JP3685683B2 - Crystal oscillator for surface mounting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crystal oscillator for surface mounting (hereinafter referred to as a surface mount oscillator) in the industrial application field, and particularly to a crystal oscillator having terminal electrodes corresponding to miniaturization.
[0002]
[Prior art]
BACKGROUND OF THE INVENTION Crystal oscillators are widely used in various electronic devices including communication devices as a frequency and time reference source. Under such circumstances, surface-mounted oscillators are used for small electronic devices such as mobile phones, and the success or failure of miniaturization determines the commercialization.
[0003]
(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 container body 1 made of a multilayer ceramic, housing a crystal piece 2, an IC chip 3, and a capacitor 4 constituting an oscillation circuit, and a cover 5 bonded thereto. The IC chip 3 is formed on the bottom surface of the container body 1, and the crystal piece 2 is formed by fixing both ends of one end portion of the extraction electrode extending from an excitation electrode (not shown) to the stepped portion. And the terminal electrode 6 for surface mounting is formed in the back surface and side surface used as the four corners of the container main body 1. FIG.
[0004]
[Problems to be solved by the invention]
(Problem of the prior art) However, in such a case, when 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 is mounted. The connection strength with the circuit board may be jeopardized. In particular, since the surface mount oscillator has the terminal electrodes 6 at the four corners of the container body 1, there is a risk of an electrical short circuit between the terminal electrodes 6 when the interval in the width direction is further narrowed, and the terminal electrodes 6 need to be kept small. There is.
[0005]
SUMMARY OF THE INVENTION The present invention provides a surface mount oscillator that maintains bonding strength.
[0006]
[Means for Solving the Problems]
In the present invention , an IC chip and a crystal piece are accommodated in a container body made of a multilayer ceramic , and a base electrode made of W is formed by printing and baking at the four corners of the back surface of the container main body, and on the base electrode in the crystal oscillator for surface mounting with a terminal electrode surface layer consisting of N i and a u by electrolytic plating is provided, wherein the base electrode has at least a first layer and a second layer from said back surface, said first layer Is flat and the second layer is provided with a plurality of holes vertically and horizontally, and the surface of the terminal electrode has irregularities vertically and horizontally .
[0007]
[Action]
In the present invention, since the vertical and horizontal irregularities are provided on the surface of the terminal electrode, the bonding area to the circuit board is increased. Hereinafter, an embodiment of the present invention will be described using a surface mount oscillator as an example.
[0008]
【Example】
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. In addition, the same number is attached | subjected to the part same as a prior art example figure, and the description is simplified or abbreviate | omitted.
As described above, the surface-mounted oscillator is formed by bonding the IC chip 3 to the bottom surface of the container body 1, fixing one end of the crystal piece 2 to the stepped portion, and bonding the cover 5 (see FIG. 3 above).
[0009]
Of the terminal electrodes 6 provided at the four corners of the container body 1, in particular, the terminal electrode 6 (referred to as the back electrode) on the back surface is provided with irregularities. For example, when W (tungsten) as a base electrode is formed on the back surface of the bottom wall layer 1a of the laminated ceramic by printing, these are formed into two layers 6 (ab). That is, the first layer 6a is made flat. And the 2nd layer 6b is formed using the mask which has a hole vertically and horizontally, and unites with the container main body 1 by baking.
[0010]
Then, after firing, for example, Ni (nickel) is laminated on the terminal electrode 6 and Au (gold) is laminated on Ni as necessary (not shown). These Ni and Au are formed by electrolytic plating. As a result, irregularities of about 50 μ are formed vertically and horizontally on the surface of the back electrode 6.
[0011]
With such a configuration, since the surface of the back electrode 6 of the container body 1 has irregularities, the surface area is increased. Therefore, for example, when mounting on a circuit board with solder or the like, the bonding area with the solder is increased, so that the connection strength can be increased even if the back electrode 6 is reduced.
[0012]
Moreover, since the back surface electrode 6 can be kept small even if the container main body 1 is reduced in size, an electrical short circuit in the width direction is particularly prevented. For these reasons, it is possible to further promote downsizing of the surface mount oscillator.
[0013]
【The invention's effect】
In the present invention , an IC chip and a crystal piece are accommodated in a container body made of a multilayer ceramic , and a base electrode made of W is formed by printing and baking at the four corners of the back surface of the container main body, and on the base electrode in the crystal oscillator for surface mounting with a terminal electrode surface layer consisting of N i and a u by electrolytic plating is provided, wherein the base electrode has at least a first layer and a second layer from said back surface, said first layer Is flat and the second layer is provided with a plurality of holes in the vertical and horizontal directions, and the surface of the terminal electrode has irregularities in the vertical and horizontal directions, so that it is possible to provide a surface-mounted component, particularly a surface-mounted oscillator, that maintains the bonding strength.
[Brief description of the drawings]
FIG. 1 is a diagram of a surface-mount oscillator for explaining an embodiment of the present invention, particularly a partial cross-sectional view for explaining a terminal electrode.
FIG. 2 is a view of a surface-mount oscillator for explaining an embodiment of the present invention, particularly a bottom view for explaining a terminal electrode.
FIG. 3 is a cross-sectional view of a surface mount oscillator for explaining a conventional example.
FIG. 4 is a bottom view of a surface-mount oscillator for explaining a conventional example.
[Explanation of symbols]
1 container body, 2 crystal piece, 3 IC chip, 4 capacitor, 5 cover, 6 terminal electrode.

Claims (1)

An IC chip and a crystal piece are accommodated in a container body made of multilayer ceramic, and base electrodes made of W are formed by printing and firing at the four corners of the back surface of the container body, and electroplating is performed on the base electrode. in the crystal oscillator for surface mounting with a terminal electrode surface layer consisting of N i and a u is provided, wherein the base electrode has at least a first layer and a second layer from said back surface, said first layer is said as a flat the second layer is set only be with a plurality of holes in a matrix, a surface-mount crystal oscillator which is characterized by having irregularities vertically and horizontally on the surface of the terminal electrode.

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