Method for trimming resistors

Abstract

There is provided a method and circuit for trimming a functional resistor on a thermally isolated micro-platform such that a second functional resistor on the same micro-platform remains substantially untrimmed; a method and circuit for providing and trimming a circuit such that at least two circuit elements of the circuit are subjected to a same operating environment and the operating environment is compensated for by distributing heat generated during operation of the circuit among the two circuit elements; a method and circuit for trimming a functional resistor on a thermally-isolated micro-platform such that a constant temperature distribution is obtained across the functional resistor; and a method and circuit for calculating a temperature coefficient of resistance of a functional resistor.

1 . A method for trimming a functional resistor, the method comprising: 
 placing a plurality of thermally-trimmable functional resistors on a substrate such that they are thermally-isolated;    subjecting a portion of the substrate to a heat pulse such that a resistance value of one of said plurality of functional resistors is trimmed while a resistance value of remaining ones of said plurality of functional resistors remains substantially untrimmed.    
   
   
       2 . A method as claimed in  claim 1 , further comprising providing a thermally-isolated micro-platform on said substrate, and said placing a plurality of thermally-trimmable functional resistors on a substrate comprises placing said plurality of thermally-trimmable functional resistors on said thermally-isolated micro-platform.  
   
   
       3 . A method as claimed in  claim 2 , further comprising placing a heating resistor on the thermally-isolated micro-platform in close proximity to at least one of the plurality of functional resistors, wherein said subjecting a portion of the thermally-isolated micro-platform further comprises passing a signal through the heating resistor to increase its temperature significantly for the purpose of trimming said at least one of said plurality of functional resistors without substantially affecting remaining ones of the plurality of functional resistors on the thermally-isolated micro-platform  
   
   
       4 . A method as claimed in  claim 3 , wherein placing a heating resistor on the thermally-isolated micro-platform further comprises placing said heating resistor such that it is electrically isolated from said at least one of the plurality of functional resistors.  
   
   
       5 . A method as claimed in  claim 2 , wherein said subjecting comprises providing a plurality of electrical pulses and measuring said resistance value of one of said plurality of functional resistors in between each of said plurality of electrical pulses to determine whether a target resistance value has been obtained.  
   
   
       6 . A method as claimed in  claim 2 , wherein said heating comprises providing dynamically-shaped electrical pulses to achieve substantially constant temperature as a function of time during a trimming pulse.  
   
   
       7 . A method as claimed in  claim 3 , wherein said placing a heating resistor on the thermally-isolated micro-platform further comprises placing said heating resistor such that it traces said at least one of said plurality of functional resistors.  
   
   
       8 . A method as claimed in  claim 7 , wherein said heating resistor is placed along an outside portion of said functional resistor to obtain a substantially constant temperature distribution across said functional resistor.  
   
   
       9 . A method as claimed in  claim 2 , further comprising raising said thermally-isolated micro-platform's temperature to trim downwards values of all trimmable functional resistors on said thermally-isolated micro-platform, measuring said trimmable functional resistors, and individually trimming upwards each of said trimmable functional resistors.