Browse Prior Art Database

Process for Combining Sets of Masking Images

IP.com Disclosure Number: IPCOM000037550D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Polavarapu, MS: AUTHOR [+3]

Abstract

A process for reducing the required number of masking levels in a semiconductor device is disclosed. Multiple sets of images are exposed in one photoresist level. One set of images is fully developed while other sets are partially developed. Partially developed images are then fully developed at a later time as needed.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Process for Combining Sets of Masking Images

A process for reducing the required number of masking levels in a semiconductor device is disclosed. Multiple sets of images are exposed in one photoresist level. One set of images is fully developed while other sets are partially developed. Partially developed images are then fully developed at a later time as needed.

Referring to the example in the Figure, a wafer 1 is coated with photoresist 2. Reticle no. 1 is aligned, and the first set of images 3 is exposed so that the images will be fully developed. Next, reticle no. 2 is aligned, and the second set of images 4 is exposed at a fraction of the time used to expose the first set 3. The first set of images 3 is fully developed while the second set 4 is partially developed. Because of changes in the nature of partially exposed photoresist, the second set of images 4 can be fully developed at a later time (i.e., after a semiconductor etching process).

This process has advantages over separately exposing and developing images. It eliminates an entire masking level and reduces the amount of time required to form different images. It also reduces the amount of rework by lowering the probability of mistakes in the process.

Disclosed anonymously.

1