JPH01212751A - Method for manufacturing aluminum nitride transparent film - Google Patents

Abstract

PURPOSE:To easily manufacture a transparent AlN film having arbitrary transmissivity at high film-forming speed by implanting specific amounts of N ions in a thin Al film while vacuum-depositing the thin Al film onto a substrate and also holding the substrate at low temp. CONSTITUTION:In a vacuum chamber 1 held at the prescribed pressure by means of a vacuum pump, Al vapor 7 generated from an evaporation source 6 is vapor-deposited onto a substrate 3 attached to a holder 2 to form a thin Al film. Further, N ions from an ion source 4 are implanted in the above thin film under formation. The proper vapor deposition velocity of the above Al is 4-20Angstrom /S. Moreover, as the substrate 3, a glass sheet, a polyimide film, a silicon sheet, an Al sheet, a stainless steel sheet, etc., can be used. In the ion implantation method in the above vacuum vapor deposition method, N ions are simultaneously or intermittently applied in the ratio of approximately 1:1 to Al content. Simultaneously, the temp. of the substrate 3, at least in the thin film formation part, is held at <=100 deg.C. Further, by controlling the above temp., the light transmittance of thin film can be controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an aluminum nitride transparent film,
In particular, the present invention relates to a method for producing an aluminum nitride transparent film suitable for use as a mask material for X-ray lithography, for example, using a combination of vapor deposition and ion irradiation.

[Conventional technology]

The conventional aluminum nitride transparent film is disclosed in Japanese Patent Application Laid-Open No. 58-202.
Publication No. 2 and l0NIC5, April 1983 issue, P47
As described in ~52 etc., at the same time as irradiation with nitrogen ions accelerated to about 40 keV, 0.2 people//S ~ 0.8 Å/s
The method used was to deposit aluminum at a deposition rate of . However, according to the above-mentioned thin film formation method, the maximum thin film formation speed is 0°8 Å/s, and if the required film thickness is 1 μm, it takes 3.5 hours to form the film, which is too slow in terms of productivity. There was a problem that the film formation rate was slow. Furthermore, even though the film is transparent, no consideration has been given to a method for manufacturing the film with uniform transparency above a certain level.

[Problem to be solved by the invention]

With the above conventional technology, the transparency of the film has not been consistently studied, that is, the relationship between the irradiation ion current and the metal deposition rate and transparency is unclear, so it is unclear how transparent the film is. It was unknown. In addition, there was a practical problem in that the film formation rate of the aluminum nitride transparent film was low.

An object of the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a colorless and transparent aluminum nitride transparent film of a certain level or higher, which can be formed at high speed.

[Means to solve the problem]

In order to achieve the above object, the present invention deposits aluminum on a substrate using a vacuum evaporation method to form a thin film, and simultaneously or intermittently injects nitrogen ions into the thin film that is being formed using an ion implantation method. irradiate at a ratio of approximately 1:1 to the amount, and the temperature of the substrate is 100%.
It is to be kept below ℃. Here, the range of approximately 1:1 is preferably AQ/N=0.6 to 1.3.

When the deposition rate of aluminum on the substrate is set to 4 to 20 Å/s, the deposition rate increases, but this also increases the amount of nitrogen ion irradiation, which causes the temperature of the substrate to rise.
Although the transparency of film formation is a problem, by keeping the substrate temperature at 100° C. or lower using a cooling means, it is possible to increase the film formation rate and prevent a decrease in film transparency.

Substrate materials include glass plate, polyimide film,
A silicon plate, an aluminum plate or a stainless steel plate can be used.

[Effect]

AQN is generated by forming a thin film by vapor deposition of aluminum and implanting nitrogen ions into the thin film, but by setting the ratio of AM to N to approximately 1:1, for example, the proportion of AQ alone remaining in the film is reduced. Therefore, the transparency of the formed film can be increased to a certain level or higher.

At this time, the temperature of the substrate increases due to aluminum evaporation and nitrogen ion irradiation, but cooling means
The transparency of the film is maintained by maintaining the temperature below .degree.

When the deposition rate of aluminum on the substrate is set to 4 to 20 Å/s, the deposition rate is significantly increased.

〔Example〕

First, a brief explanation will be given. In the present invention, aluminum metal is evaporated from an evaporation source and deposited on a substrate, and simultaneously or intermittently irradiated with nitrogen ions. As the substrate, a glass plate, a polyimide film, a silicon plate, an aluminum plate, a stainless steel plate, etc. are used.

The point to note here is that in order to form a transparent aluminum nitride thin film, aluminum and nitrogen must be mixed at approximately 1
: 1 (AQ/N=0.6 to 1.3) and the temperature of the substrate must be maintained at 100° C. or lower.

When forming a film at a film forming rate of several Å/s or less, temperature rise does not pose a problem. However, in order to increase the film formation rate, it is necessary to irradiate nitrogen ions that match the aluminum evaporation rate, and in this case, heat generation occurs due to the ion irradiation. Therefore, consideration must be given to cooling the heat generated. In other words, when forming an aluminum nitride transparent film on a substrate by evaporating aluminum at a deposition rate of several Å/s to several tens of thousands of people from the viewpoint of productivity, a commensurate amount of heat is added due to the irradiation of nitrogen ions. The substrate should be cooled so that the temperature of the substrate can be maintained at 100° C. or less even when the temperature is low. In addition, when the temperature of the substrate is raised above 100℃,
This is not preferable because nitrogen atoms in the aluminum nitride film are desorbed and the light transmittance is impaired. That is, the upper limit of the film formation rate is to keep the stoichiometric ratio of aluminum and nitrogen at approximately 1:1,
In addition, when the substrate is cooled by a cooling means and nitrogen ions are irradiated, the aluminum evaporation temperature is 20 Å/s, which corresponds to the density of nitrogen ions that can be maintained at 100°C or less, and the lower limit is 4 Å/s from the viewpoint of productivity as described above. It is desirable that it is s or more. Therefore, the maximum deposition rate is 1.4 μm/h.
~7.2 μm/h.

It is clear that the vacuum evaporation method can also be achieved by any one of electron beam evaporation, ion beam sputtering, magnetron sputtering, resistance heating evaporation, or similar methods.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows an apparatus used in an embodiment of the method for producing an aluminum nitride transparent film of the present invention. FIG. 2 shows the light transmission characteristics of an aluminum nitride transparent film according to an embodiment of the present invention.6 FIG. 3 shows an example of the X-ray diffraction results of an aluminum nitride transparent film according to an embodiment of the present invention.

As shown in FIG. 1, with respect to a substrate 3 attached to a water-cooled rotary holder 2 in an evacuated vacuum chamber 1,
First, 5 ions generated from the ion source 4 are accelerated at, for example, 5 kV.
Sputtering and cleaning are performed by irradiating with a nitrogen ion beam 5 of 0 mA. Next, the nitrogen ion beam 5 was irradiated to form a thin film of aluminum nitride on the substrate 3 while evaporating aluminum vapor 7 from the evaporation source 6 at a deposition rate of, for example, several Å/s to several tens of Å/s. The ion source 4 and vacuum chamber 1 were prepared in advance with a diameter of 2×10”
Raise the degree of vacuum to r r and keep it at 1X10-' even during thin film formation.
The vacuum level was maintained at Torr.

FIG. 2 shows the light transmission characteristics of an aluminum nitride thin film formed on a glass substrate. FIG. 2(a) shows the light transmittance of each aluminum nitride thin film formed by changing the aluminum evaporation rate. In the figure, the transmittance of a glass substrate on which no thin film is formed is also shown for comparison. Figure 2(b) is a plot of the relationship between light transmittance and aluminum evaporation rate in the visible region of the above data, ranging from several Å/s to several 1
This shows that a permeable membrane is formed when several people are present.

As shown by the X-ray diffraction results in FIG. 3, only AQN peaks are detected in thin films where the aluminum deposition rate is 12 Å/s or 13 Å/s, indicating that the thin films have good permeability.

However, in a thin film where the aluminum deposition rate was 14 Å/s, not only the AQN peak but also the AR peak was detected. This is consistent with having the translucency shown in FIG.

Next, in order to increase the deposition rate of aluminum nitride,
The deposition rate of aluminum was increased and the density of nitrogen ion irradiation was increased accordingly.

As a result, the characteristics were shifted to the right as shown by the broken line in FIG. 2(b). Then, the temperature of the substrate 3 is 10
It has been experimentally confirmed that if the temperature is kept below 0°C, it exhibits transparency, and when the temperature rises above 110°C, the nitrogen atoms within the film are eliminated and the film changes from translucent to opaque. Here, in order to keep the temperature of the substrate 3 below 100°C, it is relatively easy to use aluminum plates, stainless steel plates, etc., but with glass plates, silicon plates, polyimide films, etc., special care must be taken when cooling the substrate 3 to prevent heat generation due to ion irradiation. The sample was then cooled using a water-cooled rotary holder 2 with a thermally conductive paste interposed therebetween. therefore.

The upper limit of the film forming rate can be further increased by using a paste that has a more efficient cooling effect or by improving the cooling means.

As described above, we have discovered that the light transmittance of the thin film can be changed by controlling the temperature of the substrate when forming an aluminum nitride thin film on the substrate using simultaneous aluminum evaporation and nitrogen ion irradiation. Taking advantage of this, the film formation rate is relatively high and transparency is excellent. A method for forming a film that is easy to manufacture has been realized.

〔Effect of the invention〕

According to the method for producing an aluminum nitride transparent film of the present invention,
The film formation speed is 1 to 2 orders of magnitude faster than conventional methods.
Furthermore, it becomes possible to control the transmittance of the membrane, and a membrane with any desired transmittance can be easily produced. This has the effect of greatly increasing industrial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for forming an aluminum nitride transparent film in an embodiment of the present invention, and FIGS. 2(a) and 2(b) are characteristics showing the light transmittance of the aluminum nitride transparent film in an embodiment of the present invention. 3 are characteristic diagrams showing the results of X-ray diffraction of an aluminum nitride transparent film in one embodiment of the present invention. 1... Vacuum chamber, 2... Holder, 3...
Substrate, 4... Ion source, 5... Ion beam, 6.
...Evaporation source, 7...Metal vapor. Figure 1 1--Ichimoku Chasono\”-2--Bo, Ruder 3-
-A Certain Rebellion 4- Ion Ring 5- Ion Beam 6- Temple Quantang 7-/'f;: Feng Jiaoqi Diagram 2 (al - (b)

Claims (1)

[Claims] 1. While forming a thin aluminum film on a substrate by vacuum evaporation, nitrogen ions are added to the thin film being formed by ion implantation at a rate of about 1:1 for the amount of aluminum.
1. A method for producing an aluminum nitride transparent film, which comprises simultaneously or intermittently irradiating the substrate at a rate of 1:1 and maintaining the temperature of at least the thin film forming portion of the substrate at 100° C. or lower. 2. The deposition rate of aluminum on the substrate is 4 to 20 Å/s
The method for producing an aluminum nitride transparent film according to claim 1. 3. The method for producing an aluminum nitride transparent film according to claim 1 or 2, wherein the substrate is any one of a glass plate, a polyimide film, a silicon plate, an aluminum plate, or a stainless steel plate.