IPC-4556 印制板化学镍钯浸金（ENEPIG）规范ENG - 第72页

IPC-4556-a8-4 Figure A8-4 (T op) Summary of 1 mil Gold Wire ENEPIG Destructive Pull T est (DPT) Results and (Lower) Comparison of X-Y Directional DPT V alues 4 2 6 8 10 12 De s tr u ctive P u ll V a l u e s (Gr a m s ) D…

1 mil Gold Wire Bonding and Destructive Pull Testing Evaluation per MIL-STD-883 The 1 mil gold wire bond parameters

developed for the ENEPIG plating ﬁnish test vehicles were based upon the same 1 mil gold wire bond approach used in the

development of the wire bond parameters designed for production level substrates with gold plating ﬁnish.

Manufacturing processes and operations are inherently speciﬁc. While automatic wire bonders are similar, they may be dif-

ferent in speciﬁc aspects. Wire bond ﬁxtures and capillaries are critical and play a signiﬁcant role in a successful wire bond-

ing operation. The experience levels of the wire bond operator are also important.

Following removal of the coupons from the panel and marking of the coupons, the parts were baked in a nitrogen oven at

150 °C [302 °F] for 4 hours. The parts were then plasma cleaned and wire bonded. 120 wires were placed onto each con-

ditioned coupon. A minimum of 10 each 1 mil gold wires per coupon in the X-direction and 10 wires in the Y-direction were

bonded, followed by DPT (see Figure A8-1).

The 1 mil gold wire bonding parameters selected for bonding on substrates with an electrolytic gold plating ﬁnish were

modiﬁed for the bonding of ENEPIG coupons with the immersion gold ﬁnish, as follows:

Reduction in Power by 7%

Force was increased by 10%

Time was increased by 100%

Stage temperature at the substrate surface was 150 °C±5°C[302 °F ± 9 °F].

MIL-STD 883 destructive pull test requirements for all ENEPIG test vehicles were met (see Figures A8-3 and A8-4).

Figure A8-3 Visual Evaluation of Wire Bonding Showing Classical Crescents Resulting in Neck Breaks

(Left) Destructive Pull Test value of 12.5 grams / (Right) DPT is 5.5 grams

January 2013 IPC-4556

Vac-High PC-Std. 10 kV

50 m

4/5/2011 *000055 VarcHigh Pc Srd.oky

20 pm

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IPC-4556-a8-4

Figure A8-4 (Top) Summary of 1 mil Gold Wire ENEPIG Destructive Pull Test (DPT) Results and (Lower) Comparison of X-Y

Directional DPT Values

Destructive Pull Values (Grams)

Data S

Plating Methodology: Wilrebond Direction

et #1

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et #40

Summary of NiPdAu Destructive Wire Bond Pull Tes

Data Set #41

Data Set #42

t for 1-MIL Gold Wire

I II-SN13-3 II-SN13-4 III-SN7-2 III-SN7-3 III-SN7-4

IVB IXB XXB

VA VIIA VIIIA XB

XIB

XIIA

XXIB XXII2-A XXIVA

Participants

Uyemura - Japan

Uyemura - US

XXR

XXVA

DOW

MacDermid

Cookson-Ethone

OMG

Atotech

Mil-STD 883 Requirement = 3 Grams

ENEPIG Plating Finish 1-mil Gold Wirebond Results X-Y Bond DPT Comparison

Min

Median

Max

IPC-4556 January 2013

Upon completion of the ﬁnal wire bonding and submission of data, the plating ﬁnish sample thicknesses were obtained and

summarized. The results are shown in Table A8-III.

SUMMARY

The tasks identiﬁed through consensus of the IPC 4-14 Plating Processes Subcommittee to evaluate the suitability of Elec-

troless Nickel Electroless Palladium Immersion Gold (ENEPIG) as a ﬁnish for gold ball wire bond bondability included

development of an industry Round Robin with roles and responsibilities, development of a wire bond test vehicle, partici-

pation of commercial ENEPIG plating ﬁnish suppliers, establishment of ENEPIG plating ﬁnish attributes to evaluate the wire

bonding and 1 mil gold ball wire bonding destructive pull testing evaluation per MIL-STD883.

The wire bond test vehicle artwork was supplied by Kulicke and Soffa, fabrication of the test vehicle was conducted by TTM

Technologies, Inc. and the ENEPIG plating ﬁnish was supplied by commercial suppliers, Uyemura, Dow Electronic Mate-

rials, MacDermid, Enthone-Cookson, OMG and Atotech.

The electroless palladium target thicknesses were 4, 8, 12 and 20 microinches. The nickel and immersion gold thicknesses

were not considered variables.

One set of 1 mil gold ball wire bond parameters were selected for testing all six (6) ENEPIG supplier ﬁnishes evaluated in

this study.

All destructive pull testing results for all 6 commercial ENEPIG plating ﬁnish suppliers were in compliance with MIL-STD-

883 requirements.

Table A8-III Summary of Plating Finish Thicknesses for Samples Wire Bonded

Summary of Plating Finish Thickness per Tracking Codes (µinches)

ID Code ID IAu Thickness (µin) EPd Thickness (µin) EN Thickness (µin)

1 I 2.07 3.48 349.32

2 II-SN13-3 2.2 5.49 343.83

3 II-SN13-4 2.54 6.84 371.24

4 III-SN7-2 2.9 1.57 190.3

5 III-SN7-3 2.15 6.38 175.14

6 III-SN7-4 3.3 8.32 182.84

7 IVB 1.64 5.78 176.75

8 IXB 0.77 9.95 190.16

9 XXB 0.72 16.26 176.21

10 VA 1.16 4.46 217.78

11 VIIA 1.82 7.76 212.54

12 VIIB 2.06 10.34 202.79

13 VIIIA 2.22 4.39 280.83

14 XB 1.42 7.48 267.04

15 XIB 1.68 11.01 254.14

16 XIIA 1.35 3.8 181.65

17 XXIB 1.24 5.93 184.07

18 XXII-2A 1.59 6.9 209.22

19 XXIVA 1.48 17.95 196.17

20 XXR 0.56 4.77 219.95

21 XXVA 0.73 7.37 236.76

January 2013 IPC-4556