:::
:::

R&D Focus

CINmat for Semiconductor Low Temperature Annealing

Video of CINmat.

The semiconductor industry has urgent demand for low temperature annealing process and equipment, as they are more effective in restraining diffusion for ion implantation than conventional rapid thermal annealing (RTA) or laser annealing techniques. In light of this, ITRI collaborated with National Chiao Tung University and the National Nano Device Laboratories in developing CINmat (Microwave Annealing Technology), aiming to solve the dopant diffusion issue of 12” wafers in the 5 nm semiconductor process and achieve dopant activation in the front end of line (FEOL).

Low temperature annealing is desired for the semiconductor industry.

Low temperature annealing is desired for the semiconductor industry.

The RTA or laser annealing methods use infrared or visible spectrum to heat silicon wafers. However, silicon atoms do not absorb those spectra directly and need higher temperature (> 600˚C) for dopant activation. On the other hand, silicon is a covalent bond material that can directly absorb electromagnetic wave energy. Therefore, the development of CINmat allows dopant activation at lower temperature (< 500˚C) and successfully avoids dopant diffusion, which is ideal for forming shallow junctions for the < 7 nm FEOL process.

CINmat employs spatial mode diversification and time-phase coupling techniques. Space mode type differential technology creates longitude, transverse, odd, and even modes, while coupled mode types of sequential microwaves avoid mode lock and maximize mode number. In addition, high dielectric constant material is used to enhance the absorption of electromagnetic waves. These techniques can provide 72 distinct modes, achieve the homogeneity required by semiconductor annealing process, and lower process cost by 85%.

The equipment of CINmat.

The equipment of CINmat.

CINmat is able to use 2.45 GHz microwave sources to finish sub-7 nm FEOL semiconductor annealing process. The data have been published in the 2016 IEEE IEDM Conference and 2017 Symposia on VLSI Technology and Circuits. The studies have shown that the 2.45 GHz microwave source has lower cost, higher efficiency, and longer lifetime than the commercial 5.8 GHz microwave annealing technique.

Featuring high performance, multi-wafer annealing, and lower cost, this technology can be applied in silicon semiconductor, optoelectronic, and chemical industries. Besides its outstanding performance in low temperature annealing, it will also help tremendously in energy saving and carbon reduction.