JPH11214551A - Device and method for sealing package of electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize, lower and make light a package maintaining the electric characteristic by a method wherein the package is pressed with a metal cap being on a lower side, while solder of a sealing part is heated from a metal cap side. SOLUTION: A metal cap 18 is mounted on an upper flat face of a heater chip 10 located on a lower side, and a ceramic base 15 and the metal cap 18 are both fixed by a positioning jig 12 so that both positions are misaligned. Further, an appropriate load is pressed by the pressing jig 12 from an outer bottom face of the ceramic base 15. Thus, a adhering intensity of a sealing face can sufficiently be secured. In a piezoelectric device 2 set in a sealing device 1, the heater chip 10 is heated by a pulse heat system, so that as solder 20 is instantaneously fused, the ceramic base 15 and the metal cap 18 can instantaneously be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus and a method for sealing a package of an electronic component in which a piezoelectric resonator such as a quartz oscillator is hermetically sealed, and it is difficult to manufacture a small, low-profile and lightweight package. The present invention relates to a device and a method for sealing a package of an electronic component capable of reducing the size, height, and weight of the package while maintaining the same electrical characteristics as before without using seam welding or the like.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable tendency to reduce the size and weight of mobile communication devices typified by mobile phones, and piezoelectric devices used in various devices have become smaller and smaller.
Demands for low profile and light weight have become strict. 2. Description of the Related Art A piezoelectric device (vibrator, filter) as an electronic component used in various electronic devices and communication devices has a configuration in which a piezoelectric resonator such as a crystal resonator is hermetically sealed in a package. As a piezoelectric device of this type, for example, as shown in FIG. Is manufactured by a method of sealing with a sealing material 24 such as solder, glass, or resin. But,
As described above, in the piezoelectric device using the ceramic cap, since conduction of the cap cannot be ensured, there is a problem that the shield characteristics are poor and the height of the cap cannot be reduced. Further, as shown in FIG. 3, a quartz crystal plate 26 is arranged on the inner bottom surface of a box-shaped ceramic base 25 having an open upper surface, and an electrode lead derived from an electrode provided on the quartz crystal plate 26 is connected to the base 25. There is a type that is connected to a penetrating conductor 27. In this type, a piezoelectric device as a product is completed by sealing the opening of the base 25 with a thin metal cap 28. For this reason, there is no problem in terms of shield characteristics. As a method of fixing the metal cap 28 to the opening of the ceramic base 25, a method of seam welding is generally used. In this fixing step, a ring-shaped metal sealing ring 2 conforming to the shape of the opening edge of the base is used.
9 (made of Kovar, SUS) on the sealing ring 29 with the metal cap 28
Work is performed. However, for example, it is technically impossible to seam weld a package having a length and width of less than 3.0 × 3.0 mm. The reason is that the work of bringing the roll serving as an electrode during seam welding into contact with a desired position of the package cannot be stably performed because the package is too small. That is, even with this type of package, it is difficult to reduce the size, height, and weight.

[0003] Japanese Unexamined Patent Publication No. Hei 9-162687 "Surface acoustic wave device" (Matsushita Electric Industrial) discloses a chip carrier (box-shaped ceramic base) on which a surface acoustic wave is mounted.
A structure is disclosed in which a metal lid having high-temperature solder adhered to the entire surface is stacked, and sealed by heating and melting. According to this conventional technique, an inexpensive and highly reliable surface acoustic wave device can be provided. It is described. Specifically, a package in which the opening of the chip carrier is closed with a metal lid via high-temperature solder is placed inside the coil, and pressure is applied from above the metal lid located above. By applying a high-frequency current to the coil at the same time as applying pressure in a nitrogen atmosphere, the high-temperature solder is melted to achieve hermetic sealing. However, in this conventional example, at the time of joining by heating, solder particles are scattered into the package from the high-temperature solder located between the opening edge surface of the chip carrier and the metal lid and adhere to the piezoelectric element, and the piezoelectric element adheres. There is a problem that the reliability of the device is reduced, and there is a problem that the quality of the obtained product, particularly, the frequency characteristic is poor.

[0004]

A problem to be solved by the present invention is to attach a high-temperature solder to the entire surface of a piezoelectric device package in which a box-shaped ceramic base opening is sealed with a metal cap. By stacking the heated metal lid on the opening formed on the upper surface of the chip carrier and heating the solder, the solder particles from the high-temperature solder are scattered in the package and adhere to the piezoelectric element, thereby reducing reliability. An object of the present invention is to provide a sealing device and a sealing method for a package of an electronic component which can reduce the size, height, and weight of the package while maintaining the conventional electrical characteristics by removing the package.

[0005]

According to a first aspect of the present invention, there is provided a box-shaped ceramic base having an open upper surface and a piezoelectric element accommodated in an inner bottom surface, and a close contact with an opening edge of the ceramic base. And a heater chip for mounting a piezoelectric device comprising a metal cap for sealing the ceramic base with the metal cap facing downward, and positioning the piezoelectric device mounted on the heater chip on the heater chip. It has a positioning jig for fixing and a pressing jig for pressing the bottom surface of the piezoelectric device. According to a second aspect of the present invention, in the first aspect, the heater chip includes the ceramic base and the metal cap,
It is characterized by joining and sealing by instantaneously heating and melting solder by a pulse heating method. According to a third aspect of the present invention, there is provided a box-shaped ceramic base having an upper surface opened and a piezoelectric element housed on an inner bottom surface, and a metal cap for sealing the ceramic base in close contact with an opening periphery of the ceramic base. Wherein the piezoelectric element is supported on the inner bottom surface of the ceramic base, and the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting solder by a pulse heating method. I do. The sealing method invention according to claim 4, when the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting solder by a pulse heating method,
It is characterized by heating and melting while applying pressure. According to a fifth aspect of the present invention, in the method for sealing a package of an electronic component according to the first or second aspect, at the time of joining and sealing by the heat melting or at the time of joining and sealing by heating and melting while applying pressure,
The sealing is performed by heating from the metal cap side in a state where the metal cap is arranged in the opening of the ceramic base with the opening facing downward.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a cross-sectional view showing the structure of an apparatus (package sealing apparatus) for manufacturing a piezoelectric device according to the present invention. Inside the sealing apparatus 1, a package of a piezoelectric device 2 is sealed. That is, the sealing device 1 includes a heater chip 10 on which the piezoelectric device 2 is mounted upside down and a positioning jig for positioning and fixing the piezoelectric device 2 mounted on the heater chip 10 on the heater chip 10. The piezoelectric device 2 includes a tool 11 and a pressing jig 12 that is inserted into the apparatus through a hole 11 a locked at the center of the upper surface of the positioning jig 11 and presses the bottom surface (the upper surface in the figure) of the piezoelectric device 2. In the drawings, the inner wall of the positioning jig 11 and the side wall of the piezoelectric device 2 are illustrated as being separated from each other, but they may be in close contact with each other. The piezoelectric device 2 includes a ceramic base 15 having an open upper surface (a lower surface in FIG. 1), and a piezoelectric element mounted on the inner bottom surface (the ceiling surface in FIG. 1) of the ceramic base 15 via a bump or the like 16 by a flip chip method. 17, a metal cap (for example, a clad material) 18 for sealing the upper surface of the opening edge of the ceramic base 15 over the entire circumference, and a ring-shaped metal seal brazed to the upper surface of the opening edge of the ceramic base 15 It has a ring 19 (made of Kovar, SUS) and a solder 20 for connecting the seal ring metal 19 and the cap 18. As the solder 20, for example, lead, tin, or a mixture of lead and tin mixed with a small amount of metal, for example, silver, bismuth, indium, or the like is used.
Use one at 0 ° C or higher. The reason is that when a reflow furnace is used to mount this piezoelectric device 2 on a printed circuit board, the temperature in the reflow furnace is about 240 ° C., and when the melting point of the solder 20 is 240 ° C. or less, the joint is not formed. This is because there is a risk of peeling. The thickness of the solder 20 is, for example, in the range of 5 to 50 μm, preferably 10 to 30 μm.
μm.

[0007] The method of mounting the piezoelectric element 17 in the ceramic package is not limited to the illustrated one, and various mounting methods can be applied. Further, as the piezoelectric element 17, various elements such as a vibrator and a SAW are assumed. In the sealing device 1, a metal cap 18 is placed on the flat upper surface of the heater chip 10 located on the lower side as shown in FIG.
2, the ceramic base 15 and the metal cap 18 are fixed so as not to be displaced from each other, and furthermore, pressure is applied from the outer bottom surface of the ceramic base 15 with a proper load by the pressing jig 12, so that the adhesive strength of the sealing surface is sufficient. Will be secured. In the piezoelectric device 2 set in the sealing device 1 in a state as shown in FIG.
0 is generated by a pulse heating method, so that the solder 2
Since 0 is instantaneously melted, the ceramic base 15 and the metal cap 18 can be instantaneously fixed.
That is, the pulse heating method is a heating method that uses Joule heat generated when a large pulse current is applied to a high-resistance material such as molybdenum or titanium. Here, a high-resistance material is used as the heater chip 10. In this case, the solder 20 is melted by applying a large pulse-like current to fix the solder. For example, by the sealing operation by the pulse heating method using the sealing device, the vertical and horizontal size is 2.5 × 2.0
When sealing a package of mm size,
Since one cycle of temperature reduction can be completed within 4 seconds, the thermal effect on the piezoelectric element 17 housed in the package is minimized, and a highly reliable piezoelectric device can be manufactured.

Further, when heating is performed by the sealing device 1, the piezoelectric device is turned upside down.
Are located below the piezoelectric element 17, so that even if the particles of the solder 20 are scattered, they do not adhere to the piezoelectric element 17, and the characteristics of the piezoelectric device, especially the frequency characteristics, do not deteriorate. Further, the sealing method of the present invention, which is performed using the sealing device having the above-described configuration, is such that a metal cap is brought into close contact with the edge of the opening of the ceramic base that houses the piezoelectric element on the inner bottom surface via solder. At the time of sealing, the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting the solder by a pulse heating method. Therefore, an efficient production system can be constructed without adversely affecting the internal piezoelectric elements by heat. Further, when the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting solder by a pulse heating method,
Since the heating and melting are performed while applying pressure, the time required for sealing can be further reduced. Further, at the time of joining and sealing by heating and melting using the above sealing device, or at the time of joining and sealing by heating and melting while applying pressure, sealing is performed with a metal cap placed in the opening of the ceramic base with the opening facing downward. Since the stopping is performed, the piezoelectric element is located above the position of the solder, and it is possible to effectively prevent adhesion of the solder particles to the piezoelectric element due to scattering. In the above-described embodiment, the description has been made mainly on the piezoelectric device. However, the present invention is also applicable to a sealing device and a sealing method for a package of an electronic component other than the piezoelectric device.

[0009]

As described above, according to the present invention, in a process of sealing a package of an electronic component in which an opening of a box-shaped ceramic base whose upper surface is opened is sealed with a metal cap, the metal cap is closed. Since the solder of the sealing part was heated from the metal cap side while pressing the package on the lower side, the solder was melted with the metal cap in contact with the opening edge surface of the ceramic base via solder When performing the joint sealing, it is possible to effectively prevent the solder particles from scattering and adhering to the piezoelectric element. That is, conventionally, a metal cap was arranged so as to seal the upper opening of the ceramic base, and the solder of the sealing portion was heated in this state, so that the quartz plate located below the sealing portion was heated. Since the solder in the sealing portion was sometimes scattered, there was a problem with this sealing method, which was an obstacle to the reduction in the height of the package. Since there is no such a problem because it is located below the quartz crystal plate, it is possible to reduce the size, height and weight of the package while maintaining the conventional electrical characteristics, and seal the package of the piezoelectric device. An apparatus and a sealing method can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a sealing device and a sealing method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a conventional package structure of a piezoelectric device.

FIG. 3 is a cross-sectional view for explaining another example of a conventional package structure of a piezoelectric device.

[Explanation of symbols]

Reference Signs List 1 sealing device, 2 piezoelectric device, 10 heater chip, 11 positioning jig, 11a hole, 12 pressing jig, 15 ceramic base, 16 bump, 17 piezoelectric element, 18 metal cap, 19 solder.

Claims (5)

[Claims] 1. An electronic component comprising: a box-shaped ceramic base having an open upper surface and accommodating an electronic component element on an inner bottom surface; and a metal cap for sealing the ceramic base by closely adhering to an opening periphery of the ceramic base. A heater chip mounted with the metal cap facing down, a positioning jig for positioning and fixing the electronic components mounted on the heater chip on the heater chip, and a pressing jig for pressing the bottom surface of the piezoelectric device. And a package sealing device for an electronic component. 2. The electronic component according to claim 1, wherein the heater chip seals the ceramic base and the metal cap by instantaneously heating and melting solder by a pulse heating method. Package sealing device. 3. An electronic device comprising: a box-shaped ceramic base having an open upper surface and containing an electronic component element on an inner bottom surface; and a metal cap for sealing the ceramic base in close contact with an opening edge of the ceramic base. A component element supported on the inner bottom surface of the ceramic base, wherein the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting solder by a pulse heating method. Package sealing method. 4. The method according to claim 3, wherein, when the ceramic base and the metal cap are joined and sealed by instantaneously heating and melting the solder by a pulse heating method, the ceramic base and the metal cap are heated and melted while applying pressure. Electronic component package sealing method. 5. The method for sealing a package of an electronic component according to claim 1, wherein the opening is directed downward at the time of the bonding and sealing by heat melting or at the time of bonding and sealing by heating and melting while applying pressure. A method for sealing a package of an electronic component, wherein sealing is performed by heating from a metal cap side in a state where a metal cap is arranged in the opening of the ceramic base.