Integrated thick-film hybrid microelectronics applied on different material substrates C. Jacq, T. Maeder, S. Menot-Vionnet, I. Saglini, H. Birol, and P. Ryser EPFL - LPM Lausanne, Switzerland lpmwww.epfl.ch June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 1
Objective low temperature High temperature thick-film system thick-film system Resistor Conductor Conductor Dielectric Substrate June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 2
Issues with low-temperature thick-films � Compatibility of thermal expansion � Dielectric-resistor compatibility � Adhesion � Stability of the resulting circuits June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 3
3 Temperature Ranges System Firing Temperature 500…550°C 575…650°C 850°C Dielectrics & Resistor Dielectrics Based on V8 glass Based on V6 glass Commercial dielectrics & Du 2041 resistor 85% PbO + 10% B 2 O 3 75% PbO + 10% B 2 O 3 + 5% SiO 2 + 2% Al 2 O 3 + 15% SiO 2 + 2% Al 2 O 3 & ESL 3114 Resistor Aluminium austenitic Alumina Alloys & & & ferritic steels Austenitic & ferritic AlSi composites steels June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 4
TCE of tested Substrates Alumina AlSi CE 9 (osprey Metal) AlSi CE 11 (Osprey Metal) Ferritic steel 1.4016 Austenitic steel 1.4435 AlSi CE 17 (Osprey Metal) Aluminium EN AW 6060 0 10 20 30 (ppm/K) June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 5
Studied dielectric compositions Deno- glass Filler Grain % filler T f (°C) TCE Substrate Size ( µ mination powder (ppm/K) screen-printed m) V8A40 V8 Al 2 O 3 ~1 40 ~500 ~9 - Aluminium - AlSi composites V8Q40 V8 quartz ~3 40 ~500 ~12 - Aluminium Cristo- 10…20 - Aluminium V8C40 V8 40 ~500 ~13 balite Al 2 O 3 40 . Steels V6A40 V6 ~1 ~600 ~8 - Steels V6Q50 V6 quartz ~3 50 ~600 ~10-11 (ESL - - - - 850 ~7-8 - Alumina 4916) - Steels +Her GPA - Alumina (ESL - - - - 850 ~7-8 4916) - Steels +ESL 4924 June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 6
Dielectrics & resistor Compositions Dielectric composition Resistor composition -400 nm -Firing temperature 500°C June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 7
Paste preparation Mixing powder SiO 2 , B 2 O 3 , PbO, Al 2 O 3 melting Al 2 O 3 or SiO 2 Milling, sieving of powder glass powder Mixing glass powder Organic vehicle –filler powder Mixing in the tri-cylinder Dielectric paste June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 8
Screen-printing sequence Basic Resistor Conductor Conductor structure 40 µ m Dielectric Substrate June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 9
Samples for characterisation � Gauge Factor measurement � TCR measurement Longitudinal resistors Transverse resistors June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 10
Adhesion & Crack problems � Crack problems � Adhesion Non adherence on non-oxidised substrates Match TCE Oxidation 1h @ 900°C June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 11
Dissolution of SiO 2 powder in glass SiO 2 particles & low-temp. glass glass + SiO 2 SiO 2 - rich glass � Effect on resistors… V8 glass V6 glass Dissolution 600 °C 625°C Temperature of SiO 2 (10% filled) June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 12
Results: Aluminium alloy Substrates Low Temperature range 50 200'000 180'000 0 Sheet resistance [Ohm] 160'000 -50 HTCR [ppm/K] 140'000 120'000 -100 100'000 -150 80'000 -200 60'000 40'000 -250 20'000 -300 0 450 475 500 525 550 575 600 450 500 550 600 Dielectric Firing Temperature [C] Dielectric Firing Temperature [C] V8 glass + 40% cristobalite V8 glass + 40% quartz V8 glass + 50% cristobalite V8 glass + 50% quartz June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 13
Results: AlSi composite Substrates Low Temperature range 120'000 200 Sheet resistance [Ohm] HTCR [ppm/K] 100'000 100 80'000 0 60'000 -100 40'000 -200 20'000 -300 0 500 525 550 480 500 520 540 560 Dielectric Firing Temperature [C] Dielectric Firing Temperature [C] AlSi CE 9 AlSi CE 11 AlSi CE 17 June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 14
Results: Steel Substrates Low Temperature range 160'000 0 140'000 Sheet Resistance HTCR (ppm/K) -50 120'000 (Ohms) 100'000 -100 80'000 60'000 -150 40'000 20'000 -200 0 500 525 550 500 525 550 Firing Temperature (°C) Firing Temperature (°C) Alumina V8 glass + 40% alumina on 1.4016 V8 glass + 40% alumina on 1.4435 V8 glass + 40% quartz on 1.4016 V8 glass + 40% quartz on 1.4435 June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 15
Results: Steel Substrates Intermediate Temperature range 45000 75 600°C 40000 Sheet Resistance 575°C 25 35000 TCR (ppm/K) 30000 -25 (Ohms) 25000 -75 20000 15000 -125 575°C 10000 -175 5000 575°C -225 0 Dielectric Firing Temperature (°C) Dielectric Firing Temperature (°C) Alumina V6 glass + 40% alumina on 1.4016 V6 glass + 40% alumina on 1.4435 V6 glass + 50% quartz on 1.4016 V6 glass + 50% quartz on 1.4435 June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 16
Results: Steel Substrates High Temperature range Dielectric 4924 GPA 98-029 Alumina (alumina) 1.4016 850°C 1.4435 850°C 0 5000 10000 15000 20000 25000 Sheet resistance (Ohms) Dielectric 4924 GPA 98-029 (alumina) 0 50 100 150 200 250 300 TCR (ppm/K) June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 17
Electrical results Insulting Dielectric Substrate Resistor System Sheet TCR GF Dielectric TCE paste Firing resistance (ppm/K) (ppm/K) Temp.(°C) (kOhms) V8A40 9 AlSi comp. CE 9 V8 500 22.7 -79 - Resistor AlSi comp. CE 11 23.9 -104 - Aluminium 23.4 -27 - 13 525 V8C40 12 Aluminium 525 19.3 -47 6 V8Q40 1.4016 550 28.6 -145 - 1.4435 25.9 -41 - 8 1.4016 ESL 575 26.1 -124 - V6A40 3114 1.4435 34.5 73 - 10-11 1.4016 600 24.9 -178 - V6Q50 1.4435 39.8 53 - ~7-8 Alumina Du 2041 850 14.6 39 12.4 Her GPA (+ ESL 4916 as 1.4016 17.6 104 10.6 under-layer on 1.4435 20.7 218 - steel) ~7-8 Alumina 19.9 38 ESL 4924 (+ ESL 4916 as 1.4016 19.3 136 9.9 under-layer on 1.4435 22.2 243 12.1 steel) June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 18
Gauge factor results Similar gauge factors Al - V8A40 550°C Al - V8A40 525°C Al - V8Q40 500°C Transverse 1.4435 - V8A40 550°C Longitudinal s 1.4435 - V8A40 525°C c i 1.4435 - V8Q40 500°C r t c 1.4435 - V8A40 525°C e l e 1.4016 - V8A40 550°C i D 1.4016 - V8A40 525°C 1.4016 - V8Q40 500°C 1.4016 - V8A40 525°C Alumina 0 2 4 6 8 10 G a u g e F a c t o r June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 19
Conclusions � Dielectric – resistor chemical compatibility � Very low processing temperature achieved � Compatible with wide range of substrates � Matching of thermal expansion is critical June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 20
CTE range: glass + SiO 2 Little reaction : very wide range of CTE values possible • due to different forms of SiO 2 Fully reacted : OK for alumina, float glass & Ti • June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 21
Outlook � Fillers: improve stability and reproducibility of dielectrics � Control of TCR of our resistors through additives (CuO, NiO, TiO 2 , Sb 2 O 3 ) � Materials without Pb or precious metals June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 22
Explanation 1 � TCR = (GF L + GF T ) x �� June 14, 2005 EMPS - IMAPS – BRUGGE - 2005 page : 23
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