Optically monitoring an alox fabrication process

Abstract

A method of forming an insulator that passes through a metal substrate ( 302 ) comprising: anodizing a region ( 312 a , 312 b , 314,316 a , 316 b , 318, 320 a , 320 b , 322, 324 a , 324 b ) of the substrate to form the insulator; illuminating the region with light ( 330 ); and determining if the light passes through the substrate at the region to determine if the insulator passes completely through the substrate.

1 . A method of forming an insulator that passes through a metal substrate comprising:
 anodizing a region of the substrate to form the insulator;   illuminating the region with light; and   determining if the light passes through the substrate at the region to determine if the insulator passes completely through the substrate.   
   
   
       2 . A method according to  claim 1  and comprising determining a pattern for the light that passes through the substrate. 
   
   
       3 . A method according to  claim 2  and comprising determining whether the pattern is satisfactory. 
   
   
       4 . A method according to  claim 3  and comprising deeming that the insulator is satisfactorily formed when the pattern is satisfactory. 
   
   
       5 . A method according to  claim 3  and comprising stopping anodization when the pattern is satisfactory. 
   
   
       6 . A method according to any of  claims 1 - 5  wherein determining if the light passes through the region comprises determining during anodization. 
   
   
       7 . A method according to any of  claims 1 - 5  wherein determining if the light passes through the region comprises determining when anodization has stopped. 
   
   
       8 . A method of forming an insulator that passes through a metal substrate comprising:
 anodizing a region of the substrate to form the insulator;   illuminating the region with light; and   stopping anodization when a sufficient amount of light passes through the substrate at the region.   
   
   
       9 . A method of making an interconnect substrate comprising an insulated via that passes through the substrate, comprising forming an insulator in accordance with any of  claims 1 - 8  that completely surrounds a region of non-anodized metal. 
   
   
       10 . A method according to any of  claims 1 - 9  wherein the metal is a valve metal. 
   
   
       11 . Apparatus for forming an insulator that passes through a metal substrate comprising:
 apparatus for anodizing a region of the substrate to form the insulator;   a light source configured to illuminate the region with light; and   at least one detector positioned to receive light that passes through the substrate at the region.   
   
   
       12 . Apparatus according to  claim 11  and comprising a scanning mechanism that moves the substrate relative to the detector so that light passing through the region is incident on the at least one detector. 
   
   
       13 . Apparatus according to  claim 12  wherein the scanning mechanism moves the substrate relative to the light source so that light passing through the region is incident on the at least one detector. 
   
   
       14 . Apparatus according to  claim 12  or  claim 13  wherein the scanning mechanism moves the substrate. 
   
   
       15 . Apparatus according to any of  claims 12 - 14  wherein the scanning mechanism moves the light source. 
   
   
       16 . Apparatus according to any of  claims 12 - 15  wherein the scanning mechanism moves the at least one detector. 
   
   
       17 . Apparatus according to any of  claims 11 - 16  wherein the at least one detector comprises a microscope. 
   
   
       18 . Apparatus according to any of  claims 11 - 17  wherein the light source is configured to illuminate the substrate during anodizing.