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High Performances PPR Cu Plating for HAR Boards 高性能脉冲电镀铜及其在高纵横比线路板上的应用 Interconnect Technologies Dow Electronic Materials May 2016

Outline

Introduction Multilayer board trend Comparison of DC and PPR plating

Next Generation of PPR product —COPPER GLEAMTM PPR-II Acid Copper The capability on throwing power Bath stability & maintenance Reliability

Customer’s installation / Sample plating Application on the hoist line Application on the VCP line

Summary

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Trend of multilayer boards The increasing circuit density The increased board thickness/layer counts (10mm/56 layer or above) and reduced through hole diameter

(0.2-0.5 mm), thus the aspect ratio (AR) will reach 25:1 or above.

The increasing complexity of multilayer boards The mixed technology boards with any or all of through holes, blind vias, imaged patterns

The higher requirement of reliability

* Source: Prismark, Q2 2015

PCB Board Application

Multilayer

4 Layer 6 Layer 8-16 Layer 18+ Layers Americas -1.5% -0.4% 1.5% 1.6% Europe -1.9% -1.0% 4.6% 1.0% Japan -10.4% -9.3% -8.4% -7.1% China 5.5% 6.8% 7.2% 8.6%

Asia(xJpnxChn) 3.8% 3.9% 3.9% 6.1%

Total 4.9% 5.6% 5.1% 4.6%

2014 – 2019 Compounded Average Annual Growth Rate

Multilayer boards trend

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Comparison of DC & PPR plating

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Plating Mode Advantages Disadvantages

Direct Current (DC)

• Easy to control and maintain;

• Low cost of rectifier; • Stable bath performance; • Simple and commonly-used

technology

• Low current density/low efficiency

• Limited throwing power for HAR boards

Periodic Pulse Reverse (PPR)

• High throwing power (TP); • High current density/high

efficiency • Reliability; • Surface distribution;

• Hard to control and maintain; • High cost of rectifier

14~20 ASF 10~12 ASF 4~8 ASF

20~25 ASF 15~18 ASF 10~15 ASF

DC plating

PPR plating

Current Density

2 4 10 mm Board Thickness

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Next Generation of PPR product — COPPER GLEAMTM PPR-II Acid Copper

COPPER GLEAMTM PPR-II Acid Copper Process flow & Bath concentrations

Flow Chemistry Conc. Temp. 溫度 Time

Acid Cleaner Ronaclean LP200 Conc 50 mL/L

40 oC 5 min H2SO4 50% 130 mL/L

Micro-etch NaPS 70 g/L

RT 10 sec. H2SO4 50% 75 mL/L

Pre-dip H2SO4 50% 130 mL/L RT 1 min

Copper Plating

CuSO4 75 g/L

25-28°C

H2SO4 240 g/L

Cl ion 60 ppm

Copper Gleam PPR-II XC 15 mL/L

Copper Gleam PPR-II XB 2 mL/L

Copper Gleam Stabilizer Sol 3 mL/L

Copper Gleam R 0.4 mL/L

Anti-tarnish Cuprotec 10 mL/L RT 10 sec

• All inorganic components can be monitored by the wet titration • All organic components can be analyzed by CVS

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COPPER GLEAMTM PPR-II Acid Copper The capability on throwing power

(a)

(b)

(c)

(d) (e)

No. Boards AR Waveform (F/R)

Hole TP, %

Knee TP, %

(a) 3.2mmt/ 0.25mmФ 12.8 25/75 ASF

50/2 ms 124 90

(b) 4.0mmt/ 0.2mmФ 20 25/75 ASF

60/3 ms 98 91

(c) 4.8mmt/ 0.3mmФ 16 25/75 ASF

60/3 ms 97 85

(d) 8.0mmt/ 0.5mmФ 16 20/60 ASF

100/5 ms 113 125

(e) 5.5 mmt/ 0.25mmФ 22 20/60 ASF

100/5 ms 96 90

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Customer panel

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20/60 ASF 25/75 ASF

TP=98% TP=80%

COPPER GLEAMTM PPR-II Acid Copper Mixed technology boards—via plating & pattern plating

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Small via; 15/45ASF

Big via, 200 µm t x 250 µmФ, AR: 0.75

Section view

L/S: 2 mil

Top view

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COPPER GLEAMTM PPR-II Acid Copper High current density

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25 ASF 30 ASF 35 ASF 25 ASF 30 ASF 35 ASF

Hole TP Hole thickness

• Current density is as high as 35 ASF, using soluble anode • Has potential to use in high speed plating application

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COPPER GLEAMTM PPR-II Acid Copper Bath stability

3.2mmt/0.25mmФ

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Ref. Hole TP 100%

8.0mmt/0.5mmФ

• Excellent and stable TP in the tested bath life of ~250 AH/L (Mar 2015-now, work normally for over 13 months, ~300 AH/L) • No needs for continuous carbon polish or carbon treatment during the tested period

25/75 ASF 20/60 ASF

Ref. Hole TP 100%

Ref. Hole TP 100%

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COPPER GLEAMTM PPR-II Acid Copper Bath maintenance

• Available for CVS analysis • PPR-II can endure 2 days, and even 13 days idling without TP% dropping • Easy to restart without a dummy process

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8.0mmt/0.5mmФ Idling test conditions Bath life @ ~200 AH/L Idling for 2 and 13 days with Cu anode without air agitation

Restart Process All bath components were adjusted to the normal range by the replenishment, and then directly plate 8.0 mm boards without the dummy process

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COPPER GLEAMTM PPR-II Acid Copper Physical properties

AH/L 0 50 100 160 200

Elongation, % 28.7 32.7 30.7 33.0 33.3

Tensile strength, kpsi 45.2 43.0 43.7 41.5 44.8

• The consistency of elongation and tensile stress in the bath life from 0 to 200 AH/L

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COPPER GLEAMTM PPR-II Acid Copper Reliability

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Test Result Method

Thermal reliability

•Pass 9 cycles of solder floats at 288 oC, 10 seconds

IPC-TM-650, method 2.6.8 V. E

Reflow test

•Pass 10 cycles of lead-free soldering reflow with peak temp. at 245 oC; •Max. resistance change < 5%

IPC/JEDEC J-STD-020C

Thermal shock test (TST)

•Pass 500 cycles (Requirement 100 cycles, internal target: 500 cycles); Liquid to liquid, -55oC ~ 125oC; •Max. resistance change < 4%

IPC-TM-650, 2.6.7, condition D

Interconnect stress test (IST)

•Pass 1000 cycles of IST test from RT to 150oC; •Max. resistance change: 1.4%

IPC-TM-650, 2.6.26

After test

Reflow unit

Hole center Corner

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Customer’s installation / Sample plating

Application on the hoist line—Customer U TP performance

• 3.7 mm board: pattern plating • Minimum hole TP: Dow > competitor

0 20 40 60 80

100 120 140 160

Ø0.25 Ø0.30 Ø0.35 Ø0.75 Ø1.00

Minimum Hole TP %

Dow 20ASF, 1:2, 30:1ms Competitor 20ASF, 1:3, 30:1ms

0

20

40

60

80

100

120

Ø0.25 Ø0.30 Ø0.35 Ø0.75 Ø1.00

Ave. Knee TP %

Dow 20ASF, 1:2, 30:1ms Competitor 20ASF, 1:3, 30:1ms

0 20 40 60 80

100 120 140 160

Ø0.25 Ø0.30 Ø0.35 Ø0.75 Ø1.00

Ave. Hole TP % (6 points)

Dow 20ASF, 1:2, 30:1ms Competitor 20ASF, 1:3, 30:1ms

* Performed by the customer

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Application on the hoist line—Customer U Grain structure by OM & FIB

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Surface Corner Hole

3.7mmt/Ø0.25mm board Pattern plating Fine, equiaxed polycrystalline grain structure

Surface/Corner Hole

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Application on the hoist line—Customer U Reliability

Item Requirements Results OK?

Via Chain Thermal Stress

• 288oC/10sec/20cycle; • Resistance change < 5%

• 10x solder float, R change =0.57%; • 20x solder float, R change =1.06%; • No crack

Pass

Reflow + 4W Test

• Pb-free profile (260oC) /20cycle; • Resistance<2mΩ before & after reflow

• Resistance <2mΩ before & after reflow • No crack

Pass

Thermal Shock Test

• -55oC ~ 125oC; • Resistance change < 10%

• After 1024 cycles, Max. resistance change =2.78%

Pass

* Performed by the customer

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Application on the VCP pilot line—Supplier C

Pulse Rectifier

Circulation Pump

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Application on the VCP pilot line—Supplier C

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(1) Panel: 3.2 mmt panel / 0.25mm diameter (DOW), electroless Copper

25/50 ASF, 20/1 ms, 50 min

(2) Panel: 5.5 mmt panel / 0.4mm diameter (from customer), flash Copper

20/60 ASF, 60/3 ms, 100 min

Hole TP: 125% Knee TP: 89%

Hole TP%= 121% Knee TP% = 98%

Pass 9 cycles of solder float test @ 288 oC, 10 seconds

Hole TP: 114% Knee TP: 95% Hole TP: 114% Knee TP: 95%

(3) Panel: 8.0 mmt panel / 0.5mm diameter (DOW), electroless Copper

20/60 ASF, 50/2 ms, 120 min

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Summary

COPPER GLEAMTM PPR II Acid Copper is specially designed for plating through hole in high aspect ratio boards, working with soluble anodes and simple waveform in vertical application. It offers the following features:

Performance Stable and high TP (~100%) performances for a various of board thicknesses and hole diameters

in the tested bath life of ~300 AH/L, plating for over 13 months Good thermal reliability and physical properties , pass solder float test, reflow test, IST and TST Capable of panel, pattern and via Plating processes

Operation & Maintenance Available for CVS analysis No needs for a continuous carbon polish or frequent carbon treatments during operation in

the tested bath life of ~300 AH/L Easy to restart with good TP even after 13 days idling without a dummy process

Compatible with both hoist and VCP lines

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Thank You