JPH0945675A - Semiconductor integrated circuit device and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a semiconductor integrated circuit device having excellent electric characteristics and a method for manufacturing the semiconductor integrated circuit device which can be easily manufactured. A step of forming a silicon nitride film to be a mask film for surface oxidation in a plurality of selective regions of a semiconductor element forming region and a field insulating film forming region on the surface of the n-type semiconductor region 3, and a mask of the silicon nitride film As a result, thermal oxidation treatment of the n-type semiconductor region 3 is performed, and the field silicon oxide film 6 is formed on the surface of the n-type semiconductor region 3. It includes a step of forming a plurality of convex portions inside the field silicon oxide film 6 and a step of forming a semiconductor element in the element forming region of the n-type semiconductor region 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit device and a method of manufacturing the same, and more particularly to a technique effective when applied to a method of manufacturing a semiconductor integrated circuit device having excellent electric characteristics.

[0002]

2. Description of the Related Art In a method of manufacturing a semiconductor integrated circuit device studied by the present inventor, a LOCOS (Local Oxidation of SOT) which is an insulating film for element isolation is selectively formed in a semiconductor region.
After forming a silicon oxide film which is a field insulating film having an (ilicon) structure by a thermal oxidation process, a bipolar transistor such as an npn transistor is formed in an active region of a semiconductor region.

Documents describing the manufacturing technology of bipolar transistors include, for example, Japanese Patent Laid-Open No.
There is one described in Japanese Patent Publication No. 8-43573.

[0004]

However, the inventor of the present invention has found that the above-mentioned manufacturing technique of the semiconductor integrated circuit device has the following problems.

That is, in order to improve the manufacturing yield of the semiconductor integrated circuit device, as a result of analyzing the npn transistor having deteriorated electric characteristics, it was found that the breakdown voltage between the collector and the emitter was lowered.

As a result of analyzing the cause of the decrease in the collector-emitter breakdown voltage of the npn transistor in the semiconductor integrated circuit device, a silicon oxide film which is a manufacturing process of the semiconductor integrated circuit device is formed by a CVD (Chemical Vapor Deposition) method. During wafer processing, heavy metal contamination occurs, and particularly iron (Fe) is concentrated at the end of the silicon oxide film of the LOCOS structure. Due to the iron contamination, between the collector and emitter of the npn transistor in the semiconductor integrated circuit device. It was found that the breakdown voltage had dropped.

An object of the present invention is to provide a semiconductor integrated circuit device having excellent electric characteristics.

Another object of the present invention is to provide a method of manufacturing a semiconductor integrated circuit device which can easily manufacture a semiconductor integrated circuit device having excellent electric characteristics.

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

[0010]

The typical ones of the inventions disclosed in the present invention will be outlined below.

According to the method of manufacturing a semiconductor integrated circuit device of the present invention, a surface oxidation mask film is formed in a plurality of selective regions of a semiconductor element forming region and a field insulating film forming region on the surface of a semiconductor region such as a semiconductor substrate. Process,
Thermal oxidation treatment of the semiconductor region is performed by using the surface oxidation mask film as a mask, and a silicon oxide film serving as a field insulating film is formed on the surface of the semiconductor region, thereby forming a convex portion formed at an end portion of the silicon oxide film. It has a step of forming a plurality of similar convex portions inside a silicon oxide film and a step of forming a semiconductor element in a semiconductor element forming region of a semiconductor region.

[0012]

[Action]

(1) According to the above-described method for manufacturing a semiconductor integrated circuit device of the present invention, the surface oxidation mask film is used as a mask to thermally oxidize the semiconductor region, and a silicon oxide film serving as a field insulating film is formed on the surface of the semiconductor region. By forming
By having a step of forming a plurality of protrusions similar to the protrusions formed on the end portion of the silicon oxide film inside the silicon oxide film, a plurality of protrusions are formed on the end portion and inside the silicon oxide film to be the field insulating film. Since the protrusions are formed, iron added to the silicon oxide film as heavy metal contamination in the manufacturing process can be dispersed in the plurality of protrusions of the silicon oxide film.

FIG. 9 is a graph showing the results of the study by the present inventor. The manufacturing yield and the silicon oxide serving as a field insulating film due to the collector-emitter breakdown voltage defect of the npn transistor in the semiconductor integrated circuit device. It is a graph which shows the relationship with the iron concentration in the convex part of the edge part of a film | membrane.

As is clear from FIG. 9, the lower the iron concentration in the convex portion at the end of the silicon oxide film which becomes the field insulating film, the lower the collector-emitter breakdown voltage of the npn transistor in the semiconductor integrated circuit device. The present inventor has found that the manufacturing yield is increased.

FIG. 10 is a graph showing the results of the study conducted by the present inventor. The center side, the orientation flat side, and the top side of the wafer opposite to the orientation flat side in a wafer having a semiconductor region for manufacturing a semiconductor integrated circuit device. FIG. 6 is a graph showing the relationship between the protrusions at the ends of the silicon oxide film serving as the field insulating film and the iron concentration at each position.

As is clear from FIG. 10, the iron concentration differs depending on the position of the wafer, and the iron concentration in the convex portion at the end of the silicon oxide film which becomes the field insulating film on the orientation flat side and the top side of the center of the wafer is different. The inventor has found that it is high.

The above-described method for manufacturing a semiconductor integrated circuit device of the present invention takes into consideration the results of the study conducted by the present inventor, and is present in the convex portion of the silicon oxide film which is the field insulating film around the semiconductor element. By using a small amount of iron, the iron does not deteriorate the electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor, and a semiconductor element having excellent electrical characteristics can be manufactured. At the same time, a semiconductor integrated circuit device can be manufactured with a high manufacturing yield.

(2) According to the method for manufacturing a semiconductor integrated circuit device of the present invention described above, the surface is formed in a plurality of selective regions of the semiconductor element forming region and the field insulating film forming region on the surface of the semiconductor region such as a semiconductor substrate. After forming the oxidation mask film, using the surface oxidation mask film as a mask,
When performing thermal oxidation treatment on the semiconductor region and forming a silicon oxide film to be a field insulating film on the surface of the semiconductor region,
By having a step of forming a plurality of protrusions similar to the protrusions formed at the end portion of the silicon oxide film inside the silicon oxide film, a plurality of protrusions are formed inside when forming the silicon oxide film to be the field insulating film. Since the individual protrusions are formed, it is possible to form a plurality of protrusions on the silicon oxide film using a simple manufacturing process.

As a result, the manufacturing process of the semiconductor integrated circuit device can be simplified and the number of manufacturing processes can be minimized.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for explaining the embodiments, those having the same function are designated by the same reference numerals, and a duplicate description will be omitted.

(Embodiment 1) FIGS. 1 to 5 are schematic sectional views showing a manufacturing process of a semiconductor integrated circuit device according to an embodiment of the present invention. A method of manufacturing a semiconductor integrated circuit device according to the present invention will be described with reference to FIGS.

First, as shown in FIG. 1, an n-type semiconductor region 2 having a high impurity concentration to be a buried region is formed on the surface of a semiconductor substrate 1 made of, for example, p-type silicon single crystal, and then an epitaxial growth method is performed on the n-type semiconductor region 2. Thus, the n-type semiconductor region 3 is formed. These manufacturing steps can be performed using prior art. Although not shown, n
A p-type semiconductor region for element isolation by a pn junction is formed in a selective region of the type semiconductor region 3.

Next, after forming a silicon oxide film (not shown) on the surface of the n-type semiconductor region 3, for example, a silicon nitride film 4 serving as a surface oxidation mask film is formed, and then a photolithography technique and selective etching are performed. A selective region of the silicon nitride film 4 is removed by using a technique to form a pattern of the silicon nitride film 4 which serves as a surface oxidation mask film when forming a field silicon oxide film which is an element isolation insulating film. .

The above-mentioned silicon oxide film is formed to relieve the stress between the silicon nitride film 4 and the n-type semiconductor region 3, and is a thin pad oxide film (pad oxid film).
It is intended to function as e).

Then, as shown in FIG. 2, using the silicon nitride film 4 as a mask, the n-type semiconductor region 3 whose surface is exposed is etched to form a plurality of grooves 5 at predetermined intervals.

Next, as shown in FIG. 3, using the silicon nitride film 4 as a mask, a thermal oxidation process is performed to form a field silicon oxide film 6 on the surface of the n-type semiconductor region 3.

That is, the field silicon oxide film 6
Are formed using a LOCOS (Local Oxidation of Silicon) technique. At this time, since the groove 5 is formed in advance in the region where the field silicon oxide film 6 is formed, the field silicon oxide film 6 is embedded in the n-type semiconductor region 3 to form the field silicon oxide from the n-type semiconductor region 3. The protruding height of the membrane 6 can be reduced.

It should be noted that, without providing the groove 5, the silicon nitride film 4 is used as a mask to perform thermal oxidation treatment,
The field silicon oxide film 6 may be formed on the surface of the type semiconductor region 3.

The field silicon oxide film 6 is formed as a thick film in the n-type semiconductor region 3 which is not protected by the silicon nitride film 4.

Since the silicon oxide in the n-type semiconductor region 3 is consumed by the thermal oxidation process in this case, a step is formed in the finished structure.

Further, since the field silicon oxide film 6 is formed below the end portion of the silicon nitride film 4 as well, the lateral spread and the vertical spread thereof are substantially the same, so that the bird's beak is formed in this region. A (bird's beak) area is formed.

That is, a bird's beak region is formed at the end of the field silicon oxide film 6 so that a convex portion is formed in that region.

The feature of this embodiment is that the convex portion of the bird's beak region is positively utilized, and in each region of the field silicon oxide film 6, iron which becomes heavy metal contamination is concentrated especially on the convex portion. Therefore, a plurality of the protrusions are formed on the field silicon oxide film 6, and iron is dispersed in each of the protrusions, particularly in the end portion of the field silicon oxide film 6 around the element formation region. The amount of iron existing in the convex portion is reduced to reduce the phenomenon that the electric characteristics of the element are deteriorated.

Specifically, the silicon nitride film 4 serving as a mask when the field insulating film is formed by the thermal oxidation process is provided in a plurality of selective regions of the field insulating film forming region, and the field is formed by the thermal oxidation process. Silicon oxide film 6
When forming the above, a plurality of bird's beak regions are formed inside the field silicon oxide film 6, and a convex portion for dispersing iron that becomes heavy metal contamination is formed in the region.

Next, as shown in FIG. 4, a work of removing the unnecessary silicon nitride film 4 by etching is performed.

Next, as shown in FIG. 5, for example, an npn transistor is formed in the element forming region.

That is, after forming the silicon oxide film 7 in the element formation region by the CVD method, for example, ion implantation of phosphorus (P) and boron (B) and an annealing treatment are performed to form an n-type contact region of the collector with a high impurity concentration. 8. A high-impurity-concentration p-type contact region 9 and a p-type base region 10 are formed.

Next, the emitter electrode forming region of the silicon oxide film 7 is selectively removed to form an opening, and the emitter electrode 11 is formed in that region using the polycrystalline silicon film, and then the polycrystalline silicon film is formed. The added n-type impurity such as arsenic (As) is diffused to form the n-type emitter region 12.

By the use of the manufacturing process of the field silicon oxide film 6 described above, the n-type contact region 8 of the collector and the p-type contact region 9 of the base, which are the extraction regions to the surface of the collector electrode of the npn transistor, are formed. The field silicon oxide film may be formed between the p-type base regions 10.

Next, although not shown, a wiring film having a multi-layer wiring structure and an interlayer insulating film are formed, and the manufacturing process of the semiconductor integrated circuit device is completed.

According to the method for manufacturing the semiconductor integrated circuit device of the present embodiment described above, the n-type semiconductor region 3 is thermally oxidized by using the plurality of silicon nitride films 4 which are surface oxidation mask films as masks, By forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3, a plurality of projections similar to the projections formed at the ends of the field silicon oxide film 6 are formed inside the field silicon oxide film 6. By including the step of
Since a plurality of convex portions are formed at the ends and inside of the field silicon oxide film 6, the plurality of convex portions of the field silicon oxide film 6 are contaminated as heavy metal contamination in the manufacturing process.
The iron taken in can be dispersed in the plurality of convex portions.

As a result, a small amount of iron is present in the convex portion of the field silicon oxide film 6 around the semiconductor element, and this iron causes the electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor. It is possible to manufacture a semiconductor element having excellent electric characteristics without deteriorating the characteristics, and it is possible to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

Further, according to the method for manufacturing the semiconductor integrated circuit device of the present embodiment described above, surface oxidation is performed on a plurality of selective regions of the element forming region and the field insulating film forming region on the surface of the n-type semiconductor region 3. After the silicon nitride film 4 serving as a mask film is formed, the silicon nitride film 6 serving as a surface oxidation mask film is used as a mask to perform thermal oxidation treatment on the n-type semiconductor region 3 to perform field oxidation on the surface of the n-type semiconductor region 3. By forming a plurality of protrusions similar to the protrusions formed at the end of the field silicon oxide film 6 inside the field silicon oxide film 6 when forming the silicon film 6, Since a plurality of protrusions are formed inside when forming the film 6, it is necessary to form a plurality of protrusions on the field silicon oxide film 6 using a simple manufacturing process. It can be.

As a result, the manufacturing process of the semiconductor integrated circuit device can be simplified and the number of manufacturing processes can be minimized.

According to the method for manufacturing the semiconductor integrated circuit device of the present embodiment described above, the convex portion of the bird's beak region of the field silicon oxide film 6 is positively utilized, and in each region of the field silicon oxide film 6. In particular, since iron, which is a heavy metal contamination, is concentrated on the convex portions, a plurality of the convex portions are formed on the field silicon oxide film 6, and the iron is dispersed in each convex portion. The amount of iron existing in the convex portion at the end portion of the field silicon oxide film 6 around the element forming region is reduced to reduce the phenomenon that the electric characteristics of the element are deteriorated.

Specifically, the silicon nitride film 4 serving as a mask when the field insulating film is formed by the thermal oxidation process is provided in a plurality of selective regions of the field insulating film formation region, and the field is formed by the thermal oxidation process. Silicon oxide film 6
During the formation, a plurality of bird's beak regions are formed inside the field silicon oxide film 6, and a convex portion for dispersing iron that becomes heavy metal contamination is formed in the region.

Therefore, according to the method of manufacturing the semiconductor integrated circuit device of this embodiment described above, the field silicon oxide film 6 is formed in the n-type semiconductor region 3 formed on the semiconductor substrate 1.
To form the semiconductor substrate 1 or the SOI.
The field silicon oxide film 6 may be formed on the surface of the semiconductor region of the (Silicon on Insulator) substrate.

Further, in the method of manufacturing the semiconductor integrated circuit device of this embodiment described above, the field silicon oxide film 6 is formed in the n-type semiconductor region 3 formed on the semiconductor substrate 1 and the npn is formed in the element forming region. Although forming a transistor, the n-type semiconductor region 3, the semiconductor substrate 1 or the SO
After the field silicon oxide film 6 is formed on the surface of the semiconductor region in the I substrate, a bipolar transistor such as a pnp transistor is formed in the element forming region of the semiconductor region.
MOSFET, CMOSFET or BiCMOS FE
Various semiconductor elements such as T can be formed.

According to the method of manufacturing the semiconductor integrated circuit device of the present embodiment, a small amount of iron is present in the convex portion of the field silicon oxide film 6 around the semiconductor element, so that various semiconductors are produced by this iron. The electric characteristics of the element are not deteriorated, a semiconductor element having excellent electric characteristics can be manufactured, and a semiconductor integrated circuit device can be manufactured with a high manufacturing yield by a simple manufacturing process.

(Embodiment 2) FIG. 6 is a schematic sectional view showing a manufacturing process of a semiconductor integrated circuit device according to another embodiment of the present invention.

In the manufacturing process of the semiconductor integrated circuit device of this embodiment, in the manufacturing process of forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3, the oxidation having a plurality of bird's beak regions on the back surface of the semiconductor substrate 1 is performed. Silicon film 1
3 is formed.

The manufacturing process of the silicon oxide film 13 is a manufacturing process similar to the manufacturing process of forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3 in the first embodiment described above. Although the silicon nitride film 4 is provided in the element formation region of the semiconductor region 3, the provision of the silicon nitride film 4 in the element formation region is omitted because there is no region to be the element formation region on the back surface of the semiconductor substrate. There is a point.

Except for the manufacturing process described above, the manufacturing process is the same as the manufacturing process for the semiconductor integrated circuit device according to the first embodiment described above, and a description thereof will be omitted.

In this embodiment, by forming a plurality of bird's beak regions of the silicon oxide film 13 formed on the back surface of the semiconductor substrate, convex portions are formed in those regions.

The feature of this embodiment is that the convex portion of the bird's beak region is positively utilized, and in each region of the field silicon oxide film 6 and the silicon oxide film 13, iron which becomes heavy metal contamination particularly in the convex portion is formed. Are concentrated on the field silicon oxide film 6 and the silicon oxide film 13 so that iron is dispersed in each of the convex portions, particularly in the periphery of the element formation region. The amount of iron present in the convex portion at the end portion of the field silicon oxide film 6 is reduced to reduce the phenomenon that the electric characteristics of the element are deteriorated.

Specifically, nitriding is used as a mask when the field silicon oxide film 6 and the silicon oxide film 13 are formed by thermal oxidation in the field insulating film forming region and a plurality of selective regions on the back surface of the semiconductor substrate 1. When the silicon film 4 is provided and the field silicon oxide film 6 and the silicon oxide film 13 are formed by thermal oxidation, the field silicon oxide film 6 and the silicon oxide film 1 are formed.
A plurality of bird's beak regions are formed in the inside of No. 3, and a convex portion for dispersing iron as heavy metal contamination is formed in the region.

According to the method of manufacturing the semiconductor integrated circuit device of the present embodiment described above, the n-type semiconductor region 3 and the back surface of the semiconductor substrate 1 are formed on the back surfaces of the n-type semiconductor region 3 and the semiconductor substrate 1 by using the plurality of silicon nitride films 4 as the surface oxidation mask film as a mask. By performing a thermal oxidation process to form the field silicon oxide film 6 on the surface of the n-type semiconductor region 3 and the silicon oxide film 13 on the back surface of the semiconductor substrate 1, the field silicon oxide film 6 and the silicon oxide film 13 are formed. By including a plurality of protrusions similar to the protrusions formed at the ends inside the field silicon oxide film 6 and the silicon oxide film 13,
Field silicon oxide film 6 and silicon oxide film 13
Since a plurality of protrusions are formed at the ends and inside of the field silicon oxide film 6 and the silicon oxide film 13, the field silicon oxide film 6 and the silicon oxide film 13 of these protrusions are contaminated as heavy metal contamination in the manufacturing process. The iron taken in can be dispersed in the plurality of convex portions.

As a result, a small amount of iron is present in the convex portion of the field silicon oxide film 6 around the semiconductor element, so that the electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor are deteriorated. It is possible to manufacture a semiconductor element having excellent electric characteristics, and it is possible to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

According to the method of manufacturing the semiconductor integrated circuit device of the present embodiment described above, the silicon oxide film 13 is formed on the back surface of the semiconductor substrate 1, and the silicon oxide film 13 is formed with a plurality of protrusions. It is possible to disperse the iron taken into the field silicon oxide film 6 and the silicon oxide film 13 as heavy metal contamination in the silicon oxide film 13 of the plurality of protrusions into the plurality of protrusions in the manufacturing process.

Therefore, as a mode of the field silicon oxide film 6 formed on the surface of the n-type semiconductor region 3, the convex portions are formed only at the end portions of the field silicon oxide film 6 similar to the conventional field silicon oxide film. It is possible to apply the field silicon oxide film 6 having no convex portion formed therein.

In this case, since iron, which is a heavy metal contamination, can be dispersed by the plurality of protrusions in the silicon oxide film 13 formed on the back surface of the semiconductor substrate 1, the field silicon oxide film 6 has a simple shape similar to the conventional one. It is possible to adopt a mode in which it is not necessary to provide a plurality of protrusions inside the field silicon oxide film 6 by forming it by various manufacturing processes.

(Embodiment 3) FIG. 7 is a schematic sectional view showing a manufacturing process of a semiconductor integrated circuit device according to another embodiment of the present invention.

The feature of the manufacturing process of the semiconductor integrated circuit device of the present embodiment is that the element formation region is arranged in a region separated from the field insulating film formation region so that the end of the field silicon oxide film 6 around the element formation region is formed. The phenomenon that the electric characteristics of the element are deteriorated by the iron existing in the convex portion of the portion is reduced.

The manufacturing process of the field silicon oxide film 6 is the same as the manufacturing process of forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3 in the first embodiment, but the field silicon oxide film is formed. By disposing the element forming region in a region separated from 6, the number of the convex portions formed inside the field silicon oxide film 6 is smaller than that of the field silicon oxide film 6 in the first embodiment described above. be able to.

Except for the manufacturing steps described above, the description is omitted because it is the same as the manufacturing steps of the semiconductor integrated circuit device of the first embodiment described above.

(Embodiment 4) FIG. 8 is a plan view showing a wafer used in a manufacturing process of a semiconductor integrated circuit device which is another embodiment of the present invention.

The manufacturing process of the semiconductor integrated circuit device according to the present embodiment is performed in the manufacturing process of forming the field silicon oxide film 6 around the surface of the n-type semiconductor region 3 in the first embodiment in the wafer 14 described above. The silicon oxide film 17 having a plurality of bird's beak regions is formed around the element forming region.

In FIG. 8, 15 indicates the orientation flat portion of the wafer 14, and 16 indicates the top portion of the wafer 14.

The manufacturing process of the silicon oxide film 17 is a manufacturing process similar to the manufacturing process of forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3 in the first embodiment described above. Since the silicon nitride film 4 is also provided around the element forming region of the n-type semiconductor region 3 in FIG. 1 and there is no region to be the element forming region in the peripheral portion of the wafer 14, silicon oxide having a plurality of convex portions in this region is formed. The point is to form the film 17.

Except for the manufacturing process described above, the manufacturing process is the same as the manufacturing process for the semiconductor integrated circuit device according to the first embodiment described above, and a description thereof will be omitted.

In this embodiment, a plurality of bird's beak regions are formed in the silicon oxide film 17 formed on the peripheral portion of the wafer 14, so that the convex portions are formed in those regions.

The feature of the present embodiment is that the convex portion of the bird's beak region is positively utilized, and in each region of the field silicon oxide film 6 and the silicon oxide film 17, iron which becomes heavy metal contamination particularly in the convex portion. Are formed in the field silicon oxide film 6 and the silicon oxide film 17, so that iron is dispersed in each of the protrusions, and especially in the field around the element formation region. Iron present in the convex portion at the end of the silicon oxide film 6 is reduced to reduce the phenomenon that the electric characteristics of the element are deteriorated.

In particular, as is clear from FIG. 10, in the conventional method in which the silicon oxide film 17 of this embodiment is not provided, the iron concentration differs depending on the position of the wafer 14,
Although there was a tendency for the iron concentration in the protrusions at the ends of the field silicon oxide film on the orientation flat side and the top side of the wafer 14 to be higher than the center, the provision of the silicon oxide film 17 of this example provided Since the iron in the peripheral portion can be dispersed, the iron concentration can be reduced.

According to the method of manufacturing the semiconductor integrated circuit device of the present embodiment described above, the thermal oxidation treatment of the n-type semiconductor region 3 in the wafer 14 is performed by using the plurality of silicon nitride films 4 which are surface oxidation mask films as masks. Then, the field silicon oxide film 6 is formed on the surface of the n-type semiconductor region 3, and the silicon oxide film 17 is formed on the peripheral portion of the wafer 14. As a result, a convex portion similar to the convex portion formed at the end portions of the field silicon oxide film 6 and the silicon oxide film 17 is formed in the field silicon oxide film 6 and the silicon oxide film 1.
Since a plurality of convex portions are formed inside and inside the field silicon oxide film 6 and the silicon oxide film 17 by having the step of forming a plurality of convex portions in the inside of the field silicon oxide film 7. The iron taken into the field silicon oxide film 6 and the silicon oxide film 17 as heavy metal contamination in the film 6 and the silicon oxide film 17 in the manufacturing process can be dispersed in the plurality of protrusions.

As a result, a small amount of iron is present in the convex portion of the field silicon oxide film 6 around the semiconductor element, and this iron causes, for example, the collector-emitter breakdown voltage of the npn transistor, and the like. It is possible to manufacture a semiconductor element having excellent electric characteristics without deteriorating the characteristics, and it is possible to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

According to the method of manufacturing a semiconductor integrated circuit device of this embodiment described above, the silicon oxide film 17 is formed on the peripheral portion of the wafer 14, and a plurality of convex portions are formed on the silicon oxide film 17. The iron taken into the field silicon oxide film 6 and the silicon oxide film 17 as heavy metal contamination in the silicon oxide film 17 of the plurality of protrusions in the manufacturing process can be dispersed in the plurality of protrusions.

As a result, the manufacturing process of the field silicon oxide film 6 is the same as the manufacturing process of forming the field silicon oxide film 6 on the surface of the n-type semiconductor region 3 in the above-described first embodiment, but the wafer Since the silicon oxide film 17 is formed in the peripheral portion of 14, the number of protrusions formed inside the field silicon oxide film 6 is smaller than that of the field silicon oxide film 6 in the first embodiment described above. be able to.

As a mode of the field silicon oxide film 6 formed on the surface of the n-type semiconductor region 3, a convex portion is formed only on the end portion of the field silicon oxide film 6 similar to the conventional field silicon oxide film. It is possible to apply the field silicon oxide film 6 having no convex portion formed therein.

In this case, since iron, which is a heavy metal contamination, can be dispersed by the plurality of protrusions in the silicon oxide film 17 formed on the peripheral portion of the wafer 14, the field silicon oxide film 6 has a simple shape similar to the conventional one. It is possible to adopt a mode in which it is not necessary to provide a plurality of protrusions inside the field silicon oxide film 6 by forming it by various manufacturing processes.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

Although the present invention is the manufacturing technique of the bipolar type semiconductor integrated circuit device in the first embodiment, B
The present invention can be applied to a manufacturing technology of a semiconductor integrated circuit device having iMOS, BiCMOS or MOS or another structure.

[0082]

The effects obtained by the typical ones of the inventions disclosed in this application will be briefly described as follows.
It is as follows.

(1) According to the method of manufacturing the semiconductor integrated circuit device of the present invention, the semiconductor region is thermally oxidized by using the plurality of surface oxidation mask films as masks, and the field silicon oxide film is formed on the surface of the semiconductor region. By forming
By having a step of forming a plurality of convex portions similar to the convex portions formed at the end portion of the field silicon oxide film inside the field silicon oxide film, a plurality of convex portions are formed at the end portion and inside the field silicon oxide film. Since the portions are formed, iron that is taken into the field silicon oxide film as heavy metal contamination in the manufacturing process can be dispersed in the plurality of convex portions on the field silicon oxide film of the plurality of convex portions.

As a result, a small amount of iron is present in the convex portion of the field silicon oxide film around the semiconductor element, and the iron causes electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor. It is possible to manufacture a semiconductor element having excellent electrical characteristics and to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

(2) According to the method for manufacturing a semiconductor integrated circuit device of the present invention, the surface oxidation mask film is formed in a plurality of selective regions of the element forming region and the field insulating film forming region on the surface of the semiconductor region. After that, the surface oxidation mask film is used as a mask to perform thermal oxidation treatment of the semiconductor region,
When forming the field silicon oxide film on the surface of the semiconductor region, by having a step of forming a plurality of projections similar to the projections formed at the end of the field silicon oxide film inside the field silicon oxide film. Since a plurality of protrusions are formed inside when forming the field silicon oxide film, it is possible to form the plurality of protrusions on the field silicon oxide film using a simple manufacturing process.

As a result, the manufacturing process of the semiconductor integrated circuit device can be simplified and the number of manufacturing processes can be minimized.

(3) According to the method for manufacturing a semiconductor integrated circuit device of the present invention, thermal oxidation treatment is performed on the back surface of the semiconductor region and the semiconductor substrate by using the plurality of mask films for surface oxidation as masks, and the surface of the semiconductor region is exposed. By forming the field silicon oxide film and the silicon oxide film on the back surface of the semiconductor substrate, the field silicon oxide film and the convex portion similar to the convex portion formed at the end portion of the silicon oxide film are formed on the field silicon oxide film and the convex portion. By including a step of forming a plurality of silicon oxide films inside, a plurality of convex portions are formed at the ends and inside of the field silicon oxide film and the silicon oxide film. Field silicon oxide film and silicon oxide as heavy metal contamination in the manufacturing process on the film and silicon oxide film Iron can be dispersed to a plurality of convex portions to be taken into.

As a result, a small amount of iron is present in the convex portions of the field silicon oxide film around the semiconductor element, which deteriorates the electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor. It is possible to manufacture a semiconductor element having excellent electric characteristics, and also possible to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

(4) According to the method of manufacturing a semiconductor integrated circuit device of the present invention, by disposing the element forming region in a region separated from the field insulating film forming region, the field silicon oxide film around the element forming region is formed. It is possible to reduce the phenomenon that the electric characteristics of the element are deteriorated by the iron existing in the convex portion at the end portion.

(5) According to the method of manufacturing a semiconductor integrated circuit device of the present invention, the semiconductor region of the wafer is thermally oxidized by using the plurality of surface oxidation mask films as masks,
By forming the field silicon oxide film on the surface of the semiconductor region and forming the silicon oxide film on the peripheral portion of the wafer, a convex portion similar to the convex portion formed at the end portion of the field silicon oxide film and the silicon oxide film is formed. By including a step of forming a plurality of field silicon oxide films and the inside of the silicon oxide film, a plurality of convex portions are formed at the ends and inside of the field silicon oxide film and the silicon oxide film. The iron taken into the field silicon oxide film and the silicon oxide film as heavy metal contamination in the manufacturing process of the field silicon oxide film and the silicon oxide film can be dispersed in the plurality of protrusions.

As a result, a small amount of iron is present in the convex portion of the field silicon oxide film around the semiconductor element, and this iron causes electrical characteristics of the semiconductor element such as the collector-emitter breakdown voltage of the npn transistor. It is possible to manufacture a semiconductor element having excellent electrical characteristics and to manufacture a semiconductor integrated circuit device with a high manufacturing yield.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is an embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of a semiconductor integrated circuit device which is another embodiment of the present invention.

FIG. 8 is a plan view showing a wafer used in a manufacturing process of a semiconductor integrated circuit device which is another embodiment of the present invention.

FIG. 9 is a graph showing the results of the study by the present inventor, which shows the manufacturing yield and the edge of the silicon oxide film serving as a field insulating film due to the collector-emitter breakdown voltage failure of the npn transistor in the semiconductor integrated circuit device. FIG. 6 is a graph showing the relationship with the iron concentration in the convex portion of the portion.

FIG. 10 is a graph showing the result of examination by the present inventor,
In the center of the wafer having the semiconductor region for manufacturing the semiconductor integrated circuit device, the orientation flat side, and the projections at the end portions of the silicon oxide film serving as the field insulating film on the top side opposite to the orientation flat side and the iron at those positions It is a graph which shows the relationship with a density.

[Explanation of symbols]

 1 semiconductor substrate 2 n-type semiconductor region 3 n-type semiconductor region 4 silicon nitride film 5 groove 6 field silicon oxide film 7 silicon oxide film 8 contact region 9 contact region 10 base region 11 emitter electrode 12 emitter region 13 silicon oxide film 14 wafer 15 Orientation flat part 16 Top part 17 Silicon oxide film

Claims (6)

[Claims] 1. A semiconductor integrated circuit device, wherein a plurality of protrusions similar to the protrusions at the ends of a field insulating film formed on a semiconductor substrate are provided inside the field insulating film. 2. The semiconductor integrated circuit device according to claim 1, wherein the field insulating film is a silicon oxide film having a LOCOS structure. 3. A step of forming a surface oxidation mask film in a plurality of selective regions of a semiconductor element formation region and a field insulating film formation region on a surface of a semiconductor region, and the step of using the surface oxidation mask film as a mask. By thermally oxidizing the semiconductor region and forming a silicon oxide film as a field insulating film on the surface of the semiconductor region, a convex portion similar to the convex portion formed at the end of the silicon oxide film is oxidized. A method of manufacturing a semiconductor integrated circuit device, comprising: a step of forming a plurality of layers inside a silicon film; and a step of forming a semiconductor element in a semiconductor element forming area of the semiconductor area. 4. A step of forming a mask film for surface oxidation on a semiconductor element forming region on the front surface of the semiconductor region and a plurality of selective regions on the back surface of the semiconductor region; and using the mask film for surface oxidation as a mask, Thermal oxidation treatment of the semiconductor region is performed to form a silicon oxide film to be a field insulating film on the surface of the semiconductor region, and at the end of the silicon oxide film when the silicon oxide film is formed on the back surface of the semiconductor region. A semiconductor integrated circuit comprising a step of forming a plurality of convex portions similar to the convex portions to be formed inside the silicon oxide film, and a step of forming a semiconductor element in the semiconductor element forming region of the semiconductor region. Device manufacturing method. 5. A step of forming a surface oxidation mask film on a semiconductor element formation region and a plurality of selective peripheral regions on a surface of a semiconductor region of a wafer, and the semiconductor using the surface oxidation mask film as a mask. A region is thermally oxidized to form a silicon oxide film to be a field insulating film on the surface of the semiconductor region, and an edge of the silicon oxide film when the silicon oxide film is formed on the peripheral portion of the semiconductor region of the wafer. A semiconductor having a step of forming a plurality of convex portions similar to the convex portions formed in the inner part of the silicon oxide film, and a step of forming a semiconductor element in the semiconductor element forming region of the semiconductor region. Manufacturing method of integrated circuit device. 6. The method of manufacturing a semiconductor integrated circuit device according to claim 3, 4, or 5, wherein the semiconductor element is formed in the semiconductor region separated from an end portion of the silicon oxide film serving as a field insulating film. A method of manufacturing a semiconductor integrated circuit device, comprising: