JP2776453B2 - Photoresist developing apparatus and developing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing apparatus and a developing method for a photoresist, and more particularly to a developing apparatus and a developing method for a photoresist in manufacturing a master of an optical disk for audio, video or information. It is.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the accompanying drawings. First, an outline of a method for manufacturing an optical disk will be described. FIG. 2 is a first manufacturing process diagram for explaining an embodiment of the developing device and the developing method of the present invention, and an optical disk manufactured by the conventional developing device. FIG.
FIG. 7 is a second manufacturing process diagram for explaining an embodiment of the developing device and the developing method of the present invention, and an optical disc manufactured by the conventional developing device. 2 and 3,
Reference numeral 20 denotes a glass substrate, 21 denotes a photoresist, 22 denotes laser light, 23 denotes a condenser lens, 24 denotes an exposure unit,
25 is nickel, 26 is polycarbonate resin, 2
Reference numeral 7 denotes a reflective film and a protective film, respectively.

[0003] First, a photoresist 21 is uniformly applied to the surface of a precisely polished disk-shaped glass substrate 20 by a spin coating method via an adhesive, and then coated by a hot plate or the like. -King (FIG. 2 (A)).
Next, a laser beam 22 modulated by a signal to be recorded is condensed by a lens 23 and is irradiated onto a photoresist 21 to expose a predetermined portion (FIG. 2).
(B)). The pattern of the exposure unit 24 is a group of pits in the case of a read-only optical disk (CD, LD, CD-ROM, etc.), and is a recordable / reproducible optical disk (a magneto-optical disk, a phase-change optical disk, a CD writer). Once) is a group of groups. Next, the photoresist 21 is developed using an alkaline solution to dissolve the exposed portion 24, thereby obtaining an uneven pattern of the photoresist 21 composed of pits or groups (FIG. 2C). .

Next, a conductive film such as nickel is formed on the photoresist 21 by a sputtering method or the like.
Further, using this conductive film as an electrode, nickel 25 is plated to a predetermined thickness (FIG. 2D). As a result, the reverse pattern of the concavo-convex pattern of the photoresist 21 becomes nickel 2
5 is copied. Next, the nickel 25 is peeled off from the glass substrate 20 to form a stamper (FIG. 3).
(A)). Next, using this stamper as a mold for injection molding, the polycarbonate resin 26 and the like are injection molded (FIG. 3B). A predetermined pattern is formed on the polycarbonate resin 26. Finally, a reflective film and a protective film 27 are formed by sputtering or the like on the surface of the polycarbonate resin 26 from which the pattern has been removed, and the optical disk is completed (FIG. 3). (C)).

By the way, in the case of optical disks, in recent years,
Higher recording densities are being promoted not only in recordable and reproducible information optical discs but also in read-only optical discs. Means for achieving this higher recording density include narrowing the track pitch and increasing the linear recording density. That is, it is necessary to reduce the size of the pit or groove on which information is recorded. However, if an optical disk is manufactured by a conventional manufacturing method and the size of a pit or a groove is reduced, minute distortions and variations in these physical dimensions, which cannot be avoided in the manufacturing process, have a relatively large effect. As a result, the performance of the optical disc is deteriorated, the production yield is reduced, and the productivity is reduced.

[0006] Minute distortion or variation in the physical dimensions of pits or grooves can occur in all the processes related to the formation of pits or grooves in the optical disk manufacturing process. The influence of minute distortion and variation in physical dimensions generated when forming the pattern of the group is the greatest. The slight distortion or variation in physical dimensions generated here affects all subsequent processes.

Therefore, a developing method for forming a pit or groove pattern in a photoresist will be described. FIG. 4 is a schematic configuration diagram showing a conventional developing device. 4, reference numeral 30 denotes a developing device, 31 denotes a developer, 32 denotes a developer supply unit, 33 denotes a glass substrate, and 3 denotes a glass substrate.
4 is a He-Ne laser, 35 is a laser beam, 35a
Represents the + 1st-order diffracted light, 35b represents the 0th-order diffracted light, and 35c represents −
1st order diffracted light, 36 is a mirror, 37a is a photodetector,
37b is a photodetector, 37c is a photodetector, 38 is a tar detector.
Table 39 indicates a motor, and 40 indicates a development monitor.

First, an outline of the configuration of a conventional developing device will be described. There is a turntable 38 for setting a glass substrate 33 on which a photoresist has been applied and the photoresist has been partially exposed to predetermined portions by laser light. The turntable 38 is connected to a motor 39 so that it can rotate in a predetermined manner. Above the glass substrate 33, a developer supply section 32 for supplying the developer 31 and a rinsing liquid supply section (not shown) are arranged.

On the other hand, in order to monitor the progress of the development of the photoresist, a development monitor utilizing the diffraction phenomenon is used.
40 are arranged. This development monitor 40 is a laser
A He-Ne laser 34 is used as the light source.
The laser light 35 changes its optical path by a mirror 36 and is incident from the glass surface of the glass substrate 33. When passing through the photoresist, the laser light 35 undergoes diffraction and is separated into diffracted light.
Among them, the + 1st-order diffracted light 35a and the 0th-order diffracted light 35b
And the -1st-order diffracted light 35c are
The respective intensities can be measured by a, 37b and 37c.

Next, the outline of the developing method will be described. First,
Glass substrate 3 on which exposed photoresist is formed
3 is set on the turntable 38. In the turntable 38, a sensor for detecting a glass substrate is arranged. After confirming that the glass substrate 33 has been set, the development sequence is executed. That is, the turntable 33 is rotated at 100 rpm, and the rinsing liquid is first sprayed from the rinsing supply section onto the glass substrate 33 for 30 seconds, and then the developer 31 is sprayed from the developer supply section 32. . Although the development proceeds with time, the development state is monitored by the development monitor 40. Photodetectors 37a, 3
When the intensity ratio of the + 1st-order diffracted light 35a, the 0th-order diffracted light 35b, and the -1st-order diffracted light 35c incident on 7b and 37c reaches a predetermined value, the supply of the developer 31 is stopped, and the rinsing liquid is supplied. Spray for 30 seconds.

When the series of the development sequence is completed, a drying sequence is started. The rotation speed of the turntable 38 is increased to 1500 rpm, and the rinsing liquid on the photoresist is shaken off by the centrifugal force generated by the high-speed rotation, and at the same time, the photoresist is dried by a high-speed atmosphere gas flow. When the drying is completed, the turntable 38 is stopped, and the glass substrate 33 is removed. Thus, the development processing is completed.

[0012]

The development of a photoresist using a developing device having a development monitor utilizing the above-mentioned diffraction phenomenon is performed by using a pit or groove on an optical disk having a relatively low recording density. However, it is not sufficient for pits or grooves of a high recording density optical disc. The diameter of the laser light spot obtained from the He-Ne laser needs to be several mm in order to secure the measurement sensitivity, and this size is the size of the measurement target area. The size of one pit to be measured is μ
m, so that a single measurement covers many pits simultaneously. In addition, since the development is performed while rotating the glass substrate, a very large number of pits are monitored.

The pit length ranges from 3T to 11T in the case of a CD, for example, according to the signal to be recorded, where T is the reference time length. However,
The optimum value of the intensity ratio between the 0th-order diffracted light and the 1st-order diffracted light differs depending on the length of the pit to be measured. Further, the intensity ratio between the 0th-order diffracted light and the 1st-order diffracted light changes depending on the width, length, depth and side shape of the pit, and the track pitch. Therefore, in the development monitoring method utilizing the diffraction phenomenon, the average state of many and many types of pits is monitored, so that the development process of a high-density optical disk that requires precise management is performed. Not enough to use.

Accordingly, the present invention provides a photoresist developing apparatus and a developing method for an optical disk, in which the development of an exposure latent image, which depends on the storage time after the exposure of the photoresist, can be performed in a small period, and the development at the time of developing the photoresist. The object of the present invention is to provide a photoresist developing apparatus and a developing method for an optical disk capable of minimizing minute distortion and variation in physical dimensions of pits and grooves and thereby producing a high recording density optical disk having good jitter characteristics with high yield. And

According to a first aspect of the present invention, there is provided a photoresist developing apparatus for an optical disk which performs development subsequent to exposure of a photoresist formed on a glass substrate. And a storage that manages the storage time of the developed substrate to be stored in the developed substrate storage unit so as not to exceed 3 hours. A time management unit and a development processing unit for performing development processing on the undeveloped substrate, and performing the development process on the development-finished substrate without the storage time exceeding 3 hours, The purpose is achieved. Further, according to a second aspect of the present invention, there is provided a method for developing a photoresist for an optical disk, wherein the photoresist formed on a glass substrate is exposed to light and then developed. The above object is achieved by setting the time until the start to within 3 hours.

[0016]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the developing device of the present invention. In FIG. 1, 1 is a photoresist developing device, 2 is a developing unprocessed substrate storage unit, 3 is a development processing unit, 4 is a storage time management unit, 5 is a storage shelf, and 6 is a nitrogen gas introduction unit. , 7 is a nitrogen gas discharge section, 8 is a transport section, 9a is a partition window, 9b is a partition window, 9c is a partition window, 10 is a motor, 11 is a turntable, and 1 is a turntable.
Reference numeral 2a denotes an undeveloped substrate, 12b denotes a substrate, 13 denotes a developing solution, 14 denotes a developing solution supply section, 15 denotes a rinsing liquid supply section, 16 denotes a nitrogen gas introduction section, and 17 denotes a nitrogen gas discharge section. , 18 indicate a solution discharge portion, and 19 indicates a nitrogen gas.

First, the outline of the structure of the photoresist developing device 1 will be described. The photoresist developing device 1 is roughly divided into an undeveloped unprocessed substrate storage unit 2, a development processing unit 3, and a storage time management unit 4. The undeveloped unprocessed substrate storage unit 2 is a place where the exposed undeveloped unprocessed substrate 12a is stored in a physically and chemically stable state, and includes a partition plate for accommodating a plurality of undeveloped unprocessed substrates 12a. Storage shelf 5 from which the undeveloped unprocessed substrate 12a can be taken in and out as needed.

Further, the storage shelf 5 is connected to a storage time management unit 4 for managing the time from the exposure of the photoresist to the start of the development processing. All developed unprocessed substrates 12a
Storage time is controlled. The storage time management unit 4
It is activated at the time when storage of the undeveloped substrate 12a is started, displays the storage time, and continues to output a signal to the outside to start development until the predetermined storage time is reached. ing.

The undeveloped unprocessed substrate storage section 2 is provided with a partition window 9a for taking in the exposed undeveloped unprocessed substrate 12a from outside, and for sending out the undeveloped unprocessed substrate 12a to the development processing section 3. There is a partition window 9b. These partition windows 9a and 9b are opened only when the undeveloped substrate 12a passes, and are usually closed to shut off the undeveloped substrate storage unit 2 and the outside. Further, a transport unit 8 for transporting the undeveloped substrate 12a on the storage shelf 5 is provided. A nitrogen gas 19, which is an inert gas at a constant temperature and filtered through a 0.1 μm filter, is introduced from the nitrogen gas introduction unit 6 into the undeveloped substrate storage unit 2. The pressure from the nitrogen gas release unit 7
It is controlled to be constant by discharging the excess nitrogen gas 19.

On the other hand, the developing section 3 has a turntable 11 for setting the substrate 12b. Turn
The bull 11 is connected to the motor 10 so that it can rotate in a predetermined manner. In addition, the turntable 11
Is mounted with a sensor (not shown) for detecting the presence of the substrate 12b. Substrate 12
b, a developer supply unit 14 for supplying the developer 13 and a rinse liquid supply unit 1 for supplying the rinse liquid.
5 are arranged. There is a solution discharging section 18 for discharging the used developer 13 and the rinsing liquid. The inside of the development processing unit 3 is set to be in a predetermined nitrogen gas atmosphere.
Nitrogen gas inlet 16 connected to a 0.1 μm filter
And a nitrogen gas releasing section 17 are arranged. There is a partition window 9c for taking out the developed substrate 12b to the outside. The partition window 9c is opened only when the substrate 12b passes, and is usually closed to shut off the developing unit 3 from the outside.
When the development processing unit 3 receives a signal to start development from the storage time management unit 4 when the development processing is completed, the development processing unit 3 immediately starts the development processing. The target of development processing is
Among the plurality of unprocessed substrates 12a, the unprocessed substrates 12a having the longest storage time within a predetermined storage time.

Next, the results of a study on a developing method using the above-described photoresist developing apparatus will be described. Optical disks were manufactured by changing the developing method, and their characteristics were evaluated. First, a method for manufacturing an optical disk will be described. However,
Since it is basically the same as the above-described conventional optical disk manufacturing method except for the developing process, the description will be made with reference to FIGS. Since the reference numerals are the same, the description is omitted.

First, a photoresist 21 composed of a cresol novolak resin and a benzophenone ester is uniformly applied to the surface of a precisely polished disk-shaped glass substrate 20 by a spin coat method via an adhesive. Then, the film is baked by a hot plate to obtain a film thickness of 80.
A 0 Å photoresist 21 was obtained (FIG. 2).
(A)). Next, a krypton laser beam 22 having a wavelength of 413 nm modulated by a signal to be recorded.
Is condensed by a lens 23, and this is
A predetermined portion is exposed over a required time of one hour by irradiating upward (FIG. 2B). The signal to be recorded has a track pitch of 0.72 μm and a minimum pit length T of 0.4.
This is a group of pits of 3T to 11T when the pitch is 7 μm.

Next, the photoresist 21 is developed using an aqueous solution of potassium hydroxide as a developing solution, and the exposed portion 24 is dissolved to obtain an uneven pattern of the photoresist 21 composed of pit groups (FIG. 2C). ). As the developing conditions, conditions for optimizing the modulation degree, the tracking error signal, and the symmetry, which indicate the reproduction characteristics of the optical disk, are used. At this time, five kinds of samples were prepared with the storage time from immediately after the exposure by the laser to the start of development as a parameter. That is, sample No. 1 has a storage time of 0 hours and sample No. 2
Indicates a storage time of 2 hours, and sample number 3 indicates a storage time of 3 hours.
Sample time 4 is the storage time of 4 hours, and sample number 5 is the storage time of 8 hours. Among them, sample numbers 1 to 3 show examples of the present invention, and sample numbers 4 and 5 show comparative examples.

Next, a conductive film such as nickel is formed on the photoresist 21 by a sputtering method or the like.
Further, using this conductive film as an electrode, nickel 25 is plated to a predetermined thickness (FIG. 2D). As a result, the reverse pattern of the concavo-convex pattern of the photoresist 21 becomes nickel 2
5 is copied. Next, the nickel 25 is peeled off from the glass substrate 20 to form a stamper (FIG. 3).
(A)). Next, using this stamper as a mold for injection molding, the polycarbonate resin 26 and the like are injection molded (FIG. 3B). A predetermined pattern is formed on the polycarbonate resin 26. Finally, a reflective film and a protective film 27 are formed by a sputtering method or the like on the surface of the polycarbonate resin 26 on which the pattern is removed, which is removed from the stamper, to manufacture an optical disk (FIG. 3 (C)).

Next, a method for evaluating an optical disk will be described.
Each of the manufactured optical disks was reproduced using a laser pickup having a wavelength of 670 nm and a numerical aperture NA of 0.6, and the reproduced output was analyzed by a time interval analyzer. Jitter was determined from the distribution of signals corresponding to the pits. Table 1 shows the results for each sample.

[0026]

[Table 1]

In Table 1, the jitter is 3T or 7
10 ⁵ signals from the pits of T are counted, an occurrence frequency distribution with respect to time is obtained, and a value obtained by dividing the standard deviation of the time axis fluctuation of this distribution by T is shown. According to Table 1, the storage time from immediately after exposure to the start of development is
The more it increases, the more the jitter deteriorates. If the storage time is within 3 hours, the jitter does not exceed 15% even in the smallest 3T pit, but if the storage time is 4 hours or more, the jitter exceeds 15%. . If the jitter exceeds 15%, the margin for pit separation during reproduction of the optical disk is reduced, which is not practical. When the jitter exceeds 17%, the C1 error increases, and it may be difficult to continuously reproduce the optical disk.

The jitter is, at the current resolution level,
It is caused by minute distortion or variation in the physical dimensions of the pit, which is difficult to measure by the SEM for length measurement. According to the above results, the effect of the storage time is more significant for the 3T pit having a small size. Large 7
Greater than for the T pit. This is presumably because the minute distortion and variation in the physical dimensions of the pits are not due to the size of the pits but to the diffusion of the exposure latent image depending on the storage time after exposure. That is, by the laser exposure, in the exposed portion of the photoresist, the photosensitive agent is decomposed and the interaction with the base cresol novolak resin is cut, but this portion is considered to diffuse with time. . Since the amount of movement due to this diffusion is constant irrespective of the size of the pits, it is considered that the amount of change is relatively larger in short pits than in long pits, and therefore the jitter is significantly increased.

As described above, the photoresist developing apparatus for an optical disk according to the present invention according to the present invention is a photoresist developing apparatus for an optical disk which performs development after exposure of a photoresist formed on a glass substrate. An undeveloped substrate storage section controlled to a constant pressure for storing processed and unprocessed substrates, and a storage time of the unprocessed substrates stored in the undeveloped substrate storage section is 3 hours.
A storage time management unit that manages the processing time so as not to exceed a time, and a development processing unit that performs a development process on the undeveloped substrate, wherein the storage time does not exceed 3 hours. By performing the above-described development processing, development can be performed during a period in which the diffusion of the exposure latent image depending on the storage time after the photoresist exposure is small, and a small distortion of the physical dimensions of pits and groups generated during the development of the photoresist. Accordingly, it is possible to provide a photoresist developing apparatus for an optical disk capable of minimizing fluctuations and variations thereof and thereby manufacturing a high recording density optical disk having good jitter characteristics with good yield. Further, according to a second aspect of the present invention, there is provided a method for developing a photoresist for an optical disk, wherein the photoresist formed on a glass substrate is exposed to light and then developed. By setting the time to start to within 3 hours, development can be performed in a period in which the diffusion of the exposure latent image, which depends on the storage time after photoresist exposure, is small, and the physical dimensions of pits and groups generated during development of the photoresist To minimize the slight distortion and variation of
Accordingly, it is possible to provide a photoresist developing method for an optical disc capable of manufacturing a high recording density optical disc having good jitter characteristics with a high yield.

[0030]

As described above, the photoresist developing apparatus of the present invention according to the first aspect of the present invention is a photoresist developing apparatus, comprising: an undeveloped substrate storage section for storing exposed and undeveloped substrates; A storage time management unit that manages the storage time of the undeveloped substrate stored in the undeveloped substrate storage unit, and a development processing unit that performs a development process on the undeveloped substrate, wherein the storage time By performing the development process on the undeveloped substrate without exceeding a predetermined time, the development of the exposure latent image depending on the storage time after photoresist exposure can be performed in a small period of time, and during the development of the photoresist Photoresist development that minimizes the small distortions and variations in the physical dimensions of pits and grooves that occur, thereby enabling high-density optical disks to be manufactured with high yield. It is possible to provide a location. Also,
The method for developing a photoresist according to the present invention according to claim 2 comprises:
In the photoresist development method, by setting the time from the exposure of the photoresist to the start of development within a predetermined time, development can be performed in a period in which the diffusion of the exposure latent image depending on the storage time after the photoresist exposure is small. Also, it is possible to provide a photoresist developing method capable of minimizing minute distortion and variation in physical dimensions of pits and grooves generated during development of a photoresist, thereby enabling high-density optical disks to be manufactured with high yield.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a developing device of the present invention.

FIG. 2 is a first manufacturing process diagram for explaining an embodiment of a developing device and a developing method of the present invention, and an optical disc manufactured by a conventional developing device.

FIG. 3 is a second manufacturing process diagram for explaining an embodiment of the developing device and the developing method of the present invention and an optical disk manufactured by the conventional developing device.

FIG. 4 is a schematic configuration diagram showing a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoresist developing apparatus 2 Unprocessed substrate storage part 3 Development processing part 4 Storage time management part

Continuation of front page (56) References JP-A-3-274057 (JP, A) JP-A-3-110822 (JP, A) JP-A-60-117627 (JP, A) JP-A-3-246930 (JP) , A) JP-A-4-211264 (JP, A) JP-A-58-90636 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 7/26 501 G03F 7/30 502 H01L 21/027 H01L 21/30

Claims (2)

(57) [Claims] 1. An optical disk photoresist developing apparatus for performing development subsequent to exposure of a photoresist formed on a glass substrate, wherein the development processing is controlled to a constant pressure for storing the exposed and processed substrate. A processing substrate storage unit, a storage time management unit that manages a storage time of the undeveloped substrate stored in the development-processed substrate storage unit so as not to exceed 3 hours, And a development processing section for performing the development processing on the processed substrate without the storage time exceeding 3 hours. 2. A method for developing a photoresist for an optical disk, wherein development is carried out subsequent to exposure of a photoresist formed on a glass substrate, wherein the time from the exposure of the photoresist to the start of development is within 3 hours. A method for developing a photoresist for an optical disk.