JP6177603B2 - Grinding / polishing carrier and substrate manufacturing method - Google Patents

Description

  The present invention relates to a grinding / polishing carrier used for grinding or polishing a substrate and a method for producing the substrate.

  Conventionally, a glass substrate has been suitably used for a magnetic disk used as one of information recording media. Today, in response to a request for an increase in storage capacity in a hard disk drive device, the density of magnetic recording has been increased. Along with this, the magnetic recording information area is miniaturized by extremely shortening the flying distance from the magnetic recording surface of the magnetic head. It is preferable that the size and shape of the glass substrate used for such a magnetic disk be manufactured with high accuracy as intended.

In order to manufacture the glass substrate with high accuracy in size and shape, the surface of the glass substrate is ground and polished. In the processing of grinding and polishing a glass substrate, a plate-like grinding or polishing carrier for holding a glass substrate sandwiched between two surface plates and being ground or polished during grinding or polishing is used. The carrier is provided with a holding hole for holding the glass substrate.
Conventionally, a fiber reinforced resin obtained by impregnating a glass fiber or the like with a resin has been widely used as the carrier in terms of mechanical strength and cost. In particular, a carrier having a configuration in which a plurality of layers in which glass fiber is impregnated with an epoxy resin is laminated is preferably used. However, in this carrier, the glass substrate is ground or polished, and the carrier itself is worn with grinding or polishing. This wear is large in the case of grinding or polishing performed by providing fixed abrasive grains on the surface plate and supplying coolant between the glass plate and the fixed abrasive grains. For this reason, the carrier must be periodically replaced, which increases costs. In addition, there is a high possibility that fine particles such as resin detached from the carrier due to wear rub against the main surface of the glass substrate to form minute defects in the glass substrate. Furthermore, there is a high possibility that the fine particles such as the resin adhere firmly to the glass substrate and become a contamination source of the glass substrate.

  On the other hand, an object holding material that is difficult to adhere to the upper plate of the polishing apparatus and reduces defects of the object due to line trouble is known (Patent Document 1). Specifically, the workpiece holding material is a plate-like body obtained by heating and press-molding one sheet-like fiber base material impregnated with a thermosetting resin or a plurality of superposed sheets. And at least the surface layer of the plate-like body is composed of a sheet-like fiber base material impregnated with a fluororesin particle-containing thermosetting resin. As the thermosetting resin, phenol resin, epoxy resin, polyimide, or the like is used, and epoxy resin is particularly preferably used.

  Also, a carrier for polishing a silicon wafer is known in which a ring-shaped resin insert is disposed along the inner periphery of a holding hole of a carrier body (Patent Document 2). For example, an aramid resin is used as the resin insert.

JP 2002-103210 A JP 2010-30016 A

  However, the surface layer is ground or polished by using a non-abrasive holding material composed of a sheet-like fiber base material impregnated with a thermosetting resin containing fluororesin particles as a carrier and providing fixed abrasive grains on a surface plate. In this case, the wear rate of the carrier cannot be reduced and the life of the carrier cannot be extended for a carrier having a structure in which a plurality of layers in which glass fiber used in the past is impregnated with an epoxy resin is laminated. It was. Moreover, even if a carrier in which an aramid resin layer is formed not only on the inner peripheral portion of the holding hole of the carrier body but also on other portions, that is, on the entire surface of the carrier, an epoxy resin is used for the glass fiber used conventionally The life of the carrier could not be extended with respect to the carrier having a structure in which a plurality of layers impregnated with bismuth was laminated.

  Accordingly, the present invention provides a grinding or polishing carrier and a method for manufacturing a substrate using the carrier, which can reduce the wear rate and extend the life of the carrier in a grinding or polishing carrier. For the purpose.

The inventor of the present application has made extensive studies in order to solve the above-described conventional problems. As a result, coolant or polishing liquid is interposed between the carrier and the surface plate. It has been found that there is a difference in the wear rate depending on whether or not it easily sticks. That is, it has been found that the more difficult the carrier sticks to the surface plate, the less the friction between the carrier and the surface plate occurs, and as a result, the wear of the carrier is suppressed. It has also been found that reducing the affinity of the surface layer of the carrier for the coolant or the polishing liquid is effective for making the carrier difficult to stick to the surface plate. In general, since the solvent of the coolant and the polishing liquid is water, the carrier preferably has water repellency.
Furthermore, it has been found that when a resin layer is formed on the carrier surface, the frictional force between the surface plate and the carrier in the polishing or grinding apparatus differs depending on the material of the resin layer. And when using a thermoplastic resin for the carrier surface, it discovered that a frictional force became low compared with the case where a thermosetting resin is used.
Based on the above findings, the present inventors have found the following invention.

That is, one embodiment of the present invention is a grinding / polishing carrier having a holding hole for holding a substrate,
The main surface of the grinding / polishing carrier is formed of a resin layer of a thermoplastic resin containing a fluororesin ,
The thermoplastic resin is at least one selected from the group consisting of polyamide, thermoplastic polyimide, polyamideimide, polyacetal, aromatic polyether ketone, amorphous polyarylate, polystyrene, polybutylene naphthalate, and ultrahigh molecular weight polyethylene. It is a carrier for grinding / polishing characterized by the above-mentioned resin .

Another aspect of the present invention is also a grinding / polishing carrier having a holding hole for holding a substrate, wherein the main surface of the grinding / polishing carrier is a heat in which fluorine is introduced into a resin skeleton. A grinding / polishing carrier characterized in that it is formed of a resin layer comprising a plastic resin composition.

  In the carrier according to the two aspects, the thickness of the resin layer is preferably 0.1% or more of the total thickness of the carrier for grinding / polishing. The thickness of the resin layer is preferably 50% or less of the total thickness of the grinding / polishing carrier.

  The contact angle of the resin layer with respect to the coolant or polishing liquid used during grinding or polishing is preferably 30 degrees or more.

  The thermoplastic resin is preferably at least one resin selected from the group consisting of polyamide, thermoplastic polyimide, polyamideimide, and ultrahigh molecular weight polyethylene.

  The grinding / polishing carrier has the resin layer formed on a base material, and the base material is formed by laminating one or more sheet-like fiber base materials impregnated with a resin, The fiber of the material is at least one selected from the group consisting of glass fiber, carbon fiber, aramid fiber, polyethylene fiber, polypropylene fiber, polyparaphenylene benzobisoxazole fiber, liquid crystal polymer fiber, hemp fiber, bagasse fiber, talc fiber It is preferable that the fiber is.

Furthermore, another aspect of the present invention is a method for manufacturing a substrate. In this method, the grinding / polishing carrier and the grinding or polishing apparatus provided with two surface plates are used , and the substrate is sandwiched between the two surface plates to grind or polish the main surface of the substrate. Including processing.

  In the treatment, it is preferable that grinding or polishing is performed with fixed abrasive grains provided on the surface of the surface plate.

The pressure at which the surface plate presses the glass substrate during the treatment is preferably 10 to 200 g / cm ² .
The substrate manufacturing method preferably uses a glass substrate for a magnetic disk as the substrate.

  In the above-described grinding or polishing carrier and the substrate manufacturing method using this carrier, the wear rate can be reduced and the life of the carrier can be extended.

It is a disassembled perspective view of an example of the grinding device (double-side polish apparatus) using the carrier of this embodiment. It is sectional drawing of an example of the grinding apparatus shown in FIG. It is sectional drawing of an example of the carrier of this embodiment.

  Hereinafter, the grinding / polishing carrier and substrate manufacturing method of the present invention will be described in detail.

[Grinding device / Polishing device]
A glass substrate grinding apparatus and polishing apparatus using the carrier of this embodiment will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a grinding apparatus (double-side polishing apparatus). FIG. 2 is a sectional view of the grinding apparatus. Since the polishing apparatus has the same configuration as the polishing apparatus, description of the polishing apparatus is omitted.

  As shown in FIG. 1, the grinding apparatus has a pair of upper and lower surface plates, that is, an upper surface plate 40 and a lower surface plate 60. An annular glass substrate G is held between the upper surface plate 40 and the lower surface plate 60, and either one or both of the upper surface plate 40 and the lower surface plate 60 are moved to operate the glass substrate G and each By moving the surface plate relative to each other, both main surfaces of the glass substrate G can be ground. A grinding fluid (coolant) is supplied between the glass substrate and the surface plate. Hereinafter, when the upper surface plate 40 and the lower surface plate 60 are collectively described, they are simply referred to as a surface plate.

The configuration of the grinding apparatus will be described more specifically with reference to FIGS. 1 and 2.
In the grinding apparatus, a large number of fixed abrasive grains 10 are attached to the upper surface of the lower surface plate 60 and the bottom surface of the upper surface plate 40. In FIG. 1, a large number of fixed abrasive grains 10 are shown in a sheet shape for convenience. As the fixed abrasive 10, for example, diamond particles hardened with a resin can be used.
The carrier 30 has a holding hole for holding the glass substrate G when the disk-shaped glass substrate G is sandwiched between two surface plates and the main surface of the glass substrate G is ground. Specifically, the carrier 30 includes a tooth portion 31 provided on the outer peripheral portion and meshing with the sun gear 61 and the internal gear 62, and one or a plurality of holding holes 32 for receiving and holding the glass substrate G. . The sun gear 61, the internal gear 62 provided on the outer edge, and the disk-shaped carrier 30 constitute a planetary gear mechanism centered on the central axis CTR as a whole. The disc-shaped carrier 30 meshes with the sun gear 61 on the inner peripheral side and meshes with the internal gear 62 on the outer peripheral side, and accommodates and holds one or more glass substrates G (workpieces). On the lower surface plate 60, the carrier 30 revolves while rotating as a planetary gear, and the glass substrate G and the lower surface plate 60 are relatively moved. For example, if the sun gear 61 rotates in the CCW (counterclockwise) direction, the carrier 30 rotates in the CW (clockwise) direction, and the internal gear 62 rotates in the CCW direction. As a result, a relative motion occurs between the lower surface plate 60 and the glass substrate G. Similarly, the glass substrate G and the upper surface plate 40 may be moved relatively.

  During the operation of the relative movement, the upper surface plate 40 is pressed against the glass substrate G held by the carrier 30 (that is, in the vertical direction) with a predetermined pressure, whereby the fixed abrasive is applied to the glass substrate G. The grain 10 is pressed. Further, as shown in FIG. 2, coolant is supplied between the glass substrate G and the fixed abrasive grains 10 from a supply tank 71 via one or a plurality of pipes 72 by a pump (not shown).

Although the thickness of the carrier 30 is smaller than the thickness of the glass plate G, the present inventor has found that the carrier 30 is worn by rubbing against the upper surface plate 40 or the lower surface plate 60.
The reason is considered as follows. That is, since the coolant exists between the carrier and the surface plate, the carrier generally tends to stick to the surface plate. Further, since the carrier is thinner than the glass substrate that is the workpiece, it is easy to bend. In such a state, if the carrier is caused to rotate by an external force applied from the sun gear 61 and the internal gear 62, the carrier partially undulates and easily comes into contact with the upper surface plate 40 or the lower surface plate 60. It is considered that the carrier and the surface plate are worn by rubbing. In addition, it is considered that the more easily the carrier is attached to the surface plate, the stronger the frictional force and the more the wear becomes.

For this reason, the carrier 30 of this embodiment is difficult to stick to the upper surface plate 40 or the lower surface plate 60. Even if the carrier 30 sticks to the upper surface plate 40 or the lower surface plate 60, the attached portion Is desired to be easily released, and further, it is difficult to be worn even if the upper surface plate 40 or the lower surface plate 60 contacts and rubs.
Therefore, each of the main surfaces on both sides of the carrier 30 is covered with a resin layer made of a thermoplastic resin composition in which fluorine is introduced into the skeleton of the thermoplastic resin. Or each of the main surface of the both sides of the carrier 30 is covered with the resin layer of the thermoplastic resin containing a fluororesin. The introduction of fluorine into the skeleton of the above-described thermoplastic resin includes introduction of fluorine into a main chain portion of the resin or a side chain portion derived from the main chain.

  FIG. 3 is a cross-sectional view of the carrier 30. The carrier 30 consists of five layers, and the layers on both sides are resin layers 30a. That is, as for the carrier 30, the resin layer 30a is formed in the surface of the both sides of a base material. The resin layer 30a is a layer made of a thermoplastic resin composition in which fluorine is introduced into a skeleton of a thermoplastic resin, or a layer of a thermoplastic resin containing a fluororesin. The inner three layers sandwiched between the resin layers 30a are base material layers 30b. The base material is formed by laminating three layers of a sheet-like fiber base material impregnated with a resin. The base material of this embodiment is configured by laminating three base material layers 30b. The base material layer 30b is composed of one layer, two layers, four layers, five layers, six layers, seven layers, or the like. There may be.

Here, since the coultant used for grinding is an aqueous solution using water as a solvent, the resin layer 30a on the surface of the carrier 30 has water repellency. For this reason, since the microdroplets that have been agglomerated and rounded are uniformly distributed between the carrier 30 and the fixed abrasive grains 10, the carrier 30 is less likely to stick to the upper surface plate 40 or the lower surface plate 60. Even if the carrier 30 is stuck to the upper surface plate 40 or the lower surface plate 60, the area of the adhered portion is small, and since micro droplets are interposed around the area, the carrier 30 is easily released. For this reason, the wear of the carrier 40 is reduced. The contact angle of the resin layer 30a with respect to the coolant (or polishing liquid) during grinding is preferably 30 degrees or more from the viewpoint of exhibiting water repellency.
For the resin layer 30a of the carrier 30 of the present embodiment, a thermoplastic resin composition or a thermoplastic resin in which fluorine is introduced into the resin skeleton is used. Thereby, as can be seen from the examples and comparative examples described later, the carrier 30 has superior wear resistance compared to the case where a thermosetting resin composition or a thermosetting resin in which fluorine is introduced into the resin skeleton is used. Demonstrate. The reason is considered as follows. The surface plate and the carrier are locally contacted as described above during the grinding of the glass substrate to generate frictional heat. In the case of this embodiment using a thermoplastic resin for the resin layer 30a, the formation of the resin layer 30a is performed. Even after the surface, the surface of the resin layer 30a becomes plastic due to the locally generated frictional heat, and the plasticized portion is slightly deformed with respect to the generated frictional force to disperse the frictional force. . On the other hand, since the thermosetting resin is cured, a frictional force that prevents the movement of the carrier 30 is generated. For this reason, the amount of wear in the carrier 30 is reduced when the thermoplastic resin is used compared to when the thermosetting resin is used.

The thermoplastic resin used for the resin layer 30a of the carrier 30 is polyamide, thermoplastic polyimide, polyamideimide, polyacetal, aromatic polyetherketone, amorphous polyarylate, polystyrene, polyphenylene sulfide, polybutylene naphthalate, and ultra high polymer. The at least one resin selected from the group consisting of polyethylene is preferable from the viewpoint of reducing the frictional force described above. Among these, polyamide, thermoplastic polyimide, polyamideimide, or ultrahigh molecular weight polyethylene resin is preferably used, and in particular, polyamide or polyamideimide resin is preferably used. Among these, an aramid resin having wear resistance is optimally used as the thermoplastic resin.
Examples of the thermoplastic resin composition into which fluorine is introduced include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, polyvinylidene fluoride, PFA (tetrafluoroethylene (C ₂ F ₄ ), perfluoroalkoxyethylene, Copolymer), ETFE (copolymer of tetrafluoroethylene (C ₂ F ₄ ) and ethylene (C ₂ H ₄ )), etc. Among them, use of polytetrafluoroethylene is a coolant or polishing liquid. It is preferable in that it is not compatible with.
Examples of the fluororesin contained in the thermoplastic resin include polytetrafluoroethylene, perfluoroalkoxy fluororesin, PFA, ETFE and the like. In particular, polytetrafluoroethylene is preferably used in terms of imparting water repellency. In addition, it is preferable that content of a fluororesin shall be 1-20 wt%.
Further, the fibers of the fiber base material in the base material layer 30b are glass fiber, carbon fiber, aramid fiber, polyethylene fiber, polypropylene fiber, polyparaphenylene benzobisoxazole fiber, liquid crystal polymer fiber, hemp fiber, bagasse fiber, talc fiber. It is preferable that at least one kind of fiber selected from the group consisting of the above group is used in order to ensure mechanical strength without damaging the carrier 30. Among these, glass fiber, carbon fiber, aramid fiber, or polyethylene fiber can be preferably used. Particularly preferably, glass fiber or aramid fiber can be used. Examples of the resin used for the base material layer 30b include an epoxy resin, an aramid resin, and a phenol resin. Among these, it is preferable to use an aramid resin in terms of securing rigidity.

  The thickness of the resin layer 30a is preferably 0.1% or more of the total thickness of the carrier 30. In addition, the thickness of the resin layer 30 a is preferably 50% or less of the total thickness of the carrier 30. When the thickness of the resin layer 30a is less than 0.1% of the total thickness of the carrier 30, the mechanical strength of the carrier 30 is improved. However, since the thickness of the resin layer 30a is thin, the carrier 30 is caused by wear. The lifetime that can be used may be shortened. When the thickness of the resin layer 30a is larger than 50% of the total thickness of the carrier 30, the thickness of the base material layer 30b is reduced, and the mechanical strength of the carrier 30 may be reduced.

1 and 2, the fixed abrasive is provided on the upper surface plate 40 or the lower surface plate 60. A polishing pad is attached to the upper surface plate 40 or the lower surface plate 60, and the glass substrate G and A slurry made of an aqueous solution containing abrasive grains or the like and containing water as a solvent may be supplied between the upper surface plate 40 and the lower surface plate 60. The carrier 30 can also be used in a polishing apparatus that polishes the glass substrate G in addition to the grinding apparatus.
The grinding device using such a carrier 30 can be suitably used for manufacturing a glass substrate for a magnetic disk as shown below by using it in a polishing device having a configuration substantially similar to that of this grinding device. When used in a polishing apparatus, a polishing pad is attached to the upper surface plate 40 or the lower surface plate 60 instead of fixed abrasive grains. Further, a polishing liquid (slurry) containing abrasive grains is used instead of the coolant.

(Description of manufacturing method of glass substrate for magnetic disk)
In the manufacturing method of the present embodiment, first, a glass blank that is a material for a plate-shaped magnetic disk glass substrate having a pair of main surfaces is formed. Next, the rough grinding process of this glass blank is performed. Thereafter, the glass blank is subjected to a shape processing treatment and an end surface polishing treatment. Then, the precise grinding process which uses a fixed abrasive for the glass substrate obtained from the glass blank is performed. Thereafter, a first polishing process, a chemical strengthening process, and a second polishing process are performed on the glass substrate. In the present embodiment, the above process is performed. However, the above process is not necessarily performed, and these processes may not be appropriately performed. Hereinafter, each process will be described.

(A) Glass blank molding process In the molding of a glass blank, for example, a press molding method can be used. A circular glass blank can be obtained by the press molding method. Furthermore, it can manufacture using well-known manufacturing methods, such as a downdraw method, a redraw method, and a fusion method. A disk-shaped glass substrate serving as a base of the magnetic disk glass substrate can be obtained by appropriately performing shape processing on the plate-shaped glass blanks produced by these known production methods.

(B) Rough grinding treatment In the rough grinding treatment, specifically, the glass blank is held on both sides of the glass blank while being held in holding holes provided in a holding member (carrier) mounted on a well-known double-side grinding apparatus. The main surface is ground. At this time, the carrier described above may be used. For example, loose abrasive grains are used as the abrasive. In the rough grinding process, the glass blank is ground so as to approximate the target plate thickness dimension and the flatness of the main surface. The rough grinding process is performed according to the dimensional accuracy or surface roughness of the molded glass blank, and may not be performed depending on the case.

(C) Shape processing processing Next, shape processing processing is performed. In the shape processing, after forming the glass blank, a circular hole is formed using a known processing method to obtain a disk-shaped glass substrate having a circular hole. Thereafter, the end surface of the glass substrate is chamfered. Thereby, a side wall surface orthogonal to the main surface and a chamfered surface (intervening surface) connecting the side wall surface and the main surface are formed on the end surface of the glass substrate.

(D) End surface polishing treatment Next, an end surface polishing treatment of the glass substrate is performed. The end surface polishing process is a process for performing polishing by supplying a polishing liquid containing loose abrasive grains between the polishing brush and the end surface of the glass substrate and relatively moving the polishing brush and the glass substrate. In the end surface polishing, the inner peripheral side end surface and the outer peripheral side end surface of the glass substrate are to be polished, and the inner peripheral side end surface and the outer peripheral side end surface are in a mirror state.

(E) Fine grinding process Next, a fine grinding process is performed on the main surface of the glass substrate. Specifically, grinding is performed on the main surface of the glass substrate using a double-side grinding apparatus shown in FIGS. Specifically, the main surfaces on both sides of the glass substrate are ground while holding the glass substrate in the holding hole 32 provided in the carrier 30 which is a holding member of the double-side grinding apparatus. The machining allowance by grinding is, for example, about 10 μm to 200 μm. At this time, the pressure with which the upper surface plate 40 or the lower surface plate 60 presses the glass substrate G is preferably 10 to 200 g / cm ² from the viewpoint of effective grinding. The double-sided grinding apparatus has a pair of upper and lower surface plates (upper surface plate and lower surface plate), and fixed abrasive grains containing, for example, diamond abrasive particles are attached to the surfaces of the upper surface plate and the lower surface plate. As the abrasive grains, for example, abrasive grains having an average particle diameter of 5 μm to 50 μm are used. Note that as the abrasive grains, particles such as diamond or an aggregate obtained by solidifying a plurality of particles with a binder such as glass, ceramic, metal, or resin can be used. And, for example, a fixed abrasive can be obtained by sticking a pellet obtained by fixing these abrasive grains using a support material such as a resin to a sheet. The glass substrate is sandwiched between the upper surface plate and the lower surface plate. Then, while supplying the coolant, by moving either the upper surface plate or the lower surface plate, or both, the glass substrate and each surface plate are moved relatively to each other. The main surface can be ground.
In the grinding process of the present embodiment, the grinding surface containing the fixed abrasive and the main surface of the glass substrate are brought into contact with each other to grind the main surface of the glass substrate. However, grinding using loose abrasive grains may be performed.

(F) First polishing treatment Next, a first polishing treatment is performed on the main surface of the glass substrate. Specifically, polishing of the main surfaces on both sides of the glass substrate while holding the outer peripheral side end surface of the glass substrate in a holding hole provided in the carrier of the double-side polishing apparatus having the same configuration as the above-described double-side grinding apparatus including the carrier Is done. The first polishing process uses a polishing pad attached to a surface plate using loose abrasive grains. In the first polishing, for example, cracks and distortions remaining on the main surface when grinding with fixed abrasive grains is performed, or minute surface irregularities generated on the main surface by crystallization treatment are removed. By making the machining allowance within the above range, it is possible to reduce the surface roughness of the main surface, for example, the arithmetic average roughness Ra, while preventing the shape of the end portion of the main surface from excessively dropping or protruding. .
The free abrasive grains used for the first polishing are not particularly limited. For example, cerium oxide abrasive grains or zirconia abrasive grains are used.
Although the kind in particular of a polishing pad is not restrict | limited, For example, a hard foaming urethane resin polisher is used.

(G) Chemical strengthening treatment The glass substrate can be appropriately chemically strengthened. As the chemical strengthening liquid, for example, a molten liquid obtained by heating potassium nitrate, sodium nitrate, or a mixture thereof can be used. Then, by immersing the glass substrate in the chemical strengthening solution, lithium ions and sodium ions in the glass composition on the surface of the glass substrate are converted into sodium ions and potassium ions having relatively large ion radii in the chemical strengthening solution, respectively. By replacing each, a compressive stress layer is formed in the surface layer portion, and the glass substrate is strengthened.
The timing of performing the chemical strengthening treatment can be determined as appropriate. However, if the polishing treatment is performed after the chemical strengthening treatment, the foreign matter fixed to the surface of the glass substrate by the chemical strengthening treatment can be removed together with the smoothing of the surface. This is particularly preferable because it can be performed. Further, the chemical strengthening treatment may be performed as necessary, and may not be performed.

(H) Second polishing (mirror polishing) treatment Next, the glass substrate after the chemical strengthening treatment is subjected to second polishing. The second polishing is intended for mirror polishing of the main surface. Also in the second polishing, a double-side polishing apparatus having the same configuration as the double-side polishing apparatus used for the first polishing is used. By doing so, it is possible to reduce the roughness of the main surface while preventing the shape of the end portion of the main surface from excessively dropping or protruding. The second polishing process is different from the first polishing process in that the kind of loose abrasive grains is different and the particle size is reduced, and the hardness of the resin polisher of the polishing pad is softened.

As the free abrasive grains used for the second polishing treatment, for example, fine particles such as colloidal silica are used. By cleaning the polished glass substrate, a glass substrate for a magnetic disk can be obtained.
The second polishing process is not necessarily an essential process, but it is preferable that the second polishing process is performed in that the level of surface irregularities on the main surface of the glass substrate can be further improved. Thus, the glass substrate subjected to the second polishing becomes a glass substrate for a magnetic disk.

  Thus, each of the main surfaces on both sides of the carrier in the present embodiment is a resin layer made of a thermoplastic resin composition in which fluorine is introduced into the skeleton of the thermoplastic resin, or a thermoplastic resin containing a fluororesin. Covered with a resin layer. In addition, since the coolant or polishing liquid used for grinding or polishing is an aqueous solution using water as a solvent, the resin layer on the surface of the carrier has water repellency. For this reason, since the fine droplets which are aggregated and rounded are uniformly distributed between the upper surface plate and the lower surface plate and the carrier, the carrier hardly adheres to the upper surface plate or the lower surface plate. Even if the carrier sticks to the upper surface plate or the lower surface plate, the area of the attached portion is small, and since micro droplets are present around the area, the carrier is easily released. For this reason, the wear of the carrier is reduced. In addition, since a thermoplastic resin is used for the resin layer, the surface of the resin layer is in a plastic state due to local frictional heat even after the resin layer is formed. The frictional force is dispersed by minute deformation with respect to the generated frictional force, and the frictional force does not hinder the movement of the carrier. On the other hand, since the thermosetting resin is cured, it generates a frictional force that hinders the movement of the carrier. For this reason, the wear in the carrier is reduced when the thermoplastic resin is used compared to when the thermosetting resin is used.

[Examples, conventional examples, comparative examples]
In order to confirm the effect of this embodiment, various carriers were produced and the amount of wear of the carriers was examined. The glass substrate for magnetic disk to be processed was a glass substrate having a size of 2.5 inches and a thickness of 0.8 mm.
Using the carrier shown in Table 1 below, the above-described (e) fine grinding treatment was performed. The base material layer of the carrier was 5 layers as a whole. When two resin layers were formed as upper and lower surface layers, the base material layer was 3 layers, and when there was no surface layer, the base material layer was 5 layers. In any carrier, the thickness per layer was 0.1 mm, and the total thickness was 0.5 mm. In Example 1 and the comparative example, the content of the fluororesin was 10 wt%.
The amount of abrasion was measured after the glass substrate was ground a predetermined number of times. The amount of carrier wear was determined by measuring the thickness of the carrier at two locations, the center and the outer periphery of the carrier, and subtracting the average value from the thickness of the carrier when it was new (unused).
In the fine grinding process, fixed abrasive grains in which diamond particles are hardened with resin are provided on the upper surface plate 40 and the lower surface plate 60, and the load is set so that the pressure for pressing the glass substrate is 150 g / cm ^2. Went.

  Based on the wear amount of the carrier of Conventional Example 2, the wear amount of each example was indexed (relative comparison). Table 2 below shows the results of the amount of wear.

From Table 2, it can be seen that the amount of wear in Example 1 is superior to Conventional Example 2 and Comparative Example. In the comparative example and the conventional example 1, abnormal noise was generated in the carrier during the precision grinding process, and there was a problem that it could not be used for a long time.
Thus, the carrier of this embodiment can reduce the amount of wear and extend the lifetime of the carrier. For this reason, the manufacturing cost in the glass substrate for magnetic discs can be held down. In addition, since the carrier according to the present embodiment has water repellency, it becomes difficult for the carrier to stick to the surface plate due to liquid droplets. For example, the glass substrate sticks to the upper surface plate as the carrier adheres to the upper surface plate. Can be prevented. For this reason, after grinding or polishing is completed, it is possible to suppress the carrier attached to the upper surface plate from dropping downward and creating defective defects such as scratches on the main surface of the glass substrate.

  As described above, the grinding / polishing carrier and the substrate manufacturing method of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments and examples, and various improvements and modifications can be made without departing from the spirit of the present invention. Of course, changes may be made.

DESCRIPTION OF SYMBOLS 10 Fixed abrasive 30 Carrier 31 Teeth part 32 Holding hole 40 Upper surface plate 60 Lower surface plate 61 Sun gear 62 Internal gear 71 Supply tank 72 Piping

Claims (9)

A grinding / polishing carrier having a holding hole for holding a substrate,
The main surface of the grinding / polishing carrier is formed of a resin layer of a thermoplastic resin containing a fluororesin ,
The thermoplastic resin is at least one selected from the group consisting of polyamide, thermoplastic polyimide, polyamideimide, polyacetal, aromatic polyether ketone, amorphous polyarylate, polystyrene, polybutylene naphthalate, and ultrahigh molecular weight polyethylene. A grinding / polishing carrier characterized in that it is a resin . The thickness of the resin layer, wherein at grinding / or 0.1% of the total thickness of the polishing carrier, grinding / polishing carrier according to claim 1. The grinding / polishing carrier according to claim 1 or 2 , wherein a contact angle of the resin layer with respect to a coolant or a polishing liquid used during grinding or polishing is 30 degrees or more. The grinding / polishing carrier has the resin layer formed on a substrate,
The base material is constituted by laminating one or more layers of a sheet-like fiber base material impregnated with a resin,
The fiber base fiber is selected from the group consisting of glass fiber, carbon fiber, aramid fiber, polyethylene fiber, polypropylene fiber, polyparaphenylene benzobisoxazole fiber, liquid crystal polymer fiber, hemp fiber, bagasse fiber, talc fiber The carrier for grinding / polishing according to any one of claims 1 to 3 , wherein the carrier is at least one kind of fiber. The grinding / polishing of any one of claims 1 to 4, wherein the thermoplastic resin is at least one resin selected from the group consisting of polyamide, thermoplastic polyimide, polyamideimide, and ultra-high molecular weight polyethylene. Polishing carrier. A method for manufacturing a substrate, comprising:
Using the grinding / polishing carrier according to any one of claims 1 to 5 and a grinding or polishing apparatus including two surface plates, the substrate is sandwiched between the two surface plates. A method for manufacturing a substrate, comprising a process of grinding or polishing a main surface. The method for manufacturing a substrate according to claim 6 , wherein in the treatment, grinding or polishing is performed with fixed abrasive grains provided on a surface of the surface plate. The pressure which the surface plate during the process presses the substrate is 10 to 200 g / cm ^2, substrate manufacturing method according to claim 6 or 7. The method of manufacturing a substrate according to any one of claims 6-8, method of manufacturing a substrate, which comprises using the glass substrate for magnetic disks as the substrate.

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