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Optimization of Material Selection and Service Life of Polymer Membranes or Pellicles for Lithography Applications

IP.com Disclosure Number: IPCOM000042260D
Publication Date: 2005-Feb-03
Document File: 2 page(s) / 30K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a transparent and durable thin film, free-standing membrane that has conventional measurements and no special sample preparations. The disclosed method also uses non-destructive n and k measurements to uncover early signs of polymer pellicle degradation.

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Optimization of Material Selection and Service Life of Polymer Membranes or Pellicles for Lithography Applications

Disclosed is a method that uses a transparent and durable thin film, free-standing membrane that has conventional measurements and no special sample preparations. The disclosed method also uses non-destructive n and k measurements to uncover early signs of polymer pellicle degradation.

Background

There is a need to improve the quality of lithography processes that use polymer membranes to protect masks from contamination. Currently, the polymer membranes for lithography processes are thin film free-standing membranes that require tests to verify the optical properties of the membranes. Manufacturing these perfect thin film membranes is expensive, time-consuming, and requires in-depth knowledge of the process; only a few companies can manufacture polymer pellicles.

Currently, membrane failure is detected when the image resolution drops, or when the line width increases; pellicle wrinkling causes the pellicle to change prematurely and irreversibly before it reaches the end of its cycle. No early accurate detection of pellicle degradation exists. Also, the polymer membrane is often replaced after a certain exposure dosage, without measuring any pellicle degradation; this can lead to premature pellicle removal.

General Description

The disclosed method uses a transparent and durable thin film, free-standing membrane that has conventional measurements and no special sample preparations, as well as non-destructive n and k measurements to uncover early signs of polymer pellicle degradation.

The n and k tool measures reflectance, transmission, and the refractive index of a thin transparent...