JPH11163133A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor device wherein a contact hole can be formed, without lowering the element isolation functionality of an isolation insulating film formed in the groove for element isolation. SOLUTION: This semiconductor device is provided with an isolated insulating film 6b embedded in an element isolating groove 5 formed in a prescribed substrate 1, an interlayer insulating film 15 formed on the semiconductor substrate 1, and a contact hole 17, reaching the semiconductor substrate 1, formed on the interlayer insulating film 15. At this time, a dummy wiring film 13 is provided on the isolated insulating film 6 as a protective film having the characteristic of the low etching rate lower than the etching rate of the interlayer insulating film 15, which is formed when the contact hole is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device capable of forming a contact hole without deteriorating the isolation characteristics of a buried isolation insulating film and a method of manufacturing the semiconductor device.

[0002]

2. Description of the Related Art FIGS. 18 and 19 are sectional views showing a conventional method of manufacturing a semiconductor device. A conventional method for manufacturing a semiconductor device will be described with reference to the drawings. First, a first silicon oxide film 2 and a polycrystalline silicon film 3 are sequentially formed on a semiconductor substrate 1. Then, a resist is applied on the polycrystalline silicon film 3 and patterned to form a first resist film 4 (FIG. 18A).

Next, using the first resist film 4 as a mask, the polycrystalline silicon film 3, the first silicon oxide film 2 and the semiconductor substrate 1 are etched to form a groove 5 (FIG. 18B). . Next, the resist film 4 is removed, a second silicon oxide film 6 is formed by, for example, a vapor growth method, and the groove 5 is formed.
Is embedded (FIG. 18C). Next, the second silicon oxide film 6 is etched back to the upper surface of the polycrystalline silicon film 3,
The second silicon oxide film 6a is flattened (FIG. 18)
(D)).

Next, the polycrystalline silicon film 3 is removed by isotropic etching. Next, the first silicon oxide film 2 is removed by etch back to form an isolation insulating film 6b embedded in the trench 5 (FIG. 19A). Next, an interlayer insulating film 7 made of a silicon oxide film is formed. Then, a resist is applied on the interlayer insulating film 7 and patterned to form a second resist film 8 (FIG. 19B). Next, using the second resist film 8 as a mask, the interlayer insulating film 7 is formed.
Is etched down to the upper surface of the semiconductor substrate 1 to form a contact hole 9 (FIG. 19C).

[0005]

Since the conventional semiconductor device is configured as described above, the margin for mask alignment is reduced with the miniaturization of the semiconductor device, and misalignment of the second resist film 8 occurs. It is more likely to occur. In such a case, as shown in FIG.
The pattern of the resist film 8 is applied to the isolation insulating film 6b,
In this state, the interlayer insulating film 7 is etched.

[0008] Then, as shown in FIG. 20B, in the over-etching step accompanying the formation of the contact hole 10, the isolation insulating film 6b is etched, and a shaved isolation insulating film 6c is formed. . in this way,
If the isolation insulating film 6c in the groove 5 is scraped, there is a problem that the function as element isolation is reduced and electrical characteristics are deteriorated.

[0007] The term “overetching” as used herein means that a conductive film is formed through the contact hole 10 in the next step. Therefore, it is essential that the upper surface of the semiconductor substrate 1 be reliably exposed at the bottom of the contact hole 10. is there.
Since the thick interlayer insulating film 7 is etched, variations occur in the etching, and it is necessary to set the over-etching amount to a relatively large amount. Conventionally, the above-mentioned portions are as shown in FIG. Isolation insulating film 6
Most of b was etched away.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor device and a semiconductor device in which a contact hole can be formed without deteriorating the element isolation function of an isolation insulating film in a groove. It is intended to provide a manufacturing method.

[0009]

Means for Solving the Problems Claim 1 according to the present invention.
The semiconductor device includes an isolation insulating film formed by burying an element isolation groove formed in a predetermined region of the semiconductor substrate, an interlayer insulating film formed on the semiconductor substrate, and a semiconductor substrate formed on the interlayer insulating film. Semiconductor device having a contact hole formed by opening up to a thickness of, provided on a separation insulating film, a protective film having a characteristic that an etching rate is lower than an etching rate of an interlayer insulating film when a contact hole is formed. It is.

According to a second aspect of the present invention, in the semiconductor device according to the first aspect, the protective film is formed of a dummy wiring film that is electrically separated from the wiring film formed on the semiconductor substrate. It is a thing.

According to a third aspect of the present invention, there is provided the semiconductor device according to the first aspect, wherein the protective film is a dummy wiring film in which the protective film is electrically separated from the wiring film formed on the semiconductor substrate. And dummy sidewalls formed on the side walls of the dummy wiring film.

According to a fourth aspect of the present invention, in the semiconductor device according to the third aspect, the dummy sidewall is formed of a nitride film, and the interlayer insulating film is formed of an oxide film.

According to a fifth aspect of the present invention, in the semiconductor device according to the first aspect, the protective film is formed of a nitride film covering an upper surface of the isolation insulating film, and the interlayer insulating film is formed of an oxide film. Things.

According to a sixth aspect of the present invention, in the semiconductor device according to the fifth aspect, the isolation insulating film is formed of an oxide film.

According to a seventh aspect of the present invention, in the semiconductor device according to the fifth aspect, the protective film is formed so as to cover only the upper surface of the isolation insulating film.

According to another aspect of the present invention, there is provided a semiconductor device, comprising: an isolation insulating film formed by burying an element isolation groove formed in a predetermined region of a semiconductor substrate; In a semiconductor device having an interlayer insulating film formed and a contact hole formed in the interlayer insulating film so as to reach the semiconductor substrate, the isolation insulating film has an etching rate higher than an etching rate of the interlayer insulating film when the contact hole is formed. It is formed of a film having low characteristics.

According to a ninth aspect of the present invention, in the semiconductor device according to the eighth aspect, the isolation insulating film is formed of an oxide film, and the interlayer insulating film is formed of a nitride film or an oxide film containing boron or phosphorus. It is formed by the method.

According to a tenth aspect of the present invention, in the semiconductor device according to the eighth aspect, the isolation insulating film is formed of either a thermal oxide film or a nitride film, and the interlayer insulating film is formed of an oxide film or boron or phosphorus. Is formed of any of the oxide films containing.

According to a twelfth aspect of the present invention, in the semiconductor device of the ninth aspect, when the isolation insulating film is formed of a nitride film, the semiconductor device may be provided between the isolation insulating film and the semiconductor substrate. This is one in which a base film is interposed.

According to a twelfth aspect of the present invention, in a method of manufacturing a semiconductor device, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and An interlayer insulating film is formed, a patterned resist film is formed on the interlayer insulating film, the interlayer insulating film is etched down to the upper surface of the semiconductor substrate using the resist film as a mask, a contact hole is formed, and the contact hole is exposed. The formed semiconductor substrate is thermally oxidized to form a thermal oxide film having a desired thickness, the thermal oxide film is etched by a predetermined amount, and the semiconductor substrate at the bottom of the contact hole is exposed.

According to a thirteenth aspect of the present invention, in the method of manufacturing a semiconductor device, a groove for element isolation is formed in a predetermined region of the semiconductor substrate, an isolation insulating film is formed in the groove, and An interlayer insulating film is formed, a patterned resist film is formed on the interlayer insulating film, the interlayer insulating film is etched down to the upper surface of the semiconductor substrate using the resist film as a mask, a preliminary contact hole is formed, and the interlayer insulating film is formed. A desired amount of an insulating film is formed so as to cover, an insulating film is formed on the side wall and the bottom surface of the preliminary contact hole, the insulating film is etched back, and the semiconductor substrate at the bottom of the preliminary contact hole is exposed. A contact hole in which an insulating film is formed is formed.

According to a fourteenth aspect of the present invention, in a method of manufacturing a semiconductor device, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and At the same time as forming the wiring film, a dummy wiring film electrically separated from the wiring film is formed on the isolation insulating film, an interlayer insulating film is formed on the semiconductor substrate, and a patterned resist film is formed on the interlayer insulating film. Then, using the resist film as a mask, the interlayer insulating film is etched down to the upper surface of the semiconductor substrate to form a contact hole.

According to a fifteenth aspect of the present invention, in the method for manufacturing a semiconductor device according to the fourteenth aspect, after forming the wiring film and the dummy wiring film, etching the interlayer insulating film on the side wall of the wiring film when forming the contact hole. A dummy sidewall is formed on the side wall of the dummy wiring film at the same time as forming a sidewall having a lower etching rate than the etching rate.

According to a sixteenth aspect of the present invention, in a method of manufacturing a semiconductor device, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and Forming a protective film having a lower etching rate than the etching rate of the interlayer insulating film in the post-process at the time of forming the contact hole; forming an interlayer insulating film on the protective film;
A patterned resist film is formed on the interlayer insulating film, and the resist film is used as a mask to perform first etching until the interlayer insulating film reaches the upper surface of the protective film, and performs second etching until the protective film reaches the upper surface of the semiconductor substrate. Is etched to form a contact hole.

In the method of manufacturing a semiconductor device according to a seventeenth aspect of the present invention, in the sixteenth aspect, the protective film is formed of a film having an etching rate higher than an etching rate of the isolation insulating film when forming the contact hole. It is formed.

Further, according to a method of manufacturing a semiconductor device of the present invention, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and Forming a protective film having a lower etching rate than an etching rate of an interlayer insulating film in a post-process at the time of forming a contact hole, patterning the protective film, and forming the protective film so as to remain only on the isolation insulating film; An interlayer insulating film is formed thereon, a patterned resist film is formed on the interlayer insulating film, and using the resist film as a mask,
Etch the interlayer insulating film to the top of the semiconductor substrate,
A contact hole is formed.

According to a nineteenth aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the sixteenth to eighteenth aspects, the interlayer insulating film is formed of an oxide film, and the protective film is formed of a nitride film. To form.

According to a twentieth aspect of the present invention, in the method of manufacturing a semiconductor device, the isolation insulating film is formed of an oxide film.

According to a twenty-first aspect of the present invention, in a method of manufacturing a semiconductor device, a detection film is formed on a semiconductor substrate, and an interlayer insulating film is formed so as to cover the semiconductor substrate and the detection film. Forming a patterned resist film on the interlayer insulating film, etching the interlayer insulating film to the upper surface of the semiconductor substrate using the resist film as a mask, and forming a contact hole. The etching time until reaching the upper surface of the semiconductor substrate after the detection is determined and controlled.

According to a twenty-second aspect of the present invention, in the method for manufacturing a semiconductor device according to the twenty-first aspect, the detection film is formed by forming a dummy film electrically separated from the wiring film simultaneously with the wiring film formed on the semiconductor substrate. It is formed by a wiring film.

According to a twenty-third aspect of the present invention, in a method of manufacturing a semiconductor device, an interlayer insulating film is formed on a semiconductor substrate, a patterned resist film is formed on the interlayer insulating film, and the resist film is used as a mask. In the method for manufacturing a semiconductor device, in which the interlayer insulating film is etched to reach the upper surface of the semiconductor substrate and a contact hole is formed, a current detecting portion formed by exposing the semiconductor substrate on the back side of the semiconductor substrate is formed.
The current on the exposed semiconductor substrate is measured, and it is determined from the current value of the semiconductor substrate that the etching at the time of forming the contact hole reaches the upper surface of the semiconductor substrate, thereby determining the end point of the etching.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are sectional views showing a method for manufacturing a semiconductor device according to the first embodiment of the present invention. A method for manufacturing the semiconductor device according to the first embodiment will be described with reference to the drawings. First, as in the conventional case, a first silicon oxide film 2 and a polycrystalline silicon film 3 are sequentially formed on a semiconductor substrate 1. Then, a resist is applied on the polycrystalline silicon film 3 and patterned to form a first resist film 4 (FIG. 1A).

Next, using the first resist film 4 as a mask, the polycrystalline silicon film 3, the first silicon oxide film 2 and the semiconductor substrate 1 are etched to form a groove 5 (FIG. 1B). . Next, the resist film 4 is removed, a second silicon oxide film 6 is formed by, for example, a vapor growth method, and the trench 5 is buried (FIG. 1C). Next, the second silicon oxide film 6 is etched back to the upper surface of the polycrystalline silicon film 3 and flattened to form a second silicon oxide film 6a (FIG. 1).
(D)).

Next, the polycrystalline silicon film 3 is removed by isotropic etching. Next, the first silicon oxide film 2 is removed by etch back to form an isolation insulating film 6b embedded in the trench 5 (FIG. 2A). Next, a conductive film 11 for forming, for example, a gate electrode on the semiconductor substrate 1
Are laminated (FIG. 2B). The conductive film 11 is formed of a film having an etching rate lower than an etching rate of an interlayer insulating film described later when forming a contact hole.

Next, the conductive film 11 is patterned to form the gate electrode 12, and at the same time, the conductive film 11 is patterned.
Is formed so as to remain on the upper surface of the isolation insulating film 6b to form a dummy wiring film 13 which is electrically separated from the gate electrode 12 (FIG. 2C). Next, sidewalls 14 are formed on the sidewalls of the gate electrode 12. next,
An interlayer insulating film 15 made of a silicon oxide film is formed. Then, a resist is applied on the interlayer insulating film 15 and patterned to form a second resist film 16.

Next, using the second resist film 16 as a mask, the interlayer insulating film 15 is etched down to the upper surface of the semiconductor substrate 1 to form a contact hole 17 (FIG. 2).
(D)). At this time, the etching rate of the dummy wiring film 13 on the upper surface of the isolation insulating film 6b is lower than the etching rate of the interlayer insulating film 15, and the isolation insulating film 6b existing under the dummy wiring film 13 when the interlayer insulating film 15 is etched. Are protected without being etched.

According to the semiconductor device of the first embodiment configured as described above, the protective film having the characteristic that the etching rate is lower than the etching rate of the interlayer insulating film 15 when the contact hole is formed, on the isolation insulating film 6b. Since the dummy wiring film 13 is formed, the interlayer insulating film 1 is formed.
5, the dummy wiring film 13 becomes the isolation insulating film 6b at the time of etching.
, And prevents the isolation insulating film 6b from being etched. Therefore, the second resist film 16
Even if the mask alignment is displaced, the contact hole 17 can be formed without reducing the thickness of the isolation insulating film 6b, and it is possible to prevent the electrical characteristics of the isolation insulating film 6b from deteriorating.

Since the dummy wiring film 13 is formed in the same step as the step of forming the gate electrode 12, it is not necessary to add a new step for forming the dummy wiring film 13.

In the first embodiment, the example in which the dummy wiring film 13 is formed on the entire surface of the interlayer insulating film 15 has been described. However, the present invention is not limited to this. For example, as shown in FIG. The case where the dummy wiring film 18 electrically separated from the gate electrode 12 is patterned so as to be formed on a part of the interlayer insulating film 15 will be described.

In this case, for example, a silicon nitride film 19 having an etching rate lower than the etching rate of the interlayer insulating film at the time of forming the contact hole is laminated on the semiconductor substrate 1.
By etching back, a sidewall 14 is formed on the sidewall of the gate electrode 12. Simultaneously, a dummy sidewall 20 is formed on the side wall of the dummy wiring film 18 (FIG. 3B).

Next, an interlayer insulating film 15 made of a silicon oxide film is formed. Then, a resist is applied on the interlayer insulating film 15 and patterned to form a second resist film 16. Next, using the second resist film 16 as a mask, the interlayer insulating film 15 is etched down to the upper surface of the semiconductor substrate 1 to form a contact hole 21 (FIG. 3C).

At this time, the dummy wiring film 18 and the dummy sidewalls 20 on the upper surface of the isolation insulating film 6b are hardly etched under the etching condition of the interlayer insulating film 15, and the isolation insulating film 6b existing thereunder is hardly etched. It is protected without being etched.

Further, the example in which the dummy wiring film 13 and the dummy wiring film 18 are formed simultaneously with the gate electrode 12 has been described. However, the present invention is not limited to this. May be formed,
In addition, needless to say, even if a process for forming only the dummy wiring film is provided, the same effect of protecting the isolation insulating film 6b can be obtained.

Embodiment 2 4 and 5 are sectional views showing a method for manufacturing a semiconductor device according to the second embodiment of the present invention. A method for manufacturing the semiconductor device according to the second embodiment will be described with reference to the drawings. First, a groove 5 is formed in the semiconductor substrate 1 through the same process as in the first embodiment, and the groove 5 is formed.
An isolation insulating film 6b buried therein is formed (FIG. 4).
(A)).

Next, for example, a plasma C
The nitride film 22 serving as a protective film is
Laminate to a thickness of 0-500 angstroms (Fig. 4
(B)). This protective film is formed of a material having a characteristic that the etching rate is lower than the etching rate between the interlayer insulating layers when the contact hole is formed. The thickness of the nitride film 22 is determined by the selectivity with the etching rate of the interlayer insulating film formed in a later step.

Next, an interlayer insulating film 23 made of a silicon oxide film is formed on the nitride film 22. Then, a resist is applied on the interlayer insulating film 23 and patterned to form a resist film 24 (FIG. 4C). Next, using the resist film 24 as a mask, the first etching is performed until the interlayer insulating film 23 reaches the upper surface of the nitride film 22 to form an opening 25. (FIG. 5 (a)).

At this time, as the etching condition, for example, E
When a high-density plasma such as CR is used and a gas system using a gas having a small CF ratio (a gas having a high ratio of F to C) such as C ₄ F ₈ is used, the selectivity of the nitride film 22 to the nitride film becomes 10%. Therefore, the etching rate of the nitride film 22 is lower than the etching rate of the interlayer insulating film 23,
When the interlayer insulating film 23 is etched, the isolation insulating film 6b present below the nitride film 22 is protected without being etched.

Next, using the resist film 24 as a mask, a second etching is performed until the nitride film 22 reaches the upper surface of the semiconductor substrate 1, and an opening 25 is dug down to form a contact hole 2.
6 is formed (FIG. 5B). At this time, if the etching is performed using a gas system of CH ₂ F ₂ or SF ₆ , the selectivity of the isolation insulating film 6 b made of a silicon oxide film to 3 or more can be secured. Therefore, the etching rate of the isolation insulating film 6 b made of a silicon oxide film is lower than the etching rate of the nitride film 22, and the isolation insulating film 6 b is hardly etched when the nitride film 22 is etched.

According to the semiconductor device of the second embodiment configured as described above, the nitride film having the characteristic that the etching rate is lower than the etching rate of the interlayer insulating film 23 when the contact hole is formed is formed on the isolation insulating film 6b. Since the nitride film 22 is formed, the nitride film 22 functions as a protective film when the interlayer insulating film 23 is etched, thereby preventing the isolation insulating film 6b from being etched. Therefore, the resist film 2
Even if the alignment of the mask 4 is deviated, the contact hole 26 can be formed without reducing the thickness of the isolation insulating film 6b.

When the nitride film 22 is etched, the isolation insulating film 6b is formed of a silicon oxide film having an etching rate lower than the etching rate of the nitride film 22, so that the isolation insulating film 6b is almost completely etched. Never. Therefore, even if the mask alignment of the resist film 24 is shifted, the contact hole 26 can be formed without reducing the thickness of the isolation insulating film 6b. In addition, the etching of the nitride film 22 can be dealt with only by changing the etching conditions at the time of forming the contact hole, and the number of steps due to this is not increased.

In the second embodiment, the example in which the nitride film 22 is formed over the entire surface of the semiconductor substrate 1 has been described. However, the present invention is not limited to this. For example, the same steps as those in the second embodiment are performed. After the nitride film 22 is formed on the semiconductor substrate 1 as shown in FIG. 4 (b), the nitride film 22 is patterned and formed as a protective film 27 so as to remain only on the upper surface of the isolation insulating film 6b (FIG. a)).

Next, an interlayer insulating film 28 made of a silicon oxide film is formed on the semiconductor substrate 1. Then, a resist is applied on the interlayer insulating film 28 and patterned to form a resist film 29 (FIG. 6B). Next, the resist film 2
Using the mask 9 as a mask, the interlayer insulating film 28 is etched until reaching the upper surface of the semiconductor substrate 1 to form a contact hole 30.
Is formed (FIG. 6C). At this time, the etching rate of the protective film 27 is lower than the etching rate of the interlayer insulating film 28, and when the interlayer insulating film 28 is etched,
Is protected without being etched.

With this configuration, although the number of steps for patterning the nitride film is increased, the same effect as that of the second embodiment, that is, the protection of the isolation insulating film 6b is obtained, as well as the interlayer insulating film. When forming an opening up to the semiconductor substrate 1 in another region 28, the etching conditions and the like can be set without considering the nitride film.

Embodiment 3 FIG. 7 and 8 are cross sectional views showing the structure of the method for manufacturing a semiconductor device according to the third embodiment of the present invention. A method for manufacturing the semiconductor device according to the third embodiment will be described with reference to the drawings. First, a first silicon oxide film 2 and a polycrystalline silicon film 3 are sequentially formed on a semiconductor substrate 1 through steps similar to those of the above-described embodiments.
The trench 5 is formed by etching the polycrystalline silicon film 3, the first silicon oxide film 2, and the semiconductor substrate 1 in a desired region.

Next, while the semiconductor substrate 1 is heated to, for example, about 1000 ° C., a silicon oxide film is laminated by a vapor phase growth method. Then, a thermal oxide film 31 is formed, and the groove 5 is formed.
Is embedded (FIG. 7A). The thermal oxide film 31 formed at this time is formed of a film having a lower etching rate than the etching rate of the interlayer insulating film at the time of forming a contact hole described later. Next, the thermal oxide film 31 is etched back to the upper surface of the polycrystalline silicon film 3,
The surface is planarized to form a thermal oxide film 31a (FIG. 7B).

Next, the polycrystalline silicon film 3 is removed by isotropic etching. Next, the first silicon oxide film 2 is removed by etch back, and an isolation insulating film 31b made of a thermal oxide film embedded in the trench 5 is formed (FIG. 7).
(C)). Next, for example, a boron or phosphorus compound is contained in the atmosphere when laminating TEOS to form an interlayer insulating film 3 made of an oxide film containing boron or phosphorus.
Form 2 Then, a resist is applied on the interlayer insulating film 32 and patterned to form a resist film 33 (FIG. 8A).

Next, using the resist film 33 as a mask, for example, an interlayer insulating film 3 using a gas system of C ₄ F ₈ , O ₂ and Ar
2 is etched down to the upper surface of the semiconductor substrate 1 to form a contact hole 34 (FIG. 8B). At this time, since the selectivity of the isolation insulating film 31b to the isolation insulating film 31b can be set to about 5, the etching rate of the isolation insulating film 31b is lower than the etching rate of the interlayer insulating film 32. The isolation insulating film 31b is hardly etched.

According to the semiconductor device of the third embodiment configured as described above, the isolation insulating film 31b is a film having a lower etching rate than the etching rate of the interlayer insulating film 32 when the contact hole is formed. Since the isolation insulating film 31b is formed, the isolation insulating film 31b is hardly etched when the interlayer insulating film 32 is etched. Therefore, even if the mask alignment of the resist film 33 is shifted, the contact hole 34 can be formed without reducing the thickness of the isolation insulating film 31b.

In the third embodiment, an example is shown in which the isolation insulating film 31b is formed of a thermal oxide film and the interlayer insulating film 32 is formed of a silicon oxide film. However, the present invention is not limited to this. For example, FIGS. A method as shown in FIG.
A method of manufacturing a semiconductor device according to another modification of the third embodiment will be described with reference to the drawings. First, the semiconductor substrate 1
A resist is applied thereon and patterned to form a first resist film 35 (FIG. 9A). Next, the semiconductor substrate 1 is etched using the first resist film 35 as a mask to form a groove 36 (FIG. 9B).

Next, the first resist film 35 is removed, and a nitride film 37 is laminated by, for example, a low pressure CVD method to fill the groove 36 (FIG. 9C). The nitride film 37 formed at this time is
The interlayer insulating film is formed of a film having a lower etching rate than the etching rate of the interlayer insulating film when forming a contact hole described later. Next, the nitride film 37 is etched back to the upper surface of the semiconductor substrate 1 and planarized to form an isolation insulating film 37a made of a nitride film (FIG. 9D).

Next, an interlayer insulating film 38 made of a silicon oxide film is formed. Then, a resist is applied on the interlayer insulating film 38 and patterned to form a second resist film 39 (FIG. 10A). Next, using the second resist film 39 as a mask, the interlayer insulating film 38 is etched to reach the upper surface of the semiconductor substrate 1 by using, for example, a gas system of C ₄ F ₈ , O ₂ , and Ar to form a contact hole 40. (FIG. 10
(B)). At this time, since the selectivity of the isolation insulating film 37 to the isolation insulating film 37 can be set to about 10, the etching rate of the isolation insulating film 37 is lower than the etching rate of the interlayer insulating film 38. The isolation insulating film 37 is hardly etched.

According to the semiconductor device shown in FIGS. 9 and 10 configured as described above, the same effects as those of the semiconductor device according to the third embodiment described above can be obtained. When the isolation insulating film 37 is formed of a nitride film as described above, in order to improve the adhesion between the semiconductor substrate 1 and the nitride film, for example, as shown in FIG. A base film 41 may be interposed between the film and the isolation insulating film 37.

As a method for forming the underlayer 41, the groove 3
After the formation of 6, the semiconductor substrate 1 can be formed of a thermal oxide film that can be formed by heating the semiconductor substrate 1 in an oxygen atmosphere at about 1000 ° C. and oxidizing the upper surface of the semiconductor substrate 1, for example.

As another combination of the interlayer insulating film and the isolation insulating film other than the above example, for example, a silicon oxide film is used for the isolation insulating film, and an oxide film containing boron or phosphorus is used for the interlayer insulating film. Even if a nitride film is used as the isolation insulating film and an oxide film is used as the interlayer insulating film, if the desired etching conditions are set, the etching rate of the isolation oxide film is higher than the etching rate of the interlayer insulating film when forming the contact hole. Can be set lower, so that the etching of the isolation oxide film in the etching of the interlayer insulating film can be minimized, and the same effect as in the above case can be obtained.

As described above, in each of the above embodiments, the isolation insulating film is hardly etched when forming the contact hole by protecting the isolation insulating film or changing the etching rate between the isolation insulating film and the interlayer insulating film. I explained the example of protecting. Hereinafter, other embodiments will be described.

Embodiment 4 FIG. 12 is a cross-sectional view showing a configuration of a method for manufacturing a semiconductor device according to Embodiment 4 of the present invention. A method for manufacturing the semiconductor device according to the fourth embodiment will be described with reference to the drawings. First, a groove 5 is formed in the semiconductor substrate 1 through steps similar to those of the above-described embodiments, and an isolation insulating film in which a silicon oxide film is embedded in the groove 5 is formed.

Next, an interlayer insulating film 7 made of a silicon oxide film is formed on the semiconductor substrate 1. Then, the interlayer insulating film 7
A resist is applied thereon and patterned to form a second resist film 8. Next, using the second resist film 8 as a mask, the interlayer insulating film 7 is etched down to the upper surface of the semiconductor substrate 1 to form a contact hole 10 and a contact hole 42.

When forming this contact hole, the etching rate of the interlayer insulating film 7 and the isolation insulating film 6c is the same as in the conventional case. The shaved isolation insulating film 6c is formed at the lower part of 10, and the upper surface of the semiconductor substrate 1 and the surface of the semiconductor substrate 1 on the side wall of the groove 5 are exposed. Further, since there is no isolation insulating film or the like below the contact hole 42 in other places, only the upper surface of the semiconductor substrate 1 is exposed (FIG. 12A).

Next, the second resist film 8 is removed. Next, the semiconductor substrate 1 exposed in each of the contact holes 10 and 42 is heated to 1000 ° C. in an oxygen atmosphere, for example.
The substrate is heated to a certain degree and oxidized to form a thermal oxide film 43 on the semiconductor substrate 1 (FIG. 12B). Thermal oxide film 4 at this time
3 is formed in proportion to the amount of exposure of the semiconductor substrate 1, and since the semiconductor substrate 1 is largely exposed at the portion where the isolation insulating film 6 c has been cut due to the displacement of the second resist film 8, As a result, more thermal oxide films 43 are formed as compared with the above-mentioned location.

Next, etch back is performed to etch the thermal oxide film 43 by a predetermined amount. At this time, the interlayer insulating film 7
Is also etched back as a whole, and the film is reduced to reduce the interlayer insulating film 7a.
And formed as contact holes 10a and 42a. Then, each contact hole 10a and 4
At the bottom of 2a, thermal oxide film 43 is etched by a predetermined amount, and semiconductor substrate 1 is exposed. Also,
A part of the thermal oxide film 43a remains in the portion of the isolation insulating film 6c which is removed by the displacement (FIG. 12C).

According to the semiconductor device of the fourth embodiment configured as described above, the thermal oxide film 43a is formed and remains at the portion where the isolation insulating film 6c has been cut, and the isolation insulating film 6c and the thermal oxide film The function of element isolation is performed by the film 43a. Therefore, even if the mask alignment of the second resist film 8 is shifted, the contact holes 10a and 42a can be formed without deteriorating the function of element isolation.

Embodiment 5 FIG. 13 is a cross sectional view showing a structure of a method for manufacturing a semiconductor device according to the fifth embodiment of the present invention. A method for manufacturing a semiconductor device according to the fifth embodiment will be described with reference to the drawings. First, a groove 5 is formed in the semiconductor substrate 1 through a process similar to that of each of the above embodiments, and an isolation insulating film in which a silicon oxide film is embedded in the groove 5 is formed.

Next, an interlayer insulating film 7 made of a silicon oxide film is formed on the semiconductor substrate 1. Then, the interlayer insulating film 7
A resist is applied thereon and patterned to form a patterned resist film 44 with an opening larger than a desired opening. Next, using the resist film 44 as a mask, the interlayer insulating film 7 is etched down to the upper surface of the semiconductor substrate 1 to form preliminary contact holes 45 and 46.

At the time of forming this preliminary contact hole, the etching rate of the interlayer insulating film 7 and that of the isolation insulating film 6b are the same as in the conventional case. A shaved isolation insulating film 6d is formed in the lower portion, and the upper surface of the semiconductor substrate 1 and the surface of the semiconductor substrate 1 on the side wall of the groove 5 are exposed. In addition, since no isolation insulating film or the like is present below the preliminary contact hole 46 at another location, only the upper surface of the semiconductor substrate 1 is exposed.

Next, the resist film 44 is removed. next,
Using, for example, a low pressure CVD method, which has excellent coverage,
The oxide film 47 as an insulating film is laminated to a thickness such that the shaved portion of the isolation insulating film 6d is buried, for example, about several hundred angstroms (FIG. 13B). Next, the oxide film 47 is etched back by a predetermined amount, so that each preliminary contact hole 45 is etched.
At the bottoms of and 46, oxide film 47 is etched by a predetermined amount, and semiconductor substrate 1 is exposed.

Further, a part of the oxide film 47a remains at the portion of the isolation insulating film 6d which is removed by the displacement. Oxide film 47a remains on the side walls of spare contact holes 45 and 46, and contact holes 48 and 49 remain.
Is formed (FIG. 13C). In this manner, contact holes 48 and 49 are formed with oxide film 47a remaining on the side walls of preliminary contact holes 45 and 46, and therefore have a larger diameter in advance in consideration of the thickness of oxide film 47a on the side walls. Spare contact holes 45 and 46 need to be opened.

According to the semiconductor device of the fifth embodiment configured as described above, oxide film 47a is formed and left at the portion where isolation insulating film 6d is shaved, and isolation insulating film 6c and oxide film 47a are formed. Will perform the function of element isolation. Therefore, even if the mask alignment of the resist film 44 is shifted, the contact holes 48 and 49 can be formed without deteriorating the function of element isolation.

In the above-described fourth and fifth embodiments, the invention has been described on how to bury the etched portion after the isolation insulating film is etched and shaved to prevent the element isolation function from deteriorating. A description will be given of an invention for preventing the isolation insulating film from being etched by minimizing the amount of over-etching even if an alignment shift occurs when forming a contact hole.

Embodiment 6 FIG. 14 and 15 are cross-sectional views illustrating a method for manufacturing a semiconductor device according to the sixth embodiment of the present invention. A method for manufacturing a semiconductor device according to the fifth embodiment will be described with reference to the drawings. First, the semiconductor substrate 1 is etched through steps similar to those of the above embodiments,
A groove 5 is formed.

Next, an isolation insulating film 6b made of a silicon oxide film is formed in the trench 5. Next, a conductive film 50 for forming, for example, a gate electrode is laminated on the semiconductor substrate 1 (FIG. 14).
(A)). Next, patterning is performed to form the gate electrode 51, and at the same time, patterning is performed so that the conductive film 50 remains in a portion (for example, a TEG pattern outside the chip) which is not related to the element and does not hinder the formation of the element. A detection film 52 made of a dummy wiring film electrically separated from the gate electrode 12 is formed.

At this time, it is needless to say that the larger the area of the detection film 52 is, the easier it is to detect in the subsequent detection step, and it is set so as to be formed in the widest possible range without affecting other elements. I do. Next, the gate electrode 51
A sidewall 53 is formed on the side wall of FIG.
(B)).

Next, an interlayer insulating film 54 made of a silicon oxide film is formed. Then, a resist is applied on the interlayer insulating film 54 and patterned to form a resist film 55.
At this time, the pattern of the resist film 55 is also formed at a position corresponding to the detection film 52 in addition to the pattern for forming a desired contact hole (FIG. 14).
(C)).

Next, using the resist film 55 as a mask, the interlayer insulating film 54 is etched down to the upper surface of the semiconductor substrate 1. At this time, the opening 56 up to the upper surface of the detection film 52 is formed.
Is formed, and the semiconductor substrate 1 is formed in the contact hole forming portion.
A preliminary opening 57 that does not reach the upper surface of is formed. Then, the fact that the interlayer insulating film 54 has been etched to this position can be monitored by, for example, a method of monitoring plasma emission,
Detection is performed using a method of monitoring the peak voltage of the high-frequency power applied at the time of etching (FIG. 15A).

Next, it is assumed that the etching amount up to the upper surface of the semiconductor substrate 1 after the detection of the detection film 52 is taken into consideration, for example, the film thickness of the interlayer insulating film 54 and the amount of over-etching. The time is determined and the etching of the interlayer insulating film 54 is controlled to form a contact hole 58 (FIG. 15B).

In a later step, a wiring film is buried in the contact hole 58. At this time, the wiring film is also buried in the opening 56. In this case, even if the wiring film is buried in the opening 56, no problem occurs because the detection film 52 is not electrically connected to any portion. Further, it is needless to say that the opening 56 may be entirely buried with a wiring film, and is not limited to this, and may be buried to such an extent that the step is not affected.

According to the method of manufacturing the semiconductor device of the sixth embodiment performed as described above, the interlayer insulating film 54 is etched down to the upper surface of the semiconductor substrate 1 and the contact hole 5 is formed.
In the case of forming the gate insulating film 8, it is detected that the film reaches the detection film 52, and the etching time until reaching the upper surface of the semiconductor substrate 1 after the detection is determined and controlled. Etching of the isolation insulating film 6b with little error can be minimized. Therefore, even if the mask alignment of the resist film 55 is shifted, the contact hole 58 can be formed without reducing the thickness of the isolation insulating film 6b.

Further, since the detection film 52 is formed in the same process as the gate electrode 51, it is not necessary to newly provide a process for forming the detection film 52, and the number of processes is the same as the conventional process. It can be carried out.

In the sixth embodiment, the example in which the detection film 52 is formed in the same step as that of the gate electrode 51 has been described. However, the present invention is not limited to this, and only another wiring film or only the detection film is formed. It is needless to say that the same effect as in the sixth embodiment can be obtained even if they are formed similarly in the process.

The example in which the detection film 52 is formed of a conductive film has been described. However, the present invention is not limited to this. The detection film may be a film that can be detected when the interlayer insulating film 54 is etched. Whatever film is used,
Needless to say, the same effects as in the sixth embodiment can be obtained.

Embodiment 7 FIG. 16 is a view illustrating a method of manufacturing the semiconductor device according to the seventh embodiment of the present invention. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 59 denotes an interlayer insulating film formed on the semiconductor substrate 1, reference numeral 60 denotes a contact hole formed by etching the interlayer insulating film to the upper surface of the semiconductor substrate 1, and reference numeral 61 denotes a semiconductor substrate 1 on the back side of the semiconductor substrate 1. A current detector 62 formed by being exposed is a current detector for detecting the current value of the semiconductor substrate 1 of the current detector 61, and the current attached to the exposed surface of the semiconductor substrate 1 of the current detector 61. 63 comprising a detection sensor 62a and a current detection circuit connected to the current detection sensor 62a.
Denotes a stage on which the semiconductor substrate 1 is placed.

FIG. 17 is a sectional view showing a method of forming the current detecting portion 61. A method for forming the current detection unit 61 will be described with reference to the drawings. First, a patterned resist film 64 is formed on the interlayer insulating film 59 formed on the back surface side of the semiconductor substrate 1 (FIG. 17A). Next, using the resist film 64 as a mask, the interlayer insulating film 59 is etched down to the upper surface of the semiconductor substrate 1, an opening 65 is formed, and a current detecting portion 61 in which the semiconductor substrate 1 is exposed is formed (FIG. 17 ( b)). Next, the resist film 64 is removed (FIG. 1).
7 (c)).

A method for manufacturing a semiconductor device according to the seventh embodiment will be described with reference to the drawings. First, before the interlayer insulating film 59 is formed on the upper surface of the semiconductor substrate 1 and the contact hole is formed, the current detecting unit 61 is formed in advance on the back surface of the semiconductor substrate 1 by the above-described process. Next, the semiconductor substrate 1
Is placed on a stage, and the interlayer insulating film 59 is placed on the semiconductor substrate 1.
Etching to the top surface of the contact hole 60
To form In this step, the current on the semiconductor substrate 1 exposed by the current detector 61 is measured by the current detector 62 in advance.

Then, when the ions generated during the etching reach the upper surface of the semiconductor substrate 1, they are incident on the semiconductor substrate 1, and a current flows on the semiconductor substrate 1 due to this phenomenon. Therefore, by detecting the current value on the semiconductor substrate 1, it can be determined whether or not the etching has reached the upper surface of the semiconductor substrate 1. As a method of setting this determination, for example, a method of providing a specified value for a change amount between a current value before starting etching and a current value at the time of etching, and a method of setting a current value before starting etching and a current value at the time of etching. A method of providing a specified value for the change rate may be considered.

When the contact hole 60 actually reaches the upper surface of the semiconductor substrate 1, the current value measured on the upper surface of the semiconductor substrate 1 is assumed to be about 0.1 to 10 mA. The end point of the etching is determined by the current value thus determined, and the contact hole 60 is formed.

According to the semiconductor device manufacturing method of the seventh embodiment performed as described above, the current value on the back surface of the semiconductor substrate 1 is measured, and the etching end point is determined based on the measured current value. In addition, there is almost no etching error in the interlayer insulating film 59, and it is possible to minimize the etching of, for example, the isolation insulating film and the like existing therebelow. Therefore, even if the mask alignment of the resist film for forming the contact hole is shifted, the contact hole 60 can be formed without reducing the thickness of the isolation insulating film and the like.

Further, in the seventh embodiment, an example has been shown in which an opening is formed in the interlayer insulating film 59 formed on the back surface side of the semiconductor substrate 1 to constitute a current detecting section. However, the present invention is not limited to this. In addition, if the current detection unit capable of measuring the current value on the semiconductor substrate 1 by exposing the upper surface of the semiconductor substrate 1 can be secured, it goes without saying that the same effect as in the seventh embodiment can be obtained.

[0097]

As described above, according to the first aspect of the present invention, an isolation insulating film formed by burying an element isolation groove formed in a predetermined region of a semiconductor substrate, In a semiconductor device having an interlayer insulating film formed on a substrate and a contact hole formed in the interlayer insulating film to reach the semiconductor substrate, the interlayer insulating film is etched on the isolation insulating film when the contact hole is formed. Since a protective film having a lower etching rate than the etching rate is provided, the isolation insulating film is protected by the protective film, so that a contact hole can be formed without deteriorating the element isolation function of the isolation insulating film. There is an effect that a device can be provided.

According to a second aspect of the present invention, in the first aspect, the protective film is formed by the dummy wiring film which is electrically separated from the wiring film formed on the semiconductor substrate. In addition, it is possible to provide a semiconductor device in which a protective film can be formed simultaneously with another wiring film.

According to a third aspect of the present invention, in the first aspect, the protective film is a dummy wiring film electrically separated from the wiring film formed on the semiconductor substrate; Since the semiconductor device includes the dummy sidewall formed on the side wall, there is an effect that it is possible to provide a semiconductor device in which the protective film can be formed simultaneously with another wiring film and the sidewall.

According to a fourth aspect of the present invention, in the third aspect, the dummy sidewall is formed of a nitride film, and the interlayer insulating film is formed of an oxide film. There is an effect that a semiconductor device which can be protected can be provided.

According to a fifth aspect of the present invention, in the first aspect, the protective film is formed of a nitride film covering the upper surface of the isolation insulating film, and the interlayer insulating film is formed of the oxide film. There is an effect that it is possible to provide a semiconductor device capable of reliably protecting the isolation insulating film.

According to the sixth aspect of the present invention, since the isolation insulating film is formed of an oxide film in the fifth aspect, the isolation insulating film can be protected without deteriorating the element isolation function. It is possible to provide such a semiconductor device.

According to the seventh aspect of the present invention, in the fifth aspect, the protective film is formed so as to cover only the upper surface of the isolation insulating film, so that the influence on other parts of the protective film is minimized. There is an effect that it is possible to provide a semiconductor device which can be used.

According to the eighth aspect of the present invention, an isolation insulating film formed by burying an element isolation groove formed in a predetermined region of a semiconductor substrate and an interlayer insulating film formed on the semiconductor substrate are formed. In a semiconductor device having an insulating film and a contact hole formed in the interlayer insulating film so as to reach the semiconductor substrate, the isolation insulating film has an etching rate lower than an etching rate of the interlayer insulating film when the contact hole is formed. Since the semiconductor device is formed using a film having characteristics, it is possible to provide a semiconductor device in which a contact hole can be formed without deteriorating the element isolation function of the isolation insulating film.

According to claim 9 of the present invention, in claim 8, the isolation insulating film is formed of an oxide film, and the interlayer insulating film is formed of any one of a nitride film and an oxide film containing boron or phosphorus. Therefore, there is an effect that it is possible to provide a semiconductor device in which a contact hole can be formed without reliably lowering the element isolation function of the isolation insulating film.

According to a tenth aspect of the present invention, in the eighth aspect, the isolation insulating film is formed of either a thermal oxide film or a nitride film, and the interlayer insulating film contains an oxide film or boron or phosphorus. Since the semiconductor device is formed of any one of the oxide films described above, it is possible to provide a semiconductor device that can be formed without reliably lowering the element isolation function of the isolation insulating film.

According to an eleventh aspect of the present invention, when the isolation insulating film of the semiconductor device according to the ninth aspect is formed of a nitride film, a base film is provided between the isolation insulating film and the semiconductor substrate. Has the effect that it is possible to provide a semiconductor device that improves the adhesion of the isolation insulating film.

According to a twelfth aspect of the present invention, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and an interlayer insulating film is formed on the semiconductor substrate. Then, a patterned resist film is formed on the interlayer insulating film, the interlayer insulating film is etched to the upper surface of the semiconductor substrate using the resist film as a mask, a contact hole is formed, and the semiconductor substrate exposed at the contact hole is heated. Oxidation is performed to form a thermal oxide film having a desired thickness, and the thermal oxide film is etched by a predetermined amount to expose the semiconductor substrate at the bottom of the contact hole. Can perform its function,
There is an effect that it is possible to provide a method for manufacturing a semiconductor device in which a contact hole can be formed without deteriorating an element isolation function.

According to a thirteenth aspect of the present invention, a groove for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and an interlayer insulating film is formed on the semiconductor substrate. Then, a patterned resist film is formed on the interlayer insulating film, the interlayer insulating film is etched down to the upper surface of the semiconductor substrate using the resist film as a mask, a preliminary contact hole is formed, and the insulating film is formed so as to cover the interlayer insulating film. Is formed in a desired amount, an insulating film is formed on the side wall and bottom surface of the preliminary contact hole, the insulating film is etched back, the semiconductor substrate at the bottom of the preliminary contact hole is exposed, and an insulating film is formed on the side wall of the preliminary contact hole. Since the contact hole is formed, the function of element isolation can be achieved by the isolation insulating film and the remaining insulating film, without deteriorating the element isolation function. There is an effect that it is possible to provide a method of manufacturing a semiconductor device that can form a contact hole.

According to a fourteenth aspect of the present invention, a device isolation groove is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the groove, and a wiring film is formed on the semiconductor substrate. Simultaneously, a dummy wiring film electrically separated from the wiring film is formed on the isolation insulating film, an interlayer insulating film is formed on the semiconductor substrate, a patterned resist film is formed on the interlayer insulating film, and the resist film is formed. Since the interlayer insulating film is etched as a mask up to the upper surface of the semiconductor substrate to form a contact hole, it is possible to provide a method of manufacturing a semiconductor device in which the isolation insulating film can be protected by the dummy wiring film. is there.

According to a fifteenth aspect of the present invention, in the thirteenth aspect, after forming the wiring film and the dummy wiring film, the etching rate of the side wall of the wiring film is lower than the etching rate of the interlayer insulating film when the contact hole is formed. A method for manufacturing a semiconductor device is provided in which a dummy sidewall is formed on a side wall of a dummy wiring film at the same time as a sidewall having low characteristics is formed, so that an isolation insulating film can be protected by the dummy wiring film and the dummy sidewall. The effect is that it is possible.

According to a sixteenth aspect of the present invention, a trench for element isolation is formed in a predetermined region of a semiconductor substrate, an isolation insulating film is formed in the trench, and a contact hole for forming a contact hole is formed on the semiconductor substrate. Forming a protective film having a lower etching rate than the etching rate of the interlayer insulating film in a later step;
An interlayer insulating film is formed on the protective film, a patterned resist film is formed on the interlayer insulating film, and a first etching is performed using the resist film as a mask until the interlayer insulating film reaches the upper surface of the protective film. Since the second etching is performed on the film to reach the upper surface of the semiconductor substrate to form a contact hole, an effect of being able to provide a method of manufacturing a semiconductor device in which an isolation insulating film can be protected by a protective film can be provided. is there.

According to a seventeenth aspect of the present invention, in the sixteenth aspect, the protective film is formed of a film having a higher etching rate than the etching rate of the isolation insulating film when forming the contact hole. There is an effect that it is possible to provide a method for manufacturing a semiconductor device in which the isolation insulating film can be surely protected by the protective film.

According to the eighteenth aspect of the present invention, a trench for element isolation is formed in a predetermined region of the semiconductor substrate, an isolation insulating film is formed in the trench, and a contact hole is formed on the semiconductor substrate when a contact hole is formed. Forming a protective film having a lower etching rate than the etching rate of the interlayer insulating film in a later step;
Perform patterning of the protective film, form so as to remain only on the isolation insulating film, form an interlayer insulating film on the semiconductor substrate, form a patterned resist film on the interlayer insulating film, using the resist film as a mask Since the interlayer insulating film is etched down to the upper surface of the semiconductor substrate and the contact hole is formed, the isolation insulating film can be protected by the protective film, and the semiconductor device is not affected by the protective film. There is an effect that a manufacturing method can be provided.

According to a nineteenth aspect of the present invention, in any one of the sixteenth to eighteenth aspects, the interlayer insulating film is formed of an oxide film, and the protective film is formed of a nitride film. There is an effect that it is possible to provide a method for manufacturing a semiconductor device in which an insulating film can be surely protected by a protective film.

According to a twentieth aspect of the present invention, in the nineteenth aspect, since the isolation insulating film is formed of an oxide film, a contact hole can be formed without deteriorating the element isolation function. There is an effect that a method for manufacturing the device can be provided.

According to a twenty-first aspect of the present invention, in a method of manufacturing a semiconductor device, a detection film is formed on a semiconductor substrate, and an interlayer insulating film is formed so as to cover the semiconductor substrate and the detection film. Form a patterned resist film on top, etch the interlayer insulating film up to the upper surface of the semiconductor substrate using the resist film as a mask, and when contact holes are formed, detect that the detection film has been reached,
Since the etching time up to the upper surface of the semiconductor substrate after the detection point is determined and controlled, the effect of being able to provide a method of manufacturing a semiconductor device capable of minimizing the decrease in the thickness of the isolation insulating film is obtained. is there.

According to a twenty-second aspect of the present invention, in the twenty-first aspect, the detection film is formed of a dummy wiring film electrically separated from the wiring film simultaneously with the wiring film formed on the semiconductor substrate. Therefore, there is an effect that it is possible to provide a method of manufacturing a semiconductor device in which a detection film can be formed without increasing the number of steps.

According to a twenty-third aspect of the present invention, an interlayer insulating film is formed on a semiconductor substrate, a patterned resist film is formed on the interlayer insulating film, and the interlayer insulating film is formed using the resist film as a mask. In a method of manufacturing a semiconductor device in which a contact hole is formed by etching all the way to the upper surface of a substrate, a current detecting portion formed by exposing the semiconductor substrate is formed on the back side of the semiconductor substrate, and a current on the exposed semiconductor substrate is detected. It is measured and determined by the current value of the semiconductor substrate that the etching at the time of forming the contact hole reaches the upper surface of the semiconductor substrate, and the end point of the etching is determined. Therefore, the semiconductor that can reduce the thickness of the isolation insulating film can be minimized. There is an effect that a method for manufacturing the device can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention;

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

FIG. 3 is a sectional view illustrating a method of manufacturing the semiconductor device according to the first embodiment of the present invention;

FIG. 4 is a sectional view illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 5 is a sectional view illustrating a method of manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 6 is a sectional view illustrating a method of manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 7 is a sectional view illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention;

FIG. 8 is a sectional view illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 9 is a sectional view illustrating a method for manufacturing a semiconductor device according to a third embodiment of the present invention;

FIG. 10 is a sectional view illustrating a method for manufacturing a semiconductor device according to a third embodiment of the present invention;

FIG. 11 is a sectional view showing a configuration of a semiconductor device according to a third embodiment of the present invention;

FIG. 12 is a sectional view illustrating a method for manufacturing a semiconductor device according to a fourth embodiment of the present invention;

FIG. 13 is a sectional view illustrating a method of manufacturing a semiconductor device according to a fifth embodiment of the present invention.

FIG. 14 is a sectional view illustrating a method for manufacturing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 15 is a sectional view illustrating a method of manufacturing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 16 is a sectional view showing a configuration of a semiconductor device according to a seventh embodiment of the present invention.

FIG. 17 is a sectional view illustrating a method of manufacturing a semiconductor device according to a seventh embodiment of the present invention.

FIG. 18 is a cross-sectional view showing a conventional method for manufacturing a semiconductor device.

FIG. 19 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 20 is a cross-sectional view for describing a problem of a conventional semiconductor device.

[Explanation of symbols]

1 semiconductor substrate, 2 first silicon oxide film, 3 polycrystalline silicon film, 4, 35, 39 first resist film,
5, 36 groove, 6, 6a second silicon oxide film, 6
b, 6d, 31b, 37a Isolation insulating film, 11, 50
Conductive film, 12, 51 Gate electrode, 13, 18 Dummy wiring film, 14, 53 Side wall, 15, 23, 2
8, 32, 38, 54, 59 interlayer insulating film, 16 second
Resist film, 10a, 17, 21, 26, 30, 3
4, 40, 42, 42a, 48, 49, 58, 60 contact holes, 19, 22 silicon nitride film, 20
Dummy sidewalls, 24, 29, 33, 44, 5
5,64 resist film, 25,56,65 opening, 2
7 protective film, 31, 31a, 43, 43a thermal oxide film,
37 nitride film, 41 base film, 45, 46 preliminary contact hole, 47, 47a oxide film, 52 detection film, 5
7 Preparatory aperture, 61 current detector, 62 current detector, 63 stage.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuhiro Fuka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Nobuaki Yamanaka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd.

Claims (23)

[Claims] An isolation insulating film formed by filling a trench for element isolation formed in a predetermined region of a semiconductor substrate;
In a semiconductor device comprising: an interlayer insulating film formed on the semiconductor substrate; and a contact hole formed in the interlayer insulating film so as to reach the semiconductor substrate, wherein the contact hole is formed on the isolation insulating film. A semiconductor device comprising a protective film having an etching rate lower than an etching rate of the interlayer insulating film at the time of formation. 2. The semiconductor device according to claim 1, wherein the protective film is formed of a dummy wiring film that is electrically separated from a wiring film formed on the semiconductor substrate. 3. A protection film comprising: a dummy wiring film electrically separated from a wiring film formed on a semiconductor substrate; and a dummy sidewall formed on a side wall of the dummy wiring film. 2. The semiconductor device according to claim 1, wherein: 4. The semiconductor device according to claim 3, wherein the dummy sidewall is formed of a nitride film, and the interlayer insulating film is formed of an oxide film. 5. The semiconductor device according to claim 1, wherein the protective film is formed of a nitride film covering an upper surface of the isolation insulating film, and the interlayer insulating film is formed of an oxide film. 6. The semiconductor device according to claim 5, wherein the isolation insulating film is formed of an oxide film. 7. The semiconductor device according to claim 5, wherein the protection film is formed so as to cover only the upper surface of the isolation insulating film. 8. An isolation insulating film formed by filling a trench for element isolation formed in a predetermined region of a semiconductor substrate,
In a semiconductor device comprising: an interlayer insulating film formed on the semiconductor substrate; and a contact hole formed in the interlayer insulating film so as to reach the semiconductor substrate, wherein the isolation insulating film is formed on the contact hole. A semiconductor device formed of a film having an etching rate lower than an etching rate of the interlayer insulating film at the time. 9. The isolation insulating film is formed of an oxide film, and the interlayer insulating film is formed of a nitride film or an oxide film containing boron or phosphorus.
3. The semiconductor device according to claim 1. 10. The isolation insulating film is formed of a thermal oxide film or a nitride film, and the interlayer insulating film is formed of an oxide film or an oxide film containing boron or phosphorus. 9. The semiconductor device according to claim 8, wherein: 11. The semiconductor device according to claim 9, wherein when the isolation insulating film is formed of a nitride film, a base film is interposed between the isolation insulating film and the semiconductor substrate. Semiconductor device. 12. A step of forming an element isolation groove in a predetermined region of a semiconductor substrate, a step of forming an isolation insulating film in the groove, and a step of forming an interlayer insulating film on the semiconductor substrate. Forming a patterned resist film on the interlayer insulating film, etching the interlayer insulating film to the upper surface of the semiconductor substrate using the resist film as a mask, forming a contact hole, and exposing the contact hole. Forming a thermal oxide film having a desired thickness by thermally oxidizing the semiconductor substrate, and exposing the semiconductor substrate at the bottom of the contact hole by etching a predetermined amount of the thermal oxide film. A method for manufacturing a semiconductor device. 13. A step of forming a groove for element isolation in a predetermined region of a semiconductor substrate, a step of forming an isolation insulating film in the groove, and a step of forming an interlayer insulating film on the semiconductor substrate. Forming a patterned resist film on the interlayer insulating film, etching the interlayer insulating film to the upper surface of the semiconductor substrate using the resist film as a mask, and forming a preliminary contact hole; Forming a desired amount of an insulating film so as to cover and forming the insulating film on the side walls and the bottom surface of the preliminary contact hole; and etching back the insulating film to expose the semiconductor substrate at the bottom of the preliminary contact hole. Forming a contact hole in which the insulating film is formed on a side wall of the preliminary contact hole. Law. 14. A step of forming a trench for element isolation in a predetermined region of a semiconductor substrate, a step of forming an isolation insulating film in the trench, and a step of forming a wiring film on the semiconductor substrate and simultaneously forming the isolation insulating film. Forming a dummy wiring film electrically separated from the wiring film on the film, forming an interlayer insulating film on the semiconductor substrate, and forming a patterned resist film on the interlayer insulating film; Forming a contact hole by etching the interlayer insulating film to the upper surface of the semiconductor substrate using the resist film as a mask. 15. After forming a wiring film and a dummy wiring film,
Forming, on the side wall of the wiring film, a side wall having a characteristic that the etching rate is lower than the etching rate of the interlayer insulating film at the time of forming the contact hole; The method for manufacturing a semiconductor device according to claim 14, wherein 16. A step of forming a groove for element isolation in a predetermined region of a semiconductor substrate, a step of forming an isolation insulating film in the groove, and a step of forming a contact hole on the semiconductor substrate in a later step Forming a protective film having a lower etching rate than the etching rate of the insulating film;
Forming the interlayer insulating film on the protective film, forming a patterned resist film on the interlayer insulating film, and using the resist film as a mask, extending the interlayer insulating film to the upper surface of the protective film. Perform a first etch,
Performing a second etching of the protective film to the upper surface of the semiconductor substrate to form a contact hole. 17. The method of manufacturing a semiconductor device according to claim 16, wherein the protective film is formed of a film having an etching rate higher than an etching rate of the isolation insulating film when forming the contact hole. 18. A step of forming a groove for element isolation in a predetermined region of a semiconductor substrate, a step of forming an isolation insulating film in the groove, and a step of forming a contact hole on the semiconductor substrate in a later step. Forming a protective film having a lower etching rate than the etching rate of the insulating film;
A step of patterning the protective film so as to remain only on the isolation insulating film, a step of forming the interlayer insulating film on the semiconductor substrate, and a resist film patterned on the interlayer insulating film Forming a contact hole using the resist film as a mask and etching the interlayer insulating film to the upper surface of the semiconductor substrate to form a contact hole. 19. The method according to claim 16, wherein the interlayer insulating film is formed of an oxide film, and the protective film is formed of a nitride film. 20. The method according to claim 19, wherein the isolation insulating film is formed of an oxide film. 21. A method for manufacturing a semiconductor device, comprising: a step of forming a detection film on a semiconductor substrate; and a step of forming an interlayer insulation film so as to cover the semiconductor substrate and the detection film. A patterned resist film is formed thereon, and the interlayer insulating film is etched to reach the upper surface of the semiconductor substrate using the resist film as a mask, and when a contact hole is formed, it is detected that the detection film has been reached, A method of manufacturing a semiconductor device, comprising determining and controlling an etching time until reaching the upper surface of the semiconductor substrate after the detection. 22. The semiconductor device according to claim 21, wherein the detection film is formed of a dummy wiring film electrically separated from the wiring film simultaneously with the wiring film formed on the semiconductor substrate. Manufacturing method. 23. A step of forming an interlayer insulating film on a semiconductor substrate, forming a patterned resist film on the interlayer insulating film, and reaching the upper surface of the semiconductor substrate using the resist film as a mask. Etch until
Forming a contact hole on the back side of the semiconductor substrate, forming a current detecting portion having the semiconductor substrate exposed, and detecting the current on the exposed semiconductor substrate. A method for manufacturing a semiconductor device, comprising: measuring and judging from the current value of the semiconductor substrate that the etching at the time of forming the contact hole reaches the upper surface of the semiconductor substrate, and determining the end point of the etching.