JPH08213450A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To provide a method for manufacturing a semiconductor device wherein the use of a mask is lessened when forming a semiconductor insular region and thereby an yield can be increased and the manufacturing cost can be reduced. CONSTITUTION: This method includes the steps of forming a silicon nitride film pattern 102 on one principal plane of a P-type semiconductor substrate 101 and then forming a selective oxide film 103 by selective oxidation using the silicon nitride film pattern 102 as a mask; introducing N-type impurities into the selective oxide film 103 being used as a mask; removing the selective oxide film 103 and then forming a P-type epitaxial film 105 in a region where the selective oxide film 103 has been removed; forming an oxide film 106 on the surface of the epitaxial film 105 and then removing the silicon nitride film pattern 102; and forming an N-type epitaxial film 107 from the oxide film 106 being used as a mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor island region of the semiconductor device.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, there were the following. 2A to 2D are cross-sectional views of manufacturing steps of a semiconductor island region of such a conventional semiconductor device. (1) First, as shown in FIG.
On the surface of the 0 Ωcm P-type semiconductor substrate 401, a silicon oxide film of about 0.5 μm is formed on the entire surface by thermal oxidation.
After that, a part thereof is removed by using a known photolithographic etching technique to form a silicon oxide film pattern 402. Subsequently, an N-type buried layer 403 having a sheet resistance of about 30Ω / □ is formed by ion (Sb) implantation and thermal diffusion.

At this time, the silicon oxide film pattern 402
The N-type buried layer 403 is not generated in the area where the remaining area. (2) Next, as shown in FIG. 2B, the silicon oxide film pattern 402 is completely removed, and a silicon oxide film of about 0.1 μm is formed by, for example, the CVD method. Then, a part of the silicon oxide film is removed by a known photolithographic etching technique to form a silicon oxide film pattern 404. After that, the surface is thermally oxidized (not shown),
A P-type buried layer 405 having a sheet resistance of about 4 kΩ / □
It is formed by ion implantation and thermal diffusion.

(3) Next, as shown in FIG. 2C, the silicon oxide film pattern 404 is completely removed.
An N-type epitaxial layer 406 having a specific resistance of 0.5 Ωcm and a film thickness of 1 μm is formed. After that, the N-type epitaxial layer 4
A silicon oxide film 407 is formed on the 06 surface by thermal oxidation. After that, a part thereof is removed by a known photolithography etching technique, and a P-type well layer 408 having a sheet resistance of about 3 kΩ / □ is formed at the opened place.

Thereafter, heat treatment is applied to the P-type well layer 40.
8 is diffused and connected to the P-type buried layer 405 which is the lower layer.

[0006]

However, in the conventional method for manufacturing the semiconductor island region of the semiconductor device described above,
Since three masks are used, there are problems that the process is long, the yield is reduced, and the manufacturing cost is increased. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a semiconductor device, which eliminates the conventional problems, reduces the use of a mask in forming a semiconductor island region, improves the yield, and can reduce the manufacturing cost. .

[0007]

In order to achieve the above object, the present invention provides [A] a method for manufacturing a semiconductor element, wherein an oxidation resistance is provided on one main surface of a first conductivity type semiconductor substrate (101). Membrane (102)
And removing a part thereof, forming a selective oxide film (103) by selective oxidation using the oxidation resistant film (102) as a mask, and the selective oxide film (10).
Using 3) as a mask, introducing impurities of the second conductivity type,
The step of forming a buried layer (104) and the removal of the selective oxide film (103), and a first step is applied only to the removed portion.
A conductive type epitaxial film (105) is formed, an oxide film (106) is formed on the surface of the epitaxial film (105), and then the oxidation resistant film (10) is formed.
2) is removed, and a step of forming an epitaxial film (107) of the second conductivity type is performed by using the oxide film (106) as a mask.

[B] In the method of manufacturing a semiconductor device described in [A] above, after the step (f), impurities of the second conductivity type are further formed on the entire surface of the second conductivity type epitaxial film (107). And a step of introducing an oxide film (20
8), a step of removing a part of the oxide film (208), and a step of forming an epitaxial film (209) of the first conductivity type in the opened portion of the oxide film (208). It is designed to be applied.

[C] In the method of manufacturing a semiconductor element, an oxidation resistant film (302) coated with a resist is formed on one main surface of a semiconductor substrate (301) of the first conductivity type, and a part thereof is removed. And an oxidation resistant film (302) coated with the resist is used as a mask to form a second conductivity type buried layer (308) by ion implantation, and the oxidation resistant film (302) is used as a mask. Forming a selective oxide film (303) by selective oxidation, introducing a second conductive type impurity using the selective oxide film (303) as a mask, and removing the selective oxide film (303) Then, a step of forming an epitaxial film (305) of the first conductivity type only on the removed portion, an oxide film (306) is formed on the surface of the epitaxial film (305), and then the oxidation resistance is applied. Membrane 302), a step of forming a second conductive type epitaxial film (307) by using the oxide film (306) as a mask, and an entire surface of the second conductive type epitaxial film (307). A step of introducing a second conductivity type impurity into the oxide film, and an oxide film (30
9), a step of removing a part of the oxide film (309), and a step of forming a first conductivity type epitaxial film (310) in the opened portion of the oxide film (309). It is designed to be applied.

[0010]

[Action]

(1) According to the method of manufacturing a semiconductor element of claim 1,
Conventionally, three masks have been required, but the semiconductor island region of the semiconductor element can be formed by using only one mask, the manufacturing is easy, the yield is improved, and the manufacturing cost is reduced. It can be reduced.

(2) According to the method of manufacturing a semiconductor element of claim 2, in addition to the above (1), by additionally stacking a P-type epitaxial film, the groove at the substrate contact portion is filled and the step is eliminated. be able to. (3) According to the method of manufacturing a semiconductor element of claim 3,
The presence of the N-type buried layer electrically insulates the P-type semiconductor island from other islands, and each island can be used as a complementary semiconductor island.

Particularly when applied to the above (2), it is possible to form a P-type island region having a high-concentration P-type buried layer, and a high-performance PNP transistor using this island region can be obtained.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view of a semiconductor device manufacturing process showing a first embodiment of the present invention. (1) First, as shown in FIG. 1A, a silicon nitride film is formed on the surface of the P-type semiconductor substrate 101 by, for example, the CVD method. Then, a part of the silicon nitride film is removed by a known photolithographic etching technique to form a silicon nitride film pattern 102.

(2) Next, as shown in FIG. 1B, for example, thermal oxidation is performed in a water vapor atmosphere at 1100 ° C., and the silicon oxide film 103 having a thickness of about 0.8 μm is selectively formed in the opened portion. To form. Then, a known ion implantation technique is used to form the N-type buried layer 104. At this time, the N-type buried layer 104 is not formed where the silicon oxide film 103 exists.

(3) Next, as shown in FIG.
The silicon oxide film 103 is completely removed by wet etching. Then, a P-type epitaxial film 105 is selectively formed to a thickness of about 1.0 μm in the opened portion by using a known selective epitaxial technique. Then, a silicon oxide film 106 is formed on the surface of the P-type epitaxial film 105 by thermal oxidation.

(4) Next, as shown in FIG. 1D, the silicon nitride film pattern 102 is removed by hot phosphoric acid.
Next, the N-type epitaxial film 107 is grown using a known selective epitaxial technique. At this time, the N-type epitaxial film 107 is not formed in the portion where the silicon oxide film 106 is formed, and the N-type buried layer 104 is formed.
The N-type epitaxial film 107 is formed only on the top.

With this structure, the semiconductor island region of the semiconductor element can be easily formed by using only one mask used only in the step of FIG. 1 (a). Next, a second embodiment of the present invention will be described. FIG. 3 is a sectional view of a semiconductor device manufacturing process showing a second embodiment of the present invention.

(1) First, as shown in FIG. 3 (a), the steps from FIG. 1 (a) to FIG. 1 (d) of the first embodiment are performed, and then, for example, As, 20 to 50 keV. , 1E1
When ion implantation is performed using an ion implantation technique of about ² ions / cm ² , As ions are implanted near the surface of the N-type epitaxial film 207. At this time, As ions stop in the silicon oxide film 206 and are not ion-implanted in the P-type epitaxial film 205. Note that 201
Is a P-type semiconductor substrate, and 204 is an N-type buried layer.

(2) Next, as shown in FIG.
When wet oxidation is performed at 50 to 950 ° C. for 30 minutes, the N-type epitaxial film 207 and the P-type epitaxial film 2 are formed.
A silicon oxide film 208 is formed on 05. At this time, the film thickness of the silicon oxide film 208 is different between the P-type epitaxial film 205 and the N-type epitaxial film 207.

(3) Next, as shown in FIG. 3C, a P-type epitaxial film 205 is formed by wet etching.
The upper silicon oxide film 208 is removed. At this time, the silicon oxide film 208 on the N-type epitaxial film 207 is
Since the film thickness is different, it is not completely removed and remains.
Then, a P-type epitaxial film 209 is formed in the opened portion.
Grow selectively. Then, the silicon oxide film 208 on the N-type epitaxial film 207 is removed.

With this structure, in addition to the first embodiment, the P-type epitaxial film 209 is additionally stacked to fill the groove in the substrate contact portion.
Steps can be eliminated. Next, a third embodiment of the present invention will be described. FIG. 4 is a sectional view (No. 1) of manufacturing steps of a semiconductor device showing the third embodiment of the present invention, and FIG. 5 is a sectional view (No. 2) of manufacturing steps of the semiconductor element.

(1) First, as shown in FIG. 4A, similar to the step of FIG. 1A of the first embodiment, the P-type semiconductor substrate 3 is formed.
A silicon nitride film is formed on the surface of 01 by the CVD method, for example. Then, apply resist 302A,
A part of the silicon nitride film coated with the resist is removed by a known photolithographic etching technique to form a silicon nitride film pattern 302 coated with the resist 302A. Then, using the silicon nitride film pattern 302 coated with the resist 302A as a mask, antimony is implanted at about 100 keV and about 1E15 ions / cm ² using a conventional ion implantation technique to form an N-type buried layer 308.

(2) Then, as shown in FIG.
For example, thermal oxidation is performed in a water vapor atmosphere at 1100 ° C., and a silicon oxide film 303 having a thickness of about 0.8 μm is selectively formed in the opened portion. Then, a known ion implantation technique is used to form the N-type buried layer 304. At this time,
The N-type buried layer 304 is not formed where the silicon oxide film 303 exists.

(3) Then, as shown in FIG.
The silicon oxide film 303 is completely removed by wet etching. Then, a P-type epitaxial film 305 is selectively formed to a thickness of about 1.0 μm in the opened portion by using a known selective epitaxial technique. Then, a silicon oxide film 306 is formed on the surface of the P-type epitaxial film 305 by thermal oxidation.

(4) Next, as shown in FIG. 4D, the silicon nitride film pattern 302 is removed by hot phosphoric acid.
Next, the N-type epitaxial film 307 is grown by using a known selective epitaxial technique. At this time, the N-type epitaxial film 307 is not formed in the portion where the silicon oxide film 306 is formed, and the N-type buried layer 304 is formed.
The N-type epitaxial film 307 is formed only on the top.

(5) Next, as shown in FIG. 5A, for example, As, 20 to 50 keV, 1E12ions / c
When ion implantation is performed using an ion implantation technique of about m ² , As ions are implanted near the surface of the N-type epitaxial film 307. At this time, As ions stop in the silicon oxide film 306, and the P-type epitaxial film 305 is formed.
Ions are not implanted inside.

(6) Next, as shown in FIG.
When wet oxidation is performed at 50 to 950 ° C. for 30 minutes, the N-type epitaxial film 307 and the P-type epitaxial film 3 are formed.
A silicon oxide film 309 is formed on 05. At this time, the film thickness of the silicon oxide film 309 differs between the P-type epitaxial film 305 and the N-type epitaxial film 307.

(7) Next, as shown in FIG. 5C, a P-type epitaxial film 305 is formed by wet etching.
The upper silicon oxide film 309 is removed. At this time, the silicon oxide film 309 on the N-type epitaxial film 307 is
Since the film thickness is different, it is not completely removed and remains.
Then, the P-type epitaxial film 310 is formed in the opened portion.
Grow selectively. After that, the oxide film on the N-type epitaxial film 307 is removed.

With this structure, the semiconductor island regions thus formed are electrically insulated from the substrate by the N-type buried layer 308. Therefore, the presence of the N-type buried layer 308 electrically insulates the P-type semiconductor island from the other islands, and each island can be used as a complementary semiconductor island. .

In particular, when applied to the second embodiment, a high concentration P-type buried is introduced by introducing a high concentration P-type impurity into the epitaxial film 205 and making the P-type epitaxial film 209 a low-concentration P-type epitaxial layer. It is possible to form a P-type island region having layers, and there is a great merit that a high performance PNP transistor using this island region can be realized.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0032]

【The invention's effect】

(1) According to the invention as set forth in claim 1, conventionally, three masks are required, but the semiconductor island region of the semiconductor element can be formed by using only one mask, and the manufacturing is easy. It is easy, yield can be improved, and manufacturing cost can be reduced.

(2) According to the second aspect of the present invention, by adding a P-type epitaxial film to the invention of the above (1), the groove at the substrate contact portion can be filled and the step can be eliminated. . (3) According to the invention as set forth in claim 3, the presence of the N-type buried layer electrically insulates the island of the P-type semiconductor from other islands, and each island is made of a complementary semiconductor. Can be used as an island.

In particular, when applied to the invention of (2) above,
A P-type island region having a high-concentration P-type buried layer can be formed, and a high-performance PNP transistor using this island region can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device in a manufacturing process showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a manufacturing process of a semiconductor island region of a conventional semiconductor device.

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

FIG. 4 is a manufacturing process sectional view (1) of a semiconductor device according to a third embodiment of the present invention.

FIG. 5 is a manufacturing process sectional view (2) of the semiconductor device according to the third embodiment of the present invention.

[Explanation of symbols]

101, 201, 301 P-type semiconductor substrate 102, 302 Silicon nitride film pattern 103, 106, 206, 208, 303, 306, 3
09 silicon oxide film 104, 204, 304, 308 N-type buried layer 105, 205, 209, 305, 310 P-type epitaxial film 107, 207, 307 N-type epitaxial film 302A Resist

Claims (3)

[Claims] 1. A semiconductor substrate (10) of the first conductivity type.
1) a step of forming an oxidation resistant film (102) on one main surface and removing a part thereof, (b) the oxidation resistant film (102)
Selective oxide film (103)
And (c) using the selective oxide film (103) as a mask to introduce impurities of the second conductivity type to form a buried layer (104), and (d) the selective oxide film ( 103) is removed, and only the removed part is
And (e) an oxide film (106) is formed on the surface of the epitaxial film (105), and then the oxidation resistant film (1) is formed.
02), and (f) the oxide film (106).
Using as a mask, the second conductivity type epitaxial film (1
07) is formed. 2. The method for manufacturing a semiconductor device according to claim 1, wherein after the step (f), (a) an impurity of a second conductivity type is formed on the entire surface of the epitaxial film (107) of the second conductivity type. Introducing step and (b) oxide film (20
8), a step of (c) removing a part of the oxide film (208), and (d) an epitaxial film of a first conductivity type () in the opened portion of the oxide film (208). Two
09) to form a semiconductor device. 3. A semiconductor substrate (30) of the first conductivity type (a)
1) An oxidation resistant film (30) having a main surface coated with a resist
2) and removing a part thereof, and (b) ion-implanting the buried layer (30) of the second conductivity type by using the oxidation resistant film (302) coated with the resist as a mask.
8) and forming a selective oxide film (303) by selective oxidation using the oxidation resistant film (302) as a mask, and (c) using the selective oxide film (303) as a mask. Introducing a second conductivity type impurity;
(D) The selective oxide film (303) is removed, and the first conductivity type epitaxial film (30) is formed only on the removed portion.
5), and (e) forming an oxide film (306) on the surface of the epitaxial film (305) and subsequently removing the oxidation resistant film (302).
(F) a step of forming an epitaxial film (307) of the second conductivity type by using the oxide film (306) as a mask,
(G) The second conductivity type epitaxial film (307)
A step of introducing impurities of the second conductivity type into the entire surface of
(H) a step of forming an oxide film (309) on the entire surface,
(I) a step of removing a part of the oxide film (309),
(J) A step of forming a first conductivity type epitaxial film (310) on the opened portion of the oxide film (309).