Wafer cleaning apparatus, wafer chuck thereof, and wafer cleaning method

Abstract

The application provides a wafer chuck in a semiconductor cleaning device, which comprises a chuck base, a mounting groove is formed in the central area of the top of the chuck base, a gas injection assembly for injecting gas is arranged in the mounting groove, a plurality of shaft holes are formed in the chuck base in a circumferential distribution, a plurality of wafer lifting shafts are correspondingly arranged in the shaft holes, the top end of each wafer lifting shaft is provided with an arc-shaped inclined table which is arranged around the axis of the wafer lifting shaft, the top surface of the arc-shaped inclined table comprises a transition curved surface and a first plane, the top surface of the wafer lifting shaft is a second plane, the first plane is higher than the second plane, and the transition curved surface is connected between the first plane and the second plane in a transition mode; and the application further comprises a driving assembly for driving the plurality of wafer lifting shafts to rotate so that the wafer is lifted up or lowered down by the bottom of the wafer edge contacting the first plane or the second plane. In the application, the wafer height is positioned by the plurality of wafer lifting shafts contacting the wafer edge, and the wafer cleaning efficiency is improved. The application further provides a wafer cleaning device and a wafer cleaning method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor process equipment, in particular to a wafer cleaning device and a wafer chuck thereof, and a wafer cleaning method. BACKGROUND

[0002] In the field of semiconductor process, the cleanliness of wafer surface has a vital influence on product yield, and how to effectively clean the wafer and improve the cleanliness of wafer surface has become an important research topic in the field.

[0003] In the existing single wafer cleaning device, there are usually two schemes for lifting the wafer. One is to lift the wafer carried on the chuck by a pin, that is, the pin passes through the chuck to lift the wafer carried thereon, so as to take or place the wafer, or the pin is retracted below the chuck to place the wafer. The other is to use air floating method, that is, to inject gas below the wafer to lift the wafer. However, both of the two schemes have defects difficult to overcome, and it is difficult to meet the higher requirements of wafer cleaning process on wafer lifting scheme.

[0004] Specifically, in the pin scheme, the pin is easy to cause wafer backside pollution or scratch when it contacts the wafer, and in some processes, such as backside cleaning device, the wafer front surface is downward, and physical contact between the chuck and the pattern part of the wafer is not allowed. Although the air floating method can avoid physical contact with the wafer, the stability and cleanliness of the air flow are required to be very high, and the lifting height of the wafer may be unstable, and the wafer surface may be contaminated by particles due to the cleanliness of the gas.

[0005] Therefore, how to provide a wafer lifting positioning scheme which can avoid contact with the wafer pattern part and ensure the stability of the wafer height has become a technical problem to be solved in the field. SUMMARY

[0006] The present application aims to provide a wafer cleaning device and a wafer chuck thereof, and a wafer cleaning method, which can improve the accuracy of wafer process position and wafer taking and placing position while avoiding contact with the wafer pattern part.

[0007] To achieve the above object, as one aspect of the present application, a wafer chuck in a semiconductor cleaning apparatus is provided, which comprises a chuck base having a top portion with a loading surface for loading a wafer, a central region of the top portion of the chuck base is formed with a mounting groove, a gas injection assembly for injecting gas between the loading surface and the wafer during a wafer cleaning process is arranged in the mounting groove, a plurality of shaft holes are formed in the chuck base and circumferentially distributed around the mounting groove, a plurality of wafer lifting shafts are correspondingly arranged in the plurality of shaft holes, a top end of each wafer lifting shaft is provided with an arc-shaped inclined platform circumferentially arranged around an axis of the wafer lifting shaft, a top surface of the arc-shaped inclined platform comprises a transition curved surface and a first plane, a top surface of the wafer lifting shaft is a second plane, the first plane is higher than the second plane, the second plane is higher than the loading surface, and the transition curved surface is connected between the first plane and the second plane; the wafer chuck further comprises a driving assembly for driving the plurality of wafer lifting shafts to rotate synchronously, so that the plurality of wafer lifting shafts are in contact with the bottom of the wafer edge through the first plane or through the second plane, to make the wafer loaded on the plurality of wafer lifting shafts ascend or descend.

[0008] Optionally, the top end of the wafer lifting shaft is further provided with a fixed column extending in a vertical direction, the arc-shaped inclined platform is arranged around the fixed column, and an axis of the fixed column is located on the other side of the wafer lifting shaft axis relative to the transition curved surface.

[0009] Optionally, when the driving assembly drives the plurality of wafer lifting shafts to rotate, the wafer descends from the first plane to the second plane through the transition curved surface or ascends from the second plane to the first plane through the transition curved surface, and when the wafer is loaded on the first plane or the second plane, the plurality of fixed columns are close to and clamp the wafer.

[0010] Optionally, the wafer lifting shaft has a gear segment located below the loading surface, the driving assembly comprises a driving source and a gear ring coaxially arranged with the chuck base, a side wall of the gear ring has a gear structure arranged around an axis thereof, the gear structure is engaged with the gear segment, and the driving source is used to drive the gear ring to rotate around the axis thereof, so as to drive the plurality of wafer lifting shafts to rotate synchronously.

[0011] Optionally, the wafer lifting shaft comprises a lifting shaft body and a gear piece, the top end of the lifting shaft body is provided with the arc-shaped inclined platform, and the gear piece is sleeved on the lifting shaft body and forms the gear segment.

[0012] Optionally, the bottom surface of the mounting groove comprises a first flat surface in the center and an inner tapered surface surrounding the first flat surface, a gas guide hole coaxial with the chuck base is formed on the first flat surface, the gas injection assembly comprises a gas injection cover, the gas injection cover is arranged in the mounting groove, and the bottom surface of the gas injection cover comprises a second flat surface and an outer tapered surface surrounding the second flat surface, a first gap is formed between the first flat surface and the second flat surface, and a second gap is formed between the outer tapered surface and the inner tapered surface.

[0013] An edge of the gas injection cover is formed with a plurality of injection holes penetrating from the top surface of the gas injection cover to the outer tapered surface and distributed equidistantly in the circumferential direction, and the gas is injected from the plurality of injection holes through the gas guide hole, the first gap and the second gap.

[0014] As a second aspect of the present application, a wafer cleaning device is provided, characterized in that the wafer cleaning device comprises the wafer chuck as described above.

[0015] Optionally, the wafer cleaning device further comprises a spraying assembly for spraying cleaning liquid to the wafer carried on the carrying surface.

[0016] As a third aspect of the present application, a wafer cleaning method is provided, characterized in that the wafer cleaning method is applied to the wafer cleaning device as described above, and the wafer cleaning method comprises:

[0017] transferring the wafer to be cleaned to the first plane;

[0018] controlling the driving assembly to drive the plurality of wafer lifting shafts to rotate synchronously in a first direction, so that the wafer on the first plane is lowered and transferred to the second plane;

[0019] controlling the gas injection assembly to inject gas and spray cleaning liquid to the wafer to perform wafer cleaning process;

[0020] controlling the gas injection assembly to stop injecting gas and spraying cleaning liquid to the wafer, and controlling the driving assembly to drive the plurality of wafer lifting shafts to rotate synchronously in a second direction, so that the wafer on the second plane is lifted and transferred to the first plane, to facilitate the wafer to be transferred out.

[0021] Optionally, the top end of the wafer lifting shaft further has a fixing column extending in the vertical direction, and the axis of the fixing column is located on the other side of the wafer lifting shaft axis relative to the transition curved surface; after the wafer is transferred to the first plane or the second plane, the plurality of fixing columns approach and clamp the wafer.

[0022] In the wafer cleaning device, the wafer chuck and the wafer cleaning method provided by the application, the multiple synchronously rotating wafer lifting shafts can realize accurate and stable positioning of the height of the wafer while only contacting the edge of the wafer, and the wafer can be smoothly switched between the state of contacting the first plane and the state of contacting the second plane. Therefore, the mechanical structure of the wafer chuck is simplified, the potential pollution factors caused by the structure such as the ejector pin are eliminated, the accuracy of the wafer process position and the wafer taking and placing position is improved, and the wafer taking and placing efficiency of the mechanical hand and the wafer cleaning efficiency are improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and serve to explain the principles of the application, but do not limit the application. In the drawings:

[0024] Figure 1 is a structural schematic diagram of the wafer chuck provided by the embodiment of the application;

[0025] Figure 2 is a sectional view of the wafer chuck provided by the embodiment of the application;

[0026] Figure 3 is a principle schematic diagram of the wafer lifting shaft in the wafer chuck rotating to the first direction provided by the embodiment of the application;

[0027] Figure 4 is a principle schematic diagram of the wafer lifting shaft in the wafer chuck rotating to the second direction provided by the embodiment of the application;

[0028] Figure 5 is a schematic diagram of the wafer located on the first plane of the multiple wafer lifting shafts in the wafer chuck provided by the embodiment of the application;

[0029] Figure 6 is a schematic diagram of the position relationship between the wafer and the first plane and the second plane when the wafer is located on the first plane of the multiple wafer lifting shafts in the wafer chuck provided by the embodiment of the application;

[0030] Figure 7 is a schematic diagram of the wafer located on the second plane of the multiple wafer lifting shafts in the wafer chuck provided by the embodiment of the application;

[0031] Figure 8 is a schematic diagram of the position relationship between the wafer and the first plane and the second plane when the wafer is located on the second plane of the multiple wafer lifting shafts in the wafer chuck provided by the embodiment of the application;

[0032] Figure 9 is a structural schematic diagram of the wafer cleaning device provided by the embodiment of the application;

[0033] Figure 10This is a schematic diagram showing the flow direction of the cleaning fluid and airflow during the wafer cleaning process in the wafer cleaning equipment provided in this embodiment of the invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Chuck base; 101. First flat surface; 102. Inner conical surface; 12. Base;

[0036] 2. Spray cap; 2a. Spray nozzle; 21. Spray assembly; 211. Second flat surface; 211a. Outer conical surface;

[0037] 3. Wafer lifting shaft; 32. Fixing column; 33. Gear section; 34. Lifting shaft body;

[0038] 341. Positioning step; 4. Wafer; 52. Gear ring; 53. Connecting flange; 6. Spray assembly;

[0039] 111, Arc-shaped inclined plane; 111a, First plane; 111c, Second plane; 111b, Transition surface. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0041] To address the aforementioned technical problems, as one aspect of the present invention, a wafer chuck for a semiconductor cleaning apparatus is provided, such as... Figures 1 to 4 As shown, the wafer chuck includes a chuck base 1. The top of the chuck base 1 has a bearing surface for supporting a wafer 4. A mounting groove is formed in the central region of the top of the chuck base 1. An air jet assembly 21 for spraying gas between the bearing surface and the wafer 4 during the wafer cleaning process is provided in the mounting groove. The chuck base 1 also has multiple shaft holes distributed circumferentially around the mounting groove. Multiple wafer lifting shafts 3 are correspondingly provided in the multiple shaft holes. An arc-shaped ramp 111 is provided at the top of the wafer lifting shaft 3 (on the second plane 111c) and circumferentially arranged around the axis of the wafer lifting shaft 3. The top of the arc-shaped ramp 111 is covered with... The wafer chuck includes a transition surface 111b and a first plane 111a. The top surface of the wafer lifting shaft 3 is a second plane 111c. The first plane 111a is higher than the second plane 111c, and the second plane 111c is higher than the bearing surface. The transition surface 111b is a transitional connection between the first plane 111a and the second plane 111c. The wafer chuck also includes a drive assembly for driving multiple wafer lifting shafts 3 to rotate synchronously, so that the multiple wafer lifting shafts 3 contact the bottom edge of the wafer 4 through the first plane 111a or through the second plane 111c, so that the wafer 4 carried by the multiple wafer lifting shafts 3 rises or falls.

[0042] It should be noted that in the present application, the transition connection refers to that the height of the transition curved surface 111b changes smoothly along the circumferential direction of the wafer lifting shaft 3 axis, and the height of the transition curved surface 111b is flush with the height of the first plane 111a and the second plane 111c respectively.

[0043] The wafer chuck provided by the present application comprises a plurality of circumferentially distributed wafer lifting shafts 3, and each wafer lifting shaft 3 comprises a first plane 111a and a second plane 111c connected by a transition curved surface 111b, so that when the plurality of wafer lifting shafts 3 rotate synchronously, the plurality of wafer lifting shafts 3 can be switched between the state of contacting the wafer 4 through the first plane 111a or the second plane 111c at the same time.

[0044] Specifically, when the first plane 111a of the plurality of wafer lifting shafts 3 is directed towards the wafer 4 (i.e. towards the central region), as shown in Figure 5 、 Figure 6 , the wafer 4 has sufficient gap with the bearing surface, so that the wafer 4 can be conveniently placed on the first plane 111a of the plurality of wafer lifting shafts 3 by the mechanical hand, or the wafer 4 placed on the first plane 111a of the plurality of wafer lifting shafts 3 can be taken away by the mechanical hand; after the wafer 4 to be cleaned is placed on the first plane 111a, as the plurality of wafer lifting shafts 3 rotate synchronously, the transition curved surface 111b and the second plane 111c of each wafer lifting shaft 3 rotate towards the wafer 4 in turn, the wafer 4 is first transferred from the first plane 111a to the transition curved surface 111b, and gradually lowered to the corresponding height of the second plane 111c under the guidance of the rotating transition curved surface 111b, and finally, as shown in Figure 7 、 Figure 8 , the wafer 4 falls on the second plane 111c when the second plane 111c rotates towards the wafer 4, so as to perform the wafer cleaning process.

[0045] It should be noted that the purpose of the gas injection assembly 21 for injecting gas between the bearing surface and the wafer 4 in the wafer cleaning process is to avoid the cleaning liquid from splashing into the gap between the bearing surface and the wafer 4 and corroding the back surface of the wafer 4, and the principle is as shown in Figure 10 . Moreover, the gas injection function of the gas injection assembly 21 can improve the stability of the wafer 4 placed on the second plane 111c, and specifically:

[0046] In the wafer cleaning process, the gas injected by the gas injection assembly 21 flows along the direction of the arrow in the chuck as shown in Figure 10The arrows shown flow in a direction to form a gas protection layer, ensuring that the cleaning liquid does not flow to the lower surface of the wafer 4 during the cleaning process, thereby forming a gas protection layer on the lower surface of the wafer 4. At the same time, due to the high gas flow rate on the back surface of the wafer 4 and the slow gas flow rate on the front surface of the wafer 4, according to the Bernoulli principle, the gas pressure on the back surface of the wafer 4 is less than the gas pressure on the front surface of the wafer 4, so that the wafer 4 is subjected to a vertical downward pressure, and the wafer 4 is firmly pressed on the second plane 111c together with the weight of the wafer 4.

[0047] In the present application, the plurality of synchronously rotating wafer lifting shafts 3 can precisely and stably position the height of the wafer 4 while only contacting the edge of the wafer 4 (the contact area of the first plane 111a, the second plane 111c and the transition curved surface 111b with the edge of the wafer 4 is small, and the contact position is the invalid area of the edge of the wafer 4, which has no effect on the surface pattern of the wafer 4), so that the wafer 4 can be smoothly switched between the state of contacting the first plane 111a and the state of contacting the second plane 111c. Thus, while simplifying the mechanical structure of the wafer chuck and eliminating the potential contamination factors caused by the structure of the thimble, the accuracy of the wafer process position and the wafer pick-and-place position is improved, and the wafer pick-and-place efficiency of the robot and the wafer cleaning efficiency are improved.

[0048] To further improve the stability and accuracy of the wafer position, as a preferred embodiment of the present application, as shown in Figure 2 、 Figure 3 、 Figure 4 The top end of the wafer lifting shaft 3 is also provided with a fixed column 32 extending in the vertical direction, and the arc-shaped inclined table 111 surrounds the fixed column 32, and the axis of the fixed column 32 is located on the other side of the axis of the wafer lifting shaft 3 relative to the transition curved surface 111b (i.e. on the side corresponding to the step between the first plane 111a and the second plane 111c).

[0049] In the embodiment of the present application, the top end of the wafer lifting shaft 3 also has a fixing column 32, and the fixing column 32 is designed eccentrically, so as to clamp and release the wafer 4. Specifically, when the driving assembly drives the plurality of wafer lifting shafts 3 to rotate, the wafer 4 can be lowered from the first plane 111a to the second plane 111c through the transition curve 111b, or be raised from the second plane 111c to the first plane 111a through the transition curve 111b. Regardless of whether the wafer 4 is carried on the first plane 111a or the second plane 111c, the plurality of fixing columns 32 can approach and clamp the wafer 4. When the plurality of wafer lifting shafts 3 are all rotated to the transition curve 111b facing the center of the wafer chuck, the plurality of fixing columns 32 are farthest from each other, the plurality of fixing columns 32 enclose the largest defined space, and the plurality of fixing columns 32 do not contact the edge of the wafer 4. When the plurality of wafer lifting shafts 3 are all rotated to the fixing column 32 completely facing the center of the wafer chuck relative to the axis of the wafer lifting shaft 3, the plurality of fixing columns 32 are closest to each other, and the plurality of fixing columns 32 enclose a space insufficient to accommodate the wafer 4. Therefore, when the wafer lifting shaft 3 is rotated from the state of the transition curve 111b facing the wafer 4 to the first plane 111a or the second plane 111c, and then continues to rotate in the same direction, the plurality of fixing columns 32 will gradually approach the edge of the wafer 4 until clamping the side of the wafer 4, and the wafer lifting shaft 3 cannot continue to rotate in the same direction.

[0050] The clamping of the wafer 4 can play a role in two stages. Firstly, when the gas jetting assembly 21 starts to jet gas, the wafer lifting shaft 3 in contact with the wafer 4 on the first plane 111a is driven to rotate to the corresponding limit state on the first plane 111a side, so that the plurality of fixing columns 32 clamp the side of the wafer 4, fix the wafer 4 at the corresponding height of the first plane 111a, and avoid the movement of the wafer 4 under the action of the unstable flow field generated when the gas jetting assembly 21 starts to jet gas, thereby improving the stability of the position of the wafer 4. Secondly, when the wafer 4 is lowered to be in contact with the second plane 111c, after the pressure difference (between the upper and lower surfaces of the wafer 4) generated by the gas jetted by the gas jetting assembly 21 presses the wafer 4 on the second plane 111c of the plurality of wafer lifting shafts 3, the wafer lifting shaft 3 can be driven to rotate to the corresponding limit state on the second plane 111c side, so that the plurality of fixing columns 32 clamp the side of the wafer 4, fix the wafer 4 at the corresponding height of the second plane 111c, and further improve the stability of the position of the wafer 4.

[0051] The embodiment of the present application does not specifically limit the rotating direction of the wafer lifting shaft 3. For example, as shown in FIG. 1, as an optional embodiment of the present application, the wafer lifting shaft 3 can rotate clockwise (from the top view) to make the second plane 111c, the transition curve 111b and the first plane 111a in turn face the wafer 4, that is, to raise the wafer 4 (as shown in FIG. 1). Figures 3 to 8 The embodiment of the present application does not specifically limit the rotating direction of the wafer lifting shaft 3. For example, as shown in FIG. 1, as an optional embodiment of the present application, the wafer lifting shaft 3 can rotate clockwise (from the top view) to make the second plane 111c, the transition curve 111b and the first plane 111a in turn face the wafer 4, that is, to raise the wafer 4 (as shown in FIG. 1). Figures 4 to 6as shown). By anticlockwise rotation, the first plane 111a, the transition curved surface 111b and the second plane 111c are sequentially oriented to the wafer 4, i.e. the wafer 4 is lowered (as shown). Alternatively, in other embodiments of the present application (not shown), the wafer lifting shaft 3 can also rotate clockwise (from the top view) to sequentially orient the first plane 111a, the transition curved surface 111b and the second plane 111c to the wafer 4, i.e. to lower the wafer 4; and anticlockwise to sequentially orient the second plane 111c, the transition curved surface 111b and the first plane 111a to the wafer 4, i.e. to raise the wafer 4. Figure 3 、 Figure 7 、 Figure 8 Alternatively, in other embodiments of the present application (not shown), the wafer lifting shaft 3 can also rotate clockwise (from the top view) to sequentially orient the first plane 111a, the transition curved surface 111b and the second plane 111c to the wafer 4, i.e. to lower the wafer 4; and anticlockwise to sequentially orient the second plane 111c, the transition curved surface 111b and the first plane 111a to the wafer 4, i.e. to raise the wafer 4.

[0052] The present application does not limit how to control the synchronous rotation of the plurality of wafer lifting shafts 3, for example, a plurality of motors can be used to drive the plurality of wafer lifting shafts 3 to rotate synchronously according to the same control signal, or the same belt can be used to connect the plurality of wafer lifting shafts 3 to ensure the synchronous rotation of the plurality of wafer lifting shafts 3.

[0053] To simplify the mechanical structure of the wafer chuck and improve the stability of the synchronous rotation of the plurality of wafer lifting shafts 3, as a preferred embodiment of the present application, as shown in Figures 2 to 4 the wafer lifting shaft 3 has a gear segment 33 below the bearing surface, the driving assembly includes a driving source and a gear ring 52 coaxially arranged with the chuck base 1, the sidewall of the gear ring 52 has a gear structure arranged around the axis thereof, and the gear structure is engaged with the gear segment 33, and the driving source is used to drive the gear ring 52 to rotate around the axis thereof to drive the plurality of wafer lifting shafts 3 to rotate synchronously.

[0054] In the embodiments of the present application, the driving assembly includes a driving source and a gear ring 52, and the gear structure on the gear ring 52 is combined with the gear segment 33 of the wafer lifting shaft 3 to drive, so as to ensure the synchronism of the rotation of the plurality of wafer lifting shafts 3 through a simple mechanical structure. It should be noted that in the embodiments in which the plurality of wafer lifting shafts 3 are driven to rotate synchronously by the gear ring 52, the rotation direction of the plurality of wafer lifting shafts 3 needs to be consistent.

[0055] The present application does not limit how to make the gear segment 33 on the wafer lifting shaft 3, for example, the gear segment 33 can be directly made by turning on the wafer lifting shaft 3.

[0056] To reduce the maintenance cost of replacing the easily-worn structure, as a preferred embodiment of the present application, the wafer lifting shaft 3 can be assembled by a shaft body and a detachable gear structure, specifically, as shown in Figure 3 、 Figure 4As shown in the figure, the wafer lifting shaft 3 comprises a lifting shaft body 34 and a gear part, the top end of the lifting shaft body 34 is provided with an arc-shaped inclined table 111, and the gear part is sleeved on the lifting shaft body 34 and forms a gear section 33.

[0057] In the embodiment of the present application, the wafer lifting shaft 3 is assembled by the lifting shaft body 34 and the gear part sleeved on the lifting shaft body 34, so that when the gear part is excessively worn, the lifting shaft body 34 can be reserved and only the gear part is replaced, thereby reducing the maintenance cost of replacing parts. In order to further reduce the maintenance cost, preferably, the gear part can be a standard part purchased in bulk on the market.

[0058] In order to facilitate positioning of the vertical position of the gear part, preferably, as shown in Figure 3 , Figure 4 the lifting shaft body 34 is formed with a positioning step 341.

[0059] The embodiment of the present application does not make specific limitation on the position of the gear structure on the gear ring 52, for example, as an optional embodiment of the present application, as shown in Figure 2 the gear structure is formed on the outer side of the gear ring 52, that is, the gear sections 33 of the plurality of wafer lifting shafts 3 are arranged on the outer side of the gear ring 52 and are engaged with the outer teeth of the gear ring 52. Alternatively, in other embodiments of the present application, the gear structure on the gear ring 52 can be formed on the inner side wall of the gear ring 52 (i.e. formed as an internal gear), the gear ring 52 is sleeved on the outer side of the gear section 33 of the plurality of wafer lifting shafts 3 and is engaged with the plurality of wafer lifting shafts 3 through the internal teeth.

[0060] The embodiment of the present application does not make specific limitation on how the driving source is connected with the gear ring 52, for example, as an optional embodiment of the present application, as shown in Figure 2 the driving source can be a rotary motor with an output shaft coaxial with the wafer chuck, and the output shaft of the driving source is fixedly connected with the gear ring 52 through a connecting flange 53.

[0061] The embodiment of the present application does not make specific limitation on how to fix the axis of the wafer lifting shaft 3, for example, optionally, as shown in Figure 2 the wafer chuck further comprises a base 12 arranged below the chuck base 1, the base 12 is sealingly connected with the chuck base 1 to form a transmission cavity, the gear ring 52, the connecting flange 53 and the gear section 33 of the wafer lifting shaft 3 are all located in the transmission cavity, a plurality of mounting blind holes are formed on the bottom surface of the base 12, and the bottom end of the wafer lifting shaft 3 is arranged in the corresponding mounting blind hole of the base 12. In order to reduce the friction of the wafer lifting shaft 3 rotating in the mounting blind hole, preferably, the bottom end of the wafer lifting shaft 3 is installed in the mounting blind hole through a bearing.

[0062] The embodiment of the present application does not make specific limitation on the structure of the air jet assembly 21, for example, optionally, as shown inFigure 1 、 Figure 2 As shown in FIG. 1, the bottom surface of the mounting groove comprises a first flat surface 101 in the center and an inner tapered surface 102 surrounding the first flat surface 101, the first flat surface 101 is formed with a gas guide hole (not shown) coaxial with the chuck base 1, the jetting assembly 21 comprises a jet cover 2, the jet cover 2 is arranged in the mounting groove, and the bottom surface of the jet cover 2 comprises a second flat surface 211 and an outer tapered surface 211a surrounding the second flat surface 211, a first gap is formed between the first flat surface 101 and the second flat surface 211, and a second gap is formed between the outer tapered surface 211a and the inner tapered surface 102;

[0063] The edge of the jet cover 2 is formed with a plurality of jet holes 2a penetrating from the top surface of the jet cover 2 to the outer tapered surface 211a and distributed equidistantly in the circumferential direction, when the gas is jetted, the gas is jetted out from the plurality of jet holes 2a through the gas guide hole, the first gap and the second gap, and blows to the back surface of the wafer 4 to form a gas protection layer.

[0064] In order to improve the stability of the gas flow on the back surface of the wafer 4, preferably, the jetting direction of the plurality of jet holes 2a is at an angle (for example, can be between 45° and 20°) with the bearing surface, as shown in FIG. 2, after the gas flow is jetted out, it blows outwardly to the back surface of the wafer 4 to form a gas protection layer. Figure 10

[0065] The embodiment of the present application does not make specific limitation on the composition of the gas jetted by the jetting assembly 21, for example, as an easy-to-implement embodiment of the present application, the jetting assembly 21 is used to jet nitrogen to the back surface of the wafer 4. The embodiment of the present application does not make specific limitation on the gas flow and pressure of the gas jetted by the jetting assembly 21, and the gas flow and pressure flowing into the tapered gas cavity can be adjusted according to the requirements of the wafer cleaning process, so that the back suction force borne by the wafer reaches the required size.

[0066] The embodiment of the present application does not make specific limitation on the number of wafer lifting shafts 3, for example, as an optional embodiment of the present application, as shown in FIG. 3, the wafer chuck can comprise six wafer lifting shafts 3, and the six wafer lifting shafts 3 are equidistantly distributed around the axis of the chuck base 1. Figure 1 、 Figure 2

[0067] As a second aspect of the present application, a wafer cleaning device is provided, which comprises the wafer chuck provided by the embodiment of the present application.

[0068] ​​In the wafer cleaning device provided by the present application, the plurality of synchronous rotating wafer lifting shafts 3 of the wafer chuck can realize accurate and stable positioning of the height of the wafer 4 while only contacting the edge of the wafer 4, and make the wafer 4 smoothly switch between the state of contacting the first plane 111a and the state of contacting the second plane 111c. Therefore, the mechanical structure of the wafer chuck is simplified, the potential pollution factors caused by the structure such as the ejector pin are eliminated, the accuracy of the wafer process position and the wafer taking and placing position is improved, and the wafer taking and placing efficiency of the mechanical hand and the wafer cleaning efficiency are improved.

[0069] The embodiments of the present application do not make specific limitations on other structures of the wafer cleaning device, for example, optionally, as shown in Figure 9 The wafer cleaning device further comprises a spraying assembly 6, which is used for spraying cleaning liquid to the wafer 4 carried on the bearing surface.

[0070] As a third aspect of the present application, a wafer cleaning method is provided, which is applied to the wafer cleaning device provided by the present application, and the wafer cleaning method comprises the following steps:

[0071] Step S1, transmitting the received wafer 4 to be cleaned to the first plane 111a;

[0072] Step S2, controlling the driving assembly to drive the plurality of wafer lifting shafts 3 to synchronously rotate in the first direction, so that the wafer 4 located on the first plane 111a is lowered and transferred to the second plane 111c;

[0073] Step S3, controlling the gas jetting assembly 21 to jet gas, and (controlling the spraying assembly 6) to spray cleaning liquid to the wafer 4, so as to perform wafer cleaning process;

[0074] Step S4, controlling the gas jetting assembly 21 to stop jetting gas, (controlling the spraying assembly 6) to stop spraying cleaning liquid to the wafer 4, and controlling the driving assembly to drive the plurality of wafer lifting shafts 3 to synchronously rotate in the second direction, so that the wafer 4 located on the second plane 111c is lifted and transferred to the first plane 111a, so as to transmit the cleaned wafer 4.

[0075] It should be noted that steps S1 to S4 are a cleaning process cycle corresponding to a single wafer 4, and steps S1 to S4 are cyclically executed multiple times in the process of sequentially cleaning multiple wafers 4. The first plane 111a of the plurality of wafer lifting shafts 3 is oriented towards the axis of the wafer chuck in step S1, which is the initial state of the wafer lifting shafts 3. In some embodiments of the present application, the action of stopping the gas injection assembly 21 from injecting gas in step S4 can also be changed to be performed in step S1. That is, step S4 only includes controlling the gas injection assembly 21 to stop injecting gas, and in step S1, before receiving the wafer 4 to be cleaned, the plurality of wafer lifting shafts 3 are first driven to rotate to the first plane 111a oriented towards the axis of the wafer chuck, so that the wafer 4 located on the second plane 111c is lifted and transferred to the first plane 111a, in order to facilitate the transmission of the cleaned wafer 4 (i.e., the plurality of wafer lifting shafts 3 are restored to the initial state).

[0076] In the wafer cleaning method provided by the present application, the plurality of synchronously rotating wafer lifting shafts 3 of the wafer chuck only realize accurate and stable positioning of the height of the wafer 4 by contacting the edge of the wafer 4, so that the wafer 4 is smoothly switched between the state of contacting the first plane 111a and the state of contacting the second plane 111c. Thus, while simplifying the mechanical structure of the wafer chuck and eliminating potential contamination factors caused by structures such as the ejector pin, the accuracy of the wafer process position and the wafer pick-and-place position is improved, and the pick-and-place efficiency of the wafer by the robot and the wafer cleaning efficiency are further improved.

[0077] To further improve the stability and accuracy of the wafer position, as a preferred embodiment of the present application, as shown in Figure 2 、 Figure 3 、 Figure 4 The top end of the wafer lifting shaft 3 also has a fixed column 32 extending in the vertical direction, and the axis of the fixed column 32 is located on the other side of the axis of the wafer lifting shaft 3 relative to the transition surface 111b. After the wafer 4 is transferred to the first plane 111a or the second plane 111c, the plurality of fixed columns 32 approach and clamp the wafer 4.

[0078] In the embodiment of the present application, the top end of the wafer lifting shaft 3 is also provided with a fixing column 32, and the fixing column 32 is designed eccentrically, so as to clamp and release the wafer 4. Before the gas jetting assembly 21 starts to jet gas, the driving assembly drives the wafer lifting shaft 3, which is in contact with the wafer 4 and the first plane 111a, to rotate to the limit state corresponding to the first plane 111a, so that the fixing columns 32 clamp the side edges of the wafer 4, fix the wafer 4 at the height corresponding to the first plane 111a, and avoid the wafer 4 from moving under the action of the unstable flow field generated when the gas jetting assembly 21 starts to jet gas, so as to improve the stability of the position of the wafer 4. After the wafer 4 is lowered to be in contact with the second plane 111c, before the wafer cleaning process is performed, the driving assembly stably presses the wafer 4 on the second plane 111c of the plurality of wafer lifting shafts 3 under the pressure difference generated by the gas jetting of the gas jetting assembly 21, then drives the wafer lifting shaft 3 to rotate to the limit state corresponding to the second plane 111c, so that the fixing columns 32 clamp the side edges of the wafer 4, fix the wafer 4 at the height corresponding to the second plane 111c, and further improve the stability of the position of the wafer 4.

[0079] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A wafer chuck in a semiconductor cleaning apparatus, characterized in that, The device includes a chuck base with a bearing surface on its top for supporting a wafer. A mounting groove is formed in the central region of the top of the chuck base. An air jetting assembly is disposed in the mounting groove for injecting gas between the bearing surface and the wafer during a wafer cleaning process. The chuck base also has multiple axial holes circumferentially distributed around the mounting groove. Multiple wafer lifting shafts are correspondingly disposed in the multiple axial holes. The top of each wafer lifting shaft has an arc-shaped ramp circumferentially arranged around its axis. The top surface of the arc-shaped ramp includes a transition surface and a first plane, while the top surface of the wafer lifting shaft is a second plane. Furthermore, the first plane is higher than the second plane, the second plane is higher than the bearing surface, and the transition surface connects the first plane and the second plane. The height of the transition surface changes smoothly along the axis surrounding the wafer lifting shaft, and the two ends of the transition surface are flush with the heights of the first plane and the second plane, respectively. The wafer chuck also includes a drive assembly for driving multiple wafer lifting shafts to rotate synchronously, so that the multiple wafer lifting shafts contact the bottom of the wafer edge through the first plane or through the second plane, so that the wafers carried by the multiple wafer lifting shafts rise or fall.

2. The wafer chuck according to claim 1, characterized in that, The top of the wafer lifting shaft is also provided with a fixed post extending in a vertical direction. The arc-shaped ramp surrounds the fixed post, and the axis of the fixed post is located on the other side of the axis of the wafer lifting shaft relative to the transition surface.

3. The wafer chuck according to claim 2, characterized in that, When the drive assembly drives the plurality of wafer lifting shafts to rotate, the wafer descends from the first plane to the second plane via the transition surface or rises from the second plane to the first plane via the transition surface. When the wafer is supported on the first plane or the second plane, the plurality of fixing posts approach and clamp the wafer.

4. The wafer chuck according to any one of claims 1 to 3, characterized in that, The wafer lifting shaft has a gear segment located below the bearing surface. The drive assembly includes a drive source and a gear ring coaxially arranged with the chuck base. The sidewall of the gear ring has a gear structure arranged around its axis, and the gear structure meshes with the gear segment. The drive source is used to drive the gear ring to rotate around its axis, so as to drive multiple wafer lifting shafts to rotate synchronously.

5. The wafer chuck according to claim 4, characterized in that, The wafer lifting shaft includes a lifting shaft body and a gear component. The top end of the lifting shaft body is provided with the arc-shaped inclined platform, and the gear component is sleeved on the lifting shaft body to form the gear segment.

6. The wafer chuck according to any one of claims 1 to 3, characterized in that, The bottom surface of the mounting groove includes a first flat surface located in the center and an inner conical surface surrounding the first flat surface. An air guide hole coaxial with the chuck base is formed on the first flat surface. The jet assembly includes a spray cover, which is disposed in the mounting groove. The bottom surface of the spray cover includes a second flat surface and an outer conical surface surrounding the second flat surface. A first gap is formed between the first flat surface and the second flat surface, and a second gap is formed between the outer conical surface and the inner conical surface. The edge of the spray cap has a plurality of spray holes that extend from the top surface of the spray cap to the outer conical surface and are circumferentially spaced. The gas is ejected from the plurality of spray holes through the air guide hole, the first gap and the second gap.

7. A wafer cleaning device, characterized in that, The wafer cleaning equipment includes a wafer chuck as described in any one of claims 1 to 6.

8. The wafer cleaning equipment according to claim 7, characterized in that, The wafer cleaning equipment further includes a spray assembly for spraying cleaning fluid onto the wafer from the bearing surface.

9. A wafer cleaning method, characterized in that, The wafer cleaning method is applied to the wafer cleaning equipment according to claim 7 or 8, characterized in that the wafer cleaning method includes: The wafer to be cleaned is transferred to the first plane; The drive assembly is controlled to drive multiple wafer lifting axes to rotate synchronously in a first direction, so that the wafers located on the first plane are lowered and transferred to the second plane; The jet assembly is controlled to spray gas and spray cleaning fluid onto the wafer to perform a wafer cleaning process. The jet assembly is controlled to stop spraying gas and stop spraying cleaning fluid onto the wafer. The drive assembly is also controlled to drive multiple wafer lifting axes to rotate synchronously in the second direction, so that the wafer located on the second plane rises and is transferred to the first plane for easy transport.

10. The wafer cleaning method according to claim 9, characterized in that, The top of the wafer lifting shaft also has a fixing post extending in a vertical direction, and the axis of the fixing post is located on the other side of the wafer lifting shaft axis relative to the transition surface; after the wafer is transferred to the first plane or the second plane, the plurality of fixing posts approach and clamp the wafer.

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