Chip resistor and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9911524-B2
Application number	US-201615006642-A
Country	US
Kind code	B2
Filing date	Jan 26, 2016
Priority date	Feb 17, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A chip resistor includes: a resistor body having a front surface and a mounting surface which face in opposite directions; a pair of electrodes which are disposed on both sides of the resistor body with the resistor body sandwiched therebetween and are in electrical conduction with the resistor body; and a protective film covering a portion of the resistor body, wherein a plurality of grooves, which does not penetrate through the resistor body, is formed in the front surface of the resistor body.

First claim

What is claimed is:

1. A chip resistor comprising:
a resistor body having a front surface and a mounting surface which face in opposite directions;
a pair of electrodes which are disposed on both sides of the resistor body with the resistor body sandwiched therebetween and are in electrical conduction with the resistor body; and
a protective film covering a portion of the resistor body,
wherein a plurality of grooves, which does not penetrate through the resistor body, is formed in the front surface of the resistor body.

2. The chip resistor of claim 1 , wherein a direction of the plurality of grooves is a direction perpendicular to a direction of current flowing through the resistor body.

3. The chip resistor of claim 1 , wherein an interval between the plurality of grooves is 50 to 100 μm.

4. The chip resistor of claim 1 , wherein the resistor body has a serpentine shape when viewed from top.

5. The chip resistor of claim 1 , wherein a thickness of the resistor body is 50 to 150 μm.

6. The chip resistor of claim 1 , wherein the resistor body is made of an alloy containing Cu, Mn and Ni.

7. The chip resistor of claim 1 , wherein the pair of electrodes covers a portion of each of the resistor body and the protective film.

8. The chip resistor of claim 1 , wherein the pair of electrodes includes an inner electrode which is in electrical conduction with the resistor body and covers a portion of the protective film, an intermediate electrode covering the inner electrode, and an outer electrode covering the intermediate electrode.

9. The chip resistor of claim 8 , wherein the inner electrode is made of a Ni—Cr alloy.

10. The chip resistor of claim 8 , wherein the intermediate electrode and the outer electrode are formed from a plating layer.

11. The chip resistor of claim 10 , wherein the outer electrode is formed from a Sn plating layer.

12. The chip resistor of claim 10 , wherein the intermediate electrode includes a first intermediate electrode covering the inner electrode and a second intermediate electrode covering the first intermediate electrode.

13. The chip resistor of claim 12 , wherein the first intermediate electrode is formed from a Cu plating layer.

14. The chip resistor of claim 12 , wherein the second intermediate electrode is formed from a Ni plating layer.

15. The chip resistor of claim 1 , wherein the protective film is made of a thermosetting resin.

16. The chip resistor of claim 15 , wherein the protective film is made of a polyimide resin.

17. The chip resistor of claim 1 , further comprising a substrate having a main surface and a mounting surface which face in opposite directions,
wherein the resistor body is mounted on the substrate under a state where the mounting surface of the resistor body and the mounting surface of the substrate face each other.

18. The chip resistor of claim 17 , wherein the substrate is an electrical insulator.

19. The chip resistor of claim 18 , wherein the substrate is made of alumina.

20. The chip resistor of claim 18 , wherein the substrate is made of a glass epoxy resin.

21. The chip resistor of claim 20 , wherein the resistor body is mounted on the substrate under a state where the resistor body is buried in the substrate.

22. The chip resistor of claim 17 , further comprising an adhesive layer sandwiched between the mounting surface of the substrate and the mounting surface of the resistor body.

23. The chip resistor of claim 22 , wherein the adhesive layer is an electrical insulator.

24. The chip resistor of claim 23 , wherein the adhesive layer contains an epoxy resin.

25. A method for manufacturing a chip resistor, comprising:
preparing a sheet resistor body which includes a plurality of resistor body regions and has a front surface and a mounting surface which face in opposite directions;
forming a plurality of grooves for resistance adjustment for each of the resistor body regions, the plurality of grooves being formed in front surfaces of the plurality of resistor body regions and not penetrating through the resistor body regions;
forming a protective film body covering a portion of the plurality of resistor body regions in the front surface of the sheet resistor body;
forming a conductive layer in an exposed portion of the plurality of resistor body regions, which is not covered by the protective film body, in the front surface of the sheet resistor body; and
dividing the sheet resistor body into segments for the resistor body regions to form a pair of inner electrodes, which are in electrical conduction with the resistor body regions, on both sides of each of the resistor body regions with the resistor body regions sandwiched between the inner electrodes.

26. The method of claim 25 , wherein the act of forming a plurality of grooves includes forming a trimming groove for each of the resistor body regions, the trimming groove penetrating through the resistor body region.

27. The method of claim 25 , wherein the act of forming a plurality of grooves includes forming the plurality of grooves by means of a laser trimming device.

28. The method of claim 27 , wherein the act of forming a plurality of grooves includes forming the plurality of grooves for each of a plurality of sections set in each of the resistor body regions.

29. The method of claim 28 , wherein the act of forming a plurality of grooves includes forming the plurality of grooves in an order from a section located in an outer side of the resistor body region toward a section located in an inner side of the resistor body region.

30. The method of claim 29 , wherein the act of forming a plurality of grooves includes forming the plurality of grooves alternately in an order of a section located between the center of the resistor body region and one of the pair of inner electrodes and a section located between the center of the resistor body region and the other of the pair of inner electrodes.

31. The method of claim 25 , wherein the act of forming a conductive layer includes forming the conductive layer by means of deposition or printing.

32. The method of claim 31 , wherein the deposition is a sputtering.

33. The method of claim 25 , further comprising forming an intermediate electrode covering the pair of inner electrodes and an outer electrode covering the intermediate electrode for each of the segments.

34. The method of claim 33 , wherein the act of forming an intermediate electrode and an outer electrode includes forming the intermediate electrode and the outer electrode by means of plating.

35. The method of claim 25 , further comprising bonding a sheet substrate to the mounting surface of the sheet resistor body.

36. The method of claim 35 , wherein the act of bonding a sheet substrate includes bonding the sheet substrate by applying an adhesive made of an epoxy resin to the mounting surface of the sheet resistor body or by disposing an adhesive sheet made of a glass epoxy resin on the mounting surface of the sheet resistor body.

Assignees

• Rohm Co Ltd

Inventors

• Tanaka Kosaku
• Nozaka Takashi

Classifications

• H01C17/242

  by laser · CPC title

• H01C7/003

  Thick film resistors · CPC title

• H01C7/20 Primary

  the resistive layer or coating being tapered · CPC title

• H01C1/142

  the terminals or tapping points being coated on the resistive element · CPC title

• H01C17/006

  adapted for manufacturing resistor chips · CPC title