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Thin Film Resistors With Underlay

IP.com Disclosure Number: IPCOM000095563D
Original Publication Date: 1964-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Chapman, RM: AUTHOR

Abstract

In this reproducible thin film resistor geometry use is made of an underlay. The method is one of depositing a precise thin film resistor by the use of an accurately dimensioned underlay.

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Thin Film Resistors With Underlay

In this reproducible thin film resistor geometry use is made of an underlay. The method is one of depositing a precise thin film resistor by the use of an accurately dimensioned underlay.

Initially, substrate 10 has deposited on it a pair of spaced silk screened, fired on, gold conductors or terminals 11 and 12. Next, non-conducting underlay layer 13 of silicon monoxide evaporated film is deposited through a mask opening with precisely spaced ends over terminals 11 and 12. Finally, thin film resistance strip 14 is evaporated over underlay 13 and beyond the ends of the overlay and onto the gold of terminals 11 and 12. Since underlay 13 is of an accurately defined length and has sharply defined ends, the resistance element strip is of an accurate, predictable electrical resistance value.

The geometry of resistor film 14 is precisely determined by the use of a high precision mask. However, the effective length of the resistor is dependent upon the terminal conductor pattern deposited below the resistor. If it were practical to deposit a thin film conductor terminal pattern through a mask, the edges of it could also be held to very close tolerance. However, since it is more desirable to use silk screened, fired on, gold conductor terminals which have poor edge definition, the remedy for the shortcomings of the gold terminals is the use of the precise underlay 13 of this arrangement.

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