Isolation for high density integrated circuits
First Claim
1. Method for forming a recessed isolation structure for an integrated circuit structure having substrate contacts comprising:
- forming a first masking layer over a major surface of a monocrystalline silicon substrate;
opening a pattern in said first masking layer to said major surface wherein said isolation structure is desired;
oxidizing the exposed monocrystalline substrate to produce said recessed isolation structure;
removing said first masking layer;
forming a second masking layer over said major surface;
opening a pattern in said second masking layer in the recessed isolation structure wherein said substrate contacts are to be formed;
forming through said opening a pattern of trenches having substantially vertical sidewalls through the said recessed isolation structure and into the said monocrystalline silicon thereunder;
forming an insulating layer upon the surfaces of said trenches;
removing said insulating layer from the bottom surfaces of said trenches;
depositing a layer of polycrystalline silicon over said substrate to fill said trenches; and
planarizing said major surface of said substrate by an etching process which substantially removes said layer of polycrystalline silicon except from said trenches.
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Accused Products
Abstract
An integrated circuit structure having substrate contacts formed as a part of the isolation structure and the method to form such structure is described. The integrated circuit structure is composed of a monocrystalline silicon body having a pattern of dielectric isolation surrounding regions of the monocrystalline silicon in the body. The dielectric isolation pattern includes a recessed dielectric portion at and just below the surface of the integrated circuit and a deep portion which extends through the recessed dielectric portion and extends further into the monocrystalline silicon body than the recessed portion. A highly doped polycrystalline silicon substrate contact is located within the deep portion of the pattern of isolation. The substrate contact extends from the surface of the pattern of isolation down to the bottom of the deep portion of the isolation where the contact electrically connects to the silicon body. Any of a variety of integrated circuit device structures may be incorporated within the monocrystalline silicon regions. These devices include bipolar transistors, field effect transistors, capacitors, diodes, resistors and the like.
138 Citations
11 Claims
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1. Method for forming a recessed isolation structure for an integrated circuit structure having substrate contacts comprising:
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forming a first masking layer over a major surface of a monocrystalline silicon substrate; opening a pattern in said first masking layer to said major surface wherein said isolation structure is desired; oxidizing the exposed monocrystalline substrate to produce said recessed isolation structure; removing said first masking layer; forming a second masking layer over said major surface; opening a pattern in said second masking layer in the recessed isolation structure wherein said substrate contacts are to be formed; forming through said opening a pattern of trenches having substantially vertical sidewalls through the said recessed isolation structure and into the said monocrystalline silicon thereunder; forming an insulating layer upon the surfaces of said trenches; removing said insulating layer from the bottom surfaces of said trenches; depositing a layer of polycrystalline silicon over said substrate to fill said trenches; and planarizing said major surface of said substrate by an etching process which substantially removes said layer of polycrystalline silicon except from said trenches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification