Coaxial Thermal Converter

1
Coaxial Thermal Converter
100 series connected thermocouples
EvanOhm heater
Membrane Boundary
Silicon obelisk
Au
Si (Substrate)
SiN
Cross section of chip
Thermocouple
Heater
Si (Obelisk)
2
HARSE/Bosch Etching

• SF6/Ar reactive ion etching alternating with
  fluorocarbon conformal passivation to prevent
  sidewall etching
• High-aspect ratio 201
• High Si etch rate 3 mm/min
• Good selectivity to photoresist (501) and other
  materials
• Compatibility with standard processes like CMOS

2) SF6 /Ar Etch
1) Passivation
Silicon Substrate
3
Fabricated TVC Die

• EvanOhm heater for TVC (200 W to 1000 W)
• Gold heater for TCC (0.1 W to 5 W)
• Examining new designs for high current

Heater
Thermocouples
Membrane Boundary
4
ObeliskFormation
Frontside View
50 mm
Si Obelisk Boundary
Thermocouples
Heater
Inner Substrate Edge
Backside View
5
100 mm Wafer
6
LF10b Bifilar FMJTC
Bonding Pads
Thermocouples
Heater
Membrane Boundary
Obelisk
7
LF10c Coaxial FMJTC
Bonding Pads
Thermocouples
Heater
Membrane Boundary
Obelisk
8
Solid Modeling and Automatic Meshing CUBIT
SJTC
FMJTC
Journal Files Simplify Changes in Geometry
9
Steady State Simulation Result for Two Heater
Styles

• Simulation shows membrane region. Simulation is
  3D, obelisk extends into the page beneath heater
• Low-frequency performance improved through
  elimination of residual heating effect in region
  between obelisk and substrate edges
• No additional mask layer (as in compensation
  technique)