Effect of Conditioner Type and Downforce, and Pad Surface Micro-Texture on SiO2 Chemical Mechanical Planarization Performance

Abstract

Based on a previous work where we investigated the effect of conditioner type and downforce on the evolution of pad surface micro-texture during break-in, we have chosen certain break-in conditions to carry out subsequent blanket SiO2 wafer polishing studies. Two different conditioner discs were used in conjunction with up to two different conditioning downforces. For each disc-downforce combination, mini-marathons were run using SiO2 wafers. Prior to polishing, each pad was broken-in for 30 min with one of the conditioner-downforce combinations. The goal of this study was to polish wafers after this break-in to see how the polishing process behaved immediately after break-in. One of the discs used in this study produced similar micro-texture results at both downforces, which echoed the results seen in the mini-marathon. When comparing the different polishing results obtained from breaking-in the pad with the different discs used in this study, the coefficient of friction (COF) and SiO2 removal rate (RR) were uncorrelated in all cases. However, the use of different discs resulted in different COF and RR trends. The uncorrelated COF and RR, as well as the differing trends, were explained by pad micro-texture results (i.e. the differing amount of fractured, poorly supported pad asperity summits).

Tribological, Thermal, Kinetic, and Pad Micro-Textural Studies Using Polyphenylene Sulfide Retaining Rings in Interlayer Dielectric Chemical Mechanical Planarization

“…For better visualization, high and low areas of all images have been accentuated through a transformation that involves taking the inverse hyperbolic sine of the height data. 16,17,[37][38][39][40][41][42] The scale bar is also kept the same for all images to allow for visual comparisons. Red indicates the highest parts of the pad surface and is, therefore, representative of asperities.…”

“…Red indicates the highest parts of the pad surface and is, therefore, representative of asperities. 16,17,[37][38][39][40][41][42] Color changes from red to yellow, and then to green, indicate decreasing heights, with a certain shade of green representing the mean surface height, indicative of interpore land areas. 16,17,[37][38][39][40][41][42] Color shifts to light blue, and then to dark blue, represent gradually decreasing heights all the way to the bottom of the pores.…”

“…A more detailed description of the methods used by our group for pad topography analysis can be found elsewhere. 16,17,[37][38][39][40][41][42]…”

Characterization and dressing effect of CMP diamond disc conditioner with ordered abrasive distribution

“…Kwon et al [24] found that the higher the density of grains on the dressing tool, the smaller the surface roughness of the polishing pad after dressing, and the sharper the diamond, and the greater the surface roughness of the polishing pad. McAllister [25] and found that a larger wafer-to-pad contact area during polishing reduces the pressure and defects in the CMP process.…”

Uniform Polishing Method of Spherical Lens Based on Material Removal Model of High-Speed Polishing Procedure

“…Moreover, the analysis procedure is very time-consuming, which may become a major obstacle in practice. Based on the literature study, it is found that much research has been performed on the study of the establishment of deterministic kinematic models for flat polishing (such as CMP) [ 14 , 15 , 16 , 18 , 19 , 20 ], but few studies have been found on spherical polishing [ 17 ], especially about the high-speed polishing process. This leads to the fact that the high-speed polishing technology is still limited to small-size or easily polished lenses.…”