Baseline wetting balance testing of four HT OSP coatings for generation of the IPC 4555 specification

Report Title

Baseline wetting balance testing of four HT OSP coatings for generation of the IPC 4555 specification  

Report ID #

4555_0

 

Date

08/07/2017

 

Name of Client

IPC 4-14 plating committee

Address

Chicago IL

       

Tested at

S T and S Testing and Analysis 108 Rosedale Ave Richmond KY 40475

Tested By

Gerard O’Brien President S T and S Group

Chairman of IPC 5-23 responsible for IPC J-STD 003,

Vice chairman of the 4-10 fabrication process committee

Co Chairman of IPC 4-14 Surface Finish Plating Committee,

 

Electronic Signature

 

 

 

The tests noted in the adjacent column, while necessary to complete the analysis,  are not currently accredited to ISO 17025:2005

 

 

 

Uncertainty Factor.

At this time we have determined that the uncertainty factor for tests in the adjacent column to be

 

Solderability Testing using a Wetting Balance: 0.00215 mN/mm

Optical measurement at 200X: 16.29µinches

T260, T288, T300 and TG measurement by DMA 0.78°C

XRF: values upon request

There are 28 pages in this report

Report is not to be reproduced except in full, without written approval of the laboratory

Table of Contents:

Summary and results……………………………………………………………………………………………..…4-5

Scope of test……………………………………………………………………………………………………………6

Table of figures:

Figure 1: summary of average and "best" results from the four OSP sample groups tested as received. 4

Figure 2: contact angle acceptance criteria. 4

Figure 3: average wetting force results for the four OSP samples tested as received. 5

Figure 4: average contact angle results for the four OSP samples tested as received. 5

Figure 5: sample R as received and the individual wrapping of the test vehicles inside the aluminum packaging  6

Figure 6: sample S as received and the internal packaging of the samples (slip sheeted and inside plastic bag) 7

Figure 7 sample T as received and the internal packaging of the samples (slip sheeted and inside plastic bag) 7

Figure 8: sample U as received and the internal packaging of the samples – slip sheeted no plastic packaging  7

Figure 9: merge of 17 tests for sample group R tested as received – wetting forces. 9

Figure 10: average of 17 tests for sample group R tested as received – wetting forces. 9

Figure 11: merge of 17 tests for sample group R tested as received- contact angles. 10

Figure 12: average of 17 tests for sample group R tested as received – contact angles. 10

Figure 13: the 17 test coupons from Sample Group R post initial testing side one. 11

Figure 14: the 17 test coupons from Sample Group R post initial testing side two. 11

Figure 15: 10X measurement of solder flow up sample group R coupon side 1 left side. 12

Figure 16: 10X measurement of solder flow up sample group R coupon side 1 right side. 12

Figure 17: 10X measurement of solder flow up sample group R coupon side 2 right side. 13

Figure 18: 10X measurement of solder flow up sample group R coupon side 2 left side. 13

Figure 19: merge of 18 tests for sample group S tested as received – wetting forces. 14

Figure 20: average of 18 tests for sample group S tested as received – wetting forces. 14

Figure 21: merge of 18 tests for sample group S tested as received – contact angles. 15

Figure 22: average of 18 tests for sample group S tested as received – contact 15

Figure 23: the 18 test coupons from Sample Group S post initial testing side one. 16

Figure 24: the 18 test coupons from Sample Group S post initial testing side two. 16

Figure 25: 10X measurement of solder flow up sample group S coupon side 1 left side. 17

Figure 26: 10X measurement of solder flow up sample group S coupon side 1 right side. 17

Figure 27: 10X measurement of solder flow up sample group S coupon side 2 left side. 18

Figure 28: 10X measurement of solder flow up sample group S coupon side 2 right side. 18

Figure 29: merge of 18 tests for sample group T tested as received – wetting forces. 19

Figure 30: average of 18 tests for sample group T tested as received – wetting forces. 19

Figure 31: merge of 18 tests for sample group T tested as received – contact angles. 20

Figure 32: average of 18 tests for sample group T tested as received – contact angles. 20

Figure 33: the 18 test coupons from Sample Group T post initial testing side one. 21

Figure 34: the 18 test coupons from Sample Group T post initial testing side two. 21

Figure 35: 10X measurement of solder flow up sample group T coupon side 1 left side. 22

Figure 36: 10X measurement of solder flow up sample group T coupon side 1 right side. 22

Figure 37: 10X measurement of solder flow up sample group T coupon side 2 right side. 23

Figure 38: 10X measurement of solder flow up sample group T coupon side 2 left side. 23

Figure 39: merge of 18 tests for sample group U tested as received – wetting forces. 24

Figure 40: average of 18 tests for sample group U tested as received – wetting forces. 24

Figure 41: merge of 18 tests for sample group U tested as received – contact angles. 25

Figure 42: average of 18 tests for sample group U tested as received – contact angles. 25

Figure 43: the 18 test coupons from Sample Group U post initial testing side one. 26

Figure 44: the 18 test coupons from Sample Group U post initial testing side two. 26

Figure 45: 10X measurement of solder flow up sample group U coupon side 1 left side. 27

Figure 46: 10X measurement of solder flow up sample group U coupon side 1 right side. 27

Figure 47: 10X measurement of solder flow up sample group U coupon side 2 right side. 28

Figure 48: 10X measurement of solder flow up sample group U coupon side 2 left side. 28

 

Summary and results:

All four sample groups produced positive wetting forces on average cross the zero line at 1 second.

The rate of rise of all four sample groups were very similar and it was only at the completion of the ten second test that any minor discrimination in wetting forces or contact angles was discernable.

The intra group consistency was excellent for all four samples with standard deviations of 0.01 mN/mm  being recorded for each time interval of the tests.

All samples tested showed positive advancement of solder flow up the coupon.

Sample #

Average time to cross zero line

Average maximum wetting force

Maximum wetting force

Average lowest contact angle

Lowest contact angle

Sample R

1 second

0.21 mN/mm

0.22 mN/mm

31 degrees

27 degrees

Sample S

1.125 seconds

0.19 mN/mm

0.20 mN/mm

36 degrees

32 degrees

Sample T

1.125 seconds

0.19 mN/mm

0.21 mN/mm

35 degrees

30 degrees

Sample U

1.125 seconds

0.21 mN/mm

0.23 mN/mm

31 degrees

20 degrees

Figure 1: summary of average and "best" results from the four OSP sample groups tested as received

 

Contact angle  Wettability                  
o to 30 degrees  Excellent
30 to 40 degrees Good
40 to 55 degrees Acceptable
Greater than 55 degrees Unacceptable   

 

Figure 2: contact angle acceptance criteria

 

 

 

Figure 3: average wetting force results for the four OSP samples tested as received

Figure 4: average contact angle results for the four OSP samples tested as received

Scope: Base line testing of the four OSP high temperature coatings to be used for the generation of the IPC 4555 OSP specification.

There are three chemical suppliers participating in the generation of the IPC 4555 OSP specification supplying four high temperature OSP coatings suitable for Pb-free assembly. The     4-14 committee has decided for this second attempt to generate an OSP specification to limit the scope significantly to Pb-free compatible OSP coatings and to test only with Pb-free solder.

The three suppliers, Atotech, MacDermid Enthone and Shikoku were requested to have these initial test vehicle samples coated and ready for shipping by July 28th 2017. This request was met and the samples duly arrived the following week at S T and S Group for sample coding and initial wetting balance testing. The four samples have been coded in no particular order as follows:

  1. Sample R
  2. Sample S
  3. Sample T
  4. Sample U

It is noted that all samples were submitted in similar “aluminum” bags, all vacuum sealed and containing desiccant. Two of the three suppliers returned the coated samples in a single package while the third supplier vacuum packaged smaller number of test vehicles in multiple packages.

For the initial baseline test, one test vehicle per OSP coating was removed from the original packaging and tested on Friday August 4th  2017. The remaining test vehicles were returned to their original foil bags, the bag material folded over and taped closed.

 

Figure 5: sample R as received and the individual wrapping of the test vehicles inside the aluminum packaging

     

Figure 6: sample S as received and the internal packaging of the samples (slip sheeted and inside plastic bag) 

   

Figure 7 sample T as received and the internal packaging of the samples (slip sheeted and inside plastic bag)

        

Figure 8: sample U as received and the internal packaging of the samples – slip sheeted no plastic packaging

The coupons were tested using a Metronelec ST 88 Wetting Balance and following the protocol detailed in the IPC JSTD003C WAM1 and identical to that used for the generation of the IPC4556 and IPC4552A specifications. There are eighteen (18) test coupons per test vehicle and these were removed using a shears to cut the breakaway tabs. For sample Group R,  only seventeen (17) samples were tested due to human error by the tester and not an issue with the sample itself.

Each coupon was immersed in to the Standard Test flux # 2 for five seconds with excess allowed to drain. Each coupon was then placed into a suitable tool holder and immersed at 90 degrees incident to the solder surface to a depth of 0.5mm. The dwell time in the SAC305 solder was ten (10) seconds at the prescribed test temperature of 255°C

 

Figure 9: merge of 17 tests for sample group R tested as received – wetting forces

 

Figure 10: average of 17 tests for sample group R tested as received – wetting forces

 

Figure 11: merge of 17 tests for sample group R tested as received- contact angles

 

Figure 12: average of 17 tests for sample group R tested as received – contact angles

 

Figure 13: the 17 test coupons from Sample Group R post initial testing side one

 

Figure 14: the 17 test coupons from Sample Group R post initial testing side two

 

Figure 15: 10X measurement of solder flow up sample group R coupon side 1 left side

Comments: immersion depth was 0.5 mm

 

Figure 16: 10X measurement of solder flow up sample group R coupon side 1 right side

Comments: immersion depth was 0.5 mm     

 

 

Figure 17: 10X measurement of solder flow up sample group R coupon side 2 right side

Comments: immersion depth was 0.5 mm   

 

Figure 18: 10X measurement of solder flow up sample group R coupon side 2 left side

Comments: immersion depth was 0.5 mm     

 

 

Figure 19: merge of 18 tests for sample group S tested as received – wetting forces

 

Figure 20: average of 18 tests for sample group S tested as received – wetting forces

 

Figure 21: merge of 18 tests for sample group S tested as received – contact angles

 

Figure 22: average of 18 tests for sample group S tested as received – contact

 

Figure 23: the 18 test coupons from Sample Group S post initial testing side one

 

Figure 24: the 18 test coupons from Sample Group S post initial testing side two

 

Figure 25: 10X measurement of solder flow up sample group S coupon side 1 left side

Comments: immersion depth was 0.5 mm   

 

Figure 26: 10X measurement of solder flow up sample group S coupon side 1 right side

Comments: immersion depth was 0.5 mm     

 

 

 

 

Figure 27: 10X measurement of solder flow up sample group S coupon side 2 left side

Comments:  immersion depth was 0.5 mm  

 

Figure 28: 10X measurement of solder flow up sample group S coupon side 2 right side

Comments: immersion depth was 0.5 mm

 

 

 

 

Figure 29: merge of 18 tests for sample group T tested as received – wetting forces

 

Figure 30: average of 18 tests for sample group T tested as received – wetting forces

 

Figure 31: merge of 18 tests for sample group T tested as received – contact angles

 

Figure 32: average of 18 tests for sample group T tested as received – contact angles

 

Figure 33: the 18 test coupons from Sample Group T post initial testing side one

 

Figure 34: the 18 test coupons from Sample Group T post initial testing side two

 

 

 

Figure 35: 10X measurement of solder flow up sample group T coupon side 1 left side

Comments: immersion depth was 0.5 mm

 

Figure 36: 10X measurement of solder flow up sample group T coupon side 1 right side

Comments: immersion depth was 0.5 mm     

 

 

 

 

Figure 37: 10X measurement of solder flow up sample group T coupon side 2 right side

Comments:  immersion depth was 0.5 mm  

 

Figure 38: 10X measurement of solder flow up sample group T coupon side 2 left side

Comments: immersion depth was 0.5 mm     

 

 

 

 

Figure 39: merge of 18 tests for sample group U tested as received – wetting forces

 

Figure 40: average of 18 tests for sample group U tested as received – wetting forces

 

Figure 41: merge of 18 tests for sample group U tested as received – contact angles

 

Figure 42: average of 18 tests for sample group U tested as received – contact angles

Figure 43: the 18 test coupons from Sample Group U post initial testing side one

 

Figure 44: the 18 test coupons from Sample Group U post initial testing side two

 

 

 

Figure 45: 10X measurement of solder flow up sample group U coupon side 1 left side

Comments: immersion depth was 0.5 mm   

 

Figure 46: 10X measurement of solder flow up sample group U coupon side 1 right side

Comments: immersion depth was 0.5 mm     

 

 

 

 

Figure 47: 10X measurement of solder flow up sample group U coupon side 2 right side

Comments: immersion depth was 0.5 mm   

 

Figure 48: 10X measurement of solder flow up sample group U coupon side 2 left side

Comments:  immersion depth was 0.5 mm