JP2003100868A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: An etching rate of a gate sidewall insulating film made of a silicon nitride film formed by an LP-CVD method using HCD as a source gas is made sufficiently lower than an etching rate of a natural oxide film. And removing the natural oxide film without reducing the thickness of the gate sidewall insulating film. A nitrogen density on a side surface of a gate sidewall insulating film made of a silicon nitride film is set to 1 × 10 ¹⁴ cm ⁻² or more.
A natural oxide film is removed by wet etching using HF at a setting of × 10 ¹⁵ cm ⁻² or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device including a member made of a silicon nitride film and a method of manufacturing the same, and particularly, the etching rate on the side surface of the member made of the silicon nitride film is slower than that of the silicon oxide film. And a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in an LSI, multi-layer wiring has been often used to increase the degree of integration. In this type of multilayer wiring, in order to realize wiring with a high degree of integration, a technique of directly connecting not only vertically adjacent wiring layers but also layers separated by two or more layers is used.

At this time, it is necessary to insulate the plug connecting the wirings separated by two layers or more and the wiring (intermediate wiring) existing between the wirings separated by two layers or more. For this reason, in a multilayer wiring that directly connects layers separated by two or more layers, a design is usually made with a sufficient margin so that the connection hole in which the plug is embedded does not reach the intermediate wiring due to misalignment between layers. ing.

On the other hand, in recent years, a method of forming a plug in a self-aligned manner with respect to the wiring in order to form a wiring with a higher degree of integration (SAC (Self-Aligned Contact) process).
Is being done. This method will be described below with reference to FIG.

First, as shown in FIG. 5A, a silicon oxide film 8 as a first interlayer insulating film is formed on the first wiring 81.
2 is formed, and then the second wiring 83 and the first silicon nitride film 84 are formed on the silicon nitride film 82.

Next, as shown in FIG. 5B, a second silicon nitride film (sidewall insulating film) 85 is formed on the sidewalls of the second wiring 83 and the first silicon nitride film 84, and subsequently, A silicon oxide film 86 as a second interlayer insulating film is deposited on the entire surface, and then a contact pattern 87 made of photoresist is formed on the silicon oxide film 86.

After that, RIE (Reactive Ion Etching)
Under the condition that the etching rate of silicon oxide is faster than that of silicon nitride, the silicon oxide films 86 and 81 are nitrided with the contact pattern 87 as a mask as shown in FIG. 5C. The films 84 and 85 are selectively etched to form a contact hole 88 reaching the first wiring 81 in a self-aligned manner.

After that, as shown in FIG. 5D, the contact pattern 87 is peeled off.

Next, as shown in FIG. 5E, a metal film to be a third wiring and a plug (third wiring / plug) 89 for connecting the third wiring and the first wiring 81 is formed. , The inside of the connection hole 88 and the silicon oxide film 86 are deposited, and then the metal film is patterned to form a third wiring
The plug 89 is formed.

According to this method, since the silicon nitride films 84 and 85 act as a mask for the second wiring 83 in the etching step of FIG. 5C, even if the contact pattern 87 is displaced, the second Wiring 83 is not etched. Therefore, it is not necessary to provide a margin between the connection hole 88 and the second wiring 83. That is, it is not necessary to increase the distance between the two second wirings 83 shown in the figure.

As a method for forming the silicon nitride film 85 for covering the second wiring 83, the CVD method, particularly the LP-CVD method is preferable. As another method for depositing silicon nitride, a PE-CVD method is generally used, but the second wiring 83 is used.
Is significantly inferior to the LP-CVD method in terms of step coverage on the side surface of the.

However, conventional SiH ₂ Cl ₂ (DCS)
In the LP-CVD method using N and NH ₃ as source gas,
A high temperature heating process of 700 ° C. or higher is required. For this reason, the wiring material formed before this is not a low melting point material such as Al but a high melting point material such as W.

Further, in the high temperature heating process at 700 ° C. or higher, as shown in FIG. 6, the barrier metal film 94 cannot prevent the reaction between the metal forming the first wiring 81 and the impurity diffusion layer 90. Therefore, the impurity diffusion layer 90 and the first
There are problems such as an increase in contact resistance with the wiring 81 and an increase in leak current. In FIG. 6, 91 is a silicon substrate, 92 is an element isolation insulating film (STI), 93
Is an interlayer insulating film, and 94 is a barrier metal film.

In order to solve these problems, it has been proposed to use Si ₂ Cl ₆ (HCD) as a source gas. Using this gas system, a silicon nitride film can be deposited even at a film forming temperature of 650 ° C. or lower.

However, when HCD is used as the source gas, L
The silicon nitride film formed by the P-CVD method is an LSI
The etching rate by the liquid containing HF (HF solution) that is frequently used in the manufacturing process of is high.

Therefore, in the step of removing the natural oxide film with the HF solution, which is performed after the step of FIG. 5C, the silicon nitride films 84 and 85 are etched, and the silicon nitride films 84 and 85 are thinned or disappear. . As a result, it becomes difficult to maintain the insulation between the third wiring / plug 89 and the second wiring 83.

[0017]

As described above, the conventional S
In the AC process, the LP-CVD method using HCD as a source gas is adopted as a method of forming a silicon nitride film that covers wiring from the viewpoint of step coverage and film formation temperature.

The silicon nitride film formed by this kind of method has a high etching rate by the HF solution used for removing the natural oxide film. Therefore, the silicon nitride film is thinned or disappears in the step of removing the natural oxide film with the silicon nitride film as the sidewall insulating film exposed.
As a result, there arises a problem that it becomes difficult to maintain insulation between the plug connecting the first wiring and the third wiring and the second wiring.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor device provided with an insulating member made of a silicon nitride film capable of preventing thinning and disappearance due to HF, and manufacturing thereof. To provide a method.

[0020]

Among the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

That is, to achieve the above object, a semiconductor device according to the present invention is a substrate and a member formed on the substrate, at least a part of a side surface of which is exposed, and which is made of a silicon nitride film. When the member is divided into two, a surface layer including the side surface and a layer deeper than the surface layer, the volumetric density of nitrogen in the surface layer has a distribution in the depth direction and is higher than that of the surface layer. The surface, wherein the volume density of nitrogen in the deep layer is substantially constant in the depth direction, and is obtained by subtracting the volume density of nitrogen in the layer deeper than the surface layer from the volume density of nitrogen in the surface layer. A member having a surface density of 1 × 10 ¹⁴ cm ⁻² or more and 5 × 10 ¹⁵ cm ⁻² or less obtained by integrating the volume density distribution of nitrogen in the layer in the depth direction of the surface layer. It is characterized by having.

According to the present invention, the nitrogen density of the exposed portion of the side surface of the member made of the silicon oxide film is set to 1 × 10 ¹⁴ cm ⁻² or more and 5 × 10 ¹⁵ cm ⁻² or less, so that the exposed portion of It is possible to realize a semiconductor device provided with a member made of a silicon nitride film and a method for manufacturing the same, which can increase the etching resistance by HF and can prevent thinning and disappearance by HF.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

(First Embodiment) When a silicon nitride film deposited by LP-CVD at 625 ° C. using HCD as a silicon source is wet-etched with a solution containing 0.25% HF, the silicon nitride film is etched. The rate is
Immediately after the deposition, it is almost the same as that of the silicon oxide film formed by thermal oxidation, and even after RTA in N ₂ at 900 ° C. for 20 seconds, the etching rate ratio to the thermal oxide film is
It is about 0.45 times.

However, according to experiments by the inventors,
It has been clarified that the etching rate can be sufficiently reduced by introducing a predetermined amount of nitrogen into the silicon nitride film.

FIG. 1 shows a case of using HCD and NH ₃ gas.
When nitrogen ions are implanted into a silicon nitride film deposited by the LP-CVD method at 5 ° C. and RTA is performed in N ₂ at 900 ° C. for 20 seconds, the sample obtained is etched with a 0.25% HF aqueous solution. It is a figure which shows the relationship between the dose amount of nitrogen ion, and the etching rate of a silicon nitride film. For reference, FIG. 1 also shows the etching rate of the silicon nitride film to which nitrogen ions are not introduced.

As can be seen from FIG. 1, the surface density is 1 × 10.
^If nitrogen ions are implanted so that the nitrogen concentration is ¹⁴ or more and 5 × 10 ¹⁵ cm ⁻² or less, the etching rate becomes slow.
The etching rate is nitrogen concentration of 1 × 10 ¹⁶ cm ^-2 is earlier Conversely, this structure of the silicon nitride film is interpreted to be due to disturbed by physical stress.

However, when the ion implantation method is used, nitrogen cannot be efficiently introduced into the side surface of the silicon nitride film because the directivity of nitrogen ions is extremely high. Also,
It is easy to give physical damage to the silicon nitride film. In order to efficiently introduce nitrogen into the side wall portion, it is necessary to use particles containing nitrogen having low directivity.

As a method of efficiently introducing nitrogen into the side surface of the silicon nitride film using such particles of nitrogen having a low directivity, a method of using plasma containing nitrogen can be considered.

For example, after the connection hole 88 is opened by the same method as shown in FIGS. 5A to 5D, as shown in FIG. 2, for example, under a pressure of about 100 mTorr, N
_The substrate on which the silicon nitride film 85 is formed is exposed to the plasma 1 containing nitrogen generated by applying a high frequency of about 500 W to a gas containing nitrogen such as ₂ or NH ₃ .

As a result, the exposed side surface of the silicon nitride film 85 has a nitrogen concentration of 1 which is difficult to achieve by ion implantation.
It is possible to form the high-concentration nitrogen layer 2 having a density of x10 ^{14 to} 5x10 ¹⁵ cm ^-2 . The high concentration nitrogen layer 2 is also formed on the exposed upper surface of the silicon nitride film 85. Further, in the figure, 3 indicates the high-concentration nitrogen layer 3 (surface layer) formed on the upper surface and side wall surface (side surface of the connection hole) of the silicon oxide film 82 by the above plasma treatment.

The nitrogen concentration (cm ^-3 ) in the depth direction of the silicon nitride film 85 below the high concentration nitrogen layer 2 is substantially constant. This is because the silicon nitride film 85 below the high-concentration nitrogen layer 2 has almost no nitrogen added by plasma doping, and substantially only the nitrogen that the silicon nitride film originally has.

Since the silicon nitride film 85 below the high-concentration nitrogen layer 2 contains almost no nitrogen added by plasma doping, the silicon nitride film 85 below the high-concentration nitrogen layer 2 does not contain nitrogen. Nitrogen concentration (cm ^-3 ) is
It becomes lower than that of the high concentration nitrogen layer 2.

That is, using the method of this embodiment,
When the silicon nitride film 85 (member made of a silicon nitride film) on which the high-concentration nitrogen layer 2 is formed is divided into a high-concentration nitrogen layer 2 and a layer deeper than the high-concentration nitrogen layer 2, nitrogen in the high-concentration nitrogen layer 2 The volume density has a distribution in the depth direction, the volume density of nitrogen in a layer deeper than the high-concentration nitrogen layer 2 is substantially constant in the depth direction, and the volume density of nitrogen in the high-concentration nitrogen layer 2 The high-concentration nitrogen layer 2 obtained by subtracting the volumetric density of nitrogen in the layer deeper than the high-concentration nitrogen layer 2 from
The surface density of the high-concentration nitrogen layer 2 obtained by integrating the volume density distribution of nitrogen in the depth direction of the high-concentration nitrogen layer 2 is 1
It was found that it was not less than × 10 ¹⁴ cm ^{−2 and not} more than 5 × 10 ¹⁵ cm ⁻² .

After forming the high-concentration nitrogen layer 2, if necessary, heating is performed at a relatively low temperature of about 600 ° C. for about 30 to 60 minutes, or at a temperature of about 800 ° C. for 20 to 20 ° C.
By heating for a short time of about 30 seconds, nitrogen can be introduced more efficiently.

Thus, according to the present embodiment, by forming the high-concentration nitrogen layer 2 on the exposed surface of the silicon nitride film 85 by the nitrogen plasma treatment, for example, cleaning for the purpose of removing a natural oxide film or the like is performed. , HF can be used to prevent thinning of the silicon nitride film 85 covering the side wall of the second wiring 83, and insulation between the third wiring / plug 89 and the second wiring 83 can be prevented. Will be able to keep.

(Second Embodiment) FIGS. 3 and 4 are sectional views showing a manufacturing process of a semiconductor device according to a second embodiment of the present invention.

First, as shown in FIG.
SiO on the substrate 21₂With a thickness of about 5 nm
Insulating film 22, silicon or silicon germanium
Conducting B, As, P, etc. on a 70 nm thick semiconductor film made of
1 x 10 electrically conductive impurities²⁰cm ^-3Low resistance obtained by adding the above
Semiconductor film 23, thin W nitride film 24 having a thickness of about 5 nm,
A W film 25 and a silicon nitride film 26 with a thickness of about 200 nm are formed.
The gate pattern is formed on the silicon nitride film 26 sequentially.
Forming a photoresist pattern 27 having a pattern.
Instead of the silicon substrate 21, an SOI substrate or silicon
A substrate containing germanium may be used. Crystal of semiconductor film 23
The structure is, for example, polycrystalline.

Next, as shown in FIG. 3B, the silicon nitride film 2 is formed by using the photoresist pattern 27 as a mask.
6 is etched by the RIE method, and the pattern of the photoresist pattern 27 is transferred to the silicon nitride film 26. As a result, a hard mask made of the silicon nitride film 26 is obtained.

Next, as shown in FIG. 3C, after removing the photoresist pattern 27, a high frequency of about 500 W is applied to a gas containing nitrogen such as N ₂ or NH ₃ under a pressure of about 100 mTorr. The silicon substrate 21 on which the silicon nitride film 26 is formed is exposed to plasma containing nitrogen generated by the above process, and the surface of the silicon nitride film 26 has a nitrogen density of 1 × 10 ^{14 to} 5 × 10 ¹⁵ cm ^-2 in terms of surface density. Forming a high-concentration nitrogen layer 28 having The nitrogen concentration of the silicon nitride film 26 in the portion where the high concentration nitrogen layer 28 is not formed is 1 ×
The value is lower than 10 ¹⁴ .

At this time, the high-concentration nitrogen layer 29 is simultaneously formed on the surface of the W film 25, but the high-concentration nitrogen layer 29 is removed at the same time without affecting the subsequent steps such as RIE. It

After forming the high-concentration nitrogen layers 28 and 29, if necessary, at a relatively low temperature of about 600 ° C. for 30 minutes to 60 minutes.
Nitrogen can be introduced more efficiently by heating for about a minute or by heating at a temperature of about 800 ° C. for a short time of about 20 to 30 seconds.

Next, as shown in FIG. 3D, the W film 25, the W nitride film 24 and the semiconductor are formed by using the silicon nitride film 26 (hard mask) having the high concentration nitrogen layer 28 formed on the surface as a mask. The film 23 is etched by the RIE method to form the gate electrode 30 composed of the W film 25, the W nitride film 24, and the semiconductor film 23. At this time, the high concentration nitrogen layer 29 formed on the surface of the W film 25 is removed.

Next, heat treatment at about 800 ° C. is performed in a mixed atmosphere of H ₂ and H ₂ O using the method disclosed in, for example, Japanese Patent Application Laid-Open No. 59-132136, and the result is shown in FIG. 3 (e). As described above, the side surface (gate side wall) of the semiconductor film 23 is oxidized without oxidizing the W film 25 and the W nitride film 24, and the oxide film 31
To form. By oxidizing the side wall of the gate and increasing the thickness of the oxide film in the portion in contact with the gate insulating film 22, the reliability of the gate insulating film 22 can be improved.

Next, as shown in FIG. 4F, impurity ions are implanted into the surface of the substrate by using the gate electrode 30 and the like as a mask to form the impurity diffusion layer 32 constituting the source / drain extension in a self-aligned manner. To do.

In all the steps from FIG. 3C to FIG. 4F, even if wet etching or wet cleaning is performed with a solution containing HF, the high concentration nitrogen layer 2
9 is formed, the thickness and width of the hard mask 26 are not reduced.

Next, as shown in FIG. 4G, a silicon nitride film 33 having a thickness of about 50 nm is deposited on the entire surface so as to cover the gate portion including the gate electrode 30 and the like.

Next, as shown in FIG. 4H, the entire surface of the silicon nitride film 33 is etched by the RIE method, and the silicon nitride film 33 is selectively left on the sidewalls of the gate electrode 30 and the silicon nitride film 26. Let At this time, the high concentration nitrogen layer 28 formed on the upper surface of the silicon nitride film (hard mask) 26 is removed.

Next, as shown in FIG. 4 (i), 100 m
The silicon nitride film (gate side wall insulating film) 33 and the silicon nitride film 33 are exposed to plasma containing nitrogen generated by applying a high frequency of about 500 W to a gas containing nitrogen such as N ₂ or NH ₃ under a pressure of about Torr. A high concentration nitrogen layer 34 having a nitrogen concentration of 1 × 10 ^{14 to} 5 × 10 ¹⁵ cm ⁻² is formed on the surface of 26 (hard mask).

After forming the high-concentration nitrogen layer 34, if necessary, heating is performed at a relatively low temperature of about 600 ° C. for about 30 to 60 minutes, or at a temperature of about 800 ° C. for 2 minutes.
Nitrogen can be introduced more efficiently by heating for a short time of about 0 to 30 seconds.

After that, the step of performing wet etching or wet cleaning with a solution containing HF is continued, but the silicon nitride film (gate sidewall insulating film) 35 and the silicon nitride film (hard mask) 26 are formed on their surfaces. The high-concentration nitrogen layer 34 prevents thinning and disappearance, and as a result, insulation between the gate electrode 30 and the source / drain electrodes formed in the next step can be maintained.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the case of the silicon nitride film used in the SAC process or the gate process has been described, but the present invention can be applied to the silicon nitride film used in other processes. Further, the film formation temperature of the silicon nitride film is preferably a low temperature of 700 ° C. or lower. Such a low film forming temperature is
It can be easily realized by using the LP-CVD method using HCD as a source gas.

Further, in the above embodiment, as a method of introducing a predetermined amount of nitrogen into the exposed side surface of the insulating member made of a silicon nitride film, a method of exposing it to plasma containing nitrogen, that is, the momentum distribution of nitrogen is anisotropic. Although the insulating member made of the silicon nitride film is exposed to the environment where it does not occur, it may be introduced by using another method. For example, a method using oblique ion implantation is possible.

Furthermore, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent features are deleted from all the constituent features shown in the embodiment, if the problem described in the column of the problem to be solved by the invention can be solved, the constituent feature is deleted. Can be extracted as an invention.

In addition, various modifications can be made without departing from the scope of the present invention.

[0057]

As described above in detail, according to the present invention, H
It becomes possible to realize a semiconductor device including an insulating member made of a silicon nitride film and a method for manufacturing the same, which can prevent thinning and disappearance due to F.

[Brief description of drawings]

FIG. 1 is a plan view showing an RTA performed by implanting nitrogen ions into a silicon nitride film deposited by LP-CVD using HCD and NH ₃ gas.
The figure which shows the relationship between the dose amount of nitrogen ion and the etching rate when the sample obtained by carrying out is etched with the HF aqueous solution.

FIG. 2 is a sectional view showing a manufacturing process of the semiconductor device according to the first embodiment of the invention.

FIG. 3 is a sectional view showing a manufacturing process of a semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the manufacturing process of the semiconductor device, following FIG. 3;

FIG. 5 is a sectional view showing a conventional SAC process.

FIG. 6 is a sectional view for explaining a conventional problem.

[Explanation of symbols]

1 ... Plasma containing nitrogen 2,3 ... High concentration nitrogen layer 21 ... Silicon substrate 22 ... Gate insulating film 23 ... Low resistance semiconductor film 24 ... W nitride film 25 ... W film 26 ... Silicon nitride film (hard mask) 27 ... Photoresist pattern 28, 29 ... High concentration nitrogen layer 30 ... Gate electrode 31 ... Oxide film 32 ... Impurity diffusion layer 33 ... Silicon nitride film (gate sidewall insulating film) 34 ... High concentration nitrogen layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/3205 H01L 29/78 301P 21/336 21/90 P 29/78 21/88 Q 29/78 301Y (71) Applicant 596068419 Winbond Electronics Corp. Science Electronics Basin Industrial Road Creation Road III No. 4 No. 4 in Cinchu City, Taiwan. 4, Creation Road I II, Science-Based Industrial Park, Hsinchu City, Taiwan, R .; OC (72) Inventor Yasushi Akasaka 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Inside the Toshiba Yokohama office of the stock company (72) Inventor Zhou Bahua Taiwan Hsinchu Science and Industrial Park 300 Kenshinsanji 4 ( 72) Inventor Toshiro Nakanishi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (reference) 4M104 AA01 AA03 AA09 BB00 BB01 CC05 DD02 DD09 DD16 DD17 DD55 DD65 DD71 DD78 DD80 DD89 EE05 EE09 EE17 FF14 5F033 GG00 GG01 HH03 HH04 HH19 HH34 LL04 MM07 MM15 NN37 QQ08 QQ09 QQ10 QQ13 QQ19 QQ28 QQ37 QQ58 QQ60 QQ64 QQ73 QQ74 QQ76 QQ82 QQ90 RR04 RR06 SS13 TT08 VV06 WW04 5F058 BA08 BA20 BC08 BF04 BF24 BF30 BH16 BJ04 5F140 AC36 BA01 BA05 BF04 BF20 BF21 BF27 BG09 BG12 BG14 BG22 BG26 BBK27 B27 B27 B57B27 BG53 BG53 BG49 BG51 BG51 BG51 BG51 BG49 BG49 BG49

Claims (9)

[Claims] 1. A substrate and a member formed on the substrate and having at least a part of its side surface exposed and made of a silicon nitride film, the member being a surface layer including the side surface and deeper than the surface layer. When divided into two, the surface layer has a volumetric distribution of nitrogen in the depth direction, and the volumetric density of nitrogen in a layer deeper than the surface layer is substantially constant in the depth direction. And the volumetric density of nitrogen in the surface layer, obtained by subtracting the volumetric density of nitrogen in a layer deeper than the surface layer, the volumetric density distribution of nitrogen in the surface layer, the depth direction of the surface layer surface density of the surface layer obtained by integrating the is, 1 × 10 ¹⁴
A semiconductor device comprising a member having a size of cm ^{−2 to} 5 × 10 ¹⁵ cm ⁻² . 2. The semiconductor device according to claim 1, wherein the member is a member made of a silicon nitride film formed on a side wall of the electrode, or a mask made of a silicon nitride film. 3. A step of forming a silicon nitride film on a substrate; a step of etching the silicon nitride film to form a member made of the silicon nitride film, at least a part of a side surface of which is exposed; A method of manufacturing a semiconductor device, comprising: a step of introducing a predetermined amount of nitrogen into the exposed side surface; and a step of removing an oxide film on a region including the member. 4. The predetermined amount is 1 × 10 ¹⁴ cm ⁻² or more and 5 ×
^{4. The} method for manufacturing a semiconductor device according to claim 3, wherein it is 10 ¹⁵ cm ⁻² or less. 5. In the step of forming the silicon nitride film on the substrate, L is used as a film forming method of the silicon nitride film.
The method of manufacturing a semiconductor device according to claim 3, wherein a P-CVD method is used. 6. The method for manufacturing a semiconductor device according to claim 5, wherein a silicon raw material containing hexachlorodisilane is used in the step of forming the silicon nitride film on the substrate. 7. The step of introducing a predetermined amount of nitrogen to the exposed side surface of the member, the substrate on which the member is formed is exposed to a plasma containing nitrogen.
7. The method of manufacturing a semiconductor device according to any one of items 6 to 6. 8. The step of removing an oxide film on a region including the member is characterized in that the substrate on which the member is formed is immersed in a liquid containing HF or exposed to an atmosphere containing HF. A method of manufacturing a semiconductor device according to claim 3. 9. The member according to claim 3, wherein the member is a spacer made of a silicon nitride film formed on a side wall of the gate electrode, or a mask made of a silicon nitride film. Of manufacturing a semiconductor device of.