Method of fabricating a semiconductor work object

Abstract

A method of forming a conductive plug in a contact hole comprising: providing a wafer having a conductive layer comprising silicon adjacent a dielectric layer comprising silicon oxide, and a contact hole disposed in the dielectric layer, the contact hole having surfaces that include sidewalls formed in the dielectric layer and a bottom defined by the conductive layer, a contaminant material being disposed over at least a portion of the conductive layer defining the bottom of the contact hole, the dielectric layer having a surface in which the contact hole terminates in an opening opposing the bottom; depositing a layer of a barrier material on the work object, the layer having a substantially uniform thickness from the surface at the opening of the contact hole to the bottom of the contact hole; and depositing a layer of a protective material barrier around at least opening of the contact hole; etching the material at the bottom of the contact hole to expose the contaminant material while retaining protective material around the opening of the contact hole; etching the contact hole to remove contaminant material disposed over the conductive layer at the bottom of the contact hole; and filling the contact hole with a conductive material to form a plug.

What is claimed:  
     
         1 . A method of preparing a contact hole to receive a conductive plug comprising: 
 providing a work object having a conductive layer adjacent a dielectric layer, and a contact hole disposed in the dielectric layer, the contact hole having surfaces that include sidewalls formed in the dielectric layer and a bottom defined by the conductive layer, the contact hole having an opening for receiving a conductive plug material; and    depositing a layer of protective material on at least the surface around the opening of the contact hole, the material deposited being sufficient to protect the CDs of the contact hole opening during an etch of the contact hole to remove any contaminant material disposed over the conductive layer at the bottom of the contact hole.    
     
     
         2 . The method of  claim 1  further comprising depositing a layer of barrier material over the surfaces of the contact hole before deposition of the protective material, and etching the barrier layer at the bottom of the contact hole to expose any contaminant material, while retaining protective material around the opening of the contact hole following the etch of the barrier layer.  
     
     
         3 . The method of  claim 2  further wherein a dry etch technique is used to etch the barrier layer at the bottom of the contact hole and a wet etch technique is used to etch any contaminant material exposed following the dry etch.  
     
     
         4 . The method of  claim 2  wherein the layer of barrier material comprises a refractory metal based compound extending from the surface at the opening of the contact hole to the bottom of the contact hole; and the layer of protective material comprises a refractory metal based compound extending from the opening of the contact hole to a selected depth into the contact hole.  
     
     
         5 . The method of  claim 1  wherein the conductive layer comprises a silicon based material and the dielectric layer comprises a silicon oxide based material.  
     
     
         6 . The method of  claim 4  wherein the conductive layer comprises a silicon-based material and the dielectric layer comprises a silicon oxide based material.  
     
     
         7 . The method of  claim 2  wherein the layer of protective material is deposited by PVD.  
     
     
         8 . The method of  claim 7  wherein the layer of barrier material is deposited by CVD.  
     
     
         9 . The method of  claim 1  wherein the layer of protective material comprises TiN.  
     
     
         10 . The method of  claim 6  wherein the refractory based compound for at least one of the barrier layer and protective layer comprises TiN.  
     
     
         11 . The method of  claim 4  wherein the layer of protective material is deposited by a CVD process and the layer of protective material is deposited by a PVD process.  
     
     
         12 . The method of  claim 8  wherein the layer of protective material is TiN deposited by a CVD process and the layer of protective material is TiN deposited by a PVD process.  
     
     
         13 . The method of  claim 1  wherein the contact hole has a high aspect ratio.  
     
     
         14 . The method of  claim 4  wherein the contact hole has a high aspect ratio.  
     
     
         15 . The method of  claim 13  wherein the opening of the contact hole at the surface of the dielectric layer has a width of about 2 microns or less.  
     
     
         16 . The method of  claim 14  wherein the opening of the contact hole at the surface of the dielectric layer has a width of about 2 microns or less.  
     
     
         17 . The method of  claim 15  wherein the aspect ratio of the contact hole is about 3:1 or more.  
     
     
         18 . The method of  claim 16  wherein the aspect ratio of the contact hole is about 3:1 or more.  
     
     
         19 . The method of  claim 4  further comprising depositing a layer of a refractory metal on the bottom of the contact hole subsequent to the wet etch.  
     
     
         20 . A method of forming a conductive plug in a contact hole comprising: 
 providing a work object having a conductive layer adjacent a dielectric layer, and a contact hole disposed in the dielectric layer, the contact hole having surfaces that include sidewalls formed in the dielectric layer and a bottom defined by the conductive layer, the contact hole having an opening for receiving a conductive plug material;    depositing a layer of protective material on at least the surface around the opening of the contact hole, the material deposited being sufficient to protect the CDs of the contact hole opening during etching of the contact hole to remove any contaminant material disposed over the conductive layer at the bottom of the contact hole;    etching the protective material at the bottom of the contact hole to expose the contaminant material while retaining protective material around the opening of the contact hole; and    filling the contact hole with a conductive material to form a plug.    
     
     
         21 . The method of  claim 20  wherein the conductive layer is silicon based and the dielectric layer is a silicon oxide.  
     
     
         22 . The method of  claim 21  further comprising depositing a layer of barrier material over the surfaces of the contact hole before deposition of the protective material, and etching the barrier layer at the bottom of the contact hole to expose any contaminant material, while retaining protective material around the opening of the contact hole following the etch of the barrier layer.  
     
     
         23 . The method of  claim 22  further wherein a dry etch technique is used to etch the barrier layer at the bottom of the contact hole and a wet etch technique is used to etch any contaminant material exposed following the dry etch.  
     
     
         24 . The method of  claim 23  wherein the layer of barrier material comprises a refractory metal based compound extending from the surface at the opening of the contact hole to the bottom of the contact hole; and the layer of protective material comprises a refractory metal based compound extending from the opening of the contact hole to a selected depth into the contact hole.  
     
     
         25 . The method of  claim 22  wherein the layer of protective material is deposited by PVD.  
     
     
         26 . The method of  claim 25  wherein the layer of barrier material is deposited by CVD.  
     
     
         27 . The method of  claim 25  wherein the layer of protective material comprises TiN.  
     
     
         28 . The method of  claim 24  wherein the refractory based compound for at least one of the barrier layer and protective layer comprises TiN.  
     
     
         29 . The method of  claim 24  wherein the first layer of protective material is deposited by a CVD process and the second layer of protective material is deposited by a PVD process.  
     
     
         30 . The method of  claim 24  wherein the first layer of protective material is TiN deposited by a CVD process and the second layer of protective material is TiN deposited by a PVD process.  
     
     
         31 . The method of  claim 22  wherein the contact hole has a high aspect ratio.  
     
     
         32 . The method of  claim 29  wherein the contact hole has a high aspect ratio.  
     
     
         33 . The method of  claim 31  wherein the opening of the contact hole at the surface of the dielectric layer has a width of about 2 microns or less.  
     
     
         34 . The method of  claim 32  wherein the opening of the contact hole at the surface of the dielectric layer has a width of about 2 microns or less.  
     
     
         35 . The method of  claim 33  wherein the aspect ratio of the contact hole is about 3:1 or more.  
     
     
         36 . The method of  claim 34  wherein the aspect ratio of the contact hole is about 3:1 or more.  
     
     
         37 . The method of  claim 23  further comprising depositing a layer of a refractory metal on the bottom of the contact hole subsequent to the wet etch.  
     
     
         38 . A method of forming a conductive plug in a contact hole comprising: 
 providing a wafer having a conductive layer comprising silicon adjacent a dielectric layer comprising silicon oxide, and a contact hole disposed in the dielectric layer, the contact hole having surfaces that include sidewalls formed in the dielectric layer and a bottom defined by the conductive layer, a contaminant material being disposed over at least a portion of the conductive layer defining the bottom of the contact hole, the dielectric layer having a surface in which the contact hole terminates in an opening opposing the bottom;    depositing a layer of a barrier material on the work object, the layer having a substantially uniform thickness from the surface at the opening of the contact hole to the bottom of the contact hole; and depositing a layer of a protective material barrier around at least the opening of the contact hole;    etching the material at the bottom of the contact hole to expose the contaminant material while retaining protective material around the opening of the contact hole;    etching the contact hole to remove contaminant material disposed over the conductive layer at the bottom of the contact hole; and    filling the contact hole with a conductive material to form a plug.    
     
     
         39 . The method of  claim 38  wherein the opening of the contact hole at the surface of the dielectric layer has a width of about 2 microns or less.  
     
     
         40 . The method of  claim 39  wherein the aspect ratio of the contact hole is about 3:1 or more.  
     
     
         41 . The method of  claim 38  wherein a dry etch is used to expose protective material over the contaminant material.  
     
     
         42 . The method of  claim 41  wherein a wet etch is used to remove the contaminant material at the bottom of the contact hole.  
     
     
         43 . The method of  claim 40  wherein a dry etch is used to expose protective material over the contaminant material.  
     
     
         44 . The method of  claim 43  wherein a wet etch is used to remove the contaminant material at the bottom of the contact hole.  
     
     
         45 . The method of  claim 38  further comprising depositing a metal over the conductive layer prior to filling the contact hole with the conductive material to form the plug.  
     
     
         46 . The method of  claim 42  further comprising depositing a metal over the conductive layer prior to filling the contact hole with the conductive material to form the plug.  
     
     
         47 . The method of  claim 46  further comprising forming a barrier layer over the deposited metal.  
     
     
         48 . The method of  claim 46  wherein the metal comprises Ti.  
     
     
         49 . The method of  claim 47  wherein the barrier layer comprises TiN.  
     
     
         50 . The method of  claim 45  wherein the metal comprises Ti.  
     
     
         51 . The method of  claim 45  wherein a barrier layer is formed over the deposited metal.  
     
     
         52 . The method of  claim 20  wherein the conductive plug comprises tungsten.  
     
     
         53 . The method of  claim 20  wherein the conductive plug material comprises Al, Au, Cu, or Ag.  
     
     
         54 . The method of  claim 22  further comprising depositing a metal over the conductive layer before depositing the material for the conductive plug.  
     
     
         55 . The method of  claim 54  further comprising depositing a barrier layer over the deposited metal before depositing the material for the conductive plug.  
     
     
         56 . The method of  claim 54  wherein the deposited metal comprises Ti.  
     
     
         57 . The method of  claim 55  wherein the barrier metal comprises TiN.  
     
     
         58 . The method of  claim 57  wherein the conductive plug comprises tungsten.  
     
     
         59 . The method of  claim 20  wherein the contact hole comprises a via.  
     
     
         60 . The method of  claim 1  wherein the contact hole comprises a container for a capacitor.