Wafer drying apparatus and method

Abstract

The application provides a wafer drying device and method, the wafer drying device includes: a wafer bearing table for fixing and driving the wafer to rotate; a drying medium supply module for supplying drying medium to the surface of the wafer; the drying medium supply module includes a spray head for spraying drying medium, and a movement unit for controlling the movement of the spray head above the wafer; a control module connected to the wafer bearing table and the drying medium supply module for controlling the rotation speed of the wafer, the supply flow of the drying medium and the moving speed of the spray head, so that the direction of the drying liquid flying away from the wafer is oblique to the tangent of the wafer. The application reduces the rotation speed of the wafer, the supply flow of the drying medium and the moving speed of the spray head when drying the edge of the wafer, so that the drying liquid flies away from the wafer in the oblique direction to the tangent of the wafer, the reverse backflow effect of the liquid at the edge of the wafer is inhibited, the drying effect at the edge of the wafer is improved, the defects such as water marks caused by insufficient drying are reduced, and the product yield is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a wafer drying apparatus and method. Background Technology

[0002] As semiconductor process linewidths continue to shrink while wafer sizes continue to increase, traditional tank-type wet processing can no longer meet the requirements of advanced processes. Monolithic wet processing, with its excellent particle removal capability, uniformity, and controllability, provides a stable and controllable wet process solution for advanced processes of 5nm and above.

[0003] Currently, IPA (isopropyl alcohol) is mainly used for wafer drying after single-wafer wet processing. During IPA drying, IPA is sprayed onto the surface of a high-speed rotating wafer, and nitrogen purging is used to remove residual moisture from the wafer surface. However, in existing single-wafer wet processing machines, mechanical clamps are generally used to hold the wafer. The clamping area at the wafer edge can obstruct the outward flow of liquids such as IPA, and may even cause backflow and splashing. This severely affects the drying effect and uniformity at the wafer edge. The area near the clamp is more prone to defects such as water marks due to insufficient drying, causing fluctuations in wet processing capabilities and ultimately leading to a decrease in product yield.

[0004] Therefore, it is necessary to propose a new wafer drying device and method to solve the above problems. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a wafer drying apparatus and method to solve the problem of poor uniformity of wafer edge drying in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides a wafer drying apparatus, characterized in that it comprises:

[0007] A wafer carrier stage is used to fix and rotate a wafer, the wafer including a central region and an edge region located around the central region;

[0008] A drying medium supply module is used to supply a drying medium to the surface of the wafer, the drying medium comprising at least a drying liquid; the drying medium supply module includes a nozzle for spraying the drying medium and a motion unit for controlling the movement of the nozzle above the wafer.

[0009] The control module, connected to the wafer carrier stage and the drying medium supply module, is used to control the rotational speed of the wafer, the supply flow rate of the drying medium, and the moving speed of the nozzle, so that the direction in which the drying liquid flies away from the wafer is oblique to the tangent of the wafer.

[0010] As an optional embodiment of the present invention, the drying medium further includes a drying gas; the drying medium supply module includes a drying liquid nozzle for spraying the drying liquid and a drying gas nozzle for spraying the drying gas.

[0011] As an optional embodiment of the present invention, the arrangement direction of the drying liquid nozzle and the drying gas nozzle is parallel to the moving direction of the drying liquid nozzle and the drying gas nozzle, and the drying gas nozzle is located behind the drying liquid nozzle when moving along the moving direction.

[0012] As an optional embodiment of the present invention, there are multiple drying gas nozzles, and the arrangement direction of the multiple drying gas nozzles is perpendicular to the moving direction of the drying liquid nozzle and the drying gas nozzle.

[0013] As an optional embodiment of the present invention, the drying liquid nozzle includes a first drying liquid nozzle and a second drying liquid nozzle, wherein the flow rate of the drying liquid supplied by the first drying liquid nozzle is greater than the flow rate of the drying liquid supplied by the second drying liquid nozzle.

[0014] As an optional embodiment of the present invention, the drying medium supply module further includes a drying gas source, a drying liquid source, a drying gas pipeline, and a drying liquid pipeline; the drying gas pipeline connects the drying gas source and the drying gas nozzle, and the drying liquid pipeline connects the drying liquid source and the drying liquid nozzle.

[0015] As an optional embodiment of the present invention, the control module includes a drying gas flow control unit and a drying liquid flow control unit; the drying gas flow control unit is disposed on the drying gas pipeline and is used to control the supply flow rate of the drying gas; the drying liquid flow control unit is disposed on the drying liquid pipeline and is used to control the supply flow rate of the drying liquid.

[0016] As an alternative to the present invention, the drying liquid includes isopropanol, and the drying gas includes nitrogen.

[0017] As an optional embodiment of the present invention, the motion unit includes a robotic arm for mounting the nozzle and a swing motor for controlling the robotic arm to swing in a horizontal plane.

[0018] As an optional embodiment of the present invention, the motion unit further includes a lifting motor for raising and lowering the robotic arm in the vertical direction.

[0019] As an optional embodiment of the present invention, the control module further includes a robotic arm control unit for controlling the movement of the robotic arm, the robotic arm control unit being connected to the swing motor and the lifting motor.

[0020] As an optional embodiment of the present invention, the control module includes a speed control unit for controlling the rotational speed of the wafer, and the wafer carrier includes a rotary motor for driving the wafer carrier to rotate, and the speed control unit is connected to the rotary motor.

[0021] As an optional embodiment of the present invention, at least one of the three factors—the rotational speed of the wafer, the supply flow rate of the drying liquid, and the moving speed of the nozzle—is less than the value when the nozzle is located in the edge region of the wafer when it is located in the center region of the wafer.

[0022] As an optional embodiment of the present invention, when the nozzle is located in the edge region of the wafer, the rotational speed of the wafer is less than when the nozzle is located in the center region of the wafer; when the nozzle is located in the edge region of the wafer, the supply flow rate of the drying liquid is less than when the nozzle is located in the center region of the wafer; and when the nozzle is located in the edge region of the wafer, the moving speed of the nozzle is less than when the nozzle is located in the center region of the wafer.

[0023] The present invention also provides a method of using a wafer drying apparatus, comprising the following steps:

[0024] A wafer carrier stage is provided to fix a wafer on the wafer carrier stage, and the wafer carrier stage drives the wafer to rotate; the wafer includes a central region and an edge region located around the central region;

[0025] A drying medium, comprising at least a drying liquid, is sprayed onto the surface of the wafer through a nozzle. During the spraying process, the nozzle moves from the center region of the wafer to the edge region of the wafer, and the rotational speed of the wafer, the supply flow rate of the drying medium, or the moving speed of the nozzle is controlled so that the direction in which the drying liquid leaves the wafer is oblique to the tangent of the wafer.

[0026] As an optional embodiment of the present invention, at least one of the three factors—the rotational speed of the wafer, the supply flow rate of the drying liquid, and the moving speed of the nozzle—is less than the value when the nozzle is located in the edge region of the wafer when it is located in the center region of the wafer.

[0027] As an optional embodiment of the present invention, when the nozzle is located in the edge region of the wafer, the rotational speed of the wafer is less than when the nozzle is located in the center region of the wafer; when the nozzle is located in the edge region of the wafer, the supply flow rate of the drying liquid is less than when the nozzle is located in the center region of the wafer; and when the nozzle is located in the edge region of the wafer, the moving speed of the nozzle is less than when the nozzle is located in the center region of the wafer.

[0028] As an optional embodiment of the present invention, when the nozzle is located in the edge region of the wafer, the rotational speed of the wafer, the supply flow rate of the drying liquid, and the moving speed of the nozzle all gradually decrease during the process of the nozzle moving towards the edge of the wafer.

[0029] As an optional embodiment of the present invention, the drying medium further includes a drying gas, and the nozzle includes a drying liquid nozzle for spraying the drying liquid and a drying gas nozzle for spraying the drying gas, wherein the drying gas nozzle is located behind the drying liquid nozzle when moving in the moving direction.

[0030] As an optional embodiment of the present invention, there are multiple drying gas nozzles, and the arrangement direction of the multiple drying gas nozzles is perpendicular to the moving direction of the drying liquid nozzle and the drying gas nozzle.

[0031] As an optional embodiment of the present invention, the drying liquid nozzle includes a first drying liquid nozzle and a second drying liquid nozzle, wherein the flow rate of the drying liquid supplied by the first drying liquid nozzle is greater than the flow rate of the drying liquid supplied by the second drying liquid nozzle.

[0032] As an alternative embodiment of the present invention, the drying liquid is sprayed simultaneously using both the first drying liquid nozzle and the second drying liquid nozzle at the junction of the central region and the edge region of the wafer.

[0033] As described above, the present invention provides a wafer drying apparatus and method, which have the following beneficial effects:

[0034] This invention introduces a novel wafer drying apparatus and method. During the wafer drying process, by reducing parameters such as wafer rotation speed, drying medium supply flow rate, and nozzle movement speed during wafer edge drying, the drying liquid is made to fly away from the wafer from a direction oblique to the wafer tangent. This suppresses the reverse backflow effect of liquid at the wafer edge, improves the drying effect at the wafer edge, reduces defects such as watermarks caused by insufficient drying, and improves product yield. Attached Figure Description

[0035] Figure 1The image shown is a front cross-sectional view of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0036] Figure 2 The illustration shows a wafer drying apparatus provided in Embodiment 1 of the present invention. Figure 1 Side view section in direction A.

[0037] Figure 3 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0038] Figure 4 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0039] Figure 5 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0040] Figure 6 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0041] Figure 7 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0042] Figure 8 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0043] Figure 9 The diagram shown is an enlarged schematic of the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention, showing the process up to the edge region of the wafer.

[0044] Figure 10 The diagram shows the change in the supply flow rate of the drying medium from the center region of the wafer to the edge region of the wafer during the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0045] Figure 11 The diagram shows the rotational speed change from the center region of the wafer to the edge region during the drying process of a wafer drying apparatus provided in Embodiment 1 of the present invention.

[0046] Figure 12 The diagram shows the relationship between the drying medium flow rate, the mechanical fixture size, and the edge removal distance after wafer drying in a wafer drying apparatus provided in Embodiment 1 of the present invention; wherein curve a is the curve showing the relationship between IPA flow rate and edge removal distance under the clamping of type A mechanical fixture; curve b is the curve showing the relationship between IPA flow rate and edge removal distance under the clamping of type B mechanical fixture.

[0047] Figure 13 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 2 of the present invention.

[0048] Figure 14 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 2 of the present invention.

[0049] Figure 15 The image shown is a top view of the drying process of a wafer drying apparatus provided in Embodiment 2 of the present invention.

[0050] Figure 16 The diagram shown is an enlarged view of the drying process of a wafer drying apparatus provided in Embodiment 2 of the present invention, showing the process up to the edge region of the wafer.

[0051] Figure 17 The image shown is a side cross-sectional view of a wafer drying apparatus provided in Embodiment 3 of the present invention during the drying process.

[0052] Figure 18 The image shown is a side cross-sectional view of a wafer drying apparatus provided in Embodiment 3 of the present invention during the drying process.

[0053] Component designation explanation

[0054] 101 wafer

[0055] 102 Drying medium

[0056] 102a Dry liquid

[0057] 102b Dry Gas

[0058] 11 Wafer carrier stage

[0059] 111 Rotary Electric Machine

[0060] 112 Protective Case

[0061] 113 Mechanical clamps

[0062] 114 Vacuum Adsorption Device

[0063] 12 Drying medium supply module

[0064] 121 nozzle

[0065] 121a Drying Liquid Nozzle

[0066] 121b Dry Gas Nozzle

[0067] 122 motion units

[0068] 122a robotic arm

[0069] 122b Oscillating Motor

[0070] 122c Lifting Motor

[0071] 123 Dry Gas Source

[0072] 123a Dry gas pipeline

[0073] 124 Dry liquid source

[0074] 124a Dry liquid piping

[0075] 13 Control Module

[0076] 131 Dry Gas Flow Control Unit

[0077] 132 Dry Liquid Flow Control Unit

[0078] 133 Robotic Arm Control Unit

[0079] 134 Speed ​​Control Unit

[0080] 201 wafer

[0081] 212 Protective Case

[0082] 213 Mechanical clamps

[0083] 221a Drying Liquid Nozzle

[0084] 221b Dry Gas Nozzle

[0085] 222a robotic arm

[0086] 301 wafer

[0087] 302a Dry Liquid

[0088] 302b Dry Gas

[0089] 31 Wafer Support Stage

[0090] 311 Rotary Electric Machine

[0091] 312 Protective Case

[0092] 321b Dry Gas Nozzle

[0093] 321c First Drying Liquid Nozzle

[0094] 321d Second Drying Liquid Nozzle Detailed Implementation

[0095] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0096] Please see Figures 1 to 18 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation, the shape, quantity and proportion of each component in the actual implementation can be arbitrarily changed, and the layout of the components may also be more complex.

[0097] Example 1

[0098] Please see Figures 1 to 12 This embodiment provides a wafer drying apparatus and method.

[0099] like Figure 1 and Figure 2 As shown, the wafer drying apparatus includes:

[0100] A wafer carrier stage 11 is used to fix and drive the wafer 101 to rotate. The wafer 101 includes a central region and an edge region located around the central region.

[0101] A drying medium supply module 12 is used to supply a drying medium 102 to the surface of the wafer 101, the drying medium including at least a drying liquid 102a; the drying medium supply module includes a nozzle 121 for spraying the drying medium 102, and a motion unit 122 for controlling the movement of the nozzle 121 above the wafer 101.

[0102] The control module 13 is connected to the wafer carrier stage 11 and the drying medium supply module 12. It is used to control the rotation speed of the wafer 101, the supply flow rate of the drying medium and the moving speed of the nozzle 121, so that the direction in which the drying liquid flies away from the wafer 101 is oblique to the tangent of the wafer 101.

[0103] like Figure 1 The image shown is a front cross-sectional view of a wafer drying apparatus provided in this embodiment. Figure 2 yes Figure 1 A side cross-sectional view along direction A. To more clearly illustrate the nozzle structure, in... Figure 2 The drying medium supply module 12 and the control module 13, excluding the nozzle, are omitted. Figures 3 to 8This is a top view of the wafer drying apparatus during operation.

[0104] exist Figure 1 In this process, the wafer 101 is fixed on the wafer carrier stage 11. Optionally, the wafer 101 can be fixed by a vacuum adsorption device, a mechanical clamp, or a combination of both. The nozzle 121 is used to spray the drying medium 102 onto the surface of the wafer 101. By spraying the drying medium 102 in conjunction with the high-speed rotation of the wafer 101, residual moisture on the surface of the wafer 101 is removed. A protective shell 112 is also provided around the wafer carrier stage 11 to prevent liquid splashing caused by wafer rotation during operation. Figure 1 and Figure 3 As shown, in this embodiment, in addition to using a vacuum adsorption device 114 to adsorb and fix the wafer 101, a mechanical clamp 113 is also used to clamp and fix the wafer 101 from the edge. Due to the cross-sectional selection, the mechanical clamp 113... Figure 1 The cross-sectional view is not shown.

[0105] As an example, such as Figure 2 As shown, the drying medium 102 further includes a drying gas 102b; the drying medium supply module 12 includes a drying liquid nozzle 121a for spraying the drying liquid 102a and a drying gas nozzle 121b for spraying the drying gas 102b. Optionally, the drying liquid 102a includes isopropanol (IPA), and the drying gas 102b includes nitrogen. The nitrogen can be heated high-temperature nitrogen to improve the drying capacity of the drying gas 102b. In this embodiment, by introducing IPA as the drying liquid 102a, residual moisture on the surface of the wafer 101 is adsorbed. Under the high-speed rotation of the wafer 101, the IPA adsorbed with moisture moves towards the outer edge of the wafer 101 under the action of centrifugal force, and finally throws out of the wafer 101 with moisture; at the same time, through the purging of high-temperature nitrogen, the IPA adsorbed with moisture will also evaporate and carry away the moisture. The combination of the above two mechanisms is the basic principle of single-wafer wet IPA drying. It should be noted that the drying medium 102 can also be other liquid or gaseous media that can adsorb and remove moisture. For example, other hydrophilic and volatile organic solvents such as ethanol can be used instead of IPA, and inert gases such as argon that do not readily react chemically with the wafer can be used instead of nitrogen. In other embodiments of the present invention, only a drying liquid or only a drying gas can be used as the drying medium to dry the wafer 101, which does not affect the concept of the present invention.

[0106] As an example, such as Figures 1 to 3As shown, the arrangement direction of the drying liquid nozzle 121a and the drying gas nozzle 121b is parallel to the moving direction of the drying liquid nozzle 121a and the drying gas nozzle 121b. When the drying gas nozzle 121b moves along the moving direction, it is located behind the drying liquid nozzle 121a. During the IPA drying process, the nozzle 121, including the drying liquid nozzle 121a and the drying gas nozzle 121b, moves along... Figure 3 The direction indicated by the dashed arrow is from the center of the wafer 101 towards the edge. During this movement, the drying gas nozzle 121b is positioned behind the drying liquid nozzle 121a. This allows hot nitrogen gas to purge any residual IPA liquid along the movement path, ensuring that no liquid residue remains on the path of the nozzle 121. Figures 3 to 5 As shown, the light-colored area on the wafer 101 is the dried area, and the dark-colored area is the undried area. The nozzle 121 moves in the direction shown by the dotted arrow, and in conjunction with the rotation of the wafer 101, the moisture on the surface of the wafer 101 is gradually dried from the center to the edge.

[0107] As an example, such as Figure 1 As shown, the drying medium supply module 12 further includes a drying gas source 123, a drying liquid source 124, a drying gas pipeline 123a, and a drying liquid pipeline 124a. The drying gas pipeline 123a connects the drying gas source 123 and the drying gas nozzle 121b, and the drying liquid pipeline 124a connects the drying liquid source 124 and the drying liquid nozzle 121a. Optionally, the drying gas source 123 includes a nitrogen source and a nitrogen heating device to supply high-temperature nitrogen, and the drying liquid source 124 includes an IPA source, each connected to a corresponding nozzle via a pipeline to supply the corresponding drying medium to the surface of the wafer 101.

[0108] As an example, such as Figure 1 As shown, the control module 13 includes a drying gas flow control unit 131 and a drying liquid flow control unit 132. The drying gas flow control unit 131 is disposed on the drying gas pipeline 123a and is used to control the supply flow rate of the drying gas 102b. The drying liquid flow control unit 132 is disposed on the drying liquid pipeline 124a and is used to control the supply flow rate of the drying liquid 102a. Optionally, both the drying gas flow control unit 131 and the drying liquid flow control unit 132 can be mass flow controllers (MFCs) to precisely control the supply flow rate of the drying gas or drying liquid during the drying process. For example, the supply flow rate range of IPA is 0–200 mL / min, and the supply flow rate range of nitrogen is 0–100 L / min.

[0109] As an example, such as Figure 1 and Figure 3 As shown, the motion unit 122 includes a robotic arm 122a for mounting the nozzle, and a swing motor 122b for controlling the swing of the robotic arm 122a in a horizontal plane. Optionally, the motion unit 122 further includes a lifting motor 122c for raising and lowering the robotic arm 122a in the vertical direction. By introducing the swing motor 122b, the robotic arm 122a can be swinged in a horizontal plane, allowing the nozzle 121 to move along... Figure 3 The direction indicated by the dashed arrow is from the center of the wafer 101 to the edge. The lifting motor 122c can also control the robotic arm 122a to move vertically, so as to precisely control the nozzle 121 to maintain a suitable working distance from the surface of the wafer 101.

[0110] As an example, such as Figure 1 As shown, the control module 13 further includes a robotic arm control unit 133 for controlling the movement of the robotic arm 122a. The robotic arm control unit 133 is connected to the swing motor 122b and the lifting motor 122c. In this embodiment, the robotic arm control unit 133 is also introduced, connected to the swing motor 122b and the lifting motor 122c, for controlling the robotic arm 122a to swing in the horizontal plane or to rise and fall in the vertical direction.

[0111] As an example, such as Figure 1 As shown, the control module 13 includes a speed control unit 134 for controlling the rotational speed of the wafer 101, and the wafer carrier stage 11 includes a rotary motor 111 for driving the wafer carrier stage 11 to rotate. The speed control unit 134 is connected to the rotary motor 111. In this embodiment, the rotation of the wafer 101 during operation is achieved by rotating the wafer carrier stage 11. The wafer carrier stage 11 is driven to rotate by the rotary motor 111, and the rotational speed of the wafer carrier stage 11 is controlled by the speed control unit 134.

[0112] As an example, the wafer drying device is integrated into a wet etching machine for drying wafers that have undergone wet etching. Optionally, the robotic arm 122a may also be equipped with wet etching solution pipelines and corresponding wet etching solution nozzles for spraying wet etching solution onto the surface of the wafer 101. For example, for silicon dioxide wet etching, HF solution can be used as the wet etching solution to etch silicon dioxide. The robotic arm 122a may also be equipped with deionized water pipelines and corresponding deionized water nozzles to clean the surface of the wafer 101 after wet etching. After the above etching and cleaning processes are completed, the wafer drying device provided by this invention dries the surface of the wafer 101. Of course, the wafer drying device provided by this invention is not limited to integration into a wet etching machine. In other embodiments of this invention, the wafer drying device may also be an independent process module for drying any wafer to be dried.

[0113] like Figures 1 to 12 As shown, the wafer drying method provided in this embodiment includes the following steps:

[0114] A wafer carrier stage 11 is provided to fix a wafer 101 on the wafer carrier stage 11, and the wafer carrier stage 11 drives the wafer 101 to rotate; the wafer 101 includes a central region and an edge region located around the central region;

[0115] A drying medium 102, comprising at least a drying liquid 102a, is sprayed onto the surface of the wafer 101 through a nozzle 121. During the spraying process, the nozzle 121 moves from the central region of the wafer 101 to the edge region of the wafer 101, and the rotational speed of the wafer 101, the supply flow rate of the drying medium 102, or the moving speed of the nozzle 121 is controlled so that the direction in which the drying liquid 102a leaves the wafer 101 is oblique to the tangent of the wafer 101.

[0116] like Figures 1 to 8As shown, the wafer drying method provided in this embodiment uses the wafer drying apparatus described in this embodiment. The wafer support stage 11 is driven by the rotary motor 111, which drives the wafer 101 fixed on it to rotate at high speed. The nozzle 121 starts from the center region of the wafer 101 and moves continuously towards the edge region of the wafer 101 during the spraying of the drying medium 102. During the movement, the control module 13 controls and adjusts the rotational speed of the wafer 101, the supply flow rate of the drying medium 102, and the moving speed of the nozzle 121. Specifically, the rotational speed control unit 134 controls the rotational speed of the wafer 101; the drying gas flow control unit 131 and the drying liquid flow control unit 132 control the supply flow rates of the drying gas and the drying liquid; and the robotic arm control unit 133 controls the moving speed of the robotic arm 122a, i.e., the moving speed of the nozzle 121. The purpose of controlling the above parameters is primarily to reduce the non-uniformity of the drying process in the edge region of the wafer 101 when the drying process reaches that region. This non-uniformity is mainly due to the mechanical clamps hindering the outward flow of liquids such as IPA at the wafer edge, and even causing backflow. This invention improves drying uniformity by adjusting the above parameters during drying in the edge region, ensuring that the direction in which the drying liquid leaves the wafer 101 is oblique to the tangent of the wafer 101. Specifically, at least one of the following parameters—the rotational speed of the wafer 101, the supply flow rate of the drying liquid 102a, and the moving speed of the nozzle 121—is less when the nozzle 121 is located in the edge region of the wafer 101 than when it is located in the center region of the wafer 101.

[0117] like Figures 3 to 5 The diagram shown is a schematic representation of the drying process in this embodiment, starting from the central region of the wafer 101 and extending to near the edge region of the wafer 101. Figure 3 This is a schematic diagram showing the nozzle located in the central region of the wafer 101 at the beginning of the drying process. Figure 4 In this process, the central region of wafer 101 has largely completed the drying process. Figure 5 During the drying process, the drying process has approached the edge region of the wafer 101. Optionally, the edge region of the wafer 101 can be defined as a region 20 mm from the edge of the wafer 101. When approaching this region, the drying process can be considered to have entered the edge region of the wafer 101. At this time, it is necessary to control and adjust parameters such as the rotational speed of the wafer 101, the supply flow rate of the drying medium 102, and the moving speed of the nozzle 121 to suppress liquid backflow and improve drying uniformity.

[0118] like Figures 6 to 8 The diagram shown is a schematic representation of the drying process in the edge region of wafer 101 in this embodiment. Figures 6 to 8 In the process, the area of ​​the dark, undried region gradually decreases, with its width W1>W2>W3, and the width gradually decreases as the drying process progresses. Figure 6 In comparison Figure 5 The area of ​​the dark, undried region is further reduced. As an example, the width W1 of the undried region here is approximately 20 mm, which is the starting point of the wafer edge region. Figure 7 and Figure 8 In the process, the area of ​​the undried region further decreased, and the width of the undried region decreased to W2 and W3 respectively, and some areas were completely dried until... Figure 8 The drying process is basically complete.

[0119] like Figure 9 The diagram shown is an enlarged view of the edge region of the wafer 101 during the drying process. Optionally, when the nozzle 121 moves to the edge region of the wafer 101, the flow direction of the drying liquid 102a is changed by adjusting the flow rate of the drying liquid 102a from the drying liquid nozzle 121a. Figure 9 During the drying process, when the drying medium, such as IPA, is in the central region of wafer 101, the supply flow rate is relatively high. Combined with the centrifugal force generated by the wafer rotation, the drying liquid 102a is thrown out of wafer 101 from direction B, which is perpendicular to the wafer tangent direction. If there are obstacles such as clamping parts of mechanical jigs in the direction of liquid ejection, it will flow back into the wafer. When the drying process reaches the edge region of wafer 101, it will cause uneven and insufficient drying in the edge region. In this embodiment, when the drying process reaches the edge region of wafer 101, the supply flow rate of the drying medium, such as IPA, is reduced, so that the drying liquid 102a is thrown out of wafer 101 from direction C. The angle between direction C and the wafer tangent direction is greater than 0 degrees and less than 90 degrees. This will significantly reduce the backflow effect caused by the rebound of obstacles. If the supply flow rate is further reduced, the direction C in which the drying liquid 102a is thrown out of wafer 101 will get closer and closer to the wafer tangent direction A, and the backflow effect will be further weakened. Therefore, adjusting the supply flow rate to reduce the supply flow rate in the edge region of the wafer 101 is an effective means of reducing the reverse backflow effect. In this embodiment, by adjusting parameters such as the supply flow rate, wafer rotation speed, and nozzle moving speed, the drying liquid 102a is thrown out of the wafer 101 in the C direction as close as possible to the wafer tangential direction A, thereby reducing the reverse backflow effect.

[0120] It should be noted that adjusting the supply flow rate is only one way to change the flow direction of the drying liquid 102a. In this embodiment, the same effect can also be achieved by adjusting the wafer rotation speed or the nozzle moving speed.

[0121] As an example, when the nozzle 121 is located in the edge region of the wafer 101, the supply flow rate of the drying liquid 102a is less than that when the nozzle 121 is located in the center region of the wafer; when the nozzle 121 is located in the edge region of the wafer 101, the rotational speed of the wafer 101 is less than that when the nozzle 121 is located in the center region of the wafer 101; and when the nozzle 121 is located in the edge region of the wafer 101, the moving speed of the nozzle 121 is less than that when the nozzle 121 is located in the center region of the wafer 101. Optionally, when the nozzle 121 is located in the edge region of the wafer 101, the rotational speed of the wafer 101, the supply flow rate of the drying liquid 102a, and the moving speed of the nozzle 121 all gradually decrease as the nozzle 121 moves towards the edge of the wafer 101.

[0122] like Figure 10 The diagram illustrates the change in the supply flow rate of the drying medium 102 from the central region to the edge region of the wafer 101 during the drying process. As can be seen from the diagram, the supply flow rate remains balanced and stable in and around the central region of the wafer 101 during the drying process; however, as the drying process progresses to the edge region of the wafer 101, the supply flow rate gradually decreases to suppress the backflow effect generated in the edge region and improve drying uniformity. Optionally, in this embodiment, the flow rate of the IPA as the drying liquid gradually decreases from 200 mL / min in the central region to 0 mL / min at the end of the drying process in the edge region. It should be noted that... Figure 10 In this embodiment, the rate of decrease in flow rate increases as the wafer edge approaches. However, in other embodiments of the present invention, the flow rate may decrease linearly or the rate of decrease in flow rate may decrease as the wafer edge approaches.

[0123] like Figure 11The diagram illustrates the rotational speed variation of wafer 101 during the drying process, from its central region to its edge. As can be seen, during the drying process in and around the central region of wafer 101, the rotational speed remains stable. However, as the drying process progresses to the edge region, the rotational speed gradually decreases to suppress the backflow effect and improve drying uniformity. Optionally, in this embodiment, the wafer rotational speed gradually decreases from 3000 rpm in the central region to 10 rpm in the edge region. It should be noted that... Figure 11 In this invention, the rate of decrease in wafer rotation speed increases as the wafer edge approaches. However, in other embodiments of the invention, the wafer rotation speed may decrease linearly or decrease as the wafer edge approaches.

[0124] Similar to the feed rate and wafer rotation speed, the nozzle's moving speed can also be maintained within a stable range in the central region and its vicinity, gradually decreasing in the edge region to suppress the backflow effect generated in the edge region; this will not be elaborated further here. It should be noted that the three parameters—feed rate, wafer rotation speed, and nozzle moving speed—can be adjusted simultaneously or independently as needed. For example, only the feed rate can be adjusted, while the other parameters remain stable. Optionally, in this embodiment, by simultaneously adjusting the three parameters—feed rate, wafer rotation speed, and nozzle moving speed—these three parameters are maintained within a relatively high stable range in the wafer's central region and gradually decrease in the wafer's edge region.

[0125] like Figure 12 The diagram shows the relationship between the flow rate of the drying medium, such as IPA, and the size of the mechanical fixture, and the edge removal distance W of the wafer 101 after drying. The edge removal distance can be used to characterize the area of ​​uneven or insufficiently dried regions at the edge of the wafer 101 after drying. For example, for a 300mm wafer, this area is [150...]. 2 *π-(150-W) 2 *π]mm 2 .exist Figure 12 In the diagram, curve a represents the relationship between IPA flow rate and edge removal distance under the clamping of a type A mechanical fixture; curve b represents the relationship between IPA flow rate and edge removal distance under the clamping of a type B mechanical fixture. The clamping components at the wafer edge of the type A mechanical fixture are larger than those of the type B mechanical fixture. From... Figure 12As can be seen, with the same fixture, a higher IPA flow rate results in a greater edge removal distance. This is because a higher IPA flow rate leads to a more pronounced backflow effect at the wafer edge after rebounding from the clamping components, thus increasing the area of ​​uneven and insufficient drying. At the same IPA flow rate, the edge removal distance of the type A mechanical fixture is significantly greater than that of the type B mechanical fixture. This is because the clamping components of the type A mechanical fixture are larger than those of the type B mechanical fixture, resulting in a more significant backflow effect. Replacing the IPA flow rate parameter in this figure with wafer rotation speed or nozzle movement speed and collecting corresponding data yields similar curves. This also verifies the effectiveness of using a gradually decreasing IPA flow rate, wafer rotation speed, or nozzle movement speed in reducing the backflow effect at the wafer edge during the drying process in the edge region of wafer 101 compared to the central region of wafer 101. Furthermore, using a mechanical fixture with smaller clamping components also helps improve drying uniformity.

[0126] Example 2

[0127] Please see Figures 13 to 16 This embodiment provides a wafer drying apparatus and method.

[0128] like Figure 13 As shown, compared to the device provided in Embodiment 1, in this embodiment, there are multiple drying gas nozzles 221b, and the arrangement direction of the multiple drying gas nozzles 221b is perpendicular to the moving direction of the drying liquid nozzle 221a and the drying gas nozzles 221b. Compared to Embodiment 1, the method provided in this embodiment, by introducing multiple drying gas nozzles 221b, changes the flow direction of the drying liquid by adjusting the drying gas flow rate of the multiple drying gas nozzles 221b when the drying gas nozzles 221b and the drying liquid nozzles 221a move to the edge region of the wafer 201.

[0129] Similar to the device structure in Embodiment 1, in Figure 13 In the process, the wafer 201 is held and rotated by a mechanical clamp 213, and a protective shell 212 is provided around it to prevent liquid splashing caused by the wafer rotation during operation. The robotic arm 222a controls the movement of the drying liquid nozzle 221a and the drying gas nozzle 221b.

[0130] Since adjusting only three parameters—supply flow rate, wafer rotation speed, and nozzle moving speed—has limitations in changing the direction of the drying liquid ejection, the drying method provided in this embodiment increases the number of drying gas nozzles 221b to control the direction of the drying liquid ejection, thereby further suppressing the liquid backflow effect and improving drying uniformity.

[0131] like Figures 13 to 15 As shown, in this embodiment, there are two drying gas nozzles 221b, one located directly behind the moving direction of the drying liquid nozzle 221a, and the other located obliquely behind the moving direction of the drying liquid nozzle 221a. When the drying process is in the central region of the wafer 201, the drying gas is mainly supplied by the directly behind nozzle 221b. When the drying process reaches the edge region of the wafer 201, the obliquely behind nozzle 221b can be activated to effectively change the direction of liquid ejection. At this time, the directly behind nozzle 221b can be selectively turned on or off as needed. Optionally, the jet flow rates of the two drying gas nozzles 221b can be set to be different. For example, the jet flow rate of the drying gas nozzle 221b at the oblique rear is less than that of the drying gas nozzle 221b directly behind. In the wafer edge region, only the drying gas nozzle 221b at the oblique rear is turned on, while the drying gas nozzle 221b directly behind is turned off. This not only changes the direction of the drying liquid ejection, but also reduces the purging intensity of the drying liquid, thereby reducing the backflow phenomenon of the drying liquid in the wafer edge region.

[0132] Figure 16 This is an enlarged schematic diagram showing the drying process reaching the edge region of wafer 201. From Figure 16 As can be seen, by introducing an additional drying gas nozzle 221b located at the rear, the flow direction of the drying liquid will be effectively changed, keeping the liquid ejection direction in the C direction, thereby suppressing the backflow phenomenon of the liquid and improving the uniformity and thoroughness of drying.

[0133] It should be noted that in this embodiment, only one drying gas nozzle 221b is added compared to Embodiment 1, but obviously the drying gas nozzle 221b is not limited to two. In other embodiments of the present invention, the drying gas nozzle 221b can also adopt a structural layout of three or more, and the direction of the dried liquid ejection can be changed by adjusting the on / off state and flow rate of multiple drying gas nozzles 221b. The jet direction of the drying gas nozzle 221b can also be designed to directly face the ideal liquid ejection direction to further increase the control effect of the liquid ejection direction.

[0134] Example 3

[0135] Please see Figures 17 to 18 This embodiment provides a wafer drying apparatus and method.

[0136] like Figure 17As shown, compared to the device provided in Embodiment 1, in this embodiment, the drying liquid nozzle includes a first drying liquid nozzle 321c and a second drying liquid nozzle 321d, wherein the flow rate of the drying liquid supplied by the first drying liquid nozzle 321c is greater than the flow rate of the drying liquid supplied by the second drying liquid nozzle 321d. Compared to the method provided in Embodiment 1, this embodiment uses the first drying liquid nozzle 321c to spray the drying liquid 302a in the central region of the wafer 301, and uses the second drying liquid nozzle 321d to spray the drying liquid 302a in the edge region of the wafer 301.

[0137] Similar to the device structure in Embodiment 1, in Figure 17 In the process, wafer 301 is adsorbed and fixed on wafer support stage 31 and rotated under the drive of rotary motor 311. A protective shell 312 is also provided around it to prevent liquid splashing caused by wafer rotation during operation. Drying gas 302b is supplied by drying gas nozzle 321b.

[0138] In Embodiment 1, the supply flow rate of the drying liquid varies considerably; the supply flow rate when spraying into the central region of the wafer is often much higher than that when spraying into the edge region. Using a single nozzle for supply, precise control of the supply flow rate is generally impossible. The drying method provided in this embodiment achieves precise control of the drying liquid flow rate by introducing nozzles with different drying liquid flow rates. Figure 10 As can be seen, in order to suppress the backflow effect of the liquid, the flow rate of the drying liquid needs to be gradually reduced in the edge region of the wafer 301, which places high demands on the precise control of the drying liquid flow rate. This embodiment ensures precise control of the drying liquid flow rate in the edge region of the wafer 301 by switching between the first drying liquid nozzle 321c and the second drying liquid nozzle 321d.

[0139] like Figure 17 As shown, when the drying process is located in the central region of the wafer 301, the drying liquid 302a is supplied by the first drying liquid nozzle 321c. At this time, the drying liquid flow rate is large, the drying rate is fast, and high operating efficiency is ensured. Figure 18 As shown, when the drying process is located in the edge region of the wafer 301, the second drying liquid nozzle 321d is switched to supply the drying liquid 302a. At this time, the drying liquid flow rate is relatively small, which facilitates precise control of gradually reducing the drying liquid flow rate to suppress the liquid backflow effect and improve drying uniformity.

[0140] Optionally, the first drying liquid nozzle 321c and the second drying liquid nozzle 321d are used simultaneously to spray the drying liquid 302a at the boundary between the central region and the edge region of the wafer 301. When switching between the first drying liquid nozzle 321c and the second drying liquid nozzle 321d, if the second drying liquid nozzle 321d is opened only after the first drying liquid nozzle 321c is closed, a brief boundary may exist, causing the supply of the drying liquid 302a to stop, which may result in insufficient drying. This embodiment effectively avoids the situation where the supply of the drying liquid 302a stops by using the first drying liquid nozzle 321c and the second drying liquid nozzle 321d to spray the drying liquid 302a at the boundary, thus reducing the defect of insufficient drying.

[0141] It should be noted that the scheme of using two different drying liquid nozzles in this embodiment can also be combined with the scheme of using multiple drying gas nozzles in Embodiment 2 to further enhance the control of the direction of the drying liquid flying away from the wafer, suppress the liquid backflow effect at the wafer edge, and improve the drying effect at the wafer edge.

[0142] In summary, the present invention provides a wafer drying apparatus and method. The wafer drying apparatus includes: a wafer support stage for fixing and rotating a wafer, the wafer including a central region and an edge region surrounding the central region; a drying medium supply module for supplying a drying medium to the surface of the wafer, the drying medium including at least a drying liquid; the drying medium supply module including a nozzle for spraying the drying medium and a motion unit for controlling the movement of the nozzle above the wafer; and a control module connected to the wafer support stage and the drying medium supply module for controlling the rotational speed of the wafer, the supply flow rate of the drying medium, and the moving speed of the nozzle, such that the direction in which the drying liquid leaves the wafer is oblique to the tangent of the wafer. This invention controls parameters such as wafer rotation speed, drying medium supply flow rate, and nozzle movement speed during wafer edge drying, causing the drying liquid to fly off the wafer from a direction oblique to the wafer tangent. This suppresses the backflow effect of liquid at the wafer edge, improves the drying effect at the wafer edge, reduces defects such as watermarks caused by insufficient drying, and increases product yield.

[0143] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A wafer drying apparatus characterized by comprising: The application relates to a wafer drying device, comprising: a wafer supporting table for fixing and rotating a wafer, the wafer comprising a central region and an edge region located at the periphery of the central region; a dry medium supply module for supplying a dry medium to the surface of the wafer, the dry medium comprising at least a dry liquid; the dry medium supply module comprising a nozzle for spraying the dry medium and a moving unit for controlling the movement of the nozzle above the wafer; a control module connected to the wafer supporting table and the dry medium supply module for controlling the rotation speed of the wafer, the supply flow of the dry medium and the moving speed of the nozzle, so that the direction of the dry liquid flying away from the wafer is oblique to the tangent of the wafer; the moving speed of the nozzle when the nozzle is located at the edge region of the wafer is smaller than the moving speed of the nozzle when the nozzle is located at the central region of the wafer.

2. The wafer drying apparatus according to claim 1, wherein the dry medium further comprises a dry gas; the dry medium supply module comprises a dry liquid nozzle for spraying the dry liquid and a dry gas nozzle for spraying the dry gas.

3. The wafer drying apparatus of claim 2, wherein the arrangement direction of the dry liquid nozzle and the dry gas nozzle is parallel to the moving direction of the dry liquid nozzle and the dry gas nozzle, and the dry gas nozzle is located behind the dry liquid nozzle when moving along the moving direction.

4. The wafer drying apparatus of claim 2, wherein the dry gas nozzle is a plurality of dry gas nozzles, and the arrangement direction of the plurality of dry gas nozzles is perpendicular to the moving direction of the dry liquid nozzle and the dry gas nozzle.

5. The wafer drying apparatus according to claim 2 or 4, wherein the dry liquid nozzle comprises a first dry liquid nozzle and a second dry liquid nozzle, and the supply flow of the dry liquid of the first dry liquid nozzle is greater than that of the second dry liquid nozzle.

6. The wafer drying apparatus of claim 2, wherein the dry medium supply module further comprises a dry gas source, a dry liquid source, a dry gas pipeline and a dry liquid pipeline; the dry gas pipeline is connected to the dry gas source and the dry gas nozzle, and the dry liquid pipeline is connected to the dry liquid source and the dry liquid nozzle.

7. The wafer drying apparatus of claim 6, wherein the control module comprises a dry gas flow control unit and a dry liquid flow control unit; the dry gas flow control unit is arranged on the dry gas pipeline and used for controlling the supply flow of the dry gas; and the dry liquid flow control unit is arranged on the dry liquid pipeline and used for controlling the supply flow of the dry liquid.

8. The wafer drying apparatus of claim 2, wherein the dry liquid comprises isopropyl alcohol, and the dry gas comprises nitrogen.

9. The wafer drying apparatus of claim 1, wherein the moving unit comprises a mechanical arm for mounting the nozzle and a swing motor for controlling the swing of the mechanical arm in a horizontal plane.

10. The wafer drying apparatus of claim 9, wherein the moving unit further comprises a lifting motor for lifting the mechanical arm in a vertical direction.

11. The wafer drying apparatus of claim 10, wherein the control module further comprises a mechanical arm control unit for controlling the movement of the mechanical arm, and the mechanical arm control unit is connected to the swing motor and the lifting motor.

12. The wafer drying apparatus of claim 1, wherein the control module comprises a rotation speed control unit for controlling the rotation speed of the wafer, and the wafer supporting table comprises a rotation motor for rotating the wafer supporting table, and the rotation speed control unit is connected to the rotation motor.

13. The wafer drying apparatus of claim 1, wherein At least one of the rotation speed of the wafer and the supply flow rate of the dry liquid is smaller when the nozzle is located at the edge region of the wafer than when the nozzle is located at the center region of the wafer.

14. A wafer drying method characterized by, The method comprises the following steps: A wafer support is provided, and a wafer is fixed on the wafer support, and the wafer support drives the wafer to rotate; the wafer comprises a center region and an edge region located at the periphery of the center region; A dry medium is sprayed on the surface of the wafer by a nozzle, and the dry medium at least comprises a dry liquid; during the spraying process, the nozzle moves from the center region of the wafer to the edge region of the wafer, and the rotation speed of the wafer, the supply flow rate of the dry liquid or the moving speed of the nozzle is controlled so that the direction in which the dry liquid flies away from the wafer is oblique to the tangent of the wafer; The moving speed of the nozzle is smaller when the nozzle is located at the edge region of the wafer than when the nozzle is located at the center region of the wafer.

15. The wafer drying method of claim 14, wherein At least one of the rotation speed of the wafer and the supply flow rate of the dry liquid is smaller when the nozzle is located at the edge region of the wafer than when the nozzle is located at the center region of the wafer.

16. The wafer drying method of claim 15, wherein When the nozzle is located at the edge region of the wafer, the rotation speed of the wafer, the supply flow rate of the dry liquid and the moving speed of the nozzle are gradually reduced during the movement of the nozzle to the edge of the wafer.

17. The wafer drying method of claim 14, wherein The dry medium further comprises a dry gas, the nozzle comprises a dry liquid nozzle for spraying the dry liquid and a dry gas nozzle for spraying the dry gas, and the dry gas nozzle is located behind the dry liquid nozzle when moving in the moving direction.

18. The wafer drying method of claim 17, wherein, The dry gas nozzle is a plurality of dry gas nozzles, and the arrangement direction of the plurality of dry gas nozzles is perpendicular to the moving direction of the dry liquid nozzle and the dry gas nozzle.

19. The wafer drying method according to claim 17 or 18, wherein The dry liquid nozzle comprises a first dry liquid nozzle and a second dry liquid nozzle, and the supply flow rate of the dry liquid of the first dry liquid nozzle is greater than that of the second dry liquid nozzle.

20. The wafer drying method of claim 19, wherein The first dry liquid nozzle and the second dry liquid nozzle are used to spray the dry liquid at the same time at the junction of the center region and the edge region of the wafer.

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