Application of the Stribeck+ Curve in Silicon Dioxide Chemical Mechanical Planarization

Abstract

The Stribeck+ curve was successfully applied to silicon dioxide chemical mechanical planarization processes to characterize the tribology of such processes under different process conditions and consumables. Results showed that the Stribeck+ curve was capable of rapidly determining and differentiating the tribological mechanism among all cases studied in this manuscript. The Stribeck+ curve could indicate process stability as shown by the spread of the COF vertical clusters. The Stribeck+ curve also confirmed a previously known effect that the greater the ratio of pad's up-features to the total pad area, the greater the probability of wafer hydroplaning. This work underscore the importance of a new method for determining an “improved” Stribeck curve (referred as the “Stribeck+ curve”) while dramatically reducing the amount of consumables and time required to obtain the curve through traditional means.

Effect of Conditioning and Slurry Application Method on Silicon Dioxide Removal Rates Using a Ceria-Based Chemical Mechanical Planarization Slurry

“…Furthermore, CMP processes using a "reverse" ceria slurry show a completely different tribological behavior as compared to processes with standard silica-based slurries where only vertical COF clusters were observed by our team. 28 This indicates that, for silica-based slurries, the actual v/P (i.e. downforce) varies only slightly while for ceria slurries, downforce fluctuations are roughly equivalent (or even greater than) shear force fluctuations.…”

A review on chemical and mechanical phenomena at the wafer interface during chemical mechanical planarization

“…Mullany and Byrne experimentally and theoretically investigated the effect of slurry film thickness on COF during Si wafer polishing in the mixed lubrication region [30], showing that the removal rates of the Si wafer decrease with increasing Hersey number. However, the traditional Stribeck curve fails to explain the lubrication phenomena, while COF and downforce fluctuated significantly during polishing because of the so-called stick-slip phenomena [31,32]. Han et al developed a Stribeck+ curve involving instantaneous process valuables [31,32] (measured shear force and downforce, calculated, and recorded COF), instead of using a constant of shear force and downforce throughout the polishing process, and successfully explained the Stribeck+ curves for SiO 2 [31], Cu [32], and W CMP [32] using various combinations of CMP slurries and pads.…”

Correlating Coefficient of Friction and Shear Force to Platen Motor Current in Tungsten and Interlayer Dielectric Chemical Mechanical Planarization at Highly Non-Steady-State Conditions

“…During the past 7 years, our research group has performed several tribological studies during which we have generated Stribeck+ curves (56,57) using a single 300-mm blanket wafer (i.e. deposited with CVD tungsten, ECP copper or PETEOS-based silicon dioxide films) in an effort to shed additional fundamental light on the contact mechanism(s) in CMP.…”

“…deposited with CVD tungsten, ECP copper or PETEOS-based silicon dioxide films) in an effort to shed additional fundamental light on the contact mechanism(s) in CMP. Results of most of these studies have been published previously (56,57) where, in parallel with collecting shear and normal force data at 1,000…”