JPH02179018A - Surface mount type surface acoustic wave device - Google Patents

Abstract

PURPOSE:To provide an electromagnetic shield performance to a surface acoustic wave device and to improve the S/N by forming a lower conductor layer to an upper face provided with an external electrode, providing a ground electrode in continuity with the lower conductor to an outer circumferential face of the base and connecting an upper conductor layer to the ground electrode with a connection electrode provided to a frame. CONSTITUTION:A package 13 containing a surface acoustic wave element 4 consists of a base 3, a frame 5 and a cover 6, and the base 3 forms a lower conductor layer 7 with a comparatively wider area to a middle part of the upper face of a base board 11 such as an epoxy laminated plate. Moreover, a ground electrode 8 is formed to a semi-circular notch 12 provided in the middle of both side faces of the board 11 and the lower conductor layer 7 and the electrode 8 are connected by a connection wiring pattern 14. Furthermore, a couple of input external electrodes 1 and a couple of output external electrodes 2 are formed to semi-circular notches 15, 16 provided to both ends of both side faces of the board 11 and an element connection pad 17 is prolonged to the upper side of the board 11 from electrodes 1, 2 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface-mounted surface-wave device in which a surface-wave element utilizing surface acoustic waves is housed in a package.

[Background technology]

A package similar to the one used in the present invention is a chip carrier 37 having a structure as shown in FIG. 4, which is used for packaging LSIs and the like. This is done by forming a bonding pad 32 and a tap 33 by plating or the like on the upper and outer circumferential surfaces of a base 31 made of an epoxy laminate, respectively, and forming a die attachment part 33 in the center.
After bonding wiring between the LSI chip (not shown) mounted on 4 and the bonding pad 32, the LSI
A frame 35 is stacked on top of the base 31 so as to surround the chip, and 1236 is further placed on the top surface of the frame 35, and the base 31, frame 35, and diamond 36 are pasted together with adhesive or the like to seal the LSI chip inside the chip carrier 37. It is.

However, such chip carriers are for hermetically sealing LSI chips, and until now there has been no chip carrier with an electromagnetic shielding function.

In addition, in conventional surface-mounted surface wave devices, as disclosed in Utility Model Application Publication No. 60-47321 (not shown), a lid with a recess on the bottom surface is attached to the surface of the surface wave element. There was no package with electromagnetic shielding performance, as the circuit of the surface wave element was simply sealed by direct adhesion.

For this reason, conventional surface wave devices have a problem in that noise in the output signal increases due to external electromagnetic noise.

[Problem to be solved by the invention] However, the present invention has been made in view of the above-mentioned background technology, and its purpose is to provide electromagnetic shielding performance to a surface mount type package in which a surface wave element is incorporated. 6.1 Means for Solving the Problems] For this reason, the surface-mounted surface wave device of the present invention has a surface wave element mounted on a base provided with an external electrode, and a surface wave element mounted on the upper surface of the base so as to surround the surface wave element. In a surface wave device in which a frame is placed and a lid is placed on the top surface of the frame to seal the surface wave element, a chain layer is formed on two sides of the base, and conduction is established with the P' conductor layer on the outer peripheral surface of the base. A ground electrode is provided, an L conductor layer is formed on the lower surface of the wire, and the double layer is electrically connected to the ground electrode by a connecting electrode provided on the frame. .

[Effect]

In the present invention, since the surface wave element is sandwiched between the child chain layer provided in the - direction of the base and the one conductor layer provided on the lower surface of the lid, the surface wave element is It can be shielded from external electromagnetic noise, and the S/N ratio can be improved without picking up external noise. However, the -1- of the tube is connected by the connection electrode provided on the frame.
Since the conductor layer is electrically connected to the earth electrode, the conductor layer can be easily connected to the earth electrode simply by assembling the package by sandwiching the frame between the lid and the base.

Furthermore, when mounting on a board, the upper and lower conductor layers can be grounded by simply connecting the ground electrode to the ground line, making the mounting work easy.

〔Example" Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the package 13 that houses the surface wave element 4 has a base 3, a frame 5, and a tube 6, each of which is made of a copper-clad laminate such as an epoxy laminate (in the drawing, the copper foil pattern is marked with diagonal lines). is an alms.).

The base 3 has a relatively wide area N7 formed in the center of the upper surface of the base substrate 1, such as an epoxy laminate, and a semicircular notch 12 provided in the center of both sides of the base substrate 11. A ground electrode 8 is formed, and a child chain layer 7
and the ground electrode 8 are electrically connected by a connection wiring pattern 4. Further, semicircular arc-shaped notches 15 and 16 are provided at both ends of both sides of the base board 11.
A pair of input-side external electrodes 1 and a pair of output-side external electrodes 2 are formed on both cutting edges 1.5 and 1.6, respectively, and each external electrode 1 and 2 is directed toward the upper surface of the base substrate 11. An element connection pad 17 is extended. This base 3 is
It is obtained by separating the base parent board (not shown), and the child connected body I7 of the base 3 is on the upper surface of the base parent board.
A repeating pattern of copper foil corresponding to the connection wiring pattern 4 and the element connection pad 17 is formed, and through holes are formed at the locations corresponding to the ground electrode 8 and the external electrodes 1 and 2. . Thus, a plurality of bases 3 can be obtained by separating the base substrate so as to divide the through hole into two, and each through pole plating becomes the ground electrode 8 and the external poles 1 and 2.

The frame 5 is a rectangular frame substrate [8] with arc-shaped notches 19 provided at the center of both sides thereof, and connection electrodes 10 formed in the notches [9]. The outer dimensions of the frame 5 are equal to the outer dimensions of the base 3, and the connection electrode 10 is attached to the frame 5.
When placed on top of the base 3, the ground electrode 8 of the base 3
are arranged to match. In addition, the frame 5, whose inner dimensions and thickness are determined so that the surface wave element 4 can be housed therein, is also obtained by cutting off the crushed grain substrate (not shown). Frame holes are opened in the grain substrate at predetermined pitches, and through holes are provided at locations corresponding to the connection electrodes 10. By cutting this frame board into predetermined dimensions so as to divide the through holes into two, a plurality of frames 5 can be obtained, and each through hole plating becomes a connecting wire i10.

The lid 6 has a main conductor layer 9 formed by pasting copper foil on the entire lower surface of a lid substrate 20 in the shape of a rectangular plate having the same dimensions as the base substrate 11. This soba 6 is also obtained by cutting into predetermined dimensions a mother board (not shown) of a copper-clad laminate whose entire lower surface is coated with copper foil.

Although the surface wave element 4 is only shown in a simplified manner in FIG. An input side drawer pad 23 and an output side drawer pad 24 are provided.

Next, a method of assembling one surface wave device will be explained.

As shown in FIG.
The comb-shaped electrode 22 is lifted from the chain layer 7 and the comb-shaped electrode 22 is
The respective corresponding drawer pads 23 and 24 and element connection pads 17 and 17 are soldered using reflow solder 25 or the like in a state where they are electrically and mechanically separated from each other. Next, the frame 5 is placed on the base 3, and the lower surface of the frame 5 is adhered to the base 3 with adhesive. As a result, the surface wave element 4 is housed in the frame 5, and the ground electrode 8 of the base 3 and the connection electrode 10 of the frame 5 are electrically contacted at the top and bottom. Thereafter, the top surface of the frame 5 is covered with the lid 6, the connection electrode 10 is brought into electrical contact with the main conductor layer 9, and the lid 6 is adhered to the top surface of the frame 5 with an adhesive. In this way, the surface wave device 4 is hermetically sealed within the package 13 consisting of the base 3, frame 5, and 126, and assembled for surface mounting. That is, this surface mount type surface wave device is temporarily fixed on a wiring board (not shown), and each input/output side external electrode 1, 2 and ground electrode 8 are connected to the land part of the wiring board by reflow soldering or the like. It is soldered. In this way, when the ground electrode 8 is connected to the ground line of the wiring board, the child chain layer 7 is grounded, and the main conductor layer 9 is also grounded via the connection electrode 10, so that the internal surface wave element 4 It is sandwiched between the grounded upper and lower conductor layers 7 and is electromagnetically shielded. Note that the grounding electrode 8, the connecting electrode IO, and the main conductor layer 9 not only obtain electrical continuity through mere contact, but also completely connect the main conductor layer 9 by electrically bridging each other with a solder film. However, this method allows a solder film to be formed between the ground electrode 8, the connection electrode 10, and the lower conductor layer 9 by flow soldering when the surface wave device is mounted on the wiring board without a separate process. You can.

In the above description of the assembly method, the case where the base, frame, and lid are assembled after being separated from the parent board has been described, but the manufacturing process can be simplified by assembling with the parent board as it is. That is, a plurality of surface wave elements are mounted on the upper surface of the base motherboard so as to correspond to the sub-assembly layer, and the frame substrate is stacked on top of the base motherboard so that the surface wave elements are housed in the frame holes. A foster mother substrate is superimposed and adhered on top of this framework substrate, and then the mother substrate assembly is cut to manufacture a plurality of surface wave devices.

As a result, the number of steps such as the adhesive application step and the mother board cutting step can be significantly reduced.

Note that although the above description has been made regarding the case of a four-terminal surface wave filter, the present invention is not limited thereto, and the number of external electrodes and the like will vary depending on the type of surface wave element. In addition, double-sided copper-clad laminates are used for the base and frame to form lands on the upper and lower edges of the ground electrode, connection electrode, etc., increasing the contact area between the ground electrode, connection electrode, and main conductor layer. Alternatively, a copper-clad laminate, such as an epoxy laminate with copper foil attached, was used as the base.
It may also be a ceramic substrate with a vapor-deposited film formed thereon.In addition, in the above embodiment, through-holes are used to
Since the poles are provided, the electrodes are provided in the semicircular notch, but if a through hole is not used, each electrode may be formed without providing the notch.

〔Effect of the invention〕

According to the present invention, since the surface wave device can be provided with electromagnetic shielding performance, the surface wave element can be shielded from external electromagnetic noise, and the surface wave element can be shielded from external electromagnetic noise.
It is possible to prevent the /N ratio from decreasing and sending out erroneous signals. In addition, by simply assembling the package by stacking the base, frame, and lid, the listed body layer can also be electrically connected to the ground, simplifying the assembly process. Furthermore, the upper and lower conductor layers can be grounded simply by fixing the ground electrode to the ground line of the board with solder or the like, making the mounting work easy.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a package according to an embodiment of the present invention, Fig. 2 is a front view showing a surface wave element mounted on the same base, and Fig. 3 is an assembled surface wave device. FIG. 4 is an exploded perspective view showing a conventional package. 1... Input side external electrode 2... Output side external electrode 3
... Base 5 ... Frame 7 ... 1 Conductor layer 9 ... Listed body layer 4 ... Surface wave element 6 ... Diamond 8 ... Earth electrode 10 ... Connection electrode diagram

Claims (1)

[Claims] (1) A surface where the surface wave element is mounted on a base equipped with external electrodes, a frame is placed on the top of the base so as to surround the surface wave element, and a lid is placed on the top of the frame to seal the surface wave element. In the wave device, a lower conductor layer is formed on the upper surface of the base, a ground electrode that is electrically connected to the lower conductor layer is provided on the outer peripheral surface of the base, an upper conductor layer is formed on the lower surface of the lid, and a lower conductor layer is provided on the frame. A surface-mounted surface wave device, characterized in that the upper conductor layer is electrically connected to the ground electrode by a connecting electrode.