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Proceedings Paper

Characterization of an ultra-thick positive photoresist for electroplating applications
Author(s): Warren W. Flack; Ha-Ai Nguyen; Elliott Sean Capsuto
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Paper Abstract

The performance requirements for ultra-thick photoresists have increased rapidly with the dramatic growth in new lithographic applications that require electroplating processes. Two of the main applications for ultra-thick photoresists are nanotechnology (MEMS) and advanced packaging. Flipchip packaging has become widely adopted to address electrical device performance and chip form factor considerations. The growth in the nanotechnology market is driven by a wide range of products, which include accelerometers, ink jet print heads, biomedical sensors and optical switches. Electroplating levels for these applications require a photosensitive polymer material capable of coating, exposing and plating with conventional semiconductor equipment and standard ancillary process chemicals. A single coat step to achieve the final photoresist thickness is critical to minimize the number of process steps and cycle time. The sidewall profile, aspect ratio, electroplating durability and subsequent stripability are all important. This study characterized a novel positive photosensitive chemically amplified photoresist (ShinEtsu SIPR) for the use in a 65μm thick electroplating level on copper. The lithographic performance of the ultra-thick positive photoresist was optimized using a broad band, low numerical aperture, 1x stepper to control critical dimensions (CD), sidewall angles and aspect ratios. Cross sectional SEM analysis, contrast curves, process linearity, and process latitude plots were used to establish the lithographic capabilities. High aspect ratio structures were then electroplated using the optimized photoresist process to demonstrate photoresist durability and stripability. A recommended process flow is described for this photoresist and stepper.

Paper Details

Date Published: 12 June 2003
PDF: 15 pages
Proc. SPIE 5039, Advances in Resist Technology and Processing XX, (12 June 2003); doi: 10.1117/12.483748
Show Author Affiliations
Warren W. Flack, Ultratech Stepper, Inc. (United States)
Ha-Ai Nguyen, Ultratech Stepper, Inc. (United States)
Elliott Sean Capsuto, Shin-Etsu MicroSi, Inc. (United States)

Published in SPIE Proceedings Vol. 5039:
Advances in Resist Technology and Processing XX
Theodore H. Fedynyshyn, Editor(s)

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