Wafer cleaning device

Abstract

The invention relates to a wafer cleaning device which comprises a cleaning cup, a wafer bearing mechanism arranged in the cleaning cup and a liquid supply mechanism for providing cleaning liquid, a fluid channel is arranged in the cup wall of the cleaning cup, a plurality of holes are formed in the inner wall of the cleaning cup, all the holes are communicated with the fluid channel, and the fluid channel is communicated with the cleaning cup. All the holes are at least distributed in the top of the cleaning cup along the circumferential gap of the cleaning cup; the cleaning cup further comprises a fluid supply assembly, and the fluid supply assembly is communicated with the fluid channel through a pipeline and used for supplying fluid into the fluid channel to enable the fluid to flow out of the holes, so that the fluid is dispersed along the inner wall of the cleaning cup. According to the invention, crystallization of the inner wall of the cleaning cup can be avoided, and the processing liquid is prevented from splashing back to the surface of the wafer to affect the wafer quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a wafer cleaning device. BACKGROUND

[0002] In the process of semiconductor manufacturing, such as chemical mechanical polishing (CMP) process, a large amount of particles, grinding debris and other chemical contaminants will be left on the wafer surface. In order to remove these residues, cleaning must be carried out immediately after CMP. Among them, the wet cleaning machine as one of the mainstream cleaning equipment is widely used in this process.

[0003] The wet cleaning machine mainly includes a tank cleaning device and a single wafer cleaning device. Among them, the single wafer cleaning device is suitable for processing a single wafer at a time, mainly including a rotating chuck horizontally holding and rotating the wafer, a nozzle supplying the processing liquid to the wafer surface, and a processing cup containing the rotating chuck. In the wafer rotating cleaning process, the processing liquid is thrown out to the inner wall of the processing cup, causing crystalline particles on the inner wall of the processing cup, and in the process engineering, the processing liquid inevitably rebounds and splashes after contacting the inner wall of the processing cup, which is easy to appear the back splash phenomenon, and forms the back splash pattern defect on the wafer surface.

[0004] Therefore, a wafer cleaning device is needed to prevent crystallization and back splash. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a wafer cleaning device which can avoid the crystallization of the inner wall of the cleaning cup, prevent the processing liquid from splashing onto the wafer surface, and affect the wafer quality.

[0006] According to a first aspect of the embodiments of the present application, a wafer cleaning device is provided, comprising: a cleaning cup, a wafer bearing mechanism placed in the cleaning cup, and a liquid supply mechanism for providing cleaning liquid, a fluid passage is arranged in the cup wall of the cleaning cup, a plurality of holes are arranged on the inner wall of the cleaning cup, all the holes are communicated with the fluid passage, and all the holes are distributed on the top of the cleaning cup at least along the circumferential gap of the cleaning cup. Further comprising a fluid supply assembly, the fluid supply assembly is communicated with the fluid passage through a pipeline, for supplying fluid into the fluid passage to make the fluid flow out of each hole, so that the fluid is dispersed along the inner wall of the cleaning cup.

[0007] In an embodiment, in the depth direction of the cleaning cup, the inner wall of the cleaning cup is provided with multiple rings of holes, and each ring is provided with multiple holes.

[0008] In one embodiment, in the depth direction of the cleaning cup, the holes constituting the topmost circle are located at a predetermined distance from the top edge of the cleaning cup, and the holes constituting the bottommost circle are located on the first cross section of the cleaning cup, which is flush with the plane of the surface of the wafer carrier mechanism that carries the wafer.

[0009] In one embodiment, in the depth direction of the cleaning cup, the holes constituting the topmost circle are located at a predetermined distance from the top edge of the cleaning cup, and the holes constituting the bottommost circle are located on the second cross section of the cleaning cup, which is located at a predetermined distance below the plane of the surface of the wafer carrier mechanism that carries the wafer.

[0010] In one embodiment, the holes of different circles are staggered in the holes of adjacent circles.

[0011] In one embodiment, the fluid supply assembly comprises a deionized water supply and / or a gas supply.

[0012] In one embodiment, the cup wall of the cleaning cup is provided with a gas channel, and the top edge of the cleaning cup is provided with at least one circle of gas holes distributed in a ring shape, all the gas holes being connected to the gas channel, and each gas hole being located above the holes.

[0013] In one embodiment, the spray center line of the gas hole forms an acute angle with the inner wall of the cleaning cup.

[0014] In one embodiment, in the circumferential direction of the cleaning cup, the gap between adjacent gas holes is greater than the gap between adjacent holes.

[0015] In one embodiment, the gas channel is connected to a nitrogen source through a pipeline.

[0016] Compared with the prior art, the application has the following beneficial effects: By providing a fluid channel in the cup wall of the cleaning cup and distributing a plurality of holes on the inner wall, the fluid supply assembly supplies fluid into the fluid channel so that the fluid flows out of each hole. In this way, when the fluid is a liquid, a layer of flowing water film can be formed on the inner wall surface of the cleaning cup. The water film can contact the cleaning liquid thrown out by the wafer rotation during the wafer cleaning process, so as to carry the cleaning liquid to the bottom of the cleaning cup and then be collected, thereby avoiding crystallization or back splash of the cleaning liquid on the inner wall of the cleaning cup. In addition, when the fluid is a gas, the inner wall surface of the cleaning cup can be purged, which can clean and dry the inner wall surface of the cleaning cup, further avoiding the occurrence of crystallization and other pollution particles on the inner wall of the cleaning cup. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1This is a schematic diagram of a single-wafer cleaning equipment; Figure 2 This is a partial cross-sectional schematic diagram of a cleaning cup according to an exemplary embodiment; Figure 3 This is a schematic diagram showing the unfolded inner wall surface of a cleaning cup according to an exemplary embodiment; Figure 4 This is a schematic diagram showing the unfolded inner wall surface of a cleaning cup according to another exemplary embodiment.

[0018] In the picture, 1. Single-wafer cleaning equipment; 11. Cleaning cup; 12. Nozzle; 13. Rotary chuck; 101, Cup wall; 102, Hole; 102a, Top hole; 102b, Bottom hole; 103, Fluid channel; 104, gas passage; 105, pore. Detailed Implementation

[0019] Unless otherwise defined, the technical or scientific terms used in this specification and claims shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. Specific embodiments of this application will be described below in conjunction with the accompanying drawings. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. Without departing from the spirit and scope of this application, those skilled in the art can modify and substitute the embodiments of this application, and the resulting embodiments are also within the protection scope of this application.

[0020] like Figure 1 As shown, the single-wafer cleaning equipment 1 mainly includes a rotating chuck 13 that horizontally holds and rotates the wafer, a nozzle 12 that supplies the cleaning solution to the wafer surface, and a cleaning cup 11 that houses the rotating chuck 13. The wafer W is placed on the rotating chuck 13. During the cleaning process, the nozzle 12 sprays the cleaning solution onto the wafer surface. Accompanied by the high-speed rotation of the rotating chuck 13, the cleaning of the wafer W is completed. As the wafer W and the rotating chuck 13 rotate, the cleaning solution is thrown against the inner wall of the cleaning cup 11 by centrifugal force. Figure 1 The arrows indicate the direction in which the cleaning solution is ejected, which causes the inner wall of the cleaning cup 11 to easily crystallize, and the cleaning solution will splash back onto the wafer surface, affecting the wafer quality.

[0021] To address the aforementioned technical problems, this application provides a wafer cleaning apparatus, which can be a single-wafer cleaning device 1, preventing crystallization on the inner wall of the cleaning cup and preventing backsplashing of the cleaning solution. (Reference) Figure 2In one specific embodiment, it includes: a cleaning cup 11, a wafer carrier mechanism (not shown) placed inside the cleaning cup 11, and a liquid supply mechanism (not shown) for providing cleaning fluid. The cleaning cup 11 has a fluid channel 103 in its cup wall 101, and a plurality of holes 102 on its inner wall. All holes 102 are connected to the fluid channel 103, and all holes 102 are distributed at least along the circumferential gap at the top of the cleaning cup 11, that is, at least one ring of holes 102 is provided at the top of the cleaning cup 11 (such as the opening for the wafer to enter the cleaning cup). It also includes a fluid supply assembly 14, which is connected to the fluid channel 103 through a pipeline for supplying fluid into the fluid channel 103 so that the fluid flows out from each hole 102 and is dispersed along the inner wall of the cleaning cup 11.

[0022] In this embodiment, a fluid channel 103 is provided in the wall 101 of the cleaning cup, and multiple holes 102 are distributed on the inner wall. The fluid supply component 14 supplies fluid into the fluid channel, causing the fluid to flow out from each hole 102. Thus, when the fluid is liquid, a flowing water film can be formed on the inner wall surface of the cleaning cup. Figure 3 As shown, when deionized water (DIW) is supplied into the fluid channel 103, the deionized water flows downwards along the inner wall. Due to the numerous pores that can be densely distributed across the entire inner wall surface, and the small size of the pores, a water mist can be formed on the inner wall surface, creating a flowing water film. This water film can contact the cleaning fluid ejected by the rotating wafer during the wafer cleaning process, thus carrying the cleaning fluid to the bottom of the cleaning cup for collection. This prevents the cleaning fluid from crystallizing or splashing back onto the inner wall of the cleaning cup. Additionally, when the fluid is a gas, see... Figure 3 As shown, nitrogen (N2) or dry air is supplied into the fluid channel 103, which can be sprayed out from each hole 102 to blow clean the inner wall of the cleaning cup, thereby cleaning and drying the inner wall of the cleaning cup and further preventing the formation of contaminant particles such as crystals on the inner wall of the cleaning cup.

[0023] In one embodiment, in the depth direction of the cleaning cup, see Figure 3 and Figure 4 The diagrams shown are schematic representations of the inner wall of the cleaning cup. The inner wall of the cleaning cup has multiple rings of holes 102, with multiple holes 102 within the gaps of each ring. In this embodiment, the holes 102 are arranged in an array, making them densely distributed on the inner wall. This ensures that the deionized water sprayed from each hole is evenly atomized and distributed on the inner wall surface of the cleaning cup, avoiding the formation of water droplets and ensuring the uniformity of the water film. Specifically, all holes 102 on the inner wall of the cleaning cup satisfy the following conditions: the gap between adjacent rings and the gap between adjacent holes within each ring are both 1mm-5mm; or, there are no gaps between adjacent rings, and the gap between adjacent holes within each ring is 0.5mm-3mm.

[0024] In the depth direction of the cleaning cup, see Figure 4 As shown, the topmost hole (i.e., top hole 102a) among all the holes 102 is located at a predetermined distance from the top edge of the cleaning cup, and the bottommost hole (i.e., bottom hole 102b) among all the holes is located on the first cross-section of the cleaning cup, which is flush with the plane of the wafer-bearing surface in the wafer carrier mechanism. In this embodiment, the wafer carrier mechanism can be... Figure 1 The rotating chuck 13 is used to horizontally hold and rotate the wafer. During the wafer cleaning process, as the rotating chuck 13 rotates at high speed, the cleaning fluid is thrown out from the center of the wafer by centrifugal force. After radial flow, edge detachment, and atomization, it impacts the inner wall of the cleaning cup along a parabolic trajectory, forming upper and lower boundaries on the inner wall of the cleaning cup. The upper boundary is the area of ​​droplet impact that is furthest from the projection of the wafer rotation plane on the inner wall of the cleaning cup (i.e., flush with the plane supporting the wafer in the wafer carrier mechanism) and can still be effectively counted. The lower boundary is the area of ​​droplet impact that is furthest from the wafer rotation plane projected onto the inner wall of the cleaning cup. The projection of the surface onto the inner wall of the cleaning cup is onto the area where a continuous liquid film or high-density droplet impact begins to appear. In this embodiment, the holes 102 are distributed between the upper and lower boundaries of the inner wall. That is, the topmost hole (i.e., top hole 102a) can be located on the inner wall at a position higher than or equal to the upper boundary, and the bottommost hole (i.e., bottom hole 102b) can be located on the inner wall at a position lower than or equal to the lower boundary. This further ensures that the cleaning liquid directly contacts the water film on the inner wall, so as to carry the cleaning liquid to the bottom of the cleaning cup and be collected, avoiding back splashing of the cleaning liquid or adhesion and crystallization on the inner wall.

[0025] Specifically, in the depth direction of the cleaning cup, the topmost ring of all the holes 102 is located at a predetermined distance from the top edge of the cleaning cup, and the bottommost ring of all the holes is located on the second cross-section of the cleaning cup, which is located at a predetermined distance below the plane containing the wafer in the wafer carrier mechanism. In this embodiment, the bottommost ring of holes is set below the lower boundary of the inner wall. For example, holes are also provided on the cup wall near its bottom edge, thereby increasing the distribution of holes to make the inner wall of the cleaning cup cleaner and avoid crystallization.

[0026] To better form a water film on the inner wall of the cleaning cup, the holes in adjacent rings are staggered to avoid linear water flow, which would affect the formation of the water film on the inner wall of the cleaning cup.

[0027] Specifically, the fluid supply components include a deionized water supply unit and / or a gas supply unit. The gas supply unit can supply dry air or nitrogen (N2) to purge the inner wall of the cleaning cup, thereby cleaning the cleaning cup during process intervals and further preventing the cleaning liquid from adhering to the inner wall of the cleaning cup and generating crystal particles.

[0028] In one implementation, see Figure 2 and Figure 3 As shown, the cleaning cup 11 has a gas channel 104 in its cup wall 101, and at least one ring of circumferentially distributed air holes 105 at the top edge of the cleaning cup 11. All air holes 105 are connected to the gas channel, and each air hole 105 is located above the hole 102. The gas ejected from the air holes 105 can form an air curtain above the hole 102, suppressing the upward splashing of cleaning liquid. At the same time, the flow direction of the water film formed by the water mist ejected from each hole 102 can be adjusted, so that the water film flows evenly downward along the inner wall of the cleaning cup. That is, a double-layer interface of air film and water film is formed at the top edge of the cleaning cup to prevent the back splashing of cleaning liquid. In addition, during the process interval, dry gas can be ejected through the air holes to clean the cleaning cup, further preventing the cleaning liquid from adhering to the inner wall of the cleaning cup and forming crystal particles. Dry air or nitrogen (N2) can be transported in the gas channel 104. The gas channel 104 can be connected to a nitrogen source through a pipeline. A control valve for adjusting the gas flow rate is installed on the pipeline to adjust the gas ejection volume according to process requirements.

[0029] Specifically, the spray center line of the vent 105 forms an acute angle with the inner wall of the cleaning cup 11, meaning the vent 105 sprays gas diagonally downwards, making the gas path closer to the inner wall surface of the cleaning cup 11 to improve the cleaning effect and evenly disperse the water film. The angle between the spray center line of the vent 105 and the inner wall of the cleaning cup 11 can be any acute angle, such as 60°, 45°, 30°, or less than 30°.

[0030] In the circumferential direction of the cleaning cup 11, the gap between adjacent air holes 105 is larger than the gap between adjacent holes 102. In this embodiment, the distribution density of holes 102 is greater than that of air holes 105, which facilitates the formation of air curtains and water films on the cleaning cup 11. In another embodiment, the diameter of the air holes 105 can be larger than the diameter of the holes 102. Specifically, the shape and size of the air holes 105 and holes 102 can be the same or different, and are not limited here.

[0031] In one embodiment, the fluid channel 103 and the gas channel 104 can be formed directly in the wall of the cleaning cup through processes such as punching. Alternatively, the wall of the cleaning cup can be a hollow structure composed of double-layer plates, with the fluid channel 103 and the gas channel 104 separated in the hollow area. To better facilitate communication between the holes and the fluid channel 103, the fluid channel 103 can be a channel located close to and circumferentially along the inner wall of the cleaning cup. The specific formation method of the fluid channel 103 and the gas channel 104 is not limited here; it only needs to achieve the purpose of transporting fluid to the holes and vents.

[0032] In one embodiment, the cleaning cup of the wafer cleaning apparatus may include multiple layers of cup walls arranged circumferentially. Some layers of the cup walls can move up and down relative to the bottom of the cleaning cup under the drive of a lifting mechanism to increase the depth of the cleaning cup. Alternatively, it can be used to collect different cleaning solutions or processing solutions for different processes. Each cup wall is provided with the fluid channel 103, holes 102, gas channel 104, and vents 105 disclosed in the above embodiments. That is, each cup wall can form a water film or a gas film-water film double-layer interface to prevent the cleaning solution or processing solution from adhering to the inner wall surface of the cleaning cup and forming crystal particles, while preventing the cleaning solution from splashing back onto the wafer surface and affecting the wafer quality.

[0033] In the wafer cleaning apparatus of the above embodiments, during the wafer cleaning process, deionized water can be supplied to the fluid channel 103 through the fluid supply component 14. The deionized water is sprayed out from each hole 102 to form a water film on the inner wall of the cleaning cup. When the cleaning liquid is thrown out by centrifugal force, it can come into contact with the water film and be collected along with the flow of the water film, avoiding direct contact between the cleaning liquid and the inner wall surface of the cleaning cup, thus preventing crystallization. At the same time, it avoids backsplashing of the cleaning liquid, which would cause contaminants to adhere to the wafer surface and affect the wafer quality. Specifically, the size and shape of each hole 102 can be set as needed and are not limited here. For example, it can be funnel-shaped, with the small diameter end close to the fluid channel 103, so that the deionized water can be atomized and sprayed out. The gas channel 104 can simultaneously supply nitrogen gas, which is sprayed out from each gas hole 105 to form an air curtain at the top edge of the cleaning cup. The gas sprayed from the gas hole 105 can be blown downwards at an angle, combining with the water film to form a gas-water double-layer interface, further ensuring the isolation between the cleaning liquid and the inner wall surface of the cleaning cup, and preventing the cleaning liquid from crystallizing and backsplashing. Specifically, the size and shape of each vent 105 can be set as needed, and are not limited here.

[0034] During the cleaning and maintenance of the wafer cleaning apparatus, dry gas, such as nitrogen, can be introduced into both the fluid channel 103 and the gas channel 104. The gas ejected from each hole 102 and the air hole 105 can blow away the inner wall surface of the cleaning cup, drying and cleaning it, and further preventing contaminant particles from appearing on the inner wall of the cleaning cup due to crystallization of the cleaning solution.

[0035] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A wafer cleaning apparatus comprising: The cleaning cup, the wafer supporting mechanism placed in the cleaning cup, and the liquid supply mechanism for supplying cleaning liquid, characterized in that a fluid passage is arranged in the cup wall of the cleaning cup, and a plurality of holes are arranged on the inner wall of the cleaning cup, all the holes being communicated with the fluid passage and being distributed on the top of the cleaning cup at least along the circumferential gap of the cleaning cup. The fluid supply assembly is further included, which is communicated with the fluid passage through a pipeline for supplying fluid into the fluid passage to make the fluid flow out of the holes so that the fluid is dispersed along the inner wall of the cleaning cup.

2. The wafer cleaning apparatus of claim 1, wherein In the depth direction of the cleaning cup, the inner wall of the cleaning cup is provided with a plurality of circles of holes, and each circle is provided with a plurality of holes.

3. The wafer cleaning apparatus of claim 2, wherein In the depth direction of the cleaning cup, the holes constituting the topmost circle among all the holes are located at a preset distance from the top edge of the cleaning cup, and the holes constituting the bottommost circle among all the holes are located on the first cross section of the cleaning cup, which is flush with the plane where the surface of the wafer supporting mechanism for supporting the wafer is located.

4. The wafer cleaning apparatus as claimed in claim 2, wherein In the depth direction of the cleaning cup, the holes constituting the topmost circle among all the holes are located at a preset distance from the top edge of the cleaning cup, and the holes constituting the bottommost circle among all the holes are located on the second cross section of the cleaning cup, which is located at a preset distance below the plane where the surface of the wafer supporting mechanism for supporting the wafer is located.

5. The wafer cleaning apparatus as claimed in claim 2, wherein Among the holes located in adjacent circles, the holes of different circles are distributed in a staggered manner.

6. The wafer cleaning apparatus according to any one of claims 1 to 5, wherein The fluid supply assembly includes a deionized water supply and / or a gas supply.

7. The wafer cleaning apparatus according to any one of claims 1 to 5, wherein A gas passage is arranged in the cup wall of the cleaning cup, and at least one circle of gas holes is arranged on the top edge of the cleaning cup in a circumferential distribution, all the gas holes being communicated with the gas passage, and each gas hole being located above the hole.

8. The wafer cleaning apparatus of claim 7, wherein The jet center line of the gas hole forms an acute angle with the inner wall of the cleaning cup.

9. The wafer cleaning apparatus as claimed in claim 7, wherein In the circumferential direction of the cleaning cup, the gap between adjacent gas holes is greater than the gap between adjacent holes.

10. The wafer cleaning apparatus as claimed in claim 9, wherein The gas passage is connected with a nitrogen source through a pipeline.

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