IPC-4556 印制板化学镍钯浸金（ENEPIG）规范ENG.pdf - 第8页
Figures Figure 3-1 Uniform Plating .............................................. 5 Figure 3-2 Extraneous Plating or Nickel Foot ................. 5 Figure 3-3 Edge Pull Back .............................................…
Table of Contents
1 SCOPE ...................................................................... 1
1.1 Statement of Scope .............................................. 1
1.2 Description ........................................................... 1
1.2.1 Electroless Nickel Reducing Agents -
Phosphorus Content ............................................. 1
1.2.2 Electroless Palladium Reducing Agents ............. 1
1.3
1.3.1
Objective .............................................................. 1
Order of Precedence ............................................ 1
1.3.1.1
Appendices ........................................................... 1
1.4
1.4.1
1.4.2
1.4.3
Performance Functions ........................................ 1
Solderability ......................................................... 1
Wire Bonding ....................................................... 2
Contact Surface .................................................... 2
1.4.3.1
Membrane Switches ............................................. 2
1.4.3.2
Metallic Dome Contacts ...................................... 2
1.4.4
EMI Shielding ...................................................... 2
1.4.5 Interface for Conductive and/or Anisotropic
Adhesives ............................................................. 2
1.4.6
Connectors ........................................................... 2
1.4.6.1
Press-Fit Applications .......................................... 2
1.4.6.2
Edge Tab Contact Applications ........................... 2
1.4.7
Limitations of ENEPIG ....................................... 2
1.4.7.1
Creep Corrosion/Chemical Resistance ................ 2
1.4.7.2
High Frequency Signal Loss ............................... 3
2 APPLICABLE DOCUMENTS AND TERMS AND
DEFINITIONS
............................................................ 3
2.1
IPC ....................................................................... 3
2.2 American Society for Testing and Materials
(ASTM International) .......................................... 3
2.3
2.4
2.5
JEDEC .................................................................. 3
Defense Standardization Program ....................... 3
Telcordia Technologies, Inc. ................................ 3
2.6 International Organization for Standardization
(ISO) ..................................................................... 3
2.7
Terms, Definitions and Acronyms ....................... 4
3 REQUIREMENTS ...................................................... 4
3.1
3.1.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
Visual ................................................................... 5
High Magnification Reference Images ............... 6
Finish Thickness .................................................. 7
Electroless Nickel Thickness ............................... 7
Electroless Palladium Thickness ......................... 7
Immersion Gold Thickness .................................. 7
XRF Calibration Standards ................................. 8
3.2.5 Use of Non-Statistical Thickness
Specification ......................................................... 8
3.2.6
3.3
3.4
3.5
Production Overruns and/or Inventory Items ..... 8
Porosity ................................................................ 8
Adhesion .............................................................. 8
Solderability ......................................................... 9
3.5.1 Force Measurement Testing (Wetting Balance
Testing) ................................................................. 9
3.6
3.7
Cleanliness ........................................................... 9
Electrolytic Corrosion .......................................... 9
4 QUALITY ASSURANCE PROVISIONS .................... 9
4.1
4.1.1
4.1.2
4.2
4.2.1
4.2.2
General Quality Assurance Provisions ................ 9
Qualification Recommendations .......................... 9
Sample Test Coupons ........................................ 10
Quality Conformance Testing ............................ 11
Thickness Measurements ................................... 11
Qualified Processes ............................................ 11
APPENDIX 1 Chemical Definitions and Process
Sequence
.......................................... 12
APPENDIX 2 Round Robin Test Summary ........... 14
APPENDIX 3 ENEPIG PWB Surface Finish XRF
Round Robin Testing
....................... 16
APPENDIX 4 Factors Affecting Measurement
Accuracy of ENEPIG Coatings
by XRF
............................................... 23
APPENDIX 5 ENEPIG PWB Surface Finish
Wetting Balance Testing
.................. 32
APPENDIX 6 Solder Spread Testing ..................... 40
APPENDIX 7 ENEPIG PWB Surface Finish
Shear Test Project
............................ 48
APPENDIX 8 Gold Wire Bonding .......................... 58
APPENDIX 9 XRF Thickness Measurements
of thin Au and Pd (ENEPIG):
Recommendations for
Instrumentation (Detectors)
and their Limitations
........................ 64
APPENDIX 10 Gage Capability. Gage R&R
Type 1 Study
..................................... 66
APPENDIX 11 Solderability Testing Helps Select
Surface Finishes
............................... 69
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Figures
Figure 3-1 Uniform Plating .............................................. 5
Figure 3-2 Extraneous Plating or Nickel Foot ................. 5
Figure 3-3 Edge Pull Back .............................................. 5
Figure 3-4 Skip Plating .................................................... 5
Figure 3-5 Skip Plating of Gold Over Palladium ............. 6
Figure 3-6 Skip Plating of Gold Over a Palladium
Deposit ........................................................... 6
Figure 3-7 1000X SEM Image of a Normal ENEPIG
Surface ........................................................... 6
Figure 3-8 4000X SEM Image of a Normal ENEPIG
Surface ........................................................... 6
Figure 3-9 2500X FIB Image of a Normal ENEPIG
Deposit ........................................................... 6
Figure 3-10 100,000X FIB Image of a Normal ENEPIG
Deposit ........................................................... 6
Figure 3-11 TEM Image of a Normal ENEPIG Deposit .... 7
Figure 3-12 2500X Image of Nickel that is
Hyper-Corroded ............................................. 7
Figure 3-13 The Standard IPC Force Measurement
Coupon ........................................................... 9
Figure A3-1 Test Coupon Used for XRF Round Robin
Measurements ............................................. 16
Figure A3-2 Immersion Gold Thickness Readings in
Microinches for the Sixteen Test Pads
Where C Is the Reference XRF ................... 18
Figure A3-3 Electroless Palladium Thickness Readings
in Microinches for the Sixteen Test Pads
Where C Is the Reference XRF ................... 19
Figure A3-4 Electroless Nickel Thickness Readings
in Microinches for the Sixteen Test Pads
Where C Is the Reference XRF ................... 20
Figure A3-5 The Impact of Feature Size on Electroless
Palladium and Immersion Gold Deposition
Thickness Plated on the Same PB .............. 22
Figure A4-SS1 XRF Spectra of 1/2 oz Cu/Epoxy vs.
1 oz Cu/Epoxy ............................................. 28
Figure A4-SS2 XRF Spectra of ENEPIG Plated on Cu
(No Epoxy) vs. 1/2 oz Cu/Epoxy ................. 29
Figure A4-SS3 XRF Spectra of ENEPIG Plated on Cu
(No Epoxy) vs. ENEPIG Plated on 1 oz
Cu/Epoxy ...................................................... 30
Figure A4-SS4 XRF Spectrum of ENEPIG Plated on
1 oz Cu/Epoxy ............................................. 31
Figure A5-1 Example of the Wetting Balance Coupon
Used for the Testing of ENEPIG .................. 32
Figure A5-2
XRF Measurements of Gold and
Palladium Thicknesses Supplied
as Nominal 0.1 micron Electroless
Palladium ..................................................... 33
Figure A5-3
XRF Measurements of Gold and
Palladium Thicknesses Supplied
as Nominal 0.2 micron Electroless
Palladium ..................................................... 33
Figure A5-4
XRF Measurements of Gold and
Palladium Thicknesses Supplied
as Nominal 0.3 micron Electroless
Palladium ..................................................... 33
Figure A5-5
Metronelec ST88 Wetting Balance
Used for the Testing ..................................... 33
Figure A5-6 Example of the Wetting Performance for
a Nominal 4 µin Electroless Palladium
Tested with SnPb Solder .............................. 34
Figure A5-7 Example of the Wetting Performance for
a Nominal 8 µin Electroless Palladium
Tested with SnPb Solder .............................. 34
Figure A5-8 Example of the Wetting Performance for
a Nominal 20 µin Electroless Palladium
Tested with SnPb Solder .............................. 35
Figure A5-9 Example of the Wetting Performance for
a Nominal 4 µin Electroless Palladium
Tested with SAC305 Solder ......................... 35
Figure A5-10 Example of the Wetting Performance for
a Nominal 8 µin Electroless Palladium
Tested with SAC305 Solder ......................... 36
Figure A5-11 Example of the Wetting Performance for
a Nominal 12 µin Palladium Tested with
SAC305 Solder ............................................ 36
Figure A5-12 Example of a Nominal 4 µin Electroless
Palladium ENEPIG Post Temperature and
Humidity Stressing, Tested with SnPb -
Showing Excellent Robustness .................... 37
Figure A5-13 Example of a Nominal 4 µin Electroless
Palladium ENEPIG, with Very Thin
Immersion Gold after Temperature and
Humidity Stressing & Tested with SnPb ...... 38
Figure A5-14 Example of a Nominal 6 µin ENEPIG
Deposit Tested with SAC305 Post
Stressing – Showing Excellent
Robustness of Deposit ................................. 38
Figure A5-15 Performance of Sample Group 20 (with
thin gold) with SAC305 Post Stressing ........ 39
Figure A6-1 Layout of Test Board Used for Solder
Spread and Wetting Balance Testing .......... 41
Figure A6-2
Solder Spread Pattern and Paste Stencil .... 41
Figure A6-3 An Actual Solder Spread Result Showing
the Deposits Counted for Each Line of
the Pattern ................................................... 42
Figure A6-4 Solder Spread Results Using an ROL1
Sn/Pb/Ag Solder Paste on ENEPIG
Deposits ....................................................... 43
Figure A6-5 Solder Spread Results Using an ROL0
Pb-free Solder Paste of the SAC 300
Family on ENEPIG Deposits ........................ 44
Figure A6-6 Solder Spread for Lowest Spread ENEPIG
Sample Showing Evidence of High Contact
Angle and Dewetting for Some Areas of
the Printed Board ......................................... 45
Figure A6-7 Solder Spread Results for Pb-free Solder
Paste as a Function of the EN Layer
Thickness in the ENEPIG Deposit ............... 46
Figure A7-1
Shear Test Coupon ...................................... 48
Figure A7-2
DAGE 5000 Shear Test System .................. 49
Figure A7-3
Solderball Shear Results ............................. 49
Figure A7-4
Sn63Pb37 Test Coupon 19 .......................... 52
Figure A7-5
Sn63Pb37 Test Coupons1&2 ................... 52
Figure A7-6
Sn63Pb37 Test Coupons3&4 ................... 52
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Figure A7-7 Sn63Pb37 Test Coupons5&6 ................... 53
Figure A7-8 Sn63Pb37 Test Coupons7&8 ................... 53
Figure A7-9 Sn63Pb37 Test Coupon 18 .......................... 53
Figure A7-10 Sn63Pb37 Test Coupon 19 .......................... 54
Figure A7-11 SAC305 Test Coupons1&2....................... 54
Figure A7-12 SAC305 Test Coupons3&4....................... 54
Figure A7-13 SAC305 Test Coupons5&6....................... 55
Figure A7-14 SAC305 Test Coupons 16 & 17 ................... 55
Figure A7-15 SAC305 Test Coupon 18 ............................. 55
Figure A7-16 SAC305 Test Coupon 19 ............................. 56
Figure A7-17 Solderball Shear Force as a Function of
Palladium Plating Thickness ........................ 56
Figure A8-1 Wire Bond Test Vehicle Showing pin #1,
quadrants 1, 2, 3 and 4 ............................... 58
Figure A8-2 Example of 6 inx8inPanel Containing
1 in x 1in ENEPIG Wire Bond Coupons ...... 60
Figure A8-3 Visual Evaluation of Wire Bonding
Showing Classical Crescents Resulting
in Neck Breaks ............................................. 61
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 ......................... 62
Figure A11-1a Meniscometer ............................................... 70
Figure A11-1b
Wetting Balance ........................................... 70
Figure A11-2 ENEPIG with Thin and Thick Pd from
Vendors1&2 .............................................. 71
Figure A11-3 Wetting Rate as a Function of Battelle
Class 2 Aging ............................................... 72
Tables
Table 3-1 Requirements of Electroless Nickel Electroless
Palladium Immersion Gold (ENEPIG) Plating ... 4
Table 4-1
Suggested Fabricator Qualification Plan ......... 10
Table 4-2 C=0 Sampling Plan (Sample Size for Specific
Index Value
1
) .................................................... 11
Table A3-1 Comparison of the Accuracy of Measurements
Relative to the C Readings for All Three
Deposits ........................................................... 21
Table A4-1 Summary of XRF Configuration Solutions
Offered for Measurement of ENEPIG
Plating on PCB’s with Advantages and
Disadvantages ................................................. 27
Table A5-1 XRF Measurements of the Nominal
0.5 micron Electroless Palladium
Samples ........................................................... 32
Table A6-S1 Preconditioning and Solder Paste Matrix
Used for Solder Spread Testing for a
Given ENEPIG Chemistry and Electroless
Palladium Thickness ........................................ 40
Table A7-1 Test Coupon Serial Number and Palladium
Thickness ......................................................... 48
Table A7-2 Sn63Pb37 Solderball Shear Test Results
Coupon Set 1 (grams) ..................................... 50
Table A7-3 Sn63Pb37 Solderball Shear Test Results
Coupon Set 2 (grams) ..................................... 50
Table A7-4 SAC305 Solderball Shear Test Results
Coupon Set 1 (grams) ..................................... 51
Table A7-5 SAC305 Solderball Shear Test Results
Coupon Set 2 (grams) ..................................... 51
Table A8-I Twenty-one Panels Marked (a) Whole
Panel, (b) Array and (c) Hand Cut ................... 59
Table A8-II Destructive Wire Bond Pull Test Force
(grams) Results for All 21 ENEPIG
Test Groups ..................................................... 60
Table A8-III Summary of Plating Finish Thicknesses for
Samples Wire Bonded ..................................... 63
Table A9-1 XRF Detectors and Their Limitations at
Typical Count Rates ......................................... 64
Table A11-1 ‘‘Relative Wettability Guideline,’’ Using
Contact Angle (θ
C
) As ‘‘General’’ Metric .......... 70
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