Compaq Computer Corporation, Inc.

Ronald D Denton

Andrew J Mawer

Timothy M McGuiggan

George H Bumgardner

A method and apparatus are available for manufacturing a printed circuit board assembly by reworking a ball grid array component on a populated circuit board. The component is first aligned over the landing area on the board. Then hot gas is injected between the component and the board. This gas is hot enough to reflow the solder balls on the component. Then the component is connected to the landing area of the board. The component is held away from the board during the reflow step and is dropped onto the landing area after the solder balls reflow. A special nozzle and nozzle insert are used to hold the component away from the PCB by means of a vacuum suction.

Method and apparatus for assembling ball grid array components on

A technique for minimizing heat-induced chipside solder joint fractures involving BGA (Ball Grid Array) components mounted on a multilayer printed circuit board when the board is passed through a wavesolder oven. The technique involves shielding the chipside solder joints from the effects of conductive heating by covering the through vias positioned underneath the BGA components with an insulating material. The insulating materials include silk screen material, solder mask and KAPTON tape. During wavesolder, the insulating material blocks conductive heat flow from the exposed board face through the vias and into the BGA component landing areas. With the wavesolder heat flow blocked, the BGA landing areas and BGA components experience much less heat deformation, and a much lower solder joint defect rate is achieved. Selection of silk screen, solder mask or KAPTON tape is based on a balance of solder process conditions and effective insulation capability, with the lowest cost, most effective solution preferred.

Growing community of inventors

Spring, TX, United States of America

Ronald D Denton