Metal plated spring structure

Abstract

Efficient methods are disclosed for fabricating metal plated spring structures in which the metal is plated onto the spring structure after release. A conductive release layer is deposited on a substrate and a spring metal layer is then formed thereon. A first mask is then used to form a spring metal finger, but etching is stopped before the release layer is entirely removed. A second mask is then deposited that defines a release window used to remove a portion of the release layer and release a free end of the spring metal finger. The second mask is also used to plate at least some portions of the free end of the finger and selected structures exposed through the second mask. Remaining portions of the release layer are utilized as electrodes during electroplating. The resulting spring structure includes plated metal on both upper and lower surfaces of the finger.

1 . A spring structure comprising: 
 a substrate;    a release material portion located over the substrate;    a spring metal finger having an anchor portion attached to the release material portion such that the release material portion is located between the anchor portion and the substrate, the spring metal finger also having a free portion extending over the substrate, the free portion having opposing first and second surfaces; and    a plated metal layer formed on both the first and second surfaces of the free portion of the spring metal finger.    
     
     
         2 . The spring structure according to  claim 1 , wherein the spring metal finger comprises at least one of Molybdenum (Mo) and Chromium (Cr), and the plated metal layer comprises Nickel (Ni).  
     
     
         3 . The spring structure according to  claim 1 , wherein the release material portion is electrically conductive.  
     
     
         4 . The spring structure according to  claim 3 , wherein the release material portion comprises at least one metal selected from the group consisting of Ti, Cu, Al, Ni, Zr, and Co.  
     
     
         5 . The spring structure according to  claim 3 , wherein the release material portion comprises heavily doped silicon.  
     
     
         6 . The spring structure according to  claim 3 , further comprising a conductor formed on the substrate, wherein the spring metal finger is electrically connected to the conductor via the release material portion.  
     
     
         7 . The spring structure according to  claim 1 , wherein the plated metal layer includes a second portion formed on the anchor portion of the spring metal finger.