TWI707746B - Abrasive material - Google Patents

Abstract

The present invention is to provide an abrasive material whose polishing efficiency is not easily reduced and the polishing cost is relatively low. The abrasive includes a substrate and a polishing layer that is laminated on the surface of the substrate and contains abrasive grains and a binder. The polishing layer has a plurality of polishing portions divided by grooves on the surface, and has multiple polishing portions along the polishing direction. In the multiple types of regions with different occupied area ratios of the polishing portions, the difference in the occupied area ratios of the plurality of polishing portions in a pair of regions adjacent to each other along the polishing direction is 3% or more and 21% or less. Each area may have a size that can include a circle with a diameter of 5 cm when viewed from above. Among a pair of regions adjacent to each other along the polishing direction, the occupied area ratio of the plurality of polishing portions in one region is preferably 4.5% or more and 9% or less, and the occupied area ratio of the plurality of polishing portions in the other region is more preferable It is 9% or more and 16% or less.

Description

Abrasive material

The present invention relates to an abrasive material.

In recent years, electronic devices such as hard disks have become more sophisticated. As a substrate material for such electronic devices, in consideration of rigidity, impact resistance, and heat resistance that can cope with miniaturization or thinning, glass is often used. The glass substrate is a brittle material, and its mechanical strength is obviously damaged due to surface damage. Therefore, the polishing of such a substrate requires a polishing rate and flattening accuracy with less damage.

Generally, if it is desired to increase the flattening accuracy of finishing machining, the processing time tends to be prolonged, and the polishing rate and flattening accuracy are in a trade-off relationship. Therefore, it is difficult to achieve both polishing rate and flattening accuracy. In contrast to this, there has been proposed an abrasive having a polishing portion in which abrasive grains and fillers are dispersed in order to have both polishing rate and flattening accuracy (see Japanese Patent Application Publication No. 2002-542057).

However, if such a conventional polishing material is polished for a certain period of time, the polishing rate decreases due to passivation of abrasive grains or clogging of the surface of the polishing layer. In order to reproduce the reduced polishing rate, it is necessary to perform a so-called dress in which the surface of the abrasive material is polished off and a new surface appears on the surface. Before and after the dressing, the polishing material is also required to be cleaned, and the dressing is an operation that takes time. During the dressing, the polishing of the glass substrate as the object to be polished is interrupted. Therefore, the previous polishing material has a large reduction in polishing efficiency due to the dressing.

In addition, in recent years, for light-emitting diodes (LEDs) or power devices, there is an increasing demand for hard and brittle, chemically stable substrates such as sapphire or silicon carbide. For such difficult-to-process substrates, a more efficient polishing method is required compared to the established polishing of silicon substrates. Furthermore, since such a substrate is chemically stable, it takes time for chemical mechanical polishing (CMP) processing in the final step of polishing. Therefore, it is necessary to reduce the roughness or damage of the substrate surface as much as possible in the polishing as the previous step, and shorten the processing time of CMP. Therefore, high polishing accuracy is required for polishing in the previous step of CMP.

Regarding the method of polishing the difficult-to-process substrate, for example, free abrasive grain polishing using diamond slurry and abrasive material has been proposed (refer to Japanese Patent Laid-Open No. 2014-100766), or keeping free abrasive grains on the surface of the abrasive material. The semi-fixed abrasive grain is polished in the hole of the hole (refer to Japanese Patent Laid-Open No. 2002-86350).

The conventional free abrasive grain polishing and semi-fixed abrasive grain polishing realize efficient polishing by using diamond for the abrasive grains. However, in the prior free abrasive grain polishing and semi-fixed abrasive grain polishing, the abrasive grains must be continuously supplied to the abrasive, and the polishing cost is high.

[Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2002-542057

[Patent Document 2] Japanese Patent Laid-Open No. 2014-100766

[Patent Document 3] Japanese Patent Laid-Open No. 2002-86350

The present invention is made in view of such disadvantages, and its object is to provide a polishing material with high polishing accuracy, low polishing efficiency, and relatively low polishing cost.

The invention made in order to solve the above-mentioned problems is an abrasive including a substrate and an abrasive layer laminated on the surface side of the substrate and containing abrasive grains and a binder, and the abrasive is characterized by: The polishing layer is provided with a plurality of polishing portions divided by grooves on the surface thereof, and has a plurality of types of regions with different occupation area ratios of the plurality of polishing portions along the polishing direction, and a pair of adjacent ones along the polishing direction The difference in the occupied area ratio of the plurality of polishing parts in the region is 3% or more and 21% or less.

For this polishing material, the difference in the occupied area ratio of the plurality of polishing portions of a pair of the regions adjacent to the polishing direction is within the above range. Therefore, in the polishing material, the area with a small occupied area is subjected to a moderately large polishing pressure during polishing. Due to the difference in the polishing pressure, the area with a small occupied area is worn first, so the polishing material produces a moderate step difference between adjacent areas. Therefore, during polishing, polishing is performed while moving the object to be polished from a region with a small height to a region with a large height, or in the opposite direction. The grip force of the abrasive material increases due to the spanning resistance when moving between the regions, and the surface pressure is further increased in the regions where the height is large, that is, the occupied area ratio is large. Thereby, the polishing material can more effectively apply the surface pressure during polishing, so it has high polishing Speed and flattening accuracy, and the grinding rate is not easy to decrease in a relatively long period of time due to the gripping force. Therefore, the polishing material does not need to be frequently trimmed, so that the running cost can be reduced or the step management can be simplified, and the polishing accuracy and polishing efficiency are excellent. Furthermore, there is no need to newly supply abrasive grains during polishing, so polishing using this abrasive material has lower polishing costs than polishing using free abrasive grains.

Each of the regions may have a size that may include a circle with a diameter of 5 cm in a plan view. In this way, by setting the respective regions to a size that can include a circle with a diameter of 5 cm in a plan view, the gripping force increase effect due to the span resistance can be obtained more reliably.

In a pair of regions adjacent to each other in the polishing direction, the occupied area ratio of the plurality of polishing portions in one region is preferably 4.5% or more and 9% or less. In addition, the occupied area ratio of the plurality of polishing portions in the other region is preferably 9% or more and 16% or less. By setting the occupied area ratio of the pair of regions adjacent to each other in the polishing direction within the above-mentioned range, the polishing layer can be hardly worn, and a moderate step difference can be generated between the adjacent regions. Therefore, the durability of the polishing layer is maintained, and the gripping force increase effect due to the span resistance can be obtained more reliably.

The abrasive particles may be diamond abrasive particles. By setting the abrasive grains as diamond abrasive grains in this way, the polishing force can be increased, so the surface pressure during polishing can be applied more effectively, and the gripping force increase effect due to the span resistance can be obtained more reliably.

The main component of the adhesive may be an inorganic substance. By setting the main component of the binder as an inorganic substance in this way, the retention of abrasive grains can be improved, and the abrasive grains can be prevented from falling off. Therefore, the polishing rate is less likely to decrease.

The adhesive may contain a filler mainly composed of oxides. By In this way, the filler containing oxides as the main component in the adhesive can increase the elastic coefficient of the adhesive, so it is easy to control the wear of the abrasive layer. Therefore, a moderate step difference is likely to occur between adjacent regions of the polishing material during polishing, so that the effect of increasing the gripping force by the span resistance can be obtained more reliably.

Therefore, the polishing material can be preferably used for flat polishing of substrates typified by glass substrates.

Here, the "area" of the polishing layer refers to the area where the deviation of the area of each polishing portion and the deviation of the groove width are within 3%. In addition, the "width of the groove" refers to the shortest distance between a pair of adjacent polishing portions.

In addition, the term "main component" refers to a component with the largest content, for example, a component with a content of 50% by mass or more.

As explained above, the polishing material of the present invention has excellent polishing accuracy, is not easy to decrease in polishing efficiency, and has low polishing cost. Therefore, the abrasive can be preferably used for the polishing of glass substrates used in electronic devices, or difficult-to-process substrates such as sapphire or silicon carbide.

1, 2: Abrasive material

10, 11: substrate

20: Grinding layer

21: Abrasive grain

22: Adhesive

23: Slot

24: Grinding Department

30: Next layer

40: Support

41: Adhesive layer of support

X1: Zone 1

X2: Zone 2

X3: Zone 3

X4: Area 4

Fig. 1A is a schematic plan view showing an abrasive material according to an embodiment of the present invention.

Fig. 1B is a schematic cross-sectional view taken along the line A-A of the abrasive material of Fig. 1A.

Fig. 2 is a schematic cross-sectional view showing an abrasive material of an embodiment different from Fig. 1B.

[First Embodiment]

Hereinafter, the first embodiment of the present invention will be described in detail while appropriately referring to the drawings.

<Abrasive material>

The polishing material 1 shown in FIGS. 1A and 1B has a disc shape and mainly includes a base 10 and a polishing layer 20 laminated on the surface side of the base 10. In addition, the polishing material 1 includes an adhesive layer 30 laminated on the back side of the base material 10. The polishing material 1 is placed on a polishing platen of a well-known polishing device, and the polishing device is rotated while contacting the object to be polished to perform polishing. That is, the polishing direction of the polishing material 1 is the circumferential direction of the base 10.

(Substrate)

The substrate 10 is a plate-shaped member for supporting the polishing layer 20.

The material of the substrate 10 is not particularly limited, and examples include: polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polyimide (Polyimide, PI), polyethylene naphthalate (PEN), aromatic polyamide (aramide), aluminum, copper, etc. Among them, aluminum having good adhesion to the polishing layer 20 is preferred. In addition, the surface of the substrate 10 may be subjected to treatments to improve adhesiveness, such as chemical treatment, corona treatment, primer treatment, and the like.

In addition, the substrate 10 may have flexibility or ductility. Because the substrate 10 has flexibility or ductility in this way, the abrasive 1 follows the surface shape of the object to be polished. Shape, the contact area between the polishing surface and the object to be polished increases, so the polishing rate is further improved. Examples of the material of such a flexible substrate 10 include PET or PI. In addition, examples of the material of the ductile substrate 10 include aluminum or copper.

In addition, the size of the substrate 10 is not particularly limited. For example, the outer diameter can be 200 mm or more and 2022 mm or less, and the inner diameter can be 100 mm or more and 658 mm or less.

The average thickness of the substrate 10 is not particularly limited, and may be, for example, 75 μm or more and 1 mm or less. When the average thickness of the substrate 10 is less than the lower limit, the strength or flatness of the abrasive 1 may be insufficient. On the other hand, when the average thickness of the substrate 10 exceeds the upper limit, the polishing material 1 may become thicker unnecessarily and handling may become difficult.

(Grinding layer)

The polishing layer 20 contains abrasive grains 21 and a binder 22 thereof. In addition, the polishing layer 20 includes a plurality of polishing portions 24 divided by grooves 23 on its surface.

In addition, the polishing layer 20 successively has four regions of a first region X1, a second region X2, a third region X3, and a fourth region X4 along the polishing direction thereof, that is, the circumferential direction of the base 10.

The average thickness of the polishing layer 20 (the average thickness of the polishing portion 24) is not particularly limited, and is preferably 25 μm, more preferably 30 μm, and even more preferably 200 μm. On the other hand, the upper limit of the average thickness of the polishing layer 20 is preferably 4000 μm, more preferably 3000 μm, and still more preferably 2500 μm. When the average thickness of the polishing layer 20 is less than the lower limit, the abrasion of the polishing layer 20 becomes faster, so the polishing material 1 The durability of the product may be insufficient. On the other hand, when the average thickness of the polishing layer 20 exceeds the upper limit, the polishing material 1 may become thicker unnecessarily and handling may become difficult.

(Abrasive grain)

Examples of the abrasive particles 21 include particles of diamond, alumina, silicon dioxide, and the like. Among them, diamond abrasive grains that can obtain high abrasive power are preferred. By making the abrasive grains 21 into diamond abrasive grains in this way, the abrasive force can be increased, so the surface pressure during polishing can be applied more effectively, and the gripping force increase effect due to the span resistance can be obtained more reliably.

The lower limit of the average particle diameter of the abrasive grains 21 is preferably 2 μm, more preferably 10 μm. In addition, the upper limit of the average particle diameter of the abrasive grains 21 is preferably 50 μm, more preferably 45 μm. In the case where the average particle diameter of the abrasive grains 21 is smaller than the lower limit, the polishing rate may become insufficient. On the other hand, when the average particle size of the abrasive grains 21 exceeds the upper limit, the object to be polished may be damaged. The "average particle size" here refers to the 50% value (50% particle size, D50) of the volume-based cumulative particle size distribution curve measured by a laser diffraction method or the like.

The lower limit of the content of the abrasive particles 21 relative to the abrasive layer 20 is preferably 3 vol% (vol%), more preferably 5 vol%. In addition, the upper limit of the content of the abrasive grains 21 relative to the polishing layer 20 is preferably 55 vol%, more preferably 45 vol%, and still more preferably 35 vol%. When the content of the abrasive grains 21 with respect to the polishing layer 20 is less than the lower limit, the polishing layer 20 may have insufficient polishing power. On the other hand, when the content of the abrasive grains 21 relative to the abrasive layer 20 exceeds the upper limit, there is The holding force of the abrasive grains 21 of the polishing layer 20 may be insufficient.

(Adhesive)

The main component of the adhesive 22 may be resin or inorganic substance. Examples of the resin include acrylic resins, urethane resins, epoxy resins, cellulose resins, vinyl resins, phenoxy resins, phenol resins, polyesters, and the like. In addition, examples of the inorganic substance include silicates, phosphates, and polyvalent metal alkoxides.

The main component of the adhesive 22 is preferably an inorganic substance. By setting the main component of the binder 22 as an inorganic substance in this way, the retaining force of the abrasive grains 21 of the polishing layer 20 can be improved, and the abrasive grains 21 can be prevented from falling off. Therefore, the polishing rate is less likely to decrease. The inorganic substance is also preferably a silicate having a high retention force for the abrasive grains 21 of the polishing layer 20.

In addition, when the main component of the adhesive 22 is an inorganic substance, the adhesive 22 may contain a filler having an oxide as the main component. By making the adhesive 22 contain a filler mainly composed of oxides in this way, the coefficient of elasticity of the adhesive 22 can be increased, so that the wear of the polishing layer 20 can be easily controlled. Therefore, a moderate step difference is likely to occur between adjacent regions of the polishing material 1 during polishing, so that the effect of increasing the gripping force due to the span resistance can be obtained more reliably.

Examples of the filler include: alumina, silica, cerium oxide, magnesia, zirconia, titania and other oxides, and silica-alumina, silica-zirconia, silica-magnesia And other composite oxides. These fillers can be used alone or in combination of two or more as necessary. Among them, alumina capable of obtaining high grinding power is preferred.

The average particle size of the filler also depends on the average particle size of the abrasive 21 However, the lower limit of the average particle diameter of the filler is preferably 0.01 μm, more preferably 2 μm. On the other hand, the upper limit of the average particle diameter of the filler is preferably 20 μm, more preferably 15 μm. When the average particle diameter of the filler is smaller than the lower limit, the effect of increasing the coefficient of elasticity of the adhesive 22 obtained from the filler may be insufficient, and the control of the wear of the polishing layer 20 may become insufficient. On the other hand, when the average particle diameter of the filler exceeds the upper limit, the filler may hinder the grinding power of the abrasive grains 21.

In addition, the average particle size of the filler may be smaller than the average particle size of the abrasive grains 21. The lower limit of the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 is preferably 0.1, more preferably 0.2. On the other hand, the upper limit of the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 is preferably 0.8, and more preferably 0.6. When the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 is less than the lower limit, the polishing layer 20 may be insufficient due to the insufficient effect of increasing the coefficient of elasticity of the adhesive 22 obtained from the filler The control of wear and tear may become insufficient. Conversely, when the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 exceeds the upper limit, the filler may interfere with the abrasive power of the abrasive grains 21.

The content of the filler relative to the polishing layer 20 also depends on the content of the abrasive grains 21, but the lower limit of the content of the filler relative to the polishing layer 20 is preferably 15 vol%, more preferably 30 vol%. On the other hand, the upper limit of the content of the filler relative to the polishing layer 20 is preferably 75 vol%, more preferably 72 vol%. In the case where the content of the filler relative to the polishing layer 20 is less than the lower limit, there is a possibility that the polishing layer 20 is worn out due to the insufficient effect of increasing the coefficient of elasticity of the adhesive 22 obtained from the filler The control may become insufficient. Conversely, when the content of the filler with respect to the polishing layer 20 exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains 21.

The binder 22 may contain various auxiliary agents and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, a defoamer, and a coloring agent as appropriate according to the purpose. In addition, the resin of the adhesive 22 may be at least partially crosslinked.

(groove)

The grooves 23 are formed in a lattice shape at equal intervals on the surface side of the polishing layer 20. In addition, the bottom surface of the groove 23 is formed by the surface of the base material 10.

The width of the groove 23 in each area is approximately the same width. In other words, the plurality of polishing parts 24 have the same square shape in a plan view in one area, and are arranged at substantially equal density. Regarding the width of the groove 23, the width of the groove 23 in the first area X1 and the third area X3 described later is smaller than the second area X2 and the fourth area X4. The width of the groove 23 in the first area X1 is approximately the same as the width of the groove 23 in the third area X3, and the width of the groove 23 in the second area X2 is approximately the same as the width of the groove 23 in the fourth area X4.

In addition, grooves 23 may be arranged on the boundaries dividing adjacent regions. By arranging the groove 23 on the boundary in this way, the step difference generated between the regions due to the polishing is opposed to each other with the groove 23 interposed therebetween. Therefore, the groove 23 serves as a buffer area and can suppress the occurrence of edge chipping or cracking of the object to be polished.

The width and interval of the groove 23 are the adjacent areas (the first area X1 and the second area X2, the second area X2 and the third area X3, the third area X3 and the fourth area X4, and the fourth area X4 and the first area X4). Area X1) Occupied surface of polishing part 24 The difference in the accumulation rate is appropriately set so that it is within the predetermined range.

Specifically, the lower limit of the width of the groove 23 is preferably 0.3 mm, more preferably 0.5 mm. In addition, the upper limit of the width of the groove 23 is preferably 15 mm, more preferably 10 mm. In the case where the width of the groove 23 is smaller than the lower limit, there is a possibility that the groove 23 may be blocked by abrasive powder generated by grinding. On the other hand, when the width of the groove 23 exceeds the upper limit, the object to be polished easily falls into the groove 23, so there is a possibility that the object to be polished may be damaged during polishing.

The lower limit of the interval of the grooves 23 is preferably 2 mm, more preferably 3 mm. On the other hand, the upper limit of the interval of the grooves 23 is preferably 20 mm, more preferably 10 mm. When the interval of the grooves 23 is less than the lower limit, in order to set the occupied area ratio of the polishing portion 24 to a desired range, the area of the polishing portion 24 must be reduced, and the polishing portion 24 may peel off from the base 10. Conversely, when the interval between the grooves 23 exceeds the upper limit, in order to set the occupied area ratio of the polishing portion 24 to the required range, the width of the groove 23 must be increased, and the object to be polished may fall into the groove during polishing. In 23, the object to be polished may be damaged. The "groove interval" here refers to the grid interval, that is, the pitch of the parallel grooves constituting the vertical or horizontal grid.

The lower limit of the area of each polishing portion 24 is preferably 0.5 mm ² , and more preferably 1 mm ² . On the other hand, the upper limit of the area of the polishing portion 24 is preferably 13 mm ² , and more preferably 7 mm ² . When the area of the polishing portion 24 is smaller than the lower limit, the abrasion of the polishing layer 20 becomes faster, so the durability of the polishing material 1 may be insufficient. In addition, the polishing portion 24 may peel off from the base material 10. Conversely, when the area of the polishing portion 24 exceeds the upper limit, the polishing layer 20 may be difficult to wear and a moderate step may be difficult to generate. Therefore, during polishing, the contact area of the polishing portion 24 with the object to be polished may become too large, and the polishing rate may decrease due to frictional resistance.

(Area of polishing layer)

The polishing layer 20 has a first area X1, a second area X2, a third area X3, and a fourth area X4 divided by two orthogonal straight lines passing through the center of the surface of the substrate 10. That is, the first area X1, the second area X2, the third area X3, and the fourth area X4 are arranged at substantially equal angular intervals. In addition, since the groove is configured as described above, the occupied area ratios of the first area X1 and the third area X3 are approximately the same, and the occupied area ratios of the second area X2 and the fourth area X4 are approximately the same. In addition, the occupation area ratio of the polishing portion 24 of the first region X1 and the third region X3 is larger than the occupation area ratio of the polishing portion 24 of the second region X2 and the fourth region X4. Therefore, the polishing layer 20 alternately has two types of regions with different occupied area ratios of the polishing portion 24 at substantially equal angular intervals. In this way, the polishing layer 20 alternately has two areas with different occupation area ratios of the polishing portion 24 at approximately equal angular intervals, and the object to be polished periodically moves between the areas, thereby achieving higher flattening accuracy and suppression The effect of reducing the grinding rate.

The lower limit of the occupied area ratio of the first region X1 and the third region X3 where the occupied area ratio of the polishing portion 24 is large is preferably 9%, more preferably 11%. On the other hand, the upper limit of the occupied area ratio of the first region X1 and the third region X3 is preferably 16%, and more preferably 13%. When the occupied area ratios of the first area X1 and the third area X3 are less than the lower limit, in order to set the difference with the occupied area ratios of the second area X2 and the fourth area X4 with a small area ratio as a predetermined Within the range, the occupied area ratios of the second area X2 and the fourth area X4 must be relatively reduced. Therefore, the second area X2 and the fourth The wear of the polishing layer 20 in the area X4 becomes faster, so the durability of the polishing material 1 may be insufficient. Conversely, when the occupied area ratios of the first area X1 and the third area X3 exceed the upper limit, the first area X1 and the third area X3 are less likely to be worn during polishing, which is different from the second area X2 and the fourth area. The step difference between X4 becomes larger. As a result, the crossing resistance becomes too large, so there is a risk that the edge of the object to be polished may be chipped or broken.

The lower limit of the occupied area ratio of the second region X2 and the fourth region X4 with a small occupied area ratio of the polishing portion 24 is preferably 4.5%, more preferably 6%. On the other hand, the upper limit of the occupied area ratio of the second region X2 and the fourth region X4 is preferably 9%, and more preferably 8%. When the occupied area ratio of the second region X2 and the fourth region X4 is less than the lower limit, the abrasive layer 20 wears faster, and therefore, the durability of the abrasive material 1 may be insufficient. Conversely, when the occupied area ratios of the second area X2 and the fourth area X4 exceed the upper limit, the second area X2 and the fourth area X4 are difficult to wear during polishing, and the first area X1 and A moderate level difference may occur between the third area X3, the second area X2, and the fourth area X4. Therefore, there is a possibility that the polishing rate may decrease.

The lower limit of the difference between the occupied area ratio of the first area X1 and the third area X3 where the area ratio of the polishing portion 24 is large, and the area ratio of the second area X2 and the fourth area X4 where the area ratio of the polishing portion 24 is small It is 3%, more preferably 4%. On the other hand, the upper limit of the difference in the occupied area ratio is 21%, more preferably 12%. When the difference in the occupied area ratio is less than the lower limit, it is difficult to produce a moderate step difference between the first area X1 and the third area X3, and the second area X2 and the fourth area X4 during polishing. Yu. Therefore, there is a possibility that the polishing rate may decrease. on the contrary, When the difference in the occupied area ratio exceeds the upper limit, the step difference between the first area X1 and the third area X3 and the second area X2 and the fourth area X4 during polishing becomes large. As a result, the crossing resistance becomes too large, so there is a risk that the edge of the object to be polished may be chipped or broken.

The area of each region is determined by the number of divisions of the region and the size of the substrate 10, and the lower limit of the area of each region is preferably 2000 mm ² , and more preferably 3000 mm ² . On the other hand, the upper limit of the area of each region is preferably 20000mm ^2, more preferably 15000mm ^2. When the area of each area is less than the lower limit, when the front edge of the object to be polished moves within the area, the rear edge of the object to be polished is located in other adjacent areas, and the spanning resistance becomes insufficient, so there is gripping power The increase effect may be insufficient. Conversely, when the area of each area exceeds the upper limit, the distance from when the entire object to be polished enters into the same area until the front edge of the object to be polished moves between the areas becomes longer during polishing, and the crossover resistance The obtained gripping power increasing effect may become insufficient.

In addition, the size of each area is preferably larger than the size of the substrate as the object to be polished. Specifically, each area preferably has a size that can include a circle with a diameter of 5 cm in a plan view. When the size of each area is less than or equal to the size of the substrate as the object to be polished, when the front edge of the object to be polished moves within the area, the rear edge of the object to be polished is located in other adjacent areas, and the crossover resistance is reduced. Sufficient, so there is a risk of insufficient grip increasing effect.

(Next layer)

The subsequent layer 30 is a layer for fixing the abrasive material 1 to a support for supporting the abrasive material 1 and mounted on a polishing device.

The adhesive used in the adhesive layer 30 is not particularly limited, and examples thereof include reactive adhesives, instant adhesives, hot melt adhesives, and adhesives.

The adhesive used in the adhesive layer 30 is preferably an adhesive. By using an adhesive as the adhesive used in the adhesive layer 30, the abrasive 1 can be peeled from the support and reattached, so it is easy to reuse the abrasive 1 and the support. The adhesive is not particularly limited, and examples include acrylic adhesives, acrylic-rubber adhesives, natural rubber adhesives, synthetic rubber adhesives such as butyl rubber, silicone adhesives, and polyamines. Carbamate-based adhesives, etc.

The lower limit of the average thickness of the subsequent layer 30 is preferably 0.05 mm, more preferably 0.1 mm. In addition, the upper limit of the average thickness of the adhesive layer 30 is preferably 0.3 mm, more preferably 0.2 mm. When the average thickness of the adhesive layer 30 is less than the lower limit, the adhesive force may be insufficient and the abrasive 1 may peel off from the support. On the other hand, when the average thickness of the adhesive layer 30 exceeds the above-mentioned upper limit, there is a possibility that an obstacle or the like may be caused when the abrasive material 1 is cut into a desired shape, and the workability may be reduced.

<Grinding of flat substrates>

The polishing material 1 can be preferably used for single-sided or double-sided polishing of flat substrates represented by glass substrates.

The lower limit of the ratio of the polishing rate in the fifth polishing of the polishing material 1 to the polishing rate in the first polishing (polishing rate maintenance) is preferably 60%, more preferably 75%, and still more preferably 90%. In the case where the polishing rate maintenance ratio is less than the lower limit, the polishing efficiency may decrease due to the decrease in the polishing rate. On the other hand, the upper limit of the polishing rate maintenance ratio is not particularly limited, and the larger the better. The so-called polishing rate here refers to a sapphire substrate with a diameter of 5.08 cm, a specific gravity of 3.97, and a c-plane at a polishing pressure of 200 g/cm ² , upper platen speed -25 rpm, lower platen speed 50 rpm, and sun gear speed 8 rpm The polishing rate per one shot when the polishing is repeated for 10 minutes under the conditions. Specifically, the polishing rate can be calculated by dividing the weight change (g) of the sapphire substrate before and after polishing by the surface area (μm ² ) of the substrate, the specific gravity of the substrate (g/μm ³ ), and the polishing time (minutes).

The lower limit of the polishing rate of the first polishing of the polishing material 1 is preferably 10 μm/min, more preferably 12 μm/min, and still more preferably 15 μm/min. When the polishing rate is less than the lower limit, the polishing efficiency may decrease. On the other hand, the upper limit of the polishing rate is not particularly limited.

<Method of manufacturing abrasive materials>

The polishing material 1 can be manufactured by a step of preparing a composition for a polishing layer, a step of printing the composition for a polishing layer on the surface side of the base material 10, and a step of attaching the adhesive layer 30.

(Preparation steps of composition for polishing layer)

First, in the polishing layer composition preparation step, a polishing layer composition containing a forming material of a binder 22 mainly composed of an inorganic substance, a filler, and abrasive grains 21 is prepared as a coating liquid. In addition, in order to control the viscosity or fluidity of the coating liquid, diluents such as water and alcohol are added.

Then, in the polishing layer forming step, the coating liquid prepared in the polishing layer composition preparation step is used to form a plurality of polishing portions divided by grooves 23 on the surface of the substrate 10 by printing. 24 constituted by the polishing layer 20. The abrasive layer 20 has two types of regions with different occupied area ratios of two polishing portions 24 each. Specifically, for four regions divided by two orthogonal straight lines passing through the center of the surface of the base 10, the two regions are alternately arranged along the polishing direction. In addition, the formation of the polishing layer 20 is performed by preparing a mask corresponding to the two types of regions, and printing the polishing layer composition through the mask. In order to form the groove 23, the mask has a shape corresponding to the shape of the groove 23 in each region. As the printing method, for example, screen printing, metal mask printing, or the like can be used.

After printing, the coating liquid is heated to dehydrate and heat to harden, thereby forming the polishing layer 20. Specifically, for example, the coating solution is dried at room temperature (25°C), heated and dehydrated at a temperature of 70°C or higher and 90°C or lower, and heated at 140°C or higher and 310°C or lower for 2 hours or longer. The adhesive 22 is formed by curing within 4 hours or less.

(Next layer attaching step)

Finally, in the step of attaching the adhesive layer, the adhesive layer 30 can be attached to the back of the substrate 10 to obtain the abrasive material 1.

<Advantages>

In this polishing material 1, the difference in the occupied area ratio of the plurality of polishing portions 24 of a pair of the regions adjacent to the polishing direction is within the above range. Therefore, in the polishing material 1, the region with a small occupied area is subjected to a moderately large polishing pressure during polishing. Due to the difference in polishing pressure, the area with a small occupied area is worn first, so that the polishing material 1 has a moderate step difference between adjacent areas. Therefore, during polishing, while moving the object to be polished from a small height area to a large height area or in the opposite direction, Perform grinding. The gripping force of the polishing material 1 increases due to the spanning resistance when moving between the regions, and the surface pressure is further increased in the regions where the height is large, that is, the occupied area ratio is large. Thereby, the polishing material 1 can more effectively apply the surface pressure during polishing, so it has a high polishing rate and flattening accuracy, and the polishing rate is not easy to decrease in a relatively long period of time due to the gripping force. Therefore, the polishing material 1 does not require frequent dressing, so it can reduce the running cost or simplify the step management, and has excellent polishing accuracy and polishing efficiency. Furthermore, there is no need to newly supply abrasive grains at the time of polishing, so the polishing using this abrasive 1 has a lower polishing cost than the polishing using free abrasive grains.

[Second Embodiment]

Hereinafter, the second embodiment of the present invention will be described in detail while appropriately referring to the drawings.

The polishing material 2 shown in FIG. 2 has a disc shape and mainly includes a base material 11 and a polishing layer 20 laminated on the surface side of the base material 11. In addition, the polishing material 2 includes an adhesive layer 30 laminated on the back side of the base material 11. Furthermore, the polishing material 2 includes a support 40 laminated via the adhesive layer 30 and a support adhesive layer 41 laminated on the back side of the support 40. In addition, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

(Substrate)

The substrate 11 is a plate-shaped member for supporting the polishing layer 20. The base material 11 is divided into a first area X1, a second area X2, a third area X3, and a fourth area X4 along the polishing direction. That is, the bottom surface of the groove located at the boundary of the adjacent region is constituted by the surface of the support 40. By dividing the substrate 11 into various regions, A plurality of substrates 11 on which polishing layers 20 with different occupied area ratios of the polishing portions 24 are formed are laminated to form the polishing material 2. Therefore, it is different from the case where a region having a different occupied area ratio of the polishing portions 24 is formed on one substrate In comparison, the abrasive 2 is easy to manufacture.

The material, size, and average thickness of the base material 11 may be the same as those of the base material 10 of the first embodiment.

(Support)

The support 40 is a plate-shaped member for supporting the base material 11 and fixing the polishing material 2 to a polishing device.

The material of the support 40 may include: polypropylene, polyethylene, polytetrafluoroethylene, polyvinyl chloride and other thermoplastic resins or polycarbonate, polyamide, polyethylene terephthalate and other engineering plastics. . By using such a material in the support 40, the support 40 has flexibility. The abrasive 2 follows the surface shape of the object to be polished, and the polishing surface and the object to be polished are easily in contact with each other, thereby improving polishing efficiency .

The average thickness of the support 40 can be set to 0.5 mm or more and 3 mm or less, for example. When the average thickness of the support 40 is less than the lower limit, the strength of the support 40 may be insufficient. On the other hand, when the average thickness of the support 40 exceeds the upper limit, it may be difficult to mount the support 40 in a polishing device or the support 40 may not have sufficient flexibility.

(Support Adhesion Layer)

The support adhesive layer 41 is a layer for mounting the support 40 to the polishing device.

The type and average thickness of the adhesive of the support adhesive layer 41 may be the same as the adhesive layer 30.

<Method of manufacturing abrasive materials>

The polishing material 2 can be supported by the step of preparing the polishing layer composition, the step of printing the polishing layer composition on the surface side of the substrate 11, the step of fixing the substrate 11 to the support 40, and the attachment support. The step of bulk bonding layer 41 is manufactured.

(Preparation steps of composition for polishing layer)

The preparation step of the polishing layer composition is the same as the preparation step of the polishing layer composition in the first embodiment, so the description is omitted.

(Printing steps)

Then, in the printing step, the coating liquid prepared in the polishing layer composition preparation step is used to print the polishing layer composition on the substrate 11.

Specifically, two substrates 11 are prepared separately for use in two types of regions with different occupation area ratios of the polishing portion 24 of the polishing material 2. A mask corresponding to the base material 11 is prepared, and the polishing layer composition is printed via the mask. Furthermore, in order to form the groove 23, the mask has a shape corresponding to the shape of the groove 23 in each region. The printing method may be the same as in the first embodiment.

(Substrate attachment step)

Then, in the substrate attaching step, the substrate 11 on which the polishing layer 20 is formed is cut so as to conform to the shape of each region of the polishing material 2, and is respectively attached to the support 40 via the adhesive layer 30 .

(Steps to attach the support to the layer)

Finally, in the support adhesive layer attaching step, the support adhesive layer 41 can be attached to the back of the support 40 to obtain the abrasive material 2.

<Advantages>

The polishing material 2 is provided with the support 40, so that the handling of the polishing material 2 becomes easy.

[Other embodiments]

The present invention is not limited to the above-mentioned embodiment, and can be implemented with various changes and improvements other than the above-mentioned aspects.

In the above-mentioned embodiment, the case where the abrasive material is a disc shape has been described, but the shape of the abrasive material is not limited to the disc shape. For example, the abrasive may be square. The size of the case where the abrasive is a square shape is not particularly limited, and for example, it can be a square shape with a side of 140 mm or more and 160 mm or less.

In the above-mentioned embodiment, the grooves are grid-shaped, that is, the planar shape of the polishing portion is square, but the planar shape of the polishing portion may not be square, for example, a shape that overlaps polygons other than quadrilateral , Round shape, etc.

In addition, in the above-described embodiment, the bottom surface of the plurality of grooves is the surface of the substrate, but the depth of the grooves may be smaller than the average thickness of the polishing layer, and the grooves may not reach the surface of the substrate. In this case, the depth of the groove can be set to 50% or more of the average thickness of the polishing layer. When the depth of the groove is smaller than the lower limit, the groove may disappear due to wear, and the durability of the abrasive may be poor.

In the above-mentioned embodiment, the case where the occupied area ratio of the two regions differs depending on the width of the groove has been described, but other parameters, such as the shape of the groove (the shape of the polishing portion) or the interval or the number of grooves may also be used. The occupied area ratio is changed according to the number.

In the above embodiment, the polishing material including two types of regions with different occupied area ratios has been described, but the number of regions with different occupied area ratios is not limited to two types. The number of regions with different occupied area ratios may be three or more.

In addition, in the above-mentioned embodiment, the case where multiple types of areas are alternately arranged along the polishing direction has been described, but the multiple types of areas may not be alternately arranged.

In the above-mentioned embodiment, the case where the base material is divided into four is shown as each area, but the number of divisions is not limited to four, and it may be divided into two, three, or five or more. Furthermore, the lower limit of the number of divisions is preferably 4. When the number of divisions is less than the lower limit, the number of times per unit time that the object to be polished spans between regions with different occupied area ratios during polishing decreases, so the gripping force increase effect due to span resistance becomes Insufficiency.

In the first embodiment described above, the case where the abrasive has an adhesive layer has been described, but the adhesive layer is not an essential constituent element and may be omitted. For example, the adhesive layer may be located on the side of the support, and other fixing methods such as screw fixing may also be used to fix it to the support.

In the above-mentioned embodiment, the case where the groove is a space has been described, but the abrasive material may be provided with a filling portion filled in the groove. The filling part preferably contains resin or an inorganic substance as a main component, and does not substantially contain abrasive grains. In addition, the term "filled portion substantially free of abrasive grains" means that the content of abrasive grains is less than 0.001 vol%, preferably less than 0.0001 vol%.

When the polishing material has a filled portion, the lower limit of the ratio of the average thickness of the filled portion to the average thickness of the polishing layer is preferably 0.1, more preferably 0.5, still more preferably 0.8, and particularly preferably 0.95. On the other hand, the upper limit of the ratio of the average thickness of the filled portion to the average thickness of the polishing layer is preferably 1, and more preferably 0.98. Fill in When the ratio of the average thickness of the filling portion to the average thickness of the polishing layer is less than the lower limit, the effect of preventing the object to be polished from falling into the groove during polishing may become insufficient. Conversely, when the ratio of the average thickness of the filling portion to the average thickness of the polishing layer exceeds the upper limit, the polishing layer may not sufficiently contact the object to be polished at the start of polishing, or the polishing pressure may be dispersed to The polishing pressure applied to the polishing layer by filling the layer may become insufficient. The "average thickness of the filled portion" herein refers to the average value of the distance between the surface of the base material and the surface of the filled portion.

[Example]

Hereinafter, the present invention will be described in more detail with examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]

Prepare diamond abrasive grains, and measure the average particle size using Nikkiso Co., Ltd. "Microtrac MT3300EXII". The average particle diameter of the diamond abrasive grains was 44 μm. In addition, the type of diamond of the abrasive grains was treated diamond coated with 55% by mass nickel.

Sodium silicate (No. 3 sodium silicate) as a binder, the diamond abrasive grains, and alumina (Al ₂ O ₃ , average particle size 12 μm) as a filler are mixed, and the diamond abrasive grains are opposed to the polishing layer It was prepared so that the content of the powder became 5 vol% and the content of the filler relative to the polishing layer became 71 vol% to obtain a coating liquid.

A disc-shaped aluminum plate with an average thickness of 300 μm, an outer diameter of 386 mm, and an inner diameter of 148 mm was prepared as a base material. The 4 straight lines passing through the center of the substrate surface and forming an angle of 45 degrees with the adjacent straight line are divided into 8 areas, so as to extend along the circumference The polishing layer is formed by alternately arranging two types of regions with different occupied area ratios. Specifically, a polishing layer with a square shape of 1.5 mm on one side and a groove width of 3.5 mm is formed in a region where the occupied area ratio is small, and a top view of the polishing region is formed in a region where the occupied area ratio is large. The shape is a circular shape with a diameter of 1.2 mm, and a polishing layer with a groove width of 3.8 mm. Furthermore, a mask corresponding to the groove is used as a printed pattern, thereby forming a groove in the polishing layer. In addition, the polishing portion has a square pattern that is arranged regularly. The occupied area ratios of the two types of areas and their differences are shown in Table 1. Furthermore, the area has a size that can include a circle with a diameter of 8.5 cm in a plan view.

The coating liquid is dried at room temperature (25°C), heated and dehydrated at a temperature of 60°C or more and 100°C or less, and then cured at 300°C for 2 hours or more and 4 hours or less.

In addition, a rigid vinyl chloride resin plate with an average thickness of 1 mm was used as a support substrate and fixed to a support of the polishing apparatus, and the back surface of the substrate was bonded to the surface of the support with an adhesive with an average thickness of 130 μm. Use double-sided tape as the adhesive. In this way, the abrasive material of Example 1 was obtained.

[Example 2]

A polishing layer with a square shape of 1.5 mm on one side and a groove width of 3.5 mm is formed in a region with a small occupied area, and a polishing layer with a diameter of 1.5 in a plan view of a large occupied area. A polishing layer with a square shape of mm and a groove width of 2.346 mm. Except for the above, the polishing material of Example 2 was obtained in the same manner as in Example 1.

[Example 3]

The area is a square shape with a side of 5mm, and the polishing layer is formed in the area with a small area ratio. The planar shape of the polishing part is a square shape with a diameter of 1.69mm and the groove width is 3.31mm. The planar shape of the polishing portion formed therein is a polishing layer having a square shape with a diameter of 1.2 mm and a groove width of 3.8 mm. Except for the above, the abrasive material of Example 3 was obtained in the same manner as in Example 1.

[Example 4]

The polishing material of Example 4 was obtained in the same manner as Example 3 except that the area was a square shape of 25 mm on one side.

[Comparative Example 1]

The polishing layer does not have regions with different occupied area ratios, and the polishing layer is formed on the entire surface of the aluminum plate as the substrate. The polishing part has a square shape with a diameter of 1.5 mm in plan view and a groove width of 3.5 mm. , The polishing material of Comparative Example 1 was obtained in the same manner as in Example 1.

[Comparative Example 2]

Except that the planar shape of the polishing portion was a square shape with a diameter of 1.5 mm, and the width of the groove was a polishing layer of 3.8 mm, a polishing material of Comparative Example 2 was obtained in the same manner as in Comparative Example 1.

[Comparative Example 3]

It was obtained in the same manner as in Comparative Example 1, except that the polishing portion was formed in a square shape with a diameter of 1.5 mm in plan view and a groove width of 2.346 mm. The abrasive of Comparative Example 3.

[Grinding conditions]

The polishing materials obtained in the aforementioned Examples 1 to 4 and Comparative Examples 1 to 3 were used to polish the sapphire substrate. For the sapphire substrate, a sapphire substrate with a diameter of 5.08 cm, a specific gravity of 3.97, and a c-plane (only as-lap processing) was used. In the polishing, a commercially available double-sided polishing machine was used. The carrier of the double-sided grinder is epoxy glass with a thickness of 0.4 mm. Regarding the grinding, the grinding pressure was set to 200 g/cm ² , and the upper platen rotation speed was -25 rpm, the lower platen rotation speed was 50 rpm, and the sun gear rotation speed was 8 rpm, and the grinding was performed 5 times in units of 10 minutes. At this time, as a coolant, 30 cc of Idemitsu Kosan Co., Ltd. "Daphne Cut GS50K" is supplied every minute.

<grinding rate>

When calculating the polishing rate, a sapphire substrate subjected to the first polishing for 10 minutes was used. The polishing rate is calculated by dividing the weight change (g) of the substrate before and after polishing by the surface area (cm ² ) of the substrate, the specific gravity of the substrate (g/cm ³ ), and the polishing time (minutes). The results are shown in Table 2.

<Maintenance rate>

The maintenance rate of the polishing rate is calculated by dividing the polishing rate in the fifth polishing by the polishing rate in the first polishing. The results are shown in Table 2.

According to Table 2, the polishing materials of Examples 1 to 4 have the same polishing rate as the polishing materials of Comparative Examples 1 to 3, and the polishing rate is less likely to decrease. In contrast, since the polishing materials of Comparative Examples 1 to 3 do not have regions with different occupied area ratios, it is considered that the gripping force increase effect due to the span resistance cannot be obtained, and the maintenance rate of the polishing rate decreases. From this, it can be seen that the polishing materials of Examples 1 to 4 have two types of regions with different occupied area ratios of the polishing portions, and therefore have excellent polishing rate and polishing rate maintenance.

In addition, if Examples 1 to 2 are compared with Examples 3 to 4, the polishing rate in Examples 1 to 2 is not easily reduced. From this, it can be seen that since the area has a size that can include a circle with a diameter of 5 cm in a plan view, the polishing rate maintenance is more excellent.

[Industrial availability]

The polishing material of the present invention has excellent polishing accuracy, low polishing efficiency and low polishing cost. Therefore, the abrasive can be preferably used for the polishing of glass substrates used in electronic devices, or difficult-to-process substrates such as sapphire or silicon carbide.

1‧‧‧Grinding material

10‧‧‧Substrate

20‧‧‧Grinding layer

21‧‧‧Grit

22‧‧‧Binder

23‧‧‧Slot

24‧‧‧Grinding Department

X1‧‧‧Region 1

X2‧‧‧Section 2

X3‧‧‧Region 3

X4‧‧‧Region 4

Claims (7)

An abrasive material comprising a substrate and an abrasive layer laminated on the surface side of the substrate and containing abrasive grains and a binder, and the abrasive material is characterized in that the abrasive layer is provided with grooves on its surface A plurality of divided polishing parts, and a plurality of regions having different occupation area ratios of the plurality of polishing parts along the polishing direction, and the occupation area ratio of the plurality of polishing parts of a pair of the regions adjacent to the polishing direction The difference is 3% or more and 21% or less, and the plurality of polishing parts have the same shape in a plan view in one of the regions. The abrasive material described in the first item of the scope of the patent application, wherein each of the regions has a size that can include a circle with a diameter of 5 cm in a plan view. The polishing material described in the first item of the scope of patent application, wherein in a pair of regions adjacent to each other along the polishing direction, the occupied area ratio of the plurality of polishing portions in one region is 4.5% or more and 9% or less, and the other The occupied area ratio of the plurality of polishing parts in the region is 9% or more and 16% or less. The abrasive material according to the first item of the scope of patent application, wherein the abrasive grains are diamond abrasive grains. The abrasive material described in item 1 of the scope of patent application, wherein the main component of the adhesive is an inorganic substance. The abrasive material described in item 5 of the scope of the patent application, wherein the adhesive contains a filler mainly composed of oxides. The polishing material described in the first item of the scope of patent application is used for flat polishing of substrates.

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