A second-level thermal interface material (TIM2) that is to couple to a system-level thermal solution is applied to an integrated circuit (IC) assembly comprising an IC die and an assembly substrate prior to the assembly substrate being joined to a host component at the system-level. Challenges associated with TIM2 application may therefore be addressed at a first level of IC die integration, simplifying subsequent assembly and better controlling thermal coupling to a subsequently applied thermal solution. Where a first-level IC assembly includes a stiffener, the TIM may be affixed to the stiffener through an adhesive bond or a fusion bond. After the IC assembly including the TIM is soldered to the host board, a thermal solution may be placed in contact with the TIM. With early application of a solder TIM, a solder TIM may be reflowed upon the IC die multiple times.