CN-113945308-B - Mechanical stress sensing and compensation on a substrate

Abstract

The application discloses mechanical stress sensing and compensation on a substrate. In the depicted example, one circuit 500 includes an analog front end 403, the analog front end 403 being arranged to generate an analog stress compensation signal in response to an analog signal to be compensated and a first axis stress sense signal (e.g., vsense_x). The analog front end 403 may include a first precision component (e.g., rsense xa) disposed on the piezoelectric material 501 and arranged to generate an analog signal to be compensated (e.g., from 510) that is affected by stress applied in the piezoelectric material 501, and a directional stress sensor 440 disposed on the piezoelectric material 501 and coupled to the first precision component. The directional stress sensor 440 is arranged to generate a first axis sensing signal in response to a longitudinal resultant of stresses applied in the piezoelectric material 501. The compensation circuit 520 is arranged to generate a compensation output signal in response to the compensation analog signal and the analog signal to be compensated.

Inventors

• U. Nurmetov
• R. P. Breedlow
• B. Halon
• FORMENTI JOSE ANTONIO VIEIRA
• M. Shi Zelong
• T. B. Fritz

Assignees

• 德克萨斯仪器股份有限公司
• 德克萨斯仪器股份有限公司

Dates

Publication Date

20260421

Application Date

20210719

Priority Date

20200717

Claims (20)

1. 1. A circuit, comprising: A piezoelectric material having a crystal axis, a first piezoresistive coefficient having a first axis orientation relative to the crystal axis orientation, and a second piezoresistive coefficient having a second axis orientation different from the first axis orientation; an analog front end having an analog front end output, wherein the analog front end is arranged to generate an analog compensation signal at the analog front end output in response to an electrical signal to be compensated and a first axis stress sensing signal, and wherein the analog front end comprises: a precision member arranged on the piezoelectric material and arranged to generate the electric signal to be compensated influenced by stress applied in the piezoelectric material, and A first axial stress sensor disposed on the piezoelectric material and coupled to the precision component, wherein the first axial stress sensor comprises a first axial stress sensing resistor coupled in series with a second axial stress sensing resistor, the first axial stress sensing resistor comprising a first axial conductor disposed along the first axial orientation, the second axial stress sensing resistor comprising a second axial conductor disposed along the second axial orientation, wherein a ratio of resistances of the first axial stress sensing resistor to the second axial stress sensing resistor is proportional to a ratio of the first piezoresistive coefficient to the second piezoresistive coefficient, wherein the first axial stress sensor is arranged to generate a first axial sensing signal in response to a first axial force of stress applied in the piezoelectric material, and A compensation circuit comprising a first input coupled to the analog front end output, a second input coupled to an output of the analog circuit to be compensated, and arranged to generate a compensation output signal at the analog front end output, wherein the compensation output signal is generated by the compensation circuit in response to the analog compensation signal and the output signal of the analog circuit to be compensated.
2. 2. The circuit of claim 1, wherein the precision component comprises a calibrated resistor.
3. 3. The circuit of claim 1, wherein the analog front end further comprises a second axial force sensor disposed on the piezoelectric material, the second axial force sensor being arranged to generate a second axial sensing signal in response to a second axial resultant of stresses applied in the piezoelectric material.
4. 4. A circuit according to claim 3, wherein the analog front end further comprises a third axis stress sensor arranged on the piezoelectric material, the third axis stress sensor being arranged to generate a third axis sensing signal in response to a third axis resultant of the stresses applied in the piezoelectric material.
5. 5. The circuit of claim 1, wherein the first axis stress sensor comprises a first terminal coupled to a first power rail and a second terminal coupled to a first terminal of the precision component, wherein a second terminal of the precision component is coupled to a second power rail.
6. 6. The circuit of claim 5, wherein the first axis stress sensor is a first axis stress sensor, the precision component is a first precision component, the circuit further comprising a second precision component and a second first axis stress sensor, wherein the second first axis stress sensor comprises a first terminal coupled to the second power rail and a second terminal coupled to a first terminal of the second precision component, and wherein the second precision component further comprises a second terminal coupled to the first power rail.
7. 7. The circuit of claim 6, wherein the first axis stress sensor, the second first axis stress sensor, the first precision component, and the second precision component are arranged in a wheatstone bridge, wherein the first axis sense signal is a first axis sense signal differential signal having a first end generated at the second terminal of the first axis stress sensor and a second end generated at the first terminal of the second first axis stress sensor.
8. 8. The circuit of claim 7, comprising an amplifier and a feedback resistor to convert the first axis sense signal differential signal to a first axis sense signal single ended signal.
9. 9. The circuit of claim 5, wherein a portion of the precision component is located between a portion of the first axis stress sensing resistor in series with the second axis stress sensing resistor.
10. 10. The circuit of claim 5, wherein the compensation circuit comprises a DSP.
11. 11. The circuit of claim 1, wherein the compensation circuit comprises a second output coupled to the analog circuit to be compensated, wherein the compensation circuit is arranged to generate a compensation feedback signal at the second output in response to the analog compensation signal.
12. 12. The circuit of claim 1, wherein the analog front end comprises at least one operational amplifier arranged to control a current coupled to generate the analog compensation signal in response to the precision component.
13. 13. The circuit of claim 12, wherein the at least one operational amplifier is arranged to generate an amplified analog compensation signal in response to a ratio of a value of the first axis stress sensor to a value of the precision component.
14. 14. The circuit of claim 1, wherein the analog front end comprises at least one current source arranged to generate a source current, wherein the analog compensation signal is generated in response to the source current and in response to a difference between the precision component and the first axis stress sensor.
15. 15. The circuit of claim 1, wherein the analog front end further comprises a second axial force sensor arranged to generate a second axial sense signal in response to a second axial resultant of stresses applied in the piezoelectric material, and wherein the compensation circuit is arranged to generate a combined analog compensation signal in response to the first axial sense signal and the second axial sense signal, and wherein the first axial sense signal and the second axial sense signal are current signals.
16. 16. The circuit of claim 15, comprising an analog circuit having an output reference node, wherein the first and second axis sense signals are injected into the output reference node of the analog circuit.
17. 17. A system, comprising: A piezoelectric material having a crystal axis, a first piezoresistive coefficient having a first axis orientation relative to the crystal axis orientation, and a second piezoresistive coefficient having a second axis orientation different from the first axis orientation; A precision component formed in a first location on the piezoelectric material, wherein the precision component includes a performance parameter affected by a stress applied in the piezoelectric material; A first stress sensor formed in a second location on the piezoelectric material, the first stress sensor coupled to the precision component; A second stress sensor formed in a third location on the piezoelectric material, the second stress sensor coupled to the precision component, and A processor coupled to the precision component, the first stress sensor, the second stress sensor, and arranged to generate a compensation amount in response to the output of the first stress sensor and the output of the second stress sensor, and in response to the first position, the second position, and the third position, wherein the compensation amount is applied to the precision component to compensate an output signal of the precision component affected by the performance parameter.
18. 18. The system of claim 17, wherein the processor is arranged to generate the compensation amount in response to a stress gradient propagating through the first, second and third locations of the piezoelectric material, wherein at least one value of stress gradient at the first location is determined in response to a first indication of at least one stress vector received from the first stress sensor and in response to a second indication of at least one stress vector received from the second stress sensor.
19. 19. A method, comprising: Disposing a precision component on a piezoelectric material, wherein the piezoelectric material has a crystal axis, a first piezoresistive coefficient having a first axis orientation relative to the crystal axis, and a second piezoresistive coefficient transverse to the crystal axis, wherein the precision component comprises a performance parameter affected by stress exerted in the piezoelectric material; Disposing a first axis stress sensor on the piezoelectric material and electrically coupled to the precision component, wherein the first axis stress sensor comprises a first axis stress sensing resistor coupled in series with a second axis stress sensing resistor, the first axis stress sensing resistor comprising a first axis conductor disposed along the crystal axis, the second axis stress sensing resistor comprising a second axis conductor disposed transverse to the crystal axis, wherein a ratio of resistances of the first axis stress sensing resistor to the second axis stress sensing resistor is proportional to a ratio of the first piezoresistive coefficient to the second piezoresistive coefficient; Generating a first axis sensing signal by the first axis stress sensor in response to a first axis resultant force of stress applied in the piezoelectric material, and An analog compensation signal is generated by the compensation circuit in response to the analog signal received from the circuit to be compensated and the first axis sensing signal.
20. 20. The method of claim 19, further comprising calibrating the precision component to limit a current of the first axis stress sensor to reduce an effect of stress applied in the piezoelectric material on the performance parameter of the circuit to be compensated.

Description

Mechanical stress sensing and compensation on a substrate Background Mechanical stresses can affect the physical dimensions and performance of the electronic device and can also change the operating parameters of the stressed device. The stress applied to the substrate may change the x-and/or y-dimensions of the substrate on which the device is formed, which in turn may change the operating parameters of the device. Circuitry for monitoring and helping to compensate for such mechanical stresses tends to increase the complexity of the circuit and/or require complex mathematical calculations during post-processing of the resulting measurements. Disclosure of Invention In described examples, a circuit includes an analog front end arranged to generate an analog stress compensation signal in response to an analog signal to be compensated and a first axis stress sensing signal. The analog front end may include a first precision component (e.g., 220) disposed on the piezoelectric material and arranged to generate an analog signal to be compensated for effects of stress applied in the piezoelectric material, and a directional stress sensor disposed on the piezoelectric material and coupled to the first precision component. The directional stress sensor is arranged to generate a first axis sensing signal in response to a longitudinal resultant of stresses applied in the piezoelectric material. The compensation circuit is arranged to generate a compensation output signal in response to the compensation analog signal and the analog signal to be compensated. Drawings Fig. 1A is a top view of an example semiconductor wafer. Fig. 1B is an orthogonal view of an example cross section of the example semiconductor wafer of fig. 1A. Fig. 1C is an orthogonal view of an example cross section of the example semiconductor wafer of fig. 1B. FIG. 2 is a top view of an example wafer including an example first axis stress sensor. FIG. 3 is an example graph showing the response of an example circuit to independently applied X-dimensional normal stress and Y-dimensional normal stress. FIG. 4 is a schematic diagram of an example Wheatstone bridge based analog front end for stress compensation of an analog signal. FIG. 5 is a schematic diagram of an example Wheatstone bridge based analog front end for feedback based stress compensation of an analog signal. FIG. 6 is a schematic diagram of an example op amp controlled current source for stress compensation of an analog signal. FIG. 7 is a schematic diagram of an example operational amplifier controlled amplifier for stress compensation of analog signals. FIG. 8 is a schematic diagram of an example current controlled current source for stress compensation of an analog signal. FIG. 9 is a schematic diagram of an example stress compensated bandgap reference circuit coupled to at least one of the example current controlled current sources of FIG. 8. Fig. 10 is a top view of a wafer 1000, the wafer 1000 being an example wafer including precision devices arranged between mutually sympathogenic direction stress sensors. Fig. 11 is a top view of a wafer 1100, the wafer 1100 being an example wafer including precision devices arranged between mutual longitudinal sense direction stress sensors. Fig. 12 is a top view of a wafer 1200. The wafer 1200 is an example wafer including an example structure of reference resistors and stress sense resistors of a wheatstone bridge. FIG. 13 illustrates an example region of a semiconductor substrate including an example precision component, an example first axis stress sensor, and an example second axis stress sensor. FIG. 14 is a layout diagram illustrating an example Wheatstone bridge configuration including two example X-axis sensors, each sensor having a respective example precision component. Fig. 15 is a layout diagram illustrating an example stress gradient of an example integrated circuit formed on a semiconductor substrate. Detailed Description In the drawings, like reference numerals designate like elements, and various features are not necessarily drawn to scale. The continual advances in semiconductor manufacturing have increased the integration, functionality, and speed of operation of electronic devices. The electronic device includes electronic devices/electrical components (such as resistors and transistors) that may be formed on a semiconductor substrate. At least some advances in semiconductor fabrication include the use of photolithography processes to form smaller and smaller structures so that less space on a semiconductor substrate can be used to form the structure of an electronic device. As such structures become smaller, the electrical properties of the formed components may be more affected by the given mechanical stresses encountered by the semiconductor substrate. In some examples, the applied mechanical stress affects various parameters of at least some semiconductor components according to a direction in which the mechanical stress i