JP2000174579A - Manufacture of surface acoustic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a surface acoustic wave device with which a proper amount of sealing material is adhered easily and stably. SOLUTION: A seal ring 6 made of a rectangular frame-shaped metallic film is formed to an upper face outer circumferential part being an joint part of a base member 1 to a cap member, and an Au-Sn alloy wire being a sealing material 7 is sealed over the entire circumference of the seal ring 6 through wire bonding. The bonding between the base member 1 and the cap member is conducted by overlapping the cap member onto the base member 1 and heating them while pressing the cap member onto the base member 1 to melt the Au-Sn alloy wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a surface acoustic wave device in which a surface acoustic wave element is sealed in a package in which a base member and a cap member are joined with a sealing material.

[0002]

2. Description of the Related Art When a surface acoustic wave element is hermetically sealed in a package consisting of a base member and a cap member, a sealing material such as solder or an Au--Sn alloy is previously attached to a joint of one of the members. A method is employed in which the sealing material is heated and melted to join the base member and the cap member. Conventionally, as a method of preforming this sealing material, a foil-shaped sealing material is attached to a cap base metal by cold rolling or the like, or a foil-shaped sealing material punched into a predetermined shape is reflowed at a joint. There are known methods of heating and attaching, printing a paste-like sealing material on a joint portion, applying reflow heating and attaching, and brazing Kovar to a sealing portion and performing Au plating treatment.

[0003]

However, in the above case, there is a portion which is not used as a sealing material, and the sealing material is wasted accordingly. In the case, Kovar is expensive and the material cost of the sealing material is low. There was a problem of getting high. Further, in each of the above cases, there is a problem that a large number of man-hours are required for the pre-forming of the sealing material, and equipment for pre-forming the sealing material is separately required, resulting in an increase in manufacturing cost. Was.

Accordingly, an object of the present invention is to provide a simple and stable attachment of an appropriate amount of a sealing material, thereby reducing material cost and processing time, and achieving high reliability. It is an object of the present invention to provide a method for manufacturing a surface acoustic wave device capable of obtaining a joint.

[0005]

According to one aspect of the present invention, a surface acoustic wave device is sealed in a package formed by joining a base member and a cap member with a sealing material. In the method of manufacturing a surface acoustic wave device according to the present invention, a linear sealing material is adhered to a joining portion of the base member or the cap member by wire bonding, and the sealing material is melted to join the base member and the cap member. It is characterized by doing.

According to a second aspect of the present invention, in the method of manufacturing a surface acoustic wave device according to the first aspect, a seal ring of a metal film is formed at the joint, and the sealing material is wire-bonded to the seal ring. It is characterized by being attached by.

In the above-described manufacturing method, a linear sealing material is attached to the joint between the base member and the cap member by wire bonding, and all the sealing materials can be effectively used. Does not occur, and the material cost of the sealing material can be reduced.

Further, since the encapsulant is attached and fixed by a simple method called wire bonding, the number of steps for forming the encapsulant can be greatly reduced as compared with the above-mentioned conventional method.

Further, the wire bonder device is used in the manufacturing process of the surface acoustic wave device, and it is not necessary to introduce a new facility.

Further, the supply amount of the sealing material can be adjusted by changing the wire diameter of the sealing material or changing the number of the sealing materials to be bonded. The sealing material can be easily attached. That is, it is possible to prevent a decrease in bonding strength and a decrease in airtightness due to a shortage of the sealing material, and it is possible to prevent a short circuit or the like due to an excessive amount of the sealing material.

Further, by forming a seal ring of a metal film at the joint portion and wire-bonding the sealant to the seal ring, wire bonding of the sealant can be performed more reliably. This seal ring serves to improve the flow of the molten sealing material at the time of joining and to suppress the flow to parts other than the seal ring. In other words, by forming the seal ring, wire bonding of the sealing material can be reliably performed, and stable bonding with higher airtightness can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a surface acoustic wave device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a state before the cap member of the surface acoustic wave device is joined, FIG. 2 is a plan view showing a state before the cap member is joined, and FIG. 3 is a sectional view of the surface acoustic wave device.
The surface acoustic wave device of the present embodiment has a structure in which a surface acoustic wave element 2 is sealed in a package in which a concave base member 1 made of ceramic such as alumina and a plate-shaped metal cap member 3 are joined. The surface acoustic wave element 2 is fixed to the upper surface in the concave portion of the base member 1 with an adhesive (die bonding agent), and is connected to a predetermined electrode of the base member 1 by wire bonding a lead wire 5. The base member 1 and the cap member 3 are joined by a sealing material 7 (Au-Sn alloy in this embodiment), and the surface acoustic wave element 2 is hermetically sealed.

The base member 1 is formed in a concave shape by laminating a plurality of ceramic plates, and electrodes for input / output, ground, and the like are formed on the lower surface, the inner surface of the concave portion, and the inside. A seal ring 6 made of a rectangular frame-shaped metal film is provided on the outer periphery of the upper surface of the base member 1 which is to be joined to the cap member 3.
Is formed, and an Au—Sn alloy wire as a sealing material 7 is attached over the entire circumference of the seal ring 6 by wire bonding. In FIGS. 1 and 2, a bonding portion is indicated by reference numeral A. The cap member 3 is a metal plate made of an Fe—Ni alloy or the like, and is plated as necessary.

The joining of the base member and the cap member of this surface acoustic wave device is performed as follows. First, an Au—Sn alloy wire serving as a sealing material 7 is attached onto the seal ring 6 by wire bonding. Next, the cap member 3 is superimposed on the base member 1, and in a state where the cap member 3 is pressed against the base member 1, the base member 1 and the cap member 3 are joined by heating to melt the Au—Sn alloy wire. .

As the wire bonder device for bonding the linear sealing member 7, a device for connecting the surface acoustic wave element 2 to the electrode of the base member 1 is used. As the heating method,
The whole heating by the high temperature furnace or the partial heating by the high frequency is adopted.

The sealing material is not limited to the Au-Sn alloy wire, and a wire such as a solder wire or another metal alloy wire may be used. When a solder wire is used, joining is performed by reflow soldering.

As described above, in the method of manufacturing a surface acoustic wave device according to the present embodiment, a wire is used for joining the base member and the cap member, and the wire is attached by wire bonding. We use effectively.
Moreover, it is not necessary to use an expensive material such as Kovar as the sealing material. That is, since no wasteful portion of the sealing material is generated and an inexpensive material can be used,
The material cost of the sealing material can be reduced.

Further, since a simple method called wire bonding is used and a wire bonder used in another step is used together, the manufacturing cost of the preliminary formation of the sealing material can be reduced.

The seal ring 6 is formed so that the sealing material 7 can be easily wire-bonded. For example, W is formed by printing or the like, and Ni / Au plating is performed thereon. The seal ring 6 has a function of improving the flow of the sealing material at the time of joining and also suppressing the flow of the seal material to parts other than the seal ring 6.

In this embodiment, the linear sealing material is wire-bonded at the four corners of the base member indicated by the symbol A. However, the present invention is not limited to this. Bonding is also performed at the center of each side. The distance between the bonding portions may be set so that the linear sealing material can be more stably attached.

Further, the number of sealing materials need not be one. The number of sealing materials or the wire diameter of the sealing material is set so as to be an appropriate amount of the bonding condition.

The sealing material attached by wire bonding has a curved shape. However, in order to prevent the sealing material from protruding from the seal ring at the time of joining, the height of the sealing material is set such that one sealing line is used. In this case, the width of the seal ring is set to be equal to or less than １ ／ of the width of the seal ring.

In this embodiment, the sealant is wire-bonded to the joint of the base member. However, the sealant may be wire-bonded to the joint of the metal cap member. Further, the cap member is not limited to metal, but may be an insulating material such as a ceramic material such as alumina. In this case, a conductive film is formed on the surface of the insulating material, or the seal ring is formed at the joint. Further, a metal base member may be used.

FIG. 4 is a sectional view showing the structure of a surface acoustic wave device according to a second embodiment of the present invention. This surface acoustic wave device uses a single-layer flat base substrate made of a ceramic such as alumina as a base member 1 and a cap member 1.
A metal cap having a concave shape is used. Also,
A solder wire is used as the sealing material 7, and the solder wire is attached to a metal film seal ring (not shown) formed on the peripheral portion of the base member 1 by wire bonding, and the solder wire is subjected to a reflow soldering method. The base member 1 and the cap member 3 are joined together to seal the surface acoustic wave element 2.

FIG. 5 is a sectional view showing the structure of a surface acoustic wave device according to a third embodiment of the present invention. In this surface acoustic wave device, both the base member 1 and the cap member 1 have a concave shape. This surface acoustic wave device also uses a wire as the sealing material 7, attaches the sealing material to one of the joining surfaces by wire bonding, and heats and melts the linear sealing material to form the base member 1 and the cap. The member 3 is joined.

As in the above embodiments, the shapes of the base member and the cap member are not limited to specific shapes. Further, the fixing of the surface acoustic wave element to the base member or the electrical connection between the surface acoustic wave element and the electrode of the base member are not limited to the above embodiment. For example, the surface acoustic wave element may be soldered to the base member. Alternatively, it may be configured to perform fixing and electrical connection.

[0027]

As described above, according to the method for manufacturing a surface acoustic wave device according to the present invention, a linear sealing material is adhered to the joint between the base member and the cap member by wire bonding. In addition, it is possible to eliminate waste of the sealing material, reduce the number of steps for preforming the sealing material, and significantly reduce material costs and manufacturing costs.

Also, by changing the wire diameter of the sealing material or the number of the sealing materials, it is possible to easily attach an appropriate amount of the sealing material under appropriate bonding conditions, and obtain a highly reliable bonding. Can be.

Therefore, according to the production method of the present invention,
An inexpensive and highly reliable surface acoustic wave device can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state before a cap member of a surface acoustic wave device according to a first embodiment is joined.

FIG. 2 is a plan view showing a state before joining a cap member of the surface acoustic wave device according to the first embodiment.

FIG. 3 is a cross-sectional view of the surface acoustic wave device according to the first embodiment.

FIG. 4 is a sectional view of a surface acoustic wave device according to a second embodiment.

FIG. 5 is a sectional view of a surface acoustic wave device according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base member 2 Surface acoustic wave element 3 Cap member 5 Lead wire 6 Seal ring 7 Sealing material

Claims (2)

[Claims] 1. A method of manufacturing a surface acoustic wave device in which a surface acoustic wave element is sealed in a package formed by joining a base member and a cap member with a sealing material. A method for manufacturing a surface acoustic wave device, comprising: attaching a linear sealing material to the base member by wire bonding; melting the sealing material; and joining the base member and the cap member. 2. The method for manufacturing a surface acoustic wave device according to claim 1, wherein a seal ring of a metal film is formed at the joint, and the sealant is attached to the seal ring by wire bonding. Of manufacturing a surface acoustic wave device.