JPS62229550A - Method and apparatus for producing optical disk - Google Patents

Abstract

PURPOSE:To form a transparent protective interference film to be formed on a substrate surface to the compsn. approximate to the stoichiometric compsn. by simultaneously irradiating a metallic particle flux and reactive gas particle flux on the surface of the disk held in a vacuum. CONSTITUTION:The substrate 14 held to a substrate holder 5, a metallic particle flux supplying source 7 such as magnetron sputtering source or vacuum deposition source and a reactive gas particle flux supplying source 10 are provided to a vacuum vessel 1. The inside of the vessel 1 is evacuated and the metallic particle flux of Si, etc., from the supplying source 7 and the reactive gas particle flux of nitrogen, etc., from the supplying source 10 are simultaneously irradiated on the substrate 14. Reaction is thereby induced effectively on the surface of the substrate 14 and the metallic compd. film of SiN or the like having nearly the stoichiometric compsn. is formed to uniform quality at a low temp. and high speed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method and apparatus for manufacturing an optical disc for recording and reproducing information by irradiating a light beam, and particularly relates to a method and an apparatus for manufacturing an optical disc that records and reproduces information by irradiating a light beam. It is used in the manufacture of optical discs with

(Prior Art) Optical discs, on which information is recorded and reproduced by irradiating a light beam, are expected to be used as non-contact large-capacity memories. This optical disc basically consists of a disc substrate and a recording layer provided on its surface.

In optical discs, in order to prevent errors caused by dirt and dust that exist near the focal point of the recording/reproducing light beam, the light beam is irradiated onto the recording layer through the substrate, and the reflected light from the recording layer is detected. It has become common sense to access information. Further, in order to quickly access the light beam to a predetermined position, a track for guiding the light beam head is required, and it is desirable that the tracks be provided in advance as a group on the substrate. For this reason,
The substrate material of the optical disk must be transparent and have excellent group formability, and transparent resin materials such as polymethyl methacrylate, polycarbonate, and epoxy are practically suitable.

On the other hand, a wide variety of recording layer materials, including metals, metalloids, semiconductors, semi-organic materials, and organic dye-based materials, have been put to practical use or researched and developed. Among these, rare earth-transition metal amorphous ferrimagnetic alloy films that utilize the magneto-optical effect as recording layers, and Cu-AJ2 and AQ-Z that utilize crystal structure transformation, are particularly suitable for recording layers.
When using a metal material such as an n-based film, a protective film for preventing oxidation is required in most cases. When a transparent resin substrate and a recording layer as described above are combined, since the substrate has gas permeability, the protective MTA must be provided not only on the upper surface of the recording layer but also between the recording layer and the substrate. It won't happen. In this case, since the light beam is irradiated through the substrate as described above, the protective film also needs to be transparent to the recording/reproducing light beam. In addition, when a gas-impermeable glass substrate is used, it is sufficient to provide the W1 film only on the upper surface of the recording layer, but this prevents a decrease in recording sensitivity due to heat dissipation from the recording layer to the protective film. Therefore, it is preferable to use a transparent dielectric material with low thermal conductivity as the protective film material. Furthermore, if the protective film is transparent, multiple interference of light occurs within the protective film, resulting in an enhancement effect of the reproduced signal. For the reasons described above, a transparent protective interference film has become an important component in optical discs.

By the way, as a method for forming the above-mentioned protective interference film, sputtering method or vapor deposition method has conventionally been mainly used. This means that these methods lower the substrate temperature from room temperature to several tens of degrees Celsius.
This is because a relatively homogeneous film can be obtained over a large area while being maintained at a relatively low temperature, and the device configuration is simple.

However, when a protective interference film made of a metal compound is formed using a sputtering method or a vapor deposition method, the composition of the metal compound deviates from the stoichiometric composition and the refractive index of the film becomes a desired value. Moreover, there was a problem that the film formation rate was slow at about several tens to 100 people/1n at most.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned problems. It is an object of the present invention to provide a method for manufacturing an optical disc that can be formed in a manner similar to that of the present invention, and a simple manufacturing apparatus for implementing this method.

[Structure of the Invention] (Means for Solving the Problems) A method for manufacturing an optical disc according to the first invention of the present application involves depositing a metal particle bundle and a reactive gas particle bundle on a disk substrate surface held in a vacuum. It is characterized in that it is simultaneously irradiated to form a transparent protective interference film made of a metal compound whose constituent components are metal atoms and reactive gas atoms on the substrate.

Further, the optical disc manufacturing apparatus of the second invention of the present application includes: a vacuum container; a substrate holding section that holds a disk substrate; a metal particle bundle supply source that is provided opposite to the substrate holding section and generates a metal particle bundle; The present invention is characterized by comprising a reactive gas particle bundle supply source that is provided opposite to the substrate holding part and generates a reactive gas particle bundle.

(Function) According to the method for manufacturing an optical disk as described above, the substrate is irradiated not only with a bundle of metal particles but also with a bundle of reactive gas particles, so that reactions occur efficiently on the substrate surface and the stoichiometric composition is It is possible to form a metal compound film having a composition close to 1 at high speed. Further, the optical disk manufacturing apparatus of the present invention can be manufactured extremely easily, since it is only necessary to attach a reactive gas particle flux supply source to a conventional sputtering apparatus or vacuum evaporation apparatus.

Note that when forming an insulating protective interference film, there is a risk that the incidence of the reactive gas particle flux may become unstable due to charge-up of the protective interference film. It is desirable to provide a means for neutralizing the gas so that a bundle of neutral reactive gas particles is incident on the substrate.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

First, a schematic configuration of a thin film forming apparatus prototyped for carrying out the method of the present invention will be explained with reference to FIG.

In FIG. 1, a vacuum vessel 1 is provided with an exhaust system 2, an Ar gas supply system 3, and a vacuum gauge 4.

A substrate holder 5 is inserted into one wall of the vacuum container 1 , and the substrate holder 5 is rotated by a motor 6 . Further, a metal particle bundle supply source (hereinafter sometimes abbreviated as MBS) 7 is provided on the other wall surface of the vacuum container 1 so as to face the substrate holder 5, and this MBS'7 has an MBS power source 8. is connected.

A shutter 9 is provided near the MBS 7 on the substrate holder 5 side. Furthermore, a reactive gas particle flux supply source (
(hereinafter sometimes abbreviated as GBS) 10 is provided,
A reactive gas is supplied to this GBSlo from a reactive gas supply system 11, and a GBS power supply 12 is connected. A shutter 13 is also provided on the substrate holder 5 side near this GBS 10. Then, the substrate 14 is placed in the substrate holder 5.
is fixed.

As the MBS 7, for example, a magnetron sputter source shown in FIG. 2 or a vacuum evaporation source shown in FIG. 3 is used.

In FIG. 2, a cathode 22 is fitted into a hole provided in a vacuum container 1 via an insulating shield 21.
For example, a 3i target 23 is placed on this cathode 22. Further, a conductive casing 24 is attached to the outside of the vacuum container 1 so as to be connected to the cathode 22. A permanent magnet 25 is arranged in this housing 24 so as to be spaced apart from the center of the target 23, and this permanent magnet 25 is connected to the motor 2.
Rotated by 6. In addition, the housing 24 includes an MBS power supply 8.
is connected to the cathode 22 through the housing 24 and high voltage is connected to the cathode 22
and the vacuum container 1, which serves as an anode. When a high voltage is applied while rotating the permanent magnet 25, a doughnut-shaped magnetron plasma is generated on the target 23, and a metal particle flux can be supplied.

In FIG. 3, a high-frequency induction coil 32 is arranged around the outer periphery of a crucible 31, and a metal melted by high-frequency induction heating, for example, molten S;3a, is housed in the crucible 31.
This can be evaporated to provide a metal particle bundle.

On the other hand, as the GBS 10, for example, a device as shown in FIG. 4 is used. In FIG. 4, there are two tungsten rods 42.4 inside the cylindrical device main body 41.
2 are provided, and when a high voltage is applied to these from the GBS power supply 12, a saddle-shaped electric field is formed. Then, when a reactive gas is supplied from a reactive gas supply system (not shown), these are excited and become reactive gas plasma, which sends a bundle of reactive gas particles to the outside (substrate holder side) through a window provided in the main body 41 of the apparatus. It can be irradiated. In addition, the device main body 4
A carbon mesh 43 can be attached to the window 1. When the carbon mesh 43 is attached, the reactive gas particle flux passing through it is neutralized.

Example 1 A magnetron sputtering source shown in FIG. 2 as MBS7,
The apparatus shown in FIG. 4 was used as GBSlo, and the R[formation apparatus shown in FIG. 1] was manufactured. Further, as the substrate 14, a CZ-8i substrate, an FZ-8i substrate, a glass substrate with a mask, a polymethyl methacrylate substrate, and a Na(4
Using five types of substrates, SiN films were formed under the following conditions, and the films were evaluated.

First, a substrate is fixed on the substrate holder 5, and then placed in the vacuum container 1.
After installing the inside of the vacuum container 1, operate the exhaust system 2 to exhaust the inside of the vacuum container 1.
X 10-? It was exhausted to Torr. Next, 9. Ar gas is supplied from the Ar gas supply system 3. N2 gas was supplied from the reactive gas supply system 11 at a flow rate of γsecm, and N2 gas was supplied from the reactive gas supply system 11 at a flow rate of 0.3secm. To
It was held at rr. Next, with the shutter 9.13 closed, 600W RF power from the MBS power supply 8 is used as a sputtering source, and 1kV high voltage is applied from the GBS power supply 12 to the GBS1.
The voltage was applied to tungsten rods 42 and 42 within 0, respectively. As a result, donut-shaped magnetron plasma emission was observed on the 3i target 23 in MBS7, and plasma emission was observed inside GBS10.

Conditioning was performed in this state for about 10 minutes.

Next, drive the motor 6 to move the substrate holder 5 at i2rpm.
5iNil was formed for about 20 minutes by opening the shutters 9 and 13 at the same time. Thereafter, the shutters 9 and 13 are closed simultaneously, the motor 6, the MBS power supply 8 and the GBS power supply 12 are turned off, and the gas supply from the Ar gas supply system 3 and the reactive gas supply system 11 is stopped. introduced an atmosphere. Subsequently, the substrate holder 5 was taken out and the film formed on the substrate surface was evaluated as follows.

Regarding the sample of the glass substrate with a mask, after etching off the mask with an organic solvent, the difference in level between the substrate and 5iNG was measured using a stylus-type film thickness meter. As a result, within a radius of 1 to 7 cttr from the center of the substrate holder 5! The variation in IQu was within 5%, and the average film thickness was 5,700. Therefore, the film formation rate was 285 people/main.

The transmittance of a sample of the polymethyl methacrylate substrate to light having a wavelength of 830 nm was measured. As a result, a transmittance of 90% including the substrate was obtained. Further, there was no thermal damage to the substrate.

The infrared absorption spectrum was measured for a sample of the FZ-8il plate. As a result, 5i near 850α“l
A steep peak due to -N bonds was observed, and it was also found that no impurities such as oxygen were mixed into the film.

A chemical quantitative analysis was performed on a sample of the CZ-8i substrate. As a result, the mass ratio of S; and N is Si/N=1
．． 5, and it was confirmed that the film had a nearly stoichiometric composition (S!3N+).

A sample of the NaCn substrate was subjected to TEM observation and electron beam diffraction. As a result, the film was microscopically extremely flat and uniform. Furthermore, crystallographically, the film was found to be amorphous.

Comparative Example 1 Using the thin film forming apparatus used in Example 1 above, GBS7
By not operating the film, film formation was performed by the conventional method of reactive sputtering using a 3i target. The membrane evaluation substrate used, the conditions such as pressure and time, the operation of other equipment other than the operation of the equipment to operate GBS7, and the evaluation method of the formed film were all performed in the same manner as in Example 1. .

The average thickness of the obtained membrane was 4000.

The transmittance was 10% or less, and it was opaque. In the infrared absorption spectrum, almost no absorption of 5i-N bonds was detected. In chemical quantitative analysis, mass ratio Si/N=15
It was found that the film was mostly composed of 3i.

The difference in characteristics of the films formed by the methods of Example 1 and Comparative Example 1 is considered to be due to the following reasons. That is, in Comparative Example 1, since the substrate surface was not irradiated with the reactive nitrogen gas particle flux, the 3iN production reaction mainly proceeded only in the magnetron plasma near the Si target 23. Furthermore, the partial pressure of N2 gas is 9×10 4 Torr, and the amount of N2 gas is insufficient. For this reason, the constituent elements of the formed film are extremely Si-excessive. On the contrary,
In the method of Example 1, even when the amount of N2 gas is small, since the substrate is irradiated with a reactive nitrogen gas particle flux, the reaction to generate SiN occurs efficiently on the substrate surface, and SiNgl with a near stoichiometric composition occurs. is generated at high speed.

It is believed that even with the conventional method similar to Comparative Example 1, if the gas conditions are optimized, a film having a composition close to the stoichiometric composition can be formed. Actually, when a film was formed in the same manner as in Comparative Example 1 by changing the N2 gas partial pressure, the N2 gas partial pressure was 3X104T orr or more, the mass ratio Si/N was 2 or less, and about 1000% was deposited on a polymethyl methacrylate substrate.
The transmittance was over 80% for the sample on which the human membrane was formed. However, the film-forming rate was very slow, less than 7 m1n for 70 people (this film-forming speed was based on Si3 as the target).
(This is approximately the same level as the sputtering method using N4). This is because under the gas conditions where the N2 gas partial pressure is high as described above, the SiN production reaction also occurs on the target.

Example 2 The vacuum evaporation source shown in FIG. 3 was used as MB57, and the device shown in FIG. 4 was used as GBSlo.
! A forming device was created. Using this device, the Ar gas supply system 3 is not operated, and high purity N is supplied from the reactive gas supply system 11.
2 gas was supplied at a flow rate of 0.5 sec to maintain the gas pressure in the vacuum vessel 1 at 1.5 x 10' Torr,
The power input to the high frequency induction coil 32 was 1 kW, and the other conditions and operations of each device were exactly the same as in Example 1.

A SiN film was formed, and the film was evaluated in the same manner as in Example 1.

As a result, approximately 400
The transmittance of the sample in which no film was formed was 90%. In the infrared absorption spectrum, a peak at 850α°1 was observed. In chemical quantitative analysis, the mass ratio Si/N-1,
5 was obtained.

Next, a SiN film is formed by keeping the input power to the high-frequency induction coil 32 and GBSlo constant and changing the N2 gas pressure in the vacuum chamber 1. The relationship between this and the film formation rate was investigated. The results are shown in FIG.

As is clear from Fig. 5, PN<1X10'T or
At r, when the Si/N mass ratio exceeds 2, there is an excess of Si compared to the stoichiometric composition and the transmittance decreases, but when PN > 1.5
At x 1Q' Torr, the Si/N mass ratio is approximately constant at approximately 1.5. On the other hand, the deposition rate is PN
It reached a peak at -2X10' Torr, decreased before and after that, and particularly decreased extremely when PN>5X104 Torr. The dependence of the film formation rate on PN can be explained as follows. That is, the N2 gas pressure is 1×104 tons
If it is low, below rr, the density of Si particles supplied onto the substrate will be excessive compared to the density of reactive nitrogen gas particles, and the film formation rate will be lower than S.
The deposition rate approaches that of 1 alone. N2 gas pressure is 2X104
When the temperature rises to around Torr, the sIN production reaction actively occurs on the substrate surface, so the film formation rate increases more than the deposition rate of 3i alone. However, the N2 gas pressure is 5X 10'
When the temperature rises to around Torr, the density of reactive nitrogen gas particles becomes higher than the density of Si particles supplied onto the substrate, and a re-sputtering phenomenon of the film occurs due to the incidence of reactive nitrogen gas particles, and the film formation rate gradually decreases. . Furthermore, when the N2 gas pressure rises above 5×10 4 Torr, the SiN production reaction actively occurs on the 3i evaporation surface, and the film formation rate rapidly decreases.

In order to experimentally confirm the above qualitative interpretation, a diameter of 1ffi was placed in the central part of the substrate holder 5 shown in FIG.
A l+ differential exhaust orifice is provided, and a quality analysis tube (
(hereinafter abbreviated as QMS) was connected to measure the incident density of reactive nitrogen gas particles and Si particles onto the substrate surface. Quantification of the incident density was determined using the obtained N2'', N4'' and 3i
+ peak intensity was corrected with QMSIlt sensitivity, and the background level was sufficiently small, less than 1/100 of the signal), and from the deposition rate of Si alone and 0MS peak value of 3i alone, The relationship with the incident density was derived. The results are shown in FIG.

As is clear from FIG. 6, the incident density of reactive nitrogen gas particles increases almost linearly as the N2 gas pressure increases. On the other hand, the incident density of 3i particles is P N −
I at 0! (indicated by arrow in the figure) to PN-5x10
'Gradually decreases to Torr, PN >5X10' T
It is rapidly decreasing at orr. And, quantitatively, PN-2
At X104 Torr, the incident density ratio of Sl and N is s r
/N-3/4, which agrees with the stoichiometric composition ratio. In addition,
The incident density of reactive nitrogen gas particles is excessive (S i/N<3
/4), as shown in Figure 5, the Si of the film
/N mass ratio is constant at approximately 1.5, which is close to the stoichiometric composition ratio, so once the 3i3N+ production reaction has progressed sufficiently on the substrate, excess reactive nitrogen gas particles will contribute to the reaction. Therefore, it is thought that it will not be re-released into the gas phase and incorporated into the membrane.

Comparative Example 2 Using the thin film forming apparatus used in Example 2 above, GBS7
By not operating the SiN film, a conventional reactive vacuum evaporation method was used to form a SiN film.

As a result, in Example 2, a good quality SiN film was obtained at high speed.
When the Si/N￥f ratio is 3 or more, Si
An excessively opaque film was formed. PN＞7X104To
Above rr, the Si/N mass ratio was about 1.5, but
The film formation rate was significantly reduced to 7 mtn for 50 people.

Example 3 In order to investigate the influence of the electrical properties of reactive nitrogen gas particles from GBSIO on the properties of the SiN film formed on the substrate, a carbon mesh 4 of GBSLO as shown in FIG.
A thin film forming apparatus similar to that prepared in Example 1 above was manufactured by using the same device from which No. 3 was removed.

First, a QMS was attached to each of the thin film forming apparatuses of Example 1 and Example 3, and the constituent components of the gas were analyzed.
The GBSlo
The neutralization rate of reactive nitrogen gas particles was investigated. As a result, in the device of Example 1 (with carbon mesh), the ratio of lighting time to non-lighting time was approximately 10=1, and the neutralization rate was approximately 9.
In contrast, in the device of Example 3 (without carbon mesh), the ratio of lighting time to non-lighting time was about 10, and the carbonation rate was about 30%.

Next, a film of StN was formed using the apparatus of Example 3. The conditions such as the substrate for film evaluation, pressure and time, the operation of the equipment, and the method for evaluating the formed film are all the same as in Example 1.
It was made the same as.

As a result, a SiN film with a thickness of approximately 5,000 layers was obtained. Furthermore, the transmittance of the polymethyl methacrylate substrate sample was 80%, which was lower than that of Example 1.

Therefore, when using a sample of a CZ-8+ substrate and performing Auger spectroscopy while etching it in the film thickness direction, the film showed regions with Si3N+ and regions with an excess of Si compared to the stoichiometric composition. It turned out that it has a layered structure. This is carbon mesh 43
This is thought to be due to the fact that the main component of the reactive nitrogen gas particle bundle is ions when no ion is provided. That is,
When insulating Si3N+ll is formed on the substrate surface, it is gradually charged up and begins to receive electrical recoil from the N+ powder particle substrate, forming a region with an excess of Si compared to the stoichiometric composition. And Cha.

-When the shearing is eliminated, Si3N+ is generated again. By repeating these processes, a structure is formed in which a SigN+ region and a region containing too much Si compared to the stoichiometric composition are stacked.

From the results of Example 1, Example 3, and Comparative Example 1, it was found that
It can be seen that by simultaneously irradiating the i-particle flux and the reactive nitrogen gas particle flux, a transparent protective interference film made of SiN having a composition close to stoichiometric composition can be formed at high speed. In addition, as a transparent protective interference film, the above-mentioned S
When forming an insulating film such as iN, it is desirable to neutralize the reactive gas particle flux. however,
When forming a conductive film such as ITO as a transparent protective interference film, it is not necessarily necessary to neutralize the reactive gas particle bundle.

In addition, although the above embodiment describes the case where the present invention is applied to the formation of a SiN film, the material of the film formed by the present invention is not limited.

For example, in addition to 3i as a metal particle bundle, A°C, In.

Rare earth metals, Ge, Zn, etc. are used as reactive gas particle bundles in addition to N2, 02, N28, etc., respectively.
Various types of transparent protective interference films such as N4, GeO2, InN, In203, ZnS, rare earth oxides, and rare earth nitrides can be formed with high quality and at high speed.

[Effects of the Invention] As detailed above, according to the optical disc manufacturing method and manufacturing apparatus of the present invention, a transparent protective interference film made of a metal compound having a composition close to the stoichiometric composition can be formed homogeneously and quickly at low temperatures. As a result, optical discs with a long life and high reproduction signal strength can be produced with good agricultural productivity, and other remarkable effects can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an optical disk manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a magnetron sputter source (metal particle flux supply source) used in the same manufacturing apparatus.
Figure 3 is a cross-sectional view of the vacuum evaporation source (metal particle bundle supply source) used in the same manufacturing equipment, Figure 4 is a perspective view of the reactive gas particle bundle supply source used in the same manufacturing equipment, and Figure 5 is the main A characteristic diagram showing the relationship between N2 gas pressure, Si/N″IN ratio, and film formation rate in Example 2 of the invention, and FIG. 6 shows the relationship between N2 gas pressure and reactive nitrogen/gas particles and 3
FIG. 3 is a characteristic diagram showing the relationship between the i-particles entering the substrate and the tJ4 density. DESCRIPTION OF SYMBOLS 1... Vacuum container, 2... Exhaust system, 3... Ar gas supply system, 4... Vacuum gauge, 5... Substrate holder, 6...
・Motor, 7... Metal particle bundle supply source (MBS), 8.
... MBS power supply, 9 ... Shutter, 10 ... Reactive gas particle flux supply source (Gas), 11 ... Reaction system gas supply system, 12 ... GBSffi source, 13 ... Shutter, 14 ...Substrate, 21...Shield, 22...
・ll! 23... Si target, 24... Housing, 25... Permanent magnet, 26... Motor, 31...
- Crucible, 32... High frequency induction coil, 33... Melting 3i, 41... Device main body, 42... Tungsten rod, 43... Carbon mesh. Applicant's representative Patent attorney Takehiko Suzue Figure 1 fs4 Figure N2 ttx pressure [Torrl Figure 5 N2 gas pressure [Torrl

Claims (4)

[Claims] (1) In manufacturing an optical disk in which a protective interference film and a recording layer are formed on the surface of a disk substrate, the surface of the disk substrate held in vacuum is simultaneously irradiated with a metal particle bundle and a reactive gas particle bundle. A method for manufacturing an optical disc, comprising forming a transparent protective interference film made of a metal compound containing metal atoms and reactive gas atoms on the surface of a substrate. (2) The method for manufacturing an optical disk according to claim 1, wherein the main component of the reactive gas particle bundle is electrically neutral. (3) a vacuum container, a substrate holder that holds a disk substrate, a metal particle bundle supply source that is provided opposite to the substrate holder and generates a metal particle bundle, and a reactive metal particle bundle that is provided opposite to the substrate holder and that generates a metal particle bundle; 1. An optical disc manufacturing apparatus comprising: a reactive gas particle bundle supply source that generates a gas particle bundle. (4) The optical disk manufacturing apparatus according to claim 3, wherein the reactive gas particle flux supply source has means for neutralizing the reactive gas particle flux.