Multi-patterning to form vias with straight profiles

    公开(公告)号:US11049763B2

    公开(公告)日:2021-06-29

    申请号:US16694406

    申请日:2019-11-25

    IPC分类号: H01L21/768 H01L21/311

    摘要: A method includes forming a carbon-containing layer with a carbon atomic percentage greater than about 25 percent over a first hard mask layer, forming a capping layer over the carbon-containing layer, forming a first photo resist over the capping layer, and etching the capping layer and the carbon-containing layer using the first photo resist as a first etching mask. The first photo resist is then removed. A second photo resist is formed over the capping layer. The capping layer and the carbon-containing layer are etched using the second photo resist as a second etching mask. The second photo resist is removed. A third photo resist under the carbon-containing layer is etched using the carbon-containing layer as etching mask. A dielectric layer underlying the third photo resist is etched to form via openings using the third photo resist as etching mask. The via openings are filled with a conductive material.