JP2016189418A - High frequency matching circuit board and microwave semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high frequency matching circuit board capable of transmitting power efficiently from an impedance of 50 Ω to the impedance of a semiconductor element, and to provide a high frequency matching circuit board and a microwave semiconductor device capable of achieving further compaction, while preventing increase in the number of components.SOLUTION: A high frequency matching circuit board 2 includes ceramic layers 3a-3e laminated downward in order. An impedance matching circuit 4a is provided on the upper surface of the ceramic layer 3a, and connected with the upper surface thereof. An impedance matching circuit 4b is provided between the ceramic layers 3b, 3c. An impedance matching circuit 4c is provided between the ceramic layers 3d, 3e. Ground patterns 6a-6c are provided just under the impedance matching circuits 4a-4c. The dielectric constant ε1 of the ceramic layer 3a is larger than the dielectric constant ε3 of the ceramic layer 3a, and the dielectric constant ε3 of the ceramic layer 3c is larger than the dielectric constant ε5 of the ceramic layer 3e.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-frequency matching circuit board that performs impedance conversion between a semiconductor element and input and output destination impedance (generally 50 ohms), and a terrestrial microwave communication device, satellite communication device, and the like using the same. The present invention relates to a microwave semiconductor device used as an amplifier.

  Microwave semiconductor devices are used in terrestrial microwave communication, satellite communication fields, and the like. With recent increases in communication capacity and system miniaturization in these fields, high output and miniaturization are required in microwave semiconductor devices. Usually, high output is realized by connecting semiconductor elements in parallel. As the semiconductor elements connected in parallel, a compound semiconductor element having a low impedance (1 ohm or less) such as gallium arsenide (GaAs) or gallium nitride (GaN) is usually used. The impedance of the input and output destination is generally 50 ohms, and it is necessary to convert the impedance from the 50 ohms to the impedance of the semiconductor element.

  As a means of converting impedance, generally, a matching circuit board that realizes appropriate characteristic impedance that converts impedance between a semiconductor element and an input and output destination in a metal package is arranged to make power efficient. Communicate well. The characteristic impedance is determined by the dielectric constant, substrate thickness, and line width of the single layer ceramic substrate. However, there are limits to the adjustment of the dielectric constant and thickness of a single single-layer ceramic substrate, and the line width is also limited by the size and current capacity of the microwave semiconductor device. It is difficult to transmit power efficiently.

  Therefore, a matching circuit having a plurality of single-layer ceramic substrates is used for each of the input and output sides. However, the number of parts to be mounted on the package is large, and a lot of time is required for manufacturing.

  On the other hand, the matching circuit board disclosed in Patent Document 1 is a single-layer ceramic board having a constant board thickness, and changes the dielectric constant stepwise or gradually from the input side to the output side. Appropriate characteristic impedance is achieved to solve the problem of increasing the number of parts.

  In addition, the matching circuit board disclosed in Patent Document 2 is provided with a cavity in a portion where the impedance matching circuit on the back side of the matching circuit board is formed, and an appropriate characteristic impedance is obtained by changing the thickness of the cavity. Realized and solved the problem of increasing the number of parts. Moreover, the degree of freedom for realizing the characteristic impedance is improved by filling the cavity with materials having different dielectric constants.

JP 2010-98500 A JP 2008-35336 A

  However, Patent Documents 1 and 2 have a problem that the high-frequency matching circuit board becomes large because the impedance matching circuit is configured on a single surface.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to efficiently transmit power from 50 ohms to the impedance of a semiconductor element, to prevent an increase in the number of parts, and to further reduce the size. It is possible to obtain a high-frequency matching circuit substrate and a microwave semiconductor device that can be realized.

  A high-frequency matching circuit board according to the present invention is provided on the upper surface of the first, second, third, fourth, and fifth ceramic layers sequentially stacked below, and on the semiconductor element. A first impedance matching circuit to be connected; a first ground pattern provided immediately below the first impedance matching circuit between the first ceramic layer and the second ceramic layer; and the second A second impedance matching circuit provided between the third ceramic layer and the third ceramic layer, and directly below the second impedance matching circuit between the third ceramic layer and the fourth ceramic layer. A second ground pattern provided; a third impedance matching circuit provided between the fourth ceramic layer and the fifth ceramic layer; and the fifth ceramic circuit. A third ground pattern provided immediately below the third impedance matching circuit on the lower surface of the first layer and the first and second ceramic layers, and the first and second impedance matching circuits A first via hole electrically connected to each other and a second via hole penetrating the third and fourth ceramic layers and electrically connecting the second and third impedance matching circuits to each other; The dielectric constant of the first ceramic layer is larger than the dielectric constant of the third ceramic layer, and the dielectric constant of the third ceramic layer is larger than the dielectric constant of the fifth ceramic layer. .

  In the present invention, the dielectric constant of the ceramic layer, which is one of the factors determining the characteristic impedance, is larger than the dielectric constant of the third ceramic layer, and the dielectric constant of the third ceramic layer is It sets so that it may become larger than the dielectric constant of a 5th ceramic layer. Thereby, the characteristic impedance can be transformed stepwise while minimizing the influence of the via hole, so that power can be efficiently transmitted from 50 ohm to the impedance of the semiconductor element. Further, by laminating ceramic layers, it is possible to prevent an increase in the number of parts and realize further miniaturization.

1 is a perspective view showing a microwave semiconductor device according to a first embodiment of the present invention. It is a perspective view which shows the microwave semiconductor device which concerns on Embodiment 2 of this invention.

  A high-frequency matching circuit substrate and a microwave semiconductor device according to an embodiment of the present invention will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repeated description may be omitted.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a microwave semiconductor device according to Embodiment 1 of the present invention. A high frequency matching circuit board 2 is connected to each of the input side and the output side of the semiconductor element 1. The high-frequency matching circuit board 2 includes ceramic layers 3a to 3e that are sequentially stacked below. The dielectric constants and thicknesses of the ceramic layers 3a to 3e are determined by the characteristic impedance that efficiently transmits power from 50 ohms to the impedance of the semiconductor element 1, and the dielectric constants are 1 to 300 and the thicknesses are 50 to 300 μm. preferable.

  An impedance matching circuit 4a is provided on the upper surface of the ceramic layer 3a. The semiconductor element 1 is connected by a wire 5 to the pattern of the impedance matching circuit 4 a of the high frequency matching circuit board 2.

  A ground pattern 6a is provided immediately below the impedance matching circuit 4a between the ceramic layers 3a and 3b. An impedance matching circuit 4b is provided between the ceramic layer 3b and the ceramic layer 3c. A ground pattern 6b is provided directly below the impedance matching circuit 4b between the ceramic layer 3c and the ceramic layer 3d. An impedance matching circuit 4c is provided between the ceramic layer 3d and the ceramic layer 3e. A ground pattern 6c is provided directly below the impedance matching circuit 4c on the lower surface of the ceramic layer 3e.

  The via hole 7a penetrates the ceramic layers 3a and 3b and electrically connects the impedance matching circuits 4a and 4b to each other. A via hole 7b penetrates the ceramic layers 3c and 3d and electrically connects the impedance matching circuits 4b and 4c to each other.

  Via hole 7c penetrates ceramic layers 3b-3e, and electrically connects ground patterns 6a-6c to each other. Package connection pads 8 connected to the package terminals by wires are provided on the upper surface of the ceramic layer 3a separately from the impedance matching circuit 4a. Via hole 7d penetrates ceramic layers 3a-3e, and impedance matching circuit 4c and package connection pad 8 are electrically connected to each other.

  The impedance matching circuit 4a on the uppermost surface (first layer) constitutes a microstrip line, and the third, fifth and fifth impedance matching circuits 4b and 4c constitute a strip line. The impedance matching circuits 4a to 4c and the ground patterns 6a to 6c are formed of a metal film such as Au (gold).

  In the present embodiment, the dielectric constant ε1 of the ceramic layer 3a is larger than the dielectric constant ε3 of the ceramic layer 3c, and the dielectric constant ε3 of the ceramic layer 3c is ceramic. It is set to be larger than the dielectric constant ε5 of the layer 3e (ε1> ε3> ε5). Thereby, electric power can be efficiently transmitted from 50 ohms to the impedance of the semiconductor element 1 by changing the characteristic impedance stepwise while minimizing the influence of the via hole. Further, by laminating ceramic layers, it is possible to prevent an increase in the number of parts.

  Further, with the above structure, not only the signal can flow in one direction on the plane, but also the signal can flow in the reverse direction by folding the pattern through the via hole. Accordingly, the length of the high-frequency matching circuit substrate 2 in the line length direction can be shortened to about 1/3, so that further downsizing can be realized.

  Further, the dielectric constants ε2 and ε4 of the ceramic layers 3b and 3d are close to the dielectric constant 1 of air (ε2, ε4≈1). Thereby, the impedance matching circuits 4b and 4c in the inner layer can be brought close to the microstrip line. Alternatively, the dielectric constant ε2 of the ceramic layer 3b may be the same as the dielectric constant ε3 of the ceramic layer 3c, and the dielectric constant ε4 of the ceramic layer 3d may be the same as the dielectric constant ε5 of the ceramic layer 3e (ε1> ε2 = ε3> ε4 = ε5 ). Alternatively, the dielectric constant ε2 of the ceramic layer 3b may be larger than the dielectric constant ε3 of the ceramic layer 3c, and the dielectric constant ε4 of the ceramic layer 3d may be larger than the dielectric constant ε5 of the ceramic layer 3e (ε1> ε2> ε3> ε4> ε5 ).

  In addition, the ceramic layer 3a has the highest dielectric constant and realizes a characteristic impedance close to the impedance (several ohms) of the semiconductor element 1, and thus greatly affects the electrical characteristics. By using the ceramic layer 3a as the uppermost layer and connecting the semiconductor element 1 to the pattern of the impedance matching circuit 4a provided on the upper surface of the ceramic layer 3a by the wire 5, the electrical characteristics can be finely adjusted.

Embodiment 2. FIG.
FIG. 2 is a perspective view showing a microwave semiconductor device according to the second embodiment of the present invention. In the first embodiment, the high-frequency matching circuit board 2 is connected to the input side and the output side of the semiconductor element 1, respectively. However, in this embodiment, two high-frequency matching circuit boards 2 have two impedance matching circuits 4a to 4c. And an input matching circuit and an output matching circuit connected to the input and output of the semiconductor element 1 respectively. A semiconductor element mounting pattern 9 on which the semiconductor element 1 is mounted is provided on the upper surface of the ceramic layer 3a between the input matching circuit and the output matching circuit. Via hole 7e penetrates ceramic layers 3a-3e and electrically connects semiconductor element mounting pattern 9 to ground pattern 6c. Package connection pads 8 are provided on the input side and the output side, respectively.

  Thus, by integrating the impedance matching circuit on the input side and the output side and providing the semiconductor element mounting pattern 9 between them, the positional error between the impedance matching circuit on the input side and the output side and the semiconductor element 1 is small. Stabilized characteristics can be expected.

  In the first and second embodiments, the six-layer structure in which five ceramic layers are stacked has been described. However, the number of ceramic layers to be stacked is not limited to this.

DESCRIPTION OF SYMBOLS 1 Semiconductor element, 2 High frequency matching circuit board, 3a-3e Ceramic layer, 4a-4c Impedance matching circuit, 5 wires, 6a-6c Ground pattern, 7a-7e Via hole, 9 Semiconductor element mounting pattern

Claims (6)

First, second, third, fourth, and fifth ceramic layers sequentially stacked below;
A first impedance matching circuit provided on an upper surface of the first ceramic layer and connected to a semiconductor element;
A first ground pattern provided immediately below the first impedance matching circuit between the first ceramic layer and the second ceramic layer;
A second impedance matching circuit provided between the second ceramic layer and the third ceramic layer;
A second ground pattern provided immediately below the second impedance matching circuit between the third ceramic layer and the fourth ceramic layer;
A third impedance matching circuit provided between the fourth ceramic layer and the fifth ceramic layer;
A third ground pattern provided immediately below the third impedance matching circuit on the lower surface of the fifth ceramic layer;
A first via hole that penetrates the first and second ceramic layers and electrically connects the first and second impedance matching circuits;
A second via hole penetrating the third and fourth ceramic layers and electrically connecting the second and third impedance matching circuits to each other;
The dielectric constant of the first ceramic layer is greater than the dielectric constant of the third ceramic layer,
The high frequency matching circuit board, wherein a dielectric constant of the third ceramic layer is larger than a dielectric constant of the fifth ceramic layer.   The high frequency matching circuit board according to claim 1, wherein the dielectric constant of the second and fourth ceramic layers is close to the dielectric constant 1 of air. The dielectric constant of the second ceramic layer is the same as the dielectric constant of the third ceramic layer;
The high frequency matching circuit board according to claim 1, wherein a dielectric constant of the fourth ceramic layer is the same as that of the fifth ceramic layer. The dielectric constant of the second ceramic layer is greater than the dielectric constant of the third ceramic layer,
The high frequency matching circuit board according to claim 1, wherein a dielectric constant of the fourth ceramic layer is larger than a dielectric constant of the fifth ceramic layer. The first, second and third impedance matching circuits constitute an input matching circuit and an output matching circuit connected to the input and output of the semiconductor element, respectively.
The high-frequency matching circuit board is:
A semiconductor element mounting pattern provided on an upper surface of the first ceramic layer between the input matching circuit and the output matching circuit;
And a third via hole that penetrates the first, second, third, fourth, and fifth ceramic layers and electrically connects the semiconductor element mounting pattern to the third ground pattern. The high-frequency matching circuit board according to claim 1, wherein: The high-frequency matching circuit board according to any one of claims 1 to 5,
A microwave semiconductor device comprising: the semiconductor element connected to a pattern of the first impedance matching circuit of the high-frequency matching circuit substrate by a wire.

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