Last summer, it became known that TSMC intended to encourage industry participants to switch from using classic round silicon wafers to rectangular substrates measuring 510 x 515 mm. Now it is reported that after the first experiments, the company has decided to switch to square substrates measuring 310 x 310 mm.
Image Source: TSMC
The modern semiconductor industry produces advanced chips on round silicon wafers with a diameter of up to 300 mm. At the same time, the chip crystals themselves have a square or rectangular shape, which, taking into account the allowances at the edges necessary for the equipment to operate, forces the materials to be used in an uneconomical manner. The transition to rectangular or square substrates can solve this problem, but their implementation requires reworking the entire infrastructure and switching to new equipment for processing silicon substrates.
As Nikkei Asian Review notes, citing its own sources, TSMC has almost decided on the parameters of the next-generation silicon wafers, which will be square in shape and will be used in small quantities from 2027. Previous plans to use wafers measuring 510 x 515 mm had to be abandoned due to technological difficulties. The proposed standard with a square wafer of 310 x 310 mm will accommodate fewer chips, but will still increase efficiency compared to current round silicon wafers. TSMC is building a pilot production line in Taoyuan, where it hopes to begin processing square wafers of this size from 2027.
Taiwan-based chip testing and packaging services company ASE Technology originally planned to use 600 x 600 mm wafers, but is now ready to switch to 310 x 310 mm for unification purposes. Morgan Stanley estimates that the current 300 mm round silicon wafer can accommodate no more than 16 chips for Nvidia B200 accelerators, or no more than 12 chips for AMD Instinct MI355 accelerators, or no more than 25 Google TPU chips, and this is assuming no defects, which is never achievable in practice.
Initially, TSMC expected to adopt experience in working with rectangular wafers from display manufacturers, and even began to cooperate with Innolux, but then realized that partners from this industry did not have ready-made solutions for the implementation of square substrates in chip production, and therefore it would have to move forward mainly independently.
Not only TSMC and ASE are ready to migrate in this direction. Huawei Technology, which is under US sanctions, expects to gain the necessary experience with the assistance of Chinese companies BOE Technology and Tongfu Microelectronics.