Browse Prior Art Database

Electroless Bath Stability Tester

IP.com Disclosure Number: IPCOM000043011D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kaschak, RA: AUTHOR [+2]

Abstract

Electroless copper plating baths are inherently unstable systems tending to plate onto any active surface, such as the vessel walls, piping and panel photoresist. Plating onto extraneous areas leads to bath instability from a control standpoint and higher defects, such as nodules. Bath stability over time can be measured, allowing bath stability to be quantified. This eliminates the need to discard and etch a bath on a routine basis. This testing method uses three coupons, each of a known surface area and surface roughness, that are always immersed in the plating vessel at the same point near the bottom of the vessel. One coupon will lie in a horizontal position, one in a vertical position, and one in a 45Πangle plane.

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Electroless Bath Stability Tester

Electroless copper plating baths are inherently unstable systems tending to plate onto any active surface, such as the vessel walls, piping and panel photoresist. Plating onto extraneous areas leads to bath instability from a control standpoint and higher defects, such as nodules. Bath stability over time can be measured, allowing bath stability to be quantified. This eliminates the need to discard and etch a bath on a routine basis. This testing method uses three coupons, each of a known surface area and surface roughness, that are always immersed in the plating vessel at the same point near the bottom of the vessel. One coupon will lie in a horizontal position, one in a vertical position, and one in a 45OE angle plane. The coupons will consist of either polypropylene (vessel wall composition), polyvinylchloride (piping composition), fully exposed photoresist on a laminate or a copper surface. The fully exposed resist coupons can be exposed with either clear or opaque MYLAR*. Since most of the undesirable plating that occurs in the plating vessel occurs near the bottom of the vessel, these coupons can be removed at periodic intervals and visually inspected. Based on this visual inspection, percent plating or nodule formation as a function of total surface area can be calculated and recorded. Monitoring the change in percent area plated and the size and distribution of nodules will be a function of bath stability. This will allow...