K&S Thin Die Technology - SEMATECH

K&S Thin Die Technology Sematech Symposium Hsinchu October 2012

Thin Die Technology – Agenda  Introduction  Beneficial Machine Architecture  Pick Process & Process Control  Application Tools and Optimization Process  SW Features for High End Apps  Yield Assurance  Conclusion / Roadmap

Die & Film Thickness Trends Indexerfor Thin Die Handling Technology: Key Driver

Film over Wire

Production (high end MCP)

Mother Die DAF

Qualification / Demo

Daughter Die DAF

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Successfully Processed Thin Die App’s on iStack

3 Layer Stack (MD – DD – Controller) Thickness 15mm Die / 5mm DAF

Successful iStack Thin Die Applications 20

Qualification / Production Piston Ejector Demo Slider Ejector Demo

10 Layer Shingle Stack Thickness 15mm Die / 5mm DAF

Die Size [mm]

15

10

5

0 10

20

30

40

50

60

70

Die Thickness [µm]

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4

80

90

100

110

K&S Thin Die Technology Overview

 Thin Die (Needle-less) Ejector & Pick Mode  Dedicated Vacuum Supply  Special ‘Seal Lip’ Tool  Multi-Step  Smooth Tool Lift-off  Expert Diagnostics  Step-wise Pick

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Die Size [mm]

20

15

10

5

0

100 90

Standard & Multi Needle (Magnetic) Die Ejector Confidential

80

70

60 50 40 Die Thickness [µm]

30

Thin & Small Die (Needle-less) Ejector & Pick Mode 5

20

10

K&S Thin Die Pick Technology - Machine Architecture

Equipment Architecture Moving Bond Vision Fixed Transfer Vision

Key Benefits for Thin Die Handling:  Process Performance & Flexibility  Optimized pick & place tooling design

 Highest Throughput  Long pick times for high-end DAF/FOW app‘s are „hidden“ behind bond process through parallel die handling

Indexer Fixed Pick Vision

 Process Stability  „Cold“ pick process while bonding @ high temperatures Die Ejector

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Equipment Architecture = Process Flexibility  Pick Tool – Many big holes = Strong pick

 Multi-hole tools optimized for pick yield

Separated PTP architecture allows for optimized pick & place processes!

 Transfer Tool – High Accuracy

 Transfer tool designed for highly accurate handover process  Vacuum holes location optimized to prevent “potato chip effect” on thin die for reliable vision Tool has “self cleaning” effect and lowest surface energy – optimized for WBL/FOW handling

 Place Tool – No Voids  Tool optimized to eliminates voiding

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K&S Thin Die Technology – Pick Process & Process Control

Thin Die Picking Method Piston Ejector 1. Tool Impact Vacuum Level Impact Speed Pick Force

2. Initial Peeling Separation Distance Separation Speed Multi-Step Separation configurable

3. Retraction – Final Peeling

4. Die Pick-up

Pick Force Retract Distance Retract Speed Multi-Step Retraction configurable

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Smooth Tool Lift-off configurable

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Thin Die Picking Method Slider Ejector 1. Tool Impact

2. Initial Peeling

Vacuum Level Impact Speed Pick Force

Eject Height Eject Speed Slider Speed Slide Distance Multi Step configurable

3. Final Peeling Sliding Distance Slide Speed Multi Step configurable

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4. Die Pick-up Smooth Tool Lift-off configurable

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(Thin) Die Handling Process Control Transfer Force Repeatability at 0.8N Over 1 Hour Production at 4500 UPH

iStack’s Tool Impact, Force & Position Control for Minimum Stress on the Die:  Tool impacts at user adjustable constant velocity  Tool impacts are automatically detected and adjusted during each machine cycle



0.1 0 -0.1

s = 0.008N, Range = ±0.03N

-0.2 -0.3

Force Control:

0

 Force is generated by linear motors (spring-less) with auto calibrated current loops  Highest force repeatability through closed loop current control



Deviation from 0.8N

Tool Impact Control:

0.2

Position Control:  Dies are positioned and handed over between tools within 1.5µm (sigma), implying zero shear stress during pick and handover  Drifts are eliminated through “Dynamic Calibration” during production

600

1200

1800

12

3000

3600

Pick Arm Positioning Repeatability 5 4 3 2 1 0 -1 -2 -3 -4 -5 0

200sX  0.2µm, 400 sY600  0.4µm800 Cycle # Y

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2400

Time [s]

Position [µm]



0.3

X

1000

K&S Thin Die Technology – Application Tools and Optimization

Thin Die Ejector Optimization Die Ejector Design Optimization using Finite Element Analysis based on: 

minimizing tensile (center and neighbor) die stress near/along the die edges



maximizing peel stress along the die edges

Peel Stress FEA – Separation Step

Center Die

Neighbor Die

Die Stress FEA – Separation Step Center Die

Neighbor Die

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Thin Die FEA Model Validation Excellent agreement between FEA model and Pick Test (7.8x10.8mm Die, 25µm thin) FEA Model: Red WBL sticks on Tape, Blue WBL peeled from Tape

Ejection Height Low

Ejection Height Medium

Thru-Tape Photos: Dark Grey WBL sticks on Tape, Light Grey WBL peeled from Tape Confidential

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Ejection Height High

Thin Die FEA Model Validation

Die Thickness DAF Tape Die Sizes

100.00%

1800

99.00%

1600

98.00%

1400

97.00%

Yield

Pick Cycle time

15µm Hitachi FH9011 17.15mm x 9.70mm 16.90mm x 10.65mm 10.80mm x 7.80mm 350ms

1200

96.00% 1000 95.00% 94.00% 93.00%

"no crack" yield

800

pick yield

bonded units

600

92.00%

400

91.00%

200

90.00%

0 Piston 2011

ejector type Piston 2011 Piston 2012 Slider

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Units Bonded

Process Tests on Various Devices for Verification of FEA Results & Developments  Test Device Information: Thin Die Picking Performance on 15µm Die

die picked 224 231 1684

Piston 2012

crack yield 100.00% 100.00% 100.00%

Slider

pick yield 99.55% 100.00% 100.00%

total yield 99.55% 100.00% 100.00%

K&S Thin Die Pick Tools Seal Lip Pick Tool maintains vacuum between tool and thin die if the die deforms:  

Strengthens grip and adds stiffness to the die  Increases pick-up yield Avoids stress due to pressure difference between atmospheric pressure and ejector vacuum  Reduces die bending

Standard Pick Tool

Seal Lip Pick Tool

FEA of tool with vacuum, showing lip seal compliance

Flexible seal to cover the edges of die

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Thin Die Technology – SW Features for High-End App’s

SW Features for High-End App’s Multi-Step Separation Process: 

More flexibility to parametrize the separation process



Better control of initial peel process for applications with high “edge tackiness” (Fast) Initial peel process for low “edge tackiness”:

Configuration of Multi-Step Separation

Dt = 2ms

Pick Tool / Piston Position [µm]

Die in front

Pick tool

(Slow) Initial peel process for high “edge tackiness”: 250 200 150

Dt = 40ms

100 50

Dt = 60ms

0 0

100

200

300

400

500

600

700

Time [ms] Separation @ 1% Speed

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800

Dt = 70ms

With Multi-Step Separation

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SW Features for High-End App’s Smooth Pick Tool Lift-off @ End of Pick Process: 

More flexibility to parametrize the pick tool lift-off motion



Higher process reliability for extremely thin or high “edge tackiness” dies

Configuration of Smooth Lift-off

1

Pick tool

2

3

Die lost from tool

4

Pick Tool Position [µm]

100 80 60 40 20 0 0

50

100

150

200

250

300

350

400

Time [ms] Slow Setting

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Medium Setting

Fast Setting

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SW Features for High-End App’s K&S Mixed Signal Scope for Process Setup: 

K&S includes unique monitoring and diagnostics SW scope, tracking all  



axes position, speed & acceleration set points & actual readings, digital and analogue I/O’s

Allows for detailed pick process analysis & optimization

Example: Pick tool detects leaks between pick tool and die  Conclusions on effectiveness of peel process Pick Tool Flow Sensor & Vacuum Supply

Ejector Vacuum Supply

Initial peeling not started – leakage between tool and die during separation Confidential

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Pick Tool Flow Sensor & Vacuum Supply

Ejector Vacuum Supply

Initial peeling completed – no leakage between pick tool and die

Thin Die Technology – Yield Assurance

Yield Assurance Crack Inspection System Transfer Camera:

Hi-Resolution Microscope:

K&S technique:

 Full Die image @ 30µm/pix  Technically NOT possible to

  0.6µm/pixel  very small FOV  Hard to tell Edge from Cracks  Needs multi-image scanning

 Full Die image at 60µm/pixel resolution  Special illumination technique  High resolution NOT required even for 1µm crack

make Cracks visible with full field FOV sensor (MP limit)

(time consuming = low UPH) Cracks appear as bright signals on dark background

Red Lines indicate Cracks 10.0mm Confidential

320µm

17.1mm

1.7 / 4.4µm crack width

SEM image  10mm

210µm 23

“Crack Detection Module” Inspection after Die Pick-Up

Thin Die Technology – Conclusion / Roadmap

Conclusion / Roadmap Conclusion 

Production proven ‘Best in Class’ Thin Die Handling



Demonstrated Unique Crack Detection Capability

Roadmap - Extension of Current Thin Die Technology to Advanced Packages





Background 

TSVs will create different stress distribution in thin die.



Thinner Die  easier Via manufacturability  smaller possible Via  (aspect ratio Via depth/)



Pillars are not touchable. Changed Pickup Tool geometry  different stress distribution.

We will enhance existing technology for thinnest possible TSV / Copper Pillar Die. 

Verification on suitability of existing thin die technology is started



Reduce inner stress on TSV and Copper Pillar Dice with FEA models and validation.



Looking for partners to validate Technology on TSV and Copper Pillar Dice in production environment.

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Question

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Answers

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