This month we start a new 3 part series “Optical lithography for Thin Film Head (TFH) manufacturing”.

This series chronicles a number of historical lithographic milestones that were critical to the success of the TFH market’s growth and ability to continuously increase hard drive capacity at the lowest possible cost.

Part 1: "Imaging high aspect ratio features”

The Thin Film Head is one of the most successful MEMS devices ever built. In the late 1990’s TFH manufacturers were struggling with a technology node transition, from i-line (365nm) to DUV (248nm). How far could i-line resist processing be extended, especially for electroplating layers that required high aspect ratio imaging? Conventional i-line materials quickly ran out of steam for high aspect ratio imaging, so chemically amplified i-line resists were employed to extend this capability. However, with the development of new thick DUV resist materials, which had both the resolution and aspect ratio advantages, the move to DUV followed rapidly.

 

An interesting TFH presentation from ASML shows this in more detail, with some very nice SEM cross sections For more information on TFH processing and high aspect ratio imaging, please This e-mail address is being protected from spambots. You need JavaScript enabled to view it. at simaxlithography.com