Test board for characterizing dendrite growth in immersion-cooling systems

A method for characterizing dendrite formation in immersion cooling systems with a test board assembly, the method comprising:

• immersing at least part of the test board assembly in an immersion cooling fluid, the test board assembly comprising:
• a first printed circuit board (PCB) having first contacts for a ball grid array (BGA);
• a second PCB having second contacts for the BGA;
• the BGA disposed between the first PCB and the second PCB and arranged to electronically couple the first contacts on the first PCB to the second contacts on the second PCB, wherein the BGA is at least partly immersed in immersion coolant liquid;
• and
• at least one heating element disposed on one or both of the first PCB and the second PCB to generate heat that couples to at least the BGA;
• generating heat with the at least one heating element to emulate heat generated by a semiconductor die;
• applying, for a period of time T, a voltage or a current to a contact of the first contacts or of the second contacts that is electrically coupled to a solder ball, a pillar, or a post of the BGA;
• and
• evaluating dendrite formation on the solder ball, the pillar, or the post as a result of applying the voltage or the current for the period of time T.