wafer cleaning equipment

Abstract

This invention provides a wafer cleaning apparatus that removes resin adhering to the outer periphery of a wafer without using cleaning equipment. The wafer cleaning apparatus cleans the outer periphery of a wafer, comprising a cleaning unit that sprays high-pressure water towards the outer periphery of the wafer from a position outside the holding surface of the holding table. The cleaning unit includes: a first nozzle that sprays high-pressure water towards the outer periphery of the wafer from a position outside the outer periphery of the wafer in a direction parallel to the holding surface; a second nozzle that sprays high-pressure water towards the outer periphery of the wafer in a direction 45 degrees downward relative to the holding surface; and a third nozzle that sprays high-pressure water towards the outer periphery of the wafer in a direction 45 degrees upward relative to the holding surface.

Description

Technical Field

[0001] This invention relates to a wafer cleaning apparatus. Background Technology

[0002] In wafer manufacturing, wafers with undulations or warps can be obtained by slicing semiconductor ingots. In order to remove undulations and warps from the wafer, as disclosed in Patent Document 1, a protective member composed of resin and a sheet is formed on one side of the wafer.

[0003] Furthermore, the wafer is held on one side by a chuck stage through a protective component, and the other side of the wafer is ground by a grinding wheel to remove undulations and warping.

[0004] After grinding the other side of the wafer, as disclosed in Patent Document 2, the protective component is removed, and one side of the wafer is ground. In this way, a wafer of a specified thickness is manufactured.

[0005] When the protective component is peeled off from the wafer, resin sometimes remains on the outer periphery (edge) of the wafer. Therefore, as disclosed in Patent Document 3, the outer periphery of the wafer is cleaned with a cleaning device to remove the attached resin.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-168565

[0007] Patent Document 2: Japanese Patent Application Publication No. 2018-098241

[0008] Patent Document 3: Japanese Patent Application Publication No. 2019-047054

[0009] However, in traditional cleaning methods, the sponge used as a cleaning tool is consumed, thus incurring replacement costs for the cleaning tool. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide a wafer cleaning apparatus that can remove resin adhering to the outer periphery of a wafer without using cleaning equipment.

[0011] According to the present invention, a wafer cleaning apparatus is provided for cleaning the outer periphery of a wafer. The wafer cleaning apparatus includes: a holding stage that holds the wafer with a holding surface such that the outer periphery of the wafer protrudes; a motor that rotates the holding stage about the center of the holding surface; a rotation control unit that controls the rotation speed of the motor; and a cleaning unit that sprays high-pressure water from a position outside the outer periphery of the wafer held by the holding surface toward the outer periphery of the wafer to clean the outer periphery of the wafer. The cleaning unit includes: a first nozzle that sprays high-pressure water from a position outside the outer periphery of the wafer held by the holding surface toward the outer periphery of the wafer. A first nozzle, a second nozzle, and a third nozzle are arranged to spray high-pressure water onto the outer periphery of the wafer from a position slightly outside the outer periphery, in a 0-degree direction parallel to the holding surface; a second nozzle is positioned slightly above the outer periphery of the wafer, in a 45-degree downward direction relative to the holding surface; and a third nozzle is positioned slightly below the outer periphery of the wafer, in a 45-degree upward direction relative to the holding surface. The first, second, and third nozzles are arranged to be separated from each other in the circumferential direction of the wafer.

[0012] Preferably, the cleaning unit is configured to spray high-pressure water by mixing water and air and utilizing the pressure of air.

[0013] Preferably, the rotation control unit is configured such that after the outer periphery of the wafer is cleaned by rotating the holding stage at a rotational speed of 10 rpm or less, the holding stage is rotated at a rotational speed of 1000 rpm or more to dry the wafer.

[0014] In this wafer cleaning apparatus, high-pressure water is sprayed onto the outer periphery of the wafer from three different directions, thoroughly cleaning the periphery and removing resin and other adhering substances. Therefore, this wafer cleaning apparatus eliminates the need for consumable cleaning tools such as sponges for cleaning the outer periphery. This eliminates the need for tool replacement, thus avoiding the costs associated with tool replacement. Attached Figure Description

[0015] Figure 1 This is a side view showing the structure of a wafer cleaning apparatus.

[0016] Figure 2 It is a top view showing the wafer, the holding table, and the nozzles of the cleaning unit.

[0017] Figure 3 This is a side view showing other structures of the wafer cleaning apparatus.

[0018] Label Explanation

[0019] 1: Wafer cleaning apparatus; 10: Holding table; 11: Holding surface; 12: Center point; 13: Spindle; 15: Motor; 17: Rotation control unit; 20: Cleaning unit; 21: First nozzle; 22: Air source; 23: Water source; 24: Second nozzle; 25: Air source; 26: Water source; 27: Third nozzle; 28: Air source; 29: Water source; 30: Cleaning control unit; 40: Air nozzle; 100: Wafer; 101: Outer periphery. Detailed Implementation

[0020] like Figure 1 As shown, the wafer cleaning apparatus 1 of this embodiment is used to clean the outer periphery 101 of the wafer 100. The outer periphery 101 has rounded corners because it is formed in an arc shape from one side of the wafer 100 to the other.

[0021] Furthermore, the wafer 100 has already undergone grinding, which has removed the protective component previously formed on one surface of the wafer 100. Therefore, contaminants such as resin, which are the material used as the protective component, are adhered to the outer periphery 101 of the wafer 100. In the wafer cleaning apparatus 1, this resin and other contaminants are removed by cleaning the outer periphery 101 of the wafer 100.

[0022] The wafer cleaning apparatus 1 includes a holding stage 10 for holding a wafer 100. The holding stage 10 has a holding surface 11 smaller than the wafer 100. This holding surface 11 is made of, for example, a porous material and is connected to an attraction source (not shown) to attract and hold the wafer 100. Therefore, the holding stage 10 holds the wafer 100 through the holding surface 11 with the outer periphery 101 of the wafer 100 protruding.

[0023] The wafer cleaning apparatus 1 also includes: a spindle 13 disposed on the lower surface of the holding table 10; a motor 15 that rotates the spindle 13; and a rotation control unit 17 that controls the rotation speed of the motor 15.

[0024] The spindle 13 is configured to rotate about the center of the holding surface 11. The motor 15 rotates the spindle 13, thereby enabling the holding table 10 to rotate about the center of the holding surface 11 as shown by arrow 200.

[0025] The wafer cleaning apparatus 1 also has a cleaning unit 20 outside the outer periphery 101 of the wafer 100 held by the holding surface 11 of the holding stage 10. The cleaning unit 20 sprays high-pressure water from a position outside the outer periphery of the wafer 100 held by the holding surface 11 toward the outer periphery 101 of the wafer 100, for example toward the center in the thickness direction of the outer periphery 101, thereby cleaning the outer periphery 101 of the wafer 100.

[0026] like Figure 1 As shown, the cleaning unit 20 has three nozzles: a first nozzle 21, a second nozzle 24, and a third nozzle 27.

[0027] like Figure 1 As shown by the middle arrow 201, the first nozzle 21 sprays high-pressure water onto the outer periphery 101 of the wafer 100 from a position outside the outer periphery 101 of the wafer 100 along a 0-degree direction parallel to the holding surface 11 of the holding table 10.

[0028] like Figure 1 As shown by the middle arrow 202, the second nozzle 24 sprays high-pressure water onto the outer periphery 101 of the wafer 100 from a position above and to the outside of the outer periphery 101 of the wafer 100, in a direction 45 degrees downward relative to the holding surface 11 of the holding table 10.

[0029] like Figure 1 As shown by the middle arrow 203, the third nozzle 27 sprays high-pressure water onto the outer periphery 101 of the wafer 100 from a position slightly below and to the outside of the outer periphery 101 of the wafer 100, in a direction 45 degrees upward relative to the holding surface 11 of the holding table 10.

[0030] In addition, such as Figure 2 As shown, the first nozzle 21, the second nozzle 24 and the third nozzle 27 are arranged in the circumferential direction of the wafer 100, for example, in a manner that separates them from each other at 10-degree intervals.

[0031] The high-pressure water ejected from the first nozzle 21, the second nozzle 24 and the third nozzle 27 is directed, for example, toward the center point 12, which is the radial center of the holding surface 11 (the center of the wafer 100), on the horizontal plane (the plane parallel to the holding surface 11).

[0032] In addition, the cleaning unit 20 is configured to spray high-pressure water by mixing water and air and utilizing the pressure of air.

[0033] That is, such as Figure 1 As shown, the first nozzle 21 is connected to the air source 22 and the water source 23, the second nozzle 24 is connected to the air source 25 and the water source 26, and the third nozzle 27 is connected to the air source 28 and the water source 29.

[0034] Furthermore, the first nozzle 21, the second nozzle 24, and the third nozzle 27 are configured to generate high-pressure water (i.e., high-pressure water composed of a mixture of water and air, i.e., dual-fluid cleaning water) by mixing water from their respective water sources 23, 26, and 29 with air from their respective air sources 22, 25, and 28, and then spray the high-pressure water.

[0035] Thus, nozzle 21, nozzle 24, and nozzle 27 function as dual-fluid cleaning nozzles. In addition, nozzle 21, nozzle 24, and nozzle 27 are configured to spray only air from each of the air sources 22, 25, and 28, and also to spray only water from each of the water sources 23, 26, and 29.

[0036] The cleaning unit 20, comprising the first nozzle 21, the second nozzle 24, and the third nozzle 27, is composed of... Figure 1 The cleaning control unit 30 shown is used for control.

[0037] Next, the operation of the wafer cleaning apparatus 1 will be explained.

[0038] [Cleaning Action]

[0039] First, a cleaning operation is performed. In this operation, the wafer 100 is held using the holding surface 11 of the holding stage 10.

[0040] Subsequently, the cleaning control unit 30 supplies water from water sources 23, 26, and 29 at a rate of, for example, 40 ml / min to the first nozzle 21, the second nozzle 24, and the third nozzle 27, and supplies air from air sources 22, 25, and 28 at a rate of, for example, 70 l / min. The first nozzle 21, the second nozzle 24, and the third nozzle 27 generate high-pressure water composed of two-fluid cleaning water by mixing the supplied water with the air, and begin spraying high-pressure water onto the outer periphery 101 of the wafer 100 in the respective spray directions set above.

[0041] Next, the rotation control unit 17 controls the motor 15 to rotate the holding stage 10, which holds the wafer 100 using the holding surface 11, one revolution at a speed of 10 rpm or less (e.g., 1 rpm). This completes the cleaning of the wafer 100, and the rotation control unit 17 stops the rotation of the holding stage 10 based on the motor 15. Simultaneously, the cleaning control unit 30 stops supplying water and air to the first nozzle 21, the second nozzle 24, and the third nozzle 27. Through this cleaning action, resin and other contaminants adhering to the outer periphery 101 of the wafer 100 are removed.

[0042] In addition, in this embodiment, rotating the wafer 100 once means that the wafer 100 rotates so that the three high-pressure water jets ejected from the first nozzle 21, the second nozzle 24 and the third nozzle 27 spray onto the entire outer periphery 101 of the wafer 100.

[0043] Here, as Figure 2 As shown, the first nozzle 21, the second nozzle 24, and the third nozzle 27 are arranged to be separated from each other in the circumferential direction of the wafer 100. Therefore, the rotation angle of one revolution increases by the amount of the angle range according to the nozzle arrangement, starting from 360 degrees.

[0044] For example, with the first nozzle 21, the second nozzle 24, and the third nozzle 27 arranged at 10-degree intervals in the circumferential direction of the wafer 100, rotating the wafer 100 one revolution means rotating the wafer 100 approximately 380 degrees.

[0045] [Drying action]

[0046] Next, the drying operation is performed. During the drying operation, firstly, the rotation control unit 17 controls the motor 15 to rotate the holding stage 10, which holds the wafer 100 via the holding surface 11, at a speed of 1000 rpm or higher (e.g., 2000 rpm) for, for example, 20 seconds. During this time, for the first 15 seconds, no air or other spraying from the cleaning unit 20 is performed; the rotation of the holding stage 10 holding the wafer 100 causes water adhering to the wafer 100 to disperse. Alternatively, the rotation of the holding stage 10 may not be stopped during the cleaning operation, but the rotation speed may be switched to the drying operation speed immediately after the cleaning operation.

[0047] Furthermore, after 15 seconds from the start of the rotation of the stage 10, the cleaning control unit 30 supplies air from air sources 22, 25, and 28 to the first nozzle 21, the second nozzle 24, and the third nozzle 27 within 5 seconds, initiating the spraying of air onto the wafer 100 from these nozzles. During these 5 seconds, air is supplied to the rotating wafer 100 from three directions, promoting the drying of the wafer 100.

[0048] Five seconds after the start of air supply, i.e., 20 seconds after the start of the drying operation, the drying of the wafer 100 is considered complete, and the rotation control unit 17 stops the rotation of the holding table 10 based on the motor 15. At the same time, the cleaning control unit 30 stops supplying air to the first nozzle 21, the second nozzle 24, and the third nozzle 27.

[0049] As described above, in this embodiment, by spraying high-pressure water onto the outer periphery 101 of the wafer 100 from three different directions, the outer periphery 101 with rounded corners can be thoroughly cleaned, removing resin and other contaminants adhering to it. Therefore, in this embodiment, cleaning equipment such as sponges, which are consumables, is not required for cleaning the outer periphery 101. Thus, there is no need to replace cleaning equipment, thereby avoiding the costs associated with replacing cleaning equipment.

[0050] In this embodiment, during the drying process, air is sprayed onto the wafer 100 from the first nozzle 21, the second nozzle 24, and the third nozzle 27. Relatedly, the wafer cleaning apparatus 1 can also be configured as follows: Figure 3The device also includes an air nozzle 40. The air nozzle 40 is configured to be positioned above the center of the wafer 100 held by the holding surface 11 of the holding stage 10, and to spray air onto the wafer 100 as shown by arrow 205.

[0051] In this case, during the drying operation, the cleaning control unit 30 sprays air towards the wafer 100 from the air nozzle 40 instead of spraying air from the first nozzle 21, the second nozzle 24, and the third nozzle 27, or based on this method. This directs air from the air nozzle 40 towards the center of rotation of the wafer 100, thus shortening the drying time. Alternatively, air can be sprayed towards the outer periphery of the holding stage 10 to dry the lower surface of the wafer 100.

[0052] In this embodiment, during the cleaning operation, the rotation control unit 17 rotates the holding stage 10 holding the wafer 100 one revolution. However, the rotation control unit 17 can also rotate the holding stage 10 two revolutions or more, or rotate it 360 degrees.

[0053] Furthermore, in this embodiment, during the drying operation, after 15 seconds of drying achieved solely by rotating the worktable 10, a 5-second drying process is performed that incorporates air jets from the cleaning unit 20. Regarding this, the drying time achieved solely by rotating the worktable 10 and the drying time with added air jets can be arbitrarily set.

[0054] In this embodiment, the first nozzle 21, the second nozzle 24, and the third nozzle 27 each have air sources 22, 25, and 28, and water sources 23, 26, and 29, respectively. Alternatively, the first nozzle 21, the second nozzle 24, and the third nozzle 27 may be configured to communicate with a shared air source and water source.

Claims

1. A wafer cleaning apparatus for cleaning the outer periphery of a wafer, wherein, This wafer cleaning device has the following features: A holding stage holds the wafer by means of a holding surface that protrudes from the outer periphery of the wafer; An electric motor causes the holding table to rotate about the center of the holding surface as an axis; A rotation control unit that controls the rotational speed of the electric motor; and The cleaning unit sprays high-pressure water from a position outside the outer periphery of the wafer held by the holding surface towards the outer periphery of the wafer to clean the outer periphery of the wafer. The cleaning unit includes: The first nozzle sprays high-pressure water onto the outer periphery of the wafer from a position further outward than the outer periphery of the wafer, in a 0-degree direction parallel to the holding surface. The second nozzle sprays high-pressure water onto the outer periphery of the wafer from a position above and to the outside of the outer periphery, at a 45-degree angle downward relative to the holding surface. as well as The third nozzle, positioned slightly below and to the outside of the wafer's outer periphery, sprays high-pressure water at a 45-degree angle upward relative to the holding surface onto the outer periphery of the wafer. When viewed from above the wafer, the first nozzle, the second nozzle, and the third nozzle are arranged sequentially in a manner that separates them from each other in the circumferential direction of the wafer to spray high-pressure water onto the outer periphery of the wafer.

2. The wafer cleaning apparatus according to claim 1, wherein, This cleaning unit sprays high-pressure water using the pressure of air by mixing water and air.

3. The wafer cleaning apparatus according to claim 1, wherein, The rotation control unit is configured such that after cleaning the outer periphery of the wafer by rotating the holding stage at a rotational speed of less than 10 rpm, the holding stage is rotated at a rotational speed of more than 1000 rpm to dry the wafer.

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