Self-aligned semiconductor contact structures and methods for fabricating the same
First Claim
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1. A method of forming a self-aligned contact comprising:
- forming gate electrodes that are spaced apart from each other on a semiconductor substrate;
forming a first liner layer on the semiconductor substrate and the gate electrodes;
forming an interlayer insulation layer over the first liner layer;
forming a contact window having opposing spaced apart sidewalls and a bottom by selectively etching the interlayer insulation layer with respect to the first liner layer;
forming a second liner layer over the interlayer insulation layer and the bottom and sidewalls of the contact window;
forming a buffer insulation layer to extend laterally a distance beyond the second liner layer to overhang in the contact window;
exposing the semiconductor substrate between adjacent gate electrodes by performing an etch back process to remove the buffer insulation layer and the second and first insulation layers at a bottom portion of the contact window; and
filling the contact window with conductive material to thereby substantially and/or entirely fill at least a lower portion of the contact window.
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Abstract
A self-aligned contact structure and a method of forming the same include selected neighboring gate electrodes with adjacent sidewalls that are configured to angle toward each other. The angled surfaces of the gate electrodes can be protected using a liner layer that can extend the length of the contact window to define the sidewalls of the contact window.
21 Citations
20 Claims
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1. A method of forming a self-aligned contact comprising:
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forming gate electrodes that are spaced apart from each other on a semiconductor substrate;
forming a first liner layer on the semiconductor substrate and the gate electrodes;
forming an interlayer insulation layer over the first liner layer;
forming a contact window having opposing spaced apart sidewalls and a bottom by selectively etching the interlayer insulation layer with respect to the first liner layer;
forming a second liner layer over the interlayer insulation layer and the bottom and sidewalls of the contact window;
forming a buffer insulation layer to extend laterally a distance beyond the second liner layer to overhang in the contact window;
exposing the semiconductor substrate between adjacent gate electrodes by performing an etch back process to remove the buffer insulation layer and the second and first insulation layers at a bottom portion of the contact window; and
filling the contact window with conductive material to thereby substantially and/or entirely fill at least a lower portion of the contact window. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of forming a self-aligned contact comprising:
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forming gate electrodes that are spaced apart from each other with a plurality of the gate electrodes positioned at a cell array region and at least one gate electrode positioned at a peripheral circuit region of the semiconductor substrate, respectively;
forming a first liner layer over the semiconductor substrate and surfaces of the gate electrodes;
forming a sacrificial insulation layer on the first liner layer in an amount sufficient to cover spaces between the gate electrodes of the cell array region;
etching back the sacrificial insulation layer so as to form temporary sidewall spacers on sidewalls of the at least one gate electrode at the peripheral circuit region;
forming a metal silicide layer at least on the semiconductor substrate exposed adjacent the temporary sidewall spacers;
thenremoving the sacrificial insulation layer remaining at the cell array region and the temporary sidewall spacers of the peripheral circuit region;
forming an interlayer insulation layer having a substantially planar top surface;
selectively etching the interlayer insulation layer with respect to the first liner layer to form at least one contact window in the cell array region between adjacent first and second gate electrodes, the contact window having opposing spaced apart sidewalls and a bottom;
forming a second liner layer on the sidewalls and bottom of the contact window;
forming a buffer insulation layer on the second liner layer so that the buffer insulation layer extends a lateral distance into the contact window to leave a gap space in the contact window, the buffer insulation layer having a greater thickness at a top portion of the sidewalls of the contact window than at a lower portion of the sidewalls of the contact window;
exposing the semiconductor substrate between the gate electrodes of the cell array region by performing an etch back process; and
filling at least a lower portion of the contact window with conductive material. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of forming a self-aligned contact window configured to hold a self-aligned contact pad therein in communication with a semiconductor substrate, comprising:
removing a selected portion of an interlayer insulation layer and then an underlying upper portion of adjacent sidewalls of first and second gate electrodes held proximate to each other on a semiconductor substrate to form first and second gate electrodes with sloped sidewalls that angle toward each other and define a portion of the shape of sidewalls of a self-aligned contact window configured to hold a self-aligned contact pad therein.
Specification