Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications

We investigated the tribological, thermal, kinetic, and surface microtextural characteristics of chemical mechanical polishing (CMP) of 300 mm p-type <100> prime silicon wafers (and their native oxide) at various pressures, sliding velocities, and starting platen temperatures. Results showed t...

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Main Authors: Michelle Yap, Catherine Yap, Yasa Sampurno, Glenn Whitener, Jason Keleher, Len Borucki, Ara Philipossian
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Electronic Materials
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Online Access:https://www.mdpi.com/2673-3978/6/1/1
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author Michelle Yap
Catherine Yap
Yasa Sampurno
Glenn Whitener
Jason Keleher
Len Borucki
Ara Philipossian
author_facet Michelle Yap
Catherine Yap
Yasa Sampurno
Glenn Whitener
Jason Keleher
Len Borucki
Ara Philipossian
author_sort Michelle Yap
collection DOAJ
description We investigated the tribological, thermal, kinetic, and surface microtextural characteristics of chemical mechanical polishing (CMP) of 300 mm p-type <100> prime silicon wafers (and their native oxide) at various pressures, sliding velocities, and starting platen temperatures. Results showed the dominant tribological mechanism for both native oxide and silicon polishing to be boundary lubrication. Using frictional data, we pinpointed the exact time that corresponded to the total removal of the native oxide and the onset of silicon polishing. This allowed us to separately characterize removal rates of each layer. For native oxide, while the rate depended on temperature, the presence of a temperature-independent shear force threshold and the low observed rates suggested that its removal by the slurry was dominantly mechanical. In contrast, for silicon polish, the absence of a distinctive shear force threshold and the fact that, for the same set of consumables, rates were more than 200 times larger for silicon than for native oxide suggested a dominantly chemical process with an average apparent activation energy of 0.34 eV. It was further confirmed that rate selectivity between native oxide and PE-TEOS based SiO<sub>2</sub> control wafers was around 1 to 7, which underscored the importance of being able to directly measure native oxide removal rates. In all cases, we achieved excellent post-polish surfaces with <i>S<sub>a</sub></i> and <i>S<sub>q</sub></i> values of below 1 nm. Due to thermal softening of the thermoplastic pad at elevated temperatures, which we confirmed via dynamic mechanical analysis, overall process vibrations were significantly higher when platen heating was employed.
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spelling doaj-art-0569cc1ee87f40eea55543e36da567f12025-08-20T02:11:01ZengMDPI AGElectronic Materials2673-39782025-01-0161110.3390/electronicmat6010001Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding ApplicationsMichelle Yap0Catherine Yap1Yasa Sampurno2Glenn Whitener3Jason Keleher4Len Borucki5Ara Philipossian6Araca, Inc., Tucson, AZ 85750, USAAraca, Inc., Tucson, AZ 85750, USAAraca, Inc., Tucson, AZ 85750, USAFujimi Corporation, Tualatin, OR 97062, USADepartment of Chemistry, Lewis University, Romeoville, IL 60446, USAAraca, Inc., Tucson, AZ 85750, USAAraca, Inc., Tucson, AZ 85750, USAWe investigated the tribological, thermal, kinetic, and surface microtextural characteristics of chemical mechanical polishing (CMP) of 300 mm p-type <100> prime silicon wafers (and their native oxide) at various pressures, sliding velocities, and starting platen temperatures. Results showed the dominant tribological mechanism for both native oxide and silicon polishing to be boundary lubrication. Using frictional data, we pinpointed the exact time that corresponded to the total removal of the native oxide and the onset of silicon polishing. This allowed us to separately characterize removal rates of each layer. For native oxide, while the rate depended on temperature, the presence of a temperature-independent shear force threshold and the low observed rates suggested that its removal by the slurry was dominantly mechanical. In contrast, for silicon polish, the absence of a distinctive shear force threshold and the fact that, for the same set of consumables, rates were more than 200 times larger for silicon than for native oxide suggested a dominantly chemical process with an average apparent activation energy of 0.34 eV. It was further confirmed that rate selectivity between native oxide and PE-TEOS based SiO<sub>2</sub> control wafers was around 1 to 7, which underscored the importance of being able to directly measure native oxide removal rates. In all cases, we achieved excellent post-polish surfaces with <i>S<sub>a</sub></i> and <i>S<sub>q</sub></i> values of below 1 nm. Due to thermal softening of the thermoplastic pad at elevated temperatures, which we confirmed via dynamic mechanical analysis, overall process vibrations were significantly higher when platen heating was employed.https://www.mdpi.com/2673-3978/6/1/1chemical mechanical polishingsilicon polishnative oxide polish
spellingShingle Michelle Yap
Catherine Yap
Yasa Sampurno
Glenn Whitener
Jason Keleher
Len Borucki
Ara Philipossian
Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
Electronic Materials
chemical mechanical polishing
silicon polish
native oxide polish
title Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
title_full Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
title_fullStr Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
title_full_unstemmed Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
title_short Tribological, Thermal, Kinetic, and Surface Microtextural Characterization of Prime p-Type <100> Silicon Wafer CMP for Direct Wafer Bonding Applications
title_sort tribological thermal kinetic and surface microtextural characterization of prime p type 100 silicon wafer cmp for direct wafer bonding applications
topic chemical mechanical polishing
silicon polish
native oxide polish
url https://www.mdpi.com/2673-3978/6/1/1
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