Method of forming trimmable resistors

• US 6,539,613 B1
• Filed: 12/28/1999
• Issued: 04/01/2003
• Est. Priority Date: 06/12/1998
• Status: Expired due to Fees

• Current Assignee: Intermedics Incorporated
• Original Assignee: Intermedics Incorporated
• Inventors: Ulmer, Kenneth R.
• Primary Examiner(s): Arbes, Carl J.
• Assistant Examiner(s): TRINH, MINH N
• Application Number:
  US09/473,281
• Time in Patent Office: 1,190 Days
• Field of Search: 296/13, 296/20, 296/21, 298/42, 298/52, 296/101, 296/14, 338/258, 338/295, 338/308, 338/309, 338/310, 338/312, 338/320, 338/270, 338/275, 338/226, 427/96, 427/101-103, 427/523-526
• US Class Current: 29/620
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H05K 1/092 Dispersed materials, e.g. conductive pastes or inks
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/0919 Exposing inner circuit layers or metal planes at the side edge of the PCB or at the walls of large holes shielding provided by an inner layer of PCB H05K2201/0723
• CPC Class Codes: H05K 2201/09563 Metal filled via plated through-hole filled with insulating material H05K2201/0959
• CPC Class Codes: H05K 2203/171 Tuning, e.g. by trimming of printed components or high frequency circuits
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/403 Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof H05K3/4092 takes precedence
• CPC Class Codes: H05K 3/4053 by thick-film techniques
• CPC Class Codes: Y10T 29/49082 Resistor making
• CPC Class Codes: Y10T 29/49089 Filling with powdered insulation
• CPC Class Codes: Y10T 29/49099 Coating resistive material on a base
• CPC Class Codes: Y10T 29/49101 Applying terminal

Abstract

A method of forming trimmable resistors, resistor ray be embedded into a substrate. A portion of the resistor may be exposed, by segmenting the substrate, so that the resistor may be trimmed to a desired resistance level. Alternatively, a portion of a resistor may be embedded into a substrate, with another portion of the resistor being disposed on the outer surface of the substrate. The portion of the resistor on the outer surface may be trimmed to adjust the resistance of the resistor to a desired level.

Claims

1. A method of forming a resistor comprising:

providing a substrate having an opening therein and having an outer surface;

disposing a first portion of electrically resistive material in the opening of the substrate;

disposing a second portion of electrically resistive material on the outer surface of the substrate;

segmenting the substrate through the opening and the first portion; and

trimming the second portion of the electrically resistive material to form a resistor having a given resistance.

2. The method, as set forth in claim 1, wherein the acts are performed in the recited order.

3. The method, as set forth in claim 1, wherein disposing the first portion and disposing the second portion comprise firing the electrically resistive material.

4. The method, as set forth in claim 1, wherein trimming the second portion comprises using a laser to remove a portion of the second portion of electrically resistive material.

5. The method of claim 1, wherein segmenting the substrate includes removing some of the first portion.

6. The method of claim 5, wherein removing some of the first portion includes trimming the first portion to form the resistor to a given resistance.

7. The method of claim 1, wherein segmenting the substrate includes exposing the first portion.

8. The method of claim 7, wherein exposing the first portion includes trimming the first portion.

9. A method of forming a resistor, comprising:

providing an opening in a substrate;

disposing a first electrically resistive material in the opening;

disposing a second electrically resistive material on a surface of the substrate in contact with the first electrically resistive material;

segmenting the substrate through the opening to expose a portion of the first electrically resistive material; and

trimming at least one of the second electrically resistive material and the exposed portion of the first electrically resistive material.

10. The method of claim 9, wherein segmenting includes sawing the substrate.

11. The method of claim 9, wherein providing an opening includes providing a first substrate layer, a second substrate layer and an intermediate substrate layer between the first substrate layer and the second substrate layer;

and providing the opening in the intermediate substrate layer.

12. The method of claim 11, wherein disposing the second electrically resistive material includes disposing the second electrically resistive material on a surface of one of the first substrate layer and the second substrate layer.

13. The method of claim 12, wherein trimming includes lazing the at least one of the second electrically resistive material and the exposed portion of the first electrically resistive material.

14. The method of claim 9, wherein trimming includes lazing the at least one of the second electrically resistive material and the exposed portion of the first electrically resistive material.

15. The method of claim 9 wherein trimming at least one of the exposed portion of the first electrically resistive material and the second resistive material includes trimming so that the first and second electrically resistive material have a desired resistance.

16. The method of claim 9, wherein providing the opening includes covering the opening with an upper substrate layer and a lower substrate layer.

17. The method of claim 9, wherein providing the opening includes providing a cavity open to a peripheral surface of the substrate.

18. A method of forming a resistor in a cardiac stimulator, comprising:

providing a substrate that has an opening and an outer surface in a cardiac stimulator;

disposing a first electrically resistive material in the opening;

disposing a second electrically resistive material on the outer surface and in contact with the first electrically resistive material;

segmenting the substrate through the opening and the first electrically resistive material; and

trimming at least one of the first electrically resistive material and the second resistive material to form a resistor having a given resistance.