Wafer cleaning equipment

Abstract

This application relates to a wafer cleaning apparatus. The wafer cleaning apparatus comprises a first cleaning tank, a second cleaning tank, a storage tank, a first heater, and a controller. The storage tank stores the SPM solution discharged from the second cleaning tank, and when the SPM solution is replaced in the first cleaning tank, the controller controls the storage tank to transport the SPM solution, which has been heated to a preset temperature range by the first heater, into the first cleaning tank. This solves the problem that tank-type or tank-type and monolithic SPM cleaning equipment cannot further conserve SPM solution, enabling the reuse of SPM solution and further saving of SPM solution.

Description

Technical Field

[0001] This application relates to the field of wafer cleaning, and particularly to a wafer cleaning apparatus.

Background Art

[0002] Conventional wafer cleaning facilities include monolithic SPM (a mixed solution of sulfuric acid and hydrogen peroxide) cleaning facilities and tank-type SPM cleaning facilities. Since the monolithic SPM cleaning facility cannot meet most processes when sulfuric acid and hydrogen peroxide are mixed, diluted, and then recovered and reused, the sulfuric acid consumption is much greater than that of the tank-type facility. Therefore, the monolithic SPM cleaning facility has a large SPM consumption, while the tank-type SPM cleaning facility has a small SPM consumption. In terms of particle removal, the tank-type SPM cleaning facility is inferior to the monolithic SPM cleaning facility, and there is a relatively large new increase in small particles. Generally, the tank-type SPM cleaning facility is suitable for the requirement of removing particles of 60 nm or more, and the monolithic SPM cleaning facility is suitable for the requirement of removing particles of 40 nm or less.

[0003] The cleaning facility combining tank-type and monolithic cleaning can save the SPM solution more than the monolithic SPM cleaning facility while ensuring the particle removal ability of 40 nm or less. However, as the process requirement progresses to removing particles of 26 nm or less, the conventional tank-type or tank-type and monolithic SPM cleaning facilities can no longer save the SPM solution further.

Summary of the Invention

[0004] Embodiments of this application provide a wafer cleaning apparatus that can further save sulfuric acid.

[0005] The wafer cleaning apparatus according to embodiments of this application includes a first cleaning tank for storing the SPM solution and performing the first cleaning of the wafer, a second cleaning tank for storing the SPM solution and performing the second cleaning of the wafer, After the wafer has been cleaned a second time in the second cleaning tank, a storage tank for storing the SPM solution discharged from the second cleaning tank is provided, A first heater for heating the SPM solution in the storage tank to a predetermined temperature range, The system includes a controller for controlling the storage tank so that, when replacing the SPM solution using the first washing tank, the SPM solution heated to a preset temperature range by the first heater is transported into the first washing tank.

[0006] In some embodiments of the present invention, the wafer cleaning apparatus further includes a concentration detector for detecting the concentration of the SPM solution in the storage tank and transmitting it to the controller when replacing the SPM solution with the first cleaning tank, and the controller compares the concentration of the SPM solution in the storage tank with a preset concentration, and controls the storage tank to transport the SPM solution heated to a preset temperature range by the first heater into the first cleaning tank if the concentration of the SPM solution in the storage tank does not become lower than the preset concentration.

[0007] In some embodiments of the present invention, the controller controls the storage tank to discharge the SPM solution from the storage tank when the concentration of the SPM solution in the storage tank falls below a preset concentration.

[0008] In some embodiments of the present invention, the wafer cleaning apparatus further comprises a first connecting conduit, the first cleaning tank comprising a first inner tank for storing SPM solution and a first outer tank for storing SPM solution overflowing from the first inner tank, and the first connecting conduit connects the first inner tank and the first outer tank.

[0009] In some embodiments of the present invention, a first cushion tank and a second heater are arranged in the first connecting pipeline, the first cushion tank is in communication with the first outer tank and further in communication with the first inner tank, and the second heater is arranged in the first connecting pipeline between the first cushion tank and the first inner tank.

[0010] In some embodiments of the present invention, a first filter is provided in the first connecting pipe, and the first filter is located between the first cushion tank and the second heater.

[0011] In some embodiments of the present invention, the wafer cleaning apparatus further comprises a second communication conduit, the second cleaning tank comprising a second inner tank for storing SPM solution and a second outer tank for storing SPM solution overflowing from the second inner tank, and the second communication conduit connects the second inner tank and the second outer tank.

[0012] In some embodiments of the present invention, the second connecting pipeline is provided with a second cushion tank and a third heater, the second cushion tank is in communication with the second outer tank and further in communication with the second inner tank, and the third heater is provided in the second connecting pipeline between the second cushion tank and the second inner tank.

[0013] In some embodiments of the present invention, a second filter is provided in the second communication pipeline, and the second filter is located between the second cushion tank and the third heater.

[0014] In some embodiments of the present invention, the invention further comprises at least one filter disposed between the first heater and the storage tank.

[0015] Based on the above, the wafer cleaning apparatus according to the embodiment of the present invention stores the SPM solution discharged from the second cleaning tank in a storage tank, and when replacing the SPM solution in the first cleaning tank, the controller controls the storage tank to transport the SPM solution, which has been heated to a preset temperature range by the first heater, into the first cleaning tank. This solves the problem that tank-type or tank-type and monolithic SPM cleaning equipment cannot further conserve SPM solution, enables the reuse of SPM solution, and further conserves SPM solution.

[0016] To make other features, purposes, and advantages of the present application easier to understand, details of one or more embodiments of the present application are shown in the following drawings and description. [Brief explanation of the drawing]

[0017] The features and performance of the present invention will be further described based on the following embodiments and their drawings. [Figure 1] This is a block diagram of the configuration of a wafer cleaning apparatus according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of the configuration of a wafer cleaning apparatus according to an embodiment of the present invention. [Modes for carrying out the invention]

[0018] To further clarify the purpose, technical proposal and advantages of this application, the application will be described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and not to limit the application. All other embodiments obtained by those skilled in the art without creative labor based on the embodiments herein are within the scope of protection of this application.

[0019] Unless otherwise defined, technical or scientific terms relating to this application should have the ordinary meaning understood by a person of general skill in the art to which this application pertains. Similar terms in this application, such as “one,” “one piece,” “one kind,” and “the said,” do not express quantitative limitations and may represent singular or plural. Terms in this application, such as “equip,” “include,” “possess,” and their variations, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus comprising a series of steps or modules (units) may not be limited to the listed steps or units, but may further include steps or units not listed, or other steps or units specific to those processes, methods, products, or apparatus. Similar terms in this application, such as “connected,” “joined,” and “joined,” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” in this application means two or more. "And / or" describes the correspondence between objects and indicates that three types of relationships exist. For example, "and / or" may indicate three cases: A exists alone, A and B exist simultaneously, and B exists alone. The terms "first," "second," "third," etc., used in this application are used solely to distinguish similar objects and do not represent a specific rank of the objects.

[0020] Embodiments of the present invention provide a wafer cleaning apparatus. Figure 1 is a block diagram of the configuration of a wafer cleaning apparatus according to an embodiment of the present invention. As shown in Figure 1, the wafer cleaning apparatus comprises a first cleaning tank 10, a second cleaning tank 20, a storage tank 30, a first heater 40, and a controller 50. The first cleaning tank 10 is for storing SPM solution and for performing the first cleaning of the wafer. The second cleaning tank 20 is for storing SPM solution and for performing the second cleaning of the wafer. The storage tank 30 is for storing the SPM solution discharged from the second cleaning tank 20. The first heater 40 is for heating the SPM solution in the storage tank 30 to a preset temperature range. The controller 50 controls the storage tank 30 so that when the SPM solution is replaced in the first cleaning tank 10, the SPM solution heated to a preset temperature range by the first heater 40 is transported into the first cleaning tank 10.

[0021] Typically, a wafer cleaning system is equipped with two SPM tanks. The first cleaning tank is used for the first cleaning of the wafer, so the SPM solution concentration is relatively low. The second cleaning tank is used for the second cleaning, which requires a higher degree of cleanliness than the first cleaning, so the amount of SPM solution consumed is less than in the first cleaning, and the SPM solution concentration is relatively higher. In conventional technology, when one cleaning tank reached its SPM solution replacement cycle, or when the number of processed wafers reached a preset number, all the SPM solution in both cleaning tanks was drained, and new SPM solution was replenished from the factory. On the other hand, the wafer cleaning system provided in this application drains the high-concentration SPM in the second cleaning tank 20 into the storage tank 30, and when the first cleaning tank 10 performs an SPM solution replacement, it supplies the SPM from the storage tank 30 to the first cleaning tank 10. This reduces the amount of SPM solution replenished from the factory, enables the reuse of high-concentration SPM solution, extends the usage cycle, and saves on the amount of SPM solution used.

[0022] Specifically, the SPM solution contains sulfuric acid and hydrogen peroxide. The amount of the SPM solution used in the embodiments of the present application can be understood as the amount of sulfuric acid in the SPM solution for conservation, as shown in Table 1 below. Here, the unit of sulfuric acid (H2SO4) in Table 1 is L, and the numbers in the table represent the number of wafers to be cleaned.

[0023]

Table 1

[0024] As can be seen from Table 1, when using the wafer cleaning apparatus according to the present application, in addition to the tank type / tank type and monolithic cleaning apparatuses of the prior art, sulfuric acid in the SPM solution can be further conserved.

[0025] In some of these embodiments, at least one filter may be further disposed between the first heater 40 and the storage tank 30 to filter the particles carried by the SPM solution discharged from the second cleaning tank 20.

[0026] In some embodiments, the replacement of the SPM solution in the first cleaning tank 10 and the second cleaning tank 20 may be synchronized. That is, when replacing the SPM solution, first synchronize the solution discharge, directly discharge the SPM solution in the first cleaning tank 10, discharge the SPM solution in the second cleaning tank 20 to the storage tank 30, and when adding a new SPM solution, add the solution in the storage tank 30 into the first cleaning tank 10 and add a new SPM solution into the second cleaning tank 20. By synchronizing the replacement of the SPM solution, the replacement efficiency of the SPM solution by the first cleaning tank 10 and the second cleaning tank 20 can be improved.

[0027] In some embodiments, the wafer cleaning apparatus further includes a concentration detector. When replacing the SPM solution in the first cleaning tank 10, the concentration detector detects the concentration of the SPM solution in the storage tank 30 and transmits this information to the controller 50. The controller 50 compares the concentration of the SPM solution in the storage tank 30 with a preset concentration. If the concentration of the SPM solution in the storage tank 30 does not fall below the preset concentration, the controller 50 controls the storage tank 30 to transport the SPM solution, heated to a preset temperature range by the first heater 40, into the first cleaning tank 10. By detecting the concentration of the SPM solution in the storage tank 30 using the concentration detector, it is possible to avoid the SPM solution concentration in the storage tank 30 being too low, which would affect the cleaning effect of the first cleaning tank 10. The preset concentration may be determined by process requirements.

[0028] As a means for the concentration detector to detect the concentration of the SPM solution, the SPM solution may be materialized by detecting the concentration of sulfuric acid in the SPM solution.

[0029] In some of these embodiments, the controller 50 controls the storage tank 30 to discharge the SPM solution when the concentration of the SPM solution in the storage tank 30 falls below a preset concentration.

[0030] Referring to Figure 2, in some of these embodiments, the wafer cleaning apparatus further comprises a first connecting conduit. The first cleaning tank 10 comprises a first inner tank 11 for storing SPM solution and a first outer tank 12 for storing SPM solution that overflows from the first inner tank 11. The first connecting conduit connects the first inner tank 11 and the first outer tank 12. In this embodiment, by connecting the first inner tank 11 and the first outer tank 12 with the first connecting conduit, the flow of liquid in the first cleaning tank 10 can be achieved, uniformity of solution concentration at each position in the first cleaning tank 10 can be ensured, and a better cleaning effect can be obtained.

[0031] Continuing to refer to Figure 2, the first connecting pipe contains a first cushion tank 13 and a second heater 14. The first cushion tank 13 is connected to the first outer tank 12 and further to the first inner tank 11, and the second heater 14 is located in the first connecting pipe between the first cushion tank 13 and the first inner tank 11. In this embodiment, by arranging the first cushion tank 13 in the first connecting pipe, the SPM solution in the first outer tank 12 can be buffered, and by arranging the second heater 14 in the first connecting pipe, the flowing SPM solution can be heated, improving the cleaning effect of the SPM solution. Furthermore, by arranging the first cushion tank 13, it is also possible to facilitate heating the flowing SPM solution with the second heater 14, and it is possible to avoid a situation where the flow rate of the SPM solution in the first connecting pipe becomes too fast, preventing the SPM solution from being heated to a preset temperature range and reducing the cleaning effect of the SPM solution.

[0032] As shown in Figure 2, the first connecting conduit is provided with one or more first filters 15 positioned between the first cushion tank 13 and the second heater 14. In this embodiment, the first filters 15 filter the flowing SPM solution, preventing the SPM solution from transporting particles during flow and affecting the subsequent wafer cleaning effect. To improve the filtration efficiency of the flowing SPM, the first filters 15 may be placed in each of the two conduits.

[0033] Referring to Figure 2, the wafer cleaning apparatus further includes a second connecting conduit. The second cleaning tank 20 comprises a second inner tank 21 for storing SPM solution and a second outer tank 22 for storing SPM solution that overflows from the second inner tank 21. The second connecting conduit connects the second inner tank 21 and the second outer tank 22. In this embodiment, by connecting the second inner tank 21 and the second outer tank 22 with the second connecting conduit, the flow of liquid in the second cleaning tank 20 can be achieved, ensuring uniformity of the solution concentration at each position in the second cleaning tank 20, and thus a better cleaning effect can be obtained.

[0034] Referring to Figure 2, a second cushion tank 23 and a third heater 24 are arranged in the second connecting pipeline. The second cushion tank 23 is connected to the second outer tank 22 and further to the second inner tank 21, and the third heater 24 is arranged in the second connecting pipeline between the second cushion tank 23 and the second inner tank 21. In this embodiment, by arranging the second cushion tank 23 in the second connecting pipeline, the SPM solution in the second outer tank 22 can be buffered, and by arranging the third heater 24 in the second connecting pipeline, the flowing SPM solution can be heated, improving the cleaning effect of the SPM solution. Furthermore, by arranging the second cushion tank 23, it is also possible to facilitate heating the flowing SPM solution with the third heater 24, and it is possible to avoid a situation where the flow velocity of the SPM solution in the second connecting pipeline becomes too fast, preventing the SPM solution from being heated to a preset temperature range and reducing the cleaning effect of the SPM solution.

[0035] As shown in Figure 2, the second communication conduit is further provided with one or more second filters 25 positioned between the second cushion tank 23 and the third heater 24. In this embodiment, the second filters 25 filter the SPM solution in flow, preventing the SPM solution from transporting particles during the flow process and affecting the subsequent cleaning effect of the wafer.

[0036] In some of these embodiments, the preset temperature range is 80°C to 100°C. In this embodiment, setting the preset temperature range to 80°C to 100°C can improve the cleaning effect of the SPM solution.

[0037] Continuing to refer to Figure 2, an additional three-way valve 60 may be provided in the second connecting pipeline to control the flow of the SPM solution. For example, when replacing the SPM solution, the second washing tank 20 and the storage tank 30 may be connected, and when the SPM solution is not being replaced, the second connecting pipeline may be connected to allow internal circulation of the second washing tank 20.

[0038] Those skilled in the art will understand that any combination of the technical features in the above embodiments is possible, and for the sake of brevity, not all combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features are inconsistent, they should be considered to fall within the scope described herein.

[0039] The embodiments described above represent several embodiments of the present application, and while their descriptions are relatively specific and detailed, this should not be understood as limiting the scope of the invention patent. Those skilled in the art should point out that several modifications and improvements can be made without departing from the concept of the present application, and all of these fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent should be in accordance with the attached claims.

Claims

1. A first cleaning tank for storing the SPM solution and for performing the first cleaning of the wafer, A second cleaning tank for storing the SPM solution and for performing a second cleaning of the wafer, After the wafer has been cleaned a second time in the second cleaning tank, a storage tank for storing the SPM solution discharged from the second cleaning tank is provided, A first heater for heating the SPM solution in the storage tank to a predetermined temperature range, When replacing the SPM solution using the first washing tank, a controller for controlling the storage tank is provided to transport the SPM solution, which has been heated to the preset temperature range by the first heater, into the first washing tank. A wafer cleaning apparatus characterized by comprising the following:

2. The wafer cleaning apparatus further includes a concentration detector for detecting the concentration of the SPM solution in the storage tank and transmitting it to the controller when replacing the SPM solution using the first cleaning tank. The wafer cleaning apparatus according to claim 1, characterized in that the controller controls the storage tank so as to transport the SPM solution heated to the preset temperature range by the first heater into the first cleaning tank when the concentration of the SPM solution in the storage tank does not become lower than the preset concentration when the concentration of the SPM solution in the storage tank does not become lower than the preset concentration.

3. The wafer cleaning apparatus according to claim 2, characterized in that the controller controls the storage tank to discharge the SPM solution from the storage tank when the concentration of the SPM solution in the storage tank becomes lower than the preset concentration.

4. The wafer cleaning apparatus further comprises a first connecting conduit, The first washing tank comprises a first inner tank for storing SPM solution and a first outer tank for storing SPM solution that overflows from the first inner tank. The wafer cleaning apparatus according to claim 1, characterized in that the first connecting conduit connects the first inner tank and the first outer tank.

5. The wafer cleaning apparatus according to claim 4, characterized in that a first cushion tank and a second heater are arranged in the first connecting conduit, the first cushion tank is in communication with the first outer tank and further in communication with the first inner tank, and the second heater is arranged in the first connecting conduit between the first cushion tank and the first inner tank.

6. The wafer cleaning apparatus according to claim 5, characterized in that a first filter is arranged in the first connecting conduit, and the first filter is arranged between the first cushion tank and the second heater.

7. The wafer cleaning apparatus further comprises a second communication conduit, The second washing tank comprises a second inner tank for storing SPM solution and a second outer tank for storing SPM solution that overflows from the second inner tank. The wafer cleaning apparatus according to claim 1, characterized in that the second connecting conduit connects the second inner tank and the second outer tank.

8. The wafer cleaning apparatus according to claim 7, characterized in that a second cushion tank and a third heater are arranged in the second connecting conduit, the second cushion tank is in communication with the second outer tank and further in communication with the second inner tank, and the third heater is arranged in the second connecting conduit between the second cushion tank and the second inner tank.

9. The wafer cleaning apparatus according to claim 8, characterized in that a second filter is arranged in the second connecting conduit, and the second filter is arranged between the second cushion tank and the third heater.

10. The wafer cleaning apparatus according to claim 1, further comprising at least one filter disposed between the first heater and the storage tank.

Images