JPS6249988B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, particularly a semiconductor device suitable for a high frequency, high output transistor.

In the past, high-frequency, high-power transistor RF
In order to improve the characteristics, the following was considered. Bipolar devices usually have a transistor chip substrate as the collector region, so when using this chip, in order to form a normal emitter-grounded or base-grounded circuit, grounding inductance will necessarily occur due to the bonding wire, and this grounding inductance By reducing , the characteristics of the transistor chip can be improved.

However, as attempts were made to reduce the grounding inductance by making various improvements to the device container, it became clear that the grounding inductance also greatly contributed to stable operation in actual high-output characteristics. The same effect as the emitter ballast resistor provided is observed. From this point of view, a design concept that actively utilizes the above-mentioned grounding inductance for stable operation is currently becoming common. Normally, the smaller the ground inductance, the larger the value of the emitter ballast resistance within the chip must be, which reduces the power gain. In addition, the higher the power consumption of the chip, the greater the ballast resistance value inserted into each emitter stripe, and the standardization of transistor chips has become increasingly difficult in order to achieve stability for each transistor's various uses. I will be exposed. Furthermore, in order to achieve stability, the RF characteristics had to be significantly degraded. This is due to the fact that a bridge made of a material such as metal has conventionally been provided on the output side of the element container of a high-frequency, high-output transistor. The above-mentioned stabilizing operation by the grounding inductance cannot be obtained by a bridge that generates a grounding inductance component that is not connected to each unit chip, and only causes losses such as a reduction in power gain as a feedback parasitic element. Ta.

In order to solve these drawbacks, device containers and the like having through-hole portions have been proposed. However, even this type of device container is not sufficient for achieving stability and optimization of characteristics of transistor devices. In other words, in such a device container, in order to maintain the stability of the transistor device, the transistor chip is mounted close to the output side, and the bonding wire that connects the transistor chip and the ground metallization having through-holes allows the transistor chip to be mounted close to the output side. The RF ballast resistance of the inductance component (hereinafter referred to as inductor ballast resistance) can be increased, but the operation Q on the input side, which is composed of the bonding wire and transistor chip that connects the input terminal and the chip, becomes larger, resulting in a narrower band and destabilize. On the other hand, if the chip is mounted close to the input side in order to lower the operational Q of the input side, which is composed of bonding wires and transistor chips that connect the input terminal and the pellet, the disadvantage is that the grounding inductor ballast resistance cannot be increased. There is.

As explained above, in order to obtain stable high frequency operation in a conventional device container, a sufficiently large emitter stabilizing resistor is required in the transistor chip. This has forced a significant sacrifice in power gain, which has been considered a major problem in bringing out the inherent RF operation capabilities of transistor chips.

It is an object of the present invention to improve the quality of transistor devices by eliminating all of the above-mentioned disadvantageous factors.
The object of the present invention is to provide an element container suitable for stable operation at high gain and high output without sacrificing RF characteristics.

That is, in the device container according to the present invention, the transistor chip is housed near the center, and the ground metallization and through holes, which were on the input side in this embodiment, are placed on the output side, thereby eliminating the need for a bridge and connecting the input terminal This minimizes the distance between metallization and chips. By mounting a transistor chip in this configuration, the length of the bonding line connecting the input terminal metallization and the transistor chip is less than half that of the conventional one, and the input side consists of the grounding bonding wire and the element. Since the operation Q of is lowered, stable RF operation can be obtained. In addition, since the grounding metallization is installed with a certain width near the output side, the length of the grounding bonding wire can be selected independently without depending on the chip mounting position, making it possible to adjust the grounding inductor ballast resistance. Become. Therefore, the operation Q of the input side bonding line and the arrangement of the grounded inductor and ballast resistor can be independently optimized and configured.

Next, the structure of a device container according to the present invention and a high frequency transistor constructed using this device container will be explained in more detail while comparing with the structure of a high frequency transistor using a conventional device container shown in FIG.

In FIG. 1a, the transistor chip 1 is mounted directly on the output terminal collector metallized portion 3 of the element container 2, and the emitter grounding bonding wire 4
is grounded to the emitter grounding metallized part 5,
An emitter grounding bonding wire 6 connects the emitter to an emitter grounding bridge 7 . Further, the input terminal base metallized portion 8 is connected from the transistor chip 1 by a bonding line 9 for connecting the input terminal. Bonding wire for emitter grounding 4,
6 indicates each unit transistor electrode of transistor chip 1, emitter grounding metallization 5, and bridge 7.
and are directly connected to.

In general, the stability of a transistor element is determined by the emitter ballast resistance of each unit transistor electrode.
The emitter grounding bonding wires 4 and 6 connecting each electrode to the emitter grounding metallization 5 and the bridge 7 are connected by grounding inductor ballast resistors. However, when the emitter-grounded metallization 5 and bridge 7 are not directly connected to each unit transistor electrode, the inductance component of the emitter-grounded metallization 5 and bridge 7 does not contribute to the stability of the transistor element, and the feedback It acts as a parasitic element and only causes losses such as a decrease in power gain.
To eliminate this loss, the emitter grounding bridge can be removed to eliminate the inductance component. Furthermore, as shown in FIG. 1B, by providing through holes 10 in the emitter grounding metallization 5, the inductance component of the emitter grounding metallization 5 can be reduced.

However, the semiconductor device using the conventional element container in this conventional example has the following drawbacks.

The inductor ballast resistance of the emitter grounding bonding wire 4 that connects the transistor chip 1 and the emitter grounding metallization 5 improves the stability of the transistor element by reducing the inductance component due to the through hole 10 provided in the emitter grounding metallization 5. It has contributed greatly. In order to maximize this effect, it is necessary to increase the grounded inductor ballast resistance by moving the mounting position of the transistor chip 1 away from the emitter grounding metallization 5 and lengthening the connected emitter grounding bonding wire 4. However, since the input terminal connection bonding line 9 that connects the input terminal base metallization 8 and the transistor pellet 1 becomes long, the bonding line 9 and the transistor chip 1
The input-side motion Q formed by . As a result of the above, the transistor element characteristics become narrow band and unstable. Furthermore, in order to reduce the operation Q on the input side, the mounting position of the transistor chip 1 is moved closer to the input terminal base metallization 8, and the length of the input terminal connection bonding wire 9 is shortened. The bonding wire 4 for grounding the emitters connecting the transistors becomes shorter, the grounding inductor ballast resistance becomes smaller, and the effect of stabilizing the transistor element is reduced.

In other words, the conventional device container mentioned in this conventional example has the drawback that the wide band and stability achieved by the input-side operation Q of the transistor element and the stability of the transistor achieved by the grounded inductor ballast resistance cancel each other out. .

As mentioned above, semiconductor devices using conventional device containers have broadband characteristics in high frequency operation,
In terms of stability, there are drawbacks due to the factors mentioned above.

FIGS. 2a and 2b show an embodiment of a high frequency transistor using an element container according to the present invention.

As shown in FIG. 2a, the device container according to the present invention is provided with the conventional emitter grounding metallization 5 on the output side 12, so that the input terminal base metallization 8 is replaced by the output terminal collector metallization 3.
It can be brought close to the transistor chip 1 mounted on the PC. Therefore, since the length of the input terminal connecting bonding line 9 is shortened, there is an advantage that the operation Q on the input side constituted by the input impedance of the bonding line 9 and the transistor chip 1 can be lowered. Further, since the length of the emitter grounding bonding wire 10 can be adjusted regardless of the length of the input terminal connecting bonding wire, there is an advantage that the grounding inductance and the grounding inductor ballast resistance can be made convenient.

More specifically, when the transistor chip 1 is moved on the output terminal collector metallization 3, as the chip approaches the emitter ground metallization 12, the emitter ground bonding line 11 becomes shorter and the input terminal ground bonding line 9 becomes longer. Therefore, the operational Q becomes high and the inductor ballast resistance becomes small. In other words, the stability of the transistor element deteriorates. Next, by bringing the chip closer to the input terminal base metallization 8, the input terminal grounding bonding line 9 becomes shorter and the emitter grounding bonding line 11 becomes longer, so the operation Q decreases and the transistor element due to the grounding inductor ballast resistance becomes shorter. This will improve stability.
This eliminates the effect of offsetting the stability due to the mounting position of the chip, making it possible to have an optimal arrangement.

In addition, after optimizing the arrangement of the transistor chip 1 and optimizing the operation Q on the input side,
By selecting the grounding position of the emitter grounding bonding wire 11 with respect to the emitter grounding metallization 12, the grounded inductor balance resistance can be adjusted without reducing the above-mentioned effects.

As described in detail above, according to the structure of the semiconductor device container according to the present invention, various drawbacks of conventional high frequency, high output transistors can be eliminated, and a device with high performance and high reliability can be realized.

Although this embodiment has been described using a circuit configuration in which the emitter of a bipolar element is grounded, it is clear that the effects of the present invention can also be obtained in the case of a circuit configuration in which the base is grounded.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing an example of a conventional high frequency high power transistor, FIG. 1 b is a cross-sectional view taken along the plane A-A, and FIG. FIG. 1B is a plan view showing an embodiment of the present invention, and FIG. 1...Transistor chip, 2...Element container,
3... Output terminal collector metallized part, 4... Bonding wire for emitter grounding, 5... Emitter grounding metallized part, 6... Bonding wire for emitter grounding, 7... Bridge for emitter grounding, 8...
Input terminal base metallized part, 9... bonding wire for input terminal connection, 10... through hole, 12
... Emitter grounding metallized part, 11... Emitter grounding bonding wire.

Claims (1)

[Claims] 1. An input/output metallization layer is formed on an insulating substrate with good thermal conductivity, a transistor chip is mounted on the output metallization layer, and a ground metallization layer is formed on the insulating substrate surrounded by the output metallization layer. . A semiconductor device comprising a through hole that connects a metallized layer formed on the back surface of the insulating substrate and the ground metallized layer.