반도체 공정 - Liftoff 공정에 대해

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반도체 공정의 하나인 Liftoff 공정에 대한 레포트 입니다.

목차

Liftoff process

Problems

Solution

Important Point

본문내용

Problems
1. If sidewalls are not perpendicular, the metal is likely to be continuous. There is no sepatation between the undesired and desired metal.
2. Metal on substrate doesn`t fall perfectly flat. Parts can also pile up and cling to the resist sidewalls. After the lift, unpredictable results will occur.
Solution
Create an overhang in the resit profile using chlorobenzene.
Soaking resist in chlorobenzene makes the resist harder, decreasing the development rate. Only the surface of the wafer is exposed to the chlorobenzene causing just the top layer of the resist to have a reduced development rate.
Important Point
- Resist Height
Except for conditions of very isotropic development, it is generally better to use a thicker resist. Using a thicker resist lowers the chances of the metal being continuous. However, if your development is more isotropic, then using a thicker resist requires a longer overhang
.

참고 자료

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