Comprehensive Approach to Control Contact Resistance Instability and - - PowerPoint PPT Presentation

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Comprehensive Approach to Control Contact Resistance Instability and - - PowerPoint PPT Presentation

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Comprehensive Approach to Control Contact Resistance Instability and Improve First Pass Yield of Bumped Devices Atsushi Mine Jerry J. Broz, Ph.D. Joe Foerstel International Test Solutions Phill Mai Sean Chen 1475 Terminal Way, Ste. D JEM

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SLIDE 1

Atsushi Mine Phill Mai

JEM

3000 Laurelview Court Fremont, CA 94538

Comprehensive Approach to Control Contact Resistance Instability and Improve First Pass Yield of Bumped Devices

2005 SouthWest Workshop June 5 to 8, 2005

Jerry J. Broz, Ph.D.

International Test Solutions

1475 Terminal Way, Ste. D Reno, Nevada 89523

Joe Foerstel Sean Chen

Altera Corporation

101 Innovation Drive San Jose, CA 95134

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SLIDE 2

06/07/2005 SouthWest Test Workshop 2005 2

Overview

  • Introduction
  • Objectives / Approach
  • Methodology Overview
  • Implementation / Characterization
  • Summary
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SLIDE 3

06/07/2005 SouthWest Test Workshop 2005 3

Evaluation Goals

  • To determine the initial time zero path resistance of

the VS crown probe card, and monitor that same path resistance after various amounts of die had been sorted.

  • To compare the performance of current standard

VS flat tip technology against the new VS crown tip in terms of wafer yield.

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SLIDE 4

06/07/2005 SouthWest Test Workshop 2005 4

VS-Series Probe (Crown)

  • Newly developed spring probe design
  • Achieves precise probe position and planarity

Crown Tip Shape Guide Plate Stopper

VS Series

Picture of the Probe

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SLIDE 5

06/07/2005 SouthWest Test Workshop 2005 5

Probe Mark

Contact Concept

I mage of the Contact Point Crown Probe Tip

Stable CRES by lower contact force with minimal probe mark.

The ridge of the crown probe tip translates vertical force into radial force.

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SLIDE 6

06/07/2005 SouthWest Test Workshop 2005 6

VS Crown Tip Probe Mark Images

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SLIDE 7

06/07/2005 SouthWest Test Workshop 2005 7

VS Crown Tip Probe Mark Images

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SLIDE 8

06/07/2005 SouthWest Test Workshop 2005 8

Microscope Images of VS Crown Tip Probe Marks

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SLIDE 9

06/07/2005 SouthWest Test Workshop 2005 9

Probe Mark Size Comparison

  • Crown Tip Marks vs. Flat Tip Bump Deformation
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SLIDE 10

06/07/2005 SouthWest Test Workshop 2005 10

Side View Comparison Of Probe Marks

Flat Tip Crown Tip

50 um 100 um 50 um 100 um 140 um

130 um dia. 140 um dia. Speced. 111 um high measured Actual probe mark location VSC 2 Probe Head Bump Die Surface

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SLIDE 11

06/07/2005 SouthWest Test Workshop 2005 11

VS Crown Probe After Sorting 12 Wafers

Non-destructive on-line cleaning is needed to keep the contact surfaces debris free. VS Crown Probe VS Crown Probe VS Crown Probe VS Crown Probe VS Crown Probe

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SLIDE 12

06/07/2005 SouthWest Test Workshop 2005 12

Path Resistance Measurement

  • Shorted Probe Card PCB used to zero out the

resistance measurements of Test Head and Test Head Cables.

  • VS crown tip probe card used to probe a shorted

wafer, using 150 um OD.

  • Resistance measurements taken at 3 minute

intervals, while resting on a die, no Z-up or Z-down in between.

  • Zero out resistance measurements subtracted out

to acquire actual path resistance.

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SLIDE 13

06/07/2005 SouthWest Test Workshop 2005 13

Yield Comparison

  • Use VS flat tip and VS crown tip to probe the same

wafers.

  • Perform selective resort (resorting bad dice only)

with both technologies to achieve maximum yield for comparison.

  • Inspect VS crown tip probe marks.
  • Inspect VS crown tip probes to compare bump

residue build-up.

  • Measure Planarity and Contact Resistance using

PRVX.

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SLIDE 14

06/07/2005 SouthWest Test Workshop 2005 14

Testing Parameters

  • Same tester and prober used throughout the

experiments.

  • VS Flat Tip parameters

– Probing: 175um OD – Cleaning: 50um OD, 12 times every 50 dice

  • Cleaning medium – 3M 1um lapping film
  • VS Crown Tip parameters

– Probing: 150um OD – Cleaning: 100um OD, once every wafer

  • Cleaning medium – Probe Polish 99, filled cleaning polymer
  • Due to tip shape requirements a lapping film cannot be used
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SLIDE 15

06/07/2005 SouthWest Test Workshop 2005 15

Physical Path Measured for Resistance

Epoxy Epoxy Probe Pin Probe Head 6.3 mil Copper Wire PCB Cross-sectional View Shorted Wafer Test Head Connectors Path Resistance measured outlined by Blue Arrows. Signal Ground

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SLIDE 16

06/07/2005 SouthWest Test Workshop 2005 16

Path Resistance, 1st Die Probed

VS Crown Tip Second Resistance Reading Single TD, Four Readings over 3 min. intervals, 1st Die Probed

  • 1.00
  • 0.50

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 50 101 152 202 Tester Channel Resistance (ohm) T0 T1 T2 T3 AVG Resistance: 1.075 ohm

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SLIDE 17

06/07/2005 SouthWest Test Workshop 2005 17

Path Resistance, 2nd Die Probed

Double TD, Four Readings at 3 min. Intervals, 2nd Die Probed

  • 1.00
  • 0.50

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 50 101 152 202 Tester Channel Resistance (ohm) T0 T1 T2 T3 AVG Resistance: 0.998 ohm

VS Crown Tip Second Resistance Reading

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SLIDE 18

06/07/2005 SouthWest Test Workshop 2005 18

Path Resistance, 2754th Die Probed

Resistance Reading After Probing 2754 Die Single TD, Four readings over 3 min. Intervals

  • 1.00
  • 0.50

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 50 101 152 202 Tester Channel Resistance (ohm) T0 T1 T2 T3 AVG Resistance: 1.103 ohm

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SLIDE 19

06/07/2005 SouthWest Test Workshop 2005 19

Average Path Resistance

  • 25 Die Tested in a row, with no Cleaning

VS Crown Tip Average Path Resistance 25 Die in a row, no cleaning

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 D17 D18 D19 D20 D21 D22 D23 D24 D25 Die # on Shorted Wafer Resistance (ohm) AVG MAX

  • pen found on 1 pin on die 18 (removed

from data)

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06/07/2005 SouthWest Test Workshop 2005 20

Mechanical Performance Characterization

  • Bench-top Materials Testing System

– Assess cleaning material performance. – Evaluate applied load characteristics of probe.

High Resolution Camera Precision Z-stage High Magnification Oblique Lens

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SLIDE 21

06/07/2005 SouthWest Test Workshop 2005 21

Mechanical Performance Characterization

  • High resolution and video imaging
  • Synchronized load vs. overtravel data acquisition

High Magnification and High Resolution Imaging

50-gram Load Cell with Cleaning Material Installed onto Platen High Magnification Oblique Lens Probes

VS Crown Tip 5 Probes on Probe Polish 150-um Z-overtravel

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SLIDE 22

06/07/2005 SouthWest Test Workshop 2005 22

Probe Contact with Bump

Compression Load (grams) 1 x VS Crown Tip Probe at 150um OT

  • n Solder Bump Material

VS Crown Tip Probes on Bump 150-um Z-overtravel VS Crown Tip Probes on Bump 150-um Z-overtravel

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SLIDE 23

06/07/2005 SouthWest Test Workshop 2005 23

Probe Clean to Visualize Penetration

Crown tip penetrates into polymer layer Spring Engages

Compression Load (grams) 1 x VS Crown Tip Probe at 150um OT

  • n Probe Clean Material

VS Crown Tip Probe Cleaning 150-um Z-overtravel VS Crown Tip Probes on Probe Clean 150-um Z-overtravel

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SLIDE 24

06/07/2005 SouthWest Test Workshop 2005 24

5 Probes on Probe Polish 99

Compression Load (grams)

Crown tip penetrates into polymer layer Spring Engages

5 x VS Crown Tip Probe at 150um OT

  • n Probe Polish Material

VS Crown Tip Probes on Probe Polish 99 150-um Z-overtravel VS Crown Tip Probes on Probe Polish 99 150-um Z-overtravel

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06/07/2005 SouthWest Test Workshop 2005 25

VS Crown Tip Probes After Online Cleaning

Cleaned Once per Wafer Cleaned Once per Wafer

VS Crown Probe VS Crown Probe

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SLIDE 26

06/07/2005 SouthWest Test Workshop 2005 26

Yield Comparison

2 4 6 8 10 12 14 16 18 20 22 24 2 4 6 8 10 12 14 16 18 20 22 24 wafer # yield (dpw) 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% recovery (%) WS1 RS1 RS%

VSCC2 Split VSC Split

Final Yield Equal Good Dice Per Wafer Equal

VS Crown Tip vs. VS Flat Tip

VS Crown Tip VS Flat Tip

Final Yield Equal Good Die per Wafer Equal

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SLIDE 27

06/07/2005 SouthWest Test Workshop 2005 27

Planarity Reading from PRVX

  • 1.500
  • 1.000
  • 0.500

0.000 0.500 1.000 1.500 1 26 51 76 101 126 151 176 201 226 251 276 301 Virtual Pad # Mils

VS Crown Point Probe Card Planarity, I/O Only, 2754 Die Sorted

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SLIDE 28

06/07/2005 SouthWest Test Workshop 2005 28

Contact Resistance Reading from PRVX

0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 1 26 51 76 101 126 151 176 201 226 251 276 301 Virtual Pad # Ohms

VS Crown Point Probe Card Contact Resistance, I/O Only, 2754 Die Sorted

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06/07/2005 SouthWest Test Workshop 2005 29

Summary

  • VS crown tip probe path resistance is on the same order as

standard VS flat.

  • VS crown tip Path Resistance holds stable after 2500+ die

sorted and non-destructive cleaning only after each wafer.

  • VS crown tip is able to achieve maximum yield at first sort,

with lower resort recovery.

  • Probe marks generated by VS crown tip show minimal

disturbance to the bump structure, compared to VS flat tip and other vertical probing technologies.

  • On-line cleaning with Probe Polish 99 was effective in

keeping the crown tip clean without affecting the tip geometry in order to maintain consistent yield.

  • Planarity remained at +/-1mil after probing 12 wafers.
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SLIDE 30

06/07/2005 SouthWest Test Workshop 2005 30

Acknowledgements

  • Patrick Mui – Engineering Manager, JEM-America
  • Altera Test Engineering
  • JEM-Japan Test Engineering
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SLIDE 31

06/07/2005 SouthWest Test Workshop 2005 31

SWTW – 2005 Thank you for your attention Questions ???