Method of manufacturing piezoelectric wafers of saw identification tags

Abstract

The invention provides a method of manufacturing piezoelectric wafers of surface acoustic wave (SAW) identification tags. In one embodiment, the method includes: (1) using a master reticle to form, on each of the piezoelectric wafers, wafer-independent patterns that encode digits of a first significance for SAW identification tags; and (2) using different ones of a library of coding reticles to form, on each of the piezoelectric wafers, wafer-dependent patterns that encode digits of a second significance for SAW identification tags.

1 . A method of manufacturing piezoelectric wafers of surface acoustic wave (SAW) identification tags, comprising: 
 using a master reticle on a stepper to form, in multiple fields across each of said piezoelectric wafers, wafer-independent patterns that encode digits of a first significance for said SAW identification tags; and    using different ones of a library of coding reticles on a stepper to form, in multiple fields across each of said piezoelectric wafers, wafer-dependent patterns that encode digits of a second significance for said SAW identification tags.    
   
   
       2 . The method as recited in  claim 10  wherein said stepper is a programmable stepper.  
   
   
       3 . The method as recited in  claim 10 , further comprising forming a SAW transducer on each of said SAW identification tags.  
   
   
       4 . The method as recited in  claim 10 , further comprising forming said wafer-independent and wafer-dependent patterns by forming reflectors distributed among a group of slots arranged by both pulse position and by phase position, said reflectors encoding said digits of a first significance and said digits of a second significance.  
   
   
       5 . The method as recited in  claim 13  wherein said reflectors are structures that reflect a surface acoustic wave.  
   
   
       6 . The method as recited in  claim 13  further comprising forming a framing reflector on said SAW identification tags, said framing reflector located between said SAW transducer and said group of slots.  
   
   
       7 . The method as recited in  claim 13  further comprising forming a plurality of said group of slots separated by dead spaces.  
   
   
       8 . The method as recited in  claim 16  wherein said plurality of group of slots is at least twelve.  
   
   
       9 . The method as recited in  claim 13  wherein at least some of said reflectors are single strips of conductive metal.  
   
   
       10 . The method as recited in  claim 13  further comprising forming an end reflector on said SAW identification tags.  
   
   
       11 . A method of manufacturing piezoelectric wafers of surface acoustic wave (SAW) identification tags, comprising: 
 establishing wafer-dependent indices for each of said piezoelectric wafers;    using a reticle on a stepper to form, in multiple fields across each of said piezoelectric wafers, wafer-independent patterns that encode digits of a first significance for said SAW identification tags; and    causing said reticle to follow said wafer-dependent indices and thereby form, in multiple fields across each of said piezoelectric wafers, wafer-dependent patterns that encode digits of a second significance for said SAW identification tags.    
   
   
       12 . The method as recited in  claim 20  wherein said reticle is a one power reticle.  
   
   
       13 . The method as recited in  claim 20  wherein said stepper is a programmable stepper.  
   
   
       14 . The method as recited in  claim 22  further comprising programing said stepper for at least one global wafer-dependent index on said wafer.  
   
   
       15 . The method as recited in  claim 20 , further comprising forming a SAW transducer on each of said SAW identification tags.  
   
   
       16 . The method as recited in  claim 20 , further comprising forming said wafer-independent and wafer-dependent patterns by forming reflectors distributed among a group of slots arranged by both pulse position and by phase position, said reflectors encoding said digits of a first significance and said digits of a second significance.  
   
   
       17 . The method as recited in claim  25  wherein said reflectors are structures that reflect a surface acoustic wave.  
   
   
       18 . The method as recited in claim  25  further comprising forming a framing reflector on said SAW identification tags, said framing reflector located between said SAW transducer and said group of slots.  
   
   
       19 . The method as recited in claim  25  further comprising forming a plurality of said group of slots separated by dead spaces.  
   
   
       20 . The method as recited in claim  28  wherein said plurality of group of slots is at least twelve.  
   
   
       21 . The method as recited in claim  25  wherein at least some of said reflectors are single strips of conductive metal.  
   
   
       22 . The method as recited in claim  25  further comprising forming an end reflector on said SAW identification tags.