JP2007088003A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a substrate from being shaved through oxidization by allowing a silicon substrate not to be oxidized when removing a photosensitive resin used for pattern formation of an ion implantation area. <P>SOLUTION: This method includes a step wherein a transistor gate electrode 101 is formed in a semiconductor substrate 103, and an insulating film 104 is stacked on the semiconductor substrate; a step to form a pattern for an ion implantation area on the insulating film 104 by using a photosensitive resin 105, a step to form a pattern for the insulating film by using chemicals to remove the insulating film according to the pattern of the photosensitive resin; a step to use chemicals to remove the photosensitive resin on the pattern of the insulating film; and a step to conduct ion implantation on the semiconductor substrate where the photosensitive resin is removed. Thus, the photosensitive resin can be removed without using oxygen plasma, so that the oxidation of the substrate due to oxygen plasma and the quantity of shaving of substrate accompanied therewith can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a semiconductor device for suppressing oxidation of a silicon substrate with oxygen plasma when removing a resist used for pattern formation in an ion implantation region, and for suppressing the amount of chipping of the substrate caused by oxidation. Is.

  In a semiconductor device manufacturing method, an ion implantation process is an important process for forming a transistor. In performing ion implantation, in order to distinguish between regions that need to be implanted and regions that are not necessary, a pattern is formed using a resist, and the resist is removed after implantation (see, for example, Patent Document 1).

  Hereinafter, embodiments of the prior art will be described with reference to the drawings.

  FIG. 5 is a diagram showing a process for a method of manufacturing a semiconductor device according to an embodiment of the prior art. In FIG. 5, 901 is a gate electrode, 902 is a spacer, 903 is a silicon substrate, 904 is a photosensitive resin, 905 is an arsenic injection region, 906 is an injection hardened layer, 907 is an ashing oxide film, and 908 is a substrate shaving.

In the silicon substrate 903 on which the gate electrode 901 and the spacer 902 formed in a sidewall shape are formed on the gate electrode 901 (STEP 1), a pattern is formed on the silicon substrate 903 by using a photosensitive resin 904. (STEP2). Next, ion implantation is performed (STEP 3), and an arsenic implantation layer 905 is formed in a region where the silicon substrate 903 is exposed, and an implantation hardened layer 906 is formed on the surface of the photosensitive resin 904. For example, in the extension region implantation, arsenic is implanted at an acceleration voltage of 3 keV with an implantation amount of 1 × 10 15 atoms per square centimeter. The implantation depth at this time is on the order of several nm. On the other hand, an injection hardened layer 906 having a more crosslinked structure is formed on the surface of the photosensitive resin 904 by promoting polymerization between carbons, and this injection hardened layer 906 is not sufficiently dissolved and cannot be removed by washing with sulfuric acid. . Next, the photosensitive resin 904 is removed using oxygen plasma (STEP 4). At this time, since the silicon substrate 903 is exposed, the silicon substrate 903 is oxidized by oxygen plasma, and an ashing oxide film 907 is formed. For example, ashing is performed using a dry etching apparatus in which a microwave power source is connected to the upper part and an RF power source is connected to the lower part under conditions of an oxygen gas flow rate of 3000 sccm, a gas pressure of 10 Pa, a microwave power of 3000 W, and an RF power of 100 W. In the above ashing condition, an ashing oxide film of about 5 nm is formed. Next, a cleaning process is performed, the ashing oxide film is removed, and a substrate scraping 908 is formed (STEP 5). Generally, when silicon is oxidized to form a silicon oxide film, the volume is 2.2 times. Therefore, when the ashing oxide film is formed to 5 nm, the silicon film thickness used for the oxidation is 2.3 nm. That is, the silicon substrate 903 is cut by 2.3 nm. Further, when STEP 2 to STEP 4 are repeated, the silicon substrate 903 is further cut by 2.3 nm. Therefore, when a plurality of implantation steps are performed, the arsenic implantation layer 906 formed first disappears (STEP 6).
JP-A-61-231555 JP-A-11-162967 JP 2000-200246 A

  In recent years, with the miniaturization of semiconductor devices, the extension depth of the extension region has become increasingly shallow, and an implantation depth of about several nanometers is not uncommon. On the other hand, the silicon substrate is oxidized by oxygen plasma used when removing the resist. At this time, since a part of the silicon substrate is consumed by oxidation, when the silicon layer implanted in the previous process is used for oxidation, the implanted layer disappears in the implantation region.

  Accordingly, an object of the present invention is to solve the above-mentioned conventional problems, and when removing the photosensitive resin in which the ion-implanted region is patterned, the silicon substrate is not oxidized, thereby suppressing the abrasion of the substrate due to oxidation. A method for manufacturing a semiconductor device is provided.

  In order to achieve the above object, a method of manufacturing a semiconductor device according to claim 1 of the present invention includes a step of forming a gate electrode of a transistor on a semiconductor substrate, depositing an insulating film on the semiconductor substrate, and the insulating Patterning an ion implantation region using a photosensitive resin on the film; and forming a pattern of the insulating film by removing the insulating film using a chemical solution according to the pattern of the photosensitive resin; A step of removing the photosensitive resin on the insulating film pattern using a chemical solution; and a step of performing ion implantation on the semiconductor substrate from which the photosensitive resin has been removed.

  3. The method of manufacturing a semiconductor device according to claim 2, wherein a gate electrode of a transistor is formed on a semiconductor substrate, an insulating film is deposited on the semiconductor substrate, and a photosensitive resin is used on the insulating film. Patterning the implantation region; irradiating the semiconductor substrate on which the photosensitive resin pattern is formed with plasma of a mixed gas of fluorocarbon gas and oxygen; and irradiating the plasma with the photosensitive resin. Removing the region irradiated with the plasma in the insulating film using a chemical solution to form a pattern of the insulating film; and forming ions on the semiconductor substrate on which the insulating film pattern has been formed Performing the implantation.

  A method for manufacturing a semiconductor device according to claim 3 is the method for manufacturing a semiconductor device according to claim 1, wherein after the step of depositing the insulating film on the semiconductor substrate, a fluorocarbon gas and oxygen are formed on the insulating film. And a step of irradiating plasma of the mixed gas.

  A method for manufacturing a semiconductor device according to claim 4 is the method for manufacturing a semiconductor device according to claim 2 or 3, wherein the flow rate ratio of oxygen to fluorocarbon gas is 50 or more in the mixed gas of fluorocarbon gas and oxygen.

The semiconductor device manufacturing method according to claim 5 is the semiconductor device manufacturing method according to claim 2 or 3, wherein the fluorocarbon gas is CF ₄ , CHF ₃ , CH ₂ F ₂ , C ₂ F ₆ , or C ₃ F. ₈ , C ₄ F ₈ , C ₅ F ₈ , C ₄ F ₆ , or a combination of two or more.

  A method for manufacturing a semiconductor device according to claim 6 is the method for manufacturing a semiconductor device according to claim 2 or 3, wherein in the step of removing the insulating film, the chemical solution is hydrofluoric acid or ammonia perwater.

  The method of manufacturing a semiconductor device according to claim 7 is the method of manufacturing a semiconductor device according to claim 2 or 3, wherein the insulating film is a silicon oxide film, a silicon nitride film, a silicon carbide film, or another silicon compound. is there.

  9. The method of manufacturing a semiconductor device according to claim 8, wherein a gate electrode of a transistor and a first insulating film are formed on a side wall of the transistor on a semiconductor substrate, and a second insulating film different from the first insulating film is formed on the semiconductor substrate. A step of depositing an insulating film, a step of patterning an ion implantation region using a photosensitive resin on the second insulating film, and a chemical solution for the second insulating film according to the pattern of the photosensitive resin. Removing the photosensitive resin on the pattern of the second insulating film, removing the photosensitive resin on the pattern of the second insulating film using a chemical solution, and removing the photosensitive resin. Performing ion implantation on the semiconductor substrate.

  A method for manufacturing a semiconductor device according to claim 9 is the method for manufacturing a semiconductor device according to claim 8, wherein the selectivity between the first insulating film and the second insulating film in the chemical solution is 0.2. It is as follows.

  According to the method for manufacturing a semiconductor device of the first aspect of the present invention, the step of forming the insulating film pattern by removing the insulating film using a chemical solution according to the pattern of the photosensitive resin, and the pattern on the insulating film pattern Since the photosensitive resin is removed using a chemical solution, the photosensitive resin can be removed without using oxygen plasma. Therefore, it is possible to suppress substrate oxidation by oxygen plasma and the amount of substrate scraping associated therewith.

  According to the method for manufacturing a semiconductor device according to claim 2 of the present invention, the step of irradiating the semiconductor substrate on which the photosensitive resin pattern is formed with plasma of a mixed gas of fluorocarbon gas and oxygen, Since the step of removing the photosensitive resin and the step of removing the region of the insulating film irradiated with plasma using a chemical solution to form a pattern of the insulating film are performed, the ion implantation is performed without exposing the semiconductor substrate. The photosensitive resin in which the region is patterned can be removed using oxygen plasma. Therefore, it is possible to suppress substrate oxidation by oxygen plasma and the amount of substrate scraping associated therewith. In this case, the semiconductor substrate on which the photosensitive resin pattern is formed is irradiated with plasma of a mixed gas of fluorocarbon gas and oxygen, so that a selective ratio between a region exposed to the plasma and a region not exposed to the plasma is obtained. The area exposed to the plasma can be selectively removed.

  According to a third aspect of the present invention, as in the first aspect, the step of forming an insulating film pattern using a chemical solution according to the pattern of the photosensitive resin, and the step of removing the photosensitive resin on the insulating film pattern using the chemical solution. Therefore, the photosensitive resin can be removed without using oxygen plasma. Therefore, it is possible to suppress substrate oxidation by oxygen plasma and the amount of substrate scraping associated therewith. In this case, by irradiating the insulating film with plasma of a mixed gas of fluorocarbon gas and oxygen, the selectivity between the insulating film and the portion formed in a sidewall shape on the gate electrode is improved, and the insulating film is selected. Can be removed.

  According to the fourth aspect of the present invention, in the mixed gas of fluorocarbon gas and oxygen, the flow rate ratio of oxygen to fluorocarbon gas is 50 or more. Therefore, the ratio of the flow rate of fluorocarbon gas is increased, thereby preventing the insulating film from being etched.

According to claim 5, fluorocarbon _{gas, CF 4, CHF 3, CH} 2 F 2, C 2 F 6, C 3 F 8, C 4 F 8, C 5 F 8, one of C 4 _{F 6,} or 2 A combination of more than one type is preferred.

  According to the sixth aspect of the present invention, since the chemical solution is hydrofluoric acid or ammonia hydrogen peroxide in the step of removing the insulating film, a difference in etching amount between the insulating film not exposed to the plasma and the insulating film exposed to the plasma can be realized.

  Preferably, the insulating film is a silicon oxide film, a silicon nitride film, a silicon carbide film, or another silicon compound.

  According to the method for manufacturing a semiconductor device according to claim 8 of the present invention, the step of forming the pattern of the second insulating film by removing the second insulating film using a chemical solution according to the pattern of the photosensitive resin; Since the photosensitive resin on the pattern of the second insulating film is removed using a chemical solution, the photosensitive resin can be removed without using oxygen plasma. Therefore, it is possible to suppress substrate oxidation by oxygen plasma and the amount of substrate scraping associated therewith. In this case, since the second insulating film different from the first insulating film is deposited on the semiconductor substrate, the second insulating film and the first insulating film are formed when forming the pattern of the second insulating film. Thus, the second insulating film can be selectively removed.

  According to the ninth aspect, since the selection ratio of the first insulating film and the second insulating film in the chemical solution is 0.2 or less, the second insulating film can be selectively removed.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a diagram showing steps of a method for manufacturing a semiconductor device according to the first embodiment of the present invention. In FIG. 1, 101 is a gate electrode of a transistor, 102 is a spacer, 103 is a silicon substrate (semiconductor substrate), 104 is a plasma silicon oxide film (insulating film), 105 is a photosensitive resin, 107 is an arsenic injection layer, and 108 is an oxide. An arsenic implantation layer in the film.

  On the silicon substrate 103 on which the gate electrode 101 and the spacer 102 formed in a sidewall shape on the gate electrode 101 are formed (STEP 1), a plasma silicon oxide film 104 is deposited by using a plasma CVD method (STEP 2). At this time, the plasma CVD method is used, but another method may be used as long as the silicon substrate 103 is not oxidized. For example, the TEOS film may be deposited using a low pressure CVD method. Next, the region to be implanted is patterned using the photosensitive resin 105 (STEP 3), and the pattern is formed by wet etching the plasma silicon oxide film 104 according to the pattern of the photosensitive resin 105 (STEP 4). For example, hydrofluoric acid is used as the wet etchant, and the silicon oxide film is removed by processing in a chemical bath for 1 minute. Next, the photosensitive resin 105 is removed by washing with sulfuric water (STEP 5). At this time, since the photosensitive resin 105 is before ion implantation, a cured layer is not formed by implantation, and can be easily removed by washing with sulfuric acid. Therefore, since the photosensitive resin 105 can be removed without using oxygen plasma, the silicon substrate 103 is not oxidized by ashing.

  Next, ion implantation is performed (STEP 6). For example, in the extension region implantation, arsenic is implanted at an acceleration voltage of 3 keV with an implantation amount of 1 × 10 15 atoms per square centimeter. At this time, in the region where the silicon substrate 103 is exposed, arsenic is implanted into the silicon substrate 103 to form an arsenic implanted layer 107. On the other hand, in the region where the plasma silicon oxide film 104 remains, since the acceleration energy of ions is not so large, the arsenic ions stop in the middle of the plasma silicon oxide film 104 to form the arsenic implantation layer 108 and reach the silicon substrate 103. Not reach. That is, the remaining plasma silicon oxide film 104 functions as a mask for dividing the implantation region.

  Next, the remaining plasma silicon oxide film 104 is removed by a wet etching process using hydrofluoric acid or the like (STEP 7). However, it is not always necessary to remove the plasma silicon oxide film 104. If there is no problem in the next process, there is no problem even if the plasma silicon oxide film 104 is left without being removed.

  As described above, according to the first embodiment, since the photosensitive resin 105 can be removed by wet etching before implantation, it is not necessary to remove the photosensitive resin 105 using oxygen plasma. It is possible to provide a method for manufacturing a semiconductor device capable of suppressing the amount of shaving due to oxidation of the silicon substrate 103.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a diagram showing steps in the method for manufacturing a semiconductor device according to the second embodiment of the present invention. In FIG. 2, 101 is a transistor gate electrode, 102 is a spacer, 103 is a silicon substrate, 104 is a plasma silicon oxide film, 105 is a photosensitive resin, 106 is a plasma of a mixed gas of CF ₄ and oxygen, and 107 is an arsenic injection layer. , 108 are arsenic implanted layers in the oxide film.

On the silicon substrate 103 on which the gate electrode 101 and the spacer 102 formed in a sidewall shape on the gate electrode 101 are formed (STEP 1), a plasma silicon oxide film 104 is deposited by using a plasma CVD method (STEP 2). At this time, the plasma CVD method is used, but another method may be used as long as the silicon substrate 103 is not oxidized. For example, a silicon oxide film may be deposited by using a low pressure CVD method. Next, a region to be implanted is patterned on the plasma silicon oxide film 104 using a photosensitive resin 105 (STEP 3), and the surface of the patterned silicon substrate 103 is mixed with a mixed gas of CF ₄ and oxygen. Exposure to plasma 106 (STEP 4). For example, an oxygen gas flow rate of 500 sccm, a CF ₄ gas flow rate of 5 sccm, a gas pressure of 10 Pa, and a gas pressure of 10 Pa are applied to the upper induction coil in a dry etching apparatus comprising an induction coil at the top and an electrode connected to an RF power source at the bottom Plasma is generated under the condition that the power to be applied is 1000 W and the power to be applied to the lower electrode is 50 W, and the plasma treatment is performed for 2 minutes. At this time, CF ₄ gas was used, but either CHF ₃ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , or C ₄ F ₆ , or two types Other fluorocarbon gases such as the above combinations may be used. Further, since the plasma silicon oxide film 104 is etched when the ratio of the flow rate of the fluorocarbon gas is increased, the oxygen flow rate / fluorocarbon gas flow rate ratio is desirably 50 or more. Under the above conditions, the etching amount of the plasma silicon oxide film is 0.3 nm or less. At this time, the plasma silicon oxide film 104 has a region 104a exposed to plasma and a region 104b not exposed to plasma depending on the presence or absence of the photosensitive resin 105.

  Next, the photosensitive resin 105 is removed using oxygen plasma (STEP 5). For example, in an ashing apparatus using microwave plasma, the treatment is performed for 1 minute under the conditions of an oxygen flow rate of 5000 sccm, a gas pressure of 20 Pa, and a microwave power of 3000 W. At this time, since the silicon substrate 103 is covered with the plasma silicon oxide film 104, it is not exposed to oxygen plasma during ashing. Therefore, the silicon substrate 103 is not oxidized by ashing. Next, the plasma silicon oxide film 104a exposed to the plasma is removed by wet etching process (STEP 6). For example, as the wet etchant, hydrofluoric acid is used, and the silicon oxide film is removed by processing in a chemical bath for 1 minute. At this time, the plasma silicon oxide film 104 a exposed to the plasma 106 in STEP 4 is in a state in which some of the bonds in the silicon oxide film are cut by the plasma 106. Therefore, the etching amount of the plasma silicon oxide film 104b that has not been exposed to the plasma under the above-described wet etching conditions is 0.5 nm, whereas the etching amount of the plasma silicon oxide film 104a that has been exposed to the plasma is 4.5 nm. It becomes. Therefore, when the deposited film thickness of the plasma silicon oxide film 104 is 4.0 nm, the silicon oxide film 104a exposed to the plasma is removed by the wet etching process, but the silicon oxide film 104b not exposed to the plasma is Almost no etching is performed, and even if the etching amount (0.3 nm or less) at the time of the plasma 106 irradiation is taken into consideration, 3.3 nm remains.

  Next, ion implantation is performed (STEP 7). For example, in the extension region implantation, arsenic is implanted at an acceleration voltage of 3 keV with an implantation amount of 1 × 10 15 atoms per square centimeter. At this time, in the region where the silicon substrate 103 is exposed, arsenic is implanted into the silicon substrate 103 to form an arsenic implanted layer 107. On the other hand, in the region where the plasma silicon oxide film 104 b remains, since the acceleration energy of ions is not so large, the arsenic ions stop in the middle of the plasma silicon oxide film 104 b to form the arsenic implantation layer 108 and reach the silicon substrate 103. Not reach. That is, the remaining plasma silicon oxide film 104b functions as a mask for dividing the implantation region.

  Next, the remaining plasma silicon oxide film 104b is removed by a wet etching process using hydrofluoric acid or the like (STEP 8). However, it is not always necessary to remove the plasma silicon oxide film 104. If there is no problem in the next process, there is no problem even if the plasma silicon oxide film 104 is left without being removed.

  In the above-described embodiment, hydrofluoric acid is used as a chemical solution for removing the plasma silicon oxide film 104a exposed to plasma in STEP 6, but a chemical solution capable of realizing the same etching amount difference, for example, ammonia overwater, is used. I do not care. Further, although the film deposited by the plasma CVD method is the plasma silicon oxide film, it may be a plasma silicon nitride film or a plasma silicon carbide film.

As described above, according to the second embodiment, the photosensitive resin 105 can be removed using oxygen plasma without exposing the surface of the silicon substrate 103. Therefore, it is possible to provide a method for manufacturing a semiconductor device that can suppress oxidation of the silicon substrate 103 with oxygen plasma and suppress the amount of abrasion of the silicon substrate 103.
(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a diagram showing steps in the method for manufacturing a semiconductor device according to the third embodiment of the present invention. In FIG. 3, 101 is a transistor gate electrode, 102 is a spacer, 103 is a silicon substrate, 104 is a plasma silicon oxide film, 105 is a photosensitive resin, 106 is a plasma of a mixed gas of CF ₄ and oxygen, and 107 is an arsenic injection layer. , 108 are arsenic implanted layers in the oxide film.

In the silicon substrate 103 in which the gate electrode 101 and the spacer 102 formed of a silicon oxide film in a sidewall shape are formed on the gate electrode 101 (STEP 1), a plasma silicon oxide film 104 is deposited by using a plasma CVD method (STEP 2). ). At this time, the plasma CVD method is used, but another method may be used as long as the silicon substrate 103 is not oxidized. For example, a silicon oxide film may be deposited by using a low pressure CVD method. Next, the surface of the plasma silicon oxide film 104 is exposed to plasma 106 of a mixed gas of CF ₄ and oxygen (STEP 3). For example, an oxygen gas flow rate of 500 sccm, a CF ₄ gas flow rate of 5 sccm, a gas pressure of 10 Pa, and a gas pressure of 10 Pa are applied to the upper induction coil in a dry etching apparatus comprising an induction coil at the top and an electrode connected to an RF power source at the bottom Plasma is generated under the condition that the power to be applied is 1000 W and the power to be applied to the lower electrode is 50 W, and the plasma treatment is performed for 2 minutes. At this time, CF ₄ gas was used, but either CHF ₃ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , or C ₄ F ₆ , or two types Other fluorocarbon gases such as the above combinations may be used. Further, since the plasma silicon oxide film 104 is etched when the ratio of the flow rate of the fluorocarbon gas is increased, the oxygen flow rate / fluorocarbon gas flow rate ratio is desirably 50 or more. Under the above conditions, the etching amount of the plasma silicon oxide film is 0.3 nm or less.

Next, the region to be implanted is patterned using the photosensitive resin 105 (STEP 4), and the silicon oxide film exposed to the CF ₄ / O ₂ plasma is wet-etched according to the pattern of the photosensitive resin 105. A pattern is formed (STEP 5). For example, hydrofluoric acid is used as the wet etchant, and the silicon oxide film is removed by processing in a chemical bath for 1 minute. At this time, the plasma silicon oxide film 104 a exposed to the plasma 106 in STEP 3 is in a state in which some of the bonds in the silicon oxide film are cut by the plasma 106. Therefore, the etching amount of the plasma silicon oxide film 104a exposed to the plasma is 4.5 nm while the etching amount of the plasma silicon oxide film when not exposed to the plasma under the above-described wet etching conditions is 0.5 nm. 9 times as much. Since the etching amount of the silicon oxide film forming the spacer 102 is almost equal to 0.6 nm, the selection ratio between the silicon oxide film 104a and the silicon oxide film of the spacer 102 is improved by irradiating the plasma 106. As a result, the plasma silicon oxide film 104 can be selectively removed. Next, the photosensitive resin 105 is removed by washing with sulfurous water (STEP 6). At this time, since the photosensitive resin 105 is before ion implantation, a hardened layer is not formed by implantation, and can be easily removed by washing with sulfuric acid. Therefore, since the photosensitive resin 105 can be removed without using oxygen plasma, the silicon substrate 103 is not oxidized by ashing.

  Next, ion implantation is performed (STEP 7). For example, in the extension region implantation, arsenic is implanted at an acceleration voltage of 3 keV with an implantation amount of 1 × 10 15 atoms per square centimeter. At this time, in the region where the silicon substrate 103 is exposed, arsenic is implanted into the silicon substrate 103 to form an arsenic implanted layer 107. On the other hand, in the region where the plasma silicon oxide film 104 remains, since the acceleration energy of ions is not so large, the arsenic ions stop in the middle of the plasma silicon oxide film 104 to form the arsenic implantation layer 108 and reach the silicon substrate 103. Not reach. That is, the remaining plasma silicon oxide film 104 functions as a mask for dividing the implantation region.

  Next, the remaining plasma silicon oxide film 104 is removed by a wet etching process using hydrofluoric acid or the like (STEP 8). However, it is not always necessary to remove the plasma silicon oxide film 104. If there is no problem in the next process, there is no problem even if the plasma silicon oxide film 104 is left without being removed.

  In the above-described embodiment, hydrofluoric acid is used as a chemical solution for removing the plasma silicon oxide film 104a exposed to plasma in STEP 5, but a chemical solution capable of realizing the same etching amount difference, for example, ammonia overwater, is used. I do not care. Further, although the film deposited on the spacer 102 and the silicon substrate 103 is a silicon oxide film, it may be a silicon nitride film or a silicon carbide film.

As described above, according to the third embodiment, since the photosensitive resin 105 can be removed by wet etching before implantation, it is not necessary to remove the photosensitive resin 105 using oxygen plasma. It is possible to provide a method for manufacturing a semiconductor device capable of suppressing the amount of abrasion due to oxidation of the silicon substrate 103.
(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.

  FIG. 4 is a diagram showing steps in the method for manufacturing a semiconductor device according to the fourth embodiment of the present invention. In FIG. 4, 101 is a gate electrode of a transistor, 102 is a spacer (first insulating film), 103 is a silicon substrate, 105 is a photosensitive resin, 107 is an arsenic implantation layer, 108 is an arsenic implantation layer in an oxide film, 109 Is a plasma FSG film (second insulating film).

  A plasma FSG film 109 is deposited using a plasma CVD method (STEP 2) on the silicon substrate 103 on which the gate electrode 101 and the spacer 102 formed in a sidewall shape with a reduced pressure TEOS film are formed on the gate electrode 101 (STEP 2). . At this time, the plasma CVD method is used, but another method may be used as long as the silicon substrate 103 is not oxidized. For example, a BPSG film may be deposited using the SA-CVD method. Next, the region to be implanted is patterned using the photosensitive resin 105 (STEP 3), and the pattern is formed by wet-etching the plasma FSG film 109 according to the pattern of the photosensitive resin 105 (STEP 4). For example, hydrofluoric acid is used as the wet etchant, and the silicon oxide film is removed by processing in a chemical bath for 1 minute. At this time, by adjusting the concentration of hydrofluoric acid, the selectivity ratio between the plasma FSG film 109 and the reduced pressure TEOS film forming the spacer 102 can be improved, and the plasma FSG film 109 can be selectively removed. Become. It is desirable that the selection ratio of the spacer 102 and the plasma FSG film 109 in the chemical solution is 0.2 or less. Next, the photosensitive resin 105 is removed by washing with sulfuric water (STEP 5). At this time, since the photosensitive resin 105 is before ion implantation, a cured layer is not formed by implantation, and can be easily removed by washing with sulfuric acid. Therefore, since the photosensitive resin 105 can be removed without using oxygen plasma, the silicon substrate 103 is not oxidized by ashing.

  Next, ion implantation is performed (STEP 6). For example, in the extension region implantation, arsenic is implanted at an acceleration voltage of 3 keV with an implantation amount of 1 × 10 15 atoms per square centimeter. At this time, in the region where the silicon substrate 103 is exposed, arsenic is implanted into the silicon substrate 103 to form an arsenic implanted layer 107. On the other hand, in the region where the plasma FSG film 109 remains, since the acceleration energy of ions is not so large, arsenic ions stop in the middle of the plasma FSG film 109 to form the arsenic implantation layer 108 and do not reach the silicon substrate 103. . That is, the remaining plasma FSG film 109 functions as a mask for dividing the implantation region.

  Next, the remaining plasma FSG film 109 is removed by a wet etching process using hydrofluoric acid or the like (STEP 7). However, it is not always necessary to remove the plasma FSG film 109. If there is no problem in the next process, there is no problem even if the plasma FSG film 109 is left without being removed.

  As described above, according to the fourth embodiment, since the photosensitive resin 105 can be removed by wet etching before implantation, it is not necessary to remove the photosensitive resin 105 using oxygen plasma. It is possible to provide a method for manufacturing a semiconductor device capable of suppressing the amount of shaving due to oxidation of the silicon substrate 103.

  The method for manufacturing a semiconductor device according to the present invention is useful for a method for manufacturing a semiconductor device in which the amount of semiconductor substrate scraping is suppressed.

It is a figure which shows the process about the manufacturing method of the semiconductor device in the 1st Embodiment of this invention. It is a figure which shows the process about the manufacturing method of the semiconductor device in the 2nd Embodiment of this invention. It is a figure which shows the process about the manufacturing method of the semiconductor device in the 3rd Embodiment of this invention. It is a figure which shows the process about the manufacturing method of the semiconductor device in the 4th Embodiment of this invention. It is a figure which shows the process about the manufacturing method of the semiconductor device in conventional embodiment.

Explanation of symbols

101 gate electrode 102 spacer 103 silicon substrate 104 plasma silicon oxide film 105 photosensitive resin 106 CF ₄ and oxygen mixed gas plasma 107 arsenic implantation layer 108 arsenic implantation layer 109 plasma FSG film 901 gate electrode 902 spacer 903 silicon substrate 904 photosensitive resin 905 Arsenic injection layer 906 Injection hardened layer 907 Ashing oxide film 908 Substrate scraping

Claims (9)

  Forming a gate electrode of a transistor on a semiconductor substrate and depositing an insulating film on the semiconductor substrate; patterning an ion implantation region on the insulating film using a photosensitive resin; and Removing the insulating film according to a resin pattern using a chemical solution to form the insulating film pattern; removing the photosensitive resin on the insulating film pattern using a chemical solution; and And a step of performing ion implantation on the semiconductor substrate from which the functional resin has been removed.   Forming a gate electrode of a transistor on a semiconductor substrate and depositing an insulating film on the semiconductor substrate; patterning an ion implantation region on the insulating film using a photosensitive resin; and A step of irradiating the semiconductor substrate on which the resin pattern is formed with a plasma of a mixed gas of fluorocarbon gas and oxygen; a step of irradiating the plasma and then removing the photosensitive resin; and the plasma of the insulating film. The step of removing the region irradiated by using a chemical solution to form a pattern of the insulating film, and the step of performing ion implantation on the semiconductor substrate on which the pattern of the insulating film has been formed Method.   2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of irradiating a plasma of a mixed gas of fluorocarbon gas and oxygen on the insulating film after the step of depositing the insulating film on the semiconductor substrate.   4. The method of manufacturing a semiconductor device according to claim 2, wherein a flow rate ratio of oxygen to fluorocarbon gas is 50 or more in the mixed gas of fluorocarbon gas and oxygen. The fluorocarbon gas is CF ₄ , CHF ₃ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , C ₄ F ₆ , or a combination of two or more. 4. The method of manufacturing a semiconductor device according to claim 2, wherein the method is a semiconductor device.   4. The method of manufacturing a semiconductor device according to claim 2, wherein, in the step of removing the insulating film, the chemical solution is hydrofluoric acid or ammonia hydrogen peroxide.   4. The method of manufacturing a semiconductor device according to claim 2, wherein the insulating film is a silicon oxide film, a silicon nitride film, a silicon carbide film, or another silicon compound.   Forming a gate electrode of a transistor on a semiconductor substrate and a first insulating film on a sidewall thereof; and depositing a second insulating film different from the first insulating film on the semiconductor substrate; Forming a pattern of an ion implantation region on the insulating film using a photosensitive resin, and removing the second insulating film using a chemical solution in accordance with the pattern of the photosensitive resin; A step of forming a pattern, a step of removing the photosensitive resin on the pattern of the second insulating film using a chemical solution, and a step of performing ion implantation on the semiconductor substrate from which the photosensitive resin has been removed. A method for manufacturing a semiconductor device.   9. The method of manufacturing a semiconductor device according to claim 8, wherein a selection ratio of the first insulating film and the second insulating film in the chemical solution is 0.2 or less.

Images