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.
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, Pd, Pt, Ta, Ti, V, W |
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)
