I am building a rugged digital video camera product that essentially is just a sandwitch of 3 parts:
#1: front piece is machined aluminum with C-mount thread #2: middle piece is 1/16" printed circuit board #3: back piece is machined aluminum
These 3 pieces are bolted together with M3 bolts at the four corners (with clearance holes in #1 and #2 and threaded holes in #3).
On the middle of #2 (the PCB) is an image sensor in an iLCC package. Essentially the iLCC package is just like a QFN except package with a quartz window over the image sensor chip inside.
I need the distance between the front surface of #1 to be exactly the correct distance to the image sensor. The specifications for the position of the image sensor surface in the package is given in the image sensor specification, so I can calculate the appropriate thickness of the front of the case #1 to the PCB #2.
However, the melted solder under the iLCC contacts will raise the image sensor up slightly. Assuming I have a 0.005" thick stencil (which I do), how thick is the bottom of the chip likely to be once the solderpaste is melted and hardens in the reflow oven?
Will it be 0.005" or something less or more? The openings in the soldermask are just a hair larger than the openings in the solderpaste stencil (about 0.001" ~ 0.002" smaller).
I'm guessing 0.004". But that's a guess.
Does anyone know?
Thanks
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