Fin cut enabling single diffusion breaks
First Claim
1. A method for forming a diffusion break in a finned semiconductor structure, comprising:
- obtaining a finned semiconductor structure including a bulk semiconductor substrate including a substrate portion, a plurality of parallel fins extending from the substrate portion, a shallow trench isolation region, each of the fins including a top region extending above the shallow trench isolation region and a bottom region within the shallow trench isolation region, a plurality of parallel dummy gates extending over the fins and perpendicularly with respect to the fins, and spacers lining the dummy gates;
removing at least one of the dummy gates to form a space between a pair of the spacers and above at least a first of the parallel fins;
ion implanting the top region of the first fin to cause the formation of a top amorphous alloy fin region;
removing the top amorphous alloy fin region of the first fin using a chemical etch selective to the spacers, the shallow trench isolation region, and the substrate;
ion implanting a portion of the bottom region of the first fin following removing the top amorphous alloy fin region to cause the formation of a bottom amorphous alloy fin region, andremoving the bottom amorphous alloy fin region of the first fin using a chemical etch selective to the spacers, the shallow trench isolation region, and the substrate to form a recess within the shallow trench isolation region, the space and the recess forming a diffusion break cut region.
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Abstract
A method is provided for forming a fin cut that enables a single diffusion break in very dense CMOS structures formed using bulk semiconductor substrates. A dummy gate is removed from a finned structure to expose the top regions of the fins, the bottom fin regions being within a shallow trench isolation region. Selective vapor phase etching follows sequential ion implantation of the top and bottom fin regions to form a diffusion break cut region. The non-implanted regions of the substrate and the shallow trench isolation region remain substantially intact during each etching procedure. Double diffusion break cut regions are also enabled by the method.
48 Citations
20 Claims
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1. A method for forming a diffusion break in a finned semiconductor structure, comprising:
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obtaining a finned semiconductor structure including a bulk semiconductor substrate including a substrate portion, a plurality of parallel fins extending from the substrate portion, a shallow trench isolation region, each of the fins including a top region extending above the shallow trench isolation region and a bottom region within the shallow trench isolation region, a plurality of parallel dummy gates extending over the fins and perpendicularly with respect to the fins, and spacers lining the dummy gates; removing at least one of the dummy gates to form a space between a pair of the spacers and above at least a first of the parallel fins; ion implanting the top region of the first fin to cause the formation of a top amorphous alloy fin region; removing the top amorphous alloy fin region of the first fin using a chemical etch selective to the spacers, the shallow trench isolation region, and the substrate; ion implanting a portion of the bottom region of the first fin following removing the top amorphous alloy fin region to cause the formation of a bottom amorphous alloy fin region, and removing the bottom amorphous alloy fin region of the first fin using a chemical etch selective to the spacers, the shallow trench isolation region, and the substrate to form a recess within the shallow trench isolation region, the space and the recess forming a diffusion break cut region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification