A bottom side interposer provides a structurally balanced chip carrier module to reduce thermal warp and increase package robustness. The bottom side interposer is attached to the bottom of a chip carrier which carries semiconductor chips on the top side of the chip carrier. The top side of the chip carrier typically includes a top side interposer between the semiconductor chips and the chip carrier. The bottom side interposer has a coefficient of thermal expansion (CTE) that is similar to the chips and top side interposer, or tailored to have a CTE intermediate to the chips and the chip carrier. Pads on the bottom side interposer may be plated or fitted with solder balls to complete the module so the module can be connected to a printed circuit board.