JP2009020961A - Manufacturing method of optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently enhancing peeling stability of an intermediate layer and a stamper, without newly increasing procedures, in a multilayering step of an optical information recording medium. <P>SOLUTION: After an information recording layer is film-deposited on a substrate provided with a guide groove or an information pit provided therein, a UV curable resin is applied, stuck to a stamper having the inside diameter larger than the inside diameter of the substrate and is cured by UV, in such a state that the UV-curable resin is protruded from a center hole of the stamper, and the UV cured resin protruded from the center hole of the stamper is pushed up from the inner periphery, while being pressed down by a center pin and peeled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical information recording medium having a plurality of information recording layers.

  Currently, there is a demand for increasing the capacity of optical information recording media. As a means for meeting the demand, there is a method in which the information recording layer has a multilayer structure. When the information recording layer has a multilayer structure, an intermediate layer is formed between the information recording layers.

  For forming the intermediate layer, a method is widely used in which an ultraviolet curable resin is applied and spread, bonded to a stamper, cured with ultraviolet rays, and peeled off. In order to facilitate the peeling process in this method, the stamper has an inner diameter larger than the inner diameter of the substrate. When actually peeling, the stamper is fixed and smaller than the stamper inner diameter and larger than the substrate inner diameter. The substrate is peeled off by pushing it out from the inner periphery with the center pin.

  However, there has been a problem that the intermediate layer may remain on the stamper after peeling, or the intermediate layer may be broken and broken.

  Therefore, as a method for easily peeling off the stamper by weakening the adhesion between the UV curable resin and the stamper, a method of providing a release layer on the stamper (Patent Document 1) or the material of the intermediate layer differs between the substrate side and the stamper side. Patent Document 2 discloses a method for weakening the adhesion of an ultraviolet curable resin that comes into contact with a stamper using an ultraviolet curable resin. Thus, the stamper peeling process is facilitated by weakening the adhesion between the ultraviolet curable resin and the stamper.

  In addition to the adhesiveness, where the peeling start position is is greatly affected on the peeling result. Bonding the substrate and stamper with UV curable resin When UV curable resin protrudes into the center hole of the stamper, depending on the cross-sectional shape of the protrusion, the peeling start position may be on the substrate side or on the stamper side, so the yield is high. There is a problem in forming the intermediate layer on the substrate.

  FIG. 9 prevents the ultraviolet curable resin 13 from protruding into the opening of the stamper when the stamper 14 and the substrate disclosed in Patent Document 3 are bonded together. In Patent Document 3, a protrusion preventing groove is provided outside the information recording layer of the substrate 61 on the opening side of the substrate 61 to prevent the ultraviolet curable resin 13 from protruding to the opening side of the stamper.

  Further, in Patent Document 4, as shown in FIG. 10, after the ultraviolet curable resin 13 is applied and spread on the substrate 11 on which the information recording layer 12 is formed, the substrate 11 and the stamper 14 are bonded together. Thereafter, the ultraviolet ray 75 is irradiated only in the vicinity of the center hole, thereby forming the cured ultraviolet ray curable resin 13 a on the inner periphery of the ultraviolet ray curable resin 13. After that, it is disclosed that the ultraviolet curable resin 13a prevents the ultraviolet curable resin 13 from diffusing in the inner peripheral direction and then irradiating the entire surface with ultraviolet rays to prevent the ultraviolet curable resin 13 from protruding in the inner peripheral direction.

When the techniques disclosed in Patent Documents 3 and 4 are used, the uncertainty of the peeling start point can be removed by preventing the ultraviolet curable resin from protruding.
Japanese Patent Laid-Open No. 06-060439 JP 2003-203402 A Japanese Patent Laid-Open No. 9-259466 JP 2000-123427 A

  When the method disclosed in Patent Documents 3 and 4 is used so that the UV curable resin does not protrude from the inner periphery, the adhesion between the UV curable resin and the stamper disclosed in Patent Documents 1 and 2 is weakened. Thus, it is easy to peel the ultraviolet curable resin from the stamper.

  However, in the method of providing the protrusion preventing groove on the inner periphery of the substrate shown in FIG. 9, since the ultraviolet curable resin moves so as to accumulate in the groove portion, the film thickness is reduced in the region near the groove and the flatness is maintained. Becomes difficult. Further, in the method of irradiating the ultraviolet curable resin in the vicinity of the center hole shown in FIG. 10 to prevent the protrusion, the ultraviolet ray is irradiated and the curing starts when the ultraviolet curable resin reaches the diffusion stop position to the inner periphery. However, the UV curable resin is not instantly cured, in other words, the viscosity increases. In other words, it is difficult to obtain an intermediate layer with a flat film thickness because the increase in viscosity slows the progress of the UV curable resin in the inner circumferential direction and causes a difference in the mobility of the UV curable resin with the non-UV irradiation region. May be. In both methods, the coating amount of the UV curable resin must be adjusted with high accuracy.

  On the other hand, when the ultraviolet curable resin is protruded, the above problems can be solved. However, in the actual manufacturing process, it is difficult to uniformly control the cross-sectional shape of the protrusion, and there is a problem that the peeling start position becomes unstable and as a result, the peeling surface cannot be stably determined.

  Accordingly, an object of the present invention is to improve the yield of the stamper without increasing the number of steps from bonding to separation of the substrate and the stamper while avoiding the above-mentioned problems associated with the step of stopping the diffusion of the UV curable resin on the inner periphery. It is to provide a method of peeling.

  In order to achieve the above object, according to the present invention, an information recording layer is formed on a substrate provided with guide grooves or information pits, and then an ultraviolet curable resin is applied to form a stamper having an inner diameter larger than the inner diameter of the substrate. And a step of curing with ultraviolet rays in a state where the ultraviolet curable resin protrudes from the center hole of the stamper, and the ultraviolet curable resin protruding from the central hole of the stamper is pushed up from the inner periphery while being pressed by a center pin and peeled off. To do.

  By applying the present invention, it is possible to efficiently improve the separation stability between the intermediate layer and the stamper without newly increasing the number of procedures compared to the conventional separation method when manufacturing an optical information recording medium. Therefore, it is possible to reduce the occurrence rate of defects in the intermediate layer forming step.

  Furthermore, the present invention is an effective means even when the multilayer structure of the optical information recording medium is formed in the reverse order.

  The inventor examined a method of bonding a resin substrate with an opening formed in the center and a stamper through a resin film, then curing the resin film, and then peeling the stamper with a high yield. It was found that the stamper can be peeled off at a high yield by peeling.

  In the present invention, a first substrate having an opening formed in the center and a second substrate are bonded together via a resin film. At this time, a substrate whose diameter of the opening of the first substrate for forming the resin film is smaller than the diameter of the opening of the second substrate to be bonded to the first substrate is used.

  The resin film formed on the first substrate is formed such that the position of the end portion on the opening side is larger than the diameter of the opening of the second substrate. Thereafter, the second substrate is bonded to the first substrate through a resin film. After the bonding, the resin film is bonded so that the end portion on the opening side of the first substrate is between the opening of the first substrate and the opening of the second substrate. As a result, the diameter of the end portion of the resin film on the opening side of the first substrate is larger than the diameter of the opening of the second substrate and smaller than the diameter of the opening of the first substrate. In a state where the bonding is completed, the resin is filled between the first substrate and the second substrate, and a resin film is formed on the side wall portion that forms the opening of the second substrate. It becomes the shape made.

  Next, the resin film is cured, and then the second substrate is peeled from the opening side. The separation of the second substrate is performed using a cylindrical jig that is larger than the diameter of the opening of the first substrate and smaller than the diameter of the opening of the second substrate. At this time, it is important that the diameter of the jig is larger than the diameter of the resin film on the opening end side of the first substrate. Since the diameter of the jig is larger than the diameter of the resin film on the opening end side of the first substrate, the outer periphery of the jig comes into contact with the resin film protruding from the second substrate.

  In this state, by pushing up the first substrate with the jig, the resin film can be pushed up on the surface of the jig, and the second substrate can be peeled off with a high yield.

In other words, the present invention
Forming a transparent resin film on a first substrate having an opening in the center, and bonding the first substrate to a second substrate having an opening in the center through the transparent resin film; A method for producing an optical information recording medium, comprising: a step of curing a transparent resin film; and a peeling step of peeling the second substrate from the transparent resin film,
The diameter of the opening of the first substrate is smaller than the diameter of the opening of the second substrate;
The inner peripheral side end of the first substrate of the transparent resin film formed in the step of forming the transparent resin film is larger than the diameter of the opening of the second substrate,
The diameter of the inner peripheral side end of the first substrate of the transparent resin film after the bonding step is finished is larger than the diameter of the opening of the second substrate, and smaller than the diameter of the opening of the first substrate,
An optical information recording medium characterized in that the peeling step is performed by pressing a transparent resin film protruding between the diameter of the first substrate and the diameter of the second substrate after fixing the second substrate. It is a manufacturing method.

  The first substrate and the second substrate are a resin substrate on which an information recording layer is formed, the second substrate is a combination of a transparent stamper, and the first substrate is a resin substrate. A combination of a glass substrate and a second substrate is conceivable. In the case of a glass substrate and a resin substrate, the information recording layer may or may not be formed on the resin substrate.

  Further, in the step of forming the transparent resin film, while rotating the first substrate at a low speed, the material for forming the transparent resin film is dropped at a position that becomes the inner peripheral edge of the transparent resin film, and then the first substrate is dropped. It is preferable to rotate the substrate at a high speed.

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

Example 1
The disk-shaped substrate 11 is a polycarbonate substrate having an outer diameter of 80 mm, an inner diameter of 15 mm, and a thickness of 1.1 mm, on which guide grooves or information pits are transferred on one surface by injection molding. The information recording layer 12 was formed by sputtering on the surface on which the guide groove or information pit was formed.

  Thereafter, the substrate 11 was rotated at 100 rpm while continuously dropping the UV curable resin 13 serving as an intermediate layer at a radius of 15 mm from the center of the substrate 11, and the donut-shaped UV curable resin 13 was applied on the substrate 11. . The applied ultraviolet curable resin 13 had a width of 6 mm in the radial direction. At that time, the inner peripheral radius was 12 mm. The ultraviolet curable resin 13 used here is KAYARAD KDL-118 (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYARAD KDL-118, viscosity 578 mPa · s).

  Thereafter, the substrate 11 was rotated at 1000 rpm for 4 seconds, and further rotated at 5000 rpm for 4 seconds to spread the ultraviolet curable resin 13 on the substrate 11 (see FIG. 1A).

  The rotation was divided into two stages. In order to uniformly and stably rotate at 5000 rpm for 4 seconds in the circumferential direction for controlling the film thickness, first, the ultraviolet curable resin 13 on the substrate 11 was applied by rotating at 1000 rpm for 4 seconds. This is because it was necessary to wet the entire surface on the outer peripheral side from the position. In this way, the film thickness distribution in the circumferential direction of the substrate can be kept small.

  The stamper 14 has an outer diameter of 86 mm, an inner diameter of 22 mm, and a thickness of 1.18 mm, and the inner diameter and the outer shape are larger than those of the substrate 11. As shown in FIG. 1B, the substrate 11 and the stamper 14 were bonded together. Bonding of the substrate 11 and the stamper 14 was performed in a vacuum so that air bubbles would not enter between them.

  By the bonding, the ultraviolet curable resin 13 moves in the inner circumferential direction and the outer circumferential direction due to the weight of the stamper 14 and capillary action. As a result, the stamper 14 spreads over the entire surface, and finally the ultraviolet curable resin 13 protrudes from the end of the bonded surface.

  Thereafter, in order to improve the flatness of the film thickness, the pressure was released to atmospheric pressure, and the ultraviolet curable resin 13 was cured by irradiating the ultraviolet rays 15 from the back surface of the stamper 14 (see FIG. 1C). At this time, the width (a) of the ultraviolet curable resin 13 spreading in the inner peripheral direction and protruding in the horizontal direction from the inner peripheral end of the stamper 14 with respect to the surface of the substrate 11 was 0.5 mm. The film thickness of the intermediate layer after curing was 15 μm ± 0.5 μm.

  The stamper 14 bonded to the substrate 11 was fixed to the fixing table 16 by vacuum suction. The center pin 17 has a cylindrical shape with an outer diameter of 21.5 mm, and the radius of curvature of the outer peripheral edge is 0.1 mm or less (see FIG. 2D).

  The center pin 17 was lifted on the same central axis as the substrate 11 and the stamper 14, and the substrate 11 was pushed upward to peel off the stamper 14. Since the distance between the center pin 17 and the inner peripheral side wall of the stamper 14 is 0.25 mm, the outer peripheral edge of the center pin 17 comes into contact with the ultraviolet curable resin 13 protruding 0.5 mm from the center hole of the stamper (FIG. 2E). reference). The substrate 11 could be pushed up while pressing the ultraviolet curable resin 13 protruding from the center pin 17, and the substrate 11 was pushed up and peeled off as it was (see FIG. 2 (f)). As a result, the UV curable resin 13 remained on the substrate 11 without breakage four times after five trials.

(Example 2)
About Example 2 shown below, since it is the same to the hardening process of the ultraviolet curable resin 13 demonstrated in Example 1 on the way, it abbreviate | omits. The subsequent steps are shown in FIG.

  The difference from the first embodiment is that the outer diameter of the center pin 27 is 21.5 mm in the first embodiment, which is 21.99 mm, which is almost the same as the inner diameter 22 mm of the stamper 14. Point (see FIG. 3A).

  The ultraviolet curable resin 13 adhering to the inner peripheral side wall of the stamper 14 is scraped off immediately before the center pin 27 rises and pushes up the substrate 11 (see FIG. 3B). Thereafter, the center pin 27 is further raised, and the stamper 14 is peeled off (see FIG. 3C).

  By adopting such a method, a peeling start position is directly created between the stamper 14 and the ultraviolet curable resin 13, so that the ultraviolet curable resin 13 does not remain on the stamper 14 side during peeling, and 5 of the five trials. In both cases, an intermediate layer could be formed on the substrate.

Creating a peeling start position directly between the stamper 14 and the UV curable resin 13 is
When a flat plate is peeled as in this case, it is generally considered that the resin peels off from the stamper at a certain point, and a region peeled off in the plane direction spreads from there. That is, it is considered that “the part where the end is peeled” = “peeling start position”. In this case, the “part where the end is peeled off” becomes important.

  In the case of peeling a material with a resin sandwiched between the substrate and the stamper, two types of the peeling start position can be considered: the inner peripheral end portion of the interface between the substrate and the resin, or the inner peripheral end portion of the interface between the stamper and the resin. . However, simply pulling in the direction of peeling the substrate and stamper does not tell from which interface the peeling starts. Therefore, in the second embodiment, the center pin 27 has a diameter substantially equal to the inner diameter of the stamper 14. For this reason, at the time of bonding, the resin extending to the wall surface of the opening of the stamper is peeled off while being pressed, and thereafter the resin is peeled off while being pressed.

  That is, stable peeling is enabled by two effects of “the resin on the stamper side wall is peeled off” + “the resin is peeled off while pressing the resin”.

(Example 3)
Example 3 shown below is almost the same as the process of Example 1, but the process of applying the ultraviolet curable resin 13 is different. In this embodiment, an ultraviolet curable resin 13 is applied to the substrate 11 at a radius of 11 mm from the center of the substrate 11 to form a donut shape having a width of 6 mm in the radial direction as in the first embodiment, and its inner peripheral radius is 8 mm. there were.

  Thereafter, the substrate 11 was rotated in the same manner as in Example 1 to spread the ultraviolet curable resin 13 (see FIG. 4A).

  As shown in FIG. 4B, the stamper 14 and the substrate 11 were bonded together in a vacuum. The ultraviolet curable resin 13 moves in the inner and outer circumferential directions by the weight of the stamper 14 and the capillary phenomenon. Since the 3 mm region inside the center hole of the stamper is wet at the stage of coating and spreading, it is easy for the UV curable resin 13 moved in the inner circumferential direction to move inward in the horizontal direction. Therefore, adhesion of the ultraviolet curable resin 13 to the side wall of the stamper 14 can be suppressed, and as a result, a chevron shape can be formed.

  Then, it hardens | cures with the ultraviolet-ray 15 (refer FIG.4 (c)).

  Next, the stamper 14 bonded to the substrate 11 was fixed to the fixing table 16 by vacuum suction. The center pin 17 has a cylindrical shape with an outer diameter of 21.5 mm, and the radius of curvature of the outer peripheral edge is 0.1 mm or less (see FIG. 5D).

  Next, the ultraviolet curable resin 13 protruding to the inner periphery is pushed up using the center pin 17 (see FIG. 5E), and the substrate 11 is peeled from the stamper 14 (see FIG. 5F). As a result of the above-described method, the intermediate layer could be formed on the substrate without breakage in 5 out of 5 trials.

  Further, since the ultraviolet curable resin 13 is not attached to the side wall of the stamper 14 from the beginning, it is possible to eliminate the possibility that the ultraviolet curable resin 13 is peeled off from the side wall of the stamper 14 in the peeling process and causes dust.

Example 4
In Examples 1 to 3, a production method for producing a multilayer optical recording medium while forming an ultraviolet curable resin as an intermediate layer on a substrate was described. In contrast, the present embodiment is a manufacturing method for manufacturing a multilayer optical recording medium while forming an intermediate layer on a glass stamper.

  Hereinafter, the manufacturing method of the present embodiment will be described with reference to the drawings.

  An ultraviolet curable resin 42 is applied in a donut shape on a glass substrate 41 having an inner diameter of 19 mm, an outer diameter of 80 mm, and a thickness of 1.2 mm at a radius of 15.5 mm from the center. The glass substrate 41 is rotated to rotate the ultraviolet curable resin 42 into glass. Spread on the substrate 41. A glass substrate 41 on which the ultraviolet curable resin 42 was spread and a glass stamper 43 having an inner diameter of 23 mm, an outer diameter of 80 mm, and a thickness of 1.2 mm were bonded together in a vacuum. After opening to the atmosphere, ultraviolet rays were irradiated from the back side of the glass stamper 43 to cure the ultraviolet curable resin 42. The film thickness of the cured ultraviolet curable resin 42 was 75 μm, and the width of the ultraviolet curable resin 42 protruding from the center hole of the glass stamper 43 in the horizontal direction of the glass substrate 41 was 0.5 mm.

  Thereafter, the back surface of the glass stamper 43 was fixed to the fixing table 44 by vacuum suction (see FIG. 6A). Next, the ultraviolet curable resin 42 which protruded to the inner peripheral side was pressed by the center pin 45 having an outer diameter of 22.5 mm and peeled from the glass stamper 43 (see FIG. 6B).

  Next, an information recording layer 46 was formed on the ultraviolet curable resin 42 by sputtering (not shown). Next, an ultraviolet curable resin 47 having a weaker adhesive strength than the ultraviolet curable resin 42 was applied and spread, and bonded to a glass stamper 48 having an inner diameter of 27 mm, an outer diameter of 80 mm, and a thickness of 1.2 mm in a vacuum. Thereafter, ultraviolet rays were irradiated from the back side of the glass stamper 48 to cure the ultraviolet curable resin 47 (not shown). Here, the film thickness of the ultraviolet curable resin 47 after curing was 25 μm, and the width of the ultraviolet curable resin 47 protruding in the horizontal direction of the glass substrate 41 from the center hole of the glass stamper 48 was 0.5 mm. The back surface of the glass stamper 48 is fixed to the fixing table 44 by vacuum suction, and an ultraviolet curable resin 47 protruding toward the inner peripheral side is pressed by a center pin 49 having an outer diameter of 26.5 mm (see FIG. 6C). It peeled from 48 (refer FIG.6 (d)).

  An information recording layer 50 was formed on the ultraviolet curable resin 47 by sputtering (not shown). Next, an ultraviolet curable resin 51 having a stronger adhesive strength than the ultraviolet curable resin 42 was applied and spread on a polycarbonate substrate 52 having an inner diameter of 15 mm, an outer diameter of 80 mm, and a thickness of 1.1 mm (not shown). Thereafter, the glass substrate 41 on which a plurality of recording layers were formed and the polycarbonate substrate 52 were bonded together in a vacuum via an ultraviolet resin.

  Thereafter, the ultraviolet curable resin 51 was cured by irradiating ultraviolet rays from the back surface of the polycarbonate substrate 52. At this time, the film thickness of the ultraviolet curable resin 51 existing between the information recording layer 50 and the polycarbonate substrate 52 is 10 μm, and the ultraviolet curable resin 51 protruding from the center hole of the glass substrate 41 in the horizontal direction of the polycarbonate substrate 52. The width was 0.5 mm (see FIG. 7 (e)).

  Next, the glass substrate 41 is fixed to the fixing table 44 by vacuum suction (see FIG. 7F), and the ultraviolet curable resin 51 protruding from the inner periphery is pushed up by the center pin 53 having an outer diameter of 18.5 mm to thereby raise the glass substrate 41. (See FIG. 7 (g)).

  By this step, the multilayer recording structure formed on the glass substrate 41 moved onto the polycarbonate substrate 52, and an optical information recording medium having two information recording layers was obtained.

  Examples 1 to 4 have all been described using an ultraviolet curable resin, but can also be implemented using a thermosetting resin.

(Comparative example)
As a comparison of Examples 1 to 4, the results when the present invention is not applied will be described. The process up to the bonding process between the substrate and the stamper is the same as that in the first embodiment, and is therefore omitted. The center pin 57 used in the peeling process shown in FIG. 8 has an outer diameter of 20 mm. At this time, the center pin 57 does not push the ultraviolet curable resin 13 protruding on the substrate 11. Therefore, after the peeling, the ultraviolet curable resin 13 remained on the substrate 11 without being damaged only once after five trials.

The figure explaining the process of Example 1 of this invention. The figure explaining the process of Example 1 of this invention. The figure explaining the process of Example 2 of this invention. The figure explaining the process of Example 3 of this invention. The figure explaining the process of Example 3 of this invention. The figure explaining the process of Example 4 of this invention. The figure explaining the process of Example 4 of this invention. The figure explaining the comparative example at the time of not using this invention. The figure explaining the prior art example which provided the protrusion prevention groove | channel on the board | substrate. The figure explaining the prior art example which hardens | cures an inner periphery vicinity previously with an ultraviolet-ray.

Explanation of symbols

11 Substrate 12 Information recording layer 13 UV curable resin 14 Stamper 15 UV 16 Fixing base 17 Center pin 27 Center pin 41 Glass substrate 42 UV curable resin 43 Glass stamper 44 Fixing base 45 Center pin 46 First information recording layer 47 UV curable resin 48 Glass stamper 49 Center pin 50 Second information recording layer 51 UV curable resin 52 Polycarbonate substrate 53 Center pin 57 Center pin 61 Substrate 61a Protrusion prevention groove 13a Cured UV curable resin 75 UV

Claims (4)

A step of forming a transparent resin film on a first substrate having an opening in the center, and the first substrate are bonded to a second substrate having an opening in the center through the transparent resin film A method for producing an optical information recording medium, comprising: a step; a step of curing the transparent resin film; and a peeling step of peeling the second substrate from the transparent resin film,
The diameter of the opening of the first substrate is smaller than the diameter of the opening of the second substrate;
The inner peripheral side end of the first substrate of the transparent resin film formed in the step of forming the transparent resin film is larger than the diameter of the opening of the second substrate,
The diameter of the inner peripheral side end of the first substrate of the transparent resin film after the bonding step is larger than the diameter of the opening of the second substrate, and the diameter of the opening of the first substrate. Smaller than
The peeling step is performed by pressing the transparent resin film protruding between the diameter of the first substrate and the diameter of the second substrate after fixing the second substrate. A method for manufacturing an optical information recording medium.   2. The method of manufacturing an information recording medium according to claim 1, wherein the first substrate is a resin substrate having an information recording layer, and the second substrate is a transparent stamper.   The method for manufacturing an information recording medium according to claim 1, wherein the first substrate is a resin substrate and the second substrate is a glass substrate.   In the step of forming the transparent resin film, while rotating the first substrate at a low speed, a material for forming the transparent resin film is dropped at a position to be an inner peripheral edge of the transparent resin film, and then the first substrate is dropped. 2. The method of manufacturing an optical information recording according to claim 1, wherein one substrate is rotated at a high speed.

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