Quantitative in situ measurement of asperity compression under the wafer during polishing
Download
1 / 14

Quantitative In-Situ Measurement of Asperity Compression Under the Wafer During Polishing - PowerPoint PPT Presentation


  • 73 Views
  • Uploaded on

Quantitative In-Situ Measurement of Asperity Compression Under the Wafer During Polishing. Caprice Gray MRS Spring Meeting San Francisco, CA March 30, 2005. Overview. Introduction Experimental Setup Polisher Dual Emission Laser Induced Fluorescence Pad Compression Experiments and Results

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Quantitative In-Situ Measurement of Asperity Compression Under the Wafer During Polishing' - thor


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Quantitative in situ measurement of asperity compression under the wafer during polishing

Quantitative In-Situ Measurement of Asperity Compression Under the Wafer During Polishing

Caprice Gray

MRS Spring Meeting

San Francisco, CA

March 30, 2005


Overview
Overview Under the Wafer During Polishing

  • Introduction

  • Experimental Setup

    • Polisher

    • Dual Emission Laser Induced Fluorescence

  • Pad Compression Experiments and Results

    • Static Compression

    • Dynamic Compression

  • Conclusion


Introduction
Introduction Under the Wafer During Polishing

  • DELIF is used to collect grayscale images that represent properties under the wafer during polishing

    • pH, temperature, fluid layer thickness

  • Previous thickness measurement

    • time averaged

    • low spatial resolution

  • New DELIF Setup

    • Laser enables instantaneous imaging

    • Larger distance between lens and CCD – 4 mm/pixel

  • In these experiments we use fluid thickness measurements to infer what is happening to pad asperities during polishing


Polishing setup

Motor Under the Wafer During Polishing

Wafer

Platen

Steel Table

RotoPol-31

Force Table

Polishing Setup


Delif
DELIF Under the Wafer During Polishing


Why examine 2 emissions

Pad Under the Wafer During Polishing

Slurry

Why Examine 2 Emissions?

Ratio

=

Division of 2 images cancels variations

in image source intensity


Experiments
Experiments Under the Wafer During Polishing

  • Pads: flat Fruedenberg FX9

    • Global vs. Local topography

  • Static: flat glass wafer

  • Dynamic: etched glass wafer


Static pad compression
Static Pad Compression Under the Wafer During Polishing

  • 2 Images were taken in a single section of the pad.

    • 0 kPa

    • 70 kPa

  • 17 total sections were imaged and analyzed.


Histogram analysis
Histogram Analysis Under the Wafer During Polishing

  • The asperity size distribution is the same shape as the fluid layer thickness distribution.

  • When force is applied to the wafer, the distribution changes both shape and location.

  • Standard deviation comparison → pad compression

  • Peak location → fluid layer thickness.

  • Compression factor: e


Static compression results
Static Compression Results Under the Wafer During Polishing


Dynamic pad compression
Dynamic Pad Compression Under the Wafer During Polishing

  • Two wafers were etched and contain square wells

    • 14.5 mm deep

    • 27 mm deep

  • Asperities can expand under these wells.

  • Histograms from regions 1 and 2 are compared

  • Run Conditions:

    • Pad/wafer rotation: 30 RPM

    • Continuous conditioning

    • Slurry flow: 50 cc/min

    • Force applied to wafer: 10 kPa


Dynamic results
Dynamic Results Under the Wafer During Polishing

(7mm)


Conclusions
Conclusions Under the Wafer During Polishing

  • DELIF can be used to measure slurry film thickness with asperity scale resolution.

  • Over the 6 mm2 regions imaged, Different amounts of fluid can be displaced due to the same applied global forces.

  • Pad topography deformation can be inferred from fluid layer thickness measurements.

    • During a static application of force, local pad compression is roughly linearly related to the amount of fluid displaced by the compression

    • In the dynamic case, asperity expansion into 27 mm deep wells was greater than expansion into 14.5 mm deep wells.


Acknowledgements
Acknowledgements Under the Wafer During Polishing

  • Tufts

    • Professor Chris Rogers

    • Professor Vincent P. Manno

    • Dan Apone

    • TUFTL

  • Intel Corporation

    • Chris Barns

    • Mansour Moinpour

  • Cabot Microelectronics

    • Sriram Anjur

  • University of Arizona

    • Ara Philipossian


ad