JP2013197694A - Surface mounted crystal oscillator and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator having one room structure which conducts measurement of electric characteristics of a crystal piece only by a crystal resonator thereby obtaining accurate results of the properties and achieves the height reduction.SOLUTION: An oscillator has one room structure where a crystal piece 2 and an IC chip 7 are housed in one recessed part 20 provided at a container 1. Electric characteristics of the crystal piece 2 are measured and then the IC chip 7 is mounted above the crystal piece 2. The one room structure is hermetically sealed by a metal cover 10 to form the low height oscillator.

Description

  The present invention relates to a single-chamber crystal oscillator in which a crystal resonator and an IC chip are mounted in the same space of a container, and relates to a low-profile surface-mount crystal oscillator capable of measuring its electrical characteristics and a manufacturing method thereof.

  Since the surface-mounted crystal oscillator is small and light, it is widely used as a frequency and time reference source particularly in small information terminals represented by mobile phones. One such surface-mounted crystal oscillator is a one-room structure in which a crystal resonator and an IC chip are housed in a container and hermetically sealed, and external terminals including crystal inspection terminals are provided on the outer surface of the container There are surface mount crystal oscillators.

  FIG. 11 is a side view for explaining the internal configuration by partially breaking a typical example of a conventional surface-mount crystal oscillator, and corresponds to the crystal oscillator described in Patent Document 1. This type of surface-mounted crystal oscillator described in Patent Document 1 (hereinafter sometimes simply referred to as an oscillator) accommodates an IC chip 7 and a crystal piece 2 in a container 1 and is preferably a metal plate. The cover 10 is joined and hermetically sealed. The container 1 is composed of a laminate of a bottom wall 1a, an intermediate frame wall 1b, and an upper frame wall 1c, and has a concave portion and a step portion at a central portion. The container 1 is formed by firing a ceramic sheet having a multilayer structure. The IC chip 7 is obtained by integrating elements such as an amplifier constituting an oscillation circuit. On the outer surface (back surface: mounting surface) of the bottom wall 1a of the container 1, mounting terminals 5a, 5b, 5c, and 5d including terminals that temporarily serve as crystal inspection terminals are provided.

  One main surface side of the IC chip 7 constituting the oscillation circuit together with the crystal resonator is fixedly mounted on the bottom surface of the concave portion of the container 1 by, for example, ultrasonic thermocompression using bumps 8. The input / output terminals (for example, power supply terminal, ground terminal, output terminal, AFC terminal, etc.) of the IC chip 7 are electrically connected to mounting terminals 5 formed at the four corners of the outer bottom surface of the container 1 through through holes or via holes. Has been. The mounting terminals 5b and 5c are temporarily connected to the crystal holding terminals 4 (two) connected to the extension portions of the two excitation electrodes formed on the crystal resonator. This connection is electrically connected to the printed wiring in the substrate (not shown) through the conductive paths 11a and 11b provided on the side surface of the container. In addition to the mounting terminals, there are some which are provided with terminals for inspecting crystal resonators and oscillation circuits. These terminals are collectively referred to as external terminals.

  In this crystal oscillator, the IC chip 7 is fixed to the bottom surface of the recess of the container 1, and then the crystal piece 2 is attached and sealed with the metal cover 10. The metal cover 10 is a metal plate such as Kovar, and is fixed to a metal film (metallized film) 9 formed on the open end of the upper frame wall 1c of the container 1 by fixing means such as seam welding. Thereafter, the probe of the inspection device is applied to the mounting terminals 5b and 5c of the crystal piece 2, and the electrical characteristics such as the oscillation frequency are measured. The measurement result (non-defective product / non-standard identification data) is stored in the storage means of the measuring device.

  After completing this measurement operation, the measurement is separated into individual oscillators. At this time, the oscillator determined to be out of specification by the measurement is excluded based on the data stored in the storage means, and the conductive paths 11a and 11b of the non-defective product are cut by means such as a laser. Note that the reproduction processing for those excluded as non-standard is not included in the scope of the present invention, and thus the description thereof is omitted.

JP 2010-103754 A JP 2004-112201 A

  In the one-room oscillator structure described above, an IC chip is first mounted in a recess formed in the central portion of the container, and then a crystal piece is mounted. The measurement of electrical characteristics of the crystal resonator with the IC chip connected to the crystal piece is slightly different from the measurement result of the crystal resonator alone. Since the size of the crystal piece is small, CI (crystal impedance: almost resistance value) is large, and the crystal piece is not sufficiently excited, so that required measurement may not be possible.

  In the invention described in Patent Document 2, a crystal piece is sealed in a recess formed toward the lower surface of the container to form a crystal resonator, and after checking the operation of the crystal resonator, the upper surface of the container (the side opposite to the recess) IC chip is mounted on the surface. However, in such a structure, the height size of the oscillator is large and it is difficult to reduce the height.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface-mounted crystal oscillator having a single-chamber structure capable of obtaining an accurate characteristic result by measuring the electrical characteristics of the crystal resonator only with the crystal resonator and reducing the height. And providing a manufacturing method thereof.

  In order to achieve the above object, according to the present invention, in an oscillator having a one-chamber structure in which a crystal piece and an IC chip are accommodated in a single recess provided in the container, only the crystal piece is placed on the bottom surface of the recess formed in the central portion of the container. The electrical characteristics of the vibrator were measured in the mounted state, and thereafter, an IC chip was mounted above the crystal piece and hermetically sealed with a metal cover to obtain a low-profile surface-mount crystal oscillator.

  Since the electrical characteristics can be measured in a state where the IC chip is not connected to the crystal oscillator, accurate results such as the oscillation frequency and the resistance value (CI) can be obtained. A low-profile surface-mounted oscillator can be provided by mounting a crystal piece and an IC chip in a recess having a one-room structure.

It is sectional drawing which shows the internal structure explaining Example 1 of the surface mount-type crystal oscillator based on this invention. It is sectional drawing explaining the container of the surface mount type crystal oscillator based on Example 1 of this invention. It is sectional drawing explaining the state which fixed the crystal oscillator to the container of the surface mount type crystal oscillator which concerns on Example 1 of this invention. It is the top view which looked at the container shown in FIG. 3 from the recessed part upper surface. It is a perspective view shown in the partial cross section explaining the state which fixed the crystal oscillator to the container of the surface mount type crystal oscillator which concerns on Example 1 of this invention. It is the top view which looked at the container of the crystal oscillator concerning Example 1 of the present invention from the back. It is sectional drawing explaining the measurement state of the electrical property of the crystal oscillator fixed to the container of the surface mount type crystal oscillator which concerns on Example 1 of this invention. It is sectional drawing which shows the state which mounted the IC chip in the container of the surface mount-type crystal oscillator which concerns on Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a surface-mounted crystal oscillator according to a first embodiment of the present invention, which is separately separated. It is the top view which looked at the container of the surface mount type crystal oscillator concerning Example 2 of the present invention from the back. FIG. 6 is a side view illustrating an internal configuration with a part of a typical example of a conventional surface-mount crystal oscillator partially broken.

  FIG. 1 is a cross-sectional view showing an internal structure for explaining a first embodiment of a surface-mount type crystal oscillator according to the present invention. A container 1 constituting the oscillator of FIG. 1 has a laminated structure of a bottom wall 1a, an intermediate frame wall 1b, and an upper frame wall 1c, and has a concave portion 20 and a step portion 21 in the central portion. The container 1 is formed by firing a ceramic sheet having a multilayer structure. The crystal piece 2 has excitation electrodes (not shown) on the front and back sides, and a pair of crystal holding terminals 4 (4a) provided on the inner bottom of the container 1 with connection portions extending from the excitation electrodes to one edge. , 4b) is fixed with conductive adhesive 3 (3a, 3b). In addition, this crystal oscillator is assembled in a state where a plurality of crystal oscillators are arranged in a matrix, hermetically sealed by a crystal piece, an IC chip, and a metal cover, and finally separated into individual crystal oscillators. Here, only one crystal oscillator is illustrated and described.

  In this crystal oscillator, an IC chip 7 is mounted with bumps 8a, 8b,... On a step portion 21 formed above the crystal piece 2 and on the inner periphery of the recess 20. The IC chip 7 is obtained by integrating elements such as an amplifier constituting an oscillation circuit together with the crystal piece 2. The outer surface of the bottom wall 1a of the container 1 is provided with mounting terminals 5 (5a, 5b, 5c, 5d) including terminals that temporarily serve as crystal inspection terminals.

  Each terminal (for example, power supply, ground, output, AFC terminal) of the IC chip 7 is electrically connected to mounting terminals 5 (5a, 5b, 5c, 5d) formed at the four corners of the outer bottom surface of the container 1. . The mounting terminals 5b and 5c are temporarily connected to the crystal holding terminals 4 (4a and 4b) connected to the extensions of the two excitation electrodes of the crystal resonator. In this embodiment, this connection is electrically connected in the same manner as the conventional example shown in FIG. 11 through a printed wiring in the substrate (not shown) and a conductive path (described later) provided on the side surface of the container.

  In this crystal oscillator, a probe of an inspection device is applied to mounting terminals 5b and 5c connected to a crystal holding terminal of the crystal piece 2 in a state where the crystal piece 2 is attached to the bottom surface of the concave portion of the container 1, and an electrical frequency such as an oscillation frequency is applied. Measure characteristics.

  Hereinafter, the structure of the crystal oscillator according to the present invention including the manufacturing process will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view for explaining the container of the crystal oscillator according to the present embodiment. In addition, FIG. 3, FIG. 7, FIG. 8 including FIG. 2 shows only a cut surface. The container 1 has a laminated structure of a bottom wall 1a, an intermediate frame wall 1b, and an upper frame wall 1c. The central portion has a recess 20 and a stepped portion 21. The container 1 is formed by firing a ceramic sheet having a multilayer structure. The container 1 has a plurality of external terminals on the outer surface of the bottom wall. The external terminal includes a mounting terminal and a crystal inspection terminal, but in FIG. 2 to FIG. 9, since the inspection terminal also serves as the mounting terminal, only the mounting terminal is provided. A required circuit / wiring pattern is formed on the boundary layer or the inner layer of the bottom wall 1a, the intermediate frame wall 1b, and the upper frame wall 1c.

  FIG. 3 is a cross-sectional view illustrating a state in which a crystal piece is fixed to the container of the crystal oscillator according to the present embodiment. FIG. 4 is a plan view of the container shown in FIG. FIG. 5 is a perspective view showing a partial cross section for explaining a state in which the crystal piece is fixed to the container of the crystal oscillator according to the present embodiment. FIG. 6 is a plan view of the crystal oscillator container according to the present embodiment as seen from the back. In addition, the external surface including the terminal for mounting in a mounting apparatus is provided in the outer surface of the bottom wall 1a. When the external terminal is only for mounting, it is called a mounting terminal.

  The crystal piece 2 is formed with excitation electrodes 2a and 2b on both front and back surfaces, and a part of each excitation electrode 2a and 2b extends to one end of the crystal piece, and this extended portion is formed on the inner bottom surface. It is fixed to the formed crystal holding terminals 4a and 4b with a conductive adhesive 3 (3a and 3b). As shown in FIG. 4, the crystal holding terminals 4a and 4b are connected to the mounting terminals 5 (5b and 5c) through the printed wiring patterns 12a and 12b on the bottom wall 1a and the conductive path connection patterns 11 (11a and 11b). The

  FIG. 7 is a cross-sectional view for explaining the measurement state of the electrical characteristics of the crystal resonator fixed to the container of the crystal oscillator according to the present embodiment. With the crystal piece 2 mounted on the container 1, the probe 6 (6a, 6b) of the measuring device is brought into contact with the mounting terminals 5b, 5c. Probes 6a and 6b are shown offset for easy understanding. A measurement signal is applied to the probe 6 (6a, 6b) to measure frequency characteristics, electrical characteristics such as impedance.

  FIG. 8 is a cross-sectional view showing a state in which the IC chip is mounted on the container of the crystal oscillator according to the present embodiment. The IC chip 7 is fixed with bumps 8 (8a, 8b, 8c,...) On a pad (not shown) connected to the wiring formed on the step portion 21 of the container by ultrasonic thermocompression bonding or the like. Thus, the IC chip 7 constitutes an oscillation circuit together with the crystal piece 2. Thereafter, as shown in FIG. 1 described above, the opening of the concave portion and the step portion of the container 1 is sealed with the metal cover 10. The metal cover 10 is a metal plate such as Kovar, and is fixed to a metal film (metallized film) 9 formed on the open end of the upper frame wall 1c of the container 1 by a fixing means such as seam welding, and a crystal piece and an IC chip are mounted. The space between the recessed portion and the stepped portion is sealed. Then, it is separated into individual crystal oscillators.

  FIG. 9 is a side view of the crystal oscillator according to the present embodiment separately separated. Of the separated crystal oscillators, the conductive paths 11 (11a, 11b) of the oscillators determined to be non-defective by the measurement are cut by means such as laser or gas ion irradiation. In FIG. 9, reference numeral 14 denotes a cut portion. By this cutting, the mounting terminals 5b and 5c lose their functions as inspection terminals.

  According to this embodiment configured as described above, the electrical characteristics can be measured in a state where the IC chip is not connected to the crystal oscillator, so that accurate results such as the oscillation frequency and the resistance value (CI) can be obtained. Can do. A low-profile oscillator can be provided by mounting a crystal piece and an IC chip in a recess having a one-room structure.

  FIG. 10 is a plan view of the container of the crystal oscillator according to the second embodiment of the present invention as seen from the back side. The second embodiment is different from the first embodiment in the configuration of the crystal inspection terminal. In the first embodiment described above, the crystal inspection terminal is also used as the mounting terminal. Therefore, the process of cutting the conductive path 11 (11a, 11b) after assembly is required.

  In the second embodiment, as shown in FIG. 10, crystal inspection terminals 15 (15a, 15b) independent of the mounting terminals 5 (5a, 5b, 5c, 5d) provided on the back surface of the crystal oscillator are provided. . The crystal piece 2 and the crystal inspection terminals 15 (15a, 15b) are electrically connected to the wiring pattern in the substrate of the container through through holes or via holes. In the crystal resonator inspection step, the crystal resonator is measured by bringing the probe of the inspection device into contact with the crystal inspection terminals 15 (15a, 15b).

  The crystal inspection terminal 15 (15a, 15b) is provided with a recessed portion 16 on the back surface (outer surface) of the container 1 in order to avoid a short circuit with a circuit or wiring pattern of the mounted device, and a terminal layer is embedded therein. It is preferable to provide a terminal layer so that the outer surfaces of the buried crystal inspection terminals 15a and 15b are set back from the outer surfaces of the mounting terminals 5 (5a, 5b, 5c and 5d). However, if it is not necessary to consider such a short, it may be flush with the mounting terminal.

  According to the second embodiment, in addition to the same effects as the first embodiment, the step of cutting the conductive paths 11 (11a, 11b) essential in the first embodiment is not required, and the manufacturing process can be simplified.

  In the second embodiment, the crystal inspection terminal is provided on the outer surface of the bottom wall, but the present invention is not limited to this and may be provided on the side surface of the crystal oscillator. In the third embodiment, the inspection terminal is provided on the side surface of the crystal oscillator, and the description by illustration is omitted.

  DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Crystal piece, 3 ... Conductive adhesive, 4 ... Crystal holding terminal, 5 ... Mounting terminal, 6 ... Probe, 7 ... IC chip, 8 ... bump, 9 ... metal film, 10 ... metal cover, 11 ... conductive path, 12 ... conductive path connection pattern, 14 ... cut portion, 15 ... crystal inspection terminal , 16 ... recessed part, 20 ... recessed part, 21 ... step part.

Claims (10)

A surface-mount crystal oscillator with a single-chamber structure consisting of a container with a crystal piece and an IC chip mounted in the center,
The container has a laminated structure of a bottom wall, an intermediate frame wall, and an upper frame wall, and has a recess and a step in a central portion surrounded by the intermediate frame wall and the upper frame wall,
The crystal piece is mounted with an excitation electrode fixed to a crystal holding terminal formed on the bottom surface of a recess formed in the central portion of the container,
The IC chip is mounted with a bump fixed to a pad of a wiring pattern formed on the stepped portion above the recess,
A metal cover which hermetically seals the concave portion and the stepped portion and is fixed to the upper frame wall;
A surface-mount type crystal oscillator comprising a plurality of surface-mounting terminals provided on an outer surface of the bottom wall. In claim 1,
A pair of a plurality of mounting terminals for surface mounting provided on the outer surface of the bottom wall is shared by the inspection terminals in the inspection of the crystal resonator,
A conductive path connection pattern is provided on the side surface of the container for electrically connecting the crystal holding terminal and a mounting terminal shared by the inspection terminal in the inspection of the crystal resonator, and cutting after the inspection. Surface mount crystal oscillator. In claim 1,
A surface-mount type crystal oscillator comprising a crystal inspection terminal connected to the crystal holding terminal via an in-substrate wiring of the container on an outer surface of the bottom wall. In claim 3,
A surface-mount type crystal having a recessed portion on an outer surface of the bottom wall of a portion where the crystal inspection terminal is provided, wherein the outer surface of the crystal inspection terminal is in a position retreated from the outer surface of the mounting terminal. Oscillator. A method of manufacturing a surface-mounted crystal oscillator having a one-room structure comprising a container having a crystal oscillator and an IC chip mounted in the center,
It has a laminated structure of a bottom wall, an intermediate frame wall, and an upper frame wall, has a plurality of external terminals on the outer surface of the bottom wall, and has a step portion and a recess surrounded by the intermediate frame wall and the upper frame wall. A mounting step of a crystal piece fixed to a crystal holding terminal formed on the inner bottom surface of the concave portion of the container;
A crystal resonator inspection process in which the probe of the inspection device is brought into contact with the external terminal and its electrical characteristics are measured,
After the inspection process, an IC chip mounting process for mounting bumps on the pads formed on the step surface and mounting an IC chip;
A sealing step in which a metal cover is fixed to the open end of the upper frame wall to hermetically seal the concave portion and the step portion of the container;
A method for manufacturing a surface-mount type crystal oscillator comprising: In claim 5,
The surface-mount type crystal oscillator characterized in that the external terminal with which the probe is contacted in the inspection of the crystal oscillator is also used as a part of a mounting terminal for mounting the crystal oscillator on a mounting device. Production method. In claim 6,
A method for manufacturing a surface-mounted crystal oscillator, comprising a cutting step of cutting a crystal holding terminal of the crystal resonator and an external terminal that is also used as the mounting terminal used for the inspection after the sealing step. In claim 5,
The external terminal that contacts the probe in the inspection of the crystal resonator is an inspection terminal provided on the outer surface of the bottom wall separately from a mounting terminal for mounting the crystal oscillator on a mounting device. A method for manufacturing a surface mount crystal oscillator. In claim 8,
An outer surface of the bottom wall on which the inspection terminal is provided has a recessed portion, and when the inspection terminal is formed in the recessed portion, the outer surface of the inspection terminal is retreated from the outer surface of the mounting terminal. A method for manufacturing a surface-mounted crystal oscillator. In claim 5,
A method for manufacturing a surface-mounted crystal oscillator, wherein an inspection terminal for contacting the probe in the inspection of the crystal resonator is provided on a side surface of the container instead of the outer surface of the bottom wall.

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