June 14, 2000 1“A Method for Probing . . .“A Method for Probing . . .
2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test WorkshopWorkshopWorkshopWorkshop
“A Method for Probing... Multiple Four Sided, Fine Pitch, Small Pad Devices
. . . using Cantilever Probes”
2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test 2000 SouthWest Test WorkshopWorkshopWorkshopWorkshopWorkshopWorkshopWorkshopWorkshop
“A Method for Probing... “A Method for Probing... Multiple Four SidedMultiple Four Sided, , Fine Fine PitchPitch, , Small Pad DevicesSmall Pad Devices
. . . using Cantilever Probes”. . . using Cantilever Probes”
Presented by: Louis MolinariDirector of Engineering(480) 333-1579 [email protected]
Multi-Site Probing Session
June 14, 2000 2“A Method for Probing . . .“A Method for Probing . . .
OverviewOverviewOverview• Why the need & why now• Present day approaches
• Pros/Cons
• A different approach• Design and characterization results
• Comparisons of “in-line” vs. “diagonal” approaches
• Moving forward . . . design considerations• Manufacturing overview• Review and next step• Questions
June 14, 2000 3“A Method for Probing . . .“A Method for Probing . . .
Why the NeedWhy the NeedWhy the Need
• As with memory; especially DRAM:• Need to reduce test times & cost• Higher throughput• Increased life expectancy of probing solution(s)
– More “Touched Die” per card
• Why NOW ???• More advanced testers and probers
• Speed• Resource availability• Look-up cameras
June 14, 2000 4“A Method for Probing . . .“A Method for Probing . . .
Present Day ApproachesPresent Day ApproachesPresent Day Approaches
Vertical Solutions
4 DUT “Parallel”
Cantilever Solutions(AKA: Epoxy Ring)
June 14, 2000 5“A Method for Probing . . .“A Method for Probing . . .
Present Day ApproachesPresent Day ApproachesPresent Day Approaches
Pros / ConsPros / ConsPros / ConsPros / Cons
Cost Delivery Performance
Vertical Solutions Med - High 4 - 16 wks Med - High
Cantilever Solutions Low - Med 2 - 4 wks Low - Med
Problem Statement:• Primary disadvantage of cantilever is
inconsistency of beam lengths• Resulting in force and scrub variations• Potential issues on smaller pads; ie: Pad Damage
June 14, 2000 6“A Method for Probing . . .“A Method for Probing . . .
A Different ApproachA Different ApproachA Different Approach
• Goals:! Improve cantilever approach, so Force and
Scrub are better controlled,while improving opportunities for probe placement.
• Requirements:! Tighten accuracy requirements to + 0.3 mil max!Reduce probing angle to <10° !Maintain consistency in beam lengths
June 14, 2000 7“A Method for Probing . . .“A Method for Probing . . .
A Different ApproachA Different ApproachA Different Approach
65µ65µ
65µ 65µ
Ideal 0.5 mil error (X,Y)
65µ
65µ
0.3 mil error (X,Y)• Example shown is
with:! 1.0 mil Tip! Yielding a 1.5 mil
total scrub
Additional improvements “may” be accomplished with smaller tip diametersand tighter specs
Address Accuracy and Probe Angle
June 14, 2000 8“A Method for Probing . . .“A Method for Probing . . .
A Different ApproachA Different ApproachA Different Approach
• Typical Force Distribution for Today’s Cantilever Solutions:
Contact Force, diagonal
0.00
0.50
1.00
1.50
2.00
2.50
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65
Pad Numbers
gms/
mil
Series1
Goal: 2 gms/mil
Variation: 30%
Std Dev: 0.18
Area with 30 - 45° angles
Address Probe Force Consistency
June 14, 2000 9“A Method for Probing . . .“A Method for Probing . . .
A Different ApproachA Different ApproachA Different Approach
• A Better Way:
4 DUT Solutions4 DUT Solutions4 DUT Solutions4 DUT Solutions
1 X 4 2 X 2
June 14, 2000 10“A Method for Probing . . .“A Method for Probing . . .
Design CriteriaDesign CriteriaDesign Criteria
• Test die specifications! 0.200 X 0.200! 120 pads/die peripheral! Pad size: 65µ! Pitch: 77µ
• Ring design specifications: (1 x 4; 2 x 2)! 9 and 11 layers! 6 mil wire! 37 and 41 mil maximum tip lengths• Targeted:
! 1.5 gms/mil! 0.6 mil tip diameter
June 14, 2000 11“A Method for Probing . . .“A Method for Probing . . .
Design ApproachDesign ApproachDesign Approach
• A Better Way:! Consistent beam lengths, ALL sides of ALL die
! Results in contact force distribution <10%
! Results in better control of scrub
June 14, 2000 12“A Method for Probing . . .“A Method for Probing . . .
Characterization DataCharacterization DataCharacterization DataContact Force, in-line
0.00
0.50
1.00
1.50
2.00
2.50
1 29 57 85 113
141
169
197
225
253
281
309
337
365
393
421
449
477
Pad Numbers
grm
s/m
il
Series1
Contact Force, diagonal
0.00
0.50
1.00
1.50
2.00
2.50
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65
Pad Numbers
gms/
mil
Series1
30% Variation
10% Variation
Std Dev = 0.18
Std Dev = 0.06
June 14, 2000 13“A Method for Probing . . .“A Method for Probing . . .
Characterization DataCharacterization DataCharacterization Data
Scrub Lengths, in-line
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106
113
120
Pad Numbers
Scru
b (m
il)
Die 1Die 2
Data from 2 DUTS
Tip Diameter, in-line
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106
113
120
Pad Numbers
Diam
eter
(mil)
Die 1Die 2
Data from 2 DUTS
• Results show consistency . . .! Within and between die ! From layer to layer (9 layers)
• Data taken from an Al wafer at:3mil overdrive
• Measured on a: RAM Optical Measurement System
June 14, 2000 14“A Method for Probing . . .“A Method for Probing . . .
Moving ForwardDesign Considerations
Moving ForwardMoving ForwardDesign ConsiderationsDesign Considerations
• Design for manufacturability specifications:! Center to center spacing from
columns to row = 200µ minimum! For ALL four sides of the die
! Minimum pad size = 60! Minimum pitch = 70
! Various exceptions and conditions always need to be reviewed and considered
200µ
200µ
June 14, 2000 15“A Method for Probing . . .“A Method for Probing . . .
Manufacturing OverviewManufacturing OverviewManufacturing Overview
Ceramic Ring
Epoxy
Shim (Shelf)Pt “A” Pt “B”
Pt “B”Pt “A”
• Process is an extension of existing cantilever approaches used in other applications, such as: Multi-Dut DRAM
• Specialized tooling required for alignment and repair of such approaches
Die 1 Die 2
Die 3 Die 4
2 X 2 Approach
June 14, 2000 16“A Method for Probing . . .“A Method for Probing . . .
Review and Next StepReview and Next StepReview and Next Step
• Multiple technologies can probe:“Multiple four sided, fine pitch, small pad devices”
• Cantilever has been capable in the past.With a low cost and quick turn time solution.Yet with variations in it’s results.
• Cantilever solutions can now be manufactured to yield the desired consistency !!!
• Better utilization of prober and reduction in number of touchdowns (In-Line vs. Diagonal)
• Less potential “touch-offs” or “double touches”as compared to a diagonal approach! For the example given: 288 TD vrs 300 TD
of the1100 potential die
June 14, 2000 17“A Method for Probing . . .“A Method for Probing . . .
Review and Next StepReview and Next StepReview and Next Step
• Appropriate “systems” are required to utilize these solutions
• Prober Capability: Look-up Cameras
• Repair Capability: Inverted Alignment Systems
• 1x4 and 2x2 2x4 and beyond . . .
June 14, 2000 18“A Method for Probing . . .“A Method for Probing . . .
Questions ? ? ?Questions ? ? ?Questions ? ? ?? ? ? ? ? ? ? ? ?