JP4623652B2 - Manufacturing method of magnetic recording disk - Google Patents

Description

  The present invention relates to a method of manufacturing a magnetic recording disk (including a magneto-optical recording disk) employing an immersion film forming method when a thin film such as a lubricating layer is formed on the surface of a magnetic recording disk substrate.

A magnetic recording disk has a structure in which at least a magnetic layer, a protective layer, and a lubricating layer are laminated in this order on the surface of a non-magnetic substrate such as a glass substrate or a metal substrate having a central hole. The lubricating layer is often formed by a dip film forming method. When adopting such an immersion film forming method, a plurality of magnetic recording disk substrates are collectively supported by a substrate support inserted into the center hole so that a plurality of substrates can be processed at once. In general, a dipping operation into a chemical solution and a pulling-up operation from the chemical solution are performed (see Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 10-310871 JP 2000-67431 A

  As for magnetic recording disks, those having an outer diameter of 3.5 inches or 3.0 inches to 2.5 inches, and more recently, 1.0 inches have been adopted. Among such magnetic recording disks, when a magnetic recording disk having a relatively small outer diameter is manufactured, the lubricating layer is formed by the immersion film forming method using the substrate support described in Patent Documents 1 and 2. The problem that countless fine horizontal line patterns occur on the substrate may occur, and such horizontal line patterns are caused by uneven thickness of the lubricating layer. Here, the uneven thickness of the lubricating layer causes fluctuations in the air pressure required for the magnetic head to fly and causes the flying posture and the flying height of the magnetic head to be modulated. Such a defect is called a fly stiction failure and is accompanied by irregular reproduction output fluctuation, which is not preferable. In some cases, the flying magnetic head and the magnetic recording disk may come into contact with each other and cause a crash. Further, such a thickness unevenness is a problem that occurs not only when the lubricating layer is formed but also when a protective film or the like is formed by the immersion film forming method.

  In view of the above problems, the object of the present invention is to reliably prevent the occurrence of film thickness unevenness when a thin film is formed on the surface of a magnetic recording disk substrate having a relatively small outer diameter by the immersion film forming method. The object is to propose a method of manufacturing a magnetic recording disk.

  The present inventor has conducted various studies to elucidate the cause of the above problems, and as a result, when forming a thin film on a magnetic recording disk substrate having a relatively small outer diameter by the immersion film formation method, the center hole is inserted. When the magnetic recording disk substrate is pulled up from the chemical solution while the magnetic recording disk substrate is only supported by the substrate support tool, the magnetic recording disk substrate is light, so that the lower side of the magnetic recording disk substrate is in the out-of-plane direction. It has been found that fluctuations in the thickness of the thin film are likely to occur, and fluctuations around the axis passing through the support position perpendicular to the substrate support are likely to occur. In addition, it was found that the greater the specific gravity of the chemical solution, the more likely such shaking occurs.

The present invention has been achieved on the basis of such new knowledge, and is provided for a magnetic recording disk having an immersion film forming step for forming a lubricating layer on the surface of a magnetic recording disk substrate having a central hole by an immersion method. In the manufacturing method, in the immersion film forming step, a liquid surface of a chemical solution for forming the lubricating layer in a state where a plurality of magnetic recording disk substrates are supported by a substrate support inserted through the center hole, When the magnetic recording disk substrate is moved relative to the magnetic recording disk substrate to perform an immersion operation in the chemical solution and a pulling operation from the chemical solution, at least when performing the pulling operation , A receiving portion provided on an arm portion extending so as to pass under the plurality of magnetic recording disk substrates is provided on both lower ends of both sides of the magnetic recording disk substrate. Of the positions adjacent to each other in the out-of-plane direction of the disk substrate, they are arranged on both sides of the position directly below the magnetic recording disk substrate, and the receiving part is in a non-contact state with respect to the magnetic recording disk substrate It is characterized by that.

In the present invention, when the magnetic recording disk substrate is lifted from the chemical solution, the outer diameter dimension is obtained because the receiving portions of the shake preventing tool are close to the lower ends of both surfaces of the magnetic recording disk substrate. Therefore, even in a light magnetic recording disk substrate, the lower end portion of the magnetic recording disk substrate is not shaken in the out-of-plane direction, and the oscillation around the axis passing through the support position by the substrate support is not generated. Therefore, even when the thin film is formed on the surface of the magnetic recording disk substrate by the immersion film forming method, the film thickness does not vary. In addition, even when the specific gravity of the chemical solution is large, the magnetic recording disk substrate is not greatly shaken, and there is an advantage that the selection range of usable chemical solutions is widened.

In addition, among the various thin films formed on the surface of the magnetic recording disk substrate, the uneven thickness of the lubricating layer causes fluctuations in the air pressure necessary for the magnetic head to fly. Since it is necessary to suppress the uneven thickness of the lubricating layer as the distance becomes shorter, the present invention is applied when the lubricating layer is formed as the thin film on the surface of the magnetic recording disk substrate in the immersion film forming step. The effect is great. In addition, since the receiving portions are arranged on both sides of the position directly below the magnetic recording disk substrate, the lower end portion of the magnetic recording disk substrate can be reliably prevented from shaking in the out-of-plane direction and supported by the substrate support. The shaking around the axis passing through the position vertically can also be reliably prevented.

  When the present invention is applied to the case where a thin film is formed on the surface of a magnetic recording disk substrate having an outer diameter of 2.5 inches or less because it is likely to occur when the magnetic recording disk substrate is light, The effect is remarkable.

In the present invention, a chamfered portion is formed on both sides of the outer peripheral wall by chamfering the boundary between the outer peripheral end and both surfaces of the magnetic recording disk substrate at the outer peripheral end of the magnetic recording disk substrate. The receiving portion is close to the boundary portion between the outer peripheral wall surface and the chamfered portion in the out-of-plane direction of the magnetic recording disk substrate among the lower end portions of both surfaces of the magnetic recording disk substrate. Is preferred.

  In the present invention, the anti-sway tool includes a linear body stretched on the arm portion so as to form a plurality of valley portions at intersections along the longitudinal direction above the arm portion, and the magnetic recording A lower end portion of the disk substrate is located inside a valley portion of the linear body, and a ridge line portion sandwiching the valley portion on both sides of the linear body serves as the lower end of both surfaces of the magnetic recording disk substrate. It is preferable that it is close to the part. With this configuration, when the magnetic recording disk substrate is shaken, it is a linear body that contacts, and the contact portion is extremely small. For this reason, even when a chemical solution is held between the magnetic recording disk substrate and the linear body, no liquid pool is generated in the magnetic recording disk substrate. In addition, when the outer peripheral edge close to the shake prevention tool comes out of the liquid surface of the chemical solution, the droplets that try to accumulate at the outer peripheral edge are pulled toward the linear body and remain as a liquid pool at the outer peripheral edge. Absent. Therefore, it is possible to reliably prevent a liquid pool from being formed at the outer peripheral end of the magnetic recording disk substrate.

In the present invention, the vibration preventing member is a Rukoto a pair arranged in parallel on both sides sandwiching the position just below the magnetic recording disk substrate, wherein the receiving portion is disposed on both sides sandwiching the position just below the magnetic recording disk substrate In this case, at least when the pulling operation is performed, the plurality of sheets are extended between the pair of shake preventing tools so as to pass directly under the plurality of magnetic recording disk substrates. It is preferable that a liquid pool removing tool for removing the chemical solution from each lower end of the magnetic recording disk substrate is disposed in a non-contact state with the magnetic recording disk substrate. If a liquid pool remover is placed directly below the magnetic recording disk substrate, the liquid that tends to accumulate at the lower end of the magnetic recording disk substrate when the lower end of the magnetic recording disk substrate comes out of the liquid surface of the chemical solution. The droplet is pulled toward the liquid pool remover and does not remain as a liquid pool on the magnetic recording disk substrate. Therefore, it is possible to reliably prevent a liquid pool from being formed on the outer peripheral edge of the magnetic recording disk substrate.

  In the present invention, the substrate support tool includes a support arm extending so as to penetrate the center hole, and a plurality of troughs formed at intersections along the longitudinal direction of the support arm at an upper portion of the support arm. Each of the plurality of magnetic recording disk substrates is supported in a state where an inner peripheral end portion of the center hole is floated from the support arm at the valley portion. It is preferable. When the magnetic recording disk substrate is supported by the substrate support inserted through the center hole, if the inner peripheral wall of the magnetic recording disk substrate is lifted from the support arm, the magnetic recording disk substrate is in contact with the support. It is a thread, and the contact portion is extremely small. For this reason, even when a chemical solution is held between the magnetic recording disk substrate and the linear body, no liquid pool is generated in the magnetic recording disk substrate. In addition, when the inner peripheral edge of the portion supported by the substrate support comes out of the liquid surface of the chemical solution, the droplets that accumulate on the inner peripheral edge are pulled toward the support yarn, and the liquid is applied to the inner peripheral edge. It does not remain as a pool. Therefore, it is possible to reliably prevent a liquid pool from being formed at the inner peripheral end of the magnetic recording disk substrate.

  In the present invention, when performing the lifting operation, the magnetic recording disk substrate is lifted from the liquid surface by raising the magnetic recording disk substrate, and the liquid surface of the chemical liquid is lowered. Accordingly, it is possible to employ a configuration in which the magnetic recording disk substrate is pulled up from the liquid surface. Among these configurations, the latter case has an advantage that the unevenness of the film thickness hardly occurs in the lubricating layer because the vibration of the driving portion is not directly transmitted to the magnetic recording disk substrate.

  In the present invention, when the magnetic recording disk substrate is lifted from the chemical solution, the shake receiving tool receiving portions are opposed to the lower end portions on both sides of the magnetic recording disk substrate. Even for a magnetic recording disk substrate with a relatively small diameter, the bottom of the magnetic recording disk substrate is shaken in the out-of-plane direction or around the axis passing through the support position perpendicular to the substrate support. Does not occur. Therefore, even when the thin film is formed on the surface of the magnetic recording disk substrate by the immersion film forming method, the film thickness does not vary. In addition, even when the specific gravity of the chemical solution is large, the magnetic recording disk substrate is not greatly shaken, and there is an advantage that the selection range of usable chemical solutions is widened.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing to be referred to, the scale and magnification are made different for each layer and each member for easy recognition on the drawing.

(Outline of magnetic recording disk and manufacturing method thereof)
1A and 1B are a plan view showing a magnetic recording disk and a schematic sectional view of the magnetic recording disk, respectively. As shown in these drawings, in the magnetic recording disk 1 of this embodiment, an underlayer 12, a magnetic layer 13, a protective layer 14, and a lubricating layer 15 are provided on a surface 110 of a circular nonmagnetic substrate 11 having a center hole 111. It has a structure laminated in this order. The nonmagnetic substrate 11 is made of, for example, chemically tempered glass such as aluminosilicate glass. The surface 110 of the nonmagnetic substrate 11 has a mirror surface such that the surface roughness is 0.3 nm or less for Ra and 3 nm or less for Rmax. Polished. In the nonmagnetic substrate 11, the inner peripheral end 112 and the outer peripheral end 113 are each chamfered.

  While explaining the outline of the manufacturing process of such a magnetic recording disk 1, the structure of each thin film is demonstrated below. To manufacture the magnetic recording disk 1, first, the underlayer 12 is formed on the surface 110 of the nonmagnetic substrate 11 by sputtering or the like. The underlayer 12 is a CrW thin film having a thickness of 10 nm, for example, and is formed in order to improve the crystal structure of the magnetic layer 13.

  Next, the magnetic layer 13 is formed on the upper layer of the underlayer 12 by sputtering or the like. The magnetic layer 13 is made of, for example, a CoCrPtB alloy having a thickness of 15 nm. The contents of Co, Cr, Pt, and B in the magnetic layer 13 are, for example, Co: 62 at%, Cr: 20 at%, Pt: 12 at%, and B: 6 at%.

  Next, the protective layer 14 is formed on the upper layer of the magnetic layer 13 by CVD or sputtering. The protective layer 14 is made of hydrogenated carbon having a thickness of 5 nm, for example, and has a function of improving the wear resistance and protecting the magnetic layer 13.

  Next, as will be described in detail later, a lubricating layer 15 is formed on the surface of the protective layer 14 by an immersion film forming method. The lubrication layer 15 has a function of mitigating impact when coming into contact with the magnetic head, and is composed of a thin perfluoropolyether layer having a thickness of 3 nm or less. Here, the lubricating layer 15 tends to be thinned to 2 nm or less, for example, about 1.0 nm.

(Immersion film forming equipment for lubricating layer formation)
FIG. 2 is an explanatory view schematically showing the configuration of the immersion film forming apparatus used in the immersion film forming method according to the present invention. FIGS. 3A and 3B are respectively an explanatory view when a state in which a plurality of magnetic recording disk substrates are mounted on the substrate processing tool used in the immersion film forming apparatus according to the present invention is viewed from the front side, and FIG. It is explanatory drawing when it sees from the direction.

  In this embodiment, when the lubricating layer 15 is formed on the intermediate product (hereinafter referred to as the magnetic recording disk substrate 10) in which the base layer 12, the magnetic layer 13, and the protective layer 14 are sequentially laminated on the surface 110 of the nonmagnetic substrate 11. The immersion film forming apparatus described below is used. As shown in FIG. 2, the immersion film forming apparatus 100 includes a chemical tank 21 for storing a chemical liquid 22 for forming the lubricating layer 15 and a substrate for collectively processing a plurality of magnetic recording disk substrates 10. And a processing tool 200. Here, the immersion film forming apparatus 100 moves up and down to drive the substrate processing tool 200 in the vertical direction in order to perform an operation of immersing the plurality of magnetic recording disk substrates 10 in the chemical liquid 22 and an operation of pulling up from the chemical liquid 22. At least one of an apparatus, an elevating device that drives the chemical liquid tank 21 in the vertical direction, and a liquid level raising and lowering apparatus that moves the liquid level in the chemical liquid tank 21 up and down is configured. However, in the case of an elevating device that drives the chemical tank 21 in the vertical direction or a liquid level lifting apparatus that moves the liquid level in the chemical tank 21 up and down, the vibration of the drive portion is directly transmitted to the magnetic recording disk substrate 10. Therefore, there is an advantage that film thickness unevenness hardly occurs in the lubricating layer 15.

  As shown in FIGS. 2, 3 (a), and 3 (b), the substrate processing tool 200 includes a substrate support 300 that is inserted into each central hole 111 of the plurality of magnetic recording disk substrates 10. While the plurality of magnetic recording disk substrates 10 are supported by the substrate support 300, the immersion operation and the pulling-up operation from the chemical solution 22 are performed in the chemical solution 22. The substrate processing tool 200 includes a shake prevention tool 400 that extends in parallel with the substrate support 300 and passes below the plurality of magnetic recording disk substrates 10. Here, a pair of anti-vibration tools 400 are arranged in parallel on both the left and right sides of the magnetic recording disk substrate 10. Further, the substrate processing tool 200 includes a liquid pool removing tool 500 extending between the pair of shake preventing tools 400 so as to pass directly under the plurality of magnetic recording disk substrates 10. 500 is fixed in parallel with the substrate support tool 100 and the shake prevention tool 400. Accordingly, the plurality of magnetic recording disk substrates 10 are subjected to the dipping operation and the pulling operation from the chemical solution while the inner peripheral end 112 of the center hole 111 is supported by the substrate support 300 during the immersion operation and the pulling operation from the chemical solution. Two shake prevention tools 400 and one liquid pool removal tool 500 are arranged below the plurality of magnetic recording disk substrates 10.

(Configuration of substrate support)
4A and 4B are a side view and a plan view, respectively, of the substrate support used in the immersion film forming apparatus according to the present invention. FIGS. 5A and 5B are a side view of a support arm used in the substrate support shown in FIG. 4 and an explanatory view showing a method of tensioning a support thread on the support arm.

  As shown in FIGS. 3A, 3B, 4A, and 4B, the substrate support 300 shown in FIGS. A pair of support arms 310 inserted into the respective center holes 111 and an inner peripheral end portion 112 of the center hole 111 of the magnetic recording disk substrate 10 placed on the support arms 310 are placed. And a support thread 320 that supports the inner peripheral end 112 of the magnetic recording disk substrate 10 in a state of floating from the support arm 310. More specifically, first, as shown in FIGS. 3 (b), 4 (a), 4 (b) and FIGS. 5 (a), 5 (b), the pair of support arms 310 has an upper end portion. It is formed in a sawtooth shape, and triangular peaks 311 and inverted trapezoidal valleys 312 are alternately formed in the longitudinal direction. Further, as shown in FIG. 4 (b), a notch 313 is formed at the top of each peak portion 311 in a substantially middle portion in the thickness direction of the support arm 310, while at a position below the valley portion 312. Is formed with a through hole 314 that penetrates the support arm 310 in the thickness direction. The support yarn 320 is inserted from the inner side of the support arm 310 (the side facing the other support arm 310) to the outer side, and then is inserted into the peak portion 311 next to the peak portion 311 in the vicinity of the through hole 314. It is latched to the formed notch 313, and then inserted from the outside of the support arm 310 into the through hole 314 formed corresponding to the next trough 312 of the trough 312 in the vicinity of this crest 311. Furthermore, every other notch 313 of the peak portion 311 spans every other notch 313 by being inserted from the inside into the through-hole 314 at the position where it has returned by one. Further, such a latching operation is performed by shifting one pitch with respect to the peak portion 311 using another support yarn 320, so that the support yarn 320 is closer to the outer side of the support arm 310 of the trough portion 312 and the intersection portion 325. Is stretched to form. As a result, on the upper part of the support arm 310, the support thread 320, along the longitudinal direction, a peak portion 321 having a hooking portion to the notch 313 as a top portion, and a valley portion 322 having a crossing portion 325 as a valley bottom, Are arranged alternately.

  Accordingly, when the substrate support 300 is inserted into each central hole 111 of the magnetic recording disk substrate 10, the inner peripheral end 112 of the magnetic recording disk substrate 10 is placed inside the valley 322. The inner peripheral end 112 of the substrate 10 is supported so as to float from the support arm 310, and the magnetic recording disk substrate 10 is in a vertical posture due to its own weight. Here, since the inner peripheral end portion 112 of the nonmagnetic substrate 11 is chamfered, the inner peripheral end portion 112 of the magnetic recording disk substrate 10 is provided on both sides in the thickness direction of the inner peripheral wall surface 112a. Chamfered portions 112 b and 112 c are formed, and a boundary portion between the inner peripheral wall surface 112 a and the chamfered portions 112 b and 112 c is in contact with the support yarn 320.

  As the support thread 320, a nylon fishing line, a fluorocarbon fishing line, a metal fishing line, a wire, or the like is used, and a thickness of 0.05 to 0.5 mm is used. A particularly desirable range is preferably 0.2 to 0.3 mm for a nylon fishing line or a fluorocarbon fishing line, and 0.05 to 0.1 mm for a metal fishing line or wire. Here, the contact portion between the support yarn 320 and the magnetic recording disk substrate 10 has an effect that the chemical liquid 22 accumulated in the contact portion is attracted by the support yarn 320 and removed from the magnetic recording disk substrate 10. The attraction action depends on the thickness of the support yarn 320. If the support yarn 320 is too thin, not only the excess chemical solution 22 is removed, but also yarn breakage occurs. On the other hand, as the thickness increases, the attracting action increases, and the excess chemical solution from the magnetic recording disk substrate 10 is favorably removed. The interval of the intersections 325 determines the interval of the magnetic recording disk substrate 10 to be supported. If it is too wide, the number of processed sheets decreases and the production efficiency deteriorates. In view of these, the range of 3 to 9 mm is suitable. On the other hand, if the angle θ1 (see FIG. 3B) formed by the support yarn 320 and the magnetic recording disk substrate 10 is too large, the magnetic recording disk substrate 10 placed on the intersection 325 becomes easy to move and decreases. If it is too large, the magnetic recording disk substrate 10 contacts the peak 311 or the support arm 11 cannot geometrically be inserted into the central hole 111 of the magnetic recording disk substrate 10, so that the angle θ1 is 30 °. A range of ˜80 ° and a range of 45 ° to 70 ° are preferable.

(Configuration of anti-vibration device)
FIGS. 6A and 6B are a side view and a plan view of the shake preventing tool used in the immersion film forming apparatus according to the present invention, respectively. 6A and 6B, the arm portion and the linear body used in the shake preventing tool are shown in FIGS. 5A and 5B. Since it is the same as the method of tensioning the support arm and the support thread, the method of tensioning the arm portion and the linear body will be described with reference to FIGS. 5 (a) and 5 (b).

  As shown in FIGS. 5A, 5B, 6A, and 6B, the shake preventing device 400 shown in FIGS. A pair of arm portions 410 extending so as to pass through the lower position of the magnetic recording disk, and a receiving portion that is stretched around the arm portion 410 and is close to the lower end portions of both sides of the outer peripheral end portion 113 of the magnetic recording disk substrate 10. The linear body 420 which comprises this is provided. More specifically, first, as shown in FIGS. 3 (b), 5 (a), 5 (b), and 6 (a), 6 (b), the pair of arm portions 410 are both upper end portions. Are formed in a sawtooth shape, and triangular peaks 411 and inverted trapezoidal valleys 412 are alternately formed in the longitudinal direction. Further, as shown in FIG. 6 (b), a notch 413 is formed at the center of the arm portion 410 in the thickness direction at the top of each peak portion 411, while at a position below the valley portion 412. A through hole 414 that penetrates the arm portion 410 in the thickness direction is formed. The linear body 420 is inserted from the inner side of the arm part 410 (the side facing the other arm part 410) to the outer side, and then the peak part 411 next to the peak part 411 near the through hole 414. And then inserted into the through-hole 414 formed corresponding to the next valley 412 of the valley 412 close to the peak 413 from the outside of the arm 410. Further, every other notch 413 of the peak portion 411 is stretched over by being inserted from the inside into the through-hole 414 in the position where it has returned one more. Further, such a latching operation is performed by shifting the pitch 411 with respect to the peak portion 411 using another linear body 420, so that the linear body 420 intersects near the outer side of the arm portion 410 of the valley portion 412. It is spanned so as to form a part 425. As a result, on the upper portion of the arm portion 410, the linear body 420, along the longitudinal direction, along the longitudinal direction, a peak portion 421 having a hooking portion to the notch 413 and a valley portion 422 having a crossing portion 425 as a valley bottom. And are arranged alternately.

Therefore, when the shake preventing device 400 is disposed below the magnetic recording disk substrate 10 and the outer peripheral end 113 of the magnetic recording disk substrate 10 is disposed inside the valley portion 422, the valley portion 422 is disposed on both sides. The sandwiched ridge portion 423 (receiving portion) is in a state of being close to the lower end portions of both surfaces of the magnetic recording disk substrate 10. Therefore, the lower end portion of the magnetic recording disk substrate 10 does not shake in the out-of-plane direction, and does not shake around the axis line passing through the support position by the substrate supporter 300 vertically. Here, since the outer peripheral end portion 113 of the nonmagnetic substrate 11 is chamfered, the outer peripheral end portion 113 of the magnetic recording disk substrate 10 has chamfered portions 113b and 113c formed on both sides of the outer peripheral wall surface 113a. The linear body 420 is located in the vicinity of the boundary between the outer peripheral wall surface 113a and the chamfered portions 113b and 113c. However, the linear member 420 of the vibration preventing member 400 is located in the vicinity of the lower end portion of the magnetic recording disk substrate 10, Yes in contact not Na.

  Here, the linear body 420 is also made of nylon fishing line, fluorocarbon fishing line, metal fishing line, wire, etc., as in the case of the support thread 320, and its thickness is in the range of 0.05 to 0.5 mm. . A particularly desirable range is 0.2 to 0.3 mm for nylon fishing line and fluorocarbon fishing line, and 0.05 to 0.1 mm for metal fishing line and wire. Further, the proximity portion between the linear body 420 and the magnetic recording disk substrate 10 has an effect that the chemical liquid 22 accumulated in the proximity portion is attracted by the linear body 420 and removed from the magnetic recording disk substrate 10. This attraction action depends on the thickness of the linear body 420. If the linear body 420 is too thin, not only the excess chemical solution 22 is removed, but also the yarn breakage occurs when the magnetic recording disk substrate 10 is shaken. . On the other hand, as the thickness increases, the attracting action increases, and the excess chemical solution from the magnetic recording disk substrate 10 is favorably removed. In addition, the space | interval of the cross | intersection part 425 is set to the same space | interval as the cross | intersection part 325 of the board | substrate support member 300, and the range of 3-9 mm is suitable. On the other hand, if the angle θ2 (see FIG. 3B) formed by the linear body 420 and the magnetic recording disk substrate 10 is excessively large, the vibration of the magnetic recording disk substrate 10 becomes large. A range of 45 ° to 70 ° is preferable in the range of 30 ° to 80 °.

(Configuration of the liquid pool remover)
The liquid pool removing tool 500 shown in FIG. 2 and FIG. 3 is composed of a bar or a plate, and, as shown in FIG. 6B, between the shake preventing tools 400 at a position directly below the disk substrate 10. Has been placed. In this state, the liquid pool removing tool 500 is located in the vicinity of the lower end portion of the magnetic recording disk substrate 10 and is not in contact therewith.

(Immersion deposition process)
In forming the lubricating layer 15 on the surface of the magnetic recording disk substrate 10 using the immersion film forming apparatus 100 shown in FIG. 2, as the chemical solution 22, a perfluoropolyether lubricant or the like is used as HFC (hydrofluorocarbon), A solution dispersed and dissolved in a fluorine-based solvent such as PFC (perfluorocarbon) is used. Here, as the perfluoropolyether-based lubricant, for example, Fomblin-Z-DOL (trade name), Fomblin-Z-Tetraol (trade name) manufactured by Solvay Solexis, etc. are used.

  On the other hand, in the substrate processing tool 200, the substrate support 300 is inserted into each central hole 111 of the plurality of magnetic recording disk substrates 10, and the plurality of magnetic recording disk substrates 10 are supported by the substrate support 300. And In this state, the shake preventing tool 400 and the liquid pool removing tool 500 are disposed below the magnetic recording disk substrate 10.

  Next, the substrate processing tool 200 is driven in a state where the liquid level of the chemical liquid 22 is lowered in the chemical liquid tank 21, and the plurality of magnetic recording disk substrates 10 mounted on the substrate processing tool 200 are placed in the chemical liquid tank 21. Deploy.

  Next, the chemical solution 22 is introduced into the chemical solution tank 21, and a plurality of magnetic recording disk substrates 10 are immersed in the chemical solution 22 (immersion operation). At that time, the substrate support 300, the shake prevention device 400, and the liquid pool removal device 500 are also immersed in the chemical solution 22.

  Next, after a predetermined time has elapsed, the chemical liquid 22 is discharged from the chemical liquid tank 21 at a constant speed, for example, at a speed at which the liquid level of the chemical liquid 22 decreases at a speed of 0.5 mm / sec. The single magnetic recording disk substrate 10 is lifted (pulling operation). As a result, the substrate support tool 300, the shake prevention tool 400, and the liquid pool removal tool 500 are also lifted from the chemical solution 22. At that time, in the magnetic recording disk substrate 10, the solvent evaporates at the portion of the chemical liquid 22 coming out from the liquid surface. Further, when the magnetic recording disk substrate 10 is pulled up when the magnetic recording disk substrate 10 is lifted, the ridge line portion 423 of the linear body 420 of the shake preventing device 400 serves as a receiving portion. To prevent shaking. Therefore, the lower end portion of the magnetic recording disk substrate 10 does not shake in the out-of-plane direction, and does not shake around the axis line passing through the support position by the substrate supporter 300 vertically.

  The magnetic recording disk substrate 10 pulled up in this way is subjected to a heat treatment under predetermined conditions, and the lubricating layer 15 is fixed to the magnetic recording disk substrate 10.

(Main effects of this form)
As described above, in the present embodiment, when the magnetic recording disk substrate 10 is lifted from the chemical liquid 22, the linear body 420 of the shake preventing device 400 is formed at the lower ends of both surfaces of the magnetic recording disk substrate 10. Since the ridge line portion 423 is close as a receiving portion, the outer diameter dimension is small, for example, 1 inch, so that even the light magnetic recording disk substrate 10 is placed on the magnetic recording disk substrate 10 in the out-of-plane direction at the lower end. And the oscillation around the axis passing through the position supported by the substrate support 300 vertically does not occur. Therefore, even when the lubricating layer 15 is formed on the surface of the magnetic recording disk substrate 10 by the immersion film forming method, the uneven thickness of the lubricating layer 15 does not occur.

  Further, even when the specific gravity of the chemical liquid 22 is large, the magnetic recording disk substrate 10 is not greatly shaken, so that there is an advantage that the selection range of usable chemical liquids is widened. In this embodiment, a method of lowering the liquid level when performing the pulling-up operation is adopted. However, since the shake preventing tool 400 prevents the magnetic recording disk substrate 10 from shaking, Even when the magnetic recording disk substrate 10 is raised without lowering the liquid level, it is possible to avoid unevenness in the film thickness of the lubricating layer 15 due to shaking of the magnetic recording disk substrate 10.

  Further, in the present embodiment, since the present invention is applied to the formation of the lubricating layer 15, uneven thickness of the lubricating layer 15 does not hinder the flying distance of the magnetic head from being further shortened.

  Further, in this embodiment, since the shake preventing tools 400 are arranged in parallel on both sides sandwiching the position directly below the magnetic recording disk substrate 10, the lower end portion of the magnetic recording disk substrate 10 is swung in the out-of-plane direction. In addition to being able to reliably prevent, it is also possible to reliably prevent shaking around the axis passing through the position supported by the substrate support 300 vertically. In addition, it does not prevent the liquid pool preventing device 500 from being disposed between the shake preventing devices 400.

  Furthermore, in this embodiment, the magnetic recording disk substrate 10 is in contact with the linear body 420 when it is shaken, and the contact portion is extremely small. For this reason, a liquid pool does not occur at a portion where the magnetic recording disk substrate 10 and the linear body 420 are in contact with each other. Further, when the outer peripheral end portion 113 of the portion supported by the steady rest 400 comes out of the liquid surface of the chemical solution 22, the liquid droplets that are intended to accumulate on the outer peripheral end portion 113 are pulled toward the linear body 420 and become the outer periphery. It does not remain as a liquid pool at the end 113. Therefore, it is possible to reliably prevent a liquid pool from being formed at the outer peripheral end 113 of the magnetic recording disk substrate 10.

  Furthermore, in the substrate support 300, the inner peripheral end 112 of the magnetic recording disk substrate 10 contacts the support thread 320, and the contact portion is extremely small. For this reason, even when the chemical liquid 22 is held between the magnetic recording disk substrate 10 and the support yarn 320, no liquid pool is generated in the magnetic recording disk substrate 10. In addition, when the inner peripheral end 112 of the portion supported by the substrate support 300 comes out of the liquid surface of the chemical solution 22, the droplets that are to accumulate on the inner peripheral end 112 are pulled toward the support yarn 320. The liquid does not remain in the inner peripheral end 112 as a liquid pool. Therefore, it is possible to reliably prevent a liquid pool from being formed at the inner peripheral end 112 of the magnetic recording disk substrate 10.

(Other embodiments)
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the case where the lubricating layer 15 is formed on the surface of the magnetic recording disk substrate by the immersion film forming method has been described, but the present invention may be applied when the protective layer 14 is formed by the immersion film forming method. Good. Further, the present invention may be applied when a metal substrate is used as the nonmagnetic substrate 11 in addition to a glass substrate. Further, in the above embodiment, the shake prevention device 400 and the liquid pool removal device 500 are disposed at the lower position in the stage of the immersion operation with respect to the magnetic recording disk substrate. However, the lower side of the magnetic recording disk substrate 10 is only in the lifting operation. You may arrange | position the shake prevention tool 400 and the liquid pool removal tool 500 in a position.

(A), (b) is a top view which shows a magnetic recording disk, respectively, and a schematic sectional drawing of a magnetic recording disk. It is explanatory drawing which shows typically the structure of the immersion film-forming apparatus used for the immersion film-forming method which concerns on this invention. (A), (b) is an explanatory view when a state in which a plurality of magnetic recording disk substrates are mounted on the substrate processing tool used in the immersion film forming apparatus according to the present invention is viewed from the front, and from the side. It is explanatory drawing when seen. (A), (b) is respectively the side view and top view of a board | substrate support tool which were used for the immersion film-forming apparatus which concerns on this invention. (A), (b) is a side view of the support arm used for the board | substrate support shown in FIG. 4, respectively, and explanatory drawing which shows the tension | pulling method of the support thread | yarn to this support arm. (A), (b) is the side view and top view of a shake prevention tool which were used for the immersion film-forming apparatus based on this invention, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic recording disk 10 Magnetic recording disk substrate 11 Nonmagnetic substrate 12 Underlayer 13 Magnetic layer 14 Protective layer 15 Lubricating layer 100 Immersion film forming apparatus 200 Substrate processing tool 300 Substrate support tool 400 Shake prevention tool 410 Arm part 420 Linear body 421 Mountain part 422 Valley part 423 Ridge line part (receiving part)
425 Intersection 500 Liquid Pool Remover

Claims (7)

In a method for manufacturing a magnetic recording disk comprising an immersion film forming step of forming a lubricating layer by an immersion method on the surface of a magnetic recording disk substrate having a central hole,
In the immersion film forming step, the liquid surface of the chemical solution for forming the lubricating layer and the magnetic recording disk in a state where a plurality of magnetic recording disk substrates are supported by the substrate support inserted through the center hole. The substrate for magnetic recording is moved relative to the magnetic recording disk substrate, and the operation for dipping into the chemical solution and the pulling operation from the chemical solution are performed.
At least when performing the pulling-up operation, both the both sides of the magnetic recording disk substrate are provided with receiving portions provided on the arm portion that extends below the plurality of magnetic recording disk substrates in the shake preventing tool. Among the positions close to the lower end of the magnetic recording disk substrate in the out-of-plane direction of the magnetic recording disk substrate, on both sides sandwiching the position directly below the magnetic recording disk substrate, and
The method of manufacturing a magnetic recording disk, wherein the receiving portion is in a non-contact state with respect to the magnetic recording disk substrate .   2. The method of manufacturing a magnetic recording disk according to claim 1, wherein the magnetic recording disk substrate has an outer diameter of 2.5 inches or less. At the outer peripheral end of the magnetic recording disk substrate, the boundary between the outer peripheral end and both surfaces of the magnetic recording disk substrate is chamfered, and chamfered portions are formed on both sides of the outer peripheral wall surface,
The receiving portion is close to the boundary portion between the outer peripheral wall surface and the chamfered portion in the out-of-plane direction of the magnetic recording disk substrate among the lower end portions of both surfaces of the magnetic recording disk substrate. The method of manufacturing a magnetic recording disk according to claim 1, wherein: The anti-vibration device includes a linear body stretched on the arm portion so as to form a plurality of valleys at intersections along the longitudinal direction on the upper side of the arm portion,
The lower end of the magnetic recording disk substrate is located inside the valley of the linear body,
4. The ridge line portion sandwiching the valley portion on both sides of the linear body is close to the lower end portions of both surfaces of the magnetic recording disk substrate as the receiving portion. 5. A method for manufacturing a magnetic recording disk according to the item. The shake preventing device, due Rukoto a pair arranged in parallel on both sides sandwiching the position just below the substrate for the magnetic recording disk, wherein the receiving portion is disposed on both sides sandwiching the position just below the magnetic recording disk substrate,
At least when performing the pulling-up operation, the lower end portions of the plurality of magnetic recording disk substrates extend between the pair of shake prevention tools so as to pass directly under the plurality of magnetic recording disk substrates. 5. A method of manufacturing a magnetic recording disk according to claim 1 , wherein a liquid pool removing tool for removing the chemical solution from the substrate is disposed in a non-contact state with the magnetic recording disk substrate. . The substrate support includes a support arm extending so as to penetrate the center hole, and a plurality of valleys formed at intersections along the longitudinal direction of the support arm at an upper portion of the support arm. And a supporting thread stretched on
6. The magnetic recording disk substrate according to claim 1, wherein each of the plurality of magnetic recording disk substrates is supported in a state where an inner peripheral end portion of the center hole is floated from the support arm at the valley portion. A method for manufacturing a magnetic recording disk according to one item . 7. The magnetic recording disk substrate according to claim 1 , wherein when performing the lifting operation, the plurality of magnetic recording disk substrates are lifted from the liquid level by lowering the liquid level of the chemical liquid. 8. A method for manufacturing the magnetic recording disk as described.

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