JPH0578160B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a dielectric film, and in particular to a method of selectively and uniformly sputtering a transparent conductive film so as to cover it on a substrate on which a transparent conductive film is formed. The present invention relates to a method for forming a dielectric film.

Prior Art For example, in a thin film EL display element, a thin film EL display element is produced by placing a first dielectric film 3 on a gas substrate 2 on which a striped transparent electrode group 1 is formed as shown in FIG.
(Electro Luminescence) A structure in which a light emitting layer 4 is formed, a second dielectric film 5 is further formed on it, and a striped back electrode group 6 is provided on it so as to be perpendicular to the transparent electrode group 1. It's getting old. That is, the transparent electrode group is covered with a dielectric film except for at least the electrode extraction portions at the ends.

The first dielectric film 3 has conventionally been manufactured by a high frequency magnetron sputtering method.

After attaching a dielectric film to a glass substrate on which a transparent conductive film is formed, when observing the infrared transmitting spectrum inside the substrate, it is divided into a part that transmits light with a wavelength of around 2 μm and a part that does not. This difference in infrared transmission spectrum occurs when the dielectric film is formed by sputtering. At this time, conductivity also deteriorates. This phenomenon often occurs particularly when an oxide dielectric film is used as the first dielectric film. This non-uniformity appears as non-uniformity in brightness in the EL display element, and is a fatal defect in the display.

In order to prevent this non-uniformity, after forming a dielectric film by sputtering, heat treatment is performed in air or vacuum to make the resistance value of the transparent conductive film constant and the infrared spectral characteristics to be uniform.

Problems to be Solved by the Invention However, this heat treatment has little effect unless it is performed at a temperature higher than the substrate temperature during sputtering, and the withstand voltage characteristics of the dielectric film after the heat treatment deteriorates and the number of defects increases. Also, using this process reduces the brightness of the EL display element.

If a dielectric film is simply formed on a transparent conductive film by sputtering and then subjected to heat treatment in air or vacuum, the performance of the dielectric film will only deteriorate, which is the case with EL display elements. In the end,
This leads to a decrease in brightness.

The present invention has been made in view of the above points, and an object of the present invention is to provide a dielectric film manufacturing method for manufacturing a homogeneous and high-performance dielectric film when forming a dielectric film on a dielectric conductive film by sputtering. The purpose is

Means to Solve the Problem After forming an oxide dielectric film by sputtering on a substrate on which an electrode of a transparent conductive film is formed, the substrate on which the oxide dielectric film is formed is removed during the formation of the oxide dielectric film. Heat treatment is performed in a plasma containing oxygen at a temperature higher than the substrate temperature for a certain period of time.

Effect When an oxide dielectric film is formed on a transparent electrode by sputtering, the partial deterioration of the transparent conductive film can be eliminated by the action of plasma and heat by performing high temperature heat treatment in oxygen-containing plasma. hand,
It becomes possible to manufacture a dielectric film that is homogeneous over the entire area and has good dielectric properties.

Embodiment FIG. 1 is a diagram showing an embodiment of the dielectric film manufacturing method of the present invention. A magnet 9 was attached to the back side of the target 8, and high frequency magnetron sputtering was performed using a high frequency power source. A ceramic target containing strontium titanate, which is a perovskite oxide dielectric, as a main component was used as the target. As a result, sputter plasma 7 was generated, and the dielectric film was formed while heating the substrate 11 with the heater 14 for heating the substrate. At this time
From the gas inlet of Ar13 and O ₂ 12 respectively.
Flow rates of 25 SCCM and 80 SCCM were injected, and the gas pressure was controlled to 5 mTorr using the oil diffusion pump 10.
The substrate temperature at this time was 450°C. As shown in the figure, the substrate 11 moves within the vacuum chamber 16 in the direction of the arrow, and moves from the dielectric film deposition area to the oxygen-containing plasma heat treatment area, which is partitioned by the adhesion prevention plate 17. However, this plasma used sputter plasma during film formation. The substrate 11 with the dielectric film was then heated to 550° C. using the heat treatment heater 15 to process it.

As a result, when an indium tin oxide (ITO) film was used as a transparent conductive film, and a strontium titanate-based oxide film was formed as a dielectric film using the above process, the resistivity was 10 times higher than that of ITO. became homogeneous over the entire board.

Furthermore, when an EL display element shown in FIG. 2 was formed using this substrate, it was found that it had a uniform luminance of 30 ft-L when driven with a 60 Hz pulse wave. It also had a withstand voltage of over 250V. The membrane configuration at this time is as follows.

The transparent conductive film on the stripe was an ITO film, the first dielectric film was an oxide dielectric film containing strontium titanate as a main component, formed by the manufacturing method of the present invention, and the E-emitting layer was an ITO film. , Mn in ZnS
A barium tantalate film was used as the second dielectric film, and an aluminum evaporated film was used as the back electrode group.

As described above, in order to eliminate the inconsistencies in the properties of the transparent conductive film that appear after the dielectric film is formed by sputtering, and also to prevent the performance of the dielectric film from deteriorating, heat treatment in plasma containing oxygen is necessary. It was effective.

As shown in the above example, if an in-line sputtering device is used, the effects of the present invention can be obtained relatively easily by using sputtering plasma as oxygen-containing plasma without creating a new plasma heat treatment area. .

When the present invention was carried out using yttrium oxide or barium tantalate as a sputter target, similar effects to those of the present invention described above were obtained.

Effects of the Invention As described above, according to the present invention, it is possible to eliminate the non-uniformity of film quality that occurs when forming an oxide dielectric film of a transparent conductive film by an extremely simple method, and to form a homogeneous oxide dielectric film. This dielectric film manufacturing method can provide a substrate with a transparent conductive film and is extremely useful for manufacturing EL display devices, for example.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a method for manufacturing a dielectric film in one embodiment of the present invention, and FIG. 2 is a cross-sectional view of a thin film EL display element. 7...Spatsuta plasma, 8...Target,
11...Substrate, 12... _O2 gas inlet, 13...
...Ar gas inlet, 14...Heater for heating the substrate,
15...heater for heat treatment, 17...adhesion prevention plate.

Claims (1)

[Claims] 1. In a method of forming an oxide dielectric film by sputtering on a substrate on which an electrode of a transparent conductive film is formed, after forming the oxide dielectric film by the sputtering, A method for manufacturing a dielectric film, characterized in that the substrate on which the dielectric film is formed is subjected to heat treatment in plasma containing oxygen at a temperature higher than the substrate temperature at the time of forming the oxide dielectric film. 2. The method for manufacturing a dielectric film according to claim 1, characterized in that an indium tin oxide thin film is used as the transparent conductive film. 3. The method for manufacturing a dielectric film according to claim 1, characterized in that a perovskite oxide is used as a target for forming the oxide dielectric film. 4. The method for manufacturing a dielectric film according to claim 1, characterized in that a mixed gas of argon and oxygen is used as the sputtering gas. 5. The method for manufacturing a dielectric film according to claim 1 or 4, wherein the atmosphere of the heat treatment in plasma containing oxygen is a plasma state of a mixed gas of argon and oxygen.