Method and structure for interfacing electronic devices

Abstract

Method and structure for optimizing and controlling diffusional creep at metal contact interfaces are disclosed. Embodiments of the invention accommodate height variations in adjacent contacts, decrease planarization uniformity requirements, and facilitate contact bonding at lower temperatures and pressures by employing shapes and materials that respond predictably to compressive interfacing loads.

1 - 26 . (canceled)  
     
     
         27 . An apparatus comprising: 
 a plurality of contacts protruding from a substrate surface; and    at least one displacement limiting structure protruding from the substrate surface.    
     
     
         28 . The apparatus of  claim 27 , wherein the protrusion height of the at least one displacement limiting structure is less than the average protrusion height of the plurality of contacts and the width of the at least one displacement limiting structure is greater than the width of the plurality of contacts.  
     
     
         29 . The apparatus of  claim 28 , wherein the protrusion height of the at least one displacement limiting structure is less than the average protrusion height of the plurality of contacts by about one to five times the square root of the variance of the protrusion heights of the plurality of contacts.  
     
     
         30 . The apparatus of  claim 28 , wherein the width of the at least one displacement limiting structure is about 20 microns and the width of the plurality of contacts is about 6 microns.  
     
     
         31 . The apparatus of  claim 28 , wherein the at least one displacement limiting structure has a bottom surface and the plurality of contacts have bottom surfaces, the bottom surface of the displacement limiting structure and the bottom surfaces of the plurality of contacts being at substantially the same depth relative to the substrate surface.  
     
     
         32 . The apparatus of  claim 27 , wherein the at least one displacement limiting structure and the plurality of contacts comprise at least one of copper, gold, or silver.  
     
     
         33 . The apparatus of  claim 27 , wherein the at least one displacement limiting structure comprises a plurality of small protruding structures.  
     
     
         34 . The apparatus of  claim 33 , wherein a substrate surface between the small protruding structures protrudes above the level of the substrate surface.  
     
     
         35 . The apparatus of  claim 27 , further comprising: 
 a second displacement limiting structure; and    a third displacement limiting structure, wherein the at least one, the second, and the third displacement limiting structures have lengths and widths along the substrate surface, the lengths of the at least one, the second, and the third displacement limiting structures being substantially greater than the widths of the at least one, the second, and the third displacement limiting structures, and the plurality of contacts being distributed between the at least one and second displacement limiting structures and between the second and third displacement limiting structures.    
     
     
         36 . The apparatus of  claim 27 , wherein the at least one displacement limiting structure forms a perimeter around the plurality of contacts, the at least one displacement structure having a width and a perimeter length along the substrate surface, and the perimeter length of the displacement structure being substantially greater than the width of the displacement structure.  
     
     
         37 . The apparatus of  claim 27 , further comprising: 
 a plurality of displacement limiting structures dispersed about the plurality of contacts, the plurality of displacement limiting structures having lengths and widths along the substrate surface, the lengths and widths being about equal.    
     
     
         38 . The apparatus of  claim 27 , further comprising: 
 a plurality of second contacts protruding from a second substrate surface; and    at least one second displacement limiting structure protruding from the second substrate surface, wherein the at least one displacement limiting structure and the at least one second displacement limiting structure are in contact, and at least one of the plurality of contacts and at least one of the plurality of second contacts form an electrical connection.    
     
     
         39 . A method comprising: 
 forming a plurality of contacts in trenches in a dielectric layer on a substrate;    forming at least one displacement limiting structure in at least one trenche in the dielectric layer; and    decreasing the height of the at least one displacement limiting structure relative to the height of the contacts.    
     
     
         40 . The method of  claim 39 , wherein the width of the at least one displacement limiting structure is greater than the width of the plurality of contacts, and decreasing the height of the at least one displacement limiting structure comprises decreasing the height of the at least one displacement limiting structure by chemical mechanical polishing.  
     
     
         41 . The method of  claim 40 , wherein the chemical mechanical polishing is controlled by polish time and slurry type to cause dishing that polishes the at least one displacement limiting structure faster than the plurality of contacts.  
     
     
         42 . The method of  claim 39 , wherein decreasing the height of the at least one displacement limiting structure comprises decreasing the height of the at least one displacement limiting structure by local patterning and etching treatments.  
     
     
         43 . The method of  claim 39 , further comprising: 
 etching the dielectric layer to form structural voids between the plurality of contacts and the at least one displacement limiting structure.    
     
     
         44 . The method of  claim 39 , wherein the at least one displacement limiting structure and the plurality of contacts comprise at least one of copper, gold, or silver.  
     
     
         45 . A method comprising: 
 forming a plurality of contacts and at least one displacement limiting structure in trenches in a dielectric layer on a substrate, the displacement limiting structure comprising a plurality of small structures; and    decreasing the height of the dielectric layer between the contacts relative to the height of the dielectric layer between the small structures.    
     
     
         46 . The method of  claim 45 , wherein decreasing the height of the dielectric layer between the contacts relative to the height of the dielectric layer between the small structures comprises localized patterning and etching.  
     
     
         47 . The method of  claim 45 , wherein decreasing the height of the dielectric layer between the contacts relative to the height of the dielectric layer between the small structures comprises chemical mechanical polishing.