A wafer cleaning device

Abstract

The present invention discloses a wafer cleaning device, which includes a box body with an overflow tank arranged inside; a support assembly arranged in the overflow tank to support and drive the wafer to rotate; a liquid spraying assembly arranged in the overflow tank to spray liquid towards the bottom of the overflow tank; the overflow tank includes a tank main body, a rectifying part and a contracting part, the tank main body is a rectangular tank body, and the rectifying part and the contracting part are sequentially arranged above the tank main body; a vibration plate is arranged between the rectifying part and the contracting part, which is inclined and emits high-frequency sound waves towards the wafer; the rectifying part is a rectangular tank body, and its internal width is smaller than the internal width of the tank main body; the fluid moving upwards through the rectifying part can discharge the pollutants stripped by the high-frequency sound waves from the top of the overflow tank.

Description

Technical Field

[0001] The present invention belongs to the technical field of wafer post-processing, and more particularly, relates to a wafer cleaning device. Background Art

[0002] The integrated circuit industry is the core of the information technology industry and plays a key role in boosting the transformation and upgrading of the manufacturing industry towards digitalization and intelligentization. A chip is the carrier of an integrated circuit, and chip manufacturing involves integrated circuit design, wafer manufacturing, wafer processing, electrical measurement, cutting and packaging, and testing processes.

[0003] Chemical Mechanical Polishing (CMP) is one of the five core processes in wafer manufacturing and is an ultra-precision surface processing technology for global planarization. The wafers that have completed chemical mechanical polishing need to be subjected to post-processing such as cleaning and drying to avoid contamination of semiconductor devices by trace ions and metal particles and to ensure the performance and qualification rate of semiconductor devices.

[0004] The wafer cleaning methods include: brush rolling cleaning, megasonic cleaning, etc. Among them, megasonic cleaning is one of the commonly used cleaning methods. Figure 1 is a schematic diagram of a megasonic cleaning device in the prior art. The megasonic cleaning device includes a cleaning tank 10', a megasonic vibration plate 20' is arranged at the bottom of the cleaning tank 10', and the wafer W to be cleaned is arranged directly above the megasonic vibration plate 20'. The megasonic vibration plate 20' emits high-frequency sound waves to remove contaminants such as fine particles on the surface of the wafer W; at the same time, a spray pipe 30' is arranged at the bottom of the cleaning tank 10', the spray pipe 30' has a plurality of spray holes, and the spray holes spray the cleaning liquid obliquely upward and overflow from the top of the cleaning tank 10' to discharge the peeled contaminants to the outside of the cleaning tank 10'.

[0005] In the prior art, the megasonic vibration plate 20' is placed at the bottom of the cleaning tank 10', and it is far from the wafer to be cleaned. The high-frequency sound waves emitted by the megasonic vibration plate 20' will attenuate in the fluid. When the high-frequency sound waves act on the bottom of the wafer, their intensity will attenuate to a certain extent, that is Figure 1 in, the area corresponding to the vertical distance H between the megasonic vibration plate 20' and the bottom end of the wafer W is the acoustic wave ineffective attenuation area; Figure 1 uses a dotted line to represent the acoustic wave attenuation curve. Among them, the abscissa represents the acoustic wave intensity, and the ordinate represents the radial position where the acoustic wave reaches the wafer; when the high-frequency acoustic wave reaches the upper part of the wafer, its intensity may not be able to effectively peel off the contaminants, which will cause the cleaning effect of the upper part of the wafer to deteriorate and cannot meet the process requirements.

[0006] In the existing cleaning tank 10', it is usually a rectangular tank, and there are large backflows and turbulences in the sprayed cleaning liquid, as Figure 2As shown, this causes the contaminants that fall off the wafer surface to not be discharged in time, resulting in secondary pollution. In addition, the rectangular groove has a large volume, which consumes a large amount of cleaning liquid and increases the cost of wafer cleaning. Summary of the Invention

[0007] An embodiment of the present invention provides a wafer cleaning device, aiming to solve at least one of the technical problems existing in the prior art.

[0008] An embodiment of the present invention provides a wafer cleaning device, which is characterized by comprising:

[0009] A box body, inside which an overflow groove is provided;

[0010] A support assembly, which is arranged in the overflow groove to support and drive the wafer to rotate;

[0011] A liquid spraying assembly, which is arranged in the overflow groove to spray liquid towards the bottom of the overflow groove;

[0012] The overflow groove includes a groove main body, a rectifying part and a contracting part. The groove main body is a rectangular groove body, and the rectifying part and the contracting part are sequentially arranged above the groove main body;

[0013] A vibrating plate is arranged between the rectifying part and the contracting part, which is obliquely arranged and emits high-frequency sound waves towards the wafer;

[0014] The rectifying part is a rectangular groove body, and its internal width is smaller than the internal width of the groove main body; the fluid moving upward through the rectifying part can discharge the contaminants peeled off by the high-frequency sound waves from the top of the overflow groove.

[0015] In one embodiment, the vibrating plate is arranged on the side of the vertical center line of the overflow groove, and extends obliquely upward and outward.

[0016] In one embodiment, the included angle between the vibrating plate and the horizontal plane is 2 - 30°.

[0017] In one embodiment, the contracting part is a groove body with a trapezoidal longitudinal section, and its side plates extend obliquely upward and inward.

[0018] In one embodiment, the included angle between the side plate of the contracting part and the vertical center line of the overflow groove is 1 - 15°.

[0019] In one embodiment, the support assembly and the liquid spraying assembly are arranged in the groove main body, and the liquid spraying assembly is located below the support assembly.

[0020] In one embodiment, the internal width of the rectifying part is 1 / 3 - 2 / 3 of the internal width of the groove main body.

[0021] In one embodiment, the lateral dimension of the contraction part is less than or equal to the lateral dimension of the groove body.

[0022] In one embodiment, at least a part of the vibration plate is located below the central axis of the wafer to be cleaned.

[0023] In one embodiment, the width of the vibration plate is 10 - 50 mm.

[0024] The beneficial effects of the present invention include:

[0025] a. The overflow tank of the wafer cleaning device is provided with a rectifying part to rectify the fluid sprayed by the liquid spraying component, reducing or avoiding the backflow or turbulence of the fluid in the overflow tank, and preventing the particles peeled off by megasonic from adhering to the wafer surface again;

[0026] b. The overflow tank of the wafer cleaning device is provided with a contraction part to control the space between the contraction part and the wafer. Sound waves can be reflected in the above space to maintain the sound pressure intensity of the overflow tank; at the same time, the contraction part of the overflow tank can reduce the size of the overflow tank chamber, reducing the usage amount of the cleaning liquid sprayed by the liquid spraying component, which is beneficial to controlling the cost of wafer cleaning.

[0027] c. The vibration plate is arranged on the side of the wafer to be cleaned to reduce the distance between the vibration plate and the wafer, reducing the attenuation of high-frequency sound waves and ensuring the effect of megasonic cleaning; the vibration plate is arranged below the central axis of the wafer, so that the high-frequency sound waves emitted by the vibration plate can cover the upper half area of the wafer; the support component can drive the wafer to rotate around the central axis to cover all areas of the wafer, realizing the megasonic cleaning of the wafer;

[0028] d. The liquid spraying component for overflow discharge is arranged at the lower part of the overflow tank and is arranged away from the vibration plate to reduce or avoid the interference of the sprayed cleaning liquid on the high-frequency sound waves; the liquid spraying component sprays the cleaning liquid obliquely downward in a staggered manner to control the degree of disorder of the cleaning liquid in the overflow tank and ensure that the direction of the rectified fluid is along the vertical direction. Description of the Drawings

[0029] Through the detailed description in combination with the following drawings, the advantages of the present invention will become clearer and easier to understand. These drawings are only schematic and do not limit the protection scope of the present invention, where:

[0030] Figure 1 is a schematic diagram of a megasonic cleaning device in the prior art;

[0031] Figure 2 is Figure 1 the corresponding flow field diagram inside the megasonic cleaning device;

[0032] Figure 3 is a schematic diagram of a circular cleaning device provided by an embodiment of the present invention;

[0033] Figure 4 is Figure 3 a schematic diagram of the corresponding overflow tank in

[0034] Figure 5 a sound pressure intensity curve diagram in the overflow tank provided by an embodiment of the present invention;

[0035] Figure 6 a flow field diagram inside the circular cleaning device provided by an embodiment of the present invention;

[0036] Figure 7 a schematic diagram of a circular cleaning device provided by another embodiment of the present invention;

[0037] Figure 8 is Figure 7 a schematic diagram of the corresponding overflow tank in

[0038] Figure 9 is Figure 8 a sound pressure intensity curve diagram of the overflow tank of the wafer cleaning device shown;

[0039] Figure 10 a sound pressure intensity curve diagram corresponding to the megasonic cleaning device in the prior art. Specific Embodiments

[0040] The following combines specific embodiments and their accompanying drawings to detail the technical solutions of the present invention. The embodiments recorded herein are specific specific implementation manners of the present invention for explaining the concept of the present invention; these explanations are all explanatory and exemplary and should not be construed as limiting the implementation manner of the present invention and the protection scope of the present invention. Except for the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application, and these technical solutions include technical solutions that make any obvious substitutions and modifications to the embodiments recorded herein.

[0041] The drawings in this specification are schematic diagrams to assist in explaining the concept of the present invention, schematically showing the shapes of various parts and their mutual relationships. It should be understood that in order to clearly show the structures of the components in the embodiments of the present invention, the drawings are not drawn according to the same scale, and the same reference numerals are used to represent the same parts in the drawings.

[0042] In the present invention, a wafer (Wafer, W) is also referred to as a substrate, and their meanings and actual functions are equivalent. The term "comprising" and its like shall be construed as open inclusion, i.e., "including but not limited to". The term "based on" shall be construed as "at least partially based on". The term "an embodiment" or "the embodiment" shall be construed as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects, and are only used to distinguish the objects referred to, without implying a specific spatial order, temporal order, order of importance, etc. of the objects referred to. In some embodiments, values, processes, selected items, determined items, devices, apparatuses, means, components, assemblies, etc. are referred to as "optimal", "lowest", "highest", "minimum", "maximum", etc. It should be understood that such descriptions are intended to indicate that a selection can be made among many available functional options, and such a selection does not necessarily need to be better, lower, higher, smaller, larger or otherwise preferred in other aspects or all aspects than other options.

[0043] Figure 3 FIG. 4 is a schematic diagram of a wafer cleaning device 100 according to an embodiment of the present invention, which includes:

[0044] A box body 10, which has a rectangular groove structure. Components for wafer cleaning are provided inside the box body 10. A switch door (not shown) is configured on the top of the box body 10, and an external manipulator can place or take out the wafer into or from the box body 10 through the switch door. An overflow tank 40 is provided inside the box body 10, and the vertical height of the overflow tank 40 is less than the height of the box body 10, so that the liquid inside the overflow tank 40 can overflow inside the box body 10 through its top.

[0045] A support assembly 20, which is arranged in the overflow tank 40 to vertically support the wafer W to be cleaned. Specifically, the support assembly 20 includes at least a pair of rollers ( Figure 2 shown). The rollers are arranged at the lower part of the overflow tank 40, so that the grooves of the rollers can be clamped along the edge of the wafer to be cleaned, making the wafer W in a vertical state. At the same time, a driving motor (not shown) is configured at the end of the roller, and the driving motor can drive the roller to rotate around the axis, so as to drive the wafer to rotate under the action of the friction force between the roller groove and the wafer. In some embodiments, the support assembly 20 further includes a speed measuring wheel, which is arranged between a pair of rollers, and the three are clamped on the outer edge of the wafer. The speed measuring wheel is used to monitor the running state of the wafer.

[0046] The vibrating plate 30, which is a component of the overflow tank 40 or is disposed on the inner sidewall of the overflow tank 40; the vibrating plate 30 is also called a transducer. The vibrating plate 30 is inclined in the box body 10 to provide high-frequency vibration from the side. The high-frequency sound waves emitted by the vibrating plate 30 act on the surface of the wafer to be cleaned to strip the contaminants attached to the wafer surface. The transducer converts the electrical output of the power supply into a vibration output, and the generated sound waves are transmitted in the fluid. Under the actions of cavitation and acoustic streaming, etc., the particulate matter attached to the wafer surface is stripped;

[0047] The liquid spraying assembly 50 can spray fluid towards the overflow tank 40 to overflow and discharge contaminants such as particulate matter stripped by the high-frequency sound waves from the top of the overflow tank 40. Specifically, the top of the overflow tank 40 is open, and the fluid sprayed by the liquid spraying assembly 50 can fill the overflow tank 40 and overflow from the top opening of the overflow tank 40, so as to discharge the stripped contaminants to between the box body 10 and the overflow tank 40.

[0048] In the present invention, the vibrating plate 30 is disposed 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 vibrating plate 30, ensure effects such as cavitation and acoustic streaming, fully strip the particulate matter from the surface of the wafer, and achieve a good megasonic cleaning effect.

[0049] Specifically, the overflow tank 40 is vertically disposed in the box body 10, the wafer W to be cleaned is disposed along the vertical center line of the overflow tank 40, and the vibrating plate 30 that provides high-frequency sound waves for wafer cleaning is disposed on the side of the vertical center line of the overflow tank 40. That is, the vibrating plate 30 is disposed on the side of the wafer W to be cleaned to provide high-frequency sound waves from the side of the wafer, generate effects of cavitation and acoustic streaming inside the overflow tank 40, strip the particulate matter attached to the wafer surface, and fully clean the wafer surface.

[0050] Such as Figure 3 In the embodiment of, the vibrating plate 30 and other plate members enclose the overflow tank 40, and the support assembly 20 and the liquid spraying assembly 50 are disposed at the bottom of the overflow tank 40. That is, the wafer W to be cleaned is vertically disposed in the overflow tank 40. Such a setting is beneficial to reducing the space for megasonic cleaning of the wafer W, so that the high-frequency sound waves can effectively act on the wafer surface.

[0051] Figure 4 is a schematic diagram of the overflow tank 40 provided by an embodiment of the present invention. The overflow tank 40 includes a tank main body 41, a rectifying portion 42, and a constricting portion 43. Among them, the tank main body 41, the rectifying portion 42, and the constricting portion 43 are sequentially arranged in the vertical direction from bottom to top to form a tank body structure with an open top.

[0052] Furthermore, the tank main body 41 is located at the bottom of the overflow tank 40, and its longitudinal section is a rectangular structure. The support assembly 20 is disposed inside the tank main body 41 to vertically support the wafer to be cleaned.

[0053] Further, compared with other parts of the overflow tank 40, the inner width of the tank body 41 is larger to provide sufficient space for the placement of the support assembly 20. In the present invention, the inner widths of the tank body 41, the rectifying part 42, and the constricting part 43 refer to the lateral widths between the inner sidewalls of the tank body.

[0054] The rectifying part 42 is arranged at the upper end of the tank body 41. Specifically, the rectifying part 42 is a tank body structure, which is vertically arranged above the tank body 41.

[0055] Further, the inner width of the rectifying part 42 suddenly decreases. With such an arrangement, the flow direction of the fluid can be regulated, the fluid disturbance inside the tank body 41 can be avoided, the particles peeled off from the wafer can be prevented from adhering to the wafer surface again, and the cleaning effect of the wafer can be ensured.

[0056] In some embodiments, the inner width of the rectifying part 42 is 1 / 3 - 2 / 3 of the inner width of the tank body 41 to achieve a good rectifying effect. Specifically, the liquid spraying assembly 50 sprays the fluid towards the bottom surface of the tank body 41, and the fluid will repeatedly splash in the tank body 41 to form a turbulent flow. These chaotic fluids become stable after being rectified by the rectifying part 42 with a smaller lateral width; the stable fluid is transmitted upwards through the rectifying part 42 to wash the particles peeled off from the wafer surface and discharge the particles from the top opening of the overflow tank 40.

[0057] Preferably, the inner width of the rectifying part 42 is 1 / 3 - 1 / 2 of the inner width of the tank body 41, so that the fluid sprayed by the liquid spraying assembly 50 becomes stable after being rectified by the rectifying part 42. The rectified fluid can be transmitted upwards substantially along the vertical direction to reduce the backflow and turbulent flow, avoid the peeled particles from adhering to the wafer surface again and causing secondary pollution, and achieve a good cleaning effect.

[0058] Further, the vibration plate 30 extends obliquely outwards along the upper end of the rectifying part 42, as Figure 4 shown. Specifically, the vibration plate 30 extends upwards and outwards from the end of the rectifying part 42, so that the high-frequency sound waves generated by the vibration plate 30 can be obliquely transmitted to the wafer surface to utilize effects such as cavitation and acoustic streaming to peel off the particles on the wafer surface. In the present invention, the outward inclination of the components of the overflow tank 40 means inclining towards the outside of the overflow tank 40, and the inward inclination of the components of the overflow tank 40 means inclining towards the vertical center line of the overflow tank 40.

[0059] Further, the constricting part 43 is a tank body with a trapezoidal longitudinal section, and at least one side plate of the constricting part 43 extends inwards along the upper end of the vibration plate 30, that is, the constricting part 43 extends upwards and inwards. In the present invention, the side plate of the constricting part 43 refers to the plate member located on the side of the vertical center line of the overflow tank 40.

[0060] The inner width of the constriction portion 43 gradually decreases from bottom to top to form a constriction space. The high-frequency sound waves generated by the vibration plate 30 are transmitted in the constriction space between the constriction portion 43 and the wafer W, and are concentrated and transmitted towards the upper part of the wafer W. At the same time, the high-frequency sound waves generated by the vibration plate 30 can be reflected in the constriction space to the wafer surface to enhance the sound pressure intensity of the overflow groove 40 and improve the cleaning effect of the wafer.

[0061] Figure 4 In [the figure], a transmission route diagram of the high-frequency sound waves emitted by the vibration plate 30 between the inner sidewall of the constriction portion 43 and the wafer W is represented by a dashed line. From this, it can be seen that the reflection of the high-frequency sound waves can enhance the efficiency of megasonic cleaning and improve the cleaning effect of the wafer.

[0062] In some embodiments, the angle between the vertical center line of the constriction portion 43 and the overflow groove 40 is 1-15°; preferably, the angle between the vertical center line of the constriction portion 43 and the overflow groove 40 is 1-10°, so as to reasonably control the space between the inner sidewall of the constriction portion 43 and the wafer W and ensure the transmission and reflection effects of the high-frequency sound waves.

[0063] In order to ensure that the inner sidewall of the constriction portion 43 can efficiently reflect sound waves, the roughness of the inner sidewall of the constriction portion 43 should be controlled within Ra0.1. At the same time, the constriction portion 43 should be made of a hydrophobic material to prevent particulate matter from adhering to the inner sidewall of the constriction portion 43. If a large amount of particulate matter adheres to the inner sidewall of the constriction portion 43, the sound waves will undergo diffuse reflection, which is not conducive to maintaining the sound pressure intensity of the overflow groove 40 and is not conducive to achieving a good megasonic cleaning effect.

[0064] In some embodiments, the groove body 41, the rectifying portion 42, and the constriction portion 43 of the overflow groove 40 are made of polytetrafluoroethylene. Polytetrafluoroethylene has high lubricity and non-adhesiveness to prevent particulate matter peeled off by megasonic cleaning from adhering to the inner sidewall of the overflow groove 40 and affecting the reflection of sound waves, so as to control the sound pressure intensity of the overflow groove 40 and ensure a good cleaning effect.

[0065] Figure 5 Shows the sound pressure intensity curve in the overflow groove 40. Since the constriction portion 43 of the overflow groove 40 has the function of sound wave reflection. The sound pressure intensity in this area becomes larger, which is beneficial to strengthening the cavitation and sound wave flow effects of the high-frequency sound waves to fully peel off the particulate matter on the wafer surface and achieve the cleaning of the particulate matter on the wafer surface.

[0066] During the 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, so as to clean each area of the wafer and avoid the occurrence of blind spots in megasonic cleaning that affect the cleaning effect of the wafer.

[0067] In the present invention, the vibration plate 30 is arranged facing the surface of the wafer W to be cleaned to emit high-frequency sound waves towards the surface to be cleaned. Figure 4In this case, the vibration plate 30 is disposed on one side of the wafer W to be cleaned, that is, the vibration plate 30 faces the front side of the wafer, so as to clean the surface of the wafer by megasonic cleaning. In the present invention, the so-called front side of the wafer refers to the side where the electronic devices are arranged; the so-called back side of the wafer refers to the non-arrangement surface of the electronic devices, that is, the opposite side of the front side of the wafer.

[0068] As an aspect of this embodiment, the angle between the vibration plate 30 and the horizontal plane is 2-30°; preferably, the angle between the vibration plate 30 and the horizontal plane is 5-15°, so that the high-frequency sound waves emitted by the vibration plate 30 are transmitted obliquely upward, so as to fully peel off the particulate matter on the surface of the wafer. During megasonic cleaning, the wafer rotates around the central axis under the drive of the support assembly 20, so that the high-frequency sound waves emitted by the vibration plate 30 can act on the surface of the wafer comprehensively.

[0069] In the present invention, the vibration plate 30 is inclined, and the component of the sound wave it emits can be perpendicular to the surface of the wafer, which is beneficial to improving the removal rate and ensuring the cleaning effect of the wafer; at the same time, the inclined setting of the vibration plate 30 is beneficial to reducing the interference of bubbles during the cleaning process and enhancing the vibration effect on particles.

[0070] 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 dimension 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 contracting portion 43. The width of the vibration plate 30 is set within a certain range, which can ensure that the high-frequency sound waves emitted by the vibration plate 30 cover along the radial direction of the wafer as much as possible, and ensure the cleaning effect of the wafer.

[0071] It can be understood that the width of the vibration plate 30 should not be too large, so as to control the size of the overflow tank 40, reduce the usage amount of the cleaning liquid, and control the wafer cleaning cost. Preferably, the width of the vibration plate 30 is 15-30 mm.

[0072] In the present invention, the vibration plate 30 extends along the horizontal direction ( Figure 7 shown), and its transverse length should be greater than the diameter of the wafer, or the transverse 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.

[0073] As an embodiment of the present invention, the vibration plate 30 is made of electroacoustic material. Specifically, the vibration plate 30 is made of piezoelectric material to convert electrical energy into vibration and form high-frequency sound waves. Preferably, the vibration plate 30 is made of lead zirconate titanate (PZT) piezoelectric ceramics, barium titanate (BaTiO 3 ) piezoelectric ceramics, etc.

[0074] As an embodiment of the present invention, at least a part of the vibration plate 30 is located below the central axis of the wafer to be cleaned, so as to ensure that the high-frequency sound waves emitted by the vibration plate 30 can be transmitted along the radial direction. The wafer rotates around the central axis during megasonic cleaning, so that the high-frequency sound waves can fully cover all areas of the wafer.

[0075] Figure 4 In the illustrated embodiment, the horizontal distance between the rectifying portion 42 and the vertical center line of the overflow tank 40 is smaller than the horizontal distance between the constricting portion 43 and the vertical center line of the overflow tank 40. Since the constricting portion 43 is inclined upward and inward from the upper end of the vibration plate 30, the horizontal distance between the upper end of the constricting portion 43 and the vertical center line of the overflow tank 40 is the smallest. In this embodiment, the horizontal distance between the rectifying portion 42 and the vertical center line of the overflow tank 40 is smaller than the minimum horizontal distance between the constricting portion 43 and the vertical center line of the overflow tank 40. In the present invention, the horizontal distance between the rectifying portion 42 and the vertical center line of the overflow tank 40 refers to the horizontal distance between the inner side wall of the rectifying portion 42 and the vertical center line, and the horizontal distance between the constricting portion 43 and the vertical center line of the overflow tank 40 refers to the horizontal distance between the inner side wall of the constricting portion 43 and the vertical center line.

[0076] As an aspect of this embodiment, the horizontal distance between the rectifying portion 42 and the vertical center line of the overflow tank 40 is 2 - 15 mm, and the horizontal distance between the constricting portion 43 and the vertical center line of the overflow tank 40 is 5 - 25 mm. With such a setting, it is beneficial to control the internal space of the overflow tank 40, improve the sound pressure intensity inside the overflow tank 40, meet the requirements of wafer megasonic cleaning, and obtain a good cleaning effect.

[0077] Figure 4 In [the device], the side plates of the constricting portion 43 opposite to the wafer cleaning surface are inclined, while the side plates of the constricting portion 43 opposite to the wafer cleaning surface are vertically arranged to narrow the internal space of the overflow tank 40 and control the sound pressure intensity of the overflow tank 40.

[0078] In addition, since the overflow tank 40 is configured with the rectifying portion 42 and the constricting portion 43, its internal volume becomes smaller, which is beneficial to reducing the usage amount of the cleaning liquid and controlling the cost of wafer cleaning. That is, the liquid spraying assembly 50 provided at the lower part of the overflow tank 40 only needs to spray a small amount of cleaning liquid to fill the overflow tank 40, so as to clean the particulate matter in the overflow tank 40 by means of overflow. In some embodiments, Figure 3 The illustrated wafer cleaning device can save 5 - 20 L of cleaning liquid per hour to control the cost of wafer post-treatment. When cleaning the wafer, it is necessary to regularly supply cleaning liquid to the inside of the overflow tank 40. Since the volume of the overflow tank 40 provided by the present invention is small, the usage amount of the cleaning liquid can be reduced.

[0079] To ensure good overflow effect and timely clean the particulate matter in the overflow tank 40, the liquid spraying assembly 50 is arranged below the vibrating plate 30, so that the fluid sprayed by the liquid spraying assembly 50 is far away from the vibrating plate 30, avoiding the influence of the turbulent fluid on the high-frequency sound waves emitted by the vibrating plate 30 and avoiding the mutual influence between megasonic cleaning and overflow drainage.

[0080] Furthermore, the support assembly 20 is located in the tank body 41 of the overflow tank 40, the liquid spraying assembly 50 is located below the support assembly 20, and the cleaning liquid sprayed by the liquid spraying assembly 50 faces the bottom of the tank body 41.

[0081] In the present invention, the spraying direction of the liquid spraying assembly 50 is inclined downward to spray the fluid towards the bottom surface of the tank body 41. The liquid spraying assembly 50 sprays the fluid downward so that the fluid is as far away from the wafer being megasonic cleaned as possible to reduce the influence of the sprayed fluid on megasonic cleaning; this is because the fluid sprayed by the liquid spraying assembly 50 is mainly used for overflow to wash the stripped particulate matter, rather than cleaning the particulate matter on the surface of the wafer through the washing action. Setting the spraying direction of the liquid spraying assembly 50 to be inclined downward is beneficial to ensuring the effect of megasonic cleaning.

[0082] Furthermore, the liquid spraying assembly 50 includes at least a pair of spray pipes, which are arranged in the tank body 41 of the overflow tank 40 and spray the cleaning liquid towards the inside of the overflow tank 40. The spray pipes are configured with liquid spraying ports, and the number of the liquid spraying ports is multiple, which are arranged at intervals along the length direction of the spray pipes. At the same time, in order to control the sputtering degree of the fluid sprayed by the liquid spraying assembly 50, the adjacent liquid spraying ports are arranged at intervals, and the liquid spraying ports of the adjacent spray pipes are staggered with each other to reduce the counterflow and / or intersection of the fluid inside the tank body 41, and try to control the disturbance degree of the fluid to ensure that the fluid passing through the rectifying part 42 becomes relatively stable to a certain extent.

[0083] It can be understood that the liquid spraying port can be a spray pipe, or a nozzle can be installed at the position of the liquid spraying port to supply the cleaning liquid to a fixed point of the overflow tank 40. In some embodiments, the nozzle installed at the liquid spraying port can be a columnar nozzle or a conical nozzle to disperse the sprayed fluid in the chamber of the tank body 41.

[0084] Figure 6 It is a flow field diagram inside the circular cleaning device provided by an embodiment of the present invention, which specifically shows the flow condition of the cleaning liquid in the overflow tank 40. After the rectifying treatment of the cleaning liquid inside the tank body 41 by the rectifying part 42, the flow direction of the fluid is generally vertically upward to effectively reduce the disturbance and backflow of the fluid in the overflow tank 40.

[0085] Specifically, the cleaning liquid sprayed by the liquid spraying assembly 50 ( Figure 4 shown) flows along the vertical direction towards the overflow tank 40 to push the particulate matter stripped by megasonic cleaning to move upward, and finally flows to the space between the overflow tank 40 and the box body 10 through the upper edge of the overflow tank 40.

[0086] Figure 7 FIG. 2 is a schematic diagram of a wafer cleaning apparatus 100 provided by another embodiment of the present invention. Compared with the embodiment shown in Figure 3 FIG. 3, the structure of the overflow tank 40 and the number of the vibration plates 30 are different.

[0087] Figure 8 is Figure 7 a schematic diagram of the overflow tank 40 in the embodiment shown in FIG. 3. The wafer cleaning apparatus 100 is configured with a pair of vibration plates 30 symmetrically arranged on both sides of the overflow tank 40. That is, the configured pair of vibration plates 30 can respectively clean the front and back surfaces of the wafer W, realizing double-sided cleaning of the wafer.

[0088] The vibration plate 30 is arranged between the rectifying portion 42 and the constricting portion 43. Moreover, the vibration plate 30 is inclined upward and outward from the upper end of the rectifying portion 42, so that the high-frequency sound waves emitted by the vibration plate 30 can propagate toward the surface of the wafer, and under the action of effects such as cavitation and acoustic streaming, the particulate matter on the wafer surface can be peeled off.

[0089] Compared with Figure 4 the structure of the overflow tank 40 shown in FIG. 3, the constricting portion 43 adopts a symmetric structure. That is, a constricting structure is formed at the upper end of the overflow tank 40. When the fluid in the overflow tank 40 passes through the constricting structure, its flow rate will increase appropriately, and the cleaning liquid containing particulate matter can quickly overflow from the top of the overflow tank 40.

[0090] It can be understood that when megasonic cleaning is required for one side of the wafer, the symmetric structure of the overflow tank 40 shown in Figure 8 FIG. 3 can also be adopted to ensure the rapid overflow of the cleaning liquid, and the particulate matter peeled off by megasonic cleaning is discharged to the space between the overflow tank 40 and the box body 10 by means of overflow. That is, the part above the rectifying portion 42 also adopts a symmetric structure with respect to the vertical center line. According to actual needs, one or two vibration plates 30 are arranged between the rectifying portion 42 and the constricting portion 43.

[0091] It should be noted that the inclination angles and performance parameters of the vibration plates 30 arranged on the front and back surfaces of the wafer can be different to adapt to the characteristics of the front and back surfaces of the wafer and improve the effect of megasonic cleaning.

[0092] Figure 9 is Figure 7 the sound pressure intensity curve of the overflow tank 40 of the wafer cleaning apparatus 100 shown in FIG. 3. Among them, the abscissa is the vertical position of the wafer. Specifically, the abscissa defines the position of the wafer with the lower edge of the wafer as the zero point; the ordinate is the sound pressure at the corresponding position of the overflow tank 40.

[0093] Figure 7 In FIG. 3, the vibration plate 30 is arranged at a position below the central axis of the wafer, that is, the vibration plate 30 is arranged within the coordinate range of 100 mm - 150 mm. FromFigure 9 It can be seen that the intensity of the high-frequency sound waves emitted by the vibration plate 30 does not significantly attenuate, and the overall sound pressure in the overflow tank 40 is maintained within a relatively high range.

[0094] Figure 10 is the sound pressure intensity curve corresponding to the megasonic cleaning device ( Figure 1 shown) in the prior art. The meanings of its abscissa and ordinate are the same as Figure 9 . Since the megasonic vibration plate 20' is placed at the bottom of the cleaning tank 10', it is relatively far from the wafer to be cleaned. The high-frequency sound waves emitted by the megasonic vibration plate 20' attenuate significantly in the fluid, resulting in a decrease in the sound pressure intensity in the overflow tank 40, which is not conducive to fully peeling off the particulate matter on the wafer surface.

[0095] In the present invention, the vibration plate 30 is inclined and disposed in a region slightly below the central axis of the wafer, effectively reducing the sound pressure attenuation. The overall sound pressure in the overflow tank 40 is relatively high, so as to fully peel off the particulate matter on the wafer surface. The configured overflow tank 40 can rectify the fluid inside to avoid the reattachment of particulate matter, so as to obtain wafers with cleanliness meeting the requirements.

[0096] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0097] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A wafer cleaning device, characterized in that, it includes: a box body with an overflow tank arranged inside; a support assembly arranged in the overflow tank to support and drive the wafer to rotate; a liquid spraying assembly arranged in the overflow tank to spray liquid towards the bottom of the overflow tank; the overflow tank includes a tank main body, a rectifying part and a constricting part. The tank main body is a rectangular tank body, and the rectifying part and the constricting part are sequentially arranged above the tank main body; a vibrating plate is arranged between the rectifying part and the constricting part, which is inclined and emits high-frequency sound waves towards the wafer; the rectifying part is a rectangular tank body, and its internal width is smaller than the internal width of the tank main body; the fluid moving upward through the rectifying part can discharge the contaminants stripped by the high-frequency sound waves from the top of the overflow tank.

2. The wafer cleaning device according to claim 1, characterized in that, the vibrating plate is arranged on the side of the vertical center line of the overflow tank and extends obliquely upward and outward.

3. The wafer cleaning device according to claim 2, characterized in that, the included angle between the vibrating plate and the horizontal plane is 2 - 30°.

4. The wafer cleaning device according to claim 1, characterized in that, the constricting part is a tank body with a trapezoidal longitudinal section, and its side plate extends obliquely upward and inward.

5. The wafer cleaning device according to claim 4, characterized in that, the included angle between the side plate of the constricting part and the vertical center line of the overflow tank is 1 - 15°.

6. The wafer cleaning device according to claim 1, characterized in that, the support assembly and the liquid spraying assembly are arranged in the tank main body, and the liquid spraying assembly is located below the support assembly.

7. The wafer cleaning device according to claim 1, characterized in that, the internal width of the rectifying part is 1 / 3 - 2 / 3 of the internal width of the tank main body.

8. The wafer cleaning device according to claim 1, characterized in that, the transverse dimension of the constricting part is less than or equal to the transverse dimension of the tank main body.

9. The wafer cleaning device according to claim 1, characterized in that, at least part of the vibrating plate is located below the central axis of the wafer to be cleaned.

10. The wafer cleaning device according to claim 1, characterized in that, the width of the vibrating plate is 10 - 50 mm.

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