Hybrid Effect Study of Pad-Conditioning/Slurry-Supply by High-Pressure-Micro-Jet (HPMJ) Method during CMP Process

Abstract

Surface clogging of polishing pad is inevitable during CMP (Chemical Mechanical Polishing) process of semiconductor wafers. In this paper, a novel slurry-feeding system utilizing HPMJ (High Pressure Micro Jet) apparatus was presented as in situ conditioning for CMP process. Clogging of pad surface can be greatly removed; the surface damage of polishing pad can also be extremely reduced by this new method. The experimental results exhibited that the material remove rate (MRR) of HPMJ method was almost constant value 100 μm h−1. However, the MRR value of conventional slurry-dripping method was about 50 μm h−1. On the other hand, surface roughness Ra changed both in hybrid HPMJ method and conventional slurry-dripping method after long-time continuous CMP process, the average Ra of hybrid HPMJ method was about 30% smaller than that of conventional slurry-dripping method, indicating that better surface quality could be obtained by HPMJ method polishing. It was demonstrated that HPMJ method showed higher MRR and lower surface roughness Ra for polishing process. HPMJ hybrid system mentioned in this study can also be applied to the polishing process of hard-to-process wide bandgap semiconductor substrate materials, such as SiC or GaN.

Tribological glazing evolution of fixed abrasive pad under different polishing solution conditions

“…The above-mentioned conclusions have indicated that the surface-glazed phenomenon of polishing pad is existed in CMP process, which has important effect on the CMP performance. Thus, the diamond conditioners (Zhou et al, 2008;Wang et al, 2020aWang et al, , 2020b, high pressure micro jet (Tsai and Yang, 2012;Kim et al, 2005) and other technologies (Shin et al, 2016) were proposed for solving this problem of polishing pad. The experimental results have showed that these technologies can remove the glazed layer on the pad surface, which improves the material removal ability of the polishing pad.…”

“…A research conclusion was proposed that the self-dressing performance of the pad had limited effect on its surface-glazed phenomena which was also occurred after a longer using time. Wang et al (2020aWang et al ( , 2020b researched the surface characteristics of FAP with selfconditioning ability using Si 3 N 4 ceramic sheet polishing experiment under different solution pH values condition. The experimental results showed that a certain degree of wear and glazed phenomenon on the FAP surface was also existed in the CMP process.…”

“…Lee et al (2017) investigated the effect of self-dressing property of fixed abrasive pad with sapphire substrate on its glazed phenomenon. A research conclusion was proposed that the self-dressing performance of the pad had limited effect on its surface-glazed phenomena which was also occurred after a longer using time Wang et al (2020a, 2020b…”