TWI689380B - Polishing pad and manufacturing method of polishing pad - Google Patents

Abstract

The polishing pad of the present invention includes a base film; and a polishing layer, which is laminated on the surface side of the base film and contains abrasive particles and a binder, the polishing layer has different average heights divided along the polishing direction A variety of areas, when the average value of the maximum height of the polishing layer in the divided portions corresponding to the distance from the center of gravity of the entire polishing layer of each area is set as the reference height of the area, the reference of the adjacent pair of areas The difference in height is 5 μm or more and less than 100 μm. The various regions include a reference region and a low-height region whose average height with the polishing layer is smaller than the reference region, and can be alternately arranged along the polishing direction. The polishing layer may have a plurality of polishing portions arranged in a substantially equal density and having a certain shape in plan view.

Description

Polishing pad and manufacturing method of polishing pad

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

In recent years, the precision of electronic devices such as hard disks has continued to develop. As substrate materials for such electronic devices, glass is often used in consideration of rigidity, impact resistance, and heat resistance that can cope with miniaturization or thinning. The glass substrate is a brittle material, and is significantly damaged and mechanically damaged due to surface scratches. Therefore, in the polishing of such a substrate (object to be cut), processing efficiency and flattening accuracy with few scratches are required.

Generally, if the flattening accuracy of finishing is to be improved, the processing time tends to become longer, and the processing efficiency and the flattening accuracy have a trade-off relationship. Therefore, it is difficult to balance processing efficiency and flattening accuracy. On the other hand, in order to balance processing efficiency and flattening accuracy, there has been proposed a polishing pad having a polishing layer containing a binder and abrasive grains, and the polishing layer having a polishing portion (refer to Japanese Patent No. 2002-542057 Bulletin).

However, when such a conventional polishing pad is polished for a certain period of time, the polishing rate is reduced due to the wearing of abrasive grains or clogging of the surface of the polishing layer. In order to regenerate this reduced polishing rate, the surface of the polishing pad is shaved to expose a new surface to the surface, and so-called dressing is required. In that Before and after dressing, the polishing pad also needs to be cleaned. This dressing is a time-consuming operation. Since the polishing of the glass substrate is interrupted between the dressings, the polishing efficiency of the conventional polishing pad is greatly reduced due to the dressing.

[Prior Art Literature] [Patent Literature]

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

The present invention is made in view of such an inconvenience, and its object is to provide a polishing pad having high flattening accuracy and having a relatively low polishing rate over a relatively long period.

The invention made in order to solve the above problem is a polishing pad including a base film; and an abrasive layer laminated on the surface side of the base film and containing abrasive grains and its binder, the abrasive layer having A plurality of regions with different average heights divided by the polishing direction, when the average value of the maximum height of the polishing layer in the plurality of divided portions corresponding to the distance from the center of gravity of the entire polishing layer of each of the regions is defined as In the reference height of this area, the difference between the reference heights of a pair of adjacent areas is 5 μm or more and less than 100 μm.

The polishing pad has a plurality of regions with different average heights divided along the polishing direction. Therefore, during polishing, the workpiece is moved from a small height region to a large region or in the opposite direction. Grind. By putting The height difference is set within the above range, and the gripping force of the polishing pad is increased by its running resistance, and the surface pressure is increased in a region with a large height. Thus, the polishing pad can more effectively utilize the surface pressure during polishing, so it has high flattening accuracy, and the polishing rate is not likely to decrease over a relatively long period of time. Therefore, the polishing pad does not need to be trimmed frequently, so that the running cost can be reduced or the step management can be simplified.

The polishing pad is disk-shaped, and the plurality of regions can be arranged at substantially equal angular intervals. Polishing of glass substrates and the like is usually performed by rotating the polishing pad while contacting the workpiece. Therefore, by using a disc-shaped one and arranging a plurality of regions at substantially equal angular intervals, the shaved body periodically moves between the regions, so that a higher flattening accuracy and a reduction effect of a reduction in the polishing rate can be further obtained.

The various regions include a reference region and a low-height region whose average height with the polishing layer is smaller than the reference region, and can be alternately arranged along the polishing direction. By alternately arranging two types of regions with different average heights in this manner, it is possible to maintain high flattening accuracy and a suppression effect of a reduction in polishing rate, and suppress an increase in the manufacturing cost of the polishing pad.

The polishing layer may have a plurality of polishing portions arranged in a substantially equal density and having a certain shape in plan view. In this way, the polishing portions of a certain shape are arranged at a substantially equal density, and the polishing portions are regularly arranged, so that the surface pressure or the number of polishing action points on the workpiece to be polished can be easily controlled, so the flattening accuracy is further improved .

Therefore, the polishing pad can be preferably used for a plane represented by a glass substrate Polishing of substrates.

Another invention made to solve the above problem is a method of manufacturing a polishing pad, which is a method of manufacturing a polishing pad including a substrate film; and a polishing layer stacked on the surface side of the substrate film And contains abrasive grains and their binders, and the method of manufacturing the polishing pad includes printing the composition for the polishing layer containing the abrasive grains and their binder materials on the surface side of the base film along the direction of polishing For each of the various regions into which the average height of the polishing layer in the multiple divided parts corresponding to the distance from the center of gravity of the entire polishing layer of each of the regions is set as the reference height of the region In this case, the difference between the reference heights of the adjacent pair of regions is adjusted to 5 μm or more and less than 100 μm by changing the number of prints in the printing step or the composition of the polishing layer composition.

With regard to the manufacturing method of this polishing pad, by making the number of printings corresponding to each area in the printing step or the composition of the composition for the polishing layer different, it is possible to easily and reliably manufacture a pair of adjacent areas having multiple areas with different average heights The difference in the reference height of the area is the polishing pad within the range.

Here, the "average height of the polishing layer" refers to, for example, the height of the polishing layer from the average interface of the base film measured using a laser displacement meter ("LJV7020" of KEYENCE). average value. The so-called "multiple areas with different average heights" refer to areas with a deviation of less than 3% from the average height as one area, and multiple areas with different average heights. In addition, the "multiple divided portions corresponding to the distance from the center of gravity of the entire polishing layer" means that when the shortest distance from the center of gravity of the entire polishing layer to the region is X [mm], the longest distance When set to Y[mm], the distance from the center of gravity of the entire polishing layer is divided into X[mm] or more and less than (X+1/n(YX))[mm], (X+1/n(YX)) [mm] or more and less than (X+2/n(YX))[mm], ... (X+(n-1)/n(YX)) [mm] or more and n parts below Y[mm]. Here, n is an integer of 2 or more, for example, n=3.

The so-called "area with approximately equal angles" means that the difference between the minimum and maximum angles formed by the radiation connecting the center of the disc and the centers of each area is 10° or less. The so-called "approximately equal density of the polished portion" is It means that the deviation of the interval between the plurality of polishing sections and the deviation of the area are within 10% of the average value, respectively. In addition, the "polishing direction" refers to the direction in which the polishing pad moves during polishing. For example, if it is a disc-shaped polishing pad, it refers to the circumferential direction.

As described above, the polishing pad of the present invention has high planarization accuracy, and the polishing rate is not likely to decrease over a relatively long period of time. Therefore, the polishing pad does not need to be trimmed frequently, so that the running cost can be reduced or the step management can be simplified.

1, 2: grinding pad

10, 11: substrate film

20: Grinding layer

21: abrasive grain

22: Adhesive

23: slot

24: Grinding Department

30: then layer

40: Support

41: Support layer

X1, X2, X3, X4: area

FIG. 1A is a schematic plan view showing a polishing pad according to an embodiment of the present invention.

FIG. 1B is a schematic cross-sectional view taken along line A-A of FIG. 1A.

2 is a schematic cross-sectional view showing a polishing pad of an embodiment different from FIG. 1B.

[First embodiment]

Hereinafter, the first embodiment of the present invention will be described in detail with appropriate reference to the drawings.

<grinding pad>

The polishing pad 1 shown in FIGS. 1A and 1B is disk-shaped, and mainly includes a base film 10 and a polishing layer 20 deposited on the surface side thereof. In addition, the polishing pad 1 includes an adhesive layer 30 laminated on the back side of the base film 10.

(Substrate film)

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

The material of the base film 10 is not particularly limited, and examples thereof include polyethylene terephthalate (Polyethylene Terephthalate (PET), polypropylene (Polypropylene, PP), polyethylene (Polyethylene, PE), and polyethylene). Polyimide (PI), polyethylene naphthalate (PEN), aromatic aramid, aluminum, copper, etc. Among them, PET and PI with good adhesion to the polishing layer 20 are preferable. In addition, the surface of the base film 10 may be subjected to a treatment such as chemical treatment, corona treatment (primer treatment), or primer treatment to improve adhesion.

The size of the base film 10 is not particularly limited, and for example, it can be a circular ring having an outer diameter of 270 mm or more and 320 mm or less and an inner diameter of 80 mm or more and 130 mm or less.

The average thickness of the base film 10 is not particularly limited. For example, it can be made 75 μm or more and 1 mm or less. When the average thickness of the base film 10 is less than the lower limit, the polishing pad 1 may have insufficient strength or flatness. another On the one hand, when the average thickness of the base film 10 exceeds the upper limit, the polishing pad 1 may become unnecessarily thick and may be difficult to handle.

(Grinding layer)

The polishing layer 20 contains abrasive particles 21 and its adhesive 22. 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 X2 and X4 having different average heights. In addition, the polishing layer 20 has a plurality of grooves 23 on the surface.

The average thickness of the polishing layer 20 (the average thickness of the removal groove 23) is not particularly limited, and the lower limit of the average thickness of the polishing layer 20 is preferably 25 μm, more preferably 30 μm. In addition, 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 may become unnecessarily thick and difficult to handle.

(Grinding grain)

Examples of the abrasive particles 21 include particles such as diamond, alumina, and silica. Among them, diamond abrasive grains with high polishing efficiency are preferred.

The lower limit of the average particle diameter of the abrasive particles 21 is preferably 3 μm, and more preferably 10 μm. In addition, the upper limit of the average particle diameter of the abrasive particles 21 is preferably 15 μm, and more preferably 14 μm. When the average particle diameter 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 size of the abrasive grains 21 exceeds the upper limit, the object to be shaved may be damaged. Yu.

The lower limit of the content of the polishing particles 21 relative to the polishing layer 20 is preferably 35% by volume, and more preferably 40% by volume. In addition, the upper limit of the content of the polishing particles 21 relative to the polishing layer 20 is preferably 70% by volume, and more preferably 65% by volume. When the content of the polishing particles 21 with respect to the polishing layer 20 is less than the lower limit, the polishing force of the polishing layer 20 may be insufficient. On the other hand, when the content of the polishing particles 21 with respect to the polishing layer 20 exceeds the upper limit, there is a possibility that the workpiece is damaged.

(Binder)

The composition constituting the adhesive 22 is not particularly limited, and a thermosetting resin can be used as a main component. Examples of thermosetting resins include polyurethane, polyphenol, epoxy, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacrylic acid, acrylate, polyvinyl alcohol, polyvinyl chloride, poly Vinyl acetate, polyamide, etc. Among these, thermosetting epoxy is preferred. When the thermosetting epoxy constitutes the adhesive 22, it is easy to ensure good dispersibility of the abrasive grains 21 and good adhesion to the base film 10. Here, the “main component” refers to the component with the largest content, for example, the component with a content of 50% by mass or more.

An inorganic substance can be used as the main component of the adhesive 22. Examples of such an inorganic substance include silicate, phosphate, and polyvalent metal alkoxide. Among them, silicate having a high abrasive particle holding power of the polishing layer 20 is preferable.

The adhesive 22 may also contain a dispersant, a coupling agent, a surfactant, a lubricant, a defoaming agent, a coloring agent, etc. as appropriate according to the purpose Various additives and additives. In addition, at least a part of the resin of the adhesive 22 may be cross-linked.

(groove)

The surface of the polishing layer 20 has a plurality of polishing portions 24 divided by grooves 23. The bottom surface of the groove 23 that defines the polishing portion 24 is constituted by the surface of the base film 10. In addition, the grooves 23 are arranged in a grid pattern at regular intervals on the surfaces of the regions X1, X2, X3, and X4 of the polishing layer 20. That is, the polishing portion 24 has a certain shape in plan view, and is arranged at a substantially equal density. By arranging the polishing portions 24 of a certain shape at a substantially equal density in this way, it is possible to easily control the surface pressure of the object to be polished or the number of polishing action points, and the flattening accuracy is further improved.

The lower limit of the average width of the groove 23 is preferably 0.3 mm, and more preferably 0.5 mm. In addition, 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 smaller than the lower limit, there is a possibility that the grinding powder caused by the grinding may block the groove 23. On the other hand, when the average width of the groove 23 exceeds the upper limit, there is a risk of damage to the workpiece during polishing.

The lower limit of each average area of the polishing section 24 is preferably 1 mm ² , and more preferably 2 mm ² . In addition, the upper limit of the average area of the polishing section 24 is preferably 150 mm ² , and more preferably 130 mm ² . When the average area of the polishing section 24 is less than the lower limit, the polishing section 24 may peel off from the base film 10. On the other hand, when the average area of the polishing section 24 exceeds the upper limit, there is a possibility that the area of contact of the polishing layer 20 with the workpiece to be polished during polishing may decrease the polishing efficiency.

The lower limit of the area occupancy of the plurality of polishing portions 24 with respect to the entire polishing layer 20 is preferably 20%, and more preferably 30%. In addition, the upper limit of the area occupancy of the plurality of polishing sections 24 with respect to the entire polishing layer 20 is preferably 60%, and more preferably 55%. When the area occupancy of the plurality of polishing portions 24 with respect to the entire polishing layer 20 is less than the lower limit, there is a possibility that the control of the surface pressure of the object to be polished or the number of polishing action points becomes ineffective. It is sufficient, so it is not possible to obtain sufficient flattening accuracy. On the other hand, when the area occupancy of the plurality of polishing portions 24 with respect to the entire polishing layer 20 exceeds the upper limit, the friction resistance at the time of polishing of the polishing layer 20 may increase and the object to be cut may be damaged Worry. In addition, when the polishing layer has a groove, the “area of the entire polishing layer” is a concept including the area of the groove.

(Abrasive layer area)

The two types of regions X1 and X3 and X2 and X4 include the reference region X1 and X3, and the average height of the polishing layer 20 is lower than the reference region X1 and the low-level region X2 and region X3, and along the polishing direction Alternately allocated. In addition, each area is divided by two straight lines that pass through the center of the ring of the polishing layer 20 and are orthogonal. That is, the regions X1, X2, X3, and X4 are arranged at substantially equal angular intervals. By arranging the two types of regions at substantially equal angular intervals in this way, the object to be shaved periodically moves between the regions, so that it is possible to further obtain a high flattening accuracy and a suppression effect of a reduction in the polishing rate.

In addition, one of the grooves 23 may coincide with the boundary of the divided area Way allocation. By making one of the grooves 23 coincide with the boundary, and the step difference between the regions faces each other across the groove 23, the groove 23 becomes a buffer area and can suppress the occurrence of edge or breakage of the cut object.

The lower limit of the difference in the reference height between the region and the adjacent region (for example, the difference in reference height between X1 and X2) is 5 μm, more preferably 20 μm, and still more preferably 40 μm. In addition, the difference in the reference heights of the regions is less than 100 μm, more preferably less than 90 μm, and even more preferably less than 80 μm. When the difference in the reference height of the area is less than the lower limit, since the running resistance is reduced, the effect of improving the gripping force due to the running resistance may be insufficient. Conversely, when the difference in the reference height of the area is equal to or greater than the upper limit, the running resistance is too large, so there is a risk of chipping or cracking of the workpiece.

(Next layer)

Next, the layer 30 is a layer that fixes the polishing pad 1 on a support body, and the support body is used to support the polishing pad 1 and install it 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 as the adhesive layer 30 is preferably an adhesive. By using an adhesive as the adhesive used in the adhesive layer 30, the polishing pad 1 can be peeled off from the support and reattached, so that the polishing pad 1 and the support can be easily reused. The adhesive is not particularly limited, and examples thereof include acrylic adhesives, acrylic-rubber adhesives, natural rubber adhesives, synthetic rubber adhesives such as butyl rubber adhesives, silicone adhesives, and polyadhesives. Carbamate adhesives, etc.

The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, and more preferably 0.1 mm. In addition, the upper limit of the average thickness of the adhesive layer 30 is preferably 0.3 mm, and 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 polishing pad 1 may peel off from the support. On the other hand, when the average thickness of the adhesive layer 30 exceeds the upper limit, for example, the thickness of the adhesive layer 30 may cause a decrease in workability such as an obstacle when the polishing pad 1 is cut into a desired shape. .

The lower limit of the ratio of the polishing rate of the polishing layer 20 during the fifth polishing to the polishing rate in the first polishing is preferably 90%, more preferably 95%, and still more preferably 99%. When the ratio of the polishing rate is less than the lower limit, the polishing efficiency may be lowered due to the decrease in the polishing rate. Here, the "grinding rate" refers to sodium with a diameter of 6.25 cm and a specific gravity of 2.4 under the conditions of a grinding pressure of 150 g/cm ² , an upper platen rotation of 60 rpm, a lower platen rotation of 90 rpm, and a sun gear rotation of 30 rpm. The grinding rate of each time when the lime glass is repeatedly ground for 15 minutes. Specifically, the polishing rate is calculated 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).

<Manufacturing method of polishing pad>

The polishing pad 1 can be manufactured by the following steps: 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 film 10; and a step of attaching an adhesive layer 30. With regard to this polishing pad 1, the difference between the reference heights of the adjacent pair of the regions is adjusted to be within a predetermined range by varying the number of printings in the printing step or the composition of the composition for the polishing layer. Below, the two methods Be explained.

[Method according to printing times]

First, a method of manufacturing the polishing pad 1 by adjusting the difference in the reference height of a pair of adjacent regions to be within a predetermined range by changing the number of prints will be described.

(Preparation step of composition for polishing layer)

First, in the preparation step for the polishing layer composition, a solution obtained by dispersing the polishing layer composition containing the abrasive grains 21 and the binder 22 in a solvent is prepared as a coating liquid. The solvent is not particularly limited as long as it can dissolve the material forming the adhesive 22. Specifically, methyl ethyl ketone (Methyl Ethyl Ketone (MEK), isophorone, terpineol, N-methylpyrrolidone, cyclohexanone, propylene carbonate), or the like can be used. In order to control the viscosity or fluidity of the coating liquid, diluents such as water, alcohol, ketone, acetate, aromatic compounds, etc. may also be added.

(Printing steps)

Next, in the printing step, using the coating liquid prepared in the polishing layer composition preparation step, the polishing layer composition is printed on the surface side of the base film 10 and divided along the polishing direction On two areas. Specifically, the surface of the base film 10 is divided such that two types of regions are alternately arranged along the polishing direction. That is, a mask corresponding to these two areas is prepared, and the composition for the polishing layer is printed via the mask. In addition, in order to form the groove 23, the mask has a shape corresponding to the shape of the groove 23.

As this printing method, for example, screen printing or metal mask printing can be used Wait. After printing, the coating liquid is dehydrated by heating and hardened by heating, thereby forming the polishing layer 20. Specifically, for example, after the coating liquid is dried at room temperature (25°C), heated and dehydrated using heat of 70°C or more and 90°C or less, and then hardened by heat of 100°C or more and 160°C or less to form an adhesive twenty two.

In the printing step, the following printings are respectively performed: printing of the composition for the polishing layer using the mask for printing only on the reference area; print. At this time, by increasing the number of printing in the reference area, the average height of the polishing layer 20 can be increased. In this way, by making the number of prints different, the difference in the reference height of the adjacent pair of the areas is adjusted to be within a predetermined range.

(Then attach the layer step)

Finally, in the adhesive layer attaching step, the adhesive layer 30 is attached to the back surface of the base film 10 to obtain the polishing pad 1.

[The method according to the composition of the polishing layer composition]

First, a method of manufacturing the polishing pad 1 in which the difference in the reference height of the pair of adjacent regions is adjusted to be within a predetermined range by making the composition of the polishing layer composition different will be described.

(Preparation step of composition for polishing layer)

In the preparation step for the polishing layer composition, a solution obtained by dispersing the polishing layer composition containing the abrasive grains 21 and the binder 22 in a solvent is prepared as a coating liquid. The solvent may be the same as described in the method according to the number of printing times.

In this method, two compositions for abrasive layers with different formulations are prepared. which is, The formulation of the polishing layer composition used in two regions (region X1 and region X3 and region X2 and region X4) with different average heights was changed. Specifically, a composition for a polishing layer with a high solid content concentration is prepared as a composition for a polishing layer used in printing of two regions with a large average height, and a composition for a polishing layer with a low solid content concentration is prepared as an average height A composition for an abrasive layer used for printing in two small areas. In this way, by changing the composition for the polishing layer corresponding to the area where printing is performed, the average height of the polishing layer 20 formed by the same number of printing times can be changed for each area.

(Printing steps)

Next, in the printing step, the coating liquid prepared in the polishing layer composition preparation step is used to print the polishing for two types of areas divided along the polishing direction on the surface side of the base film 10. Layer composition. The mask and printing method used can be the same as the method according to the number of printing times.

In the printing step, the following printings are respectively performed: printing of a composition for a polishing layer with a high solid content concentration using a mask for printing only on a reference area; and solid using a mask for printing only in a low-height area Printing of the composition for the polishing layer with a low component concentration. At this time, since the solid content concentration of the polishing layer composition used in the printing of the reference area is high, the average height of the polishing layer 20 in the reference area can be increased. In this case, the number of prints in the reference area may be the same as the number of prints in the low-height area. In this way, by making the composition of the polishing layer composition different, the difference between the reference heights of the adjacent pair of the regions is adjusted to be within a predetermined range.

(Then attach the layer step)

Finally, in the adhesive layer attaching step, the adhesive layer 30 is attached to the back surface of the base film 10 to obtain the polishing pad 1.

<Advantages>

Since the polishing layer 1 has a plurality of regions with different average heights divided along the polishing direction, the polishing pad 1 moves the surface of the workpiece from a small region to a large region or in the opposite direction during polishing One side is ground. By setting the height difference within the above range, the gripping force of the polishing pad 1 is increased by its running resistance, and the surface pressure is increased in a region with a large height. Thus, the polishing pad 1 can more effectively utilize the surface pressure during polishing, and therefore has high flattening accuracy, and the polishing rate is not likely to decrease over a relatively long period of time. Therefore, the polishing pad 1 does not need to be trimmed frequently, so that the operation cost can be reduced or the step management can be simplified.

Therefore, the polishing pad 1 can be preferably used for polishing a single side or both sides of a flat substrate represented by a glass substrate.

In addition, the manufacturing method of the polishing pad 1 can easily and reliably produce a plurality of regions having different average heights and adjacent by making the number of printings corresponding to each region in the printing step or the composition of the polishing layer composition different. The difference in the reference height of a pair of the regions is the polishing pad 1 within the range.

[Second Embodiment]

Hereinafter, the second embodiment of the present invention will be described in detail with appropriate reference to the drawings.

<grinding pad>

The polishing pad 2 shown in FIG. 2 has a disc shape, and includes a base film 11 and a polishing layer 20 deposited on the surface side thereof. In addition, the polishing pad 2 includes an adhesive layer 30 stacked on the back side of the base film 11. Furthermore, the polishing pad 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 constituent elements as those in the first embodiment are given the same symbols, and the description is omitted.

(Substrate film)

The base film 11 is a plate-shaped 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 may be the same as the base film 10 of the first embodiment.

(Support)

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

Examples of the material of the support body 40 include thermoplastic resins such as polypropylene, polyethylene, polytetrafluoroethylene, and polyvinyl chloride, engineering plastics such as polycarbonate, polyamide, and polyethylene terephthalate. (engineering plastic). By using such a material in the support body 40, the support body 40 has flexibility, the polishing pad 2 follows the surface shape of the object to be cut, and the polishing surface becomes easily contacted with the object to be cut, so the polishing to raise efficiency.

The average thickness of the support 40 can be set to, for example, 0.5 mm or more And below 2mm. 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 device or the flexibility of the support 40 may be insufficient.

(Support layer)

The support bonding 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.

<Manufacturing method of polishing pad>

The polishing pad 2 can be manufactured by the following steps: a step of preparing the composition for the polishing layer; a step of printing the composition for the polishing layer on the surface side of the base film 11; and fixing the base film 11 to the support Step 40 and the step of attaching the support adhesive layer 41.

(Preparation step of composition for polishing layer)

The procedure for preparing the composition for the polishing layer is the same as the procedure for preparing the composition for the polishing layer in the first embodiment, so the description is omitted.

(Printing steps)

Next, in the printing step, using the coating liquid prepared in the polishing layer composition preparation step, the polishing layer composition is printed on two types of regions.

Specifically, two base film 11 for each area are prepared. A mask corresponding to the base film 11 is prepared, and the composition for the polishing layer is printed through the mask. In addition, in order to form the groove 23, the mask has a shape corresponding to the shape of the groove 23 shape. The printing method may be the same as the first embodiment. In addition, when the printing is performed, the reference height of the polishing layer 20 formed on the two substrate films is changed by changing the number of prints or the composition of the polishing layer composition in the same manner as in the first embodiment. The difference is adjusted so as to be within the prescribed range.

(Steps for attaching substrate film)

Next, in the base film attaching step, the base film 11 on which the polishing layer 20 is formed is cut so as to conform to the shape of each region, and then adhered to the support 40 via the adhesive layer 30.

(Procedure for attaching the support layer)

Finally, in the step of attaching the support layer, the support layer 41 is attached to the back surface of the support 40 to obtain the polishing pad 2.

<Advantages>

Since the polishing pad 2 includes the support body 40, the operation of the polishing pad 2 becomes easy.

[Other embodiments]

The present invention is not limited to the above-mentioned embodiment, and in addition to the above-mentioned embodiment, various modifications and improvements can be implemented in the embodiment.

In the above embodiment, the case where the polishing pad is in the shape of a disk has been described, but the shape of the polishing pad is not limited to the shape of a disk. For example, the polishing pad can be made into a square shape. The size of the polishing pad in a square shape is not particularly limited, and for example, a square shape having a side of 140 mm or more and 160 mm or less can be used.

In the above-described embodiment, the polishing portions are formed in a grid pattern at equal intervals. However, the intervals between the grids may not be equal intervals. For example, the intervals may be changed in the longitudinal direction and the lateral direction. However, when the interval between the polishing sections is different, there is a possibility that anisotropy may occur during polishing, and therefore the interval is preferably equal. In addition, the planar shape of the polishing portion may not be a lattice shape, and may be, for example, a polygonal shape other than a quadrangular shape, a circular shape, or a shape having multiple parallel lines. These shapes can be arranged irregularly.

In addition, in the above embodiment, the bottom surfaces of the plurality of grooves are configured as the surface of the base film, or the depth of the grooves may be smaller than the average thickness of the polishing layer and the grooves do not reach the surface of the base . In this case, the depth of the groove portion may be 50% or more of the average thickness of the polishing layer. When the depth of the groove is less than the lower limit, the groove may disappear due to wear, and the durability of the polishing pad may be poor.

The abrasive layer may not have grooves. In addition, the polishing layer may be configured to have grooves only between regions.

In the above embodiment, the polishing pad including two types of areas including the reference area and the low-height area has been described, but the number of areas with different average heights is not limited to two, and the number of areas with different average heights may be For more than three types.

In addition, in the above embodiment, the case where a plurality of types of regions are alternately arranged along the polishing direction has been described, and the plurality of types of regions may not be arranged along the polishing direction. In addition, the arrangement may not be alternate.

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

In addition, as a result, it is not a necessary configuration element that a plurality of regions are arranged at substantially equal angular intervals, and a study of a plurality of regions arranged at irregular intervals The sanding pad is also the object of the present invention.

In the first embodiment described above, the case where the polishing pad has an adhesive layer has been described. However, the adhesive layer is not an essential component and may be omitted. For example, the adhesive layer may be located on the side of the support, and may be fixed to the support using other fixing means such as screw fastening.

In addition, the use of the polishing pad is not limited to the polishing of a glass substrate. For example, it can also be used for polishing of difficult-to-grind materials that require high planarization accuracy and processing efficiency that does not easily reduce the polishing rate, as with glass substrates. Examples of such hard-to-grind materials include compound semiconductor substrates such as sapphire substrates, GaN, and SiC.

[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.

<Grinding of glass substrates>

[Comparative Example 1]

Adding diluent solvent (isophorone), hardener (``Rikacid MH700'' of Nippon Chemical & Chemical Co., Ltd.), appropriate amount of hardening catalyst, and diamond to epoxy resin (``JER1001'' of Mitsubishi Chemical Corporation) The abrasive grains (Lands' "LS series", average particle diameter 14 μm) were mixed, and were prepared so that the content of diamond abrasive grains with respect to the polishing layer became 50% by mass to obtain a coating liquid.

As a base film, a PET film with an average thickness of 75 μm (Teijin Dupont Films Co., Ltd. “Melinex S”) was prepared. The base The material film is ring-shaped and has an outer diameter of 290 mm and an inner diameter of 103 mm.

An abrasive layer pattern is formed on the surface of the base film by a printing method. In addition, by using a mask corresponding to the polishing portion as a printed pattern, a polishing portion separated by grooves is formed in the polishing layer. The polishing portion has a square shape with a side of 1.5 mm in a plan view, and the groove portion has a width of 1.0 mm, thereby setting the area occupation ratio of the polishing portion to the entire polishing layer to 36%.

The polishing layer pattern after the printing step is 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.

In addition, a rigid vinyl chloride resin plate ("SP770" of Takiron Co., Ltd.) with an average thickness of 1 mm and a circular shape in plan view is used as a support fixed to the polishing device, and an adhesive material with an average thickness of 130 μm is used The back surface of the base film is bonded to the surface of the support. As the adhesive material, two-sided tape (Sekisui Chemical Co., Ltd. "#5605HGD") was used. The polishing pad of Comparative Example 1 was obtained in the manner described.

(Example 1)

First, in the same manner as in Comparative Example 1, the first base film on which the polishing layer is formed is prepared. Next, the second substrate film on which the polishing layer was formed was prepared in the same manner as in Comparative Example 1 by using a coating liquid that increased the amount of addition of the dilution solvent (isophorone) and used the relative amount of diamond abrasive grains. It was prepared so that the content of the polishing layer became 42% by mass. Since the coating liquid is diluted, the average height of the region of the polishing layer of the second base film is also smaller than the average height of the polishing layer of the first base film.

Finally, the support is divided into 4 areas divided by two straight lines passing through the center of the support and being orthogonal, with respect to the 4 areas, the two kinds of base film are divided in the circumferential direction (grinding direction) The polishing pad of Example 1 was obtained by cutting in such a manner as to match the area and alternately bonding. The difference in the reference height of the polishing pad of Example 1 is as shown in Table 1.

(Example 2, Example 3 and Comparative Example 2)

First, the 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 number of printing of the polishing layer was reduced compared to Example 1 to prepare a second base film. In addition, regarding the printing frequency of the second base film, based on Example 1, Example 2 is -2 times, Example 3 is -3 times, and Comparative Example 2 is -4 times.

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

(Example 4)

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

[Grinding conditions]

Using the polishing pads obtained in Examples 1 to 4 and Comparative Examples 1 and 2, the glass substrate was polished. As the glass substrate, soda lime glass (Hiraoka Special Glass Manufacturing Co., Ltd.) having a diameter of 6.25 cm and a specific gravity of 2.4 was used. For the grinding, a commercially available double-sided grinding machine ("EJD-5B-3W" of Engis Japan Co., Ltd.) was used. The carrier of the double-sided grinding machine is epoxy glass with a thickness of 0.6 mm. The polishing was performed by setting the polishing pressure to 150 g/cm ² and performing 6 times in 15 minutes under the conditions of 60 rpm of the upper platen rotation, 90 rpm of the lower platen rotation, and 30 rpm of the sun gear rotation. At this time, as a coolant, Moresco Co., Ltd.'s "Toolmate GR-20" was supplied at 120 cc per minute.

[Evaluation method]

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

(Grinding rate)

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

(Finishing roughness)

For the finishing roughness of Examples 1 to 4 and Comparative Example 1 and Comparative Example 2, a contact surface roughness meter ("S-3000" of Mitutoyo Co., Ltd.) was used to measure the surface and back The measurement was performed at three arbitrary positions, and the average value of the six positions was calculated.

In Table 1, the difference of the reference height "-" means that there is only one area, so it is not defined. In addition, according to the polishing of Comparative Example 2, defects such as chipping and cracking of the substrate occurred, and the polishing rate could not be measured.

According to Table 1, compared to the polishing pads of Comparative Examples 1 and 2, the polishing pads of Examples 1 to 4 have a low finish roughness and a small decrease in polishing rate during polishing of the glass substrate. In contrast to this, it is considered that the polishing pad of Comparative Example 1 does not have regions having different average heights, and therefore, the polishing rate decreases during the fourth and subsequent polishings. In addition, it is considered that the polishing pad of Comparative Example 2 has a difference in reference height of 100 μm or more and 105 μm, and the running resistance is excessively large, so that the glass substrate is chipped or broken.

According to the results of the above-mentioned polishing of the glass substrate, there are various regions having different average heights of the polishing layer, and the difference between the reference heights of the adjacent pair of the regions is within a predetermined range. The polishing pads of Examples 1 to 4 have High leveling Degree, and the polishing rate is not easy to decrease in a relatively long period.

[Industry availability]

The polishing pad of the present invention has high planarization accuracy, and the polishing rate is not likely to decrease over a relatively long period of time. Therefore, the polishing pad can be preferably used for polishing one or both sides of a planar substrate represented by a glass substrate.

1: Grinding pad

10: substrate film

20: Grinding layer

21: abrasive grain

22: Adhesive

23: slot

24: Grinding Department

30: then layer

X1, X2: area

Claims (6)

A polishing pad, including a substrate film; and a polishing layer, which is laminated on the surface side of the substrate film and contains abrasive particles and a binder, characterized in that the polishing layer is divided along its polishing direction For various regions with different average heights, the average value of the maximum height of the polishing layer in the plurality of divided parts corresponding to the distance of the center of gravity of the entire polishing layer for each of the regions should be used as the reference for the region At the height, the difference between the reference heights of the adjacent pair of the regions is 5 μm or more and less than 100 μm. The surface of the polishing layer is divided by grooves, and one of the grooves is arranged so as to coincide with the boundary of the divided region. The polishing pad according to item 1 of the patent application range, wherein the plurality of regions include a reference region, and the average height of the polishing layer is smaller than the low-height region of the reference region, and are alternately arranged along the polishing direction. The polishing pad according to item 1 of the patent application range, wherein the polishing layer has a plurality of polishing portions arranged in a substantially equal density and having a certain shape in plan view. The polishing pad according to item 1 of the scope of the patent application is in the form of a disk, and the plurality of regions are arranged at substantially equal angular intervals. The polishing pad as described in item 1 of the patent application scope is used for planar polishing of a substrate. A method of manufacturing a polishing pad, which is a method of manufacturing a polishing pad, the polishing pad including a substrate film; and a polishing layer, which is laminated on the surface side of the substrate film and contains abrasive particles and a binder thereof, The method of manufacturing a polishing pad is characterized by including: printing a composition for a polishing layer containing abrasive grains and a binder material on each of a plurality of regions divided along the polishing direction on the surface side of the base film Step, when the average value of the maximum height of the polishing layer in the plurality of divided portions corresponding to the distance from the center of gravity of the entire polishing layer of each of the regions is set as the reference height of the region, by using The number of printings in the printing step or the composition of the composition for the polishing layer are different, and the difference in the reference heights of the adjacent pair of the regions is adjusted to be 5 μm or more and less than 100 μm. The surface of the polishing layer is divided by grooves. One of the grooves is arranged so as to coincide with the boundary of the divided area.

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