1results about How to "Avoid undercut" patented technology

The application discloses a metal line forming method of a CIS, which comprises the following steps: forming a hard mask layer on a first metal layer, the first metal layer being formed on a second metal layer; performing photoetching by using a pattern mask plate to form a first photoresist pattern on the hard mask layer, and the hard mask layer of a target area is exposed; performing first dry etching by taking the first photoresist pattern as a mask, etching to a predetermined depth in the hard mask layer of the target area, and the first photoresist pattern is removed after the first dry etching; performing photoetching by using the same pattern mask plate to form a second photoresist pattern on the remaining hard mask layer; and performing second dry etching by taking the second photoresist pattern and the remaining hard mask layer as masks until the second metal layer in the target area is exposed, and the reaction by-products generated by the second photoresist pattern protect the area of the first metal layer exposed by etching in the second dry etching process. The application is beneficial to avoiding the problem of lateral drilling of the bottom of the metal line under the condition of prolonged over-etching time.