Claims
- 1. A method of manufacturing a semiconductor device, comprising the steps of:
- (a) preparing a first conductivity type semiconductor substrate;
- (b) selectively removing a surface of said semiconductor substrate to thereby provide said semiconductor substrate with a first region formed with a relatively high surface and a second region adjacent to the first region and formed with a relatively low surface;
- (c) forming a second conductivity type buried semiconductor layer of a relatively high impurity concentration with substantially uniform thickness formed on said semiconductor substrate in said first and second regions;
- (d) growing a second conductivity type epitaxial layer of a relatively low impurity concentration in substantially uniform thickness on said buried semiconductor layer; and
- (e) selectively removing said epitaxial layer in said first region to thereby equalize the height of a portion of the surface of said epitaxial layer in said first and second regions, and to provide said surface of said epitaxial layer with a concave or convex step in a boundary portion between said first and second regions.
- 2. A method of manufacturing a semiconductor device in accordance with claim 1, wherein
- said step (b) includes the steps of:
- forming a first mask in said first region;
- performing first selective oxidation using said first mask to form a first oxide film on said semiconductor substrate in said second region in order to make said semiconductor substrate thinner in said second region; and
- removing said first mask and said first oxide film.
- 3. A method of manufacturing a semiconductor device in accordance with claim 1, wherein
- said step (c) includes the steps of:
- introducing second conductivity type impurities into the surface of said semiconductor substrate; and
- diffusing said impurities to form said buried semiconductor layer.
- 4. A method of manufacturing a semiconductor device in accordance with claim 2, wherein
- said step (e) includes the steps of:
- forming a second mask in said second region;
- performing second selective oxidation using said second mask to form a second oxide film on said epitaxial layer in said first region in order to make said epitaxial layer thinner in said first region, and
- removing said second mask and said second oxide film.
- 5. A method of manufacturing a semiconductor device in accordance with claim 4, wherein
- said second mask has an edge set on the second region apart from the boundary portion between said first and second regions.
- 6. A method of manufacturing a semiconductor device in accordance with claim 4, wherein
- said second mask has an edge set on the first region apart from the boundary portion between said first and second regions.
- 7. A method of manufacturing a semiconductor device in accordance with claim 4, wherein
- said first and second selective oxidation steps are performed under the same condition.
- 8. A method of manufacturing a semiconductor device in accordance with claim 1, further comprising the step of:
- forming a plurality of trench isolating layers reaching said semiconductor substrate from the surface of said epitaxial layer to divide first and second regions into a plurality of element regions.
- 9. A method of manufacturing a semiconductor device in accordance with claim 8, wherein
- said step of forming a plurality of trench isolating layers is performed by using said concave or convex step as an alignment mark.
- 10. A method of manufacturing a semiconductor device in accordance with claim 8, further comprising the step of:
- forming transistors in predetermined ones of said plurality of element regions.
- 11. A method of manufacturing a semiconductor device in accordance with claim 1, wherein
- said step (b) includes the steps of:
- forming a first mask in said first region;
- performing first plasma etching using said first mask to make said semiconductor substrate thinner in said second region., and
- removing said first mask.
- 12. A method of manufacturing a semiconductor device in accordance with claim 11, wherein
- said step (e) includes the steps of:
- forming a second mask in said second region;
- performing second plasma etching using said second mask to make said epitaxial layer thinner in said first region; and
- removing said second mask.
- 13. A method of manufacturing a semiconductor device in accordance with claim 12, wherein
- said second mask has an edge set on the second region apart from the boundary portion between said first and second regions
- 14. A method of manufacturing a semiconductor device in accordance with claim 12, wherein
- said second mask has an edge set on the first region apart from the boundary portion between said first and second regions.
- 15. A method of manufacturing a semiconductor device in accordance with claim 12, wherein
- said first and second plasma etching steps are performed under the same condition.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2-301543 |
Nov 1990 |
JPX |
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Parent Case Info
This is a division of application Ser. No. 07/793,942, filed on Oct. 22, 1991, now U.S. Pat. No. 5,256,898.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4554726 |
Hillenius et al. |
Nov 1985 |
|
5134082 |
Kirchgessner |
Jul 1992 |
|
5225365 |
Cosentino |
Jul 1993 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
61-236155 |
Apr 1985 |
JPX |
3-227055 |
Oct 1991 |
JPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
793942 |
Oct 1991 |
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