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Multilayered Thick Photoresist Mask for High Energy Ion Implants

IP.com Disclosure Number: IPCOM000078540D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Dolgov, I: AUTHOR [+4]

Abstract

A multilayered coating of photoresist comprising a first layer of positive photoresist, a second layer of polyvinyl alcohol, and a third layer of positive photoresist can be made thick enough to mask high, energy ions while preserving the advantages of photoresist processing, in contrast to the use of oxide or metal ion implantation masking.

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Multilayered Thick Photoresist Mask for High Energy Ion Implants

A multilayered coating of photoresist comprising a first layer of positive photoresist, a second layer of polyvinyl alcohol, and a third layer of positive photoresist can be made thick enough to mask high, energy ions while preserving the advantages of photoresist processing, in contrast to the use of oxide or metal ion implantation masking.

A coating of positive resist material, such as AZ-1350H*, is applied to a substrate using conventional techniques. After postbake, a coating of polyvinyl alcohol (PVA) solution is dynamically applied (2.5 grams per 100 milliliters of deionized water), spinning at 3500 rpm for 40 seconds. The PVA coating is baked at 85 degrees C for 10 minutes. A second coating of positive resist material is applied to the PVA coating in the conventional manner.

The selective exposure of the composite resist to form the desired masking patterns may be accomplished, either in one step (after the second application of positive photoresist) or in two separate steps (after each application of positive photoresist). In the former case, light energy of approximately 100-150 milliwatts-seconds per centimeter squared is satisfactory. In the latter case, 50 milliwatts-seconds per centimeter squared may be used for each exposure.

The PVA interlayer provides good adhesion between the two positive resist material layers and exhibits limited permeability with respect to the positive resist de...