LIGA developer apparatus system

Abstract

A system to fabricate precise, high aspect ratio polymeric molds by photolithograpic processe is described. The molds for producing micro-scale parts from engineering materials by the LIGA process. The invention is a developer system for developing a PMMA photoresist having exposed patterns comprising features having both very small sizes, and very high aspect ratios between part minimum feature size and part overall dimension. The developer system of the present invention comprises a developer tank, an intermediate rinse tank and a final rinse tank, each tank having a source of high frequency sonic agitation, temperature control, and continuous filtration. It has been found that by moving a patterned, LIGA wafer, through a specific sequence of developer/rinse solutions, wherein the solutions are agitated with a source of high frequency sonic vibration, wherein the solution temperature of each tank is adjusted and closely controlled, and wherein the solutions are continuously recirculated and filtered, it is possible to maintain the kinetic dissolution of the exposed PMMA polymer as the rate limiting step.

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         17 . A polymeric mold for producing a micro-scale part comprising: 
 a mold substrate, said substrate having an intermediate adhesion layer;    one or more polymer layers on said intermediate layer, said one or more layers having a thickness of about 50 microns greater than a thickness of a part to be produced; and    features within said one or more layers having dimensions of up to three orders of magnitude smaller than said part thickness or said part diameter or length.    
     
     
         18 . The mold of  claim 17 , wherein the photoresist layer further comprises PMMA.  
     
     
         19 . The mold of  claim 17 , wherein the mold substrate is selected from the group of materials consisting of silicon, metals, or ceramics, and combinations thereof.  
     
     
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