发明名称 |
Method for improving visibility of alignment targets in semiconductor processing |
摘要 |
Methods are disclosed that enhance the contrast between alignment targets and adjacent materials on a semiconductor wafer. According to a first embodiment, the TiN layer that is deposited during an earlier processing step is stripped away to enhance the reflectivity of the metal layer. According to a second embodiment, a reflective coating is added over the metal layer to enhance the reflectivity of the metal layer. According to a third embodiment, a reflective coating is added over the entire wafer to enhance the reflectivity of the metal layer. According to a fourth embodiment, an anti-reflective coating in a sandwich structure is added to reduce the reflectivity of the material adjacent the alignment targets. According to a fifth embodiment, an organic anti-reflective coating is added to reduce the reflectivity of the material adjacent the alignment targets. All of these embodiments result in a contrast between the alignment target and the adjacent material that is more consistent over variations in oxide thickness. The more uniform contrast makes it easier for the stepper system to identify the edges of the alignment targets, resulting in a more exact placement of the mask.
|
申请公布号 |
US5760483(A) |
申请公布日期 |
1998.06.02 |
申请号 |
US19960772709 |
申请日期 |
1996.12.23 |
申请人 |
INTERNATIONAL, BUSINESS MACHINES CORPORATION |
发明人 |
BRUCE, JAMES A.;HOLMES, STEVEN JOHN;LEIDY, ROBERT K. |
分类号 |
H01L23/544;(IPC1-7):H01L23/544 |
主分类号 |
H01L23/544 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|