Cleaning method and cleaning apparatus
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- YAMAHA ROBOTICS HLDG CO LTD
- Filing Date
- 2025-01-17
- Publication Date
- 2026-07-30
Smart Images
Figure 2026123658000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technology of spin cleaning.
Background Art
[0002] Spin cleaning is used as a method for chemically and mechanically wet cleaning semiconductor products such as wafers. When drying the cleaned wafer, the table supporting the wafer is rotated at high speed to shake off the cleaning liquid on the wafer by centrifugal force (see, for example, Patent Documents 1 and 2). When centrifugal force is applied, the liquid film of the cleaning liquid moves radially from the center to the outer periphery, so a circular dry area is formed at the rotation center, and the dry area expands radially over time.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0004] For high - bandwidth memory (HBM: High Bandwidth Memory) whose demand is increasing due to the progress of AI technology and the like, it is produced by processes such as chip - on - wafer (CoW) that stack semiconductor chips vertically using through - silicon vias (TSV: Through Sillicon Via) and the like.
[0005] In such processes, a step is created between the wafer, which serves as the support, and the semiconductor chip mounted on it. Therefore, when centrifugal force is applied, even if the cleaning solution on the top surface of the semiconductor chip is drained, the cleaning solution tends to remain in the valleys between adjacent semiconductor chips. The cleaning solution contains foreign matter such as particles that have fallen off the semiconductor chips. When the remaining cleaning solution evaporates, there is a risk that such foreign matter will adhere to the wafer.
[0006] The present invention has been made in view of these circumstances, and aims to provide a technology for a cleaning method suitable for workpieces with steps on their surface. [Means for solving the problem]
[0007] A cleaning method according to one aspect of the present invention includes the steps of: cleaning the surface of a workpiece by supplying liquid from a discharge unit while rotating the workpiece; and rotating the workpiece to move the liquid and expand the dry area from the center to the outer periphery of the workpiece, wherein the workpiece is a support on which a plurality of semiconductor chips are mounted, and in the step of expanding the dry area, the dry area has a first area on the support and a second area on the plurality of semiconductor chips that expands ahead of the first area, and is characterized in that liquid is supplied from the discharge unit while moving the discharge unit in accordance with the expansion of the first area.
[0008] Another aspect of the present invention is a cleaning apparatus comprising a turntable for rotating a workpiece and a discharge unit for supplying liquid to the surface of a workpiece, wherein the cleaning apparatus is configured to clean the surface of the workpiece by supplying liquid from the discharge unit while rotating the workpiece, to move the liquid by rotating the workpiece, and to expand the dry area from the center to the outer periphery of the workpiece, wherein the workpiece is a support on which a plurality of semiconductor chips are mounted, and when the dry area is expanded, the dry area has a first area on the support and a second area on the plurality of semiconductor chips that expands before the first area, and the cleaning apparatus is characterized in that it supplies liquid from the discharge unit while moving the discharge unit in accordance with the expansion of the first area. [Effects of the Invention]
[0009] According to the present invention, it is possible to provide a technology for a cleaning method suitable for workpieces with steps on their surface. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a cross-sectional view showing an example of a cleaning apparatus used in a cleaning method according to one embodiment of the present invention. [Figure 2] Figure 2 is a plan view showing the surface of an example of the workpiece shown in Figure 1. [Figure 3] Figure 3 is a flowchart illustrating an example of a cleaning method according to one embodiment of the present invention. [Figures 4A-4F] Figures 4A to 4F are cross-sectional views illustrating a series of operations of the cleaning apparatus shown in Figure 1. [Figure 5A] Figure 5A is a plan view showing an example of a workpiece being drained using conventional technology. [Figure 5B] Figure 5B is a cross-sectional view of the workpiece shown in Figure 5A. [Modes for carrying out the invention]
[0011] Preferred embodiments of the present invention will be described with reference to the attached drawings. In each figure, components denoted by the same reference numerals have the same or similar configuration. The present invention will be described in detail below with reference to the drawings. Figure 1 is a cross-sectional view showing an example of a cleaning apparatus 10 used in a cleaning method according to one embodiment of the present invention.
[0012] The cleaning device 10 can clean the surface of the workpiece 60 (spin cleaning) by supplying liquid 90 from the nozzle 34 while rotating the workpiece 60. After cleaning, the workpiece 60 can be rotated to shake off the liquid 90 from the surface of the workpiece 60 by centrifugal force.
[0013] In the illustrated example, the cleaning device 10 includes a turntable 20 for rotating the workpiece 60, a first arm 30 to which a nozzle 34 is attached, a second arm 40 for holding the wipe material 44, a detection unit 50 for sensing the surface condition of the workpiece 60, and the like. The second arm 40 is not an essential component of the present invention and may be omitted.
[0014] In the illustrated example, the turntable 20 includes a rotary drive unit 21, a rotary shaft 22, a turntable 23, etc. The rotary shaft 22 passes through a waste liquid tray 19 for collecting the liquid used for cleaning. The lower end of the rotary shaft 22 is connected to the rotary drive unit 21. The upper end of the rotary shaft 22 is connected to the turntable 23.
[0015] The rotating disc 23 is formed in a circular, flat plate shape. The rotating base 20 transmits the driving force generated by the rotation drive unit 21 via the rotating shaft 22 to rotate the workpiece 60 placed on the upper surface of the rotating disc 23. The configuration of the rotating base 20 is not limited to the illustrated example and may be modified as appropriate.
[0016] In the illustrated example, the first arm 30 further includes, in addition to the nozzle 34 described above, an arm body 31, an XY drive unit 32, an ultrasonic oscillator 33, and the like. The nozzle 34 is positioned above the turntable 20 and discharges liquid 90 onto the surface of the workpiece 60 placed on the turntable 23. The nozzle 34 is an example of a discharge unit that supplies liquid.
[0017] Liquid 90 can be selected from a variety of options as long as it washes away foreign matter from the workpiece 60. Liquid 90 may also be called a cleaning solution 90. One example of such liquid 90 is hydrogen water, which is obtained by dissolving hydrogen in water so that its saturation level at atmospheric pressure is 60% to 100%. The nozzle 34 is connected to a hydrogen water production device or the like. Liquid 90 may also be ammonia-added hydrogen water, which is obtained by adding ammonia to hydrogen water. Liquid 90 is not limited to hydrogen water and may be other liquids.
[0018] In the illustrated example, an ultrasonic oscillator 33 is attached to the outer peripheral surface of the nozzle 34. The ultrasonic oscillator 33 ultrasonically vibrates the nozzle 34, enabling the nozzle 34 to spray hydrogen water containing microbubbles onto the surface of the workpiece 60. The nozzle 34 is attached to the tip of the arm main body 31. The base end of the arm main body 31 is connected to the XY drive unit 32.
[0019] Due to the driving force of the XY drive unit 32, the arm main body 31 swings around the base end of the arm main body 31, and the nozzle 34 attached to the tip of the arm main body 31 moves horizontally parallel to the surface of the workpiece 60. The configuration of the first arm 30 is not limited to the illustrated example and may be changed as appropriate.
[0020] In the illustrated example, in addition to the wiping material 44 described above, the second arm 40 further includes an arm main body 41, an XY drive unit 42, a Z drive unit 43, etc. The wiping material 44 takes in and removes fine foreign matter adhering to the surface of the workpiece 60, and is configured with a multilayer structure including a sheet material capable of adsorbing foreign matter, a cushion material capable of compression deformation, etc. The wiping material 44 is attached to the Z drive unit 43. The tip of the arm main body 41 is connected to the Z drive unit 43. The base end of the arm main body 41 is connected to the XY drive unit 42.
[0021] Due to the driving force of the XY drive unit 42, the arm main body 41 swings around the base end of the arm main body 41, and the wiping material 44 attached to the tip of the arm main body 41 moves horizontally along the surface of the workpiece 60. The Z drive unit 43 moves the wiping material 44 in the vertical direction to bring a part of the wiping material 44 into contact with the surface of the workpiece 60. The configuration of the second arm 40 is not limited to the illustrated example and may be changed as appropriate.
[0022] The detection unit 50 is, for example, an infrared camera or a high-speed camera. By processing the image data with a computer, the extent of the liquid 90 spread on the surface of the workpiece 60 can be detected. The infrared camera utilizes the infrared absorption wavelength unique to the liquid 90 to obtain image data in which dry areas 64 without liquid 90 on the surface of the workpiece 60 are displayed brightly, and liquid film areas with liquid 90 are displayed darkly. The high-speed camera captures images at a video rate of 1000fps or higher to obtain clear image data of the workpiece 60 rotating at high speed. The high-speed camera may be an infrared high-speed camera or a visible light high-speed camera.
[0023] If the detection unit 50 is permanently attached to the cleaning device 10, the surface condition of the workpiece 60 can be sensed in real time, and the cleaning device 10 can be operated based on the results of the sensing. The detection unit 50 may be attached to the cleaning device 10 only when necessary and removed from the cleaning device 10 at other times. If the detection unit 50 is attached to the cleaning device 10 as needed, the detection unit 50 can be attached to collect sampling data of the expansion speed of the first region 74, which will be described later, and after collection, the detection unit 50 can be removed and the cleaning device 10 can be operated based on the sampling data.
[0024] Figure 2 is a plan view showing the surface of an example of the workpiece 60 shown in Figure 1. The workpiece 60 consists of multiple semiconductor chips 80 mounted on a support 70, with a step between the top surface and the valleys of the semiconductor chips 80. The semiconductor chips 80 are formed by dicing a wafer into individual pieces.
[0025] The support 70 may be an adhesive tape such as a dicing tape that supports the semiconductor chip 80, a wafer sliced from a silicon single crystal, or a printed circuit board such as a flexible printed circuit board or a rigid printed circuit board. The workpiece 60 that is the target of the cleaning step S1 and the dewatering step S2 has such a support 70 exposed from the gaps between adjacent semiconductor chips 80. In the illustrated example, the support 70 is a wafer, and the workpiece 60 is configured as a DRAM with semiconductor chips 80 stacked on the wafer.
[0026] Figure 3 is a flowchart illustrating an example of a cleaning method according to one embodiment of the present invention. As shown in Figure 3, the cleaning method first cleans the surface of the workpiece 60 by supplying liquid 90 from a nozzle 34 while rotating the workpiece 60 (cleaning step S1). Next, the workpiece 60 is rotated to move the liquid 90, and the dry area 64 from which the liquid 90 has been removed expands from the center 62 of the workpiece 60 toward the outer periphery 63 (dewatering step S2).
[0027] Figure 5A is a plan view showing an example of a workpiece 60 being drained using the conventional technology, and Figure 5B is a cross-sectional view thereof. As shown in Figures 5A and 5B, in a workpiece 60 with steps on its surface, such as when multiple semiconductor chips 80 are mounted on a support 70, the drying region 84 on the upper surface of the semiconductor chips 80 (hereinafter referred to as the "second region 84") expands earlier than the drying region 74 on the support 70 that is exposed from the valleys between the semiconductor chips 80 (hereinafter referred to as the "first region 74").
[0028] In the dewatering process S2, a difference arises between the drainage rate on the support 70 and the drainage rate on the upper surface of the semiconductor chip 80, resulting in a problem where the liquid 90 used for cleaning tends to remain in the first region 74 where drainage is delayed. To solve this problem, the cleaning apparatus 10 of the present invention is characterized in that the nozzle 34 is moved in accordance with the movement of the outer edge 75 of the first region 74.
[0029] The following will provide a more detailed explanation with reference to Figures 4A to 4F. Figures 4A to 4F are cross-sectional views illustrating a series of operations of the cleaning device 10 shown in Figure 1. The nozzle 34 is driven by the aforementioned XY drive unit 32 and can follow the movement of the outer edge 75 of the first region 74. In the illustrated example, the nozzle 34 is positioned directly above the outer edge 75 of the first region 74 and moves horizontally in accordance with the movement of the outer edge 75. The position of the nozzle 34 only needs to be approximately the same as the position of the outer edge 75, and may be slightly outside or slightly inside the outer edge 75 in the radial direction.
[0030] The first region 74 is a dry region 74 on the support 70, as described above, and the outer edge 75 of the first region 74 is the boundary between the dry region 74 and the liquid film region 76 on the support 70. The second region 84 is a dry region 84 on the upper surface of the multiple semiconductor chips 80, and the outer edge 85 of the second region 84 is the boundary between the dry region 84 and the liquid film region 86 on the upper surface of the multiple semiconductor chips 80.
[0031] When the first region 74 expands, it means that the outer edge 75 of the first region 74 moves from the center 62 of the workpiece 60 toward the outer periphery 63 of the workpiece 60, and the outer edge 75 moves away from the rotation center 61. Similarly, when the second region 84 expands, it means that the outer edge 84 of the second region 84 moves from the center 62 of the workpiece 60 toward the outer periphery 63, and the outer edge 85 moves away from the rotation center 61. The center 62 of the workpiece 60 includes the rotation center 61 and its vicinity. The outer periphery 63 of the workpiece 60 includes the outer edge of the workpiece 60 and its vicinity.
[0032] The expansion of the second region 84 precedes the expansion of the first region 74, meaning that the outer edge 85 of the second region 84 is located radially outward of the workpiece 60 than the outer edge 75 of the first region 74. The first region 74 may also be referred to as the lower layer, and the second region 84 as the upper layer.
[0033] According to the cleaning method shown in Figures 3 and 4A to 4F, as the first region 74 expands, the liquid 90 is discharged, supplying liquid to the upper surface of the semiconductor chip 80 and reducing the difference in drainage speed between the upper surface and the valleys. When the upper surface and the valleys of the semiconductor chip 80 are continuously connected by the liquid 90, it becomes less likely for the liquid 90 used for cleaning to remain in the valleys.
[0034] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially substitute or combine the configurations shown in different embodiments.
[0035] [Note 1] The cleaning method includes a step (S1) of supplying liquid (90) from a discharge unit (34) while rotating the workpiece (60) to clean the surface of the workpiece (60), and a step (S2) of rotating the workpiece (60) to move the liquid (90) and expand the dry region (64) from the center (62) of the workpiece (60) toward the outer periphery (63). The workpiece (60) is a support (70) on which a plurality of semiconductor chips (80) are mounted, and in the step (S2) of expanding the dry region (64), the dry region (64) has a first region (74) on the support (70) and a second region (84) on the plurality of semiconductor chips (80) that expands ahead of the first region (74), and is characterized in that the liquid (90) is supplied from the discharge unit (34) while moving the discharge unit (34) in accordance with the expansion of the first region (74).
[0036] [Note 6] The cleaning device (10) comprises a turntable (20) for rotating a workpiece (60) and a discharge unit (34) for supplying liquid (90) to the surface of the workpiece (60). The cleaning device (10) is configured to rotate the workpiece (60) while supplying liquid (90) from the discharge unit (34) to clean the surface of the workpiece (60), and to rotate the workpiece (60) to move the liquid (90), thereby expanding the dry area (64) from the center (62) of the workpiece (60) toward the outer periphery (63). The workpiece (60) is made up of a support (70) on which multiple semiconductor chips (80) are mounted, and when the drying region (64) is expanded, the drying region (64) has a first region (74) on the support (70) and a second region (84) on the multiple semiconductor chips (80) that expands ahead of the first region (74), and the cleaning device (10) is characterized by supplying liquid (90) from the discharge unit (34) while moving the discharge unit (34) in accordance with the expansion of the first region (74).
[0037] In workpieces (60) with stepped surfaces, such as those with multiple semiconductor chips (80) mounted on a support (70), the second region (84) expanding on the upper surface of the semiconductor chips (80) precedes the first region (74) expanding in the valleys between the semiconductor chips (80), resulting in a problem where the cleaning liquid (90) tends to remain in the valleys where drainage is delayed. According to these embodiments, since the liquid (90) is discharged as the first region (74) expands, liquid is supplied to the upper surface of the semiconductor chips (80), reducing the difference in drainage speed between the upper surface and the valleys. When the upper surface and the valleys of the semiconductor chips (80) are continuously connected by the liquid (90), the cleaning liquid (90) is less likely to remain in the valleys, making it suitable for cleaning workpieces (60) with stepped surfaces.
[0038] [Note 2] In Appendix 1, the expansion of the first region (74) may be sensed in real time, and the discharge unit (34) may be moved based on the results of the sensing.
[0039] According to this embodiment, even if the expansion speed changes due to the influence of climate or other factors, it is possible to respond more flexibly compared to a method that does not constantly sense, and therefore the discharge unit (34) can be moved without delay as the first region (74) expands.
[0040] [Note 3] In Appendix 1, sampling data for the expansion of the first region (74) may be collected in advance, and the discharge unit (34) may be moved based on the sampling data.
[0041] According to this embodiment, since equipment such as cameras can be installed only when sampling is required and removed after data collection, the amount of equipment required to implement the present invention can be reduced compared to methods of continuous sensing.
[0042] [Note 4] In appendices 1 to 3, the expansion of the first region (74) may be detected based on data captured by an infrared camera.
[0043] [Note 5] In appendices 1 to 3, the expansion of the first region (74) may be detected based on data captured by a high-speed camera.
[0044] According to these embodiments, the expansion of the first region (74) can be detected with high accuracy, and therefore the present invention can be suitably implemented. [Explanation of Symbols]
[0045] 10...Washing device, 19...Waste water tray, 20...Rotating table, 21...Rotating drive unit, 22...Rotating shaft, 23...Rotating disc, 30...First arm, 31...Arm body, 32...XY drive unit, 33...Ultrasonic oscillator, 34...Nozzle, 40...Second arm, 41...Arm body, 42...XY drive unit, 43...Z drive unit, 44...Wipe material, 50...Detection unit, 60...Workpiece, 61...Rotation center, 62...Center, 63...Peripheral part, 64...Drying area, 70...Support, 74...Drying area on the support, 75...Outer edge of the drying area on the support, 76...Liquid film area on the support, 80...Semiconductor chip, 84...Drying area on the semiconductor chip, 85...Outer edge of the drying area on the semiconductor chip, 86...Liquid film area on the semiconductor chip, 90...Liquid, S1...Washing process, S2...Dewatering process.
Claims
1. A step of cleaning the surface of the workpiece by supplying liquid from a discharge unit while rotating the workpiece, The process includes rotating the workpiece to move the liquid, thereby expanding the dry area from the center of the workpiece toward the outer periphery, The aforementioned workpiece has multiple semiconductor chips mounted on a support, In the step of expanding the drying region, the drying region comprises a first region on the support and a second region on the plurality of semiconductor chips that expands prior to the first region, and the liquid is supplied from the discharge unit while moving the discharge unit in accordance with the expansion of the first region. Cleaning method.
2. The expansion of the first region is sensed in real time, and the discharge unit is moved based on the results of the sensing. The cleaning method according to claim 1.
3. Sampling data for the expansion of the first region is collected in advance, and the discharge unit is moved based on the sampling data. The cleaning method according to claim 1.
4. Based on data captured by an infrared camera, the expansion of the first region is detected. The cleaning method according to claim 1.
5. The expansion of the first region is detected based on data captured by a high-speed camera. The cleaning method according to claim 1.
6. A turntable for rotating the workpiece, A cleaning device comprising a discharge unit for supplying liquid to the surface of the workpiece, The workpiece is rotated while a liquid is supplied from the discharge unit to clean the surface of the workpiece. The workpiece is rotated to move the liquid, and the dry area from which the liquid has been removed is expanded from the center of the workpiece toward the outer periphery. The aforementioned workpiece has multiple semiconductor chips mounted on a support, When the drying region is expanded, the drying region comprises a first region on the support and a second region on the plurality of semiconductor chips that expands prior to the first region. The cleaning device is characterized in that it supplies liquid from the discharge part while moving the discharge part as the first area expands. Washing device.