And here we’ve been complaining about Flat Pack No-Lead chips when this guy is prototyping with Ball Grid Array in a Wafer-Level Chip Scale Package (WLCSP). Haven’t heard that acronym before?

Keeping the wafers flat before and after bonding to the carrier wafer is also very difficult. “If you have two flat wafers, they will not be flat after bonding because the process induces distortion,” ...