SELF-POWERED PIEZOELECTRIC ENERGY HARVESTING MICROSYSTEM

• US 20150008792A1
• Filed: 07/07/2014
• Published: 01/08/2015
• Est. Priority Date: 07/05/2013
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Gong, Cuiling, Wang, Jianbai Jenn
• Granted Patent: US 9,716,446 B2
• Time in Patent Office: Days
• US Class Current: 310/319
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/075 the electronic processing unit being integrated into an element of the micromechanical structure
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H02N 2/186 Vibration harvesters
• CPC Class Codes: H02N 2/22 Methods relating to manufacturing, e.g. assembling, calibration
• CPC Class Codes: H10N 30/30 with mechanical input and electrical output, e.g. functioning as generators or sensors
• CPC Class Codes: H10N 30/304 Beam type
• CPC Class Codes: H10N 30/306 Cantilevers
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A self-powered piezoelectric energy harvesting microsystem device has CMOS integrated circuit elements, contacts and interconnections formed at a proof mass portion of a die region of a semiconductor wafer. Piezoelectric energy harvesting unit components connected to the integrated circuit elements are formed at a thinned beam portion of the die region that connects the proof mass portion for vibration relative to a surrounding anchor frame portion. A battery provided on the proof mass portion connects to the integrated circuit elements. In a cantilever architectural example, the battery is advantageously located at a distal end of the proof mass portion, opposite the joinder with frame portion via the beam portion.

Claims

1. A method of forming a self-powered piezoelectric energy harvesting microsystem, comprising:

forming integrated circuit elements including transistor gate structures and source/drain regions using CMOS processing steps at a proof mass first portion of a die region of a semiconductor wafer substrate;

depositing and patterning dielectric layers and metal layers at the first portion of the die region to form contacts and interconnections for the integrated circuit elements;

depositing and patterning first electrode, piezoelectric material and second electrode layers at a beam second portion of the die region to form piezoelectric energy harvesting unit components connected to the integrated circuit elements;

etching fully through the substrate to form a support frame third portion of the die region separated by a gap from a majority of the first portion and joining by the second portion to a minority of the first portion;

etching partially through the substrate to thin the second portion; and

providing a battery connected to the integrated circuit elements at the first portion of the die region.

2. The method of claim 1, wherein the integrated circuit elements are formed at a first region of the first portion, and the battery is provided at a second region laterally spaced from the first region of the first portion.

3. The method of claim 2, wherein the third portion is separated by a gap along three sides of the first portion and joined by the second portion along a fourth side of the first portion.

4. The method of claim 3, wherein the battery is provided at an end of the first portion laterally distal from the fourth side of the first portion.

5. A self-powered piezoelectric energy harvesting microsystem device, comprising:

integrated circuit elements, including transistor gate structures and source/drain regions formed using CMOS processing steps, located at a proof mass portion of a die region of a semiconductor wafer substrate;

contacts and interconnections for the integrated circuit elements formed by dielectric layers and metal layers over the proof mass portion of the die region;

piezoelectric energy harvesting unit components connected to the integrated circuit elements formed by first electrode, piezoelectric material and second electrode layers at a beam portion of the die region; and

a battery provided on the proof mass portion connected to the integrated circuit elements;

wherein the die region includes a support frame portion separated by a gap from a majority of the proof mass portion;

the beam portion has a thickness less than the proof mass and support frame portions and joins a minority of the proof mass portion to the support frame portion.

6. The device of claim 5, wherein the integrated circuit elements are provided at a first region of the proof mass portion;

and the battery is provided at a second region of the proof mass portion laterally spaced from the first region.

7. The device of claim 6, wherein the device has a cantilever structural configuration with the proof mass portion separated by a gap from the support frame portion along three sides of the proof mass portion, and the beam portion joining the proof mass portion to the support frame portion along a fourth side of the proof mass.

8. The device of claim 7, wherein the battery is located adjacent a side of the proof mass portion which is opposite to the fourth side of the proof mass portion.

9. The device of claim 8, wherein the die region is a singulated die region defining a die.