JP2010154481A - Crystal device for surface mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal device for surface mount that can form a solder fillet from each side surface by increasing junction strength. <P>SOLUTION: In a crystal device for surface mount in which at least a crystal piece 6 is housed and tightly sealed in a container body 1 which is formed of laminated ceramic and has a bottom wall 1a and a frame wall 1b, and which has mount terminals 4 having end-surface electrodes 4a for forming solder fillets at four corners of an outer bottom surface of the container body 1, the end-surface electrodes 4a are so constituted as to be formed on both side surfaces adjacent to each other with the four corners sandwiched. According to such a constitution, since there are the end-surface electrodes on the adjacent side surfaces from each mount terminal 4 at the four corners, it is possible to visually confirm the solder fillets from directions that meet each other at right angles and increases the fixing strength with the solder fillets. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface mount crystal device, and more particularly to an end face electrode for forming a solder fillet.

(Background of the Invention)
Surface mount crystal devices such as crystal resonators (hereinafter referred to as surface mount resonators) are small and light, so they are built in, for example, portable electronic devices along with oscillation circuits as frequency and time reference sources. The

(Example of conventional technology)
FIGS. 4 and 5 are views of a surface-mount resonator for explaining a conventional example. FIG. 4 (a) is a sectional view, FIGS. (B and c) are outer bottom views, and FIG. FIG.

  The surface-mounted vibrator is formed by accommodating a crystal piece 6 in a container body 1 and sealingly enclosing a metal cover 2 on an opening end face. The container body 1 is made of a laminated ceramic having a bottom wall 1a and a frame wall 1b, and has a rectangular shape in plan view with the cross-sectional shape being concave. The container main body 1 has crystal holding terminals 3 on both sides at one end, mounting terminals 4 on the four corners of the outer bottom, and a metal film 5 on the upper surface of the frame wall 1b serving as an opening end surface.

  The crystal piece 6 has excitation electrodes 7a on both main surfaces, and extends extraction electrodes 7b on both sides of one end (FIG. 5). Then, both sides of one end of the crystal piece 6 from which the extraction electrode 7b extends are fixed to the crystal holding terminal 3 on the inner bottom surface by the conductive adhesive 8, and are electrically and mechanically connected. The crystal holding terminal 3 is electrically connected to, for example, a pair of diagonal mounting terminals 4 through the laminated surface and the end surface electrode 4a.

  A seal ring 9 is joined to the metal film 5 on the upper surface of the frame wall 1b serving as the opening end face by silver brazing, and the metal cover 2 is joined to the seal ring 9 by seam welding. The metal film 5 is electrically connected to the mounting terminals 4 of the other diagonal portion through the through-electrodes and the laminated surface (not shown) of the frame wall 1b. In these cases, the end surface electrode 4a of the mounting terminal 4 at the four corners is, for example, “FIG. 4 (b)” on the outer surface of the pair of opposing sides, “(C)” is formed.

  In these cases, as shown in FIG. 6, in the state of the bottom wall sheet 1A in which the bottom walls 1a are gathered, through holes (through holes) 10 are formed in the four corners adjacent to the bottom walls 1a. Provide. Then, a base electrode (not shown) of the end face electrode 4a is formed together with the crystal holding terminal 3 and the mounting terminal 4 by printing tungsten (W) or molybdenum (Mo).

  Next, in the same manner, a frame wall sheet (not shown) in which a metal film 5 is formed on the upper surface of the frame wall and a base electrode of a through electrode is formed in the frame wall is laminated on the bottom wall sheet 1A and integrally formed as a container body sheet. Bake. For example, after a seal ring 9 (metal body) is fixed to each container body 1 of the container body sheet, Ni (nickel) and Au (gold) are sequentially formed on the exposed base electrode by electroplating. Finally, the container body 1 sheet is divided vertically and horizontally along the lines AA and BB to obtain individual container bodies 1.

  In addition, when forming the end surface electrode 4a in the outer surface of a pair of opposing side of the bottom wall 1a, the through-hole 10 formed in the bottom wall sheet 1A is made into a long thin rectangle or an oval shape, as shown in FIG. "If it is formed at the four corners, it is a circle" (Fig. 5B). And when dividing | segmenting into each container main body 1, the rectangular (oval) shape and circular through-hole are divided into 4 parts. The through hole 10 is formed in both the bottom wall 1a and the frame wall 1b, and the end face electrode 4a is only the bottom wall 1a.

Then, the mounting terminals 4 of the surface mounting vibrator are joined to the circuit terminals 12 of the set substrate 11 by, for example, solder 13 containing lead-free and electrically and mechanically connected (solder reflow). In this case, the melted solder crawls up to the end face electrode 4a to form a so-called solder fillet. Since the melted state of the solder 13 can be confirmed by forming a solder fillet, the end face electrode 4a is useful. Further, the bonding strength can be increased by the solder fillet.
JP 2007-104705 A JP 2004-153451 A

(Problems of conventional technology)
However, in the surface-mounted vibrator having the above-described configuration, the area of the mounting terminal 4 on the outer surface becomes smaller and the bonding strength decreases as the size is reduced. When the rectangular end face electrode 4a is provided on one set of opposing sides, the area of the end face electrode 4a can be increased to increase the bonding strength. Fillet formation cannot be confirmed.

  In addition, when the end face electrode 4a is provided in the vertical ridge line portion of the four corners, the formation of the solder fillet can be confirmed from any side face, but the end face electrode 4a becomes a ¼ arc so that the surface area is small. Therefore, there is a problem that the meaning of increasing the bonding strength is weakened.

(Object of invention)
An object of the present invention is to provide a surface-mount crystal device capable of increasing the bonding strength and forming solder fillets from the respective side surfaces.

  According to the present invention, as shown in the claims (Claim 1), at least a crystal piece is accommodated in a container body made of a laminated ceramic having a bottom wall and a frame wall and hermetically sealed. In a surface-mount crystal device having a mounting terminal having a solder fillet-forming end face electrode at the four corners of the bottom surface, the end face electrodes are formed on both side surfaces adjacent to each other across the four corners. .

  With such a configuration, since the end face electrode is provided on the side surface adjacent to each mounting terminal 4 at the four corners, the solder fillet can be visually recognized from directions orthogonal to each other, and the fixing strength by the solder fillet can be increased.

(Embodiment section)
According to a second aspect of the present invention, in the first aspect, the end face electrodes on both side surfaces adjacent to each other are formed continuously. Thereby, the adhesion strength by the solder fillet can be further increased.

  FIGS. 1A and 1B are views of a surface-mounted vibrator for explaining an embodiment of the present embodiment. FIG. 1A is an outer bottom view and FIG. 1B is a plan view of a bottom wall sheet. 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.

  The surface mount vibrator (see FIG. 4), as described above, accommodates the crystal piece 6 in the container body 1 having the bottom wall 1a and the frame wall 1b, and joins the metal cover 2 to the opening end face by seam welding. And hermetically sealed. The container main body 1 has crystal holding terminals 3 on both sides at one end, mounting terminals 4 on the four corners of the outer bottom, and a metal film 5 on the upper surface of the frame wall 1b serving as an opening end surface. The crystal holding terminal 3 is electrically connected to, for example, a pair of diagonal mounting terminals 4 through the laminated surface and the end surface electrode 4a. The metal cover 2 (metal film 5) is electrically connected to the mounting terminals 4 in the other diagonal portion through the through electrodes and end face electrodes 4a of the frame wall 1b.

  And in this embodiment, the end surface electrode 4a of the bottom wall 1a connected with each mounting terminal 4 of the outer bottom face (4 corner | angular part) of the container main body 1 is formed in all the adjacent outer surfaces. In this example, the end surface electrodes 4a on the adjacent outer surfaces are formed continuously. These are formed by laminating a bottom wall sheet 1a and a frame wall sheet (not shown), each of which collects the bottom wall 1a and the frame wall 1b.

  For example, first, cross-shaped through-holes (through holes) 10 are provided at the four corners adjacent to the bottom walls 1a of the bottom wall sheet 1a. Then, as described above, the base electrode of the end surface electrode 4a is formed on the inner peripheral surface of the through hole together with the crystal holding terminal 3 and the mounting terminal 4 by printing tungsten (W) or molybdenum (Mo).

  Next, a container body sheet in which a frame wall sheet is laminated on the bottom wall sheet 1A is laminated and a seal ring is provided on the opening end face, and then Ni and Au are formed on the base electrode by electroplating. Finally, it divides | segments into each container main body 1, and the end surface electrode 4a is obtained on the outer side surface adjacent from each mounting terminal 4. FIG. The end surface electrode 4a is continuous between adjacent outer surfaces. Then, a crystal piece 6 is hermetically sealed in the container body 1 to form a surface mount vibrator, and mounted on a set substrate (not shown) by solder reflow.

  With such a configuration, the end face electrodes 4a are provided on the side surfaces adjacent to the mounting terminals 4 provided at the four corners of the outer bottom surface of the surface mount vibrator. Therefore, at the time of fixing to the set substrate by solder reflow, the molten solder crawls up to the adjacent side surface to form a solder fillet. Thereby, the formation of the solder fillet can be confirmed from the side surfaces orthogonal to each other, and the bonding strength by the solder fillet can be increased.

(Other matters)
In the above embodiment, the end surface electrode 4a formed on the outer side surface adjacent to each mounting terminal 4 is continuous. However, for example, as shown in FIG. It can also be formed independently. In this case, for example, a circular through hole 10 is provided on each adjacent side of each bottom wall 1a of the bottom wall sheet 1A, and the bottom wall sheet 1A is divided and formed after firing.

  Further, the surface-mount vibrator has been described as an example. However, for example, as shown in FIG. 3, the same applies to the case where the IC chip 14 is accommodated together with the crystal piece 6 to form a surface-mount oscillator. Any crystal device including the mounting terminal 4 having the end face electrode 4a on the outer bottom surface of the substrate can be applied.

It is a figure of the surface mount vibrator explaining one Embodiment of a present Example, The figure (a) is an outer bottom view, The figure (b) is a top view of a bottom wall sheet | seat. It is a figure of the surface mount vibrator explaining other examples of the present invention, the figure (a) is an outer bottom view, and the figure (b) is a top view of a bottom wall sheet. It is sectional drawing of the surface mount oscillator explaining the other application example of this invention. FIG. 4A is a cross-sectional view and FIG. 4B and FIG. 4B are outer bottom views of a surface-mounted vibrator for explaining a conventional example. It is a top view of the crystal piece explaining a prior art example. It is a figure explaining a prior art example, and the same figure (a, b) is a top view of a bottom wall.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Container body, 2 Cover, 3 Crystal holding terminal, 4 Mounting terminal, 5 Metal film, 6 Crystal piece, 7 Excitation and extraction electrode, 8 Conductive adhesive, 9 Seal ring, 10 Through-hole, 11 Set board, 12 Circuit Terminal, 13 solder, 14 IC chip.

Claims (2)

  A container main body made of a multilayer ceramic having a bottom wall and a frame wall contains at least a crystal piece and hermetically sealed, and includes mounting terminals having end face electrodes for forming solder fillets at four corners of the outer bottom surface of the container main body. In the surface mount crystal device, the end face electrode is formed on both side surfaces adjacent to each other across the four corners.   2. The surface-mount crystal device according to claim 1, wherein the end face electrodes on both side surfaces adjacent to each other are continuously formed.