JP2006192399A - Photoresist coating method, resist pattern forming method, and master information carrier manufacturing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for applying a photoresist which is used for forming a resist pattern on the surface of a substrate with high precision and to provide a method for forming the resist pattern by using the method for applying the photoresist and a method for manufacturing a master information carrier by which a pattern consisting of a ferromagnetic thin film and corresponding to an information signal can be formed on the master information carrier with high precision. <P>SOLUTION: This method for applying the photoresist, namely, for forming a thin film pattern of a preset shape on the surface of the substrate 11 comprises a step of forming a non-formation area 122, where the thin film pattern is not formed, continuously from the central part of the substrate 11 toward the outer peripheral part so that the thickness of a photoresist film 12 in a thin film pattern forming area 121 that the thin film pattern is formed is made thicker than that of the photoresist film in the non-formation area 122. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoresist coating method in which contact exposure is performed by evacuation, a resist pattern forming method, and a master information carrier manufacturing method used for transferring and recording a digital signal on a magnetic recording medium.

Currently, in order to realize a small size and a large capacity of a magnetic recording / reproducing apparatus, development of high recording density is being actively carried out. In the field of hard disk drives, which are typical magnetic recording / reproducing devices, devices whose surface recording density exceeds 30 Gbit / in ² (46.5 Mbit / mm ² ) have already been commercialized. The technology has advanced so rapidly that the practical use of a device having a density of 100 Gbit / in ² (155 Mbit / mm ² ) is predicted.

  As a technique for realizing such a high recording density, a tracking servo technique for a recording / reproducing head also plays an important role. The current tracking servo technology for magnetic recording media provides an area in which tracking servo signals, address information signals, reproduction clock signals, etc. are recorded (hereinafter referred to as “preformat recording”) at regular angular intervals on the magnetic recording medium. The magnetic head reproduces these signals at regular intervals, confirms the position of the magnetic head, and scans the track while correcting the position (for example, see Non-Patent Document 1).

  Since the tracking servo signal, the address information signal, the reproduction clock signal, and the like are reference signals for the magnetic head to accurately scan the track, accurate positioning accuracy is required at the time of recording. For this reason, conventionally, a magnetic recording medium is set in a dedicated servo recording device, and preformat recording is performed by a magnetic head whose position is strictly controlled (see, for example, Non-Patent Document 2).

  However, the conventional method of performing preformat recording using a dedicated servo recording device has the following problems. First, recording by the magnetic head is basically linear recording based on relative movement between the magnetic head and the magnetic recording medium, and therefore requires a lot of time for preformat recording. For this reason, a large number of expensive dedicated servo recording devices are required, which has been a factor in increasing costs for preformat recording. Second, due to the spacing between the head and the medium and the expansion of the recording magnetic field due to the pole shape of the recording head, there was a problem that the steepness of the magnetization transition at the track end portion where the preformat recording was performed was not good. When the magnetization transition lacks steepness, it becomes difficult to perform accurate tracking servo.

  As a method for solving the problems of the conventional preformat recording using a magnetic head, batch transfer is performed using a master information carrier in which a ferromagnetic thin film pattern corresponding to an information signal of preformat recording is formed on the surface of a substrate. A method has been proposed (see, for example, Patent Document 1). In this method, preformat recording is performed collectively on a magnetic recording medium by magnetizing a ferromagnetic thin film formed on the master information carrier while the surface of the master information carrier is in contact with the surface of the magnetic recording medium. . According to this method, good preformat recording is efficiently performed without sacrificing other important performances such as the S / N ratio and interface performance of the recording medium.

  In the above method using the master information carrier, the shape and pattern arrangement of the ferromagnetic thin film corresponding to the digital signal formed on the master information carrier are preformat recorded on the magnetic recording medium. Therefore, in order to obtain good magnetic signal characteristics, it is important that the pattern of the ferromagnetic thin film formed on the master information carrier is accurately formed. In order to form this pattern with high accuracy, the accuracy of the resist pattern formed on the master information carrier is very important.

  FIG. 9 is a cross-sectional view showing a step of forming a resist pattern in a conventional master information carrier. Hereinafter, this method will be described with reference to the drawings.

  As shown in FIG. 9A, a positive photoresist film 1200 is applied on the nonmagnetic substrate 1100. Next, as shown in FIG. 9B, a photomask 1300 on which a pattern for forming a vent groove is formed on the photoresist film 1200, and exposure is performed by irradiating with ultraviolet light 1400. . As a result, a region portion to be a vent groove for exposing the photoresist film 1200 is exposed. The irradiation amount of the ultraviolet light 1400 at this time is such that a part of the thickness of the photoresist film 1200 is exposed.

  Next, as shown in FIG. 9C, the photoresist film 1200 is developed. At this time, since the photosensitive region is up to a part of the thickness of the photoresist film 1200, the development can be performed in a state that does not reach the nonmagnetic substrate 1100. A groove 1210 is formed.

  Thereafter, as shown in FIG. 9D, a photomask 1500 on which a digital signal pattern is formed is disposed on the photoresist film 1200. At this time, vacuum suction is performed between the nonmagnetic substrate 1100 and the photomask 1500 by a vacuum suction device (not shown). When this vacuum suction is performed, air between the nonmagnetic substrate 1100 and the photomask 1500 is sucked through the vent groove 1210. As a result, the pattern formation region 1220 of the photoresist film 1200 formed on the surface of the nonmagnetic substrate 1100 and the photomask 1500 are strongly adhered to each other. After vacuum-contacting in this way, exposure is performed by irradiating with ultraviolet light 1400. The exposure amount of the ultraviolet light 1400 irradiated at this time is set to a light amount that ensures that the photoresist film 1200 is completely exposed.

  When the photoresist film 1200 is developed after exposure by such a method, a signal resist pattern 1600 corresponding to a digital signal that reaches the nonmagnetic substrate 1100 faithfully to the photomask 1500 is obtained. This state is shown in FIG.

  Thereafter, after forming a ferromagnetic thin film by sputtering or the like, an unnecessary ferromagnetic thin film is removed by performing a lift-off process. Thereby, a pattern of the ferromagnetic thin film corresponding to the digital signal is formed in the same region as the signal resist pattern 1600, and a master information carrier is obtained.

  In this case, in the case of a resist material having a characteristic capable of processing a micrometer order as a material of the photoresist film 1200, a pattern can be formed by such a method. However, in order to achieve a high recording density, it is required to form a pattern on the order of submicrometers with high accuracy. Photoresist materials that satisfy these requirements include chemically amplified photoresists and i-line photoresists.

  When using a chemically amplified photoresist material, the above method has the following problems. That is, in the above-described exposure method after forming the exhaust groove 1210 and bringing it into close contact, the exposure and development processing steps are performed twice for forming the exhaust groove 1210 and forming the signal resist pattern 1600. There is a need to do.

  FIG. 10 is a process cross-sectional view for explaining a problem when exposure and development are performed twice using this chemically amplified photoresist. FIG. 10A is a view showing a state in which a chemically amplified resist film 2200 is formed on the nonmagnetic substrate 1100. Next, as shown in FIG. 10B, a photomask 1300 on which a pattern for forming a vent groove is formed on the chemically amplified resist film 2200, and ultraviolet light 1400 is irradiated. A predetermined portion of the chemically amplified resist film 2200 is exposed. At this time, the irradiation amount of the ultraviolet light 1400 is set such that a part of the thickness of the chemically amplified resist film 2200 is exposed.

  Thereafter, as shown in FIG. 10C, when the chemically amplified resist film 2200 is developed, the photosensitive region reaches a part of the thickness of the chemically amplified resist film 2200, so that the nonmagnetic substrate 1100 is reached. It is possible to perform development in such a state that a vent groove 2210 as illustrated is formed, and the other region is a pattern formation region 2220.

  Next, as shown in FIG. 10 (d), a photomask 1500 on which a digital signal pattern is formed is placed on the chemically amplified resist film 2200, vacuum-adhered by the same method as described above, and then ultraviolet light. Exposure is performed by irradiating 1400. The exposure amount of the ultraviolet light 1400 irradiated at this time is set to a light amount that ensures that the thickness of the chemically amplified resist film 2200 is completely exposed.

  When the chemically amplified resist film 2200 is developed after exposure by such a method, the signal resist pattern 2260 corresponding to the digital signal that reaches the nonmagnetic substrate 1100 faithfully to the photomask 1500 in the pattern formation region 2220. Is obtained. However, the residual resist film 2240 that exists under the vent groove 2210 is also dissolved by the action of the acid catalyst during the development process. As a result, as shown in FIG. 10E, a concave groove 2215 that reaches the nonmagnetic substrate 1100 is formed.

  When the vent groove 2210 reaches the nonmagnetic substrate 1100 as described above, the lift-off process cannot be performed after the ferromagnetic thin film is formed. That is, since the ferromagnetic thin film remains in the vent groove 2210 even after lift-off, it becomes impossible to produce a master information carrier having a ferromagnetic thin film pattern corresponding to a digital signal.

  Further, when an i-line photoresist is used, a pattern abnormality occurs at both ends of the residual resist film existing under the evacuation groove. This will be described with reference to FIG. 11 and FIG.

  FIG. 11 shows the edge of the shielding portion when a photoresist film 3200 made of i-line photoresist is irradiated with ultraviolet light 1400 using a photomask 1300 on which a pattern for forming a vent groove is formed. It is a schematic diagram for demonstrating that light intensity distribution changes by diffraction and interference arising. FIG. 12 is a schematic cross-sectional view for explaining that square grooves are formed at both ends of the bleed groove when exposed as shown in FIG.

  As shown in FIG. 11A and FIG. 11B, the ultraviolet light 1400 is emitted from the shielding portion (A to B and C to D in the drawing) of the photomask 1300 and the light transmitting portion (in the drawing). In the edge portions B and C with the regions B to C), a region having a light intensity higher than that of the light transmitting portion is locally generated.

  For this reason, even if the light transmitting portion excluding the edge portions B and C has a condition in which only a part of the thickness of the photoresist film 3200 is exposed, the exposure amount is increased in the edge portions B and C. . As a result, when the development process is performed, a square groove 3240 as shown in FIG. 12 is formed only at both ends of the photoresist film 3200 below the vent groove 3210.

  FIGS. 12A and 12B show the case where the vent groove 3210 and the pattern formation region 3220 are formed on the photoresist film 3200 made of i-line photoresist formed on the surface of the nonmagnetic substrate 1100. It is a figure which shows the generating state of the square-shaped groove | channel 3240 which arises. As shown in FIG. 12, sharp and deep angular grooves 3240 are formed at both ends of the photoresist film 3200 of the vent groove 3210. Accordingly, the photoresist film 3200 cannot be thinned in order to form a finer digital signal pattern. When the film thickness is reduced, the angular grooves 3240 at the edge portions at both ends of the residual resist film 3260 reach the surface of the nonmagnetic substrate 1100. When the rectangular groove 3240 reaches the surface of the nonmagnetic substrate 1100, the lift-off process after forming the ferromagnetic thin film cannot be performed. That is, even if the lift-off process is performed, the ferromagnetic thin film in the portion of the square groove 3240 remains, and the master information carrier cannot be manufactured.

  For these reasons, the photoresist film 3200 cannot be made thin when an i-line photoresist is used. In addition, when trying to form a fine digital signal pattern resist pattern with a normal thickness, pattern defects such as falling due to the thick photoresist film are likely to occur. Further, since the square groove 3240 at the edge portion is formed, the depth of the vent groove 3210 cannot be increased. Therefore, there is a problem that the conductance of the exhaust gas in the vent groove 3210 is reduced, and it is difficult to sufficiently adhere the photomask 1300 on which the digital signal pattern is formed to the photoresist film 3200.

As described above, a chemically amplified resist or the like capable of forming a pattern on the order of submicrometers cannot be used in the conventional method. For this reason, the wavelength of the light source and the resist material characteristics cannot be matched. It was not possible.
JP 10-40544 A Yamaguchi: High-precision servo technology for magnetic disk drives, Journal of Japan Society of Applied Magnetics, Vol. 20, no. 3, pp 771, 1996 Uematsu, et al .: Mechanics and servos, current status and future prospects of HDI technology, Japan Society of Applied Magnetics, 93rd Research Materials, 93-5, pp. 35, 1996

  As described above, when a resist pattern is formed using a conventional chemically amplified photoresist or i-line photoresist, the evacuation concave groove reaches the non-magnetic substrate, and the ferromagnetic thin film is predetermined. Pattern abnormalities occur, such as the formation of the above pattern, or the formation of square grooves at the edge portions at both ends of the vent groove. For this reason, a fine resist pattern cannot be formed with high accuracy.

  In order to solve the above-described problems, the present invention provides a photoresist coating method for accurately forming a resist pattern on a substrate surface, a resist pattern forming method using the photoresist coating method, and a master information carrier that is compatible with information signals. It is an object of the present invention to provide a method for producing a master information carrier capable of accurately forming a pattern made of a magnetic thin film.

  In order to solve the above problems, a photoresist coating method of the present invention is a method for forming a thin film pattern having a preset shape on the surface of a substrate, and is a photoresist in a pattern forming region for forming a thin film pattern. The thickness of the film is thicker than that of the non-formation region where the thin film pattern is not formed, and the non-formation region is continuously formed from the center to the outer periphery of the substrate.

  By this method, a non-formation area where a thin film pattern is not formed is continuously formed on the surface of the substrate from the central portion to the outer peripheral portion of the substrate. The non-formation region acts as a bleed groove, and the photomask and the pattern formation region of the photoresist film formed on the surface of the substrate can be uniformly adhered over the entire surface. As a result, a resist pattern having a high precision and a fine shape can be formed.

  In the above method, the photoresist is quantitatively discharged from the discharge nozzle while maintaining a certain distance from the surface of the substrate, and the photoresist is applied onto the surface of the substrate by relatively moving the substrate and the discharge nozzle. May be.

  Further, in this case, when the photoresist film is formed by discharging a certain amount of photoresist by the discharge nozzle, the discharge time in the pattern formation region may be longer than the discharge time in the non-formation region. Alternatively, the number of ejections in the pattern formation region may be greater than the number of ejections in the non-formation region.

  Furthermore, when applying a photoresist using a discharge nozzle, using photoresists adjusted to different viscosities, a photoresist having a high viscosity is discharged in a pattern formation region and a photoresist having a low viscosity in a non-formation region. It is good also as a method of discharging.

  In addition, when applying a photoresist using a discharge nozzle, a photoresist having a different viscosity is used to discharge a low-viscosity photoresist onto the surface of the substrate to form a thin photoresist film. Alternatively, a photoresist having a high viscosity may be discharged to the pattern formation region.

  Alternatively, the photoresist is uniformly applied to the entire surface of the substrate while rotating the substrate, and the photoresist is discharged from the discharge nozzle while maintaining a certain distance with respect to the surface of the substrate. Alternatively, the photoresist may be further applied to the pattern forming region of the substrate.

  By adopting such a method, a photoresist film having a predetermined thickness can be easily formed in a pattern formation region at an arbitrary position on the substrate. For example, if photoresists having different viscosities are used, a thick photoresist film can be formed in a region where a photoresist having a high viscosity is discharged and a thin region in a region where a photoresist having a low viscosity is discharged. For example, when an inkjet head is used as the ejection nozzle and a resist solution is ejected from the inkjet head, the resist ejection time from the inkjet head may be lengthened, the number of ejections may be increased, or the viscosity of the photoresist may be increased. . In this way, it can be easily formed thick only in a predetermined pattern formation region.

  In addition, if a thin photoresist film is formed on the surface of the substrate by a normal spin coating method and then a photoresist is further applied to a region to be a pattern formation region using an inkjet head, only the pattern formation region has a predetermined thickness. be able to. As described above, various photoresist materials can be used to form the non-formation region at the time of applying the resist. Further, since the thickness of the photoresist film can be precisely controlled, the thickness of the pattern formation region and the thickness of the non-formation region can be easily controlled. Furthermore, since exposure and development are not performed twice as in the prior art, pattern abnormality does not occur even when a chemically amplified photoresist or i-line photoresist is used.

  The resist pattern forming method of the present invention is a method for forming a resist pattern corresponding to a photomask by bringing a photomask and a substrate on which a photoresist film is formed into close contact with each other and exposing the photomask. After the resist coating process for forming a photoresist film on the surface of the substrate by the method and the space formed by the holding table and the photomask for holding the substrate are hermetically sealed, vacuum exhaust is performed using the non-formed region as an exhaust path. Thus, the pattern forming region and the photomask are brought into close contact with each other and exposed.

  By this method, vacuum contact exposure between the pattern formation region of the photoresist film and the photomask can be easily performed. That is, in the photoresist film formed on the surface of the substrate, the non-formation region is concave compared to the pattern formation region. By evacuating this region as a vent groove, the pattern formation region and the photo resist region are exposed. A close contact with the mask can be achieved. As described above, when the pattern formation region is exposed through the photomask after being in a high adhesion state, it is possible to prevent light from wrapping around. As a result, pattern defects caused by light diffraction can be avoided, and a resist pattern can be formed with high accuracy.

  Also, in the method of manufacturing a master information carrier for recording a digital signal on a magnetic recording medium in contact with the magnetic recording medium of the present invention, a photoresist film is formed on the surface of a nonmagnetic substrate by the above-described photoresist coating method. And a photomask having a pattern corresponding to a digital signal disposed on the surface of the nonmagnetic substrate, and the space formed by the holding table for holding the nonmagnetic substrate and the photomask is airtight. Then, the pattern formation region and the photomask are in close contact with each other and exposed by evacuating the non-formation region as an exhaust path, and the resist pattern corresponding to the digital signal is developed by developing the photoresist film. And a non-magnetic group including a photoresist film on which a resist pattern is formed Depositing a ferromagnetic thin film on the surface of the substrate and removing the ferromagnetic thin film deposited on the surface of the photoresist film together with the photoresist film to form a ferromagnetic thin film pattern corresponding to a digital signal on the surface of the nonmagnetic substrate The method which has these.

  Also, in the method of manufacturing a master information carrier for recording a digital signal on a magnetic recording medium in contact with the magnetic recording medium of the present invention, a photoresist film is formed on the surface of a nonmagnetic substrate by the above-described photoresist coating method. And a photomask having a pattern corresponding to a digital signal disposed on the surface of the nonmagnetic substrate, and the space formed by the holding table for holding the nonmagnetic substrate and the photomask is airtight. Then, the pattern formation region and the photomask are in close contact with each other and exposed by evacuating the non-formation region as an exhaust path, and the resist pattern corresponding to the digital signal is developed by developing the photoresist film. And a photoresist film on which a resist pattern is formed as a mask Etching the magnetic substrate to form a buried groove of a pattern shape corresponding to a digital signal in the non-magnetic substrate in the pattern formation region; and forming the buried groove and then forming a ferromagnetic thin film on the surface of the non-magnetic substrate including the photoresist film And a step of removing the ferromagnetic thin film deposited on the surface of the photoresist film together with the photoresist film and forming a ferromagnetic thin film pattern corresponding to the digital signal in the buried groove of the nonmagnetic substrate. Become.

  Furthermore, a method for manufacturing a master information carrier for recording a digital signal on a magnetic recording medium in contact with the magnetic recording medium of the present invention includes a step of depositing a ferromagnetic thin film on the surface of a nonmagnetic substrate, and the photoresist described above. A step of forming a photoresist film on the surface of the ferromagnetic thin film of the nonmagnetic substrate by a coating method, and a photomask on which a pattern corresponding to a digital signal is formed are disposed on the surface of the nonmagnetic substrate and the nonmagnetic substrate is held. After the space formed by the holding table and the photomask is hermetically sealed, the pattern formation region and the photomask are closely contacted and exposed by evacuating the non-formation region as an exhaust path, and the photoresist film is developed. Forming a resist pattern corresponding to the digital signal in the pattern formation region, and a photoresist film Forming a thin film pattern corresponding to a digital signal by etching the ferromagnetic thin film in the disk, it comprises a method and a step of removing the photoresist film.

  By such a method, a thin film pattern made of a ferromagnetic thin film can be formed with high accuracy by a lift-off process or an etching process. Further, a thin film pattern can be embedded in the nonmagnetic substrate.

  As a method for depositing the ferromagnetic thin film on the surface of the nonmagnetic substrate, for example, a sputtering method or a vapor deposition method can be used. In addition, as the etching of the ferromagnetic thin film, it is preferable to use a reactive ion etching method or an ion milling method.

  Moreover, according to the photoresist coating method of the present invention, various resist materials can be used, and the photoresist film thickness can be precisely controlled. For this reason, it is possible to control the thickness of the pattern formation region and the non-formation region with high accuracy, and thus it is possible to form the resist pattern with high accuracy. Furthermore, pattern exposure in a high adhesion state is possible, light wraparound can be prevented, pattern defects can be avoided, and a resist pattern can be formed with high accuracy.

  By using the photoresist coating method and the resist pattern forming method of the present invention, the adhesion between the photomask and the pattern formation region of the photoresist film can be greatly enhanced. For example, a resist pattern representing an information signal having a submicron shape. Even so, it can be formed with high accuracy. Therefore, a master information carrier requiring a high recording density can be easily manufactured. In this way, a great effect is achieved that a resist pattern requiring submicron can be easily formed with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram schematically illustrating a configuration example of a coating apparatus used in the photoresist coating method according to the first embodiment of the present invention. The photoresist coating apparatus includes a holding table 2 for holding a substrate 11, a substrate moving mechanism (not shown), a discharge nozzle 3, a resist supply unit 4 for supplying a photoresist 5 to the discharge nozzle 3, a substrate 11 and a discharge nozzle 3, It is comprised by the control part (not shown) which controls operation | movement of the resist supply part 4 grade | etc.,.

  Various driving means for moving the base 11 and the discharge nozzle 3 can be used. For example, a driving mechanism using a stepping motor or the like may be used. The discharge nozzle 3 can be used without any limitation as long as it has a configuration capable of quantitatively discharging a liquid such as a photoresist, such as an inkjet head or a drawing nozzle. In the case of using an ink jet head, for example, a piezoelectric body type in which a piezoelectric element made of PZT vibrates a diaphragm and a resist is ejected by the vibration may be used. In this method, the substrate 11 is not limited to the disc shape as shown in FIG.

  FIG. 2 is a partial perspective view schematically showing a state in which the photoresist film 12 is formed on the surface of the disk-shaped substrate 11 using the photoresist coating apparatus shown in FIG. As shown in FIGS. 1 and 2, the disc-shaped base 11 fixed to the holding table 2 is moved as shown by an arrow 90 and the discharge nozzle 3 is moved as shown by an arrow 92 by a base movement mechanism (not shown). . When the photoresist 5 is supplied from the resist supply unit 4 and the photoresist 5 is discharged from the discharge nozzle 3 during this movement, the preset pattern formation region 121 on the surface of the substrate 11 is thick, and is not formed between them. A photoresist film 12 having a thin region 122 is obtained.

  In this case, the timing and amount of discharging the photoresist 5 are controlled by a control unit (not shown). For example, if the number of times of discharging the photoresist when forming the pattern formation region 121 shown in FIG. 2 is made larger than the number of discharging times in the non-formation region 122, or if the discharge time is made longer, the photoresist in this region is made thicker. Can do.

  When quantitatively discharging a photoresist using a discharge nozzle, a photoresist having a different viscosity is used to discharge a photoresist having a high viscosity in the pattern formation region, and a photoresist having a low viscosity in a non-formation region. A resist may be discharged. In this case, it is desirable to use different discharge nozzles for the high viscosity photoresist and the low viscosity photoresist.

  In addition, when applying a photoresist using a discharge nozzle, a photoresist having a different viscosity is used to discharge a low-viscosity photoresist onto the surface of the substrate to form a thin photoresist film. Alternatively, a photoresist having a high viscosity may be discharged to the pattern formation region.

  Furthermore, the photoresist is uniformly applied to the entire surface of the substrate while rotating the substrate, and the photoresist is discharged from the discharge nozzle while maintaining a certain distance from the surface of the substrate. It is also possible to form a photoresist film with a thick pattern formation region and a thin non-formation region by applying a photoresist to the pattern formation region of the substrate.

  By such an application method, it becomes possible to finely apply a desired photoresist material to a local region on the substrate 11 under desired conditions. In addition, a photoresist film having a thickness suitable for each region can be formed. Furthermore, since there is no restriction on the photoresist material for this formation, a resist material optimum for the process can be used.

  In the photoresist coating method of the present invention, the number of discharge nozzles is not limited to one, and a plurality of discharge nozzles can be used. By using a plurality of discharge nozzles, it is possible to apply a photoresist to a plurality of regions at the same time and use photoresist materials having different viscosities.

  In the present embodiment, the base is a disk, but the present invention is not limited to this. For example, a rectangular flat plate may be used, and the shape is not limited.

(Second Embodiment)
FIG. 3 is a cross-sectional view for explaining the outline of the resist pattern forming method according to the second embodiment of the present invention. In the present embodiment, a photoresist having a pattern formation region 121 and a non-formation region 122 on the surface of a disk-shaped substrate 11 as shown in FIG. 2 using the photoresist coating method described in the first embodiment. A case where a predetermined resist pattern is formed on the film 12 will be described.

  FIG. 3A is a cross-sectional view of a state in which a photoresist film 12 having irregularities is formed on the surface of the substrate 11 by using the photoresist coating method of the first embodiment. That is, in the present embodiment, a non-formation region where a fine pattern is not formed in the photoresist film 12 is a concave groove, and this region becomes a vent groove 122. Note that both sides of the vent groove 122 are pattern formation regions 121 for forming a fine pattern, and the photoresist is formed thick. Note that a photoresist film is provided below the vent groove 122 and has a bottomed shape. In the production of the photoresist film 12 having such a shape, a photolithography process is not required at all unlike the conventional method.

  Next, as shown in FIG. 3B, the substrate 11 is placed on the substrate holder 71, and a photomask 15 on which a predetermined fine pattern 151 is formed is applied to the photoresist film 12 on the surface of the substrate 11. Contact. In this case, mask alignment is performed so that the region where the fine pattern 151 of the photomask 15 is formed is positioned on the pattern formation region 121 of the photoresist film 12.

  Next, as shown in FIG. 3C, for example, a seal rubber 72 is sandwiched between the outer peripheral region of the photomask 15 and the outer peripheral region of the substrate holder 71, so that a space between the photomask 15 and the substrate holder 71 is formed. Seal. After this, the vacuum evacuation is performed by a vacuum pump (not shown) through the exhaust hole 711 provided in the base holder 71. In this evacuation, since the vent groove 122 of the photoresist film 12 serves as an air flow path, the entire area between the photoresist film 12 and the photomask 15 is evacuated uniformly. As a result, the photomask 15 and the pattern formation region 121 can be uniformly and satisfactorily adhered over the entire surface. After making such a close contact state, exposure is performed by irradiating with ultraviolet light 14.

  After the exposure, if the substrate 11 is taken out and developed, a resist pattern 16 having a fine shape faithful to the photomask 15 can be formed. The state in which the resist pattern 16 is formed in this way is shown in FIG.

  By adopting such a resist pattern forming method, an air flow path can be formed by the evacuation concave groove 122, and uniform vacuuming can be performed over the entire surface, so that the adhesion of the photomask 15 to the pattern forming region 121 is increased, And uniform. As a result, when the ultraviolet light 14 is irradiated, the wraparound of light due to diffraction or the like can be prevented, and even a fine pattern shape can be formed with high accuracy.

(Third embodiment)
In the present embodiment, a method for manufacturing a master information carrier using the above-described photoresist coating method and resist pattern forming method will be described.

  First, an outline of the master information carrier will be described. FIG. 4 is a plan view schematically showing the master information carrier 20. The master information carrier 20 is an example of what is used for recording a signal on a hard disk. In the master information carrier 20, signal regions 24 are formed radially on the main surface of the nonmagnetic substrate 22 from the center as shown in the figure. A schematic diagram of the pattern shape of the signal region 24 is shown in FIG. FIG. 5 is an enlarged view of a portion A surrounded by a dotted line in FIG. 4, and is an example in the case of recording a servo signal. As shown in FIG. 5, a ferromagnetic thin film 26 as a master information pattern is formed in a predetermined shape in the signal area 24 at a position corresponding to a digital information signal recorded on a magnetic recording medium. Examples of the master information pattern include a tracking servo signal and an address information signal. In FIG. 5, the hatched portion is a portion formed by the ferromagnetic thin film 26.

  FIG. 5 shows a master information pattern for 10 tracks in the radial direction of the master information carrier 20 (that is, in the track width direction). For reference, a track portion that becomes a data area on the magnetic recording medium after the master information pattern is transferred and recorded on the magnetic recording medium is indicated by a one-dot chain line.

  Corresponding to the digital information signal recorded on the magnetic recording medium, the signal area 24 of the master information carrier 20 has a certain angle in the circumferential direction and the entire recording track in the radial direction, as shown in FIG. A master information pattern is formed.

  When the master information pattern is a servo pattern, for example, as shown in FIG. 5, each area of a clock signal, a tracking servo signal, an address information signal, etc. is sequentially arranged in the track length direction. Yes. 4 and 5 are examples, and the configuration and arrangement of the master information pattern may be changed as appropriate in accordance with the digital information signal recorded on the magnetic recording medium. Further, as the nonmagnetic substrate 22 used for the master information carrier 20, for example, a glass substrate, a plastic substrate, a Si substrate, or the like can be used.

  The ferromagnetic thin film 26 may be made of a ferromagnetic material and can transfer and record a signal on a magnetic recording medium. For example, Fe, Co, Fe—Co alloy, or the like can be used. As described above, the ferromagnetic thin film 26 is formed at a position corresponding to a digital information signal (for example, preformat recording) recorded on the magnetic recording medium.

  Next, an example of a method for manufacturing the master information carrier will be described. FIG. 6 is a cross-sectional view of main steps for explaining an example of a method for producing a master information carrier having the above-described configuration.

  As shown in FIG. 6A, a photoresist film 28 is applied on the surface of the disk-shaped nonmagnetic substrate 22 by the photoresist coating method described in the first embodiment. In this case, the thickness of the photoresist film 28 in the pattern formation region 281 to be the signal region 24 is formed to be thicker than the vent groove 282. As can be seen from FIG. 4, the vent groove 282 is continuously formed from the center to the outer periphery of the non-magnetic substrate 22 and serves as an air flow path when vacuum-adhering. This vent groove 282 is a non-forming region.

  Next, as shown in FIG. 6B, the photomask 30 on which the pattern 302 corresponding to the digital signal is formed is disposed on the photoresist film 28 of the nonmagnetic substrate 22, and the pattern 302 corresponding to the digital signal is formed. Alignment with the pattern formation region 281 of the photoresist film 28 is performed. The pattern 302 is a pattern corresponding to a digital signal such as an information signal for tracking servo to be magnetically transferred to a disk-shaped magnetic recording medium (hard disk).

  After such arrangement, based on the resist pattern forming method described in the second embodiment, the outer periphery of the photomask 30 and the outer periphery of the substrate holder (not shown) are sandwiched with, for example, seal rubber, and the photomask 30 and the substrate Seal the space between the holder. After this, evacuation is performed by a vacuum pump (not shown) through an exhaust hole provided in the base holder. In this evacuation, since the vent groove 282 of the photoresist film 28 serves as an air flow path, the entire area between the photoresist film 28 and the photomask 30 is evacuated uniformly. As a result, the photomask 30 and the pattern formation region 281 can be uniformly and satisfactorily adhered over the entire surface. After making such a close contact state, exposure is performed by irradiating with ultraviolet light 32.

  After the exposure, the nonmagnetic substrate 22 is taken out and developed to form a resist pattern 284 having a fine shape faithfully to the photomask 30. FIG. 6C shows a state in which the resist pattern 284 is formed in this way.

  By adopting such a resist pattern forming method, an air flow path can be formed by the vent groove 282, and uniform vacuuming can be performed over the entire surface, so that the adhesion of the photomask 30 to the pattern formation region 281 is increased, And uniform. As a result, when the ultraviolet light 32 is irradiated, the wraparound of light due to diffraction or the like can be prevented, and even a fine pattern shape can be formed with high accuracy. The resist pattern 284 exposes the surface of the nonmagnetic substrate 22 in the region where the pattern of the ferromagnetic thin film 26 shown in FIG. 5 is formed.

  Next, as shown in FIG. 6D, a ferromagnetic thin film 26 is deposited on the surface of the nonmagnetic substrate 22 including the photoresist film 28.

  Thereafter, as shown in FIG. 6E, the ferromagnetic thin film 26 adhering to the surface of the photoresist film 28 is removed by dissolving the photoresist film 28 using a developer or solution such as an organic solvent. Is done. This method is generally called lift-off.

  As described above, the master information carrier 20 having the pattern shape corresponding to the information signal made of the ferromagnetic thin film 26 in the signal region 24 of the nonmagnetic substrate 22 is obtained.

  According to the present embodiment, the photoresist film 28 is exposed to the ultraviolet light 32 in a state where the close contact between the pattern formation region 281 and the photomask 30 is strengthened by evacuation through the evacuation concave groove 282. Therefore, it is possible to reliably prevent the wraparound of light during exposure. As a result, the resist pattern 284 is free from side wall taper and the like, and a shape faithful to the pattern 302 corresponding to the digital signal of the photomask 30 can be obtained. Therefore, a fine and highly accurate pattern of the ferromagnetic thin film 26 can be obtained, and a master information carrier that can cope with high-density recording as compared with the prior art can be manufactured.

  FIG. 7 is a cross-sectional view of the main steps for explaining the method of the first modification of the method for manufacturing a master information carrier according to the present embodiment.

  As shown in FIG. 7A, a ferromagnetic thin film 26 is deposited on the surface of a disk-like nonmagnetic substrate 22.

  Next, as shown in FIG. 7B, the pattern forming region 341 is thick and the vent groove 342 is thin on the surface of the ferromagnetic thin film 26 by the photoresist coating method of the first embodiment. A photoresist film 34 is formed. The vent groove 342 is a non-formed region.

  Next, as shown in FIG. 7C, a photomask 36 on which a pattern 361 corresponding to a digital signal is formed is disposed on the photoresist film 34 of the nonmagnetic substrate 22, and a pattern 361 corresponding to the digital signal is formed. The photoresist film 34 is aligned with the pattern formation region 341. In the case of the first modification, the pattern 361 corresponding to the digital signal of the photomask 36 has a reverse pattern relationship with the photomask 30 described in FIG.

  After this arrangement, evacuation is performed from the outer periphery of the photoresist film 34 through the vent groove 342 as in the present embodiment. This sufficiently increases the adhesion between the photomask 36 and the pattern formation region 341 of the photoresist film 34. Exposure is performed in this strong contact state.

  After the exposure, the nonmagnetic substrate 22 is taken out and developed to form a resist pattern 344 having a fine shape faithfully to the photomask 36. The state in which the resist pattern 344 is formed in this way is shown in FIG. A resist pattern 344 is formed at a position corresponding to the pattern 361 of the photomask 36.

  Next, as shown in FIG. 7E, the ferromagnetic thin film 26 is etched using the resist pattern 344 as a mask. As an etching method, for example, an ion milling method or a reactive ion etching method can be used.

  Next, as shown in FIG. 7F, the resist pattern 344 is dissolved and removed using a developing solution such as an organic solvent or a dissolving solution. As a result, a master information carrier having a pattern shape corresponding to the information signal made of the ferromagnetic thin film 26 in the signal region 24 of the nonmagnetic substrate 22 is obtained.

  According to the first modification, exposure is performed in a state where the close contact between the pattern formation region 341 and the photomask 36 is strengthened by evacuation through the concave groove 342 for extraction. Can be reliably prevented. As a result, the resist pattern 344 is free from side wall taper and the like, and a shape faithful to the pattern 361 corresponding to the digital signal of the photomask 36 can be obtained. Therefore, a fine and highly accurate pattern of the ferromagnetic thin film 26 can be obtained, and a master information carrier that can cope with high-density recording as compared with the prior art can be manufactured.

  FIG. 8 is a cross-sectional view of the main steps for explaining the method of the second modification of the method for manufacturing a master information carrier according to the present embodiment.

  Since FIG. 8A to FIG. 8C are the same as FIG. 6A to FIG. 6C, description thereof will be omitted.

  As shown in FIG. 8C, after forming the resist pattern 284 corresponding to the digital signal, the nonmagnetic substrate 22 is placed in an etching apparatus, and the resist pattern 284 is used as a mask as shown in FIG. A predetermined amount of the nonmagnetic substrate 22 is etched. By this etching, an embedding recess 221 having a pattern corresponding to the information signal is formed in the nonmagnetic substrate 22.

  Next, as shown in FIG. 8E, a ferromagnetic thin film 26 is deposited on the surface of the nonmagnetic substrate 22 including the photoresist film 28.

  Next, as shown in FIG. 8F, an unnecessary ferromagnetic thin film is removed by a lift-off process. That is, the photoresist film 28 is dissolved using a developing solution or a solution such as an organic solvent, thereby simultaneously removing the ferromagnetic thin film 26 attached to the surface of the photoresist film 28.

  As described above, a master information carrier in which the pattern shape corresponding to the information signal composed of the ferromagnetic thin film 26 is embedded in the signal region 24 of the nonmagnetic substrate 22 is obtained.

  According to the manufacturing method of the second modification, exposure is performed in a state where the close contact between the pattern formation region 281 and the photomask 30 is strengthened by evacuation through the vent groove 282. It is possible to reliably prevent light from wrapping around during exposure. As a result, the resist pattern 284 is free from side wall taper and the like, and a shape faithful to the pattern 302 corresponding to the digital signal of the photomask 30 can be obtained. Therefore, a fine and highly accurate pattern of the ferromagnetic thin film 26 can be obtained, and a master information carrier that can cope with high-density recording as compared with the prior art can be manufactured. In addition, in this method, the ferromagnetic thin film 26 having a pattern shape corresponding to the information signal can be formed in a state of being embedded in the nonmagnetic substrate 22, so that a long-life master information carrier can be realized.

  After preformat recording on a magnetic recording medium using the master information carrier produced by the above manufacturing method, the signal recorded on the magnetic recording medium was read by a head and the signal was evaluated. As a result, it was confirmed that the signal as designed was recorded until the line width of the pattern of the ferromagnetic thin film was 0.3 μm. On the other hand, in the case of a master information carrier manufactured by a conventional method, a reproduction signal as designed cannot be obtained if the line width of the pattern is 0.5 μm.

  As mentioned above, although the manufacturing method of embodiment of this invention was demonstrated including the modification, this invention is not limited to these embodiment, It applies to other embodiment based on the technical idea of this invention. can do.

  For example, in the above embodiment, a master information carrier for transferring and recording a digital information signal on a magnetic recording medium mainly mounted on a hard disk drive or the like has been described. However, the master information carrier of the present invention is a flexible magnetic disk, magnetic It can also be applied to magnetic recording media such as cards and magnetic tapes.

  In the above embodiment, the case where the information signal recorded on the magnetic recording medium is a preformat signal including a tracking servo signal, an address information signal, a reproduction clock signal, etc. has been described. The master information carrier of the present invention can also be used for recording. For example, various data signals, audio and video signals can be recorded using the master information carrier of the present invention. In this case, the master information carrier of the present invention and the recording technology to the magnetic recording medium using the same can be used for mass production of soft disk media, and the soft disk media can be provided at low cost. It is.

  Further, it can be applied as a process of a pattern forming method for a semiconductor or an optical disk.

  The photoresist coating method, the resist pattern forming method and the master information carrier manufacturing method using the photoresist coating method of the present invention can form a resist pattern on the substrate surface with high accuracy, and a resist using the photoresist coating method. A pattern of a ferromagnetic thin film corresponding to an information signal can be accurately formed by a pattern forming method, and is useful in the field of magnetic recording.

The figure which shows typically the structural example of the coating device used in the photoresist coating method concerning the 1st Embodiment of this invention. In the same embodiment, a partial perspective view schematically showing a state in which a photoresist film is formed on the surface of a disk-shaped substrate Sectional drawing explaining the outline | summary of the resist pattern formation method concerning the 2nd Embodiment of this invention The top view which showed typically the master information carrier in the manufacturing method of the master information carrier concerning the 3rd Embodiment of this invention Schematic diagram of pattern shape of signal area in the same embodiment Sectional drawing of the main process for demonstrating an example of the manufacturing method of the master information carrier in the embodiment Sectional drawing of the main process explaining the method of the 1st modification of the manufacturing method of the master information carrier concerning the embodiment Sectional drawing of the main process explaining the method of the 2nd modification of the manufacturing method of the master information carrier concerning the embodiment Sectional drawing which shows the process of forming a resist pattern in the conventional master information carrier Process cross-sectional view for explaining the problem of exposure and development twice using a chemically amplified photoresist When irradiating ultraviolet light onto a photoresist film made of i-line photoresist using a photomask on which a pattern for forming a vent groove is formed, diffraction and interference occur at the edge of the shielding part. Schematic diagram for explaining that the light intensity distribution changes FIG. 11 is a schematic cross-sectional view for explaining that square grooves are formed at both ends of the vent groove when exposed as shown in FIG.

Explanation of symbols

2 Holding stand 3 Discharge nozzle 4 Resist supply unit 5 Photoresist 11 Base 12, 28, 34, 1200, 3200 Photoresist film 14, 32, 1400 Ultraviolet light 15, 30, 36, 1300, 1500 Photomask 16, 284, 344 Resist pattern 20 Master information carrier 22, 1100 Non-magnetic substrate 24 Signal region 26 Ferromagnetic thin film 71 Base holder 72 Seal rubber 121,281,341,1220,2220,3220 Pattern formation region 122,282,342,1210,2210,3210 Careful ditch (non-forming area)
151, 302, 361 Pattern 221 Embedding recess 711 Exhaust hole 1600, 2260 Signal resist pattern 2200 Chemically amplified resist film 2215 Concave groove 2240, 3260 Residual resist film 3240 Square groove

Claims (11)

A photoresist coating method for forming a thin film pattern having a preset shape on the surface of a substrate,
The film thickness of the photoresist film in the pattern formation region for forming the thin film pattern is thicker than that in the non-formation region where the thin film pattern is not formed, and the non-formation region is continuous from the center to the outer periphery of the substrate. And forming a photoresist. While keeping a certain distance from the surface of the substrate, the photoresist is quantitatively discharged from the discharge nozzle, and the substrate and the discharge nozzle are relatively moved to apply the photoresist onto the surface of the substrate. The photoresist coating method according to claim 1. 3. The discharge time in the pattern formation region is made longer than the discharge time in the non-formation region when the photoresist film is formed by discharging a predetermined amount of the photoresist by the discharge nozzle. The photoresist coating method as described. 3. The number of ejections in the pattern formation region is made larger than the number of ejections in the non-formation region when the photoresist film is formed by ejecting a predetermined amount of the photoresist by the ejection nozzle. The photoresist coating method as described. When the photoresist is applied using the discharge nozzle, the photoresist having a different viscosity is used to discharge the photoresist having a high viscosity in the pattern formation region, and the viscosity in the non-formation region. 3. The photoresist coating method according to claim 2, wherein the small photoresist is discharged. When applying the photoresist using the discharge nozzle, a thin photoresist film is formed by discharging the photoresist having a low viscosity onto the surface of the substrate using photoresists adjusted to different viscosities. 3. The photoresist coating method according to claim 2, wherein the photoresist having a high viscosity is discharged to the pattern formation region. Applying the photoresist uniformly over the entire surface of the substrate while rotating the substrate;
The photoresist is discharged from the discharge nozzle while maintaining a certain distance with respect to the surface of the substrate, and the photoresist and the discharge nozzle are relatively moved to further move the photoresist to the pattern forming region of the substrate. The photoresist coating method according to claim 1, wherein the photoresist is coated. A method of forming a resist pattern corresponding to the photomask by exposing a photomask and a substrate on which a photoresist film is formed to be exposed,
A resist coating step for forming the photoresist film on the surface of the substrate by the photoresist coating method according to any one of claims 1 to 7,
After the space formed by the holding table for holding the substrate and the photomask is airtight, the pattern formation region and the photomask are brought into close contact with each other by evacuating the non-formation region as an exhaust path. And a resist pattern forming method. A method of manufacturing a master information carrier for recording a digital signal on the magnetic recording medium in contact with the magnetic recording medium,
A resist coating process for forming the photoresist film on the surface of the nonmagnetic substrate by the photoresist coating method according to claim 1,
A photomask on which a pattern corresponding to the digital signal is formed is disposed on the surface of the nonmagnetic substrate, and a space formed by the holding table for holding the nonmagnetic substrate and the photomask is airtight. And exposing the pattern formation region and the photomask in close contact by evacuating the non-formation region as an exhaust path; and
Forming a resist pattern corresponding to the digital signal in the pattern forming region by developing the photoresist film;
Depositing a ferromagnetic thin film on the surface of the non-magnetic substrate including the photoresist film on which the resist pattern is formed;
Removing the ferromagnetic thin film deposited on the surface of the photoresist film together with the photoresist film, and forming a ferromagnetic thin film pattern corresponding to the digital signal on the surface of the nonmagnetic substrate. A method for producing a master information carrier. A method of manufacturing a master information carrier for recording a digital signal on the magnetic recording medium in contact with the magnetic recording medium,
A resist coating process for forming the photoresist film on the surface of the nonmagnetic substrate by the photoresist coating method according to claim 1,
A photomask on which a pattern corresponding to the digital signal is formed is disposed on the surface of the nonmagnetic substrate, and a space formed by the holding table for holding the nonmagnetic substrate and the photomask is airtight. And exposing the pattern formation region and the photomask in close contact by evacuating the non-formation region as an exhaust path; and
Forming a resist pattern corresponding to the digital signal in the pattern forming region by developing the photoresist film;
Etching the non-magnetic substrate using the photoresist film on which the resist pattern is formed as a mask to form a buried groove having a pattern shape corresponding to the digital signal in the non-magnetic substrate in the pattern formation region;
Depositing a ferromagnetic thin film on the surface of the nonmagnetic substrate including the photoresist film after forming the buried trench;
Removing the ferromagnetic thin film deposited on the surface of the photoresist film together with the photoresist film, and forming a ferromagnetic thin film pattern corresponding to the digital signal in the buried groove of the nonmagnetic substrate. A method for producing a master information carrier. A method of manufacturing a master information carrier for recording a digital signal on the magnetic recording medium in contact with the magnetic recording medium,
Depositing a ferromagnetic thin film on the surface of the non-magnetic substrate;
Forming the photoresist film on the ferromagnetic thin film surface of the nonmagnetic substrate by the photoresist coating method according to claim 1;
A photomask on which a pattern corresponding to the digital signal is formed is disposed on the surface of the nonmagnetic substrate, and a space formed by the holding table for holding the nonmagnetic substrate and the photomask is airtight. And exposing the pattern formation region and the photomask in close contact by evacuating the non-formation region as an exhaust path; and
Forming a resist pattern corresponding to the digital signal in the pattern forming region by developing the photoresist film;
Etching the ferromagnetic thin film using the photoresist film as a mask to form a thin film pattern corresponding to the digital signal;
And a step of removing the photoresist film. A method for producing a master information carrier.

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