JP3112253B2 - High frequency semiconductor device - 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 semiconductor device equipped with a high-frequency circuit element in a microwave band to a millimeter wave band, and more particularly to a semiconductor device and a circuit component without deteriorating the characteristics of a high-frequency signal. The present invention relates to a semiconductor device capable of transmitting data.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device equipped with a high-frequency circuit element for handling microwaves or millimeter waves, a high-frequency semiconductor element is housed in a semiconductor package having a dielectric substrate and a high-frequency transmission line formed therein. This semiconductor device is mounted on a surface of a predetermined external electric circuit board, and electrically connects a high-frequency transmission line of the semiconductor device to a high-frequency transmission line formed on the external electric circuit board to input and output a high-frequency signal. Is performed.

In such a mounting structure of a high-frequency semiconductor device, a package structure and a transmission line capable of inputting and outputting a signal without deteriorating a high-frequency signal are designed and manufactured, and an external electric circuit board is accurately mounted. A mounting technology for mounting a semiconductor device is required.

Conventionally, in this type of semiconductor device, as shown in FIGS. 4A and 4B, a cavity 42 formed by a dielectric substrate 40 and a lid 41 made of a dielectric material.
A high-frequency semiconductor element 43 is mounted therein and hermetically sealed. As shown in FIG. 4A, the input / output of the high-frequency signal and the mounting on the external electric circuit board are performed by connecting the high-frequency transmission line 44 such as a strip line connected to the high-frequency semiconductor element 43 to the wall 45. Through the cavity 42
It is pulled out to the outside, further disposed on the bottom surface via the side surface of the board, and the line formed on the bottom surface is connected to the external electric circuit board 4.
A semiconductor device soldered and mounted on a conductor layer 47 formed on the surface of No. 6 is proposed in, for example, Japanese Patent Application Laid-Open No. 61-168939.

[0005] As shown in FIG. 4 (b), a signal transmission line 48 is formed on the bottom surface of the dielectric substrate 40, and the transmission line 48 and the semiconductor element 43 are connected through a through-hole conductor 49. Semiconductor devices have been proposed. This semiconductor device is usually mounted by connecting a transmission line 48 to a conductor layer 47 of an external electric circuit board 46 by soldering or the like.

[0006]

However, FIG.
In (a), when the transmission line 44 passes through the wall 45, the signal line is converted from the microstrip line to the strip line at the wall passing portion, so that the signal line width needs to be reduced. As a result, there is a problem that reflection loss and radiation loss are apt to occur in the passing portion, so that the characteristics of the high-frequency signal are likely to deteriorate. Further, since the transmission line 44 is bent on the side surface of the substrate, when the transmission line 44 is used in a millimeter wave band,
The bending of the transmission line increases the reflection and makes it difficult to transmit and receive signals. Further, since the transmission line is formed on the side surface of the element mounting surface, the semiconductor device itself is inevitably large, and thus it is difficult to reduce the size of the circuit board. Moreover, in order to draw the transmission line 44 out of the cavity 42, at least the line passing portion of the wall needs to be formed of a dielectric material, which complicates the structure and increases the cost of the entire semiconductor device. I was

On the other hand, in FIG. 4 (b), since the signal does not pass through the wall by the through-hole conductor 49, the characteristic deterioration of the signal is small, but the operating frequency of the signal to be transmitted is 10G.
When the frequency is higher than Hz, the transmission loss in the through-hole conductor 49 sharply increases, so that it is difficult to transmit a signal in a microwave band to a millimeter wave band without characteristic deterioration.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-reliability high-frequency semiconductor device that has a small transmission loss in a high-frequency transmission line and has a simple structure and can be miniaturized.

[0009]

Means for Solving the Problems The inventors of the present invention have repeatedly studied a structure for reducing the loss and miniaturizing a wiring board for high frequency use, and as a result, have found that a wiring board formed of a dielectric substrate and wiring is provided. A first high-frequency transmission line electrically connected to the semiconductor element on the front side of the dielectric substrate, and a second high-frequency transmission line on the bottom side of the dielectric substrate. A transmission line is formed, and the first high-frequency transmission line and the second high-frequency transmission line are electromagnetically coupled to each other to transmit a high-frequency signal from the top surface to the bottom surface of the substrate without deteriorating transmission characteristics. I found what I could do. Further, a ground layer is formed on the surface of the dielectric substrate so as to surround the semiconductor element and the first high-frequency transmission line, and a lid made of a conductive material such as metal is attached to the ground layer to hermetically seal. By stopping, it is possible to form a small package with a simple structure, and at the same time, it is possible to protect the entire circuit, prevent the influence of external electromagnetic waves, and prevent the leakage of electromagnetic waves from the semiconductor device. .

That is, a high-frequency semiconductor device according to the present invention comprises a dielectric substrate, a high-frequency semiconductor element mounted on the surface of the dielectric substrate, and the high-frequency semiconductor device formed on the surface of the dielectric substrate. A first high-frequency transmission line electrically connected to the element, and an electric line formed on the surface of the dielectric substrate.
A source supply layer, a second high-frequency transmission line adhered to the bottom surface of the dielectric substrate, and a surface of the dielectric substrate surrounding the high-frequency semiconductor element and the first high-frequency transmission line. A first ground layer formed and adhered to the first ground layer;
A second ground formed in the electrical substrate and having a slot hole
A semiconductor layer for high frequency and a first ground layer.
And the first high-frequency transmission line is hermetically sealed.
A conductive lid attached, and the terminal end of the first high-frequency transmission line and the terminal end of the second high-frequency transmission line face each other via the slot hole. The first high-frequency transmission line and the second high-frequency transmission line are electromagnetically coupled, and the first ground layer and the second ground layer are electrically connected by a through-hole conductor formed in a dielectric substrate. And the power supply layer is drawn out to the bottom surface of the dielectric substrate via a through-hole conductor formed in the dielectric substrate.

According to the present invention, a semiconductor element is mounted on the front side of the dielectric substrate, and a first high-frequency transmission line electrically connected to the semiconductor element is formed. By forming the second high-frequency transmission line and electromagnetically coupling them in the dielectric substrate, the transmission line does not pass through the wall made of a dielectric or pass through a through-hole conductor or the like. Further, it is possible to provide a semiconductor device capable of minimizing reflection loss and radiation loss generated when a high-frequency signal passes through a line, and having a low transmission loss and a small size.

Further, the semiconductor element on the surface of the dielectric substrate or the first
Has a structure surrounded by a first ground layer formed therearound and a conductive lid electrically connected to the ground layer, so that the influence of external electromagnetic waves and This can be prevented.

Further, as an electromagnetic coupling structure between the high-frequency transmission lines, a second ground layer is formed in the dielectric substrate, and a slot hole is formed in the second ground layer. By forming the high-frequency transmission line and the second high-frequency transmission line at positions facing each other via the slot hole and electromagnetically coupling, it is possible to transmit a signal without loss of a signal between the transmission lines. Become.

Further, the first high-frequency transmission line and the second high-frequency transmission line
When the high-frequency transmission line is constituted by a microstrip line, a second ground layer is formed in a dielectric substrate, and the second ground layer and the first ground layer are electrically connected to each other, whereby the semiconductor Since the element has a structure in which the element is three-dimensionally completely surrounded by the ground layer, it is possible to further prevent the influence of external electromagnetic waves and leakage of electromagnetic waves.

[0015]

FIG. 1 shows an example of a high-frequency semiconductor device according to the present invention. According to FIG. 1, a high-frequency semiconductor device 1 has a cavity 4 formed by a dielectric substrate 2 made of a dielectric material and a conductive lid 3, and in the cavity 4, a semiconductor such as MMIC or MIC is formed. The element 5 is mounted. As the dielectric material constituting the dielectric substrate 2, ceramics having a dielectric constant of 20 or less, glass ceramics, ceramic metal composite materials, glass organic resin composite materials, and the like are desirable.

According to the present invention, in the cavity 4 of the semiconductor device, a line for transmitting a signal to the semiconductor element 5 is selected from a microstrip line, a strip line, and a coplanar line with ground. A first high-frequency transmission line 6 made of a seed is formed on the surface of the dielectric substrate 2. As shown in the plan view of the dielectric substrate 2 in FIG.
And the first high-frequency transmission line 6
Is formed on the first ground layer 7.
The conductive lid 3 is electrically connected to the ground layer 7 by a technique such as brazing or soldering. On the other hand, a second high-frequency transmission line 8 composed of one selected from a microstrip line, a strip line, and a coplanar line with ground is formed on the bottom surface of the dielectric substrate 2.

The conductive lid 3 is made of a conductive material capable of preventing the electromagnetic wave from the cavity 4 from leaking to the outside or leaking the electromagnetic wave to the outside, and is made of metal, conductive ceramics, ceramic metal composite material, or the like. Can be used. A conductive material may be applied to the surface of the insulating substrate. However, from the viewpoint of cost, metal is preferred.

FIG. 1 shows a structure in which the first high-frequency transmission line 6 and the second high-frequency transmission line 8 are microstrip lines. According to FIG. 1, the dielectric substrate 2
A second ground layer 9 made of a conductor layer is formed over substantially the entire surface, and a first signal transmission line 6 is formed by a strip conductor path 10 formed on the surface of the dielectric substrate 2 in the cavity 4. . Also, on the bottom surface of the semiconductor device 1,
A strip conductor path 11 is formed, and a second high-frequency transmission line 8 is formed between the ground layers 9.

In the ground layer 9, the slot holes 12 are formed.
The first signal transmission line 6 and the second signal transmission line 8 are connected via the slot hole 12 such that the end portions of the transmission lines 6 and 8 are arranged as shown in FIG. By forming them so as to face each other, the first high-frequency transmission line 6 and the second high-frequency transmission line 8 are electromagnetically coupled, and signal transmission without loss is performed. More specifically, the strip conductor paths 10 and 11 through the slot holes 12 are formed at opposing positions where the strip conductor paths 10 and 11 overlap with each other at a half wavelength of a required frequency transmission signal when viewed in plan. Preferably, the shape of the slot hole 12 is a rectangular hole having a long side and a short side, and the size thereof is appropriately set according to a used frequency and a frequency bandwidth. In particular, it is desirable that the long side of the slot hole has a length corresponding to １ ／ wavelength of the signal frequency, and the short side of the slot hole has a length corresponding to １ ／ wavelength corresponding to １ ／ wavelength.
It is desirable to set it to a length corresponding to 0 wavelength.

The strip line 11 of the second high-frequency transmission line 8 also has a function as a connection terminal when mounted on an external electric circuit board (not shown), and has a conductor layer formed on the external electric circuit board. And are electrically connected by brazing with solder or the like.

The first ground layer 7 formed on the surface of the dielectric substrate 2 is connected to the second ground layer 7 through the through-hole conductor 13.
Electrically connected to the ground layer 9, the semiconductor element 5 and the first high-frequency transmission line 6 mounted and formed on the surface of the dielectric substrate 2 are electrically connected to the conductive lid 3 and the first ground layer 7. In addition, the semiconductor device is three-dimensionally surrounded by the second ground layer 9 to prevent a malfunction of the semiconductor element due to an external electromagnetic wave, and to prevent leakage of the electromagnetic wave to enhance the reliability of the semiconductor device. it can.

The cavity 4 in the semiconductor device shown in FIG. 1 has a semiconductor element 5 and a strip conductor path 10 forming the first signal transmission line 6 and a power supply for supplying power to the semiconductor element 5. A power supply layer 14 is formed. Since the power supply layer 14 has a low frequency, it is not necessary to form the power supply layer 14 with a special high-frequency line. Therefore, the power supply layer 14 is made of a dielectric material via a through-hole conductor 15 formed in the dielectric substrate 2. It is pulled out to the bottom surface of the board 2 and is electrically connected to a conductor layer of an external electric circuit board (not shown).

The ends of the strip conductor 10 and the power supply layer 13 are connected to the semiconductor element 5 and a ribbon, wire, T
AB (Tape Automated Bonding) or the like, each of which is electrically connected. In particular, the semiconductor element 5 can be connected directly without any transmission loss by being directly mounted on the strip conductor path 10 by solder, gold bump, or the like. it can. The connection method between the conductor path 10 and the semiconductor element 5 is not limited to this. For example, a connection method may be used in which a connection is made by gold ribbon or several wire bondings, or a conductor in which a conductor such as Cu is formed on a substrate such as polyimide. It can also be connected by a plate or the like.

Next, the transmission characteristics of the high-frequency semiconductor device shown in FIGS. 1 and 2 were determined. As the dielectric, a dielectric constant of 5.6, a dielectric loss of 31.0 × 10 ⁻⁴ (measurement frequency of 60 G
(Hz) using a dielectric material and copper as a conductor to fabricate a wiring board, and use a network to measure the transmission characteristics at the input part of the wiring board.
It was measured by a analyzer. FIG. 3 shows the result. From FIG. 3, two electromagnetic coupling portions and a total length of 8 mm
At 60 GHz, transmission characteristics of S11: -25 dB and S21: -1.7 dB or more were obtained, and it was shown that the loss was extremely low.

[0025]

As described above in detail, the high-frequency semiconductor device of the present invention is characterized in that the high-frequency transmission line on the surface of the dielectric substrate and the high-frequency transmission line formed on the bottom surface of the dielectric substrate are electromagnetically coupled. Accordingly, since the transmission line does not pass through a wall or the like for forming a cavity, it is possible to transmit a signal between the transmission lines with low transmission loss. Moreover, since the cavity for accommodating the semiconductor element is formed by attaching the conductive lid to the ground layer on the surface of the dielectric substrate, the cavity has a very simple structure and is prevented from being affected by external electromagnetic waves. In particular, by electrically connecting to a ground layer formed in a dielectric substrate, the effect can be further enhanced, and a high-reliability semiconductor device that can be miniaturized with high reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a high-frequency semiconductor device according to the present invention.

FIG. 2 is a plan view of a surface of a dielectric substrate of the semiconductor device of FIG. 1;

FIG. 3 is a diagram illustrating transmission characteristics of the semiconductor device of FIG. 1;

FIG. 4 is a schematic view of a conventional high frequency semiconductor device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-frequency semiconductor device 2 dielectric substrate 3 conductive lid 4 cavity 5 semiconductor element 6 first high-frequency transmission line 7 first ground layer 8 second high-frequency transmission line 9 second ground layer 10 strip conductor path 11 Strip conductor path 12 Slot hole 13 Through hole conductor 14 Power supply layer 15 Through hole conductor

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-250913 (JP, A) JP-A-8-250911 (JP, A) JP-A-9-186268 (JP, A) JP-A-10-108 313078 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/12-23/12 301 H01L 23/02 H01P 5/02

Claims (1)

(57) [Claims] 1. A dielectric substrate, a high-frequency semiconductor element mounted on the surface of the dielectric substrate, and a second semiconductor element formed on the surface of the dielectric substrate and electrically connected to the high-frequency semiconductor element. A high-frequency transmission line and a surface covered with the dielectric substrate.
A power supply layer formed thereon, a second high-frequency transmission line formed on the bottom surface of the dielectric substrate, and the dielectric layer surrounding the high-frequency semiconductor element and the first high-frequency transmission line. A first ground layer formed on the surface of the dielectric substrate, and a slot hole formed in the dielectric substrate.
A second ground layer, and the first ground layer
The semiconductor element and the first high-frequency transmission line are hermetically sealed.
A conductive lid attached so as to be sealed, and an end portion of the first high-frequency transmission line and the second high-frequency transmission line.
Facing the end of the wave transmission line via the slot hole
Then, the first high-frequency transmission line and the second high-frequency transmission line are electromagnetically coupled to each other, and the first ground layer and the second high-frequency transmission line are connected to each other.
And the ground layer is electrically connected by a through-hole conductor formed in the dielectric substrate, and the power supply layer is drawn out to the bottom surface of the dielectric substrate through the through-hole conductor formed in the dielectric substrate. A high-frequency semiconductor device, comprising: