안녕하세요 이디앤씨 입니다.
아래를 참고하시기 바랍니다.

The shapes available for the routing pad (first letter) are:
C - for Circle (Round)
S - for Square
A - for Annular (inner/outer diameters)
O - for Oval (Oblong)
R - for Rectangular
D - for Odd
N - for Nothing (Not Used)

The shapes available for the thermal pad (second letter) are:
C - for Circle (Round)
S - for Square
N - for Nothing (Not Used)

The shapes available for the antipad (third letter) are:
C - for Circle (Round)
S - for Square
N - for Nothing (Not Used)

감사합니다.