A wafer cleaning and drying device

Abstract

This invention provides a wafer cleaning and drying apparatus, comprising: a tank body, a tank cover, a first drain pipe, a second drain pipe, and a buffer tank. The tank body includes an inner tank and an outer tank, with the outer tank located outside the inner tank. The opening of the outer tank is higher than the opening of the inner tank, and the openings of the outer and inner tanks are connected. The inner tank is filled with cleaning fluid for cleaning the wafers. The tank cover is located at the top of the tank body, forming a drying space between the cover and the top of the inner tank. The first drain pipe is connected to the bottom of the outer tank, and the second drain pipe is connected to the bottom of the inner tank. Both the first and second drain pipes are connected to the buffer tank. During the process of draining the cleaning fluid from the outer and inner tanks to the factory end, it is first drained into the buffer tank through the first and second drain pipes for temporary storage. This reduces the negative pressure in the first and second drain pipes, thereby reducing the negative pressure inside the tank and maintaining a stable drying gas atmosphere within the tank, thus improving the wafer drying effect.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing technology, and in particular to a wafer cleaning and drying device. Background Technology

[0002] In semiconductor manufacturing, wet cleaning is the most widely used wafer cleaning technology. Wafer drying is the final step in the wet cleaning process, which requires ensuring the effective removal of residual moisture from the wafer surface and controlling the surface cleanliness.

[0003] Currently, the wafer cleaning and drying equipment has a cleaning space and a drying space inside the tank, with drying gas flowing into the drying space. During the wafer cleaning and drying process, the cleaning solution in the cleaning space is discharged to the factory end through a drain pipe.

[0004] However, because there is a high negative pressure in the process of the drain pipe draining the cleaning fluid from the cleaning space to the factory end, the drying gas in the drying space will be drawn away due to the high negative pressure in the drain pipe, which will cause the wafer to not be dried normally. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a wafer cleaning and drying device, including: a tank, a tank cover, a first drain pipe, a second drain pipe, and a buffer tank; The tank includes an inner tank and an outer tank. The outer tank is located outside the inner tank. The opening of the outer tank is higher than the opening of the inner tank, and the opening of the outer tank is connected to the opening of the inner tank. The inner tank is filled with cleaning fluid to clean the wafer. The tank cover is located at the top of the tank body, and a drying space is formed between the tank cover and the top of the inner tank. The drying space is filled with drying gas to dry the cleaned wafer. The first drain pipe is connected to the bottom of the outer tank, and the second drain pipe is connected to the bottom of the inner tank. Both the first drain pipe and the second drain pipe are connected to the buffer tank.

[0006] Optionally, a first drain port is provided at the bottom of the outer tank, a first inlet port is provided on the buffer tank, and the two ends of the first drain pipe are respectively connected to the first drain port and the first inlet port.

[0007] Optionally, the bottom of the inner tank is provided with a second drain port, the buffer tank is provided with a second inlet port, and the two ends of the second drain pipe are respectively connected to the second drain port and the second inlet port.

[0008] Optionally, a three-way valve is provided on the second drain port. The three-way valve includes a first valve port, a second valve port, and a third valve port. The first valve port is connected to the inner tank, the second valve port is connected to the second drain pipe, and the third valve port is connected to the exhaust pipe.

[0009] Optionally, the buffer tank is further provided with a first liquid outlet, which is connected to the plant terminal via a third drain pipe.

[0010] Optionally, the buffer tank is also provided with a second liquid outlet, which is connected to the plant terminal through a fourth drain pipe.

[0011] Optionally, a valve is provided on the fourth drain pipe.

[0012] Optionally, the bottom of the inner tank is provided with an exhaust port, which is connected to an exhaust pipe for discharging dry gas from the inner tank.

[0013] Optionally, the bottom of the inner tank is provided with a liquid injection port for connecting a cleaning fluid injection pipe, and the cleaning fluid is injected into the tank in sequence through the cleaning fluid injection pipe and the liquid injection port.

[0014] Optionally, the inner side of the trough cover is provided with a plurality of nozzles facing the drying space, and the nozzles are connected to a gas source for introducing drying gas into the drying space.

[0015] Compared with the prior art, the technical solution of this utility model embodiment has the following beneficial effects: This invention connects the first drain pipe of the outer tank and the second drain pipe of the inner tank to a buffer tank. During the process of draining the cleaning fluid from the outer and inner tanks to the factory end, it is first drained into the buffer tank through the first and second drain pipes for temporary storage. Therefore, the negative pressure in the first and second drain pipes is reduced, thereby reducing the negative pressure in the tank and keeping the dry gas atmosphere in the tank stable, thus improving the drying effect of the wafer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a wafer cleaning and drying apparatus provided in an embodiment of the present invention; Figure 2This is a partial structural schematic diagram of a wafer cleaning and drying apparatus provided in one embodiment of the present invention; Explanation of reference numerals in the attached figures: 1--Tank body; 101--Outer groove; 102--Inner groove; 2--Wafer; 3--Slot cover; 4-- Nozzle; 5--Dry space; 6--First drain pipe; 7--Second drain pipe; 8--Buffer tank; 9--Third drain pipe; 10--Fourth drain pipe; 11--Second valve; 12--Drain valve; 13--Three-way valve; 1301 -- First valve port; 1302 -- Second valve port; 1303 Third valve port. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The terms "above" and "over," and any variations thereof, are intended to describe positional relationships and do not imply direct contact between the described objects.

[0020] Please refer to Figure 1 and Figure 2 This utility model provides a wafer cleaning and drying device, which may include a tank body 1, a tank cover 3, a first drain pipe 6, a second drain pipe 7, and a buffer tank 8.

[0021] The tank 1 may include an inner tank 102 and an outer tank 101. The outer tank 101 is disposed outside the inner tank 102. The opening of the outer tank 101 is higher than the opening of the inner tank 102, and the opening of the outer tank 101 is connected to the opening of the inner tank 102. The inner tank 102 is filled with cleaning fluid to clean the wafer 2.

[0022] In one embodiment, the outer groove 101 is arranged around the inner groove 102.

[0023] In one embodiment, the bottom of the outer tank 101 is higher than the bottom of the inner tank 102. Since the cleaning fluid overflows into the outer tank 101 after the inner tank 102 is filled, and the outer tank 101 promptly removes the overflowing fluid, it is unnecessary for the bottom of the outer tank 101 to be too low. If the bottom of the outer tank 101 is too low, it may trap dirt and grime, and make cleaning difficult. Therefore, in this embodiment, the bottom of the outer tank 101 is higher than the bottom of the inner tank 102, which helps maintain the cleanliness of the outer tank 101 to a certain extent, and makes cleaning easier even if there is dirt inside.

[0024] In this embodiment, the tank cover 1 is located at the top of the tank body 1, and a drying space 5 is formed between the tank cover 1 and the top of the inner tank 102. The drying space 5 is filled with drying gas to dry the cleaned wafer 2.

[0025] In this embodiment, the first drain pipe 6 is connected to the bottom of the outer tank 101, the second drain pipe 7 is connected to the bottom of the inner tank 102, and both the first drain pipe 6 and the second drain pipe 7 are connected to the buffer tank 8.

[0026] This invention connects the first drain pipe 6 of the outer tank 101 and the second drain pipe 7 of the inner tank 102 to the buffer tank 8. During the process of draining the cleaning fluid from the outer tank 101 and the inner tank 102 to the factory end, it is first drained into the buffer tank 8 through the first drain pipe 6 and the second drain pipe 7 for temporary storage. Therefore, the negative pressure in the first drain pipe 6 and the second drain pipe 7 is reduced, thereby reducing the negative pressure in the tank 1, so that the dry gas atmosphere in the tank 1 remains stable, which can improve the drying effect of the wafer.

[0027] In this embodiment, the first drain pipe 6 and the second drain pipe 7 can be connected to the same inlet on the buffer tank 8 at the same time, or they can be connected to different inlets. This utility model does not impose any specific restrictions on this.

[0028] As one embodiment, the bottom of the outer tank 101 is provided with a first drain port, the buffer tank 8 is provided with a first inlet port, and the two ends of the first drain pipe 6 are respectively connected to the first drain port and the first inlet port.

[0029] In one specific implementation, the first drain pipe 6 can be a normally open drain pipe, that is, the first drain pipe 6 is not equipped with a drain valve for controlling the flow of cleaning fluid.

[0030] As a second specific implementation, the first drain pipe 6 is provided with a drain valve 12, which realizes the opening and closing of the first drain pipe 6 and controls the flow rate of the first drain pipe 6.

[0031] In this embodiment, the bottom of the inner tank 102 is provided with a second drain port, the buffer tank 8 is provided with a second inlet port, and the two ends of the second drain pipe 7 are respectively connected to the second drain port and the second inlet port.

[0032] In one embodiment, the bottom of the inner tank 102 is an inverted conical structure, and the second drain outlet is located at the top of the conical structure, so as to facilitate the drainage of the cleaning fluid in the inner tank 102.

[0033] In other embodiments, the bottom of the inner groove 102 may also be other structures, such as an inverted trapezoidal structure, etc., and this application does not impose specific restrictions on this.

[0034] In this embodiment, since the inner tank 102 also needs to be vented, the bottom of the inner tank 102 also needs to be provided with a corresponding vent, and an vent pipe is provided on the vent to discharge the gas in the inner tank 102 to the factory through the vent pipe.

[0035] In this embodiment, the vent can be located separately at the bottom of the inner tank 102. Of course, to reduce the number of openings at the bottom of the inner tank 102, the vent can also share a single outlet with the second drain outlet. The following detailed explanation uses the example of the vent and the second drain outlet sharing a single outlet.

[0036] In one specific implementation, a three-way valve 13 is provided on the second drain port. The three-way valve 13 may include a first valve port 1301, a second valve port 1302, and a third valve port 1303. The first valve port 1301 is connected to the inner tank 102, the second valve port 1302 is connected to the second drain pipe 7, and the third valve port 1303 is connected to the exhaust pipe. When the inner tank 102 needs to be drained, the three-way valve 13 is connected to the second drain pipe 7, that is, the first valve port 1301 and the second valve port 1302 of the three-way valve 13 are connected, and the first valve port 1301 and the third valve port 1303 are not connected. At this time, the inner tank 102 is connected to the second drain pipe 7, so the cleaning fluid in the inner tank 102 can be discharged into the storage tank through the second drain pipe 7. When the inner tank 102 has finished draining and needs to be vented, the three-way valve 13 is connected to the vent pipe, that is, the first valve port 1301 of the three-way valve 13 is connected to the third valve port 1303, and the first valve port 1301 of the three-way valve 13 is not connected to the second valve port 1302. At this time, the inner tank 102 can be vented through the vent pipe.

[0037] If the volume of buffer tank 8 is large enough to accommodate the cleaning fluid discharged from outer tank 101 and inner tank 102 during a single cleaning and drying process, then buffer tank 8 will not discharge any fluid as outer tank 101 and inner tank 102 discharge the cleaning fluid into buffer tank 8 through first drain pipe 6 and second drain pipe 7, respectively. If buffer tank 8 cannot accommodate the cleaning fluid discharged from outer tank 101 and inner tank 102 during a single cleaning and drying process, then buffer tank 8 needs to discharge the cleaning fluid into buffer tank 8 through first drain pipe 6 and second drain pipe 7, respectively. In other words, the discharge rate of buffer tank 8 needs to be less than the inflow rate of buffer tank 8. This is to prevent the buffer tank 8 from running out of liquid, thereby preventing the inability to reduce the negative pressure in first drain pipe 6 and second drain pipe 7.

[0038] In one specific implementation, the buffer tank 8 is also provided with a first liquid outlet, which is connected to the plant management end through a third drain pipe 9. During the process of the outer tank 101 and inner tank 102 discharging cleaning fluid into the buffer tank 8 through the first drain pipe 6 and the second drain pipe 7 respectively, the waste liquid in the buffer tank 8 is slowly discharged to the plant management end through the third drain pipe 9.

[0039] Furthermore, a valve may or may not be installed on the third drain pipe 9; this embodiment does not impose any specific restrictions on this.

[0040] In one specific implementation, a first valve is provided on the third drain pipe 9 to control the opening and closing of the third drain pipe 9 and the flow rate. If the inlet speed of the buffer tank 8 is less than the outlet speed, the first valve can be closed or its opening degree can be reduced so that the inlet speed of the buffer tank 8 is greater than the outlet speed.

[0041] If the drainage pressure inside buffer tank 8 is too high, at least one additional drainage pipeline for buffer tank 8 needs to be added. As a specific implementation, buffer tank 8 is also provided with a second outlet, which is connected to the plant maintenance department via a fourth drainage pipe 10.

[0042] Furthermore, a second valve 11 is provided on the fourth drain pipe 10 to control the opening and closing of the fourth drain pipe 10 and the flow rate. When the drainage pressure in the buffer tank 8 is not high, the second valve 11 is closed, and the waste liquid in the buffer tank 8 only needs to be discharged through the third drain pipe 9. When the drainage pressure in the buffer tank 8 is too high, the second valve 11 is opened, and the waste liquid in the buffer tank 8 is discharged through both the third drain pipe 9 and the fourth drain pipe 10. The degree to which the second valve 11 is opened can be adjusted according to the actual drainage pressure in the buffer tank 8, and this embodiment does not impose specific limitations on this.

[0043] This embodiment does not limit the specific types of the first valve and the second valve 11, such as ball valve, butterfly valve, etc.

[0044] In this embodiment, the space inside the inner tank 102 is a cleaning space. The bottom of the inner tank 102 is also provided with a liquid injection port. The cleaning liquid is injected into the inner tank 102 from the liquid injection port and fills the inner tank 102. Then, the excess cleaning liquid flows into the outer tank 101 from the opening of the inner tank 102.

[0045] This embodiment does not limit the specific type of cleaning solution, such as chemical solutions or deionized water. This embodiment preferably uses deionized water. By immersing the wafer 2 in the deionized water in the inner tank 102 for washing, contaminants such as organic matter, natural oxide layer, and metal ions attached to the surface of the wafer 2 can be removed.

[0046] As one embodiment, the inner side of the trough cover 3 is provided with a plurality of nozzles 4 facing the drying space 5. The nozzles 4 are connected to a gas source and are used to introduce drying gas into the drying space 5.

[0047] Optionally, the drying gas may include IPA (isopropanol) vapor, which is injected into the drying space 5 through nozzles 4 inside the tank cover 3. After the wafer is washed with deionized water in the cleaning space, it is immersed in the drying space 5 filled with IPA vapor. Due to the low surface tension and volatility of IPA, it can replace the moisture with high surface tension on the wafer surface. To accelerate the drying speed of the wafer surface, hot nitrogen gas is also injected through nozzles 4 inside the tank cover 3 to dry the IPA on the wafer surface, thereby achieving the effect of thoroughly drying the wafer.

[0048] The following combination Figure 1 and Figure 2 The working principle of the wafer cleaning and drying device is explained in detail.

[0049] First, deionized water is introduced into the inner tank 102 through the injection port at the bottom of the inner tank 102. The inner tank 102 is filled, and the excess deionized water overflows from the opening of the inner tank 102 into the outer tank 101. The outer tank 101 is discharged into the buffer tank 8 through the first drain pipe 6 at its bottom.

[0050] Next, the tank cover 3 is opened, and the wafer 2 is lowered into the inner tank 102 by the lifting mechanism so that the wafer 2 is completely immersed in deionized water. During this period, since deionized water is continuously injected into the inner tank 102, excess deionized water continuously flows from the opening of the inner tank 102 into the outer tank 101, and the first drain pipe 6 at the bottom of the outer tank 101 is in a normally open state.

[0051] Next, cover the tank with the cap 3, and the nozzle 4 inside the cap 3 begins to spray IPA vapor, which forms an IPA film on the surface of the deionized water.

[0052] Then, the lifting mechanism lifts the cleaned wafer 2 upwards. The IPA film adheres to the surface of wafer 2, detaches from the deionized water, and rises to the drying space 5. The deionized water in the inner tank 102 begins to drain into the buffer tank 8 through the second drain pipe 7. Wafer 2 is sprayed with IPA. Since the surface tension of IPA is much lower than that of deionized water, according to the Marangoni effect, the deionized water with higher surface tension will exert a pulling force on the surrounding IPA with lower surface tension. Therefore, the IPA will drive the deionized water on wafer 2 downwards, thus ensuring that there is no deionized water residue on the surface of wafer 2.

[0053] Finally, nozzle 4 sprays hot nitrogen gas onto wafer 2 to accelerate the evaporation rate of residual IPA on the surface of wafer 2, thereby achieving the effect of thoroughly drying wafer 2.

[0054] In summary, when draining liquid through the first drain pipe 6 and the second drain pipe 7, the negative pressure inside the tank 1 is approximately 70 Pa without the buffer tank 8; with the addition of the buffer tank 8, the negative pressure inside the tank 1 is approximately 30 Pa. Therefore, this invention reduces the negative pressure inside the tank 1 by adding the buffer tank 8, thus maintaining a stable gas atmosphere inside the tank 1 and improving the wafer drying effect.

[0055] Furthermore, the accumulation of particles at the bottom of the wafer is reduced, and the wafer's defect map or particle distribution map is significantly optimized.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wafer cleaning and drying apparatus, characterized in that, include: Tank body, tank cover, first drain pipe, second drain pipe, and buffer tank; The tank includes an inner tank and an outer tank. The outer tank is located outside the inner tank. The opening of the outer tank is higher than the opening of the inner tank, and the opening of the outer tank is connected to the opening of the inner tank. The inner tank is filled with cleaning fluid to clean the wafer. The tank cover is located at the top of the tank body, and a drying space is formed between the tank cover and the top of the inner tank. The drying space is filled with drying gas to dry the cleaned wafer. The first drain pipe is connected to the bottom of the outer tank, and the second drain pipe is connected to the bottom of the inner tank. Both the first drain pipe and the second drain pipe are connected to the buffer tank.

2. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The bottom of the outer tank has a first drain port, and the buffer tank has a first inlet port. The two ends of the first drain pipe are connected to the first drain port and the first inlet port, respectively.

3. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The bottom of the inner tank is provided with a second drain port, and the buffer tank is provided with a second inlet port. The two ends of the second drain pipe are respectively connected to the second drain port and the second inlet port.

4. The wafer cleaning and drying apparatus according to claim 3, characterized in that, The second drain port is equipped with a three-way valve, which includes a first valve port, a second valve port and a third valve port. The first valve port is connected to the inner tank, the second valve port is connected to the second drain pipe, and the third valve port is connected to the exhaust pipe.

5. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The buffer tank is also provided with a first liquid outlet, which is connected to the plant management end through a third drain pipe.

6. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The buffer tank is also provided with a second liquid outlet, which is connected to the plant terminal through a fourth drain pipe.

7. The wafer cleaning and drying apparatus according to claim 6, characterized in that, A valve is installed on the fourth drain pipe.

8. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The bottom of the inner tank is provided with an exhaust port, which is connected to an exhaust pipe for discharging dry gas from the inner tank.

9. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The bottom of the inner tank is provided with a liquid injection port for connecting a cleaning fluid injection pipe. The cleaning fluid is injected into the tank in sequence through the cleaning fluid injection pipe and the liquid injection port.

10. The wafer cleaning and drying apparatus according to claim 1, characterized in that, The inner side of the trough cover is provided with several nozzles facing the drying space. The nozzles are connected to a gas source and are used to introduce drying gas into the drying space.

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