Browse Prior Art Database

Improved Pumice Slurry Dispensing System

IP.com Disclosure Number: IPCOM000050079D
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Hume, DW: AUTHOR [+2]

Abstract

Circuitization of printed circuit boards is achieved through additive plating. The process sequence involves pumice scrubbing of the panels to provide a clean and slightly roughed surface for good photoresist adhesion.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Improved Pumice Slurry Dispensing System

Circuitization of printed circuit boards is achieved through additive plating. The process sequence involves pumice scrubbing of the panels to provide a clean and slightly roughed surface for good photoresist adhesion.

As shown in Figs. 1 and 2, pumice slurry is pumped from a supply tank through a manifold containing three openings onto a rotating brush. Because of the continuous direct impingement of the slurry on the brush in the three areas directly opposite the manifold's orifice, the brush in that area becomes soft and loses the scrubbing action. Visual inspection of the scrubbed panels shows three distinct ribbon like areas on the panel corresponding to the position of the three orifices in the manifold. These three areas appear to be smooth and shiny. In the subsequent photo process, the photoresist displays poor adhesion to the panel in those three areas.

This results in resist undercutting during additive plating.

Referring to Fig. 3, it is proposed to improve the slurry dispensing system and eliminate the above mentioned problems by employing a bracket which holds a piece of neoprene rubber and which is located between the slurry spray unit and the brush. This new system affords a more uniform distribution of the slurry over the panel and prevents the brush from being damaged by directing the slurry to the base of the brush and right onto the panel.

1

Page 2 of 2

2

[This page contains 4 pictures or other non-text...