MEMS FABRICATION

Packaging Facility

Assembly Facility

LTCC

FABRICATION PRODUCTION

Micro-Electro-Mechanical System (MEMS) Process & Fabrication Facility

State of art MEMS fabrication facility for processing silicon 6-inch wafer with 1um feature size has been established.

  1. Major process: Bulk Micromachining and Surface Micromachining
  2. Wafers used: Bulk Si wafers, EPI wafers, SOI wafers, Quartz wafers, Glass wafers.

Key process & Equipment’s

  1. Photolithography:
    • Mask aligner & Wafer track system for patterning. Front to Back alignment verification tools
  2. Etching (Dry etch & Wet etch):
    • Deep Reactive Ion Etching (DRIE) for Silicon and Silicon dioxide/Silicon nitride for dry etching
    • KOH & TMAH for wet anisotropic etching
    • Vapor phase etching (VPE ) system for release of MEMS structures and Carbon dioxide Critical Point Drying (CPD)
  3. Metallization:
    • Metallization for Contact holes and metal lines.
    • Metals used for interconnection: Aluminium (Sputtering), Gold (E-beam), Titanium, Chromium, Platinum
  4. Diffusion & CVD:
    • PECVD system for Dielectric layer deposition (SiO2, Si3N4)
    • LPCVD system for Silicon Nitride layer deposition
    • Atmospheric furnace for dry & wet oxidation
    • Atmospheric furnace for alloying with N2 & H2 environment
    • Atmospheric furnace for annealing in N2 environment.
    • P-type doping using diffusion furnace at the range of 1019 dopant/cc up to 12um depth.
  5. Planarization:
    • Chemical Mechanical Polishing (CMP) system for planarization of dielectric, metal & poly silicon layers.
  6. Wafer Bonding:
    • Wafer bonding equipment for Si-Si fusion bonding (3 wafers) and Si-glass anodic bonding.
  7. Characterization Tools:
    • Optical profiler – Step height measurement
    • FESEM, EDAX & FIB – Topography imaging, Composition analysis and Cross section measurement.
    • Ellipsometer – Dielectric film Thickness measurement
    • Cascade Prober & Key sight Tester – DC parameter measurement
    • Polytec Motion Analyser – Resonance frequency and displacement of Released MEMS devices
    • Metal thickness & Resistivity measurement system

MEMS FABRICATION

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Packaging Facility

Processed 6” wafers with 1µm feature size processed dies comes to A&P dept. for assembling in suitable package for easy functional and environmental testing

  1. Major process: The processed dies are to be packaged in customized packages or in open tool packages or as per customer ordered packages.
  2. Packages used: Ceramic packages, Metal TO circular & rectangular packages, DIP packages, LCC packages, SoIC packages, PGA packages etc. Sometimes SIP (System In Package) also used for integration of MEMS sensor, ROIC and other associated dies / plastic packages.

Assembly department has the following common & Associated equipment’s:

  1. Grinding & Polishing Machine:
    • Mask aligner & Wafer track system for patterning. Front to Back alignment verification tools
  2. Mounting Machine:
    • This machine can mount up to 8” wafers on SS frames.
  3. Dicing Machine:
    • Two type of equipment’s are available. In one normal dicing can be carried out on all Ceramics, PCB, Glass & Si wafers, bonded wafers up to thickness 2500 to 3000 µms, Sapphire, MCT, PZT, GaAs, GaN, Molded QFN packages, Glass-glass bonded wafers, GaSb, Quartz wafers etc.
    • In one more type both circular and normal dicing above said operations can be carried out.
  4. Curing System:
    • After Dicing process dies are segregated on UV tape by applying UV light on tape.
  5. Die Attach & curing System:
    • This machine is used for making die to place firmly on package or any substrate either by using Insulative or Conductive Epoxies. Die attach Packages with Epoxies are cured in oven.
  6. Wire Bonding Machine:
    • This machine is used to make interconnect between sensor die and package pins to enable communication to the rest of devices in a PCB board or a control board. Al, Au, Pt of wire sizes 0.7 to 3 mil are used.
  7. Sealing Furnace:
    • Ceramic packages are sealed by conveyor method under N2 environment. Metal packages are sealed by Resistive welding. Integrated sensor die packages are sealed by custom designed metal lid and PCB mounted sensors with custom designed 3D ABS packages. Some packages are sealed by Vaccum method as per customer requirement.

Apart from the above common equipment’s, Associated list are underneath:

  1. Plasma Cleaning System: This machine is used prior to wire bonding for cleaning of die pads and substrate pins by plasma method.
  2. CMP Machine: Processed wafers having layers deposited in small thickness, can be mechanically polished with help of slurries to desired process thickness.
  3. Vaccum System: Fully assembled IR devices are subjected to ultra-vacuum conditions up to 10 e-10 Torr for a period of 15 days.
  4. GTM Oven: Glass to Metal sealing is carried out on customized metal Packages for prototype purpose.
  5. Lapping & Polishing Machine: In this machine certain samples like MCT, InSb, InGaAs substrates can be lapped & polished to required thickness.
  6. Non-Contact Thickness: This system helps to measures the thickness of wafers prior & after carrying out lapping & polishing process.
  7. Can & Seam Sealing Machine: In this machine circular and rectangular metal packages are sealed by Resistive welding method.
  8. Gas Booster Machine: This machine helps us to test JT coolers.
  9. Substrate Bonder: This bonder is used to mount samples like MCT, InSb, InGaAs substrates etc to a glass holder for lapping & polishing purpose.

Assembly Facility

Processed 6” wafers with 1µm feature size processed dies comes to A&P dept. for assembling in suitable package for easy functional and environmental testing

  1. Major process: The processed dies are to be packaged in customized packages or in open tool packages or as per customer ordered packages.
  2. Packages used: Ceramic packages, Metal TO circular & rectangular packages, DIP packages, LCC packages, SoIC packages, PGA packages etc. Sometimes SIP (System In Package) also used for integration of MEMS sensor, ROIC and other associated dies / plastic packages.

Assembly department has the following common & Associated equipment’s:

  1. Grinding & Polishing Machine:
    • Mask aligner & Wafer track system for patterning. Front to Back alignment verification tools
  2. Mounting Machine:
    • This machine can mount up to 8” wafers on SS frames.
  3. Dicing Machine:
    • Two type of equipment’s are available. In one normal dicing can be carried out on all Ceramics, PCB, Glass & Si wafers, bonded wafers up to thickness 2500 to 3000 µms, Sapphire, MCT, PZT, GaAs, GaN, Molded QFN packages, Glass-glass bonded wafers, GaSb, Quartz wafers etc.
    • In one more type both circular and normal dicing above said operations can be carried out.
  4. Curing System:
    • After Dicing process dies are segregated on UV tape by applying UV light on tape.
  5. Die Attach & curing System:
    • This machine is used for making die to place firmly on package or any substrate either by using Insulative or Conductive Epoxies. Die attach Packages with Epoxies are cured in oven.
  6. Wire Bonding Machine:
    • This machine is used to make interconnect between sensor die and package pins to enable communication to the rest of devices in a PCB board or a control board. Al, Au, Pt of wire sizes 0.7 to 3 mil are used.
  7. Sealing Furnace:
    • Ceramic packages are sealed by conveyor method under N2 environment. Metal packages are sealed by Resistive welding. Integrated sensor die packages are sealed by custom designed metal lid and PCB mounted sensors with custom designed 3D ABS packages. Some packages are sealed by Vaccum method as per customer requirement.

Apart from the above common equipment’s, Associated list are underneath:

  1. Plasma Cleaning System: This machine is used prior to wire bonding for cleaning of die pads and substrate pins by plasma method.
  2. CMP Machine: Processed wafers having layers deposited in small thickness, can be mechanically polished with help of slurries to desired process thickness.
  3. Vaccum System: Fully assembled IR devices are subjected to ultra-vacuum conditions up to 10 e-10 Torr for a period of 15 days.
  4. GTM Oven: Glass to Metal sealing is carried out on customized metal Packages for prototype purpose.
  5. Lapping & Polishing Machine: In this machine certain samples like MCT, InSb, InGaAs substrates can be lapped & polished to required thickness.
  6. Non-Contact Thickness: This system helps to measures the thickness of wafers prior & after carrying out lapping & polishing process.
  7. Can & Seam Sealing Machine: In this machine circular and rectangular metal packages are sealed by Resistive welding method.
  8. Gas Booster Machine: This machine helps us to test JT coolers.
  9. Substrate Bonder: This bonder is used to mount samples like MCT, InSb, InGaAs substrates etc to a glass holder for lapping & polishing purpose.

LTCC

State of the art fabrication facility for processing 8-inch X 8 inch ceramic substrates using Low Temperature Co-fired Ceramic (LTCC) technology has been established at STARC Bangalore for packages of MEMS Sensors and other Devices. Major process includes: Via punching, Via filling, Conductor Printing, Automated Vision Inspection, Automated Stacking, Iso static lamination, Semi automated green sheet cutting, Programmable control Co firing, Dicing.

Fabrication process is optimised for FERRO make green tapes and pastes. The process design rules are framed keeping in view of the process capability and unit process developed at STARC fabrication facility as on date.

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