TIMAwave a novel test stand for thermal diffusivity measurement based on the Angstrom s method

Transcription

1 1 TIMAwave a novel test stand for thermal diffusivity measurement based on the Angstrom s method 12th European Advanced Technology Workshop on Micropackaging and Thermal management La Rochelle, France

2 Motivation In electronic packages and systems several materials and material combinations are used:» Semiconductors (SiC, GaN, Si, non-doped, doped, highly doped)» Metals (cooler, heat spreaders, metallization, )» Substrates (ceramics, polymers, )» Die attaches (solder, sinter, adhesive, )» TIMs (silicone based, metal based, carbon based, )» Reliable material data are needed for:» Feedback to material developers» Material selection» Input for simulation» Datasheets» Solder Heater Cu Heat spreader TIM 1 Si Chip Substrate Heater Al Heat sink TIM 2 cooler 2 Cu Heat spreader Underfill

3 Our solutions for reliable material data - Overview 3 TIMA LaTIMA TIMAwave Steady state measurement Steady state measurement Transient measurement Measurement of bulk thermal conductivity of low and middle thermally conductive materials Measurement of thermal interface resistance For solid and viscus materials Substrate (e.g. FR4, IMS, LTCC, HTCC, ) TIM (e.g. adhesive, grease, gap filler, films, ) Isolation layers Measurement of bulk thermal conductivity of middle and high thermally conductive materials For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys In-plane measurement Measurement of thermal diffusivity of all solid materials from low to highly conductive For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys In-plane measurement Thermal conductivity and diffusivity of all package material types can be provided by these test stands

4 Our solutions for reliable material data (1) TIMA 4 TIMA LaTIMA TIMAwave Steady state measurement Steady state measurement Transient measurement Measurement of bulk thermal conductivity of low and middle thermally conductive materials Measurement of thermal interface resistance For solid and viscus materials Substrate (e.g. FR4, IMS, LTCC, HTCC, ) TIM (e.g. adhesive, grease, gap filler, films, ) Isolation layers Measurement of bulk thermal conductivity of middle and high thermally conductive materials For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys Measurement of thermal diffusivity of all solid materials from low to highly conductive For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys Thermal conductivity and diffusivity of all package material types can be provided by these test stands

5 Lower reference body Heat flow Q Upper reference body TIMA Thermal Interface Materials Analyzer 5 Thermal conductivity measurement of low to middle thermally conductive materials T Rth eff Q Rtheff Rthbulk Rth 0 1 Rtheff BLT A bulk Rth 0 Heater T1 T2 T3 (\textit{$\delta$t}) T3 Sample Rth 0.1 Rth bulk Rth eff T4 T4 Rth 0.2 T5 Rth 0 ~ 1 bulk T6 Cooler BLT Results: Bulk thermal conductivity and thermal interface resistance

6 Lower reference body Upper reference body Unique selling point of TIMA (1) 6 Characterization under real or under desired conditions Different metals of reference bodies can be used Surface finishes and quality can be manipulated Heater T1 T2 T3 Adhesives can also be measured T4 T5 In-situ investigation of aging behavior of TIM compression F RB TIM RB expansion RB TIM RB T6 Cooler

7 Reference body Lower reference body Upper reference body Unique selling point of TIMA (2) 7 Measurement between silicon metal surfaces real application for TIM1 In-house developed thermal test chip with integrated heater and temperature sensors Heater T1 TTC Tc T1 Sample T2 T3 T2 T4 Bulk thermal conductivity can be found in datasheets, but not the thermal interface resistance TIMA provides these values measured under real conditions T3 Cooler T5 T6 Cooler

8 Adhesive 01 Adhesive 02 Adhesive 03 Adhesive 04 PCM 01 PCM 02 Film 01 Film 02 Film 03 Film 04 Gap Filler 01 Gap Filler 02 Gap Filler 03 Gap Filler 04 Gap Filler 05 Gap Filler 06 Gap Filler 07 Gap Filler 08 Gap Filler 09 Gap Filler 10 Gap Filler 11 Grease 01 Grease 02 Grease 03 Pad 01 [W/mK] TIMA vs datasheets 8 6,5 6,0 5,5 5,0 4,5 4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0,0 Bulk eff Datasheet

9 Our solutions for reliable material data (2) LaTIMA 9 TIMA LaTIMA TIMAwave Steady state measurement Steady state measurement Transient measurement Measurement of bulk thermal conductivity of low and middle thermally conductive materials Measurement of thermal interface resistance IR-Camera For solid and viscus LaTIMA materials Measurement of bulk thermal conductivity of middle and high thermally conductive materials For solid materials Substrate (e.g. FR4, IMS, LTCC, HTCC, ) TIM (e.g. adhesive, grease, Tempgap filler, films, ) sensors IsolationHeat layers Temp flow senso TE cooler rs sensors Heater Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys In-plane measurement Measurement of thermal diffusivity of all solid materials from low to highly conductive For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys

10 2 nd reference body 2 nd reference body 1 st reference body Heat flow Q The development history (TIMA LaTIMA ) 10 TIMA Thermal Interface Materials Analyzer: Thermal conductivity measurement of low to middle thermally conductive materials LaTIMA Lateral Thermal Interface Materials Analyzer: In-plane thermal conductivity measurement of high thermally conductive materials ΔT Heater T1 T2 T3 1 st reference body T4 T5 Sample ΔT T4 T5 IR ΔT L Heat flow Q Rth sample T3 T2 T Q Sample sample sample T6 Cooler T6 Cooler T1 Heater

11 LaTIMA Lateral Thermal Interface Materials Analyzer LaTIMA is an innovative test stand for precision measurement of lateral thermal and electrical conductivity of highly conductive materials such as:» Metals» Substrates» Solders» Sintered materials» Semiconductors» and much more Temperature sensor Heat flow sensor 11 The innovative idea of LaTIMA is to increase the temperature gradients over the sample by enlarge the heat path. measurement of highly thermal conductive materials

12 Th. conductivity [W/mK] Verification and benchmark of LaTIMA Measured values Literature values Al 99.5 CuZn 37 E-Cu Ag 99.9 AlN Pb95Sn5 Sn60Pb38 SAC

13 Th. conductivity [W/mK] Processing-Structure-Property Correlations of Sintered Silver 13 Samples preparation, variation of sinter parameters Measurement of thermal conductivity by LaTIMA Thermal conductivities as function of sintering parameters sample, L=20mm, W=5mm, T=50µm Th. conductivity [W/mK] 220 T=200 C (constant) T=225 C (constant) 200 T=250 C (constant) T=270 C (constant) Thermal conductivity as function of porosity Sintering Pressure [MPa] Structure analysis by FIB and SEM Porosity [%]

14 Our solutions for reliable material data - (3) TIMAwave 14 TIMA LaTIMA TIMAwave Steady state measurement Steady state measurement Transient measurement Measurement of bulk thermal conductivity of low and middle thermally conductive materials Measurement of thermal interface resistance For solid and viscus materials Measurement of bulk thermal conductivity of middle and high thermally conductive materials For solid materials Substrate (e.g. FR4, IMS, LTCC, HTCC, ) TIM (e.g. adhesive, grease, gap filler, films, ) Isolation layers Substrate (e.g. AlN, Al2O3, TIMAwave Si3N4, IR-Camera ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Laser Metals and alloys diode heater TE cooler Sample holder Measurement of thermal diffusivity of all solid materials from low to highly conductive For solid materials Substrate (e.g. AlN, Al2O3, Si3N4, ) Die attach (e.g. solder, sinter Ag, sinter Cu, ) Metals and alloys In-plane measurement

15 Log Amplitude [K] Phase [rad] T / C T [ C] Methodology (Angström s method) 15 1 Modulated heating X time / s t [s] T 1D damped thermal wave along the heat path k x x, t A e cos t k x T= constant α: Thermal diffusivity ω: Excitation frequency k: thermal wave number k k 2 2 k 2 k X X

16 Amplitude [K] Diffusivity [mm²/s] Phase Amplitude Amplitude [K] Phase Slope [1/m] Phase [rad] Amplitude Phase [rad] Proof of Concept by FE simulation 16 Cooling (T=const) Modulated heat input AMP [K] High deviation of the results of amplitude due to: Insufficient modeled number of excitation period (no static oscillation regime) Heat losses by convection and radiation may have more impact on the amplitude FE model has been generated Transient thermal simulation results in: Different frequencies different slops (as expected) Expected thermal diffusivity values fit well with the extracted values from the phase information but not from the amplitude Hz 10 Hz Hz 10 Hz X [m] k 2 2 k Overview on simulation results compared to expected diffusivity from the simulation input material data f [Hz] Expected values Calculated values Deviatio n % % % % % 0.1 Results from simulations. Different linear slopes for different frequencies % % %

17 Log Amplitude or Phase Cooler block T [K] Thermal isolated sample holder T [ C] The development history (LaTIMA TIMAwave ) NEW 17 Modulated heating Phase image Output of active lock- in thermography IR t [s] Amplitude image Sample X X X k Cooler T 1D damped thermal wave along the heat path k x x, t A e cos t k x X 2 k 2

18 LaTIMA and TIMAwave in one test stand 18 LaTIMA IR-Camera Temp sensors TIMAwave TE cooler Heat flow senso rs IR-Camera Temp sensors Heater Laser diode heater IR- Camera Laser diode heater TE cooler Sample holder TE cooler Heater

19 Characterization of bulk metals 19 Thermal conductivity [W/mK] Cu CuZn Ag Al LaTIMA TIMAwave 5 mm Ag99.9 Al95.5 Cu-HCP CuZn37 cp Material Silver (Ag99.9) Aluminium (Al99.5) Copper (Cu HCP) Brass (CuZn37) Themal diffusivity [mm²/s] α (TIMA wave) [mm²/s] ,6 Thermal diffusivity ,3 Ag99.9 Al95.5 Cu-HCP CuZn37 ρ (Lit) [kg/m³] Cp (Lit) [J/kg*K] λ (TIMA wave) [W/mK] λ (LaTIMA) [W/mK] 167± ±15 429±20 88± ±21 230±11 105± ±25 377±20 31± ±8 120±7 Both the measured thermal diffusivity and the calculated thermal conductivity fit well with the literature values as well as to measured values by LaTIMA

20 Thermal conductivity [W/mK] Characterization of bulk ceramics mm 180 Thermal conductivity cp Thermal diffusivity [mm²/s] Thermal diffusivity 68,7 34,4 7,20 Al2O3 AlN Si3N , ,6 Al2O3 AlN Si3N4 Material α [mm²/s] Cp (Lit) [J/kg*K] ρ (Lit) [kg/m³] λ [W/mK] Al 2 O 3 7.2± ±0.8 AlN 68.7± ±6 Si 3 N ± ±7 Both the measured thermal diffusivity and the calculated thermal conductivity fit well with the literature values

21 Summary 21 Different material types are used in electronic packages Different types of test methods are needed Datasheet should not be trusted Material parameters in real application can vary from the bulk values of the same materials Three test stands for thermal characterization of broad range of material types have been presented» TIMA for cross-plane thermal conductivity measurement of low and middle thermally conducive materials» LaTIMA for in-plane thermal conductivity measurement of middle and high thermally conducive materials» TIMAwave for in-plane thermal diffusivity measurement

22 22 Thank you for your attention! Contact: Mohamad ABO RAS Tel.: