Ask the Experts
November 12, 2007 - Updated
November 12, 2007 - Originally Posted

Rework Metal BGA's

I am having problems reworking metal BGA's with our IR rework station. Is it possible to consistently rework metal BGA's with IR, and is there a preferred methodology to achieve this?

J. U.

Expert Panel Responses

The problem you are facing is due to the IR energy bouncing off the reflective surface of the metal topped BGA. Your easiest solution is to switch to a convection rework system that uses hot air from the bottom of the board and the top of the component to melt the solder. A convection rework machine will provide even heating regardless of the reflectivity of the surface being reworked. In addition, the hot air provides a gentler ramp up to reflow, better emulating the oven reflow process.

Edward Zamborsky
Regional Sales Manager
OK International Inc.
Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

We are possible the manufacturer of your rework system - PDR. We use a 'black conductive tape' which does two things . . . it better conducts and distributes the heat . . . and secondly, it corrects the emmissivity of the component surface . . . so that you can get an accurate temperature reading. Metal components should be no problem. Any further problems contact me.

Roger Gibbs
Managing Director
Twenty years ago Mr. Gibbs, Managing Director of PDR, produced the first rework system based on Focused Infra-Red light energy. PDR now has a 3,500-strong global installation list with top OEMs and EMS providers.

The issue with any BGA is mass related, and profile to the circuit. Getting enough energy into the device is the challenge and managing the energy transfer rates at the edges of the Part to the centre of the part are also difficult. One alternative methodology being used is Vapor Phase. The energy management issues are overcome and the parts can be successfully removed and replaced in an Oxygen free environment.

Allen W. Duck
ATEK llc
Allen Duck is a 20-year Electronics Industry veteran with Global experience in multiple fields of technology and management. He started A-Tek in 2006 to provide a sales and service channel for international equipment companies wishing to offer value based solutions to USA companies.
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