Expansion Coefficient
Thermal expansion parameter defines the growth of a substrate per degree of temperature change. The interposer cte identifies the rate at which the intermediate substrate in a multi chip package expands or contracts during thermal cycles. This value determines the mechanical compatibility between the silicon die and the printed circuit board.
Mechanical Stress
Differences in expansion rates between layers cause warping or solder joint failure. Because silicon has a very low coefficient of expansion, an interposer cte that closely matches silicon reduces the strain on the micro bumps.
Material Composition
Substrate selection determines the thermal performance of the assembly. Silicon interposers provide a perfect match but add high cost to the assembly. Organic or glass substrates offer alternative values that engineers must balance against the requirements for high speed signaling and heat dissipation.
Metrological Alignment
Dilatometry measurements verify the expansion properties across the operating temperature range of the device. Thermomechanical analysis provides a detailed profile of how the interposer cte varies, ensuring that the package survives the reflow oven and subsequent field use. Testing at multiple points along the assembly chain confirms that the material properties remain stable after exposure to chemical etchants or bonding adhesives.
