JP2010109535A - Method of mounting surface mounting crystal oscillator onto set substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of mounting a surface mounting crystal oscillator onto a set substrate, by which an electric short circuit between a communication terminal and a circuit terminal is prevented. <P>SOLUTION: The surface mounting crystal oscillator, for which an IC chip and a crystal chip are housed in a recessed container body 1, mounting terminals 5 are provided on four corners on the outer bottom of the container body 1, and communication terminals 6a and 6b are provided on the outer side of the container body 1 between the mounting terminals 5 at the four corners, is provided. In the method of mounting the surface mounting crystal oscillator to the set substrate, the surface mounting crystal oscillator is fixed to circuit terminals 8 which are larger than the mounting terminals 5 on the outer bottom and cover the mounting terminals 5 with a conductive bonding material. The circuit terminals 8 at both corners holding the communication terminals 6a and 6b there between on the set substrate are notched at the corner on the outer peripheral side facing each other, respectively, are made away from the communication terminals 6a and 6b, and are fixed covering the mounting terminals 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mounting method of a surface-mounted crystal oscillator (hereinafter referred to as a surface-mounted oscillator) on a set substrate, and more particularly to a mounting method of a surface-mounted oscillator that has a communication terminal and prevents an electrical short circuit.

(Background of the Invention)
Since the surface-mounted oscillator is small and light, it is used as a frequency and time reference source in portable electronic devices such as mobile phones. One of such devices is provided with a communication terminal such as a write terminal for writing temperature compensation data and a crystal inspection terminal for inspecting the vibration characteristics of the crystal resonator.

(Example of conventional technology)
3 and 4 are views of a surface-mount oscillator for explaining a conventional example. FIG. 4A is a side view of a partial cross section in the long side direction, and FIG. 4 is a short view of the surface-mount oscillator with respect to a set substrate. It is a side view of a side direction.

  The surface mount oscillator is formed by, for example, fixing an IC chip 2 to an inner bottom surface of a container body 1 having a concave shape, fixing both ends of one end of a crystal piece 3 to an inner wall step portion, and bonding a metal cover 4 to an opening end surface. The metal cover 4 is joined to a metal ring (not shown) provided on the opening end surface of the container body 1 by, for example, seam welding.

  The container body 1 is made of a laminated ceramic, and has mounting terminals 5 at the four corners of the outer bottom surface. Both the container body 1 and the mounting terminal 5 are rectangular in a direction, and the long side direction (short side direction) of the container body 1 and the mounting terminal 5 is orthogonal to each other by a de facto standard. A communication terminal 6 is provided in the central region of each outer surface between the mounting terminals 5.

  The communication terminal 6 includes, for example, a crystal inspection terminal 6b for inspecting vibration characteristics of a crystal resonator (crystal piece 3) and a write terminal 6a for writing temperature compensation data. Here, for example, a pair of write terminals 6a are provided on the outer side that is the long side, and a pair of crystal inspection terminals 6b are provided on the outer side that is the short side.

  The IC chip 2 integrates at least an oscillation circuit (not shown) and a temperature compensation mechanism, and the IC terminal on the circuit function surface is fixed to the inner bottom surface using the bumps 7 by ultrasonic thermocompression bonding. The power supply, ground, output terminal, and the like in the IC terminal are electrically connected to the mounting terminal 5 on the outer bottom surface (four corners) through the laminated surface and the corner through holes. Further, the write terminal in the IC terminal is electrically connected to the corresponding communication terminal 6 (write terminal 6a) on the outer surface.

  The quartz crystal piece 3 is fixed to the step portion at both ends of the lead electrode extending from the excitation electrode (not shown) on both main surfaces. And while electrically connecting to the crystal terminal in an IC terminal, it electrically connects to the communication terminal 6 (crystal inspection terminal 6b) of an outer surface. All of the communication terminals 6 are provided by through-hole processing on the outer surface serving as a central region between the mounting terminals 5. In this case, the communication terminal 6 is formed except for the lowermost layer and the uppermost layer of the multilayer ceramic in order to prevent an electrical short circuit, and the uppermost layer and the lowermost layer are electrodeless layers provided with depressions by through holes. And

And it mounts by the solder reflow which conveys a high heat path with respect to the set board | substrate which is not shown in figure. In this case, the circuit terminal 8 indicated by the alternate long and short dash line of the set substrate corresponding to the mounting terminal 5 of the container body 1 is formed to be larger than and cover the mounting terminal 5. Then, cream solder by printing (including lead-free solder) is applied onto the circuit terminals 8 and joined by solder reflow.
JP 2008-78791 A

(Problems of conventional technology)
However, in the surface-mounted oscillator having the above configuration, as the miniaturization progresses (for example, 2.5 × 2 mm or less), the distance between the mounting terminals 5 particularly in the short side direction becomes shorter. It becomes narrower.

  The circuit terminal 8 of the set substrate 9 is larger than the mounting terminal 5 and is fixed so as to cover it. Therefore, the space between the circuit terminal 8 and the communication terminal 6 (crystal inspection terminal 6b) is further narrowed. For this reason, there has been a problem that the molten solder 10 or fine dust or the like applied to the circuit terminal 8 at the time of solder reflow contacts the communication terminal 6 to cause an electrical short circuit.

  In this case, since the communication terminal 6 on the short side that faces is used as the crystal inspection terminal 6b, the crystal piece 3 and the mounting terminal 5 are connected to stop the oscillation. Further, when the short-side communication terminal 6 is the write terminal 6a, problems such as an increase in the stray capacitance or the like, and a change in circuit constants to make the oscillation characteristics out of specification.

(Object of invention)
It is an object of the present invention to provide a method for mounting a surface mount oscillator on a set substrate that prevents an electrical short circuit between a communication terminal and a circuit terminal.

  In the present invention, as shown in the claims (Claim 1), the IC chip and the crystal piece are accommodated in a concave container body, and mounting terminals are provided at the four corners on the outer bottom surface of the container body. A surface-mount crystal oscillator having a communication terminal on the outer surface of the container body between the mounting terminals at the four corners, and the surface-mount crystal oscillator is larger than the mounting terminal on the outer bottom surface and the mounting terminal In the mounting method of the surface-mounted crystal oscillator to the set substrate fixed to the circuit terminal covered with the conductive bonding material, the circuit terminals at both corners sandwiching the communication terminal of the set substrate are the corners on the outer peripheral side of the inner periphery facing each other. A portion is cut away from the communication terminal, and the mounting terminal is covered and fixed.

  With such a configuration, since the opposite corners of the circuit terminals at both corners sandwiching the communication terminal are cut away, the gap with the communication terminal is increased. Therefore, it is possible to prevent an electrical short circuit due to a conductive bonding material or fine dust when the solder is melted. Even if the conductive bonding material is, for example, a thermosetting conductive adhesive, it is possible to prevent a short circuit during application in a molten state.

(Embodiment section)
According to a second aspect of the present invention, in the first aspect, the container body and the mounting terminal are formed in a rectangular shape that is long in one direction, and the length direction of the container body and the width direction of the mounting terminal are orthogonal to each other. Thus, the configuration of claim 1 is made concrete in accordance with the prior art.

  In the second aspect of the present invention, in the first aspect, the communication terminal is a temperature compensation data writing terminal or a crystal inspection terminal. This makes the communication terminal clear. Note that the write terminal does not write data but includes exchange of data relating to temperature compensation.

  FIGS. 1 and 2 are exploded views of a set substrate for explaining an embodiment of the present embodiment, and FIG. 2 is a cross-sectional view of the set substrate in the short side direction. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.

  As described above, the surface-mounted oscillator has the mounting terminals 5 on the outer bottom surface of the container body 1 that contains the IC chip 2 and the crystal piece 3 and is hermetically sealed. The communication terminal 6 is provided between the two. Of the communication terminals 6, the writing terminal 6a is provided on the opposite outer surface in the length direction, and the crystal inspection terminal 6b is provided on the outer surface in the width direction.

  In this embodiment, the circuit terminals 8 of the set substrate 9 corresponding to the mounting terminals 5 on the outer bottom surface of the container body 1 are particularly opposed to each other with the communication terminals 6 (crystal inspection terminals 6b) in the width direction facing each other. A notch 10 is provided around the periphery. The notch 10 is formed by cutting off the corners on the outer peripheral side of the opposed inner peripheral pieces. As a result, the opposing corner of the circuit terminal 8 is separated from the crystal inspection terminal 6b.

  Even in this case, the circuit terminal 8 is larger than the mounting terminal 5, and the cutout portion 10 covers the mounting terminal 5. Then, as described above, the mounting terminals 5 of the surface mount oscillator are fixed by solder reflow in which cream solder is applied to the circuit terminals 8 of the set substrate 9. As a result, the mounting terminal 5 in the short side direction and the crystal inspection terminal 6b as the communication terminal 6 are separated from each other and the gap is increased, so that an electrical short circuit due to molten solder or fine dust can be prevented.

(Other matters)
In the said embodiment, although the container main body 1 was made into the rectangular shape long in one direction, for example, a square may be sufficient, and when a communication terminal is provided in an outer surface and the adjacent mounting terminal 5 is approached, it is the point. Applicable. In addition, the communication terminal 6 is exemplified by the case where each pair of the write terminal 6a and the crystal inspection terminal 6b is provided on the outer surface, but it is needless to say that any one of them can be applied.

It is an exploded view with respect to the set board | substrate explaining one Embodiment of a present Example. It is sectional drawing of the short side direction with respect to the set board | substrate explaining one Embodiment of this invention. It is a side view of the partial cross section of the long side direction of the surface mount oscillator explaining a prior art example. It is a side view of the short side direction of the surface mount oscillator explaining a conventional example.

Explanation of symbols

  1 container body, 2 IC chip, 3 crystal piece, 4 metal cover, 5 mounting terminal, 6 communication terminal, 7 bump, 8 circuit terminal, 9 set substrate, 10 notch.

Claims (3)

  An IC chip and a crystal piece are accommodated in a container body having a concave shape, mounting terminals are provided at four corners on the outer bottom surface of the container body, and the outer side surface of the container body is between the mounting terminals at the four corners. A surface mount crystal oscillator having a communication terminal, and the surface mount crystal oscillator is fixed to a circuit terminal larger than the mount terminal on the outer bottom surface and covered with the mount terminal by a conductive bonding material. In the mounting method, the circuit terminals at both corners across the communication terminal of the set substrate are cut away from the outer peripheral corners on the inner periphery facing each other so as to be separated from the communication terminal and cover the mounting terminal. A method of mounting a surface-mounted crystal oscillator on a set substrate, wherein the set substrate is fixed.   2. The method of mounting a surface-mounted crystal oscillator according to claim 1, wherein the communication terminal is a temperature compensation data writing terminal or a crystal inspection terminal.   2. The method of mounting a surface-mounted crystal oscillator on a set substrate according to claim 1, wherein the container body and the mounting terminal are rectangular in shape in one direction, and the length direction of the container body and the width direction of the mounting terminal are orthogonal to each other. .

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