JPH03247763A - Formation of film - Google Patents

Abstract

PURPOSE:To stably form a film having desired properties at high yield, at the time of depositing a material on a substrate and forming a film, by supplying power to a film while the current and voltage properties of the film are monitored, generating heat by the electric resistance and executing annealing. CONSTITUTION:A vacuum tank 1 is exhausted into a prescribed degree of the vacuum, and an electrical conducting vapor-depositing material 3 (such as W) in a crucible 2 is heated by a heating source and is vacuum-evaporated. Next, when a shutter is opened, evaporated material atoms 20 reach a substrate 5 via the opening of a mask 8 to form a film 4 patterned into a desired shape. At this time, when the material atoms 20 gradually deposit on the substrate 5 and an electrode 6 embedded in the substrate 5 into a film thickness sufficient for forming an electric circuit, a power source 7 for power supply also provided with a monitoring capacity is operated to supply power while its current and voltage properties are monitored to generate heat on the patterned film, by which annealing is executed. In this way, film forming and annealing are simultaneously executed in a single vacuum tank 1, so that the film 4 having desired properties can stably be obtd. at high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film forming method, particularly to a film forming method for high temperature operating devices such as thin film heaters used at high temperatures.

[Prior art] Fig. 3 shows, for example, Metal Surface Technology Vol. 30, No. 5 (1979).
This is a configuration diagram of a general vacuum evaporation equipment shown in
Conventionally, film formation has been performed using such an apparatus. In the figure, (1) is a vacuum chamber, (2) is a crucible, (3) is a deposition material, (4) is a film, (5) is a substrate, (9) is a shutter, (10) is a film thickness meter, (11) is a ) is a heater for heating the substrate.

To form a film using this device, first, the inside of the vacuum chamber (1) is evacuated to about 10-6 Torr, and the vapor deposition material (3) placed in the crucible (2) is heated and evaporated to form a substrate (5). A film (4) is formed by depositing on top. At this time, the film thickness is monitored by a film thickness meter (10) placed near the substrate (5). Furthermore, it goes without saying that the shutter (9) is opened and closed during actual film formation. In addition, when the film is used in a high temperature state as in a high temperature operating device such as a thin film heater according to the present invention, the film is formed by heating the substrate (5) to 100 to 500° C. with the substrate heater (11). There are many things.

In this specification, the case of forming a thin film heater will be explained as an example.

FIG. 4 is a process diagram showing the manufacturing process of a conventional thin film heater. The film is formed as described above (A), and the formed film is patterned into a desired heater shape (B). After that, the film quality is stabilized by annealing (C). For example, in the case of a W film, the electrical resistivity is approximately 20 μΩc immediately after film formation.
Although the value is as high as about m, it can be refined to several μΩcm, which is close to the bulk value, by annealing at about 1000°C. Annealing is an extremely important process in order to obtain stable heater characteristics. Finally, appropriate wiring is applied to complete the thin film heater (D).

[Problems to be solved by the invention] However, in the conventional film forming method as described above,
The final objective of the film properties (the electrical resistance of the film in this thin film heater) is greatly influenced by the annealing process after film formation. That is, if the annealing temperature and holding time vary, the electrical resistance of the film will vary. Also,
Because it is a thin film, the overall volume of the patterned film varies considerably due to variations in film thickness and dimensions during patterning. As a result, even if the annealing conditions are made more precise and the variation in film resistivity is reduced,
The resistance value of 1-tal as a heater, which is determined by (resistivity) × (total length of patterned film) ÷ (cross-sectional area of patterned film), varies, resulting in variations in the characteristics of the heater. There is a problem that These heater characteristics are only revealed after the assembly is completed and a power supply/heat generation test is performed, making it impossible to provide feedback to processes such as film formation, buttering, and annealing, resulting in extremely poor yields. It was there.

The present invention has been made to solve the above-mentioned problems, and its object is to form a thin film with stable characteristics and high yield, which requires annealing to improve the film characteristics.

[Means for Solving the Problems] A film forming method of the present invention is a method of forming a film by evaporating and depositing a conductive vapor deposition material, and forming a film by subjecting the film to annealing to improve its properties. The above material is deposited to form a film, and the film is energized while monitoring the current/voltage characteristics of the film during or after the film formation, and heat is generated by the electrical resistance to perform annealing. be.

[Function] In the film forming method of the present invention, by monitoring the current/voltage characteristics of the film during annealing, it is possible to know, for example, the electrical properties (resistance value, heat generation properties) and rough film thickness of the film. , it is possible to stably obtain a film with desired characteristics at a high yield.

[Example] Hereinafter, a film forming method according to an example of the present invention will be described by taking the formation of a W film of a thin film heater as an example. FIG. 1 is an explanatory diagram showing the principle of a film forming method according to an embodiment of the present invention. In the figure, (1) is a vacuum chamber, (2) a crucible, (3) is a conductive vapor deposition material, in this case W, and (4) is a battened W.
(5) is an insulating substrate, (6) is an electrode, (7) is a power source for energization that also has a monitoring function, (8) is a mask for batting, and (9) is a shutter.

The basic film formation process is the same as the conventional method. That is, after the vacuum chamber (1) is evacuated to about 10-'' Torr, the vapor deposition material W (3) placed in the crucible (2) is evacuated using an appropriate heating source such as an electron beam (not shown). The temperature is raised to a temperature at which vapor deposition is possible (approximately 400° C. in the case of W, at which time the vapor pressure is approximately 1 Torr).

By opening the shutter (9), the evaporated W atoms reach the substrate (4) through the opening of the mask (8), forming a W film shaped into a desired shape.

FIG. 2 is an explanatory diagram schematically showing the state of W film formation according to this embodiment, and shows the requirements of the present invention.

The flying W atoms (20) are deposited on the substrate (5) and the electrode (6) embedded in the substrate (5). At the very early stage of film formation, the film is thin, its own resistance is high, and the electrical connection with the electrode is insufficient, so it cannot be used as a practical electrical circuit. When the film thickness reaches the μm order, which makes it possible to use it as a thin film heater, it functions sufficiently as an electric circuit. (Generally, below 100 Å, the deposited film takes on an island-like structure and the electrical resistance is extremely high.
It is known that the film becomes an electrical conductor at a film thickness of 0.000 μm or more. ) When the film thickness is sufficient to form an electric circuit, the current supply power source (7), which also has a monitoring function, is activated to flow current. The battened W film (4) has a sufficiently large resistance and generates heat compared to other parts of the circuit. For example, when a W film with a batten width of 2007 Jm, a film thickness of 3 μm, and a total length of 6 mm is formed on a sapphire substrate, heat is generated to about 1000° C. with an applied voltage of 15 V. As mentioned above, the electrical resistance of W changes from 20μΩcm to several μΩcm due to annealing.
It is possible to refine the material up to. At this time, since the resistance value of the film can be obtained by monitoring the current and voltage according to Ohm's law, it is possible to refine the film accurately to the target value and, in principle, with a yield of 100%.

Additionally, in the past, annealing was performed after the film formation process, but
In this example, annealing is performed during film formation using the resistance of the deposited film itself, which is formed through a reverse-bump mask.
Film formation and annealing can be performed simultaneously in one vacuum chamber.

In addition, in the above embodiment, an example was shown in which a new wiring is provided on the electrode (6), but even if the electrode and the wiring are integrated, the same effect as in the above embodiment can be obtained.

Further, as a secondary effect of the present invention, it is also possible to estimate the film thickness by back calculating from the resistance value of the film.

Furthermore, although W is shown in the above embodiment as a conductive vapor deposition material according to the present invention, high melting point metals such as Ta and Re, or conductive ceramics such as TiC and TiN can be used, and the same effects as in the above embodiments can be obtained. play.

Insulating ceramics such as 5i02 and A9203 are used as the substrate material.

[Effects of the Invention] As described above, the present invention provides a method for forming a film by evaporating and depositing a conductive vapor deposition material, and then annealing the film to improve its characteristics. At the same time as depositing the material and forming the film, the current and voltage characteristics of the film are monitored during and after the film formation, and the film is energized to generate heat due to its electrical resistance and annealed. Electrical properties (resistance value, heat generation properties) and film thickness can be roughly controlled, and a film with desired properties can be stably obtained at a high yield.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of a film forming method according to an embodiment of the present invention, FIG. 2 is an explanatory diagram schematically showing the state of film formation, and FIG. The configuration diagram and FIG. 4 are process diagrams showing a conventional film forming method. In the figure, (3) is a conductive vapor deposition material, (4) is a film, (
5) is an insulating substrate, (6) is an electrode, and (7) is an energizing power source that also has a monitoring function. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A method in which a conductive vapor deposition material is evaporated in a vacuum atmosphere, the material is deposited on an insulating substrate to form a film, and the film is annealed to improve its characteristics to form a film. is deposited to form a film, and current is applied to the film while monitoring the current/voltage characteristics of the film during or after the film formation, and heat is generated by the electrical resistance to perform annealing. Film formation method.