Wafer Bumping Flux
Solder bumps on wafers may be produced by a variety of processes. For bumps with a pitch greater than 100microns, solder paste is often used to form the bump. Solder bumping of the top surface of BGA and PGA substrates for solder-on-pad (SOP) usually uses a very fine solder paste rather than plating. Formation of the much larger (0.3-0.6mm pitch) solder bumps on waferlevel CSPs is by a ball-drop process.
Solder Bumping Blog Posts
The ball-attach process can be considered a trivial step when creating an FCBGA or similar package, but the final soldering step can be rather complex. There are several variables that impact the final ball-attachment from the number of assembly processes needed before. These processes can be…
While in South East Asia last summer, Indium's technical team and I had a chance to discuss flip-chip dipping processes with a major equipment vendor. One of the topics was device (bumped package or die) "pick-up" out of a flip-chip flux dipping tray, and how different factors affect…
Wafer bumping processes have evolved in the last 10 years. The semiconductor assembly industry has gone from bumping processes using solder paste printing (with all its concerns of voiding, coplanarity, stencil-life, and spatter) to plated solder bumps, and now to plated copper pillars with microbumps…
Andy C. Mackie, PhD, MSc
Senior Product Manager, Semiconductor Assembly Materials
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