Rapid Diagnostics Using a Prober Based PCA

Sammy MokVeraConnex, LLC

June 7-10, 2009San Diego, CA

Tools for Verifying Connections

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 22

Motivation• Experienced the challenges of building advanced

memory probe cards • How do you ensure your probe card works in

production?– Cards in production deflect differently than PCAs– Testing at multiple temperatures is required– Intermittent connections can not be detected– Life testing with relays does not work

• Test solutions get expensive– Probe counts - 60K+, embedded ICs, card sizes - >480 mm– Need convoluted test flow with custom developed tools

• Need real time and comprehensive diagnostic tools• There has to be a simpler solution

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 33

Challenges• Probe cards can generate >200Kg force &

every test cell can deflect differently– Deflection contributors

• Prober chuck and head plate• Probe cards and their attachment to head plates• ATE test head weight• Temperature distortion (-45 to +200C)

• Significantly reduce the cost of test• How do you test for Cres and electrical

planarity with ICs in the way?

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 44

Objectives / Implementation• Minimize deflection differences of test cells

– Mount switch electronics on probe card in target prober– Use ATE suppliers interface kits to attach to head plate – Use manipulator to support electronics & replicate load– Perform tests at all required temperatures – Measure tip positions using scrub marks on blank wafer

• Reduce cost of test– Faster parallel bussed pin testing– Streamline the test flow – keep on one tool– Minimal cabling and connectors– Scrub mark damage to replace force measurement

• Test through embedded ICS– Any channel can be a logic control channel

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 55

Approach• First target: ATE with large installed base

– Advantest T5375: 96 ZIF connectors, 440 mm • Criteria

– True 4 - point measurements– Control digital ICs– High performance: intermittent & life time testing

• Hot switching & stable solid state switches– Measure passives and relays– Scalable architecture: start at 65,536 channels– Thorough self-test: configuration and communication– Confocal microscope: location & damage = force

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 66

Electronics Hardware• Manipulator to

support pin electronics and match load

• Prototype: Shown directly mounted on head plate of EG prober

Prototype on EG Prober

Probe CardConnectors

ATE Connectors

Probe Card

VeraConnexElectronics

Board

Probe Card Top ViewSide View

Probe CardConnectors

ATE Connectors

Probe Card

VeraConnexElectronics

Board

Side View

``

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 77

Cres Testing: Signal Probes• 4-wire resistance measurement of each probe using probe card

– Use prober to raise blank metalized wafer in contact with all probes– Connect force F+ and sense S+ rails from measurement unit to selected probe– Connect force F- and sense S- from measurement unit to several near by probes– Voltage across F+ to F- limited to < 50mv to not burn through interface layers

Performance Verification• Use system to analyze a 64 site LM4 probe card

to evaluate tool effectiveness in diagnosing problems– Electrical Planarity (on Au and Al wafers)– Cres on 100 touchdowns to Au and Al wafer– Leakage

• Verify measurement speed– More than 300 Cres tests per second

(Data+Reports for presentation in minutes)– Immediate data analysis and capture of images from

electrical results

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 88

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 99

Resistance Repeatability• Pin Card Measurements with shorting board

– 100 Measurements are consistent to within 16 mohms– Values include: Shorting resistance +Traces + Connector

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0.01

37.5

7 67

G2

37.6

2 19

G2

37.6

5 16

G2

37.7

0 68

G2

37.8

3 12

G2

37.9

6 11

3G1

37.1

06 2

4G2

38.3

PPS

170F

38.9

6 11

5G1

38.1

06 2

5G2

40.3

PPS

234F

40.4

1 10

9G1

40.4

8 11

2G1

40.1

01 2

3G2

40.1

09 6

5G2

45.6

0 15

G4

45.6

3 17

G4

45.6

7 18

G4

45.7

1 14

G4

45.8

4 13

G4

45.1

01 2

0G4

45.1

09 2

8G4

47.3

7 10

6G3

47.4

4 10

7G3

47.9

6 11

4G3

47.1

06 2

6G4

48.3

PPS

236F

48.4

1 10

9G3

48.4

8 11

2G3

48.1

01 2

3G4

48.1

09 6

5G4

74.4

1 10

1H5

74.7

0 68

H6

74.7

4 3H

674

.76

5H6

74.7

8 7H

674

.80

8H6

77.9

6 49

H5

77.1

06 2

4H5

79.9

6 50

H5

79.1

06 2

6H5

80.3

7 46

H5

80.4

8 48

H5

80.1

01 2

3H5

169.

3 …16

9.62

19F

616

9.65

16F

616

9.71

14F

616

9.81

9F6

169.

83 1

2F6

169.

96 1

13F5

169.

106

24F6

170.

3 PP

S54F

170.

48 1

04F5

170.

101

21F6

170.

109

29F6

171.

37 1

06F5

171.

44 1

07F5

171.

96 1

14F5

171.

106

26F6

172.

37 1

10F5

172.

44 1

11F5

172.

96 1

16F5

172.

106

27F6

225.

37 3

4A1

225.

44 3

5A1

225.

57 6

7A1

225.

62 1

9A1

225.

65 1

6A1

225.

70 6

8A1

225.

72 1

A122

5.74

3A1

225.

76 5

A122

5.78

7A1

225.

80 8

A122

5.82

10A

122

5.84

13A

1 Del

ta R

esis

tanc

e (M

ax-M

in) (

ohm

s)

Stan

dard

Dev

iatio

n

Test Channels

100X Shorted Cres Repeatability Results - Shorting BoardStdDev

delta Cres

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1010

3X Planarity Results on Au Wafer

0

10

20

30

40

50

60

70

80

90

100

110

Test Channel

Con

tact

Res

ista

nce

(ohm

s)

Au PT4 P2 Au PT5 P2 Au PT6 P2 #N/A API Loaded Planarity

Stepping Cres on Au Wafer (100um OD from 1st touch)

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1111

0

10

20

30

40

50

60

70

80

90

100

110

Test Channel

Con

tact

Res

ista

nce

(ohm

s)

Au SS1 P3 PTres @ Z=26786 Au SS2 P 4 PTres @ Z=26786 Au SS3 P5 PTres @ Z=26786 Au SS4 P6 PTres @ Z=26786 Al SS5 P9 PTres @ Z=26812

Positions withFluctuating Cres

CorrespondingScrub Marks

After 50 steps on Probe Clean™ @ 50um OD

Cres during cleaning on WC wafer

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1212

Die.Pin = 225.74 3A1 / Test Pass = WC Rough StepClean

0

10

20

30

40

50

60

70

80

90

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 45.109 28G4 / Test Pass = WC Rough StepClean

0

10

20

30

40

50

60

70

80

90

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 45.96 113G3 / Test Pass = WC Rough StepClean

0

10

20

30

40

50

60

70

80

90

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 79.96 50H5 / Test Pass = WC Rough StepClean

0

10

20

30

40

50

60

70

80

90

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

After Probe Clean™ + 50 Steps on WC + Probe Clean™

3X Planarity on Au Wafer after clean

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1313

0

10

20

30

40

50

60

70

80

90

100

110

Test Channel

Plan

arity

(1st

Z @

10 o

hms)

(um

)

Au PTa P14 Au PTc P14 Au PTd P14 #N/A API Loaded Planarity

Fewer Fluctuating pins

Insert Chart Animation Video HERE

Animation of Contact Resistance During Planarity TestBefore Cleaning After Cleaning

154 Test Channels

Individual Pin Cres During Planarity Test (Au Wafer @ 75um OD after 1st touch) (Post clean)

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1515

Die.Pin = 40.109 65G2 / Test Pass = Au PTa P14

0

10

20

30

40

50

60

70

80

90

100

-129 -29

-29 21 9 3 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 79.106 26H5 / Test Pass = Au PTa P14

0

10

20

30

40

50

60

70

80

90

100

-129 -29

-29 21 9 3 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 169.84 13F6 / Test Pass = Au PTa P14

0

10

20

30

40

50

60

70

80

90

100

-129 -29

-29 21 9 3 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

Die.Pin = 40.37 110G1 / Test Pass = Au PTa P14

0

10

20

30

40

50

60

70

80

90

100

-129 -29

-29 21 9 3 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

Touchdown Number

Con

tact

Res

ista

nce

(ohm

s)

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1616

Cres Results100 Step Repeatability Results - No stepping (Pos 1) (50um OD on Au6)

0.1

1

10

100

100037

.57

67G

237

.62

19G

237

.65

16G

237

.70

68G

237

.83

12G

237

.96

113G

137

.106

24G

238

.3 P

PS

170F

38.9

6 11

5G1

38.1

06 2

5G2

40.3

PP

S23

4F40

.41

109G

140

.48

112G

140

.101

23G

240

.109

65G

245

.60

15G

445

.63

17G

445

.67

18G

445

.71

14G

445

.84

13G

445

.101

20G

445

.109

28G

447

.37

106G

347

.44

107G

347

.96

114G

347

.106

26G

448

.3 P

PS

236F

48.4

1 10

9G3

48.4

8 11

2G3

48.1

01 2

3G4

48.1

09 6

5G4

74.4

1 10

1H5

74.7

0 68

H6

74.7

4 3H

674

.76

5H6

74.7

8 7H

674

.80

8H6

77.9

6 49

H5

77.1

06 2

4H5

79.9

6 50

H5

79.1

06 2

6H5

80.3

7 46

H5

80.4

8 48

H5

80.1

01 2

3H5

169.

3 P

PS

182F

169.

62 1

9F6

169.

65 1

6F6

169.

71 1

4F6

169.

81 9

F616

9.83

12F

616

9.96

113

F516

9.10

6 24

F617

0.3

PP

S54

F17

0.48

104

F517

0.10

1 21

F617

0.10

9 29

F617

1.37

106

F517

1.44

107

F517

1.96

114

F517

1.10

6 26

F617

2.37

110

F517

2.44

111

F517

2.96

116

F517

2.10

6 27

F622

5.37

34A

122

5.44

35A

122

5.57

67A

122

5.62

19A

122

5.65

16A

122

5.70

68A

122

5.72

1A

122

5.74

3A

122

5.76

5A

122

5.78

7A

122

5.80

8A

122

5.82

10A

122

5.84

13A

1

Test Channels

Cre

s (o

hms)

0

2

4

6

8

10

12

14

16

18

Stan

dard

Dev

iatio

n

MaxMinMedianStdDev

Fluctuation in Cres over repeated steps identifies problem pins

Per Pin Cres Signature over 100 Steps on Au

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1717

45.109 28G4 Max = 7.181 Min = 5.013 Stdev = .7189

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

77.106 24H5 Max = 19.133 Min = 3.752 Stdev = 3.6937

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

79.106 26H5 Max = 19.225 Min = 7.928 Stdev = 2.6221

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

38.109 29G2 Max = 2.717 Min = 2.689 Stdev = .0065

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

Ideal Pin Passing Pin

Intermittent Pin Intermittent Pin

10 Ohm passing limit

Per Pin Cres signature over 100 Steps on Al

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1818

38.109 29G2 Max = 2.647 Min = 2.362 Stdev = .0489

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

45.109 28G4 Max = 99.9 Min = 5.245 Stdev = 15.8795

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

77.106 24H5 Max = 99.9 Min = 2.727 Stdev = 10.0404

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

79.106 26H5 Max = 99.9 Min = 4.243 Stdev = 19.3432

0.1

1

10

100

1 11 21 31 41 51 61 71 81 91Step Number

Cre

s (o

hms)

First Touch Z Sampled During 1 hr Soak

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 1919

Initial Probe card temp = 25°CChuck temp = 85°C

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

0

300

600

900

1200

1500

1800

2100

2400

2700

3000

3300

3600

3900

Time (secs)

Del

ta Z

from

Roo

m te

mp

Posi

tion

(um

)

Soaking with chuck tracking at 0 um ODSoaking with chuck tracking at 50um OD

Soaking at 200um below tip median plane(@25°C)Reference with Chuck and Probe card @25°C

Dynamic First-Touch Z Profiling

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 2020

Chuck temp = 85C

‐90

‐80

‐70

‐60

‐50

‐40

‐30

‐20

‐10

0

10

20

30

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115

Time  (mins)

First T

ouch Z (u

m)

10 min Tracking@ 75umabove1stTouch

10 min Tracking@ 75umabove1stTouch

10 min Tracking@ 75umabove1stTouch

10 min Tracking@ 75umabove1stTouch

90 sec interval with chuckmoved under lookdown camera

60 min Soak @ 200 um below mean 25C tip plane

First Touch @ 25C

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 2121

Results• Demonstrated that the system can collect data

in minutes and provide immediate analysis• Fast electronics integrated into prober opens up

new methods in diagnosing problems– Fast Cres measurements enable collection of individual

pin signatures • Can identify unique problems despite passing Cres• Intermittent Cres can be identified

– Dynamic planarity behavior of probe card can be observed

– Integrated real time data analysis help correlate measurements to problem pins

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 2222

Follow-On Work• Investigate other signatures

– Scrub• Correlation of pin signature to

– Probe card life– Product die test yield

June 7 to 10, 2009June 7 to 10, 2009 IEEE SW Test WorkshopIEEE SW Test Workshop 2323

Acknowledgements• Co-Authors: VeraConnex, LLC

– Frank Swiatowiec– Fariborz Agahdel– Bruce Pettyjohn

• Hyphenated Systems, LLC– Edward Robinson

• Electroglas, Inc.– Steve Martinez– Jonathan Halderman

• Aehr Test– Chris Buckholtz