Method of making multilevel MEMS structures

Abstract

Multi-levels are etched into silicon. The levels are etched through a combination of crosslinking photoresist, multiple photoresist patterning and development, wet etching and/or dry-etching. RIE, DRIE, and other etch techniques can be used during different steps. The multilevel structure may thereby be produced at commercially acceptable production rates allowing the method of the present application to be used in volume production of multilevel structures.

1 . A micro-machined structure comprising: 
 three levels in a substrate, the levels created by a combination of patterning and developing a first photoresist, crosslinking said first photoresist, patterning and developing a second layer of photoresist on the crosslinked said first photoresist and said substrate, and a combination of etching and removing said first and remaining said second photoresists resulting in a 3-level structure.    
     
     
         2 . A micro-machined structure comprising: 
 four levels in a substrate, the levels created by a combination of laying a wet etchable second substrate, patterning and developing a first photoresist, wet etching said second substrate several times, patterning and developing a second photoresist, crosslinking said second photoresist, patterning and developing a third layer of photoresist on the crosslinked photoresist and said second substrate, and etching said substrate to at least four levels.    
     
     
         3 . A micro-machined structure comprising: 
 multiple levels in a substrate, the levels created by a combination of laying a wet etchable second substrate, patterning and developing a first photoresist, etching said second substrate several times, patterning and developing a second photoresist, crosslinking said second photoresist, patterning and developing a third layer of photoresist on the crosslinked photoresist and said second substrate, etching said substrate to at least four levels, then repeating portions of the process for the desired number of levels beyond four levels.    
     
     
         4 . A micro-machined structure comprising: 
 multiple levels in a substrate, the levels created by a combination of patterning and developing a first photoresist, crosslinking said first photoresist, patterning and developing a second layer of photoresist on the crosslinked said first photoresist and said substrate, and a combination of etching and removing said first and remaining said second photoresists resulting in a 3-level structure, then repeating portions of the process for the desired number of levels beyond three levels.