Micromachined structures made by combined wet and dry etching

Abstract

A micromachined structure, comprising: a substrate; a first wet etched pit disposed in the substrate; a second wet etched pit disposed in the substrate, the second pit extending into the substrate a greater depth than the first pit; and a dry pit disposed between, and adjacent to, the first and second pits. Also disclosed is a micromachined substrate comprising: a wet etched pit; and a dry-etched hole disposed in the wet etched pit, wherein the dry hole extends through the substrate.

1 - 14 . (canceled)  
   
   
       15 . A method for micromachining a substrate, comprising: 
 providing a hard mask on a selected portion of the substrate to provide a region of the substrate without a hard mask;    removing a portion of the substrate adjacent the region without the hard mask using one or more of ultrasonic drilling, laser etching, sawing and electrochemical etching to provide a micromachined feature in the substrate; and    wet etching the substrate to provide a wet etched feature adjacent to the micromachined feature.    
   
   
       16 . The method according to  claim 15 , comprising providing a fugitive material in the micromachined feature prior to wet etching the substrate.  
   
   
       17 . The method according to  claim 16 , wherein the fugitive material comprises one or more of a polymer, wax, and photoresist.