JP2002289720A - High frequency device package - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency device package for mounting a high frequency device, and more particularly to an IC package used in a millimeter wave band. The “package” in this specification refers to a component used for convenience when mounting a high-frequency device on another circuit or substrate.

[0002]

2. Description of the Related Art A high-frequency device used in a microwave band or a millimeter wave band has a very high circuit density, so that it is very difficult to connect terminals when mounted on a substrate. Also,
In a high-frequency device, it is necessary to shield more completely than a low-frequency circuit in order to prevent interference of signal components from other circuits. Therefore, it is common to use the high-frequency device housed in a dedicated package (high-frequency device package).

[0003]

In a high-frequency device, an internal signal may be affected by aerial radio waves, and feedback or oscillation between circuits may occur. For this reason, the high-frequency device package is required to have a structure that prevents airwaves from reaching the high-frequency device to be accommodated.
Conventional high-frequency device packages may be configured using parts having complicated shapes in order to obtain necessary characteristics. However, from the viewpoint of suppressing an increase in manufacturing cost, parts having complicated shapes are required. Is preferably not used as much as possible.

[0004] It is a main object of the present invention to provide a high-frequency device package that can reliably suppress external influences on a housed high-frequency device while meeting the above demands.

[0005]

According to the present invention, there is provided a high-frequency device package provided with an insulating wall forming member for forming a concave space in a region for mounting the high-frequency device, and mounted on the wall forming member. An insulating lid for covering the concave space, and an electromagnetic wave absorber for absorbing electromagnetic waves propagating in the space by being placed on the insulating lid, wherein the electromagnetic wave absorber and the insulating lid are provided. And a metal body having a shape and a size capable of covering at least the concave space. The wall forming body and the lid are all made of, for example, a ceramic member. With this structure, the metal body and the radio wave absorber act as equivalent grounds, so that the input and output electromagnetic waves of the mounted high-frequency device can be prevented from being coupled through the lid. In addition, since the metal body and the radio wave absorber act equivalently as ground, the radiation wave of the electromagnetic wave of the high-frequency device is completely reflected, and there is no loss. Therefore, the electromagnetic waves in the concave space are cut off.

[0006] In a preferred embodiment, by using an aluminum foil or a copper foil for the metal body, a high-performance device package can be realized at lower cost and with high performance. Further, the wall surface and the lid inner surface that come into contact with the concave space,
All are made of insulating material. Further, when the high-frequency device is housed in the concave space, the wall forming body is laminated on a ceramic substrate on which a terminal portion that conducts with a predetermined terminal of the high-frequency device is formed. It is also possible to adopt a structure in which at least a part of the terminal portion is exposed without being covered by the wall forming body. The insulating members can be joined together using a resin adhesive.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below using an example of a package for a high-frequency device used in a millimeter wave band. In order to obtain sufficient performance as a high-frequency device package, a substrate for mounting the high-frequency device, a side wall forming a concave space for mounting the high-frequency device on the substrate, and terminals of the high-frequency device projecting from the side wall And a cap for covering a concave space formed by the side wall. Also, if necessary, it is necessary to provide a radio wave absorber that absorbs radio waves propagating in the air by being placed on the cap.

As the side wall, a metal side wall, a ceramic side wall, or a metalized side wall of a ceramic side wall can be considered. First, an example of a high-frequency package using these side walls will be briefly described.

FIG. 1 is an exploded perspective view showing an example of the structure of a package using metal side walls. In this package, a ceramic substrate 22 for holding a terminal portion 27, a ceramic side wall 23 and a metal side wall 24 are arranged on a metal plate 21 serving as a ground. A concave space for accommodating the high-frequency substrate is formed by the metal side wall 24. The ceramic side wall 23 is provided to prevent the conductive pattern on the ceramic substrate 22 from being short-circuited to the metal plate 21 by the metal side wall 24.

[0010] The concave space formed by the metal side wall 24 is a metal cap 25 also called a sealer cap.
For preventing the dielectric effect. Further, an electromagnetic wave absorber 26 is placed on the metal cap 25. When the amplification degree of the mounted high-frequency device is too high, the electromagnetic wave absorber 26 may cause oscillation by the output of the high-frequency signal propagating in the air and returning to the input, or may cause swell in the frequency characteristic. Therefore, it is provided to prevent this. Therefore, when the amplification of the high-frequency device does not become excessively high, the electromagnetic wave absorber 26 becomes unnecessary. Examples of the material of the electromagnetic wave absorber include a rubber mixed with ferrite and an epoxy resin mixed with ferrite.

The package having the structure shown in FIG. 1 can be used at a frequency lower than the frequency at which the size of the concave space surrounded by the metal plate 21, the metal side wall 24, and the metal cap 25 is in the cutoff mode. . In order to realize the cutoff mode, the metal side wall 24 and the metal cap 25 must have a structure that is electrically connected to the metal plate 21 and must not be electrically connected to the terminal 27 on the ceramic substrate 22. For this reason, the metal side wall 24 has a complicated shape in which a portion for taking out the terminal portion from the inside is cut out.

FIG. 2 is an exploded perspective view of a laminated structure in which the ceramic substrate 22 and the ceramic side wall 23 in the package having the structure shown in FIG. 1 are formed by ceramics. With the structure shown, the package does not use the metal side wall 24. Such a structure
Since the structure is simpler than that of FIG. 1, there is an advantage that mass production and reduction of manufacturing cost can be achieved.

The package having the structure shown in FIG. 2 includes a metal plate 31 serving as a ground, a ceramic substrate 32 corresponding to a part of the above-described ceramic side wall 23 and the metal side wall 24, and a ceramic side wall corresponding to a part of the above-described metal side wall 24. 33, a ceramic cap 34 also called a sealer cap or sealer lid, an electromagnetic wave absorber 35 and a terminal 37 which are the same as those described above.

In the package having such a structure, when the high-frequency signal output from the high-frequency device returns from the output side to the input side, it propagates not only in the air, but also because the ceramic cap 34 has a high dielectric constant. The field is concentrated, and the coupling between input and output is larger than that of the package shown in FIG. Therefore, almost without exception, the electromagnetic wave absorber 3
5 is required.

FIG. 3 is an exploded perspective view showing an example of a package obtained by improving the package having the structure shown in FIG. 2 and metallizing a ceramic wall. This package includes a metal plate 41 serving as a ground, a ceramic layer 42 for extracting a control signal and a high-frequency signal from a mounted high-frequency device, and a ceramic side wall 43. The ceramic side wall 43 is metallized only on a part of the inner side surface of the package so as not to short-circuit with the control signal and the high-frequency signal on the ceramic layer 42. Further, this package is provided with a ceramic side wall 44 having at least a metallized inner side surface and an upper surface, a metal cap 45, and an electromagnetic wave added to prevent feedback and oscillation by electromagnetic waves propagating through the air and the metal cap 45. An absorber 46 and a terminal 47 are also provided.

A package having this structure has the same performance as that of the package of FIG. 1, but has a complicated metal part such as the metal side wall 24 of FIG.
There is no divided ceramic substrate such as the ceramic side wall 23 and the ceramic side wall 23, and a simple structure in which plate-like components are overlapped. In other words, the characteristics of this package are close to those of the package having the structure of FIG. 1, and the manufacturing cost is close to the manufacturing cost of the package of FIG.

Each of the packages having the structure shown in FIGS. 1 to 3 has the advantage that required characteristics can be obtained, but there is room for improvement as described below. That is, in the case of the structure shown in FIG. 1, the metal side wall 24 has a complicated shape, which is disadvantageous in cost. In the case of the structure shown in FIG. 2, radiation is radiated from the inside of the package toward the ceramic cap 34. Since the electromagnetic field is also converted into heat by the electromagnetic wave absorber 35, the loss increases as compared with the case where the ceramic cap 34 is not provided.

The structure shown in FIG. 3 is less expensive than the package shown in FIG. 1, but is more expensive than the structure shown in FIG. 2 because a side metallization step is required. In this structure, since the metalized side wall is on a ceramic substrate having a higher dielectric constant than vacuum, the wavelength of the electromagnetic field is shortened by the ceramic. For this reason, the maximum working frequency is lower than that of the structure shown in FIG. Furthermore, since the side wall of this package is a thin film formed by metallization, it not only has a small effect as a shield, but also has the effect of radiating electromagnetic fields due to resonance, and unexpected package resonance occurs. there's a possibility that. Further, the metal cap 45 and the ground 41
The metal cap 4
5 may be an electromagnetic field propagation path.

Therefore, the following is an example of a package having a structure capable of solving the above-mentioned problem while ensuring at least the characteristics as shown in FIGS. FIG. 4 shows an exploded perspective view thereof. In the package having this structure, a metal plate 11 serving as a ground is used as a substrate, and a ceramic substrate 12 provided with a terminal portion 17 and a ceramic side wall 13 are provided on the metal plate 11.
Are attached in this order, and a ceramic cap 14 is provided immediately above the ceramic side wall 13.
An electromagnetic wave absorber 16 is attached to the ceramic cap 14 with a metal foil 15 sandwiched therebetween.
As the metal foil 15, an aluminum foil or a copper foil can be used. In this example, the ceramic cap 14
Is an open area O of a concave space formed by the side wall 13.
(The area corresponding to the area where the high-frequency device is mounted on the metal plate 11) It has a size larger than the opening area 0 so as to cover the entirety and prevent the ceramic cap 14 from falling into the opening area 0. . Metal plate 1
1, the ceramic substrate 12 and the ceramic side wall 13 have the same length in the longitudinal direction, and the ceramic cap 14 has the same length in the longitudinal direction as the length of the metal plate 11 and the like. .

FIG. 5 shows a state in which a high-frequency device is actually mounted on this package to form a package product. FIG.
3A is a plan view of a package product, FIG. 3B is a cross-sectional view, and FIG. 3C is an exploded perspective view. High frequency devices are MMIC (Monolithic Microwave Integrated Circuit)
its) 17 and MIC (Microwave Integrated Circuits)
18, which are bonded on the substrate 11 by wire bonding 19.

The package product shown in FIG. 5 has a ceramic substrate 1 having a metal plate 11 and a terminal 17 formed thereon.
Then, both the MMIC 18a and the MIC 18b, which are high frequency devices, are mounted in a concave space surrounded by the ceramic side wall 13 on the ceramic substrate 12, and then wire bonding 19 is performed. Thereafter, a ceramic cap 14 is adhered and adhered to the ceramic side wall 13, and a metal foil 15 is adhered to the ceramic cap 14.
Finally, the electromagnetic wave absorber 16 is attached to the metal foil 15,
Complete the package product.

As described above, the ceramic cap 14
By attaching the metal foil 15 between the electromagnetic wave absorber 16 and the electromagnetic wave absorber 16, the electromagnetic field in the package can be reduced without using a side wall having a complicated structure as shown in FIG. 2 and metallizing or a metal cap as shown in FIG. Can be kept in a cut-off state. In addition, since a ceramic member is used for the side wall and the cap, bonding with a resin adhesive is possible, and since the entire side wall does not need to be metallized, it can be manufactured at low cost. In addition, the metal foil 15 is bonded to the cap, and the electromagnetic wave absorber 16 is further bonded to the upper surface of the metal foil 15, so that it is an inexpensive package adopting a structure in which a material such as ceramics, which does not conduct electricity, is basically laminated. However, it becomes possible to have the same performance as an expensive metallized package. Furthermore, metal foil 15
Is provided, unlike the case where a thin film formed by metallization is used, unexpected resonance does not occur.

[0023]

As is apparent from the above description, according to the present invention, there is provided a package for a high-frequency device which can be manufactured at low cost while having the effect of reducing the effects of abnormal oscillation and feedback inside the package. Can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of a package using metal side walls.

FIG. 2 is an exploded perspective view showing an example of a package using a ceramic side wall.

FIG. 3 is an exploded perspective view showing an example of a package in which ceramic side walls are metallized.

FIG. 4 is an exploded perspective view showing an example of the structure of a suitable package.

FIG. 5 shows an example of a package product, and (a)
Is a plan view, (b) is a sectional view, and (c) is an exploded perspective view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Metal plate 12 Ceramic substrate 13 Ceramic package side wall 14 Ceramic cap 15 Metal foil 16 Electromagnetic wave absorber 17 Terminal part O Opening area

Claims (6)

[Claims] 1. An insulating wall forming body that forms a concave space in a region for mounting a high-frequency device, an insulating lid that covers the concave space by being placed on the wall forming body,
An electromagnetic wave absorber that is located outside the insulating lid and absorbs electromagnetic waves propagating in the surrounding space, wherein at least the concave space is covered between the electromagnetic wave absorber and the insulating lid. A package for a high-frequency device, comprising a metal body having a shape and a size interposed therebetween. 2. The high frequency device package according to claim 1, wherein the metal body is one of an aluminum foil and a copper foil. 3. The high-frequency device package according to claim 1, wherein all of the wall surface and the inner surface of the lid contacting the concave space are made of an insulating member. 4. The high frequency device package according to claim 1, wherein the wall forming body and the lid are made of a ceramic member. 5. The wall forming body is laminated on a ceramic substrate on which a terminal portion that conducts with a predetermined terminal of the high-frequency device when the high-frequency device is accommodated in the concave space is formed. 5. The high frequency device package according to claim 4, wherein at least a part of the terminal portion of the ceramic substrate is exposed without being covered by the wall forming body. 6. The high-frequency device package according to claim 1, wherein said insulating members are joined to each other using a resin adhesive.