Using principal component analysis for photomask CD signature investigations
Abstract
Reticle critical dimension (CD) errors must be minimized in order for photomask manufacturers to meet tight CD uniformity (CDU) requirements. Determining the source of reticle CD errors and reducing or eliminating their CDU contributions are some of the most relevant tasks facing process engineers. The AMTC has applied principal component analysis (PCA) to reticle resist CD measurements in order to examine variations in the data. PCA provided the major components of resist CD variation which were rescaled into reticle CD signatures. The dominant component of CD signature variation is very similar in shape and magnitude between two different chemically amplified resist (CAR) processes, most likely indicating the variation source is a common process or tool. CD variational signatures from PCA were used as a basis for launching investigations into potential reticle CD error sources. PCA was further applied to resist CD measurements from alternate process tools to assist efforts in judging the effectiveness of resist CD signature matching.
- Publication:
-
Photomask Technology 2010
- Pub Date:
- September 2010
- DOI:
- 10.1117/12.864139
- Bibcode:
- 2010SPIE.7823E..2OC