Method of making a negative photoresist image

• US 4,104,070 A
• Filed: 05/03/1976
• Issued: 08/01/1978
• Est. Priority Date: 06/30/1975
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Moritz, Holger, Paal, Gabor
• Primary Examiner(s): Bowers, Jr., Charles L.
• Application Number:
  US05/682,804
• Time in Patent Office: 820 Days
• Field of Search: 96/49, 96/36, 96/36.2, 96/33, 96/86 P, 96/91 D, 156/13, 156/14, 156/15, 427/43
• US Class Current: 430/329
• CPC Class Codes: G03F 7/0226 characterised by the non-macromolecular additives
• CPC Class Codes: G03F 7/085 Photosensitive compositions characterised by adhesion-promoting non-macromolecular additives G03F7/075 takes precedence
• CPC Class Codes: G03F 7/2022 Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
• CPC Class Codes: H01L 21/0274 Photolithographic processes

Abstract

The invention relates to a method of making a negative photoresist image on a substrate, where a normally positive working photoresist material containing 1-hydroxyethyl-2-alkyl-imidazoline is applied to a substrate, image-wise exposed with actinic radiation, heated, and blanket exposed to actinic radiation. The material which was not exposed originally is then removed with a solvent to give a negative image.

Claims

1. A method of making a negative photoresist image on a substrate consisting essentially of the steps of:

Applying to a substrate a layer of a positive working photoresist material consisting essentially of a phenolformaldehyde resin, a naphthoquinone (1,2) diazide sulfonic acid ester sensitizer, and a 1-hydroxyethyl-2-alkylimidazoline,

imagewise exposing the layer with actinic radiation,

heating the imagewise exposed layer for a sufficient period of time to a sufficient temperature to render the exposed areas insoluble in alkaline developer,

subsequently blanket exposing the layer with actinic radiation and, removing the portions of the layer which were not exposed during the imagewise exposure with an alkaline developer.

2. The method of claim 1 wherein the 1-hydroxyethyl-2-alkylimidazoline corresponds to the formula ##STR2## where R₁ represents a hydroxyethyl residue and R₂ an alkyl residue with 7 to 17 carbon atoms.

3. The method as of claim 2 wherein the alkyl residue contains 9 to 17 carbon atoms.

4. The method of claim 1, wherein the photoresist layer is heated to about 110°

C for approximately 10 to 20 minutes after the imagewise exposure.

5. The method of claim 4 wherein, after the thermal processing, the photoresist layer is blanket exposed until the sensitizer is degraded to about 10% of its original concentration.