Removal of Lift-Off Process Defects in Lithographic Mask Making
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Lithographic masks having very small lines and spaces can be manufactured by conventional lift-off processing. However, defects known as "skirts" and "fences" become more difficult to avoid as these lines and spaces decrease in size and as substrates increase in size. By depositing a film of a thickness greater than that required for opacity, removal of these defects is effected in a blanket etch process carried out after lift-off. The diagram shows the typical undercut edges 2 and 4 of photoresist 6 which define the metal line 8 deposited on the translucent substrate 10 in a conventional lift-off mask-making process. The photoresist 6 and the metal 14 which was deposited on top of the photoresist 6 are then removed in the lift-off process.