US5460984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a semi conductor device having a second well formed within a first well
Assignee: Toshiba Corp
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Filing: 1990-09-10
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Granted: 1995-10-24
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Expires: 2010-09-10
Abstract
Abstract A method of manufacturing a semiconductor device including the steps of: forming an oxide film on the surface of a semiconductor substrate, and thereafter injecting ions of a first conductivity type on the entire surface of the semiconductor substrate; forming a first well through a first thermal diffusion; injecting ions of a second conductivity type through the oxide film into a second well region within the first well; and removing the oxide film formed on the second well region, and thereafter forming a second well having a depth smaller than that of the first well. The semiconductor device manufactured by this method has a first well of a first conductivity type formed on the entire surface of a semiconductor substrate and having higher impurity concentration than that of the semiconductor substrate and a second well of a second conductivity type opposite to said first conductivity type formed within a desired region of said first well. The depth of said first well which is suitable for forming trench capacitors is greater than that of said second well.
Inventors
- 👤 Tohru Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:57
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10D84/859; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0191; H10D84/02; H10D84/03; H10D84/038; Y; Y10; Y10S; Y10S148/00; Y10S148/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
176 words
A method of manufacturing a semiconductor device comprising the steps of: forming an oxide film on the surface of a bulk semiconductor substrate, and thereafter injecting ions of a p-type over the entire surface of said bulk semiconductor substrate; performing a first heat treatment for forming a first well through a first thermal diffusion for activating said ions of the p-type; forming a mask layer on the oxide film, said mask layer having an aperture corresponding to a second well region where a second well is to be formed within said first well; injecting ions of an n-type through said oxide film into the second well region; removing said mask layer and said oxide film formed on said second well region; and performing a second heat treatment for diffusing said ions of the n-type to form a second well having a depth smaller than that of said first well and to form an oxide film on said second well which has a step-wise alignment mark at the boundary between said first well and said second well.
Claim 2
Independent Claim
176 words
A method of manufacturing a semiconductor device comprising the steps of: forming an oxide film on the surface of a bulk semiconductor substrate, and thereafter injecting ions of a p-type over the entire surface of said bulk semiconductor substrate; performing a first heat treatment for forming a first well through a first thermal diffusion for activating said ions of the p-type; forming a mask layer on the oxide film, said mask layer having an aperture corresponding to a second well region where a second well is to be formed within said first well; injecting ions of an n-type through said oxide film into the second well region; removing said mask layer and said oxide film formed on said second well region; and performing a second heat treatment for diffusing said ions of the n-type to form a second well having a depth smaller than that of said first well and to form an oxide film on said second well which has a step-wise alignment mark at the boundary between said first well and said second well.
Claim 3
Independent Claim
155 words
A method of manufacturing a semiconductor device comprising the steps of: forming an oxide film on the surface of a bulk semiconductor substrate, and thereafter injecting ions of a p-type over the entire surface of said bulk semiconductor substrate; forming a mask layer on the oxide film, said mask layer having an aperture corresponding to a predetermined region; selectively injecting ions of an n-type into said predetermined region, and injection depth of said n-type ions being shallower than that of said p-type ions; removing said mask layer and said oxide film formed on the surface of said predetermined region; and performing heat treatment for forming a first well of said p-type and a second well of said n-type within said first well by activating said p-type and n-type ions and forming an oxide film on said second well which has a step-wise alignment mark at the boundary between said first well and said second well.
Claim 4
Independent Claim
155 words
A method of manufacturing a semiconductor device comprising the steps of: forming an oxide film on the surface of a bulk semiconductor substrate, and thereafter injecting ions of a p-type over the entire surface of said bulk semiconductor substrate; forming a mask layer on the oxide film, said mask layer having an aperture corresponding to a predetermined region; selectively injecting ions of an n-type into said predetermined region, and injection depth of said n-type ions being shallower than that of said p-type ions; removing said mask layer and said oxide film formed on the surface of said predetermined region; and performing heat treatment for forming a first well of said p-type and a second well of said n-type within said first well by activating said p-type and n-type ions and forming an oxide film on said second well which has a step-wise alignment mark at the boundary between said first well and said second well.
Claim 5
Dependent Claim
41 words
A method of manufacturing a semiconductor device as claimed in claim 2, wherein the steps are repeated to form a third well within the second well, the third well being shallower in depth than the second well and having p-type ions.
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| 3.5 Years (Year 4) | 1998-10-23 | 1999-04-24 | 1999-10-24 | $2000.00 | Window Closed / Lapsed |
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