Integrated thick-film hybrid microelectronics applied on different material substrates

Transcription

1 Integrated thickfilm hybrid microelectronics applied on different material substrates C. Jacq, T. Maeder, S. MenotVionnet, I. Saglini, H. Birol, and P. Ryser EPFL LPM Lausanne, Switzerland lpmwww.epfl.ch page : 1

2 Objective High temperature thickfilm system low temperature thickfilm system Conductor Resistor Dielectric Substrate Conductor page : 2

3 Issues with lowtemperature thickfilms! Compatibility of thermal expansion! Dielectricresistor compatibility! Adhesion! Stability of the resulting circuits page : 3

4 3 Temperature Ranges System Firing Temperature C C 850 C Dielectrics & Resistor Based on V8 glass 85% PbO + 10% B 2 O 3 + 5% SiO 2 + 2% Al 2 O 3 Dielectrics Based on V6 glass 75% PbO + 10% B 2 O % SiO 2 + 2% Al 2 O 3 & ESL 3114 Resistor Commercial dielectrics & Du 2041 resistor Aluminium Alloys & AlSi composites austenitic & ferritic steels Alumina & Austenitic & ferritic steels page : 4

5 TCE of tested Substrates Alumina AlSi CE 9 (osprey Metal) AlSi CE 11 (Osprey Metal) Ferritic steel Austenitic steel AlSi CE 17 (Osprey Metal) Aluminium EN AW (ppm/k) page : 5

6 Studied dielectric compositions Denomination glass Filler Grain Size (µ m) % filler powder T f ( C) TCE (ppm/k) Substrate screenprinted V8A40 V8 Al 2 O 3 ~1 40 ~500 ~9 Aluminium AlSi composites V8Q40 V8 quartz ~3 40 ~500 ~12 Aluminium V8C40 V8 Cristobalite ~500 ~13 Aluminium V6A40 V6 Al 2 O 3 ~1 40 ~600 ~8. Steels V6Q50 V6 quartz ~3 50 ~600 ~1011 Steels (ESL 4916) +Her GPA 850 ~78 Alumina Steels (ESL 4916) +ESL ~78 Alumina Steels page : 6

7 Dielectrics & resistor Compositions Dielectric composition Resistor composition 400 nm Firing temperature 500 C page : 7

8 Paste preparation Mixing powder SiO 2, B 2 O 3, PbO, Al 2 O 3 melting Milling, sieving of glass powder Al 2 O 3 or SiO 2 powder Organic vehicle Mixing glass powder filler powder Mixing in the tricylinder Dielectric paste page : 8

9 Screenprinting sequence Basic structure 40µm Conductor Resistor Dielectric Substrate Conductor page : 9

10 Samples for characterisation "TCR measurement "Gauge Factor measurement Longitudinal resistors Transverse resistors page : 10

11 Adhesion & Crack problems "Adhesion "Crack problems Non adherence on nonoxidised substrates Match TCE Oxidation 900 C page : 11

12 Dissolution of SiO 2 powder in glass SiO 2 particles & lowtemp. glass glass + SiO 2 SiO 2 rich glass V8 glass V6 glass! Effect on resistors Dissolution Temperature of SiO 2 (10% filled) 600 C 625 C page : 12

13 Results: Aluminium alloy Substrates Low Temperature range Sheet resistance [Ohm] 200' ' ' ' ' '000 80'000 60'000 40'000 20' Dielectric Firing Temperature [C] HTCR [ppm/k] Dielectric Firing Temperature [C] V8 glass + 40% cristobalite V8 glass + 40% quartz V8 glass + 50% cristobalite V8 glass + 50% quartz page : 13

14 Results: AlSi composite Substrates Low Temperature range Sheet resistance [Ohm] 120' '000 80'000 60'000 40'000 20' Dielectric Firing Temperature [C] HTCR [ppm/k] Dielectric Firing Temperature [C] AlSi CE 9 AlSi CE 11 AlSi CE 17 page : 14

15 Sheet Resistance (Ohms) 160' ' ' '000 80'000 60'000 40'000 20'000 Results: Steel Substrates Firing Temperature ( C) Low Temperature range HTCR (ppm/k) Alumina V8 glass + 40% alumina on V8 glass + 40% alumina on V8 glass + 40% quartz on V8 glass + 40% quartz on Firing Temperature ( C) page : 15

16 Results: Steel Substrates Intermediate Temperature range Sheet Resistance (Ohms) C 575 C Dielectric Firing Temperature ( C) TCR (ppm/k) C Dielectric Firing Temperature ( C) 575 C Alumina V6 glass + 40% alumina on V6 glass + 40% alumina on V6 glass + 50% quartz on V6 glass + 50% quartz on page : 16

17 Results: Steel Substrates High Temperature range Dielectric 4924 GPA (alumina) Dielectric Sheet resistance (Ohms) Alumina C C GPA (alumina) TCR (ppm/k) page : 17

18 Electrical results Insulting Dielectric Dielectric TCE (ppm/k) Substrate Resistor paste System Firing Temp.( C) Sheet resistance (kohms) TCR (ppm/k) GF V8A40 V8C AlSi comp. CE 9 AlSi comp. CE 11 Aluminium V8 Resistor V8Q40 12 Aluminium V6A40 V6Q ESL Her GPA (+ ESL 4916 as underlayer on steel) ESL 4924 (+ ESL 4916 as underlayer on steel) ~78 ~78 Alumina Alumina Du page : 18

19 Gauge factor results Similar gauge factors Dielectrics Al V8A C Al V8A C Al V8Q C V8A C V8A C V8Q C V8A C V8A C V8A C V8Q C V8A C Alumina Transverse Longitudinal Gauge Factor page : 19

20 Conclusions! Dielectric resistor chemical compatibility! Very low processing temperature achieved! Compatible with wide range of substrates! Matching of thermal expansion is critical page : 20

21 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 page : 21

22 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 page : 22

23 Explanation 1!TCR = (GF L + GF T ) x!" page : 23