Only three PCB makers currently meet the requirements for 3.2T optical module boards, according to an industry source cited by DIGITIMES: Zhen Ding Tech (4958 TT), Unimicron (3037 TT) and Shennan Circuits (002916 CH). The modules are expected to begin shipping in 2028. Their boards require line widths and spacing of 10 to 15 microns, which could push production from mSAP to the more complex SAP process. Suppliers also need FC-BGA substrate capacity. More suppliers, including Compeq (2313 TT), can handle mSAP, which supports line widths and spacing of 12 to 25 microns. Boards for 1.6T modules already require mSAP and M8 laminates, while M9 is planned for 3.2T boards. The ramp-up is expected to overlap with the IC substrate shortage. Module makers that don’t reserve capacity early could end up competing with AI and HPC chipmakers for production slots.