Wafer cleaning method and cleaning control system

Abstract

The application discloses a wafer cleaning method and a cleaning control system, and the wafer cleaning method comprises the following steps: placing a wafer to be cleaned in a cleaning device, and vertically supporting the wafer by a supporting part; moving a cleaning brush towards the wafer to abut against a surface of the wafer, and rotating the wafer around an axis by the supporting part; spraying a cleaning liquid towards the surface of the wafer by a spray rod in the cleaning device, and absorbing the cleaning liquid on the surface of the wafer by the cleaning brush and rotating the brush to remove particulate matters on the surface of the wafer; wherein when the spray nozzle and / or the spray hole of the spray rod sprays the cleaning liquid, the spray flow of the spray rod section with the same spray direction as the rotation direction of the wafer is greater than the spray flow of the spray rod section with the opposite spray direction as the rotation direction of the wafer.

Description

Technical Field

[0001] This invention belongs to the field of wafer cleaning technology, and more specifically, relates to a wafer cleaning method and a cleaning control system. Background Technology

[0002] The integrated circuit industry is the core of the information technology industry, playing a crucial role in promoting the digital and intelligent transformation and upgrading of the manufacturing industry. Chips are the carriers of integrated circuits, and chip manufacturing involves processes such as chip design, wafer fabrication, wafer processing, electrical measurement, dicing, packaging, and testing. Among these, chemical mechanical polishing (CMP) is a wafer fabrication process, a globally planarizing ultra-precision surface processing technology.

[0003] After chemical mechanical polishing (CMP), wafers require post-processing such as cleaning and drying. The purpose of cleaning is to prevent contamination of semiconductor devices by trace ions and metal particles, ensuring the performance and yield of the semiconductor devices. Wafer cleaning methods include roller cleaning and megasonic cleaning, among which roller cleaning is more widely used. In roller cleaning, the wafer is placed on support rollers on the housing, and roller brushes (cleaning brushes) positioned on both sides of the wafer roll around their axis to contact and remove particles from the wafer surface.

[0004] The key to roller brush cleaning is the proper supply of cleaning solution to the wafer surface. Existing cleaning equipment uses a supply pipe that sprays the cleaning solution through nozzles located on the outer wall. The nozzle's placement and displacement are fixed, and its supply pressure is dependent on the plant conditions, resulting in an unreasonable distribution of the cleaning solution on the wafer surface, failing to effectively remove particles. Furthermore, due to the improper nozzle placement, the cleaning solution on the wafer surface cannot make sufficient contact with the roller brush and is directly discharged, increasing wafer manufacturing costs. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems existing in the prior art.

[0006] Therefore, a first aspect of the present invention provides a wafer cleaning method, comprising:

[0007] S1, Place the wafer to be cleaned in the cleaning device, with the support vertically supporting the wafer;

[0008] S2, the cleaning brush moves toward the wafer to abut against the wafer surface, and the support part drives the wafer to rotate around the axis;

[0009] S3, the spray bar in the cleaning device sprays cleaning fluid toward the wafer surface, and the cleaning brush absorbs the cleaning fluid on the wafer surface and rotates to remove particles from the wafer surface.

[0010] When the nozzle and / or orifice of the spray bar sprays cleaning fluid, the spray flow rate of the spray bar section with the same spray direction as the wafer rotation direction is greater than the spray flow rate of the spray bar section with the opposite spray direction to the wafer rotation direction.

[0011] In some embodiments, the cleaning fluid enters from the end of the spray bar and is sprayed through nozzles and / or orifices spaced apart along the length of the spray bar.

[0012] In some embodiments, the cleaning fluid is supplied from the middle position of the spray bar and sprayed through nozzles and / or orifices located on both sides of the supply position.

[0013] In some embodiments, the nozzle is configured with an independent supply line that can move along the length of the spray bar to adjust the spray position of the cleaning fluid.

[0014] In some embodiments, the nozzles are asymmetrically distributed along the length of the spray bar, and the nozzle spacing corresponding to the spray bar segment with the same spray direction as the wafer rotation direction is smaller than the nozzle spacing corresponding to the spray bar segment with the opposite spray direction to the wafer rotation direction.

[0015] In some embodiments, the nozzles are spaced apart along the axial direction of the spray bar.

[0016] In some embodiments, the nozzles at the center of the spray bar are distributed along a quadratic curve, which is a curve with the midpoint of the spray bar as its axis of symmetry.

[0017] In some embodiments, the nozzle spacing at the middle position of the spray bar is smaller than the nozzle spacing at other positions of the spray bar.

[0018] In some embodiments, the diameter of the nozzle at the middle position of the spray bar is larger than the diameter of the nozzles at other positions of the spray bar.

[0019] In some embodiments, the diameter of the nozzles at the middle position of the spray bar and at the end of the spray bar segment with the same rotation direction as the wafer is larger than the diameter of the nozzles at other positions of the spray bar.

[0020] In some embodiments, the diameter of the nozzle gradually increases from the middle position of the nozzle rod towards the nozzle rod section that is in the same direction as the wafer rotation.

[0021] Furthermore, a second aspect of the present invention provides a cleaning control system, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the wafer cleaning method described above.

[0022] The beneficial effects of the present invention include: the spray bar supplying the cleaning fluid is equipped with nozzles and / or spray holes, and the spray flow rate of the nozzles and / or spray holes is set according to the rotation direction of the wafer to ensure that the distribution of the cleaning fluid is relatively reasonable and to avoid the violent splashing of the cleaning fluid from affecting the cleaning effect of the wafer. Attached Figure Description

[0023] The advantages of the present invention will become clearer and easier to understand through the following detailed description in conjunction with the accompanying drawings, which are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0024] Figure 1 This is a flowchart of a wafer cleaning method provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a cleaning device provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of a cleaning brush vertically cleaning a wafer according to an embodiment of the present invention;

[0027] Figure 4A This is a schematic diagram of a spray bar provided in an embodiment of the present invention;

[0028] Figure 4B This is a schematic diagram of a spray bar provided in another embodiment of the present invention;

[0029] Figure 5A This is a schematic diagram of the cleaning fluid being supplied at the middle position of the self-spraying bar according to an embodiment of the present invention;

[0030] Figure 5B This is a schematic diagram of the cleaning fluid being supplied at the middle position of the self-spraying bar according to another embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of a spray bar provided in another embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of a spray bar provided in other embodiments of the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0034] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0035] In this invention, a wafer (W) is also called a substrate, which has the same meaning and practical function.

[0036] Figure 1 This is a flowchart of a wafer cleaning method provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a cleaning apparatus 100 for post-processing wafer surfaces. The following is in conjunction with... Figure 2 The steps of the wafer cleaning method are described, including:

[0037] S1, the wafer to be cleaned is placed in the cleaning device 100, and the support part 20 vertically supports the wafer;

[0038] Figure 2 In this process, the cleaning device 100 includes a housing 10, inside which a support 20 is provided to vertically support and position the wafer W to be cleaned. Cleaning brushes 30 are provided on both sides of the wafer W, and a drive motor (not shown) is connected to the end of each cleaning brush 30, causing the cleaning brush 30 to rotate around its axis. A spray bar 40 is provided on the upper part of the housing 10 to spray cleaning fluid onto the wafer W.

[0039] During wafer cleaning, the support portion 20 rotates, and under the action of friction, the wafer W, which is vertically mounted on the support portion 20, rotates around the wafer's axis. Specifically, the support portion 20 includes a driving roller and a driven roller, and the driving roller and the driven roller are provided with slots, in which the wafer is engaged; under the action of friction, the rotation of the driving roller can drive the vertically supported wafer W to rotate around its axis.

[0040] Furthermore, deionized water is introduced into the cleaning brush 30 from its end to wet its surface. The cleaning brush 30 can be made of a porous material, such as polyvinyl alcohol, and can absorb a large amount of cleaning solution used to clean the surface of the wafer W.

[0041] S2, the cleaning brush 30 moves toward the wafer to abut against the wafer surface, and the support 20 drives the wafer to rotate around the axis;

[0042] The cleaning brush 30 moves toward the wafer W, and the outer periphery of the cleaning brush 30 abuts against the wafer surface. The active roller of the support part 20 rotates, which can drive the vertically supported wafer W to rotate around the axis. The rolling cleaning brush 30 contacts the rotating wafer W to remove contaminants from the surface of the wafer W.

[0043] S3, the spray bar 40 sprays cleaning fluid toward the wafer surface, the cleaning fluid flows on the wafer surface and works in combination with the cleaning brush 30 to remove particulate matter from the wafer surface;

[0044] Specifically, the spray bar 40 disposed in the housing 10 sprays cleaning fluid toward the wafer surface, and the cleaning brush 30 can absorb a large amount of cleaning fluid for brushing the wafer W surface. The cleaning brush 30 with the cleaning fluid adsorbed cleans the wafer surface in contact.

[0045] Furthermore, the cleaning fluid is sprayed from the nozzle and / or orifice of the spray bar 40, and the spray flow rate is related to the rotation direction of the wafer W. Figure 3 The diagram shows a side view of the cleaning brush 30 contacting and cleaning a vertically positioned wafer W. During the cleaning process, the wafer rotates counterclockwise. The cleaning fluid sprayed by the first spray bar segment L1 of the spray bar 40 is in the same direction as the wafer W's rotation, allowing the cleaning fluid to quickly enter the contact area between the cleaning brush 30 and the wafer W. The cleaning fluid sprayed by the second spray bar segment L2 of the spray bar 40 is in the opposite direction to the wafer W's rotation. Due to the centrifugal force generated by the wafer's rotation, the used cleaning fluid is usually discharged through segment B2 of the cleaning brush 30. Therefore, the spray flow rate of the second spray bar segment L2 should not be too high. If the spray flow rate of the second spray bar segment L2 is too high, the sprayed cleaning fluid will hinder the rapid discharge of the used cleaning fluid. Furthermore, the cleaning fluid sprayed by the second spray bar segment L2 will produce violent sputtering, which is detrimental to the stable cleaning effect on the wafer surface.

[0046] In this invention, the spray flow rate of the spray bar segment where the cleaning fluid is sprayed in the same direction as the wafer rotation direction needs to be greater than the spray flow rate of the spray bar segment where the cleaning fluid is sprayed in the opposite direction to the wafer rotation direction. That is, the spray flow rate of the first spray bar segment L1 needs to be greater than the spray flow rate of the second spray bar segment L2 to ensure the cleaning effect of the wafer and avoid violent splashing of the cleaning fluid.

[0047] The wafer cleaning method described above rationally distributes the cleaning solution supply, ensuring a roughly uniform distribution of the cleaning solution on the rotating wafer surface. This helps remove particulate matter from the wafer surface and guarantees a good cleaning effect. This also helps avoid waste of cleaning solution to some extent, thus controlling wafer manufacturing costs.

[0048] Furthermore, the rotation direction of segment B1 of the cleaning brush 30 is the same as the rotation direction of the wafer W, while the rotation direction of segment B2 is opposite to that of the wafer W. If the rotation speed of a certain part of segment B1 of the cleaning brush 30 is the same as the rotation speed of the wafer, then there is no relative speed between the cleaning brush 30 and the wafer W at that part, making it impossible to clean that part properly. The first spray bar segment L1 corresponds to segment B1 of the cleaning brush 30. The first spray bar segment L1 of the spray bar 40 supplies a large flow of cleaning fluid. The large amount of cleaning fluid can rinse away the locally residual particles, causing them to detach from the wafer surface and preventing particles from remaining between the cleaning brush 30 and the wafer W, thus ensuring the cleaning effect of the wafer.

[0049] Figure 3 In the illustrated embodiment, the cleaning fluid can be supplied from the end of the spray bar 40, which is provided with a plurality of nozzles 40a at intervals. The cleaning fluid enters the interior of the spray bar 40 through the end of the spray bar 40 and is then sprayed onto the surface of the wafer W by the nozzles 40a.

[0050] The spray bar 40 has pre-drilled mounting holes for installing nozzles 40a at predetermined intervals. Since these mounting holes require pre-machining, this somewhat affects the flexibility of adjusting the position of the nozzles 40a. To address this technical issue, the nozzles 40a can be equipped with independent supply lines located inside the spray bar 40. The outer peripheral wall of the spray bar 40 has elongated holes along its axial direction, allowing the nozzles 40a to move along these holes, thus enabling accurate and flexible adjustment of the cleaning fluid supply position.

[0051] It is understandable that spray holes 40b can also be provided on the outer peripheral wall of the spray bar 40, such as... Figure 4A and Figure 4B As shown, the cleaning fluid is supplied from the end of the spray bar 40 so that it can be sprayed from the nozzle 40b toward the wafer surface.

[0052] In another embodiment of the present invention, the cleaning fluid is supplied from the middle position of the spray bar 40, such as... Figure 5A and Figure 5B As shown, the cleaning fluid is sprayed from the nozzle 40b toward the wafer surface. The supply position of the cleaning fluid directly affects the effect of the spray onto the wafer W. Due to the velocity attenuation problem of the fluid transported in the pipeline, supplying the cleaning fluid from the middle position of the spray bar 40 can alleviate the fluid velocity attenuation problem to a certain extent. It can be understood that multiple nozzles 40a can also be provided at intervals on the outer peripheral wall of the spray bar 40, and the cleaning fluid supplied from the middle can be transported toward the first spray bar section L1 and the second spray bar section L2 of the spray bar 40, and sprayed onto the wafer surface from the nozzles 40a thereon.

[0053] In addition, the present invention also discloses a cleaning device, such as Figure 2 As shown, it includes:

[0054] Support portion 20, which is disposed in housing 10 and vertically supports the wafer;

[0055] Cleaning brush 30 is used to clean both the front and back sides of the wafer;

[0056] The spray bar 40 is equipped with multiple nozzles and / or spray holes to supply cleaning fluid toward the wafer surface;

[0057] The control module is used to control the steps of the wafer cleaning method described above. The spray flow rate of the spray bar segment with the same spray direction as the wafer rotation direction needs to be greater than that of the spray bar segment with the opposite spray direction to the wafer rotation direction. This is to ensure that the cleaning fluid is distributed approximately evenly on the wafer surface, effectively removes particles from the wafer surface, and ensures a good cleaning effect.

[0058] Since particulate matter is easily left in the center of the wafer, in order to enhance the cleaning effect in the center of the wafer, the orifice diameter and spacing of the nozzle 40a and / or spray hole 40b at the center of the spray bar 40 can be adjusted.

[0059] Figure 4A In this embodiment, the diameter of the nozzle 40b at the middle position of the spray bar 40 is larger than the diameter of the nozzle 40b at the end position of the spray bar 40. As a variation of this embodiment, the spacing between adjacent nozzles 40b at the middle position of the spray bar 40 is smaller than the spacing between adjacent nozzles 40b at the end position of the spray bar 40, such as... Figure 4B As shown, this method focuses on removing residual particles at the center of the wafer to ensure the overall cleaning effect of the wafer.

[0060] Figure 5A This is a schematic diagram of another embodiment of the nozzles 40b configured on the spray bar 40. The nozzles 40b are not arranged along the axial direction of the spray bar 40, but rather along a quadratic curve. Specifically, the nozzles 40b are symmetrically distributed along the length of the spray bar 40. The nozzles 40b at the middle position of the spray bar 40 are arranged along a quadratic curve, which is a curve with the midpoint of the spray bar 40 as its axis of symmetry. This shortens the distance between the nozzles 40b at the middle position of the spray bar 40 and the wafer surface, enhancing the cleaning effect at the wafer center and avoiding particulate residue.

[0061] Figure 5A In the process, the diameter of the nozzle 40b in the middle of the spray bar 40 is larger than that in other positions, so as to enhance the supply of cleaning fluid to the center of the wafer and ensure the overall cleaning effect of the wafer.

[0062] As another embodiment of the present invention, due to the different rotation directions of the wafer, the motion state of the cleaning fluid sprayed onto the wafer surface by the spray bar 40 varies. Therefore, the spray holes 40b on the spray bar 40 can be asymmetrically arranged. Specifically, the spacing between the spray holes 40b corresponding to the spray bar segments with the same rotation direction as the wafer is smaller than the spacing between the spray holes 40b corresponding to the spray bar segments with the opposite rotation direction, such as... Figure 5B As shown.

[0063] It is understandable that the spacing between adjacent nozzles 40b on one section of the spray bar 40 is greater than the spacing between adjacent nozzles 40b on the other section of the spray bar 40, allowing for effective utilization of the cleaning fluid sprayed by the spray bar 40. Based on the above scheme, the nozzles 40b can also have the following variations:

[0064] The diameter of the nozzle 40b at the middle position of the spray bar 40 can be larger than the diameter of the nozzles 40b at other positions, such as... Figure 6 As shown in (a), this enhances the cleaning effect at the center of the wafer;

[0065] The spacing between adjacent nozzles 40b at the middle position of the spray bar 40 is smaller than the spacing between adjacent nozzles 40b at the end position of the spray bar 40, such as... Figure 6 As shown in (b), this is to enhance the cleaning effect at the center of the wafer.

[0066] It is understandable that the orifice diameters of the nozzles 40b on the spray bar 40 can be set to be consistent, and the spacing between the nozzles 40b can be set to be equal, such as... Figure 6 (c) and Figure 7 As shown in (a), the distance between the nozzle 40b and the wafer surface is adjusted by the curvature of the quadratic curve to enhance the cleaning effect at the center of the wafer.

[0067] In some embodiments, the diameter of the nozzle 40b at the middle of the spray bar 40 and at the end parallel to the wafer rotation direction can be larger than the diameter of the nozzle 40b at other locations, such as... Figure 7 As shown in (b), this enhances the cleaning effect at the center and edge of the wafer.

[0068] The diameter of the nozzle 40b at the end of the spray bar 40 that is in the same direction as the wafer rotation can be gradually increased. The distance between the nozzle 40b and the wafer surface can be adjusted by using the curvature of the quadratic curve. Figure 7 As shown in (c), this enhances the cleaning effect at the wafer edges and center.

[0069] Furthermore, the present invention also discloses a cleaning control system, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the wafer cleaning method described above. For example, the cleaning control system may also include input / output devices, network access devices, buses, etc.

[0070] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0071] The memory can be an internal storage unit of the control device, such as a hard drive or RAM. Alternatively, it can be an external storage device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units. The memory is used to store the computer program and other programs and data required by the control device. It can also be used to temporarily store data that has been output or will be output.

[0072] In addition, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the wafer cleaning method described above.

[0073] The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wafer cleaning method, comprising: S1, The wafer to be cleaned is placed in the cleaning device, and the support vertically supports the wafer; S2, The cleaning brush moves towards the wafer to abut against the wafer surface, and the support rotates the wafer around its axis; S3, The spray bar in the cleaning device sprays cleaning fluid towards the wafer surface, and the cleaning brush absorbs the cleaning fluid on the wafer surface and rotates to remove particles from the wafer surface; wherein, when the nozzle and / or orifice of the spray bar sprays cleaning fluid, the spray flow rate of the spray bar section with the spray direction in the same direction as the wafer's rotation is greater than the spray flow rate of the spray bar section with the spray direction opposite to the wafer's rotation; the cleaning fluid originates from the middle position of the spray bar. The material is supplied and sprayed through nozzles and / or orifices located on both sides of the supply position; the orifices are asymmetrically distributed along the length of the spray bar, and the spacing between the orifices corresponding to the spray bar segments with the same spray direction as the wafer rotation direction is smaller than the spacing between the orifices corresponding to the spray bar segments with the opposite spray direction to the wafer rotation direction; the spacing between the orifices at the middle position of the spray bar is smaller than the spacing between the orifices at other positions of the spray bar; the orifice diameter gradually increases from the middle position of the spray bar towards the spray bar segments with the same rotation direction as the wafer; the orifices at the middle position of the spray bar are distributed along a quadratic curve, the quadratic curve being a curve with the midpoint of the spray bar as the axis of symmetry.

2. The wafer cleaning method as described in claim 1, characterized in that, The nozzle is equipped with an independent supply line that can move along the length of the spray bar to adjust the spray position of the cleaning fluid.

3. A cleaning control system, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the wafer cleaning method as described in any one of claims 1 or 2.

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