JPH0262064A - Ceramic package - Google Patents

Abstract

PURPOSE:To facilitate connection with a high frequency probe for a test by leading out an input-output terminal of a microwave circuit through the use of a coplanar line consisting of a central conductor pattern and an earth conductor pattern. CONSTITUTION:A microwave circuit consisting of microwave transistors, etc., is formed on a ceramic substrate 2 fixed to a metal block 1 and sealed by a ceramic form 6 and a cover plate 5, etc. A input-output terminal of this microwave circuit is led on an end portion of the substrate 2 by a coplanar line 3 consisting of a central conductor pattern 3a and an earth conductor pattern 3b and the earth conductor pattern 3b is earthed to the metal block 1. In this manner, the metal block 1 and the ceramic substrate 2 can be made in a plate form, so that working cost can be reduced. Further, the input-output terminal portion can easily be connected to a test device by utilizing a high frequency probe, because said terminal portion is formed on the flat surface of the end portion 2a of the substrate 2.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a ceramic package for ultra-high frequencies that encapsulates microwave or millimeter wave circuits, and that facilitates connection with other external circuits without deteriorating the high-frequency characteristics. A microwave circuit is formed and sealed on a ceramic substrate fixed to a metal block, and the input/output terminals of the microwave circuit are connected from a center conductor pattern and a ground conductor pattern on the edge of the ceramic substrate. The ground conductor pattern was grounded to the metal block.

[Industrial application field]

The present invention relates to a ceramic package for ultra-high frequencies in which microwave or millimeter wave circuits are sealed.

2. Description of the Related Art Ceramic packages are known in which various circuits such as amplifier circuits and frequency conversion circuits for ultra-high frequency bands such as microwaves and millimeter waves are formed on a ceramic substrate and the ceramic substrate is sealed. It is necessary to perform circuit characteristic tests, etc. while sealed in this ceramic package, and there is a demand for a configuration that allows easy handling for this purpose.

[Conventional technology]

For example, as shown in the side view of FIG. 5 and the bottom view of FIG. (not shown) is sealed with a metal cover 26, and terminals are led out to the bottom surface by penetrating the ceramic substrate 20, 21 is an input terminal, 22 is an output terminal, 23 is a bias terminal, 24 is a control terminal, and 25 is a ground terminal. This ceramic package can be used up to about 18 GHz.

Further, in the conventional example shown in FIG. 7, a groove into which a ceramic wall 32 can be inserted is formed in a metal block 31, and the ceramic wall 3
Input/output terminals of a microwave circuit (not shown) are formed by a microstrip line 33 coaxially passing through the microstrip line 2, and 34 is a cover plate. This ceramic package can be used up to about 20 GHz.

Further, the width of the conductor patterns of the microstrip line on the microwave circuit side and the microstrip line 33 on the input/output terminal side is selected so as to have a characteristic impedance of, for example, 50Ω, and the portion that penetrates the ceramic wall 32 is For example, it is common to use a conductor pattern made of metal such as tungsten (W) and to narrow the width of the conductor pattern so as to obtain a characteristic impedance of 50Ω.

In addition, in the conventional ceramic package shown in FIG. 7, when testing a microwave circuit sealed by the lid plate 34, for example, as shown in FIG. A microstrip line 33 serving as an input/output terminal is connected to a microstrip line 43 formed on a ceramic substrate 42 on a metal block 41 on the test equipment side using a gold (Au) ribbon 44 to form a microwave circuit. and the test equipment. Alternatively, as shown in FIG. 9, one end of the contact spring 45 is fixedly connected to the microstrip line 33, and the other end is pressure-connected to the microstrip line 43 on the ceramic substrate 42 on the test device side. A configuration is used that connects the wave circuit and the test equipment.

Compared to the case where the microstrip lines 33 and 43 are connected to the gold ribbon 44, the connection using the contact spring 45 as shown in FIG. 9 makes it easier to connect and remove the ceramic package from the test device.

[Problem to be solved by the invention]

As mentioned above, the conventional ceramic package shown in FIGS. 5 and 6 has input/output terminals extending through the ceramic substrate 20, and is not easy to manufacture and is not suitable for ultra-high frequency bands of 20 GHz or higher. There was a drawback that it could not be used. Furthermore, the heat dissipation of the microwave transistor mounted on the ceramic substrate 20 is performed only through the ground conductor pattern formed with the ground terminal 25, and it is difficult to obtain sufficient heat dissipation characteristics. It had the disadvantage that it could not be equipped with an output transistor.

Furthermore, since the conventional ceramic package shown in FIG. 7 can radiate heat through the metal block 31, it is possible to mount transistors with a relatively large output.
It can be used in a high frequency band of about 0GH2. However, the ceramic wall 3 for leading out the input and output terminals in a coaxial type
2, it is necessary to form a groove in the metal block 31, and such processing of the metal block 31 increases the cost.

Further, as shown in FIG. 8, the microstrip line 33
．． 43 with a gold ribbon 44 to connect the sealed microwave circuit and the test device, the gold ribbon 4
Although it is a temporary connection according to No. 4, it has the disadvantage that test results cannot be obtained correctly unless it is connected correctly, and connection and disconnection are complicated. In addition, a gap as shown in the figure will be created between the metal block 31 of the ceramic package and the metal block 41 on the test equipment side, and the path on the ground side will connect the metal substrate that fixes the metal blocks 31 and 41. This has the drawback of deteriorating high frequency characteristics.

In addition, as shown in FIG. 9, in the configuration in which a contact spring 45 is used to connect to the microstrip line 43 on the test equipment side, the connection for testing the microwave circuit sealed in the ceramic package is Although it is much simpler than connecting with the gold ribbon 44, it requires a jig to hold down the contact spring 45 from above, and since the dielectric constant ε of this jig is not 1, the characteristic impedance is 50Ω. becomes unable to maintain. Also, since the tip of the contact spring 45 makes contact and is floating in the middle, the 20C
; In the band above Hz, it causes deterioration of high frequency characteristics, and has the disadvantage that accurate testing is difficult.

Further, an RF blower (coplanar type) is known to be capable of measuring parameters with high precision, and is used for measuring semiconductor chips. Using this RF blower, the seventh
It is conceivable to measure the conventional bar cage shown in the figure. However, it is difficult to make the ceramic surface on which the microstrip line of the buff cage is formed exactly the same as the adjacent metal block surface, and RF probers require extremely high planar accuracy. It was impossible to measure the conventional puff cage as shown in FIG. 7 using an RF prober.

An object of the present invention is to facilitate connection with other external circuits and to enable measurement using an RF blower without deteriorating high frequency characteristics.

[Means to solve the problem]

The ceramic package of the present invention is provided with coplanar line input/output terminals, and will be described with reference to FIG.

A microwave circuit is formed on a ceramic substrate 2 fixed to a metal block 1, sealed with a ceramic wall 6, a cover plate 5, etc., and the input/output terminals of this microwave circuit are connected to the end 2a of the ceramic substrate 2. A coplanar line 3 consisting of a center conductor pattern 3a and a ground conductor pattern 3b is used to connect the ground conductor pattern 3b to the metal block 1 through a via hole 4 or the like.

[Effect]

The coplanar line 3 consists of a center conductor pattern 3a and a ground conductor pattern 3b around it, and the ground conductor pattern 3b is grounded to the metal block 1 by a via pole 4, layered metal, wall pattern, etc. , an end portion 2a of the ceramic substrate 2 constituting an input/output terminal
A high frequency probe made of a coplanar line can be brought into contact with the top, making test connections extremely simple.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of the present invention, in which a microwave circuit consisting of a microwave transistor (not shown) is formed on a ceramic substrate 2 fixed on a metal block 1, and a ceramic wall 6 and A coplanar line 3 is formed on the end portion 2a of the ceramic substrate 2 by a center conductor pattern 3a and a ground conductor pattern 3b around it, so that the microwave circuit can be input. As an output terminal, the ground conductor pattern 3b is connected to the metal block 1.
It is connected to ground.

Although the grounding connection between the grounding conductor pattern 3b and the metal block 1 is shown in FIG. 1 through the via hole 4, it is also possible to connect the grounding conductor pattern 3b to the metal block 1 using a via hole 4. It can also be connected to ground. Further, the ground conductor pattern 3b and the metal block 1 can be grounded by a metalized wall pattern on the side surface of the ceramic substrate 2, etc. That is, the ground conductor pattern 3
b is extended and also formed on the side surface of the end portion 2a, and connected to the metal block 1. It is also possible to make a ground connection using a combination of these.

The coplanar line 3 is constructed by forming a center conductor pattern 3a and a ground conductor pattern 3b on a ceramic substrate (dielectric substrate) 2, and the electric field distribution is vertically symmetrical about these planes. becomes. On the other hand, in the microstrip line in the conventional example described above, a conductor pattern corresponding to the center conductor pattern is formed on a ground conductor corresponding to the above-mentioned ground conductor pattern via a dielectric substrate, The electric field distribution will occur mostly within the dielectric substrate between the conductor pattern and the ground conductor.

FIG. 2 is a cross-sectional view of the main part when the ground connection is made through the via hole 4. A metal layer is formed on the bottom surface of the ceramic substrate 2 by metallization or the like, and it is fixed to the metal block 1 by brazing or the like. The ground conductor pattern 3b on the end 2a of the ceramic substrate 2 and the metal layer on the bottom surface of the ceramic substrate 2 are connected by a conductor N4a on the inner surface of the via hole 4. Therefore, the center conductor pattern 3
The ground conductor pattern 3b around a can be connected to the metal block 1 through the shortest distance. Alternatively, a connection structure may be employed in which the inside of the via hole 4 is filled with a conductive paste or the like. Further, a ceramic wall 6 is fixed around the ceramic substrate 2, and the microwave circuit is sealed with a metal cover plate 5.

FIG. 3 shows the conductor pattern of the input/output terminal part, and the width of the center conductor pattern 3a is the same as that of the other parts in the part penetrating the ceramic wall 6. By increasing the distance from the center conductor pattern 3a at the penetrating portion, for example,
The structure is such that a characteristic impedance of 50Ω can be obtained. Therefore, the penetrating portion of the ceramic wall 6 is made of metal such as tungsten (W) to form the center conductor pattern 3a.
Even if the ground conductor pattern 3b is formed, the width of the center conductor pattern 3a is not narrowed, so the resistance value does not increase, and it is possible to prevent the high frequency characteristics from deteriorating.

Since the input/output terminal portion of the ceramic package is formed as a coplanar line on the end portion 2a of the ceramic substrate 2, the center conductor pattern 3a and the ground conductor pattern 3b are on the same plane. Therefore, it becomes possible to easily connect the high frequency probe 15 to the test equipment using a coplanar line. Note that in the conventional configuration shown in FIG. Due to the manufacturing precision of the wall 32, it is difficult to connect using a high frequency probe.

In addition, as shown in FIG. 4, when the coplanar line of the ceramic package and the coplanar line of the test equipment or other circuit are connected using a gold ribbon, the metal block 1 of the ceramic package and the metal of the test equipment or other circuit are connected. The block 11 is fixed on a metal substrate, and the ground conductor pattern 3b on the end 2a of the ceramic substrate 2 and the ground conductor pattern 13b on the ceramic substrate 12 are connected with a gold ribbon 14b, and The conductor pattern 3a and the center conductor pattern 13a on the ceramic substrate 12 are connected by a gold ribbon 14a. Therefore, even if a gap occurs between the metal blocks 1, 11, the grounding path will not become long, and a connection configuration that does not cause deterioration of high frequency characteristics can be obtained.

〔Effect of the invention〕

As explained above, the present invention forms and seals a microwave circuit consisting of a microwave transistor etc. on the ceramic substrate 2 fixed to the metal block 1, and on the end portion 2a of the ceramic substrate 2, The input/output terminals of the microwave circuit are derived from a coplanar line consisting of a center conductor pattern 3a and a ground conductor pattern 3b, and the metal block l and ceramic substrate 2 can be made into a flat plate shape, thereby reducing processing costs. becomes possible.

Furthermore, since the input/output terminal portion is formed on the end portion 2a of the ceramic substrate 2 and is a flat surface, it can be easily connected to the test equipment using a high frequency probe as explained with reference to FIG. It becomes possible. In addition, when making connections using gold ribbons, since both the center conductor pattern 3a and the ground conductor pattern 3b are connected by gold ribbons, the ground path is short (and the connection between metal block 1 and metal blocks of other circuits is short). Even if there is a gap between the center conductor patterns 3a, the high frequency characteristics will not be degraded.Since the ground conductor patterns 3b are interposed between the center conductor patterns 3a, there is an advantage that interference between the center conductor patterns 3a can be prevented. be.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a sectional view of essential parts of an embodiment of the invention, Fig. 3 is an explanatory diagram of a conductor pattern of an embodiment of the invention, and Fig. 4 is a gold ribbon. 5 is a side view of the conventional example, FIG. 6 is a bottom view of the conventional example, FIG. 7 is a perspective view of the conventional example, and FIG. 8 is an explanatory diagram of the gold ribbon connection of the conventional example. FIG. 9 is an explanatory diagram of a conventional spring connection. l is a metal block, 2 is a ceramic substrate, 2a is an end,
3 is a coplanar line, 3a is a center conductor pattern, 3b
is a ground conductor pattern, 4 is a via hole, 5 is a cover plate, 6
is a ceramic wall.

Claims (1)

[Claims] Ceramic substrate (2) fixed to metal block (1)
A microwave circuit is formed on the top and sealed, and the input/output terminals of the microwave circuit are connected to the end (2) of the ceramic substrate (2).
2a) is derived by a coplanar line (3) consisting of a center conductor pattern (3a) and a ground conductor pattern (3b), and the ground conductor pattern (3b) is grounded to the metal block (1). Ceramic package.