DE1765993C3 - Process for the manufacture of electrical circuit elements - Google Patents

Description

The invention relates to a method for producing electrical circuit elements, wherein in one A predetermined material from the gas phase onto predetermined areas of the surface of a chamber Chamber arranged substrate deposited using a radiation source and a mask will.

From DT-AS 1 233 694, a method for producing one with a base metal is intermetallic Connected aluminum surface layer known, with aluminum from the gas phase of organometallic milk Aluminum compounds are deposited on heated surfaces and thermally converted. That known method does not allow the production of a sharply delimited temperature profile on the surface, on which the aluminum is knocked down great, which is why the knocked down material also wedged has a precise and sharp contour.

From GB-PS 864 869 is a method for the production known from printed circuit boards using a radiation source and a mask. However, the radiation source consists of infrared lamps, which are covered by an aluminum foil. A gelatine layer is used as a layer of gelatin ■ arranged on a band running over the aluminum foil is. A film is arranged over the gelatin mask, on which, according to the shape of the Mask precipitates the desired material from the vapor phase.

The mask and the lamps are arranged inside the precipitation chamber, which leads to pollution

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tongues of these parts. It is also not possible with this method, a sharply delimited To obtain temperature profile on the free surface of the substrate on which the material will be deposited should there by the arrangement of an aluminum foil and a tape between the radiation source and the Mask no actual irradiation but only a heating of the areas on which the material takes place is knocked down.

The invention is therefore based on the object of specifying a method of the type mentioned above, which it enables a deposit layer with a predetermined shape and shape to be formed on the surface of the substrate to produce a sharp contour.

According to the invention this is achieved in that the predetermined areas of the surface of the Substrate in the presence of the gaseous material by a laser arranged outside the chamber irradiated with the interposition of a hologram also arranged outside the chamber and be heated to the precipitation temperature.

The invention makes it possible to have a sharply delimited temperature profile on the surface of the substrate generate, whereby it is achieved that the shape of the deposited material is an exact ur.d has a sharp contour.

Appropriately, a pulsed ruby laser is used as the laser, as well as a hologram, the phase or is variable in amplitude.

Preferably the required amount of radiant energy is obtained by a single pulse of the laser Applied., the substrate before the irradiation to a temperature below the precipitation temperature is heated. The radiation source can be in the infrared or in the visible red range of the spectrum.

An example embodiment of the invention is shown below with reference to the single figure of FIG Drawing explained, which shows schematically in section a device for performing the method.

In the illustrated and described embodiment, for example, a number of thin film resistor elements are used from a gaseous atmosphere containing carbon, e.g. B. benzene vapor at a pressure of about 1 atmosphere, on a Depressed aluminum base.

In the figure, a substrate 10 is on a base plate

11 arranged in a hermetically sealed chamber 12. The substrate is at some distance from the mouth of a tube 13 through which Benzene vapor into the chamber through a control valve 14

12 is initiated. The chamber can be opened by pumping off the gas atmosphere via a pipe 15 and a valve 16 to be evacuated.

Outside the chamber 12 are a pulsed ruby laser 17 and a phase changeable hologram 18 arranged, the radiation of the laser through the hologram 18 and through a window 20 into the chamber 12 is directed. The laser 17 and the hologram 18 are arranged so that only certain areas the surface 21 of the substrate 10 are irradiated. The irradiation increases the temperature in the irradiated Areas of the surface 21 strongly, so that a temperature profile is formed which is approximately that of the Irradiation pattern corresponds. The irradiated areas are heated to a temperature of at least 800 ° C heated, the benzene splitting into its components at this temperature, so that carbon

precipitates in a very pure form on the irradiated areas. For example, the carbon in finer thickness of 100 angstroms per microsecond Only knocked down by a laser pulse.

It was found that a laser with an emission which allows a radiation energy of 10OMw / cm ^{2 to} fall on a substrate causes a temperature increase of about 1000 ° C. in a period of about 50 nanoseconds on the irradiated surface has the consequence, ie a duration which corresponds to the duration of a single pulse of the laser.

Via a control valve 22 and the pipe 13 can be in the Chamber 12 argon can be introduced, if the normal energy emission of the laser, the benzene pressure is higher in the chamber than required to deposit a layer of carbon of the desired thickness is.

The pattern of the phase-changeable hologram is produced by treating a transparent gelatin plate, which is in the form of a conventional spectro- »Copy plate with a photosensitive emulsion is formed on a surface.

A picture of the desired hologram pattern is reproduced, the image being reproduced by changes in the silver coating is generated on the plate. The plate is then developed and fixed in a known manner. Afterward the silver is dissolved out by etching, creating adjacent parts of the emulsion on the plate in one shrinkage proportional to the amount of silver removed, creating the desired Relief pattern is created on the plate.

A phase varying hologram requires a phase shift of 180 ° between the light that by a raised part and the light that is transmitted through a deep part of the relief pattern. For the light from a ruby laser with a wavelength of 4257 Angstroms, there is a relief pattern with a uniform step height of essentially 2128 angstroms required.

Thin film resistors made by the method described above a uniform thickness and they are reproducible within ± 5%. There can be layers with produce extremely sharp contours. This is how the temperature rises in the case of a substrate made of aluminum after a laser pulse at a distance of 1 micron from the edge of the irradiation pattern a time corresponding to 10 pulses, on the order of 10 ° C.

The deposited layers are then separated from the substrate, e.g. B. by scoring the base with a sharp tool and scraping off the layer in conjunction with suction devices.

Instead of a phase-changeable hologram, an amplitude-changeable hologram can also be used be used. The substrate is brought to a temperature just below the required before irradiation Precipitation temperature heated by benzene, z. B. to a temperature of 600 ° C.

Layers of carbon can also consist of an atmosphere of methane, toluene, xylene, or acetylene be prepared, the precipitation temperatures are different and the temperature for the Precipitation of carbon from methane z. B. is on the order of 1000 ° C.

It can also be deposited several materials at the same time, z. B. can from a gas atmosphere, which consists of benzene and boron trichloride, carbon resistors doped with boron are produced, the z. B. may contain 5% boron. In addition, insulating or dielectric layers can be deposited made of aluminum from an atmosphere of aluminum chloride in the presence of oxygen will.

Furthermore, semiconductor materials and / or impurities, which determine the conductivity type, are deposited, e.g. B. silicon from a mixture of silicon tetrachloride and hydrogen or germanium from a gaseous atmosphere of Dimetyigermanium. Or it can e.g. B. boron can be deposited on a silicon wafer, e.g. B. off an atmosphere of boron trichloride or borohydride. Phosphorus can be extracted from an atmosphere containing phosphine contains, gallium from gallium chloride, aluminum from aluminum chloride and arsenic from arsine and antimony be precipitated from antimony hydrogen.

Catalysts can be added to the gas atmosphere in order to facilitate the precipitation process or increase the precipitation rate <.u. Further In addition, a line pattern can be produced by selective application of conductive material, z. B. Nickel conductors from a nickel tetracarbonyl atmosphere.

By successive deposition of conductive material, dielectric material and again conductive material on a certain area of a substrate can e.g. B. capacitors or also Crossings of ladders are made.

However, the method is particularly suitable for the production of thin-film components of hybrid circuits.

1 sheet of drawings

Claims (5)

Claims: 1 1. Process for the manufacture of electrical Circuit elements, with a predetermined material from the gas phase to predetermined in a chamber Areas of the surface of a substrate arranged in the chamber using a radiation source and a mask is deposited, characterized in that the predetermined areas of the Surface of the substrate in the presence of the gaseous material through an outside of the Chamber arranged laser with the interposition of a also arranged outside the chamber Holograms are irradiated and heated to the precipitation temperature. 2. The method according to claim 1, characterized in that the laser is a pulsed ruby laser is used and that the hologram is variable in phase or amplitude. 3. The method according to claim 2, characterized in that the required amount of radiant energy is applied by a single pulse of the laser. 4. The method according to any one of the preceding claims, characterized in that the substrate is heated to a temperature below the precipitation temperature prior to irradiation. 5. The method according to any one of the preceding claims, characterized in that the radiation source emitted in the infrared or in the visible red part of the spectrum.