JP2007324364A - Airtight container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a container structure which is not affected by the sealing condition of the container in order to improve the factor which causes frequency fluctuation etc. according to the conditions during hermetic sealing of a piezoelectric vibrator. <P>SOLUTION: The problem in the airtight container which is sealed by a container and a lid is solved so that the joint surface processing of the lid forms a silver layer and a tin layer on the lid material through a joint member, and it joins to the lid by ultrasonic vibration, thereby reducing the unit price being reduced. By the use of ultrasonic sealing, it becomes possible to lower the sealing temperature by stabilizing frequency fluctuation before and after the sealing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a container sealing material for improving a factor that causes a frequency variation or the like depending on conditions at the time of hermetic sealing of a piezoelectric vibrator.

  Ceramic, glass, metal, resin, and the like are used for the package of the small SMD vibrator, and ceramic, metal, and glass with high humidity resistance and airtightness are used for those that require accuracy. Resin packages are used for general consumer products that have relatively high stability due to their hygroscopicity and airtightness.

  As for the lid, metal, ceramic, glass, etc. with good airtightness and moisture resistance are used in the same way as the package. Sealing methods include seam welding of metal lids, gold-tin fusion, glass fusion of ceramic caps, metal Welding of the base and metal cap is used, and electron beams and lasers are also being used and studied.

  Recently, the use of mobile terminals continues to expand, such as IC tags, TV modules, GPS receivers, hard disk (HDD) modules, and the applications continue to increase. In order to satisfy the functions, GPS modules, HDD modules, tuner modules, etc. are installed in terminals. There is a tendency to increase the number of functional parts. On the other hand, since the size of the terminal device itself is limited, there is an increasing demand for reducing the size and height of parts while maintaining accuracy, airtightness, and moisture resistance.

  Strict demands are also made on the unit price of products, and the issue is how to increase the productivity by reducing the investment in material costs. However, in order to achieve ultra-compact and low profile while ensuring accuracy and reliability, it is necessary to reduce the thickness of the bottom surface and the lid. The mainstream of ceramic material packages is that the lid is made of metal, and due to the difference in the thermal expansion coefficient between the ceramic container and the lid, thermal stress is applied during welding and sealing, strain remains, and the package strength is maintained. Therefore, materials and sealing methods are also limited. At present, a small hermetic sealing method with an outer dimension of 2.5 mm × 2.0 mm or less is a gold tin lid heat fusion method or an Ag wax cladding. Welding with lid electron beams is the mainstream.

In recent years, there has also been proposed a method in which vibrators are collectively formed from a quartz wafer by photolithography and collectively sealed by anodic bonding in the wafer state. In addition, a method has been proposed in which glass is used for a base (package) and strip-shaped vibrators are individually mounted and adjusted and then collectively sealed in a wafer state. On the other hand, since the size of the terminal device itself is limited, there is an increasing demand for reducing the size and height of parts while maintaining accuracy, airtightness, and moisture resistance.
JP, 7-96610, A In addition to the prior art document specified by the above-mentioned prior art document information, the applicant has not found prior art documents related to the present invention by the time of filing of the present application. .

  A general piezoelectric vibrator has a configuration in which a vibrating piece in which electrodes for excitation are formed on both surfaces of a flat plate of a piezoelectric material is housed as a piezoelectric vibrating element plate in a container shape having an airtight seal. Therefore, in order to achieve both the sealing accuracy, airtightness, and moisture resistance of the piezoelectric vibrator container, it is common to use inorganic materials such as glass, ceramic, and metal for the package. Further, it is necessary to make the entire container smaller and thinner at the same time by reducing the thickness of the lid.

However, the mainstream of ceramic material packages is that the lid is made of metal, and due to differences in the thermal expansion coefficient of the ceramic container and lid, thermal stress is applied during welding and sealing, and strain remains. There is an upper problem.
As a conventional sealing example, for example, heat fusion using a gold-tin eutectic alloy can suppress the thermal stress on the joint portion of the container to a low level as compared with sealing by welding means, but a gold material ( Since the use of a gold-tin eutectic alloy), the material cost becomes high, and the current situation depends on the market fluctuation of the gold market, which causes the cost fluctuation.

  In addition, in the case of a container welded with a silver wax clad sealing material by an electron beam, a stress at the time of sealing is applied to the container, resulting in a phenomenon that stress strain remains in the joint after sealing. To do. In addition, there is a problem that the frequency fluctuates because the piezoelectric vibrator housed in the container is thermally strained by heating.

  Therefore, in order to solve the above-described problems, the present invention provides an airtight container that is hermetically sealed with a container and a lid, wherein the joint surface treatment of the lid is performed on the lid material by a silver layer and a tin layer via a joint member. And an airtight container joined to the container by ultrasonic vibration.

  In short, the present invention uses a sealing material of a silver layer and a tin layer instead of the conventionally used gold-tin material, and at the time of joining, the container and the lid are applied by applying vibration, heat and pressure by ultrasonic vibration. Are integrated to form a sealed container.

  In the present invention, the conventional gold-tin eutectic alloy sealing material is not conventionally bonded to the container and the lid by a heating method, but is conventionally cited by bonding the silver layer and the tin layer sealing material by ultrasonic waves. The problem is solved by greatly improving the thermal strain and stress strain that are the issues.

  According to the present invention, by forming the silver layer and the tin layer in the sealing material, the lid unit price can be reduced, and by using ultrasonic sealing, the sealing temperature can be lowered, and before and after sealing. Frequency fluctuation is stable. In addition, by using ultrasonic sealing, temporary sealing before main sealing is not necessary, and facilities and manufacturing costs can be reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view focusing on the lid 2 of the present invention. For example, the lid 2 is bonded to the lid 2 in which the silver layer 3 and the tin layer 4 are formed via a bonding member on the side that comes into contact with the container 1 using a metal, ceramic as a base material, that is, at least a portion of the sealing surface that directly contacts the sealing surface. Container.

  A lid 2 in which the silver layer 3 tin layer 4 is treated after passing through titanium, chromium, nickel, which are metal materials used for the base, for example, as a bonding material for bonding the silver layer 3 tin layer 4 to the base material of the container 1 It has become. Then, the container 1 and the lid 2 are joined to each other by joining the lid 2 to the container 1 by ultrasonic vibration so as to eliminate the occurrence of stress distortion due to thermal distortion or stress compared to the conventional case. The influence on the crystal resonator generated by this can be largely eliminated.

  FIG. 2 is a flowchart of a manufacturing process using the lid 2 of the present invention. Although FIG. 2A shows a series of flows, there is no difference from the conventional method as a whole. However, in the present invention, a silver layer 3 tin layer 4 is formed on the joining surface of the lid 2 and the joining means is super A hermetic seal is realized by applying sonic vibration. Conventionally, the sealing process is improved as shown in the present invention in order to eliminate the problems described in the prior art of the process that has been sealed with the gold-tin eutectic alloy. As a result, a configuration as shown in a perspective view of the piezoelectric vibrator as shown in FIG. In this case, the metallized layer formed on the bonding surface on the container 1 side and the silver layer 3 and the tin layer 4 formed on the lid, the tin layer 4 is bonded to the metallized layer to achieve hermetic sealing. To do. In addition, the sealing part of this invention can perform favorable sealing even if the thickness of the silver layer 3 and the tin layer 4 is a one-to-one ratio.

  In addition, about the ultrasonic vibration mentioned above, a sealing process is performed by an oscillation frequency of 20 KHz-50 KHz as an example, 100-500 msec as an application time, and 1-10N as a pressurization amount. Among the above conditions, the best condition is considered that the heating temperature at the sealed portion is around 150 ° C., although no data is published, but it is experimentally favorable.

It is a conceptual diagram explaining the structure of the lid | cover of this invention. It is the flowchart which shows the flow of the manufacturing process of this invention, and the conceptual diagram of a piezoelectric vibrator.

Explanation of symbols

1 container 2 lid 3 silver layer 4 tin layer

Claims (1)

In an airtight container that hermetically seals the container and lid,
An airtight container characterized in that the bonding surface treatment of the lid forms a silver layer and a tin layer on a lid member via a bonding member and is bonded to the container by ultrasonic vibration.

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