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US 6,387,786 B1Granted
Method of salicide formation by siliciding a gate area prior to siliciding a source and drain area
AssigneeAdvanced Micro Devices, Inc.
InventorsJeff Erhardt, Eric Paton
Life of this patent
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Abstract
The present invention relates to a method of forming a self-aligned silicide (salicide) by siliciding a gate area prior to siliciding a source and drain area and/or spacer formation. The method improves transistor speed by lowering the leakage current in the source and drain areas and lowering the polysilicon sheet resistance of the gate. As a result of one embodiment of the present method, a silicide is formed over the gate area that is advantageously thicker than silicide formations over the source and drain areas.
Claims32
A method of forming a silicide, the method comprising:
- conformally forming a first metal layer over a gate area and a gate dielectric layer before forming spacers adjacent to the gate area, the gate dielectric layer covering a source area and a drain area;
- applying a first thermal anneal that causes the first metal layer to at least partially react with the gate area to form a first silicide layer over the gate area;
- removing any unreacted metal from the first metal layer over the gate dielectic layer;
- forming spacers adjacent to the gate area;
- removing the gate dielectric layer over the source and drain areas;
- forming a second metal layer over the first silicide layer and the source and drain areas;
- applying a second thermal anneal, wherein the second thermal anneal causes (1) the second metal layer to further react with the gate area to enhance the first silicide layer, and (2) the second metal layer to at least partially react with the source and drain areas to form second and third silicide layers;
- and
- removing any unreacted metal from the second metal layer.
6 more elements
A method of forming a silicide, the method comprising:
- conformally forming a first metal layer over a gate area and a gate dielectric layer, the gate dielectric layer covering a source area and a drain area;
- applying a fist thermal anneal that causes the first metal layer to at least partially react with the gate area to form a first silicide layer over the gate area;
- forming a capping layer over the first metal layer, wherein the first thermal anneal is applied before forming a capping layer over the first metal layer;
- removing any unreacted metal from the first metal layer over the gate dielectric layer;
- removing the gate dielectric layer over the source and drain areas;
- forming a second metal layer over the first silicide layer and the source and drain areas;
- applying a second thermal anneal, wherein the second thermal anneal causes (1) the second metal layer to further react with the gate area to enhance the first silicide layer, and (2) the second metal layer to at least partially react with the source and drain areas to form second and third silicide layers;
- and
- removing any unreacted metal from the second metal layer.
6 more elements
A method of forming a silicide, the method comprising:
- conformally forming a first metal layer over a gate area and a gate dielectric layer before forming spacers adjacent to the gate area, the gate dielectric layer covering a source area and a drain area;
- applying a first thermal anneal that causes the first metal layer to at least partially react with the gate area to form a first silicide layer over the gate area;
- removing any unreacted metal from the first metal layer over the gate dielectric layer;
- forming spacers adjacent to the gate area;
- removing the gate dielectric layer over the source and drain areas;
- forming a second metal layer over the first silicide layer and the source and drain areas;
- and
- applying a second thermal anneal, wherein the second thermal anneal causes (1) the second metal layer to further react with the gate area to enhance the first silicide layer, wherein the second thermal anneal causes substantially all of the second metal layer over the gate area to react with the gate area, and (2) the second metal layer to at least partially react with the source and drain areas to form second and third silicide layers.
5 more elements
Dependencies are inferred from the claim text.