JP2010050537A - Crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size and height of a package of a crystal oscillator. <P>SOLUTION: The crystal oscillator 1 includes: a container body 2 having a step 2d at one side part of an inner wall and a recessed cross sectional shape; an IC chip 3 fixed to an inner bottom surface 2e of the container body 2 by flip-chip connection; and a crystal oscillator 4, one end of which is fixed to the step 2d and which is mounted in contact with the top surface of the IC chip 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crystal oscillator, for example, a surface-mount crystal oscillator, in which crystal resonators are horizontally arranged on the upper surface of a step portion of a ceramic package and one end thereof is fixed, and a crystal resonator is mounted on the upper surface of an IC chip. It relates to an oscillator.

  Crystal oscillators, particularly surface-mount crystal oscillators, are small and lightweight, and are therefore widely used especially for mobile communication devices such as mobile phones.

  In recent years, with the miniaturization of various electronic devices in which these crystal oscillators are built in, there is a strong demand for further miniaturization of the crystal oscillator itself, particularly reduction in thickness and height.

  As shown in FIG. 4, the conventional surface-mounted crystal oscillator 10 includes a laminated ceramic package 12 made of, for example, three ceramic substrates 12 a, 12 b, and 12 c, and the ceramic package 12. The IC chip 13 is fixed by flip chip connection with the circuit functional surface provided with the IC terminal on the inner bottom surface 12e thereof, and the stepped portion 12d of the ceramic package 12 is cantilevered by the electrode 16a and the conductive adhesive 15. The crystal resonator 14 is fixed at one end so as to form a gap g between the upper surface of the IC chip 13 and the lower surface of the crystal resonator 14.

  Here, the electrode 16 a is electrically connected to the extraction electrode 16 b provided on the main surface base portion of the crystal resonator 14 through the conductive adhesive 15. In addition, a predetermined number (for example, four) of mounting terminals 18 are provided on the bottom surface of the ceramic package 12, and the upper surface opening of the ceramic package 12 containing the crystal resonator 14 and the IC chip 13 has a metal cover. 17 is hermetically sealed.

  However, in such a conventional surface-mount crystal oscillator, when the crystal oscillator is miniaturized, the stepped portion 12d formed inside the ceramic package requires a considerable surface dimension. There is a possibility that the crystal resonator and the IC chip cannot be stored in the internal space of the package.

  That is, in the conventional downsized surface-mounted crystal oscillator 10, as described above, the IC chip 13 is mounted on the bottom surface 12e inside the ceramic package 12, and the electrode surface 16a formed on the step portion 12d inside the ceramic package 12 is used. A conductive adhesive 15 is applied to the upper surface of the applied adhesive 15, and the crystal resonator 14 is stepped so that the lead electrode 16 b formed on the main surface base of the crystal resonator 14 is electrically connected to the upper surface of the applied adhesive 15. Fixed to 12d and mounted in a cantilever shape.

  In order to securely fix the crystal resonator 14 to the stepped portion 12d, it is necessary to increase the area of the stepped portion 12d. For this purpose, the dimension of the inner wall surface of the ceramic package 12 is increased, or conversely, the IC chip 13 In addition, it is necessary to reduce the size of the crystal unit 14. However, it is technically very difficult to further reduce the dimensions of the IC chip 13 and the crystal resonator 14.

  If a ceramic package having an H-shaped cross section is used to form a two-chamber structure, for example, a crystal resonator is accommodated in the upper chamber and an IC chip is accommodated in the lower chamber, the IC chip. However, there is a problem that the crystal oscillator manufacturing process is complicated and long, and it is difficult to reduce the height of the crystal unit.

Furthermore, in the manufacturing process of the conventional crystal oscillator, as described above, after applying the conductive adhesive to the stepped portion of the ceramic package and then mounting the crystal resonator on the step, the application position of the adhesive is The problem is that the adhesive application state cannot be inspected after bonding because the crystal oscillator is mounted on the adhesive because the crystal electrode is mounted on the adhesive. There was a point.
JP 2008-42876 A

  The problem to be solved by the present invention is to reduce the size of the stepped portion inside the ceramic package as much as possible, and to reduce the size of the ceramic package of the crystal oscillator without changing the dimensions of the IC chip and the crystal unit. is there.

  In order to solve the above-described problems, the present invention provides a container main body having a stepped portion on one side of an inner wall and having a concave cross section, an IC chip fixed to the inner bottom surface of the container main body, and the stepped portion. And a crystal resonator mounted in contact with the upper surface of the IC chip.

  Miniaturization and low profile of the crystal oscillator package are achieved.

  Hereinafter, the crystal oscillator of the present invention will be described with reference to examples of the surface mount crystal oscillator.

  FIG. 1 is a longitudinal sectional view of a surface-mount type crystal oscillator according to an embodiment of the present invention, and FIG. 2 is a plan view of the surface-mounted crystal oscillator viewed without a cover.

  As shown in FIGS. 1 (a) and 2, a surface-mounted crystal oscillator 1 that is an embodiment of the crystal oscillator of the present invention is composed of, for example, three ceramic substrates 2a, 2b, and 2c stacked on the top surface. A ceramic package (container body) 2 having a concave cross section composed of an opening 2f, a bottom surface 2e formed on the lowermost ceramic substrate 2c, and a step 2d formed by the second ceramic substrate 2b, and the ceramic The IC chip 3 fixed by flip chip connection with the circuit functional surface provided with the IC terminal on the inner bottom surface 12e of the package 2 facing downward, and the electrode 6a (on the upper surface of the ceramic substrate 2b on the step portion 2d of the ceramic package 2) For example, it is formed by an Au or Ni plating pattern) and the conductive adhesive 5 or Au wire bonding 5a (see FIG. 1 (b)). It is deposited, also consisting of the other end is mounted in contact with the upper surface of the IC Chibbu 3 crystal oscillator 4.

  Here, the electrode 6a is electrically connected to the lead electrode 6b provided on the main surface base of the crystal unit 4 through the conductive adhesive 5 or the Au wire bonding 5a. In addition, a predetermined number, for example, four mounting terminals 8 are provided on the bottom surface of the ceramic package 12, and an upper surface opening 2 f of the ceramic package 2 containing the crystal resonator 4 and the IC chip 3 is formed of a metal. It is sealed and sealed with a cover 7 made of metal.

  In particular, in the surface-mount type crystal oscillator 1 according to the embodiment of the present invention, the stepped portion 2d and the IC chip 3 are arranged in a horizontal arrangement so that the positions in the height direction of the IC chip 3 are the same. The surface dimension of the stepped portion 2d formed inside can be reduced as much as possible, and the lower surface of the crystal unit 4 is mounted in contact with the upper surface of the IC chip 3 mounted on the bottom surface 2e inside the ceramic package 2. To do.

  At this time, the step in the height direction between the upper surface of the stepped portion 2d formed inside the ceramic package 2 and the upper surface of the crystal resonator 4 mounted via the conductive adhesive 5 or the Au wire bonding 5a is 0. Within 0.0 (equal) to 0.2 mm.

  Thereby, the mounting space for the ceramic package 2 is increased, and the ceramic package 2 can be miniaturized while keeping the dimensions of the IC chip 3 and the crystal resonator 4 as they are. Further, it becomes possible to mount the IC chip 3 and the crystal unit 4 having a size that is slightly larger while keeping the size of the ceramic package 2 as it is.

  Further, the electrode 6a formed on the upper surface of the stepped portion 2d and the extraction electrode 6b formed on the main surface of the upper surface of the crystal unit 4 are arranged substantially horizontally, and an adhesive is applied from the upper surface of the crystal unit 4. Both electrodes 6a and 6b are electrically connected by conductive adhesive 5 or Au wire bonding 5a. For this reason, the connection position with respect to the electrode 6b formed in the crystal unit 4 is stabilized, and the state of the connection portion can be inspected.

  By configuring the crystal oscillator of the present invention in this way, for example, the surface dimensions of the ceramic package 2 are changed to 1.0 mm × 1.0 mm to 5.0 mm × 3.2 mm, and the surface dimensions of the IC chip 3 are increased. 0.2 mm × 0.2 mm to 4.0 mm × 2. In addition, the surface dimension of the crystal unit 4 is 0.2 mm × 0.2 mm to 4.0 mm × 2.2 mm, and the surface dimension of the step portion 2 d formed on one inner wall of the ceramic package 2 is 0.1 mm. Each dimension can be reduced to 2 mm × 0.01 mm to 2.0 × 3.0 mm as compared with a conventional crystal oscillator.

  It can be used for crystal oscillators that require ceramic packages to be made smaller and lower in profile.

FIG. 1A is a longitudinal sectional view of an embodiment of the crystal oscillator of the present invention. FIG. 1A shows an example in which a conductive adhesive is used for fixing a crystal resonator, and FIG. An example using wire bonding is shown, and an example in which the dimensions of an IC chip and a crystal resonator are enlarged is shown. It is a top view of the crystal oscillator of this invention shown in FIG. It is a longitudinal cross-sectional view of the other Example of the crystal oscillator of this invention, Comprising: The example which reduced the ceramic package is shown. It is a longitudinal cross-sectional view of the conventional crystal oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crystal oscillator 2 Ceramic package 2a, 2b, 2c Ceramic substrate 2d Step part 3 IC chip 4 Crystal oscillator 5 Conductive adhesive 5a Au wire bonding 6a, 6b Electrode 7 Cover

Claims (6)

  A container main body having a stepped portion on one side of the inner wall and having a concave cross section, an IC chip fixed to the inner bottom surface of the container main body, and one end portion fixed to the stepped portion and the IC chip A crystal oscillator comprising: a crystal resonator mounted in contact with an upper surface.   2. The crystal oscillator according to claim 1, wherein the crystal resonators are arranged horizontally such that the upper surface of the stepped portion and the upper surface of the IC chip are in the same height direction.   The crystal oscillator according to claim 1, wherein an electrode formed on an upper surface of the step portion and an electrode formed on a main surface of the crystal resonator are connected by a conductive adhesive.   2. The crystal oscillator according to claim 1, wherein an electrode formed on an upper surface of the step portion and an electrode formed on a main surface of the crystal resonator are connected by Au wire bonding.   2. The electrode formed on the upper surface of the stepped portion and the electrode formed on the main surface of the crystal resonator are fixed to each other by an adhesive applied from the upper surface of the crystal resonator. The crystal oscillator described.   The crystal oscillator according to claim 1, wherein the crystal oscillator is a surface-mount crystal oscillator.

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