Consolidated Thermal & Mechanical Materials Table (Microelectronics)
Metals and Alloys
| Material | k | CTE | Density | Modulus | Electrical Conductivity | Cost | Typical Use |
|---|
| Copper (OFHC) | 390–400 | 16–17 | 8.9 | 110–130 | ~100% IACS | Med | Heat spreaders, baseplates, leadframes |
| Aluminum (6061) | ~170 | 23–24 | 2.7 | ~69 | ~40–60% IACS | Low | Heatsinks, housings |
| Molybdenum | 130–140 | ~5 | 10.2 | ~320 | Low | High | Low-CTE package bases, carriers |
| Tungsten | 170–175 | ~4.5 | 19.3 | ~400 | Low | High | Dense spreaders, hermetic bases |
| Invar 36 | 10–15 | 1–2 | 8.1 | ~140 | Low | High | Precision frames, matched structures |
| Alloy 42 | 14–17 | 4–5 | 8.1 | ~150 | Low | Med–High | Leadframes, glass-seal packages |
| Kovar | 16–19 | 5–6 | 8.3 | ~140 | Low | High | Hermetic packages, glass-to-metal seals |
Copper–Molybdenum (Cu-Mo) Composites
| Material | k | CTE | Density | Modulus | Electrical Conductivity | Cost | Typical Use |
|---|
| 85Mo/15Cu | ~148 | ~7.6 | ~10 | High (~250–300 est.) | Moderate | High | Low-CTE spreaders, RF packages |
| 70Mo/30Cu | ~195 | ~7.5 | ~9.8 | High | Moderate | High | General package bases |
| 65Mo/35Cu | ~210 | ~7.8 | ~9.7 | High | Moderate | High | Alumina-matched packages |
| 60Mo/40Cu | ~220 | ~8.2 | ~9.6 | High | Moderate | High | Heat spreaders, stress buffers |
| 75Mo/25Cu | ~170–190 | ~7 | ~10 | High | Moderate | High | Low-CTE carrier |
Copper–Tungsten (Cu-W) Composites
| Material | k | CTE | Density | Modulus | Electrical Conductivity | Cost | Typical Use |
|---|
| WCu 70/30 | ~190–210 | ~9–10 | ~14.3 | Very high | Moderate | High | Heat spreaders |
| WCu 75/25 | ~180–190 | ~9 | ~15 | Very high | Moderate | High | General package bases |
| WCu 80/20 | ~170–180 | ~8.2 | ~15.7 | Very high | Moderate | High | Chip carriers |
| WCu 85/15 | ~160 | ~7.5–8 | ~16.5 | Very high | Moderate | High | Hermetic bases |
| WCu 90/10 | ~150 | ~7 | ~17.3 | Very high | Moderate | High | Low-CTE submounts |
Laminates & Substrates
| Material | k | CTE | Density | Modulus | Electrical Conductivity | Cost | Typical Use |
|---|
| Alumina (Al₂O₃) | 20–30 | ~6–8 | ~3.9 | ~300 | Insulator | Med | Hybrid circuits, substrates |
| AlN | 90–230 | ~4–5 | ~3.3 | ~310 | Insulator | High | High-power substrates |
CMC / CPC / Laminate Metal Substrates
| Material | k | CTE | Density | Modulus | Electrical Conductivity | Cost | Typical Use |
|---|
| CMC 111 (Cu/Mo/Cu) | ~250 | ~8.3 | ~9.3 | High | High (Cu skins) | High | Heat spreaders, RF packages |
| CMC 121 | ~210 | ~7.8 | ~9.5 | High | High | High | Balanced submounts |
| CMC 131 | ~190 | ~6.8 | ~9.7 | High | High | High | Low-CTE carriers |
| CMC 141 | ~180 | ~6.0 | ~9.8 | High | High | High | Ceramic-matched bases |
| CMC low-CTE (13/74/13) | ~170 | ~5.6 | ~9.9 | High | High | High | Si/AlN matched structures |
| CPC 141 (Cu/MoCu/Cu) | ~220 | ~8.4 | ~9.5 | High | High | High | Package bases |
| CPC 232 | ~255 | ~9 | ~9.3 | High | High | High | High spreading laminate |
| CPC 111 | ~260 | ~9.5 | ~9.2 | High | High | High | Submounts |
| CPC 212 | ~300 | ~11.5 | ~9.1 | High | High | High | Max heat spreading, higher mismatch |
Key Engineering Takeaways
- Highest thermal conductivity: Copper, CPC laminates, high-Cu CMC
- Best CTE match to Si (~2.6–4 ppm/°C): Mo, W, AlN, low-Cu CMC, Cu-W high-W grades
- Best compromise (thermal + CTE): Cu-Mo, CMC 131–141
- Best electrical + thermal laminate: CPC / CMC (due to copper outer layers)
- Lowest cost system: FR-4 + aluminum heatsink + grease
- Highest stability / hermetic systems: Kovar, Cu-W, Mo