Deposition

Micro and optoelectronic components and circuits consist not only of crystalline semiconductors. A variety of other material is required, e.g. metal contacts, traces, insulating layers and dielectric mirrors.

In order to deposit these materials in an appropriate way to the wafer, different procedures are carried out. These deposition techniques are ranging from physical vacuum evaporation and sputtering processes to chemical vapor deposition (PECVD) and wet-chemical electroplating.

Ion beam sputter tool
Ion beam sputter tool

Deposition of Insulators

Isolating layers are imperative components of solid-state devices and ICs. RF sputtering and plasma-enhanced chemical vapor deposition (PECVD) are the customary manufacturing processes. Both deposition methods are applied at the FBH with the corresponding equipment:

Equipment

Principle

Deposited isolating film

Ardenne
CS 730
Sputtering Ta2O5, Al2O3, SiO2, Si3N4
Sentech
SI 600 D
PECVD (parallel plate reaktor) SiNx
Sentech
SI 500 D
ICPECVD SiNx, SiOx, SiOxNy

Metallization

Metallic films are essential parts in solid-state devices and ICs, both as contacts and conductive stripes as well as passive elements like coils and capacitors. The films are deposited on the wafer by electron-beam evaporation or sputtering with the corresponding equipment:

Equipment

Principle

Used Materials

Leybold
560 HV
Electron beam evaporation Al, Au, Cr, Ge, Ni, Pd, Pt, Ti, V
Leybold
560 UHV
Electron beam evaporation Ti, Pt, Au, Ni
Balzers
PLS 570
Electron beam evaporation and sputtering Al, Ge, Mo, Pt, Ti, Au, Ni, Mo (evaporated), WSiN, Pt, Ir (sputtered)
Leybold
A 700
Electron beam evaporation Au, Sn, In
Ardenne
CS 730
Sputtering WSiN, AuGe, NiCr, Ni
Leybold
Z 590
Sputtering TiW, Au, ITO
Pfeiffer
Classic
Electron beam evaporation Au, Al, Ir, Mo, Ni, Pt, Ta, Ti, V

Electroplating

Gold has high electrical and thermal conductivity. It is chemically inert and does not corrode. Because of its many advantageous properties, gold is used for devices operating at high frequencies and with high power. Thick gold air bridges are often used for low resistive interconnects and efficient heat spreading.

Fields of application:

  • Low resistive interconnects with increased metal thickness (up to 20 µm)
  • Air bridge technology
  • Contact pads suitable for wire bonding
  • Interconnects for heat spreading
  • Alignment structures
  • Vias (vertical electrical interconnects)