IPC-4556 印制板化学镍钯浸金（ENEPIG）规范ENG - 第30页
260 250 240 230 220 210 200 200 190 170 160 Figure A3-4 Electroless Nickel Thickness Readings in Microinches for the Sixteen T est Pads Where C Is the Reference XRF 150 microinches Ni abc def gh test unit ijk lm n Means …
Figure A3-3 Electroless Palladium Thickness Readings in Microinches for the Sixteen Test Pads Where C Is the Reference
XRF
9
8
7
6
5
4
3
2
1
abcdef gh
test unit
ijklmn
microinches Pd
Means and Standard Deviations
Level Number Mean Std Dev Std Err Mean
a 16 2.72938 0.19526 0.04881
b 16 4.05625 0.26069 0.06517
c 16 3.20437 0.07192 0.01798
d 16 3.17687 0.08957 0.02239
e 16 2.65625 0.16721 0.04180
f 16 2.85875 0.15077 0.03769
g 16 1.50188 0.15715 0.03929
h 16 3.43562 0.31985 0.07996
i 16 3.50937 0.20959 0.05240
j 16 2.79438 0.60361 0.15090
k 16 2.48875 0.48485 0.12121
l 16 3.42500 0.20817 0.05204
m 16 3.60000 0.16733 0.04183
n 16 6.59625 1.24604 0.31151
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年率
单
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230
220
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200
190
170
160
Figure A3-4 Electroless Nickel Thickness Readings in Microinches for the Sixteen Test Pads Where C Is the Reference XRF
150
microinches Ni
abcdef gh
test unit
ijklmn
Means and Standard Deviations
Level Number Mean Std Dev Std Err Mean
a 16 167.777 2.71270 0.6782
b 16 162.850 2.70604 0.6765
c 16 210.259 3.19157 0.7979
d 16 183.289 1.91206 0.4780
e 16 201.806 3.30343 0.8259
f 16 195.055 5.64116 1.4103
g 16 195.575 1.84914 0.4623
h 16 207.644 2.34321 0.5858
i 16 207.906 2.16193 0.5405
j 16 188.837 4.13874 1.0347
k 16 190.637 3.09901 0.7748
l 16 159.694 3.62721 0.9068
m 16 156.775 2.75064 0.6877
n 16 234.000 6.01565 1.5039
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Results:
From the round robin testing, the following can be stated:
1) For Immersion Gold readings, the majority of the readings were on the high side with only one location reading the
thickness correctly. Two locations produced readings; one high and one low; that were so far out of the range as to be
meaningless.
2) For Electroless Palladium, four of the machines recorded readings that were correct with the majority of the other read-
ings being low. Again, one of the machines that produced meaningless gold readings also produced similar readings for
Palladium and maintained consistency regarding the error reading being low.
3) For the Electroless Nickel, there were eight participants that were within an acceptable range of the actual readings.
The remainder of the locations read the sample LOW.
In addition to this testing, another series of XRF measurements were taken to evaluate the impact of feature size on the
deposit thickness plated at the same time on the same board. The board was again measured on the same reference XRF
unit. A summary of the results is shown in Figure A3-5.
Table A3-1 Comparison of the Accuracy of Measurements Relative to the C Readings for All Three Deposits
XRF machine Nickel Thickness Palladium Thickness Gold Thickness
A Low Low High
B Low High High
C Correct Correct Correct
D Low Correct High
E Correct Low High*
F Correct Low High
G Correct Low* Low*
H Correct Correct High
I Correct Correct High
J Low Low Low
K Correct Low Low
L Low Correct High
M Low High Correct
N Correct High* High
*Note: Readings were so far out as to be meaningless
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