JPH03201701A - Microwave device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a microwave device such as a microwave converter used in a satellite broadcast receiver.

<Prior Art> In recent years, small-sized microwave devices have been manufactured using microwave integrated circuits. There are two types of microwave integrated circuits: hybrid microwave integrated circuits (HMIC) and monolithic microwave integrated circuits (MMI C).
Compared to MICs, they are smaller, require no adjustment, and are highly reliable, and have been particularly actively developed recently. In order to mount this MMIC in a microwave device such as a converter, for example, the MMIC is packaged and then attached to a dielectric substrate using solder or the like. Recently, as shown in FIG. 3, after the MMIC chip 12 is die-bonded to a metal carrier 31 such as Tacovar, which is connected to a dielectric substrate 34, microstrip lines 32 and wires 33 on the dielectric substrate 34 are bonded. A method of connecting with .

<Problems to be Solved by the Invention> The conventional MMIC mounting method has the following problems.

(1) When a package is used, the MMIC will not lose its original characteristics due to the influence of the capacitance of the package and the inductance of the bonding wire within the package.

(2) The use of a package increases the installation area of the MMIC, which also leads to an increase in cost.

(3) Impedance mismatch due to variations in package input/output capacitance and wire inductance degrades the performance of microwave devices.

(4) In the case shown in FIG. 3, the package is not necessary, but instead the surface of the MMIC chip needs to be protected, and the influence of the inductance of the bonding wire in the casing cannot be eliminated.

Due to the above-mentioned problems, the current situation is that microwave devices using MMICs have not achieved much higher performance and smaller size than those using HMICs.

In addition, HMICs are manufactured by mounting field-effect transistor or diode chips mainly made of GaAs in a package, and then mounting them on a dielectric substrate using solder flow. I have a similar problem.

The present invention aims to mount element chips without using packages or wires that cause these problems.

Means for Solving the Problems> In order to achieve the above object, the present invention provides a microelectronic microelectronic substrate in which an element chip is mounted on a dielectric substrate having grounded 'FL' poles on the front and back surfaces and a transmission line conductor formed inside. In the wave device, the substrate has an opening, an element chip is housed in the opening, an electrode terminal of the element chip is connected to the transmission line conductor using a bump electrode, and the opening is sealed. To provide a microwave device characterized by:

The dielectric substrate of the present invention has a structure of, for example, a balanced line, a J-tube line, and the element chip is an MMI C.
, FET, MODFET (modulation doped field effect transistor), diode, etc. The opening for housing the element chip may penetrate through the dielectric substrate, or
It doesn't have to be through. When not penetrating, it is preferable that the bottom surface of the opening be located at the same position as the surface on which the transmission line conductor is formed, so that the transmission line conductor is exposed on the bottom surface.

For sealing the opening, it is preferable to cover the opening using a conductive sealing body, and for a more preferable case, it is preferable to cover the opening using a thin metal plate. To ground the element chip, it is best to provide a ground electrode on the back surface of the element chip, connect the ground electrode to the conductive sealing body, and connect it to one of the ground electrodes on the dielectric substrate. In order to ground the ground electrode, it is preferable to lead a connection part from another ground electrode on the dielectric substrate to the position of the transmission line conductor, and connect the ground electrode to this using a bump electrode.

<Function> In the present invention, the dielectric substrate also serves as a package by placing the element chip in an opening provided in the dielectric substrate and sealing the opening. Also.

When a conductive sealing body is used for the sealing and is electrically connected to the ground electrode of the dielectric substrate, the element chip is electrically shielded by the ground electrode of the dielectric substrate and the sealing body. moreover,
Connecting element chips using bump electrodes eliminates the need for conventional bonding wires, and the length of the electrodes at the connection portion is also much shorter than with bonding wires.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a partial sectional view of the microwave down converter of this embodiment, and FIG. 2 is a circuit configuration diagram thereof.

The microwave downconverter of this embodiment is configured such that the MMIC chip constituting the device is housed in an opening in a dielectric substrate. The structure of this portion will be explained with reference to FIG. 1 along with the manufacturing method. The dielectric substrate 2 is manufactured as follows. Dielectric 5゜ground electrode 3, transmission line metal 7-3
A through hole 13 is provided in a substrate made of layers, and a metal plate 1 having a convex portion 10 with a height approximately equal to the thickness of the substrate is connected to a ground electrode 3.
The convex portion 10 is inserted into the through hole 13 for connection. To this, the two layers of the ground electrode 4 and the dielectric 6 are cut out, and a substrate with a through hole provided therein to form the opening 14 is bonded to form the dielectric substrate 2. The opening 14 is larger than the through hole 13, the protrusion 10 and the transmission line metal 7 are exposed within the opening 14, and the size of the opening 14 is large enough to accommodate the MMIC chip 12.

The MMIC chip is manufactured by forming Au bumps or electrodes 9a and 9b on the ground electrode terminal and input/output electrode terminal on the front surface of the MMIC chip 12 by electrolytic plating, etc., and depositing the electrodes containing Au as the main metal on the back surface to form a thin film metallization layer. The one in which L'll is formed is used. Then, the bump electrode 9 on the surface of this MMIC chimp 12
a, and the convex portion 10. The bump electrode 9b and the transmission line metal 7 are connected, the R/IMIC chip 12 is mounted on the dielectric substrate 2, the thin metal plate 8 is connected to the thin film metal/l/ll and the ground electrode 4, and the opening 14 is sealed. do. As described above, the opening 14K MMIC chip 12 of the dielectric substrate 2 has the ground electrode 4.3 formed on the front and back surfaces and the transmission line metal 7 formed inside.
can be paid. In this structure, the MM/rc chip 12 is sealed by the dielectric weir plate 2, the metal plate 1, and the metal thin plate 8, and the electrode terminals on the surface of the MMIC chia 7'12 are connected by bump electrodes. The back surface is grounded to the ground electrode 4 by a thin metal plate 8.

In the conventional connection of MMIC chips using wires, the inductance due to the wire was 0.5 nH or more, but in the connection using the bump electrodes of this embodiment, the bump electrodes 4i9a,
The height of 9b is small, about 100 μm, and the inductance is also small, about 0.1 nH.

As shown in FIG. 2, the microwave downconverter of this embodiment includes a microwave signal input terminal 20, a microwave low noise amplifier 2+, a filler 22, a mixer 23, a local oscillator 24, an intermediate frequency amplifier 25, an intermediate frequency 26, and the MMIC chip has the functions of each or more of the above parts.

When this down converter is used at 10 GHz, the impedance generated at each part of the connection electrode is reduced, and the influence of variations due to connection is also reduced. Cabinet,
Since no package is used, the high frequency characteristics of the MMIC chip are reflected in the characteristics of the converter without being affected by the capacitance of the package. Furthermore, the back side of the MMIC chip and the ground electrode were short-circuited with a metal plate, and the casing
Since the signal line is a strip line, MMIC
The chip operates in an electrically shielded structure and MMI
Surge is difficult to enter in C. There is no need to specifically protect the cased MMIC with a surface protective agent.

As described above, the down converter manufactured according to the present invention can maximize the characteristics of the MMIC chip, and can achieve higher performance, smaller size, and higher reliability.

The substrate used in this example is the upper layer V of the MMIC chip.
It is also possible to further increase the number of layers by connecting power supply circuits. The ground metal 3 and the MMIC chip surface ground electrode are nulled by making the thickness of the cut dielectric 5 about several hundred/1 m.
It is also possible to connect by holes, in which case the metal plate l is not required.

<Effects of the Invention> According to the present invention, a microwave device can be manufactured without using a package or wires, so the original characteristics of the element chip can be maximized, and variations in inductance due to connections can be reduced. This will not cause impedance mismatch or transmission loss. Furthermore, it is possible to further reduce the size and cost of the device. Furthermore, by using a conductive sealing body, a microwave device with excellent surge properties can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a down converter according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the down converter, and FIG. 3 is a diagram of a conventional MMIC mounting structure. 1... Metal plate 2... Dielectric substrate 3.4... Ground electrode 7... Transmission line metal 8... Metal thin plates 9a, 9b... Bump electrode 12... MMIC chip 14. ··Aperture

Claims (1)

[Claims] 1. A microwave device in which an element chip is mounted on a dielectric substrate having ground electrodes on the front and back sides and a transmission line conductor formed inside, the substrate having an opening, and the element chip being mounted in the opening. What is claimed is: 1. A microwave device, characterized in that the device chip is housed in a device, electrode terminals of the element chip are connected to the transmission line conductor using bump electrodes, and the opening is sealed.