Life evaluation method

Abstract

To provide a life evaluation method capable of appropriately evaluating the life of a cloth used for polishing a substrate.SOLUTION: The life evaluation method includes a test step of performing a test of repeating a pulling operation of pulling a second portion on the other side of a test fabric piece in a bent state in which a first portion on one side of the test fabric piece is fixed and the test fabric piece is bent at an intermediate position, and an evaluation step of calculating an evaluation value related to the life of the test fabric piece based on a result of the test.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a lifespan evaluation method in which a first portion on one side of a test fabric piece is fixed, and while the fabric piece is bent at a midpoint, a pulling operation is repeatedly performed to pull a second portion on the other side. [Background technology]

[0002] Currently, substrates such as glass substrates for displays are polished to a required flatness. For polishing of such substrates, for example, a substrate polishing method described in Patent Document 1 is used. The method for polishing a substrate in Patent Document 1 includes the steps of attaching a substrate to a film frame having a film body to which the substrate can be attached stretched and attaching the film frame to a carrier, or attaching a film frame having a film body to which the substrate can be attached stretched to a carrier and attaching the substrate to the film frame, bringing the carrier to which the film frame is attached and a polishing table close together and pressing the polished surface of the substrate attached to the film body against the polishing table to polish it, and after polishing of the substrate, removing the film frame from the carrier and removing the substrate from the film frame, or after polishing of the substrate, removing the substrate from the film frame and removing the film frame from the carrier. The film body is made of a three-layer fabric consisting of an airtight layer, a strength-retaining layer, and a smooth layer. The film body of Patent Document 1 presses the polishing surface of the substrate against the polishing platen. To polish substrates over a long period of time, it is necessary to know the lifespan of the film body made of a material, such as its repeated fatigue resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-122351 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, the lifespan of a membrane made of fabric can be evaluated, for example, by measuring the tensile strength of the fabric that makes up the membrane. The tensile strength of the fabric is measured, for example, using JIS L 1096 Method A (strip method). When the tensile strength of the material that constitutes the film is used to evaluate the lifespan of the above-mentioned film, the tensile strength of the material that constitutes the film has little correlation with the lifespan of the film (material) in an actual machine using a substrate polishing device such as a glass substrate, and the current situation is that the lifespan of the film cannot be appropriately evaluated. The present invention has been made with a focus on materials used in polishing substrates, and aims to provide a life evaluation method that can appropriately evaluate the life of materials used in polishing substrates. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the following configuration. (1) A lifespan evaluation method including a test step in which a first portion on one side of a test fabric piece is fixed and the test fabric piece is bent at an intermediate position, and a test is conducted in which a pulling operation is repeatedly performed to pull a second portion on the other side of the test fabric piece, and an evaluation step in which an evaluation value for the lifespan of the test fabric piece is calculated based on the test results. (2) A life evaluation method according to (1), wherein in the test step, the bending angle of the test fabric piece in a bent state is 80° or more and 100° or less. (3) The test process involves fixing a first portion of the test fabric piece with a first jig having a corner with a curvature radius of 2 to 4 mm, and bending the test fabric piece at the corner at a midpoint, A life evaluation method described in (1) or (2), in which a test is conducted in which a second portion of the test fabric piece is fixed to a second jig and a tensile operation is repeatedly performed to pull the second portion of the test fabric piece.

[0006] (4) A life evaluation method described in (3), wherein the surface roughness of the contact surface where the first jig comes into contact with the test fabric piece and the arithmetic mean roughness Ra of the contact surface where the second jig comes into contact with the test fabric piece are each 3.2 to 6.4 μm. (5) A life evaluation method described in (3) or (4), in which the first jig clamps and fixes a first portion of the test fabric piece between two members fixed by a fastening member, and when the test fabric piece is clamped and fixed, the distance between the first portion of the test fabric piece and the fastening member is 0.5 to 1.5 mm. (6) A life evaluation method described in any one of (3) to (5), wherein the second jig clamps and fixes the second portion of the test fabric piece between two members fixed by a fastening member, and when the test fabric piece is clamped and fixed, the distance between the second portion of the test fabric piece and the fastening member is 0.5 to 1.5 mm. (7) The test process involves repeatedly pulling the second portion of the test fabric piece at a predetermined load in a bent state, and obtaining test data for each load on the number of repetitions of the pulling operation when the test fabric piece breaks at the predetermined load. The life evaluation method according to any one of (1) to (6), wherein the evaluation step calculates an evaluation value based on the correspondence between the load and the number of repetitions identified from a plurality of test data acquired for each load. (8) The life evaluation method according to any one of (1) to (7), wherein the test fabric piece is made of aramid fiber. [Effects of the Invention]

[0007] According to the present invention, a life evaluation method can be provided that can appropriately evaluate the life of a material used for polishing a substrate. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing an example of a substrate polishing apparatus. [Figure 2] 2 is a schematic cross-sectional view showing an enlarged view of a film frame of an example of a substrate polishing apparatus. FIG. [Figure 3] 1 is a schematic diagram illustrating an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention. [Figure 4] 2 is a schematic diagram showing a first jig of an example of an evaluation device used in the life evaluation method according to the embodiment of the present invention. FIG. [Figure 5]2 is a schematic diagram showing a first jig of an example of an evaluation device used in the life evaluation method according to the embodiment of the present invention. FIG. [Figure 6] 1 is a schematic side view showing a first jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention. [Figure 7] 3 is a schematic diagram showing a second jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention. FIG. [Figure 8] 1 is a graph showing the load applied to a test piece of fabric in an evaluation device used in a lifespan evaluation method according to an embodiment of the present invention. [Figure 9] 1 is a graph showing an example of test data obtained by the life evaluation method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are merely illustrative for explaining the present invention, and the present invention is not limited to the embodiments shown below. Furthermore, the drawings are simplified for explaining the present invention, and the present invention is not limited to the configurations shown in the drawings below. Note that various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. In the following, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. For example, when ε is a numerical value ε α ~number ε β That is, the range of ε is the number ε α and the number ε β The range includes ε α ≦ε≦ε β is. Unless otherwise specified, the numerical values ​​representing the size of the test fabric piece, such as width, length, and thickness, as well as the radius of curvature, include the error range generally accepted in the relevant technical field. Unless otherwise specified, the specific angles include a tolerance range generally accepted in the relevant technical field. Unless otherwise specified, the loads also include a tolerance range generally accepted in the relevant technical field. The surface roughness also includes a tolerance range generally accepted in the relevant technical field.

[0010] FIG. 1 is a schematic cross-sectional view showing an example of a substrate polishing apparatus, and FIG. 2 is a schematic cross-sectional view showing an enlarged view of a film frame of the example of the substrate polishing apparatus. The substrate polishing apparatus 100 is an apparatus used for polishing glass substrates, etc. In the substrate polishing apparatus 100, for example, an upper frame 102 is provided on a lower surface 101b of a sliding ring 101. A lower frame 104 is attached to a lower surface 102b of the upper frame 102. An end of the membrane 108 is sandwiched between the lower surface 102b of the upper frame 102 and the lower frame 104, and the membrane 108 is stretched by the upper frame 102 and the lower frame 104. Although not shown, the membrane 108 is made of a three-layer fabric, for example, consisting of an airtight layer, a strength layer, and a smooth layer. The membrane 108 is a fabric used for polishing the glass substrate 112. The strength layer needs to have a tension that can withstand the frictional force acting on the glass substrate 112 during polishing, and the strength layer provides the strength of the membrane 108 and is made of a fabric containing aramid fibers or the like. The lifespan of the strength layer has a significant impact on the lifespan of the membrane 108. The airtight layer of the membrane 108 corresponds to the backing described below. The upper frame 102 and the lower frame 104 are fastened together by, for example, bolts (not shown). The sliding ring 101, the upper frame 102, and the lower frame 104 form a membrane frame 110. A carrier 106 is provided in an opening 105 of the sliding ring 101, the upper frame 102, and the lower frame 104. The carrier 106 is movable forward and backward relative to the opening 105. A seal member may be disposed between an inner peripheral surface 101c of the sliding ring 101 and an outer peripheral surface 106c of the carrier 106.

[0011] The carrier 106 has an outer peripheral ring portion 106a that protrudes toward the lower surface 101b of the sliding ring 101. The outer peripheral ring portion 106a of the carrier 106 presses the back surface 108b of the membrane 108, which is stretched between the upper frame 102 and the lower frame 104, to push the membrane 108 downward below the lower surface 104b of the lower frame 104. An air chamber 109 is formed between the inner flat surface portion 106b of the outer peripheral ring portion 106a of the carrier 106 and the membrane body 108. The carrier 106 is provided with a plurality of injection ports 107 that penetrate the sliding ring 101, the upper frame 102, and the lower frame 104 in the stacking direction. Compressed air is supplied from an air pump (not shown) to the nozzle 107, and air is supplied to the air chamber 109. The air supplied to the air chamber 109 applies pressure to the membrane 108.

[0012] For example, an aluminum substrate 111 is disposed on a surface 108a of the film body 108. A glass substrate 112 is disposed on a surface 111a of the aluminum substrate 111. A polishing pad 114 is disposed facing a surface 112a of the glass substrate 112. Compressed air is supplied from an air pump (not shown) to the nozzle 107, and when air is supplied to the air chamber 109, pressure acts on the film 108, causing the film 108 to protrude toward the lower surface 104b of the lower frame 104 and press the glass substrate 112 against the polishing pad 114. In this state, the glass substrate 112 is polished. As described above, the carrier 106 presses the back surface 108b of the membrane 108 with the outer ring portion 106a, pushing the membrane 108 downward below the lower surface 104b of the lower frame 104. At this time, the membrane 108 is bent between the lower frame 104 and the carrier 106, as shown in FIG. 2. The bending angle of the bent portion 108c of the membrane 108 is approximately 90°. It has been found that the bent portion 108c of the membrane 108 has a small radius of curvature and is therefore prone to fracture. The fracture of the membrane 108 occurs at or near the bent portion 108c, and is not caused by simple tension in one direction.

[0013] Based on the above findings, the characteristic features of the lifespan evaluation method of the present invention are that it includes a testing process in which a first portion on one side of a test fabric piece is fixed and the test fabric piece is bent at an intermediate position, and a test is conducted in which a pulling operation is repeatedly performed to pull a second portion on the other side of the test fabric piece, and an evaluation process in which an evaluation value for the lifespan of the test fabric piece is calculated based on the results of the test. The above-described life evaluation method can appropriately evaluate the life of materials used for polishing substrates, and can therefore be used to select materials with excellent cyclic fatigue resistance (long life), for example. Meanwhile, we attempted to evaluate the cyclic fatigue of materials (films) used in polishing glass substrates and the like using a test method conforming to JIS standards, such as the aforementioned JIS L 1096 A method (strip method). However, the evaluation using the test method conforming to JIS standards did not match the evaluation using an actual substrate polishing machine. This is thought to be because, as mentioned above, breakage of film 108 does not occur due to simple unidirectional tension, and the location where film 108 (see Figure 2) is prone to breakage is at or near bent portion 108c (see Figure 2), which has a bending angle of approximately 90°. Note that simple unidirectional tension is reproduced by tensioning the test fabric piece (fabric (membrane)) in an unbent state, that is, by a tension test in the 0° direction. In contrast, by conducting a test in which the above-mentioned test fabric piece was repeatedly pulled in a bent state, it was believed that this simulated the areas where the membrane 108 was prone to breakage, and it was confirmed that this was highly consistent with the evaluation using an actual substrate polishing device and had a high correlation compared to the results of a tensile test in which the tensile direction was 0°. Furthermore, when the film (material) is used in a conventional polishing apparatus for polishing substrates such as glass substrates and the lifespan is evaluated by actual machine evaluation, many film (material) materials are required and measurements must be taken until the film (material) actually breaks, which is costly and takes a long time to evaluate the lifespan. In contrast, the life evaluation method of the present invention uses test substrate pieces instead of the conventional method of evaluating actual substrates such as glass substrates using a polishing device, so that many film bodies (substrates) are not required, costs can be reduced, and the evaluation time can be shortened.

[0014] <Example of evaluation device used in life evaluation method> FIG. 3 is a schematic diagram showing an example of an evaluation device used in the life evaluation method according to the embodiment of the present invention. Fig. 4 is a schematic diagram showing a first jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention, Fig. 5 is a schematic diagram showing a first jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention, Fig. 6 is a schematic side view showing a first jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention, and Fig. 7 is a schematic diagram showing a second jig of an example of an evaluation device used in a life evaluation method according to an embodiment of the present invention. The evaluation device 10 shown in FIG. 3 is used in the method for evaluating the life span of a test piece of fabric. The evaluation device 10 includes a testing section 12 , an evaluation section 13 , a control section 14 , a monitor 15 , and an input section 16 . The testing unit 12 performs a test in which the test fabric piece 26 is repeatedly pulled in a bent state, as described below. That is, the testing unit 12 repeatedly applies a load to the test fabric piece 26 in a bent state, as described below. The testing unit 12 may be a known universal testing machine (universal material testing machine) used for tensile tests of various materials. The evaluation unit 13 calculates an evaluation value for the lifespan of the test piece 26 based on the test results obtained by the testing unit 12.

[0015] The control unit 14 controls the operations of the testing unit 12 and the evaluation unit 13, and controls the display on the monitor 15. The control unit 14 can also control the operations of the testing unit 12 and the evaluation unit 13 and the display on the monitor 15 in response to input from the input unit 16. The control unit 14 may be configured as a computer equipped with an arithmetic processing unit such as a CPU (Central Processing Unit), or may be a dedicated device configured with a dedicated circuit, or may be configured as a server to be executed on the cloud. For example, a program (computer software) stored in a ROM (Read Only Memory) or the like is executed by the arithmetic processing unit to generate control signals to control the operation of the testing unit 12 and the evaluation unit 13, as well as the display on the monitor 15.

[0016] The monitor 15 displays, for example, the input information input by the input unit 16, the test data acquired by the testing unit 12, and the evaluation value calculated by the evaluation unit 13. The monitor 15 also displays, for example, the test conditions and the type and size of the test piece. The monitor 15 is not particularly limited, and various known displays such as a liquid crystal display can be used. The monitor 15 can be a display screen of a mobile communication terminal such as a smartphone or a tablet terminal.

[0017] The input unit 16 is an interface device that receives information from the outside and transmits the information to the control unit 14. The input unit 16 has, for example, an operation unit through which the operator inputs input information, or a communication interface device that enables connection to an external computer. The operation unit is, for example, a touch panel, buttons, a mouse, a lever, a keyboard, etc. Furthermore, the character input function of a mobile communication terminal such as a smartphone or a tablet terminal can be used as the input unit 16.

[0018] The testing section 12 has a first jig 20, a second jig 21, a connecting rod 22, a load cell 23, a driving section 24, and a testing machine bed 25. The first jig 20 is placed on a surface 25a of the testing machine bed 25. The second jig 21 is fastened to a connecting rod 22, and the connecting rod 22 is connected to a load cell 23. The load cell 23 is connected to a drive unit 24. As shown in Fig. 3, the first jig 20 has a base 30 and a fixing portion 32. The base 30 shown in Fig. 4 has, for example, a base 30a that is rectangular in plan view and an arrangement portion 30b that is also rectangular in plan view. The arrangement portion 30b has a shorter short side than the base 30a. The base 30a is fixed to the testing machine bed 25, for example, by bolts (not shown). The arrangement portion 30b is provided with, for example, two rows of female thread portions 33 spaced apart at a predetermined interval. The test fabric piece 26 is placed on the surface 30c of the placement portion 30b between the rows of the female thread portions 33. A plurality of female thread portions 33 are arranged side by side in each row, and the number of female thread portions 33 in each row is the same. For example, a screw (external thread) as a fastening member is screwed into the internal thread portion 33. When the screw (external thread) is screwed, the outer diameter of the screw (external thread) and the root diameter of the internal thread portion 33 are approximately the same. The surface 30c of the arrangement portion 30b between the rows of the female thread portions 33 is the contact surface where the first jig 20 comes into contact with the test fabric piece 26. From the viewpoint of properly holding the test fabric piece 26, the arithmetic mean roughness Ra of this contact surface is preferably 3.2 to 6.4 μm. The surface roughness of the contact surface is the arithmetic mean roughness Ra, and is specified in JIS B 0601:2001.

[0019] As shown in FIG. 5, the fixing portion 32 has a rectangular shape in a plan view, and its shape and size are substantially the same as those of the arrangement portion 30b shown in FIG. The fixing portion 32 is provided with a plurality of through holes 34 that penetrate from the front surface 32a to the back surface 32b (see FIG. 6). For example, a screw (external thread) is passed through the through hole 34 as a fastening member. When a screw (external thread) is passed through, the diameter is designed to be 1 mm larger than the outer diameter of the screw (external thread). The through holes 34 are provided at positions corresponding to the female thread portions 33 of the placement portion 30b when the fixing portion 32 is placed on the placement portion 30b. Like the female thread portions 33, the through holes 34 are provided in two rows at a predetermined interval. For example, the number of through holes 34 in each row is the same as the number of female thread portions 33. Therefore, the fixing portion 32 can be placed on the surface 30c of the placement portion 30b by aligning the positions of the through holes 34 of the fixing portion 32 with the female thread portions 33 of the placement portion 30b. With the fixing portion 32 placed on the surface 30c of the placement portion 30b in this manner, a fastening member, for example, a screw is passed through the through hole 34 and threadedly engaged with the female thread portion 33 to fasten the fixing portion 32 and the placement portion 30b together, thereby fixing the first portion 26a of the test fabric piece 26.

[0020] The fixing portion 32 of the first jig 20 has a corner portion 32d as shown in Fig. 6. Note that in Fig. 6, the through-hole 34 shown in Fig. 5 is not shown. The test fabric piece 26 is bent along the corner 32 d of the fixing portion 32 of the first jig 20 . Corner 32d is a region connecting back surface 32b and side surface 32c, and is formed by a curved surface. Corner 32d has a curvature radius R of, for example, 2 to 4 mm, with a curvature radius R of 3 mm being preferred. The angle formed by the tangent to the back surface 32b of the fixing portion 32 and the tangent to the side surface 32c of the fixing portion 32 is, for example, 90°. During the test, the test fabric piece 26 breaks, for example, at the corner 32d. The back surface 32b of the fixing portion 32 between the rows of through holes 34 is the contact surface where the first jig 20 comes into contact with the test fabric piece 26. The arithmetic mean roughness Ra of this contact surface is preferably 3.2 to 6.4 μm, similar to the surface 30c of the placement portion 30b described above, from the viewpoint of properly holding the test fabric piece 26.

[0021] The first jig 20 sandwiches and fixes the first portion 26a of the test fabric piece 26 between two members secured by fastening members such as screws. When the test fabric piece 26 is sandwiched and fixed in the first jig 20, the distance between the first portion 26a of the test fabric piece 26 and the fastening members such as screws is preferably 0.5 to 1.5 mm to more reliably fix the first portion 26a of the test fabric piece 26. Specifically, as shown in FIG. 4, the distance δ between the first portion 26a of the test fabric piece 26 and the female thread portion 33 of the placement section 30b is preferably 0.5 to 1.5 mm. When a screw (male thread) is threaded into the female thread portion 33 as described above, the outer diameter of the screw (male thread) and the root diameter of the female thread portion 33 are approximately the same. Therefore, the distance δ between the first portion 26a of the test fabric piece 26 and the female thread portion 33 of the placement portion 30b can be considered to be the distance between the first portion 26a of the test fabric piece 26 and a fastening member such as a screw. Furthermore, as shown in Figure 5, the distance δ between the first portion 26a of the test fabric piece 26 and the through hole 34 of the fixing portion 32 is preferably 0.5 to 1.5 mm in order to fix the first portion 26a of the test fabric piece 26 more securely. When a screw (external thread) is passed through the through hole 34 as described above, the outer diameter of the screw (external thread) approximately matches the inner diameter of the through hole 34. Therefore, the distance δ between the first portion 26a of the test fabric piece 26 and the through hole 34 of the fixing part 32 can be considered to be the distance between the first portion 26a of the test fabric piece 26 and a fastening member such as a screw.

[0022] 3, the second jig 21 has a base portion 40 and a fixing portion 42. The base portion 40 has a rectangular shape in a plan view, and has a base 43 with a thick end portion 43d. As shown in FIG. 7, a connecting member 44 for connecting to the connecting rod 22 is provided at an end 43d of the base 43 of the base portion 40. Two rows of female threads 46 are provided at a predetermined interval on the base 43. The test fabric piece 26 is placed on the surface 43a of the base 43 between the rows of female threads 46. A plurality of female threads 46 are provided side by side in each row, and the number of female threads 46 in each row is the same. A screw (external thread), for example, as a fastening member, is threaded into the female thread portion 46. When the screw (external thread) is threaded, the outer diameter of the screw (external thread) and the root diameter of the female thread portion 46 are approximately the same.

[0023] The fixing portion 42 has a rectangular shape in a plan view, and is approximately the same size as the base 43. The fixing portion 42 is provided with a plurality of through holes (not shown) that penetrate from the front surface 42a to the back surface 42b shown in FIG. A screw (external thread), for example, is passed through the through hole as a fastening member. When the screw (external thread) is passed through, the outer diameter of the screw (external thread) and the inner diameter of the through hole are approximately the same. The through holes are provided at positions corresponding to the female thread portions 46 of the base 43 when the fixing portion 42 is placed on the surface 43a of the base 43. Like the female thread portions 46, the through holes are provided in two rows at a predetermined interval. For example, the number of through holes in each row is the same as the number of female thread portions 46. Therefore, the fixing portion 42 can be placed on the surface 43a of the base 43 by aligning the positions of the through holes of the fixing portion 42 with the female thread portions 46 of the base 43. With the fixing portion 42 placed on the surface 43a of the base 43 in this manner, fastening members such as screws are passed through the through holes and screwed into the female thread portions 46 to fasten the fixing portion 42 and the base 43 together with the screws, thereby fixing the second portion 26b of the test fabric piece 26.

[0024] The surface 43a of the base 43 between the rows of the female thread portions 46 is the contact surface where the second jig 21 comes into contact with the test fabric piece 26. From the viewpoint of properly holding the test fabric piece 26, the arithmetic mean roughness Ra of this contact surface is preferably 3.2 to 6.4 μm. Furthermore, the surface of the fixing portion 42 between the rows of through holes is the contact surface where the second jig 21 comes into contact with the test fabric piece 26. From the viewpoint of properly holding the test fabric piece 26, the arithmetic mean roughness Ra of this contact surface is preferably 3.2 to 6.4 μm.

[0025] The second jig 21 clamps and fixes the second portion 26b of the test fabric piece 26 between two members secured by a fastening member such as a screw. When the test fabric piece 26 is clamped and fixed in the second jig 21, the distance between the second portion 26b of the test fabric piece 26 and the fastening member such as a screw is preferably 0.5 to 1.5 mm to more reliably fix the second portion 26b of the test fabric piece 26. Specifically, as shown in FIG. 7, the distance δ between the second portion 26b of the test fabric piece 26 and the female thread portion 46 of the base 43 is preferably 0.5 to 1.5 mm. When a screw (male thread) is threaded into the female thread portion 46 as described above, the outer diameter of the screw (male thread) and the root diameter of the female thread portion 46 are approximately the same. Therefore, the distance δ between the second portion 26b of the test fabric piece 26 and the female thread portion 46 of the base 43 can be considered to be the distance between the second portion 26b of the test fabric piece 26 and a fastening member such as a screw. Furthermore, although not shown, the distance δ between the second portion 26b of the test fabric piece 26 and the through hole (not shown) of the fixing portion 42 is preferably 0.5 to 1.5 mm in order to more securely fix the second portion 26b of the test fabric piece 26. When a screw (external thread) is passed through the through-hole as described above, the outer diameter of the screw (external thread) and the inner diameter of the through-hole are approximately the same. Therefore, the distance δ between the second portion 26b of the test fabric piece 26 and the through-hole of the fixing part 42 can be considered to be the distance between the second portion 26b of the test fabric piece 26 and a fastening member such as a screw. The first jig 20 and the second jig 21 are made of, for example, SS400 (general structural rolled steel), but are not limited to this. Although screws are used as an example of fastening members, the fastening members are not limited to screws and may be bolts.

[0026] The test fabric piece 26 has a first portion 26a fixed by the first jig 20 and a second portion 26b fixed by the second jig 21. The test fabric piece 26 is bent along the corner 32d (see FIG. 6) of the fixing portion 32 of the first jig 20, and is bent at a midpoint of the test fabric piece 26. The angle between the tangent to the back surface 32b of the fixing part 32 and the tangent to the side surface 32c of the fixing part 32 is, for example, 90°, so the bending angle of the test fabric piece in the bent state is 90°. When the bending angle is 90°, the tensile direction during the test is 90°. The bending angle of the test piece in the bent state is not limited to 90°, but is preferably 80° to 100°. If the bending angle is 80° to 100°, the test piece can be used to appropriately evaluate the lifespan of the material used for polishing substrates. The bending angle is the angle between the tangent to the back surface 32b of the fixed portion 32 and the tangent to the side surface 32c of the fixed portion 32, so the bending angle can be changed, for example, by changing the angle of the side surface 32c of the fixed portion 32 relative to the back surface 32b.

[0027] The drive unit 24 is not particularly limited as long as it can apply a predetermined load to the test fabric piece 26 at a predetermined speed, and any drive unit used in known tensile testing devices can be used as appropriate. The drive unit 24 is also connected to a load cell 23, which is a load sensor that measures the load, and load information is obtained from the load cell 23. The configuration of the load cell 23 is not particularly limited as long as it can measure the load, and any known load cell can be used as appropriate. Furthermore, for example, the driving unit 24 can be an actuator that drives linearly. The drive unit 24 can move the second jig 21 in the vertical direction perpendicular to the surface 25a of the testing machine bed 25 via the connecting rod 22. This allows a test to be performed on the test fabric piece 26 by repeatedly pulling the fabric piece 26. At this time, the load is measured by the load cell 23. Furthermore, the drive unit 24 repeatedly pulls the second portion 26b of the test fabric piece 26 with a predetermined load via the connecting rod 22 and the second jig 21. In this case, for example, a cyclic load is applied to the test fabric piece 26. An example of the cyclic load is an amplitude load such as the load waveform 50 shown in FIG. 8. From the viewpoint of reducing the number of repetitions, it is preferable that the cyclic load has a large load ratio between the maximum load Fmax and the minimum load Fmin. For example, when the maximum load Fmax is 100, it is preferable that the minimum load Fmin is 10. In this case, the minimum load Fmin is 1 / 10 of the maximum load Fmax. A large load ratio is preferable because it reduces the number of repetitions and shortens the time required for the test. The above-mentioned repeated loads, including the maximum load and the minimum load, are loads per width of the test fabric piece 26, and are expressed in units of N / mm.

[0028] The testing unit 12 repeatedly performs a pulling operation to pull the second portion 26b of the test fabric piece 26 with a predetermined load while the test fabric piece 26 is bent, and obtains test data for each of a plurality of loads indicating the number of repetitions of the pulling operation at which the test fabric piece 26 breaks at the predetermined load. The test data indicating the number of repetitions at which the test fabric piece 26 breaks at the predetermined load is obtained by the evaluation unit 13. The evaluation unit 13 calculates an evaluation value for the lifespan of the test fabric piece 26 based on the results of a test in which the second portion 26b of the test fabric piece 26 is repeatedly pulled. More specifically, the evaluation unit 13 calculates the evaluation value based on the correspondence between the load and the number of repetitions identified from multiple test data obtained for each load. For example, as shown in Figure 9, a test is conducted on a certain test fabric piece 26, resulting in a plurality of test data 52a, 52b, 52c, and 52d. Note that in Figure 9, the load on the vertical axis is normalized. The horizontal axis shows the number of times in logarithm, and the number on the horizontal axis is the number of repetitions. The evaluation unit 13 performs linear approximation using, for example, the least squares method on the plurality of test data 52a, 52b, 52c, and 52d to obtain an approximated straight line 54 that indicates the relationship between the load and the number of repetitions on the test fabric piece 26. In this case, the approximated straight line 54 is expressed as a linear function. For example, approximate straight lines 55a, 55b, and 55c are obtained for each test piece of fabric. In the evaluation device 10, the control unit 14 can display on the monitor 15 approximate straight lines 54, 55a, 55b, and 55c as shown in FIG.

[0029] The evaluation unit 13 uses an approximate straight line for each test piece to calculate, for example, the load at a repetition count (hereinafter simply referred to as the count) of 30,000 as an evaluation value. In the case of the approximate straight line 54 shown in Figure 9, the evaluation value is the load at point P1 at a repetition count of 30,000. Approximate line 55a represents the load at point P2 when the number of times is 30,000. Approximate line 55b represents the load at point P3 when the number of times is 30,000. Approximate line 55c represents the load at point P4 when the number of times is 30,000. The lifespan of the test piece, i.e., the lifespan of the fabric constituting the test piece, is evaluated using the above-mentioned evaluation value. Specifically, for example, the load at 30,000 times is calculated, and the larger the load at 30,000 times, the longer the lifespan is evaluated. For example, approximate lines 55b and 55c in Fig. 9 have different slopes, and when the number of cycles is small, approximate line 55c has a larger load than approximate line 55b, but as the number of cycles increases, the degree of load reduction for approximate line 55c becomes greater, and the load at 30,000 cycles is larger for approximate line 55b (see point P4) than for approximate line 55c (see point P3). The test fabric piece represented by approximate line 55b has a longer lifespan than the test fabric piece represented by approximate line 55c. The approximate line of the test fabric piece is preferably large in load and small in slope when the number of times is small, because it is evaluated as having a long lifespan. In other words, when the approximate line of the test fabric piece is expressed as a linear function, it is preferable that the intercept is large and the slope is small, considering the lifespan. For example, when the load at 30,000 times was compared with an evaluation using an actual device for polishing a substrate such as a glass substrate, it was confirmed that the life evaluation using the load at 30,000 times was consistent with the evaluation using an actual device for polishing a substrate. For this reason, the life evaluation method can be used, for example, to select fabrics with excellent resistance to repeated fatigue (long life).

[0030] <Example of lifespan evaluation method> The life evaluation method uses, for example, an evaluation device 10 shown in Fig. 3. The life evaluation method is not limited to using the evaluation device 10 shown in Fig. 3. The lifespan evaluation method includes a testing step in which a first portion 26a on one side of the test fabric piece 26 is fixed with a first jig 20, and the test fabric piece 26 is bent at an intermediate position to perform a test in which a pulling operation is repeated to pull a second portion 26b on the other side of the test fabric piece 26, and an evaluation step in which an evaluation value regarding the lifespan of the test fabric piece 26 is calculated by the evaluation unit 13 based on the test results. The lifespan evaluation method will be described in more detail below.

[0031] First, for example, as shown in FIG. 3, the base 30a of the base 30 of the first jig 20 is fixed to the surface 25a of the testing machine bed 25, and the base 40 of the second jig 21 is connected to the connecting rod 22. The first portion 26a on one side of the test fabric piece 26 is placed between the rows of female thread portions 33 of the placement portion 30b of the base 30 of the first jig 20 shown in Figure 4. In this state, the fixing portion 32 is then placed on the surface 30c of the placement portion 30b, and a fastening member, for example a screw, is passed through the through hole 34 and screwed into the female thread portion 33 to fasten the placement portion 30b and the fixing portion 32. This fixes the first portion 26a on one side of the test fabric piece 26 to the first jig 20. Next, the test fabric piece 26 is bent along the corner 32d of the fixing portion 32 (see FIG. 6). In this state, the second portion 26b on the other side of the test fabric piece 26 is placed between the rows of female thread portions 46 of the base 43 shown in FIG. 7. The fixing portion 42 is placed on the surface 43a of the base 43, and with the fixing portion 42 placed on the surface 43a of the base 43, a fastening member, for example, a screw is passed through the through hole and screwed into the female thread portion 46 to fasten the base 43 and the fixing portion 42. This fixes the second portion 26b on the other side of the test fabric piece 26 to the second jig 21. With the test fabric piece 26 bent at a 90° angle, the first portion 26a is fixed to the first jig 20, and the second portion 26b is fixed to the second jig 21.

[0032] Next, based on the set test conditions such as the pulling speed, load, and load ratio, a test is carried out in which the test fabric piece 26 is in a bent state and the second portion 26b on the other side of the test fabric piece 26 is repeatedly pulled until the test fabric piece 26 breaks. This provides test data on the number of repetitions at which the test fabric piece 26 breaks under a specified load. In the testing process, the load is changed for the test fabric piece 26 made of the same material, and the above-mentioned test data is obtained for each of the multiple loads. The obtained test data can be shown in a graph, for example, as shown in FIG. In order to obtain test data for each of a plurality of loads, a plurality of test fabric pieces are prepared for the fabric to be evaluated for lifespan.

[0033] Next, in the evaluation step, an evaluation value is calculated based on the correspondence between the load and the number of repetitions identified from the multiple test data acquired for each load. In this case, as described above, the multiple test data are linearly approximated using, for example, the least squares method to obtain an approximated line 54 (see FIG. 9) that shows the relationship between the load and the number of repetitions of the test fabric piece 26. The approximated line 54 is expressed, for example, by a linear function. Using the approximation line, for example, the load at 30,000 times is calculated as an evaluation value. This evaluation value is used to evaluate the lifespan of the test fabric piece, i.e., the lifespan of the fabric that makes up the test fabric piece. Specifically, the larger the load at 30,000 times, the longer the lifespan is evaluated.

[0034] <Test piece> The test piece is made of a material to be evaluated for lifespan, which is a material used for polishing substrates. For the membrane of a polishing apparatus for substrates such as glass substrates, fabrics containing aramid fiber, carbon fiber, glass fiber, nylon fiber, etc. are used. Among these, aramid fiber has extremely little elongation under tensile force, so it is preferable that the test piece be made of aramid fiber, which is a material used for polishing substrates. In other words, it is preferable that the test piece be made of aramid fiber. The test fabric piece may also have a lining. The lining may be made of, for example, rubber, silicone, fluororesin, vinyl such as polyvinyl chloride (PVC), nylon, urethane resin, etc. Among these, vinyl chloride and urethane resin are preferred for the lining in terms of manufacturing, with urethane resin being particularly preferred. When the membrane 108 (see FIG. 1) is made of a three-layer fabric consisting of an airtight layer, a strength layer, and a smooth layer, for example, the backing corresponds to the airtight layer. [Example]

[0035] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. Of the following Examples 1 to 5, Examples 1 to 3 are working examples, and Examples 4 and 5 are comparative examples. For each of Examples 1 to 5, a life evaluation and an actual machine evaluation using a substrate polishing apparatus were carried out.

[0036] [Lifespan evaluation method] (Example 1) Tensile tests were carried out using a tensile testing machine (Instron Precision Universal Testing Machine 68-TM50). In Examples 1 to 3, the first and second jigs described above were used for the tensile tests. In Examples 4 and 5, the jigs of the tensile testing machine were used. The first and second jigs were made of SS400. The arithmetic mean roughness Ra of the contact surface of the test piece in the first and second jigs was set to 6.4 μm. In addition, the distance δ between the female thread and the test piece in the first and second jigs (see Figures 4, 5, and 7) was set to 1 mm. The arithmetic mean roughness Ra of the contact surface was measured using a surface roughness meter. The test conditions were a tensile speed of 50 mm / min, a load ratio of 0.1, and a maximum number of repetitions of 20,000. The load was applied in the longitudinal direction of the test fabric piece. A load ratio of 0.1 means that when the maximum load Fmax is 100, the minimum load Fmin is 10. The first and second jigs were used, and the bending angle of the test fabric piece in the bent state was 90°. When the bending angle was 90°, the tensile direction was 90°.

[0037] In Example 1, the test fabric was made of DuPont's Kevlar (registered trademark) with a fiber density of 1000d (denier), with urethane resin attached as the backing. The test fabric piece measured 10mm wide x 200mm long and had a thickness of approximately 1.0mm. In Example 1, multiple test fabric pieces made of the same material were prepared. Note that 1000d (denier) is 1111 dtex (decitex). A predetermined load was applied repeatedly until the test fabric piece broke, and the number of repetitions was obtained, thereby obtaining test data on the number of repetitions. For test fabric pieces made of the same material, the load was changed and the above test data was obtained for each of the multiple loads. The test data obtained for each load were linearly approximated using the least squares method to obtain an approximate line showing the relationship between the load on the test fabric piece and the number of repetitions. The approximate line is expressed as a linear function. Using this approximate line, the load at 30,000 repetitions was calculated as the evaluation value. Furthermore, the tensile strength was measured in a bent state (tensile direction 90°) in Example 1. The results are shown in the column "Load equivalent to one cycle."

[0038] (Example 2) Example 2 is the same as Example 1 except that, instead of the Kevlar (registered trademark) fabric used in Example 1, a Technora (registered trademark) fabric with a fiber density of 1500d (denier) was used, and the load at 30,000 repetitions was calculated as the evaluation value. Further, the tensile strength was measured in a bent state (tensile direction 90°) in Example 2. The results are shown in the column "Load equivalent to one cycle." Note that 1500d (denier) is 1667dtex (decitex). (Example 3) Example 3 is the same as Example 1 except that, instead of the Kevlar (registered trademark) fabric of Example 1, a Kevlar (registered trademark) K119N fabric with a fiber density of 1500d (denier) was used, and there was no urethane resin lining. The load at 30,000 repetitions was calculated as the evaluation value. Further, the tensile strength was measured in a bent state (tensile direction 90°) in Example 3. The results are shown in the column "Load equivalent to one cycle."

[0039] (Example 4) Example 4 used the test fabric piece of Example 1. In Example 4, the tensile test was carried out without using the first jig and the second jig and without bending the fabric, unlike Example 1. In Example 4, the bending angle was 0° and the tensile direction was 0°. Furthermore, in Example 4, the load at 30,000 repetitions was not calculated as an evaluation value. The results of the tensile test of Example 4 (tensile direction: 0°) are shown in the column "Load equivalent to one time" in Table 1 below. (Example 5) Example 5 used the test fabric piece of Example 2. In Example 5, the tensile test was carried out without using the first jig and the second jig and without bending the fabric, unlike Example 2. In Example 5, the bending angle was 0° and the tensile direction was 0°. Furthermore, in Example 5, the load at 30,000 repetitions is not calculated as an evaluation value. The results of the tensile test (tensile direction 0°) in Example 5 are shown in the column "Load equivalent to one time" in Table 1 below.

[0040] In Examples 1 to 5, the consistency with the actual evaluation was evaluated by comparing the evaluation values ​​(load repeated 30,000 times) obtained by the life evaluation method for Examples 1 to 3. In addition, in Examples 4 and 5, the consistency with the actual evaluation was evaluated by comparing the results of the actual evaluation with the results of the tensile test (tensile direction 0°). Those with high consistency with the evaluation on the actual machine were marked with "◯", and those with low consistency with the evaluation on the actual machine were marked with "×". In the actual machine evaluation, the fabric used for the test fabric piece was used as a film for polishing substrates, and the number of substrates that could be polished before the fabric broke was counted. In the actual machine evaluation, the more substrates that could be polished, the longer the life of the fabric. In the examples, when the load at 30,000 repetitions was large and the number of substrates that could be polished with the actual machine was large, it was determined that the results were consistent with the evaluation of the actual machine.Furthermore, when the load at 30,000 repetitions was small and the number of substrates that could be polished with the actual machine was small, it was determined that the results were consistent with the evaluation of the actual machine. On the other hand, in the examples, when the load at 30,000 repetitions was large and the number of substrates that could be polished with the actual machine was small, it was determined that the consistency with the actual machine evaluation was low.Furthermore, when the load at 30,000 repetitions was small and the number of substrates that could be polished with the actual machine was large, it was determined that the consistency with the actual machine evaluation was low. In the comparative examples, when the load (load equivalent to one time) in the tensile test (tensile direction 0°) was large and the number of substrates that could be polished with the actual machine was large, it was determined that the results were consistent with the actual machine evaluation.Furthermore, when the load (load equivalent to one time) in the tensile test (tensile direction 0°) was small and the number of substrates that could be polished with the actual machine was small, it was determined that the results were consistent with the actual machine evaluation. On the other hand, in the comparative examples, when the load (load equivalent to one time) in the tensile test (tensile direction 0°) was large and the number of substrates that could be polished with the actual machine was small, it was determined that the consistency with the actual machine evaluation was low. Also, when the load (load equivalent to one time) in the tensile test (tensile direction 0°) was small and the number of substrates that could be polished with the actual machine was large, it was determined that the consistency with the actual machine evaluation was low.

[0041] [Table 1]

[0042] As shown in Table 1, Examples 1 to 3 have higher consistency with the evaluation using an actual machine than Examples 4 and 5. In this way, the life evaluation method of the present invention has higher consistency with the evaluation using an actual machine than the conventional normal tensile test (tensile test with a tensile direction of 0°), and has a higher correlation with the evaluation using an actual machine than the results of the tensile test with a tensile direction of 0°, so the life evaluation was appropriate. [Explanation of symbols]

[0043] 10 Evaluation equipment 12 Testing Department 13 Evaluation Section 14 Control Unit 15 monitors 16 Input section 20 First jig 21 Second jig 22 Connecting rod 23 Load Cell 24 Drive unit 25 Testing Machine Bed 25a surface 26 test pieces 26a Part 1 26b Part 2 30 base 30a base 30b Placement section 30c, 32a, 43a surface 32, 42 Fixed part 32b back side 32c side 32d corner 33 Female thread 34 Through hole 40 base 43 Base 43d end 44 Connecting member 46 Female thread 50 Load waveform 52a, 52b, 52c Test Data 54, 55a, 55b, 55c Approximate straight line 100 Substrate polishing equipment 101 Sliding ring 101b, 102b, 104b bottom side 101c Inner surface 102 Upper frame 104 Bottom frame 105 Opening 106 Career 106a Outer ring part 106b Plane part 106c Outer surface 107 Nozzle 108 Membrane body 108a, 111a, 112a surface 108b back side 108c Bend section 109 Air Chamber 110 Film Frame 111 Aluminum substrate 112 Glass substrate 114 Polishing Pad P1, P2, P3, P4 points R radius of curvature

Claims

1. A test step in which a first portion on one side of the test fabric piece is fixed, and the test fabric piece is bent at an intermediate position, and a second portion on the other side of the test fabric piece is pulled in the bent state; A lifespan evaluation method comprising an evaluation step of calculating an evaluation value for the lifespan of the test fabric piece based on the results of the test.

2. The life evaluation method according to claim 1, wherein in the testing step, the bending angle of the test fabric piece in the bent state is 80° or more and 100° or less.

3. The testing step includes fixing the first portion of the test fabric piece with a first jig having a corner with a curvature radius of 2 to 4 mm, and bending the test fabric piece at the corner at the intermediate position to form the bent state. The life evaluation method according to claim 1 or 2, wherein the second portion of the test fabric piece is fixed to a second jig and a test is conducted in which the pulling action of pulling the second portion of the test fabric piece is repeated.

4. The arithmetic mean roughness Ra of the contact surface where the first jig contacts the test fabric piece and the arithmetic mean roughness Ra of the contact surface where the second jig contacts the test fabric piece are each 3.2 to 6.4 μm. A life evaluation method according to claim 3.

5. The first jig clamps and fixes the first portion of the test fabric piece between two members fixed by a fastening member, The life evaluation method described in claim 3, wherein when the test fabric piece is clamped and fixed, the distance between the first part of the test fabric piece and the fastening member is 0.5 to 1.5 mm.

6. The second jig clamps and fixes the second portion of the test fabric piece between two members fixed by a fastening member, The life evaluation method described in claim 3, wherein when the test fabric piece is clamped and fixed, the distance between the second portion of the test fabric piece and the fastening member is 0.5 to 1.5 mm.

7. The test step includes repeatedly performing the pulling operation of pulling the second portion of the test fabric piece at a predetermined load in the bent state, and obtaining test data for each of a plurality of loads on the number of repetitions of the pulling operation when the test fabric piece breaks at the predetermined load.

3. The life evaluation method according to claim 1, wherein the evaluation step calculates the evaluation value based on a correspondence relationship between the load and the number of repetitions identified from a plurality of test data acquired for each load.

8. The life evaluation method according to claim 1 or 2, wherein the test fabric piece is made of aramid fiber.

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