JP2000195968A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacture of a semiconductor device, that does not increase the number of manufacturing processes or does not deteriorate the reliability of gate oxide films and MOS transistors to be finally obtained, when MOS transistors having gate oxide films each having a different thickness are formed on a substrate. SOLUTION: Ar ions are implanted in the surface of a silicon substrate 10 of a storage cell part to form an ion implantation region 21. Here, the Ar ion implantation energy is about 15 keV, which is set to that the ion penetrates a sacrificial oxide film 20 and reaches the surface of the silicon substrate 10. Since a resist mask 13 is formed in the logic region, the Ar ions are not implanted in the surface of the silicon substrate 10. In a later process, oxide films, each having a different thickness, are formed simultaneously on the surface of the silicon substrate 10 of the logic region and the storage cell region by one thermal oxidation process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having MOS transistors having different gate oxide films on one substrate.

[0002]

2. Description of the Related Art In recent years, a system LSI having a memory cell section and a logic section on one substrate has been developed and is being used. In such a system LSI, M
Taking an OS transistor as an example, the memory cell section and the logic section have different specifications.

That is, in the memory cell portion, the gate oxide film of the MOS transistor is formed relatively thick in order to ensure reliability, and in the logic portion, the gate oxide film of the MOS transistor is formed relatively thin in order to enable high-speed operation. It is formed.

Also, in a DRAM, a single chip uses a different power supply system, for example, a 5V power supply is used in an input / output unit and a 3.3V power supply is used in a memory cell unit. It is frequently used and MOS transistors having different thicknesses of gate insulating films are formed on one substrate in many cases.

[0005] Hereinafter, an example of a method of manufacturing a semiconductor device having a MOS transistor having a gate insulating film having a different thickness on one substrate will be described with reference to FIGS. 12 will be described. In the following description, a logic part and a memory cell part of a system LSI will be described as an example, and the description will be made on the assumption that two types of MOS transistors having different thicknesses of gate insulating films are manufactured. Here, (a) in FIGS. 8 to 12 is a partial cross-sectional view showing a logic part of the system LSI, and (b) in FIGS. 8 to 12 is a partial cross-sectional view showing a memory cell part of the system LSI.

First, as shown in FIGS. 8A and 8B,
LOCOS oxide film 11 on the main surface of silicon substrate 10
(Field oxide film) is selectively formed, and an element formation region (active region) is formed in each of a logic portion and a memory cell portion.
Is specified.

Thereafter, the first oxidation is performed in the logic section and the memory cell section to form an oxide film 12 having a thickness of about 50 angstroms.

Next, as shown in FIGS. 9A and 9B,
The memory cell portion is covered with a resist mask 13 by photolithography. Note that the resist mask 13 is not formed in the logic portion.

Next, as shown in FIGS. 10A and 10B, the oxide film 12 in the logic portion is removed by wet etching to expose the surface of the silicon substrate 10. The oxide film in the memory cell portion is formed by a resist mask 13
It is not removed because it is covered with.

Next, as shown in FIGS. 11A and 11B, after the resist mask 13 on the memory cell portion is chemically removed by wet processing to expose the oxide film 12,
A cleaning process such as RCA cleaning is performed on the entire silicon substrate 10 as a pre-oxidation process. At this time, the oxide film 12 in the memory cell portion is removed by about several angstroms.

Next, as shown in FIGS. 12A and 12B, a second oxidization is performed in the logic portion and the memory cell portion, so that the logic portion has a thickness of about 50 Å on the silicon substrate 10. An oxide film 120 is formed, and in the memory cell portion, the thickness of the oxide film 12 is increased to form an oxide film 121 having a thickness of about 80 to 100 angstroms.

Thereafter, in the logic section and the memory cell section, MOS transistors are formed using the oxide films 120 and 121 as gate oxide films, respectively, to finally obtain a system LSI.

[0013]

Since the conventional method of manufacturing a semiconductor device has the above-described steps, it has the following problems.

That is, two types of oxide films 1 having different thicknesses
Since two oxidation steps are performed as shown in FIGS. 8 and 12 to form 20 and 121, there is a problem that the number of steps is increased and productivity is reduced.

In the logic section, FIG.
As shown in FIG.
When the resist mask 13 on the memory cell portion is removed as described with reference to FIG. 11B, the silicon substrate 10 in the logic portion is exposed to the resist removing liquid, as shown in FIG. There is a problem that the reliability of the oxide film 120 formed in the process shown in FIG.

In the logic section, FIG.
The oxide film 12 is removed as shown in FIG.
The bird's beak at the end of the COS oxide film 11 is also removed, resulting in a problem that the possibility of occurrence of a defect in a finally obtained MOS transistor increases. This problem will be described in detail with reference to FIGS.

FIG. 13 shows L of the logic section shown in FIG.
FIG. 3 is a detailed view showing an OCOS oxide film 11 part. As shown in FIG. 13, the oxide film 1 extends from the end of the LOCOS oxide film 11.
2 extend. FIGS. 14 and 15 are detailed views of a state where the oxide film 12 shown in FIG. 10A is removed.

FIG. 14 shows a case where the bird's beak at the end of the LOCOS oxide film 11 is maintained in a good state without being excessively removed.
The case where the bird's beak at the end of the oxide film 11 is excessively removed and retreats to form a recess DP at the boundary with the silicon substrate 10 is shown. The reason why such a state occurs is that, when the oxide film 12 is removed, in order to completely remove the oxide film 12, for example, the time of immersion in the removing solution is considered in consideration of the variation in the thickness of the oxide film 12. Such as lengthening
Since extra time is required for the removal process, it is conceivable that the bird's beak is excessively removed depending on the state of formation of the LOCOS oxide film 11.

For example, when a gate oxide film and a gate electrode are formed so as to cover the recess DP, and a bias is applied to the gate electrode during operation of the device, the gate oxide film and the gate electrode Electric field concentration occurs,
The gate oxide film will cause dielectric breakdown.

In the memory cell section, FIG.
As shown in FIG. 1B, a resist mask 13 is formed directly on the oxide film 12, and after removing it, the resist mask 13 is removed.
Since the thickness of the oxide film 12 is increased as shown in FIG. 2B, the oxide film 121 is exposed to various substances, and the reliability of the finally obtained oxide film 121, that is, the gate oxide film is low. was there.

As another method described with reference to FIGS. 8 to 12, as disclosed in Japanese Patent Application Laid-Open No. 10-64898, gates formed in different regions on a substrate with the same thickness are used. After a gate electrode is formed over the oxide film, in one region, fluorine ions or molecular ions containing fluorine are implanted near the junction interface between the gate electrode and the gate oxide film to break Si-O bonds, There is a method in which the thickness of the gate oxide film is increased by substitution and diffusion of free oxygen. However, in this method, fluorine ions are implanted into the substrate immediately below the gate oxide film, and extra carriers are generated. It is assumed that the threshold voltage control becomes difficult.

The present invention has been made in order to solve the above problems, and when forming MOS transistors having different gate oxide films on one substrate, the number of manufacturing steps is increased. It is another object of the present invention to provide a method of manufacturing a semiconductor device which does not impair the reliability of a gate oxide film and the reliability of a finally obtained MOS transistor.

[0023]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a semiconductor device having first and second circuit portions formed on a semiconductor substrate and having different configurations. Forming a first and second portion of a sacrificial oxide film corresponding to portions to be the first and second circuit portions on the semiconductor substrate.
(a), a step (b) of forming a resist mask on the first portion of the sacrificial oxide film, and ions of properties that do not become carriers in the semiconductor layer and do not inhibit the operation of the semiconductor device, Implanting (c) into the surface of the semiconductor substrate below the second portion of the sacrificial oxide film, and removing the first and second portions of the sacrificial oxide film after removing the resist mask (d) and a first thickness of the first thickness by thermal oxidation on the semiconductor substrate to be the first and second circuit portions.
And (e) simultaneously forming a second oxide film having a second thickness larger than the first thickness.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the second aspect, in the step (c), ions of an inert element or ions of a Group IV element are penetrated through the sacrificial oxide film to form the semiconductor. The method includes a step of implanting with energy that reaches the vicinity of the surface of the substrate.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor device according to the third aspect, the step (c) includes the step of:
and a step of implanting with eV energy.

5. The method of manufacturing a semiconductor device according to claim 4, wherein said step (e) is performed under a thermal oxidation condition for forming said first oxide film. Is formed.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device, prior to the step (a), the first and second circuit portions on the semiconductor substrate are defined. A step of selectively forming a field oxide film on the semiconductor substrate, wherein the field oxide film is formed to be thicker in advance by the thickness removed together with the sacrificial oxide film in the step (d). .

According to a sixth aspect of the present invention, in a method of manufacturing a semiconductor device, a first oxide film having a first thickness and a second thickness greater than the first thickness are formed on a semiconductor substrate. A method of manufacturing a semiconductor device having first and second semiconductor elements having a second oxide film, wherein the second oxide film is formed prior to the formation of the second oxide film. Breaking the crystallinity of the surface of the semiconductor substrate of the portion to be,
Simultaneously forming the first and second oxide films by thermal oxidation.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device, the step of destroying the crystallinity of the surface of the semiconductor substrate does not become a carrier in the semiconductor layer, and the operation of the semiconductor device is inhibited The method includes a step (a) of implanting ions having a property not to be formed into a portion of the semiconductor substrate where the second oxide film is to be formed.

9. The method of manufacturing a semiconductor device according to claim 8, wherein in the step (a), an ion of an inert element or an ion of a Group 4 element is used for forming the second oxide film. Implanting into the surface of the semiconductor substrate.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a semiconductor device according to the present invention will be described below with reference to FIGS. In the following description, a logic part and a memory cell part of a system LSI will be described as an example, and the description will be made on the assumption that two types of MOS transistors having different thicknesses of gate insulating films are manufactured. Here, (a) in FIGS. 1 to 7 is a partial sectional view showing a logic part of the system LSI, and (b) in FIGS. 1 to 7 is a partial sectional view showing a memory cell part of the system LSI.

First, as shown in FIGS. 1A and 1B,
A LOCOS (Local Oxid) is provided on the main surface of the silicon substrate 10.
e of Silicon) oxide film 11 (field oxide film) is selectively formed to define an element formation region (active region) in each of the logic portion and the memory cell portion. Note that predetermined impurities are introduced into the surface of the silicon substrate 10.

Thereafter, thermal oxidation is performed in the logic section and the memory cell section to form a sacrificial oxide film 20 having a thickness of about 150 Å. The sacrificial oxide film 20 is referred to as such because it is later removed prior to the formation of the gate oxide film. The sacrificial oxide film 20 on the logic part and the memory cell part is distinguished from each other by the first sacrificial oxide film.
And the second part.

Next, as shown in FIGS. 2A and 2B,
The logic portion is covered with a resist mask 13 by photolithography. Note that the resist mask 13 is not formed in the memory cell portion.

Next, as shown in FIGS. 3A and 3B,
Ar ions are irradiated over the entire surface of the substrate, and Ar ions are implanted into the surface of the silicon substrate 10 in the memory cell portion to form an ion implanted region 21. Here, the implantation energy of Ar ions is about 15 keV, and this value is set so as to penetrate the sacrificial oxide film 20 and reach the surface of the silicon substrate 10. Therefore, the value is changed depending on the thickness of the sacrificial oxide film 20.

Since the resist mask 13 is formed in the logic portion, Ar ions are not implanted into the surface of the silicon substrate 10.

The ions to be implanted here are not limited to Ar ions. For example, ions of an inert element or ions of a group 4 element such as Si do not become carriers in the semiconductor layer. Any ion may be used as long as it does not hinder the operation of.

The sacrificial oxide film 20 is formed on the silicon substrate 10
To prevent the resist mask 13 from directly contacting the surface,
It is provided for the purpose of preventing the concentration distribution of the implanted ions from expanding in the depth direction and destroying the crystallinity only near the surface of the silicon substrate 10. Therefore, the ion implantation region 21 is limited only to the vicinity of the surface of the silicon substrate 10.

Next, as shown in FIGS. 4A and 4B,
The resist mask 13 on the logic portion is chemically removed by wet processing to expose the sacrificial oxide film 20.

Next, as shown in FIGS. 5A and 5B,
The sacrificial oxide film 20 in the logic section and the memory cell section is removed by hydrofluoric acid treatment. Then, a cleaning process such as RCA cleaning is performed on the exposed surface of the silicon substrate 10 as a pre-oxidation process.

The thickness of the sacrificial oxide film 20 is about 150 angstroms. However, in order to completely remove the sacrificial oxide film 20, the thickness of the sacrificial oxide film 20 is about 300 angstroms in consideration of the thickness variation. Is set to remove. Therefore, in order to prevent the bird's beak of the LOCOS oxide film 11 from receding even if the sacrificial oxide film 20 is removed, measures such as forming the LOCOS oxide film 11 thicker in advance are taken.

Next, as shown in FIGS. 6A and 6B,
The exposed surfaces of the silicon substrate 10 in the logic section and the memory cell section are oxidized to simultaneously form an oxide film 22 (first oxide film) and an oxide film 23 (second oxide film), respectively. Here, in the memory cell portion, the crystallinity of the surface of the silicon substrate 10 is broken by the implantation of Ar ions, and the bond between Si is broken, so that the surface state is such that an oxide film is easily grown, When thermal oxidation is performed under the condition that an oxide film 22 having a thickness of about 50 Å is formed in the logic portion, an oxide film 23 having a thickness of 80 to 100 Å is formed in the memory cell portion.
Is formed. The fact that the growth of the oxide film is increased as compared with the growth on a normal silicon substrate is called accelerated oxidation. Since the ions in the ion implantation region 21 are diffused with the formation of the oxide film 23, the ion implantation region 21 is omitted in FIG.

Thereafter, in the logic portion and the memory cell portion, oxide films 22 and 23 are used as gate oxide films, and gate electrodes 16 and 1 made of polysilicon or the like are formed thereon, respectively.
61, the side surfaces of the oxide film 22 and the gate electrode 16 are covered with the sidewall oxide film 17, and the side surfaces of the oxide film 23 and the gate electrode 161 are covered with the sidewall oxide film 171. 22, the source / drain region 18 is self-aligned with the oxide film 23, using the gate electrode 16, the sidewall oxide film 17 as a mask.
A source / drain region 181 is formed in a self-aligned manner using the gate electrode 161 and the sidewall oxide film 171 as a mask, and the whole is covered with the interlayer insulating film 15.
8A and 8B, the contact electrodes 19 and 191 electrically connected to the source / drain regions 18 and 181, respectively, are formed. MOS transistors M1 and M2 are formed respectively.

It is to be noted that ion implantation for accelerated oxidation destroys the crystallinity of the surface of the silicon substrate 10.
In forming the source / drain regions 18 and 181 of the S transistors M1 and M2, annealing is performed after impurity ions are implanted, so that crystallinity is restored.

After the accelerated oxidation, an annealing process may be performed in a nitrogen gas separately from the annealing process for forming the source / drain regions 18 and 181.

<Modification> In the above description, the thermal oxidation is performed under the condition that the oxide film 22 having a thickness of about 50 angstroms is formed in the logic section, so that the memory cell section has a thickness of 80 to 100 angstroms. In other words, thermal oxidation is performed under the condition that oxide film 23 having a thickness of 80 to 100 angstroms is formed in the memory cell portion, so that 50 angstroms is formed in the logic portion. It goes without saying that the oxide film 22 having a thickness of about the same may be formed. However, in the case where the thickness of the oxide film in the logic portion where the ion implantation is not performed is used as an index, data such as the growth rate of the oxide film is established, and there is an advantage that the thickness can be easily controlled.

In the above description, the system L
Taking the logic part and the memory cell part of the SI as an example, the case of forming oxide films of two kinds of thicknesses has been described.
The application of the present invention is not limited to this. The present invention can be applied to any semiconductor device having a different configuration, more specifically, a semiconductor device having MOS transistors having different specifications. However, the present invention is not limited to this.

For example, a first resist mask is formed from the beginning so that no Ar ions are implanted into the first region, and Ar ions are implanted into the second and third regions at a first dose. After that, a second resist mask is formed in the second region, and Ar ions are further implanted into the third region so as to have the second implantation amount.
By changing the amount of ion implantation to form regions having different degrees of accelerated oxidation, it is possible to form oxide films having two or more types of thicknesses.

In the above description, the formation of a gate oxide film of a MOS transistor has been described as an example. However, oxidation is promoted by destroying the crystallinity of the surface of the silicon substrate by implanting Ar ions or the like. From the viewpoint of utilizing the fact that the present invention is applied, the present invention is not limited to the formation of a gate oxide film of a MOS transistor, but is applied to a semiconductor device in which oxide films having different thicknesses are formed on one silicon substrate. If so, the present invention can be applied.

<Characteristic Effects> According to the method of manufacturing a semiconductor device according to the present invention described above, the region where the crystallinity is destroyed by ion implantation to perform accelerated oxidation is formed on one semiconductor substrate. Since the gate oxide film having a different thickness is formed only by one oxidation step after removing the sacrificial oxide film, the number of steps can be reduced,
In addition, since the step between the first oxidation and the second oxidation can be omitted, the oxide film is not exposed to the air or chemical for a long time, so that the productivity is improved and the gate oxide film is improved. Reliability is improved.

Further, since the exposed silicon substrate is not exposed to the resist removing solution, the reliability of the finally obtained oxide film, that is, the gate oxide film does not decrease.

Further, since the sacrificial oxide film is formed in the logic section and the memory cell section, even if the sacrificial oxide film is removed, the LO
By forming a thick LOCOS oxide film in advance so that bird's beak of the COS oxide film does not recede, L
MOS caused by bird's beak retreat of OCOS oxide film
It is possible to prevent occurrence of a defect in the transistor.

Further, since no resist mask is formed on the oxide film formed after the removal of the sacrificial oxide film, the oxide film which will eventually become the gate oxide film is not exposed to various substances. The reliability of the gate oxide film does not decrease.

In addition, ions implanted into the silicon substrate for accelerated oxidation do not become carriers in the semiconductor layer, such as inactive element ions such as Ar, or ions of Group 4 elements such as Si. Since the ions do not hinder the operation of the device, there is no problem that extra carriers are generated in the semiconductor layer and control of the threshold voltage becomes difficult.

[0055]

According to the method of manufacturing a semiconductor device according to the first aspect of the present invention, a region where accelerated oxidation is performed by destroying crystallinity by ion implantation on one semiconductor substrate, and a region where normal oxidation is performed. The first and second oxide films having different thicknesses to become, for example, gate oxide films are formed only by one oxidation step after the removal of the sacrificial oxide film.
The number of steps for forming the gate oxide film can be reduced, and the step between the first oxidation and the second oxidation can be omitted.
Since the oxide film is not exposed to the atmosphere or the chemical for a long time, the productivity is improved, and the reliability of the gate oxide film is improved. In removing the resist mask, a second circuit portion on the semiconductor substrate is provided with a second sacrificial oxide film.
Is formed, the silicon substrate is not exposed to the resist removing solution, and the reliability of the finally obtained oxide film, that is, the gate oxide film does not decrease. In addition, since a resist mask is not formed on the first and second oxide films formed after the removal of the sacrificial oxide film, the first and second oxide films that ultimately become the gate oxide film have various shapes. There is no exposure to the substance, and the reliability of the gate oxide film is not reduced. Further, ions implanted into the semiconductor substrate do not become carriers in the semiconductor layer and do not hinder the operation of the semiconductor device. Therefore, extra carriers are generated in the semiconductor layer and the threshold voltage is reduced. Does not occur.

According to the method of manufacturing a semiconductor device according to the second aspect of the present invention, it is possible to form a surface state in which an oxide film is easily grown by destroying the crystallinity near the surface of the semiconductor substrate.

According to the third aspect of the present invention, the thickness of the sacrificial oxide film is, for example, 1 by implanting argon ions at an energy of 15 keV.
In the case of about 50 angstroms, argon ions penetrate the sacrificial oxide film and reach the vicinity of the surface of the semiconductor substrate, and the crystallinity of the surface can be destroyed without the ion concentration distribution expanding in the depth direction. .

According to the method of manufacturing a semiconductor device according to the fourth aspect of the present invention, under the conditions for forming the first oxide film formed on the semiconductor substrate whose surface crystallinity is not destroyed by ion implantation. Since the second oxide film is formed, it is easy to control the thickness of the first and second oxide films.

According to the method of manufacturing a semiconductor device according to the fifth aspect of the present invention, the field oxide film is formed thicker in advance by the thickness to be removed together with the sacrificial oxide film. It is possible to prevent the occurrence of defects in the semiconductor device due to the retreat of the bird's beak.

According to the method of manufacturing a semiconductor device according to the sixth aspect of the present invention, a region where the crystallinity is partially destroyed to perform accelerated oxidation and a region where normal oxidation is performed on one semiconductor substrate. And the first and second oxide films having different thicknesses to become, for example, gate oxide films are formed only by one oxidation step, so that the number of gate oxide film formation steps can be reduced. Further, since the substrate does not need to be taken out of the oxidation furnace, and the oxide film is not exposed to the atmosphere or the chemical for a long time, the productivity is improved and the reliability of the gate oxide film is improved.

According to the method of manufacturing a semiconductor device according to the seventh aspect of the present invention, since the crystallinity of the semiconductor substrate is destroyed by ion implantation, it is possible to easily set the region where the enhanced oxidation is performed. Further, ions implanted into the semiconductor substrate do not become carriers in the semiconductor layer and do not hinder the operation of the semiconductor device. Therefore, extra carriers are generated in the semiconductor layer and the threshold voltage is reduced. Does not occur.

According to the method of manufacturing a semiconductor device according to the eighth aspect of the present invention, crystallinity near the surface of the semiconductor substrate is destroyed, and a surface state in which an oxide film is easily grown can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a manufacturing process of a semiconductor device manufacturing method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of a semiconductor device manufacturing method according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a manufacturing step in the embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 4 is a cross-sectional view for explaining a manufacturing process in the embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 5 is a cross-sectional view for explaining a manufacturing process in the embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 6 is a cross-sectional view for explaining a manufacturing process in the embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 7 is a cross-sectional view for explaining a manufacturing step in the embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 8 is a cross-sectional view illustrating a manufacturing process of a conventional method for manufacturing a semiconductor device.

FIG. 9 is a cross-sectional view illustrating a manufacturing process of a conventional method for manufacturing a semiconductor device.

FIG. 10 is a cross-sectional view illustrating a manufacturing process of a conventional method for manufacturing a semiconductor device.

FIG. 11 is a cross-sectional view illustrating a manufacturing step in a conventional method of manufacturing a semiconductor device.

FIG. 12 is a cross-sectional view illustrating a manufacturing step of a conventional method for manufacturing a semiconductor device.

FIG. 13 is a diagram illustrating a problem of a conventional method of manufacturing a semiconductor device.

FIG. 14 is a diagram illustrating a problem of a conventional method of manufacturing a semiconductor device.

FIG. 15 is a diagram illustrating a problem of a conventional method of manufacturing a semiconductor device.

[Explanation of symbols]

10 silicon substrate, 11 LOCOS oxide film, 20
Sacrificial oxide film, 22, 23 Oxide film, 21 Ion implantation region.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/8242 H01L 21/265 602A 27/08 102H 27/10 681F F-term (Reference) 5F048 AB01 AB03 AC01 BB16 BG12 DA24 5F058 BA20 BC01 BC02 BE07 BF52 BJ01 5F083 GA24 GA27 NA02 PR14 PR36 PR43 PR44 PR45 PR53 PR54 PR55 ZA07 ZA08 ZA12 ZA13

Claims (8)

[Claims] 1. A method of manufacturing a semiconductor device having first and second circuit portions formed on a semiconductor substrate and having different configurations, comprising: (a) the first and second circuit portions on the semiconductor substrate; Forming a first and a second portion of a sacrificial oxide film corresponding to a portion to be a circuit portion of (b); and (b) forming a resist mask on the first portion of the sacrificial oxide film; (c) implanting into the surface of the semiconductor substrate below the second portion of the sacrificial oxide film ions that do not become carriers in the semiconductor layer and do not inhibit the operation of the semiconductor device; (d) removing the first and second portions of the sacrificial oxide film after removing the resist mask; and (e) thermally oxidizing the semiconductor substrate to be the first and second circuit portions. The first oxide film having the first thickness and the first thickness Forming a thick second oxide film at the same time as the second oxide film. 2. The method according to claim 1, wherein the step (c) comprises implanting ions of an inert element or ions of a Group 4 element with an energy that penetrates the sacrificial oxide film and reaches near the surface of the semiconductor substrate. Claim 1 comprising
The manufacturing method of the semiconductor device described in the above. 3. The method of manufacturing a semiconductor device according to claim 2, wherein said step (c) includes a step of implanting argon ions at an energy of 15 keV. 4. The method according to claim 1, wherein the step (e) is performed under a thermal oxidation condition for forming the first oxide film.
2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of forming a second oxide film. 5. Prior to the step (a), a field oxide film is selectively formed on the semiconductor substrate so as to define regions to be the first and second circuit portions on the semiconductor substrate. 2. The method according to claim 1, further comprising a step of: forming the field oxide film thicker in advance by the thickness removed together with the sacrificial oxide film in the step (d). 3. 6. A first and a second oxide film formed on a semiconductor substrate and having a first oxide film of a first thickness and a second oxide film of a second thickness greater than the first thickness. A method for manufacturing a semiconductor device including a second semiconductor element, wherein prior to forming the second oxide film, crystallinity of a surface of the semiconductor substrate in a portion where the second oxide film is formed is destroyed. A method for manufacturing a semiconductor device, comprising: a step of simultaneously forming the first and second oxide films by thermal oxidation. 7. The step of destroying the crystallinity of the surface of the semiconductor substrate includes the steps of: (a) removing ions that do not serve as carriers in the semiconductor layer and do not inhibit the operation of the semiconductor device into the second oxide; 7. The method for manufacturing a semiconductor device according to claim 6, further comprising a step of implanting a portion of the semiconductor substrate on which a film is to be formed. 8. The method according to claim 1, wherein the step (a) includes a step of injecting an ion of an inert element or an ion of a Group 4 element into a surface of the semiconductor substrate at a portion where the second oxide film is formed. Item 8. The method for manufacturing a semiconductor device according to Item 7.