Through-silicon via structure and method for making the same

Abstract

A through-silicon via structure includes a substrate with a first side and a second side, a through-silicon hole connecting the first side and the second side and filled with a conductive material, a passivation layer disposed on and contacting the first side and covering the through-silicon hole, and a protection ring surrounding but not contacting the through-silicon hole and exposed by the first side and the second side. The protection ring is filled with an insulating material.

1 . A through-silicon via (TSV) structure, comprising:
 a substrate with a first side and a second side opposite to said first side;   a through-silicon hole connecting said first side and said second side and filled with a first conductive material;   a passivation layer comprising a second conductive material and disposed on and contacting said first side and covering said through-silicon hole; and   a protection ring surrounding but not contacting said through-silicon hole, exposed by said first side and said second side and filled with an insulating material.   
   
   
       2 . The through-silicon via structure of  claim 1 , wherein said substrate further comprises a shallow trench isolation. 
   
   
       3 . The through-silicon via structure of  claim 1 , wherein said passivation layer comprises a gate structure. 
   
   
       4 . The through-silicon via structure of  claim 1 , wherein said passivation layer comprises a contact etch stop layer (CESL). 
   
   
       5 . The through-silicon via structure of  claim 1 , wherein said passivation layer covers said protection ring. 
   
   
       6 . The through-silicon via structure of  claim 1 , wherein the diameter of said through-silicon hole is larger than the ring width of said protection ring. 
   
   
       7 . The through-silicon via structure of  claim 1 , wherein said through-silicon hole further comprises at least one of a barrier layer and a liner. 
   
   
       8 . The through-silicon via structure of  claim 1 , wherein said substrate is sandwiched between said through-silicon hole and said protection ring. 
   
   
       9 . The through-silicon via structure of  claim 1 , wherein said through-silicon hole is intrinsically deeper than said protection ring. 
   
   
       10 . The through-silicon via (TSV) structure of  claim 1 , wherein said conductive material bulges from said second side. 
   
   
       11 . A method for forming a through-silicon via (TSV) structure, comprising:
 providing a substrate with a first side and a second side opposite to said first side;   performing an etching procedure to form a through-silicon hole and a protection trench, so that said protection trench surrounds said through-silicon hole, wherein said through-silicon hole is deeper than said protection ring;   filling said protection trench and said through-silicon hole with an insulating material;   forming a passivation layer comprising a first conductive material and disposed on said first side and covering said through-silicon hole;   thinning said substrate from said second side to expose said insulating material in said through-silicon hole; and   replacing said insulating material in said through-silicon hole with a second conductive material to form said through-silicon via structure.   
   
   
       12 . The method of  claim 11 , further comprising:
 continuing to thin said substrate from said second side to expose said insulating material in said protection trench to form a protection ring.   
   
   
       13 . The method of  claim 12 , wherein said passivation layer covers said protection ring. 
   
   
       14 . The method of  claim 12 , wherein said through-silicon hole does not contact said protection ring. 
   
   
       15 . The method of  claim 12 , wherein said conductive material bulges from said second side. 
   
   
       16 . The method of  claim 11 , further comprising:
 forming a pad oxide layer on said substrate;   forming a nitride layer on said pad oxide layer; and   forming a shallow trench isolation in said substrate.   
   
   
       17 . The method of  claim 11 , wherein the diameter of said through-silicon hole is larger than the trench width of said protection trench so that said etching procedure results in said through-silicon hole being deeper than said protection ring. 
   
   
       18 . The method of  claim 11 , further comprising:
 forming at least one of a barrier layer and a liner in said through-silicon hole.   
   
   
       19 . The method of  claim 11 , wherein said passivation layer is selected from a group consisting of a gate structure, a metal interconnection and a contact etch stop layer (CESL). 
   
   
       20 . The method of  claim 11 , wherein thinning said substrate from said second side is carried out by a chemical mechanical polishing procedure. 
   
   
       21 . The method of  claim 11 , between filling said protection trench and said through-silicon hole with said insulating material and thinning said substrate from said second side further comprising:
 performing a semiconductor process selected from a group consisting of a gate process, a source/drain process and an interconnect process.