“a method for probing multiple four sided, fine pitch ... · design considerations • design for...

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


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


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


Present Day ApproachesPresent Day ApproachesPresent Day Approaches

Vertical Solutions

4 DUT “Parallel”

Cantilever Solutions(AKA: Epoxy Ring)


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


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



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



• 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



• A Better Way:

4 DUT Solutions4 DUT Solutions4 DUT Solutions4 DUT Solutions

1 X 4 2 X 2


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


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


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


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


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


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


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


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 . . .


Questions ? ? ?Questions ? ? ?Questions ? ? ?? ? ? ? ? ? ? ? ?

“a method for probing multiple four sided, fine pitch ... · design considerations • design for...

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