Resistor device and method of manufacturing the same

• US 8,203,422 B2
• Filed: 11/17/2008
• Issued: 06/19/2012
• Est. Priority Date: 11/22/2007
• Status: Active Grant

• Current Assignee: KOA Corporation
• Original Assignee: KOA Corporation
• Inventors: Naito, Takashi, Nakamura, Akihiko
• Primary Examiner(s): Lee, Kyung
• Application Number:
  US12/272,137
• Publication Number:
  US 20090134967A1
• Time in Patent Office: 1,310 Days
• Field of Search: 338/307, 338/308, 338/309, 338/333, 338/334
• US Class Current: 338/308
• CPC Class Codes: H01C 1/012 the base extending along and imparting rigidity or reinforcement to the resistive element H01C1/016 takes precedence; the resistive element being formed in two or more coils or loops as a spiral, helical or toroidal winding H01C3/18, H01C3/20; the resistive element being formed as one or more layers or coatings on a base H01C7/00
• CPC Class Codes: H01C 17/06533 composed of oxides
• CPC Class Codes: H01C 17/22 adapted for trimming
• CPC Class Codes: Y10T 29/49099 Coating resistive material on a base

Abstract

To provide a glazed metal film resistor device excellent in TCR characteristics with using an economical base body containing glass by reducing affection to TCR characteristics caused by glass contained in the base body. The resistor device comprises base body 11 containing glass, first protective film 12, which does not contain glass, formed on a surface of base body 11, and thick film resistor 13 formed on first protective film 12. By forming first protective film 12 on a surface of base body 11 containing glass and insulating base body 11 containing glass against thick film resistor 13 of ruthenium oxide as primary component, affection of glass contained in base body 11 to thick film resistor 13 of ruthenium oxide can be suppressed, and change of TCR value from original value of thick film resistor itself can be suppressed.

Claims

1. A resistor device comprising:

an insulative base body containing glass;

a first protective film, which does not contain glass, and which comprises a metal oxide film, formed on a surface of said base body; and

a thick film resistor containing conductive material and glass formed on said first protective film;

wherein said glass contained in said insulative base body is prevented from diffusing into said thick film resistor.

2. The resistor device according to claim 1, wherein thickness of said first protective film is 0.1 μ

m or more.

3. The resistor device according to claim 1, wherein said thick film resistor comprises RuO₂ as primary component.

4. The resistor device according to claim 1, wherein said first protective film comprises one or more of metal oxide selected from SnO₂, Bi₂O₃, PbO, AgO, NiO, SeO₂, HfO, Y₂O₃, ZnO, MgO, InO₂, SrO, Ta₂O₅, TeO₂, CdO, SiO₂, GeO₂, GaO₂, Al₂O₃, ZrO₂, BaO, and CaO.

5. The resistor device according to claim 1, wherein said first protective film comprises a metal oxide film containing tin oxide as primary component and nickel oxide or bismuth oxide.

6. The resistor device according to claim 1, wherein said base body is a columnar ceramic insulator, which comprises alumina and glass.

7. The resistor device according to claim 6, wherein ratio of alumina/glass of said base body is 50/50, or 80/20.

8. The resistor device according to claim 1, wherein said resistor device has resistance value of higher resistance value region ranging 100 kΩ

to 10 GΩ

.

9. A method of manufacturing a resistor device comprising:

preparing an insulative base body containing glass;

forming a first protective film of metal oxide on a surface of said base body;

coating a surface of said first protective film with thick film resistor paste containing conductive material and glass, and firing said paste to form a thick film resistor, wherein said first protective film prevents said glass contained in said insulative base body from diffusing into said thick film resistor;

fitting electrode caps on at both ends of said base body, on which said thick film resistor is formed, and connecting said caps to said thick film resistor; and

trimming said thick film resistor to adjust resistance value of said resistor device.

10. The method according to claim 9, wherein said first protective film is formed by;

atomizing solution containing metal chloride as primary component and metal dissolved in hydrochloric acid to said base body; and

heating said base body to form said first protective film, which contains metal oxide as primary component and other metal oxide as additive component.

11. The method according to claim 10, wherein said solution contains tin chloride as primary component and nickel or bismuth dissolved in hydrochloric acid.

12. The method according to claim 9, wherein said base body is a columnar ceramic insulator, which comprises alumina and glass.

13. The method according to claim 12, wherein ratio of alumina/glass of said base body is 50/50, or 80/20.

14. The method according to claim 9, wherein said thick film resistor comprises RuO₂ as primary component.

15. The method according to claim 9, wherein said first protective film comprises a metal oxide film containing tin oxide as primary component and nickel oxide or bismuth oxide.

16. The method according to claim 9, wherein said resistor device has resistance value of higher resistance value region ranging 100 kΩ

to 10 GΩ

.