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FVTX Substrate FEA during Power Outage. C. M. Lei October 06, 2006. Goals. To use FEA as a design tool to understand if the module and substrate are structurally safe during power outage. The Layup of the Multi-chip Module. Substrate (.12 cf + .38 tpg + .12 cf = .62 mm).
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FVTX Substrate FEAduring Power Outage C. M. Lei October 06, 2006
Goals • To use FEA as a design tool to understand if the module and substrate are structurally safe during power outage
The Layup of the Multi-chip Module Substrate (.12 cf + .38 tpg + .12 cf = .62 mm)
Effective Heat flux from ROC = 5.868 mW/mm^2 Effective heat flux from sensor = 0.25 mW/mm^2 Total heat load = 2.8W for half model FEA Model Half Modules with 4 chips (took advantages of symmetry and all modules evenly positioned) Cooling contact area 5mm wide at +7C Bump bond layer were modeled as a continous layer with adjusted properties based on an area ratio 21.33 (with eutectic solder bond diameter 0.035 mm assumed).
Material Library Used in this FEA Young’s modulus E, MPa Poison’s ratio n Thermal k, w/m-K CTE a, /K HDI 30e3 0.30 0.26 17e-6 Silicone glue 2 0.36 0.24 100e-6 Silicon sensor 110e3 0.30 141 2.6e-6 Silicon ROC 110e3 0.30 141 2.6e-6 TPG 83e3 0.20 table -1e-6 Eutectic solder 32e3 0.051 24.7e-6 All materials were assumed to be isotropic with constant properties except - TPG in which the thermal conductivity varies - Anisotropic carbon fiber facing and bump bonds TPG Thermal K Temp in K K in W/m-K Carbon fiber 0/90facing: Einplane = 1.48e5 Mpa, Eout-of-plane =7445 Mpa, kinplane= 55.85 W/mK, kout-of-plane = 0.69 W/mK, ainplane = -0.04e-6 ppm/K, aout-of-plane=30.17e-6 ppm/K Eutectic solder bump bond layer: Ex = Ez = 0.15 Mpa, Ey = 1500 Mpa, kx = kz = 0.33e-3 W/mK, ky = 2.38 W/mK, a = 24.7e-6 ppm/K
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Heat Load = 0W , Half Model with 4 chips When heat load = 0, Temperature everywhere is equal to the coolant temperatue at +7C
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone When heat load = 0, Temperature everywhere at +7C Max resultant disp. = 86.8 microns Max displacement of silicon = 55.3 mircons
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Stress Z Plot (out-of-plane 900direction) TPG Layer Max Resultant Stress = 2.5 Mpa Max Stress_Z = 0.1 Mpa Flexural Strenth = 36.7 Mpa Z = 38.5 Mpa // Tensile Strength < 0.69 Mpa Z = 6,897 Mpa //
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Stress Z Plot (out-of-plane 900direction) Carbon Fiber Layer Max Resultant Stress = 5.3 Mpa Max Stress_Z = 0.1 Mpa Flexural Strenth = 669 Mpa 00 Tensile Strength =1950 Mpa 00 = 28 Mpa 900
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Silicone Glue Layers between HDI and Substrate and between HDI and Module Max Stress = 0.07 Mpa Strength_NEE001 = 1.1 Mpa
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone HDI Layer Max Stress = 4.9 Mpa Tensile Strength_Kapton = 166 Mpa Tensile Strength_Copper = 320 MPa
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Sensor and ROC Layers Max Stress = 3.3 Mpa Strength_Si = 120 MPa
OK! RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm 7oC COOLING AT ENDS, POWER OUTAGE with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Max resultant stress = 0.383*21.33 = 8.2 Mpa Bump Bond Layer Strength of eutect solder Tensile Yield = 43 Mpa Ultimate = 52 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Max resultant disp. = 128 microns Max displacement of silicon = 81.4 mircons
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Stress Z Plot (out-of-plane 900direction) TPG Layer Max Resultant Stress = 3.7 Mpa Max Stress_Z = 0.17 Mpa Flexural Strenth = 36.7 Mpa Z = 38.5 Mpa // Tensile Strength < 0.69 Mpa Z = 6,897 Mpa //
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Carbon Fiber Layer Max Resultant Stress = 7.7 Mpa Max Stress_Z = 0.15 Mpa Flexural Strenth = 669 Mpa 00 Tensile Strength =1950 Mpa 00 = 28 Mpa 900 Stress Z Plot (out-of-plane 900direction)
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Silicone Glue Layers between HDI and Substrate and between HDI and Module Max Stress = 0.11 Mpa Strength_NEE001 = 1.1 Mpa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! HDI Layer Max Stress = 7.2 Mpa Tensile Strength_Kapton = 166 Mpa Tensile Strength_Copper = 320 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Sensor and ROC Layers Max Stress = 4.8 Mpa Strength_Si = 120 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at 0oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Max resultant stress = 0.564*21.33 = 12.0 Mpa Bump Bond Layer Strength of eutect solder Tensile Yield = 43 Mpa Ultimate = 52 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Max resultant disp. = 245 microns Max displacement of silicon = 156 mircons
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! TPG Layer Max Resultant Stress = 7.1 Mpa Max Stress_Z = 0.3 Mpa Flexural Strenth = 36.7 Mpa Z = 38.5 Mpa // Tensile Strength < 0.69 Mpa Z = 6,897 Mpa // Stress Z Plot (out-of-plane 900direction)
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Carbon Fiber Layer Max Resultant Stress = 14.8 Mpa Max Stress_Z = 0.29 Mpa Flexural Strenth = 669 Mpa 00 Tensile Strength =1950 Mpa 00 = 28 Mpa 900 Stress Z Plot (out-of-plane 900direction)
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Silicone Glue Layers between HDI and Substrate and between HDI and Module Max Stress = 0.21 Mpa Strength_NEE001 = 1.1 Mpa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! HDI Layer Max Stress = 13.7 Mpa Tensile Strength_Kapton = 166 Mpa Tensile Strength_Copper = 320 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Sensor and ROC Layers Max Stress = 9.3 Mpa Strength_Si = 120 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at -20oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Max resultant stress = 1.08*21.33 = 23.0 Mpa Bump Bond Layer Strength of eutect solder Tensile Yield = 43 Mpa Ultimate = 52 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone Max resultant disp. = 76.9 microns Max displacement of silicon = 49 mircons
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! TPG Layer Max Resultant Stress = 2.2 Mpa Max Stress_Z = 0.07 Mpa Flexural Strenth = 36.7 Mpa Z = 38.5 Mpa // Tensile Strength < 0.69 Mpa Z = 6,897 Mpa // Stress Z Plot (out-of-plane 900direction)
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Carbon Fiber Layer Max Resultant Stress = 4.6 Mpa Max Stress_Z = 0.2 Mpa Flexural Strenth = 669 Mpa 00 Tensile Strength =1950 Mpa 00 = 28 Mpa 900 Stress Z Plot (out-of-plane 900direction)
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Silicone Glue Layers between HDI and Substrate and between HDI and Module Max Stress = 0.07 Mpa Strength_NEE001 = 1.1 Mpa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! HDI Layer Max Stress = 4.3 Mpa Tensile Strength_Kapton = 166 Mpa Tensile Strength_Copper = 320 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Sensor and ROC Layers Max Stress = 2.9 Mpa Strength_Si = 120 MPa
RESULTS WITH CF/TPG/CF SUBSTRATE 0.62 mm (0.12+0.38+0.12) mm No coolant flow, Power Outage with Surrounding Temperature at +35oC Substrate Glue: 2 Mpa silicone; Module Glue: 2 Mpa silicone OK! Max resultant stress = 0.339*21.33 = 7.2 Mpa Bump Bond Layer Strength of eutect solder Tensile Yield = 43 Mpa Ultimate = 52 MPa
Remarks • when power supply to chips is off but coolant is still running, substrate and modules are all in coolant temperture 7C . This is bascially independent on surrounding temperature. (if possible, the coolant temperature should be set back to room temperature to eliminate any thermal effects.) • When power supply to chips is off and coolant is not running, substrate and modules are all basically at the same temperature as of the surrounding. • All stresses were within the tensile range when surrounding temperature was between -20C and +35C. • FEAs were done based on an assumption that a compliant low-modulus (E = 2 Mpa) adhesive can be used. Results would be different if the final choice of adhesives are different.