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CircupositTM 6500 process: Next Generation Horizontal Electroless Copper Process with Ionic Catalyst System for ELIC and IC Substrate Application

新一代水平化铜工艺的应用

Contents

1. Market Outlook

2. ELIC and IC substrate PCB Technology Requirement

3. Introduction of CircupositTM 6500 process

4. Bath Stability of CP6530 & CP6550

5. Plating performance

6. Copper grain structure and boundary study

7. CircupositTM 6500 performance of IC substrate PCB

8. Highlights

9. Q & A

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Market Outlook

Global PCB market trend towards advanced technology boards with excellent reliability requirement (High-density-interconnect(HDI), Integrated Circuit packaging substrate(IC substrate), Flex and Rigid Flex).

3

Global PCB Product Mix, YR 2000 (L) vs YR 2014 (R) (Source: Prismark)

Multi-layer

boards45%

HDI17%

IC PKG15%

Flex/RF23%

Multi-layer

boards77%

HDI5%

IC PKG8%

Flex/RF10%

Technology Requirements

High Density Interconnect (HDI) is a technology of using small form factor in complex electronic circuit designs. Everylayer interconnection(ELIC) is a compact design using viafill technology. High reliability and excellent coverage is needed.

4

Vias: ~75-100um dia

Through holes: ~100-300um dia

SEM Photo of Via:

Important reliability

of this electroless

copper layer

https://www.protoexpress.com/hdi/hdi-for-semiconductor

www.apple.com.hk , www.samsung.com.hk

www.ifixit.com

https://en.wikipedia.org/wiki/HDI

Modified Semi Additive Process (MSAP)半加成法

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A modified SAP process, also referred to as Advanced-Pattern Process, is often used in HDI fabrication. In this case, a laminate coated with a thin copper foil is used for the starting material, rather than a bare dielectric.*

*Quoted from: Next Generation Electroplating Technology for High Planarity, Minimum Surface Deposition Microvia

Filling , Dow Electronic Materials, The Dow Chemical Company

IC Substrate PCB Application

MSAP introduces to IC substrate PCB application for achieving line/space lower than 40/40um. In Electroless Copper, extra requirements in:-

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High Electroless Copper Thickness in Via Bottom

- >200nm-300nm in Via Bottom

Compatible to patterning steps in MSAP process

7

• Customer std processDesmear

• CIRCUPOSITTM 3323A or 233

Conditioner

•NaPS microetchMicroetch

• CIRCUPOSITTM 6520 Predip

Predip

• CIRCUPOSITTM 6530 Catalyst

Catalyst

• CIRCUPOSITTM 6540 Reducer

Reducer

• CIRCUPOSITTM 6550 Electroless Copper

Els Cu

Key Chemicals Control Parameters

CIRCUPOSITTM 6530 Catalyst

Pd: 200 ppm; pH 9.0 – 9.5

CIRCUPOSITTM 6550 Electroless Copper

1) Cu 2.5 g/L2) Rochelle salt3) NaOH4) HCHO5) Stabilizer 6) SG =1.04-1.09

Introduction of Dow Ionic Catalyst Process - CircupositTM 6500 Process

Bath Stability of Circuposit 6530 Ionic Catalyst Bath

&Circuposit 6550 Electroless Copper Bath

8

Bath Life of Circuposit 6530 Ionic Catalyst Bath

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Long Catalyst Bath Life - Greater than 1 Month

Catalyst Items Starting Aging 22h Aging 44h Aging 68h Aging 192h

DowTurbidity /NTU 0.2 2.9 4.9 7.1 9.8

[Pd] /ppm 198 198 204 200 210

CompetitionTurbidity /NTU 0.4 4.0 10.0 17.1 47.0

[Pd] /ppm 197 206 196 201 195

0

50

100

150

200

250

0

15

30

45

60

75

0 22 44 68 192

Turb

idit

y (N

TU)

Aging time (hr)

Catalyst stability comparison

Turbidity _Dow

Turbidity_Comp

[Pd] _Dow

[Pd]_Comp

[Pd]

(pp

m)

Aging condition: 40 oC heating with strong agitation.

10

Stability test of CP6530 Ionic Catalyst Bath

Stability Test of Circuposit 6530 Ionic Catalyst Bath

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Competitor DOW

Status Starting.After 192

hours (8 days)

Starting.After 192

hours (8 days)

Filter paper

This test showed higher stability of catalyst will have less sludge contain in catalyst bath. This will have less catalyst consume in filter chamber and lower risk for the sludge stick on the panels.

Competition CP6530

After 192 hours (8 days)

Catalyst Filter in filter chamber.

Electroless Copper Bath life

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Stable tartrate-based e’less Cu bath.No plate out after 1 week production (SG=1.090)

Plate Out of generic tartrate

High Stability of CP 6550

Simulated Stability Test43 ˚C Bath Temperature without air agitationKeep 48hr without any plate out for CP6550

Piping in sump tank

Filter Chamber

Plating Performances

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ICDNo break between

innerlayer, e’less and EP Cu

HCT Pin-PullNo break between via pad

and e’less Cu

Peel Strength

Backlight CoverageDegree of e’less Cu

coverage in through-hole and via

Electroless Plated Coupons

Electrolytic Plated Coupons

Electroplating

Mode

1

Mode

2Mode 3

No break between via pad and e’less Cu

MorphologySmoothness of the e’less Cu deposit

SubstrateCu film

Adhesion of plated Cufilm to the smooth substrate surface

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Plating Performance Evaluation

Plating Coverage In Different Kinds of Laminates

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IT158 IT180 370HR TUC662 NPGN S1141

Excellent coverage on glass and resin

Backlight Performances in One Month Catalyst Bath Life

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Backlight grading are larger than >4.5, out of 5 throughout Catalyst Bath life

PinPull Test (盲孔底拉斷測試)

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PTH & 25um EP Cu

• 125 ˚C for 6 hoursBake

• ɸ3mm2 tape mask

• 12min fresh 10% H2SO4 + 3.5 % H2O2

Etch

• 125 ̊C for 2 hoursBake

• 5X 10s float @ 288 ̊CSolder Float

• Using tensile elongation tester to pull the pin

Pin Pull

Mid-Via break

Interface break

Pad break

Source from Reliability Test Methods for Copper Plated Filled Microvia by Motorola

Pass PassFail

PinPull Test (盲孔底拉斷測試)

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Pin-pull monitoring result

Pinpull test has 100% pass rate

High Current Test (HCT) Result (高電流測試)

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Circuit break time requirement is >60 seconds.

Testing Criteria:

• First 30 sec., Temp.≧140 C;

• Next 30 sec., 180 C ≦Temp.≦ 240 C

Applying constant current: 2.3A, 11V max.

(Current may be changed depending on the design of a coupon)

High Current Test (HCT) Result (高電流測試)

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HCT tests are passed.

Day of Catalyst HCT pass time

Day 03 >60 sec

Day 04 >60 sec

Day 13 >60 sec

Day 15 >60 sec

Day 30 >60 sec

Throwing Power of Electroless Copper (Through hole)

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Throwing power of through holes is ~100%

210um320um

Throwing Power of Electroless Copper (Blind Via)

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Throwing power of blind via is 70-80%. (Ni-free)

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Thickness (nm) Left Right

Top 109 ± 16 111 ± 15

Middle 105 ± 13 105 ± 2

Bottom 99 ± 12 80 ± 10

Sampling area for thickness measurement

Ø 85 um42 um

Other HDI Reliability Tests

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Reliability tests are all passed.

Test Requirements Result

HDI

Hot oil shock test(260 ̊C x 10 sec -> IPA dipping 20 ̊C x 10 sec)x10 cycles

All Pass1) No copper plating void2) No barrel and foil crack3) No separation on

through hole

Thermal shock cycle test(-55 ̊C x 15 min <-> 125 ̊C x 15 min) x 100 cycles

IR reflow test (240 peak x 5 cycles)

Copper grain structure and boundary study

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Electroless Copper Grain Structure

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Circuposit TM 6500

Overall Resin

Via Pad Morphology

Even coverage and good grain structure

Copper to Copper Grain Boundary

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Interface Study by EBSD

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Electroless

copper

interface

FIB/SEM Analysis of Copper to Copper Grain Boundary

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No demarcation line observed.

CircupositTM 6500 Performance in IC substrate PCB

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Morphology of Deposited Copper On IC Substrate PCB Blind Via

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Smooth morphology in hole wall and via bottom

f 125 mm

42mm

Line Speed (eCu dwell time)

1.0m/min (8.7min)

0.8m/min(11min)

0.6m/min (14.5min)

Thickness (nm) Left Right Left Right Left Right

Top 550 ± 74 530 ± 30 740 ± 60 810 ± 112 910 ± 42 825 ± 90

Bottom 205 ± 16 221 ± 24 320 ± 40 221 ± 24 465 ± 146 389 ± 14

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Electroless Copper Bath containing Nickel (typically 150 - 200 ppm) was used

Via Bottom Electroless Copper Thickness

Other IC Substrate Board Reliability Tests

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Reliability tests are all passed.

Test Requirements Result

IC Substrate

PCT test (121 ̊C x100%x2 atm) -> 96hrs Pass

Thermal shock cycle test(-55 ̊C x 15 min <-> 125 ̊C x 15 min ->500 cycles)

Pass

HAST test (85 ̊C x 85% -> 168 hrs) Pass

Highlights of CircupositTM 6500 Process

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High Performance in blind via reliability

- Strong interconnect of electroless copper between target pad and EP copperc

Excellent Coverage

- Excellent Coverage in different kinds of laminates

Cost Effective

– High stability of ionic palladium catalyst bath

Sustainable

– High stability of electroless copper by using EDTA free and Cyanide free chemistry

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ThankYou