Pressure Distribution Control on Surface Conformable Polishing in Chemical Mechanical Planarization

Abstract

An original polishing mechanism with a triple layer pad was developed as a surface conformable polishing mechanism in CMP (Chemical Mechanical Planarization). According to the polishing mechanism, removal profile can be controlled by base plate curvature through an assist pad made of elastic material. A pad system supported by an envelope plane composed of five wafers contributes to make a wafer level paralleled to a pad level relatively during polishing. As the result, a static pressure distribution can be transferred precisely to a dynamic polishing profile regardless of strong shearing force by polishing. In order to verify the polishing removal controllability, an original pressure distribution analysis was developed by an actual pressure distribution measurement around an entire pad surface. The analyzed pressure distribution profile was in good agreement with the actual polishing profile. From the result that the static pressure profile can be transferred to the polishing profile precisely, it was verified that the polishing mechanism is reasonable for surface conformable polishing system in CMP.

Profile control processes based on contact types in silicon wafer DSP manufacturing management

“…Compared to the method of changing the base platen curvature, the method of changing the pad profile is more flexible. 30 However, the effect of the pad profile is regional and limited. Meanwhile, the convex pad dressing resulted in the shorter life of the polishing pad.…”

“…The finite element method proved to be an effective tool in the simulations of CMP. 30 To verify the pressure distribution between the silicon wafer and the polishing pad, a finite element model was established in COMSOL Multiphysics. The model was a three-layer structure consisting of a steel platen, a polyurethane pad and a silicon wafer.…”

Research on R-Plane Sapphire Substrate CMP Removal Rate Based on a New-Type Alkaline Slurry

“…[10][11][12] Chemical mechanical polishing (CMP) is almost only accepted global planarization technology for sapphire because of its simple operation, high processing efficiency, and low surface roughness level. [13][14][15] The hexagonal-scalenohedral crystal structure of sapphire results in material anisotropy along different crystal orientation. 16 So for sapphire wafer CMP with different crystal orientation, there are still many theoretical and technical problems, especially material removal mechanism which is still poorly studied due to the complex material characteristic.…”

Computational analysis and chemical mechanical polishing for manufacturing of optical components

“…Effects of pressure on the non-uniformity and surface roughness have been investigated by many researchers [22,26,31,38,39,[51][52][53][54][55][56][57][58][59]. In traditional CMP, when pressure increases, MRR increases linearly, non-uniformity is slightly reduced [26,31], and the surface roughness increases [54].…”

“…Fujita and Wantanabe [59] have proposed that the wafer should be placed stable on a plate with the polishing face is up instead of facing down (Figure 2.3). The plate keeps the wafer as flat as it is.…”