Unisys Corporation

Other

Kenneth Walter Economy

Ronald Allen Norell

Richard Leigh Bumann

Gerald R Dunn

Thomas A Snodgrass

I/O columns are cast on the I/O pads of an electronic component via a process which uses a template that has a set of alignment holes, and a set of casting holes, and an additional set of pin holes that are interspersed with the casting holes. Initially, the template is placed in a fixture such that the casting holes align with the I/O pads of the electronic component. Next, the template is covered with a mask that exposes all of the casting holes but blocks all of the pin holes. Then the exposed casting holes in the template are filled with a solid metallic material. Next the mask is removed, and the metallic material in the casting holes is melted and re-solidified to thereby form the I/O columns on the I/O pads. Then the electronic component with its I/o columns is separated from the template by pushing on the component with pins that are passed through the pin holes in the template. Since the pin holes are interspersed with the casting holes, the electronic component is pushed away from the mask without bending the template. Consequently, the I/O columns do not bind in the casting holes; and thus they do not break as they pushed from the template.

Method of casting I/O columns on an electronic component with a high

A method of cutting input/output columns on an electronic component includes the steps of: providing a shear plate which has a thickness that is less than the length of the columns and which has respective holes for receiving all of the columns; inserting the columns into the holes until a portion of the columns extend past the shear plate; placing a blade, with a cutting edge, at an acute angle against the shear plate such that only the cutting edge of the blade touches the shear plate; and, sliding the cutting edge of the blade against shear plate and through the portion of the columns which extend past the shear plate, while keeping the blade at the acute angle. With this method, crater-like voids and burrs on the cut ends of the columns are eliminated.

Method of forming I/O columns with open ends that are free of

Solder balls are placed onto multiple I/O pads of an integrated circuit package by the steps of a) providing a template with a channel which has multiple openings on a surface of the template that match the pattern of the I/O pads; b) pouring a plurality of the solder balls onto the surface of the template; c) vibrating the template and thereby seating a respective solder ball in each of the template openings; d) turning the template over, after the vibrating step and while a vacuum is applied to the channel, to remove excess solder balls from the template; and e) removing the vacuum from the channel when the solder balls on the turned over template are aligned to the I/O pads of the integrated circuit package. Due to the vibrating step, the solder balls settle in the template openings in a position where vacuum leaks past the solder balls become minimized; and that stops the solder balls from dropping out of the template openings when the template is turned over. Also, since the steps a-d place the solder balls on all of the I/O pads in parallel, the time in which those steps are performed is many times smaller than the time in which a pick and place machine can put the solder balls on all of the I/O pads sequentially.

Vibrating template method of placing solder balls on the I/O pads of an

Multiple I/O pads are arranged in a pattern on a surface of an integrated circuit package, and an obstruction in the package prevents a planer solder flux mask from lying flat on the surface around the I/O pads. Such an obstruction can, for example, be a lid in the package which projects above the I/O pads, or it can be an encapsulant which covers a chip in the package and projects above the I/O pads. Despite the presence of the obstruction, solder flux is dispensed on the I/O pads of the integrated circuit package by the steps of --a) providing a pin block that has a base from which multiple pins project, and the ends of the pins match the pattern of the I/O pads; b) coating the ends of the pins with a solder flux; and, c) transferring a portion of the solder flux from the ends of the pins to the I/O pads by temporarily touching the coated ends of the pins against the I/O pads. During this transferring step, the coated ends of the pins are moved past the obstruction and touched against the I/O pads without touching the obstruction.

Pin block method of dispensing solder flux onto the I/O pads of an

A method of soldering component leads to I/O pads on a printed circuit board, without desoldering any other circuit components which were previously soldered to the board near the pads, includes the steps of: forming a mechanical assembly in which respective joints of the pads and the leads and respective solder mounds are mechanically held together; moving the assembly at a predetermined speed on a conveyor such that the joints, but not the previously soldered components, sequentially pass through a target area which is small relative to the total number of joints; and melting and then hardening the solder mounds, without desoldering the previously soldered components, by directing a focused stream of hot gas at the target area as the joints move therethrough on the conveyor.

Growing community of inventors

Escondido, CA, United States of America

Kenneth Walter Economy