JP2007093215A - Probe pin, monitor electrode pad, package for surface mounting, and piezoelectric oscillator for surface mounting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe pin, capable of frequency measurement by ensuring ample contact area and contacting the monitor electrode pad arranged in an insulation package for surface mounting. <P>SOLUTION: In the probe pin 40 for measuring the frequency by contacting the tip end with respect to a monitor electrode pad 30 for a piezoelectric vibration element conducting the piezoelectric vibration element, which is arranged on the inner surface of a cavity 3 for an IC component of the package, provided with a cavity 2 containing the piezoelectric vibration element 12 and the cavity 3 containing the IC component 20 constituting an oscillation circuit, a recess part dented in a concave is provided to the tip end of the probe pin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an improvement of a probe pin that comes into contact with a monitor electrode pad for frequency measurement provided in a surface-mount piezoelectric oscillator.
Furthermore, the present invention relates to an improvement of a monitor electrode pad for adjusting a frequency of a piezoelectric vibration element provided in a surface mount type piezoelectric oscillator, and more particularly, a pattern adapted to a shape of a tip surface of a probe pin for performing frequency measurement work. The present invention relates to a monitor electrode pad, a package for surface mounting, and a piezoelectric oscillator for surface mounting.

In the mobile communications market, an increasing number of manufacturers are promoting modularization of parts groups for each function, taking into account the mounting properties, maintenance and handling characteristics of various electrical components, and the commonality of parts between devices. . Further, along with modularization, there is a strong demand for downsizing and cost reduction.
In particular, there is an increasing tendency toward modularization of circuit components that have established functions and hardware configurations, such as a reference oscillation circuit, a PLL circuit, and a synthesizer circuit, and that require high stability and high performance. Furthermore, there is an advantage that a shield structure can be easily established by packaging these parts as a module.
Examples of surface mounting electronic components constructed by modularizing and packaging a plurality of related components include piezoelectric vibrators, piezoelectric oscillators, SAW devices, etc., but these functions are maintained at a high level. However, in order to achieve further miniaturization, for example, Patent Document 1 proposes a crystal oscillator having a two-story module structure. This crystal oscillator is one in which a crystal resonator element and other oscillation circuit elements are incorporated in one insulating package.
In this crystal oscillator, a crystal resonator element is accommodated in one of the cavities provided independently on the front and back surfaces of a ceramic circuit board (ceramic container) having an H-shaped longitudinal section, and the other cavity is accommodated. An IC chip (IC component) is accommodated as the oscillation circuit element, and the crystal vibration element and the IC chip are connected in conduction by circuit wiring provided in bonding or a package.

When assembling a crystal oscillator having such a configuration, an assembly process is performed in which a crystal resonator element is first mounted in one cavity to complete a crystal resonator, and then an IC chip is mounted in the other cavity.
Therefore, in order to check the function (frequency) of the completed crystal resonator, a monitor electrode pad for the crystal resonator element that is electrically connected to the excitation electrode of the crystal resonator element is provided on the outer surface of the insulating package, and the frequency is applied to the monitor electrode pad. It is necessary to configure so that the probe pin tip of the measuring device can be brought into contact. That is, in the frequency adjustment work, the frequency that is output by exciting the crystal resonator element by energizing the probe pin of the frequency measuring device in contact with the monitor electrode pad, and checking the target frequency and the actual frequency. If there is an error between the two, the adjustment is made by a method such as increasing or decreasing the thickness of the excitation electrode film on the crystal resonator element.
The position of the crystal vibration element monitor electrode pad can be provided on the side surface portion of the outer surface of the package, but in this case, there is a problem that it is easily affected by electromagnetic waves from the outside of the package. Therefore, in general, a monitor electrode for a crystal resonator element is provided at a position on the bottom surface in the cavity on the side where the IC chip is accommodated and covered with the IC chip. In this case, the step of mounting the IC chip in the cavity is performed after the frequency measurement using the monitor electrode pad is completed.
As a result, the monitor electrode pad for the crystal resonator element is shielded electromagnetically by the shielding metal lid for covering the crystal resonator element while concealing the monitor electrode pad for the crystal resonator element with the IC chip.

By the way, the structure of the monitor electrode pad for a crystal resonator element is usually rectangular, and the tip of a measurement terminal having a sharp tip such as a probe pin is brought into contact with the surface portion of the monitor electrode pad.
However, when the tip of the probe pin has a shape like a sharp needle, the portion where the probe pin comes into contact with the monitor electrode pad for the crystal resonator element is only a small point on the tip of the needle, and such a small tip It is not easy to properly abut the monitor electrode pad for a crystal resonator element with a small area, and there are many cases where it cannot be sufficiently contacted.
In addition, when the probe is a quadrangular prism and its tip is flat, the contact area of the probe seems to be wide at first glance, but the crystal vibrating element monitor electrode pad 101 provided on the surface of the package 100 as shown in FIG. Since the shape is a structure in which the central portion is thick and becomes thin according to the outer periphery, the probe pin 102 can contact only the central portion of the monitor electrode pad 101, and the contact area is small. For this reason, poor contact is likely to occur. The monitor electrode pad 101 is formed by applying a conductive material such as tungsten using a screen printing method. The monitor electrode pad 101 is rounded under the influence of surface tension in the fluid state immediately after application, and the pad electrode If is small, it will be closer to a sphere (hemisphere). For this reason, the contact area with the probe pin 102 having a flat tip surface is further narrowed, thereby increasing the impedance value due to the contact resistance between the pad electrode and the probe pin 102, so that the frequency can be measured correctly. It becomes even more difficult, and this is a big problem for crystal resonators or crystal oscillators that require particularly high frequency accuracy.
In the case of inputting / outputting signals other than the oscillation operation input / output signal, for example, a digital signal for IC adjustment, even if the contact resistance with the probe pin increases, the digital signal data is 0/1 information. It will not be.
Next, when the crystal oscillator is further downsized, the diameter of the gold bump for connecting and fixing the IC chip on the connection pad of the package is also reduced, thereby reducing the distance between the circuit surface of the IC chip and the monitor electrode pad. As a result, the parasitic capacitance generated between the two tends to increase. Since the parasitic capacitance causes an unstable operation for the oscillation operation of the crystal oscillator, problems such as an unstable operation of the crystal oscillator occur when the parasitic capacitance increases.
Japanese Patent No. 3398331

The present invention has been made in view of the above, and a probe pin capable of performing frequency measurement by making contact with a monitor electrode pad disposed in an insulating package for surface mounting while ensuring a sufficient contact area. One purpose is to provide
In addition, the present invention provides a monitor electrode pad that can ensure a sufficient contact area regardless of the shape of the tip surface of the probe pin, an insulating package including the same, and a surface mount piezoelectric oscillator. It is aimed.

In order to solve the above-mentioned problems, a probe pin according to the invention of claim 1 includes a recess for accommodating a piezoelectric vibration element and a recess for the IC component of a package including a recess for accommodating an IC component constituting an oscillation circuit. In a probe pin for measuring the frequency by bringing the tip portion into contact with the monitor electrode pad for the piezoelectric vibration element that is disposed on the inner surface and is electrically connected to the piezoelectric vibration element, the tip surface of the probe pin has a concave shape. It is characterized by providing a recessed portion which is depressed in the.
According to a second aspect of the present invention, there is provided a surface mounting package including a recess for accommodating a piezoelectric vibration element, a recess for accommodating an IC component constituting an oscillation circuit, and an inner surface of the recess for the IC component. In a surface-mount package comprising a monitor electrode pad for a piezoelectric vibration element that is electrically connected to the vibration element, the monitor electrode pad has a configuration in which a plurality of strip-shaped portions extend radially from a central portion. It is characterized by.
The invention of claim 3 is characterized in that, in claim 2, the monitor electrode pad has a cross-shaped configuration.
According to a fourth aspect of the present invention, in the second aspect, the monitor electrode pad has a Y-shaped configuration.
According to a fifth aspect of the present invention, there is provided a recess for accommodating a piezoelectric vibration element, a recess for accommodating an IC component constituting an oscillation circuit, and a piezoelectric element disposed on the inner surface of the recess for the IC component and electrically connected to the piezoelectric vibration element. In a surface mounting package including a monitor electrode pad for a vibration element, the monitor electrode pad is formed in an annular shape.
A sixth aspect of the invention is characterized in that the monitor electrode pad according to any one of the second to fifth aspects is provided.
The invention according to claim 7 is characterized in that the piezoelectric vibration element and the IC component are accommodated in the respective recesses of the package for surface mounting according to claim 6.

In the probe pin according to the present invention, since the concave portion is provided in the tip end surface of the probe pin, a sufficient contact area is ensured with respect to the monitor electrode pad disposed in the surface mount insulating package. The frequency measurement can be performed by contact.
The monitor electrode pad (adjustment terminal) according to the present invention can ensure a sufficient contact area regardless of the shape of the tip surface of the probe pin. Connection stability with the monitor electrode pad can be secured.
Further, by forming the monitor electrode pad in an annular shape, the area thereof is markedly narrower than that of the conventional rectangular adjustment terminal, so that the parasitic capacitance can be kept small.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIGS. 1A and 1B are surface mounts having a package structure having an adjustment terminal (monitor electrode pad) for performing frequency measurement by contacting the tip of a probe pin according to an embodiment of the present invention. It is the longitudinal cross-sectional view and bottom view of the crystal oscillator as an example of a type piezoelectric oscillator.
This crystal oscillator has recesses (cavities) 2 and 3 on the upper surface and the lower surface, respectively, and on the annular bottom surface 4 a drive power supply mounting terminal (Vcc terminal), a control voltage application mounting terminal (Vcon terminal), and a signal output An insulating container 1 having a vertical cross-sectional shape having four mounting terminals 5 including a mounting terminal (Out terminal) and a grounding mounting terminal (Gnd terminal), and two upper surface sides provided in the upper surface side recess 2 A metal lid 15 that hermetically seals the upper surface side recess 2 in a state where the two excitation electrodes on the crystal vibration element (piezoelectric vibration element) 12 are electrically connected to the internal pad 11, and the lower surface side recess 3. The upper surface side internal pads 11 disposed on the ceiling surface 3 a and the lower surface side internal pads 6 that are electrically connected to the mounting terminals 5, and the IC component 20 that constitutes an oscillation circuit mounted on the lower surface side internal pads 6 are provided. In this embodiment, the case where the Vcc terminal and the Vcon terminal of the four mounting terminals 5 are electrically connected to one of the upper surface side internal pads 11 will be described as an example.

The insulating container 1, the lower surface side internal pad 6, the upper surface side internal pad 11, and the metal lid 15 constitute a surface mount type piezoelectric oscillator package (package).
The upper portion of the insulating container 1 having the upper surface side recess (IC component recess) 2, the upper surface side internal pad 11, the crystal resonator element 12, and the metal lid 15 constitute a crystal resonator (piezoelectric resonator). is doing. That is, the crystal resonator is electrically connected to the crystal resonator element 12 on the upper surface side internal pad 11 in the upper surface side recess 3 of the insulating container 1 made of an insulating material such as ceramic by using a conductive adhesive (conductive paste) 13. The metal lid 15 is electrically and mechanically connected to the conductor ring on the upper surface of the outer wall of the insulating container 1 by welding or the like, and the inside of the upper side recess 2 is hermetically sealed.
In this package, the frequency characteristic of the crystal resonator element 12 is measured, and if there is an error between the measured actual frequency and the target frequency, an adjustment terminal (monitor electrode pad) used for adjusting the error is measured. ) 30 is arranged in the ceiling surface 3a of the lower surface side recess 3 and other appropriate positions.
The adjustment terminal 30 is used to output a frequency output by exciting the crystal resonator element 12 by energizing the probe pin while the probe pin constituting the frequency measuring device is in contact with the measuring device (not shown). Means.
FIGS. 2A and 2B are explanatory views of the configuration and measurement state of the probe pin 40 according to the embodiment of the present invention, and the probe pin 40 is recessed in a distal end surface in contact with the adjustment terminal 30. FIG. The structure provided with the recessed part 41 is characteristic.
In the present invention, by providing a concave recess 41 on the tip surface of the probe pin 40, the outer peripheral edge 41a of the probe pin recess avoids the central portion of the adjustment terminal 30 having a shape in which the central portion bulges. Therefore, it is possible to increase the measurement accuracy by increasing the contact area and the contact stability as compared with the conventional probe pin having a flat tip surface.

Next, FIG. 3 is a diagram showing an embodiment according to two adjustment terminals that form a pair.
First, a feature common to each of the adjustment terminals 30 in FIGS. 3A and 3B is a configuration in which a plurality of strip portions 31 extend radially from the center portion C. In other words, the adjustment terminal 30 has a configuration in which a plurality of strip portions 31 are crossed.
The adjustment terminal 30 in FIG. 3A has a cross-shaped configuration. Since the two adjustment terminals 30 form a pair, two cross-shaped adjustment terminals are illustrated.
The adjustment terminal 30 in FIG. 3B has a Y-shaped configuration.
Since these adjustment terminals 30 are formed by applying a conductive material such as tungsten to the package surface using a screen printing method, the adjustment terminals 30 are rounded under the influence of surface tension in the fluid state immediately after application. .
For example, FIGS. 4A and 4B are vertical cross-sectional views of the cross-shaped adjustment terminal of FIG. 3A, and the vertical cross-sectional shape of the adjustment terminal 30 is closer to a hemispherical shape. If the probe pin 40 of the present invention shown in FIG. 2 is used, the distal end surface becomes a recessed portion 41. For example, in FIG. 3A, the outer peripheral edge 41a of the distal end surface of the probe pin is shown in FIG. Since it is possible to make close contact with the belt-like portion 31 of the book at a total of four locations, electrical continuity can be reliably ensured. Further, the outer peripheral edge portion 41a of the probe pin 40 can be brought into close contact with the adjustment terminal 30 in FIG.

Next, FIGS. 5A and 5B show a configuration example of an adjustment terminal according to another embodiment of the present invention. The common feature of both the adjustment terminals 30 is a space 33 at the center. It is in the point comprised by the cyclic | annular form provided with. Even when the tip end surface of the probe pin 40 of the present invention is brought into contact with the adjusting terminal 30, the outer peripheral edge portion 41a of the tip end surface of the probe pin is formed with the annular conductor portion 32 and the whole because the tip end surface is recessed. Therefore, it is possible to make contact in a close contact state, and to ensure electrical continuity reliably.
Further, since the area of the adjustment terminal shown in FIG. 5 is much narrower than that of the conventional rectangular adjustment terminal, the parasitic capacitance can be reduced.
In the above-described embodiment, a crystal oscillator is illustrated as a typical example of a piezoelectric oscillator. However, the present invention can be applied to all oscillators using piezoelectric vibration elements made of other piezoelectric materials.

(A) And (b) is a surface mount type piezoelectric device having a package structure having an adjustment terminal (monitor electrode pad) for making a frequency measurement by contacting the tip of a probe pin according to an embodiment of the present invention. The longitudinal cross-sectional view and bottom view of the crystal oscillator as an example of an oscillator. (A) and (b) are explanatory drawing of the structure of the probe pin which concerns on embodiment of this invention, and a measurement state. (A) And (b) is a figure which shows embodiment of the terminal for adjustment which makes a pair by two each. (A) And (b) is a figure which shows embodiment which concerns on the terminal for adjustment which makes a pair by two. (A) And (b) is a figure which shows the structural example of the terminal for adjustment which concerns on other embodiment of this invention. The figure explaining the fault of the conventional probe.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Insulation container, 2 ... Upper surface side recess, 3 ... Lower surface side recess, 3a ... Ceiling surface 4 ... Bottom surface, 5 ... Each mounting terminal, 6 ... Lower surface side internal pad, 11 ... Upper surface side internal pad, 12 ... Crystal Vibrating element, 15 ... Metal lid, 20 ... IC component, 30 ... Each adjustment terminal, 31 ... Band-shaped part, 32 ... Conductor part, 33 ... Space, 40 ... Probe pin, 41 ... Recessed part, 41 ... Recessed part, 41a ... outer peripheral edge

Claims (7)

For a piezoelectric vibration element that is disposed on the inner surface of the recess for the IC component of a package having a recess for accommodating the piezoelectric vibration element and a recess for accommodating an IC component that constitutes an oscillation circuit, and is electrically connected to the piezoelectric vibration element. In the probe pin for measuring the frequency by bringing the tip part into contact with the monitor electrode pad,
A probe pin characterized in that a concave portion recessed in a concave shape is provided on a tip surface of the probe pin. A recess for housing the piezoelectric vibration element, a recess for housing an IC component constituting the oscillation circuit, and a monitor electrode pad for the piezoelectric vibration element disposed on the inner surface of the recess for the IC component and conducting with the piezoelectric vibration element In a surface mounting package comprising:
The monitor electrode pad has a configuration in which a plurality of band-like portions extend radially from a central portion.   The monitor electrode pad according to claim 2, wherein the monitor electrode pad has a cross-shaped configuration.   The monitor electrode pad according to claim 2, wherein the monitor electrode pad has a Y-shaped configuration. A recess for housing the piezoelectric vibration element, a recess for housing an IC component constituting the oscillation circuit, and a monitor electrode pad for the piezoelectric vibration element disposed on the inner surface of the recess for the IC component and conducting with the piezoelectric vibration element In a surface mounting package comprising:
The monitor electrode pad is configured to have an annular shape.   A package for surface mounting, comprising the monitor electrode pad according to claim 2.   The surface-mount piezoelectric oscillator, wherein the piezoelectric vibration element and the IC component are accommodated in the respective recesses of the surface-mount package according to claim 6.

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