JPS63203760A - Method and device for forming inorganic film to glass substrate surface - Google Patents

Abstract

PURPOSE:To uniformly form a high-hardness inorg. film on a glass substrate surface having a large area by evaporating an inorg. materials by an arc discharge and depositing the vapor thereof by evaporation on the substrate while moving the glass substrate horizontally in a vacuum chamber. CONSTITUTION:The inside of the vacuum chamber is maintained under 5X10<-4>-1X10<-2>Torr and the glass substrate 2 is horizontally and linearly moved so as to be passed under an arc vapor deposition source 1 as a vapor source for forming the inorg. film disposed above the substrate to form the inorg. film on the substrate by vapor deposition. A rear side electrode plate 3 is disposed on the rear side of the substrate 2 so that the vapor particles evaporated by the arc discharge are ion-accelerated. The inorg. film consists of an inorg. material contg. at least one kind among oxide, nitride, carbide, boride, silicide, B4C, BN, and diamond. Soda lime silicate glass, alumino silicate glass, etc., are adequately used for the substrate 2 according to the purpose of use. The uniform inorg. film having high hardness and high m.p. is thus easily formed on the substrate 2 having a large area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for forming a hard inorganic film on a glass substrate surface.

[Prior art] Various physical vapor deposition methods (PVD methods) and various chemical vapor deposition methods (CVD methods) have been conventionally used as methods for forming hard SSI on glass.
D method) is known, but in the CVD method, the substrate is generally
As a coating method for optical applications on large-area glass substrates that are difficult to heat, such as the need to heat them to around 0°C and the problem of in-plane uniformity of film thickness over a large area, It was not suitable. On the other hand, PvD methods include vacuum evaporation, ion blating, and sputtering, but sputtering is mainly used as a coating method for large-area glass substrates due to its reproducibility, uniformity, controllability, and productivity. has been attempted.

However, none of the current vacuum deposition methods, ion blasting methods, and sputtering methods are sufficient for the purpose of forming an inorganic film with extremely high hardness.

On the other hand, the arc evaporation method was developed as a third physical thin film formation method different from the normal vacuum evaporation (thermal evaporation) method and sputtering method, and it produces extremely thin film formation methods that cannot be obtained with conventional methods. Hard, dense hard coating (e.g. TiN1i)
). In particular, it is considered to be the most promising method for forming carbide yA (for example, TiN film) on cutting tools, and has recently begun to be used in production.

TiN films have been mainly attempted using the arc evaporation method, in which Ti is used as a starting material and Ti is deposited in high-density nitrogen plasma
Synthesize N film. This means that an arc discharge occurs between the Ti target and the grounded arc chamber,
Since current concentration occurs in a very small portion of the Ti target, the temperature locally becomes high and Ti instantly turns into plasma. In the case of a conductive substrate such as a metal, positive Ti ions and positive N◆ ions generated during arc discharge are attracted to the substrate that is negatively biased with direct current, and Tp on the substrate is attracted.
It is said that a TiN film is produced by the reaction of N4 and N4. T
The chemical reactivity of both i and nitrogen increases when they are ionized, and due to the high kinetic energy obtained by acceleration by applying a DC voltage, a very dense and hard film similar to that of bulk TiN can be obtained. It is said that Almost 100% of the evaporated Ti is ionized, and the ionization rate is one or two orders of magnitude higher than that of ion blating or sputtering using normal glow discharge, and it is said that it is possible to obtain a much superior film. There is.

However, until now, the thickness of TiN M for the above-mentioned applications has been quite thick, ranging from several µm to several tens of µm, and its application has been limited as it is mainly used for metal substrates. Thin film (film thickness;
Formation (from tens to thousands of people) had not yet been attempted.

On the other hand, in order to form a highly hard film on the glass substrate surface,
Oxides, nitrides, carbides, borides, and BN originally exhibit high hardness in their bulk state.

It is optimal to achieve the bulk characteristics of bad, diamond, etc. with a thin film. However, these materials also have high melting points, and it has been difficult to form a film with properties close to bulk on a low-temperature substrate using conventional vacuum evaporation methods or sputtering methods. Recently, various ion blating methods have been developed, and attempts have been made to form harder and denser films, but these methods are still insufficient.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method and an apparatus for forming a hard film with high hardness on a large-area glass substrate surface, which has been difficult to achieve using conventional methods.

[Means for Solving the Problems] The present invention was invented as a result of research based on the above-mentioned object, and the gist of the first invention is to move a glass substrate horizontally in a vacuum chamber. The second aspect of the invention relates to a method for forming an inorganic film on a glass substrate surface, characterized in that an evaporation material for forming an inorganic film is evaporated by arc discharge, and the inorganic film is deposited on the glass substrate. In a vacuum evaporation apparatus that evaporates an evaporation material for forming an inorganic film in a vacuum chamber to deposit an inorganic film on a glass substrate, an arc discharge source is provided as an evaporation source for evaporating the evaporation material for forming an inorganic film, and The present invention relates to an apparatus for forming an inorganic film on the surface of a glass substrate, characterized in that an electrode plate for applying a DC voltage or high frequency is arranged on the am of the glass substrate.

The present invention will be explained in more detail below.

In the present invention, the glass substrate on which the Sa film is formed may be soda lime silicate glass,
Aluminosilicate glass, borosilicate glass, lithium aluminosilicate glass, quartz glass, etc. are used.

In addition, as the inorganic film having high hardness formed on the glass substrate surface, thin films made of various inorganic materials may be used depending on the purpose of use, such as oxide films, nitride films, carbide films, boride films, and silicide films. 84G, 8N, diamond, or a multicomponent film 1 containing at least two of carbon, boron, and silicon, such as an oxynitride film, a boron carbide film, a boron nitride film, a silicon nitride film, a silicon carbide film, or A composite film of the various substances listed above is selected.

For example, when used as heat-reflecting glass or a reflective mirror, inorganic materials such as oxides, nitrides, and carbides are selected as the inorganic film; and when used as antireflection glass, inorganic materials such as oxides, etc. are selected as the inorganic film. When used as a photomask blank, nitride, carbide, oxide, silicide, or a combination thereof is used as the inorganic film, and when used as a glass magnetic disk, A ferrite or the like is used as the inorganic film, and when used as a conductive glass, a conductive oxide or the like is used as the inorganic film.

In the present invention, a plurality of different types of inorganic films formed according to the present invention may be laminated, or an inorganic film formed according to the present invention may be combined with a sputtering method, a vacuum evaporation method, or an ion grating method. Various films formed by the above may be stacked.

For example, if a 100-layer Ti film is formed by sputtering, nitrogen ion implantation is performed on this film, and a 1,000-layer TiN film is formed on top of this film by arc evaporation, a TiN reflective film with excellent adhesion and hardness can be formed. (gold color).

Next, the present invention will be explained with reference to FIG. The apparatus for forming an inorganic film on a glass substrate surface shown in FIG. 1 is an example of an in-line type apparatus. In FIG. 1, a glass substrate 2 moves linearly in the horizontal direction, and as it passes under an arc evaporation source 1, which is an evaporation source for forming an inorganic film, and is placed above it, an inorganic film is formed by evaporation. It is formed.

At this time, the evaporation source for forming the inorganic film is evaporated by arc discharge, and the film is formed by a so-called arc evaporation method. 3
1 shows a back electrode plate placed on the back surface of a moving glass substrate, so that evaporated particles evaporated by arc discharge are ion-accelerated. What is the thickness of the membrane?

It is determined by the moving speed of the glass substrate and the arc evaporation rate (power input to the arc source). If the moving speed of the glass substrate, the arc evaporation rate, the pressure, and other conditions are constant over time, a uniform film thickness distribution can be obtained in the direction of movement of the glass substrate. The uniformity of the film thickness in the lateral direction perpendicular to the direction of travel is achieved by arranging multiple arc evaporation sources as point sources in the lateral direction. It becomes possible to form a uniform film on a glass substrate.

When accelerating ions on an insulating substrate such as glass, charge-up becomes a problem. therefore,
The solution is to use high frequency bias,
A method of using a charge-up prevention grid at the same time as a DC bias, a method of neutralizing using thermoelectrons with a DC bias, etc. can be adopted.

In the present invention, as shown in FIG. 2, in order to attract metal film ions and nitrogen pressure ions to the surface of the glass substrate and form high-density plasma near the glass substrate, a DC voltage is applied to the back side of the glass substrate. Alternatively, a back electrode plate 3 for high frequency application can be arranged. Note that if the surface of the glass can be coated with a conductive wave Jll (for example, a metal film) in advance, substrate biasing can also be achieved by electrically connecting this conductive coating to the substrate holder.

As the back electrode plate 3 placed on the back side of the glass substrate, S
Electrodes made of metals such as OS, AI, and Cu are used. In this case, the back electrode plate is placed slightly away from the glass substrate (for example, about one layer), facing the arc source, and placed stationary.
As mentioned above, in the case of direct current acceleration, it is also effective to provide a grid 4 made of thin metal wire or the like on the arc source side of the glass substrate, as shown in FIG. 2, in order to prevent charge-up. In this case, the spacing between the metal wires of the grid is 2c
m or less is appropriate. If the interval is longer than this, the effect of preventing charge-up will be lost. Also.

It is effective that this grid is electrically at the same potential as the back electrode of the glass substrate. It is effective to extend the thin metal wire in a direction perpendicular to the direction of movement of the glass substrate so as not to affect the film thickness distribution.

The pressure during arc evaporation is usually on the order of 10-2 Torr, but in the case of film formation for optical purposes on a glass substrate, the pressure is on the order of 10-'Torr, preferably 5X 101
TorrNIX 10-2 Torr is effective. If the pressure is higher than this, it will be difficult to form a film with properties close to bulk due to the influence of scattering by the gas, and if the pressure is lower than this, it will be difficult to sustain arc discharge.

[Function] In the present invention, by forming an inorganic film on the glass substrate by arc evaporation while moving the glass substrate, it is possible to form a uniform film on a large area glass substrate. By changing the speed and the power input to the arc evaporation source, it is possible to control the film thickness, and moreover, it is possible to form several hundred thin films for the desired optical film.

Furthermore, compared to conventional methods, the arc evaporation method is characterized by a higher film deposition speed, and is also advantageous in that it can achieve a production speed higher than that of the sputtering method. Uniformity of the film thickness in the direction of movement of the glass substrate can be ensured by keeping the feeding speed of the glass substrate and power input to the arc evaporation source constant, and uniformity in the direction perpendicular to the direction of movement of the glass substrate can be ensured. can be improved by using masks. This is also one of the features of the in-line type device as shown in Figure 1.2.

The arc evaporation source can coat from either the top, bottom, left or right, and although the coating direction is not specified, in the case of large-area glass substrates, the arc source should be placed at the top for ease of handling. An arrangement with the substrate facing down is preferred.

The effect of the grid is thought to be that secondary electrons generated by ion bombardment on the glass substrate are pushed back by the negative potential of the grid, thereby reducing charge-up.

[Examples] Example 1 A 30 cm square glass substrate was prepared and washed using a commercially available neutral detergent, running water, ethanol, and N2 drying. This glass substrate was set in the in-line type arc evaporation apparatus shown in Fig. 1, and the air was evacuated to 1 × 1 O-5 Torr.
Then, N2 gas was introduced. IX 101 Torr
After starting the arc discharge on the stand, increase the pressure to 2X 1O-3T.
Controlled to orr.

Ti was used as a target material as an evaporation source. In this state, the arc evaporation zone was filled with high-density plasma.Then, the glass substrate was moved 30 cm in 7 minutes to pass through the arc evaporation zone. As a result, a TiN thin film with a reflection color of about 500 deer gold was obtained on glass. Since there was only one evaporation source, a mask was used to ensure film thickness uniformity in the direction perpendicular to the direction of travel. As a result, 3
The film thickness uniformity was within ±10% on a 0 cm square glass substrate. Note that the accelerating voltage applied to the back electrode of the glass substrate was -50V.

The TiN film obtained by this method had excellent durability, high infrared reflection performance, and excellent scratch resistance.

Example 2 A 60 cm square glass substrate was prepared and washed using a commercially available neutral detergent, running water, ethanol, and N2 drying. This glass substrate was set in an in-line type arc evaporation apparatus as shown in the figure, which is equipped with a substrate movement mechanism. This IX
The atmosphere was evacuated to 1O-5 Torr, and then N2 gas was introduced. Arc discharge was started using Zr as a target on a 1O-2 Torr platform, and the pressure was increased to 2X 1O-3.
It was controlled to Torr.

Next, 1500V was applied to the metal electrode plate placed on the back side of the glass substrate, facing the arc evaporation source, and thin metal wires were placed on the glass at 1 cm intervals on the arc evaporation source side of the substrate from the glass substrate. The same voltage of <-500 V was applied to a charge-up prevention grid stretched perpendicular to the direction of movement of the substrate, and the glass substrate was moved under that condition to pass through the arc deposition zone. The conveyance speed is 30 cm/min. As a result, a ZrN thin film with a 500-gold reflective color was obtained. Note that during film formation,
The glass substrate was not heated.

Two arc evaporation sources were used, and uniformity of the film thickness in the direction perpendicular to the direction of movement of the glass substrate was ensured using a mask. As a result, film thickness uniformity within ±10% was obtained over the entire glass substrate. The obtained ZrN thin film had a low electrical resistance of 10 −5 Ωam and a high infrared reflectance of 80%.

[Effect of the invention] The effects of the present invention are as follows.

l) A uniform film can be easily formed on a large area glass substrate.

2) High hardness, high melting point inorganic films such as TiN and ZrN can be formed with properties close to bulk.

3) An acceleration effect can be obtained even on insulating glass substrates, and the adhesion can be strengthened.

4) Other methods (e.g. sputtering method, ion implantation method, etc.)
For example, sputter film formation,
A combination of ion implantation treatment and arc evaporation film formation is possible.

[Brief explanation of the drawing]

Figures 1 and 2 schematically show a specific example of the in-line inorganic film forming apparatus of the present invention. In Figure 0, (1) shows an arc evaporation source, and (2) shows a glass substrate. of,
(3) shows the back electrode plate, and (4) shows the charge-up prevention grid. 1゛;・°. Figure 1 Figure 2

Claims (7)

[Claims] (1) An inorganic film on the surface of a glass substrate characterized by evaporating an evaporation material for inorganic film formation by arc discharge while moving the glass substrate horizontally in a vacuum chamber, and depositing the inorganic film on the glass substrate. How to form. (2) The inorganic film is made of oxide, nitride, carbide, boride,
The method for forming an inorganic film on a glass substrate surface according to claim 1, wherein the inorganic film is made of an inorganic material containing at least one of silicide, B_4C, BN, and diamond. (3) Reduce the pressure inside the vacuum chamber to 5 x 10^-^4 Torr ~ 1
A method for forming an inorganic film on a glass substrate surface according to claim 1, characterized in that the vapor deposition is performed under conditions of x10^-^2 Torr. (4) An electrode plate for applying a DC voltage is placed on the back side of the moving glass substrate, and a fine metal wire grid is placed on the evaporation source side of the substrate perpendicular to the moving direction of the glass substrate. A method for forming an inorganic film on a glass substrate surface according to claim 1, characterized in that the inorganic film is deposited in a state where the metal wire grid and the fine wire grid are at the same potential. (5) In a vacuum evaporation device that evaporates an evaporation material for inorganic film formation in a vacuum chamber to deposit an inorganic film on a glass substrate, an arc discharge source is provided as an evaporation source for evaporating the evaporation material for inorganic film formation; An apparatus for forming an inorganic film on the surface of a glass substrate, characterized in that an electrode plate for applying a direct current voltage or high frequency is arranged on the back side of a moving glass substrate. (6) An apparatus for forming an inorganic film on a glass substrate surface as set forth in claim 5, characterized in that a grid of thin metal wires is disposed on the evaporation source side of the substrate, orthogonal to the moving direction of the glass substrate. (7) An apparatus for forming an inorganic film on a glass substrate surface according to claim 5, characterized in that a neutralizing thermoelectron generating filament is disposed between the glass substrate and the arc discharge source.