INTERNATIONAL MICROELECTRONICS AND PACKAGING SOCIETY Reliability of Solder Joint Quality on J-Lead Oscillators Using HALT with Lead and Lead Free Compositions Steve Laya Elite Electronic Engineering Todd Treichel Precision Devices, Inc.
Presentation Overview Primary Objective: Evaluation of Lead vs. Lead Free Use of HALT Vibration (and Thermal Shock) Initial Findings Sometimes things don t go as planned Understanding HALT Stresses Resonance Dwell To Determine Lead vs. Lead Free Post Test Analysis
Lead vs. Lead-Free Conversion from Lead to Lead-Free European Union Automotive Electronics Industrial and Commercial Electronics Assure reliability of Lead-Free
Published Research Follow up on PDI Testing Joint Council on Ageing Aircraft (JCAA)
J-Lead Ceramic Package Under Test
Test Vehicle PCB 10 parts Lead 10 parts Lead-Free J-Leaded Oscillators Hand Soldered To Fiberglass Epoxy PCB Lead Free Lead
Termination Diagram Electro Au, 1.00 µm Min. Kovar, 0.25 Min. Dia. Electro Ni, 1.78 µm Min. Cu FR4 Substrate Alloys Under Test Ag 3.0% Pb 37% Cu 0.5% Sn 63% Sn 96.5% Tin/Lead SAC 305 Solder
Solder Joint Inspection NASA-STD-8739.3
HALT Table Location Placed in the center of the HALT vibration table with Air Flow evenly distributed Instrumentation to measure open circuit on PCB component interface.
Instrumentation
Elite s HALT System HALT Testing 60C/m Temp Shock 6-Axis Vibration Repetitive Shock Power Spectral Density Characteristics HALT Test Purpose
6-Axis RS Vibration Table
Test Results Thermal Shock Step Vibe Sustained Vibration at 50gs No failures after 35 hours of vibration testing. How come???
Perform a Vibration Survey
Perform a Vibration Survey
Perform a Vibration Survey
Measure PCB Resonance
Lead-Free 3 Lead 2 4
Resonance Search Run 1 10 3 2 4 Demand (G) Ch2 (G) Ch3 (G) Ch4 (G) 1 Gs 0.1 10 100 1000 10000
Multiple Searches Location 3 3 2.5 2 1.5 Gs 1 Location 3 On PCB Near Mounting Bolt Run #2 PCB2 Loc3 Run #3 PCB2 Loc3 Run #1 PCB2 Loc3 0.5 0 1 10 100 1000 10000 Multiple Searches Location 4 12 10 8 6 Gs 4 Run #2 PCB1 Loc4 Run #3 PCB1 Loc4 Run #1 PCB1 Loc4 Location # 4 2 0 1 10 100 1000 10000
Measure resonance of the Oscillator On Chip (PCB2) With and Without Wax 8 Run #2 Accel Only 7 Run #3 Accel + Weight 6 5 Gs 4 3 2 1 0 0 500 1000 1500 2000 2500
Overlay resonance on plot of PSD Location 4 100 10 G 2 /Hz 1 0.1 PCB Response from HALT at 51.9g Control Sw ept Resonance 718.8, 23.3 726.2, 9.4 Location 2 Board 1- Ch4 1 10 100 1000 10000 100000 0.01 4 0.001 100 10 G 2 /Hz 1 HALT Inputl Sw ept Resonance PCB Response 0.1 0.01 0.001 1 10 100 1000 10000 100000 718.75, 0.543299
Overlay resonance on plot of PSD Location 3 100 10 G 2 /Hz 1 Sw ept Resonancel PCB Response from HALT at 51.5g Control 595.87, 2.00 1,371.88, 9.37 Location 1 Board 2 - Ch3 (Near Bolt) 1 10 100 1000 10000 100000 0.1 3 0.01 0.001 100 10 Sw ept Resonance HALT Input PCB Response G 2 /Hz 1 1 10 100 1000 10000 100000 0.1 0.01 0.001
Overlay resonance on plot of PSD Location 2 100 10 G 2 /Hz 1 0.1 Sw ept Resonance PCB Response from HALT at 51.0gsHALT Response 784.38, 15.15 Location 2 Board 2 - Ch2 1 10 100 1000 10000 100000 0.01 0.001 2 100 10 Sw ept Resonance PCB Response from HALT at 51.0gsHALT Response HALT Input Location 2 Board 2 - Ch2 G 2 /Hz 1 1 10 100 1000 10000 100000 0.1 0.01 0.001
100 10 Series2 Series3 Series4 Series1 Location 2 Board 2 -Ch2 (Center) 784.38, 15.15 1 0.1 1 10 100 1000 10000 100000 0.1 0.01 784.38, 0.456793 0.001
What is the Board Acceleration @ 718Hz Location 4 was at 23.3 g 2 /Hz RMS Acceleration at 718 (location 4) is Accel = (23.3 x 3.13) 1/2 = 8.6g @ 1371Hz Location 3, 9.37 g 2 /Hz Accel = (9.37 x 3.13) ½ = 5.4g @784 Hz Location 2, 15.15 g 2 /Hz Accel = (15.15 x 3.13) ½ = 6.8
Perform Resonance Dwell Pick a resonance Test to failure Determine time to failure
Lead-Free 3 Lead 2 4
Lead Free Resonance Dwell at 748Hz Loc 2 (Gs) Loc 3 (Gs) Control (Gs) Dwell (Min) 25-3 10 50-5.6 10 97 6.3 10 10 217 26 20 10 433 78 40 10 513 106 50 10 560 129 60 7 Total 67 An still no pop-off failures!
Solder Joint Inspection 96.5Sn/3.0Ag/0.5Cu 63Sn/37Pb 40% of Joints Fractured 22% of Joints Fractured
Conclusions & Lessons Learned Both constructions are durable HALT Suitable for generating high vibration on PCB components Good fixturing is important Resonance Dwell Concentrates enormous energy at one frequency Selection of resonance frequency could skew results. Test Uniformity & Repeatability Difficult to achieve Board Resonances Locations
INTERNATIONAL MICROELECTRONICS AND PACKAGING SOCIETY Any questions Thank you! Enjoy the remainder of the conference.