nrf51822 Beacon HW: Now with black goop!

[Jerod]

Just ordered another pair of beacon hardware and noted the nrf chip is now coated in black goop.

Curious as to what this is for, and the reasoning its been added to the hardware. It actually covers pin 5 -- so I'd like to understand if its safe to scratch off.

i.e. Is this glue to keep chip in place, or thermal related, and how this might relate to chip temp readings, or how this translates to recommendations for our own hardware design

Any info would be great!

(updated) with photo (forgive the exposure; 2 on the right just arrived this week):

[Petter Myhre]

Section 7.1 in the nRF51822 Product Specification states: "The WLCSP package variant is sensitive to visible and near infrared light which means a final product design must shield the chip properly. The marking side is covered with a light absorbing film, while the side edges of the chip and the ball side must be protected by coating or other means."

This "black goop" is this "coating or other means".

It is not supposed to cover the pins. If you need pin 5, you can try to scratch it off pin 5, but I can't say it is safe. Please be careful.