug .

Claims (16)

A method for manufacturing a semiconductor device comprising the following steps:
(A) A porous organic siloxane film having a carbon element to silicon element ratio of 0.3 to 0.7 and a relative dielectric constant of 2.4 to 2.6 is formed above the substrate. Process,
(B) forming a photoresist film having a pattern above the porous organosiloxane film;
(C) processing the porous organosiloxane film by dry etching using the photoresist film as a mask;
(D) A step of removing the remaining photoresist film with an amine stripping solution. In the manufacturing method of the semiconductor device according to claim 1,
The porous organosiloxane film contains at least silicon, oxygen, hydrogen, and carbon. In the manufacturing method of the semiconductor device according to claim 2,
The main organic group of the porous organosiloxane film is a methyl group. In the manufacturing method of the semiconductor device according to claim 1,
During the step (a), the porous organosiloxane film is formed by a coating method or a chemical vapor deposition method. In the manufacturing method of the semiconductor device according to claim 1,
The amine-based stripping solution is an aqueous solution or an organic solution and contains 5% by weight or more of an amine-based component. In the manufacturing method of the semiconductor device according to claim 1,
Between the step (c) and the step (d), the method further comprises a step of removing the hardened layer formed on the surface of the photoresist film in the step (c) by plasma treatment. In the manufacturing method of the semiconductor device according to claim 6,
The gas used for the plasma treatment is fluorocarbon. In the manufacturing method of the semiconductor device according to claim 1,
After the step (d), the method further includes a step of heat-treating the substrate at a temperature of 100 ° C. or higher. A method for manufacturing a semiconductor device comprising the following steps:
(A) A porous organosiloxane film having a carbon element to silicon element ratio of 0.4 to 0.6 and a relative dielectric constant of 2.2 to 2.6 is formed above the substrate. Process,
(B) forming a photoresist film having a pattern above the porous organosiloxane film;
(C) processing the porous organosiloxane film by dry etching using the photoresist film as a mask;
(D) A step of removing the remaining photoresist film with an amine stripping solution. In the manufacturing method of the semiconductor device according to claim 9,
The porous organosiloxane film contains at least silicon, oxygen, hydrogen, and carbon. In the manufacturing method of the semiconductor device according to claim 10,
The main organic group of the porous organosiloxane film is a methyl group. In the manufacturing method of the semiconductor device according to claim 9,
During the step (a), the porous organosiloxane film is formed by a coating method or a chemical vapor deposition method. In the manufacturing method of the semiconductor device according to claim 9,
The amine-based stripping solution is an aqueous solution or an organic solution and contains 5% by weight or more of an amine-based component. In the manufacturing method of the semiconductor device according to claim 9,
Between the step (c) and the step (d), the method further comprises a step of removing the hardened layer formed on the surface of the photoresist film in the step (c) by plasma treatment. In the manufacturing method of the semiconductor device according to claim 14,
The gas used for the plasma treatment is fluorocarbon. In the manufacturing method of the semiconductor device according to claim 9,
After the step (d), the method further includes a step of heat-treating the substrate at a temperature of 100 ° C. or higher.

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