Packaging for piezoelectric resonator

• US 7,791,255 B2
• Filed: 11/13/2008
• Issued: 09/07/2010
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Micro Crystal AG (The Swatch Group AG)
• Original Assignee: ETA SA Manufacture Horlogã¨Re Suisse (The Swatch Group AG)
• Inventors: Dalla Piazza, Silvio, Hessler, Thierry
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US12/270,337
• Publication Number:
  US 20100117491A1
• Time in Patent Office: 663 Days
• Field of Search: 310/344, 310/348, 257/678, 257/724
• US Class Current: 310/348
• CPC Class Codes: B81B 2201/0271 Resonators; ultrasonic resonators
• CPC Class Codes: B81B 2207/096 through the substrate
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• CPC Class Codes: H03H 9/02818 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/02952 of parasitic capacitance
• CPC Class Codes: H03H 9/0557 the other elements being buried in the substrate
• CPC Class Codes: H03H 9/1021 the BAW device being of the cantilever type

Abstract

The invention concerns an assembly comprising a piezoelectric resonator (14) and a case (10), the case including a base part (11), on which the resonator is mounted, a wall (12) extending from said base part so as to surround at least partially said resonator, and a cover fixed to said wall in such a way as to close said case. The base part includes a main portion (17) and at least two conductive vias (16a, 16b). The conductive vias electrically connect The piezoelectric resonator to an outside circuit through the base part, and each of the conductive vias is surrounded by a insulating lining (18) so as to insulate the vias from the main portion (17). The main portion (17) of the base part (11) is divided into two parts by an insulating partition (21) in such a way that the two conductive vias are on different sides of the partition.

Claims

1. An assembly comprising a piezoelectric resonator and a case, said case including a base part, on which said resonator is mounted, a wall extending from said base part so as to surround at least partially said resonator, and a cover fixed to said wall in such a way as to close said case, the base part and the wall being made of silicon and being separated by a dielectric layer, wherein the base part includes a main portion and at least two conductive vias, the conductive vias electrically connecting said piezoelectric resonator to an outside circuit through the base part, and each of the conductive vias being surrounded by a insulating lining so as to insulate said vias from the main portion, wherein said main portion is divided into two parts by an insulating partition in such a way that the two conductive vias are on different sides of said partition.

2. The assembly according to claim 1, wherein said insulating partition is a trench filled with an insulating material.

3. The assembly according to claim 1, wherein the dielectric layer separating the base part from the wall, the insulating lining of the vias, and the insulating partition are all formed by dielectric oxide layers.

4. The assembly according to claim 1, wherein the silicon of which the base part is made is doped so as to render it electrically conducting, and wherein the conductive vias are made of the same doped silicon as the main portion.

5. The assembly according to claim 4, wherein the insulating lining of each of the vias is a peripheral trench etched through said doped silicon and filled with an insulating material.

6. The assembly according to claim 1, wherein the conductive vias are in the form of holes through the silicon base part, said holes being lined with an insulating dielectric and filled with electrically conducting material.

7. The assembly according to claim 6, wherein said electrically conducting material is metal.