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Photolithography

Reynard can customize patterns with geometries below 5 microns using our highly accurate photolithography process.  The process defines a masking area using photoresist on the substrate that will be void of any deposited coating material.  Unmasked areas will be fully coated.  After the vacuum deposition process, the mask areas are lifted-off, leaving behind only a precision coated pattern.  If multiple patterns are required, an alignment step is used to accurately place the next mask, and the process is repeated, typically with a different coating stack.

Photolithography patterns can be applied to any vacuum compatible substrate material, including glass, particular plastics, and ceramics.  Conductive patterns utilize ITO (Indium-Tin-Oxide) or a variety of metals, including chrome, gold, silver, aluminum, etc.  Dielectric patterns are used for filtering, splitting, or anti-reflection techniques and include materials such as SiO2, TiO2, Al2O3, etc.  Masks can be applied to substrates as large as 14" in diameter. 

Photolithographic patterns are used for such applications as: optical targets, reticles, alignment and resolution patterns, Quality Control patterns, encoder disks, pin holes, optical slits, angle measuring devices, and comparison filters. 

Examples of some filters we have produced are shown below:

Circular Variable Comb Filter   Environmental Sensors
Photolithography Process - Reynard Corporation   Photolithography Process - Reynard Corporation
 

This filter is used for non-imaging applications when in close proximity to a high-power light source. The filter varies the amount of radiation transmitted depending on the angular rotation. The constant coating thickness eliminates the bleaching effect seen when metal coatings are too thin on standard CVND filters.  Line width and spacing can be fully customized.

                

Patterns in varying sizes and materials can be placed on a single substrate.  Instruments can then identify the presence of particular elements or can monitor rates of decay in caustic environments as the patterns are affected by the environmental conditions in which they are placed.

     
 Alignment Test Pattern   Multi-Spectral Detector Filters
 Photolithography    Photolithography
 Test patterns are arrays of dots, lines, and references of varying sizes creating reticles or other shapes used to align or validate instrumentation performance.  Coatings tend to have a high optical density (OD4 or greater) to block out stray light, allowing light only through the defined areas.  Open areas can be enhanced with anti-reflection, or other types of filter coatings.    Several precision filters can be placed on a single, monolithic substrate in patterns such as lines or Bayer patterns.  These filters are used in front of detector arrays for multi-spectral sensing.  When multiple filters are implemented using our gapless photolithography technique, edge diffraction patterns are greatly reduced or even eliminated.  For small pattern requirements, larger test pads can be added  (as seen in image above) to allow for easy spectral performance testing of the deposited filters.