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Laser Development of Latent Images

IP.com Disclosure Number: IPCOM000037322D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kreuter, V: AUTHOR [+3]

Abstract

This article describes a dry development process for lithographically produced latent images in a photoresist layer. This process comprises a silylation step which changes the optical properties of the unexposed regions, and a suitable laser floodlight exposure step.

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Laser Development of Latent Images

This article describes a dry development process for lithographically produced latent images in a photoresist layer. This process comprises a silylation step which changes the optical properties of the unexposed regions, and a suitable laser floodlight exposure step.

A process for producing RIE (reactive ion etch) and ion implantation resistant etch masks comprises the following steps: 1. standard photoresist exposure by UV photons,

electrons, ions or X-rays;

2. silylation (in the gas phase) followed by a bake

step;

3. laser ablation of the inverse latent image

(preferably in an O2 ambient).

Step 1 is a standard photolithographic process step. In step 2, silicon is included in the exposed regions of the resist surface. The subsequent bake step hardens the resist inside and outside the exposed regions. By including silicon in the exposed regions, the resist is changed such that the threshold for resist ablation is raised during pulsed laser radiation, whereas in the non-exposed regions, not including silicon, it remains unchanged.

By suitably selecting the energy density of the laser radiation, the non- silylated resist regions are attacked, i.e., chemically changed and ablated by the laser radiation, while the silylated regions remain unaffected. In this manner, the latent image can be developed by laser floodlight in step 3. As the regions exposed in step 1 are the finally remaining structures, this laser development of the lat...