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Method for a SLURPP

IP.com Disclosure Number: IPCOM000019313D
Publication Date: 2003-Sep-10
Document File: 3 page(s) / 72K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a sealed chrome layer under the reticle for particle protection (SLURPP). Benefits include improved functionality and improved yield.

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Method for a SLURPP

Disclosed is a method for a sealed chrome layer under the reticle for particle protection (SLURPP). Benefits include improved functionality and improved yield.

Background

Particulates must be prevented from landing on the chrome surface of a photolithographic reticle. These particles can produce an image on the wafer and cause defects that reduce product yield.

Conventionally, a polymer membrane is suspended a certain distance below the chrome surface by means of a pellicle frame. The particles land on the pellicle instead of the chrome surface. As a result, the particles are sufficiently out of focus that they do not create an image at the wafer plane. However, some particles do land under the pellicle and attach to the chrome surface. A more effective solution is required (see Figure 1).

At an exposure wavelength of 157 nm, finding a polymer material for the pellicle that has the required lifetime is conventionally difficult. A hard pellicle suspends a plate of optical material below the reticle chrome surface. This solution may result in patterning degradation and optical distortion.

At exposure wavelengths of 248 and 193 nm, adhesives are used to attach the pellicle to the pellicle frame and attach the pellicle frame to the reticle. These adhesives and the pellicle material have the potential of releasing contaminants that can adhere to optical elements in the scanner and cause patterning degradation.

General description

The disclosed method adds additional optical material to the chrome side of a photolithographic reticle. Any particles landing on that side of the reticle meet the out-of-focus criteria for printable defects due to the thickness of the added material. As a result, a protective pellicle is not required.

         The key elements of the method include:

•         Additional processing steps in reticle manufacturing to add a layer of optical material to the chrome side of a reticle

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