Using its independently developed low-leakage process technology, UMC has manufactured the foundry industry’s first fully functional 28-nm SRAM chips, according to the company. UMC employed advanced double-patterning immersion lithography and strained silicon technology to produce the chips, which feature six-transistor SRAM cell sizes of approximately 0.122 µm2.
UMC incorporates a dual approach for its 28-nm technology in order to address different market applications. The foundry uses conventional silicon gate/silicon-oxy-nitride gate oxide technology for its low-leakage process, which is ideal for portable applications such as mobile phone ICs. The second option will use a high-k/metal gate stack for speed-intensive products such as graphic, application processor, and high-speed communication ICs. The 28-nm process provides almost twice the density of the 40-nm technology, which is currently being produced at UMC’s 300-mm fabs. The company will also provide foundry services for customized 32-nm technologies based on its 28-nm process platform.
“UMC’s continued R&D commitment has helped us maintain our leadership position in nanometer technology over the years,” said S.C. Chien, vice president of advanced technology development at UMC. “We are excited about this latest achievement for 28 nm, as it provides a solid starting point for further development of this technology node towards mainstream availability down the road. Improvements in areas such as minimum supply-voltage, modeling of strain effects, and natural yield will be our focus going forward.”