Electrodeposition coating process of photoresist for printed circuit board

• US 4,898,656 A
• Filed: 03/28/1989
• Issued: 02/06/1990
• Est. Priority Date: 03/28/1988
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Kansai Paint Company Limited, Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kobayashi, Isao, Hoshino, Masahiro, Kondo, Toshio, Iwasawa, Naozumi, Seko, Kenji, Akaki, Yuu
• Primary Examiner(s): Tufariello, T. M.
• Application Number:
  US07/329,636
• Time in Patent Office: 315 Days
• Field of Search: 204/180.6, 204/181.1, 204/181.4
• US Class Current: 428/411.1
• CPC Class Codes: G03F 7/092 characterised by backside coating or layers, by lubricating-slip layers or means, by oxygen barrier layers or by stripping-release layers or means
• CPC Class Codes: G03F 7/164 using electric, electrostatic or magnetic means; powder coating
• CPC Class Codes: H05K 2203/0577 Double layer of resist having the same pattern
• CPC Class Codes: H05K 2203/135 Electrophoretic deposition of insulating material
• CPC Class Codes: H05K 3/0079 characterised by the method of application or removal of the mask H05K3/0091 takes precedence
• CPC Class Codes: H05K 3/064 Photoresists
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

An electrodeposition coating process of a photoresist for printed circuit board which comprises electrodeposition coating on a conductive surface a photosensitive electrodeposition coating composition (A), and thereafter further electrodeposition coating on the resultant coated plate an electrodeposition coating composition (B) composed chiefly of water-soluble or water-dispersible resin having a glass transition temperature (Tg) not lower than 20° C.

Claims

1. An electrodeposition coating process of a photoresist for printed circuit board which comprises electrodeposition coating on a conductive surface a photosensitive electrodeposition coating composition (A), and thereafter further electrodeposition coating on the resultant coated plate an electrodeposition coating composition (B) composed chiefly of water-soluble or water-dispersible resin having a glass transition temperature (Tg) not lower than 20°

C.

2. A process as defined in claim 1, in which the electrodeposition coating compositions (A) and (B) are negative type electrodeposition coating compositions containing as the chief ingredients water-soluble or water-dispersible polymerizable unsaturated resin and photo-polymerization initiator.

3. A process as defined in claim 2, in which the polymerizable unsaturated resin is an anionic or cationic resin having unsaturation equivalent of 150-3,000 and number average molecular weight of at least 300.

4. A process as defined in claim 3, in which the polymerizable unsaturated resin is an anionic resin formed by adding to a high acid value acrylic resin a compound containing in one molecule a polymerizable unsaturated bond and a glycidyl group.

5. A process as defined in claim 1, in which the electrodeposition coating compositions (A) and (B) are positive type electrodeposition coating compositions of which chief ingredients are water-soluble or waterdispersible resins containing photosensitive groups.

6. A process as defined in claim 5, in which the resin containing photosensitive groups contains, as the photosensitive groups, 5-60 wt % to the resin of benzoquinonediazide units or naphthoquinonediazide units.

7. A process as defined in claim 1, in which the electrodeposition coating composition (B) is composed chiefly of non-photocrosslinkable resin having no photosensitive groups.

8. A process as defined in claim 7, in which the non-photocrosslinkable resin containing no photosensitive groups is the polymerizable unsaturated resin from which polymerizable unsaturated groups have been removed.

9. A process as defined in claim 1, in which the resin used in the electrodeposition coating composition (A) has a glass transition temperature (Tg) of -50°

to 60°

C.

10. A process as defined in claim 1, in which the resin used in the electrodeposition coating composition (B) has a glass transition temperature (Tg) of from 40°

to 120°

C.

11. A process as defined in claim 1, in which Tg of the resin used for electrodeposition coating composition (B) is higher than that of the resin used for electrodeposition coating composition (A) by at least 5°

C.

12. A process as defined in claim 2, in which the film thicknesses of the coatings formed of the negative type electrodeposition coating compositions (A) and (B) are, respectively, 4-70μ

m and 0.5-30μ

m, and the total thickness of the two coatings is 5-70μ

m.

13. A process as defined in claim 5, in which the film thicknesses of the coatings formed of the positive type electrodeposition coating compositions (A) and (B) are, respectively, 2-50μ

m and 0.5-30μ

m, and the total thickness of the two coatings is 3-50μ

m.

14. A process as defined in claim 5, in which the positive type electrodeposition coating composition (B) is heat-treated after it is applied.

15. A process as defined in claim 14, in which the heat-treating conditions comprise surface temperature of 100°

to 180°

C. and heating time of from 1 second to 30 minutes.

16. Photoresist for printed circuit board electrodeposition coated by the claimed processes.