Thinning of IC chips - IEEEewh.ieee.org/soc/cpmt/presentations/cpmt1001b.pdf · Thinning of IC...

SCV Chapter, CPMT Society, IEEE January 28, 2010

www.cpmt.org/scv

CPMT-SCV Luncheon TalkJan 28, 2010

[email protected]

1

Thinning of IC chipsAnnette Teng

CORWIL TECHNOLOGY CORP.1635 McCarthy Blvd.Milpitas, CA 95135


[email protected]

2

CONTENT• Industry Demand for thinness• Method to achieve ultrathin dies• Mechanical testing of ultrathin die• Die strength variation source• Methods to achieve strong ultrathin dies• Assembly of Ultrathin dies

– Die Attach Films– Interconnection


www.cpmt.org/scv


[email protected]

3

Reasons to go thin•Decrease street width•Stackable 3D packaging•Smart cards•Improved Heat dissipation•Better electrical performance•Higher speeds

Ultra Paper thinEmbedded packagingWearable packaging

-AppliquesSkin patch

ImplantableFoldable 3D die

-cylinders-cones

-origami


[email protected]

4iNEMI RoadmapInternational Electronic Manufacturing InitiativeInternational Electronic Manufacturing Initiative


www.cpmt.org/scv


[email protected]

5


[email protected]

6


www.cpmt.org/scv


[email protected]

7

STATSchipPACECTC 200950um flip chip


[email protected]

8

BACKGRIND

SAW

PatternedFull thickness

WaferWash wafer

Die Pick and place

Singulate/dicingLaser or Blade

Mount dicing tape on backside

of wafer

Apply front side tape Backgrind Wafer

Remove front side tape

Conventional Flow for Wafer Thinning(DAG)


www.cpmt.org/scv


[email protected]

9

DAG Results:LOW YIELD

• Warpage & curl • Non conformal• Transport challenge• Storage challenge• Lamination challenge


[email protected]

10

DBG DAG

DBG Conventionalmethod

Dice Before Grind

FlowComparison


www.cpmt.org/scv


[email protected]

11

Final thickness

Dice Before Grind Method

Removed thickness

Trench depth

Singulation Depth

Front side tape

Fine grind>2000

Rough grind 300 grit


[email protected]

12

Results• No Wafer Warpage & curl • No Wafer Breakage • Conformal• Transportable• Storable• Easy to Laminate• Easier to bond/debond


www.cpmt.org/scv


[email protected]

13

32um after DBG with Polygrind wheel

Sidewall FlawsPunctures


[email protected]

14

15um silicon dieattached to packageby 25um DAF. 20um gold wire bond


www.cpmt.org/scv


[email protected]

15

L

radius

2 Point Test

width

F

T=0.150

4 Point Test

width T=0.150

l

r=0.025

F

Strength = -------------3F*length

width*thickness2


2*width*thickness2

width T=0.150

L= 0.570mm

r=0.025F

3 Point Test

Thin die StrengthCharacterizationTechniques


[email protected]

16

Plate on Elastic Foundation Test (PEFT)

1.4mm silicone

Point Load test (PLT)

M.Y.Tsai, ASE et alRadius 0.1; 0.25; 0.3mm

Radius 0.1;0.25;0.3mm

1.4mm silicone

Radius 0.1;0.25;0.3mmRadii (ball, ring)

Ball & Ring Test

diameter

Fracture strength Test Methods


www.cpmt.org/scv


[email protected]

17

Relative Strength

0

200

400

600

800

051015202530

Die thickness(mils)

0

50

100

150

200

250

300Br

eaking

-Stre

ngth

1234567Thickness (µm), Ball-Ring-Method, only ground, backside untreated


2*width*thickness2


[email protected]

18

0

200

400

600

800

1000

1200

1400

1600

1800

0.0T 0.1T 0.2T 0.3T

Ratio of sidewall crack to die thickness

MPascal

Effect of flaw size on Die strengthSilicon Dice after grind (DAG) .125mmThick


www.cpmt.org/scv


[email protected]

19

0

200

400

600

800

1000

1200

1400

0.0T 0.1T 0.2T 0.3T 0.4T

MPascal

Effect of flaw size on strengthSilicon DBG 0.150mm thick


[email protected]

20

0

100

200

300

400

500

600

700

800

A B C D E F G H

Die strength

(

Mpa

)

Dramatic strength variation


www.cpmt.org/scv


[email protected]

21

Die Strength of various 0.150mm thick .670mm RFID dies

386.51412.68

519.83

352.93

273.72252.24

401.61421.8

449.93

0

100

200

300

400

500

600

700

Finish and dicing method

Fracture

strength

in N/mm2


[email protected]

22

0

2

4

6

8

10

12

254-314 314-374 374-433 433-493 493-552 552-612 612-671

Die strength in MPa

Frequency

Distribution plot -sample size 50Group H (CMP-blade saw)


www.cpmt.org/scv


[email protected]

23

0

2

4

6

8

10

12

254-314 314-374 374-433 433-493 493-552 552-612 612-671

Die strength in MPa

Frequency

Distribution plot -sample size 50Group H (CMP-blade saw)


[email protected]

24

0

2

4

6

8

10

12

14

16

123 to 164

164 to 205

205 to 246

246 to 287

287 to 327

327 to 368

368 to 409

Die strength of singulated random dies from 1 wafer

Frequency

Distribution plot of 2000grit etched group


www.cpmt.org/scv


[email protected]

25

Y channelBlade feed direction

Most common chipout is last side rip of the Smaller piece

•Snaps off •Shifts away from blade •Vibrates more

X channelblade step direction

Bigger

Smal

ler

blade.150mm

Examples of Surface defects


[email protected]

26

0

200

400

600

800

1000

1200

1400

-10 35 80

Angle from Anvil

MPa

Large fracture strength variations within 1 wafer


www.cpmt.org/scv


[email protected]

27

SIDEWALL 0.250mm

Laser generated roughness

Laser ablation


[email protected]

28SIDEWALL 0.250mm

Laser scribe and break

SIDEWALL 0.250mm

Laser Stealth and expand


www.cpmt.org/scv


[email protected]

29

PERSONAL PREFERENCE - VISUAL REJECT

ACCEPT


[email protected]

30

Examples of Surface Flaws


www.cpmt.org/scv


[email protected]

31

Total thickness variation of a thinned wafer


[email protected]

32

Wafer Thinning Target

Thickness

8 m TTV to thickness ratio

TTV effect on 3 pt bend die

strength

0.150 mm 5.3%(0.146-0.154mm)

10.6%

0.100 mm 8%(0.096-0.104mm)

16.0%

0.050 mm 16%(0.046-0.054mm)

32.0%

TTV HAS MAJOR IMPACT ON ULTRATHIN DIE


www.cpmt.org/scv


[email protected]

33

Source:Disco


[email protected]

34

5 sided smoothening


www.cpmt.org/scv


[email protected]

35

Full thickness Wafer

Wash wafer

Die Pick and place


of wafer

Apply front side tape

Backgrind Wafer

Remove front side tapeBlade or

Laser Saw

DAF FLOW

DAF


[email protected]

36

DBG Conv.

DBG

DAG

FlowComparison

Of DBGForDAF

DAF

DAF

3 lamination2 detape2 singulation

2 lamination1 detape1 singulation

Half Cut Dicer2 lamination1 detape2 singulation


www.cpmt.org/scv


[email protected]

37

37

DAF services are easily integrated into existing line-automated thin wafer grind-automated DAF mounting-automated dicing with DAF

-automated die attach with DAF


[email protected]

38

38

Film Over Wire (FOM) tape

Adhesive with viscosity so low that it will wrap around gold wire loops when heated to 150oC

Heat Stage


www.cpmt.org/scv


[email protected]

39

39

Amkor


[email protected]

40

Half Cut Dicer2 lamination1 detape2 singulation


www.cpmt.org/scv


[email protected]

41Full thickness Wafer

Wash wafer

Die Pick and place


of wafer

Apply front side tape Backgrind Wafer

Remove front side tape

Blade or Laser Saw

DAF FLOW

DAF


[email protected]

42

Reasons to use DAF1. NO VOIDS2. NO PINHOLES3. NO BUBBLES4. NO DIE TILT5. UNIFORM BONDLINE6. NO FUMES7. HIGH THROUGHPUT

1. Memory DRAM/SRAM2. High adhesion to all surfaces3. Pass MSL; Pass Reliability testing4. Strength improvement for ultrathin die5. Compact Medical prosthetics6. For laminating ultrathin dies7. Vertical Stacking8. Die on flex/tape/film9. Wafer bonding

pasteDAF


www.cpmt.org/scv


[email protected]

43

DAF LIMITATIONSSuppliers1. Hitachi-2. Lintec Adwill (UV)3. Nitto Denko 4. Nippon Steel5. Hysol/Ablestik

1. Not quite DBG compatible2. Not electrically conductive3. Not thermally conductive4. Not required for non stack pkg


[email protected]

44

Ultrathin die Interconnect

17um die IMEC, Belgium140um package thickness


www.cpmt.org/scv


[email protected]

45

Ultrathin bumping is after thinning

Applied Physics LabJohns Hopkins Univ.ECTC 2009


[email protected]

46

Summary of Ultrathin Technology• Dice Before Grind• Thickness as low as 10um available• High flexibility• High scatter of die strength

– After DAG laser or blade saw– After DBG– Independent of test methods– Predictable by 5 side inspection

• Chemical Smoothening of 5 sides– Decreases scatter dramatically

• Die attach using DAF – 10um thickness available

• Interconnect– Metal patterning– Bump (Bump after thinning)


www.cpmt.org/scv


[email protected]

47

THANK YOU!!Finn WilhelmsenRobert Corrao Dan Miranda

Precision Wafer Thinning and Dicing GroupCORWIL Technology.

Ron KoeppIMPINJ

Thinning of IC chips - IEEEewh.ieee.org/soc/cpmt/presentations/cpmt1001b.pdf · Thinning of IC...

Documents

Transcript of Thinning of IC chips - IEEEewh.ieee.org/soc/cpmt/presentations/cpmt1001b.pdf · Thinning of IC...