Philip Garrou

ST Micro announces more CMOS Image Sensor Packaging Capacity with TSV
March 5, 2008

ST enters CIS camera market place with 3D TSV technology

ST's claims its latest 2M pixel mobile-phone camera module VD6725 is the worlds smallest single-chip camera sensor for mobile applications.

The VD6725 is available in ST's TSV (Through Silicon Via) wafer-level package, which enables the production of reflowable camera modules. These are soldered directly on the phone motherboard, which saves cost, space and time compared with the process of fixing traditional camera modules in the board socket. ST is one of the very few companies that have reflowable camera modules in production. Volume production is scheduled for the end of June. Unit pricing is in the $2 range, depending on the production period and quantities.

More pre conference info from the 3D IC Integration sessions at the March 2008 IMAPS Device Packaging Conference

The upcoming IMAPS Device Packaging Conference will have several papers from Chester Balut, Pedro Jorge and the DuPont Electronics team dealing with using dry film photoresist for 3D IC integration and copper pillar metallization schemes.

My recollection is that dry film was an integral part of the FCT (Flip Chip Technologies) licensed process technology for redistribution and solder paste bumping developed by Pete Elenius and his group 10+ years ago. Point is that the material has proven its stripes commercially and is being used by nearly all the bump / WLP processes in Taiwan and Korea (since all of them licensed the old FCT process). Their copper pillar technology is being developed with Alan Huffman at Research Triangle Institute. They examined 75, 100 and 120 um dry film and were able to plate up very respectable copper studs. Huffman says "...the key to useing such dry film materials is that the processing time is very short when compared to comparable thickness single spin photoresist (i.e. bake time exposure time etc.)...thats the key ! "

This group has also studied the use of dry film photoresist to “tent” TSV while other processes are underway. By controlling polymer flow during lamination with temperature, pressure and speed, dry film is capable of applying a uniform layer of photoresist on wafers with TSV. This ends up being a highly useful processing step which allows other fabrication to be done with open blind vias without getting process chemicals into the holes. I’m sure a lot of you out them can conceive of unique processes that this would allow in a 3D process sequence, I know I can.

For more information on using dry film photoresist for 3D processing see the full papers at the IMAPS conference. For all the latest on 3D integration and other advanced technologies stay linked to Perspectives From the Leading Edge……..

Posted by Philip Garrou on March 5, 2008 | Comments (0)