MCM & Custom BGA's :: Custom Interconnect Limited

COB - Chip on board

Chip on Board - COB semiconductor assembly is the technology that CIL really excels at. Bare semiconductor die are mounted on a printed circuit board or substrate using conductive or non-conductive epoxies. These bonded die are then 100% encapsulated (glob top), part encapsulated or left completely exposed. With CIL's eight SMT lines covering prototype, small, medium and volume PCBA using 01005 / 0201 components, this highly compliments CIL's semiconductor packaging and die / wire bond using COB technology. Assemblies with single or multiple dies and wire bonds of 1 off to 1000 off / assembly are all part of CIL's process portfolio.


In most instances, the base substrate is FR4 laminate and Aluminium wedge bonding is the preferred wire bonding technique, but all other substrates and wire bond techniques can be used.

CIL can also attach a die face-down onto a PCB using flip-chip technology using solder balls pre-applied at a wafer level or using Thru Silicon Vias (TSV) process techniques. The die is then encapsulated using a glob top or Dam / Fill encapsulation process. Another process area that CIL excels at is the partial encapsulation / glob top of COB devices whereby active areas of the die have to remain open, but all wire bonding has to be encapsulated. With modern complex die designs, this means CIL has had to evolve wet epoxy  processes controlled to <25um. In very small quantities, CIL operators perform this manually, but for medium to volume quantities CIL has this fully automated and can control dam & fill glob top material to within 25um, thus encapsulating the bonds, but not contaminating the active die area. CIL has 4 Automatic ASYMTEK Glob top dispensers performing this operation seen below

Irrespective of product size or weight issues, CIL has probably encountered it. We are currently working with the very latest Chip Scale and Wafer Scale Packages and looking at the requirements for placing, soldering and cleaning of these devices alongside that of standard SMT Components. Feel free to get in touch with our Advanced Technology Team and have a conversation regarding your particular requirements.

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