Research Results Overview Review of former work on instantaneous fluid film thickness measurements Review of former work on instantaneous fluid film thickness measurements Most recent friction data Most recent friction data Calibration for film thickness measurements Calibration for film thickness measurements Friction and film thickness correlation Friction and film thickness correlation Imaging issues Imaging issues Patterning and profiles for pad Deformation Studies Patterning and profiles for pad Deformation Studies Static images of patterned wafers Static images of patterned wafers Preliminary dynamic pad deformation results. Preliminary dynamic pad deformation results.

Results from last year: Slurry thickness in time The first Instantaneous fluid film thickness measurements in time show some periodicity. The first Instantaneous fluid film thickness measurements in time show some periodicity.

Friction vs Time No apparent pattern at standard run conditions. No apparent pattern at standard run conditions. Pictured below are fiction measurements at “slow” rotation speeds show periodicity. Pictured below are fiction measurements at “slow” rotation speeds show periodicity.

Reproduction of Friction Data Pad/Wafer Rotation = 60 RPM Pad/Wafer Rotation = 60 RPM Slurry Flow = 50 cc/min Slurry Flow = 50 cc/min Friction sample rate = 1000Hz Friction sample rate = 1000Hz Force (V) Time (s)

Accurate Film Thickness Calibration 2 Microscope slides are shimmed with 80  m double stick tape. 2 Microscope slides are shimmed with 80  m double stick tape. The end opposite the tape is assumed to have a thickness of 0. The end opposite the tape is assumed to have a thickness of 0. Slurry is inserted between the slides with know slope. Slurry is inserted between the slides with know slope. Height = 40Ratio - 14

Film Thickness Measurements “Standard Conditions”: Pad/Wafer Rotation = 60 RPM, Slurry Flow = 50 cc/min. “Standard Conditions”: Pad/Wafer Rotation = 60 RPM, Slurry Flow = 50 cc/min.

Film Thickness Measurements “Slow” Rotation Film thickness for pad/wafer rotation speed = 5rpm. Film thickness for pad/wafer rotation speed = 5rpm.

Is there a correlation? Accurately time stamp images. Accurately time stamp images. Time between laser pulses Time between laser pulses Time at which the camera takes the picture Time at which the camera takes the picture Correlate pulse (~2Hz) with Friction (1000Hz) Correlate pulse (~2Hz) with Friction (1000Hz)

Friction and Film Thickness at “Standard” conditions

Extreme Images This image has approximately uniform intensity. There is slurry on top of the wafer creating a dark circle. This image has variable intensity. The dark areas might be bubbles passing beneath the wafer or areas where the pad and wafer are in contact.

Summary of Friction Results Accurately Correlate Friction Accurately Correlate Friction No Apparent Correlation No Apparent Correlation Fluid film thickness is measured locally whereas friction is measured over the entire wafer. Fluid film thickness is measured locally whereas friction is measured over the entire wafer. Images need to be examined individually. A more appropriate region of interest should be selected. Images need to be examined individually. A more appropriate region of interest should be selected.

Pad Deformation Studies Pad Deformation Studies Two Patterning Methods Two Patterning Methods Spin coating with a tape mask Spin coating with a tape mask HF acid etch HF acid etch Observation Method Observation Method Collect Surface Profiles Collect Surface Profiles Static DELIF Imaging Static DELIF Imaging Dynamic DELIF Imaging Dynamic DELIF Imaging

Profilometer Images of HF Etched Wafer 3D Construction 2D Profile

Profilometer Images of Spin Coated Wafer

Static Images of HF Patterned wafer

Static Images of Spin Coated Wafer The difference in the average value of the ratio is.05, corresponding to a 2  m step. The coating seems to chemically weather after prolonged exposure to the slurry.

Dynamic Images of HF Etched wafer Many Images were flooded in around the edges of the wafer. Epoxy made the images grainy. The wafer looked flat during polishing. Post-polishing there was there was little change in step height.

Summary of Pad Deformation There are 2 successful patterning methods. There are 2 successful patterning methods. Static DELIF image data seems to reproduce profilometer data. Static DELIF image data seems to reproduce profilometer data. Dynamic DELIF has not reproduced profilometer data, but the technique is still under development Dynamic DELIF has not reproduced profilometer data, but the technique is still under development

Proposal for next Data Fiction Fiction Why are we not seeing a correlation between friction and film thickness? Why are we not seeing a correlation between friction and film thickness? Develop new method to select region of interest that corresponds to friction measurements Develop new method to select region of interest that corresponds to friction measurements Determine the origin of low intensity regions Determine the origin of low intensity regions Pad Deformation Pad Deformation How accurately can we measure deformation in situ? How accurately can we measure deformation in situ? Dynamic measurements of HF etched and spin coated wafers Dynamic measurements of HF etched and spin coated wafers Develop techniques for attaching the etched wafer to the polisher for better optics. Develop techniques for attaching the etched wafer to the polisher for better optics.