JP2009163801A - Manufacturing system of glass substrate for magnetic disk, glass substrate for magnetic disk and magnetic disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To identify a step causing a surface defect of a glass substrate for a magnetic disk and to prevent further more generation of the surface defect by repairing the step. <P>SOLUTION: A manufacturing system 100 of the glass substrate for the magnetic disk includes storing means storing surface defect maps 120a to 120d typically showing the surface defect generated on the glass substrate when processing of each step is abnormal corresponding to one or more steps 103, 105, 106a and 106b for manufacturing the glass substrate 200 for the magnetic disk, a surface defect detecting device 130 detecting the surface defect 402 of the glass substrate 200 for the magnetic disk manufactured via each step, a recognition part 404 recognizing a surface defect map similar to the surface defect 402 and an informing part 406 informing a step matching the surface defect map recognized to be similar to the surface defect 402. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic disk glass substrate manufacturing system, a magnetic disk glass substrate, and a magnetic disk.

  In recent years, with the advancement of information technology, information recording technology, particularly magnetic recording technology, has made remarkable progress. As a substrate for magnetic recording media such as HDD (Hard Disk Drive), which is one of the magnetic recording media, a substrate replacing the aluminum substrate that has been widely used with the miniaturization, thinning, and high-density recording of magnetic disks. A glass substrate excellent in surface flatness and substrate strength has been used.

  As the magnetic recording technology increases in density, the magnetic head has been changed from a thin film head to a magnetoresistive head (MR head) and a giant magnetoresistive head (GMR head). The flying height from the center is narrowed to about 20 nm to 5 nm. A magnetic head equipped with such a magnetoresistive element may cause a head crash failure or a thermal asperity failure as an inherent failure.

  Thermal asperity failure means that the magnetoresistive element is heated by adiabatic compression or contact of air when the magnetic head passes over a minute convex or concave shape on the magnetic disk surface while flying. This is a failure that causes a read error. Therefore, for a magnetic head equipped with a magnetoresistive element, the magnetic disk surface is required to have extremely high smoothness and flatness. Also, if a magnetic layer is formed with dust or foreign matter attached to the substrate, convex portions will be formed on the outermost surface of the magnetic disk. Advanced cleaning techniques are required.

Under the circumstances as described above, the importance of the smoothness of the end face of the substrate has been recognized conventionally. As a method for inspecting the smoothness of a glass substrate, the surface of the glass substrate is irradiated with light using a device such as a surface defect detector (AOI: Automatic Optical Inspection) or OSA (Optical Surface Analyzer), and the intensity of reflected light. There is a method in which it is determined whether or not there are deposits, concave portions, and convex portions by displacement or the like (for example, Patent Document 1).
JP 2007-256133 A

  There must be a cause for the surface defect that occurs in the glass substrate, and it is often solved by finding and repairing the cause of the abnormal process. However, the repair of such a process is performed exclusively by the experience of skilled workers. Some skilled workers can sensuously determine what abnormality is caused by which process by simply looking at the distribution and type of detected surface defects. However, it is difficult for an inexperienced worker to identify the cause of surface defects.

  In view of such a problem, the present invention makes it possible to repair a glass disk on which a surface defect is found by identifying the process causing the abnormality and repairing the process. An object of the present invention is to provide a glass substrate manufacturing system, a magnetic disk glass substrate, and a magnetic disk.

  As a result of intensive studies on the above problems, the present inventors have found that regularity is observed in the surface defects generated in the glass substrate due to abnormalities in specific processes, and such typical surface defects are stored as a surface defect map. It is found that if a surface defect of a glass substrate to be inspected, which is detected using a surface defect device such as AOI, is collated, a process that causes the surface defect generated on the glass substrate can be identified. It came to be completed.

  In order to solve the above-described problems, a typical configuration of a magnetic disk glass substrate manufacturing system according to the present invention includes each process corresponding to one or more processes for manufacturing a magnetic disk glass substrate. A storage means for storing a surface defect map typically indicating a surface defect generated on the glass substrate when there is an abnormality in the processing of the substrate, and a surface defect of the glass substrate for magnetic disk manufactured through one or more steps is detected. It includes a surface defect detection means, a recognition means for recognizing a surface defect map similar to a surface defect, and a notification means for notifying a process corresponding to the surface defect map recognized to be similar to a surface defect. .

  According to said structure, the operator can prevent generation | occurrence | production of the surface defect beyond it by identifying the process causing the surface defect of a glass substrate, and repairing the said process.

  The notification means may notify the process corresponding to the same surface defect map only when the recognition means recognizes that any one of the same surface defect maps is similar to the surface defects of a predetermined number or more glass substrates. .

  This is because, when it is recognized that a specific surface defect map is similar to a plurality of surface defects, the reliability of the notification function is improved by notifying the process corresponding to the surface defect map for the first time.

  The above recognition means may recognize a similar surface defect map only when the number of individual defects included in the surface defect detected by the surface defect detection means is a predetermined number or more.

  This is because a glass substrate having a non-defective product level with the number of surface defects equal to or less than a predetermined number cannot be said to have an abnormality in the process, and a wasteful recognition process is omitted.

  In order to solve the above-described problems, the glass substrate for a magnetic disk according to the present invention is manufactured using any one of the above-described systems for manufacturing a glass substrate for a magnetic disk.

  In order to solve the above-mentioned problems, a magnetic disk according to the present invention is characterized in that at least a magnetic layer is formed on the above-mentioned glass substrate for a magnetic disk.

  The components based on the technical idea of the magnetic disk glass substrate manufacturing system described above and the description thereof are also applicable to the magnetic disk glass substrate and the magnetic disk.

  According to the present invention, the operator can prevent the occurrence of further surface defects by identifying the process causing the surface defect of the glass substrate and repairing the process.

  First, the glass substrate for magnetic disks according to this embodiment will be described. FIG. 1 is a view for explaining a glass substrate for a magnetic disk according to the present embodiment, and FIG. 1 (a) is a perspective view of the glass substrate for a magnetic disk. The magnetic disk glass substrate 200 has a disk shape, and an inner hole is formed at the center thereof. Since the main surface 210 is an area for recording and reproducing information, the main surface 210 is substantially smooth for the recording head to fly.

  FIG.1 (b) is XX sectional drawing of Fig.1 (a). The magnetic disk glass substrate 200 is interposed between a main surface 210 serving as an information recording / reproducing area, an end surface 220 orthogonal to the main surface 210, and the main surface 210 and the end surface 220. And a chamfered surface 230. In addition, since the boundary between the end surface 220 and the chamfered surface 230 may become unclear due to the end surface polishing process described later, in this embodiment, the end surface 220 and the chamfered surfaces 230 on both sides constitute a single curved surface. Including the case of doing.

  FIG. 2 is a block diagram showing a manufacturing system of a magnetic disk glass substrate according to the present embodiment. The manufacturing system 100 includes one or more processes for manufacturing the magnetic disk glass substrate 200, which include a second polishing process 102, an enhanced cleaning process 104, and a final cleaning process 106. The final cleaning step 106 includes a pre-cleaning step 106a using a water flow and a scrub cleaning step 106b using a cleaning pad. In the present embodiment, the glass substrate 200 is manufactured through the final steps 102, 104, and 106 after various preceding steps.

  The manufacturing system 100 includes a server 110, and the server 110 includes a database 112. The database 112 is a storage unit that stores surface defect maps 120a to 120d that typically indicate surface defects that occur on the glass substrate 200 when there is an abnormality in the processes of the steps 102, 104, 106a, and 106b.

  These surface defect maps 120a to 120d are accumulated in the database 112 as indicated by dotted lines 103, 105, 107, and 109 from the respective processes 102, 104, 106a, and 106b while a normal manufacturing process is in operation. ing. The map may be input and accumulated by the manual operation of the worker 408. In FIG. 2, only one map corresponds to one process, but a plurality of maps may correspond.

  Further, processes that cause surface defects are not limited to the processes 102, 104, 106a, and 106b. Any process that can store a surface defect map in the database 112 in advance can be identified as the cause of the surface defect.

  The information corresponding to each process 102, 104, 106a, 106b is not limited to the surface defect maps 120a-120d, and a predetermined feature amount extracted from the map may be stored. The feature amount may be a correlation coefficient when the map is viewed as a graph, the type and number of defects, distribution, coordinates, and the like.

  After passing through step 106, the glass substrate 200 is detected for surface defects by a surface defect detector (AOI) 130 before being packed. Surface defects may be detected by OSA.

  FIG. 3 is a diagram showing how surface defects are detected by the surface defect detection apparatus of FIG. The surface defect detection device 130 includes two types of lasers 302 (302a, 302b), four types of detectors 304 (304a, 304b, 304c, 304d), and a mirror 306.

  The laser 302a is a semiconductor laser having a wavelength of 780 ± 15 nm and a beam diameter of 120 μm × 15 μm, and the laser 302b is a semiconductor laser having a wavelength of 670 ± 10 nm and a beam diameter of 2000 μm × 7005 μm. The detector 304 is composed of a photo detector.

  FIG. 4 is an explanatory diagram for explaining defects that can be detected by the detector 304 of the surface defect detection device 130 of FIG. 3. The defects that can be detected by the surface defect detection device 130 mainly include a convex portion 140 and a concave portion 142.

When inspected by the detector 304a using the laser 302a, the scattered light reflected from the defect contained on the main surface of the magnetic disk glass substrate 200 is detected. Thereby, the detector 304a can detect a deposit or a recess of about 0.1 μm ² . When the detector 304b is inspected using the laser 302a, a change in the amount of directional scattered diffracted light reflected from a defect included on the main surface of the magnetic disk glass substrate 200 is detected. Thereby, the detector 304b can detect a deposit and a recess of about 0.1 μm ² . When the inspection is performed by the detector 304c using the laser 302a, an increase or decrease in the amount of specular reflection light from a defect included on the main surface of the magnetic disk glass substrate 200 is detected. Accordingly, the detector 304c can detect the convex portion 140 and the concave portion that are less likely to cause scattering and diffraction.

  When the detector 304d is inspected using the laser 302b, an increase or a decrease in the amount of specular reflection light from a defect included on the main surface of the magnetic disk glass substrate 200 is detected. Thus, the detector 304d can detect the gentle convex portion 140 and the gentle concave portion that are less likely to cause scattering and diffraction.

  Next, the in-plane position of the defect included in the magnetic disk glass substrate 200 is specified based on one or both of the measured light intensity and displacement, and the surface defect 402 is created.

  FIG. 5 is a diagram showing another example of the surface defect map stored in advance in the database of FIG. The surface defect map 120e is an example of a map when there is equipment damage in the final cleaning process 106, and surface defects concentrate on a limited area at one end of the glass substrate. The surface defect map 120f is an example of a map in the case where the pad in the scrub cleaning process 106b bites foreign matter.

  Instead of one map corresponding to the cause of the surface defect, three maps may be stored in the database 112 as shown in the example of FIG. Each map has a variety of causes, but is specific to the process caused by an abnormality occurring in any process.

  A computer 400 in FIG. 2 includes a control unit 401, a recognition unit 404 and a notification unit 406 controlled by the control unit 401. When the surface defect 402 is input from the surface defect detection apparatus 130 to the computer 400, the recognition unit 404 refers to the database 112 and recognizes a similar object to the surface defect 402 from the surface defect maps 120a to 120d. .

  The recognition performed by the recognition unit 404 may use, for example, a shortest distance method that is performed by directly matching a surface defect and a surface defect map as an image. The shortest distance method is a method of obtaining the “distance” between images by squaring and adding the differences between corresponding pixels constituting the image. In the present application, the smaller the “distance” is, the more similar the images are. You may determine with images being similar when it becomes below a predetermined threshold. The information recorded in the database 112 is not limited to the surface defect map itself, but may be features such as a correlation coefficient, the type and number of defects, distribution, and coordinates when the map is viewed as a graph.

  In that case, the recognition unit 404 extracts the same feature as that recorded in the database 112 from the surface defect 402. Such a feature may be freely used as a condition for recognizing a similar surface defect map. For example, if the “distance” between images according to the shortest distance method is within a predetermined range and the number of defects is within a predetermined range, a rule such as recognizing that the map is similar to the surface defect is stored in the database. 112 may be provided. Of course, even if a glass substrate has a large number of individual defects so as to be determined as a defective product, it may not be similar to any surface defect map. In that case, the cause of the surface defect is unknown. On the other hand, it is natural that a plurality of surface defect maps are similar to a certain surface defect. In this case, it can be assumed that the surface defect is caused by multiple causes.

  A notification unit 406 included in the computer 400 is a notification unit that notifies a process corresponding to a surface defect map recognized as being similar to a surface defect. The notification may be performed by displaying the process in which an abnormality has occurred and the content of the abnormality on the display device (not shown) of the computer 400 or notifying the worker 408 by voice.

  Thereby, the worker 408 can prevent the occurrence of further surface defects by identifying the process causing the surface defect of the glass substrate 200 and repairing the process. When a plurality of processes are notified, a plurality of processes may be investigated and repaired.

  If equipment used in the process, cleaning tank, etc. breaks down, repair by the operator 408 is required. However, if there is an abnormality in the parameters set for operating the process, the process itself is notified. It is preferable to change the setting automatically.

  The notification unit 406 may notify the process corresponding to the same surface defect map only when it is recognized that any one of the same surface defect maps is similar to the surface defects 402 of a predetermined number or more of glass substrates.

  This is because the reliability of the notification function is improved by notifying only when it is recognized that a specific surface defect map is similar to the plurality of surface defects 402.

  The recognition unit 404 may recognize a similar surface defect map only when the number of individual defects included in the surface defect 402 detected by the surface defect detection device 130 is a predetermined number or more.

  This is because it cannot be said that there is an abnormality in the process for a glass substrate having a non-defective product level with the number of surface defects equal to or less than a predetermined number, and in this case, useless recognition processing is omitted.

(Example)
Embodiments of a glass disk substrate manufacturing system, a magnetic disk glass substrate, and a magnetic disk to which the present invention is applied will be described below. The glass substrate 200 for magnetic disk and the magnetic disk are 0.8 inch type disk (inner diameter 6 mm, outer diameter 21.7 mm, plate thickness 0.381 mm), 1.0 inch type disk (inner diameter 7 mm, outer diameter 27.4 mm). , Plate thickness 0.381 mm), 1.8 inch type magnetic disk (inner diameter 12 mm, outer diameter 48 mm, plate thickness 0.508 mm) and the like. Further, it may be manufactured as a 2.5 inch type disc or a 3.5 inch type disc.

(1) Data accumulation process While each of the following processes is in operation, a surface defect map that typically indicates a surface defect that occurs on the glass substrate when there is an abnormality in the process of each process is accumulated in advance from each process. Is done. The accumulation of the map may be performed based on the experience of the operator 408. The number of surface defect maps is not necessarily one per process. There are also processes that do not have a surface defect map.

(2) Shape processing step and first lapping step Examples of the material of the glass substrate 200 in the present embodiment include soda lime glass, aluminosilicate glass, borosilicate glass, and crystallized glass. Among them, aluminosilicate glass is preferable. is there. Since the aluminosilicate glass is smooth and has high rigidity, the magnetic spacing, particularly the flying height of the magnetic head, can be more stably reduced. Aluminosilicate glass can obtain high rigidity and strength by chemical strengthening.

First, the melted aluminosilicate glass was molded into a disk shape by direct pressing using an upper mold, a lower mold, and a barrel mold to obtain an amorphous plate glass. In addition, the glass for chemical strengthening was used as aluminosilicate glass. In addition to direct pressing, a disk-shaped glass substrate 200 for a magnetic disk may be obtained by cutting a sheet glass formed by a downdraw method or a float method with a grinding wheel. As the aluminosilicate _glass, SiO 2: 58 to 75 _{wt%, Al} 2 O 3: _{5~23 wt%,} Li 2 O: 3 to 10 _wt%, Na 2 O: 4 to 13 principal component weight% The chemically strengthened glass contained as was used.

  Next, both main surfaces of the plate glass were lapped to form a disk-shaped glass base material. This lapping process was performed using alumina free abrasive grains with a double-sided lapping apparatus using a planetary gear mechanism. Specifically, the lapping platen is pressed from above and below on both sides of the plate glass, a grinding liquid containing free abrasive grains is supplied onto the main surface of the plate glass, and these are moved relatively to perform lapping. went. By this lapping process, a glass base material having a flat main surface was obtained.

(3) Cutting process (coring, forming)
Next, the glass base material was cut using a diamond cutter, and a disk-shaped glass substrate was cut out from the glass base material. Next, using a cylindrical diamond drill, an inner hole was formed in the central portion of the glass substrate to obtain an annular glass substrate 200 (coring). Then, the inner peripheral end face and the outer peripheral end face 220 were ground with a diamond grindstone and subjected to predetermined chamfering (forming).

(4) Second Lapping Step Next, the second lapping process was performed on both main surfaces 210 of the obtained glass substrate 200 in the same manner as in the first lapping step. By performing this second lapping step, the fine uneven shape formed on the main surface in the cutting step and end surface polishing step, which are the previous steps, can be removed in advance, and the subsequent polishing step on the main surface 210 can be performed. It can be completed in a short time.

(5) End surface polishing step Next, end surface polishing of the outer periphery of the glass substrate 200 is performed. First, the end face 220 is polished independently prior to the chamfered face 230. The polishing method may be, for example, a method in which a plurality of glass substrates 200 are simultaneously polished with a brush, but the machining allowance increases. Therefore, for example, a single wafer polishing method may be used.

  Subsequently, the chamfered surface 230 was subjected to mirror polishing. Thereby, the difference of the surface roughness in the perimeter of the outer periphery of the chamfered surface 230 of one glass substrate 200 became the range of 0.001 micrometer or less. And the glass substrate 200 which finished the end surface grinding | polishing process was washed with water. By this end face polishing step, the end face 220 of the glass substrate 200 was processed into a mirror state that can prevent the precipitation of sodium and potassium.

  In this embodiment, the chamfered surface 230 is polished after the end portion is polished. However, this order is arbitrary, and the end face 220 may be polished after the chamfered surface 230 is polished first.

  Next, regarding the inner peripheral end surface, a glass substrate block in which a large number of sheets are laminated may be formed, and the chamfered inner peripheral end portion may be simultaneously polished with a brush roll. At this time, as the abrasive grains, a slurry (free abrasive grains) containing cerium oxide abrasive grains was used.

(6) Main surface polishing step As the main surface polishing step, first, a first polishing step was performed. This first polishing process is mainly intended to remove scratches and distortions remaining on the main surface 210 in the lapping process described above. In the first polishing step, the main surface 210 was polished using a hard resin polisher by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, cerium oxide abrasive grains were used.

  The glass substrate 200 after the first polishing step was sequentially immersed in cleaning baths of neutral detergent, pure water, and IPA (isopropyl alcohol) to be cleaned.

  Next, a second polishing step was performed as the main surface polishing step. The purpose of the second polishing step is to finish the main surface 210 in a mirror shape. In the second polishing step, mirror polishing of the main surface 210 was performed using a soft foam resin polisher by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, cerium oxide abrasive grains finer than the cerium oxide abrasive grains used in the first polishing step were used.

  The glass substrate 200 after the second polishing step was sequentially immersed in cleaning baths of neutral detergent, pure water, and IPA (isopropyl alcohol) and cleaned. Note that ultrasonic waves were applied to each cleaning tank.

(7) Chemical strengthening process Next, the glass substrate 200 which finished the above-mentioned lapping process and polishing process was chemically strengthened. For chemical strengthening, a chemical strengthening solution prepared by mixing potassium nitrate (60%) and sodium nitrate (40%) is prepared, and the chemically strengthened solution is heated to 400 ° C. and the cleaned glass substrate 200 is heated to 300 ° C. This was done by preheating and immersing in a chemical strengthening solution for about 3 hours. In this immersion, in order to chemically strengthen the entire surface of the glass substrate 200, the plurality of glass substrates 200 were held in the holder so as to be held by the end surfaces 220.

  Thus, by immersing in the chemical strengthening solution, the lithium ions and sodium ions in the surface layer of the glass substrate 200 are replaced with sodium ions and potassium ions in the chemical strengthening solution, respectively, and the glass substrate 200 is strengthened. The thickness of the compressive stress layer formed on the surface layer of the glass substrate 200 was about 100 μm to 200 μm.

  The glass substrate 200 that had been subjected to the chemical strengthening treatment was immersed in a water bath at 20 ° C. for rapid cooling and maintained for about 10 minutes. And the glass substrate 200 which finished quenching was immersed in the concentrated sulfuric acid heated at about 40 degreeC, and was wash | cleaned.

(8) Final cleaning step Further, the glass substrate 200 after the sulfuric acid cleaning was cleaned by immersing in a cleaning bath of pure water and IPA (isopropyl alcohol) sequentially (pre-cleaning step 106a to scrub cleaning step 106b). In addition, ultrasonic waves were applied to each cleaning tank.

  As described above, by applying the first lapping step, the cutting step, the end surface polishing step, the second lapping step, the first and second polishing steps, the chemical strengthening step, and the final cleaning step, a flat, smooth, high rigidity A glass substrate 200 for a magnetic disk was obtained.

(9) Inspection Step The main surface 210 of the obtained magnetic disk glass substrate 200 was inspected for smoothness. The inspection process uses light such as a surface defect detector (AOI: Automatic Optical Inspection) and an OSA (Optical Surface Analyzer) to irradiate the magnetic disk glass substrate 200 with light and reflect the light from the magnetic disk glass substrate 200. One or both of the strength and the displacement is measured, and whether or not the deposit, the concave portion 142 and the convex portion 140 are present is measured, and the substrate state is evaluated.

(10) Recognition / notification process The recognition unit 404 recognizes the surface defect 402 obtained by the surface defect detection device 130 from the surface defect maps 120a to 120d. When it is recognized that any one of the same surface defect maps is similar to the surface defects 402 of the glass substrate of a predetermined number or more, the notification unit 406 notifies the worker 408 of a process corresponding to the same surface defect map.

  As a result, the number of cases where the cause can be identified for the surface defects that could be identified only by skilled workers has increased dramatically, and the number of cases where the cause is determined to be unknown is reduced by 23%.

(11) Packing process 25 glass substrate 200 for magnetic disks was accommodated in a case, 4 cases were piled up, the 1st packing bag made from an aluminum laminated film was deaerated, hermetically packed, and it was set as the package. Next, the packaging body was deaerated from the second packaging bag made of a plastic film and further hermetically sealed to obtain a packaging body.

  As described above, the glass substrate 200 is housed in the case, and the double packing body in which the second packing bag and the first packing bag are double-sealed and packaged is shipped from the glass substrate manufacturing facility, and the ship or airplane And transported to a magnetic disk manufacturing facility by a train or the like.

(12) Magnetic disk manufacturing process (film formation process)
A film forming step of forming at least a magnetic layer on the glass substrate for a magnetic disk packed using the above packing body is performed.

  On both surfaces of the glass substrate 200 obtained through the packaging method and the manufacturing process described above, an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoTaZr-based alloy, an underlayer made of Ru, and a CoCrPt-based alloy on the surface of the glass substrate 200 A perpendicular magnetic recording disk was manufactured by sequentially forming a perpendicular magnetic recording layer made of, a protective layer made of hydrogenated carbon, and a lubricating layer made of perfluoropolyether. Although this configuration is an example of a configuration of a perpendicular magnetic disk, a magnetic layer or the like may be configured as an in-plane magnetic disk.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these naturally have the attributes of the technical scope of the present invention. It is understood.

  The present invention can be used for a magnetic disk glass substrate manufacturing system, a magnetic disk glass substrate, and a magnetic disk.

It is a figure explaining the glass substrate for magnetic discs concerning this embodiment. It is a block diagram which shows the manufacturing system of the glass substrate for magnetic discs concerning this embodiment. It is a figure which shows the mode of the surface defect detection by the surface defect detection apparatus of FIG. It is explanatory drawing for demonstrating the defect which the detector of the surface defect detection apparatus of FIG. 3 can detect. It is a figure which shows the other example of the surface defect map previously memorize | stored in the database of FIG. It is a table | surface which shows the result of an endurance test in the environment of.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Manufacturing system 102 ... 2nd grinding | polishing process 104 ... Strengthening cleaning process 106 ... Final cleaning process 110 ... Server 112 ... Database 130 ... Surface defect detection apparatus 140 ... Convex part 142 ... Concave part 200 ... Glass substrate 401 ... Control part 402 ... Surface Defect 404 ... recognition unit 406 ... notification unit 408 ... worker

Claims (5)

A storage means for storing a surface defect map typically indicating surface defects generated in the glass substrate when there is an abnormality in the processing of each step, corresponding to one or more steps for manufacturing a glass substrate for magnetic disk; ,
A surface defect detecting means for detecting a surface defect of the glass substrate for magnetic disk manufactured through the one or more steps;
Recognition means for recognizing a surface defect map similar to the surface defect;
Informing means for informing a process corresponding to the surface defect map recognized as being similar to the surface defect;
The manufacturing system of the glass substrate for magnetic discs characterized by including these.   The notification means notifies the process corresponding to the same surface defect map only when the recognition means recognizes that any one of the same surface defect maps is similar to the surface defects of the glass substrate of a predetermined number or more. The glass substrate system for a magnetic disk according to claim 1.   2. The recognizing unit recognizes the similar surface defect map only when the number of individual defects included in the surface defect detected by the surface defect detecting unit is a predetermined number or more. Or a system for producing a glass substrate for a magnetic disk as described in 2 above.   A glass substrate for a magnetic disk, which is manufactured using the system for manufacturing a glass substrate for a magnetic disk according to any one of claims 1 to 3.   5. A magnetic disk comprising at least a magnetic layer formed on the glass substrate for a magnetic disk according to claim 4.

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