Kinematic Prediction and Experimental Demonstration of Conditioning Process for Controlling the Profile Shape of a Chemical Mechanical Polishing Pad

Hanchul Cho,Hyoungjae Kim,Doyeon Kim,Taekyung Lee

doi:10.3390/app11104358

Hanchul Cho, Hyoungjae Kim + Show 2 more

Open Access

https://doi.org/10.3390/app11104358

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Journal: Applied sciences	Publication Date: May 11, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Korea Institute of Industrial Technology

Abstract

The uniformity of the wafer in a chemical mechanical polishing (CMP) process is vital to the ultra-fine and high integration of semiconductor structures. In particular, the uniformity of the polishing pad corresponding to the tool directly affects the polishing uniformity and wafer shape. In this study, the profile shape of a CMP pad was predicted through a kinematic simulation based on the trajectory density of the diamond abrasives of the diamond conditioner disc. The kinematic prediction was found to be in good agreement with the experimentally measured pad profile shape. Based on this, the shape error of the pad could be maintained within 10 μm even after performing the pad conditioning process for more than 2 h, through the overhang of the conditioner.

Highlights

Chemical mechanical polishing (CMP) is one of the representative semiconductor processes, and is the only process closely related to mechanical motion in semiconductor manufacturing processes [1]
The conditioning process was carried out with the same device configuration a Figure 4a shows a schematic of the kinematic model related to the rotation of the conditions as above, and the pad was conditioned for 10 min with a conditioning load conditioner disc, the sweep of the conditioning arm, and the rotation of the pad, where
Results integrating the trajectory made in a certain area where the working diamond abrasives We developed a prediction simulation visualizefor thethe center of of thedx conditioning are defined

Summary

Introduction

Chemical mechanical polishing (CMP) is one of the representative semiconductor processes, and is the only process closely related to mechanical motion in semiconductor manufacturing processes [1]. A conditioning process using a diamond conditioner is applied to maintain a constant roughness of the pad surface [4,5]. To ensure the final quality of the wafer surface, reproducibility of the polishing rate, and reproducibility of the wafer shape, it is necessary to maintain the roughness of the pad and the pad shape constant throughout the conditioning process [8]. The trajectory of the diamond abrasives that wear the pad is determined by the relative motion comprising the rotational motion of the pad and the conditioner and the sweep motion of the conditioning arm. We predicted the trajectory of diamond abrasives based on the relative motion of three factors: pad rotation, conditioner rotation, and sweep speed. A condition in which the pad could continuously maintain its initial shape was derived, and the maximum height deviation was 10 μm or less despite performing the conditioning process for more than 2 h

Conditioning Process and Pad Profile Measurement

Pad Wear Shape Simulation

Results

Conditioner

Trajectory

11. Schematic of the in the contact area and pressure to the overhang

4.4.Summary