JP2009224741A - Package for electronic component and surface-mounted electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal oscillator that improves the connection strength between a package mounting terminal and land electrode of a circuit substrate and also prevents cracks from being caused. <P>SOLUTION: Packaging electrodes 5 are formed on substantially a rectangular-shaped bottom of the package 2 along two opposite bottom sides 2a, 2b. These packaging electrodes 5 are continuous with each internal pad 6, in a concave portion 3 corresponding thereto. A groove portion 7, to which an insulating substrate 4 of the package 2 is exposed, is formed on the packaging electrode 5 formed on the bottom of the package 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic component package that houses an electronic component therein, and a surface-mount electronic device that uses the electronic component package.

As surface-mount type electronic devices, for example, those in which various circuit components are mounted on the surface of a package having a mounting electrode at the bottom are known.
Examples of such surface mount electronic devices include piezoelectric devices such as crystal resonators, crystal filters, and crystal oscillators. A surface-mount type crystal resonator or crystal filter has a crystal resonator element (an element in which an excitation electrode is formed on a crystal substrate) mounted in a surface recess of a package having a mounting electrode at the bottom, and the crystal resonator element The concave portion on the insulating substrate is hermetically sealed with a metal lid.
FIGS. 9A and 9B are bottom views of the surface-mount type crystal resonator, respectively. In this crystal resonator 100, a crystal resonator element (not shown) is mounted in a surface recess of a package 101 having a mounting electrode 102 at the bottom, and the recess on the package 101 including the crystal resonator element is hermetically sealed by a metal lid 103. It is a stopped configuration. A concave chamfered portion (castellation) 105 is formed at each corner of the package 101 having a rectangular bottom shape. The conductor film formed in the chamfered portion 105 and each mounting electrode 102 are continuously formed. Conducted.
FIG. 9B shows another example of the bottom surface of the crystal resonator, and a castellation 105 is formed on each of two opposing side surfaces of the crystal resonator, and a conductor in each castellation 105 is formed. A rectangular mounting electrode 102 that is electrically connected to the film is formed on the bottom surface.

Patent Document 1 discloses a semiconductor device having a highly reliable connection point with respect to environmental changes such as thermal shock by making an insulating substrate into a circular shape.
Patent Document 2 discloses a package in which a stress applied to an optical semiconductor element is relieved by depositing a conductor of a component mounting portion in a product in a mesh shape or a stripe shape.
Patent Document 3 discloses an electronic component storage package in which a conductive film on a side surface and a terminal pad on a lower surface are separated.
In Patent Document 4, the corners of the mounting electrodes corresponding to the four corners of the bottom surface of the package are arc-shaped along the projecting arc shape, and the four corners of the bottom surface of the package have a protruding arc shape. A surface-mount type electronic device is disclosed in which the arc-shaped contour line at the corner of each mounting electrode has a shape along a circumference formed with a predetermined radius from the center point of the bottom surface of the package.
JP 2001-230338 A JP 2002-289957 A JP 2005-260124 A JP 2006-5027 A

FIG. 10 is an enlarged view of a main part showing a state in which the surface-mounted crystal resonator shown in FIG. 9 is solder-connected on a circuit board.
As shown in FIG. 10, the above-described conventional surface mount crystal resonator has a surface mount crystal resonator in the case where the mounting electrode 102 is connected to the land electrode 111 formed on the upper surface of the circuit board 110 by the solder 115. Due to the difference in thermal expansion coefficient between the package (for example, a ceramic substrate) 101 and the circuit board (for example, a glass epoxy substrate) 110 on the product side, a strong stress is applied to the solder 115 of the connection portion. In particular, as shown in FIG. 9, the farther the solder connection portion is from the center point C of the bottom surface of the crystal resonator package, the larger the mechanical stress is received.
For this reason, there is a possibility that a crack as shown in FIG. 10 may be formed in the solder connection portion far from the center point C depending on the use of the crystal resonator, the usage environment, and the installation location. In other words, when used in a harsh environment, such as when a crystal resonator is mounted on an in-vehicle circuit board, it is exposed to high and low temperatures in addition to vibration and impact. The durability of the solder connection due to the heat cycle becomes a problem. As one of the specifications required for the crystal unit, it is necessary to satisfy the requirements of the heat cycle test, but the stress is likely to be concentrated at one place on the solder connection portion farthest from the center point C of the package bottom surface. For this reason, cracks due to heat cycles are likely to occur in this portion, and defective products that do not satisfy the specifications may occur.
The present invention has been made in order to solve the above-described problem. An electronic component package capable of increasing the connection strength between a package mounting terminal and a land electrode of a circuit board and suppressing the occurrence of cracks, and the like. An object of the present invention is to provide a surface mount type electronic device using the above-mentioned.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
An electronic component package comprising an insulating substrate having a substantially rectangular bottom shape and a mounting electrode formed on the bottom surface of the insulating substrate, wherein a groove portion where the insulating substrate is exposed is provided at a required position of the mounting electrode. It is characterized by the formed electronic component package.

  In such a package for electronic components, when the mounting electrode and the land electrode of the circuit board are connected by solder, stress applied to the connecting portion can be relieved, so that the occurrence of cracks in the solder can be suppressed.

[Application Example 2]
The mounting electrode is characterized in that the electronic component package according to Application Example 1 is formed along two opposing bottom sides of the insulating substrate.

  In such an electronic component package, since the mounting electrode formed along two opposing bottoms of the insulating substrate and the land electrode of the circuit board are connected by solder, stress applied to the connecting portion can be relieved. It is possible to suppress cracks from occurring.

[Application Example 3]
The mounting electrode is characterized in that the electronic component package according to Application Example 1 is formed at each of the four corners of the bottom surface of the insulating substrate.

  In such an electronic component package, when the mounting electrodes formed at the four corners of the bottom surface of the insulating substrate and the land electrodes of the circuit board are connected by soldering, the stress applied to the connecting portion can be relieved, so that cracks occur in the solder Can be suppressed.

[Application Example 4]
The mounting electrode is divided into two electrode regions by a straight line passing through the center of the mounting electrode and parallel to two opposing bottoms of the insulating substrate formed so that the mounting electrodes are along each other. 3. The electronic component according to Application Example 2, wherein the groove is formed at a position where A> B where A is the area of one electrode region located on the center side and B is the area of the other electrode region. Features a package.

  In such an electronic component package, a groove is formed at a position far from the center of the package of the mounting electrode, so that the mounting electrode formed along two opposing bottom sides of the insulating substrate and the land electrode of the circuit board are formed. Since the stress applied to the connecting portion when connected by solder can be relieved, the occurrence of cracks in the solder can be suppressed.

[Application Example 5]
Of the vertices of the mounting electrode, the mounting electrode is divided into two electrode regions by a diagonal line connecting two vertices located on the edge side of the insulating substrate, and one electrode region located on the center side of the insulating substrate The electronic component package according to Application Example 3 is characterized in that the groove is formed at a position where A> B, where A is the area of the other electrode region and B is the area of the other electrode region.

  In such an electronic component package, when the groove is formed at a position far from the center of the mounting electrode package, the mounting electrodes formed at the four corners of the bottom surface of the insulating substrate and the land electrodes of the circuit board are connected by solder. Since the stress applied to the connection portion can be relieved, the occurrence of cracks in the solder can be suppressed.

[Application Example 6]
The electronic component package according to any one of application examples 1 to 5, wherein a concave portion is formed at a position corresponding to the groove portion of the insulating substrate.

  In such an electronic component package, by forming recesses at positions corresponding to the groove portions of the insulating substrate, the mounting substrate and the circuit substrate in the groove portion when the mounting electrodes and the land electrodes of the circuit substrate are connected by soldering. By suppressing the degree of adhesion, it is possible to relieve the stress applied to the connecting portion, so that the occurrence of cracks in the solder can be suppressed.

[Application Example 7]
A surface-mount type electronic device configured using the electronic component package according to any one of Application Examples 1 to 6 is characterized.

  In such a surface-mount type electronic device, when the mounting electrode and the land electrode of the circuit board are connected by solder, the stress applied to the connecting portion can be relieved, so that the occurrence of cracks in the solder can be suppressed. .

Embodiments of an electronic component package of the present invention and a surface mount electronic device using the same will be described below.
In the present embodiment, a surface-mounted crystal resonator (hereinafter simply referred to as a crystal resonator) will be described as an example of the surface-mount electronic device.
1A and 1B are diagrams showing a configuration of a crystal resonator according to a first embodiment of the present invention, where FIG. 1A is a front view and FIG. 1B is a bottom view.
A crystal resonator 1 shown in FIG. 1 accommodates a crystal resonator element 10 having an excitation electrode in an upper surface recess 3 of an electronic component package (hereinafter simply referred to as a “package”) and a recess of the package 2. 3 is sealed with a metal lid 11.
The package 2 includes an insulating substrate 4 having a substantially rectangular bottom shape and a mounting electrode 5 formed on the bottom surface of the insulating substrate 4.
The insulating substrate 4 forming the package 2 is formed by laminating sheet-like insulating materials such as ceramic sheets. Inside the recess 3 are provided two internal pads 6 that are electrically connected to the crystal resonator element 10.
As shown in FIG. 1B, mounting electrodes 5 and 5 are formed on the substantially rectangular bottom surface of the insulating substrate 4 along two opposing bottom sides 2a and 2b, respectively. The mounting electrode 5 is a metal film having a thickness of, for example, about 20 to 30 μm.
The mounting electrode 5 is connected to a conductor film (not shown) in the castellation 20 formed at the approximate center of the bases 2a and 2b. These mounting electrodes 5 are electrically connected to the respective internal pads 6 in the corresponding recesses 3.
In the present embodiment, the groove 7 where the insulating substrate 4 is exposed is formed on the mounting electrode 5 formed on the bottom surface of the package 2.
When the crystal resonator 1 according to the first embodiment configured as described above is surface-mounted on the circuit board (printed circuit board) 15 on the set (device) side, the crystal oscillator 1 is formed on the land electrode 16 of the circuit board 15. The mounting electrodes 5 are connected by solder 17 after corresponding in a one-to-one relationship.

2A and 2B are enlarged views of a connection portion between the crystal resonator 1 and the circuit board 15 of the present embodiment, and FIG. 2C is a connection portion between the conventional crystal resonator and the circuit board 15. It is an enlarged view.
When the conventional crystal unit 100 shown in FIG. 2C is surface-mounted on the circuit board 15, the temperature changes due to a heat cycle or the like due to the difference in thermal expansion coefficient between the package 101 and the circuit board 15. In this case, stress is applied to the entire surface of the mounting electrode 102. In particular, the stress strain was maximum at the end of the mounting electrode farther from the center of the package 101.
On the other hand, as shown in FIG. 2A, when the crystal resonator 1 of the present embodiment is surface-mounted on the circuit board 15, due to the difference in thermal expansion coefficient between the package 2 and the circuit board 15, As in the prior art, when a temperature change occurs, stress is applied to the entire surface of the mounting electrode 5, but the mounting electrode 5 is provided with the groove 7 where the insulating substrate 4 of the package 2 is exposed, so that mounting is performed by the groove 7. It was found that the stress applied to the electrode 5 was separated, and the stress applied to the end of the mounting electrode 5 could be relaxed. This is because the mounting electrode 5 is formed with a groove 7 where the insulating substrate 4 of the package 2 is exposed, that is, a region where the adhesive force with the solder 17 is weak, and is formed outside the groove 7 when stress is applied. This is because the stress applied to the end portion of the mounting electrode 5 is suppressed by elastic deformation of the mounting electrode 5.
Further, as shown in FIG. 2B, when the recess 4a is formed in the insulating substrate 4 corresponding to the groove 7 formed in the mounting electrode 5, the adhesion force of the solder 17 in the groove 7 can be weakened.

Further, as shown in FIG. 3, the groove 7 formed in the mounting electrode 5 in the crystal unit 1 shown in FIG. 1 is formed on the insulating substrate 4 that constitutes the package 2 formed so that the mounting electrodes 5 and 5 are respectively formed. The mounting electrode 5, 5 is divided into two electrode regions 5 a, 5 b by a straight line X parallel to the two opposite bottom sides 2 a, 2 b and passing through the center of the mounting electrode 5, and is located on the center side of the package 2 The groove 7 is formed at a position where A> B, where A is the area of the region 5a and B is the area of the electrode region 5b. That is, the groove portion 7 is formed on the end portion side of the package 2 from the straight line X passing through the center of the mounting electrode 5.
When the groove portion 7 is formed on the end portion side of the package 2 from the center of the mounting electrode 5 in this way, the end portion side where the greatest stress is applied when the mounting electrode 5 and the land electrode 16 of the circuit board 15 are connected by the solder 17. Therefore, it is possible to more reliably suppress the occurrence of cracks in the solder 17.

FIG. 4 is a bottom view of the crystal resonator according to the second embodiment of the present invention. Since the front view is the same as FIG. Moreover, the same code | symbol is attached | subjected to the same site | part and description is abbreviate | omitted.
In the crystal unit 1 shown in FIG. 4, mounting electrodes 5 are provided at the four corners of the substantially rectangular bottom surface of the package 2, and two internal pads 6 electrically connected to the crystal resonator element 10 are provided inside the recess 3. Each internal pad 6 is electrically connected to the corresponding mounting electrode 5. The other two mounting electrodes 5 that are not electrically connected to the electrode on the crystal resonator element 10 are, for example, ground electrodes. A castellation 20 is formed at each corner of the package 2, and each mounting electrode 5 is connected to a conductor film (not shown) in the castellation 20.
In the second embodiment, groove portions 7 where the insulating substrate 4 of the package 2 is exposed are formed on the mounting electrodes 5 formed at the four corners of the bottom surface of the package 2.
When the crystal resonator 1 according to the second embodiment configured as described above is surface-mounted on the circuit board 15 on the set (device) side, the land of the circuit board 15 is the same as in the first embodiment. The mounting electrodes 5 are made to correspond to the electrodes 16 in a one-to-one relationship and then connected by solder 17.
Even when the crystal resonator 1 configured as described above is mounted on the circuit board 15, the temperature of the mounting electrode 5 is changed over the entire surface of the mounting electrode 5 when the temperature changes due to the difference in thermal expansion coefficient between the package 2 and the circuit board 15. Although a stress is applied to the mounting electrode 5, the groove 7 where the insulating substrate 4 of the package 2 is exposed is provided in the mounting electrode 5, and a portion having low adhesion to the solder 17 is formed, so that the groove 7 applies the mounting electrode 5 to the mounting electrode 5. It was found that the stress applied to the end of the mounting electrode 5 can be relaxed by separating the stress.

Further, as shown in FIG. 5, two groove portions 7 formed in the mounting electrode 5 shown in FIG. 4 are located on the edge side of the insulating substrate 4 constituting the package 2 out of the four apexes of each mounting electrode 5. Each mounting electrode 5 is divided into two electrode regions 5a and 5b by a diagonal line Y connecting the vertices, and the area of one electrode region 5a located on the center side of the package 2 is A, and the area of the other electrode region 5b is When B, the groove 7 is formed at a position where A> B.
When the groove portion 7 is formed on the end portion side of the package 2 from the center of the mounting electrode 5 in this way, the end portion side where the greatest stress is applied when the mounting electrode 5 and the land electrode 16 of the circuit board 15 are connected by the solder 17. Therefore, it is possible to more reliably suppress the occurrence of cracks in the solder 17.

Further, when comparing the crystal resonator 1 of this embodiment and the patent document, since the package shape of the patent document 1 is circular, a dead space (useless space) is likely to occur when mounted on a circuit board. On the other hand, the crystal resonator of the present embodiment is preferable from the viewpoint of high-density mounting because the package 2 has a substantially rectangular shape, so that dead space is unlikely to occur.
In addition, when the conductor is formed in a mesh shape or a stripe shape as in Patent Document 2, since the connection area is greatly reduced, the connection strength may be weakened more than the stress relaxation effect of preventing solder cracks. On the other hand, since the crystal resonator 1 of the present embodiment only needs to form at least one groove portion 7, the connection area is not greatly reduced. Therefore, stress relaxation can be achieved without reducing the connection strength. it can.
Further, when the side conductive film and the bottom terminal pad are separated as in Patent Document 3, there is a risk that the side conductive film may not be soldered. On the other hand, the crystal resonator 1 of the present embodiment does not need to separate the mounting electrode on the bottom surface and the conductive film on the side surface, so that there is no fear that the side conductive film will not be soldered.

  FIGS. 6A and 6B are package bottom views of the crystal resonator according to the third embodiment, FIG. 6A is a package bottom view including two mounting electrodes, and FIG. 6B is four mounting electrodes. It is a package bottom view provided with. In addition, the same code | symbol is attached | subjected to FIG.1 and FIG.4 and an identical part, and description is abbreviate | omitted. In the package 2 shown in FIGS. 6A and 6B, the groove 7 formed in each mounting electrode 5 is formed in an arc shape according to the stress distribution. In the case of such a configuration, the stress applied to the end portion of the mounting electrode 5 can be further relaxed.

FIGS. 7A and 7B are package bottom views of the crystal resonator according to the fourth embodiment, FIG. 7A is a package bottom view including two mounting electrodes, and FIG. 7B is four mounting electrodes. It is a package bottom view provided with. In the package 2 shown in FIGS. 7A and 7B, each mounting electrode 5 is provided with a plurality of groove portions 7 formed in an arc shape according to the stress distribution. Also when comprised in this way, it turned out that the stress concerning the edge part of the mounting electrode 5 can be relieve | moderated more.
FIG. 8 is a bottom view of the package of the crystal resonator according to the fifth embodiment. In the package 2 shown in FIG. 8, the mounting electrodes 5 are arranged on both sides of the mounting electrodes 5 as shown in FIG. In this case, the stress applied to the end portion of the mounting electrode 5 can be relieved.

  In the present embodiment, the flat plate metal lid 11 is bonded to the upper surface of the package 2 having the recess 3 to hermetically seal the crystal resonator element 10, but the structure of the package 2 is merely an example. For example, an element mounting pad 6 is provided on the upper surface of a flat package substrate (insulating substrate), a piezoelectric vibrating element 10 is mounted on the element mounting pad 6, and an inverted saddle-shaped (reverse concave) metal lid is bonded. Thus, the present invention can also be applied to an airtight seal.

  In the present embodiment, a crystal resonator is described as an example of the surface-mount type electronic device. However, this is merely an example, and a SAW resonator is mounted on the electronic component package of the present invention. Various piezoelectric devices, or various electronic devices configured by mounting semiconductor elements may be used.

It is the figure which showed the structure of the surface mount-type crystal resonator based on the 1st Embodiment of this invention. It is a principal part enlarged side view at the time of mounting a package on a circuit board. It is explanatory drawing of the groove part formed in the mounting electrode of the crystal oscillator shown in FIG. It is a bottom view of the crystal resonator which concerns on 2nd Embodiment. FIG. 5 is an explanatory diagram of a groove formed in a mounting electrode of the crystal unit shown in FIG. 4. It is a bottom view of the crystal resonator which concerns on 3rd Embodiment. It is a bottom view of the crystal oscillator concerning a 4th embodiment. FIG. 10 is a bottom view of a crystal resonator according to a fifth embodiment. It is a bottom view of a conventional surface-mount type crystal resonator. It is a principal part enlarged view which shows the state which carried out the solder connection of the conventional surface mount-type crystal oscillator on the circuit board.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Quartz crystal resonator, 2 ... Package, 2a, 2b ... Bottom, 3 ... Recess, 4 ... Insulating substrate, 4a ... Recessed part, 5 ... Mounting electrode, 5a, 5b ... Electrode area, 6 ... Internal pad, 7 ... Groove part DESCRIPTION OF SYMBOLS 10 ... Crystal oscillation element, 11 ... Metal lid, 15 ... Circuit board, 16 ... Land electrode, 17 ... Solder, 20 ... Castellation

Claims (7)

An electronic component package comprising an insulating substrate having a substantially rectangular bottom shape and a mounting electrode formed on the bottom surface of the insulating substrate,
A package for an electronic component, wherein a groove portion where the insulating substrate is exposed is formed at a required position of the mounting electrode.   The electronic component package according to claim 1, wherein the mounting electrode is formed along two opposing bottom sides of the insulating substrate.   The electronic component package according to claim 1, wherein the mounting electrodes are respectively formed at four corners of the bottom surface of the insulating substrate.   The mounting electrode is divided into two electrode regions by a straight line passing through the center of the mounting electrode and parallel to two opposing bottoms of the insulating substrate formed so that the mounting electrodes are along each other. The groove portion is formed at a position where A> B, where A is the area of one electrode region located on the center side and B is the area of the other electrode region. Package for electronic components as described.   Of the vertices of the mounting electrode, the mounting electrode is divided into two electrode regions by a diagonal line connecting two vertices located on the edge side of the insulating substrate, and one electrode region located on the center side of the insulating substrate 4. The electronic component package according to claim 3, wherein the groove is formed at a position where A> B, where A is the area of the other electrode region and B is the area of the other electrode region.   6. The electronic component package according to claim 1, wherein a recess is formed at a position corresponding to the groove of the insulating substrate.   A surface-mount type electronic device comprising the electronic component package according to any one of claims 1 to 6.

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