DUAL THIN FILM PRECISION RESISTANCE TRIMMING

• US 20100073122A1
• Filed: 09/17/2009
• Published: 03/25/2010
• Est. Priority Date: 09/17/2008
• Status: Active Grant

• Current Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV), STMicroelectronics SAS (STMicroelectronics NV)
• Inventors: Niu, Chengyu, Arnoux, Michel, Dumont-Girard, Pascale, Wang, Fuchao, Le Neel, Olivier
• Granted Patent: US 8,242,876 B2
• Time in Patent Office: Days
• US Class Current: 338/25
• CPC Class Codes: H01C 17/265 by chemical or thermal treatment, e.g. oxydation, reduction, annealing etching H01C17/2416
• CPC Class Codes: H01L 23/345 Arrangements for heating thermal treatment apparatus H01L21/00
• CPC Class Codes: H01L 23/5228 Resistive arrangements or effects of, or between, wiring layers other resistive arrangements H01L23/647
• CPC Class Codes: H01L 27/016 Thin-film circuits
• CPC Class Codes: H01L 27/0688 Integrated circuits having a three-dimensional layout
• CPC Class Codes: H01L 28/20 Resistors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: Y10T 29/49087 with envelope or housing

Abstract

A trimmable resistor for use in an integrated circuit is trimmed using a heater. The heater is selectively coupled to a voltage source. The application of voltage to the heater causes the heater temperature to increase and produce heat. The heat permeates through a thermal separator to the trimmable resistor. The resistance of the trimmable resistor is permanently increased or decreased when the temperature of the resistor is increased to a value within a particular range of temperatures.

Claims

1. A trimmable resistance structure, comprising:

an integrated semiconductor circuit having components in a silicon substrate;

a resistive structure composed of a material whose resistance is permanently changeable by application of heat thereto, the resistive structure being part of the integrated circuit;

a dielectric disposed adjacent to the resistive structure;

a heater disposed adjacent to the dielectric, the dielectric being disposed so as to separate the heater from the resistive structure; and

a switch coupled between the heater and a voltage supply.

2. The structure of claim 1 wherein the resistive structure, the heater, and the dielectric material are thin films.

3. The structure of claim 1 wherein the voltage supply is capable of sourcing a voltage sufficient to increase the temperature of the heater to at least 450°

C.

4. The structure of claim 1 wherein the heater is in a serpentine shape.

5. The structure of claim 1 wherein the dielectric includes Si₃N₄.

6. The structure of claim 5 wherein the resistive structure includes CrSi.

7. A resistor trimming method, comprising:

applying a voltage to a heater through a switch;

heating a resistive structure adjacent to the heater;

permanently changing the resistance value of the resistive structure during the heating step; and

removing the voltage from the heater.

8. The method of claim 7 wherein the resistive structure, the heater, and the dielectric material are thin films.

9. The method of claim 7 wherein applying the voltage comprises applying a voltage pulse to the heater.

10. The method of claim 7 wherein heating the resistive structure includes heating the resistive structure in excess of 450°

C.

11. The method of claim 10 wherein heating the resistive structure decreases the resistance of the resistive structure.

12. A circuit, comprising:

an amplifier;

a trimmable thin film resistor electrically coupled to the amplifier;

a thin film heater thermally coupled to the trimmable thin film resistor;

a transistor electrically coupled to the thin film heater to selectively permit current to increase a temperature of the thin film heater; and

a thin film thermal separator disposed between the trimmable thin film resistor and the thin film heater.

13. The circuit of claim 12 wherein the thin film heater is a thin film resistor.

14. The circuit of claim 13 wherein the resistance of the thin film heater is less than the resistance of the trimmable thin film resistor.

15. The circuit of claim 12 wherein the resistance of the trimmable thin film resistor permanently changes with exposure to a temperature within a range of temperatures.

16. The circuit of claim 15 wherein the range of temperatures includes 450°

C. to 850°

C.

17. The circuit of claim 12 wherein the thin film thermal separator is a dielectric.

18. The circuit of claim 17 wherein the thin film thermal separator includes Si₃N₄.

19. The apparatus of claim 12 wherein the trimmable thin film resistor includes CrSi.