JPH0774167A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing a semiconductor device that has excellent electrical characteristics and has an improved hot carrier life, by optimizing the amount of hydrogen present in a gate oxide film to completely terminate dangling bonds present on the surface of the semiconductor substrate and to prevent the presence of excessive oxygen. CONSTITUTION:Heat treatment is performed after the formation of desired elements on a silicon substrate 1 and before the formation of a silicon nitride film 21 as a protective film. The heat treatment is performed at a temperature between 350-450 deg.C inclusive for a period between 10-130min inclusive. A mixed gas, composed of hydrogen and nitrogen, is used as an atmospheric gas with the hydrogen content between 5-20vol% inclusive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having improved electric characteristics and hot carrier resistance.

[0002]

2. Description of the Related Art Conventionally, the gate length of a semiconductor device has become shorter with the miniaturization and higher integration of the semiconductor device. When the gate length becomes short, the electric field of the gate at the time of writing becomes extremely high even with the same writing voltage, carriers passing therethrough obtain high energy, and collision ionization occurs. This is called the hot carrier phenomenon, and M
The characteristic deterioration of an OS (Metal Oxide Semiconductor) transistor was caused.

Therefore, "IEEE Trans. Electron Device
s ED VOL.27, No.8, p1359 ~ 1376 (August 1980); I E E E, Transaction Electronic Devices by E D, Volume 27, No. 8,
1359-1376 (August 1980) ”introduces a MOS transistor having an LDD structure that suppresses the hot carrier phenomenon by weakening the electric field in the depletion layer at the ends of the source and drain regions. Has been done.

A MOS transistor having this LDD structure is formed by the following method. After forming a gate electrode on a silicon substrate (semiconductor substrate) via a gate oxide film, a low concentration impurity is ion-implanted into the silicon substrate using the gate electrode as a mask to form a source region and a drain region under the gate electrode. Then, a low concentration impurity diffusion layer is formed.

Next, after forming a sidewall on the side surface of the gate electrode, a thermal oxide film is formed on the entire surface as a silicon oxide film for ion implantation for forming a high concentration impurity diffusion layer. Next, this thermal oxide film is used as a silicon oxide film for ion implantation of high-concentration impurities to be selectively injected into the source region and the drain region later, and high-concentration impurities are added to the silicon substrate using the gate electrode and the sidewall as a mask. Ions are implanted to form a high-concentration impurity diffusion layer in the source region and the drain region under the gate electrode.

Next, after forming a silicon oxide film on the entire surface, BPSG (Boron Phospharus Silicate Glas) is further formed.
s) film is formed and reflowed in nitrogen gas at 900 ° C. for planarization, and then SOG (Spin on Glass) is formed on the entire surface.
) Form a film. Next, after etching back the entire surface, a contact hole is opened at a desired position, a wiring material film is sputtered to fill the contact hole, and a metal wiring film is formed.

Next, the metal wiring film is patterned, a PSG film (Phosho Silicate Glass; a silicon oxide film containing phosphorus) is formed on the entire surface by a CVD method, and then a final protective film made of a silicon nitride film is formed. Thus, the MOS type semiconductor device is completed. The semiconductor device including the MOS transistor having the LDD structure has a structure in which a low-concentration impurity diffusion layer is formed at the end of the source region and the end of the drain region. The low-concentration impurity diffusion layer has the advantage that the electric field in this portion is weakened, hot carrier injection is suppressed, and the device life is improved.

[0008]

However, the above-mentioned M
When the amount of hydrogen existing in the gate oxide film is small, the OS type semiconductor device completely terminates dangling bonds (unbonded bonds) existing on the surface of the semiconductor substrate (interface between the semiconductor substrate and the gate oxide film). However, there is a problem that electrons are trapped in the unterminated dangling bond during the operation of the transistor and the threshold voltage varies.

On the other hand, if the amount of hydrogen present in the gate oxide film is too large, excess hydrogen remains in the gate oxide film even after the dangling bonds present on the surface of the semiconductor substrate are completely terminated by hydrogen. Will end up. Then, the residual hydrogen reacts with carriers having high energy generated during the operation of the transistor to increase the interface state in the semiconductor substrate, which reduces the hot carrier life (hot carrier resistance). there were.

In particular, when a plasma-silicon nitride film is formed on the uppermost layer of the protective film, a large amount of hydrogen existing in the plasma-silicon nitride film is supplied to the gate oxide film, and this excess hydrogen is supplied. It has been reported in the IEEE ED vol.28 p that the hydrogen in the hydrogen reacts with carriers with high energy generated during the operation of the transistor to increase the interface state in the semiconductor substrate and reduce the hot carrier lifetime.
83-94 (1918); I.E.E.E., E.D., Vol. 28, pp. 83-94 (1981)] by Fair and Sun.

An object of the present invention is to solve such a conventional problem, and to make the amount of hydrogen existing in the gate oxide film an optimum value, the semiconductor substrate and the gate oxide film are To provide a method for manufacturing a semiconductor device which completely terminates a dangling bond existing at the interface with and prevents excess hydrogen from existing, has excellent electric characteristics, and has an improved hot carrier life. With the goal.

[0012]

In order to achieve this object, the present invention provides a method for manufacturing a semiconductor device in which the uppermost layer of a protective film is a silicon nitride film, in which an atmosphere before forming the silicon nitride film is used. A mixture of hydrogen and nitrogen as a gas, containing 5% by volume or more of hydrogen (ie, less than 95% by volume of nitrogen) and 20% by volume or less of hydrogen (ie, more than 80% by volume of nitrogen). Provided is a method for manufacturing a semiconductor device, which comprises performing heat treatment for 10 minutes or more and 130 minutes or less at a temperature of 350 ° C. or higher and 450 ° C. or lower using gas.

[0013]

In the method for manufacturing a semiconductor device according to the present invention, hydrogen and nitrogen are used as the atmosphere gas before forming the silicon nitride film, and the hydrogen is contained in an amount of 5% by volume or more (that is, 95% by volume of nitrogen). Heat treatment for 10 minutes or more and 130 minutes or less at a temperature of 350 ° C. or more and 450 ° C. or less using a mixed gas containing hydrogen in an amount of 20% by volume or less (that is, nitrogen exceeds 80% by volume). Therefore, the dangling bonds existing at the interface between the semiconductor substrate and the gate oxide film are completely terminated together with the hydrogen contained in the silicon nitride film as the uppermost layer of the protective film formed later. At the same time, the existence of excess hydrogen in the gate oxide film is prevented.

Further, after terminating all the dangling bonds and adjusting the amount of hydrogen existing in the gate oxide film, a silicon nitride film is formed as a protective film. Prevent intrusion.
Therefore, the relationship between the dangling bond and hydrogen is
Hold semi-permanently. The critical significance of the numerical values will be described below. "The hydrogen content of the atmosphere gas is 5% by volume or more and 20% by volume or less" When the hydrogen content of the atmosphere gas is less than 5% by volume, dangling bonds existing on the surface of the semiconductor substrate are completely terminated by hydrogen. Therefore, during operation of the transistor, electrons are trapped in the dangling bond that is not terminated, the threshold voltage varies, and the transconductance (Gm) decreases. For this reason,
The electrical characteristics of the semiconductor device deteriorate.

On the other hand, the hydrogen content of the atmosphere gas is 20.
If the volume% is exceeded, unnecessary (excess) hydrogen exists in the gate oxide film after the dangling bond existing on the semiconductor substrate surface is completely terminated by hydrogen, and this hydrogen is generated during the operation of the transistor. Reacts with carriers having high energy to increase the interface state in the semiconductor substrate and shorten the hot carrier life.

When the hydrogen content of the atmosphere gas is 5% by volume or more and 20% by volume or less, the dangling bond existing on the surface of the semiconductor substrate is formed in the silicon nitride film as the uppermost layer of the protective film formed thereafter. Is completely terminated together with the hydrogen contained in the gate oxide, and excess hydrogen is prevented from entering the gate oxide film. Therefore, the hydrogen concentration of the atmosphere gas is limited to 5% by volume or more (nitrogen concentration is less than 95% by volume) and the hydrogen concentration of the atmosphere gas is limited to 20% by volume or less (nitrogen concentration exceeds 80% by volume). did. “Heat treatment temperature is 350 ° C. or higher and 450 ° C. or lower” When the heat treatment temperature is lower than 350 ° C., dangling bonds existing on the surface of the semiconductor substrate are combined with hydrogen supplied from the silicon nitride film of the protective film. Cannot be completely terminated, and electrons are trapped in the unterminated dangling bonds during the operation of the transistor, the threshold voltage varies, and the transconductance (Gm)
Will decrease. Therefore, the electrical characteristics of the semiconductor device deteriorate.

On the other hand, when the heat treatment temperature exceeds 450 ° C., stress migration causes voids in the wiring, resulting in disconnection. Therefore, the temperature cannot be higher than 450 ° C. Heat treatment temperature is 350 ° C or higher, 4
When the temperature is 50 ° C. or lower, dangling bonds existing on the surface of the semiconductor substrate are completely terminated by hydrogen, and excess hydrogen is prevented from existing in the gate oxide film.
Further, no wire disconnection due to stress migration occurs.

Therefore, the temperature of the heat treatment is limited to the range of 350 ° C. or higher and 450 ° C. or lower. "Heat treatment time is 10 minutes or more and 130 minutes or less" If the heat treatment time is less than 10 minutes, dangling bonds existing on the surface of the semiconductor substrate cannot be completely terminated by hydrogen, and the transistor is not activated during operation. Electrons are trapped in the dangling bonds that are not terminated, the threshold voltage varies, and the mutual conductance (Gm) decreases. Therefore, the electrical characteristics of the semiconductor device deteriorate. Also, it becomes difficult to control the time of heat treatment,
Not practical.

On the other hand, if the heat treatment time exceeds 130 minutes, unnecessary (excessive) hydrogen exists in the gate oxide film after the dangling bonds existing on the surface of the semiconductor substrate are completely terminated by hydrogen. Hydrogen reacts with carriers having high energy generated during the operation of the transistor to increase the interface state in the semiconductor substrate and reduce the hot carrier life. Further, the heat treatment time is too long, resulting in a significant decrease in productivity.

If the heat treatment time is 10 minutes or more and 130 minutes or less, dangling bonds existing on the surface of the semiconductor substrate may be completely terminated by hydrogen, and excess hydrogen may be present in the gate oxide film. To be prevented. Therefore, the heat treatment time is limited to a range of 10 minutes or more and 130 minutes or less.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to the drawings. 1 to 8 are partial cross-sectional views showing a part of a manufacturing process of a semiconductor device according to an embodiment of the present invention. In the step shown in FIG. 1, the p-type silicon substrate 1 is oxidized to form a silicon oxide film having a thickness of about 500 Å, and a silicon nitride film is formed thereon by a CVD method.

Next, the silicon nitride film is etched to form an n-type MOS transistor.
A p-well 2 is formed by implanting boron (B) in a dose amount of about 10 ¹³ cm ^-2 . Next, the p-type silicon substrate 1
Is subjected to heat treatment to diffuse B and expand the p well 2 region.

Next, the silicon oxide film is etched to form a pad oxide film, and then a silicon nitride film is formed thereon by a CVD method. Next, the silicon nitride film formed in the region other than the element active region (transistor formation region) is selectively removed. Next, channel stopper ions are selectively ion-implanted into the inactive region of the p-type silicon substrate 1 to form the channel stopper 3.

Next, the p-type silicon substrate 1 is thermally oxidized using the silicon nitride film formed on the device activation region as a mask to form a field oxide film 4 having a thickness of about 6000 Å in the inactive region. Then, the elements are separated. Then, the silicon nitride film is removed. Then, in the step shown in FIG. 2, the p-type silicon substrate 1 obtained in the step shown in FIG.
In the channel region of, boron fluoride (B
F ₂ ) is ion-implanted with a dose amount of about 3.3 × 10 ¹² cm ⁻² . Next, after removing the pad oxide film, the gate oxide film 5 is formed on the p-type silicon substrate 1.

Next, a polycrystalline silicon film 6 is formed on the gate oxide film 5 as a gate electrode forming material by the CVD method. Next, the polycrystalline silicon film 6 is doped with P to reduce the resistance of the polycrystalline silicon film 6. Next, in the step shown in FIG. 3, the polycrystalline silicon film 6 obtained in the step shown in FIG. 2 is selectively etched to form a gate electrode 7.

Then, using the gate electrode 7 as a mask, p
Ion implantation of P with a dose of about 2.0 × 10 ¹³ cm ^{−2 is performed on} the entire surface of the well 2 to form the n ⁻ diffusion layer 10 and the n ⁻ diffusion layer 11. Then, in the step shown in FIG.
The gate oxide film 5 is etched using the gate electrode 7 obtained in the step (1) as a mask to expose the source region and the drain region of the p-type silicon substrate 1.

Next, after a silicon oxide film is formed on the entire surface by the CVD method, the n ^- diffusion layer 10 and the n ^- diffusion layer 11 are formed.
The silicon oxide film is etched back until the surface of the p-type silicon substrate 1 corresponding to is exposed, and the sidewall 8 is formed on the side surface of the gate electrode 7. Next, in a step shown in FIG. 5, a silicon oxide film 9 for impurity ion implantation for forming a high-concentration impurity diffusion layer to be performed later is formed on the entire surface of the wafer obtained in the step shown in FIG.

Next, in the step shown in FIG. 6, the silicon oxide film 9 obtained in the step shown in FIG. 5 is used to form a high-concentration impurity diffusion layer (in this embodiment, referred to as "n ⁺ diffusion layer"). Of silicon oxide film for ion implantation, the silicon oxide film 9 is interposed, and the gate electrode 7 and the sidewall 8 are formed.
Is used as a mask to cover the entire surface of the p-well 2 by 3 × 10 ¹⁵ cm
Ion-implant arsenic (As) with a dose of about ^-2 .

In this way, the n ⁺ diffusion layers 12 and 14 are formed in the p well 2, and the source 13, the n ⁻ diffusion layer 11 and the n ⁺ diffusion layer composed of the n ⁻ diffusion layer 10 and the n ⁺ diffusion layer 12 are formed. A drain 15 of 14 was formed. Next, FIG.
In the step shown in (1), the silicon oxide film 16 is formed on the silicon oxide film 9 at a low temperature.

Then, on the silicon oxide film 16, BPS is applied.
After forming the G film 17, heat treatment is performed at 900 ° C. for 15 minutes to planarize the BPSG film 17. Next, BPSG
The film 17, the silicon oxide film 16, and the silicon oxide film 9 are selectively etched to form contact holes 1 for the transistor.
Open 8 Then, in a step shown in FIG. 8, an aluminum (Al) alloy is embedded in the contact holes 18 by sputtering on the entire surface of the wafer obtained in the step shown in FIG. 7, and metal wiring made of an aluminum (Al) alloy is formed. Form a film.

Next, after patterning the metal wiring film to form the wiring 19, P is formed on the entire surface by the CVD method.
The SG film 20 is formed. Next, the wafer on which the PSG film 20 is formed is made of hydrogen and nitrogen as an atmosphere gas, and contains 5% by volume or more of hydrogen (that is, nitrogen is 95
(Less than volume%) and a mixed gas containing hydrogen in an amount of 20 volume% or less (that is, nitrogen exceeds 80 volume%) at a temperature of 350 ° C. or higher and 450 ° C. or lower for 10 minutes or more and 130 minutes. The following heat treatment is performed.

By this process, all of the dangling bonds existing at the interface between the p well 2 and the gate oxide film 5 due to the hydrogen supplied and the hydrogen supplied from the silicon nitride film formed on the uppermost layer. Is completely terminated. Therefore, excellent transconductance (Gm) can be obtained, and a stable threshold voltage can be obtained. Also,
It is possible to prevent excess hydrogen from existing in the gate oxide film 5 after all the dangling bonds are terminated. Therefore, the conventional problem that the remaining excess hydrogen reacts with the carriers having high energy generated during the operation of the transistor to increase the interface state in the semiconductor substrate does not occur. Therefore, the hot carrier life can be improved.

Then, after finishing this heat treatment, PSG
A silicon nitride film 21 is formed on the film 20. Next, the silicon nitride film 21 is etched to adjust the film thickness to form a passivation film 22 having a predetermined film thickness including the PSG film 20 and the silicon nitride film 21. In this way, a semiconductor device including an n-type MOS transistor having an LDD structure was obtained.

Although the semiconductor device having the n-type MOS transistor having the LDD structure is manufactured in this embodiment, the present invention is not limited to this, and the present invention is also applied to a normal MOS transistor having no LDD structure. Of course, it is possible. Further, it is needless to say that the present invention can be applied to a p-type MOS transistor regardless of the n-type MOS transistor. At this time, p-type impurities such as B may be ion-implanted.

Further, according to the present invention, an n-type MO is formed on the same substrate.
It is needless to say that the present invention can be applied to a complementary MOS transistor having an S transistor and a p-type MOS transistor, and a semiconductor device having another structure. Further, in this embodiment, as impurities in the process shown in FIG.
Although P is ion-implanted, it is not limited to this, and other n such as As
Type impurities may be ion-implanted.

In this embodiment, As was ion-implanted as an impurity in the step shown in FIG. 6, but the present invention is not limited to this, and other n-type impurities such as P may be ion-implanted.
In addition, in this embodiment, PSG is performed in the process shown in FIG.
Although the passivation film 22 having a two-layer structure including the film 20 and the silicon nitride film 21 is formed, the passivation film 22 is not limited to this, and if the silicon nitride film 21 is formed on the uppermost layer, three or more layers are formed. The structure may be. If desired, the silicon nitride film 21 may be used alone.

Further, the present embodiment is one embodiment, and the ion implantation amount and energy amount at the time of ion implantation of impurities, the size of various elements, etc. are not limited to this. Next, in the same process as in the above embodiment, the heat treatment temperature was set to 350 ° C. in the process shown in FIG. 8, and the hydrogen concentration (volume%) of the atmosphere gas for the heat treatment at this temperature was changed.
The heat treatment was performed under the conditions shown in Table 1. A semiconductor device having a gate length of 0.5 μm and a gate width of 15 μm was manufactured.

Next, the hot carrier life of the semiconductor device subjected to this heat treatment was investigated by the following method. Each semiconductor device manufactured by various heat treatments has a DC
After applying the stress for a certain period of time, the mutual conductance (Gm) is measured at Vd = 0.1V and the maximum value thereof is obtained. The maximum value of Gm becomes 90% of the value at no load. The hot carrier life was calculated by measuring the DC stress application time.

Next, the hot carrier lifetime at the actual operating voltage of 3.6 V was calculated from the relationship between the hot carrier lifetime at each DC stress voltage and the reciprocal of the DC stress voltage. The results are shown in Table 1. The symbol "x" in the table indicates that the transistor did not operate normally.

[0040]

[Table 1]

From Table 1, the heat treatment temperature is 350 ° C. and the hydrogen content (volume%) is 5 vol% or more and 20 vol% or less.
The semiconductor device (semiconductor device according to the present invention) that has been subjected to heat treatment for 10 minutes or less has a hot carrier life of 10 years or more,
It was confirmed that it could withstand practical use. Here, it is known that a hot carrier life of 10 years or more is required to withstand actual use.

This is because the dangling bond existing on the surface of the p-type silicon substrate 1 is completely terminated by hydrogen according to the present invention, and after this termination, excess water enters the gate oxide film 5 from the outside. Is prevented. On the other hand, when the hydrogen content (volume%) of the atmosphere gas is less than 5 volume%, the heat treatment time is 10 minutes or longer and 130
It was confirmed that the transistor did not operate normally even if the following conditions were satisfied.

This means that the dangling bond existing on the surface of the p-type silicon substrate 1 cannot be completely terminated by hydrogen, and electrons are trapped in the unterminated dangling bond during the operation of the transistor. This is because the threshold voltage varies. Next, in the same process as in the above embodiment, the heat treatment temperature was set to 450 ° C. in the process shown in FIG. 8, and the hydrogen concentration (volume%) of the atmosphere gas and the heat treatment time at this temperature were calculated as follows. The condition shown in 1 was used. A semiconductor device having a gate length of 0.5 μm and a gate width of 15 μm was manufactured.

Next, the hot carrier life of the semiconductor device subjected to this heat treatment was investigated by the same method as described above. The results are shown in Table 2.

[0045]

[Table 2]

From Table 2, the heat treatment temperature is 450 ° C. and the hydrogen content (volume%) is 5 vol% or more and 20 vol% or less.
The semiconductor device (the semiconductor device according to the present invention) that has been subjected to the heat treatment for less than or equal to the heat treatment temperature has a heat treatment temperature of 350 ° C. (see Table 1).
It was confirmed that the hot carrier life was 10 years or more, which is sufficient for actual use, although the hot carrier life was slightly shortened compared to the result (1).

Also in this case, the dangling bond existing on the surface of the p-type silicon substrate 1 is completely terminated by hydrogen,
This is because after this termination, excess water was prevented from entering the gate oxide film 5 from the outside and becoming hydrogen.
On the other hand, the hydrogen content (volume%) of the atmosphere gas is 5 volume%.
It was confirmed that the transistor did not operate normally even if the heat treatment time was 10 minutes or more and 130 minutes or less when it was less than 1.

Also in this case, the dangling bond existing at the interface between the p-well 2 and the gate oxide film 5 cannot be completely terminated by hydrogen, and the dangling bond which is not terminated during the operation of the transistor. This is because the electrons are trapped in and the threshold voltage varies. Next, in a step similar to the above-mentioned embodiment, in the step shown in FIG.
The heat treatment was performed at a temperature of 300 ° C., and the hydrogen concentration (volume%) of the atmosphere gas and the heat treatment time at this temperature were set under the conditions shown in Table 1. Gate length = 0.5μ
m, and a gate width = 15 μm, a semiconductor device was manufactured.

Next, the hot carrier life of the semiconductor device subjected to this heat treatment was investigated by the same method as described above. The results are shown in Table 3.

[0050]

[Table 3]

From Table 3, in the semiconductor device heat-treated at 300 ° C., the hydrogen concentration of the atmosphere gas is 5 vol% or more and 20 vol% or less, and the heat treatment time is 10 minutes or more and 13 min.
It was confirmed that the transistor did not operate normally even if the condition of 0 minutes or less was satisfied. This is because if the heat treatment temperature is lower than necessary, the dangling bonds existing at the interface between the p-well 2 and the gate oxide film 5 cannot be completely terminated by hydrogen, and this termination occurs during the operation of the transistor. This is because electrons are trapped in the dangling bonds that are not present, the threshold voltage increases, and normal operation is lost.

Next, in the same process as in the above embodiment, the heat treatment temperature is set to 500 ° C. in the process shown in FIG. 8, and the hydrogen concentration (volume%) of the atmosphere gas for the heat treatment at this temperature is increased.
The heat treatment was performed under the conditions shown in Table 1. A semiconductor device having a gate length of 0.5 μm and a gate width of 15 μm was manufactured. Next, Table 4 shows the result of the semiconductor device subjected to this heat treatment.

[0053]

[Table 4]

From Table 4, it was confirmed that in the semiconductor device heat-treated at 500 ° C., the wiring was broken and the transistor did not operate normally. This is because when the heat treatment temperature is higher than necessary, voids are generated due to stress migration. As described above, from the results of Tables 1 to 4, in order to manufacture a semiconductor device having a long hot carrier life of 10 years or more and excellent electrical characteristics, an atmosphere gas is used before forming the silicon nitride film 21. Consists of hydrogen and nitrogen and contains 5% by volume of the hydrogen.
Above, using the mixed gas contained in the range of 20% by volume or less, 3
At a temperature of 50 ° C or higher and 450 ° C or lower, 10 minutes or longer, 13
It has proved necessary to carry out a heat treatment of 0 minutes or less.

[0055]

As described above, according to the method of manufacturing a semiconductor device of the present invention, before forming the silicon nitride film, the atmosphere gas is composed of hydrogen and nitrogen and contains 5% by volume or more of the hydrogen. , At a temperature of 350 ° C. or higher and 450 ° C. or lower, 1
Since the heat treatment is performed for 0 minutes or more and 130 minutes or less, all dangling bonds existing on the surface of the semiconductor substrate can be completely terminated together with hydrogen contained in the silicon nitride film as the uppermost layer of the protective film. . Therefore, excellent transconductance can be obtained, and a stable threshold voltage can be obtained.

Furthermore, after terminating all the dangling bonds, a silicon nitride film is formed as a protective film, so that the silicon nitride film is decomposed into water to prevent the intrusion of water from the outside. Does not increase.
Therefore, the relationship between the dangling bond and hydrogen is
It can be held semi-permanently. As a result, it is possible to provide a semiconductor device having excellent electrical characteristics and having an improved hot carrier life.

[Brief description of drawings]

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

FIG. 2 is a partial cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

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

FIG. 4 is a partial sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

FIG. 5 is a partial sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

FIG. 6 is a partial sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

FIG. 7 is a partial sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

FIG. 8 is a partial cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention.

[Explanation of symbols]

1 silicon substrate 2 p well 3 channel stopper 4 field oxide film 5 gate oxide film 6 polycrystalline silicon film 7 gate electrode 8 sidewall 9 silicon oxide film 10 n ^- diffusion layer 11 n ^- diffusion layer 12 n ⁺ diffusion layer 13 source 14 n ⁺ diffusion layer 15 drain 16 silicon oxide film 17 BPSG film 18 contact hole 19 wiring 20 PSG film 21 silicon nitride film 22 passivation film

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device in which the uppermost layer of a protective film is made of a silicon nitride film, wherein, before forming the silicon nitride film, the atmosphere gas is made of hydrogen and nitrogen and contains 5% by volume or more of the hydrogen. ,
Using mixed gas containing 20 volume% or less, 350 ° C.
As described above, the method for manufacturing a semiconductor device is characterized by performing heat treatment for 10 minutes or more and 130 minutes or less at a temperature of 450 ° C. or less.