Aspects of the invention include a non-destructive bond line thickness measurement of thermal interface material on silicon packages. A non-limiting example computer-implemented method includes receiving a chip mounted on a laminate and depositing a high-density material on the chip. The computer-implemented method deposits a thermal interface material on the chip and lids the chip, and the laminate with a lid. The computer-implemented method X-rays the lid, the chip, and the laminate to produce an X-ray and measures, using a processor, from the X-ray a bond line thickness of the TIM as a distance from a bottom of the lid to a top surface of the high-density material.