Crystal oscillator fabrication methods using dual-deposition of mounting cement and dual-curing techniques

• US 9,445,536 B1
• Filed: 12/30/2014
• Issued: 09/13/2016
• Est. Priority Date: 08/30/2013
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Gubser, Robert A., Ghai, Ajay Kumar, Patel, Viresh Piyush
• Primary Examiner(s): LEE, DANIEL H.
• Application Number:
  US14/586,534
• Time in Patent Office: 623 Days
• Field of Search: 165/280
• US Class Current: 1/1
• CPC Class Codes: H03B 1/00 Details
• CPC Class Codes: H03H 2003/022 the resonators or networks being of the cantilever type
• CPC Class Codes: H03H 3/02 for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence
• CPC Class Codes: H03H 9/0547 consisting of a vertical arrangement H03H9/0566 takes precedence
• CPC Class Codes: H03H 9/1021 the BAW device being of the cantilever type
• CPC Class Codes: H03H 9/19 consisting of quartz

Abstract

A crystal oscillator fabrication method includes depositing mounting cement onto first and second mounting pads on a substrate to thereby define first and second electrode adhesion bumps. First and second electrodes of a crystal oscillator are electrically connected to the first and second mounting pads by contacting the first and second electrodes to the first and second electrode adhesion bumps and then curing the adhesion bumps. Next, mounting cement is deposited onto the first electrode and onto a portion of the first electrode adhesion bump to thereby define a top electrode adhesion extension. The top electrode adhesion extension is then cured.

Claims

1. A crystal oscillator fabrication method, comprising:

depositing electrically conductive mounting cement onto first and second electrically conductive mounting pads on a substrate to thereby define first and second electrode adhesion bumps thereon;

electrically connecting first and second electrodes of a crystal oscillator to the first and second mounting pads, respectively, by contacting the first and second electrodes to the first and second electrode adhesion bumps, respectively;

then

curing the first and second electrode adhesion bumps;

then

depositing electrically conductive mounting cement onto the first electrode and onto a portion of the first electrode adhesion bump to thereby define a top electrode adhesion extension; and

then

curing the top electrode adhesion extension.

2. The method of claim 1, wherein the crystal oscillator comprises a crystal blank;

wherein the first electrode extends primarily on a top surface of the crystal blank and partially on a bottom surface of the crystal blank; and

wherein the second electrode extends on a bottom surface of the crystal blank.

3. The method of claim 1, wherein the crystal oscillator comprises a crystal blank;

wherein the first electrode extends primarily on a top surface of the crystal blank and partially on a bottom surface of the crystal blank; and

wherein the second electrode extends primarily on a bottom surface of the crystal blank and partially on the top surface of the crystal blank.

4. The method of claim 3, wherein said depositing electrically conductive mounting cement comprises depositing electrically conductive mounting cement onto the second electrode and onto a portion the second electrode adhesion bump to thereby define a bottom electrode adhesion extension on the top surface of the crystal blank;

and wherein said curing the top electrode adhesion extension comprises curing the bottom electrode adhesion extension.

5. The method of claim 4, wherein all sides of the crystal blank have flat surfaces that meet the top and bottom surfaces of the crystal blank at right angles.

6. The method of claim 4, wherein the top electrode adhesion extension and the first electrode adhesion bump operate collectively to mechanically secure and electrically short the top electrode to the first mounting pad;

and wherein the bottom electrode adhesion extension on the top surface of the crystal blank and the second electrode adhesion bump operate collectively to mechanically secure and electrically short the bottom electrode to the second mounting pad.

7. The method of claim 3, wherein a plurality of sides of the crystal blank have flat surfaces.

8. The method of claim 1, wherein the top electrode adhesion extension and the first electrode adhesion bump operate collectively to mechanically secure and electrically short the top electrode to the first mounting pad.

9. The method of claim 1, wherein said depositing electrically conductive mounting cement onto the first electrode and onto a portion the first electrode adhesion bump comprises depositing the electrically conductive mounting cement directly onto the first mounting pad.

10. The method of claim 1, wherein the first mounting pad is a dumbbell-shaped mounting pad with a constricted neck region intermediate first and second opposing ends thereof;

and wherein the first electrode adhesion bump extends directly on the first end of the dumbbell-shaped mounting pad and the top electrode adhesion extension extends directly on the second end of the dumbbell-shaped mounting pad.

11. The method of claim 1, wherein the first electrode adhesion bump extends directly on a first portion of first mounting pad and the top electrode adhesion extension extends directly on a second portion of the first mounting pad.

12. A crystal oscillator fabrication method, comprising:

depositing electrically conductive mounting cement onto a first portion of an electrically conductive mounting pad to thereby define an electrode adhesion bump thereon;

electrically connecting an electrode of a crystal oscillator to the mounting pad by contacting the electrode to the electrode adhesion bump;

then

at least partially curing the electrode adhesion bump to mechanically secure the electrode to the mounting pad;

then

depositing electrically conductive mounting cement onto the electrode, at least a portion of the at least partially cured electrode adhesion bump and a second portion of the mounting pad to thereby define an electrode adhesion extension; and

then

curing the electrode adhesion extension to further mechanically secure and electrically short the electrode adhesion extension to the mounting pad.

13. The method of claim 12, wherein the crystal oscillator comprises a crystal blank having a plurality of sides with flat surfaces;

wherein the electrode contacts top and bottom surfaces of the crystal blank;

wherein said electrically connecting comprises electrically connecting a first portion of the electrode that contacts the bottom surface of the crystal blank to the mounting pad by contacting the first portion of the electrode to the electrode adhesion bump; and

wherein said depositing electrically conductive mounting cement onto the electrode comprises depositing electrically conductive mounting cement directly onto a second portion of the electrode that contacts the top surface of the crystal blank.

14. The method of claim 12, wherein the mounting pad is a dumbbell-shaped mounting pad with a constricted neck region intermediate first and second ends thereof, which correspond to the first and second portions of the mounting pad, respectively.