PACKAGED DEVICE EXPOSED TO ENVIRONMENTAL AIR AND LIQUIDS AND MANUFACTURING METHOD THEREOF

• US 20140061892A1
• Filed: 08/29/2013
• Published: 03/06/2014
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Ziglioli, Federico Giovanni, Fontana, Fulvio Vittorio, Maggi, Luca
• Granted Patent: US 9,011,776 B2
• Time in Patent Office: Days
• US Class Current: 257/704
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 7/0058 for protecting against damages due to external chemical or mechanical influences, e.g. shocks or vibrations
• CPC Class Codes: B81B 7/0077 Other packages not provided for in groups B81B7/0035 - B81B7/0074
• CPC Class Codes: B81C 1/00333 Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48145 the bodies being stacked
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H04R 1/086 Protective screens, e.g. all weather or wind screens
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005

Abstract

A packaged device, wherein at least one sensitive portion of a chip is enclosed in a chamber formed by a package. The package has an air-permeable area having a plurality of holes and a liquid-repellent structure so as to enable passage of air between an external environment and the chamber and block the passage of liquids.

Claims

1. A packaged device, comprising:

a chip; and

a package body delimiting a chamber, at least a portion of the chip being located in the chamber, the package body including an air-permeable area having a plurality of holes and a liquid-repellent structure that together enable passage of air between an external environment and the chamber and block passage of liquids.

2. The packaged device according to claim 1, wherein the plurality of holes have a maximum width between 0.1 and 100 μ

m and have a pitch between 0.3 and 300 μ

m.

3. The packaged device according to claim 1, wherein the package includes a protective cap delimiting an upper portion the chamber and defines an outer surface.

4. The packaged device according to claim 3, wherein the liquid-repellent structure includes a rough nanostructure on the outer surface of the protective cap.

5. The packaged device according to claim 4, wherein the rough nanostructure has a roughness value between 1 and 3 μ

m and a maximum deviation between 2 and 20 μ

m.

6. The packaged device according to claim 3, wherein the outer surface of the protective cap has a plurality of microreliefs, the microreliefs having a regular structure and being uniformly arranged on the outer surface of the protective cap.

7. The packaged device according to claim 1, wherein the liquid-repellent structure includes a hydrophobic/lipophobic layer that covers the protective cap and is provided with openings overlying the holes.

8. The packaged device according to claim 7, wherein the hydrophobic/lipophobic layer includes at least one of Teflon, silicon carbide, resist, metal, polymer, C₄F₈ polymer having a static contact angle greater than 100°

, a spectral absorption peak at a wave number between 1200 cm<sup>−

1</sup> and 1300 cm<sup>−

1</sup>, organometal, and transition-metal complex.

9. The packaged device according to claim 3, wherein the protective cap includes at least one of silicon, metal, plastic, and ceramic.

10. The packaged device according to claim 1, wherein the chip integrates a MEMS, and an upper surface of the MEMS is located in the chamber.

11. A method for manufacturing a packaged device, the method comprising:

forming a package body delimiting a chamber;

enclosing at least a portion of a chip in the package body with the chamber being located over a sensitive portion of the chip;

forming an air-permeable area in the package body that includes forming a plurality of holes; and

forming a liquid-repellent structure on the package body at the air-permeable area.

12. The method according to claim 11, wherein forming the liquid-repellent structure comprises providing a rough structure having microreliefs on an outer surface of the air-permeable area.

13. The method according to claim 11, wherein forming the liquid-repellent structure comprises forming a hydrophobic/lipophobic layer on top of the outer surface of the air-permeable area.

14. The method according to claim 13, wherein forming the package body includes forming a protective cap over the sensitive portion of the cap.

15. The method according to claim 14, wherein forming the hydrophobic/lipophobic layer comprises dipping the protective cap in a solution or depositing via spinning material having hydrophobic/lipophobic characteristics.

16. The method according to claim 11, wherein forming the plurality of holes is carried out before or after forming the liquid-repellent structure.

17. A packaged device, comprising:

a chip that includes a membrane;

a package body having an inner chamber, a portion of the chip being located in the chamber of the package body, the package body including a structure having an inner surface located proximate the inner chamber and an outer surface, the structure including a plurality of holes that extend from the outer surface to the inner surface, the plurality of holes being configured to allow air to flow between an environment outside of the package body and the inner chamber, the outer surface of the structure having a roughened surface that is configured to prevent water droplets from being provided to the inner chamber.

18. The packaged device according to claim 17 wherein the structure is a cap of the package body and is located over the membrane of the chip.

19. The packaged device according claim 17 wherein the structure has roughness value between 0.5 and 3 μ

m.

20. The package device according claim 17 wherein the roughened surface includes a plurality of pillars, each having a similar shape as each other.

21. The packaged device according to claim 17 wherein a portion of the chip forms the package body.

22. The packaged device according to claim 17 wherein the chip includes at least one of a pressure sensor, a microphone and a gas sensor.