# US 10,118,820 B2 · Membrane transducer structures and methods of manufacturing same using thin-film encapsulation

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- Number: US 10,118,820 B2
- Document ID: US10118820B2
- Status: Granted
- Kind: B2
- Application number: 15/469,393
- Filed: 2017-03-24
- Published: 2017-07-13
- Granted: 2018-11-06
- Earliest claimed: 2014-07-25
- Assignees: Semiconductor Manufacturing International (Shanghai) Corporation
- Applicants: Semiconductor Manufacturing International (Shanghai) Corporation
- Inventors: Emmanuel P. Quevy; Jeremy R. Hui; Carrie Wing-Zin Low
- Web page: https://patentgrep.com/patent/US10118820B2

## CPC

- B81C 1/00246: {Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate}
- B81B 3/0021: {Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00)}
- B81B 7/007: {Interconnections between the MEMS and external electrical signals}
- B81B 7/0077: {Other packages not provided for in groups B81B7/0035 - B81B7/0074}
- B81B 7/008: {MEMS characterised by an electronic circuit specially adapted for controlling or driving the same (B81B7/0087 takes precedence; arrangements for starting, regulating, braking, or otherwise controlling an actuator H02N; control arrangements or circuits for visual indicators G09G3/00)}
- B81C 1/00158: {Diaphragms, membranes (manufacture process for semi-permeable inorganic membranes B01D67/0039)}
- B81C 1/00269: {Bonding of solid lids or wafers to the substrate}
- B81C 1/00285: {using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters}
- B81C 1/00333: {Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325}
- B81C 1/0038: {Processes for creating layers of materials not provided for in groups B81C1/00357 - B81C1/00373}
- G01N 27/223: {for determining moisture content, e.g. humidity (rain detectors on vehicle windows B60S1/0825)}
- G01N 27/227: {Sensors changing capacitance upon adsorption or absorption of fluid components, e.g. electrolyte-insulator-semiconductor sensors, MOS capacitors (G01N27/225 takes precedence)}
- B81B 2201/0214: Biosensors; Chemical sensors
- B81B 2201/0235: Accelerometers
- B81B 2201/0264: Pressure sensors
- B81B 2203/0127: Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
- B81B 2203/0315: Cavities
- B81C 2201/0105: Sacrificial layer
- B81C 2201/056: Releasing structures at the end of the manufacturing process
- B81C 2203/0118: Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
- B81C 2203/0136: Growing or depositing of a covering layer
- B81C 2203/0172: Seals
- B81C 2203/019: characterised by the material or arrangement of seals between parts
- B81C 2203/0735: Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Membrane transducer structures and thin-film encapsulation methods for manufacturing the same are provided. In one example, the thin film encapsulation methods may be implemented to co-integrate processes for thin-film encapsulation and formation of microelectronic devices and microelectromechanical systems (MEMS) that include the membrane transducers.

## Claims

### Claim 1

A method of forming a microshell membrane transducer structure, comprising:
providing a MEMS region over a substrate, the MEMS region including a MEMS structural layer defining at least one lower transducer capacitor plate over a MEMS sacrificial release layer;
forming a first sacrificial layer over the lower transducer capacitor plate;
forming a second sacrificial layer over and in contact with the first sacrificial layer, and then removing a part of the second sacrificial layer over at least a portion of the lower transducer capacitor plate so as to leave only the first sacrificial layer disposed over the portion of the lower transducer capacitor plate with no second sacrificial layer disposed over the portion of the lower transducer capacitor plate;
forming an upper microshell layer over the first sacrificial layer and lower transducer capacitor plate;
creating one or more upper release holes in the upper microshell layer; and
removing the first sacrificial layer disposed over the portion of the lower transducer capacitor plate through the upper release holes to form an open area between the upper microshell layer and the lower transducer capacitor plate such that a portion of the upper microshell layer forms a transducer membrane disposed over the open area and underlying lower transducer capacitor plate.

### Claim 2 (depends on 1)

The method of claim 1, further comprising removing the MEMS sacrificial release layer beneath the lower transducer capacitor plate through the upper release holes to release the lower transducer capacitor plate following the step of removing the first sacrificial layer disposed over the portion of the lower transducer capacitor plate through the upper release holes.

### Claim 3 (depends on 1)

The method of claim 1, further comprising forming a sealing layer on the upper microshell layer to seal the upper release holes in the upper microshell layer following the step of removing the first sacrificial layer disposed over the portion of the lower transducer capacitor plate through the upper release holes.

### Claim 4 (depends on 3)

The method of claim 3, further comprising removing a portion of the sealing layer to form a transducer opening above the transducer membrane that exposes an upper surface of the transducer membrane to an ambient environment.

### Claim 5 (depends on 1)

The method of claim 1, further comprising providing an integrated circuit (IC) region between the MEMS region and the underlying substrate, the IC region including integrated circuitry; forming multiple conductive vias extending between the MEMS structural layer and the integrated circuitry of the IC region; forming one or more lower transducer contacts that electrically couple the lower transducer capacitor plate to a first portion of the integrated circuitry of the IC region through one or more of the conductive vias; and forming one or more membrane transducer contacts that electrically couple the membrane transducer to a second portion of the integrated circuitry of the IC region through one or more of the conductive vias.

### Claim 6 (depends on 1)

The method of claim 1, where the flexible portion of the upper micro shell layer further comprises one or more out-of-plane decoupling structures disposed around an in-plane central portion of the flexible transducer membrane, an open area defined under each of the out-of-plane decoupling structures that is contiguous with a cavity or open area defined between the in-plane central portion of the flexible transducer membrane and the lower transducer capacitor plate.

### Claim 7 (depends on 6)

The method of claim 6, where the out-of-plane decoupling structures comprise upwardly extending hinge structures.

### Claim 8 (depends on 1)

The method of claim 1, where the flexible portion of the upper microshell layer is configured to flex closer and further away from lower transducer capacitor plate due to external stimulus.

### Claim 9 (depends on 8)

The method of claim 8, where the external stimulus comprises varying pressure.

### Claim 10 (depends on 4)

The method of claim 4, further comprising forming the transducer opening in the sealing layer above the flexible transducer membrane in an aligned position over the flexible transducer membrane.