DE1464296B2 - PROCESS FOR ETCHING A SEMI-CONDUCTOR COMPONENT - Google Patents

Description

1 2

The invention relates to a method of etching. The alloying takes place z. B. at a

of a semiconductor component at which one temperature of 780 ° C for 3 minutes. To

Surface side of the semiconductor body between two of the cooling occurs under the electrode 3 one

Electrodes an etch-resistant masking agent on- segregated layer 5 of the η-type, whereby the

brought and the electrodes surrounding the, not 5 electrode 3 an ohmic contact with the

masked surface is etched. Layer 2 produces, while under the electrode 4

It is known that the amount of masking agent creates an aluminum-containing segregated layer,

to be attached between the electrodes by making a rectifier contact with layer 2

the semiconductor body with the electrodes in one manufactures (see. Fig. 2). Then the lower surface of the

Masking agent, e.g. varnish, is dipped and that ίο body 1 is removed by etching and the body is

finally, after the paint has dried, the. by means of an indium layer 7 on one made of nickel

Body attached with the help of a solvent for the paint existing carrier 8 (Fig. 3).

is cleaned by spraying in such a way that this lacquer is 1 in length and width of the body

only on the part lying between the electrodes z. B. 3 mm, the thickness is 100 μπι. The width of the

the surface of the {body remains. This 15 covered by the electrodes 3 and 4 body part

The method thus requires two processing steps. B. for both electrodes 100 μπι, while

namely, dipping and cleaning through the uncovered part between these electrodes one

Syringes. The latter processing step must have a width of 80 μΐη,

follow closely. ■ - ■ By the way, the composition of this training

The invention aims, among other things, to make an input material not of essential importance; it

More complex method to achieve this goal, however, it is important that the surface portion of the

create. The invention is based on the knowledge of the body 1 surrounding the electrodes 3 and 4

reasons that electrical. Leads, sometimes the exception of the one lying between these electrodes

after, but in most cases before, the part is etched away.

of the masking agent on the electrodes. For this purpose, as shown in FIGS. 3 and 5

are brought, in the last-mentioned case shown, two side by side consisting of nickel

For the masking agent, leads 11 and 12 on electrodes 3 and 4 are used

can. soldered on. The leads here have the form of

According to the invention, the electrodes are made with wires which diverge slightly upwards. Between

two approximately parallel leads are connected and these wires are now inserted by means of a needle

between these feed lines a small amount smaller from a solution of nitrocellulose in

a masking agent applied in such a way that amyl acetate of existing drops 14 are applied,

that the masking agent along the supply lines to Under the influence of gravity and / or as a result

flows through the electrodes and the surface part of the surface tension effect of the liquid

Semiconductor body between these electrodes 35 speed between the wires moves this drop

covered. 14 in the direction of electrodes 3 and 4 until he has a

Preferably, the mutually tensile part of the surface of the body 1 converge between the

turned sides of the leads in the direction of electrodes covered (see Fig. 5). At this point lets

the electrodes. These pages can also be used to dry the masking agent. j

lie parallel to each other. 4 ° After the in F i g. 6 consist of the I

The invention is described below with reference to a supply line from the two legs 21 and 22 j

the embodiment shown in the drawing of a fork plate 23. The drop 24 is otherwise;

explained. in the same manner as in FIGS. 4 and 5 A

Figures 1 to 3 show three stages of manufacture of the device shown attached. v!

of a semiconductor device shown schematically in section. In the case of the FIG. 7 shown are the

body with two adjacent electrodes 31 and 32 strip-shaped, and the supply ^;

trodden; Lines consist of nickel strips 33 and 34 with

F i g. 4 to 7 show schematically the application of a width of 500 μm and a thickness of

method of masking agent; 50μΐη. The masking agent is applied to the

.. F i g. Fig. 8 shows a device for removing one of the 50 facing sides of these strips, or

■ Part of a semiconducting surface by means of a, possibly on only one of these sides, attached,

electrolytic etching treatment; whereupon on the between electrodes 31 and 32 _:

Fig. 9 and 10 show in cross section two finished lying surface part of the body 1 drains where

Transistors. it is dried. The dried layer is through

All figures are given on a very large scale 55 35,

drawn. Then an arrangement produced in this way is

In all examples, the starting material is introduced into a bath 40 which consists of a 30%;

Body 1 composed of p-type germanium with a solution of potassium hydroxide in water

resistivity of 1 Ω / cm and (see Fig. 8), the plus terminal being a power source

which is connected to the carrier 8 by diffusion of antimony in an upper 60 41. The negative terminal

area part 2 to a depth of 5 μπι in which this power source is located in the bathroom \

η-type is converted (see Fig. 1) and connected to the cathode 42. The ones with the bath in Beruh- J

then two electrodes 3 and 4 are alloyed. The tion coming surface - of the body 1 will. ;

Alloyed material of the first electrode 3 now exists at least over the entire depth of penetration

from a lead with 2 percent by weight of antimony det- 65 diffusion layer 2 of the η type. The part

holding alloy, while the electrode 4 through between the electrodes 3 and 4 is thereby through

Alloy of the same material is obtained, a formed by the dried masking agent

the mask 44 also protected about 10 percent by weight of aluminum. Finally the mask

44 removed with the help of acetone. The final result is shown in FIG. 9 shown.

Although the example described above is based on an alloy diffusion transistor with side-by-side Electrodes (base 3 and emitter 4) relates and the invention is particularly applicable to use in the manufacture of such transistors, it can also be used in other semiconductor devices, where a semiconducting surface has to be masked between two electrodes, Find application. It is further noted that the invention can also be used when at a semiconductor arrangement three or more electrodes lie next to each other. F i g. 10 shows an example such an arrangement. This semiconductor arrangement, also an alloy diffusion transistor, makes a difference only thereby differing from the one shown in FIG. 9 arrangement that two base electrodes 3 are present are. The manufacturing processes for these two transistors are also only different in that at a small amount of masking material is applied to the transistor shown in FIG. 10 twice.

Claims (3)

Patent claims: 1. Method for etching a semiconductor component, in which on one surface side of the semiconductor body, an etch-resistant masking agent is applied between two electrodes and the unmasked surface surrounding the electrodes is etched thereby characterized in that the electrodes are connected to two approximately parallel leads and that between these leads a small amount of a masking agent in is applied in such a way that the masking agent along the leads to the electrodes flows and covers the surface part of the semiconductor body between these electrodes. 2. The method according to claim 1, characterized in that the facing each other Sides of the leads converge in the direction of the electrodes T. 3. The method according to claim 1 or 2, characterized in that the masking agent consists of a soluble varnish. 1 sheet of drawings