Removal of Defective I/O Pins
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
In the thermal conduction module (TCM) substrates used in semiconductor manufacturing, there are numerous input/output (I/O) pins brazed to the multilayer ceramic (MLC) substrate. Conventional methods of removing defective pins for repair purposes utilize heat and mechanical pulling which often lead to ceramic pullout damage. The invention proposes the use of a chemical solution to selectively dissolve the pin(s) to be removed. The connection between MLC substrates and the second level of packaging, such as printed circuit boards, is provided by an array of up to 1800 I/O pins. These are typically made of copper or a commercial iron-nickel-cobalt alloy, and plated with nickel or palladium and gold.