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Plating Through Holes

IP.com Disclosure Number: IPCOM000092824D
Original Publication Date: 1967-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Romankiw, LT: AUTHOR [+2]

Abstract

The interior surfaces of hollow objects, for example, substrates having a plurality of small through holes or long tubular objects having a very large length to diameter ratio L/d, are uniformly, electrolessly plated by the application of a pressure differential across the object to be plated. The pressure differential allows for the continuous and uniform flow of sensitizing, activating, and plating solutions through the hollow object. In the remainder of the article, the single word object is used in lieu of hollow object.

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Plating Through Holes

The interior surfaces of hollow objects, for example, substrates having a plurality of small through holes or long tubular objects having a very large length to diameter ratio L/d, are uniformly, electrolessly plated by the application of a pressure differential across the object to be plated. The pressure differential allows for the continuous and uniform flow of sensitizing, activating, and plating solutions through the hollow object. In the remainder of the article, the single word object is used in lieu of hollow object.

A positive or negative pressure is applied across the length of the object causing the sensitizing solution, for example, a solution containing Sn/++/, to flow uniformly through the interior surfaces of this object. Its interior surfaces having been sensitized, the object is rinsed with water by flowing fresh water past the sensitized surfaces. The object is then activated, for example, with Pd/++/, in a similar fashion. After activation, the object is rinsed again by flowing fresh water past the activated surface. The sensitizing and activation steps can be repeated two or more times if necessary.

The interior surfaces of the object are then plated using electroless plating solution of choice, for example, electroless solution containing nickel, cobalt, iron, copper, silver, gold, tin or other metal ions or mixture thereof. As above, a pressure differential is applied across the length of the object. Plating solution is thus caused to flow uniformly through the object, continuously replenishing the plating solution at the interior surfaces to be plated. The plating solution is forced through the object for a time sufficient to obtain the desired film thickness. The resulting film formed is a deposit of electroless metal or metal alloy whose composition depends...