https://devzone.nordicsemi.com/f/nordic-q-a/4163/about-wlcsp-packageDears : we will use WLCSP package. And, we want to know more information about it as below: 1.Marking side is strong enough right? 2. We only need to take care of side edges and ball side. We use black glue pasted on side edges and ball side, isen-USTelligent Community 13Tue, 21 Oct 2014 12:13:34 GMThttps://devzone.nordicsemi.com/thread/14908?ContentTypeID=1Tue, 21 Oct 2014 12:13:34 GMT137ad170-7792-4731-bb38-c0d22fbe4515:487a3ff1-9829-4d10-8a6f-06fef6d86cc6Asbj&#248;rn<p>The top side where the chip markings are written is covered with coating. You will only need to cover the side and ball side (if needed). Black glues that&#39;s non-conductive and not penetrable for IR light will be fine. Also, for a lot of applications, the housing itself will cover and protect the chip, but glue would be recommended.</p><div style="clear:both;"></div>