Contact interface engineering for reducing contact resistance
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsMrunal A Khaderbad, Keng-Chu Lin, Sung-Li Wang
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Abstract
A structure includes a transistor including a first source/drain region, a source/drain contact plug over and electrically coupling to the first source/drain region, and a via over and contacting the source/drain contact plug. The via has a bottom portion having a first length, and an upper portion having a second length. The first length is greater than the second length. Both of the first length and the second length are measured in a same direction parallel to a top surface of the source/drain contact plug.
Claims20
A method comprising:
- depositing a first dielectric layer over a first conductive feature;
- depositing a second dielectric layer over the first dielectric layer;
- performing a first etching process to etch through the first dielectric layer and the second dielectric layer and to form an opening, wherein the opening comprises:
- a bottom portion in the first dielectric layer;
- and
- an upper portion in the second dielectric layer;
- after the first etching process, performing a tilt implantation process to implant sidewall portions of the first dielectric layer and the second dielectric layer, wherein the sidewall portions face the opening;
- after the tilt implantation process, performing a second etching process to expand the bottom portion, so that the bottom portion extends laterally beyond edges of the upper portion;
- and
- filling a conductive material into the opening to form a second conductive feature.
A method comprising:
- depositing a dielectric layer over a first conductive feature, wherein the depositing the dielectric layer comprises:
- depositing an etch stop layer;
- and
- depositing an inter-layer dielectric over the etch stop layer;
- etching through the dielectric layer to form an opening penetrating through the dielectric layer, wherein during the etching through the dielectric layer, the etch stop layer is used to stop etching of the inter-layer dielectric;
- expanding a bottom portion of the opening to be wider than a respective upper portion of the opening;
- and
- filling a conductive material into the opening to form a second conductive feature.
A method comprising:
- forming a first contact plug over and electrically coupling to a source/drain region;
- depositing an etch stop layer over the first contact plug;
- depositing a dielectric layer over the etch stop layer;
- forming an opening comprising a lower portion in the etch stop layer and an upper portion in the dielectric layer, so that a top surface of the first contact plug is revealed, wherein in a first cross-sectional view of the opening, first edges of the etch stop layer exposed to the lower portion are curved, and the lower portion has a first lateral dimension greater than a second lateral dimension of the upper portion, and wherein both of the first lateral dimension and the second lateral dimension are measured in a same first direction that is parallel to a top surface of the etch stop layer;
- and
- filling a conductive material into the opening to form a second contact plug.
Dependencies are inferred from the claim text.