Power Temp Cycle Information Trent Uehling JUNE.9.2015

Comparison of Hardware Solutions Freescale (CC4) (CC5) Rel Inc (C20A) MCC (HPB5A) Unisys (ATS500) DUT Voltage Control / Monitor Yes Multiple DUT / PS DUT Thermal Control / Monitor DUT Heat Dissipation Up to 20+ Watts Up to 40+ Watts Up to 50 Watts Up to 150 Watts Up to 400 Watts Primary Current Per BIB 160 Amps (32 @ 5A or 8 @ 10A) 240 Amps (16 @ 15A or 8 @ 30A) 960 Amps (12 @ 80A) 800 Amps (8 @ 100A) 2250 Amps (15 @ 150A) Devices Per BIB 16 or 32 8 or 16 Up to 24 15 Slots Per System 60 24 16 8 DUT Per System Up to 1920 Up to 960 Up to 576 Up to 384 120 System Heat Dissipation 18KW 20KW 25KW 48KW Features Individual control BITT support It Works! Re-use of CC4 / C18HP Higher power Individual Control Higher power Issues Insufficient power Not sufficient for CPD Not yet designed Batch PS’s High capital $ Prototype Long lead time Best for short BI Poor track record Cost Medium High High / Very High Very High

Burn-in System Chamber Integrated Burn-in Environment Rel Inc C18HP upgrade High velocity airflow (>1000 lfpm) High thermal capacity (18kW @ 90C) 60 slots per system / 1.75” pitch Liquid cooling for better thermal control Four power supplies @ 20kW each Integrated Burn-in Environment Interface to driver Oven control Burn-in Board / Driver High density interconnect (HDI) Pwr / Gnd bars and power blocks Burn-in Board Driver HDI Bus Bar Power Block Backplane

Flip Chip Power Temp Cycle Model quarter symmetry considered Model considers center, edge and outermost corner C4 sphere Die and underfill layer transparent substrate model considers real routing design and metal coverage per layer Quarter symmetry used Substrate model reflects copper coverage per layer correctly

Simulated Scenarios Scenario # Loading Condition 1 Temperature Cycling -50°C to 150°C 2 Temperature Cycling 80°C to 125°C 3 Temperature Cycling 110°C to 125°C 4 Power Temp. Cycling 25°C to 85°C Underfill Tg Scenario 4 (considering 40°C temperature rise at junction during active phase) For scenario 4, a thermal analysis was conducted prior to the thermo-mechanical analysis step in order to calculate the temperature field over time required as a load The underfill material was considered using a visco-elastic material model Solder alloy SAC305 considered , using a visco-plastic material model

Assumed Power Cycling Transient thermal simulation was conducted first to extract temperature field over time required as the thermal load for the thermo-mechanical simulation. Temperature contour for powered phase Temperature contour for unpowered phase The temperature gradient over the package that results from powering the die, is a significant thermo-mechanical load increase which adds to the load from the CTE mismatch in the package.

Volume Averaging Creep Select volume with highest creep strain and volume average the accumulated creep strain of one temperature cycle. Eqv. creep strain contour excample of outermost corner sphere after 2 cycles 85°C to 125°C In order to compare the results, accumulated creep strain is averaged over full sphere volume as well as a small sphere segment that is impacted the most (thin segment at die side, usually the volume a fatigue crack would propagate through)

Max. Creep Strain over 1 Temperature Cycle The highest max. equivalent creep strain for one temperature cycle is found for power cycling test, (ambient temperature cycles from 25°C to 85°C) The results reveal that especially the junction temperature increases at high ambient temperature cause significant creep strain increase This is explained by the underfill material property changes above Tg (around 115°C)

45x45mm FC-PBGA Package Warpage - 3D Plots

45x45mm FC-PBGA Package Warpage - Diagonal Plots