JPS6041864B2 - Method for forming metallized layer on insulating substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a metallized film (metalized layer) on an insulating substrate of a semiconductor container made of an insulating substrate such as a ceramic.

Potassium arsenide field effect transistor (hereinafter referred to as G.A.
FET (FET) is a Ξ terminal element that can amplify and oscillate even in the microwave band of 4GH2 or higher, so it is put into practical use as a main microwave band device instead of the diode that has been mainly used in this frequency band. has been made into
However, as the operating frequency becomes higher, for example 10GH2 or higher, the G, A
, the inherent characteristics of FET elements, such as gain, noise figure, and their band characteristics.

Sexuality is damaged. For this reason, G, A, and FET elements are being directly incorporated into high-frequency circuits. However, under such conditions of use, it is difficult to completely isolate the G, A, and FET elements from the surrounding atmosphere;
It is difficult to guarantee high reliability of a microwave semiconductor device in which an ET element is directly incorporated into a high frequency circuit. Therefore, even in the frequency band of 10GH2 or higher, G, A, FE
A container that does not significantly impair the characteristics of the T element has been proposed. As shown in FIG. 1, this container has a structure in which a hermetic sealing metal cap 1 is used as a ground terminal to reduce ground inductance as much as possible. That is, G, A, and FET elements are stored in a container 3, and a brazing material 2 such as gold-tin is used.
The metal cap 1 is adhesively fixed to the metallized layer 6 for airtight sealing to achieve airtight sealing. In addition, external leads 4 and 5
are input/output terminals, and are used as gate and drain terminals, respectively. Since the hermetic sealing metallized layer 6 is electrically connected to the grounding metallized part 8 through the metallized part 7 formed on the inner wall of the ceramic container 3, the metal cap 1 serves as a ground terminal, for example, a source terminal.
Further, the leads 4 and 5 are connected to metallized parts 20 and 21 which are connected to internal input/output metallized parts 9 and 10 formed in the ceramic container 3. This container has an input/output metallized portion 9 formed by penetrating the inside of the ceramic container 3.
, 10, two ceramic plates (hereinafter,
(abbreviated as CP) 11 and 12 are bonded together and fired at high temperature. This is commonly referred to as a laminate package. A method of manufacturing this laminated package will be explained with reference to FIG.

First, as shown in figure a, for example, the area of 5 h x mark - has a thickness of O and 38 rfr! Prepare CPII made of n alumina, and add 8 source metallizations and 1 drain metallization layer to it.
0 and gate metallization 9 are formed by thinly printing a metal such as tungsten. Next, as shown in Figure b, CP
A CP12 having the same shape as 11 is prepared and punched out into a circular shape to form a portion 13 that can be the internal volume of the container.

In this case, the punched circular portions 13 are formed at the same pitch as the pattern printed on the CPll, that is, the source, drain, and gate metallized portions 8, 10, and 9. Next, as shown in FIG. 3c, metallization 6 for airtight sealing is printed. Next, CPll and CP12 are aligned as shown in d of the figure, and the two are bonded together using a high temperature press.

Next, as shown in FIG.
In order to conduct the metallized portion 6 of the CP12, a metal such as tungsten is deposited on the inner surface of the CP12 and above the metallized portion 8 of the CP11, generally using a thin brush or the like, to form the metalized portion 7. After this, it is fired and C
Pll and CPl2 are integrated to ensure airtightness.
Next, CPll and l2 are cut to a predetermined size, and metallized parts 20 and 21 for attaching external leads 4 and 5 are formed on the outer side surface of CPll so as to be in contact with metallized parts 9 and 10. Then, a laminate type package is completed by attaching external leads 4 and 5 such as cover to the metallized parts 20 and 21 using, for example, a silver-copper solder. As described above, the most problematic aspect of this manufacturing method lies in the step of forming the inner side metallization 7.

That is, since the metallized portion 7 is formed manually with a brush or the like, the width 1 of the metallized portion 7 is different for each package. The width 1 of this internal metallization 7 greatly affects the grounding inductance. That is, if the width 1 is wide, the ground inductance is small, and if the width 1 is narrow, the ground inductance is large. For this reason, the grounding inductance of individual packages varies widely. This shows that the ground inductance of GaAs FETs made using such a case always differs from one FET to another. Therefore, when this FET is included in a high frequency circuit for selection, the matching circuit of the input/output high frequency circuit is not fixed and it is necessary to always match each FET. This matching process requires a great deal of time and patience, which increases the manufacturing cost of the FET and often makes it impossible to accurately evaluate performance. The purpose of the present invention is to eliminate the above-mentioned drawbacks,
GaAs FETs can reduce the manufacturing cost of GaAaFETs, enable accurate evaluation, and exhibit certain unique characteristics.
An object of the present invention is to provide a method for manufacturing a container for obtaining an FET.

The method of the present invention is characterized in that metal is deposited on another surface of the insulating substrate that intersects with one principal surface by suction or pressing, thereby forming a metallized layer on the other surface.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a manufacturing process diagram showing an embodiment of the present invention.

First, as shown in figure a, the thickness is 0.387077! So 5−×
Prepare an alumina CP2l with an area of 5C#0n, and place metallization 22 for the source, metallization 23 for the drain, and metallization 24 for the gate in the corners with a side length r, for example 2, using a thin layer of metal such as tungsten. Print and form. Here, the metallized parts 22, 23, and 24 are separated and independent patterns, and the length m1 of the source metallized part 22 and the distance between the gate and drain metallized parts are each designed to be 1.5TnIn11rA. On the other hand, CP2l, which has the same shape as CP2O, is punched out to remove the rectangular part M3, forming a space 25 that becomes part of the internal volume of the package, as shown in Figure b.At this time, Side M3 is M.>M3>M4> and M3
m1=1.5
For example, in the case of wun, M3=1.2T! Take it like n.
Therefore, when CP2O and CP2l are superimposed, CP2l
The four short sides of the space 25 are located above the metallized portion 1 of CP2O. Also, the length of the side toe should be about the same as M2, but since the law mainly determines the value of grounding inductance, it is important to make it as large as possible. Next, as shown in FIG.
form. The inner surface metallized portion 27 is formed by a method according to the present invention, which will be described in detail with reference to FIG. FIGS. 4A and 4B show a plan view and a sectional view, respectively, during printing.

The CP2l is placed on a pedestal 28 made of a material that can be brought into close contact with the CP2l, such as a com. This pedestal 28 has C
Slightly smaller than the rectangular hole 25 of P2l, for example 0.1~
A hole 29 that is approximately 0.2 in size is formed. And C.P.
Hole 29 of pedestal 28 from the side opposite to the side that is in close contact with 2l.
Air is taken in using an evacuation device such as a rotary pump, for example. When so-called screen printing is performed on metal such as tungsten while the air is being sucked, the liquid tungsten is sucked into the hole 29 of the pedestal 28, and flows to the inner surface as well as the surface of the CP 2l, forming metallized portions 26 and 27. Ru. In this screen printing, a mask with a pattern of a predetermined shape is placed on the CP, and tungsten in a liquid mixed with an organic solvent is poured onto the mask. At that time, the tungsten on the pattern is transferred onto the CP. It oozes out and a metallized layer is formed. Therefore, a large amount of tungsten oozes out due to the intake air by the exhaust device, and a metallized layer is formed on the inner surface of the CP2l. At this time, since the hole 29 of the pedestal 28 is slightly larger than the hole 25 of the CP2l, metallization is formed immediately around the rectangular hole 25 on the surface of the CP2l opposite to the metallized surface. The CP 2l formed by this method is punched out so that at least the metallized portion 27 of the short side of the rectangular hole 25 remains as shown in FIG. 3d.

This is to prevent the gate/drain metallized parts 24, 23 and the metallized part 27 from coming into contact with each other. In order to satisfy this condition, the sides M5 and M6 of a newly punched rectangle have the following rules: <M3, r~> pallet, j>M2 and M.
Just set the size so that >j, for example, turtle = 1.1T! Rlrl. ．． The order is nl6=1.5. This punching process removes most of the longer sides of the rectangle of CP2l, so the remaining portion of the inner surface metallization 27 is the two shorter sides of the rectangle and a small portion of the longer side.
05? It will be about. Therefore, the width of the inner metallization 7, which affects the grounding inductance, is the width of the rectangular hole 25. Short side M
It is mostly determined by the length of 6. The value of the grounding inductance created in this way can be suppressed to within ±5%. Next, as shown in figure e, the processed CP2O and 2
1 and 2 are aligned and overlapped so that the source metallization 22 is at the center of the CP 2l, and they are brought into close contact with each other using a high-temperature press.

Thereafter, the container is baked to make it completely airtight, and then it is divided into individual containers using a cutter or the like into a predetermined size, that is, the size of a tortoise. Next, F, f in the same figure
As shown in the plan view and cross-sectional view in ``, CP2O is connected to the drain and gate metallized parts 23 and 24.
Metallization 30, 31 is applied to the external side surface of the

Thereafter, as shown in plan and cross-sectional views in FIGS. G and G', external leads 32 and 33 made of, for example, a cover are fixed to the external metallized portions 30 and 31 using, for example, silver-copper brazing or the like. Next, Ni and Au plating are performed in sequence, followed by sintering to complete the package. In this way, according to this method, when the inner surface metallized portion 27 of CP2l is applied, C.
Since this is done at the same time as forming the metallized portion 26 on one side of P2l, the manufacturing cost of the package can be reduced by eliminating work such as hand-painting. Furthermore, by punching the CP2l twice, the inner metallized portion 27 can be formed to have a constant width, so the ground inductance can be made very uniform, and the high frequency characteristics of the package can be made uniform. 5A, b and c are plan views showing other semiconductor containers formed according to the present invention, X-X''
FIG.

This container has a source terminal connected to a copper stud 51 made of copper, and a grounding metallized part 52.
A metal cap (not shown) is connected to the terminal to ground it. An inner metallized portion 53 is required to connect this metal cap and the copper stud 51, and if this is formed by the method shown in FIG. 4 and FIG. Become. Further, this container is also composed of two CPs 54 and 55. Note that the metallized parts 56 and 57 are for a gate and a drain, respectively, and leads 58 and 59 are connected to them. As described above, according to the present invention, it is possible to manufacture a container in which manufacturing costs are reduced, the characteristics of the element are sufficiently obtained, and the variation thereof is extremely reduced.

It goes without saying that the present invention is not limited to the above embodiments. That is, the material, thickness, and size of the CP and the material of the soldering material are not limited to these. Further, the punched shape of the CP can be arbitrarily selected, for example, circular as in the conventional case. Furthermore, the same method can be used when forming metallization on a container made of three or more CP sheets or on the inner surface of a single insulating substrate. Further, although the inner surface metallization in FIG. 4 was performed by suction, it may also be formed by pressing from above a mask.

Furthermore, the size of the hole 29 in the base 28 is made larger than the hole 25 in the CP2l, but this is because the metallized portion 22 of the CP2O
Therefore, if it is not necessary to form it all the way to the end of the back surface, the same size may be used.

[Brief explanation of the drawing]

Figure 1 shows a conventional GaAsFET container, in particular, a is a perspective view, b is a plan view with the cap 1 removed, and c
is a sectional view taken along line X-X'' of b.

Claims (1)

[Claims] 1. Metallization of an insulating substrate, characterized by attaching metal to another surface intersecting with one main surface of the insulating substrate by suction or pressing, thereby forming a metalized layer on the other surface. Layer formation method.