Patent ID: 8240027

Claim:
A method of making a circuitized substrate having circuitry including a plurality of film resistors as part thereof, said method comprising: providing a conductive layer having a layer of resistor material thereon; providing a dielectric layer; bonding said conductive layer having said layer of resistor material thereon to said dielectric layer such that said layer of resistor material directly contacts said dielectric layer; removing selected portions of said conductive layer and said resistor material to form a plurality of individual members each including a length and width of said resistor material and a portion of said conductive layer thereon; removing selected portions of said portion of said conductive layer on each of said individual members to define first and second spaced apart conductors on said length and width of said resistor material of each of said individual members and thereby define a plurality of individual film resistors; measuring resistance values across said resistor material at predefined locations thereof; determining a representative resistance value of a representative film resistor of said plurality of individual film resistors in a predetermined region as a sample of sheet resistance according to said length and width dimensions of said resistor material of said representative film resistor; utilizing said representative resistance value of said representative film resistor to determine the precise width of said resistor material of selected ones of the remaining individual film resistors of said plurality of individual resistors within a predetermined distance of said representative film resistor so as to provide a desired resistance value for each of said selected ones of said remaining individual film resistors in said region; etching a pattern of lines within said resistor material of each of said selected ones of said remaining individual film resistors to define a precise width of said resistor material for each of said selected ones of said remaining individual film resistors in order that said selected ones of said remaining individual film resistors will each possess said desired resistance; and trimming said individual film resistors exclusive of subsequent resistance measuring.