According to a report from Digitimes, AMD’s chip shortages are primarily due to ABF substrate shortages rather than limited foundry capacity at TSMC. Recently, rumors had started popping up, claiming that AMD may divert some of its APU and GPU production to Samsung’s advanced foundries to ease the shortages.
DT believes that AMD is unlikely to transfer any of its future 5nm or 3nm from TSMC to Samsung, but I’d take this particular claim with a grain of salt as the outlet has repeatedly been wrong with similar reports. There appears to be a strong bias towards TSMC, not surprising considering that it’s a Taiwanese media outlet.
ABF, otherwise known as “Ajinomoto Build-up Film” is a resin substrate that acts as an insulator in all modern ICs. The ABF is a highly durable and rigid film that resists expansion and contraction with changes in temperature, making it ideal for use as a substrate between the nanometer-scale and millimeter-scale components of a processor or IC.
The AFB substrate consists of multiple layers of microcircuits, known as a “build-up substrate” which allows the formation of these miniature components as its surface is receptive to laser processing and direct copper plating. Most modern chipmakers use ABF to design the smaller components of their CPUs and GPUs.
According to sources close to ABF, the supply of ABF substrates is expected to become one of the major factors behind CPU and GPU shortages in 2021. Fabless chipmakers like NVIDIA and AMD are expected to be one of the main companies affected by this issue.