JP2001216690A - Direct mastering method and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct mastering method which is capable of making a stamper with a small number of stages by directly etching substrates of metals, ceramics, etc., without subjecting the substrates to stages of electroforming etc., and is capable of improving quality and productivity and a device for the same. SOLUTION: The substrate is etched with the positive type resist as mask by a heat treatment, full-surface exposure and development processing while the resist on recorded and exposed parts is made to remain after signal recording of the resist on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a direct mastering method and apparatus for producing a stamper by etching.

[0002]

2. Description of the Related Art A process for producing a master of an optical disc is called a "mastering" process, and in this process, a master called a "stamper" is finally produced. The stamper is used as a mold in a later molding step, and the mold produces a large number of disk replicas.

Conventionally, pits formed in a photoresist on a glass master have been transferred to a nickel metal plate by electroforming to form a stamper. Therefore, the number of steps is large, and the quality and yield are reduced due to defects generated during the steps. In addition, there are disadvantages such as high equipment costs and manufacturing material costs.

FIG. 3 shows a conventional process for forming a stamper by etching a substrate.

FIG. 3A shows a stamper substrate 11 on which a negative resist is applied to form a negative resist film 12. Conventional rubber-based negative resists have poor resolution and are unsuitable for recording an original master of an optical disk. However, a chemically amplified negative type resist has recently been developed, and a high resolution type resist capable of forming a signal protrusion having a width of about 0.3 to 0.4 μm for an optical disk has become available.

Next, a signal is recorded on the negative resist film 12 formed by coating with a laser beam recorder. Although not shown here, a laser beam recorder as an example of an exposure apparatus, an optical system 7 for modulating a laser beam with a desired signal and exposing the laser beam along a radial direction of the stamper substrate 11, And a rotation drive device 8 for rotating at a rotation speed of. FIG. 3B shows a signal-modulated laser beam 3 and a recording lens 4 which squeezes the laser beam 3 to a submicron size and exposes the resist film 12 on a rotating stamper substrate 11. next,
The stamper substrate 11 subjected to the signal exposure is heated in an oven or the like.

FIG. 3C shows a heat treatment called PEB (post-exposure bake) performed on a chemically amplified resist. In this step, the acid generated by the exposure acts as a catalyst to accelerate the crosslinking reaction of the resist film 12 in a chain reaction. That is, the exposed portion becomes insoluble in the developer.

FIG. 3D shows a developing step performed next. A developing solution is applied from the nozzle 9 onto the rotating stamper substrate 11 to perform development. After the development, the exposed portions of the resist film 12 are insoluble in the developing solution.
3,..., 13 remain. After rinsing with pure water and drying, dry etching is performed using the projections 13,..., 13 as a mask. As the etching, reactive ion etching, ion beam etching, or the like is performed.

FIG. 3E shows the stamper substrate 11 after the etching. The projections 13,..., 13 have become thinner after etching. Reference numeral 14 denotes a signal protrusion formed on the stamper substrate 11.

FIG. 3F shows that each projection 1 is formed by ashing.
3 shows a state after removing the residual resist on the top 3, and a so-called master is completed. Ashing is a process in which a resist is decomposed into CO ₂ and H ₂ O by oxygen radicals of oxygen plasma. Thereafter, if the inner and outer diameters of the master substrate are processed so as to be attached to the mold of the molding machine, the stamper is completed.

[0011]

However, in the above-mentioned conventional example, a chemically amplified negative type photoresist is used. However, in this resist, the acid generated by exposure acts as a catalyst to crosslink the exposed portion. A reaction is caused to change the resist into a structure insoluble in a developer. Therefore, if a basic substance such as ammonia is present in the surrounding environmental atmosphere, the generated acid is deactivated, which greatly affects the insolubility in development. Therefore, it is necessary to remove the surrounding ammonia component on the order of ppb, and to constantly control the value. Also, the waiting time from the exposure to the heat treatment called the PEB (post-exposure bake) has a great influence on the insolubility in the development, and it is necessary to pay attention to the time management between the steps. As described above, it is extremely difficult to use a chemically amplified resist stably, and a process using the resist requires cost for environmental maintenance and management, and production is not stable.

[0012] Accordingly, an object of the present invention is to solve the above-mentioned problems, and by directly etching a substrate such as metal or ceramic without passing through a process such as electroforming,
It is an object of the present invention to provide a direct mastering method and a device which can manufacture a stamper with a small number of steps and can improve quality and productivity.

[0013]

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

According to a first aspect of the present invention, a photoresist on a stamper substrate is selectively exposed by a signal-modulated laser, and after development, the substrate is etched by using the remaining resist as a mask. In a direct mastering method using a direct stamper, a positive resist is used as the photoresist, and after the selective exposure by the laser, the exposed portion of the resist is insoluble in a developing solution by a heat treatment. After the unexposed portion is removed, the substrate is etched using the resist remaining in a portion corresponding to the exposed portion of the resist as a mask to directly use the substrate as a stamper.

According to a second aspect of the present invention, the photoresist is a positive resist composed of orthodiazonaphthoquinone and a novolak resin. After the exposure by the signal-modulated laser, the resist is heated to A decarboxylation reaction is caused to the carboxylic acid generated in the exposed portion at the time of exposure, and the carboxylic acid is converted into a hydrocarbon insoluble in an alkali developing solution. The direct mastering method according to the aspect is provided.

According to a third aspect of the present invention, the heating after the exposure is performed in an atmosphere in which a basic substance is present, and the alkaline developing solution is used during development. Provide a direct mastering method.

According to a fourth aspect of the present invention, there is provided the direct mastering method according to the third aspect, wherein the basic substance is ammonia or an amine compound.

According to a fifth aspect of the present invention, there is provided the direct mastering method according to the first or second aspect, wherein the positive resist is a mixture of orthodiazonaphthoquinone and a novolak resin containing a basic substance. provide.

According to a sixth aspect of the present invention, an exposure apparatus for selectively exposing a positive photoresist on a stamper substrate with a signal-modulated laser, and a developing solution for exposing an exposed portion of the resist by heat treatment A developing device that develops the developing solution with the developing solution to leave only exposed portions and removes unexposed portions of the resist; and a light exposure device that is exposed to portions corresponding to the exposed portions of the resist. And an etching device for etching the substrate using the portion as a mask and using the substrate directly as a stamper.

According to a seventh aspect of the present invention, in the exposure apparatus, the laser selectively exposes the photoresist, which is a positive resist composed of orthodiazonaphthoquinone and a novolak resin, using the laser. After the exposure by the signal-modulated laser in the exposure apparatus, the resist is heated to cause a decarboxylation reaction on the carboxylic acid generated in the exposed portion at the time of the exposure, so that the carboxylic acid is insoluble in the alkali developer. On the other hand, the direct mastering device further comprises an ultraviolet exposure device for exposing the entire surface of the substrate with ultraviolet light after converting the carboxylic acid into a hydrocarbon insoluble in an alkali developing solution. The direct mask according to the sixth aspect, wherein the substrate after the ultraviolet exposure with an exposure device is developed using an alkali developing solution. To provide a Taringu apparatus.

According to an eighth aspect of the present invention, there is provided the sixth or seventh aspect, wherein the heating by the heating device is performed in an atmosphere in which a basic substance is present, and an alkaline developer is used during development. To provide a direct mastering device.

According to a ninth aspect of the present invention, there is provided the direct mastering apparatus according to the eighth aspect, wherein the basic substance present at the time of heating by the heating device is ammonia or an amine compound.

According to a tenth aspect of the present invention, in the exposure apparatus, the positive resist selectively exposed with the laser is a mixture of orthodiazonaphthoquinone and a novolak resin containing a basic substance. A direct mastering device according to a sixth or seventh aspect is provided.

[0024]

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

FIG. 1 shows a process of forming a stamper by etching a substrate in a direct mastering method according to an embodiment of the present invention.

As shown in FIG. 1, a photoresist film 2 on a stamper substrate 1 is selectively exposed by a signal-modulated laser, and after development, the substrate is etched by using the remaining resist as a mask. Is used as a direct stamper, a positive type resist used in the conventional method of forming a stamper by electroforming, that is, a positive type resist composed of orthodiazonaphthoquinone and a novolak resin is used as the photoresist. Then, after the selective exposure by the laser, the exposed portion of the resist is made insoluble in an alkali developing solution by a heat treatment, in other words, the exposed portion remains at the time of development. It is characterized in that it is inverted. Therefore, both the resolution and the good handling of the conventional positive resist can be realized, that is, the same management as the conventional resist is sufficient, and
The new direct mastering method achieves the same resolution as the conventional one.

An apparatus for implementing the direct mastering method according to one embodiment of the present invention includes:
An exposure device for selectively exposing the positive photoresist on the stamper substrate with a signal-modulated laser, a heating device for making the exposed portion of the resist insoluble in a developing solution by heat treatment, and An ultraviolet exposure apparatus for exposing with ultraviolet light, a developing apparatus for developing with the developing solution to leave only the exposed portions and remove the unexposed portions of the resist, and thereafter, to a portion corresponding to the exposed portions of the resist. And an etching apparatus for etching the substrate using the exposed portion as a mask and using the substrate directly as a stamper.

Hereinafter, the above embodiment will be described in detail with reference to FIG.

In FIG. 1A, reference numeral 1 denotes a stamper substrate, on which a positive type photoresist is applied to form a photoresist film 2. In one example, the resist is comprised of orthodiazonaphthoquinone and a novolak resin. In FIG. 1A, the stamper substrate 1 has already been dimensioned such as an inner diameter so that it can be mounted on a mold of a molding machine. This processing need not necessarily be performed in advance, and may be performed last. As the stamper substrate 1, a metal having physical properties such as a thermal conductivity and a thermal expansion coefficient close to those of a conventional nickel plate does not need to change the molding conditions, and therefore, the same as the conventional one can be used. . However, the stamper substrate 1 is not limited to metal, but may be ceramic, glass, a silicon compound, or the like. The material of the stamper substrate 1 is selected in consideration of the etching quality, heat resistance during molding, abrasion resistance, economy, and the like.

FIG. 1B shows a state where a signal is recorded by a laser beam recorder. The stamper substrate 1 is mounted on a turntable 8a and rotated by a rotation driving device 8, and a laser beam signal-modulated by a laser beam recorder (not shown) is exposed on the resist film 2. FIG. 1B shows an optical system 7 of the laser 3 and the recording lens 4. The recording lens 4 is for narrowing the laser beam 3 to a submicron size.

Next, FIG. 1C shows a state where the stamper substrate 1 is heated to cause a decarboxylation reaction.
This heat treatment is performed using an example of a heating device that constitutes a part of the direct mastering device according to the above embodiment that performs baking in an ammonia atmosphere, as shown in FIG.
In FIG. 2, reference numeral 16 denotes an infrared heater disposed in the chamber 15, reference numerals 17 and 17 'denote support members for supporting the stamper substrate 1 in the chamber 15, reference numeral 18 denotes a vacuum exhaust duct of the chamber 15, and reference numeral 19 denotes an inside of the chamber 15. For injecting ammonia into the pipe. In the exposed portion 5 of the resist film 2, aromatic carboxylic acid is generated by exposure, but CO ₂ is released from the exposed portion 5 by heating by the infrared heater 16 of the heating device and is insoluble in an alkali developing solution. Of the aromatic hydrocarbon remain in the exposed portion 5. This decarboxylation reaction is likely to occur when a basic substance is present. For this purpose, in the above-described embodiment, the stamper substrate 1 is put into the vacuum chamber 15 of the above-described heating apparatus in FIG. After that, a basic substance such as ammonia or an amine-based compound is injected into the vacuum chamber 15 from the pipe 19, and the heating and baking of the stamper substrate 1 is performed in an atmosphere where the basic substance exists in the vacuum chamber 15. By the heating device, the support member 17,
The stamper substrate 1 supported by 17 ′ is heated by the infrared heater 16 to, for example, about 90 to 100 ° C.

Thereafter, the stamper substrate 1 is taken out of the chamber 15 and placed in a place without a basic atmosphere.
As shown in (d), the entire surface of the resist film 2 is exposed with ultraviolet light UV from an ultraviolet light exposure device. At this time, alkali-soluble indene carboxylic acid is generated in the unexposed portion of the resist film 2 that has not been exposed in FIG.

Next, as shown in FIG. 1 (e), a developing solution is supplied from a developing solution supply nozzle 9 of the developing device to perform development. At this time, the stamper substrate 1 is rotated by a rotation drive system (not shown). As an example of a rotary drive system,
As used in FIG. 1B, the stamper substrate 1 can be mounted on the turntable 8a and rotated by the rotation drive device 8. As described above, in the resist film 2,
Since the exposed portion 5 on which the signal is recorded is alkali-insoluble and the unexposed portion is alkali-soluble, after development, the exposed portion 5 is left as protrusions 5a,..., 5a as shown in FIG. It is. Using the residual resist protrusions 5a,..., 5a as a mask, etching is performed by an etching apparatus. Reactive ion etching is generally used for etching. However, depending on the type of the stamper substrate 1, an optimal method such as ion beam etching or sputter etching is used.

FIG. 1F shows the stamper substrate 1 after the etching. Residual resist protrusions 5 on stamper substrate 1
Signal projections 6,..., 6 are formed under a,.

Next, as shown in FIG. 1 (g), the remaining resist protrusions 5a,..., 5a are removed by ashing to leave only the signal protrusions 6,. The stamper substrate 1 in this state is completed as a stamper, and the completed stamper can be mounted on a molding machine to mold an optical disk.

According to the above embodiment, after the resist film 2 is exposed by the signal-modulated laser, the resist film 2 is exposed.
Is heated to cause a decarboxylation reaction of the carboxylic acid generated in the exposed portion 5 to change it into a hydrocarbon insoluble in the developing solution. Then, a so-called flood exposure in which the entire resist film is exposed to ultraviolet light is performed, and the signal is modulated. The unexposed portion of the laser is converted into a carboxylic acid soluble in alkali, and then developed and removed with an alkali developing solution. As a result, only the resist film 5a of the exposed portion 5 at the portion exposed by the signal-modulated laser remains. When the stamper substrate 1 is etched using the remaining resist film 5a of the exposed portion 5 as a mask, the exposed portion 5
Are formed as protrusions 6,..., 6, and can be used as stampers. In this way, both the resolution and the good handling of the conventional positive resist can be realized, that is, the resist can be managed in the same manner as the conventional positive resist made of novolak resin, and
The present invention realizes a new direct mastering method capable of obtaining a resolution of 0.2 to 0.3 μm, which is the same as the conventional resolution. In other words, without going through processes such as electroforming,
By etching a substrate such as metal or ceramic, a stamper can be manufactured with a small number of processes.
Quality and productivity can be improved.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

For example, as another embodiment of the present invention, the positive resist shown in FIG. 1 can be used which contains a basic substance in its components. This is Figure 1
This is because the decarboxylation reaction is likely to occur when a basic substance is present, for the same reason as in the case of heating in an atmosphere of a basic substance in (c). In this case, the other steps are the same as those of the above-described embodiment, but there is an advantage that the heat baking treatment in FIG. 1C does not need to be performed in a basic substance.

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.

[0040]

According to the direct mastering method and apparatus of the present invention, after exposing a resist by a signal-modulated laser, the resist is heated to make the exposed portion of the resist insoluble in a developing solution, thereby developing the resist. Sometimes, after removing the unexposed portions of the resist, the substrate is etched directly using the resist remaining in the portions corresponding to the exposed portions of the resist as a mask, and the substrate is directly used as a stamper. The substrate is made and can be used as a stamper. In this way, a high-quality stamper can be made by a simple method without using electroforming, etc., and it is difficult to handle like a chemically amplified negative resist, and the surrounding environmental atmosphere is strictly controlled. No need.

Further, according to the present invention, since the positive resist used in the conventional mastering method can be used, the process conditions which have been established and proven, such as the application condition to the substrate and the recording power condition at the time of laser recording, can be used. Can be used, and stable production can be achieved.

The photoresist is a positive resist composed of orthodiazonaphthoquinone and a novolak resin, and after exposure with the signal-modulated laser,
The above-mentioned resist is heated to cause a decarboxylation reaction of the carboxylic acid generated in the exposed portion at the time of the above-mentioned exposure, thereby converting the above-mentioned carboxylic acid into a hydrocarbon which is insoluble in an alkali developing solution. In this case, a resist and a developing solution which are conventionally used can be used.

If heating after exposure is performed in an atmosphere in which a basic substance is present, a decarboxylation reaction can be easily caused due to the presence of the basic substance, which corresponds to the exposed portion of the resist. Can be made smoothly insoluble in an alkali developing solution.

If a positive resist containing a mixture of orthodiazonaphthoquinone and novolak resin containing a basic substance is used, a decarboxylation reaction can be easily caused, and the heat treatment can be carried out with a basic substance. The advantage is that it does not have to be performed in the substance.

[Brief description of the drawings]

FIG. 1 (a), (b), (c), (d), (e),
(F) is an explanatory view showing a step of forming a stamper by etching the substrate in the direct mastering method according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a heating device for direct mastering according to the embodiment of the present invention.

FIG. 3 (a), (b), (c), (d), (e),
(F) is an explanatory view showing a conventional process of forming a stamper by etching a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stamper board, 2 ... Positive resist, 3 ... Laser beam, 4 ... Recording lens, 5 ... Exposure part, 5a ... Residual resist protrusion, 6 ... Signal protrusion, 7 ... Optical system, 8 ... Rotation drive device, 9 ... Developing solution nozzle, 11: conventional stamper substrate, 12: conventional chemically amplified negative resist, 13: residual resist in the exposed part, 14: signal protrusions formed on the stamper substrate, 15: vacuum chamber of heating device Reference numeral 16: an infrared heater; 17, 17 ': a substrate support member; 18, a vacuum exhaust duct; 19, an ammonia injection duct.

Claims (10)

[Claims] A photoresist on a stamper substrate is
With a signal-modulated laser, selectively exposed and developed, after development, in a direct mastering method in which the substrate is etched using the residual resist as a mask and the substrate is directly stamped, using a positive resist as the photoresist, After the selective exposure by the laser, the exposed portion of the resist is insoluble in a developing solution by a heat treatment, and after the unexposed portion of the resist is removed during development, it remains in a portion corresponding to the exposed portion of the resist. A direct mastering method, wherein the substrate is directly used as a stamper by etching the substrate using a resist as a mask. 2. The method according to claim 1, wherein the photoresist is a positive resist composed of orthodiazonaphthoquinone and a novolak resin. After exposure by the signal-modulated laser, the photoresist is heated to form a photoresist on an exposed portion during the exposure. The direct mastering method according to claim 1, wherein a decarboxylation reaction is caused in the acid to convert the carboxylic acid into a hydrocarbon insoluble in an alkali developing solution, and thereafter, the entire surface is exposed to ultraviolet light and then developed with an alkali developing solution. 3. The direct mastering method according to claim 1, wherein the heating after the exposure is performed in an atmosphere in which a basic substance is present, and an alkali developing solution is used during development. 4. The direct mastering method according to claim 3, wherein the basic substance is ammonia or an amine compound. 5. The direct mastering method according to claim 1, wherein the positive resist is a mixture of orthodiazonaphthoquinone and a novolak resin containing a basic substance. 6. An exposure apparatus for selectively exposing a positive photoresist on a stamper substrate with a signal-modulated laser, and a heating apparatus for making an exposed portion of the resist insoluble in a developing solution by heat treatment. And a developing device that develops with the developer to leave only the exposed portions and remove the unexposed portions of the resist, and etches the substrate using the exposed portions remaining as masks in portions corresponding to the exposed portions of the resist. A direct mastering apparatus comprising: an etching apparatus that directly uses the substrate as a stamper. 7. The exposure apparatus, wherein the laser includes:
The photoresist, which is a positive resist composed of orthodiazonaphthoquinone and a novolak resin, is selectively exposed, and the heating device heats the resist after exposure by the signal-modulated laser in the exposure device. While the decarboxylation reaction occurs in the carboxylic acid generated in the exposed part during the exposure to change the carboxylic acid into a hydrocarbon insoluble in the alkali developing solution, the direct mastering device converts the carboxylic acid insoluble in the alkali developing solution. 7. An ultraviolet exposure device for exposing the entire surface of the substrate to ultraviolet light after converting the hydrocarbon to hydrocarbons, wherein the developing device develops the substrate exposed to ultraviolet light by the ultraviolet exposure device using an alkali developing solution.
A direct mastering device according to item 1. 8. The direct mastering device according to claim 6, wherein the heating by the heating device is performed in an atmosphere in which a basic substance is present, and an alkaline developer is used at the time of development. 9. The direct mastering device according to claim 8, wherein the basic substance present at the time of heating by the heating device is ammonia or an amine compound. 10. The positive resist according to claim 6, wherein the positive resist selectively exposed by the laser is a mixture of orthodiazonaphthoquinone and a novolak resin containing a basic substance. Direct mastering device.