Method for cleaning components for semiconductor manufacturing equipment and method for manufacturing components for semiconductor manufacturing equipment using the same

Abstract

To provide technology related to a method for cleaning semiconductor manufacturing equipment components containing ceramics that does not cause physical damage to the cleaning surface.SOLUTION: By discharging cleaning liquid CL from a discharge port 61 (or outlet 61A) into a first washing tank 20, shear stress is generated by the water flow of the cleaning liquid CL. Furthermore, ultrasonic vibration is applied from an ultrasonic transducer 40. Furthermore, by setting the temperature of the cleaning liquid CL to less than 15°C, the viscosity η of the cleaning liquid CL can be increased compared to when the temperature of the cleaning liquid CL is at room temperature (around 25°C). This can increase the particle removal capacity.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cleaning method for a member for a semiconductor manufacturing apparatus including ceramics and a manufacturing method for a member for a semiconductor manufacturing apparatus using the same.

Background Art

[0002] Patent Document 1 discloses a cleaning method in which a sherbet containing a chemical solution and snow ice is pressed against a substrate to clean the substrate such as a semiconductor wafer.

[0003] Patent Document2 discloses a cleaning method using a high-speed shear flow, in which a shear flow having a constant speed gradient of a certain level or more and having a controlled range and distribution is generated along the surface of the object to be cleaned, thereby removing fine foreign substances adhering to the surface of the object to be cleaned.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the cleaning method described in Patent Document 1, since a sherbet containing snow ice is pressed against the surface (cleaning surface) of the object to be cleaned, it has been difficult to eliminate the physical damage to the cleaning surface associated therewith. In the cleaning method described in Patent Document 2, it is necessary to increase the velocity gradient of the cleaning liquid on the cleaning surface. For that purpose, it is necessary to use a high-pressure nozzle having a small hole diameter (or a narrow slit), and it is necessary to arrange the high-pressure nozzle close to the cleaning surface so that the distance between the high-pressure nozzle and the cleaning surface is about 1 to 2 mm. Therefore, it has been difficult to clean the inner surface of a member having an inner surface, such as a cylindrical member or a member having a hollow portion.

[0006] The object of the present invention is to provide a cleaning method for semiconductor manufacturing equipment components, including ceramics, that does not risk causing physical damage to the cleaning surface, and that can easily clean the inner surface of components having an inner surface, such as cylindrical components or components with hollow sections. [Means for solving the problem]

[0007] According to aspects of the present invention, half For conductor manufacturing equipment ceramics containing A method for cleaning components, The first cleaning tank is placed inside the second cleaning tank, which has an inner diameter larger than the outer diameter of the first cleaning tank. The ultrasonic transducer is positioned inside the second cleaning tank and outside the first cleaning tank. ceramics The components are placed inside the first cleaning tank, The cleaning solution containing ultrapure water is introduced into the first cleaning tank such that the amount of the cleaning solution flowing in is discharged outside the first cleaning tank, while the cleaning solution in the first cleaning tank ceramics By applying ultrasonic vibrations to the member, the ceramics This includes cleaning the components, The cleaning solution is characterized by being at -1°C or below. half For conductor manufacturing equipment ceramics containing A method for cleaning components is provided. [Effects of the Invention]

[0008] In the above embodiment, a cleaning solution containing ultrapure water is introduced into the cleaning tank, thereby generating shear stress due to the water flow of the cleaning solution. Furthermore, ultrasonic vibrations are applied to the component. As a result, the cleaning capacity can be increased compared to cleaning the component using only the shear stress generated by the water flow of the cleaning solution. In addition, by keeping the temperature of the cleaning solution below 15°C, the viscosity of the cleaning solution can be increased compared to when the temperature of the cleaning solution is at room temperature (around 25°C). This increases the shear stress generated by the water flow of the cleaning solution, thereby improving the cleaning capacity and shortening the cleaning time. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of the ultrapure water cleaning system 100. [Figure 2] Figure 2 is a flowchart showing the cleaning method according to this embodiment. [Figure 3] Figure 3 is an example of a graph showing the time change of particle concentration P in the first washing tank 20, as measured by the particle counter 50. [Figure 4] Figure 4 is a graph showing the change in viscosity of ultrapure water with respect to temperature (solid line) and the change in viscosity of a cleaning solution obtained by mixing ultrapure water and ethylene glycol in a weight ratio of 50:50 (dotted line). [Figure 5] Figure 5 is an explanatory diagram illustrating the case of cleaning the inner surface of a cylindrical object 10 that has a hollow interior. [Figure 6] Figure 6 is a table summarizing the results of Examples 1 to 13 and the comparative examples. [Modes for carrying out the invention]

[0010] <Urpure Water Cleaning System 100> A cleaning system 100 according to an embodiment of the present invention will now be described. In the following description, the vertical direction 5 and the horizontal direction 6 are defined based on the state in which the cleaning system 100 is installed for use (the state in Figure 1). The cleaning system 100 is used for cleaning components for semiconductor manufacturing equipment containing ceramics (hereinafter simply referred to as "objects to be cleaned 10"). Examples of objects to be cleaned 10 include ceramic structures used in plasma processes (ceramic sintered bodies such as Al2O3, Y2O3, and SiC, and metal bases with ceramic thermal spray coatings formed on an Al substrate). As shown in Figure 1, the cleaning system 100 according to this embodiment includes a first cleaning tank 20, a second cleaning tank 30, three ultrasonic transducers 40, a particle counter 50, a discharge unit 60, and a cleaning liquid supply device 70.

[0011] The first cleaning tank 20 is a cylindrical plastic cleaning tank. The second cleaning tank 30 is a cylindrical cleaning tank, and an outlet 35 is provided at the bottom of the second cleaning tank 30. The inner diameter of the second cleaning tank 30 is larger than the outer diameter of the first cleaning tank 20, and as shown in Figure 1, the first cleaning tank 20 is positioned inside the second cleaning tank 30. The object to be cleaned 10 is placed inside the first cleaning tank 20. The object to be cleaned 10 is held apart from the bottom surface 22 of the first cleaning tank 20 by a holder (not shown). The first cleaning tank 20 is also held apart from the bottom surface 32 of the second cleaning tank 30. The upper end 21 of the first cleaning tank 20 is located above the upper end 31 of the second cleaning tank 30.

[0012] As shown in Figure 1, one ultrasonic transducer 40 is positioned on the bottom surface 32 of the second cleaning tank 30, and two ultrasonic transducers 40 are positioned on the side surface 33. The two ultrasonic transducers 40 positioned on the side surface 33 are arranged so that the directions of ultrasonic propagation are perpendicular to each other in the horizontal plane. These ultrasonic transducers 40 convert power supplied from an transmitter (not shown) into vibrations to generate ultrasonic waves.

[0013] The particle counter 50 includes a water intake 51 disposed inside the first cleaning tank 20. The water intake 51 samples the cleaning water CL in the first cleaning tank 20. The particle counter 50 measures the concentration P (number of particles / mL) (hereinafter simply referred to as the particle concentration P) of particles contained in the cleaning water CL in the first cleaning tank 20 using the cleaning water CL sampled through the water intake 51. In this specification, the particles mean fine particles having a particle diameter of 0.2 μm or more. The particles are generated, for example, by fine foreign substances adhering to the surface (cleaning surface) of the object to be cleaned 10 or particles constituting the ceramic being detached from the cleaning surface by performing cleaning as described below.

[0014] The discharge unit 60 has a discharge port 61 for discharging the cleaning liquid CL supplied from the cleaning liquid supply device 70 into the first cleaning tank 20, and a temperature sensor 62 for measuring the temperature of the cleaning liquid CL discharged from the discharge port 61. The discharge port 61 is formed by a vinyl chloride pipe (φ50 mm) cut so that the tip is at 45°. The cleaning liquid supply device 70 includes an ultrapure water production device 71, an alcohol addition unit 72, and a temperature regulator 73. The ultrapure water production device 71 is a known ultrapure water production device including a UV irradiation unit, an ion exchange resin, a filter, a resistivity measurement unit, etc., and detailed description thereof is omitted here. Ultrapure water having a resistivity of 18 MΩcm or more is supplied from the ultrapure water production device 71. The alcohol addition unit 72 adds a predetermined amount of alcohol to the ultrapure water supplied from the ultrapure water production device 70 to generate a cleaning liquid CL containing ultrapure water and alcohol. The type and amount of alcohol added by the alcohol addition unit 72 can be adjusted by the user as appropriate. The temperature regulator 73 adjusts the temperature of the cleaning liquid CL to a set temperature. The temperature regulator 83 may be configured to perform feedback control based on the temperature of the cleaning liquid CL measured by the temperature sensor 62 to keep the temperature of the cleaning liquid CL constant.

[0015] Next, a cleaning method for the object 10 to be cleaned using the cleaning system 100 will be described while referring to FIG. 2. First, the object 10 to be cleaned is placed inside the first cleaning tank 20 (S11). As described above, it is held in a state separated from the bottom surface 22 of the first cleaning tank 20 by a holder (not shown) (see FIG. 1). Next, the cleaning liquid CL supplied from the cleaning liquid supply device 70 is discharged from the discharge port 61 into the first cleaning tank 20 at a predetermined flow rate Q (L / min) (S12). Incidentally, the step of placing the object 10 to be cleaned inside the first cleaning tank 20 (S11) and the step of discharging the cleaning liquid CL supplied from the cleaning liquid supply device 70 into the first cleaning tank 20 from the discharge port 61 at a flow rate of Q (m 3 / min) (S12) can be interchanged.

[0016] The first cleaning tank 20 is not provided with an outlet such as the outlet 35 of the second cleaning tank 30. Therefore, after the first cleaning tank 20 is full of water, the cleaning liquid CL overflows from the upper end 21 of the first cleaning tank 20. As shown in FIG. 1, since the second cleaning tank 30 is arranged below the first cleaning tank 20, the cleaning liquid CL overflowing from the upper end 21 of the first cleaning tank 20 flows into the second cleaning tank 30. Incidentally, in order to prevent the cleaning liquid CL from overflowing from the second cleaning tank 30, a part of the cleaning liquid CL flowing into the second cleaning tank 30 flows out from the outlet 35. The cleaning liquid CL flowing out from the outlet 35 is recovered by a recovery mechanism (not shown). When the cleaning liquid CL is ultrapure water, the recovered cleaning liquid CL is supplied to the ultrapure water production device 71 as raw water for ultrapure water and reused.

[0017] Next, the ultrasonic transducer 40 is driven to apply ultrasonic vibrations to the object to be cleaned 10 (S13). As described above, since the first cleaning tank 20 is made of plastic, the ultrasonic waves propagated through the cleaning liquid CL filling the second cleaning tank 30 can pass through the first cleaning tank 20 and reliably reach the object to be cleaned 10 placed inside the first cleaning tank 20. Furthermore, since the ultrasonic transducer 40 is positioned on the bottom surface 32 and two mutually orthogonal parts of the side surface 33 of the second cleaning tank 30, ultrasonic waves can be applied to the object to be cleaned 10 from multiple directions (in this case, three directions). It is also possible to arrange two ultrasonic transducers 40 facing each other on the side surface 33. However, compared to applying ultrasonic vibrations to the object to be cleaned 10 from mutually opposing directions, as in this embodiment, the unevenness in the intensity of the ultrasonic vibrations can be reduced.

[0018] While applying ultrasonic vibrations, the particle concentration P in the first cleaning tank 20 is measured using the particle counter 50 (S14). As described above, in this specification, particles refer to fine particles with a particle diameter of 0.2 μm or more. In this embodiment, the particle counter 50 detects the concentration of fine particles with a particle diameter of 0.2 μm or more. It goes without saying that the measurement of the particle concentration P can be started before applying ultrasonic vibrations. Alternatively, as a cleaning procedure, the cleaning solution CL may be filled into the first cleaning tank 20 and the second cleaning tank 30, and then the object to be cleaned 10 may be placed in the first cleaning tank 20 and ultrasonic vibrations may be applied. In this case, the starting point of the cleaning time is when the ultrasonic vibrations are applied. Alternatively, ultrasonic vibrations may be applied after filling the first cleaning tank 20 and the second cleaning tank 30 with the cleaning solution CL, and then the object to be cleaned 10 may be placed in the first cleaning tank 20. In this case, the starting point of the cleaning time is when the object to be cleaned 10 is placed in the first cleaning tank 20.

[0019] Figure 3 is an example of a graph showing the time change of particle concentration P in the first cleaning tank 20, as measured by the particle counter 50. The horizontal axis of the graph shows the elapsed time since the start of measurement of particle concentration P, and the vertical axis shows the number of particles contained in 1 mL of cleaning solution CL. Ultrasonic vibration is applied 2 minutes after the start of measurement. Immediately after the application of ultrasonic vibration, the particle concentration P rises sharply, and reaches a maximum after time Tm has elapsed since the application of ultrasonic vibration. Subsequently, the particle concentration P gradually decreases, and after time Tc has elapsed since the particle concentration P reached its maximum, the particle concentration P has decreased to 20% of the maximum value. In this embodiment, cleaning is determined to be complete when the particle concentration P has decreased to 20% of the maximum value. In the following description, the time Tm from the start of application of ultrasonic vibration until the particle concentration P reaches its maximum value is referred to as the arrival time Tm. Furthermore, the time Tc from when the particle concentration P reaches its maximum until it decreases to 20% of that maximum value is called the decay time Tc.

[0020] To shorten the cleaning time, it is necessary to shorten the arrival time Tm and the decay time Tc. However, since the decay time Tc is longer than the arrival time Tm, shortening the decay time Tc is effective. According to the inventors' findings, the decay time Tc can be shortened by increasing the shear stress τ (hereinafter simply referred to as shear stress τ) caused by the water flow of the cleaning liquid CL. This is thought to be because increasing the shear force on the cleaning surface of the object to be cleaned 10 suppresses the reattachment of particles that have peeled off the cleaning surface of the object to be cleaned 10 to the cleaning surface.

[0021] The shear stress τ due to the water flow of the cleaning solution CL is expressed as the product of the viscosity η (Pa·s) of the cleaning solution and the gradient du / dy (1 / s) of the velocity u of the water flow in the direction y normal to the cleaning surface (τ = η·du / dy). From this, it can be seen that the shear stress τ increases as the viscosity η of the cleaning solution increases. Figure 4 is a graph showing the temperature dependence of viscosity for ultrapure water used as the cleaning solution CL and a mixture of ultrapure water and ethylene glycol. As can be seen from the graph in Figure 4, the viscosity η of the cleaning solution CL can be increased by using a mixture of ultrapure water and ethylene glycol as the cleaning solution CL than by using ultrapure water as the cleaning solution CL. Furthermore, in both cases, the viscosity η of the cleaning solution CL can be increased by lowering the temperature of the cleaning solution CL.

[0022] Furthermore, in this invention, particles are not removed solely by the shear stress caused by the water flow of the cleaning solution CL, but also by the simultaneous application of ultrasonic vibrations. Because the ultrasonic vibrations assist the shear force caused by the water flow of the cleaning solution CL, the ability to remove particles from the cleaning surface can be enhanced. [Examples]

[0023] The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited to the examples and comparative examples described below. In common to the examples and comparative examples described below, an ultrasonic transducer 40 with a frequency of 150 kHz and an output of 1000 W was used. In addition, a liquid particle counter (KS42-A) manufactured by Rion Co., Ltd. was used as the particle counter 50. The measurement range was set to 0.2 μm or larger to measure the concentration of fine particles with a particle diameter of 0.2 μm or larger.

[0024] [Example 1] In Example 1, a cylindrical alumina ceramic with an outer diameter of 416 mm, an inner diameter of 400 mm, and a height of 100 mm was used as the object to be cleaned 10. Ultrapure water was used as the cleaning solution CL. The temperature of the cleaning solution CL was set to 13°C, and the flow rate Q of the cleaning solution CL was set to 20 L / min.

[0025] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 60 min.

[0026] [Example 2] In Example 2, the same washing material 10 as in Example 1 was used. Ultrapure water was used as the washing solution CL. The temperature of the washing solution CL was set to 8°C, and the flow rate Q of the washing solution CL was set to 20 L / min.

[0027] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 50 min.

[0028] [Example 3] In Example 3, the same washing material 10 as in Example 1 was used. As the washing solution CL, a washing solution was used which was a mixture of ultrapure water and methanol, a monohydric alcohol, in a weight ratio of 50:50. The temperature of the washing solution CL was set to 8°C, and the flow rate Q of the washing solution CL was set to 20 L / min.

[0029] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 35 min.

[0030] [Example 4] In Example 4, the same washing material 10 as in Example 1 was used. Ultrapure water was used as the washing solution CL. The temperature of the washing solution CL was set to -1°C, and the flow rate Q of the washing solution CL was set to 20 L / min.

[0031] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 40 min.

[0032] [Example 5] In Example 5, the same washing material 10 as in Example 1 was used. As the washing solution CL, a washing solution was used which was a mixture of ultrapure water and methanol, a monohydric alcohol, in a weight ratio of 50:50. The temperature of the washing solution CL was set to -1°C, and the flow rate Q of the washing solution CL was set to 20 L / min.

[0033] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 26 min.

[0034] [Example 6] In Example 6, the same washing material 10 as in Example 1 was used. Ultrapure water was used as the washing solution CL. The temperature of the washing solution CL was set to -10°C, and the flow rate Q of the washing solution CL was set to 20 L / min.

[0035] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 33 min.

[0036] [Example 7] In Example 7, a cylindrical alumina ceramic with an outer diameter of 25 mm, an inner diameter of 20 mm, and a height of 200 mm was used as the object to be cleaned 10. Ultrapure water was used as the cleaning solution CL. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 7, as shown in Figure 5, when cleaning the inner surface of the object to be cleaned 10, a discharge port 61A formed by a resin tube with an outer diameter of 12 mm and an inner diameter of 10 mm was used instead of the discharge port 61 described above. The cleaning solution CL discharged from the discharge port 61A was directed toward the inner surface of the cylindrical object to be cleaned 10 so that the cleaning solution CL discharged from the discharge port 61A flowed along the inner surface of the cylindrical object to be cleaned 10.

[0037] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 12 min.

[0038] [Example 8] In Example 8, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and methanol, a monohydric alcohol, in a weight ratio of 50:50. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 8, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0039] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 10 min.

[0040] [Example 9] In Example 9, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and ethylene glycol, a dihydric alcohol, in a weight ratio of 50:50. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 9, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0041] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 7 min.

[0042] [Example 10] In Example 10, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and glycerin, a trivalent alcohol, in a weight ratio of 50:50. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 10, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0043] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 5 min.

[0044] [Example 11] In Example 11, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and ethylene glycol, a dihydric alcohol, in a weight ratio of 80:20. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 11, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0045] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 9 min.

[0046] [Example 12] In Example 12, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and ethylene glycol, a dihydric alcohol, in a weight ratio of 70:30. The temperature of the cleaning solution CL was set to -5°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 12, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0047] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 8 min.

[0048] [Example 13] In Example 13, the same object to be cleaned 10 as in Example 7 was used. As the cleaning solution CL, a cleaning solution was used which was a mixture of ultrapure water and ethylene glycol, a dihydric alcohol, in a weight ratio of 50:50. The temperature of the cleaning solution CL was set to -10°C, and the flow rate Q of the cleaning solution CL was set to 5 L / min. In Example 13, as in Example 7, when cleaning the inner surface of the object to be cleaned 10, the discharge port 61A was used instead of the discharge port 61.

[0049] Under these conditions, when the particle concentration in the first washing tank 20 was measured in real time during washing, the decay time Tc was 4 min.

[0050] [Comparative Example] The comparative example is the same as in Example 1, except that the temperature of the ultrapure water used as the cleaning solution CL is at room temperature (27°C). Similar to Example 1, the particle concentration in the first cleaning tank 20 was measured in real time during cleaning, and the decay time Tc was 110 min.

[0051] <Summary of Examples and Comparative Examples> Figure 6 shows a table summarizing the results of Examples 1 to 13 and the Comparative Example described above. As can be seen by comparing Examples 1 to 11 with the Comparative Example, the decay time Tc could be reduced to 60 min or less by lowering the temperature of the cleaning solution CL to below 15°C. Also, as can be seen by comparing Examples 1, 2, 4, and 6, when ultrapure water is used as the cleaning solution CL, the decay time Tc could be reduced by lowering the temperature of the cleaning solution CL. Furthermore, as can be seen from the comparison of Examples 3 and 5, and Examples 9 and 13, when using a cleaning solution CL obtained by adding alcohol to ultrapure water, the decay time Tc could also be reduced by lowering the temperature of the cleaning solution CL.

[0052] As can be seen from the comparison of Examples 2 and 3, Examples 4 and 5, and Examples 7 and 8, adding alcohol to ultrapure water as the washing solution CL reduces the decay time Tc compared to using ultrapure water. Furthermore, as can be seen from the comparison of Examples 8, 9, and 10, when adding alcohol, using an alcohol with a large molecular weight reduces the decay time Tc compared to using an alcohol with a small molecular weight. The molecular weight of methanol (Example 8) is 32.0, the molecular weight of ethylene glycol (Example 9) is 62.1, and the molecular weight of glycerin (Example 10) is 92.1.

[0053] As can be seen by comparing Examples 9, 11, and 12, when alcohol is added to ultrapure water as a washing solution, the decay time Tc could be reduced as the mixing ratio of alcohol to ultrapure water increased.

[0054] As can be seen by comparing Examples 8-10, adding divalent and trivalent alcohols to ultrapure water as a washing solution is more effective in reducing the decay time Tc than adding monovalent alcohols to ultrapure water. Furthermore, adding trivalent alcohols to ultrapure water as a washing solution is more effective in reducing the decay time Tc than adding divalent alcohols to ultrapure water. In other words, it was found that increasing the valency and molecular weight of the alcohol increases the effect of reducing the decay time Tc.

[0055] <Effects of the Embodiment> In the above embodiment, the cleaning liquid CL is discharged from the discharge port 61 (or discharge port 61A) into the first cleaning tank 20, thereby generating shear stress due to the water flow of the cleaning liquid CL. Furthermore, by applying ultrasonic vibrations from the ultrasonic transducer 40, the particle removal capability (cleaning capability) is enhanced.

[0056] As described above, the shear stress τ due to the water flow of the cleaning solution CL is expressed as the product of the viscosity η (Pa·s) of the cleaning solution and the gradient du / dy (1 / s) of the velocity u of the water flow in the direction y normal to the cleaning surface (τ = η·du / dy). Therefore, if the viscosity η of the cleaning solution CL can be increased, the shear stress τ due to the water flow of the cleaning solution CL can be increased. By increasing the shear stress τ due to the water flow of the cleaning solution CL, the particle removal capacity can be improved and the decay time Tc can be shortened. In this embodiment, by lowering the temperature of the cleaning solution CL to below 15°C, the viscosity η of the cleaning solution CL is increased compared to when the temperature of the cleaning solution CL is at room temperature (around 25°C) (see Figure 4). This increases the shear stress τ due to the water flow of the cleaning solution CL, improving the particle removal capacity and thus reducing the decay time Tc (for example, to 60 min or less). In this embodiment, even when the temperature of the cleaning solution CL is lowered to below 15°C, the cleaning solution CL maintains its liquid phase. Since the cleaning solution CL is not in a sherbet-like state, there is no risk of causing physical damage to the cleaning surface of the object 10 during cleaning.

[0057] In the above embodiment, ultrapure water or a mixture of ultrapure water and alcohol is used as the cleaning solution CL. Ultrapure water can maintain its liquid phase even in a supercooled state below 0°C. Furthermore, a mixture of ultrapure water and alcohol can maintain its liquid phase even at temperatures lower than the freezing point of ultrapure water due to molar freezing point depression. Therefore, in the above embodiment, whether ultrapure water or a mixture of ultrapure water and alcohol is used as the cleaning solution CL, the temperature of the cleaning solution CL can be kept below 0°C. This allows the viscosity η of the cleaning solution CL to be increased compared to when the temperature of the cleaning solution CL is higher than 0°C. Consequently, the shear stress τ due to the water flow in the cleaning solution CL can be increased, improving the particle removal ability and thus reducing the decay time Tc.

[0058] In this embodiment, the cleaning solution CL used is one of the following: a cleaning solution obtained by mixing ultrapure water with a monohydric alcohol such as methanol; a cleaning solution obtained by mixing ultrapure water with a dihydric alcohol such as ethylene glycol; or a cleaning solution obtained by mixing ultrapure water with a trihydric alcohol such as glycerin. By using a cleaning solution CL obtained by mixing ultrapure water with these alcohols, the viscosity η can be increased compared to a cleaning solution CL containing only ultrapure water. Furthermore, when using a cleaning solution CL obtained by mixing ultrapure water with these alcohols, it is possible to lower the temperature to an even lower temperature than the freezing point of ultrapure water, thereby increasing the viscosity η. By increasing the viscosity η, the shear stress τ caused by the water flow in the cleaning solution CL can be increased, thereby improving the particle removal ability and reducing the decay time Tc.

[0059] In the above embodiment, when cleaning the inner surface of a hollow cylindrical object 10, the cleaning liquid CL was discharged from the discharge port 61A toward the inner surface of the cylindrical object 10 so that the cleaning liquid CL flowed along the inner surface of the cylindrical object 10 (see Figure 5). This allows a shear stress τ caused by the water flow of the cleaning liquid CL to be applied to the inner surface of the cylindrical object 10, making it possible to easily clean the inner surface.

[0060] In the above embodiment, the particle concentration P (concentration of particles with a particle diameter of 0.2 μm or more) in the first washing tank 20 is measured using a particle counter 50 while the object to be washed 10 is being washed. Since the washing can be terminated after confirming that the particle concentration P in the first washing tank 20 has decreased sufficiently, the object to be washed 10 can be reliably washed. Furthermore, since the particle concentration P can be measured in real time using the particle counter 50, the time until the end of washing can be shortened compared to a batch washing method in which the particle concentration P is measured after washing for a certain period of time and re-washing is performed as needed.

[0061] <Change form> The embodiments described above are merely illustrative and can be modified as appropriate. For example, the shape and dimensions of the first cleaning tank 20 and the second cleaning tank 30 are not limited to the above embodiments and can be any shape and dimensions. For example, the first cleaning tank 20 and the second cleaning tank 30 can be rectangular parallelepipeds. In the above embodiments, the first cleaning tank 20 was made of plastic, taking into consideration the transmission of ultrasonic waves. However, the present invention is not limited to such embodiments, and cleaning tanks of any material can be used as long as ultrasonic waves can be transmitted through them.

[0062] In the above embodiment, of the three ultrasonic transducers 40, one ultrasonic transducer 40 was positioned on the bottom surface 32 of the second cleaning tank 30, and the remaining two ultrasonic transducers were positioned on the side surface 33 facing each other. The present invention is not limited to such disclosure, and the number and arrangement of the ultrasonic transducers 40 can be arbitrarily set. For example, one ultrasonic transducer 40 may be positioned in the second cleaning tank 30 so that ultrasonic waves are applied to the object to be cleaned 10 from one direction, or multiple ultrasonic transducers 40 may be positioned in the second cleaning tank 30 so that ultrasonic waves are applied from three or more intersecting directions.

[0063] In the above embodiment, the particle counter 50 measured the particle concentration P in the first washing tank 20 in real time, but the present invention is not limited to such an embodiment. The particle counter 50 may measure the particle concentration P in the first washing tank 20 intermittently (for example, every few seconds).

[0064] In the above embodiment, two types of discharge ports 61 and 61A were used interchangeably. However, the present invention is not limited to this embodiment, and the shape of the discharge port can be arbitrarily adjusted according to the shape of the cleaning surface of the object to be cleaned 10.

[0065] The cleaning method for semiconductor manufacturing equipment components containing ceramics described in the above embodiment can be incorporated into a method for manufacturing such semiconductor manufacturing equipment components containing ceramics. In other words, a method for manufacturing semiconductor manufacturing equipment components containing ceramics can use the cleaning method for semiconductor manufacturing equipment components containing ceramics described in the above embodiment as part of the cleaning process.

[0066] Although embodiments and modified versions of the invention have been described above, the technical scope of the present invention is not limited to the scope described above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is also clear from the claims that such modified or improved forms may be included in the technical scope of the present invention.

[0067] The order in which each process in the manufacturing method shown in the specification and drawings is executed is not specifically defined, and unless the output of a previous process is used in a later process, the processes can be executed in any order. Even if phrases such as "first," and "next," are used for convenience, this does not mean that the processes must be performed in that order. [Explanation of Symbols]

[0068] 10 Items to be washed 20 First Washing Tank 30 Second washing tank 40 Ultrasonic transducers 50 Particle Counter 60 Discharge part 100 Ultrapure Water Cleaning Systems

Claims

1. A method for cleaning ceramic-containing members for semiconductor manufacturing equipment, The first cleaning tank is placed inside the second cleaning tank, which has an inner diameter larger than the outer diameter of the first cleaning tank. The ultrasonic transducer is placed inside the second cleaning tank and outside the first cleaning tank. The ceramic-containing member is placed inside the first cleaning tank, The method includes: flowing the cleaning solution containing ultrapure water into the first cleaning tank such that the inflow rate of the cleaning solution is discharged outside the first cleaning tank, while applying ultrasonic vibrations to the ceramic-containing member in the first cleaning tank with the ultrasonic transducer to clean the ceramic-containing member; A method for cleaning ceramic-containing components for semiconductor manufacturing equipment, characterized in that the cleaning solution is at -1°C or below.

2. The cleaning solution comprises at least one alcohol selected from the group consisting of monohydric alcohols, dihydric alcohols, and trihydric alcohols, as described in claim 1, for cleaning a ceramic-containing member for a semiconductor manufacturing apparatus.

3. The ceramic-containing member has a cylindrical shape with a hollow interior, and has an inner surface that defines the hollow portion. A method for cleaning a ceramic-containing member for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein when cleaning the ceramic-containing member, the cleaning liquid is introduced into the hollow portion such that the cleaning liquid flows along the inner surface of the ceramic-containing member.

4. Furthermore, the concentration of particles with a particle size of 0.2 μm or larger in the first washing tank is measured, A method for cleaning a ceramic-containing member for a semiconductor manufacturing apparatus according to any one of claims 1 to 3, comprising adjusting the cleaning time for cleaning the ceramic-containing member based on the concentration of particles in the first cleaning tank.

5. A method for manufacturing a ceramic-containing member for semiconductor manufacturing equipment, A method for manufacturing a ceramic-containing member for semiconductor manufacturing equipment, comprising cleaning the ceramic-containing member by the cleaning method described in any one of claims 1 to 4.

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