IPC 3-11g Mixed Flowing Gas (MFG) Creep Corrosion Benchmarking Test Preliminary Results Feb 2013

Objectives Replicate Alcatel-Lucent’s creep corrosion results Will use exactly the same conditions, test coupons and materials Improved MFG operating procedures

Test Vehicle FR4 4” x 5” x 0.063” 9 comb patterns – 7 on top, 2 on bottom 5 comb patterns with perpendicular solder mask strips 4 comb with PTHs – 2 with solder mask defined holes, 2 not Taiyo PSR4000 or equivalent solder mask

Surface Finish & Flux Surface finishes ROL0 solder paste True bare copper SnPb HASL OSP iAg ENIG ROL0 solder paste ORL0 & ROL0 wave fluxes

Test Matrix with # of Replicates Wave flux Surface Finish RO OR None Bare Copper 3 SnPb HASL OSP iAg ENIG

Before Testing… Handle by edges with nitrile gloves Check representative sample with IC as per IPC TM-650, Method 2.3.28 Visually inspect & document Vacuum seal with no paper or desiccant Non-contaminating marking Finish, flux, board #

Before Testing… Screen solder paste using 6 mil stencil Reflow once (record parameters) Uniform wave flux application with validated hole penetration (record parameters) Wave solder (record parameters) Coupons stored in clean aluminum foil, if required

Actual MFG Testing Clean chamber only if part of usual procedure (record parameters) Copper foil & ASTM B825-02 weighed (to nearest 0.01 mg) control samples Coupons & foils parallel to air flow in chamber Recorded, randomized placement 40C, 70-75% RH No bias 20 days

Actual MFG Testing - Gas Concentrations H2S SO2 NO2 Cl2 1700 ppb 200 ppb 20 ppb Like EIA IIIA but with elevated H2S

Immediate Post Test Work Weigh control foils Record amount of creep corrosion on coupons Wrap in Al foil Send off foils & coupons for further analysis

Further Post Test Analytical Work EDX identification of corrosion products from each surface finish/flux combination Remove corrosion products & inspect surfaces of coupons and foils Weigh cleaned foils and calculate corrosion rate ASTM B825-02 corrosion rates to be determined coulometrically

Appendices to the Test Method A – Measurement Techniques for Determining the Amount of Wave Solder Flux Applied B – Visual Inspection Criteria for Creep Corrosion Evaluation C – Worksheet for Reporting Board Inspection & Cleanliness Testing Prior to Preconditioning D – Worksheet for Reporting Preconditioning Results & Parameters E – Worksheet for Reporting Parameters from MFG Chambers F – Worksheet for Reporting Measurements & Experimental Results from MFG Tests G – Worksheet for Reporting Results form ASTM B825-02 Coupons H Procedure for Removing Corrosion Products

Test Sites CALCE Battelle Alcatel-Lucent (5d data only) Univ. of Limerick (data not plotted yet)

Different Types of Corrosion Observed Discoloration [Bare Copper –day 5] Creep [Immersion Silver–day 5] Flaking [Immersion Silver–day 20] Fiber assisted corrosion [Immersion Silver–day 5 White Patina [Bare Copper –day 10] Green Patina [Bare Copper –day 5]

Discoloration CALCE ALU Battelle Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Creep CALCE ALU Battelle Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Greening CALCE ALU (none) Battelle (none) Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Flaking CALCE ALU (none) Battelle Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

White CALCE ALU (none) Battelle Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Summary Data for Each Chamber

Results Creep Corrosion Results - CALCE Discoloration Creep Green Flaking White Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Results Creep Corrosion Results - Battelle Discoloration Creep Green Flaking White Board Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO

Results Discoloration Creep Green Flaking White Board Type Day 5 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3 ALCATEL LUCENT RESULTS

Backup

Creep Corrosion Classification PTH Creep Pre-Creep Build up of corrosion product to edge of solder mask Minor Creep Corrosion onto solder mask Severe Creep Corrosion forms film No Creep

Creep Corrosion Classification Creep on traces Minor Creep . Major Creep No Creep Minor – Corrosion product from trace on solder mask Major – Corrosion product from trace forms a film

Creep Corrosion Results - CALCE PTH: Minor Severe Trace: Pre-Creep Minor Severe Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO The shading Green to blue to red is a progression, so the numbers for each color do not go in order. Example: ImAg day 5 has 3 pre creep, day 10 has 2 pre-creep and 1 minor creep, day 15 has 1 pre creep, 1 minor creep and 1 major creep, day 20 has 2 minor creep and 1 major creep; it took one board 20 days to get minor creep. 3 out of 3 1 out of 3 2 out of 3

Trace: PTH: Minor Severe Pre-Creep Minor Severe 3 out of 3 1 out of 3 Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3 ALCATEL LUCENT RESULTS

Trace: PTH: Creep Corrosion Results - Battelle Pre-Creep Minor Severe Type Day 5 Day 10 Day 15 Day 20 Cu Cu-OR Cu-RO SnPb SnPb-OR SnPb-RO OSP OSP-OR OSP-RO ImAg ImAg-OR ImAg-RO ENIG ENIG-OR ENIG-RO 3 out of 3 1 out of 3 2 out of 3

Steps for corrosion classification Identify features of interest and features that will be used to differentiate between different corrosion phenomena Identify levels of corrosion and features that will be used to determine severity Examine samples, taking sample images when different corrosion phenomena occur or corrosion severity increases Combine results for all samples in a single graphic The following charts provide images of corrosion type and/or classification, an overview chart, and supporting documentation. Slides 3-6 cover overall corrosion. Slides 7-18 cover creep corrosion.