| 摘要 |
A method for manufacturing an image sensor is provided to enhance optical efficiency of the image sensor by selectively forming a metal capping layer for preventing copper being diffused only on a top surface of a copper wire. A first dielectric layer(207b) is formed on a semiconductor substrate(200) in which a light-receiving device(202) is provided. The first dielectric layer includes a lower copper wire(211) and a first metal capping layer(212a) formed thereon. A second and a third dielectric layers(207c,207d) are sequentially formed on the first dielectric layer. The third dielectric layer and the second dielectric layer which correspond to a portion of the first metal capping layer is etched by a predetermined thickness so that the second dielectric layer remains on the lower copper wire by a thickness of 100 to 3000 A to form a via hole(217). A predetermined portion of the third dielectric layer is further etched to form a trench(220) which is centered to the via hole and has a width broader than the via hole. The second dielectric layer exposed by the via hole is further etched. The via hole and the trench are filled up to form a via contact(221a) and an upper copper wire(221b), respectively. A second metal capping layer(212b) is selectively formed on a top surface of the upper copper wire.
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