Wafer cleaning device

Abstract

The invention discloses a wafer cleaning device which comprises a box body internally provided with an overflow groove. The supporting assembly is arranged in the overflow groove so as to support and drive the wafer to rotate; the liquid spraying assembly is arranged in the overflow groove so as to spray liquid towards the bottom of the overflow groove; the overflow groove comprises a groove main body, a rectification part and a contraction part, the groove main body is a rectangular groove body, and the rectification part and the contraction part are sequentially arranged above the groove main body; a vibration plate is arranged between the rectification part and the contraction part, is obliquely arranged and emits high-frequency sound waves towards the wafer; the rectification part is a rectangular groove body, and the internal width of the rectification part is smaller than that of the groove main body; and the fluid moving upwards through the rectifying part can discharge pollutants stripped by the high-frequency sound waves from the top of the overflow groove.

Description

[0001] This application is a divisional application of the invention patent application with application number 2023107876114 filed on June 30, 2023. Technical Field

[0002] The present invention belongs to the technical field of wafer post-processing, and in particular relates to a wafer cleaning device. Background Art

[0003] The integrated circuit industry is the core of the information technology industry and plays a key role in promoting the transformation and upgrading of the manufacturing industry towards digitalization and intelligentization. Chips are the carriers of integrated circuits. Chip manufacturing involves a series of processes including integrated circuit design, wafer fabrication, wafer processing, electrical measurement, cutting, packaging, and testing.

[0004] Chemical Mechanical Polishing (CMP), one of the five core processes in wafer manufacturing, is an ultra-precision surface finishing technology that achieves global flatness. Wafers that have undergone CMP require post-processing, including cleaning and drying, to prevent contamination of semiconductor devices by trace ions and metal particles, thereby ensuring their performance and yield.

[0005] There are several wafer cleaning methods: roller brush cleaning, megasonic cleaning, etc. Among them, megasonic cleaning is one of the commonly used cleaning methods. Figure 1 This is a schematic diagram of a conventional megasonic cleaning device, comprising a cleaning tank 10'. A megasonic vibration plate 20' is positioned at the bottom of the tank 10', with the wafer W to be cleaned positioned directly above the plate 20'. The plate 20' emits high-frequency sound waves to remove contaminants such as tiny particles from the surface of the wafer W. Furthermore, a nozzle 30' is positioned at the bottom of the tank 10'. The nozzle 30' has multiple nozzles that spray cleaning fluid obliquely upward, overflowing from the top of the tank 10' to remove the removed contaminants.

[0006] In the prior art, the megasonic vibration plate 20' is placed at the bottom of the cleaning tank 10', which is far away from the wafer to be cleaned. The high-frequency sound waves emitted by the megasonic vibration plate 20' will be attenuated in the fluid. When the high-frequency sound waves act on the bottom of the wafer, their intensity will be attenuated to a certain extent, that is, Figure 1 In the figure, the area corresponding to the vertical distance H between the megasonic vibration plate 20 ′ and the bottom end of the wafer W is the ineffective attenuation area of the acoustic wave; Figure 1 The dotted line in the figure represents the curve of sound wave attenuation, where the horizontal axis represents the sound wave intensity and the vertical axis represents the radial position of the wafer when the sound wave reaches the top of the wafer. When the high-frequency sound wave reaches the top of the wafer, its intensity may not be enough to effectively remove the contaminants, which will cause the cleaning effect of the top of the wafer to deteriorate and fail to meet the process requirements.

[0007] The existing cleaning tank 10' is usually a rectangular tank, in which the sprayed cleaning liquid has a large backflow and turbulence, such as Figure 2 As shown, this will cause the contaminants that fall off the wafer surface to not be discharged in time, causing secondary contamination. In addition, the rectangular tank is large in size, which will consume a large amount of cleaning fluid and increase the cost of wafer cleaning. Summary of the Invention

[0008] An embodiment of the present invention provides a wafer cleaning device, which aims to solve at least one of the technical problems existing in the prior art.

[0009] An embodiment of the present invention provides a wafer cleaning device, characterized by comprising:

[0010] The box body is provided with an overflow tank inside;

[0011] A support assembly is provided in the overflow tank to support and drive the wafer to rotate;

[0012] a liquid spraying assembly, disposed in the overflow trough to spray liquid toward the bottom of the overflow trough;

[0013] The overflow trough includes a trough body, a rectifying portion and a contraction portion, wherein the trough body is a rectangular trough body, and the rectifying portion and the contraction portion are sequentially arranged above the trough body;

[0014] A vibration plate is provided between the rectifying portion and the contracting portion, and is tilted to emit high-frequency sound waves toward the wafer;

[0015] The rectifying part is a rectangular trough body, the inner width of which is smaller than the inner width of the trough body; the fluid moving upward through the rectifying part can discharge the pollutants stripped by the high-frequency sound waves from the top of the overflow trough.

[0016] In one embodiment, the vibration plate is arranged on the side of the vertical center line of the overflow trough, and is arranged to extend upward and outward.

[0017] In one embodiment, the angle between the vibration plate and the horizontal plane is 2-30°.

[0018] In one embodiment, the contraction portion is a trough body with a trapezoidal longitudinal section, and its side panels are arranged to extend upward and inwardly.

[0019] In one embodiment, the angle between the side plate of the contraction portion and the vertical center line of the overflow trough is 1-15°.

[0020] In one embodiment, the support assembly and the liquid spray assembly are arranged in the tank body, and the liquid spray assembly is located below the support assembly.

[0021] In one embodiment, the inner width of the rectifying portion is 1 / 3-2 / 3 of the inner width of the slot body.

[0022] In one embodiment, the transverse dimension of the constriction is smaller than or equal to the transverse dimension of the slot body.

[0023] In one embodiment, the vibration plate is at least partially located below the center axis of the wafer to be cleaned.

[0024] In one embodiment, the width of the vibration plate is 10-50 mm.

[0025] The beneficial effects of the present invention include:

[0026] a. The overflow tank of the wafer cleaning device is equipped with a rectifying section to rectify the fluid sprayed by the liquid spraying assembly, reduce or avoid backflow or turbulence of the fluid in the overflow tank, and prevent the particles removed by megasonic stripping from reattaching to the wafer surface;

[0027] b. The overflow trough of the wafer cleaning device is provided with a contraction portion to control the space between the contraction portion and the wafer. Sound waves can be reflected in the above space to maintain the sound pressure intensity of the overflow trough; at the same time, the contraction portion of the overflow trough can reduce the size of the overflow trough chamber and reduce the amount of cleaning liquid sprayed by the spray assembly, which is beneficial to controlling the cost of wafer cleaning.

[0028] c. Place the vibration plate to the side of the wafer to be cleaned to reduce the distance between the vibration plate and the wafer, reduce the attenuation of high-frequency sound waves, and ensure the effectiveness of megasonic cleaning; place the vibration plate below the central axis of the wafer so that the high-frequency sound waves emitted by the vibration plate can cover the upper half of the wafer; the support assembly can drive the wafer to rotate around the central axis to cover all areas of the wafer, achieving megasonic cleaning of the wafer;

[0029] d. The liquid spray assembly for overflow discharge is arranged at the lower part of the overflow trough, away from the vibration plate to reduce or avoid the interference of the sprayed cleaning liquid on the high-frequency sound waves; the liquid spray assembly sprays the cleaning liquid in an inclined downward staggered manner to control the degree of turbulence of the cleaning liquid in the overflow trough and ensure that the direction of the rectified fluid is in the vertical direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, which are only exemplary and do not limit the scope of protection of the present invention, wherein:

[0031] Figure 1 It is a schematic diagram of a megasonic cleaning device in the prior art;

[0032] Figure 2 yes Figure 1 Corresponding flow field diagram inside the megasonic cleaning device;

[0033] Figure 3 is a schematic diagram of a circular cleaning device provided by one embodiment of the present invention;

[0034] Figure 4 yes Figure 3 Schematic diagram of the corresponding overflow trough;

[0035] Figure 5 is a graph of sound pressure intensity in an overflow tank provided by one embodiment of the present invention;

[0036] Figure 6 This is a flow field diagram inside a circular cleaning device provided by one embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of a circular cleaning device provided by another embodiment of the present invention;

[0038] Figure 8 yes Figure 7 Schematic diagram of the corresponding overflow trough;

[0039] Figure 9 yes Figure 8 A graph showing the sound pressure intensity of the overflow tank of the wafer cleaning device;

[0040] Figure 10 It is a sound pressure intensity curve corresponding to the megasonic cleaning device in the prior art. DETAILED DESCRIPTION

[0041] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments and the accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0042] The drawings in this specification are schematic diagrams that assist in illustrating the concepts of the present invention and schematically illustrate the shapes of the various components and their interrelationships. It should be understood that in order to clearly illustrate the structures of the various components of the embodiments of the present invention, the drawings are not drawn to the same scale, and the same reference numerals are used to represent the same parts in the drawings.

[0043] In the present invention, wafer (W) is also called substrate (Substrate), and its meaning and actual function are equivalent. The term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. can refer to different or the same objects, and are only used to distinguish the objects referred to, and do not imply a specific spatial order, temporal order, order of importance, etc. of the objects referred to. In some embodiments, values, processes, selected items, determined items, equipment, devices, means, components, assemblies, etc. are referred to as "best", "lowest", "highest", "minimum", "maximum", etc. It should be understood that such descriptions are intended to indicate that a selection can be made from a number of available functional options, and that such a selection does not need to be better, lower, higher, smaller, larger, or otherwise preferred than other options in other aspects or all aspects.

[0044] Figure 3 FIG. 1 is a schematic diagram of a wafer cleaning apparatus 100 provided in one embodiment of the present invention, which includes:

[0045] The box 10 is a rectangular trough structure, and components for wafer cleaning are disposed inside the box 10. A switch door (not shown) is disposed on the top of the box 10, through which an external robot can place wafers in or out of the box 10. An overflow trough 40 is disposed inside the box 10. The vertical height of the overflow trough 40 is less than the height of the box 10, so that the liquid in the overflow trough 40 can overflow into the interior of the box 10 through its top.

[0046] The support assembly 20 is disposed in the overflow tank 40 to vertically support the wafer W to be cleaned; specifically, the support assembly 20 includes at least one pair of rollers ( Figure 2 (shown), the roller is arranged at the lower part of the overflow trough 40, so that the groove of the roller can be clamped along the edge of the wafer to be cleaned, so that the wafer W is in a vertical state; at the same time, the end of the roller is also configured with a drive motor (not shown), which can drive the roller to rotate around the axis, so as to drive the wafer to rotate under the action of the friction between the roller groove and the wafer; in some embodiments, the support assembly 20 further includes a tachometer wheel, which is arranged between the pair of rollers, and the three are clamped to the outer edge of the wafer, and the tachometer wheel is used to monitor the running status of the wafer;

[0047] The vibration plate 30 is part of the overflow trough 40 or is located on the inner wall of the overflow trough 40. Also known as a transducer, the vibration plate 30 is tilted in the housing 10 to provide high-frequency vibrations from the side. The high-frequency sound waves emitted by the vibration plate 30 act on the surface of the wafer to be cleaned, removing contaminants attached to the wafer surface. The transducer converts the electrical output of the power supply into a vibration output. The generated sound waves are transmitted through the fluid, and through the effects of cavitation and sonic flow, they remove particles attached to the wafer surface.

[0048] The liquid spray assembly 50 can spray fluid toward the overflow trough 40 to discharge pollutants such as particulate matter stripped off by the high-frequency sound waves from the top of the overflow trough 40. Specifically, the top of the overflow trough 40 is open, and the fluid sprayed by the liquid spray assembly 50 can fill the overflow trough 40 and overflow from the top opening of the overflow trough 40, so as to discharge the stripped pollutants between the housing 10 and the overflow trough 40.

[0049] In the present invention, the vibration plate 30 is arranged on the side of the wafer to be cleaned, and the distance between it and the wafer W is relatively close to reduce the attenuation of the high-frequency sound waves emitted by the vibration plate 30, ensure the effects of cavitation and sonic flow, and fully peel off the particles from the surface of the wafer to achieve a good megasonic cleaning effect.

[0050] Specifically, the overflow trough 40 is vertically disposed within the housing 10, and the wafer W to be cleaned is disposed along the vertical centerline of the overflow trough 40. The vibration plate 30, which provides high-frequency sound waves for wafer cleaning, is disposed lateral to the vertical centerline of the overflow trough 40. Specifically, the vibration plate 30 is disposed lateral to the wafer W to be cleaned, providing high-frequency sound waves from the side of the wafer, generating cavitation and sonic flow effects within the overflow trough 40, stripping away particles adhering to the wafer surface and thereby fully cleaning the wafer surface.

[0051] like Figure 3 In the embodiment, the vibration plate 30 and other plates together form an overflow trough 40, and the support assembly 20 and the liquid spray assembly 50 are disposed at the bottom of the overflow trough 40. That is, the wafer W to be cleaned is vertically disposed in the overflow trough 40. This arrangement helps to reduce the space required for megasonic cleaning of the wafer W, allowing high-frequency sound waves to effectively act on the wafer surface.

[0052] Figure 4 It is a schematic diagram of an overflow trough 40 provided in one embodiment of the present invention. The overflow trough 40 includes a trough body 41, a rectifying portion 42 and a contraction portion 43, wherein the trough body 41, the rectifying portion 42 and the contraction portion 43 are arranged in sequence along the vertical direction from bottom to top to form a trough structure with an open top.

[0053] Furthermore, the tank body 41 is located at the bottom of the overflow tank 40 and has a rectangular structure in longitudinal section. The support assembly 20 is disposed inside the tank body 41 to vertically support the wafer to be cleaned.

[0054] Furthermore, compared with other parts of the overflow trough 40, the internal width of the trough body 41 is larger to provide sufficient space for the placement of the support assembly 20. In the present invention, the internal width of the trough body 41, the rectifying portion 42 and the contraction portion 43 refers to the lateral width between the inner side walls of the trough body.

[0055] The rectifying portion 42 is disposed at the upper end of the tank body 41. Specifically, the rectifying portion 42 is a tank body structure, which is vertically disposed above the tank body 41.

[0056] Furthermore, the inner width of the rectifying portion 42 is suddenly reduced. This configuration can regulate the flow direction of the fluid, avoid fluid disturbance inside the tank body 41, and prevent particles peeled from the wafer from reattaching to the wafer surface, thereby ensuring the wafer cleaning effect.

[0057] In some embodiments, the internal width of the rectifying portion 42 is 1 / 3-2 / 3 the internal width of the trough body 41 to achieve a good rectifying effect. Specifically, the liquid spraying assembly 50 sprays fluid toward the bottom surface of the trough body 41, where the fluid repeatedly splashes within the trough body 41, forming a turbulent flow. This chaotic fluid is rectified by the rectifying portion 42, which has a smaller lateral width, and becomes smooth. The smooth fluid is then transported upward through the rectifying portion 42 to flush particles peeled from the wafer surface and discharge the particles through the top opening of the overflow trough 40.

[0058] Preferably, the internal width of the rectifying portion 42 is 1 / 3 to 1 / 2 of the internal width of the tank body 41, so that the fluid sprayed by the liquid spraying assembly 50 becomes smooth after being rectified by the rectifying portion 42. The rectified fluid can be transmitted upward in a generally vertical direction, thereby reducing backflow and turbulence, preventing the peeled particles from reattaching to the wafer surface and causing secondary contamination, and achieving a good cleaning effect.

[0059] Furthermore, the vibration plate 30 is arranged to extend outwardly along the upper end of the rectifying portion 42, as shown in FIG. Figure 4 Specifically, the vibration plate 30 extends upward and outward from the end of the rectifying portion 42, so that the high-frequency sound waves generated by the vibration plate 30 can be transmitted obliquely to the wafer surface, thereby utilizing cavitation and sonic flow effects to remove particles from the wafer surface. In the present invention, the outward inclination of the components of the overflow trough 40 refers to inclination toward the outside of the overflow trough 40, and the inward inclination of the components of the overflow trough 40 refers to inclination toward the vertical centerline of the overflow trough 40.

[0060] Furthermore, the contraction portion 43 is a trough body with a trapezoidal longitudinal section, and at least one side plate of the contraction portion 43 extends inwardly and obliquely along the upper end of the vibration plate 30, that is, the contraction portion 43 extends upward and inward. In the present invention, the side plate of the contraction portion 43 refers to the plate member located to the side of the vertical centerline of the overflow trough 40.

[0061] The internal width of the constricted portion 43 gradually decreases from bottom to top, forming a constricted space. The high-frequency sound waves generated by the vibration plate 30 are transmitted through the constricted space between the constricted portion 43 and the wafer W, concentrating toward the upper portion of the wafer W. Simultaneously, the high-frequency sound waves generated by the vibration plate 30 are reflected in the constricted space toward the wafer surface, enhancing the sound pressure intensity of the overflow trough 40 and improving the wafer cleaning effect.

[0062] Figure 4 In the figure, the dotted line represents the transmission route of the high-frequency sound waves emitted by the vibration plate 30 between the inner wall of the contraction portion 43 and the wafer W. It can be seen that the reflection of the high-frequency sound waves can enhance the efficiency of megasonic cleaning and improve the effect of wafer cleaning.

[0063] In some embodiments, the angle between the contraction portion 43 and the vertical center line of the overflow groove 40 is 1-15°; preferably, the angle between the contraction portion 43 and the vertical center line of the overflow groove 40 is 1-10°, so as to reasonably control the space between the inner wall of the contraction portion 43 and the wafer W to ensure the transmission and reflection effect of high-frequency sound waves.

[0064] To ensure that the inner wall of the contraction 43 can effectively reflect sound waves, the roughness of the inner wall of the contraction 43 should be controlled within Ra0.1. Furthermore, the contraction 43 should be made of a hydrophobic material to prevent particles from adhering to the inner wall of the contraction 43. If a large amount of particles adhere to the inner wall of the contraction 43, the sound waves will be diffusely reflected, which is not conducive to maintaining the sound pressure intensity of the overflow trough 40 and is not conducive to achieving a good megasonic cleaning effect.

[0065] In some embodiments, the overflow trough 40 includes the main body 41, the rectifying portion 42, and the contracting portion 43 made of polytetrafluoroethylene. Polytetrafluoroethylene has high lubricity and non-adhesive properties, preventing particles removed by megasonic cleaning from adhering to the inner wall of the overflow trough 40 and affecting the reflection of sound waves. This helps control the sound pressure intensity of the overflow trough 40 and ensure a good cleaning effect.

[0066] Figure 5 The curve of the sound pressure intensity in the overflow tank 40 is shown. Since the contraction portion 43 of the overflow tank 40 reflects sound waves, the sound pressure intensity in this area increases, which helps to enhance the cavitation and sonic flow effects of high-frequency sound waves, thereby fully removing particles from the wafer surface and achieving surface cleaning.

[0067] During megasonic cleaning of the wafer, the wafer W rotates around its central axis so that the high-frequency sound waves emitted by the vibration plate 30 can fully cover the wafer surface, thereby cleaning every area of the wafer and avoiding blind spots in the megasonic cleaning that affect the wafer cleaning effect.

[0068] In the present invention, the vibration plate 30 is disposed toward the surface to be cleaned of the wafer W to emit high-frequency sound waves toward the surface to be cleaned. Figure 4In the embodiment, the vibration plate 30 is positioned on one side of the wafer W to be cleaned, that is, facing the front of the wafer, to clean the wafer surface through megasonic cleaning. In the present invention, the front side of the wafer refers to the side where electronic devices are arranged; the back side of the wafer refers to the side where electronic devices are not arranged, that is, the side opposite the front side of the wafer.

[0069] As one aspect of this embodiment, the vibration plate 30 is positioned at an angle of 2-30° with respect to the horizontal plane; preferably, the angle is 5-15°. This allows the high-frequency sound waves emitted by the vibration plate 30 to be transmitted upward at an angle, effectively removing particles from the wafer surface. During megasonic cleaning, the wafer rotates about its central axis, driven by the support assembly 20, allowing the high-frequency sound waves emitted by the vibration plate 30 to fully impact the wafer surface.

[0070] In the present invention, the vibration plate 30 is tilted, and the component of the sound wave it emits can be perpendicular to the wafer surface, which is beneficial to improving the removal rate and ensuring the cleaning effect of the wafer; at the same time, the vibration plate 30 is tilted, which is beneficial to reducing the interference of bubbles during the cleaning process and enhancing the vibration effect on the particles.

[0071] As an embodiment of the present invention, the width of the vibration plate 30 is 10-50 mm. Here, the width of the vibration plate 30 refers to the size corresponding to the longitudinal section of the vibration plate 30, that is, Figure 4 The distance between the upper end of the rectifying portion 42 and the lower end of the contraction portion 43. The width of the vibration plate 30 is set within a certain range to ensure that the high-frequency sound waves emitted by the vibration plate 30 cover the radial direction of the wafer as much as possible, thereby ensuring the cleaning effect of the wafer.

[0072] It is understood that the width of the vibration plate 30 should not be too large in order to control the size of the overflow tank 40, reduce the amount of cleaning fluid used, and control the wafer cleaning cost. Preferably, the width of the vibration plate 30 is 15-30 mm.

[0073] In the present invention, the vibration plate 30 is extended in the horizontal direction ( Figure 7 As shown), its lateral length should be greater than the diameter of the wafer, or the lateral length of the vibration plate 30 should be greater than the chord length of the wafer (that is, the length corresponding to the horizontal projection of the vibration plate 30 on the wafer), so that the ultrasonic waves generated by the vibration plate 30 can cover the surface of the wafer.

[0074] As one embodiment of the present invention, the vibration plate 30 is made of an electroacoustic material. Specifically, the vibration plate 30 is made of a piezoelectric material to convert electrical energy into vibrations and form high-frequency sound waves. Preferably, the vibration plate 30 is made of a lead zirconate titanate (PZT) piezoelectric ceramic, a barium titanate (BaTiO3) piezoelectric ceramic, or the like.

[0075] In one embodiment of the present invention, at least a portion of the vibration plate 30 is positioned below the central axis of the wafer to be cleaned to ensure that the high-frequency sound waves emitted by the vibration plate 30 are transmitted radially. During the megasonic cleaning process, the wafer rotates about its central axis, allowing the high-frequency sound waves to fully cover all areas of the wafer.

[0076] Figure 4 In the embodiment shown, the horizontal spacing between the rectifying portion 42 and the vertical center line of the overflow trough 40 is smaller than the horizontal spacing between the contraction portion 43 and the vertical center line of the overflow trough 40. Since the contraction portion 43 is tilted upward and inward from the upper end of the self-vibration plate 30, the horizontal spacing between the upper end of the contraction portion 43 and the vertical center line of the overflow trough 40 is minimized. In this embodiment, the horizontal spacing between the rectifying portion 42 and the vertical center line of the overflow trough 40 is smaller than the minimum horizontal spacing between the contraction portion 43 and the vertical center line of the overflow trough 40. In the present invention, the horizontal spacing between the rectifying portion 42 and the vertical center line of the overflow trough 40 refers to the horizontal distance between the inner side wall of the rectifying portion 42 and the vertical center line, and the horizontal spacing between the contraction portion 43 and the vertical center line of the overflow trough 40 refers to the horizontal distance between the inner side wall of the contraction portion 43 and the vertical center line.

[0077] As one aspect of this embodiment, the horizontal spacing between the rectifying portion 42 and the vertical centerline of the overflow trough 40 is 2-15 mm, and the horizontal spacing between the contracting portion 43 and the vertical centerline of the overflow trough 40 is 5-25 mm. This arrangement facilitates controlling the internal space of the overflow trough 40, improving the sound pressure intensity within the overflow trough 40, meeting the requirements of wafer megasonic cleaning, and achieving excellent cleaning results.

[0078] Figure 4 In the embodiment, the side panels of the contraction portion 43 opposite to the wafer cleaning surface are tilted, while the side panels of the contraction portion 43 opposite to the wafer cleaning surface are vertically arranged to reduce the internal space of the overflow trough 40 and control the sound pressure intensity of the overflow trough 40.

[0079] In addition, since the overflow tank 40 is equipped with the rectifying portion 42 and the contracting portion 43, its internal volume is reduced, which helps to reduce the amount of cleaning liquid used and control the cost of wafer cleaning. That is, the liquid spraying assembly 50 disposed at the bottom of the overflow tank 40 only needs to spray a small amount of cleaning liquid to fill the overflow tank 40, thereby cleaning the particles in the overflow tank 40 by overflow. In some embodiments, Figure 3 The wafer cleaning apparatus shown can save 5-20L of cleaning fluid per hour, thereby controlling wafer post-processing costs. During wafer cleaning, cleaning fluid needs to be regularly supplied to the interior of the overflow tank 40. Since the overflow tank 40 provided by the present invention is relatively small in volume, the amount of cleaning fluid used can be reduced.

[0080] In order to ensure a good overflow effect and clean the particulate matter in the overflow trough 40 in time, the spray assembly 50 is arranged below the vibration plate 30, so that the fluid sprayed by the spray assembly 50 is away from the vibration plate 30, avoiding the influence of the turbulent fluid on the high-frequency sound waves emitted by the vibration plate 30, and avoiding the mutual influence between megasonic cleaning and overflow discharge.

[0081] Furthermore, the support assembly 20 is located in the tank body 41 of the overflow tank 40 , and the liquid spraying assembly 50 is located below the support assembly 20 . The cleaning liquid sprayed by the liquid spraying assembly 50 is directed toward the bottom of the tank body 41 .

[0082] In the present invention, the spray assembly 50 sprays fluid in a downwardly slanted direction, spraying the fluid toward the bottom surface of the tank body 41. This downward spray direction keeps the fluid as far away from the wafer being megasonic cleaned as possible, minimizing the impact of the sprayed fluid on the megasonic cleaning process. This is because the fluid sprayed by the spray assembly 50 primarily overflows to flush away debonded particles, rather than cleaning particles from the wafer surface through a rinsing action. Setting the spray assembly 50's downwardly slanted spray direction helps ensure effective megasonic cleaning.

[0083] Furthermore, the liquid spray assembly 50 includes at least one pair of nozzles disposed within the main body 41 of the overflow trough 40 and spraying cleaning fluid toward the interior of the overflow trough 40. The nozzles are equipped with multiple liquid spray ports, spaced apart along the length of the nozzles. To control the degree of splashing of the fluid sprayed by the liquid spray assembly 50, adjacent liquid spray ports are spaced apart and staggered to reduce the impact and / or crossover of the fluid within the main body 41, minimizing the degree of fluid disturbance and ensuring, to a certain extent, a relatively smooth flow of the fluid passing through the rectifying portion 42.

[0084] It is understood that the liquid spray port can be a nozzle, or a nozzle can be installed at the position of the liquid spray port to supply the cleaning liquid to the overflow tank 40. In some embodiments, the nozzle installed at the liquid spray port can be a cylindrical nozzle or a conical nozzle so that the sprayed fluid is dispersed in the chamber of the tank body 41.

[0085] Figure 6 This diagram shows the flow field inside a circular cleaning device according to one embodiment of the present invention, specifically illustrating the flow of cleaning fluid within overflow trough 40. After being rectified by rectifying section 42, the cleaning fluid within trough body 41 flows generally vertically upward, effectively reducing disturbances and backflow within overflow trough 40.

[0086] Specifically, the liquid spraying component 50 ( Figure 4 The cleaning liquid sprayed toward the overflow trough 40 (as shown) flows in a vertical direction to push the particles removed by the megasonic cleaning to move upward, and finally flows through the upper edge of the overflow trough 40 to between the overflow trough 40 and the box body 10.

[0087] Figure 7 is a schematic diagram of a wafer cleaning device 100 provided by another embodiment of the present invention, Figure 3 Compared with the illustrated embodiment, the structure of the overflow groove 40 and the number of the vibration plates 30 are different.

[0088] Figure 8 yes Figure 7 In the schematic diagram of the overflow tank 40 in the embodiment shown, the wafer cleaning apparatus 100 is equipped with a pair of vibration plates 30, which are symmetrically arranged on both sides of the overflow tank 40. That is, the pair of vibration plates 30 can clean the front and back sides of the wafer W respectively, achieving double-sided cleaning of the wafer.

[0089] The vibration plate 30 is arranged between the rectification part 42 and the contraction part 43, and the vibration plate 30 is arranged to be tilted upward and outward from the upper end of the rectification part 42, so that the high-frequency sound waves emitted by the vibration plate 30 can propagate toward the surface of the wafer, so as to peel off the particles on the surface of the wafer under the action of cavitation and acoustic wave flow effects.

[0090] and Figure 4 Compared to the structure of the overflow trough 40 shown in FIG, the contraction portion 43 adopts a symmetrical structure. That is, a contraction structure is formed at the upper end of the overflow trough 40. When the fluid in the overflow trough 40 passes through the contraction structure, its flow rate is appropriately increased, and the cleaning liquid containing particulate matter can quickly overflow from the top of the overflow trough 40.

[0091] It is understandable that when one side of the wafer requires megasonic cleaning, Figure 8 The symmetrical structure of the overflow trough 40 shown ensures rapid overflow of the cleaning liquid, discharging particulate matter removed by megasonic cleaning through overflow discharge between the overflow trough 40 and the housing 10. That is, the portion above the rectifying portion 42 also adopts a symmetrical structure relative to the vertical centerline. Depending on actual needs, one or two vibration plates 30 are provided between the rectifying portion 42 and the contracting portion 43.

[0092] It should be noted that the tilt angles and performance parameters of the vibration plates 30 provided on the front and back sides of the wafer may be different to adapt to the characteristics of the front and back sides of the wafer and enhance the effect of megasonic cleaning.

[0093] Figure 9 yes Figure 7 The sound pressure intensity curve of the overflow tank 40 of the wafer cleaning device 100 is shown, wherein the horizontal axis is the vertical position of the wafer. Specifically, the horizontal axis defines the position of the wafer with the bottom edge of the wafer as the zero point; the vertical axis is the sound pressure at the corresponding position of the overflow tank 40.

[0094] Figure 7 In the embodiment, the vibration plate 30 is set at a position below the center axis of the wafer, that is, the vibration plate 30 is set within the coordinate range of 100mm-150mm. Figure 9 It can be seen that the intensity of the high-frequency sound waves emitted by the vibration plate 30 has not been significantly attenuated, and the overall sound pressure of the overflow tank 40 is maintained within a relatively high range.

[0095] Figure 10 It is a megasonic cleaning device in the prior art ( Figure 1 The corresponding sound pressure intensity curve is shown in Figure 2. The meaning of its horizontal and vertical coordinates are the same as those of Figure 9 Because the megasonic vibration plate 20' is placed at the bottom of the cleaning tank 10', which is far away from the wafer to be cleaned, the high-frequency sound waves emitted by the megasonic vibration plate 20' are greatly attenuated in the fluid, resulting in a decrease in the sound pressure intensity in the overflow tank 40, which is not conducive to fully removing particles from the wafer surface.

[0096] The vibration plate 30 of the present invention is tilted and arranged in an area slightly below the center axis of the wafer, which effectively reduces the sound pressure attenuation, so that the overall sound pressure of the overflow groove 40 is higher, so as to fully peel off the particles on the surface of the wafer. The configured overflow groove 40 can rectify the internal fluid to avoid the back-sticking of particles, so as to obtain wafers with cleanliness that meets the requirements.

[0097] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses 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 any one or more embodiments or examples.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A wafer cleaning device, characterized in that: include: The box body is provided with an overflow tank inside; A support assembly is provided in the overflow tank to support and drive the wafer to rotate; a liquid spraying assembly, disposed in the overflow trough to spray liquid toward the bottom of the overflow trough; The overflow trough includes a trough body, a rectifying portion and a contraction portion, wherein the trough body is a rectangular trough body, and the rectifying portion and the contraction portion are sequentially arranged above the trough body; A vibration plate is provided between the rectifying portion and the contracting portion, and is tilted to emit high-frequency sound waves toward the wafer; The rectifying part is a rectangular trough, the inner width of which is smaller than the inner width of the trough body; the fluid moving upward through the rectifying part discharges the pollutants stripped by the high-frequency sound waves from the top of the overflow trough; The vibration plate is made of electroacoustic material to emit high-frequency sound waves toward the wafer.

2. The wafer cleaning device according to claim 1, wherein: The vibration plate is made of piezoelectric material to convert electrical energy into vibration and form high-frequency sound waves.

3. The wafer cleaning device according to claim 2, wherein: The vibration plate is made of lead zirconate titanate piezoelectric ceramics and barium titanate piezoelectric ceramics.

4. The wafer cleaning device according to claim 1, wherein: The vibration plate is arranged at a position below the center axis of the wafer.

5. The wafer cleaning device according to claim 1, wherein: The transverse length of the vibration plate is greater than the diameter of the wafer, so that the ultrasonic waves generated by the vibration plate cover the surface of the wafer.

6. The wafer cleaning device according to claim 1, wherein: The vibration plate is arranged on the side of the vertical center line of the overflow trough, and is arranged to extend upward and outward.

7. The wafer cleaning device according to claim 6, wherein: The number of the vibration plates is equal to the number of the overflow grooves, and they are arranged tilted toward the front side of the wafer. The front side of the wafer refers to the side where the electronic devices are arranged.

8. The wafer cleaning device according to claim 6, wherein: The angle between the vibration plate and the horizontal plane is 5-15 degrees, so that the high-frequency sound waves emitted by the vibration plate are transmitted upward at an angle to fully peel off the particles on the surface of the wafer.

9. The wafer cleaning device according to claim 6, wherein: The number of the vibration plates is a pair, which are symmetrically arranged on both sides of the overflow tank to clean the front and back sides of the wafer respectively, thereby achieving double-sided cleaning of the wafer.

10. The wafer cleaning device according to claim 1, wherein: The width of the vibration plate is 15-30 mm.

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