Papers by Author: H. Shirakawa

Abstract: In semiconductor device manufacturing, single wafer processors are widely used in not only BEOL process but also in FEOL process for 2X devices to improve the cleaning efficiency and get the higher productivity. Because the scaled down devices require the minimum substrate loss in the cleaning steps, the physical force by a dual fluid spray is still the main position to improve the cleaning efficiency at the moment comparing with chemical effects as the dissolution of contaminants and/or the lift off of particles. Sato, et al., reported that the relationship between particle removal and droplet characteristics linked to the droplet energy density E_d as following equation [. The kinetic energy E_k of droplet is calculated from droplet diameter d and velocity v, as shown in Equation 1.

Abstract: Since silicon will ultimately face physical limitations, germanium and III-V materials, such as Ga, GaAs, InGaAs, are being extensively investigated for their high electron and hole mobility advantages. Prior to implementing germanium or III-V materials, it is believed that SiGe with high Ge concentration will be applied for channel materials in pMOS devices with high-k and metal gates in order to simultaneously adjust the work function and to increase the hole mobility. However, introduction of new channel materials leads to new challenges and substantial changes in the FEOL process flow.

Abstract: A novel advanced spray technology, in which droplet size and velocity are accurately and tightly controlled, has been developed to realize the damage-free cleaning for next generation device manufacturing. The influence of droplet characteristics on pattern collapse/damage was quantitatively investigated using this technology. It was shown that the amount of damage was correlated to the droplet energy density on the wafer. The mechanism of pattern damage generated by the conventional dual fluid spray was revealed by the damage threshold curve, which was obtained from the theoretical consideration. Finally higher particle removal efficiency without any pattern damage was achieved by controlling the distribution of effective droplets for cleaning.

Abstract: In the very near future 32(28)-nm node device technology innovations will enter high volume manufacturing. New materials and structures, e.g. high-k (HK), high-k cap (HK cap), metal gate (MG) and SiGe channel, are being highly considered. Requirements for wet processing are varied according to metal-first or metal-last integration schemes. [1, 2, 3] One of the biggest challenges in wet processing for implementing new materials and structures is to achieve both high selectivity and low substrate loss. At some wet cleaning or etching processes, standard chemicals, e.g. APM, HF and O3, can be accommodated by optimizing the chemical condition. However, photoresist (PR) strip processes require the development of new chemicals or techniques, since SPM does not have sufficient compatibility against presently reported materials. This study focused on the PR strip technique via the dissolution and swelling effects in solvent, and an applicable process technique and its effectiveness for 32(28)-nm and beyond device fabrication is reported.