TW201836769A - Polishing sheet and method for producing polishing sheet - Google Patents

Abstract

A polishing sheet has a sheet-form base and abrasive grains disposed so as to penetrate from one surface of the base to the other surface. The abrasive grains are preferably disposed on the one surface with the tips, which will contact the object being polished, aligned in the same plane. Preferably, the abrasive grains are disposed apart and form a single particle layer. The average diameter of the abrasive grains is preferably 2-3 times the thickness of the base. The polishing sheet can be used as dicing blades and the kerf width is preferably 1.1-1.5 times the average diameter of the abrasive grains. The abrasive grains are preferably disposed concentrically.

Description

Abrasive sheet and method for manufacturing abrasive sheet

The present invention relates to a polishing sheet and a method for manufacturing a polishing sheet, and in particular, it relates to a polishing sheet for smooth polishing the surface of various objects to be polished, such as a magnetic disk substrate, a silicon wafer, a glass substrate for a display device, or a lens, and a manufacturing method thereof. A method of polishing a sheet is even a method of manufacturing a polishing sheet that can be formed into a cutting blade that can be used to cut or groove a workpiece such as a wafer on which a semiconductor device or an electronic component is formed.

In order to polish the surface of the object to be polished smoothly and evenly, polishing is performed using abrasive grains as fine as possible. As a polishing method, there are known a free abrasive grain method in which abrasive grains are externally supplied to an object to be polished to perform polishing, and a fixed abrasive that performs polishing using a polishing sheet in which abrasive grains are fixed to a substrate sheet. Grain way. The fixed abrasive method does not require a large number of abrasive materials such as the free abrasive method, and the substrate sheet to which the abrasive material is fixed can also realize various shapes, so it is widely used. On the other hand, in recent years, a dicing blade for cutting or grooving a workpiece such as a wafer has been required for further fine processing, and a wide groove having a width of about 10 μm is required to be processed.

The abrasive flakes of the fixed abrasive method are composed of the following materials: organic resins such as polyethylene terephthalate, woven fabrics, and non-woven fabrics are selected as the substrate sheet, and inorganic materials such as alumina, silica, and diamond are used. The fine particles of the abrasive material are fixed to the substrate sheet with an adhesive such as resin.

The polishing performance of the polishing sheet is greatly influenced by the properties of the abrasive particles to be polished. In terms of the properties of the abrasive grains, the material, particle size, and shape of the abrasive grains are important factors. However, in order to make full use of the performance, in the fixed layer to which the abrasive grains are fixed, in which arrangement of the individual abrasive grains are Fixation becomes an important factor.

When the abrasive grains are agglomerated and fixed to the abrasive sheet of the substrate sheet, the surface roughness of the abrasive sheet is inconsistent, which may cause damage to the surface of the object to be polished, and it is difficult to precisely polish the object to be polished.

In particular, in order to super-precisely grind a to-be-polished body, it is not preferable to be fixed to a board | substrate sheet in the state which abraded abrasive grains agglomerated. Even if it appears that the abrasive particles are uniformly dispersed, if the microscopic observation still agglomerates, it is not ideal even in the case of clot dispersion, for example.

Therefore, in order to eliminate the occurrence of the damage as described above, Patent Document 1 discloses a polishing sheet in which the particle size of the abrasive grains is made as uniform as possible, and the abrasive grains are fixed to a single layer. The polishing sheet is provided with a cutting edge having polishing abrasive particles on the polishing sheet, and is fixed to separate and distribute the polishing abrasive particles.

A cutting device for dividing a workpiece such as a wafer on which a semiconductor device or an electronic component is formed into individual wafers includes at least: a cutting blade that is rotated at a high speed by a rotating shaft; a workpiece platform on which the workpiece is placed; The position change control device performs processing such as cutting or grooving on the workpiece by such operations. Regarding the cutting blade used in the cutting device shown above, Patent Document 2 discloses an abrasive grain having an average diamond abrasive grain diameter of 25 μm or less, which is processed into a polycrystalline diamond by sintering and processed into a disc shape. , The outer peripheral portion is processed by laser to form a cutting blade. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-131909 [Patent Document 2] Japanese Patent Laid-Open No. 2015-164228

[Problems to be Solved by the Invention]

In recent years, in order to increase the average wafer yield per wafer, the width of the margin when performing dicing called a street has gradually narrowed. Therefore, for a cutting blade for a narrow cutting path as described above, an extremely thin cutting blade having a thickness of about 10 μm is used.

The polishing sheet disclosed in Patent Document 1 is a polishing sheet that is fixed to the surface of a substrate by an adhesive resin and forms a single layer. The abrasive sheet is characterized in that the abrasive particles are in contact with the front end of the object to be polished on the same plane. Aligned and separated. Therefore, in order to utilize the abrasive sheet as a cutting blade, even if the disc is placed in the cutting device in a disc shape, diamond abrasive grains are formed only on one side. Therefore, the blade is laterally shifted due to uneven left and right. In order to avoid this, if the back surface of the polishing sheet is adhered, the blade becomes thicker, which makes it difficult to perform the microfabrication required in recent years. On the other hand, in the polycrystalline sintered body shown in Patent Document 2, since the average particle diameter of the diamond abrasive grains used is 25 μm or less, it is difficult to form a groove width or cut width of 10 μm or less.

The present invention was made in view of the above-mentioned actual situation, and the purpose is to provide a smooth surface for polishing the object to be polished, and it can also be applied to the grinding of a cutting blade capable of supporting a cutting path (groove width or cutting width) below 10 μm. Flakes and methods of making abrasive flakes. [Means for solving problems]

In order to achieve the above object, the aspect of the polishing sheet of the present invention includes: a flaky substrate; and abrasive grains arranged to penetrate from one surface to the other surface of the substrate.

Preferably, the abrasive grains are arranged on one of the surfaces so as to be in contact with the front end portion of the object to be polished so as to be aligned on the same plane.

Preferably, the aforementioned abrasive particles are arranged separately and form a single particle layer.

Preferably, the average diameter of the abrasive particles is 2 to 3 times the thickness of the substrate.

Preferably, the aforesaid abrasive sheet can be applied to a cutting blade, and the average diameter of the abrasive particles in the wide groove of the cutting groove is 1.1 to 1.5 times.

Preferably, the aforementioned abrasive particles are arranged in a concentric circle shape.

In addition, in order to achieve the above object, the same aspect of the method for manufacturing the abrasive sheet includes: a first step of dispersing abrasive particles on a temporary substrate flat plate; and spreading or The second step of applying the temporary fixing agent; the third step of spreading or coating the raw material constituting the substrate on the temporary substrate flat plate on which the temporary adhesive is spread or coated; The fourth step of peeling the flat surface of the substrate; and the fifth step of dissolving and removing the temporary bonding agent.

In addition, in order to achieve the above object, the same aspect of the method for manufacturing a polishing sheet includes: a first step of punching a plurality of holes in a sheet-like substrate; and a second step of placing abrasive particles having a diameter larger than the diameter of the hole in the hole A step; a third step of pushing the abrasive particles into the holes; and a fourth step of fixing the abrasive particles to the substrate. [Effect of the invention]

According to the present invention, it is possible to provide a polishing sheet and a method for manufacturing a polishing sheet capable of smoothly polishing the surface of an object to be polished, and also applicable to a cutting blade capable of supporting a cutting path (groove width or cutting width) of 10 μm or less .

Hereinafter, the polishing sheet for implementing the aspect of the present invention and a method for manufacturing the polishing sheet will be described with reference to the drawings.

The polishing sheet 10 according to the embodiment of the present invention, as shown in FIG. 1 and FIG. 2, includes: a thin-film-like (sheet-shaped) base material 11; and one side of the base material 11 is penetrated to the other side to be equal The abrasive particles 12 are arranged in a lattice pattern at the separation distance L, and are fixed to the base material 11. The polishing sheet 10 is processed into a disc shape and can be used as the cutting blade 13.

The base material 11 is composed of an organic resin material, or a metal thin film such as nickel or a copper alloy. The organic resin materials include polyolefin resins, polyester resins, acrylic resins, and polycarbonates.

The abrasive grains 12 are separated and arranged approximately evenly, and a single particle layer is formed. The abrasive grains 12 penetrate through the substrate 11 and have distal ends on the left and right. The abrasive grains 12 are arranged on one side and the other side of the base material 11 by protruding the front end portions of the abrasive grains 12. In particular, in the case shown in FIG. 3, the front end portion 21 on the left side is aligned on the polishing surface (the same plane) 22 shown by a broken line. When the polishing sheet 10 is used as an original polishing sheet, the left side surface becomes a polishing surface. The polishing surface 22 is a surface which abuts on a to-be-polished body.

As for the abrasive grain 12, alumina, silica, diamond, silicon carbide, C-BN (Cubic Boron Nitride), etc. are used. Which one is used is selected according to the type of the material to be ground and the grinding accuracy. In addition, when used as the cutting blade 13, in order to exhibit accuracy, diamond-like superabrasive particles are preferred.

If the thickness t of the substrate 11 is assumed, the average diameter d of the abrasive particles 12 is preferably 2t to 3t. When the average diameter d of the abrasive grains 12 is 2 to 3 t, the front end portions of the abrasive grains 12 having a length of approximately t / 2 to t protrude from both sides of the base material 11. If the abrasive sheet 10 is applied to the cutting blade 13, the width of the cutting groove is directly related to the average diameter d of each abrasive particle 12, and is 1.1 to 1.5 times the average diameter d of the abrasive particle 12. In other words, the average diameter d of the abrasive grains 12 corresponds to 70 to 90% of the width of the predetermined cutting groove.

The relationship between the average diameter d of the abrasive grains 12 and the thickness t of the substrate 11 is that if the abrasive sheet 10 is used as the cutting blade 13 and the width of the cut groove is set to 10 μm, the average diameter d of the abrasive grains 12 is 9 μm. The thickness t of the material 11 is 1/2 to 1/3 of the average diameter d = 9 μm, so the thickness t is preferably 4.5 to 3 μm. Although the description is made with the cut groove width of 10 μm as an example, the average diameter d of the abrasive grains 12 and the thickness t of the polishing sheet 10 are changed depending on the cut groove width, and are not limited to those used in this example. Value.

The separation distance L of the abrasive grains 12 which distributes the abrasive grains 12 evenly on the substrate 11 is based on empirical values. It is preferably about 0.5 to 100 times the average diameter d of the abrasive grains 12, and more preferably 2 to 20 times. 3 to 10 times is better. As described above, the strength of the substrate 11 can be maintained, and the abrasive grains 12 per unit area can be increased.

There are various methods for manufacturing the polishing sheet 10 having the above-mentioned characteristics. However, as a representative method for manufacturing the polishing sheet 10, there are a first method for manufacturing the polishing sheet described below, and a second method for manufacturing the polishing sheet. method.

As shown in FIG. 4, the first method for manufacturing abrasive flakes includes a first step of dispersing abrasive particles 12 on a temporary substrate flat plate 31 (step S101); and a temporary substrate surface on which abrasive particles 12 are dispersed. The second step of spreading or coating the temporary fixing agent 32 on the tray 31 (step S102); spreading or coating the raw material constituting the base material 11 on the temporary substrate flat plate 31 on which the temporary fixing agent 32 is spread or coated A third step (step S103); a fourth step of peeling the substrate 11 from the temporary substrate flat plate 31 (step S104); a fifth step of dissolving and removing the temporary adhesive 32 (step S105); and The sixth step of removing the raw material constituting the base material 11 covering the tip of the abrasive grain 12 (step S106).

First, in the first step (step S101), as shown in FIG. 5 (A), the abrasive particles 12 are uniformly dispersed on the temporary substrate flat plate 31. Next, in a second step (step S102), as shown in FIG. 5 (B), a temporary fixing agent 32 having a thickness of at is spread on the temporary substrate flat plate 31 on which the abrasive particles 12 are dispersed. The thickness at is 1/4 of the average diameter d of the abrasive particles 12. Next, in the third step (step S103), as shown in FIG. 5 (C), the temporary base material flat plate 31 on which the temporary fixative agent 32 is spread or coated is placed above the temporary fixative agent 32. The raw material constituting the base material 11 is spread or applied to a thickness t, and the abrasive grains 12 are fixed to the base material 11. The thickness t is 1/2 of the average diameter d of the abrasive particles 12. Next, in the fourth step (step S104), as shown in FIG. 5 (D), after the substrate 11 is cured, the substrate 11 is peeled off from the temporary substrate flat plate 31. Next, in a fifth step (step S105), as shown in FIG. 5 (E), the temporary fixing agent 32 is dissolved and removed. Next, in a sixth step (step S106), the constituent material 33 of the polishing sheet 10 covering the tip of the abrasive grain 12 on the opposite side is dissolved and removed. As described above, the first method for forming a polishing sheet can be used to prepare a desired polishing sheet 10.

The flatness of the temporary substrate flat plate 31 used in the first method of manufacturing the abrasive sheet is extremely important. The flatness of the front end portion of the abrasive grains 12 is the same. The average surface roughness is the average diameter of the abrasive grains 12. d is preferably 5-10%.

As shown in FIG. 6, the second method of manufacturing the abrasive sheet includes: a first step of punching a plurality of holes 41 in the sheet-like substrate 11 (step S201); The second step of the abrasive particles 12 (step S202); the third step of pushing the abrasive particles 12 into the holes 41 (step S203); the fourth step of fixing the abrasive particles 12 to the substrate 11 (step S204); And a fifth step of dissolving and removing the adhesive solution covering the tip of the abrasive grains 12 (step S205).

First, in the first step (step S201), as shown in FIG. 7 (A), the substrate 11 with a thickness t is laser-processed, and the holes with the diameter ad are opened so as to be separated and approximately evenly distributed. 41. The diameter ad of the hole 41 is 1/4 of the average diameter d of the abrasive particles 12. Next, in the second step (step S202), in FIG. 7 (B), the abrasive grains 12 are spread on the base material 11 penetrating the holes 41, and the abrasive grains 12 enter the holes 41 to vibrate, And other abrasive particles 12 are removed. Next, in the third step (step S203), as shown in FIG. 7 (C), the base material 11 that enters the holes 41 into the holes 41 is developed into a clay-shaped flat surface 42 and a plate-shaped flat plate 43 is formed from above Press. At this time, the interval cd between the substrate 11 and the flat plate 43 is about 1/4 to 1/3 of the average diameter d. Thereby, the abrasive grains 12 are pushed into the holes 41 and about 1/4 to 1/3 of the average diameter d of the abrasive grains 12 are exposed from the surface of the substrate 11. In the fourth step (step S204), as shown in FIG. 7 (E), the base material 11 in which the abrasive grains 12 are fitted in the holes 41 is put into the bonding solution 44 so that the base material 11 and The abrasive particles 12 are fixedly connected. Next, in the fifth step (step S205), as shown in FIG. 7 (F), the adhesive solution 44 covering the tip of the abrasive grains 12 is dissolved and removed.

The flatness of the flat plate 43 used in the case of inserting and pressing used in the second method of manufacturing the abrasive sheet is extremely important. The flatness of the front end portion of the abrasive grain 12 is the same, and the average surface roughness is the abrasive grain. The average diameter d of 12 is preferably 5 to 10% or less.

As described above, the polishing sheet 10 is processed into a dish shape and formed into a cutting blade 13 by the polishing sheet 10, and is set in a conventional cutting machine for use, whereby the width of the groove can be arbitrarily cut and cut. In addition, by grinding the front ends of the abrasive grains 12 of the polishing sheet 10 on the same plane toward the object to be polished, the same effect as that of the conventional polishing sheet can be obtained. (Modification)

In the embodiment described above, it is explained that the abrasive particles 12 are arranged in a grid-like polishing sheet 10 with a uniform separation distance L. The abrasive grains 12 may be arranged at a certain separation distance L, may be arranged in a staggered manner as shown in FIG. 8, or may be randomly arranged as shown in FIG. 9.

In addition, in the case where the abrasive sheet 10 is used as the cutting blade 13, each abrasive grain 12 is preferably contacted and cut with the material to be cut at a regular interval. In order to achieve this purpose, the abrasive grains 12 The distribution is preferably as shown below. That is, in the abrasive sheet 10 processed into the cutting blade 13, as shown in FIG. 10, the arrangement of the abrasive grains 12 may be uniformly concentric with respect to the center of the disc-shaped cutting blade 13. Configuration.

The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. In addition, the above-mentioned embodiment is for explaining the present inventors, and is not intended to limit the scope of the present invention. That is, the scope of the present invention is indicated by the scope of patent application rather than the embodiment. Various modifications made within the scope of the patent application and the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

This application is based on Japanese Patent Application No. 2017-088908 filed on April 11, 2017. In this specification, the specification of Japanese Patent Application No. 2017-088908, the scope of patent application, and the entire drawing are incorporated by reference.

10‧‧‧ abrasive flakes

11‧‧‧ Substrate

12‧‧‧ abrasive grain

13‧‧‧ cutting knife

21‧‧‧ front end

22‧‧‧ polished surface

31‧‧‧Temporary substrate flat plate

32‧‧‧Temporary fixing agent

33‧‧‧Constituting materials

41‧‧‧hole

42‧‧‧ Clay plane

43‧‧‧ Tablet

44‧‧‧ Adhesive

ad‧‧‧diameter

cd‧‧‧ interval

d‧‧‧ average diameter

L‧‧‧ separation distance

t, at‧‧‧thickness

[FIG. 1] A plan view showing a polishing sheet according to an embodiment of the present invention. [Fig. 2] An enlarged view of a polishing sheet according to an embodiment of the present invention. [Figure 3] Section III-III of Figure 2. [Fig. 4] Fig. 4 is a flowchart showing a first method of manufacturing a polishing sheet according to an embodiment of the present invention. [FIG. 5] (A) to (F) are diagrams illustrating a step of forming a polishing sheet by the first method of manufacturing a polishing sheet. [FIG. 6] A flowchart showing a second method for manufacturing a polishing sheet according to an embodiment of the present invention. [FIG. 7] (A) to (F) are diagrams illustrating a step of forming a polishing sheet by a second method of manufacturing the polishing sheet. [FIG. 8] A view showing a polishing sheet according to a modification of the present invention. [FIG. 9] A view showing a polishing sheet according to a modification of the present invention. [Fig. 10] Fig. 10 is a view showing a polishing sheet in which abrasive particles are arranged as a cutting blade in a modification of the present invention.

Claims (8)

An abrasive sheet includes: a sheet-like base material; and abrasive particles arranged to penetrate from one side to the other side of the base material. The abrasive sheet according to item 1 of the scope of patent application, wherein the abrasive grains are arranged on one side of the front surface to abut the front end portion of the object to be polished so as to be aligned on the same plane. The abrasive sheet according to item 1 of the scope of the patent application, wherein the abrasive particles are arranged separately and form a single particle layer. The abrasive sheet according to item 1 of the scope of patent application, wherein the average diameter of the abrasive particles is 2 to 3 times the thickness of the substrate. The abrasive flakes described in item 1 of the scope of the patent application, wherein the abrasive flakes can be applied to a cutting blade to cut the wide diameter of the abrasive grains of the grooves by 1.1 to 1.5 times the average diameter. The abrasive sheet according to item 1 of the scope of patent application, wherein the abrasive grains are arranged in a concentric circle shape. A method for manufacturing an abrasive sheet, comprising: a first step of dispersing abrasive particles on a temporary substrate flat disk; and a second step of spreading or coating a temporary fixing agent on the temporary substrate flat disk on which the abrasive particles are dispersed. Process; a third step of spreading or coating the raw material constituting the base material on the temporary base material flat plate on which the temporary bonding agent is dispersed or coated; a fourth step of peeling the base material from the temporary base material flat plate And a fifth step of dissolving and removing the temporary fixing agent. A method for manufacturing an abrasive sheet, comprising: a first step of punching a plurality of holes in a sheet-like substrate; a second step of placing abrasive particles having a diameter larger than the diameter of the holes in the hole; pushing the abrasive particles into The third step to the hole; and the fourth step of fixing the abrasive grains to the substrate.