Fabrication of Ruthenium and Ruthenium Alloy Sputtering Targets with Low Oxygen Content

Abstract

Sputtering targets of ruthenium, ruthenium alloy, and mixtures thereof with other elemental metals, alloys, nonmetals, or ceramic materials are prepared with low oxygen content of 200 ppm or less by hydrogen reduction of the preform prior to encapsulation, HIPing (hot isostatic pressing), and machining to form a sputter target.

1 . A method for fabricating preforms for sputtering targets, said method comprising the steps of fabricating a preform from a mixture of powders selected from the group consisting of ruthenium, ruthenium alloy and mixtures thereof, and subjecting the preform to hydrogen reduction.  
   
   
       2 . The method of  claim 1  wherein the oxygen content of the preform after hydrogen reduction is 200 ppm or less.  
   
   
       3 . The method of  claim 1  wherein the step of subjecting the preform to hydrogen reduction comprises heating the preform in a hydrogen atmosphere at a temperature of from about 500 to 3,800° F.  
   
   
       4 . The method of  claim 3  wherein the hydrogen atmosphere is at a pressure of about 1000 psi or less.  
   
   
       5 . The method of  claim 4  wherein the hydrogen atmosphere is at a pressure less than atmospheric.  
   
   
       6 . The method of  claim 1  wherein the mixture of powders further comprises additional powders selected from the group consisting of other elemental metals, alloys, nonmetal materials, ceramics, and mixtures thereof.  
   
   
       7 . The method of  claim 1  wherein the step of fabricating the preform includes the steps of blending precursor powders to provide a homogeneous mixture of powders and forming preforms from the mixture at a pressure of from about 10 to 100 ksi.  
   
   
       8 . The method of  claim 1  further comprising the steps of encapsulating the preform in a deformable metal canister and hot isostatic pressing the preform.  
   
   
       9 . The method of  claim 8  wherein the step of hot isostatic pressing the perform is at a temperature from about 500 to 3,800° F. and at a pressure from about 5 to 50 ksi for a period of time of from about 1 to 24 hours.  
   
   
       10 . A method for fabricating ruthenium and ruthenium alloy sputtering targets, having an oxygen content of 200 ppm or less, said method comprising the steps of: 
 a) blending precursor powders to provide a homogeneous mixture, the powders selected from the group consisting of ruthenium, ruthenium alloy, and mixtures thereof;    b) forming preforms of the homogeneous mixture at a pressure from 10 to 100 ksi;    c) heating the preform in a hydrogen atmosphere at a temperature of from about 500 to 3,800° F. and at a pressure of about 1,000 psi or less;    d) encapsulating the perform in a deformable metal canister;    e) hot isostatic pressing the pre-form at a temperature from about 500 to 3,800° F. and at a pressure from about 5 to 50 ksi for a period of time of from about 1 to 24 hours; and    f) machining the pre-form to form a sputter target.    
   
   
       11 . The method of  claim 10  wherein the ruthenium alloy comprises an alloy of ruthenium and another metal, nonmetal, or ceramic material.  
   
   
       12 . The method of  claim 10  wherein the precursor powders include in addition to elemental ruthenium or ruthenium alloy or both a powder selected from the group consisting of other elemental metals, alloys, nonmetals, ceramics, and mixtures thereof.  
   
   
       13 . The method of  claim 10  wherein the preform is heated in a hydrogen atmosphere by placing the preform in a hydrogen reduction furnace.