Proposal for Adopting Thermoset Resin to Enable Joint...

Proposal for Adopting Thermoset Resin to Enable 『Joint

Protection Flux & Paste』 Overcome Fine Pitch, Low

Temperature Assembly Issues Plus Reliability Reinforcement

Lewis HuangSENJU ELECTRONIC (TAIWAN) CO.,LTDVice President

2017 SEMICON SiP Summit –

Embedded and Fan Out Package

Technology Forum

Senju Metal Industry Co., 2017 SEMICON

Contents

Development Background

Packaging Roadmap vs. SMIC R&D Direction

Application of Epoxy Flux & Paste

Summary

Appendix


Development Background

Weak Heat-Resistance Parts

Smart phone, imaging sensors

Energy and Cost Saving

CO2 reduction

Automotive TCT Reliability Requirement

AEC Q100 (IC), Q200 Require

Fine Pitch Trend

Move to pitch 120um, 90um. Gap 50, 30 um

Package Warpage by Heat Effect

NOW, HIP, Shorting, Stretched joint


Source : Internet

http://www.google.co.jp/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjj65nI8KPVAhUhrlQKHSz6D9oQjRwIBw&url=http://sinap.jp/blog/2015/11/iot.html&psig=AFQjCNEzQH9iz_xQ0RQzxbqVCkA_331BeQ&ust=1501053018277152

http://www.google.co.jp/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjj65nI8KPVAhUhrlQKHSz6D9oQjRwIBw&url=http://sinap.jp/blog/2015/11/iot.html&psig=AFQjCNEzQH9iz_xQ0RQzxbqVCkA_331BeQ&ust=1501053018277152

http://www.google.co.jp/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj587yI8qPVAhVCy1QKHUErDVEQjRwIBw&url=http://www.geocities.jp/kj2bank/reflowwarpage.htm&psig=AFQjCNEM3FsX8gZWwy9TipgsT1Pq_JYxhg&ust=1501053358535687

http://www.google.co.jp/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj587yI8qPVAhVCy1QKHUErDVEQjRwIBw&url=http://www.geocities.jp/kj2bank/reflowwarpage.htm&psig=AFQjCNEM3FsX8gZWwy9TipgsT1Pq_JYxhg&ust=1501053358535687

Packaging Roadmap vs. R&D Direction

Source : SBR technology


Application of Epoxy Flux & Thermoset Paste

Epoxy Flux

For Ball Attach

Flux

residue

Thermoset Paste

For Embedded & SMT Flux

residue Solder

bump

Epoxy Flux

For Chip Attach

Die

Flux

residue

Each material can be selected by application.


Epoxy Flux

JOINT PROTECT FLUX

SMIC JPF

Key Features:

# Fine Pitch

# Reliability Reinforcement

# Epoxy Flux

# Thermoset Resin

# Joint Protection

# No Clean

# Cost Reduction


Roadmap of Epoxy Flux (Chip Attach)

2016 2017 2018 2019Year

Reducing

Flux cleaning Water No cleaning

Flux & Underfill

Combination

Become narrow

Water Water + chemical No cleaning

Water + chemical

Flux cleaning

Joint Protect Flux

(SMIC Epoxy Flux)

Without Underfill

< Pitch /Gap / Die &Die space >

< Process Cost >

WS flux

& CUF and/or MUF

150 120 100

80 50 30

< Pitch(μm) >

< Gap(μm) >

NC (No clean) Flux

& CUF and/or MUF


Concept of Epoxy Flux (Chip Attach)

Normal flux Process

Flux dipping & Mounting Reflow Cleaning Baking Underfill flow Cure

Finish

150um pitch150um pitch

Flux ResidueUF

Flux

Residue


Chip Attach Epoxy Flux (Present and Future)

～At Present Market ～

Die size □1~3mm □5~8mm □10~12mm □15mm over

Flux typeEpoxy flux

No clean flux

Water-soluble flux

Epoxy flux

No clean flux

Water-soluble flux

No clean flux

Water-soluble flux

No clean flux

Water-soluble flux

Flux residue of SMIC JPF becomes “Thermosetting Resin”.

Therefore, it reinforces solder joint and has good performance for strength

and reliability!

150um pitch150um pitch

SMIC

JPF

Epoxy flux is considered for small die & low cost model application.

Next

Generation

Epoxy Flux(Under development)

Junction reinforced

Half filling

Full filling


Next Generation Epoxy Flux (Reflow & TCB)

TCB

Full filling with filler

2016 2017 2018 2019

TCB epoxy flux

Die

siz

e [m

m]

Bump pitch [μm]

5x5

10x10

20x20

Reflowable

epoxy flux

150 120 80 60 40

Reflowable

Junction reinforced Half filling Full filling

Reinforced

shape

✓Void

✓Chip shift

✓ Warpage

Reflowable & TCBFlux

property

✓High wettability

✓High heat-resistance

Trade Off Relationship

When die size become bigger, or bump pitch become finer,

out gas is difficult to escape. And chip shift become easy to

occur. Therefore, TCB mounting is indispensable.

Reflowable

Epoxy flux

TCB

Epoxy flux

Advantage Disadvantages

High mass productivity

Low cost

Low mass productivity

High cost

Chip shift

Warpage

No chip shift

No warpage


Concept Epoxy Flux (WLP Ball Attach)

Normal flux Process

Flux supply Ball mounting reflow Cleaning & Baking

Finish

Flux residue Joint reinforced

You can reduce a cleaning process by using SMIC JPF.

And the residue of SMIC JPF can reinforce solder junction.

Joint protect flux


Mechanical StrengthBall Shear Strength

◇Test Condition

Flux typeSMIC JPF

Water-soluble flux

Solder alloy SAC305

Ball diameter 0.3mm

Substrate Cu-OSP coupon

SRO 0.24mm

Stencil

thickness/aperture0.1mm/0.24mm

Test speed 300μm/sec

Test height 15μm

Reflow times 1, 3, 6

Reflow profile25-250C 0.5C/sec,

250C peak

Fracture mode Mode 2 : solder

Even if increased reflow times, shear strength

of SMIC JPF is higher than Water-soluble flux.

＊WF-6317 is general water soluble flux. WF-6317 coupons clean for water after reflow.

Strength increase


Drop Test

After 135 times After 305 times

SMIC JPFOnly Solder Joint

After 16 times

Crack Crack Crack

Crack

196

9

Mean Std Dev Number

SMIC JPF 196.10 87.96 10

Only solder joint 9.90 5.74 10

Improved solder joint strength.

20

times!

Electrode

Solder

Electrode Electrode

Electrode


Solder Wettability

Wettability of SMIC JPF is better than conventional

and almost the same as water-soluble flux!


Insulation ReliabilityCondition

Environment：85℃/85%RH

Measured voltage ： 100V

Applied voltage ： 50V

Time ： 1000h

Since the ion migration does not occur and keep stable.

The insulation reliability is good.


TGA

Since weight loss is about 8% after reflow. (Almost no change.)

SMIC JPF can reinforce the solder joint with enough flux quantity.

8%


Thermoset Paste

JOINT PROTECT PASTE

SMIC JPP

Key Features:

# Low Temperature


# Thermoset Resin

# Joint Protection


Low Temp. Process Issues

Crack from bulk

The hardness and brittleness of Sn-Bi solder has poor 『Impact resistance characteristic』

Have to develop a product doesn’t crack when fall and even if

the stress happened won’t be damaged during assembly.


Flux Compose from JPP

Joint Protect PasteConventional Solder Paste

Electronic & Mechanical Joint

Spread Effect

Metal Deoxidize Effect

Self-Alignment

Alloy Function

Flux Function

Alloy Function

Electronic & Mechanical Joint

Flux Function

Reinforcement on

Solder Joint

Reinforced the solder joint strength by “Flux Residue”.

The Approach From Flux Materials

Spread Effect

Metal Deoxidize Effect

Self-Alignment


Reinforcement from Flux Residue

◆ BGA

◆ Chip

Chip

Due to flux residue became “Thermoset Resin”, reinforces solder joint.

Solder FLUX

Protect Joint by Flux Residue

FLUX

PCB

Solder

PCB

FLUX

BGA

Joint Protect Paste（JPP)


Drop Test Results (LGA Package)

Thermoset Resin Leads to Improve Drop Reliability

Due to “Thermoset Resin Protection”, JPP has significant increased on drop reliability, compares to other rosin type paste.


Joint Strength after TCT

Shear Strength (3216 Chip) Shear Strength (2012 Chip)

Due to “Thermoset Resin Protection”, JPP has significant increased on TCT reliability, compares to other rosin type paste.

TCT Condition : -40℃⇔ 130℃ / 30mins


Drop Test Results (Board Level)


Joint Protect Paste Issues and Solutions

Storage Instability１

２ Big Void


1) Storage Instability

• Competitors’ hardener in epoxy paste activates

SnBi Solder

Activator

Hardener

Epoxy

Storage

Continuous

printing

Increased

Viscosity

Continuous

Printing

Storage

• Senju developed a non-reactive hardener

No

Change

SnBi Solder

Activator

Hardener

Epoxy

SMIC JPP could be kept in refrigerator condition.


2) Void Occur Mechanism

Start melting During melting After cooling

Conventio

nal

paste

JP

P

Shrink

Expand

Expand Harden

The big void occurred in JPP due to harden, didn’t shrink.


Void Solution

Assembly

TechnologiesPaste develop

Leading-in market

Performance

Powder develop Equipment developSMIC Total Solution

・ Related to smart phone

・ Image sensor

・ Inside component assembly

・ Related to Communication

Analysis, evaluation

Technologies


Void Solution

Imp

roved

Overflo

w

During heating During cooling

Co

nv

en

tion

al

JP

P

Imp

rov

ed

JP

P

Resin harden

Solder

solidification

Resin harden

Solder

solidification

Point : During solder melting, resin could not get harden.

Start melting During melting After cooling

Co

nv

en

tion

al

JP

P

Imp

rov

ed

JP

P

Imp

roved

vo

id

Shrink

Expand Harden

Expand

Point : Develop the new flux which could shrink the void.


Summary

Key features of SMIC JPF ~

# Fine Pitch


# Epoxy Flux

# Thermoset Resin

# Joint Protection

# No Clean

# Cost Reduction

Key features SMIC JPP ~

# Low Temperature


# Thermoset Resin

# Joint Protection

A Soldering Partner You Can Rely On ~ SMIC.


Thanks For Your Attention!!!


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