Browse Prior Art Database

REMOVABLE BUS-BAR FOR ELECTROPLATING OPERATIONS

IP.com Disclosure Number: IPCOM000007758D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2002-Apr-19
Document File: 2 page(s) / 88K

Publishing Venue

Motorola

Related People

Thomas G. Wiegele: AUTHOR

Abstract

When electroplating printed circuit boards, it is often desired to deposit metal only at particular regions rather than over the entire area of the board. This typically involves multiple deposition and patterned etching steps which can be costly and time- consuming. In addition, valuable board space is often consumed by running a bus-bar to the board edge, where electrical contact is established via an electroplating rack. The irregular geometries associated with typical bus-bars can also lead to non- uniform electrodeposits in the regions ofinterest.

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MmROLA Technical Developments

8

REMOVABLE BUS-BAR FOR ELECTROPLATING OPERATIONS

by Thomas G. Wiegele

  When electroplating printed circuit boards, it is often desired to deposit metal only at particular regions rather than over the entire area of the board. This typically involves multiple deposition and patterned etching steps which can be costly and time- consuming. In addition, valuable board space is often consumed by running a bus-bar to the board edge, where electrical contact is established via an electroplating rack. The irregular geometries associated with typical bus-bars can also lead to non- uniform electrodeposits in the regions ofinterest.

  The solution to these problems lies in the use of a conductive foil which can be placed over the sub- strate to be used as a removable bus-bar. This con- ductive foil is forced into mechanical and electrical contact with the substrate through the use of a dry- film photoresist laminator, where a dry-film photoresist is used as the plating mask. By covering this removable bus-bar with photoresist, plating on the bus-bar is prevented. Openings must be created in the bus-bar in those regions in which electro- plating is desired. Aher the lamination process, stand- ard photolithographic and electrodeposition proce- dures can be employed to define the metallization pattern. Because the areas to be plated are electri-

cally connected in parallel and over a large area, the uniformity ofthe electrodeposit is very high.

  The procedure, illustrated in the figure below, requires the creation of a bus-bar from...