Semiconductor integrated device for acoustic applications with contamination protection element, and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-9769554-B2
Application number	US-201514943848-A
Country	US
Kind code	B2
Filing date	Nov 17, 2015
Priority date	Mar 5, 2015
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A semiconductor integrated device, comprising: a package defining an internal space and having an acoustic-access opening in acoustic communication with an environment external to the package; a MEMS acoustic transducer, housed in the internal space and provided with an acoustic chamber facing the acoustic-access opening; and a filtering module, which is designed to inhibit passage of contaminating particles having dimensions larger than a filtering dimension and is set between the MEMS acoustic transducer and the acoustic-access opening. The filtering module defines at least one direct acoustic path between the acoustic-access opening and the acoustic chamber.

First claim

The invention claimed is:

1. A semiconductor package, comprising:
a package body having a base element and a covering element jointly defining an internal space of the package body and outer surfaces of the semiconductor package, said base element having an acoustic-access opening in acoustic communication with an environment external to the package body;
a MEMS acoustic transducer housed in the internal space of said package body and including an acoustic chamber facing the acoustic-access opening; and
a filtering module coupled to the package body and covering the acoustic-access opening, the filtering module being configured to inhibit passage of contaminating particles having dimensions larger than a filtering dimension, the filtering module being located between the MEMS acoustic transducer and the acoustic-access opening, said filtering module forming at least one direct acoustic path between the acoustic-access opening and the acoustic chamber.

2. The semiconductor package according to claim 1 , wherein said filtering dimension is between 10 μm and 35 μm.

3. The semiconductor package according to claim 1 , wherein said filtering module includes a filtering fabric having a plurality of threads interwoven according to a pattern that defines through openings of maximum dimension equal to said filtering dimension.

4. The semiconductor package according to claim 1 , wherein the base element includes a first substrate having said acoustic-access opening that extends through an entire thickness of the first substrate, and a second substrate having a hole that extends through an entire thickness of the second substrate, said filtering fabric being integrated in the base element between the first and second substrates,
wherein the first substrate, the second substrate, and the filtering fabric are coupled together in such a way that the acoustic-access opening and the hole are in direct acoustic connection with one another by the through openings of the filtering fabric.

5. The semiconductor package according to claim 3 , wherein the filtering module includes a first supporting plate and a second supporting plate provided with respective first and second windows, said filtering fabric being located between the first and second supporting plates in such a way that the first and second windows expose the same through openings of the filtering fabric,
and wherein the filtering module is housed in the internal space of the package so that the through openings directly face the acoustic chamber and the acoustic-access opening, thereby defining a direct acoustic path for an acoustic wave that propagates from the acoustic-access opening to the acoustic chamber through the second window, the first window, and the through openings.

6. The semiconductor package according to claim 1 , wherein said filtering module is a membrane of semiconductor material having a plurality of through openings,
said filtering module being completely housed in the internal space of the package so that the through openings directly face the acoustic chamber and the acoustic-access opening, thereby defining a direct acoustic path for an acoustic wave that propagates from the acoustic-access opening to the acoustic chamber through said through openings.

7. The semiconductor package according to claim 6 , wherein said through openings have a serpentine profile.

8. The semiconductor package according to claim 1 , wherein:
the MEMS acoustic transducer includes a structural layer having a front surface and a membrane at the front surface of the structural layer that flexes in response to sound waves, the structural layer having a rear portion, said acoustic chamber extending through said rear portion to said membrane; and
the rear portion of said structural layer is coupled to said filtering module and, the filtering module is coupled to an inner wall of said base element surrounding said acoustic-access opening.

9. The semiconductor package according to claim 1 , wherein said package further includes, in the internal space, a second die integrating a first ASIC electronic circuit functionally coupled to the MEMS acoustic transducer to receive and process a signal generated by the MEMS acoustic transducer as a function of an acoustic-pressure wave received by the MEMS acoustic transducer through said direct acoustic path.

10. The semiconductor package according to claim 1 , wherein said filtering module, along said direct acoustic path, is hydrophobic.

11. An electronic device, comprising:
a microprocessor; and
a semiconductor package coupled to the microprocessor, the semiconductor package including:
a package body defining an outer surface of the semiconductor package and an internal space, the package body having an acoustic-access opening in acoustic communication with an environment external to the package body;
a MEMS acoustic transducer housed in the internal space of the package body and having an acoustic chamber facing the acoustic-access opening of the package body; and
a filtering module coupled to the package body and located between the MEMS acoustic transducer and at least a portion of the acoustic-access opening, the filtering module configured to inhibit passage of contaminating particles having dimensions larger than a filtering dimension, the filtering module forming an acoustic path between the acoustic-access opening and the acoustic chamber.

12. The electronic device according to claim 11 , wherein the electronic device is at least one of a cellphone, a PDA, a notebook, a voice recorder, an audio-file reader with voice-recorder function, a console for videogames, a hydrophone, and a wearable device.

13. The electronic device according to claim 11 , wherein the filtering module includes a filtering fabric having a plurality of threads interwoven according to a pattern that defines through openings of maximum dimension equal to said filtering dimension.

14. The electronic device according to claim 11 , wherein said filtering module is a membrane of semiconductor material having a plurality of through openings.

15. A method for assembling a semiconductor package, the method comprising:
housing a MEMS acoustic transducer that includes an acoustic chamber in an internal space of a package body in such a way that the acoustic chamber faces an acoustic-access opening of the package body; and
arranging a filtering module configured to inhibit passage of contaminating particles having dimensions larger than a filtering dimension between the MEMS acoustic transducer and at least a portion of the acoustic-access opening to form a direct acoustic path between the acoustic-access opening and the acoustic chamber through the filtering module,
wherein the arranging comprises housing, between the MEMS acoustic transducer and the acoustic-access opening, a filtering fabric having a plurality of threads interwoven according to a pattern that defines through openings of a maximum dimension equal to said filtering dimension.

16. The method according to claim 15 , wherein the base element comprises a first substrate having said acoustic-access opening that extends throughout the thickness of the first substrate, and a second substrate having a hole that extends throughout the thickness of the second substrate,
wherein the step of arranging the filtering module comprising the steps of:
integrating said filtering fabric between the first and second substrates; and
coupling together the first substrate, the second substrate, and the filtering fabric in such a way that the acoustic-access opening and the hole are in direct aco

Assignees

• St Microelectronics Srl
• Stmicroelectronics (Malta) Ltd

Inventors

• Brioschi Roberto
• Adorno Silvia
• Fonk Kenneth

Classifications

• B81B2201/0257

  Microphones or microspeakers · CPC title

• H10W90/754

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/753

  between laterally-adjacent chips · CPC title

• H04R1/086 Primary

  Protective screens, e.g. all weather or wind screens · CPC title

• H04R31/00

  Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor {(manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182)} · CPC title