European 3D TSV Summit 2015

Progress in TSV

Stacking Using

TCB Process

Dr. Hugo Pristauz

VP Thermocompression Bonding & Die Sorting

Solder Flip Chip Evolution

European 3D TSV Summit 2015

10µ@3

Mass Reflow Flip Chip Processes

*) C4: Controlled Collapse Chip Connect (IBM)

**) C2: Chip Connect (IBM)

TC Flip Chip ultra fine pitch ≤40µ

Flip Chip on LF coarse pitch ≥ 200µ

C2 Flip Chip **) fine pitch ≥ 50µ

Cu-pillar

Flip Chip C4 Flip Chip *)

standard pitch ≥ 130µ

low

Productivity

local reflow

mass reflow

high

Productivity

Jan-2015 2

Jan-2015

TSV Stacking – High Volume Production

3 European 3D TSV Summit 2015

Current Driver: HMC

TC-Bonding

is Key to

TSV Stacking

TC-NCP Process (pre-applied nonconductive paste)

TC-CUF Process (capillary underfill,

or TC-MUF: molded underfill)

TC-NCF Process (WL applied nonconductive film,

or TC-WLU: wafer level underfill)

Jan-2015

TC Bonding Processes

5 European 3D TSV Summit 2015

T F

T F

T F

Oct-2014

• Thermo compression bonder

• +200/-100 °C temperature

ramping

• 2µ @ 3 sigma accuracy

• 250 N bond force

• C2S / C2W

• TC/NCP, TC/NCF, TC/CUF

Datacon 8800 TC Thermo Compression Bonder

6 Confidential

8800 TC

Launch: March 2014

Now 12 x 8800 TC installed base

Preparing for 5 bonder / month shipment

Jan-2015

TCB Bonding

7 European 3D TSV Summit 2015

Challenges in

TCB / TSV

HV Production

Jan-2015

Challenge Level of TSV Stacks

9 European 3D TSV Summit 2015

4-Stack HMC 1+4 HMC 1+8

initial

estimation

of challenges

current

understanding

of challenges

challenge level

from a view

of TC bonding

Challenges:

1) High Capabilities

2) Tool2Tool Repeatability

3) Monitoring & Alarming

Jan-2015

Bond Control for CUF Process

10 European 3D TSV Summit 2015

z (position)

T (temperature)

F (force)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5-20

-10

0

10

20

30

40

50

-200

-100

0

100

200

300

400

500

Tem

pera

ture

[°C

]

Bond Control for CUF Process

Forc

e [

N],

Positio

n [

µm

]

time [s]

high temperature

ramping rate

200°C/s

dynamic

z-control

during collapse

thermal

compensation

rapid cooling

-100°C/s

• Challenge 1: How do you teach the position control?

• Challenge 2: How do you move from one tool to another?

T (temperature)

F (force)

z (position)

Capabilities

Oct-2014

High Capabilities

12 Confidential

8800 TC

7-axis

bond head

auto

tilt setupt

bond

control

(force/pos.)

dynamic

bond

control

2µ@3s

@

250 N

rapid

heater &

cooler

individual

bond profiles

per layer

temperature

sensing

In nozzle

Oct-2014

7-Axis / 250 N Bond Head

13 Confidential

x/y micro

actors

force

actuator

(high dynamics)

theta

axis

main

z-axis

• 2 x actuators for bond control • 2 x actuators for auto tilt setup

Jan-2015

Enhanced Bond Control for CUF Process

14 European 3D TSV Summit 2015

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5-20

-10

0

10

20

30

40

50

-200

-100

0

100

200

300

400

500

Tem

pera

ture

[°C

]

Enhanced Bond Control for CUF Process

Forc

e [

N],

Positio

n [

µm

]

time [s]

• By distributing bond control over two position axes

the complexity of the bond control is reduced

w (position)

T (temperature)

F (force)

z (position)

thermal

compensation

@ z-position-axis

w-position axis

used for

BLT control

Monitoring/Alarming

&

Tool-2-Tool

Repeatability

Jan-2015

• Setting up alarm windows for any process variable at chosen time

• Process variables are monitored against defined alarm windows

• Escaping an alarm window generates a machine stop and an alarm

Integrated Monitoring & Alarming

16 European 3D TSV Summit 2015

Jan-2015

Key for Recipe Portability & Time to Yield

• machine parameters & recipe parameters must be strictly separated

• auto calibration procedures ensure consistently calibrated tools

Key for Monitoring & Alarming

• Portable alarm-windows are only working on repeatable tools

Tool-2-Tool Repeatability

17 European 3D TSV Summit 2015

Jan-2015

• High repeatability due to sensor integration in bond tool

• Define a metrics which an automatic diagnostic can check

Thermal Repeatability

18 European 3D TSV Summit 2015

0 2 4 6 8 10 12 14 16 18-10

-5

0

5

10

15

20

25

30

35

Initial

3*sig = 0.05 °C

Cmk = 20.09

Warm-up

3*sig = 0.22 °C

Cmk = 4.5

Heating

3*sig = 0.35 °C

Cmk = 2.86

Cooling

3*sig = 0.59 °C

Cmk = 1.7

Residual Temperature Analysis: std = 0.12 °C, Cm = 2.86@+/-1°C (during heating)

$1 WH1 @ #2.42 (11:37)

-100

-50

0

50

100

150

200

250

300

350

0 0.5 1 1.5 2 2.5 3 3.5 4-10

0

10

20

30

40

50

-100

0

100

200

300

400

500

Tem

pera

ture

[°C

]

Verification of Thermal Expansion Compensation

Forc

e [

N],

Positio

n [

µm

]

time [s]

Jan-2015

• Thermal expansion is automatically identified

• z-axis performs (feed-forward) thermal compensation movements

• Metrics for proper compensation: w-axis has to stay within +/- 1µ

Compensation Repeatability

19 European 3D TSV Summit 2015

w (position)

z (position)

T (temperature)

F (force)

• TSV/TCB stacking is now in HV production, driven by

memory cube business

• 3 factors are crucial for TCB HV production: capabilities,

tool-2-tool repeatability and monitoring&alarming

• Reduction of complexity of the bond control can be

achieved by dual z-axis control, where the first one is

running thermal compensation, the other one does force

or bond line control

• Thermal repeatability leverages from sensor integration

in the bond tool

• Usage of proper metrics is helpful to verify Tool-2-Tool

repeatability (e.g. thermal-repeatability, compensation

repeatability)

• Integrated monitoring & alarming is mandatory for HV

TCB bonding. Tool-2-tool repeatability is mandatory for

integrated monitoring & alarming

Summary