JP2001143332A - Method for direct dry mastering of stamper for optical disk and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for direct dry mastering of a stamper for an optical disk which is capable of making clean degree, management easy and lessening the adhesion of foreign matter, and an apparatus therefor. SOLUTION: A substrate coated with a negative type photoresist is rotated and is continuously subjected to surface exposure, heat treatment, development by a dry process, etching and resist removal, thereby, signal projections are formed on the substrate surface and the substrate is worked to have a stamper size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Generally, a process for producing a master of an optical disk is called "mastering". In this process, a master of metal such as nickel called "stamper" is finally produced. This stamper is used as a mold in a later molding step, and a large number of optical disc copies are produced using the mold. The present invention provides a direct dry mastering stamper for optical discs, which is manufactured by dry etching the stamper in a shorter time and at a lower cost with a smaller number of steps than before, with a high yield.
The present invention relates to a direct dry mastering method and apparatus for an optical disk stamper, and an optical disk manufactured using the stamper.

[0002]

2. Description of the Related Art A conventional mastering process will be described with reference to FIG.

[0005] In FIG. 5A, reference numeral 31 denotes a glass substrate on which a positive type photoresist is applied to form a resist layer 32. As shown in FIG. The recording lens 4 squeezes to a submicron size and exposes. Next, as shown in FIG. 5C, a developing solution is applied from a nozzle 33 onto the glass substrate 31 to remove the above-described exposed portions by etching. It is formed on the resist layer 32. After that, the glass substrate 31 is heated by baking to stabilize the film of the photoresist layer 32 (FIG. 5D). Next, the photoresist layer 32
A metal conductive film 35 is formed on the substrate by sputtering or the like (FIG. 5E). Thereafter, nickel plating is performed using the metal conductive film 35 as an electrode to form the metal conductive film 3.
Then, a nickel thick film 36 having a thickness of about 0.3 mm is formed on the substrate 5 (FIG. 5F). A replica of the pit on the photoresist layer is formed on the nickel thick film 36.

As shown in FIG. 5 (G), the nickel thick film 36 is peeled off from the glass disk 31, the back surface is polished, and the inner and outer diameters are punched to fit a molding machine, thereby completing a master disk of an optical disk, ie, a stamper. I was

[0005]

As described above, the mastering process for producing a stamper includes chemical processing steps such as development and electroforming. In general, in a chemical treatment process, if the production environment such as chemicals, equipment, temperature, and humidity used in the chemical treatment process is not properly controlled, the quality varies and the yield decreases. Furthermore, according to the inventor's experience, the wet process as described above is very likely to cause defects on the stamper. that is,
This is because most surface foreign matter and stains are attached or generated when the stamper is dried from the wet state. In particular, as the density of the optical disk increases, the above-mentioned pit size becomes finer to a submicron size, and even a small stain or a small amount of foreign matter adheres to the stamper, and the stamper becomes defective.

Therefore, in the conventional process, the pits are formed in a chemical solution. In other words, pits are formed on the surface of the resist layer in the developing solution, and nickel signal protrusions are formed along the pits in the plating solution. Therefore, it is difficult to control the cleanliness, and foreign substances are easily attached. .

In addition, pits (depressions) formed on a photoresist layer on a glass disk by exposure and development are transferred as projections (bumps) to a nickel metal plate by electroforming to form a stamper. Therefore, the number of processes is large, and the defects generated during the processes have led to a decrease in quality and yield. In addition, there are disadvantages such as high equipment costs and manufacturing material costs.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and it is easy to control the degree of cleanliness, it is possible to reduce the adhesion of foreign substances and the like, and it is not necessary to carry out steps such as electroforming. Direct dry mastering stampers for optical discs, optical discs that can reduce the number of stamper manufacturing steps and improve quality and productivity by directly dry-etching substrates such as metals and ceramics An object of the present invention is to provide a direct dry mastering method and apparatus for a stamper, and an optical disc manufactured using the stamper.

[0009]

In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, a substrate on which a negative type photoresist resist layer is formed and coated is rotated, and the surface of the rotating substrate is exposed to a laser beam modulated by a signal and focused by a recording lens. To form exposed portions and unexposed portions, and then perform heat treatment, development by a dry process, etching by a dry process, and resist removal by a dry process continuously to form signal protrusions on the surface of the substrate. In addition, the present invention provides a direct dry mastering method for an optical disk stamper, which comprises manufacturing the optical disk stamper by processing the substrate to a stamper size suitable for a mold of an optical disk molding machine.

According to a second aspect of the present invention, a substrate on which a resist layer of a negative type resist is formed and applied and processed into a stamper size suitable for a mold of an optical disk molding machine is rotated to rotate the surface of the substrate. The exposed portion and the unexposed portion are formed by exposing the laser beam which has been signal-modulated and narrowed down by the recording lens, and then subjected to a heat treatment, followed by a dry process development, a dry process etching, and a dry process resist removal. Thus, there is provided a direct dry mastering method for an optical disk stamper, which comprises manufacturing a stamper for an optical disk.

According to a third aspect of the present invention, the heat treatment after the exposure is performed by using an organic sulfur such as hexamethyldisilazane.
The direct dry mastering method for an optical disk stamper according to the first or second aspect, performed in an i-gas atmosphere.

According to a fourth aspect of the present invention, there is provided the direct stamper for an optical disk according to the first or second aspect, wherein the steps of developing, etching and removing the resist are performed in the same chamber by changing only the reaction gas. Provides a dry mastering method.

According to a fifth aspect of the present invention, the stamper substrate having the negative type resist layer on the surface thereof but coated thereon is made of nickel, chromium, aluminum, titanium, cobalt, iron, molybdenum, tungsten, boron, copper And a direct dry mastering method for a stamper for an optical disc according to any one of the first to fourth aspects, wherein the stamper is made of a material containing at least one of tantalum as a main component.

According to a sixth aspect of the present invention, the stamper substrate having the negative type resist layer on the surface but coated thereon is made of Si or a silicon compound such as SiO ₂ or SiC. The present invention provides a direct dry mastering method for an optical disk stamper according to any one of the above aspects.

According to a seventh aspect of the present invention, there is provided the optical disc according to any one of the first to fourth aspects, wherein the stamper substrate having the negative type resist layer on the surface thereof but coated thereon is formed of glass. To provide a direct dry mastering method for stampers.

According to an eighth aspect of the present invention, the stamper substrate having the negative type resist layer on the surface thereof but coated thereon is formed of any one of the first to fourth layers formed of a material containing carbon as a main component. The present invention provides a direct dry mastering method for a stamper for an optical disc according to one of the aspects.

According to a ninth aspect of the present invention, the stamper substrate having the negative type resist layer on its surface, which is coated, comprises: a dry etching layer, a titanium nitride, titanium oxide, tantalum, tungsten Direct dry mastering method for an optical disk stamper according to any one of the first to eighth aspects, having a second layer formed of, for example, chromium, molybdenum, cobalt, boron, nickel phosphorus, nickel boron, or nickel cobalt. I will provide a.

According to a tenth aspect of the present invention, the stamper substrate includes a base layer and a dry etching layer which is disposed on the base layer and partially removed by dry etching to form the signal protrusion. The direct dry mastering method for an optical disk stamper according to the ninth aspect, wherein the second layer dry-etched layer provided on the surface of the layer has a thickness equal to a desired etching depth in the etching. .

According to an eleventh aspect of the present invention, a rotating device for rotating a substrate stamper substrate coated with a negative type photoresist having a resist layer on its surface, and a signal modulated signal on the rotating substrate stamper substrate surface. An exposure device that forms an exposed portion and an unexposed portion by exposing the laser beam focused by the recording lens to form an exposed portion and an unexposed portion, and then sequentially performs heat treatment, development by a dry process, etching by a dry process, and resist removal by a dry process. A processing device for forming a signal protrusion on the surface of the substrate stamper substrate, and a processing device for processing the substrate stamper substrate to a stamper size suitable for a mold of an optical disk molding machine to produce a stamper for an optical disk. Direct drying of a stamper for optical discs characterized in that To provide a static ring device.

According to a twelfth aspect of the present invention, a rotation is performed to rotate a substrate stamper substrate having a resist layer of a negative type resist on its surface and coated and processed into a stamper size suitable for a mold of an optical disk molding machine. An exposure apparatus that exposes a laser beam focused on a surface of the rotating substrate stamper substrate by a recording lens and forms an exposed portion and an unexposed portion, and then performs a heating process and a dry process. And a processing device for producing a stamper of an optical disc by performing development by a dry process, etching by a dry process, and removing a resist by a dry process, to provide a direct dry mastering apparatus for a stamper for an optical disc.

According to a thirteenth aspect of the present invention, in the eleventh or twelfth aspect, the heat treatment after the exposure is performed in an organic Si gas atmosphere such as hexamethyldisilazane. And a direct dry mastering apparatus for the optical disc stamper described above.

According to a fourteenth aspect of the present invention, in the above-mentioned processing apparatus, the optical disc according to the eleventh or twelfth aspect, wherein the steps of developing, etching, and removing the resist are performed in the same chamber by changing only the reaction gas. To provide a direct dry mastering device for stampers.

According to a fifteenth aspect of the present invention, the substrate stamper substrate having the negative type resist layer on the surface but coated thereon is made of nickel, chromium, aluminum,
Direct drying of the stamper for an optical disc according to any one of the eleventh to fourteenth aspects, wherein the stamper is formed from a material containing at least one of titanium, cobalt, iron, molybdenum, tungsten, boron, copper, and tantalum as a main component. Provide a mastering device.

According to a sixteenth aspect of the present invention, the substrate on which the negative type resist is coated with the stamper substrate having a layer on the surface is formed of Si or a silicon compound such as SiO ₂ or SiC. The present invention provides a direct dry mastering device for a stamper for an optical disc according to any one of the above aspects.

According to a seventeenth aspect of the present invention, the substrate to which the stamper substrate having the negative type resist layer on the surface is applied is formed of glass 11 to 11
A direct dry mastering apparatus for an optical disk stamper according to any one of the fourteenth aspects.

According to an eighteenth aspect of the present invention, the substrate to which the stamper substrate having the negative type resist layer on its surface is applied is any one of the first to eleventh to fourteenth to fourteenth materials formed from a material containing carbon as a main component. According to another aspect of the present invention, there is provided a direct dry mastering apparatus for an optical disk stamper.

According to a nineteenth aspect of the present invention, the substrate stamper substrate having the negative type resist layer on the surface but coated thereon is partially removed by dry etching which is disposed on the base layer and disposed on the base layer. The dry etching layer has a two-layer structure in which the signal projections are formed. The dry etching layer has a surface on which titanium nitride, titanium oxide, tantalum, tungsten, chromium,
A direct dry mastering apparatus for an optical disk stamper according to any one of the first to eighteenth aspects, having a second layer formed of molybdenum, cobalt, boron, nickel phosphorus, nickel boron, nickel cobalt, or the like. .

According to a twentieth aspect of the present invention, the substrate stamper substrate includes a base layer and a dry etching layer disposed on the base layer and partially removed by dry etching to form the signal protrusion. It has a two-layer structure,
The direct dry mastering apparatus for a stamper for an optical disc according to the nineteenth aspect, wherein a thickness of the second layer dry etching layer provided on the surface of the stamper is equal to a desired etching depth in the etching.

According to the twenty-first aspect of the present invention, the width or length of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is smaller than the width or length of the signal pit of the optical disk. A direct dry mastering method for an optical disk stamper according to any one of the first to tenth aspects, wherein the length dimension is increased.

According to the twenty-second aspect of the present invention, the width or length of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is smaller than the width or length of the signal pit of the optical disk. A direct dry mastering apparatus for an optical disk stamper according to any one of the first to nineteenth aspects, wherein the length dimension is increased.

According to a twenty-third aspect of the present invention, a rotating stamper substrate having a resist layer on its surface is exposed to a signal-modulated laser beam, and the resist layer on the stamper substrate is heated and then developed. The exposed portion or the unexposed portion of the resist layer is removed to form a signal protrusion forming protrusion on the resist layer, and the signal protrusion forming mask is formed on the resist layer on which the signal protrusion forming protrusion is formed. A signal master is formed on the stamper substrate by dry etching, and the stamper substrate itself on which the signal protrusion is formed is used as a stamper in a direct mastering stamper used for molding an optical disc.
An optical disc stamper in which the width or length of a signal projection forming protrusion of a resist formed on the stamper substrate after the development is larger than the width or length of a signal pit of the optical disc. To provide a direct dry mastering method.

According to a twenty-fourth aspect of the present invention, the inclination angle of the side wall of the projection for forming a signal projection of the resist formed on the stamper substrate after the development is compared with the inclination angle of the side wall of the signal pit of the optical disk. 21. The direct dry mastering method for an optical disk stamper according to the twenty-first or twenty-third aspect, wherein the angles are equal or steeper.

According to a twenty-fifth aspect of the present invention, the width or length of the signal projection forming protrusion of the resist is set to the width of the signal pit or the length of the signal pit of the optical disk. The direct dry mastering method for an optical disk stamper according to the twenty-first, twenty-third, or twenty-fourth aspect, wherein the stamper substrate is at least increased by a value inversely proportional to the selectivity at the time of the dry etching.

According to a twenty-sixth aspect of the present invention, the inclination angle of the side wall of the signal projection forming protrusion of the resist is set to be equal to the inclination angle of the side wall of the signal pit of the optical disk. A direct dry mastering method for a stamper for an optical disc according to any one of the twenty-first and twenty-third aspects wherein at least the value is inversely proportional to the selectivity at the time of dry etching.

According to a twenty-seventh aspect of the present invention, the time width of the recording signal pulse of the laser beam is set so that the selectivity of the resist and the stamper substrate at the time of the dry etching is made longer than the time required for the signal pit length of the optical disk. The 21 st exposed at least longer by a value inversely proportional to
23. A direct dry mastering method for a stamper for an optical disk according to any one of 23 to 26.

According to a twenty-eighth aspect of the present invention, there is provided an optical disc stamper manufactured by the direct dry mastering method for an optical disc stamper according to any one of the twenty-first and twenty-third aspects.

According to a twenty-ninth aspect of the present invention, a rotating stamper substrate having a resist layer on its surface is exposed to a signal-modulated laser beam to heat-treat the resist layer on the stamper substrate. Removing the exposed or unexposed portions of the resist layer by development to form signal protrusion forming protrusions on the resist layer, and forming the signal layer on which the signal protrusion forming protrusions are formed for signal protrusion formation. In the stamper of direct dry mastering for an optical disc, a signal projection is formed on the stamper substrate by dry etching using a mask, and the stamper substrate itself on which the signal projection is formed is used as a stamper for molding an optical disc. Formed on the stamper substrate after the development, rather than the width or length dimensions of the pits Providing width or length stamper large size disc for direct dry mastering signal protrusion forming convex part of the resist.

According to a thirtieth aspect of the present invention, there is provided an optical disc manufactured by using the direct dry mastering stamper according to the twenty-eighth or twenty-ninth aspect.

[0040]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) A direct dry mastering method for an optical disk stamper according to a first embodiment of the present invention will be described with reference to FIG.

In the direct dry mastering method, a stamper substrate on which a negative type photoresist for dry development is applied and a resist layer is formed is rotated,
On the surface of the rotating stamper substrate, an exposed portion and an unexposed portion are formed by exposing a laser beam which is signal-modulated and narrowed by a recording lens, and thereafter, heat treatment, development by a dry process, etching by a dry process,
Continuously remove resist by dry process,
After forming signal projections on the surface of the stamper substrate, the stamper substrate is processed into a stamper size suitable for a mold of an optical disk molding machine to produce a stamper for an optical disk. This will be described with reference to FIG.

First, a negative type resist for dry development is applied to a stamper substrate 1 for a stamper to form a resist layer 2. FIG. 1A shows this state.

Next, a signal is recorded on the stamper substrate 1 of FIG. 1A by a laser beam recorder. Although not shown here, a laser beam recorder modulates a laser beam with a desired signal and exposes the laser beam along the radial direction of the stamper substrate 1;
And a rotation driving device 101 for rotating the rotation at a desired number of rotations. In FIG. 1B, using the optical system 100,
After the signal-modulated laser beam 3 and the laser beam 3 are reduced to a submicron size, the rotation driving device 10
1 shows a recording lens 4 for exposing a resist layer 2 on the stamper substrate 1 rotated and driven by 1 to form an exposed portion and a non-exposed portion.

Next, the stamper substrate 1 subjected to the signal exposure is annealed by heating in an oven or the like.
FIG. 1 (C) shows the stamper substrate 1 after annealing by heat treatment. In this heat treatment step, 1
A heat treatment at 30 to 150 ° C. is performed for about 30 minutes. By this heat treatment, rearrangement of the polymer chains is caused, and the etching resistance of the resist layer 2 can be improved.

Next, development by a dry process is performed,
The exposed portion on the stamper substrate 1 is left, and only the unexposed portion is removed. FIG. 1D shows the stamper substrate 1 after the dry development. The unexposed portion of the stamper substrate 1 is removed, and only the exposed portion remains as the projection 5 for signal projection formation. Dry development is performed by oxygen plasma.
One of such negative resists that can be dry-developed is polymethylisopropenyl ketone (PMI).
A compound obtained by mixing a bisazide compound with PK) is known.

Next, the projection 5 for forming a signal projection is formed into a signal projection shape.
Etching by dry process
That is, dry etching is performed. FIG.
The stamper substrate 1 after ching is shown. 5A is etching
The projection for forming a signal projection later is formed on the stamper substrate 1.
The resulting signal protrusion is shown. Used for etching
The most suitable gas is selected by the stamper substrate 1.
However, generally CF _Four, NF_Three, BCl_Three-Cl_Three, Cl
_ThreeOr CCl_FourAre used.

Next, the resist is removed by a dry process. FIG. 1F shows a resist 5A formed by ashing.
Of the master stamper has been removed, that is, a state in which a so-called master stamper has been completed. Ashing is
Oxygen radicals in the oxygen plasma cause the resist to become CO ₂
And H ₂ O.

After the removal of the resist, the stamper substrate 1 is processed to have a predetermined inner and outer diameter so that the stamper substrate 1 can be mounted on a mold of an optical disk molding machine, thereby completing the stamper. The stamper can be mounted on a mold of an optical disc molding machine, and a large amount of duplicate optical discs can be produced using the mold.

As described above, according to the first embodiment of the present invention, the stamper is manufactured in a small number of steps without performing the wet treatment, that is, without wetting the stamper substrate with the cleaning liquid and the chemical after the resist is applied. can do.

(Second Embodiment) FIG. 2 shows a direct dry mastering method for an optical disk stamper according to a second embodiment of the present invention.

This direct dry mastering method differs from the first embodiment in that the inner diameter or outer diameter is processed to a stamper size suitable for a mold of an optical disk molding machine before applying a resist to a stamper substrate. is there. That is, the direct dry mastering method involves rotating a stamper substrate coated with a negative type resist and processed to a stamper size suitable for a mold of an optical disc molding machine, and a signal is modulated on the surface of the rotating stamper substrate to form a recording lens. The exposed laser beam is exposed to light to form an exposed portion and an unexposed portion, and then subjected to a heat treatment, followed by development by a dry process, etching by a dry process, and removal of a resist by a dry process to obtain a stamper for an optical disc. Is made. This will be described with reference to FIG.

First, a negative type resist for dry development is applied to a stamper substrate for a stamper to form a resist layer 12. However, in FIG.
Is a stamper substrate similar to the stamper substrate 1 in FIG. 1, but has already been processed into a stamper size suitable for a mold of an optical disk molding machine. This processing may be processing of the inner diameter or the outer diameter or both. 1
Reference numeral 2 denotes a negative type resist layer. The stamper size processing may be performed after resist application.

Next, similarly to FIG. 1B of the first embodiment, a signal is recorded on the stamper substrate 11 by a laser beam recorder. FIG. 2B shows a state in which the same exposure operation as that in FIG. 1B is performed.

Next, similarly to FIG. 1C of the first embodiment, the stamper substrate 11 subjected to the signal exposure is annealed by heating in an oven or the like. FIG. 2 (C)
Shows a state in which the same heat treatment operation as in FIG. 1C is performed.

Next, in the same manner as in FIG. 1D of the first embodiment, development is performed by a dry process, and only the unexposed portions are removed while leaving the exposed portions on the stamper substrate 11. FIG. 2D shows the stamper substrate 11 after dry development.
This shows a state in which the signal projection forming projections 15 of the resist layer 12 remain.

Next, similarly to FIG. 1E of the first embodiment, etching by a dry process, that is, dry etching is performed using the signal projection forming protrusions 15 as a signal projection forming mask. FIG. 2E shows the stamper substrate 11 after dry etching, in which the resist layer 15 serving as a mask remains as 15A. Reference numeral 16 denotes a signal projection formed on the stamper substrate 11.

Next, similarly to FIG. 1F of the first embodiment, the resist is removed by a dry process. FIG.
(F) shows the stamper substrate 11 after plasma ashing.
Since it has already been processed to the stamper size, it can be mounted as it is on the optical disk molding machine as it is.

As described above, according to the second embodiment,
If there is one processing facility for finishing the stamper substrate 11 in the state of FIG. 2 (A), other disk factories that perform the subsequent processing will manufacture the stamper if they have the facilities of FIG. 2 (B) or later. be able to. That is, only an optical system including a laser beam recorder for writing a signal, an oven for heat treatment, and processing equipment for performing dry development, etching, and ashing may be used. Unlike a conventional mastering factory, each factory does not need to own expensive facilities such as a pure water production facility and a waste liquid treatment facility for used chemicals and cleaning liquids.

(Third Embodiment) Next, FIG. 3 shows a direct dry mastering method for an optical disk stamper according to a third embodiment of the present invention.

In the direct dry mastering method, a dry etching layer is provided on the surface of the stamper substrate on which the negative type resist for dry development is applied to form a resist layer.

In FIG. 3A, reference numeral 21a denotes a stamper substrate main body which is a base layer, and 21b denotes a stamper substrate main body 21.
The dry etching layer is formed on the substrate a, and the stamper substrate 21 is composed of the base layer 21a and the dry etching layer 21b. Here, the thickness of the dry etching layer 21b is adjusted to the height of the signal projection to be finally formed. Assuming that the refractive index of an optical disk made of a synthetic resin such as polycarbonate after molding is n, and the wavelength of a reproduction laser beam for reproducing (reading) the optical disk is λ, the height of the signal projection is λ / (4 · n). It is common. Suitable materials for the dry etching layer 21b are titanium nitride, titanium oxide, tantalum, tungsten, chromium, molybdenum, cobalt, boron, nickel phosphorus, nickel boron, nickel cobalt and the like. These materials can be firmly formed on a nickel stamper substrate by ion plating, sputtering, vacuum deposition, electroforming, electroless plating, or the like. In this case, the hardness is high and the stamper can be sufficiently used.

As shown in FIG. 1A of the first embodiment or FIG. 2A of the second embodiment, a dry development layer is formed on the dry etching layer 21b on the stamper substrate body 21a. The resist layer 22 is formed by applying a negative type resist.

Next, similarly to FIG. 1B of the first embodiment or FIG. 2B of the second embodiment, a signal is applied to the dry etching layer 21b of the stamper substrate main body 21a by a laser beam recorder. Record. FIG. 3B is FIG.
This shows a state in which the same exposure operation as that shown in FIG.

Next, similarly to FIG. 1C of the first embodiment or FIG. 2C of the second embodiment, the signal-exposed stamper substrate main body 21a and the dry etching layer 21b are placed in an oven or the like. To perform annealing. FIG. 3C illustrates a state in which the same heat treatment operation as that in FIG. 2C is performed.

Next, as in the case of FIG. 1D of the first embodiment or FIG. 2D of the second embodiment, development by a dry process is performed to form a layer on the dry etching layer 21b of the stamper substrate 21a. The exposed portion is left, and only the unexposed portion is removed. FIG. 3D shows the stamper substrate 2 after dry development.
1a and the dry etching layer 21b, showing a state where the signal projection forming projections 25 of the resist layer 22 remain.

Next, similarly to FIG. 1E of the first embodiment or FIG. 2E of the second embodiment, a dry process is performed using the signal projection forming protrusions 25 as a signal projection forming mask. , That is, dry etching is performed. FIG. 3E shows the stamper substrate main body 21a after the dry etching.
5A shows the remaining state. Reference numeral 26 denotes a signal protrusion formed on the dry etching layer 21b. Here, the height of the signal projection 26 corresponds to the thickness of the dry etching layer 21b. Here, the reason why the thickness of the dry etching layer 21b is adjusted to the desired height of the signal protrusion 26 is to accurately detect the end point in the etching.

Next, as in FIG. 1F of the first embodiment or FIG. 2F of the second embodiment, the resist is removed by a dry process. After the ashing, the stamper substrate main body 21a is a master in which the signal projections 26 are formed on the dry etching layer 21b on the stamper substrate main body 21a as the base layer. When the same steps as in the first embodiment have been performed, the inner and outer diameters of this master are processed so as to match the mold of the optical disk molding machine, and the stamper is completed. Further, as described in FIG. 2, in the third embodiment, the stamper may be machined from the beginning. That is, when the same steps as those in the second embodiment have been performed, since the stamper is already processed into the stamper size, it can be mounted as it is on the optical disc molding machine as it is.

(Fourth Embodiment) Next, FIG. 4 can be used when the direct dry mastering method for an optical disk stamper according to the first to third embodiments of the present invention and a fifth embodiment described later. FIG. 11 is a schematic view of a parallel plate type etching apparatus for reactive ion etching in a direct dry mastering apparatus for an optical disk stamper according to a fourth embodiment of the present invention.

In FIG. 4, reference numeral 40 denotes chambers serving as various processing chambers, reference numeral 41 denotes an upper electrode, reference numeral 42 denotes a lower electrode, and reference numeral 43 denotes a stamper substrate mounted on the lower electrode 42. 6, FIG. 9, FIG. 9, FIG. 2, FIG.
21 corresponds to this. 44 is a matching device for the lower electrode, 4
Reference numeral 5 denotes a high-frequency power supply connected to the lower electrode 42 via a matching device 44. 46 is an exhaust pump for exhausting the inside of the chamber 40, 47 is a reaction gas supply pipe for supplying a reaction gas into the chamber 40, and 48 is a flow control valve for adjusting the supply flow rate of the reaction gas. The reaction gas is of three types: a gas for dry development, a gas for etching, and a gas for ashing. Various reaction gases are connected to a reaction gas supply pipe 47 from a supply tank (not shown) via pipes 49, 50, 51, and via flow rate control valves 48, respectively. 52 is an optical fiber for detecting the end point of the etching of the stamper substrate in the chamber 40, 53 is an end point detecting device connected to the optical fiber 52, and 54 is a control device of the etching device. The end point of the etching is input to the end point detector 53 via the optical fiber 52, and the state of the plasma is automatically monitored by the end point detector 53. Here, the emission spectrum of the plasma is based on radicals and ions such as an etching gas, a decomposition product thereof, and a reaction product. That is, FIG.
In the etching step (E), the etching proceeds on the dry etching layer 21b, and when the base layer 21a serving as the stamper substrate main body appears and the etching of the stamper substrate main body 21a starts, the emission spectrum of the plasma changes. This change in the emission spectrum is detected by the end point detection device 53, and an instruction to stop the etching is given to the control device 54. Thereby, the amount of etching can be controlled with the accuracy of the film thickness of the dry etching layer 21b. this is,
This is because, in general, the control of the film adhesion amount can be controlled more accurately than the control of the etching amount.

In the above description, the dry etching layer 21b
Has been described only when the thickness of the signal protrusion 26 is equal to the height of the signal protrusion 26, but the height of the signal protrusion 26 is
There is an effect even when the thickness is less than the thickness. That is, as described above, the height of the signal protrusion 26 may be λ / (4 · n), where λ is the reproducing laser beam wavelength for reproducing the optical disk and n is the refractive index of the optical disk.
The value is about 50 nm. Therefore, if the dry etching layer 21b has a thickness of 1 micron, the signal projection 26 can be sufficiently formed. Since the whole has a thickness of 0.3 mm, it can be considered that the stamper is almost mechanically and thermodynamically a characteristic of the stamper substrate. That is, a material having optimal characteristics according to the molding conditions can be selected as the stamper substrate. On the other hand, an optimal material can be selected for the dry etching layer 21b in consideration of the etching characteristics.

In the etching apparatus shown in FIG.
In addition to performing the etching step, exhaust is performed by an exhaust pump 46, and a valve 48 is opened and closed to open a pipe 49,
By supplying a desired reaction gas from one of 50 and 51 into the chamber 40, only the reaction gas supplied into the chamber 40 is replaced, and the processes of dry development, etching, and ashing can be continuously performed. It is possible. As a result, three processes can be performed by one apparatus, and the amount of capital investment can be significantly reduced. In addition, since the handling of the stamper is eliminated between these steps, the occurrence of defects such as adhesion of foreign substances can be prevented, and the yield can be greatly improved. In addition, the production time can be reduced.

The etching of the present invention is not limited to reactive ion etching, but may be sputter etching or ion beam etching.

In each of the above embodiments, a dry-developable resist obtained by mixing a bisazide compound with polymethylisopropenyl ketone (PMIPK) has been described. However, the present invention is not limited to this. The present invention can also be applied to a resist capable of forming a resist and a method thereof. One example is a method in which an exposed portion is converted into a silyl (silicon compound), the resistance to oxygen plasma is increased, and selective development is performed. In one example of silylation, the heat treatment after exposure is H
This is performed in an organic gas atmosphere such as MDS (hexamethyldisilazane). Also in this case, the heating temperature is 130 to 150.
It is about ° C. By baking before silylation, unexposed portions are cross-linked to suppress diffusion of HMDS, whereas HMDS is easily diffused and silylated in exposed portions. Since the silylated portion has high resistance to oxygen plasma,
In the subsequent dry development, it can be left as a projection for forming a signal projection.

The stamper substrate for the stamper or the stamper substrate main body indicated by 1 in FIG. 1, 11 in FIG. 2 and 21a in FIG. 3 is nickel, chromium, aluminum, titanium, cobalt, iron, molybdenum, tungsten, boron. , Copper, tantalum, or the like, and a material containing at least one of tantalum as a main component can be used, and can be manufactured at low cost by mass production. The metal stamper substrate or the stamper substrate body can be easily manufactured to a thickness of about 0.3 mm, which is the thickness of a nickel stamper currently used (that is, manufactured by conventional electroforming). It can be used as it is for the mold of the current molding machine. Many of these have thermal conductivity close to that of a conventional nickel stamper and can be molded under the same molding conditions. Therefore, it can be easily replaced with a current stamper.

In another embodiment of the present invention, a stamper substrate for a stamper or a stamper substrate body
i or a silicon compound such as SiO ₂ or SiC can be used. These have excellent workability in etching and are relatively easily available because they are widely used in the semiconductor field. Since these silicon stamper substrates are thicker than the current nickel stampers, it is necessary to adjust them by inserting a spacer in a mold.

In another embodiment, glass can be used as the stamper substrate or the stamper substrate main body. Considering the processability of etching, quartz glass is preferred.

In still another embodiment, a material containing carbon as a main component can be used for the stamper substrates 1 and 11 or the stamper substrate main body 21a. A material obtained by sintering carbon powder into a plate shape can be used.

As described above, according to each of the above embodiments of the present invention, after a photoresist is applied to the stamper substrates 1, 11, 21 to form a resist layer, pit formation in a wet manner by a chemical agent, The stamper can be completed without cleaning with pure water. In the field of semiconductors, research on negative-type dry developing resists has been conducted for a long time.However, when using dry-type resists, the disadvantages of negative-type resists, which previously deteriorated the resolution due to swelling of the resist due to contact with the developing solution, have been improved. There is also the advantage of being done.

According to the above configuration, when such a resist for dry development is used, the signal projections 6, 16, 26 having unevenness are formed on the resist layer regardless of the conventional wet development.
Can be formed. Also, instead of producing a stamper by electroplating, the stamper substrates 1, 11,
If the method of forming pits directly on the substrate 21 is adopted, a stamper can be manufactured without performing conventional electroforming. Conventionally, using a positive type resist, exposure,
The pits (depressions) formed by development were used to form replicas by electroforming to obtain opposite convex protrusions. However, if it is a negative type resist as described above,
The exposed portion of the laser beam remains after development, and serves as a mask for etching. That is, portions other than the portion are removed by etching, so that the projections 6, 16, and 26 can be formed directly on the stamper substrates 1, 11, and 21. Therefore, according to each of the above embodiments, the pits can be formed in a vacuum without depending on the wet chemical treatment, so that the cleanness can be easily controlled, the adhesion of foreign matter and the like is recommended, and the process yield is reduced. Can be improved.

(Fifth Embodiment) A direct mastering method for an optical disk stamper according to a fifth embodiment of the present invention has the same basic steps as in the first embodiment shown in FIG. The projections 5 for use on the stamper substrate 1 and the signal projections 6 on the stamper substrate 1 have different shapes, so that it is possible to prevent the reproduction characteristics of the optical disk from deteriorating. Although the fifth embodiment can be applied to the direct mastering method of the optical disc stamper of the second and third embodiments, for simplicity, the direct mastering method of the optical disc stamper of the first embodiment will be described. A description will be given based on the mastering method.

That is, in the direct mastering method shown in FIGS. 1A to 1F, a projection 5 for forming a signal projection of a resist is formed by exposure and development, and the stamper substrate 1 is etched using the projection as a mask. When the signal protrusion 6 is formed, the signal protrusion forming protrusion 5 of the resist and the signal protrusion 6 of the stamper substrate 1 have different shapes, which may deteriorate the reproduction characteristics of the optical disk.

FIG. 6 shows signal pits 160 formed on the optical disk after molding using the stamper. 6 by L ₁ is the length of the opening of the pit 160, L ₂ is the length of the bottom of the pit 160, W ₁ is the width of the opening of the pit 160, W ₂ is the width of the bottom of the pit 160, d pit 16
A depth of 0, θ ₁ is an inclination angle of the pit 160 with respect to the vertical direction in the front-rear direction, and θ ₂ is an inclination angle of the side wall of the pit 160 with respect to the vertical direction. In an actual optical disk, such pits 160 are spirally connected. When the spot of the reproduction laser beam focused to the submicron size irradiates the pit 160, the reflected light becomes the pit 1
It is modulated by diffraction and interference by 60, which is detected as a reproduced signal. Therefore, the characteristic of the reproduced signal is pit 1
60 greatly depends on the shape. Therefore, the shape of the signal projection 6 of the stamper needs to be processed into a shape that optimizes the reproduction characteristics. In an optical disc production factory, the production of the signal projections 6 of the stamper must be controlled so as to always maintain the optimum shape so that the stampers can be produced without variation in the shape of the signal projections 6 of the stamper.

FIG. 7A is a cross-sectional view of the signal projection forming protrusions 5 of the resist formed on the stamper substrate 1 as viewed from the track direction of the optical disk. FIG. 7B shows a cross-sectional view of the signal protrusion 6 formed on the stamper substrate 1 after etching in a form closer to actuality. In FIGS. 1 to 3, for convenience, the signal-projection-forming projections 5 are shown in a rectangular cross section, but they are actually substantially trapezoidal in shape. When the stamper substrate 1 is etched by a dry process such as reactive ion etching or ion beam etching using the signal projection forming protrusions 5 of the resist as a signal projection forming mask, the signal projection forming projections functioning as signal projection forming masks. The end of the portion 5 is also shaved, and the size of the signal protrusion 6 formed on the stamper substrate 1 is
It is smaller than the signal projection forming protrusions 5 of the resist.

As shown in FIG. 7A, the width of the upper surface of the signal projection forming protrusion 5 of the resist is W ₆ , the width of the bottom of the signal projection forming protrusion 5 is W ₅ , As shown in FIG. 7 (B), the width of the upper surface of the signal projection 6 after etching and ashing is W ₄ , and the width of the bottom of the signal projection 6 is θ ₆ , as shown in FIG. Is W ₃ and the inclination angle of the side wall of the signal protrusion 6 is θ ₄ , W ₅ ≧ W ₃ and W ₆ ≧
W ₄ , and θ ₆ ≦ θ ₄ . Also, since the transfer of the signal protrusions 6 by the molding resin is not complete even during molding of the optical disc, the inclination angle of the pit 160 of the optical disc is further increased.
Relationship between the _fourth angle of inclination of the side wall theta angle of inclination theta ₂ and the signal projection 6 against the vertical direction in the side wall of the pit 160 of FIG. 6,
Generally, there is a tendency that θ ₄ ≦ θ ₂ .

As described above, in the direct mastering method by the dry process, the shape of the pit 160 of the optical disk which directly affects the signal characteristics is not the same as the shape of the signal projection forming protrusion 5 of the resist. The yield has been reduced in the production process.

The difference between the shape of the projections 5 for forming signal protrusions of the resist and the shape of the pits 160 of the optical disk is that the end of the convex portion of the resist mask is retreated (decreased) at the time of etching and the transfer is poor at the time of molding the optical disk. However, if the etching resistance of the resist, the process conditions for dry etching, and the molding conditions are always kept constant, the difference between the two can be kept within a certain value.

On the other hand, the shape of the signal projection forming protrusions 5 of the resist is determined by the sensitivity of the resist, the beam shape (beam profile) of the recording laser beam, the recording signal, and the developing conditions. Of these factors, the factors that can be easily fine-tuned are the beam shape (beam profile, ie, laser beam intensity, beam diameter incident on the recording lens, etc.) of the recording laser beam, and the recording time (duty of the recording signal, etc.). .

Therefore, in the fifth embodiment of the present invention, by setting the beam shape of the recording laser beam and the setting of the recording signal,
The projections 5 for forming signal projections of the resist are formed in anticipation of a known dimensional difference in advance, so that the pit shape of the optical disk finally formed after the optical disk is formed is made ideal.

Particularly, in the process of developing the resist in a dry state, the process can be easily controlled, and the quality in the developing step can be easily controlled to be constant. Therefore, the process is suitable for applying the fifth embodiment of the present invention. It is a short time of 20 to 30 seconds to complete the development in the conventional wet development,
This is because dry development takes 1 to 2 minutes, so that the accuracy of time management is improved. However, it goes without saying that the fifth embodiment can also be applied to a wet development process.

Now, assuming that the signal projection 6 on the stamper substrate 1 shown in FIG. 7B corresponds to the ideal shape of the pit 160 of the optical disk after molding.
The shape of the signal projection forming protrusion 5 of the resist shown in FIG. 4A is determined in consideration of the retreat (reduction) of the protrusion end by etching, and the width W ₅ of the bottom of the signal projection forming protrusion ₅ and the upper surface portion are determined. W ₆
And the inclination angle θ ₆ of the side wall of the signal projection forming protrusion 5 needs to be formed to be relatively small.

FIG. 9 shows the relationship between the beam intensity profile of the recording laser beam and the signal projection forming protrusions 5 of the resist formed after exposure and development. In FIG.
Let P ₀ be the threshold value of the exposure intensity at which the dissolution of the resist starts to be inhibited in the developing step, and P ₁ be the beam intensity when the thickness of the resist layer of the resist constituting the projections 5 for forming signal projections becomes d _0. If the spot of the recording laser beam whose beam profile is a solid line 210 is exposed on the resist layer 2, the shape of the signal projection forming protrusion 5 of the resist remaining on the resist layer 2 after development is as shown in FIG. (B)
Let's say The intersection of the beam intensity P ₁ and the solid line 210 determines the position of the upper surface of the signal projection forming protrusion 5,
The intersection of the exposure intensity threshold value P ₀ and the solid line 210 determines the position of the bottom of the projection 5 for signal projection formation. 9 in FIG.
Is a beam profile when the laser beam intensity is reduced. In FIG. 9A, reference numeral 212 denotes a numerical aperture of a recording lens for narrowing a recording laser beam. A. Alternatively, it is a profile when the diameter of the incident beam to the recording lens is reduced.
As described above, when the intensity of the recording laser beam, the numerical aperture of the recording lens, and the incident beam diameter are changed, the beam profile changes, and the intersections of the beam profile and P ₀ and P ₁ change. Can be changed.

The numerical aperture of the recording lens is N.P. A. When the wavelength of the recording laser beam is represented by λ, the beam diameter Φ of the recording laser beam passing through the recording lens at 1 / e ² of the central intensity is:

[0094]

Φ = 0.637λ / (NA)

If the focal length of the recording lens is f and the incident beam diameter is w,

[0096]

## EQU2 ## Φ = 1.27f · (λ / w) According to the above relational expression, by changing the intensity of the recording laser beam and the numerical aperture or the incident beam diameter of the recording lens, the optimum beam diameter for forming the signal projection forming convex portion 5 of the optimum resist is obtained. be able to.

Next, the concept of determining the shape of the signal projection forming protrusion 5 of the resist will be described.

Assuming that the ratio (B / A) of the etching rate A of the resist and the etching rate B of the material of the stamper substrate 1 is a selection ratio α, the projections 5 for signal projection formation in FIG.
Width W ₅ of the bottom of the bottom width W ₃ of the signal projection 6, the width of W ₆ of the upper surface portion of the signal projection-forming convex part 5, the width of the upper surface portion of the signal projection 6 after etching and ashing W _4. The inclination angle of the side wall of the projection 5 for signal projection formation is θ ₆ , and the inclination angle of the side wall of the signal projection 6 after etching and ashing is θ
₄ can be set in the following relationship.

[0099]

[Number 3] _{W 5 = W 3 + k 1} · (1 / α) W 6 = W 4 + k 2 · (1 / α) θ 6 = θ 4 -k 3 · (1 / α) where k _1, k ₂ and k ₃ are constants determined by the etching process conditions, for example, constants determined by the etching rate of each material, the etching gas, the degree of vacuum, and the like. For example, the constants are k ₁ > 0, k ₂ > 0, k ₃ > 0
It is.

As is apparent from the above equation, the width W ₅ of the bottom of the projection 5 for forming the signal projection is more inversely proportional to the selection ratio α than the width W ₃ of the bottom of the signal projection 6 (1 / α). ) And the constant k _1, and the width W ₆ of the upper surface of the signal projection forming protrusion 5 is inversely proportional to the selection ratio α than the width W ₄ of the upper surface of the signal projection 6. At least by the product of the calculated value (1 / α) and the constant k _2, and the signal projection forming protrusion 5
Inclination angle theta ₆ of the side wall of the can than the inclination angle theta ₄ of the side wall of the signal projection 6, to minimize the value of the product of the inverse proportion to the value in the alpha selection ratio (1 / α) and the constant k _3.

FIG. 8A is a cross-sectional view of the signal projection forming projection 5 of the resist viewed from the side in the longitudinal direction.
(B) is a cross-sectional view of the signal projection 6 on the stamper substrate as viewed from the same longitudinal direction. In order to obtain the optimum shape of the signal protrusion 6 for the same reason as described in the section in the track direction of the optical disk in FIG. 7, the length L ₃ of the bottom of the signal protrusion 6 and the length of the upper surface of the signal protrusion 6 are required. L ₄ , when the inclination angle of the front and rear walls of the signal protrusion 6 is θ ₃ , the length L ₅ of the bottom of the signal protrusion formation protrusion 5 of the signal protrusion formation protrusion 5 of the resist, and the signal protrusion formation protrusion The length L ₆ of the upper surface portion ₅ and the inclination angle θ ₅ of the front and rear walls of the signal projection forming protrusion 5 may be set as in the following equations.

[0102]

L ₅ = L ₃ + k ₁ · (1 / α) L ₆ = L ₄ + k ₂ · (1 / α) θ ₅ = θ ₃ -k ₃ · (1 / α) where k ₁ , k ₂ and k ₃ are constants determined by the etching process conditions, and are constants determined by, for example, the etching rate, etching gas, vacuum degree, and the like of each material. K ₁ , k ₂ , and k ₃ are the width W ₅ of the bottom of the projection 5 for forming the signal projection, the width W ₆ of the upper surface of the projection 5 for forming the signal projection, and the projection ₅ for forming the signal projection, respectively. Are the constants used in the equation for obtaining the inclination angle θ ₆ of the side wall of FIG.

As is apparent from the above equation, the length L ₅ of the bottom of the projection 5 for forming the signal projection is more inversely proportional to the selection ratio α than the length L ₃ of the bottom of the signal projection 6 (1). / Α) and the constant k _1, and the length L ₆ of the upper surface portion of the signal projection forming protrusion 5 is larger than the length L ₄ of the upper surface portion of the signal protrusion 6 by a selection ratio. At least the value of the product of the value (1 / α) inversely proportional to α and the constant k ₂ is increased at least, and the inclination angle θ ₅ of the front and rear walls of the projection 5 for signal projection formation is determined by The inclination angle is made smaller than θ ₃ by the product of a value (1 / α) inversely proportional to the selection ratio α and a constant k ₃ .

Next, a method of changing the length L ₅ of the bottom portion and the length L ₆ of the upper surface portion of the signal projection forming protrusion 5 will be described.

FIG. 10A shows the recording signal,
Signal pulse recording laser beam during the time is on t ₀ indicates that it is exposed to. The vertical axis is the axis indicating ON or OFF of the recording signal, and the horizontal axis is the time axis.

The vertical axis in FIG. 10B indicates the signal pulse 2
13 shows the exposure power of the recording laser beam corresponding to 13,
The horizontal axis indicates time. The beam profile indicated by 210 in FIG. 10B is the beam profile 210 in FIG.

The vertical axis of FIG. 10C shows the cumulative exposure of the recording laser beam when the resist layer 2 is exposed to the recording laser beam of the beam profile 210, and the horizontal axis shows time.

FIG. 10D shows a projection 5 for forming a signal projection formed after development as a result of the exposure of the resist layer 2.

When the value of the cumulative exposure amount shown in FIG.
Point _0, that is, the dissolution of the resist described is a threshold value starts to be blocked in FIG. 9, the length of the bottom portion of the signal projection-forming convex part 5 becomes L ₅ in FIG. That is, to change the length of the projection 5 for forming a signal protrusion, the signal pulse 21 shown in FIG.
What is necessary is just to change the time t ₀ of No. 3. This corresponds to changing the ratio of the signal on and off, that is, the duty.

According to the fifth embodiment, as described above, the parameters that can be finely adjusted (for example, the laser beam intensity, the diameter of the incident beam to the recording lens, the duty of the recording signal, etc.) are changed, so that the resist The optimum shape of the signal projection forming protrusion 5 can be obtained. That is, the width or length of the signal projection forming protrusions 5 of the resist formed on the stamper substrate 1 after the development is smaller than the width or length required for the signal pits 160 of the optical disc. In other words, by increasing the size in consideration of the etching process conditions, the retreat (reduction) of the end of the convex portion of the resist mask at the time of etching and the transfer failure at the time of optical disk molding are alleviated. The pit shape of the optical disk formed later can be made closer to the ideal one than before. More specifically, the width or length of the signal projection forming protrusion 5 of the resist is set to the width of the signal pit or the length of the signal pit of the optical disc, and If the value is at least increased by a value inversely proportional to the selectivity at the time of etching, the signal pit 16
The accuracy of the 0 shape can be made higher.

The inclination angle of the side wall of the projection for forming a signal projection of the resist formed on the stamper substrate after the development is equal to the inclination angle of the side wall required for the signal pit of the optical disk, or By making the angle steeper, it is possible to alleviate the retreat (reduction) of the end of the resist mask at the time of etching and the transfer failure at the time of molding the optical disk, and to finally achieve the pit shape of the optical disk that can be finally formed after optical disk molding. Can be made closer to a conventional one. More specifically, with respect to the inclination angle of the signal pit sidewalls of the optical disc, the inclination angle of the sidewalls of the signal projection forming protrusions of the resist is determined by the selectivity of the resist and the stamper substrate during the dry etching. If the value is reduced by an inversely proportional value, the accuracy of the shape of the signal pit 160 due to etching can be increased.

As a specific method for changing the process conditions, the laser beam profile is changed, and the time width of the recording signal pulse 213 of the recording laser beam is set to a value smaller than the time required for the signal pit length of the optical disk. When the recording laser beam is exposed so as to be at least longer by a value inversely proportional to the selectivity α at the time of the dry etching of the stamper substrate 1, the length or width or the inclination angle of the projection 5 for signal projection formation is reduced. Can be changed. Actually, a shape that optimizes the reproduction characteristics of the optical disk after molding is experimentally obtained by changing the above parameters. Therefore, the signal protrusion of the stamper according to the present invention and the pit of the molded optical disk can realize an optimal shape.

The parameters that are finely adjusted on a daily basis include the laser beam intensity, the beam diameter incident on the recording lens, the duty of the recording signal, and the like. It is desirable to constantly monitor and manage the laser beam profile.

In the production of optical disks, development,
It is conceivable that the process conditions of the post-process such as etching and molding slightly move, and the signal pits of the optical disk gradually change. However, according to the method of the present invention,
Since each of the above parameters can be finely adjusted, it is easy to return the signal pits of the optical disk to the optimum values. Further, if each parameter is managed, it is possible to accurately grasp where the subsequent process has changed, so that the process can be reliably managed.

As described above, the stamper according to the present invention,
The mastering method and the optical disc realize a shape that optimizes a reproduction signal and have good quality. Further, the yield can be improved because the process can be easily controlled.

In the above description, the stamper substrate 1 has a single-layer structure. However, as shown in FIG. 3, the stamper substrate 21 having a two-layer structure in which an etching layer 21b is provided on a base layer 21a is also used. It goes without saying that the fifth embodiment of the invention can be applied.

It is to be noted that by appropriately combining any of the above-described various embodiments, the effects of the respective embodiments can be exhibited.

[0118]

(1) Since the pit formation in the conventional mastering process is performed in a chemical solution, that is, in a developing solution, it is difficult to control the cleanness and foreign substances are easily attached. However, according to the present invention, the stamper of the optical disc can be manufactured without wetting the stamper substrate with the cleaning solution and the chemical solution after the resist is applied, and the pits can be formed in a vacuum without depending on the wet chemical treatment. So it ’s easy to manage cleanliness,
Adhesion of foreign matter and the like is recommended, and the process yield can be improved. That is, after the resist is applied to the stamper substrate, there is no need for wet processing such as pure water or chemicals. Therefore, when the stamper substrate is dried after the wet processing, there is no occurrence of surface defects due to stains or foreign matter adhesion, and a high-quality stamper can be produced with high yield.

(2) Further, a pure water apparatus and a waste liquid processing apparatus for wet treatment are not required, and the amount of capital investment can be greatly reduced.

(3) Since the process of the present invention is not a wet process but a dry process, the number of processes can be reduced as compared with the conventional method. In particular, if a stamper substrate that has been processed to the stamper size and the resist has already been applied is used, and dry development, etching, and resist removal are performed in the same chamber, the stamper required for molding can be produced with only three facilities. it can. Therefore, production equipment costs are reduced, and the factory area can be reduced.

(4) Further, the stamper can be manufactured in a short time for the above reasons.

(5) Since the number of steps is reduced, the probability of occurrence of defects such as adhesion of foreign matter and scratches during transport and handling of the stamper substrate is reduced, and the yield can be improved.

(6) The stamper substrate to which the negative type resist is applied is composed mainly of at least one of nickel, chromium, aluminum, titanium, cobalt, iron, molybdenum, tungsten, boron, copper, and tantalum. When the metal stamper substrate is made of the same material as that of the conventional nickel plate manufactured by electroforming, the conventional molding machine can be used without changing the mold. In addition, for the stamper substrate, a nickel-based alloy, a chromium-based alloy, a nickel-chromium alloy, a nickel-cobalt alloy is used, or titanium nitride, titanium oxide, tantalum, tungsten, chromium, molybdenum, cobalt, If a material having a dry etching layer such as boron, nickel phosphorus, nickel boron, nickel cobalt or the like is used, molding can be performed under the same molding conditions as those of a conventional nickel stamper.

(7) On a stamper substrate having a dry etching layer of titanium nitride, titanium oxide, tantalum, tungsten, chromium, molybdenum, nickel phosphorus, nickel boron, nickel cobalt, etc. on the stamper substrate, the dry etching layer If the thickness is made the same as the desired height of the signal protrusion, the end point of the etching can be easily detected by a change in the emission spectrum of the plasma, and the etching accuracy, that is, the height accuracy of the signal pit due to the etching can be increased.

(8) According to the method and apparatus of the present invention,
Since there is no step that requires know-how of processes such as chemical treatment, even inexperienced manufacturers can perform mastering.

(9) Further, since there is no step using a chemical change, the process is stable. (10) The cost for stabilizing the working environment such as temperature and humidity is not required.

(11) Further, if the inner diameter or outer diameter is processed to a stamper size suitable for a mold of an optical disk molding machine before forming a resist on a stamper substrate by coating or the like, a defect will occur in a later step. The probability is reduced, and the yield can be further increased.

(12) The substrate to which the negative type resist is applied is made of Si, SiO ₂ , Si
If it is formed from a silicon compound such as C,
These have excellent workability at the time of etching and are relatively easily available because they are widely used in the semiconductor field. In addition, if the substrate to which the negative type resist is applied is formed of glass, quartz glass is preferable in consideration of etching workability. Furthermore, if the substrate to which the negative type resist is applied is made of a material containing carbon as a main component, a material obtained by sintering carbon powder and solidifying it in a plate shape can be used.

Further, according to the direct dry mastering apparatus for an optical disk stamper of the present invention, a stamper for an optical disk can be manufactured without wetting the stamper substrate with a cleaning solution and a chemical solution after forming the resist.
Also, before forming a resist on the stamper substrate, if the inner diameter or outer diameter is processed to a stamper size suitable for the mold of the optical disc molding machine, the probability of occurrence of defects in the subsequent process is reduced, and the yield is further increased. be able to.

As described above, the present invention reduces the cost of manufacturing a stamper, and enables a stamper with good yield and quality to be produced in a short time even if the stamper has no experience.

In the present invention, by changing parameters that can be finely adjusted (for example, the laser beam intensity, the diameter of the incident beam to the recording lens, the duty of the recording signal, etc.), the optimum projection of the resist for forming the signal protrusion is formed. The shape can be determined. That is, the width or length dimension of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is larger than the width or length dimension required for the signal pits of the optical disc. In other words, by increasing the size in consideration of the etching process conditions, the retreat (decrease) of the end of the convex portion of the resist mask at the time of etching and the transfer failure at the time of molding the optical disk are alleviated.
Finally, the pit shape of the optical disk formed after the optical disk is formed can be made closer to the ideal one than before. More specifically, the width or the length of the signal projection forming protrusion of the resist is set to the width or the length of the signal pit of the optical disc by the dry etching of the resist and the stamper substrate. By increasing the value at least by a value inversely proportional to the selection ratio, the accuracy of the shape of the signal pit by etching can be further increased.

The inclination angle of the side wall of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is equal to or more steep than the inclination angle of the side wall of the signal pit of the optical disk. By adjusting the angle to an appropriate angle, the retreat (reduction) of the convex end of the resist mask during etching and the transfer failure during optical disk molding are alleviated, and the pit shape of the optical disk finally formed after optical disk molding is ideal. Can be brought closer than before.
More specifically, with respect to the inclination angle of the signal pit sidewalls of the optical disc, the inclination angle of the sidewalls of the signal projection forming protrusions of the resist is determined by the selectivity of the resist and the stamper substrate during the dry etching. If the value is reduced by the inversely proportional value, the accuracy of the shape of the signal pit due to etching can be further increased.

As a specific method of changing the process conditions, the laser beam profile is changed, and the time width of the recording signal pulse of the recording laser beam is set to a value smaller than the time required for the signal pit length of the optical disk. If the recording laser beam is exposed so as to be at least longer by a value inversely proportional to the selectivity at the time of the dry etching of the stamper substrate, it is possible to change the length or width or the inclination angle of the signal projection forming protrusion. .

Therefore, the signal projections of the stamper and the pits of the molded optical disk according to the present invention can realize an optimal shape.

The parameters that are finely adjusted on a daily basis include the laser beam intensity, the diameter of the incident beam to the recording lens, and the duty of the recording signal. It is desirable to constantly monitor and manage the laser beam profile.

In the production of optical disks, development,
It is conceivable that the process conditions of the post-process such as etching and molding slightly move, and the signal pits of the optical disk gradually change. However, according to the method of the present invention,
Since each of the above parameters can be finely adjusted, it is easy to return the signal pits of the optical disk to the optimum values. Further, if each parameter is managed, it is possible to accurately grasp where the subsequent process has changed, so that the process can be reliably managed.

As described above, the stamper according to the present invention,
The mastering method and the optical disc realize a shape that optimizes a reproduction signal and have good quality. Further, the yield can be improved because the process can be easily controlled.

[Brief description of the drawings]

FIG. 1 (A), (B), (C), (D), (E),
(F) is a process drawing showing the direct dry mastering method of the optical disk stamper according to the first embodiment of the present invention.

FIG. 2 (A), (B), (C), (D), (E),
(F) is a process drawing showing the direct dry mastering method of the optical disk stamper according to the second embodiment of the present invention.

FIG. 3 (A), (B), (C), (D), (E),
(F) is a process drawing showing the direct dry mastering method of the stamper for an optical disc according to the third embodiment of the present invention.

FIG. 4 is a schematic view of an etching apparatus of a direct dry mastering apparatus for a stamper for an optical disc according to a fourth embodiment of the present invention.

FIG. 5 (A), (B), (C), (D), (E),
(F), (G) is a process diagram showing the fabrication of a stamper according to the conventional example.

FIGS. 6A, 6B, and 6C are a plan view, a cross-sectional view, and a right side view schematically showing the shape of a pit of an optical disc, respectively.

FIGS. 7A and 7B are cross-sectional views for explaining the dimensional relationship in the track direction of the optical disk between the signal protrusion forming protrusions of the resist and the signal protrusions of the stamper substrate.

FIGS. 8A and 8B are cross-sectional views illustrating the dimensional relationship in the longitudinal direction between a signal projection forming protrusion of a resist and a signal projection of a stamper substrate.

FIGS. 9A and 9B are diagrams showing the relationship between the laser beam exposure intensity and the position of the signal projection forming protrusion of the resist in the track direction in the fifth embodiment of the present invention;
FIG. 9 is an explanatory diagram for describing the relationship diagram and a change in a dimension of a signal projection forming protrusion of a resist in a track direction cross section.

10 (A), (B), (C), and (D) show recording signals when changing a longitudinal cross-sectional dimension of a signal projection forming protrusion of a resist in a fifth embodiment of the present invention. FIG. 7A is a diagram showing the relationship between ON / OFF and time, FIG. 7A is a diagram showing the relationship between the exposure power of the laser beam corresponding to the signal pulse, and time, and FIG. FIG. 3 is a plan view of a projection for forming a signal projection formed after development as a result of the exposure.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 stamper substrate 2 negative resist layer for dry development 3 recording laser beam 4 recording lens 5
... Protrusions for forming signal protrusions of resist remaining after dry development, 5A. Protrusions for forming signal protrusions of resist remaining after etching, 6... Signal protrusions formed on stamper substrate,
7: part exposed by laser beam, 8: range heated by laser beam, 11: stamper substrate processed to stamper size, 12: negative type resist layer for dry development, 15: resist remaining after dry development Signal protrusion forming protrusions, 15A ... Signal protrusion forming protrusions of resist remaining after etching, 16 ... Signal protrusions formed on stamper substrate, 21 ... Stamper substrate, 21a ... Base layer of stamper substrate (stamper substrate main body) , 21b
... Dry etching layer of stamper substrate, 22 ... Negative type resist layer for dry development, 25 ... Protrusion for forming signal protrusion of resist remaining after dry development, 25A ... Protrusion for forming signal protrusion of resist remaining after etching, 26 …
Signal protrusions formed on the stamper substrate, 31: stamper substrate, 32: positive type resist layer, 33: developer supply nozzle, 34: pits formed by development, 35: conductive film, 36: nickel thick film, 40 etching chamber, 41 upper electrode, 42 lower electrode, 43 stamper substrate, 44 matching device, 45 high frequency power supply, 46
... Exhaust pump, 47 ... Reaction gas supply pipe, 48 ... Valve, 49 ... Pipe from tank, 50 ... Pipe from tank, 51 ... Pipe from tank, 52 ... Optical fiber for end point detection and monitoring, 53 ... End point detection device , 54 ... Control device,
Reference numerals 100: optical system, 101: rotary drive device, 160: pit, 210: beam profile, 211: beam profile with reduced intensity, 212: beam profile with reduced lens numerical aperture, 213: signal pulse.

Claims (30)

[Claims] An exposure section and an unexposed section are exposed by exposing a laser beam, which is signal-modulated and narrowed down by a recording lens, onto a surface of a substrate on which a resist layer of a negative type photoresist is formed by rotating the substrate. After that, heat treatment, development by dry process, etching by dry process, and resist removal by dry process are successively performed to form signal protrusions on the surface of the substrate, and then to a mold of an optical disk molding machine. A direct dry mastering method for an optical disk stamper, comprising manufacturing the optical disk stamper by processing the substrate to an appropriate stamper size. 2. A substrate, on which a resist layer of a negative type resist is formed and processed into a stamper size suitable for a mold of an optical disk molding machine, is rotated, and the signal is modulated on the surface of the rotating substrate. Exposure to a laser beam to form an exposed portion and an unexposed portion, followed by heat treatment, development by a dry process,
A direct dry mastering method for a stamper for an optical disc, wherein a stamper for an optical disc is manufactured by performing etching by a dry process and removing resist by a dry process. 3. The direct dry mastering method for an optical disk stamper according to claim 1, wherein the heat treatment after the exposure is performed in an organic Si gas atmosphere such as hexamethyldisilazane. 4. The direct dry mastering method for an optical disk stamper according to claim 1, wherein the steps of developing, etching, and removing the resist are performed in the same chamber by changing only the reaction gas. 5. The stamper substrate having the negative type resist layer on its surface, the stamper substrate comprising at least one of nickel, chromium, aluminum, titanium, cobalt, iron, molybdenum, tungsten, boron, copper, and tantalum as a main component. 5. The direct dry mastering method for an optical disc stamper according to claim 1, wherein the stamper is formed of a material to be formed. 6. The stamper substrate having the negative type resist layer on its surface is made of Si, SiO ₂ , or Si.
5. The direct dry mastering method for an optical disk stamper according to claim 1, wherein the stamper is formed from a silicon compound such as C. 7. The direct dry mastering method for an optical disk stamper according to claim 1, wherein the stamper substrate having the negative type resist layer on its surface is formed of glass. 8. The direct dry mastering of an optical disk stamper according to claim 1, wherein the stamper substrate having the negative type resist layer on its surface is formed of a material containing carbon as a main component. Method. 9. The dry etching layer of the stamper substrate having the negative type resist layer on a surface thereof,
The optical disc stamper according to any one of claims 1 to 8, wherein the stamper is formed from titanium nitride, titanium oxide, tantalum, tungsten, chromium, molybdenum, cobalt, boron, nickel phosphorus, nickel boron, or nickel cobalt. Direct dry mastering method. 10. The stamper substrate comprises: a base layer;
The dry etching layer has a two-layer structure in which the signal projection is formed by being partially removed by dry etching and disposed on the base layer, wherein the thickness of the dry etching layer is equal to the etching depth in the etching. Item 10. A direct dry mastering method for an optical disk stamper according to Item 9. 11. A rotating device for rotating a stamper substrate having a resist layer of a negative type photoresist on a surface thereof, and exposing a surface of the rotating stamper substrate with a laser beam modulated by a signal and focused by a recording lens. Exposure device for forming a part and an unexposed part, and thereafter, heat treatment, development by a dry process, etching by a dry process, and resist removal by a dry process are continuously performed to form signal protrusions on the surface of the stamper substrate. Direct-dry mastering of an optical disk stamper, comprising: a processing device that processes the stamper substrate into a stamper size suitable for a mold of an optical disk molding machine to produce a stamper for an optical disk. apparatus. 12. A rotating device for rotating a stamper substrate having a resist layer of a negative type resist on its surface and processed into a stamper size suitable for a mold of an optical disk molding machine, and a signal on the surface of the rotating stamper substrate. An exposure device that forms an exposed portion and an unexposed portion by exposing a laser beam that has been modulated and focused by a recording lens, and then, after a heat treatment, development by a dry process;
A direct dry mastering device for a stamper for an optical disc, comprising: a processing device for producing a stamper of an optical disc by performing etching by a dry process and removing resist by a dry process. 13. The direct dry mastering of an optical disk stamper according to claim 11, wherein the processing device performs the heat treatment after the exposure in an organic Si gas atmosphere such as hexamethyldisilazane. apparatus. 14. The processing apparatus according to claim 1, wherein the processing, development, etching,
13. The direct dry mastering apparatus for an optical disk stamper according to claim 11, wherein the step of removing the resist is performed in the same chamber by changing only the reaction gas. 15. The stamper substrate having the negative type resist layer on its surface, the stamper substrate comprising at least one of nickel, chromium, aluminum, titanium, cobalt, iron, molybdenum, tungsten, boron, copper, and tantalum as a main component. The direct dry mastering apparatus for an optical disk stamper according to any one of claims 11 to 14, wherein the apparatus is formed of a material to be formed. 16. The stamper substrate having the negative type resist layer on its surface is made of Si, SiO ₂ , S
11. A film made of a silicon compound such as iC.
15. The direct dry mastering device for a stamper for an optical disc according to any one of 14. 17. The direct dry mastering apparatus for an optical disk stamper according to claim 11, wherein the stamper substrate having the negative type resist layer on its surface is formed of glass. 18. The direct dry mastering of an optical disk stamper according to claim 11, wherein the stamper substrate having the negative type resist layer on its surface is formed of a material containing carbon as a main component. apparatus. 19. The stamper substrate having the negative type resist layer on its surface, a base layer and a dry etching layer disposed on the base layer and partially removed by dry etching to form the signal projections. 19. The dry etching layer having a two-layer structure, wherein the dry etching layer is formed of titanium nitride, titanium oxide, tantalum, tungsten, chromium, molybdenum, cobalt, boron, nickel phosphorus, nickel boron, or nickel cobalt. A direct dry mastering apparatus for an optical disk stamper according to any one of the above. 20. The stamper substrate, comprising: a base layer;
The dry etching layer has a two-layer structure in which the signal projection is formed by being partially removed by dry etching and disposed on the base layer, wherein the thickness of the dry etching layer is equal to the etching depth in the etching. Item 20. A direct dry mastering device for an optical disk stamper according to item 19. 21. The width or length of a signal projection forming protrusion of a resist formed on the stamper substrate after the development is made larger than the width or length of a signal pit of the optical disk. The direct dry mastering method for an optical disk stamper according to claim 1. 22. The width or length of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is made larger than the width or length of the signal pit of the optical disk. 20. The direct dry mastering apparatus for an optical disk stamper according to claim 1, wherein 23. A rotating stamper substrate having a resist layer on its surface is exposed to a signal-modulated laser beam, the resist layer on the stamper substrate is subjected to a heat treatment, and then exposed to light on the resist layer by development. The unexposed portions are removed to form signal protrusion forming protrusions on the resist layer, and the stamper substrate is subjected to dry etching using the resist layer on which the signal protrusion forming protrusions are formed as a signal protrusion forming mask. In the stamper of direct mastering in which the signal projection is formed and the stamper substrate itself on which the signal projection is formed is used as a stamper for molding an optical disc, the width or the length of the signal pit of the optical disc is larger than the dimension of the signal pit after the development. Dimensions of the width or length of the signal projection forming protrusions of the resist formed on the stamper substrate Direct Dry mastering process of a stamper for an optical disc which is adapted to be increased. 24. The inclination angle of the side wall of the signal projection forming protrusion of the resist formed on the stamper substrate after the development is equal to or more steep than the inclination angle of the side wall of the signal pit of the optical disk. 24. The direct dry mastering method for an optical disk stamper according to claim 21 or 23, wherein the angle is set to a suitable angle. 25. A width or a length of a signal projection forming protrusion of the resist is set to a width or a length of a signal pit of the optical disk by the dry etching of the resist and the stamper substrate. 23. The method according to claim 21, wherein the value is at least increased by a value inversely proportional to the selection ratio.
5. The direct dry mastering method for an optical disk stamper according to 4. 26. The inclination angle of the side wall of the signal projection forming protrusion of the resist is opposite to the inclination angle of the side wall of the signal pit of the optical disk to the selectivity of the resist and the stamper substrate during the dry etching. 26. The direct dry mastering method for an optical disk stamper according to any one of claims 21 and 23 to 25, wherein the method is at least reduced by a proportional value. 27. The time width of the recording signal pulse of the laser beam is at least longer than the time required for the signal pit length of the optical disk by a value inversely proportional to the selectivity of the resist and the stamper substrate during the dry etching. The direct dry mastering method for an optical disk stamper according to any one of claims 21 and 23 to 26, wherein the exposure is performed after the exposure. 28. An optical disk stamper produced by the direct dry mastering method for an optical disk stamper according to any one of claims 21 and 23 to 27. 29. A signal-modulated laser beam is exposed to a rotating stamper substrate having a resist layer on its surface, the resist layer on the stamper substrate is heated, and then the resist layer is exposed by development. The portion or the unexposed portion is removed to form a projection for forming a signal projection on the resist layer, and the stamper is dry-etched using the resist layer on which the projection for forming a signal projection is formed as a mask for forming a signal projection. In a stamper for direct dry mastering for an optical disc, wherein a signal projection is formed on a substrate and the stamper substrate itself on which the signal projection is formed is used as a stamper for molding an optical disc, a width or a length of a signal pit of the optical disc is measured. Rather than for forming signal protrusions of a resist formed on the stamper substrate after the development. Width or length of the stamper large size disc for direct dry mastering parts. 30. An optical disk manufactured by using the direct dry mastering stamper according to claim 28.