Injection molded microoptics

Abstract

A wafer-scale apparatus and method is described for the automation of forming, aligning and attaching two-dimensional arrays of microoptic elements on semiconductor and other image display devices, backplanes, optoelectronic boards, and integrated optical systems. In an ordered fabrication sequence, a mold plate comprised of optically designed cavities is formed by reactive ion etching or alternative processes, optionally coated with a release material layer and filled with optically specified materials by an automated fluid-injection and defect-inspection subsystem. Optical alignment fiducials guide the disclosed transfer and attachment processes to achieve specified tolerances between the microoptic elements and corresponding optoelectronic devices and circuits. The present invention applies to spectral filters, waveguides, fiber-optic mode-transformers, diffraction gratings, refractive lenses, diffractive lens/Fresnel zone plates, reflectors, and to combinations of elements and devices, including microelectromechanical systems (MEMS) and liquid crystal device (LCD) matrices for adaptive, tunable elements. Preparation of interfacial layer properties and attachment process embodiments are taught.

1 - 19 . (canceled) 
     
     
         20 . Apparatus for the injection molding and aligned transfer of wafer-scale microoptic elements, the apparatus compressing:
 a template including at least one alignment key;   etching means for forming a patterned array of shaped cavities in the template;   a fill tool for scanning movement across the template, and including a plurality of dispensing heads interchangeable between scans for injecting one or more polymerizable materials into said cavities;   means for at least partially polymerizing said materials in said cavities to form injection molded microoptic elements in said cavities;   a target substrate;   an aligner tool for using said at least one alignment key to move said template into a defined position relative to said target substrate; and   a transfer tool for displacing the injection molded microoptic elements from the array of cavities onto the targeted substrate.   
     
     
         21 . Apparatus according to  claim 20 , further comprising:
 a tool for applying a release layer agent to the cavity surfaces to facilitate removing the molded microoptic elements from said cavities;   a crucible for providing a mixture of liquid materials, including said polymerizable materials, to the dispensing heads of the fill tool;   an inspection tool for inspecting the materials injected into the template cavities to confirm selected properties of said materials; and   a clamping fixture for securing said template to said substrate and maintaining a given alignment of said array of cavities and said substrate; and   wherein the means for at least partially polymerizing said materials in said cavities includes:
 i) means for solidifying the materials in said cavities in the template; and 
 ii) illumination means for providing ultraviolet light to control the degree of polymerization of the materials in said template cavities. 
   
     
     
         22 . Apparatus according to  claim 21 , further comprising:
 a template cleaning tool for removing from the template materials used to fill the array of cavities, to allow reuse of the template; and   a thermal reflow oven for applying controlled temperatures of the formed microoptic elements to enable shape adjustment and void/gap filling to effect a contiguous web of elements of the array on the substrate; and   wherein the transfer tool includes a fixture frame, contact points, a base and separating means.   
     
     
         23 . The apparatus of  claim 20 , wherein:
 the injection-mold template is a photoimagable material layer, overlaying a carrier substrate, such that a decal process for fast turnaround time template formation, is enabled.   
     
     
         24 . The apparatus of  claim 20 , wherein:
 the cavities of the injection-mold template have shapes selected from the group including spherical, aspherical, cylindrical, ellipsoidal, paraboloidal, trapezoidal, rectangular, square, or other geometric morphologies and topologies.   
     
     
         25 . An apparatus comprising:
 a substrate containing semiconductor devices, and   a plurality of microoptic elements positioned on said substrate and spaced apart from one another by a predetermined distance and aligned with respect to said substrate to couple radiant energy to a plurality of said semiconductor devices,   said microoptic elements containing polymers or glasses having optical properties and having surfaces shaped for enhancing one or more functions of said microoptic elements.   
     
     
         26 . The apparatus of  claim 25  wherein said microoptic elements are less than 10 micrometers in one dimension. 
     
     
         27 . The apparatus of  claim 25  wherein said microoptic elements are less than 1 micrometers in one dimension. 
     
     
         28 . The apparatus of  claim 25  wherein a plurality of said microelements contain polymers having different indices of refraction. 
     
     
         29 . The apparatus of  claim 25  further including a plurality of C4 solder bumps positioned on said substrate and spaced apart from one another by a predetermined distance and aligned with respect to said substrate to couple electrical signals to a plurality of said semiconductor devices.