EPC901 Datasheet, PDF (32/37 Pages) Espros Photonics corp – CCD line sensor 1024x1 pixel

13.3.2. PCB design and SMD manufacturing process considerations
Since the epc901 chip comes in a very small 32 pin chip scale package, the PCB layout should be made with special care. Since the
silicon chip is small and light weight compared to the solder balls, it is highly recommended that all tracks to the chip should come straight
from the side. A consequent symmetrical design is therefore highly recommended to achieve high production yield.
The pads and the tracks should also have exactly the same width and shall be covered by a solder resist mask in order to avoid drain of
the solder tin alloy to the track.
8.000
track
ø0.3
(straight only for 0.25mm!)
landing pad
solder resist mask opening
solder resist mask
max. 0.15
ø0.4
chip perimeter
all measures in mm
Figure 17: Recommended PCB layout
Underfill of the components reduces stress to the solder pads caused by e.g. temperature cycling or mechanical bending.The thermal and
mechanical fatigue will be reduced and the longterm reliability will be increased. Underfill and underfill selection is application specific. It
shall follow JEDEC-STD JEP150: Stress-Test-Driven Qualification of and Failure Mechanisms Associated with Assembled Solid State
Surface- Mount Components.
Please also refer to the application note AN04 - Assembly of Wafer Level Chip Scale (WL-CSP) Packages - which can be downloaded
from the ESPROS website at www.espros.com/application-notes. Obeying the recommendations in the applications AN04, a high manu-
facturing yield can be achieved.
© 2016 ESPROS Photonics Corporation
Characteristics subject to change without notice
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