Melting resist technology uses standard semiconductor processes and allows to fabricate microlenses from 5 µm to 5 mm diameter of excellent optical quality for wavelength from the DUV to the IR.

PHOTORESIST PROCESSING

• A thick layer of photoresist is coated onto a fused silica or silicon wafer.
  
• Resist cylinders is fabricated by photolithography and subsequent developing.
  
• The cylinders are melted in an oven or on a hot plate at about 150°C.
  

REACTIVE ION ETCHING

• The resist lenses are transferred in fused silica or Silicon by reactive ion etching (RIE).
  
• A precise control of the profile by changing the etch rate during the RIE step allows the fabrication of high quality spherical and aspherical microlenses.