The ST10-LC909 polyimide product is a claimed price competitive replacement for Thermount and Copper Invar Copper, and is used to control the thermal expansion of PCBs.

According to the company, the product closely matches ceramic and flip-chip type low coefficient of thermal expansion (CTE) components, and that a multi-layer board manufactured using polyimide and Copper Invar Copper or Thermount materials can be duplicated using layers of standard polyimide and ST10-LC909 embedded into the PCB. The process will reportedly match the CTE of an existing design, targeting a range from 9ppm/°C to 12ppm/°C, with a low Z-axis expansion.

stablcor.com