JP2006009110A - Method for removing dlc film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing a DLC (Diamond Like Carbon) film where a DLC film is partially removed by a plasma etching process in which cost does not increase for masking and treatment time is not largely taken. <P>SOLUTION: Into a work 10 having almost columnar shape, a cylindrical masking member 30 longer than the work 10 and having an inside diameter larger than its diameter is inserted in such a manner that the work 10 is completely covered, and it is placed on a cathode 3 in a chamber. The masking member 30 with which the mask clearance 50 between the outside face of the work 10 and the inner face of the masking member 30 reaches ≤1 mm is used. The side faces of the masking member 30 are provided with a plurality of opening parts 31 having almost rhombic shape, and the parts released at the opening parts 31 are etched. The etching is performed in such a manner that a gaseous mixture of Ar, Cr<SB>4</SB>and O<SB>2</SB>in which the mixing ratio of Ar is ≥70% is introduced into the chamber under a gaseous pressure of ≤26 Pa, and the side face temperature of the work is held at 50 to 250°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a DLC (Diamond Like Carbon) film removing method, and more particularly, to a DLC film removing method for partially removing a DLC film by a plasma etching method.

  Conventionally, various devices such as sewing machines are often slidably assembled with a plurality of sliding parts such as cams, shafts, cranks, etc., and these sliding parts are baked. In order to prevent wear and reduce wear, it is common to supply a lubricant to the sliding portion or to form a coating with excellent wear resistance on the surface of the sliding portion.

  For example, in Patent Document 1, a diamond like carbon (hereinafter referred to as DLC) film having a low friction coefficient and a high hardness is formed as a wear-resistant film on a sliding portion of a needle bar of a sewing machine. However, when a lubricating oil is used as the lubricant, the DLC film has a property of repelling the lubricating oil, so that the lubricating oil supplied to the sliding portion flows out immediately. Therefore, in the sliding component of Patent Document 1, an oil groove is formed in the DLC film, and the lubricating oil is accumulated in the oil groove to prevent the lubricating oil from flowing out as much as possible and maintain the lubricating performance of the sliding portion. A sliding component is disclosed. In this sliding part, the lubricating oil filled in the oil reservoir becomes easy to flow in the same direction as the sliding direction by the sliding of the other sliding component, and the lubricating oil passes through the side wall surface of the oil reservoir and the DLC coating. Supplied to the outer peripheral surface, the lubrication performance of the sliding part is maintained in a high state. In Patent Document 1, a DLC film is formed by attaching a mask in a substantially close contact state, and an oil groove is formed in the masked portion.

First, a DLC film is formed on the entire sliding part, and masking is applied to the part other than the part where the oil groove is formed, and etching is performed to remove the DLC film to form the oil groove, or the DLC film is formed by a focused ion beam or laser. There is also a method of removing oil to form an oil groove. Among these methods, one method for forming the oil reservoir is a kind of dry etching method, and a plasma etching method in which etching is performed using plasma is conceivable. When performing etching by performing masking by this plasma etching method, in order to prevent so-called side etching, etching proceeds to the masked portion, and masking is performed in close contact with the medium to be etched.
Japanese Patent Laid-Open No. 2003-247691

  However, there is a problem in that the contact mask cannot be reused and the cost is increased, and a great deal of time is spent for forming the mask layer.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a DLC film removal method for partially removing a DLC film by a plasma etching method.

  In order to solve the above problems, in the DLC film removal method of the invention according to claim 1, in the DLC film removal method in which the DLC film formed on the surface of the substrate is partially removed by the plasma etching method, the pressure of the etching gas Is 26 Pa or less.

In the DLC film removal method of the invention according to claim 2, in addition to the configuration of the invention of claim 1, the etching gas is a mixed gas of Ar, CF ₄ , O ₂ , and the mixing ratio of Ar is It is the structure characterized by being 70% or more.

  In addition, in the DLC film removal method of the invention according to claim 3, in addition to the configuration of the invention of claim 1 or 2, the temperature of the DLC film when removing the DLC film forms the DLC film. The temperature is equal to or lower than the temperature at which the DLC film is formed in the room.

  In the DLC film removal method of the invention according to claim 4, in addition to the configuration of the invention according to any one of claims 1 to 3, the temperature of the DLC film when removing the DLC film is 50 ° C. or more, 250 It is the structure characterized by being below ℃.

  Further, in the DLC film removal method of the invention according to claim 5, in addition to the configuration of the invention according to any one of claims 1 to 4, there is a gap between the mask that covers the portion where the DLC film is not removed and the DLC film. It is the structure characterized by being 1 mm or less.

  In the DLC film removal method of the invention according to claim 1, in the DLC film removal method in which the DLC film formed on the surface of the substrate is partially removed by the plasma etching method, the pressure of the etching gas is 26 Pa or less. The portion to be etched can be appropriately etched without causing the side etching to be etched up to the masked portion.

Further, in the DLC film removing method of the invention according to claim 2, in addition to the effect of the invention of claim 1, the etching gas which is a mixed gas of Ar, CF ₄ and O ₂ is mixed with Ar 70% or more. Therefore, stable plasma can be generated.

  Moreover, in the DLC film removal method of the invention according to claim 3, in addition to the effect of the invention of claim 1 or 2, the temperature of the DLC film is lower than the temperature in the film forming chamber when the DLC film is formed. Since the DLC film is removed as the temperature, the etching can be performed in a practical time required for etching while maintaining the hardness of the DLC film.

  In the DLC film removal method of the invention according to claim 4, in addition to the effect of the invention according to any one of claims 1 to 3, the temperature of the DLC film when removing the DLC film is 50 ° C. or more and 250 Since the etching is performed at a temperature lower than or equal to ° C., the etching can be performed in a practical time required for performing the etching while maintaining the hardness of the DLC film formed at 250 ° C.

Further, in the DLC film removal method of the invention according to claim 5, in addition to the effect of the invention according to any one of claims 1 to 4, the distance between the mask that covers the portion where the DLC film is not removed and the DLC film is set. Since the thickness is 1 mm or less, a portion to be etched can be appropriately etched without causing side etching to proceed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In various devices such as a sewing machine, a plurality of sliding parts are often slidably assembled. In these sliding parts, seizure of the sliding parts is prevented and wear is reduced. Therefore, a DLC film having a low friction coefficient and a high hardness is formed, and grease is applied as a lubricant to the sliding portion. However, since this DLC film has a property of repelling grease, the grease supplied to the sliding portion flows out immediately. Therefore, in the embodiment of the present invention, an oil groove is formed in the DLC film, and the grease is stored in the oil groove to prevent the grease from flowing out as much as possible and maintain the lubrication performance of the sliding portion. For this purpose, the DLC film is removed by plasma etching to form an oil groove for storing grease.

In the present embodiment, the inventor's own parallel plate type high-frequency plasma etching apparatus is used. FIG. 1 is a schematic view of a chamber 1 of the self-made plasma etching apparatus. As shown in FIG. 1, a plasma processing space 6 is formed in the chamber 1 between the anode 2 and the cathode 3. The anode 2 also functions as a gas shower head that supplies an etching gas. Further, the cathode 3 is an A4 size substrate in the present embodiment, and a workpiece 10 to be subjected to plasma etching is set and placed in a masking member 30 (see FIG. 2) on the substrate. An RF power source 5 is connected to the cathode 3 via a matching box 4. Plasma is generated in the plasma processing space 6 by introducing an etching gas from the gas shower head into the chamber 1 and applying a high-frequency electric field from the RF power source 5. In this embodiment mode, a mixed gas of Ar (argon), CF ₄ (carbon tetrafluoride), and O ₂ (oxygen) is used as an etching gas, and a high frequency electric field of 13.56 MHz and 600 W is applied. CF ₄ and O ₂ are reactive gases for reacting with the DLC film, and Ar is a physical gas for stabilizing the plasma.

  FIG. 2 is an enlarged view of the surface measurement of the workpiece 10 and the masking member 30. The workpiece 10 shown in FIG. 2 is a substantially cylindrical shaft, and the masking member 30 is a cylinder having a length equal to or greater than the length of the workpiece 10 and an inner diameter larger than the diameter of the workpiece 10. . Then, the workpiece 10 is inserted into the masking member 30 so that the masking member 30 completely covers the workpiece 10. The thickness of the masking member 30 is 0.75 mm, and a plurality of substantially diamond-shaped openings 31 are opened on the side surfaces, and the portions opened by the openings 31 are etched. The distance between the outer surface of the workpiece 10 and the inner surface of the masking member 30 is referred to as a mask clearance 50.

  FIG. 3 is an enlarged perspective view of the workpiece 10 covered with the masking member 30 and subjected to plasma etching. FIG. 4 shows the workpiece 10 and the masking member 30 in a state where the DLC film is removed by etching. It is sectional drawing of the AA 'line arrow direction in FIG. As shown in FIG. 3, the DLC film 13 is removed in a substantially rhombus shape having the same shape as the opening 31 of the masking member 30 to form a grease holding portion 40. As shown in FIG. 4, the workpiece 10 is provided with an inclined layer 12 whose composition continuously changes from the hardened steel 11 toward the DLC coating 13 on the surface of the hardened steel 11, which is obtained by quenching the iron surface. The DLC film 13 is formed on the surface. And the masking member 30 is arrange | positioned in the state which is not closely_contact | adhered to the DLC film 13. FIG. Then, the portion of the DLC film 13 exposed to the plasma processing space 6 of the chamber 1 is removed from the opening 31 of the masking member 30 by plasma etching, and the grease holding portion 40 is formed. 3 and 4, the opening 31 has a substantially rhombus shape, but may have other shapes.

  However, the area of the bottom surface 41 of the grease retaining portion 40, that is, the outer surface of the inclined layer 12 exposed by the removal of the DLC film, is larger than the area of the opening 31 due to the environment when performing plasma etching. (So-called side etching). Also, the etching rate (depth at which the DLC film can be removed in one minute) varies depending on the environment during plasma etching, and when this etching rate is low, the time required to remove the DLC film to a desired depth Will become longer.

  Therefore, referring to the experimental results shown in Tables 1 to 4 and FIGS. 5 to 10, the gas pressure of the etching gas and the mixing ratio of Ar to the etching gas have an influence on the environment when performing the plasma etching. The desired values were found for the temperature of the workpiece 10 and the distance of the mask clearance 50.

  First, with reference to Table 1, FIG. 5 and FIG. 6, the experimental results on the gas pressure of the etching gas will be described. Table 1 is a table showing gas pressure, side etching rate and etching rate, FIG. 5 is a graph showing the relationship between gas pressure and side etching rate, and FIG. It is a graph which shows the relationship.

  In this experiment, plasma etching is performed by introducing an etching gas having an Ar mixing ratio of 70% at various gas pressures. The workpiece 10 was coated with a DLC film having a film thickness of 2000 nm, covered with a masking member 30 with a mask clearance of 0.025 mm, and subjected to plasma etching for 10 minutes.

  The side etching rate is a quotient obtained by dividing the area of the bottom surface 41 of the grease holding portion 40 by the area of the opening 31 of the masking member 30, and “1” is a DLC film having the same area as the opening 31. If it is larger than “1”, it indicates that the DLC film is removed more than necessary (side etching state), and if it is smaller than “1”, the DLC film is removed. Indicates that there is a shortage. Therefore, the side etching rate is desirably “1”.

  The etching rate is the depth of the DLC film etched in 1 minute. After 10 minutes of plasma etching, the etching depth is measured by a step gauge, and the value is divided by 10 minutes of etching time. did.

  As shown in Table 1 and FIG. 5, the side etching rate is 9.4 at a gas pressure of 117 Pa, the side etching rate is 8.6 at a gas pressure of 103 Pa, the side etching rate is 6.3 at a gas pressure of 77 Pa, and the gas pressure is 42 Pa. The side etching rate is 4.0 and the side etching rate is 3.1 at a gas pressure of 37 Pa, which is “1” or more, and thus the DLC film having a larger area than the opening 31 has been removed. At a gas pressure of 26 Pa, a gas pressure of 13 Pa, and a gas pressure of 5 Pa, the side etching rate is 1.0, and the DLC film having the same area as the opening 31 is removed. Therefore, if the gas pressure is 26 Pa or less, the side etching rate is “1”, and a desirable etching result is obtained.

  As shown in Table 1 and FIG. 6, the etching rate is 15 nm / min at a gas pressure of 117 Pa, the etching rate is 35 nm / min at a gas pressure of 103 Pa, the etching rate is 55 nm / min at a gas pressure of 77 Pa, and the etching is performed at a gas pressure of 42 Pa. The rate is 65 nm / min, the etching rate is 70 nm / min at a gas pressure of 37 Pa, the etching rate is 72 nm / min at a gas pressure of 26 Pa, the etching rate is 73 nm / min at a gas pressure of 13 Pa, and the etching rate is 73 nm / min at a gas pressure of 5 Pa. is there. Therefore, at a gas pressure with a side etching rate of “1”, the required processing time for plasma etching a DLC film having a DLC film thickness of 2000 nm is approximately 28 minutes at a gas pressure of 26 Pa, and at a gas pressure of 13 Pa and a gas pressure of 5 Pa. It is about 27 minutes, which is a practical processing time. Therefore, if the gas pressure is 26 Pa or less, etching with a desirable side etching rate can be formed in a practical processing time.

  Next, with reference to Table 2 and FIG. 7, the experimental result about the mixing ratio of Ar to etching gas is described. Table 2 is a table showing the etching rate difference ratios at various Ar mixing ratios, and FIG. 7 is a graph showing the relationship between the Ar mixing ratio and the etching rate difference ratios.

  In this experiment, an etching gas was supplied to the chamber 1 at a gas pressure of 13 Pa, and workpieces were placed at three locations on an A4 size substrate as the cathode 3 and etched for 10 minutes. The workpiece is a substantially cylindrical shaft having a height of 40 mm and a diameter of 10 mm on the substrate. A masking member provided with an opening of 2 mm in diameter at the center of the side surface is covered with a mask clearance of 0.025 mm, and only the opening is covered. Etching was performed. And after completion | finish of an etching, the depth of the etching part of three to-be-processed objects was measured, and the etching rate difference ratio was computed. The etching rate difference ratio is a value obtained by multiplying the quotient obtained by dividing the difference between the maximum etching depth and the minimum etching depth by the average value of the etching depths of the three workpieces by 100. The film thickness of the DLC film is 2000 nm. The workpieces were placed on a straight line forming one diagonal line of an A4 size substrate at substantially equal intervals. In other words, the substrate was placed at three locations, approximately the center of the substrate, one corner, and corners facing each other across the corner.

  As the etching depth of the three workpieces varies, the value of the etching rate difference ratio increases. The variation in the etching depth means that the etching rate varies depending on the mounting position of the workpiece on the substrate, and the time required to remove all the DLC film varies. Therefore, even if the etching of the opening of the masking member is finished in a certain workpiece (first workpiece), the opening of the masking member of the workpiece (second workpiece) placed at another position If the etching is not completed, the etching is further continued, and side etching proceeds on the first workpiece that has already been etched.

  For example, consider a case where etching of all workpieces is completed in 60 minutes. When the etching rate difference ratio is 10%, the workpiece that has been etched earliest is etched in about 54 minutes, and the remaining 6 minutes are further etched. If the etching rate difference ratio is 36%, the workpiece that has been etched earliest is completed in about 41 minutes, and the remaining about 19 minutes are further etched. Therefore, it is desirable that the difference in the etching rate depending on the mounting position of the workpiece is small and the value of the etching rate difference ratio is small. Generally, when the excess time after completion of etching exceeds about 20% of the time required for completion of etching, side etching proceeds. Therefore, the judgment value of the value of the etching rate difference ratio is set to 10%.

  As shown in Table 2 and FIG. 8, when the Ar mixture ratio is 20%, the etching rate difference ratio is 58%, and when the Ar mixture ratio is 50%, the etching rate difference ratio is 36%, which is not desirable because it exceeds 10%. However, the etching rate difference ratio is 10% at an Ar mixing ratio of 70%, the etching rate difference ratio is 7% at an Ar mixing ratio of 90%, and the etching rate difference ratio is 4% at an Ar mixing ratio of 100%. Therefore, it is a desirable Ar mixing ratio. Therefore, the Ar mixing ratio is desirably 70% or more.

  Next, with reference to Table 3 and FIG. 8, Table 4 and FIG. 9, the experimental result about the temperature of a workpiece side surface (DLC film) will be described. Table 1 is a table showing the relationship between the workpiece temperature, the etching rate and the required processing time, and FIG. 8 is a graph showing the relationship between the workpiece temperature and the etching rate. Table 4 is a table showing the relationship between the temperature of the workpiece and the hardness of the DLC film, and FIG. 9 is a graph showing the relationship between the temperature of the workpiece and the hardness of the DLC film.

  In this experiment, using a workpiece on which a DLC film having a thickness of 2000 nm was formed in a state where the temperature in the film forming chamber was 250 ° C., the temperature of the workpiece was set to various temperatures ranging from 40 ° C. to 250 ° C. for 10 minutes. Plasma etching was performed. Note that the Ar mixing ratio of the etching gas is 70%, the gas pressure is 13 Pa, and the mask clearance is 0.025 mm. The temperature of the workpiece was measured by attaching a thermo label to the side surface of the workpiece.

  As shown in Table 3 and FIG. 8, the etching rate at 250 ° C. is 130 nm / min, the processing time required to etch all the 2000 nm DLC films is 15 minutes, and the etching rate at 200 ° C. is 90 nm / min. The required processing time is 22 minutes, the etching rate at 170 ° C. is 73 nm / min and the required processing time is 27 minutes, the etching rate at 130 ° C. is 45 nm / min and the required processing time is 44 minutes, and the etching rate at 100 ° C. is The required processing time is 80 minutes at 25 nm / min, the etching rate at 70 ° C. is 10 nm / min and the required processing time is 200 minutes, the etching rate at 50 ° C. is 6 nm / min and the required processing time is 333 minutes. However, the etching rate at 40 ° C. is 3 nm / min, and the processing time required to etch all of the 2000 nm DLC film is 667 minutes. That is, it takes 11 hours or more, and one etching is not completed in one day working time (for example, 8 hours), which is difficult to say as a practical processing time. However, at 250 ° C. to 50 ° C., the etching is completed in one day working time from 15 minutes to about 5 hours and a half nm / min to etch all of the 2000 nm DLC film. If the temperature is 170 ° C. or higher, the etching is completed in a short period of 15 minutes to 27 minutes and within 30 minutes although energy for increasing the temperature is required. Therefore, from this experimental result, it can be said that the temperature of the workpiece side surface is desirably 50 ° C. or higher.

  In this experiment, only the temperature up to 250 ° C. is measured. This is because when the temperature of the DLC film to be etched is higher than the temperature in the film forming chamber when the DLC film is formed, graphitization of the DLC film proceeds, and the DLC film itself becomes brittle. This is because the workpiece becomes unusable for use. Therefore, an experiment was conducted as to whether or not the DLC film maintains its hardness when the DLC film is heated to a high temperature. The results of this experiment are shown in Table 4 and FIG. The DLC-coated 2000 nm DLC film was heated to each temperature while the temperature in the film formation chamber at the time of forming the DLC film was 250 ° C., and the Vickers hardness was measured after holding at that temperature for 1 hour. For the measurement of Vickers hardness, a micro hardness tester (MVK-E manufactured by Akashi Seisakusho Co., Ltd.), which is a micro Vickers hardness tester, was used.

  As shown in Table 4 and FIG. 9, the Vickers hardness is 2500 Hv at 100 ° C., 130 ° C., 170 ° C., 200 ° C., and 250 ° C., and the hardness before heating is maintained. However, at 290 ° C., the Vickers hardness is 2000 Hv, and at 320 ° C., the Vickers hardness is 1200 Hv, and the hardness before heating is not maintained. In other words, if the temperature is higher than 250 ° C. when etching is performed, even if the etching rate is increased, the DLC film itself becomes fragile. However, it is not desirable that the temperature is too high. Therefore, from this experimental result, it can be said that the temperature on the side surface of the workpiece is desirably 250 ° C. or less, which is the temperature in the film formation chamber during film formation. Therefore, based on the results of these two experiments, it is desirable that the temperature of the side surface of the workpiece when performing plasma etching be equal to or lower than the film formation chamber temperature during film formation. In the DLC film of the present embodiment, The film formation chamber temperature of 250 ° C. or lower and 50 ° C. or higher is desirable.

  Next, with reference to Table 5 and FIG. 10, the experimental results regarding the mask clearance will be described. Table 5 is a table showing the relationship between the mask clearance and the side etching rate, and FIG. 10 is a graph showing the relationship between the mask clearance and the side etching rate.

  In this experiment, using a masking member having a mask clearance of 0.005 mm to 2.0 mm, an etching gas having an Ar mixing ratio of 70% was introduced at a gas pressure of 13 Pa, and the DLC film having a thickness of 2000 nm was applied for 27 minutes. Then, plasma etching was performed, and each side etching rate was calculated. Also in this case, it is desirable that the side etching rate is “1”.

  As shown in Tables 5 and 10, when the mask clearance is 0.005 mm, the masking member cannot be attached to and detached from the workpiece, so that the experiment itself cannot be performed. When the mask clearance is 0.010 mm, 0.025 mm, 0.050 mm, 0.100 mm, 0.500 mm, and 1.000 mm, the DLC film has a side etching rate of 1.0 and the same area as the opening of the masking member. Has been removed. However, when the mask clearance is 1.200 mm, it is 1.7, when the mask clearance is 1.500 mm, 3.2, and when the mask clearance is 2.000 mm, it is 7.8. A large area of the DLC film has been removed. Therefore, the mask clearance is desirably 1.00 mm or less. Moreover, it is desirable that it is more than the distance (for example, 0.005 mm) which can attach or detach a masking member.

From the above experimental results, the pressure of the etching gas is desirably 26 Pa or less, the mixing ratio of Ar of the etching gas, which is a mixed gas of Ar, CF ₄ , and O ₂ , is desirably 70% or more, and the side surface of the workpiece (DLC coating) ) Is preferably equal to or lower than the temperature in the film formation chamber during film formation. In the DLC film of the present embodiment, it is preferably 50 ° C. or higher and 250 ° C. or lower, and the mask clearance is preferably 1 mm or less.

  In addition, the DLC film removal method of this invention is not limited to above-described embodiment, Of course, various changes can be added within the range which does not deviate from the summary of this invention. The shape of the workpiece is not limited to a cylindrical shape, and may be a more complicated shape. Further, the thickness of the DLC film is not limited to 2000 nm, and may be more or less.

  The DLC film removal method of the present invention can be used when a DLC film formed on a member having a sliding portion in various apparatuses and requiring the use of a lubricant is removed by a plasma etching method.

It is the schematic of the chamber 1 of a plasma etching apparatus. 3 is an enlarged view of the surface of the workpiece 10 and the masking member 30. FIG. 3 is an enlarged perspective view of the workpiece 10 covered with the masking member 30 and subjected to plasma etching. FIG. It is sectional drawing of the to-be-processed object 10 and the masking member 30 in the state from which the DLC film was removed by the etching in the A-A 'arrow direction in FIG. It is a graph which shows the relationship between a gas pressure and a side etching rate. It is a graph which shows the relationship between a gas pressure and an etching rate. It is a graph which shows the relationship between Ar mixing ratio and an etching rate difference ratio. It is a graph which shows the relationship between the temperature of a to-be-processed object, and an etching rate. It is a graph which shows the relationship between the temperature of a to-be-processed object, and the hardness of a DLC film. It is a graph which shows the relationship between a mask clearance and a side etching rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Anode 3 Cathode 4 Matching box 5 Power supply 6 Plasma processing space 10 Workpiece 11 Hardened steel 12 Inclined layer 13 DLC coating 30 Masking member 31 Opening part 40 Grease holding part 41 Bottom face 50 Mask clearance

Claims (5)

In a DLC film removal method in which a DLC (Diamond Like Carbon) film formed on the surface of a substrate is partially removed by a plasma etching method,
A method for removing a DLC film, wherein the pressure of an etching gas is 26 Pa or less. The etching gas is a mixed gas of Ar, CF ₄ and O ₂ ,
The method for removing a DLC film according to claim 1, wherein the mixing ratio of Ar is 70% or more.   The method of removing a DLC film according to claim 1 or 2, wherein the temperature of the DLC film when removing the DLC film is equal to or lower than the temperature at which the DLC film is formed in the film forming chamber in which the DLC film is formed.   The method of removing a DLC film according to any one of claims 1 to 3, wherein the temperature of the DLC film when removing the DLC film is 50 ° C or higher and 250 ° C or lower. The method for removing a DLC film according to any one of claims 1 to 4, wherein an interval between the mask that covers a portion where the DLC film is not removed and the DLC film is 1 mm or less.

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