Damascene formation of borderless contact MOS transistors
First Claim
1. A method of making a semiconductor device comprising:
- providing a substrate;
forming a first dielectric layer over said substrate;
etching one or more openings in said first dielectric layer, wherein said openings define the location of MOS transistors;
depositing a material layer over said substrate to fill said openings;
pattering said material layer to define source and drain regions adjacent to a remaining portion of said material layer;
doping said source and drain regions with dopants;
depositing a second dielectric layer over said source and drain regions;
removing said remaining portion of said material layer to define a channel region in said substrate said channel region disposed between said source and drain regions;
depositing a third dielectric layer over said channel region to form a gate insulating layer;
etching contact openings over said source and drain regions;
forming contacts over said gate insulating layer and in said contact openings.
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Accused Products
Abstract
This invention is a processing method for forming MOS transistors. The method uses chemical mechanical polishing to self align an MOS transistor gate electrode to the channel region in both the width and length directions. The method enables metal interconnect lines to make borderless connections to MOS gate electrodes directly over channel regions, and allows borderless connections to be made to source and drain regions, thereby improving layout density of small transistors. The method enables interconnect lines to be patterned on a planar surface, which facilitates the etching of very narrow and closely spaced lines. The method does not require any Shallow Trench Isolation (STI), and does not require Local Oxidation of Silicon (LOCOS), thereby resulting in little damage to the silicon. The method also prevents plasma damage of very thin gate dielectrics during processing.
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Citations
20 Claims
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1. A method of making a semiconductor device comprising:
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providing a substrate; forming a first dielectric layer over said substrate; etching one or more openings in said first dielectric layer, wherein said openings define the location of MOS transistors; depositing a material layer over said substrate to fill said openings; pattering said material layer to define source and drain regions adjacent to a remaining portion of said material layer; doping said source and drain regions with dopants; depositing a second dielectric layer over said source and drain regions; removing said remaining portion of said material layer to define a channel region in said substrate said channel region disposed between said source and drain regions; depositing a third dielectric layer over said channel region to form a gate insulating layer; etching contact openings over said source and drain regions; forming contacts over said gate insulating layer and in said contact openings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for making a semiconductor device comprising:
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providing a substrate; forming a first dielectric layer over said substrate; forming a second dielectric layer over said substrate; etching one or more openings in said second dielectric layer wherein said openings define the location of MOS transistors; depositing a material layer over said substrate to fill said openings; removing said material layer except in said openings, patterning said material layer to define source and drain regions; implanting dopants through said first dielectric layer into said substrate to form source and drain regions; depositing a third dielectric layer in said openings, said third dielectric layer disposed above said source and drain regions; removing said pattered material layer; removing said first dielectric layer from a region disposed between said source and drain regions to define a channel region in said substrate; depositing a fourth dielectric layer over said channel region to form a gate insulting layer; activating and diffusing said dopants; depositing a first layer of TiN over said substrate; etching contact openings over said source and drain regions; depositing a layer of Ti over said substrate; depositing a second layer of TiN over said substrate; depositing a layer of tungsten over said contact openings and over said channel region; and patterning and isolating a conductive material over said insulating layer and said source and drain regions. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification