Method for inspecting physical quantity sensor and method for manufacturing physical quantity sensor

• US 10,041,796 B2
• Filed: 03/21/2016
• Issued: 08/07/2018
• Est. Priority Date: 04/01/2015
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Oshio, Masahiro, Sato, Kenji
• Primary Examiner(s): HULS, NATALIE F
• Application Number:
  US15/075,656
• Publication Number:
  US 20160290828A1
• Time in Patent Office: 869 Days
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/5726 Signal processing
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

A method for inspecting a physical quantity sensor includes: applying a test drive signal while changing a voltage level, to an angular velocity sensor as a physical quantity sensor having a detection portion which performs detection vibration according to a physical quantity; detecting an output signal from the detection portion corresponding to the test drive signal, as a test detection signal; and performing pass/fail determination based on a change in the test detection signal in relation to the change in the voltage level.

Claims

1. A method for inspecting a physical quantity sensor, the method comprising:

applying a test drive signal, while changing a voltage level, to a physical quantity detection element having a detection portion which performs detection vibration according to a physical quantity;

detecting a leakage signal from the detection portion corresponding to the test drive signal, as a test detection signal, the leakage signal being a signal generated in the detection portion when there is no Coriolis force applied to the detection portion; and

performing a pass/fail determination based on a change in the test detection signal in relation to the change in the voltage level.

2. The method for inspecting the physical quantity sensor according to claim 1, wherein the physical quantity detection element further includes a drive portion which performs drive vibration as the test drive signal is applied thereto, and

the leakage signal is generated on the basis of the drive vibration of the drive portion.

3. The method for inspecting the physical quantity sensor according to claim 2, wherein the pass/fail determination is performed on the basis of a rate of change in voltage of the test detection signal in relation to the voltage level when the voltage level is raised from a first level to a second level that is higher than the first level.

4. The method for inspecting the physical quantity sensor according to claim 2, wherein the voltage level is raised from a first level to a second level that is higher than the first level,

the voltage level is lowered from the second level to the first level, and

the pass/fail determination is performed on the basis of a difference between a voltage of the test detection signal when the voltage level rises from the first level and a voltage of the test detection signal when the voltage level has fallen to the first level.

5. The method for inspecting the physical quantity sensor according to claim 2, wherein the physical quantity sensor further includes a drive circuit which causes the drive portion to perform the drive vibration, and

the drive circuit generates the test drive signal on the basis of a variable external voltage inputted from outside.

6. The method for inspecting the physical quantity sensor according to claim 2, wherein the physical quantity sensor further includes a drive circuit which causes the drive portion to perform the drive vibration,

the drive circuit has a reference voltage circuit configured to generate n different kinds of reference voltages from a first reference voltage to an n-th reference voltage (n being an integer equal to or greater than 2), and

the voltage level of the test drive signal is based on the reference voltages.

7. The method for inspecting the physical quantity sensor according to claim 1, wherein the pass/fail determination is performed on the basis of a rate of change in voltage of the test detection signal in relation to the voltage level when the voltage level is raised from a first level to a second level that is higher than the first level.

8. The method for inspecting the physical quantity sensor according to claim 1, wherein the voltage level is raised from a first level to a second level that is higher than the first level,

the voltage level is lowered from the second level to the first level, and

the pass/fail determination is performed on the basis of a difference between a voltage of the test detection signal when the voltage level rises from the first level and a voltage of the test detection signal when the voltage level has fallen to the first level.

9. A method for manufacturing a physical quantity sensor, the method comprising:

preparing a package for accommodating a physical quantity detection element and an IC chip, the physical quantity detection element having a detection portion which performs detection vibration according to a physical quantity;

forming the IC chip from a semiconductor substrate;

mounting the physical quantity detection element above the IC chip and in electrical connection with the IC chip; and

an inspection process including;

applying a test drive signal, while changing a voltage level, to a physical quantity detection element;

detecting a leakage signal from the detection portion corresponding to the test drive signal, as a test detection signal, the leakage signal being a signal generated in the detection portion when there is no Coriolis force applied to the detection portion; and

performing a pass/fail determination based on a change in the test detection signal in relation to the change in the voltage level.

10. The method for manufacturing the physical quantity sensor according to claim 9, wherein the physical quantity detection element further includes a drive portion which performs drive vibration as the test drive signal is applied thereto, and

the leakage signal is generated on the basis of the drive vibration of the drive portion.

11. The method for manufacturing the physical quantity sensor according to claim 10, wherein the pass/fail determination is performed on the basis of a rate of change in voltage of the test detection signal in relation to the voltage level when the voltage level is raised from a first level to a second level that is higher than the first level.

12. The method for manufacturing the physical quantity sensor according to claim 10, wherein the voltage level is raised from a first level to a second level that is higher than the first level,

the voltage level is lowered from the second level to the first level, and

the pass/fail determination is performed on the basis of a difference between a voltage of the test detection signal when the voltage level rises from the first level and a voltage of the test detection signal when the voltage level has fallen to the first level.

13. The method for manufacturing the physical quantity sensor according to claim 10, wherein the physical quantity sensor further includes a drive circuit which causes the drive portion to perform the drive vibration, and

the drive circuit generates the test drive signal on the basis of a variable external voltage inputted from outside.

14. The method for manufacturing the physical quantity sensor according to claim 10, wherein the physical quantity sensor further includes a drive circuit which causes the drive portion to perform the drive vibration,

the drive circuit has a reference voltage circuit configured to generate n different kinds of reference voltages from a first reference voltage to an n-th reference voltage (n being an integer equal to or greater than 2), and

the voltage level of the test drive signal is based on the reference voltages.

15. The method for manufacturing the physical quantity sensor according to claim 9, wherein the pass/fail determination is performed on the basis of a rate of change in voltage of the test detection signal in relation to the voltage level when the voltage level is raised from a first level to a second level that is higher than the first level.

16. The method for manufacturing the physical quantity sensor according to claim 9, wherein the voltage level is raised from a first level to a second level that is higher than the first level,

the voltage level is lowered from the second level to the first level, and

the pass/fail determination is performed on the basis of a difference between a voltage of the test detection signal when the voltage level rises from the first level and a voltage of the test detection signal when the voltage level has fallen to the first level.