Metallized resistor and methods of manufacturing and adjusting the resistance of same

• US 4,298,856 A
• Filed: 09/04/1979
• Issued: 11/03/1981
• Est. Priority Date: 09/04/1979
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: Western Electric Co., Inc. (Nokia Corporation)
• Inventors: Schuchardt, Donald W.
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US06/072,371
• Time in Patent Office: 791 Days
• Field of Search: 338/195, 338/308, 338/309, 338/314, 338/49, 338/322, 338/324, 338/325, 29/620
• US Class Current: 338/195
• CPC Class Codes: H01C 17/23 by opening or closing resistor geometric tracks of predetermined resistive values, e.g. snapistors
• CPC Class Codes: H05K 1/0268 for electrical inspection or testing
• CPC Class Codes: H05K 1/0293 Individual printed conductors which are adapted for modification, e.g. fusable or breakable conductors, printed switches
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/0305 Solder used for other purposes than connections between PCB or components, e.g. for filling vias or for programmable patterns
• CPC Class Codes: H05K 2201/09263 Meander
• CPC Class Codes: H05K 2201/10287 Metal wires as connectors or conductors
• CPC Class Codes: H05K 2203/171 Tuning, e.g. by trimming of printed components or high frequency circuits
• CPC Class Codes: H05K 2203/175 Configurations of connections suitable for easy deletion, e.g. modifiable circuits or temporary conductors for electroplating; Processes for deleting connections
• CPC Class Codes: H05K 3/222 Completing of printed circuits by adding non-printed jumper connections printed jumper connections H05K3/4685
• CPC Class Codes: Y10T 29/49099 Coating resistive material on a base

Abstract

Several planar configured, metallized resistor embodiments (25, 35, 45, 55, 65) are disclosed, as are several methods of manufacturing and resistance trimming the same, particularly to values of resistance lower than the "as fabricated" nominal value thereof. In accordance with one preferred resistor embodiment (25), a plurality of associated discrete conductive bonding pads (29) are formed on a common supporting substrate (27), with each pad being in conductive contact with a different spaced site along the body portion (25a) of the resistor between the terminating ends thereof. The bonding pads (29) are advantageously adapted to allow bonded wire connections to be made between different selected pairs thereof, after fabrication of the resistor, whenever necessary to incrementally reduce the initial nominal value of resistance of the resistor to a lower desired value.

In accordance with several other resistor embodiments (35, 55, 65), the bonding pads (41 and 42, 59, 72) thereof are arranged in clusters so as to allow the use of solder bridges, as well as bonded wires, to interconnect selected ones of adjacent pairs of the pads as required to establish a desired lower value of resistance.

Also in accordance with the principles of the invention, one illustrative resistor (45) incorporates a plurality of short-circuiting shunts (52), in addition to a plurality of bonding pads (47). The shunts are interconnected to the body portion (45a) of the resistor at different spaced sites therealong such that when selectively opened, the then existing value of resistance of the resistor is incrementally increased, whereas when short-circuit connections are selectively established between different pairs of the bonding pads (47), the then existing resistance of the resistor is incrementally decreased.

Claims

1. An adjustable planar configured resistor comprising:

insulative support mean;

a relatively thin layer of resistive material formed in a desired configuration on, and supported by, said support means, said resistive layer defining the main body portion of said resistor, and having at least two conductive terminals connected to end regions thereof for completing electrical connections to said main body portion, said body portion comprising a thin-film layer of resistive material formed into a series of closely spaced, serially connected segments arranged in a serpentine configuration;

a plurality of conductive bonding pads formed as an integral part, and on the upper side, of respective discrete areas of said thin film resistor body portion between at least said two terminals thereof, said bonding pads being of sufficient cross section to allow conductive short-circuiting interconnections to be made between different selected pairs thereof, after fabrication of the resistor, whenever necessary to reduce the initial nominal value of resistance of said resistor to a lower desired value.

2. An adjustable resistor in accordance with claim 1 wherein at least one conductive wire is bonded at opposite ends to different ones of a predetermined spaced pair of said bonding pads so as to short-circuit that part of the resistor body portion therebetween and, thereby, lower the nominal value of resistance of said resistor as fabricated to a desired value for a given circuit application.

3. An adjustable planar confined resistor comprising:

insulative support means;

a relatively thin layer of resistive material formed in a desired configuration on, and supported by, said support means, said resistive layer defining the main body portion of said resistor, and having at lest two conductive terminals connected to end regions thereof for completing electrical connections to said main body portion, said body portion comprising a thin-film layer of resistive material formed into a series of closely spaced, serially connected segments arranged in a serpentine configuration, and,

a plurality of conductive bonding pads formed as an integral part, and on the upper side, of respective discrete areas of said thin film resistor body portion between at least said two terminals thereof, said bonding pads being of sufficient cross-section, and arranged on said resistor body portion such that at least selected adjacent ones of said pads are spaced sufficiently close, to allow short-circuiting solder bridges and bonded interconnections to be selectively formed therebetween so as to lower the nominal resistance of said resistor as fabricated to a desired lower value.

4. An adjustable resistor in accordance with claim 3 wherein at least one solder bridge connection is completed between a predetermined pair of said closely spaced bonding pads to lower the nominal value of resistance of said resistor as fabricated to a desired lower value.

5. An adjustable resistor in accordance with claim 3 wherein at least one conductive wire is bonded at opposite ends to different ones of a predetermined spaced pair of said bonding pads so as to short-circuit that part of the resistor body portion therebetween and, thereby, lower the nominal value of resistance of said resistor as fabricated to a desired value for a given circuit application.

6. An adjustable planar configured resistor comprising:

insulative support means;

a relatively thin layer of resistive material formed in a desired configuration on, and supported by, said support means, said resistive layer defining the main body portion of said resistor, and having at least two conductive terminals connected to end regions thereof for completing electrical connections to said main body portion, and

a plurality of discrete conductive bonding pads formed on and supported by said support means, each pad being in conductive contact with a different spaced site along the body portion of said resistor between at least said two terminals thereof, said bonding pads being of sufficient cross-section, and arranged on said support means such that at least selected adjacent ones of said pads are spaced sufficientl close, to allow selectively short-circuiting solder bridges and bonded interconnections to be formed between selected adjacent pairs thereof, after fabrication of the resistor, so as to lower the nominal resistance of said resistor as fabricated to a desired lower value.

7. An adjustable resistor in accordance with claim 6 wherein at least one solder bridge connection is completed between a predetermined pair of said closely spaced bonding pads to lower the nominal value of resistance of said resistor as fabricated to a desired lower value.

8. An adjustable resistor in accordance with claim 6 further comprising a plurality of short-circuiting shunts which are initially formed on said support means and connected between different spaced points along said body portion of said resistor, said shunts, when selectively opened, causing the nominal value of resistance of said resistor as fabricated to be increased, whereas a short-circuit connection when established between two selected ones of said bonding pads causes the resistance of said resistor as fabricated to be lowered.

9. An adjustable resistor in accordance with claim 8 wherein at least one of said short-circuiting conductive shunts is opened to increase the nominal resistance of said resistor as fabricated to a predetermined higher desired value.

10. An adjustable resistor in accordance with claim 8 wherein at least one short-circuit path is established between two selected bonding pads of said resistor so as to decrease the nominal value of resistance of said resistor as fabricated to a predetermined desired value.

11. An adjustable resistor in accordance with claim 8 wherein at least one of said short-circuiting conductive shunts is opened, and at least one short-circuit path is established between two of said bonding pads so as to adjust the nominal value of resistance of said resistor as fabricated to a desired final value on a selected side of said nominal value.

12. An adjustable planar configured, metallized resistor comprising:

insulative support means;

a relatively thin layer of resistive material formed in a desired configuration on and supported by said support means, said resistive layer defining the main body portion of said resistor, and having at least two conductive terminals connected to end regions thereof for completing electrical connections to said main body portion;

a plurality of discrete conductive bonding pads formed on and supported by said support means, each pad being in conductive contact with a different spaced site along the body portion of said resistor between at least said two terminals thereof, said bonding pads being of sufficient cross-section to allow conductive short-circuiting interconnections to be made between different selected pairs thereof, after fabrication of the resistor, whenever necessary to reduce the initial nominal value of resistance of said resistor to a lower desired value, and

a plurality of short-circuiting shunts initially formed on said support means and connected between different space points along said body portion of said resistor so as to initially respectively short out those segments of the resistor body portion disposed therebetween, said shunts, when selectively opened, causing the nominal value of the resistance of said resistor selectively as fabricated and subsequently adjusted to be increased by a predetermined magnitude, whereas said short-circuit connection when established between two selected ones of said bonding pads causes the then existing resistance of said resistor to be lowered by a predetermined magnitude.

13. An adjustable resistor in accordance with claim 12 wherein at least one of said short-circuiting conductive shunts is opened so that, in combination with at least said one short-circuit path also established between said two selected bonding pads, the nominal value of resistance of said resistor as fabricated is adjusted to a desired final value on a selected side of said nominal value.

14. A resistance adjustable electrical circuit comprising:

insulative support means;

an electrical circuit fabricated on at least one surface of said support means, including a resistance adjustable, planar configured resistor, said resistor comprising a relatively thin layer of resistive material formed in a desired configuration on, and supported by, said support means, said resistive layer defining the main body portion of said resistor, and having at least two conductive terminals connected to end regions thereof for completing electrical connections to said main body portion;

a plurality of discrete conductive bonding pads formed on and supported by said support means, each pad being in conductive contact with a different spaced site along the body portion of said resistor between at least said two terminals thereof, said bonding pads being of sufficient cross-section to allow conductive short-circuiting interconnections to be made between different selected pairs thereof, after fabrication of the resistor, whenever necessary to reduce the initial nominal value of resistance of said resistor to a lower desired value;

at least one conductive member interconnecting a selected pair of said bonding pads so as to provide a short-circuit path around that part of the resistor body portion therebetween and, thereby, lower the nominal value of resistance of said resistor as fabricated to a desired value for a given circuit application, and

a plurality of short-circuiting shunts initially formed on said support means and connected between different spaced points along said body portion of said resistor, said shunts, when selectively opened, causing the nominal value of resistance of said resistor selectively as fabricated and subsequently adjusted to be increased by a predetermined magnitude, whereas said short-circuit path upon being established between said two selected ones of said bonding pads causes the then existing resistance of said resistor to be lowered by a predetermined magnitude.

15. A resistance adjustable electrical circuit in accordance with claim 14 wherein at least one of said short-circuiting conductive shunts is opened so that, in combination with at least said one short-circuit path also established between said two selected bonding pads, the nominal value of of resistance of said resistor as fabricated is adjusted to a desired final value on a selected side of said nominal value.

16. A method of adjusting the resistance of a planar configured, and insulatively supported resistor having two terminating ends, said method comprising the steps of:

forming a plurality of discrete conductive bonding pads in a predetermined array on a common insulative support with the resistor, and arranging each of said bonding pads so as to be in conductive contact with a different spaced site along the body portion of said resistor between said terminating ends thereof, said formed bonding pads being of sufficient cross-section and closely spaced in at least one predetermined cluster so as to facilitate conductive short-circuiting interconnections to be made between different selected pairs thereof, after fabrication of the resistor, selectively by solder bridges and bonded wiring, whenever necessary to reduce the initial nominal value of resistance of said resistor to a lower desired value, and

interconnecting at least two of said plurality of bonding pads with an auxiliary conductive member so as to provide a short-circuit path around that part of the resistor body portion therebetween and, thereby, lower the nominal value of resistance of said resistor as fabricated by a desired predetermined magnitude for a given circuit application.

17. A method in accordance with claim 16 wherein said interconnection is effected by forming a solder bridge between said selected pair of bonding pads.

18. A method in accordance with claim 17 wherein said cluster of bonding pads are formed at a location remote from the body portion of said resistor, and further comprising the step of:

interconnecting the respective bonding pads to different ones of the spaced sites along said resistor body portion by forming separate conductive paths therebetween on said insulative support.

19. A method in accordance with claim 16 wherein said bonding pads are respectively formed at different spaced sites on said body portions of said resistor.

20. A method in accordance with claim 16 further comprising the step of:

forming a plurality of short-circuiting shunts on said common insulative support, said shunts extending between different spaced points along the body portion of said resistor so as to initially respectively short out those segments of the resistor body portion disposed therebetween, said shunts, when selectively opened, causing the nominal value of resistance of said resistor selectively as fabricated and subsequently adjusted to be increased by a predetermined magnitude, whereas said short-circuit connection upon being established between said two selected ones of said bonding pads effects the lowering of the resistance of said resistor by a predetermined magnitude.

21. A method in accordance with claim 20 further comprising the step of:

opening at least a selected one of said short-circuiting conductive shunts so as to adjust the nominal value of resistance of said resistor, in conjunction with said established short-circuit path, to a desired final value on a selected side of said nominal value.

22. A method in accordance with claim 21 wherein the step of establishing at least one short-circuit path between two selected ones of said bonding pads is effected by stitch-bonding opposite ends of a fine gauge wire to different ones of said selected pair of bonding pads.

23. A method of fabricating an adjustable planar configured resistor having two terminating ends, comprising the steps of:

forming a resistive material layer on the surface of an insulative member in accordance with a predetermined pattern, said resistive layer comprising the main body portion of said resistor;

forming a plurality of discrete conductive bonding pads in a predetermined array on said insulative member, and arranging each of said bonding pads so as to be in conductive contact with a different spaced site along the body portion of said resistor between said terminating ends thereof, said bonding pads being of sufficient cross-section to allow conductive short-circuiting interconnections to be made between different selected pairs thereof, after fabrication of the resistor, whenever necessary to reduce the initial nominal value of resistance of said resistor to a lower desired value, and

forming a plurality of short-circuiting shunts on said insulative member, said shunts extending between different spaced points along the body portion of said resistor so as to initially respectively short out those segments of the resistor body portion disposed therebetween, said shunts, when selectively opened, causing the nominal value of resistance of said resistor selectively as fabricated and subsequently adjusted to be increased by a predetermined magnitude, whereas a short-circuit connection when established between any two selected ones of said bonding pads will cause the resistance of said resistor to be lowered by a predetermined magnitude.

24. A method in accordance with claim 23 comprising the further step of:

conductively interconnecting at least two of said spaced array of bonding pads with an auxiliary conductive member so as to provide a short-circuit path around that part of the resistor body portion therebetween and, thereby, lower the nominal value of resistance of said resistor as fabricated by a desired predetermined magnitude for a given circuit application.

25. A method in accordance with claim 23 further comprising the step of:

opening at least a selected one of said short-circuiting shunts so as to increase the value of resistance then exhibited by said resistor by a predetermined magnitude to a higher desired value.

26. A method in accordance with claim 23 further comprising the steps of:

opening at least a selected one of said short-circuiting shunts, and

establishing at least one short-circuit connection, and between two selected ones of said bonding pads, after fabrication of said resistor, to effect an adjustment of an initial value of resistance of said resistor by a predetermined incremental magnitude, in a predetermined direction, to produce a desired final value of resistance on the selected side of the initial value.