CN219233235U

CN219233235U - Rolling brush assembly for cleaning wafer

Info

Publication number: CN219233235U
Application number: CN202223508063.7U
Authority: CN
Inventors: 曹自立; 姚福聪; 李长坤
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-06-23
Anticipated expiration: 2032-12-28

Abstract

The utility model provides a rolling brush assembly for cleaning a wafer, which comprises the following components: the surface of the roller is provided with a plurality of evenly distributed liquid outlet holes; the first fixing piece is arranged at one end of the roller and is provided with a liquid inlet communicated with the roller; the second fixing piece is arranged at the other end of the roller and used for enabling the roller to rotate under the action of an external driving device; a sponge which covers the outer surface of the roller and is formed into a whole; an inner core is also arranged in the roller, and the surface of the inner core is provided with a core hole, so that after the cleaning liquid flows into the inner core through the liquid inlet, the cleaning liquid is discharged from the liquid outlet to the sponge after flowing uniformly through the core hole; the core holes are distributed at equal intervals along a spiral line on the circumferential surface of the inner core. According to the utility model, the inner core is additionally arranged, so that the flow velocity distribution of the cleaning liquid in the roller can be effectively regulated, and the cleaning liquid can be uniformly discharged along the axial direction of the roller.

Description

Rolling brush assembly for cleaning wafer

Technical Field

The utility model belongs to the technical field of wafer production, and particularly relates to a rolling brush assembly for cleaning a wafer.

Background

The integrated circuit industry is the core of the information technology industry and plays a key role in the process of converting and upgrading the boosting manufacturing industry into digital and intelligent conversion. The chip is a carrier of an integrated circuit, and the chip manufacturing involves the technological processes of chip design, wafer manufacturing, wafer processing, electrical measurement, dicing packaging, testing, and the like. Wherein, the chemical mechanical polishing belongs to the wafer manufacturing procedure, and the chemical mechanical polishing is an ultra-precise surface processing technology of global planarization.

After chemical mechanical polishing, the wafer needs to be subjected to post-treatments such as cleaning, drying and the like. The purpose of wafer cleaning is to avoid pollution of trace ions and metal particles to semiconductor devices and ensure the performance and qualification rate of the semiconductor devices.

Wafer cleaning methods generally include: rolling brush cleaning, megasonic cleaning and the like, wherein the rolling brush cleaning has wider application. The rolling brush cleaning can be classified into vertical rolling brush cleaning and horizontal rolling brush cleaning according to the placed state of the wafer. The vertical cleaning device of wafer includes the cell body, and the inside of cell body is provided with roller assembly to vertical support wafer drives its rotation, and the round brush that sets up in the wafer both sides rolls around its axis, with the particulate matter on contact cleaning wafer surface, the removal wafer surface.

The rolling brush generally comprises a hollow shaft and a sponge coated on the periphery of the hollow shaft, the rolling brush is arranged on a pair of rotatable rolling brush fixing structures, a liquid inlet shaft is arranged on one end of the rolling brush, liquid (cleaning liquid or rinsing liquid) is supplied to the interior of the hollow shaft through the liquid inlet shaft, and columnar liquid flow is sprayed. The hollow shaft is uniformly provided with a plurality of liquid outlet holes, so that liquid in the shaft can pass through the liquid outlet holes to reach the sponge and seep out from the sponge, thereby moisturizing the rolling brush, forming a liquid film on the surface of the sponge, and preventing the sponge from directly contacting with the wafer caused by the back adhesion of pollutants on the sponge.

However, in the actual use process, the liquid supplied in the hollow shaft cannot generally and uniformly reach the sponge along the axial direction, so that the axial liquid outlet of the sponge is uneven, the surface of part of the rolling brush is not discharged or the liquid outlet amount is insufficient, and pollutants on the rolling brush are easy to be sticky back to pollute the wafer, and the brushing effect is affected.

Disclosure of Invention

The present utility model aims to solve at least one of the technical problems in the related art to some extent. Therefore, the utility model provides a rolling brush assembly for cleaning a wafer.

The embodiment of the utility model provides a rolling brush assembly for cleaning a wafer, which comprises the following components:

the surface of the roller is provided with a plurality of evenly distributed liquid outlet holes;

the first fixing piece is arranged at one end of the roller and is provided with a liquid inlet communicated with the roller;

the second fixing piece is arranged at the other end of the roller and used for enabling the roller to rotate under the action of an external driving device;

a sponge which covers the outer surface of the roller and is formed into a whole;

an inner core is also arranged in the roller, and the surface of the inner core is provided with a core hole, so that after the cleaning liquid flows into the inner core through the liquid inlet, the cleaning liquid is discharged from the liquid outlet to the sponge after flowing uniformly through the core hole;

the core holes are distributed at equal intervals along a spiral line on the circumferential surface of the inner core.

In some embodiments, the core includes a front end, a body, and a rear end, with a stepped structure of trapezoidal cross section formed between the front end and the body.

In some embodiments, the front end is provided with water outlets near the edge of the step structure and/or the surface of the step structure.

In some embodiments, at least a portion of the water outlet is formed as an inclined hole forming an angle of 30-75 ° with the circumference of the body.

In some embodiments, a tensioning buckle for clamping and fixing the inner core in the roller is detachably arranged at the front end.

In some embodiments, the tensioning clasp comprises a distal base and a plurality of fingers extending perpendicularly along the base surface that expand outwardly while clasping the inner core by the elastic force of its material.

In some embodiments, the outer diameter of the rear end is greater than the outer diameter of the body such that an annular step surface is formed between the rear end and the body.

The first fixing piece stretches into the rear end and is in butt joint communication with the rear end.

In some embodiments, the surface of the trailing end is circumferentially configured with a plurality of drain holes.

In some embodiments, an annular groove is formed in the inner peripheral surface of the end portion of the rear end, and the inner core is pulled out of the roller through the assembly and disassembly tool matched with the annular groove.

In some embodiments, a gap is left between the outer circumferential surface of the inner core and the inner circumferential surface of the roller.

Compared with the prior art, the utility model has the beneficial effects that:

the utility model maintains the main structure of the existing rolling brush component, an inner core with a porous structure is additionally arranged on the basis, the inner core and the roller are coaxially arranged, cleaning liquid is injected into the inner core through the liquid inlet in the first fixing piece, the cleaning liquid is uniformly distributed in the inner core for the first time along with synchronous rotation of the inner core and the roller, the cleaning liquid is thrown into the roller through the core holes of the inner core under the action of centrifugal force, the cleaning liquid is uniformly distributed for the second time through the rotation of the roller, the cleaning liquid is uniformly distributed to liquid outlet holes at all positions of the roller in the axial direction, and the cleaning liquid is thrown out to a sponge through the liquid outlet holes under the action of centrifugal force. The inner core is additionally arranged, so that the flow velocity distribution of the cleaning liquid in the roller can be effectively regulated, and the cleaning liquid can be uniformly discharged along the axial direction of the roller.

Drawings

The advantages of the present utility model will become more apparent and more readily appreciated from the detailed description given in conjunction with the following drawings, which are meant to be illustrative only and not limiting of the scope of the utility model, wherein:

FIG. 1 is a schematic view of a conventional rolling brush assembly according to an embodiment of the present utility model;

FIG. 2 is a graph showing axial liquid discharge of a conventional roller brush assembly according to an embodiment of the present utility model;

FIG. 3 is a schematic view of a roller brush assembly with an inner core according to an embodiment of the present utility model;

FIG. 4 is a perspective view of an inner core provided in an embodiment of the present utility model;

FIG. 5 is another perspective view of an inner core provided in accordance with one embodiment of the present utility model;

fig. 6 is a perspective view of the front end of the core provided by an embodiment of the present utility model;

FIG. 7 is a cross-sectional view of the front end of the core provided by an embodiment of the present utility model;

FIG. 8 is an assembly view of a roller brush assembly according to an embodiment of the present utility model;

fig. 9 is a graph of axial run-out of a roll brush assembly having an inner core according to an embodiment of the present utility model.

Detailed Description

The technical scheme of the utility model is described in detail below with reference to specific embodiments and attached drawings. The examples described herein are specific embodiments of the present utility model for illustrating the concept of the present utility model; the description is intended to be illustrative and exemplary in nature and should not be construed as limiting the scope of the utility model in its aspects. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims of the present application and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein.

The drawings in the present specification are schematic views, which assist in explaining the concept of the present utility model, and schematically show the shapes of the respective parts and their interrelationships. It should be understood that for the purpose of clearly showing the structure of various parts of embodiments of the present utility model, the drawings are not drawn to the same scale and like reference numerals are used to designate like parts in the drawings. The technical scheme of the utility model is further described by the following specific embodiments.

In the present utility model, the Wafer (W) is also called a Substrate (Substrate), and the meaning and actual function are equivalent.

The wafer cleaning device comprises a groove body, a rolling brush assembly and a wafer supporting device, wherein the rolling brush assembly and the wafer supporting device are positioned in the groove body, and the wafer supporting device is used for vertically supporting and positioning a wafer W to be cleaned. The two sides of the wafer W are provided with rolling brush assemblies, and the end parts of the rolling brush assemblies are connected with driving motors which drive the rolling brush assemblies to rotate around the axes of the rolling brush assemblies. The upper part of the tank body is provided with a spray pipeline for spraying DIW and/or cleaning liquid to the wafer W.

The roll brush assembly is capable of adsorbing a large amount of cleaning liquid for brushing the surface of the wafer W. The rolling brush assembly contacts the rotating wafer W to remove contaminants from the surface of the wafer W. The roll brush assemblies located at both sides of the wafer W may be moved in a horizontal direction to be away from or close to the wafer W. When the rolling brush assembly is far away from the wafer W, a certain gap is reserved between the rolling brush assembly and the wafer W, and the wafer carrying manipulator can clamp the wafer W to take away the wafer W which is completely cleaned; the rolling brush assembly moves close to the wafer W, and the rolling brush assembly is abutted against the wafer W and is used for cleaning the surface of the wafer W in a contact mode.

Fig. 1 shows a conventional rolling brush assembly, which comprises a roller 100 and a sponge 200 wrapped around the periphery of the roller 100, wherein a plurality of liquid outlet holes 110 are formed in the periphery of the roller 100, two ends of the roller 100 are respectively fixedly supported by a first fixing piece 300 and a second fixing piece 400, wherein a liquid inlet is formed in the first fixing piece 300 along the axial direction, the liquid inlet is communicated with the interior of the roller 100, cleaning liquid is injected into the interior of the roller 100 through the liquid inlet, and is discharged from the liquid outlet holes 110 under the action of centrifugal force along with the rotation of the roller 100 and absorbed by the sponge 200.

However, the chemical mechanical polishing machine table generally adopts rolling brush assemblies with different specifications and types, and the sizes and distribution of the liquid outlet holes 110 of the rolling brush assemblies with different specifications are different, so that in the cleaning process, the rolling brush assemblies with different specifications and types cannot be adapted due to factors such as injection pressure of cleaning liquid, and the cleaning liquid introduced into the roller 100 cannot uniformly reach the sponge 200 wrapped around the periphery along the axial direction of the rolling brush assemblies. The axial liquid outlet on the surface of the sponge 200 is uneven, so that partial areas on the surface of the rolling brush assembly are not discharged or the liquid outlet amount is insufficient, and finally, pollutants on the rolling brush assembly are easy to back adhere to pollute the wafer, and the brushing effect is affected.

As can be seen from the axial liquid outlet condition of the sponge 200 shown in fig. 2, for small-flow liquid inlet, the liquid outlet amount at one end of the rolling brush assembly close to the liquid inlet is maximum, and gradually decreases along the axial liquid outlet amount until no liquid is discharged at the farthest end; for medium-flow liquid inlet, the liquid outlet amount of the middle area of the rolling brush assembly is larger, and the flow at the two ends is smaller; for high flow rates of feed liquid. The end of the rolling brush component, which is close to the liquid inlet, is free from liquid, the liquid outlet amount is gradually increased along the axial direction, and the liquid outlet amount is the largest at the far end. Therefore, no matter how large the flow of the cleaning liquid is, even liquid distribution cannot be realized.

To at least solve the above technical problems, an embodiment of the present utility model provides a rolling brush assembly for cleaning a wafer, as shown in fig. 3, including:

the surface of the roller 100 is provided with a plurality of evenly distributed liquid outlet holes 110;

a first fixing member 300 disposed at one end of the drum 100 and having a liquid inlet communicating with the drum 100;

a second fixing member 400 disposed at the other end of the drum 100 for rotating the drum 100 under the action of an external driving device;

a sponge 200 which covers the outer surface of the drum 100 and is formed in one body;

the inner core 500 is also arranged in the roller 100, and the surface of the inner core is provided with a core hole 521, so that the cleaning liquid flows into the inner core 500 through the liquid inlet, flows uniformly through the core hole 521 and then is discharged from the liquid outlet 110 to reach the sponge 200;

the core holes 521 are equally spaced along the spiral on the circumferential surface of the inner core 500.

The main structure of the existing rolling brush assembly is reserved, an inner core 500 with a porous structure is additionally arranged on the basis, the inner core 500 and the roller 100 are coaxially arranged, cleaning liquid is injected into the inner core 500 through a liquid inlet in the first fixing piece 300, along with synchronous rotation of the inner core 500 and the roller 100, the cleaning liquid is uniformly distributed for the first time in the inner core 500, the cleaning liquid is thrown into the roller 100 through a core hole 521 of the inner core 500 under the action of centrifugal force, the cleaning liquid is uniformly distributed for the second time through rotation of the roller 100, the cleaning liquid is uniformly distributed to liquid outlet holes 110 at all positions of the roller 100, and the cleaning liquid is thrown out to a sponge 200 through the liquid outlet holes 110 under the action of centrifugal force. The inner core 500 is additionally arranged to effectively adjust the flow velocity distribution of the cleaning liquid in the roller 100, so that the cleaning liquid can be uniformly discharged along the axial direction of the roller 100, and the phenomenon of drift of a dry pipe is avoided.

The plurality of core holes 521 formed on the outer circumference of the inner core 500 spray the cleaning liquid toward different directions around the inner core 500, preferably, an angle between two adjacent core holes 521 is 90 ° so that the core holes 521 spray the cleaning liquid toward 4 different directions. The core holes 521 are spirally distributed around the circumference of the inner core 500 along the axial direction of the inner core 500, and on the premise that the number of the core holes 521 is within a reasonable range, uniform flow distribution effects in different directions and in the axial direction of the inner core 500 are ensured.

In addition, the inner core 500 may be combined with the roll 100 to form an integral structure (as shown in fig. 8), that is, a double-layered sleeve structure composed of the inner core 500 and the roll 100 nested with each other, the inner core 500 performs an axial uniform flow function, and the outer layer roll 100 distributes the uniform flow cleaning liquid into the circumferential sponge 200 structure.

The rolling brush assembly provided by the embodiment can greatly improve the distribution uniformity of the cleaning liquid on the sponge 200, so that the sponge 200 is soaked with the cleaning liquid everywhere, as can be seen from the axial liquid outlet condition graph of the sponge 200 provided by fig. 9, the liquid outlet amounts at the axial positions of the rolling brush assembly are almost consistent, which indicates that the inner core 500 provided by the embodiment plays a uniform flow and uniform distribution effect of the cleaning liquid.

In the embodiment shown in fig. 4 and 5, the core 500 includes a front end 530, a main body 520, and a rear end 510, and a stepped structure 540 having a trapezoidal cross section is formed between the front end 530 and the main body 520.

In this embodiment, the inner core 500 is composed of a front end 530, a main body 520 and a rear end 510, wherein the rear end 510 is mainly used for being assembled and fixed with the end of the roller 100, and the rear end 510 is in butt joint with the first fixing member 300 to realize the conduction of the cleaning fluid flow channel. The front end 530 is then secured to the interior of the roll 100 in cooperation with the tension clasp 600 to support and position the core 500. The main body 520 mainly plays a uniform flow distribution role, the cleaning solution entering the inner core 500 is substantially uniformly dispersed in the roller 100 along the axial direction, and then the cleaning solution is supplied to the sponge 200 through the liquid outlet holes 110 on the side surface of the roller 100, so that the sponge 200 is uniformly discharged along the axial direction of the rolling brush assembly, a continuous and complete liquid film is formed on the surface of the sponge 200, and the contaminants adhered on the rolling brush assembly are prevented from being re-adhered to the surface of the wafer W.

It should be noted that, on the basis of the structure of the inner core 500 provided by the present utility model, preferably, the main body 520 may be designed to be a tapered structure, that is, the inner diameter of the main body 520 gradually decreases along the direction from the rear end 510 to the front end 530, and for the cleaning fluid flow with smaller inflow rate, since the inner diameter of the main body 520 gradually decreases, the flow rate of the cleaning fluid in the small inner diameter area will be further increased under the same inflow pressure, so that the cleaning fluid also has a higher and stable flow rate in the front end 530 area of the inner core 500, and further it is ensured that the cleaning fluid can flow through the far end of the inner core 500.

In the embodiment shown in fig. 6, the front end 530 is provided with water outlet holes 531 near the edge of the step structure 540 and/or at the surface of the step structure 540.

In the embodiment shown in fig. 7, at least a portion of the water outlet 531 is formed as an inclined hole forming an angle of 30-75 ° with the circumference of the main body 520.

The front end 530 of the inner core 500 is inserted to the deepest part of the roll 100, and the front end 530 of the inner core 500 is formed in a reduced diameter structure, so that the inner core 500 is convenient to enter the inside of the tension buckle 600; in addition, since the depths of the rolls 100 of different specifications are different, in order to adapt to the rolls 100 of different depths, the length of the inner core 500 is smaller than the length of the rolls 100, and it is ensured that a gap of 10-20mm is left between the front end 530 of the inner core 500 and the deepest part of the rolls 100 after the inner core 500 is inserted into the rolls 100.

In order to ensure that the area of the roller 100 corresponding to the gap can uniformly discharge liquid, 2-12 diagonally sprayed water outlet holes 531 are formed in the front end 530, and the water outlet holes 531 of the front end 530 spray cleaning liquid in the deepest direction of the roller 100, so as to provide cleaning liquid for the gap area where the inner core 500 cannot reach.

In the embodiment shown in fig. 4, a tensioning clasp 600 for clamping and securing the core 500 within the roll 100 is removably provided at the front end 530.

The tensioning buckle 600 provided in this embodiment is disposed at the front end 530 of the portion of the inner core 500 inserted into the roller 100, and is used for supporting and positioning the inner core 500, so as to prevent the inner core 500 from shaking in the roller 100, and ensure the stability of the inner core 500 during the rotation of the roller 100.

Specifically, the inner core 500 extends axially along the roller 100 and is inserted into the tensioning buckle 600, the tensioning buckle 600 is extruded by the front end 530 of the inner core 500 and expands outwards to prop against the inner wall of the roller 100, the inner core 500 is supported and fixed, the axial freedom degree of the inner core 500 is limited, the movement states of the inner core 500 and the roller 100 are bound, and the second fixing piece 400 drives the roller 100 to rotate and simultaneously drives the inner core 500 to rotate.

In this embodiment, the tension clasp 600 includes a distal base and a plurality of fingers extending perpendicularly along the surface of the base that simultaneously engage the inner core 500 by the elastic force of its material while expanding outwardly.

The split type fixing scheme of the inner core 500 combined with the tensioning buckle 600 is adopted in the embodiment, and certain adaptability is provided for the depth and diameter change of the roller 100, so that the roller brush assemblies of different specifications and models can be compatible, the problem of uneven axial liquid discharge of the roller brush assemblies of different specifications and models is solved, and the wafer W brushing effect is improved. In addition, the inner core 500 can be reused, and the inner core is not required to be replaced together with consumable materials such as the sponge 200, so that the effect is improved, and the consumable material cost is not additionally increased.

It should be noted that, the base provided in this embodiment is circular, and the finger is led out from the edge of the circular base and is perpendicular to the base. The diameter of the front end 530 is slightly larger than that of the base, after the inner core 500 is inserted into the tensioning buckle 600, the proximal end 530 promotes outward expansion of the clamping fingers at the periphery of the base to a certain extent so as to abut against the inner wall of the roller 100, at this time, a gap is still reserved between the proximal end 530 of the inner core 500 and the base, and the cleaning fluid discharged from the water outlet 531 of the front end 530 can flow out from the gap. In addition, the gap between the front end 530 and the roller 100 is slightly smaller than the thickness of the clamping finger, so that after the clamping finger expands, the inner side surface and the outer side surface of the clamping finger are respectively extruded by the outer wall of the front end 530 and the inner wall of the roller 100, and interference fit is formed among the inner core 500, the clamping finger and the roller 100, so that the inner core 500 is supported and fixed.

In the embodiment shown in fig. 4 and 5, the outer diameter of the rear end 510 is greater than the outer diameter of the body 520 such that an annular step surface is formed between the rear end 510 and the body 520.

The first mount 300 extends into the interior of the rear end 510 and is in abutting communication with the rear end 510.

In this embodiment, the rear end 510 is formed with an annular step surface, and cooperates with the first fixing member 300 to achieve the butt-joint fixation between the first fixing member 300 and the inner core 500, so that the liquid inlet on the first fixing member 300 communicates with the inner core 500.

In the embodiment shown in fig. 4, the surface of the rear end 510 is circumferentially configured with a plurality of drain holes 510.

In this embodiment, a plurality of drain holes 510 are equidistantly distributed on the sidewall of the rear end 510, for supplying liquid to the sponge 200 area corresponding to the rear end 510.

In this embodiment, an annular groove is formed in the inner circumferential surface of the end portion of the rear end 510, and the inner core 500 is pulled out of the roll 100 by fitting a loading and unloading tool with the annular groove.

Since the end face of the rear end 510 of the core 500 is almost flush with the end face of the roll 100 after the core 500 is inserted into the roll 100, the core 500 is not easily removed when being replaced. For this, the present embodiment provides annular grooves of a specific structure on the end surface and inner surface of the rear end 510, so that the inner core 500 can be easily removed from the roll 100 by inserting the annular grooves with a specific loading and unloading tool.

The end face of the rear end 510 is also provided with a square liquid inlet pipe orifice, the liquid inlet pipe orifice is in butt joint with the first fixing piece 300 arranged on the machine table, and a circular truncated cone-shaped side wall is formed between the liquid inlet pipe orifice and the rear end 510. The inner wall of one end of the roll 100 near the rear end 510 is formed with a step surface matching with the shape of the side wall of the liquid inlet pipe orifice, and when the inner core 500 is inserted into the roll 100, the liquid inlet pipe orifice is embedded into the step surface, and at this time, the end surface of the rear end 510 is flush with the end surface of the roll 100.

In the embodiment shown in fig. 8, a gap is left between the outer circumferential surface of the inner core 500 and the inner circumferential surface of the roll 100.

After the cleaning solution is injected from the end part of the inner core 500, the cleaning solution is uniformly distributed for the first time along with the rotation of the inner core 500, and is thrown out into an annular cavity between the inner core 500 and the roller 100 through the core holes 521, and the cleaning solution is uniformly distributed for the second time along with the rotation of the roller 100 in the annular cavity. Alternatively, the width of the annular gap between the inner core 500 and the roll 100 is 1 to 1.5 times the inner diameter of the inner core 500.

The applicant declares that the above is only a specific embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present utility model disclosed by the present utility model fall within the scope of the present utility model and the disclosure.

Claims

1. A roll brush assembly for wafer cleaning, comprising:

2. The roll brush assembly for wafer cleaning according to claim 1, wherein the inner core includes a front end, a main body, and a rear end, and a stepped structure having a trapezoidal cross section is formed between the front end and the main body.

3. The roll brush assembly for wafer cleaning according to claim 2, wherein the front end is provided with water outlet holes near the edge of the step structure and/or the surface of the step structure.

4. The roll brush assembly for wafer cleaning according to claim 3, wherein at least a portion of the water outlet is formed as an inclined hole forming an angle of 30-75 ° with the circumference of the main body.

5. The roll brush assembly for wafer cleaning according to any one of claims 2 to 4, wherein the front end is detachably provided with a tensioning clasp for clamping the inner core into the roller.

6. The roller brush assembly for wafer cleaning of claim 5, wherein the tension clasp comprises a distal base and a plurality of fingers extending perpendicularly along a surface of the base, the fingers expanding outwardly while engaging the inner core by the elastic force of the material thereof.

7. The roller brush assembly for wafer cleaning of claim 2, wherein the outer diameter of the rear end is greater than the outer diameter of the main body such that an annular step surface is formed between the rear end and the main body;

8. The roll brush assembly for wafer cleaning of claim 7, wherein the surface of the rear end is circumferentially configured with a plurality of drain holes.

9. The roll brush assembly for wafer cleaning according to claim 7, wherein an annular groove is formed in an inner peripheral surface of an end portion of the rear end, and the inner core is drawn out of the roll by fitting a loading and unloading tool to the annular groove.

10. The roll brush assembly for wafer cleaning of claim 1, wherein a gap is left between an outer peripheral surface of the inner core and an inner peripheral surface of the roll.