JP2005149600A - Manufacturing method of optical recording medium sample, analyzing method of optical recording medium sample, and manufacturing apparatus of optical recording medium sample - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical recording medium sample by which a surface state of a substrate of the optical recording medium can be analyzed sufficiently, exactly, and accurately. <P>SOLUTION: The manufacturing method of the optical recording medium sample comprises a substrate dissolving process in which a contact plane for the substrate of a dielectric layer is exposed by dissolving the substrate using liquid which can dissolve selectively the substrate without dissolving the dielectric layer of the optical recording medium having the substrate and the dielectric layer formed at one side of the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical recording medium sample preparation method, an optical recording medium sample analysis method, and an optical recording medium sample preparation apparatus.

  In recent years, optical recording media such as optical discs such as CD, CD-R, CD-RW, and DVD have become more complicated and finer in order to realize larger capacity or rewritable optical recording media. Those having a structure have been developed. Specifically, a so-called Blu-ray disc or the like has been studied as a large-capacity optical recording medium (see Non-Patent Documents 1 to 3). Since such an optical recording medium is required to have a higher level of manufacturing technology because of the complexity and fineness of its structure, in order to maintain the product yield equal to or higher than that of conventional optical recording media. The quality control is an important factor than ever.

  This optical recording medium usually has a structure in which a recording layer, a reflective layer, etc. are laminated on a substrate, but the surface shape on the laminated side of the substrate affects the characteristics of the optical disc. Therefore, there is a demand for a method of analyzing with high accuracy and excellent accuracy.

In a method known as a method for analyzing the surface of the laminated side of such a substrate, usually, each layer laminated on the substrate is first peeled off in order from the top layer with an adhesive tape, dissolved with an acid or under reduced pressure. The surface of the substrate is finally exposed by removing it using means such as etching with high-speed charged particles such as sputtered particles. Then, the surface shape of the exposed substrate is observed, the layer structure is analyzed, or the recording mark is measured.
Nikkei Electronics, Nikkei BP, March 31, 2003, pages 135-150 Nikkei Electronics, Nikkei BP, May 12, 2003, pp. 119-133 Nikkei Electronics, Nikkei BP, June 9, 2003, pp. 57-64

  However, the present inventors have examined the above-described conventional analysis method in detail. When the analysis method is used, the dielectric layer or the surface of the substrate on the laminated side is obtained even after the removal process of each layer. It became clear that the recording layer remained. In this way, when analysis such as observation of the substrate surface is performed with each layer remaining on the substrate surface, for example, the state of the groove or land formed on the substrate or the surface roughness of the substrate can be accurately grasped. It becomes difficult and the analysis accuracy decreases.

  Accordingly, the present invention has been made in view of the above circumstances, and an optical recording medium sample preparation method, an optical recording medium sample analysis method, and an optical recording medium sample analysis method capable of sufficiently accurately and accurately analyzing the surface state of the substrate of the optical recording medium, and An object of the present invention is to provide an optical recording medium sample manufacturing apparatus.

  As a result of intensive studies to achieve the above object, the present inventors have found that the surface state can be grasped without directly analyzing the laminated side surface of the substrate of the optical recording medium, and the present invention is completed. It came to.

  That is, the optical recording medium sample manufacturing method of the present invention can selectively dissolve the substrate without dissolving the dielectric layer of the optical recording medium having the substrate and the dielectric layer formed on one side of the substrate. And a substrate dissolving step of exposing the contact surface of the dielectric layer with the substrate by dissolving the substrate using a liquid. Although the reason why such a method for producing an optical recording medium sample can achieve the above-mentioned problem has not been clarified at present, the present inventors consider the following as one of the factors. However, the factor is not limited to this.

  Optical recording media such as phase change optical disks or magneto-optical disks that have been developed in recent years, especially dielectric layers that are difficult to completely dissolve even with very strong acids such as hydrofluoric acid, etc. The functional layer is provided. In order to directly analyze the laminated surface of the substrate of the optical recording medium provided with such a dielectric layer, it is necessary to completely expose the portion to be analyzed of the surface of the substrate.

  However, if the dielectric layer provided on the surface of the substrate is removed by a conventional method, it is difficult to completely dissolve and remove the dielectric layer even if a strong acid is used. Since it is difficult to remove even by removal or etching, a part thereof remains on the portion of the substrate surface to be analyzed. The groove or roughness of the substrate surface has irregularities on the order of several nm to several μm, and even if a slight dielectric layer remains on the substrate surface, the surface condition is analyzed sufficiently accurately and accurately. It is thought that it cannot be done.

  On the other hand, when the method for producing an optical recording medium sample of the present invention is used, the obtained optical recording medium sample is in a state where the contact surface of the dielectric layer with the substrate is exposed. The substrate of the optical recording medium needs to transmit light for reproduction or light for recording, and the constituent material of such a substrate is a material that can be easily dissolved and removed as compared with the material used for the dielectric layer. The constituent material of the substrate does not remain in the portion to be analyzed of the contact surface of the dielectric layer with the substrate.

  In addition, the present inventors have transferred the profile of the surface of the dielectric layer on the dielectric layer side of the substrate, such as grooves, lands, or surface roughness, with sufficient accuracy and accuracy. I found out. Thus, the state of the substrate surface can be effectively grasped by analyzing the surface of the dielectric layer without directly analyzing the shape of the substrate surface.

  Further, in the conventional method for producing an optical recording medium sample, it is necessary to remove a plurality of layers formed on a substrate. Furthermore, it is necessary for each of these layers to adopt a removal means suitable for the material constituting the layer, and even if the same removal means is used, the conditions of the apparatus used for the means or the type of liquid used for the method, etc. It was necessary to change appropriately.

  On the other hand, in the method for producing an optical recording medium sample of the present invention, since only the substrate has to be removed, time, labor and cost tend to be reduced as compared with the conventional method.

  In the method for producing an optical recording medium sample of the present invention, the substrate dissolving step is preferably a step of exposing a contact surface of the dielectric layer with the substrate by dissolving a part of the substrate using a liquid. By dissolving only a part of the substrate in this way, the obtained optical recording medium sample tends to be difficult to bend or become flexible. Therefore, the dielectric layer provided in the obtained optical recording medium sample There is a tendency that the shape of the contact surface can be analyzed more accurately and accurately.

  Also, the method for producing an optical recording medium sample of the present invention is a step of exposing the contact surface of the dielectric layer with the substrate by dripping a liquid from the opposite side of the substrate to dissolve the substrate. preferable. Such a dropping method can simplify the apparatus configuration and the manufacturing operation, and has a low possibility of damaging the optical recording medium, and thus tends to obtain an optical recording medium sample efficiently.

  Furthermore, this optical recording medium sample preparation method is an optical recording method in which an optical recording medium is disposed in a state where the surface of the substrate opposite to the one side is inclined at a predetermined angle with respect to the horizontal direction before the substrate melting step. More preferably, it includes a medium placement step. By using such a method, both the dropped liquid and the substrate material dissolved by the liquid flow down from the optical recording medium sample, so there is no need to provide a process for removing them again from the sample, and optical recording can be performed quickly. There is a tendency to be able to analyze media samples.

Further, in the above method for preparing an optical recording medium sample, a liquid in which the substrate is made of polycarbonate resin, the dielectric layer is made of dielectric oxide or dielectric nitride, and the liquid is mainly composed of a polar solvent. Is more preferable. By making the combination of the liquid, substrate constituent material and dielectric layer constituent material as described above, an optical recording medium sample can be obtained more easily, which can further reduce time, labor and cost. It tends to be. From such a viewpoint, the dielectric layer is made of a material selected from the group consisting of ZnS—SiO ₂ , SiCO, CeO ₂ , SiN or AlN, and the liquid is selected from the group consisting of chloroform, dichloromethane, THF, acetone or methyl ethyl ketone. It is more preferable that the liquid contains the selected organic solvent as a main component. It is also preferable to use a so-called chlorinated solvent such as chloroform or dichloromethane as the liquid.

  The method for analyzing an optical recording medium sample of the present invention can selectively dissolve a substrate without dissolving the dielectric layer of the optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate. By dissolving the substrate using a liquid, the contact surface of the dielectric layer with the substrate is exposed, and the contact surface is analyzed. As a result, it is possible to grasp the shape such as the groove, land, or surface roughness on the substrate surface sufficiently accurately and accurately. Therefore, by using the result obtained by this analysis method, it is possible to manufacture an optical recording medium with a higher yield.

  The method for producing an optical recording medium of the present invention is a method using the above-described analysis method in a quality control process. Accordingly, since the correlation between the manufacturing conditions and the state of the substrate surface can be compared and examined in more detail as compared with the conventional manufacturing method, the yield of the optical recording medium product can be improved. In the optical recording medium manufacturing method of the present invention, the manufacturing conditions of the optical recording medium can be adjusted based on the analysis result of the quality control process.

  Also, the optical recording medium sample preparation apparatus of the present invention selectively dissolves a substrate without dissolving the dielectric layer of the optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate. A drip member for dripping possible liquid, and a medium holding member for holding an optical recording medium so that the liquid dripped from the drip member is in contact with the surface opposite to the one side of the substrate. And Such an optical recording medium sample preparation apparatus can effectively realize the optical recording medium sample preparation method and the sample analysis method described above. Further, it is preferable that the medium holding member of the manufacturing apparatus holds the optical recording medium in a state where the surface of the substrate is inclined with respect to the horizontal direction because the manufacturing time of the optical recording medium sample tends to be further shortened.

  According to the present invention, there are provided an optical recording medium sample preparation method, an optical recording medium sample analysis method, and an optical recording medium sample preparation apparatus capable of sufficiently accurately and accurately analyzing the surface state of the substrate of the optical recording medium. be able to. Also, the method for producing an optical recording medium of the present invention can sufficiently improve the yield of the optical recording medium product as compared with the conventional method.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary, but the present invention is not limited to the following embodiments. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  First, an optical recording medium according to the method for producing an optical recording medium sample of this embodiment will be described. The optical recording medium used in the method for producing the optical recording medium sample of the present embodiment is not particularly limited. FIG. 1 is a partially cutaway perspective view showing an example of an optical disc (DVD-RW) as the optical recording medium. FIG. 2 is an enlarged perspective view of a partial region represented by R in the cross section of the optical disc 1 that is the DVD-RW shown in FIG.

  As shown in FIG. 2, the optical disc 1 shown in FIG. 1 is configured by laminating a disc 20 used for recording and a dummy substrate 30 via an adhesive layer 40 made of an adhesive. The disk 20 includes a substrate 22, a protective layer 28, a recording layer 24 disposed between the substrate 22 and the protective layer 28, a reflective layer 26 disposed between the protective layer 28 and the recording layer 24, and the substrate. 22 and a dielectric layer 23 disposed between the recording layer 24 and the recording layer 24. In other words, the dielectric layer 23, the recording layer 24, the reflective layer 26, and the protective layer 28 are laminated on the substrate 22 in this order from the substrate 22 side.

  The constituent material of the substrate 22 is not particularly limited as long as it is a material that supports each of the above layers and can transmit recording light and reproducing light. As such a constituent material, for example, glass or resin can be used. Of these, a resin is preferably used from the viewpoint of ease of molding.

  Examples of such a resin include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, polyethylene resin, polypropylene resin, and urethane resin. Among these, polycarbonate resins are preferably used from the viewpoints of processability and optical characteristics.

  Grooves (concave portions) 11 and lands (convex portions) 12 for tracking information necessary for recording information are formed on the surface of the substrate 22 on which the recording layer 24 is formed. The shape of the structure, the depth of the groove, and the track pitch are optimized in consideration of the overall signal quality including recording / reproducing characteristics and servo signal characteristics.

The dielectric layer 23 is a layer for protecting the recording layer 24 from causes of deterioration such as corrosion. As a constituent material of the dielectric layer 23, a dielectric oxide such as ZnS—SiO ₂ , SiCO or CeO ₂ or a dielectric material containing oxygen, or a dielectric nitride such as SiN or AlN is used. From the viewpoint of obtaining good waterproof properties or an appropriate refractive index, ZnS—SiO ₂ is preferably used. The dielectric layer 23 may be a plurality of layers made of different constituent materials, or may be a plurality of layers having the same constituent material and different composition ratios.

  Next, an optical recording medium sample manufacturing apparatus (hereinafter, referred to as “manufacturing apparatus” in some cases) used in the optical recording medium sample manufacturing method of the present embodiment will be described. FIG. 3 is a schematic perspective view of the manufacturing apparatus. The manufacturing apparatus 50 includes a dropping member 60 and a medium holding member 70 as main components.

  The dropping member 60 includes a container part 62, a nozzle part 64, and a valve part 66. The container part 62 is for storing therein a liquid that can selectively dissolve the substrate 22 without dissolving the dielectric layer 23 of the optical disk 1. The nozzle portion 64 forms an opening, but communicates with the container portion 62 and is provided to play the role of dripping the liquid delivered from the container portion 62 from the opening. . Further, the valve portion 66 is provided between the container portion 62 and the nozzle portion 64. By opening and closing the valve portion 66, the dropping of the liquid can be started and stopped. It also plays a role of adjusting the dropping speed.

  The dropping member 60 drops the liquid onto the optical disk 1 held by the medium holding member 70 described later, and therefore it is necessary to position the nozzle portion 64 above the optical disk 1. Accordingly, the nozzle portion 64 is usually held by the stand 80 or the like so that it can be arranged above the optical disc 1.

  The medium holding member 70 includes a support base 72, a shaft 74, and a liquid recovery unit 76. The support base 72 is provided to support the exposed surface 3 of the optical disc 1 in a state where it is inclined at a predetermined angle with respect to the horizontal direction (hereinafter referred to as “inclined state”). The shaft 74 is provided so as to extend upward from the upper surface of the support base 72. The shaft 74 is passed through the central opening of the optical disk 1 so that the optical disk 1 placed on the support base 72 in an inclined state does not slide down on the upper surface of the support base 72. Further, the liquid recovery unit 76 is provided for recovering the liquid dropped from the dropping member 60 and the lysate of the liquid. Therefore, a gap is provided between the outer peripheral surface of the support base 72 and the inner peripheral surface of the liquid recovery unit 76 so that the liquid or the like can be recovered.

  The dropping member 60 and the medium holding member 70 are arranged so that the liquid dropped from the dropping member 60 flows down from the periphery of the central opening of the optical disc 1 toward the outside in the radial direction. By being arranged in this way, grooves 11 and lands 12 in each area from the lead-in area (tracking area) through the recording area (data area) to the lead-out area formed on the substrate 22 of the optical disc 1. Alternatively, information on the surface condition such as surface roughness tends to be obtained at a time. From such a viewpoint, the drip member 60 and the medium holding member 70 may be arranged so that the liquid from the drip member 60 is dropped onto the outer peripheral end portion at the highest position of the inclined optical disc 1. . In this case, information on the state of each area from the lead-out area to the lead-in area formed on the substrate 22 of the optical disc 1 tends to be obtained. FIG. 3 shows a state in which the optical disc 1 is disposed on the medium holding member 70 and a liquid is injected into the dropping member 60.

  Next, a method for producing the optical recording medium sample of this embodiment will be described. The optical recording medium sample manufacturing method of the present embodiment is performed as follows using the manufacturing apparatus 50 described above, for example.

  First, the optical disc 1 is prepared. The optical disk 1 is a DVD-RW in this embodiment, but is a read-only optical disk such as a CD or DVD, a write-once optical disk such as a CD-R or DVD-R, another rewritable optical disk such as a CD-RW, or It may be a high-density recording optical disk such as Blu-ray, or a magneto-optical disk.

  Subsequently, the prepared optical disk 1 is placed on the support 72 by passing the shaft 74 through the central opening thereof on the support base 72 with the substrate 22 facing upward (on the nozzle part 64 side of the dropping member 60). Set (optical disc installation process). At this time, since the upper surface of the support base 72 is inclined at a predetermined angle with respect to the horizontal direction, the set optical disc 1 is also inclined.

  The predetermined inclination angle is determined by the flow-down condition of the liquid after the liquid described later is dropped onto the optical disc 1 and the material of the substrate 22 dissolved by the liquid (hereinafter referred to as “substrate material”). In order to adjust the flow drop state, it may be changed as appropriate. That is, when the flow-down condition is excessively fast, the amount of the dissolved substrate material with respect to the amount of the dropped liquid tends to decrease, that is, the dissolution efficiency of the substrate material tends to decrease. Further, if the flow-down state is excessively slow, it tends to take too much time and tends to dissolve up to a portion where the dissolution of the substrate 22 is not desired. The adjustment of the tilt angle may be performed before the substrate melting step described later, or may be performed during the substrate melting step. The inclination angle may be adjusted by appropriately selecting and exchanging a plurality of medium holding members 70 having different upper surface inclination angles. The medium holding member 70 has a mechanism for adjusting the upper surface inclination angle in advance. This mechanism may be used.

Next, an appropriate amount of liquid is injected into the container portion 62 of the dropping member 60 to prepare (liquid preparation step). As this liquid, a liquid that can dissolve the substrate 22 of the optical disc 1 but does not dissolve the dielectric layer 23 of the optical disc 1 is selected. For example, the material of the substrate 22 is polycarbonate resin, when those components of the dielectric layer 23 is added oxygen getter for preventing the free oxygen in the SiO _2, such as ZnS-SiO _2, dissolve the polycarbonate resin Preferred alcohols, fluorine alcohols, petroleum solvents or organic solvents other than cellosolve, such as chloroform, THF, acetone or MEK.

  Among these, it is more preferable to use a chlorinated solvent (chloroform, dichloromethane, etc.) excluding carbon tetrachloride. Such a chlorinated solvent tends to dissolve the polycarbonate resin relatively quickly and further suppress the destruction of the surface shape of the dielectric layer 23.

  The factor that tends to further suppress the destruction of the surface shape of the dielectric layer 23 using such a liquid has not been clarified in detail at present, but the present inventors One is considered as follows. When a resin material such as polycarbonate resin is used as the material of the substrate 22, if a liquid that dissolves the resin relatively slowly is selected, the liquid is considered to dissolve and swell the resin of the substrate 22. In some cases, it is considered that the dielectric layer 23 is destroyed due to the swelling of the resin. On the other hand, when a liquid that dissolves the resin material of the substrate 22 relatively quickly is used, it is difficult for the resin to swell, and it is considered that the surface shape of the dielectric layer tends to be further prevented from being destroyed. However, the factor is not limited to this.

  Next, the liquid described above is dropped from the nozzle portion 64 of the dropping member 60 toward the substrate 22 of the optical disc 1, and the substrate 22 is dissolved to expose the contact surface of the dielectric layer 23 with the substrate 22 (substrate dissolution). Process). The dropping speed of the liquid at this time can be appropriately adjusted by using the valve portion 66 according to the substrate melting efficiency, time, and the portion desired to be dissolved, and the inclination angle of the upper surface of the medium holding member 70 described above can be adjusted. You may carry out with adjustment. Note that when the dropping speed increases, the liquid flows down, but in this specification, it is assumed that the liquid is “dropped” even in that case.

  Further, the position on the optical disc 1 where the liquid is dropped (hereinafter referred to as “dropping position”) is not particularly limited as long as it can dissolve the substrate 22 of the optical disc 1, but is dropped from the dropping member 60. The liquid is preferably dropped around the central opening of the optical disc 1. Since the liquid dropped around the central opening flows down radially outward from the central opening, portions corresponding to the respective areas from the lead-in area of the substrate 22 through the recording area to the lead-out area are formed. There is a tendency to dissolve at once. Thereby, it exists in the tendency which can obtain the information of the surface state of the board | substrate of those area | regions at once.

  From the same point of view, it is preferable that the liquid from the dropping member 60 is dropped on the outer peripheral end portion at the highest position of the optical disc 1 in the inclined state. The liquid dropped on this portion tends to dissolve the portion of the substrate 22 corresponding to each region from the lead-out region around the outer peripheral end portion to the lead-in region through the recording region at a time. .

  Further, in this substrate dissolving step, it is preferable to drop the liquid so that only a part of the substrate 22 is dissolved. When all the substrates 22 are melted, the time required for the substrate melting process tends to be longer. In addition, since the optical recording medium sample obtained by completely dissolving and removing the substrate is flexible and easily changes in shape, it tends to be difficult to handle, and the surface shape of the dielectric layer 23 is analyzed. It tends not to be suitable. From such a viewpoint and the viewpoint of obtaining necessary information, it is more preferable to drop the liquid so as to dissolve a portion not exceeding 1/3 of the substrate area. However, depending on conditions such as a sample holding method, the substrate may be dissolved beyond this area.

  In addition, when the liquid is dropped, it is preferable to perform the substrate melting step while keeping the dropping position at substantially the same position. Thereby, it exists in the tendency which can omit the effort of a board | substrate melt | dissolution process more. Moreover, when the optical disc 1 is tilted, if the dropping position is dropped around the central opening of the optical disc or substantially the same position at the outer peripheral end portion at the highest position described above, particularly necessary information can be obtained while omitting trouble. This is more preferable.

  Further, as described above, when the optical disk 1 is tilted and the liquid dropping position is set to substantially the same position in the periphery of the central opening of the optical disk 1 or the outermost end at the highest position, only a small part of the substrate 22 in the radial direction It tends to be able to selectively dissolve only this region. Accordingly, particularly necessary information can be obtained while saving time and the surface shape of the dielectric layer 23 tends to be maintained, which is particularly preferable.

  If necessary, the optical disk 1 from which the substrate 22 has been dissolved and removed is washed with ethanol or the like to obtain an optical disk sample as an optical recording medium sample.

  According to the method for producing an optical recording medium sample of the present embodiment described above, the surface state of the substrate 22 of the optical disk 1 is sufficiently determined by various analyzes performed later, even though the substrate 22 is raised for eight days or more. Analyzes accurately and accurately. Although the factor is not clarified at present, the present inventors consider the following as one of the factors. However, the factor is not limited to this.

  That is, in the optical disc 1 as described above, in order to directly analyze the surface of the substrate 22 on the dielectric layer 23 side, it is necessary to completely expose the portion of the substrate 22 to be analyzed. However, if the dielectric layer 23 provided on the surface of the substrate 22 is to be removed by a conventional method, it is difficult to completely dissolve and remove the dielectric layer 23 using a strong acid. Since it is difficult to remove even by peeling or etching used, a part thereof remains on the surface of the substrate 22 to be analyzed. Grooves, lands, or roughness on the surface of the substrate 22 form irregularities on the order of several nanometers to several micrometers, and if the dielectric layer 23 remains on the surface of the substrate 22, the surface state is sufficient. It is considered that the analysis cannot be performed accurately and accurately.

  On the other hand, when the method for producing an optical recording medium sample of this embodiment is used, the obtained optical disk sample is in a state where the contact surface of the dielectric layer 23 with the substrate 22 is exposed. The substrate 22 of the optical disc 1 needs to transmit light for reproduction or light for recording, and the constituent material of such a substrate 22 is a material that can be easily dissolved and removed as compared with the material used for the dielectric layer 23. Therefore, the substrate material does not remain in the portion to be analyzed of the contact surface of the dielectric layer 23 with the substrate 22.

  In addition, it has been found that the contact surface of the dielectric layer 23 with the substrate 22 transfers a profile such as a groove, land or surface roughness on the dielectric layer side surface of the substrate 22 with sufficient accuracy and accuracy. did. As a result, the state of the surface of the substrate 22 can be effectively grasped by analyzing the surface of the dielectric layer 23 without directly analyzing the shape of the surface of the substrate 22.

  Further, in the conventional method for producing an optical recording medium sample, it is necessary to remove a plurality of layers including the dielectric layer 23 formed on the substrate 22. Furthermore, it is necessary for each of these layers to adopt a removal means suitable for the material constituting the layer, and even if the same removal means is used, the conditions of the apparatus used for the means or the type of liquid used for the method, etc. It was necessary to change appropriately. Furthermore, a layer using a material that is relatively difficult to dissolve, such as the dielectric layer 23, cannot be dissolved unless a strong acid such as hydrofluoric acid is used.

  On the other hand, in the method for producing an optical recording medium sample of the present invention, since only the substrate 22 has to be removed, there is a tendency that time, labor and cost can be reduced as compared with the conventional method. Furthermore, since the constituent material of the substrate 22 is easier to dissolve and remove than the dielectric layer 23 and the like, the handling of the liquid does not require as much care as the conventional method.

  In the present embodiment, the constituent material of the substrate 22 of the optical disk 1 is polycarbonate resin, and the optical disk 1 includes the dielectric layer 23. The method for producing the optical recording medium sample of the present invention is based on this combination. It is not limited to. For example, even if the optical disk 1 is a material other than polycarbonate resin as a constituent material of the substrate 22 and includes a functional layer made of a material other than a dielectric instead of the dielectric layer 23, such a functional layer is used. By selecting a solvent (liquid) that can selectively dissolve the substrate 22 without dissolving the substrate 22, the method for producing an optical recording medium sample of the present invention can be performed.

  Examples of such an optical disk 1 include a Blu-ray disk that is being studied as an optical recording medium for high-density recording. Among the Blu-ray discs, the write-once Blu-ray disc medium uses, for example, amorphous polyolefin, polylactic acid acrylic, etc. as a constituent material of the substrate 22 in addition to the polycarbonate resin. As the functional layer, for example, a recording layer such as an Ag—In—Sb—Te—Ge film, a Tb—Sb—Te—Ge film, or a Te—O—Pb film, or a reflective layer such as an Ag alloy is used. Is provided. In order to observe the recording layer surface of a write-once Blu-ray disc medium sample using polylactic acid acrylic as a constituent material of the substrate 22 and having a recording layer which is an Ag-In-Sb-Te-Be-based film as a functional layer For example, an optical recording medium sample can be obtained by dissolving the substrate using an alkaline solution such as an aqueous sodium hydroxide solution to expose the surface of the recording layer.

  Next, a method for analyzing the optical recording medium of this embodiment will be described. In this analysis method, after the above-described optical disc sample is prepared, the obtained optical disc sample is subjected to atomic force microscopy (AFM) and / or scanning electron microscopy (SEM). (Analysis process) is performed using the method.

  In the AFM method, the contact surface (exposed surface) of the optical disk sample obtained by the above production method with the exposed substrate 22 of the dielectric layer 23 is directly observed using a conventional atomic force microscope (AFM). This AFM method has a three-dimensional atomic resolution in the vertical direction and in-plane direction of the surface of the dielectric layer 23 to be observed, and a relatively high surface of an insulator, particularly an oxidized surface of the surface. Since it can be observed with resolution, it is possible to obtain information on the surface shape of the dielectric layer 23 with accuracy in the order of nm.

  In the SEM method, a conductive material such as a metal is provided on the exposed surface of the dielectric layer 23 of the optical disk sample obtained by the above-described production method by a method such as vapor deposition as necessary, and then a conventional scanning electron microscope ( Observation using SEM. When this SEM method is used, the surface shape of the dielectric layer 23 can be observed three-dimensionally relatively easily, and the surface shape of higher order (μm to mm order) than the above-described AFM method is also observed. be able to. In some cases, even if a conductor is not provided on the exposed surface of the dielectric layer 23, the electron beam is irradiated with a relatively low acceleration voltage or a current as small as possible is used. The exposed surface can be observed.

  By using these AFM method and SEM method in combination, information on the surface shape of the dielectric layer 23 in a wider range can be obtained. When the surface shape is evaluated by combining the AFM method and the SEM method, for example, a standard sample having a fine shape with clear dimensions and dimensional tolerances is observed by the AFM method and the SEM method, respectively, and the size of the fine shape is measured. By comparing the results, it is possible to cancel measurement errors resulting from differences in measurement methods. As the standard sample, for example, a standard sample for an AFM apparatus in which a rectangular pattern is formed on a Si substrate by a photolithography technique can be used.

  The optical recording medium sample manufacturing apparatus, the optical recording medium sample manufacturing method, and the optical recording medium sample analysis method of the present embodiment have been described above. The optical recording medium sample manufacturing apparatus of the present invention, the optical recording medium sample The production method and the analysis method of the optical recording medium sample are not limited to these.

  For example, in another method of manufacturing an optical recording medium sample according to another embodiment, a liquid that can selectively dissolve the substrate without dissolving the dielectric of the optical recording medium is sprayed and sprayed onto the optical recording medium to It may be dissolved. In this manufacturing method, a conventional liquid ejecting apparatus such as a dispenser can be used as an optical recording medium sample manufacturing apparatus or as a member included in the manufacturing apparatus. In this case, the substrate can be dissolved even if the surface of the optical recording medium on which the liquid is sprayed is arranged so as to be parallel to the vertical direction, or even if the surface is arranged in the direction of gravity. .

  In a method for preparing an optical recording medium sample according to another embodiment, when a hard coat is applied on the surface opposite to the dielectric layer side of the substrate, the hard coat portion is removed by polishing with a paper file. After that, it is also possible to bring the liquid into contact with the substrate.

  Further, in the method for analyzing an optical recording medium sample according to another embodiment, a solid surface shape observation method other than the AFM method and SEM method described above, for example, a normal optical microscope observation method, a laser microscope observation method, a transmission electron microscope ( (TEM) observation method or energy dispersive spectroscopy (EDS) can also be used.

  Furthermore, in the method for analyzing an optical recording medium sample according to another embodiment, an analysis means that is normally performed under atmospheric pressure conditions such as Fourier transform infrared spectroscopy (FT-IR) or Raman spectroscopy may be used. Analytical means usually performed under reduced pressure conditions such as electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) may be used. By using these analysis means, it is possible to obtain information on the chemical composition near the exposed surface of the dielectric layer.

  Information on the solid structure of the dielectric layer can be obtained by X-ray diffraction (XRD), and information on the composition of the dielectric layer can be obtained by fluorescent X-ray analysis (XRF). Furthermore, information on the bonding state of atoms on the exposed surface of the dielectric layer can be obtained by X-ray photoelectron spectroscopy (XPS) or ultraviolet photoelectron spectroscopy (UPS).

  Further, a sample is taken from the surface of the dielectric layer exposed by the above production method, and the sample is extracted with an acid, alkali or organic solvent, or the dielectric material is directly extracted from the surface, and the resulting extract is obtained. Can also be analyzed using analysis means using inductively coupled plasma (ICP), ion chromatography (IC), liquid chromatography (LC), gas chromatography (GC), or the like.

  Each analysis means mentioned above may be used individually by 1 type, or may be used in combination of 2 or more type. In addition, it is possible to obtain information on the chemical composition or the atomic bonding state in the thickness direction of the optical recording medium by combining with a sputtering method or the like. In this case, since the optical recording medium sample obtained by the manufacturing method of the present invention has removed the substrate that is an insulator from the beginning of analysis, even if AES or the like is used, the shift of the spectrum peak accompanying charging of the insulator, There is a tendency that the decrease in intensity or the occurrence of broadening or ghost peaks can be suppressed.

  Moreover, the various analysis methods and production apparatuses described above can be used in a method of manufacturing an optical disc. For example, after manufacturing a group (one lot) of optical disks, a part of the optical disks is arbitrarily extracted, and an optical disk sample is manufactured from the extracted optical disks using the above-described manufacturing apparatus. Then, by analyzing the optical disk sample, it is possible to determine whether the group of optical disks is not defective. In addition, a group of optical disks can be inspected by the above-described analysis method, optical disks determined to be defective can be removed, and only good optical disks can be sent to the next process. Further, it is possible to identify a problem in the manufacturing conditions of the optical disk determined to be a defective product, and to improve the manufacturing process of the optical disk based on this problem. Such an optical disk manufacturing method is an effective means for investigating the cause when a defective product is manufactured, and can contribute to maintaining a high yield of the optical disk product. Therefore, in the above-described optical disc manufacturing method, using the above-described manufacturing apparatus is an effective means for investigating the cause when a defective product is manufactured, and can contribute to maintaining a high yield of optical disc products. is there.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Analysis of DVD-RW substrate)
First, the surface shape of an ordinary polycarbonate resin substrate for DVD-RW (hereinafter referred to as “PC substrate”) was observed by the AFM method. An image of the observation result is shown in FIG. It was confirmed that the groove (black or a portion close thereto) and the land (white or a portion close thereto) formed a groove shape.

  In addition, the groove depth (groove depth) on the surface of the PC substrate was measured using the AFM method. FIG. 8 shows a profile showing the undulation state of the substrate surface obtained by setting the scanning direction of the AFM probe to the X direction in FIG. As a result, the groove depth was 36 nm. Further, the groove width (hereinafter referred to as “groove half-value width”) at an intermediate point in the depth direction of the groove was measured and found to be 225 nm.

(Production of DVD-RW)
Next, a DVD-RW disk medium (hereinafter referred to as “optical disk”) was obtained by a normal optical disk manufacturing method using a substrate similar to the PC substrate. That is, on the substrate, a dielectric layer 1 (thickness 72 nm) having ZnS—SiO ₂ (ZnS / SiO ₂ = 80/20, mass ratio) as a constituent material, ZnS—SiO ₂ (ZnS / SiO ₂ = 50). / 50, mass ratio) as a constituent material, dielectric layer 2 (thickness 5 nm), AGIST (Ag—Ge—In—Sb—Te) as a constituent material, recording layer (thickness 19 nm), ZnS—SiO ₂ A dielectric layer 3 (thickness: 21 nm) comprising (ZnS / SiO ₂ = 50/50, mass ratio) as a constituent material and a reflective layer (thickness: 140 nm) comprising Al—Cr as a constituent material are sequentially laminated, and further A dummy substrate (thickness: 0.6 mm) is formed on the adhesive layer on the top layer, and a top coat layer (spin coat method) is formed by using a UV curable resin blended with a polyfunctional acrylate such as DPHA. TC) To obtain an optical disk by Rukoto.

(Example 1)
First, the optical disk was placed on the support 72 of the medium holding member 70 in the optical recording medium sample manufacturing apparatus shown in FIG. 3 so that the substrate faces the dropping member 60 side. A separatory funnel was used as the dropping member.

  Next, an appropriate amount of chloroform was injected as a liquid into the container portion 62 of the dropping member 60 with the valve portion 66 closed.

  Subsequently, the valve portion 66 was opened so that the dropping speed was 1 to 4 drops / second, and dropping of chloroform toward the periphery of the central opening of the optical disk was started. During dropping of chloroform, the dropping position was not changed. During dropping, it was confirmed that the substrate was gradually dissolved from the dropping position of the optical disk toward the outside in the radial direction.

  And when the board | substrate melt | dissolved to the outer peripheral edge part of the optical disk, and the contact surface with the board | substrate of a dielectric material layer was exposed, dropping of chloroform was complete | finished and the optical disk sample of Example 1 was obtained.

  The contact surface (exposed surface) of the optical disk sample of Example 1 with the exposed substrate of the dielectric layer was observed using an AFM. An image of the observation result is shown in FIG. A convex region (white or a portion close to it), that is, a portion in contact with the groove of the substrate, and a concave region (black or a portion close to it), that is, a portion in contact with the land of the substrate were confirmed.

  In addition, when the height of the convex region of the exposed surface of the dielectric layer (hereinafter referred to as “convex region height”) was measured using the AFM method (profile is shown in FIG. 9), the value was measured. Was 39 nm. Further, the width of the convex region at the intermediate point in the height direction of the land (hereinafter referred to as “convex region half-value width”) was measured to be 228 nm. The height of the convex area in the dielectric layer corresponds to the depth of the concave area in the substrate, and the half width of the convex area in the dielectric layer corresponds to the half width of the concave area in the substrate.

(Comparative Example 1)
First, a cut was made in the adhesive layer of the optical disk using a cutter knife, and the dummy substrate was separated by peeling from the portion. Subsequently, an adhesive tape was applied to the surface exposed by peeling on the PC substrate side, and then the adhesive tape was pulled up to further peel off a part of the laminate to obtain an optical disk sample of Comparative Example 1. It was visually confirmed that the dielectric layer 3 and the recording layer remained on the surface exposed by the peeling.

  The surface exposed by peeling off the optical disk sample of Comparative Example 1 was observed using an SEM. An image of the observation result is shown in FIG.

  In addition, when the height of the convex region of the exposed surface of the optical disk sample was measured using the SEM method, the value was 22 nm. Moreover, it was 240 nm when the half value width of the convex area | region was measured.

(Comparative Example 2)
First, a cut was made in the adhesive layer of the optical disk using a cutter knife, and the dummy substrate was separated by peeling from the portion. Then, after sticking an adhesive tape on the surface exposed by peeling on the PC substrate side, a part of the laminate was further peeled by pulling up the adhesive tape. It was visually confirmed that the dielectric layer 3 and the recording layer remained on the surface exposed by the peeling.

  Next, hydrofluoric acid (content 22%) was dropped on the exposed surface after peeling with the adhesive tape to dissolve the dielectric layer 3, and nitric acid (6 N) was further dropped to dissolve the recording layer. Then, concentrated hydrofluoric acid was dropped again to dissolve the derivative layers 2 and 1 to obtain an optical disk sample of Comparative Example 2.

  The surface exposed by the above series of treatments of the optical disc sample of Comparative Example 2 was observed using AFM. An image of the observation result is shown in FIG. Although a portion close to white is observed in particular, it is assumed that this is due to the dielectric layer remaining on the substrate.

  In addition, when the height of the convex region of the exposed surface of the optical disk sample was measured using the AFM method (profile is shown in FIG. 10), the value was 39 nm. Moreover, it was 228 nm when the half value width of the convex area | region was measured.

(Example 2)
Using the method described in Example 1, quality control was performed in the manufacturing process of the DVD-RW substrate. 200 DVD-RWs (optical discs) were produced using the above-described normal DVD-RW manufacturing method, and these were made into a group (one lot). The target value (specification) of the convex region height of the optical disc was 40 nm, and the target value of the convex region half width was 230 nm.

  When the obtained optical disk sample for one lot was evaluated by the method described in Example 1, the 165 optical disks had a convex region height of 39 nm and a convex region half-value width of 229 nm, which were acceptable values. For the 35 optical disks, a part of the observation surface had a convex region height of 45 nm and a convex region half width of 250 nm.

  As a result of confirming the manufacturing conditions of these 35 optical disks, it became clear that there was a discharge abnormality around the position where these optical disks were placed in a sputtering apparatus for forming a dielectric thin film. After repairing this discharge abnormality, an optical disk for one lot was manufactured again and evaluated by the method described in Example 1. As a result, the height of the convex region of all 200 sheets was 39 nm and the half width of the convex region was 229 nm. An improvement in the retention was observed.

It is a partially cutaway perspective view showing an example of an optical disk used in the method for producing an optical recording medium sample of the present invention. FIG. 2 is an enlarged perspective view of a partial region represented by R in the cross section of the optical disc shown in FIG. 1. 1 is a schematic perspective view showing a preferred embodiment of an apparatus for producing an optical recording medium sample of the present invention. It is an AFM image of the substrate for DVD-RW. It is an AFM image of the optical disk sample which concerns on an Example. It is a SEM image of the optical disk sample concerning a comparative example. It is an AFM image of the optical disk sample which concerns on a comparative example. It is an AFM profile of a substrate for DVD-RW. It is an AFM profile of the optical disk sample which concerns on an Example. It is an AFM profile of the optical disk sample which concerns on a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 50 ... Production apparatus, 60 ... Dropping member, 62 ... Container part, 64 ... Nozzle part, 66 ... Valve part, 70 ... Medium holding member, 72 ... Support stand, 74 ... Shaft, 76 ... Liquid recovery part, 80 ... Stand.

Claims (11)

  By dissolving the substrate using a liquid capable of selectively dissolving the substrate without dissolving the dielectric layer of an optical recording medium having a substrate and a dielectric layer formed on one side of the substrate. A method for producing an optical recording medium sample, comprising: a substrate melting step of exposing a contact surface of the dielectric layer with the substrate.   2. The optical recording medium according to claim 1, wherein the substrate dissolving step is a step of exposing a contact surface of the dielectric layer with the substrate by dissolving a part of the substrate using the liquid. Sample preparation method.   The substrate dissolving step is a step of exposing the contact surface of the dielectric layer with the substrate by dripping the liquid from the opposite side of the substrate to dissolve the substrate. The method for producing an optical recording medium sample according to claim 1.   An optical recording medium disposing step of disposing the optical recording medium with the surface of the substrate opposite to the one side inclined at a predetermined angle with respect to a horizontal direction before the substrate melting step; A method for producing an optical recording medium sample according to claim 3. The substrate is composed of polycarbonate resin,
The dielectric layer comprises a dielectric oxide or a dielectric nitride as a constituent material,
The method for producing an optical recording medium sample according to any one of claims 1 to 4, wherein the liquid is a liquid containing a polar solvent as a main component. The substrate is composed of polycarbonate resin,
Said dielectric layer is a _ZnS-SiO 2, _SiCO, constitute a material selected from the group consisting of CeO 2, SiN or AlN material,
The optical recording medium according to claim 1, wherein the liquid is a liquid containing an organic solvent selected from the group consisting of chloroform, dichloromethane, THF, acetone, or methyl ethyl ketone as a main component. Sample preparation method. By dissolving the substrate using a liquid capable of selectively dissolving the substrate without dissolving the dielectric layer of an optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate. An analysis method for an optical recording medium sample, wherein the contact surface of the dielectric layer with the substrate is exposed and the contact surface is analyzed. A dropping member for dropping a liquid capable of selectively dissolving the substrate without dissolving the dielectric layer of an optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate;
An optical recording medium comprising: a medium holding member that holds the optical recording medium so that the liquid dropped from the dropping member contacts a surface of the substrate opposite to the one side. Sample preparation device. 8. The optical recording medium sample manufacturing apparatus according to claim 7, wherein the medium holding member holds the optical recording medium in a state where the surface of the substrate is inclined with respect to a horizontal direction. By dissolving the substrate using a liquid capable of selectively dissolving the substrate without dissolving the dielectric layer of an optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate. A method for producing an optical recording medium, comprising: a quality control step of exposing a contact surface of the dielectric layer with the substrate and analyzing the contact surface. By dissolving the substrate using a liquid capable of selectively dissolving the substrate without dissolving the dielectric layer of an optical recording medium comprising a substrate and a dielectric layer formed on one side of the substrate. A quality control step of exposing a contact surface of the dielectric layer with the substrate and analyzing the contact surface, and adjusting manufacturing conditions of the optical recording medium based on an analysis result of the quality control step, A method for manufacturing an optical recording medium.

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