Thin film coating


LEW Techniques offers a subcontract service for the vacuum coating of components with thin films. For demanding applications thin films of metals can be sputtered or evaporated onto metals, ceramics, or other difficult-to-coat surfaces. These coatings can provide conductive and solderable layers on non-conductive materials or barriers and protective finishes on difficult-to-plate metals. Our manufacturing know-how and dedicated in-house facilities allows us to offer a comprehensive and versatile service.


Capability outline


    • Deposition by vacuum sputtering or evaporation
    • Various component substrate materials including ceramics, metals and glass
    • Coating schemes suitable for soldering, wire-bonding and protective finishes
    • Fine line pattern imaging by photolithography
    • Pattern realisation by wet chemical and plasma etching
    • Deposition through holes, around edges and on side walls
    • Global or selective deposition of gold/tin (AuSn) solder

Applications


    • Semiconductor heatsinks/mounts
    • Filters/windows/displays
    • Conductors/terminations
    • Medical implements
    • Reflectors/mirrors
    • Earth shields/grounding planes

Facilities


Housed in a class 10,000 clean room, our thin film facilities include:

  • Up and down sputtering tools with three- or four-source magnetron sputter targets
  • E-beam evaporators with four-source indexing crucibles
  • RIE and plasma cleaner/etchers

Complementary capabilities


    • Laser drilling, profiling and marking
    • Diamond sawing
    • Electroplating
    • Assembly by atmosphere brazing, soldering and welding
    • Comprehensive testing facilities to ensure product quality

Component materials


    • Ceramics including alumina, aluminium nitride and silicon carbide
    • Glasses including borosilicate and soda lime
    • Fused quartz, sapphire and ferrites
    • Semiconductor wafers including silicon and gallium arsenide
    • Metals including copper, kovar, tungsten/copper

Component geometry limits


  • Maximum length and width: 200 mm x 200 mm
  • Maximum diameter: 200 mm
  • Maximum thickness/height: 50 mm

Coatings


Depending on the equipment and coating types required up to four different coatings can be sequentially deposited in each coating run.


Typical coating layers include:
Adhesion Ti, Cr, NiCr, TiW, TaN
Barrier Pd, Pt, Ni
Conductor Cu, Au
Solder AuSn
Typical coating schemes include:
Cr/Au For decorative/reflective finish
TiW/Pd/Au For SnPb, SnAg soldering
TiW/Pd/Au/Ni/Au For additional soldering leach resistance
Ti/Pt/Au Best soldering performance but more costly
NiCr For protective finish
For high conductivity For high conductivity
AuSn Solder pre-deposition for critical attach
Typical deposition thickness:
Adhesion layers 100 – 2000 Å (angstroms)
Barrier layers 0.1 – 2 μm
Conductors 0.2 – 5 μm

Masking


By using physical masks the coatings can be selectively deposited onto required areas only.


High resolution patterning


Utilising wet or dry film photo resists, fine high density lines and features can be resolved to create circuits, logos and other images.


Microcircuits


Contact us for details of our comprehensive capabilities for manufacturing RF and optoelectronic microcircuits.