Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

BGA Rework Using Laser Selective Reflow

Dave J


BGA Rework Using Laser Selective Reflow | 3 January, 2005

One of the difficulties with BGA rework is excessive heating of the internal package (die) temperature. We have several "SRT" hot air rework systems which work well, but with Pb-Free components the challenge becomes even greater. The question I have - is there a better technology than hot air to handle this rework?

Specifically, I am inquiring of Selective Soldering (BGA rework) utilizing lasers. There are several companies, one of them being VI Technologies, selling equipment that allegedly develops no "hot spots" in a component. How does the laser access solder balls under the package? In theory, having a tool which applies heat at "point of use" and keeps the internal die as well as close adjacent components at relatively low temperatures would be utopia.

Is there anyone out there that has real life experience with BGA rework using laser reflow equipment?


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BGA Rework Using Laser Selective Reflow | 4 January, 2005

No mystery there... The balls are reflowed by conduction of heat from the package itself and the backside preheater just as in any other rework machine. The laser is just another method of precisely heating the entire package. The advantage is overall watt density and the fact that that the rasterized heat pattern can be closely matched to the actual size and shape of the component. Laser systems should incorporate an optical pyrometer which can monitor power while corresponding that to an actual heat profile in real time or else thermal runaway can easily occur. Laser is probably more efficient that hot air, but transfering heat to a package by scanning a defocused laser with galvonometer over the surface of the package is much more expensive than the alternatives. Another technology we evaluated extensively which gives impressive theramal results is focused IR. Check out:

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James Khor


BGA Rework Using Laser Selective Reflow | 6 January, 2005

You can using Ersa IR550A Rework System. The unit was NOT using any hot air process. IR550A Rework System is worldwide the only system with a genuine closed loop control system. Which employs the current temperature at the component in order to regulate the process. The patented aperture control makes component-specific nozzles and inserts unnecessary. In addition the system offers the professional user 1,600 W of the heating power and repeatable, top-quality lead-free soldering results. The included ERSA IRSoft allows the lead-free rework process to be fully documented for the first time and represents a milestone in quality assurance for rework processes. You can go to the website :

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