Abstract: A process for reworking of PGA chip carriers where one or more I/O pins is unplated. The process includes electrolytically etching the I/O pins which removes any corrosion product from the unplated I/O pins and removes the top gold layer from the remaining I/O pins. The etchant includes a metal-providing compound selected from the group consisting of a silver salt, copper cyanide, silver cyanide, gold cyanide or mixtures thereof, at a concentration in the range from about 2.7 to about 4.1 g/l as metal; potassium or sodium carbonate at a concentration in the range from about 10 to about 100 g/l; and potassium or sodium cyanide at a concentration in the range from about 29 to about 35 g/l.

Abstract: A method of expanding a sintered alumina substrate which includes the step, after conventional sintering, of heating the sintered alumina substrate to a temperature of about 1340 to 1380.degree. C. and holding at the temperature for a predetermined time but no less than 15 minutes, the heating step causing the sintered alumina substrate to expand.

Abstract: A screening apparatus including a table for holding an article; and a dual reservoir dispensing assembly. The dual reservoir assembly includes first and second reservoirs for holding first and second materials to be dispensed; first and second nozzles in communication with first and second reservoirs, respectively, for dispensing first and second materials; tilting apparatus for tilting the nozzles in a first direction so that the first nozzle is tilted into position for dispensing the first material and for tilting the nozzles in a second direction so that the first nozzle is tilted out of position and the second nozzle is tilted into position for dispensing the second material; and apparatus for moving the dual reservoir dispensing assembly with respect to the table wherein, in operation, the first nozzle is tilted into position during a first movement across the article and the second nozzle is titled into position during a second movement across the article.

Abstract: A re-work method for removing extraneous plated metal layer areas from the surface of a ceramic substrate containing refractory metal areas wherein the substrate is heated at a temperature for a time sufficient to strengthen the bond between the plated metal layer and the refractory metal areas while simultaneously reducing the strength of the bond between the extraneous plated metal layer overlying the ceramic and the ceramic, immersing the substrate in a liquid, and applying localized ultrasonic energy in close proximity to the extraneous metal areas to be removed.