JP2001308490A - Terminal electrode of surface mounting electronic component and quartz oscillator employing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mounting component, especially a surface mounting oscillator, which enhances bonding strength to a circuit board. SOLUTION: In the terminal electrode made of a conductive material provided on the bottom face of a surface mounting electronic component, protrusions and recesses are provided on the surface of the conductive material. The surface mounting electronic component is a crystal oscillator having at least a quartz piece in a container body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal electrode of a surface-mounted electronic component (hereinafter referred to as a surface-mounted component) and a crystal oscillator using the same, and more particularly to a crystal oscillator adapted to miniaturization.

[0002]

2. Description of the Related Art Crystal oscillators are widely used as various frequency and time reference sources in various electronic devices including communication devices. In such a situation, a surface-mounted crystal oscillator (hereinafter referred to as a surface-mounted oscillator) is used for a small electronic device, particularly a mobile phone, and the success or failure of miniaturization determines commercialization.

(Example of Prior Art) FIGS. 3 and 4 are views of a surface mount oscillator for explaining an example of a conventional example. FIG. 3 is a sectional view and FIG. 4 is a bottom view. The surface mount oscillator includes a crystal body 2, an IC chip 3, and a capacitor 4 that constitute an oscillation circuit housed in a container body 1 made of a laminated ceramic, and a cover 5 is joined. The IC chip 3 is fixed to the bottom surface of the container body 1, and the crystal blank 2 is fixed to a step on both sides of one end of a lead electrode extending from an excitation electrode (not shown). Then, terminal electrodes 6 for surface mounting are formed on the four corners of the back surface and side surfaces of the container body 1.

[0004]

[Problems to be Solved by the Invention]
However, in such a device, if the current outer shape (length × width is 5 × 3.2 mm) is further reduced, the terminal electrode 6 for surface mounting becomes too small, and the connection strength with the circuit board on which it is mounted is reduced. Could be jeopardized. In particular, since the surface-mounted oscillator has the terminal electrodes 6 at the four corners of the container main body 1, if the width direction is further narrowed, there is a risk of an electrical short circuit between the terminal electrodes 6, and the terminal electrodes 6 need to be kept small. There is.

(Object of the Invention) The present invention provides a surface mount component, particularly a surface mount oscillator, which maintains the bonding strength.

[0006]

According to the present invention, a basic solution is to provide the terminal electrodes 6 for surface mounting with irregularities.

[0007]

According to the present invention, since the terminal electrodes 6 are provided with irregularities, the bonding area to the circuit board is increased. Hereinafter, an embodiment of the present invention will be described using a surface-mounted oscillator as an example.

[0008]

1 and 2 are views of a surface mount oscillator for explaining an embodiment of the present invention. FIG. 1 is a partial sectional view for explaining a terminal electrode, and FIG. 2 is a bottom view. is there. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted. As described above, the surface mount oscillator has the IC chip 3 fixed to the bottom surface of the container body 1, the both ends of the crystal blank 2 fixed to the stepped portion, and the cover 5 joined thereto (see FIG. 3).

[0009] Of the terminal electrodes 6 provided at the four corners of the container body 1, particularly the terminal electrodes on the back surface (hereinafter referred to as back surface electrodes) 6
Is provided with irregularities. For example, when W (tungsten) as a base electrode is formed by printing on the back surface of the bottom wall layer 1a of the laminated ceramic, the two layers 6 are formed.
(Ab). That is, the first layer 6a is flattened. Then, the second layer 6b is formed using a mask having holes vertically and horizontally, and integrated with the container body 1 by firing.

After firing, for example, N
Au (gold) is laminated on i (nickel) and, if necessary, Ni (not shown). These Ni and Au are formed by electrolytic plating. As a result, irregularities of about 50 μm are formed on the surface of the back electrode 6 vertically and horizontally.

With such a configuration, the surface of the back electrode 6 of the container body 1 has irregularities, so that the surface area is increased. Therefore, for example, when mounting on a circuit board by soldering or the like, the bonding area with solder is increased, so that the connection strength can be increased even if the back surface electrode 6 is reduced.

In addition, since the back electrode 6 can be kept small even when the container body 1 is downsized, an electrical short circuit particularly in the width direction is prevented. For these reasons, the size reduction of the surface mount oscillator can be further promoted.

[0013]

[Others] In the above embodiment, the unevenness of the back electrode 6 is formed vertically and horizontally. However, it may be striped, extremely concave or convex, and can be formed arbitrarily by a mask shape. I just need. Further, although the description has been given by applying the invention to the crystal oscillator, for example, a crystal resonator or a crystal filter in which the terminal electrodes 6 are provided at four corners can provide the same effect as that of the embodiment. Furthermore, the present invention can be applied to a surface mount component having terminal electrodes 6 on both sides, such as a capacitor and a resistor.

Although the container body 1 is made of a laminated ceramic, the present invention can be applied to a case where each component is mounted on a glass epoxy board, for example. Although the irregularities are formed by printing using a mask, the irregularities may be provided by surface roughening after baking, and plated with Ni or the like. Further, although the surface is made of Au, any conductive material that becomes an electrode may be used.

[0015]

According to the present invention, since the terminal electrodes 6 for surface mounting are provided with irregularities, it is possible to provide a surface mounting component, particularly a surface mounting oscillator, which maintains the bonding strength.

[Brief description of the drawings]

FIG. 1 is a diagram of a surface-mounted oscillator illustrating one embodiment of the present invention, and is a partial cross-sectional view particularly illustrating a terminal electrode.

FIG. 2 is a diagram of a surface-mounted oscillator illustrating one embodiment of the present invention, and is a bottom view particularly illustrating terminal electrodes.

FIG. 3 is a cross-sectional view of a surface mount oscillator illustrating a conventional example.

FIG. 4 is a bottom view of a surface mount oscillator illustrating a conventional example.

[Explanation of symbols]

1 container body, 2 crystal pieces, 3 IC chips, 4 capacitors, 5 covers, 6 terminal electrodes.

Claims (2)

[Claims] 1. A terminal electrode comprising a conductive material provided on a bottom surface of an electronic component for surface mounting, wherein the surface of the conductive material is provided with irregularities. 2. A crystal oscillator wherein said surface-mounting electronic component contains at least a crystal piece in a container body.