JP6046865B1 - Polishing pad and polishing pad manufacturing method - Google Patents

Abstract

An object of the present invention is to provide a polishing pad that has a high leveling accuracy and is less likely to decrease the polishing rate over a relatively long period of time. The polishing pad of the present invention is a polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof, wherein the polishing layer is in the polishing direction. The average value of the maximum height of the polishing layer in the plurality of divided portions according to the distance from the center of gravity of the entire polishing layer for each of the above regions is divided. The reference height difference between a pair of adjacent regions is 5 μm or more and less than 100 μm. The plurality of types of regions are preferably composed of a reference region and a low height region in which the average height of the polishing layer is smaller than the reference region, and are arranged alternately along the polishing direction. It is preferable that the polishing layer has a plurality of polishing portions that are arranged at substantially equal density and have a fixed shape in plan view.

Description

  The present invention relates to a polishing pad and a method for manufacturing the polishing pad.

  In recent years, electronic devices such as hard disks have been refined. As a substrate material for such an electronic device, glass is often used in consideration of rigidity, impact resistance, and heat resistance that can be reduced in size and thickness. This glass substrate is a brittle material, and mechanical strength is remarkably impaired by scratches on the surface. For this reason, polishing of such a substrate (workpiece) requires a flattening accuracy with few scratches as well as processing efficiency.

  In general, when trying to improve the flattening accuracy of the finish, the processing time tends to be long, and the processing efficiency and the flattening accuracy are in a trade-off relationship. For this reason, it is difficult to achieve both processing efficiency and flattening accuracy. On the other hand, in order to achieve both processing efficiency and flattening accuracy, a polishing pad having a polishing layer containing a binder and abrasive grains, and the polishing layer having a polishing portion has been proposed (Japanese Translation of International Patent Publication No. 2002-542057). No. publication).

  However, when such a conventional polishing pad is polished for a certain period of time, the polishing rate decreases due to crushing of abrasive grains or clogging of the polishing layer surface. In order to regenerate the lowered polishing rate, it is necessary to perform so-called dressing, in which the surface of the polishing pad is scraped off and a new surface is exposed on the surface. It is necessary to clean the polishing pad before and after this dress, and this dress is a time-consuming operation. Since the polishing of the glass substrate is interrupted during the dressing, the polishing efficiency of the conventional polishing pad is greatly reduced by the dressing.

Japanese translation of PCT publication No. 2002-542057

  The present invention has been made in view of such inconveniences, and an object of the present invention is to provide a polishing pad having high planarization accuracy and in which the polishing rate is hardly lowered for a relatively long period of time.

  The invention made to solve the above problems is a polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof, wherein the polishing layer is The maximum height of the polishing layer in the plurality of divided portions according to the distance from the center of gravity of the entire polishing layer in each of the regions, which are divided along the polishing direction and have different average heights. When the average value is used as the reference height of the region, the difference in reference height between the pair of adjacent regions is 5 μm or more and less than 100 μm.

  In the polishing pad, since the polishing layer is divided along the polishing direction and has a plurality of types of regions having different average heights, the workpiece is changed from a region having a small height to a region having a high height or vice versa at the time of polishing. Polished while moving. By making this height difference within the above range, the gripping force of the polishing pad is improved by the resistance to overcoming, and the surface pressure is increased in a region where the height is large. As a result, the polishing pad can more effectively utilize the surface pressure during polishing, so that it has a high leveling accuracy and the polishing rate is unlikely to decrease over a relatively long period of time. Therefore, since the polishing pad does not need to be dressed frequently, running cost can be reduced and process management can be simplified.

  The said polishing pad is a disk-shaped thing, It is good for the said several types of area | region to be arrange | positioned at substantially equal angular intervals. In general, polishing of a glass substrate or the like is performed by contacting a workpiece while rotating a polishing pad. Therefore, by using a disk-shaped object and arranging a plurality of types of regions at substantially equal angular intervals, the workpiece is periodically moved between the regions, so that even higher planarization accuracy and lower polishing rate can be achieved. A deterrent effect is obtained.

  The plurality of types of regions are preferably composed of a reference region and a low height region in which the average height of the polishing layer of the polishing layer is smaller than the reference region, and are arranged alternately along the polishing direction. Thus, by alternately arranging the two types of regions having different average heights, it is possible to suppress an increase in the manufacturing cost of the polishing pad while maintaining a high leveling accuracy and an effect of suppressing a decrease in the polishing rate.

  It is preferable that the polishing layer has a plurality of polishing portions that are arranged at substantially equal density and have a fixed shape in plan view. In this way, by arranging constant-shaped polishing parts at approximately equal density and arranging the polishing parts regularly, the surface pressure and the number of polishing action points on the workpiece to be polished can be easily controlled, so that the flatness is flat. The accuracy is further increased.

  Therefore, the polishing pad is suitably used for polishing flat substrates such as glass substrates.

  Another invention made to solve the above problems is a method for producing a polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof. And a step of printing a composition for a polishing layer containing abrasive grains and a binder material for each of a plurality of regions divided on the surface side of the substrate film along the polishing direction, and the entire polishing layer for each region When the average value of the maximum heights of the polishing layers in a plurality of divided portions according to the distance from the center of gravity is used as the reference height of the region, the number of printings in the printing step or the composition of the polishing layer composition is varied. Thus, the difference in reference height between a pair of adjacent regions is adjusted to 5 μm or more and less than 100 μm.

  The manufacturing method of the polishing pad has a plurality of types of regions having different average heights by changing the number of times of printing corresponding to each region or the composition of the polishing layer composition in the printing step, and a pair of adjacent above-mentioned A polishing pad in which the difference in the reference height of the regions is within the above range can be manufactured easily and reliably.

  Here, the “average height of the polishing layer” means the average height of the polishing layer from the base film average interface measured using, for example, a laser displacement meter (“LJV7020” manufactured by Keyence Corporation). . The “plurality of regions having different average heights” means a plurality of regions having different average heights, with a region having a deviation of 3% or less from the average height as one region. Further, “a plurality of divided portions corresponding to the distance from the center of gravity of the entire polishing layer” means that the shortest distance from the center of gravity of the entire polishing layer to the region is X [mm] and the longest distance is Y [mm]. The distance from the center of gravity of the entire polishing layer is not less than X [mm] (X + 1 / n (Y−X)) [mm], (X + 1 / n (Y−X)) [mm] or more (X + 2 / n (Y −X)) Less than [mm], (X + (n−1) / n (Y−X)) means n parts divided into [mm] or more and Y [mm] or less. Here, n is an integer greater than or equal to 2, for example, n = 3.

  “Area is substantially equiangular” means that the difference between the minimum value and the maximum value of the angle formed by the radiation connecting the center of the disk and the center of each area is 10 ° or less. “Equal density” means that the deviation in the interval and the deviation in the area of the polishing parts are within 10% of the average value. The “polishing direction” is a direction in which the polishing pad moves during polishing. For example, in the case of a disc-shaped polishing pad, it indicates the circumferential direction.

  As described above, the polishing pad of the present invention has high planarization accuracy, and the polishing rate is difficult to decrease over a relatively long period of time. Therefore, since the polishing pad does not need to be dressed frequently, running cost can be reduced and process management can be simplified.

1 is a schematic plan view showing a polishing pad according to an embodiment of the present invention. It is typical sectional drawing in the AA of FIG. 1A. It is typical sectional drawing which shows the polishing pad of embodiment different from FIG. 1B.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

<Polishing pad>
The polishing pad 1 shown in FIGS. 1A and 1B has a disk shape, and mainly includes a base film 10 and a polishing layer 20 laminated on the surface side. In addition, the polishing pad 1 includes an adhesive layer 30 that is laminated on the back surface side of the base film 10.

(Base film)
The base film 10 is a plate-like member for supporting the polishing layer 20.

  The material of the base film 10 is not particularly limited, but polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyimide (PI), polyethylene naphthalate (PEN), aramid, aluminum, copper, etc. Can be mentioned. Among these, PET and PI that have good adhesion to the polishing layer 20 are preferable. Moreover, the process which improves adhesiveness, such as a chemical process, a corona process, and a primer process, may be performed on the surface of the base film 10.

  Although it does not restrict | limit especially as a magnitude | size of the said base film 10, For example, it can be set as the annular | circular shape with an outer diameter of 270 mm or more and 320 mm or less, and an internal diameter of 80 mm or more and 130 mm or less.

  Although it does not restrict | limit especially as average thickness of the said base film 10, For example, it can be 75 micrometers or more and 1 mm or less. When the average thickness of the base film 10 is less than the lower limit, the strength and flatness of the polishing pad 1 may be insufficient. On the other hand, when the average thickness of the base film 10 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and may be difficult to handle.

(Polishing layer)
The polishing layer 20 includes abrasive grains 21 and a binder 22 thereof. The polishing layer 20 is divided into a plurality of regions X1, X2, X3, and X4 along the polishing direction, and has two types of regions X1 and X3, and regions X2 and X4 having different average heights. The polishing layer 20 has a plurality of grooves 23 on the surface.

  The average thickness of the polishing layer 20 (the average thickness excluding the grooves 23) is not particularly limited, but the lower limit of the average thickness of the polishing layer 20 is preferably 25 μm, and more preferably 30 μm. The upper limit of the average thickness of the polishing layer 20 is preferably 1000 μm, and more preferably 800 μm. When the average thickness of the polishing layer 20 is less than the lower limit, the durability of the polishing layer 20 may be insufficient. On the other hand, when the average thickness of the polishing layer 20 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and may be difficult to handle.

(Abrasive grains)
Examples of the abrasive 21 include particles such as diamond, alumina, and silica. Among these, diamond abrasive grains that can provide high polishing efficiency are preferable.

  The lower limit of the average particle size of the abrasive grains 21 is preferably 3 μm and more preferably 10 μm. Moreover, as an upper limit of the average particle diameter of the said abrasive grain 21, 15 micrometers is preferable and 14 micrometers is more preferable. When the average particle size of the abrasive grains 21 is less than the lower limit, the polishing rate may be insufficient. On the other hand, when the average particle diameter of the abrasive grains 21 exceeds the upper limit, the workpiece may be damaged.

  As a minimum of content with respect to the polishing layer 20 of the said abrasive grain 21, 35 volume% is preferable and 40 volume% is more preferable. Moreover, as an upper limit of content with respect to the polishing layer 20 of the said abrasive grain 21, 70 volume% is preferable and 65 volume% is more preferable. When the content of the abrasive grains 21 with respect to the polishing layer 20 is less than the lower limit, the polishing power of the polishing layer 20 may be insufficient. On the other hand, when the content of the abrasive grains 21 with respect to the polishing layer 20 exceeds the upper limit, the workpiece may be damaged.

(binder)
Although it does not specifically limit as a composition which comprises the said binder 22, The thing which has a thermosetting resin as a main component is good. Examples of the thermosetting resin include polyurethane, polyphenol, epoxy, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacryl, acrylic ester, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polyamide. Among these, thermosetting epoxy is preferable. The thermosetting epoxy can easily ensure good dispersibility of the abrasive grains 21 and good adhesion to the base film 10 when constituting the binder 22. Here, the “main component” means a component having the highest content, for example, a component having a content of 50% by mass or more.

  An inorganic substance may be used as the main component of the binder 22. Examples of such inorganic substances include silicates, phosphates, and polyvalent metal alkoxides. Among them, a silicate having a high abrasive particle holding power of the polishing layer 20 is preferable.

  The binder 22 may appropriately contain various auxiliaries and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a colorant depending on the purpose. The resin of the binder 22 may be at least partially crosslinked.

(groove)
The polishing layer 20 has a plurality of polishing portions 24 whose surfaces are divided by grooves 23. The bottom surface of the groove 23 that divides the polishing portion 24 is constituted by the surface of the base film 10. Further, the grooves 23 are arranged in a lattice pattern at equal intervals on the surfaces of the region X1, the region X2, the region X3, and the region X4 of the polishing layer 20. That is, the polishing unit 24 has a constant shape in plan view and is arranged with substantially equal density. By arranging the constant-shaped polishing portions 24 at substantially equal density in this way, the surface pressure and the number of polishing action points on the workpiece to be polished can be easily controlled, and the planarization accuracy is further increased.

  The lower limit of the average width of the groove 23 is preferably 0.3 mm, and more preferably 0.5 mm. Further, the upper limit of the average width of the groove 23 is preferably 10 mm, and more preferably 8 mm. When the average width of the groove 23 is less than the lower limit, the polishing powder generated by polishing may be clogged in the groove 23. On the other hand, when the average width of the groove 23 exceeds the above upper limit, there is a possibility that the workpiece is damaged during polishing.

As a minimum of each average area of the above-mentioned polish part 24, 1 mm ² is preferred and 2 mm ² is more preferred. Moreover, as an upper limit of the average area of the said grinding | polishing part 24, 150 mm < ² > is preferable and 130 mm < ² > is more preferable. When the average area of the polishing unit 24 is less than the lower limit, the polishing unit 24 may be peeled off from the base film 10. On the other hand, when the average area of the polishing part 24 exceeds the upper limit, the contact area of the polishing layer 20 to the work body during polishing is increased, and the polishing efficiency may be reduced.

  The lower limit of the area occupation ratio of the plurality of polishing portions 24 with respect to the entire polishing layer 20 is preferably 20% and more preferably 30%. Moreover, as an upper limit of the area occupation rate with respect to the said whole polishing layer 20 of the said some grinding | polishing part 24, 60% is preferable and 55% is more preferable. When the area occupancy ratio of the plurality of polishing portions 24 with respect to the entire polishing layer 20 is less than the lower limit, the surface pressure to the workpiece to be polished and the number of polishing action points are insufficiently controlled, so that sufficient planarization is achieved. The accuracy may not be obtained. On the other hand, when the area occupancy ratio of the plurality of polishing portions 24 with respect to the entire polishing layer 20 exceeds the upper limit, the frictional resistance during polishing of the polishing layer 20 becomes high, and the workpiece may be damaged. The “area of the entire polishing layer” is a concept including the area of the groove when the polishing layer has a groove.

(Abrasive layer area)
The two types of region X1, region X3, region X2, and region X4 are a reference region X1 and region X3, and a low height region X2 and region X4 in which the average height of the polishing layer 20 is smaller than the reference region X1 and region X3. And arranged alternately along the polishing direction. Each region is divided by two straight lines that pass through the center of the ring of the polishing layer 20 and are orthogonal to each other. That is, the region X1, the region X2, the region X3, and the region X4 are disposed at substantially equal angular intervals. By disposing the two types of regions at substantially equal angular intervals in this manner, the workpiece is periodically moved between the regions, so that a further higher leveling accuracy and an effect of suppressing a reduction in the polishing rate can be obtained. .

  In addition, one of the grooves 23 may be disposed so as to coincide with a boundary dividing the region. By aligning one of the grooves 23 with the boundary, the step between the regions faces each other with the groove 23 interposed therebetween, so that the groove 23 serves as a buffer area to prevent the chipping or cracking of the work piece. it can.

  The lower limit of the difference in reference height between adjacent areas (for example, the difference in reference height between X1 and X2) is 5 μm, more preferably 20 μm, and even more preferably 40 μm. On the other hand, the difference in the reference height of the region is less than 100 μm, more preferably less than 90 μm, and still more preferably less than 80 μm. When the difference in the reference height of the region is less than the lower limit, the resistance to climbing is reduced, so that the effect of improving the grip force by the resistance to climbing may be insufficient. On the contrary, when the difference in the reference height of the region is equal to or more than the upper limit, the overcoming resistance is too large, and there is a possibility that the chipping or cracking of the workpiece is generated.

(Adhesive layer)
The adhesive layer 30 is a layer that supports the polishing pad 1 and fixes the polishing pad 1 to a support for mounting on the polishing apparatus.

  Although it does not specifically limit as an adhesive agent used for this contact bonding layer 30, For example, a reactive adhesive, an instantaneous adhesive agent, a hot melt adhesive agent, an adhesive agent etc. are mentioned.

  As the adhesive used for the adhesive layer 30, a pressure-sensitive adhesive is preferable. By using a pressure-sensitive adhesive as the adhesive used for the adhesive layer 30, the polishing pad 1 and the support can be easily reused because the polishing pad 1 can be peeled off from the support and replaced. Such an adhesive is not particularly limited. For example, an acrylic adhesive, an acrylic-rubber adhesive, a natural rubber adhesive, a synthetic rubber adhesive such as butyl rubber, a silicone adhesive, and a polyurethane adhesive. Agents and the like.

  The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, and more preferably 0.1 mm. Moreover, as an upper limit of the average thickness of the contact bonding layer 30, 0.3 mm is preferable and 0.2 mm is more preferable. When the average thickness of the adhesive layer 30 is less than the above lower limit, the adhesive force is insufficient and the polishing pad 1 may be peeled off from the support. On the other hand, when the average thickness of the adhesive layer 30 exceeds the above upper limit, for example, due to the thickness of the adhesive layer 30, there is a risk that workability may be lowered, such as causing trouble when the polishing pad 1 is cut into a desired shape.

The lower limit of the ratio of the polishing rate at the fifth polishing to the polishing rate in the first polishing of the polishing layer 20 is preferably 90%, more preferably 95%, and even more preferably 99%. When the ratio of the polishing rates is less than the lower limit, the polishing efficiency may decrease due to the decrease in the polishing rate. Here, the polishing rate refers to a soda lime glass having a diameter of 6.25 cm and a specific gravity of 2.4 under conditions of a polishing pressure of 150 g / cm ² , an upper surface plate rotation speed of 60 rpm, a lower surface plate rotation speed of 90 rpm, and a SUN gear rotation speed of 30 rpm. It refers to the polishing rate per time when repeated for 15 minutes. Specifically, the polishing rate is obtained by dividing the weight change (g) of the glass substrate before and after polishing by the surface area of the substrate (μm ² ), the specific gravity of the substrate (g / μm ³ ), and the polishing time (minutes). It can be calculated.

<Polishing pad manufacturing method>
The said polishing pad 1 can be manufactured by the process of preparing the composition for polishing layers, the process of printing the composition for polishing layers on the surface side of the base film 10, and the process of sticking the contact bonding layer 30. The polishing pad 1 adjusts the difference between the reference heights of a pair of adjacent regions within a predetermined range by varying the number of times of printing in the printing step or the composition of the composition for the polishing layer. Hereinafter, these two methods will be described.

[Method by number of prints]
First, the manufacturing method of the said polishing pad 1 which adjusts the difference of the reference | standard height of a pair of adjacent said area | region within the predetermined range by varying the frequency | count of printing is demonstrated.

(Polishing layer composition preparation step)
First, in the polishing layer composition preparation step, a solution in which the polishing layer composition containing the abrasive grains 21 and the binder 22 thereof is dispersed in a solvent is prepared as a coating liquid. The solvent is not particularly limited as long as the material for forming the binder 22 is soluble. Specifically, methyl ethyl ketone (MEK), isophorone, terpineol, N methylpyrrolidone, cyclohexanone, propylene carbonate, or the like can be used. In order to control the viscosity and fluidity of the coating liquid, a diluent such as water, alcohol, ketone, acetate ester and aromatic compound may be added.

(Printing process)
Next, in the printing process, using the coating liquid prepared in the polishing layer composition preparation process, the surface layer of the base film 10 is divided into two regions divided along the polishing direction. Print things. Specifically, the surface of the base film 10 is divided so that two regions are alternately arranged along the polishing direction. That is, a mask corresponding to the two types of regions is prepared, and the polishing layer composition is printed through the mask. The mask has a shape corresponding to the shape of the groove 23 in order to form the groove 23.

  As this printing method, for example, screen printing, metal mask printing or the like can be used. After printing, the polishing layer 20 is formed by heat-dehydrating and heat-curing the coating liquid. Specifically, for example, the coating liquid is dried at room temperature (25 ° C.), heated and dehydrated with heat of 70 ° C. to 90 ° C., and then cured with heat of 100 ° C. to 160 ° C. to form the binder 22. To do.

  In the above printing step, printing of the polishing layer composition using a mask for printing only in the reference region and printing of the polishing layer composition using a mask for printing only in the low height region are performed separately. . At this time, the average height of the polishing layer 20 can be increased by increasing the number of times the reference region is printed. Thus, by making the number of printings different, the difference in reference height between a pair of adjacent areas is adjusted within a predetermined range.

(Adhesive layer application process)
Finally, in the adhesive layer attaching step, the adhesive layer 30 can be attached to the back surface of the base film 10 to obtain the polishing pad 1.

[Method by composition of polishing layer composition]
First, the manufacturing method of the said polishing pad 1 which adjusts the difference of the reference | standard height of a pair of said adjacent area | region in a predetermined range by varying the composition of the composition for polishing layers is demonstrated.

(Polishing layer composition preparation step)
In the polishing layer composition preparation step, a solution in which the polishing layer composition containing the abrasive grains 21 and the binder 22 thereof is dispersed in a solvent is prepared as a coating liquid. The solvent can be the same as the solvent described in the method based on the number of times of printing.

  In this method, two types of compositions for polishing layers having different compositions are prepared. That is, the composition of the polishing layer composition used in two regions (region X1 and region X3 and region X2 and region X4) having different average heights is changed. Specifically, a polishing layer composition having a high solid content concentration is prepared as a polishing layer composition used for printing two regions having a large average height, and polishing used for printing two regions having a small average height. A polishing layer composition having a low solid content concentration is prepared as a layer composition. Thus, the average height of the polishing layer 20 formed by the same number of times of printing can be changed for each region by changing the composition for the polishing layer according to the region to be printed.

(Printing process)
Next, in the printing step, the polishing layer is applied to two regions in which the surface side of the base film 10 is divided along the polishing direction using the coating liquid prepared in the polishing layer composition preparation step. The composition for printing is printed. The mask and printing method to be used can be the same as the method based on the number of times of printing.

  In the above printing process, the composition for polishing layer having a high solid content concentration using a mask for printing only in the reference region and the polishing layer having a low solid content concentration using a mask for printing only in the low height region are used. The composition is printed separately. At this time, since the solid content concentration of the composition for the polishing layer used for printing in the reference region is high, the average height of the polishing layer 20 in the reference region can be increased. In this case, the number of times of printing in the reference area may be the same as the number of times of printing in the low height area. In this way, by making the composition of the polishing layer composition different, the difference in the reference height between the pair of adjacent regions is adjusted within a predetermined range.

(Adhesive layer application process)
Finally, in the adhesive layer attaching step, the adhesive layer 30 can be attached to the back surface of the base film 10 to obtain the polishing pad 1.

<Advantages>
In the polishing pad 1, since the polishing layer 20 is divided along the polishing direction and has a plurality of types of regions having different average heights, the workpiece is changed from a region having a small height to a region having a high height during polishing or vice versa. Polishing while moving in the direction. By setting the height difference within the above range, the gripping force of the polishing pad 1 is improved by the resistance to overcoming, and the surface pressure is increased in a region where the height is large. As a result, the polishing pad 1 can more effectively utilize the surface pressure during polishing, and therefore has a high leveling accuracy and the polishing rate is unlikely to decrease over a relatively long period of time. Therefore, since the polishing pad 1 does not need to be dressed frequently, the running cost can be reduced and the process management can be simplified.

  Therefore, the polishing pad 1 is suitably used for single-side or double-side polishing of a flat substrate including a glass substrate.

  Moreover, the manufacturing method of the said polishing pad 1 has several types of area | regions from which average height differs by making the frequency | count of printing corresponding to each area | region or the composition of the composition for polishing layers differ in a printing process, and it adjoins. The polishing pad 1 in which the difference in the reference height between the pair of regions is within the above range can be manufactured easily and reliably.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

<Polishing pad>
The said polishing pad 2 shown in FIG. 3 is disk shape, and is provided with the base film 11 and the polishing layer 20 laminated | stacked on this surface side. The polishing pad 2 includes an adhesive layer 30 that is laminated on the back side of the base film 11. Further, the polishing pad 2 includes a support 40 that is stacked via the adhesive layer 30 and a support adhesive layer 41 that is stacked on the back side of the support 40. In addition, the same component as 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

(Base film)
The base film 11 is a plate-like member for supporting the polishing layer 20. The base film 11 is divided into a region X1, a region X2, a region X3, and a region X4 along the polishing direction.

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

(Support)
The support 40 is a plate-like member for supporting the base film 11 and fixing the polishing film 2 to a polishing apparatus.

  Examples of the material of the support 40 include thermoplastic resins such as polypropylene, polyethylene, polytetrafluoroethylene, and polyvinyl chloride, and engineering plastics such as polycarbonate, polyamide, and polyethylene terephthalate. By using such a material for the support 40, the support 40 has flexibility, the polishing pad 2 follows the surface shape of the work body, and the polishing surface and the work body come into contact with each other. Since it becomes easy, polishing efficiency improves.

  The average thickness of the support 40 can be, for example, 0.5 mm or more and 2 mm or less. 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 attach the support 40 to a polishing apparatus or the flexibility of the support 40 may be insufficient.

(Support adhesive layer)
The support adhesive layer 41 is a layer for mounting the support 40 to the polishing apparatus.

  The kind and average thickness of the adhesive of the support adhesive layer 41 can be the same as those of the adhesive layer 30.

<Polishing pad manufacturing method>
The polishing pad 2 includes a step of preparing a polishing layer composition, a step of printing the polishing layer composition on the surface side of the base film 11, a step of fixing the base film 11 to the support 40, and a support. It can be manufactured by a process of applying the adhesive layer 41.

(Polishing layer composition preparation step)
Since the polishing layer composition preparation step is the same as the polishing layer composition preparation step in the first embodiment, a description thereof will be omitted.

(Printing process)
Next, in the printing step, the polishing layer composition is printed in two regions using the coating liquid prepared in the polishing layer composition preparation step.

  Specifically, two base film 11 is prepared for each region. A mask corresponding to the substrate film 11 is prepared, and the polishing layer composition is printed through the mask. The mask has a shape corresponding to the shape of the groove 23 in order to form the groove 23. The printing method can be the same as in the first embodiment. Moreover, when performing the said printing, the reference | standard height of the grinding | polishing layer 20 formed on two base film by changing the frequency | count of printing or the composition of the composition for grinding | polishing layers similarly to 1st Embodiment. The difference is adjusted to be within a predetermined range.

(Base film pasting process)
Next, in the base film pasting step, the base film 11 on which the polishing layer 20 is formed is cut so as to match the shape of each region, and is bonded to the support 40 via the adhesive layer 30.

(Support adhesive layer application process)
Finally, in the support adhesive layer applying step, the support adhesive layer 41 is attached to the back surface of the support 40 to obtain the polishing pad 2.

<Advantages>
When the polishing pad 2 includes the support body 40, the polishing pad 2 can be easily handled.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be implemented in a mode in which various changes and improvements are made in addition to the above-described mode.

  In the above embodiment, the case where the polishing pad has a disk shape has been described, but the shape of the polishing pad is not limited to a disk shape. For example, the polishing pad can be rectangular. Although it does not specifically limit as a magnitude | size when making a polishing pad into a square shape, For example, it can be set as the square shape whose one side is 140 mm or more and 160 mm or less.

  In the above-described embodiment, the polishing unit is configured in the form of a regular grid. However, the grid may not be spaced at regular intervals. For example, the pitch may be changed between the vertical direction and the horizontal direction. However, when the intervals between the polishing parts are different, anisotropy may occur in the polishing, and therefore equal intervals are preferable. The planar shape of the polishing portion may not be a lattice shape, and may be, for example, a shape in which a polygon other than a quadrangle is repeated, a circular shape, or a shape having a plurality of parallel lines. These shapes may be arranged irregularly.

  In the above embodiment, the bottom surfaces of the plurality of grooves are the surface of the base film, but the depth of the grooves is smaller than the average thickness of the polishing layer, and the grooves reach the surface of the base film. Not necessary. In that case, the depth of the groove can be 50% or more of the average thickness of the polishing layer. When the depth of the groove is less than the above lower limit, the groove may be lost due to wear, and the polishing pad may be inferior in durability.

  The polishing layer may not have a groove. The polishing layer may have a groove only between the regions.

  In the above embodiment, the polishing pad composed of two types of regions composed of the reference region and the low height region has been described. However, the number of regions having different average heights is not limited to two, and the average height is The number of different areas may be three or more.

  In the above-described embodiment, the case where a plurality of types of regions are alternately arranged along the polishing direction has been described. However, the plurality of types of regions may not be arranged along the polishing direction. Moreover, the arrangement | positioning does not need to be alternate.

  In the above embodiment, the case where the polishing layer is divided into four as regions is described, but the number of divisions is not limited to four, and may be two, three, or five or more.

  Further, it is not essential that the plurality of regions are arranged at substantially equal angular intervals, and a polishing pad in which the plurality of regions are arranged at irregular intervals is also intended by the present invention.

  Although the case where the polishing pad has an adhesive layer has been described in the first embodiment, the adhesive layer is not an essential constituent element and can be omitted. For example, the adhesive layer may be on the support side, or may be fixed to the support using other fixing means such as screwing.

  The use of the polishing pad is not limited to polishing a glass substrate. For example, the polishing pad is used for polishing difficult polishing materials that require high planarization accuracy and processing efficiency in which the polishing rate is unlikely to decrease, as with a glass substrate. It can also be used. Examples of such a hard-polishing material include sapphire substrates, compound semiconductor substrates such as GaN and SiC, and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, the said invention is not limited to a following example.

<Grinding of glass substrate>
[Comparative Example 1]
Epoxy resin ("JER1001" from Mitsubishi Chemical Corporation), diluting solvent (Isophorone), curing agent ("Ricacid MH700" from Shin Nippon Chemical Co., Ltd.), appropriate amount of curing catalyst, and diamond abrasives ("LS series" from Lands) And an average particle size of 14 μm) was added and mixed to prepare a coating solution with a diamond abrasive grain content of 50% by mass with respect to the polishing layer.

  A PET film having an average thickness of 75 μm (“Melinex S” from Teijin DuPont Films Ltd.) was prepared as a base film. This base film has an annular shape and has an outer diameter of 290 mm and an inner diameter of 103 mm.

  A polishing layer pattern was formed on the surface of the base film by a printing method. In addition, the grinding | polishing part divided | segmented by the groove | channel in the grinding | polishing layer was formed by using the mask corresponding to a grinding | polishing part as a printing pattern. The polishing part had a square shape with a side of 1.5 mm in plan view and the groove part had a width of 1.0 mm, so that the area occupation ratio of the polishing part with respect to the entire polishing layer was 36%.

  The polishing layer pattern after the printing step was dried at a temperature of 120 ° C. for 3 minutes or more, and then cured at a temperature of 120 ° C. for 16 hours or more and 20 hours or less.

  Further, a hard vinyl chloride resin plate having an average thickness of 1 mm and a circular shape in plan view (“SP770” from Takiron Co., Ltd.) is used as a support fixed to the polishing apparatus, and the back surface of the base film and the front surface of the support Were bonded with an adhesive having an average thickness of 130 μm. A double-sided tape (“# 5605HGD” from Sekisui Chemical Co., Ltd.) was used as the adhesive material. In this way, a polishing pad of Comparative Example 1 was obtained.

Example 1
First, a first base film having a polishing layer formed in the same manner as in Comparative Example 1 was prepared. Next, the addition amount of the diluting solvent (isophorone) was increased, the content of the diamond abrasive grains with respect to the polishing layer was adjusted to 42 mass%, and a polishing layer was formed in the same manner as in Comparative Example 1 using the coating solution. A second base film was prepared. Since the coating liquid is diluted, the average height of the polishing layer region of the second base film is smaller than the average height of the polishing layer of the first base film.

  Finally, the support is divided into four regions that are divided by two straight lines that pass through the center of the support, and two types of substrate films along the circumferential direction (polishing direction) with respect to the four regions. Was cut so as to match the above-mentioned region, and bonded alternately to obtain the polishing pad of Example 1. The difference in the reference height of the polishing pad of Example 1 is as shown in Table 1.

(Examples 2 and 3 and Comparative Example 2)
First, a first base film was prepared in the same manner as in Example 1. Next, the same coating liquid as the first base film of Example 1 was used as the coating liquid, and the second base film was prepared by reducing the number of printings of the polishing layer from Example 1. The number of times of printing of the second base film is -2 times in Example 2, -3 times in Example 3, and -4 times in Comparative Example 2 with reference to Example 1.

  Using the prepared first and second substrate films, polishing pads of Examples 2, 3 and Comparative Example 2 were obtained in the same manner as in Example 1. The difference in the reference heights of the polishing pads of Examples 2 and 3 and Comparative Example 2 is as shown in Table 1.

Example 4
The support was divided into eight areas of equal area by a straight line passing through the center of the support. The polishing pad of Example 4 in the same manner as in Example 3 except that two types of substrate films were cut along the circumferential direction with respect to the above 8 regions so as to match the above regions and were alternately bonded. Got. The difference in the reference height of the polishing pad of Example 4 is as shown in Table 1.

[Polishing conditions]
The glass substrate was polished using the polishing pads obtained in Examples 1 to 4 and Comparative Examples 1 and 2. As the glass substrate, soda lime glass (manufactured by Hiraoka Special Glass Manufacturing Co., Ltd.) having a diameter of 6.25 cm and a specific gravity of 2.4 was used. A commercially available double-side polishing machine (“EJD-5B-3W” from Nippon Engis Co., Ltd.) was used for the polishing. The carrier of the double-side polishing machine is an epoxy glass having a thickness of 0.6 mm. Polishing was performed 6 times in 15 minutes with a polishing pressure of 150 g / cm ² and an upper surface plate rotation speed of 60 rpm, a lower surface plate rotation speed of 90 rpm, and a SUN gear rotation speed of 30 rpm. At that time, 120 cc of “Tool Mate GR-20” manufactured by Moresco Co., Ltd. was supplied as a coolant.

[Evaluation method]
For the glass substrates polished using the polishing pads of Examples 1 to 4 and Comparative Examples 1 and 2, the polishing rate and the finished roughness of the workpiece after polishing were determined. The results are shown in Table 1.

(Polishing rate)
The polishing rate was calculated by dividing the weight change (g) of the substrate before and after polishing by the surface area (μm ² ), specific gravity (g / μm ³ ) of the substrate, and polishing time (min) for each polishing.

(Finished roughness)
For the finished roughness of Examples 1 to 4 and Comparative Examples 1 and 2, a contact-type surface roughness meter (“S-3000” from Mitutoyo Corporation) was used to measure any three locations on the front and back surfaces, The average value of a total of 6 places was calculated.

  In Table 1, “−” of the difference in reference height means that there is only one region and is not defined. Further, in the polishing according to Comparative Example 2, the edge chipping and cracking of the substrate occurred, and the polishing rate could not be measured.

  From Table 1, the polishing pads of Examples 1 to 4 have a lower finish roughness and less decrease in the polishing rate in polishing the glass substrate than the polishing pads of Comparative Examples 1 and 2. On the other hand, since the polishing pad of Comparative Example 1 does not have regions with different average heights, it is considered that the polishing rate was lowered in the fourth and subsequent polishing. Further, the polishing pad of Comparative Example 2 has a difference in reference height of 105 μm, which is 100 μm or more, and the resistance to climb over is too large.

  As a result of the above polishing of the glass substrate, polishing of Examples 1 to 4 has a plurality of types of regions having different average heights of the polishing layer, and the difference in reference height between a pair of adjacent regions is within a predetermined range. The pad has high planarization accuracy, and the polishing rate is difficult to decrease over a relatively long period of time.

  The polishing pad of the present invention has high planarization accuracy, and the polishing rate is difficult to decrease over a relatively long period of time. Therefore, the said polishing pad is used suitably for the single-sided or double-sided grinding | polishing of planar substrates including a glass substrate.

DESCRIPTION OF SYMBOLS 1, 2 Polishing pad 10, 11 Base film 20 Polishing layer 21 Abrasive grain 22 Binder 23 Groove 24 Polishing part 30 Adhesive layer 40 Support body 41 Support body adhesive layer X1, X2, X3, X4 area | region

Claims (6)

A polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof,
The polishing layer is divided along the polishing direction, and has a plurality of regions having different average heights,
When the average value of the maximum height of the polishing layer in a plurality of divided portions according to the distance from the center of gravity of the entire polishing layer for each region is set as the reference height of the region, the reference height of the pair of adjacent regions difference Ri 100μm less der than 5 [mu] m,
The surface of the polishing layer is divided by grooves,
One of the said groove | channels is arrange | positioned so that it may correspond with the boundary which divides | segments an area | region, The polishing pad characterized by the above-mentioned . A polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof,
A disc-shaped one,
The polishing layer is divided along the polishing direction, and has a plurality of regions having different average heights,
When the average value of the maximum height of the polishing layer in a plurality of divided portions according to the distance from the center of gravity of the entire polishing layer for each region is set as the reference height of the region, the reference height of the pair of adjacent regions difference Ri 100μm less der than 5 [mu] m,
A polishing pad, wherein the plurality of regions are arranged at substantially equal angular intervals . Said plurality of kinds of areas, and the reference area, consists of a low-level-area average height is less of the polishing layer from the reference area, claims are arranged alternately along the polishing direction 1 or claim 2 The polishing pad described in 1. 4. The polishing pad according to claim 1, wherein the polishing layer has a plurality of polishing portions that are arranged at substantially equal density and have a fixed shape in plan view. A method for producing a polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof,
The polishing layer has a surface divided by grooves,
One of the grooves is arranged to coincide with a boundary dividing the region;
A step of printing a composition for a polishing layer containing abrasive grains and a binder material for each of a plurality of regions divided on the surface side of the base film along the polishing direction;
When the average value of the maximum height of the polishing layer in a plurality of divided portions according to the distance from the center of gravity of the entire polishing layer for each region is used as the reference height of the region, the number of printings in the printing step or for the polishing layer A method for producing a polishing pad, characterized in that a difference in reference height between a pair of adjacent regions is adjusted to 5 μm or more and less than 100 μm by changing the composition of the composition. A method for producing a polishing pad comprising a base film and a polishing layer laminated on the surface side of the base film and containing abrasive grains and a binder thereof,
The polishing pad is disk-shaped,
The plurality of types of regions are arranged at substantially equal angular intervals,
A step of printing a composition for a polishing layer containing abrasive grains and a binder material for each of a plurality of regions divided on the surface side of the base film along the polishing direction;
When the average value of the maximum height of the polishing layer in a plurality of divided portions according to the distance from the center of gravity of the entire polishing layer for each region is used as the reference height of the region, the number of printings in the printing step or for the polishing layer A method for producing a polishing pad, characterized in that a difference in reference height between a pair of adjacent regions is adjusted to 5 μm or more and less than 100 μm by changing the composition of the composition.

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