Stacked interconnect structure between copper lines of a semiconductor circuit
First Claim
1. A method of forming an interconnect between a first layer copper line and a second layer copper line of a semiconductor circuit, said method comprising:
- forming a via through a first dielectric layer to expose the surface of the first layer copper line;
depositing a first barrier layer over inner sidewall and bottom surfaces of the via, the barrier layer providing a diffusion barrier against copper;
etching selectively the bottom surface of the via to substantially eliminate the barrier layer from the bottom surface; and
depositing a second barrier layer over the inner surfaces of the via, the second barrier layer providing a diffusion barrier against copper and ensures sufficient wettability of copper.
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Abstract
A stacked interconnect structure to connect a first layer copper line with a second layer copper line and method of making the same includes depositing a barrier layer over the inner surfaces of a via extending through a first dielectric layer between the first and second layer copper lines. The first barrier layer provides a barrier to copper diffusion into the dielectric layer. The first barrier layer is then selectively etched from the bottom surface of the via, after which a second barrier layer is deposited over the vertical and bottom surfaces of the via. The second barrier layer also provides a barrier to the diffusion of copper, but is less resistive than the first barrier, and ensure wettability of the copper.
29 Citations
21 Claims
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1. A method of forming an interconnect between a first layer copper line and a second layer copper line of a semiconductor circuit, said method comprising:
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forming a via through a first dielectric layer to expose the surface of the first layer copper line;
depositing a first barrier layer over inner sidewall and bottom surfaces of the via, the barrier layer providing a diffusion barrier against copper;
etching selectively the bottom surface of the via to substantially eliminate the barrier layer from the bottom surface; and
depositing a second barrier layer over the inner surfaces of the via, the second barrier layer providing a diffusion barrier against copper and ensures sufficient wettability of copper. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A stacked interconnect structure for coupling a first layer copper line with a second layer copper line comprising:
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a via extending through a first dielectric layer to expose the surface of the first layer copper line, the via having an inner core comprising copper;
a first barrier layer covering substantially vertical and bottom surfaces of the inner core; and
a second barrier layer substantially covering the vertical surfaces and not the bottom surface of the via, the second barrier layer lying between the first barrier layer and the first dielectric layer; and
wherein the second barrier layer provides a diffusion barrier against copper and the first barrier layer provides a barrier to copper, ensures wettability of the copper, and is relatively lower in resistivity than the second barrier layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification