JPH03135058A - Microwave circuit component - Google Patents

Abstract

PURPOSE:To enhance a design property and a breakdown-strength yield of an impedance matching circuit by a method wherein a space interconnection conductor and a surface metal layer formed on the surface of an insulating substrate under it are connected to a metal layer on the rear so as to be passed through the substrate and a desired electrostatic capacity is obtained. CONSTITUTION:A hole is made in an alumina substrate; a through hole is filled with a metal such as Mo or the like; and a protrusion is poslished and flattened. Au/Pt/Ti are vapor-deposited on both faces of the substrate and are patterned; a metal layer 13 is formed. The whole layer 13 is covered with a resist; Au/Pt/ Ti are vapor-deposited and patterned; and a microstrip line 11 and an open stub 104 are formed. The metal layer 13 on the substrate is connected electrically to a rear metal 15 of the substrate by using a metal plug 14 which has been filled in the through hole; a space interconnection conductor 11a is insulated from the metal layer 13 via an air layer 12 at the lower part; and an electrostatic capacity is obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) A metal layer is fixed to both sides of an insulating substrate as one of the impedance matching circuit components of a microwave semiconductor device, and the surface metal layer is etched. to form a desired pattern, such as a microwave transmission line, and form other lumped constant elements, such as a microwave transmission line, to form other lumped constant elements 2, such as thin film resistors, MIM (metal-dielectric-metal) Some are equipped with capacitors. An example is shown in FIG. 3 and will be explained.

The back surface of the alumina substrate 101 is made of Au/Pt/T.
A metal layer 102 consisting of i is formed by vapor deposition,
Also formed on the surface of this substrate are a microstrip line 103 made of Au/Pt/Ti, an open stub 104, an MIM capacitor 105, and the like.

As shown in an enlarged cross-sectional view in FIG. 4, the MIM capacitor 105 includes a metal layer 106 electrically connected to the microstrip line 103, a dielectric 108. and a metal layer 107 on the substrate. Further, the metal layer 107 on the substrate is electrically connected to the back metal layer 102 through a lead-out semiconductor 109 and a through hole 110. That is, the MIM capacitors 105 are connected in parallel in a circuit, that is, the MIM capacitors 105 are connected in parallel in a circuit, and have an important function as an impedance matching circuit element.

(Problem to be Solved by the Invention) The structure of the conventional MIM capacitor described above has the following serious problems. That is, as shown in FIG.
It is represented by the capacitance C generated between the two and the inductance L generated at the lead-out conductor 109. Therefore,
As the frequency increases, the capacitive reactance, which is its original function, gradually becomes smaller, and when the frequency exceeds 1/(2πm>, it becomes an inductive reactance, making the design of an impedance matching circuit extremely complicated and difficult. Become.

In addition, when forming the MIM capacitor, a nitride film (Sl, N4) or an oxide film (Sin, ) is used as the dielectric 108.
etc. using plasma CVD equipment (CVD: Chemi
Cal VaporDeposition), etc. However, the film quality of this insulating film largely depends on the underlying alumina substrate and the surface roughness of the metal layer, so the breakdown voltage of the MIM capacitor required when DC and microwaves are applied is There are many variations in size, which poses a serious problem in that it greatly reduces the yield of capacitors.

The present invention has been made in view of the above-mentioned conventional problems.
The purpose of the present invention is to provide a microwave component that has an excellent impedance matching circuit design and can significantly improve the withstand voltage yield.

[Structure of the invention]

(Means for Solving the Problems) A microwave circuit component according to the present invention includes a microwave circuit component formed on an insulating substrate including a microstrip line, and a part of the conductor formed by the microstrip line. A space wiring conductor provided, a surface metal layer having a desired area provided on the surface of the space wiring conductor and the insulating substrate under the space wiring conductor, and a surface metal layer that penetrates the surface metal layer and the insulating substrate under the surface metal layer and then passes through the back surface of the space wiring conductor. The space wiring conductor and the surface metal layer are characterized in that the space wiring conductor and the surface metal layer are configured to have a desired capacitance via an air layer.

(Function) With the microwave circuit component of the present invention, it is possible to significantly improve the design of the impedance matching circuit, which has been a problem in the past, and the decrease in yield due to poor withstand voltage. Using this method, high-performance and inexpensive microwave semiconductor devices can be manufactured.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. In addition, in the description, parts that are the same as in the prior art are shown in the drawings with the same numbers as in the prior art, and the explanation will be omitted.

The microstrip line 11 on the alumina substrate 101 is space-wired at a desired location, and the alumina substrate 101 is placed below the space wiring conductor 11a via an air layer 12.
A metal layer 13 on the substrate is formed thereon. Further, the metal layer 13 on this substrate is connected to the rear surface metal layer 13 of the substrate by a metal column 14 (conductive connection body part) filled with, for example, molybdenum (No) in a through hole formed in the alumina substrate 101.
electrically connected to.

The microwave component described above is formed by the following method.

First, a through hole is formed in an alumina substrate by using a laser beam or by providing an opening before sintering the alumina substrate and then sintering the alumina substrate. Next, the through hole is filled with MO or the like, and the portion protruding from the surface of the alumina substrate is polished to make it flat. Next, Au/Pt/Ti is vapor-deposited on both sides of the alumina substrate, and a metal layer 13 on the substrate is formed by patterning using a resist. Next, the metal M on the above substrate! The entire J13 is coated with a resist, Au/Pt/Ti is deposited, and then patterned to form the microstrip line 11 and the oven stub 104.

In the above embodiment, Au/Pt/T is used as the metal layer for space wiring.
Although the case where i is used is illustrated, the present invention is not limited to this, and in order to increase the mechanical strength of the metal layer, a No layer or the like may be further added as a base metal layer.

〔Effect of the invention〕

According to the present invention, as described above, the circuit design of microwave components is greatly improved and the yield is also greatly improved, so it is desirable to improve the performance and lower the cost of microwave semiconductor devices using the same. It has a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a microwave component according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of a part of FIG. 1, and FIG. 3 is a perspective view of a conventional microwave component. , Figure 4 is the third
FIG. 5, which is a sectional view showing a part of the figure enlarged, is an equivalent circuit diagram of the MIM capacitor. 11...Microstrip line 11a...Space wiring conductor 12...Air layer 13...Metal layer 1 on the board
4...Metal pillar (conductive connection body part) I5...Back metal layer

Claims (1)

[Claims] A microwave circuit component formed on an insulating substrate and including a microstrip line includes a space wiring conductor provided on a part of a conductor forming the microstrip line, and a space wiring conductor that is connected to the space wiring conductor. A surface metal layer with a desired area provided on the surface of the insulating substrate under the space wiring conductor, and a conductive connector that penetrates the surface metal layer and the insulating substrate under the surface metal layer and electrically connects the metal layer on the back surface. A microwave circuit component, characterized in that the space wiring conductor and the surface metal layer have a desired capacitance via an air layer.