IPC-4556 印制板化学镍钯浸金（ENEPIG）规范ENG.pdf - 第41页

Above Figure A4-SS-4 shows typical ENEPIG plated on one ounce Cu/epoxy sample when measured with a pin diode detec- tor . Note how Au L- β and Br K- α peaks are better resolved and the Au L- α peak is visible and distinc…

Above Figure A4-SS-3 displays spectrum from typical ENEPIG plated on pure Cu (no epoxy) and typical ENEPIG plated

on one ounce Cu/epoxy (red trace). In the case of ENEPIG on one ounce Cu, the Br peak is added to the Au peak (seen in

blue with no Br interference). The red peak (Br + Au) is higher which results in a higher thickness measurement if peak

deconvolution is not used. Also note the Pd peak. The red Pd peak from the once ounce Cu sample is slightly higher than

the blue Pd peak because the background level scattered from the epoxy base raises the Pd peak a bit higher. Again with-

out correction or proper calibration, this would be interpreted as slightly higher Pd thickness. Both effects will vary as the

Cu thickness varies. Also x-ray beam size and position on the sample relative to its edges can affect the level of these inter-

ferences.

Figure A4-SS3 XRF Spectra of ENEPIG Plated on Cu (No Epoxy) vs. ENEPIG Plated on 1 oz Cu/Epoxy

Smoothed, Comparison of ENEPIG Cu.cts(blue) vs.ENEPIG one ounce Cu.sts(red)

0.9

655

524

393

No Br in blue

trace. Au + Br

in red trace

~ 4 mi Pd peak with

different background noise

262

131

8.4 15.8

Count

KeV

23.330.7 38.2

IPC-4556 January 2013

Spectral Analysis Mode- WPHA

Ele Edt Yew Display Ogerations ROI Help

ENIPIG_102C]

认Ｄｌ

BLUE

Chs 854.5

Peak(Ch.,KeV,Cts)

１９１，８．０，１２５６０．２

Ready

箱笛笛萄简

NUM[

Above Figure A4-SS-4 shows typical ENEPIG plated on one ounce Cu/epoxy sample when measured with a pin diode detec-

tor. Note how Au L-β and Br K-α peaks are better resolved and the Au L-α peak is visible and distinct from Cu K-β, allow-

ing measurement of Au intensity without need for peak overlap corrections like peak deconvolution. Also note clear Pd peak

with low background noise.

Figure A4-SS4 XRF Spectrum of ENEPIG Plated on 1 oz Cu/Epoxy

ENEPIG pin diode.cts

2.7

16005

12804

9603

6402

3201

7.4 12.1

Count

KeV

16.8 21.6 26.3

January 2013 IPC-4556

Spectral Analysis Mode·WPHA

Ele Edt Yiew Display Ogerations BOl Help

FLE 1:ENIPIG_pin diode.cts

Kev5.9

Mn [Ka]

Cts 226.5

Peak (Ch.,KeV,Cts)

１９５，８．２，４５６５３．２

△

Ready

　Ｌ　ｋ

NUMI

APPENDIX 5

ENEPIG PWB Surface Finish

Wetting Balance Testing

Gerard O’Brien, President

S T and S Group.

INTRODUCTION

Consistent with all previous speciﬁcation generations by the 4-14 Subcommittee for PWB surface ﬁnishes, solderability test-

ing using a wetting balance was performed to evaluate ENEPIG both in the ‘‘as received’’ condition and post temperature/

humidity stressing. There were six chemical suppliers who submitted samples for testing and because of their geographical

locations and the time needed to complete the plated test vehicles, some sample groups had signiﬁcant ‘‘shelf life’’ prior to

testing of up to eight months. During this time, the samples remained in their original packaging.

Test Vehicle The 4-14 Subcommittee which works closely

with the 5-23A Task Group has settled on a wetting balance

coupon that has changed little over the last 5 years or so. The

latest iteration of the test coupon was built with 18 wetting

balance coupons and four ball shear coupons per array (see

Figure A5-1). The wetting balance coupon also contains the

NPL spread test vehicle, which was also used during the gen-

eration of this speciﬁcation and retains through holes at the

opposite side (which were not used in these tests). The acid

copper plating and soldermask operations required to fabricate

these coupons were generously provided to the group by Mr.

Luc Beauvillier, who was then with Via Systems - Oregon.

Following extensive intra-committee discussions on the target thicknesses for the speciﬁcation, it was proposed that initial

testing would be on samples plated to the following thickness requirements:

1) Electroless Nickel - 6 microns ± 1 micron

2) Electroless Palladium - 0.1, 0.2 and 0.3 microns nominally - no tolerance was set

3) Immersion Gold - the thickness would be ‘‘as supplied’’

4) Electroless Palladium at 0.5 microns nominal from two of the six suppliers, in order to evaluate a ‘‘heavy’’ palladium

Figure A5-1 Example of the Wetting Balance Coupon

deposit (see Table A5-1)

Six chemical suppliers took part by providing plated test vehicles:

1) Atotech

2) Dow Electronic Materials

3) Enthone

4) MacDermid

5) OMG

6) Uyemura (both U.S. and Japanese plated)

Used for the Testing of ENEPIG

Table A5-1 XRF Measurements of the Nominal 0.5 micron Electroless Palladium Samples

Supplier Identiﬁer

Immersion Gold

Thickness (microns)

Electroless Palladium

Thickness (microns)

Electroless Nickel

Thickness (microns)

Target Thickness Per individual supplier 0.5 5 - 6

F 0.038 0.51 4.98

G 0.016 0.45 6.67

IPC-4556 January 2013