MULTI-LAYER VIA-LESS THIN FILM RESISTOR

• US 20120049324A1
• Filed: 08/24/2010
• Published: 03/01/2012
• Est. Priority Date: 08/24/2010
• Status: Active Grant

• Current Assignee: Stmicroelectronics Pte Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Le Neel, Olivier, Leung, Calvin
• Granted Patent: US 8,436,426 B2
• Time in Patent Office: Days
• US Class Current: 257/537
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76852 the layer also covering the sidewalls of the conductive structure
• CPC Class Codes: H01L 2221/1078 Multiple stacked thin films not being formed in openings in dielectrics
• CPC Class Codes: H01L 23/5228 Resistive arrangements or effects of, or between, wiring layers other resistive arrangements H01L23/647
• CPC Class Codes: H01L 28/20 Resistors
• CPC Class Codes: H01L 28/24 with an active material comprising a refractory, transition or noble metal, metal compound or metal alloy, e.g. silicides, oxides, nitrides
• 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

Abstract

The present disclosure is directed to a thin film resistor having a first resistor layer having a first temperature coefficient of resistance and a second resistor layer on the first resistor layer, the second resistor layer having a second temperature coefficient of resistance different from the first temperature coefficient of resistance. The first temperature coefficient of resistance may be positive while the second temperature coefficient of resistance is negative. The first resistor layer may have a thickness in the range of 50 and 150 angstroms and the second resistor layer may have a thickness in the range of 20 and 50 angstroms.

Claims

1. A thin film resistor, comprising:

a first resistor layer having a first temperature coefficient of resistance; and

a second resistor layer on the first resistor layer, the second resistor layer having a second temperature coefficient of resistance different from the first temperature coefficient of resistance.

2. The thin film resistor of claim 1 wherein the first resistor layer and the second resistor layer form the thin film resistor having a third temperature coefficient of resistance that is in the range of positive 20 parts per million per degrees Celsius and negative 20 parts per million per degrees Celsius.

3. The thin film resistor of claim 1 wherein the first temperature coefficient of resistance is positive and the second temperature coefficient of resistance is negative.

4. The thin film resistor of claim 1 wherein the first resistor layer has a thickness in the range of 50 and 150 angstroms and the second resistor layer has a thickness in the range of 20 and 50 angstroms.

5. The thin film resistor of claim 1 wherein the first resistor layer is less than 50 angstroms in thickness and the second resistor layer is less than 50 angstroms in thickness.

6. The thin film resistor of claim 1, further comprising a third resistor layer on the second resistor layer and the third resistor layer having a fourth temperature coefficient of resistance.

7. A method, comprising:

forming a thin film resistor on a substrate, the forming comprising;

forming a first resistor layer on the substrate, the first resistor layer having a first composition of a plurality of elements and having a first thickness less than 200 angstroms; and

forming a second resistor layer on the first resistor layer, the second resistor layer having a second composition of the plurality of elements and having a second thickness that is less than 150 angstroms.

8. The method of claim 7 further comprising forming the first composition from a first target in a sputter deposition chamber and forming the second composition from a second target in the sputter deposition chamber.

9. The method of claim 8 wherein the first target is 55% chromium and the second target is 85% chromium.

10. The method of claim 7 wherein the first and second compositions are different alloys of chromium silicon.

11. The method of claim 7 wherein the first resistor layer has a first temperature coefficient of resistance and the second resistor layer has a second temperature coefficient of resistance.

12. The method of claim 10 wherein the first temperature coefficient of resistance is positive and the second temperature coefficient of resistance is negative.

13. The method of claim 7, further comprising forming a third resistor layer on the second resistor layer, the third resistor layer having a third composition of the plurality of elements.

14. An integrated circuit, comprising:

a substrate;

a first interconnect having a first conductor layer on the substrate and a second conductor layer on the first conductor, the first interconnect having a first sidewall transverse to the substrate;

a second interconnect spaced from the first interconnect, the second interconnect having the first conductor layer on the substrate and the second conductor layer on the first conductor layer, the second interconnect having a second sidewall transverse to the substrate;

a resistive element having a plurality of resistive layers formed on the substrate between the first and second interconnects and on the first and second sidewalls of the first and second interconnects, the plurality of resistive layers comprising;

a first resistive layer electrically connecting the first conductor layers of the first and second interconnects; and

a second resistive layer formed on the first resistive layer.

15. The integrated circuit of claim 14 wherein the first resistive layer has a first temperature coefficient of resistance and the second resistive layer has a second temperature coefficient of resistance different than the first temperature coefficient of resistance.

16. The integrated circuit of claim 14 wherein the first resistive layer and the second resistive layer are different chromium silicon alloys.

17. The integrated circuit of claim 14 wherein the first temperature coefficient of resistance is positive and the second temperature coefficient of resistance is negative.