Wafer cleaning and drying process, wafer dryer and its cleaning and drying structure assembly

Abstract

The present application discloses a wafer cleaning and drying process, a wafer dryer and its cleaning and drying structure assembly, which relates to the field of wafer cleaning equipment and can solve the problem of poor regulation accuracy in the prior art due to manual adjustment of electromagnetic pumps and valves with different calibers. The wafer dryer includes a main body and a lifting mechanism connected to the main body. The cleaning and drying structure assembly includes a drying tank body, a liquid inlet pipe, an IPA bubbling box, a first drain pipe and a controller; a tank cover is connected to the drying tank body at its own tank opening; the first drain pipe is connected to an electromagnetic pump, a first valve and a flow meter for measuring the liquid flow rate in the first drain pipe. Both the electromagnetic pump and the flow meter are electrically connected to the controller, so that the controller controls the flow rate of the electromagnetic pump according to the signal feedback of the liquid flow rate in the first drain pipe by the flow meter.

Description

Technical Field

[0001] The field involved in this application specifically relates to a wafer cleaning and drying process, a wafer dryer, and its cleaning and drying structure assembly. Background Art

[0002] In the process of wafer cleaning and drying, a Marangoni dryer is a commonly used device. The Marangoni effect it utilizes is a flow phenomenon based on the difference in liquid surface tension. When there is a difference in surface tension on the liquid surface layer, it will trigger the flow of the liquid. Through this effect, the residual water or solvent on the wafer surface can be effectively removed, achieving a dry effect without water marks and pollution.

[0003] In a typical wafer cleaning and drying process, the wafer is first immersed in the cleaning liquid in the drying tank for preliminary cleaning. Subsequently, IPA (isopropyl alcohol) gas is introduced into the drying tank to form an IPA gas environment above the water surface. With the slow drainage operation, the wafer gradually separates from the water surface. Since the surface tension of IPA is much smaller than that of water, a surface tension gradient will be generated on the surface layer of the sloping water flow, resulting in the occurrence of Marangoni convection. At this time, the water is "sucked back" to the water surface, thereby effectively removing the water on the wafer surface, achieving a dry effect, ensuring that there is no water mark residue on the wafer surface, and meeting the requirements of high cleanliness.

[0004] However, in the prior art, in order to control the drainage speed of the drying tank, an electromagnetic pump and multiple valves with different diameters are usually installed on the drain pipe connected to the drying tank, and the opening and closing of these valves are manually adjusted to precisely control the drainage speed. Because the accuracy of manual adjustment is difficult to meet the ideal requirements, the drainage speed is difficult to precisely control, which in turn affects the stability of the drying effect. In addition, this design also increases the operation complexity and places higher requirements on the technical level of the operators. Summary of the Invention

[0005] Therefore, this application provides a wafer cleaning and drying process, a wafer dryer, and its cleaning and drying structure assembly to solve the problem of poor regulation accuracy in the prior art when the electromagnetic pump and multiple valves with different diameters are adjusted manually.

[0006] To achieve the above object, this application provides the following technical solutions:

[0007] A cleaning and drying structure assembly of a wafer dryer. The wafer dryer includes a main body and a lifting mechanism connected to the main body and used for lifting a wafer cassette. The cleaning and drying structure assembly includes a drying tank body connected to the main body, a liquid inlet pipe connected to the drying tank body and used for injecting cleaning liquid into the drying tank body, an IPA bubbling box connected to the drying tank body and used for injecting isopropyl alcohol vapor into the drying tank body, a first drain pipe connected to the drying tank body and used for discharging the cleaning liquid in the drying tank body, and a controller connected to the main body;

[0008] A tank cover for sealing the tank opening is connected to the drying tank body at its tank opening;

[0009] The first drain pipe is connected with an electromagnetic pump, a first valve and a flowmeter for measuring the liquid flow rate in the first drain pipe. Both the electromagnetic pump and the flowmeter are electrically connected to the controller, so that the controller controls the flow rate of the electromagnetic pump according to the signal feedback of the flowmeter on the liquid flow rate in the first drain pipe.

[0010] Optionally, the drying tank body includes a first tank body connected to the main body and a second tank body connected to the outer wall of the top of the first tank body. An overflow tank is formed between the outer walls of the second tank body and the first tank body, so that the cleaning liquid overflowing from the first tank body flows into the overflow tank. A second drain pipe is connected to the bottom of the overflow tank;

[0011] The liquid inlet pipe is connected to the side wall of the first tank body, the first drain pipe is connected to the bottom wall of the first tank body, the IPA bubbling box is connected to the side wall of the second tank body, and the opening of the IPA bubbling box is higher than the opening of the first tank body. The tank cover is connected to the opening of the second tank body.

[0012] Optionally, a first nitrogen pipe for filling nitrogen into the IPA bubbling box is connected to the side wall of the IPA bubbling box. Nitrogen bubbles in the IPA bubbling box to evaporate the IPA solution into the drying tank body.

[0013] Optionally, a liquid storage tank for storing IPA solution is connected to the main body. The liquid storage tank is connected with a first pipeline for supplying IPA solution to the IPA bubbling box. The liquid storage tank is also connected with a second pipeline for discharging the IPA solution in the IPA bubbling box back into the liquid storage tank. An IPA stock solution barrel is connected to the outside of the main body, and a third pipeline is connected between the IPA stock solution barrel and the first pipeline to supplement IPA solution to the liquid storage tank;

[0014] The first pipeline and the second pipeline cooperate to keep the liquid level height in the IPA bubbling box at a set height.

[0015] Optionally, the second pipeline is connected with a second valve. Between the liquid storage tank and the IPA bubbling box, the first pipeline is successively connected with a third valve, an air bladder pump, a fourth valve, and a fifth valve. The third valve is located between the liquid storage tank and the third pipeline. The air bladder pump, the fourth valve, and the fifth valve are located between the third pipeline and the IPA bubbling box. The third pipeline is connected with a sixth valve;

[0016] A fourth pipeline is connected between the first pipeline and the liquid storage tank. The fourth pipeline is connected with a seventh valve. The first pipeline is connected with a filter. A fifth pipeline is connected between the filter and the liquid storage tank. The fifth pipeline is connected with an eighth valve.

[0017] Optionally, the first drain pipe includes a first section connected to the first tank body, a second section connected to one end of the first section away from the first tank body, and a third section connected to one end of the second section away from the first section and used for discharging the cleaning liquid in the first tank body to the outside of the main body. The electromagnetic pump, the first valve, and the flowmeter are connected to the second section. The first drain pipe is connected with a sixth pipeline. One end of the sixth pipeline is connected to the junction of the first section and the second section, and the other end is connected to the junction of the second section and the third section. The sixth pipeline is connected with a ninth valve.

[0018] Optionally, the highest point of the second section is higher than the notch of the first tank body.

[0019] Optionally, the inner diameter of the third section gradually increases from the end close to the second section to the end of the third section.

[0020] Optionally, one end of the first nitrogen pipe away from the IPA bubbling box is connected with a gas supply pipe for supplying nitrogen. A second nitrogen pipe is connected between the gas supply pipe and the tank cover. The tank cover is connected with a plurality of nitrogen nozzles connected to the second nitrogen pipe. The second nitrogen pipe is connected with a tenth valve and a gas online heater. The first nitrogen pipe is connected with an eleventh valve.

[0021] Optionally, the liquid inlet pipe is connected with a twelfth valve. The liquid inlet pipe is connected with a seventh pipeline. The seventh pipeline is connected with a thirteenth valve in parallel with the twelfth valve. The diameter of the thirteenth valve is smaller than that of the twelfth valve.

[0022] This application discloses a wafer dryer, including the cleaning and drying structure assembly of the wafer dryer as described above.

[0023] This application also discloses a wafer cleaning and drying process, including the following steps:

[0024] S1. Standby state before wafer cleaning: The thirteenth valve is open, the twelfth valve is closed, the liquid inlet pipe slowly injects cleaning liquid into the first tank, the cleaning liquid in the first tank is in a full water slow overflow state, and the overflowing cleaning liquid enters the overflow tank and is discharged through the second drain pipe and the third section. The lifting height of the lifting mechanism is at point A, the tank cover is in the closed state, the tenth valve on the second nitrogen pipe is open, and multiple nitrogen nozzles on the tank cover blow nitrogen into the drying tank;

[0025] S2. Wafer cleaning: The tenth valve on the second nitrogen pipe is closed, and multiple nitrogen nozzles on the tank cover stop blowing nitrogen into the drying tank. The tank cover is opened, the lifting mechanism is lifted to point B, the wafer cassette is placed on the lifting mechanism, and the lifting mechanism descends to point C. Multiple wafers in the wafer cassette are immersed in the cleaning liquid in the first tank and are supported by the wafer support in the drying tank. The tank cover is closed. The twelfth valve on the liquid inlet pipe is opened, and the liquid inlet pipe quickly injects cleaning liquid into the first tank. The cleaning liquid in the first tank is in a full water fast overflow state. The fifth valve and the second valve are opened, and the storage tank supplies IPA solution to the IPA bubbling tank through the first pipeline. When the liquid level of the IPA solution in the IPA bubbling tank is higher than the pipe orifice of the second pipeline, the IPA solution in the IPA bubbling tank flows back to the storage tank through the second pipeline. After that, the twelfth valve and the thirteenth valve are closed, the liquid inlet pipe stops injecting cleaning liquid into the first tank, the eleventh valve is opened, and the first nitrogen pipe fills the IPA bubbling tank with nitrogen to form nitrogen bubbles in the IPA solution in the IPA bubbling tank, and evaporates the IPA into the drying tank;

[0026] S3. Slow drainage: After the first nitrogen pipe continuously fills the IPA bubbling tank with nitrogen for a set time, the first valve and the electromagnetic pump are opened, the ninth valve is closed, and the first drain pipe starts slow drainage. The cleaning liquid in the first tank is discharged successively through the first section, the second section and the third section. When the liquid level of the cleaning liquid drops to expose the wafers by a set height, the wafer chuck rotates and abuts against the tops of the multiple wafers, and cooperates with the wafer support to constrain the postures and positions of the multiple wafers. The lifting mechanism slowly descends to point D, the multiple wafers are separated from the wafer cassette, and the wafer cassette is supported at the bottom of the wafer support. When the liquid level of the cleaning liquid continues to drop below the wafer cassette, the eleventh valve is closed, the first nitrogen pipe stops filling the IPA bubbling tank with nitrogen, the first valve and the electromagnetic pump are closed, and the slow drainage of the first drain pipe stops. The air bladder pump, the third valve, the fourth valve and the second valve are closed, and the IPA stock solution barrel and the storage tank stop injecting IPA solution into the IPA bubbling tank. The fifth valve and the seventh valve are opened, and the IPA solution in the IPA bubbling tank flows back to the storage tank through the second pipeline;

[0027] S4. Quick drainage: Close the first valve and open the ninth valve to quickly drain the cleaning liquid through the first section, the sixth pipeline, and the third section. Raise the lifting mechanism to point C, rotate the wafer chuck to return to its original position. After all the cleaning liquid in the first tank is drained, close the ninth valve after a set time.

[0028] S5. Wafer drying: Open the tenth valve. The gas supply pipe and the second nitrogen pipe supply nitrogen to multiple nitrogen nozzles on the tank cover, and at the same time, turn on the gas online heater to heat the nitrogen, so that the hot nitrogen ejected from the multiple nitrogen nozzles dries the wafer and the wafer cassette. After drying for a set time, open the tank cover, raise the lifting mechanism to point A, turn off the gas online heater, and the gas supply pipe and the second nitrogen pipe continue to supply nitrogen to the multiple nitrogen nozzles on the tank cover at a small flow rate. All the IPA solution in the IPA bubbling tank flows back to the liquid storage tank.

[0029] S6. Process end: Close the tenth valve, stop supplying nitrogen to the multiple nitrogen nozzles on the tank cover by the gas supply pipe and the second nitrogen pipe, close the tank cover, raise the lifting mechanism to point B, open the thirteenth valve, slowly inject cleaning liquid into the first tank through the liquid inlet pipe, remove the wafer cassette on the lifting mechanism. After the liquid level of the cleaning liquid in the first tank reaches the specified position, open the twelfth valve, and start to quickly inject cleaning liquid into the first tank through the liquid inlet pipe. After the liquid level of the cleaning liquid in the first tank reaches the specified position, close the twelfth valve, and slowly inject cleaning liquid into the first tank to make the cleaning liquid in the first tank in a full water slow overflow state.

[0030] The lifting height points of the lifting mechanism from high to low are: point B, point A, point C, point D.

[0031] Compared with the prior art, the present application has at least the following beneficial effects:

[0032] During the cleaning process of the wafer, the lifting mechanism lifts the wafer cassette carrying multiple wafers into the drying tank or takes it out of the drying tank. When the wafer cassette and the wafers are immersed in the cleaning liquid in the drying tank and start to be cleaned, the IPA bubbling tank injects isopropyl alcohol vapor into the drying tank. At the same time, the cleaning liquid in the drying tank starts to be discharged through the first drain pipe. Open the first valve, and the flowmeter monitors the flow rate of the cleaning liquid in the first drain pipe in real time and feeds the data back to the controller. The controller automatically adjusts the flow rate of the electromagnetic pump according to the feedback information to achieve precise control of the cleaning liquid discharge speed. Compared with the prior art where multiple valves need to be manually adjusted to control the drainage speed, the present application adopts an automated control method, which can improve the operation convenience, ensure the accuracy and stability of the discharge speed, avoid errors caused by manual adjustment, and thus improve the cleaning effect and the stability of the subsequent drying process. Description of the Drawings

[0033] To more intuitively illustrate the prior art and the present application, several exemplary drawings are given below. It should be understood that the specific shapes and structures shown in the drawings generally should not be regarded as limiting conditions when implementing the present application; for example, those skilled in the art are capable of making routine adjustments or further optimizations to the addition / deletion / attribution division, specific shapes, positional relationships, connection methods, dimensional proportional relationships, etc. of certain units (components) based on the technical concepts disclosed in the present application and the exemplary drawings.

[0034] Figure 1 Pipeline schematic diagram of the cleaning and drying structure assembly of a wafer dryer provided in an embodiment of the present application;

[0035] Figure 2 For Figure 1 Enlarged view of part A of

[0036] Figure 3 For Figure 1 Enlarged view of part B of

[0037] Figure 4 For Figure 1 Enlarged view of part C of

[0038] Figure 5 For Figure 1 Enlarged view of part D of

[0039] Figure 6 Partial structure schematic diagram of a wafer dryer provided in an embodiment of the present application;

[0040] Figure 7 Cooperation schematic diagram of the drying tank body and the lifting mechanism provided in an embodiment of the present application;

[0041] Figure 8 For Figure 7 Partial structure schematic diagram of

[0042] Figure 9 Structure schematic diagram of the drying tank body provided in an embodiment of the present application;

[0043] Figure 10 For Figure 6 Partial structure schematic diagram of

[0044] Figure 11 For Figure 10 Partial structure schematic diagram of

[0045] Figure 12 For Figure 11 Partial structure cross-sectional view along the a-a direction.

[0046] Explanation of reference numerals:

[0047] 1. Drying tank body; 11. First tank body; 12. Second tank body; 121. Overflow tank; 13. IPA bubbling box; 14. Tank cover; 141. Nitrogen nozzle; 15. Wafer chuck; 16. Wafer support; 2. Lifting mechanism; 3. Wafer cassette; 31. Wafer; 4. First drain pipe; 41. First section; 42. Second section; 421. First valve; 422. Electromagnetic pump; 423. Flowmeter; 43. Third section; 44. Sixth pipe; 441. Ninth valve; 5. Second drain pipe; 6. Liquid inlet pipe; 61. Seventh pipe; 62. Thirteenth valve; 63. Twelfth valve; 7. First pipe; 71. Third pipe; 711. Sixth valve; 72. Third valve; 73. Air bladder pump; 74. Fourth valve; 75. Fifth valve; 76. Fifth pipe; 761. Eighth valve; 77. Fourth pipe; 771. Seventh valve; 78. Filter; 8. Second pipe; 81. Second valve; 9. Gas supply pipe; 91. First nitrogen pipe; 911. Eleventh valve; 92. Second nitrogen pipe; 921. Tenth valve; 922. Gas online heater; 10. Liquid storage tank; 101. Main body; 102. IPA stock solution barrel. Detailed implementation manners

[0048] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] In the description of the present application: Unless otherwise specified, "a plurality of" means two or more. Terms such as "first", "second", "third", etc. in the present application are intended to distinguish the objects being referred to and do not have special significance in terms of technical connotations (for example, they should not be understood as emphasizing importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0050] Refer to Figure 1-7 , the present application discloses a cleaning and drying structure assembly of a wafer dryer. The wafer dryer includes a main body 101 and a lifting mechanism 2 connected to the main body 101 and used for lifting the wafer cassette 3. The cleaning and drying structure assembly includes a drying tank body 1 connected to the main body 101, a liquid inlet pipe 6 connected to the drying tank body 1 and used for injecting a cleaning liquid into the drying tank body 1, an IPA bubbling box 13 connected to the drying tank body 1 and used for injecting isopropyl alcohol vapor into the drying tank body 1, a first drain pipe 4 connected to the drying tank body 1 and used for discharging the cleaning liquid in the drying tank body 1, and a controller connected to the main body 101;

[0051] A tank cover 14 for sealing the tank opening of the drying tank body 1 is connected to the drying tank body 1 at its own tank opening;

[0052] The first drain pipe 4 is connected to an electromagnetic pump 422, a first valve 421, and a flow meter 423 for measuring the liquid flow rate in the first drain pipe 4. Both the electromagnetic pump 422 and the flow meter 423 are electrically connected to the controller, so that the controller controls the flow rate of the electromagnetic pump 422 according to the signal feedback of the liquid flow rate in the first drain pipe 4 by the flow meter 423.

[0053] During the cleaning process of the wafers 31, the lifting mechanism 2 lifts the wafer cassette 3 carrying multiple wafers 31 into the drying tank body 1, or takes it out of the drying tank body 1. When the wafer cassette 3 and the wafers 31 are immersed in the cleaning liquid in the drying tank body 1 and start to be cleaned, the IPA bubbling box 13 injects isopropyl alcohol vapor into the drying tank body 1. At the same time, the cleaning liquid in the drying tank body 1 starts to be drained through the first drain pipe 4. The first valve 421 is opened, and the flow meter 423 monitors the flow rate of the cleaning liquid in the first drain pipe 4 in real time and feeds the data back to the controller. The controller automatically adjusts the flow rate of the electromagnetic pump 422 according to the feedback information to achieve precise control of the cleaning liquid drainage speed. Compared with the prior art that requires manual adjustment of multiple valves to control the drainage speed, the present application adopts an automated control method, which can improve the operation convenience, ensure the accuracy and stability of the drainage speed, avoid the errors caused by manual adjustment, and thus improve the cleaning effect and the stability of the subsequent drying process.

[0054] It should be noted that the wafer dryer, the lifting mechanism 2, the electromagnetic pump, the flow meter, and the controller are prior arts and are not described in detail in the present application. It should be added that slow drainage means that by precisely controlling the drainage speed, the liquid level in the drying tank body 1 slowly drops. This control method can keep the contact time between the liquid level and the surface of the wafers 31 appropriate and avoid the influence of too fast water flow on the cleaning effect.

[0055] In some embodiments, the controller can be a frequency converter.

[0056] Reference Figure 7-12 , the drying tank body 1 includes a first tank body 11 connected to the main body 101 and a second tank body 12 connected to the top outer wall of the first tank body 11. An overflow tank 121 is formed between the outer walls of the second tank body 12 and the first tank body 11, so that the cleaning liquid overflowing from the first tank body 11 flows into the overflow tank 121. The bottom of the overflow tank 121 is connected to a second drain pipe 5;

[0057] The liquid inlet pipe 6 is connected to the side wall of the first tank body 11, the first drain pipe 4 is connected to the bottom wall of the first tank body 11, the IPA bubbling box 13 is connected to the side wall of the second tank body 12, and the mouth of the IPA bubbling box 13 is higher than the mouth of the first tank body 11. The tank cover 14 is connected to the mouth of the second tank body 12.

[0058] During the cleaning and drying process, the cleaning liquid is injected into the first tank body 11 through the liquid inlet pipe 6 and gradually fills the entire tank body. When the liquid level of the cleaning liquid reaches the notch of the first tank body 11, the excess cleaning liquid will overflow into the overflow tank 121, thereby realizing the overflow discharge of the cleaning liquid in the first tank body 11. The cleaning liquid in the overflow tank 121 is then discharged through the second drain pipe 5. Through this design, the cleaning liquid in the first tank body 11 can be kept in a continuous flowing and replacing state, so as to effectively carry away the suspended particles and impurities in the tank body and maintain the cleanliness of the liquid in the tank. Especially when the tank cover 14 is opened, external particles or impurities in the air may enter the drying tank body 1, and this overflow discharge method can effectively discharge these particles and impurities from the overflow tank 121, preventing them from staying in the drying tank body 1 and affecting the cleanliness and drying effect of the wafer 31.

[0059] In some embodiments, there are two IPA bubbling boxes 13, and the two IPA bubbling boxes 13 are located on opposite sides of the second tank body 12.

[0060] The side wall of the IPA bubbling box 13 is connected with a first nitrogen pipe 91 for filling nitrogen into the IPA bubbling box 13. The nitrogen bubbles in the IPA bubbling box 13 to evaporate the IPA solution into the drying tank body 1. The first nitrogen pipe 91 continuously fills nitrogen into the IPA bubbling box 13, and the nitrogen forms bubbles in the IPA solution in the IPA bubbling box 13. The bubbles will continuously disturb the surface of the IPA liquid, thereby increasing the contact area between the IPA liquid and the air. This bubble disturbance speeds up the evaporation rate of the IPA, and can generate and transfer the IPA vapor to the drying tank body 1 more quickly, forming the required IPA gas environment in the drying tank body 1.

[0061] The main body 101 is connected with a liquid storage tank 10 for storing the IPA solution. The liquid storage tank 10 is connected with a first pipeline 7 for supplying the IPA solution to the IPA bubbling box 13. The liquid storage tank 10 is also connected with a second pipeline 8 for discharging the IPA solution in the IPA bubbling box 13 back into the liquid storage tank 10. The main body 101 is connected with an IPA stock solution barrel 102 outside itself, and a third pipeline 71 is connected between the IPA stock solution barrel 102 and the first pipeline 7 to supplement the IPA solution to the liquid storage tank 10;

[0062] The first pipeline 7 and the second pipeline 8 cooperate to maintain the liquid level height in the IPA bubbling box 13 at a set height.

[0063] During the process that the IPA solution in the IPA bubbling tank 13 gradually evaporates and enters the drying tank body 1, the liquid level of the IPA solution will gradually decrease. To maintain the stability of the liquid level in the IPA bubbling tank 13, the IPA stock solution barrel 102 supplies the IPA solution to the liquid storage tank 10 through the third pipeline 71, and the liquid storage tank 10 replenishes the IPA solution to the IPA bubbling tank 13 through the first pipeline 7. Moreover, the first pipeline 7 and the second pipeline 8 cooperate to enable the IPA solution to circulate between the liquid storage tank 10 and the IPA bubbling tank 13, maintaining the liquid level of the IPA solution in the IPA bubbling tank 13 at a preset height, ensuring that the liquid level of the IPA solution in the IPA bubbling tank 13 is at the optimal height to produce an ideal bubbling effect.

[0064] The second pipeline 8 is connected with a second valve 81. Between the liquid storage tank 10 and the IPA bubbling tank 13, the first pipeline 7 is successively connected with a third valve 72, an air bladder pump 73, a fourth valve 74, and a fifth valve 75. The third valve 72 is located between the liquid storage tank 10 and the third pipeline 71, and the air bladder pump 73, the fourth valve 74, and the fifth valve 75 are located between the third pipeline 71 and the IPA bubbling tank 13. The third pipeline 71 is connected with a sixth valve 711;

[0065] A fourth pipeline 77 is connected between the first pipeline 7 and the liquid storage tank 10. The fourth pipeline 77 is connected with a seventh valve 771. The first pipeline 7 is connected with a filter 78. A fifth pipeline 76 is connected between the filter 78 and the liquid storage tank 10. The fifth pipeline 76 is connected with an eighth valve 761.

[0066] The opening and closing of the corresponding pipelines are controlled by the second, third, fourth, fifth, sixth, seventh, and eighth valves to achieve precise management of the flow path of the IPA solution. The air bladder pump 73 is used to control the flow rate of the IPA solution supplied to the IPA bubbling tank 13.

[0067] In addition, a filter 78 is installed in the first pipeline 7 to filter impurities in the IPA solution and ensure the cleanliness of the IPA solution entering the IPA bubbling tank 13. To prevent the accumulation of gas in the filter 78 from affecting the filtration efficiency, the eighth valve 761 is designed to automatically open for 1 second every 5 seconds, discharging the accumulated gas in the filter 78 into the liquid storage tank 10, effectively preventing the filter 78 from being "choked" due to gas accumulation.

[0068] The first drain pipe 4 includes a first section 41 connected to the first tank 11, a second section 42 connected to one end of the first section 41 away from the first tank 11, and a third section 43 connected to one end of the second section 42 away from the first section 41 and used to drain the cleaning liquid in the first tank 11 to the outside of the main body 101. The electromagnetic pump 422, the first valve 421, and the flow meter 423 are connected to the second section 42. The first drain pipe 4 is connected with a sixth pipe 44. One end of the sixth pipe 44 is connected to the intersection of the first section 41 and the second section 42, and the other end is connected to the intersection of the second section 42 and the third section 43. The sixth pipe 44 is connected with a ninth valve 441.

[0069] During the cleaning and drying process, when the liquid level of the cleaning liquid in the first tank 11 gradually drops below the wafer 31 and the wafer cassette 3, the slow drainage process stops. At this time, the controller closes the electromagnetic pump 422 and the first valve 421 to terminate the slow drainage process of the first drain pipe 4. Then, the ninth valve 441 on the sixth pipe 44 is opened, so that the cleaning liquid in the first tank 11 quickly flows through the first section 41 and the sixth pipe 44 to the third section 43 and is finally discharged outside the main body 101, enabling the cleaning liquid to be quickly discharged from the first tank 11, thereby saving time and improving the cleaning and drying efficiency.

[0070] In some embodiments, one end of the second drain pipe 5 away from the second tank 12 is connected to the third section 43, so that the cleaning liquid in the overflow tank 121 can be discharged through the second drain pipe 5 and the third section 43.

[0071] The highest point of the second section 42 is higher than the notch of the first tank 11.

[0072] Since the first drain pipe 4 is connected to the bottom of the first tank 11, the cleaning liquid flows into the first drain pipe 4 under the action of gravity, which results in an unstable drainage rate: when the water level in the tank is high, the drainage rate is fast; as the water level drops, the drainage rate gradually slows down. To solve this problem, in the design of this application, a part of the second section 42 of the first drain pipe 4 is raised so that its highest point is higher than the notch of the first tank 11. Through this design, the cleaning liquid will encounter the high point of the second section 42 during the discharge process, and this height difference can offset the direct influence of gravity on the drainage rate to a certain extent.

[0073] The inner diameter of the third section 43 gradually increases from the end close to the second section 42 to the end of the third section 43.

[0074] At the beginning of slow drainage, since the first drain pipe 4 may be filled with cleaning liquid, a siphon phenomenon is formed, and the cleaning liquid will be quickly sucked out under the siphon effect without being controlled by the electromagnetic pump. This phenomenon will cause large fluctuations in the drainage speed, which will in turn affect the uniformity and effect of the drying process, and may cause poor drying problems on the surface of the wafer 31; to solve this problem, the inner diameter of the third section 43 in the design of the present application gradually increases from one end close to the second section 42 to the tail end. Through the design of gradually increasing the inner diameter, the liquid in the pipeline will not fill the entire pipeline cross-section during the drainage process, avoiding the formation of a siphon phenomenon.

[0075] One end of the first nitrogen pipe 91 away from the IPA bubbling box 13 is connected to a gas supply pipe 9 for providing nitrogen, a second nitrogen pipe 92 is connected between the gas supply pipe 9 and the tank cover 14, the tank cover 14 is connected to a plurality of nitrogen nozzles 141 connected to the second nitrogen pipe 92, the second nitrogen pipe 92 is connected to a tenth valve 921 and a gas online heater 922, and the first nitrogen pipe 91 is connected to an eleventh valve 911.

[0076] In the cleaning and drying structure of the present application, the second nitrogen pipe 92 delivers nitrogen to the multiple nitrogen nozzles 141 of the tank cover 14, and the nitrogen is heated by the gas online heater 922. After cleaning, the heated nitrogen is sprayed through the nozzle to the multiple wafers 31 and the surface of the wafer box 3 in the drying tank body 1, thereby heating and drying the wafers 31. The heated nitrogen can quickly take away the trace moisture remaining on the surface of the wafer 31, and can also effectively reduce the retention of moisture in the first tank body 11, ensuring that the drying process is thorough and without water marks.

[0077] In some embodiments, the gas supply pipe 9 can be connected to a valve, a flow controller, a filter 78, a flow meter 423, etc.

[0078] The liquid inlet pipe 6 is connected to a twelfth valve 63 , the liquid inlet pipe 6 is connected to a seventh pipeline 61 , the seventh pipeline 61 is connected to a thirteenth valve 62 in parallel with the twelfth valve 63 , and the diameter of the thirteenth valve 62 is smaller than that of the twelfth valve 63 .

[0079] The thirteenth valve 62 has a smaller diameter and is used to control slow water injection, so that it is used when the cleaning liquid needs to be slowly and steadily injected into the first tank body 11. This ensures that the cleaning liquid enters the tank body smoothly and avoids liquid level fluctuations caused by too fast water injection. Especially in sensitive cleaning or drying stages, the rate of liquid level rise can be effectively controlled. The twelfth valve 63 has a larger diameter and is used for fast water injection, so that the tank body can be quickly filled at the beginning of the cleaning cycle, shortening the preparation time and improving the cleaning efficiency. Through the combination of these two valves with different diameters, the present application realizes flexible control of the water injection rate, which can achieve fine control by slow water injection in specific cleaning steps, and can also improve efficiency by fast water injection in the system preparation stage.

[0080] This application discloses a wafer dryer, including the cleaning and drying structure assembly of the wafer dryer as described above.

[0081] Reference Figure 1-12 , this application also discloses a wafer cleaning and drying process, including the following steps:

[0082] S1. Standby state before wafer 31 cleaning: The thirteenth valve 62 is opened, the twelfth valve 63 is closed, the liquid inlet pipe 6 slowly injects cleaning liquid into the first tank 11, the cleaning liquid in the first tank 11 is in a full-water slow-overflow state, the overflowing cleaning liquid enters the overflow tank 121 and is discharged through the second drain pipe 5 and the third section 43, so that the cleaning liquid in the first tank 11 is in a flowing state, removing the residual particles in the first tank 11. The lifting height of the lifting mechanism 2 is at point A, the tank cover 14 is in a closed state, the tenth valve 921 on the second nitrogen pipe 92 is opened, and multiple nitrogen nozzles 141 on the tank cover 14 blow nitrogen into the drying tank body 1;

[0083] Before wafer cleaning, the liquid level of the IPA solution in the liquid storage tank 10 is detected. When the liquid level of the IPA solution is lower than the M liquid level (working liquid level), the air bladder pump 73, the sixth valve 711, the fourth valve 74, and the seventh valve 771 need to be opened, and the IPA stock solution barrel 102 replenishes the IPA solution in the liquid storage tank 10 until the liquid level reaches the M liquid level (working liquid level); at the same time, the liquid level of the cleaning liquid in the first tank 11 is also detected to ensure that the liquid level of the cleaning liquid in the first tank 11 is in a full-tank state; and to ensure the subsequent nitrogen drying effect, the temperature at the nitrogen nozzle is detected. When the set temperature is not reached, the tenth valve 921 and the gas in-line heater 922 need to be opened to preheat the second nitrogen pipe 92.

[0084] S2. Cleaning of the wafer 31: The tenth valve 921 on the second nitrogen pipe 92 is closed, and the multiple nitrogen nozzles 141 on the tank cover 14 stop blowing nitrogen into the drying tank body 1. The tank cover 14 is opened, the lifting mechanism 2 is lifted to point B, the wafer cassette 3 is placed on the lifting mechanism 2, and then the lifting mechanism 2 descends to point C. The multiple wafers 31 in the wafer cassette 3 are immersed in the cleaning liquid in the first tank body 11 and are supported by the wafer support 16 in the drying tank body 1. The tank cover 14 is closed; wherein, the wafer support 16 is a prior art, and during the descent of the wafer cassette 3, the wafer support 16 can support the multiple wafers 31; the twelfth valve 63 on the liquid inlet pipe 6 is opened, and the liquid inlet pipe 6 quickly injects the cleaning liquid into the first tank body 11. The cleaning liquid in the first tank body 11 is in a state of being full and about to overflow. The fifth valve 75 and the second valve 81 are opened, and the storage tank 10 supplies the IPA solution to the IPA bubbling tank 13 through the first pipe 7. When the liquid level of the IPA solution in the IPA bubbling tank 13 is higher than the pipe orifice of the second pipe 8, the IPA solution in the IPA bubbling tank 13 flows back to the storage tank 10 through the second pipe 8. After that, the twelfth valve 63 and the thirteenth valve 62 are closed, and the liquid inlet pipe 6 stops injecting the cleaning liquid into the first tank body 11. The eleventh valve 911 is opened, and the first nitrogen pipe 91 fills the IPA bubbling tank 13 with nitrogen, so that the IPA solution in the IPA bubbling tank 13 forms nitrogen bubbles, and the IPA is evaporated into the drying tank body 1; one end of the second pipe 8 connected to the IPA bubbling tank 13 is flush with the liquid level of the IPA solution in the IPA bubbling tank 13 in a circulating flow state, so that the IPA solution can overflow naturally from the second pipe 8 into the storage tank 10;

[0085] S3. Slow drainage: After the first nitrogen pipe 91 continuously fills the IPA bubbling tank 13 with nitrogen for a set time, the first valve 421 and the electromagnetic pump 422 are opened, and the ninth valve 441 is closed. The first drain pipe 4 starts slow drainage. The cleaning liquid in the first tank 11 is discharged successively through the first section 41, the second section 42, and the third section 43. When the liquid level of the cleaning liquid drops to expose the wafers 31 by a set height (about 2 cm), the wafer chuck 15 rotates and abuts against the tops of the multiple wafers 31, and cooperates with the wafer support 16 to restrain the postures and positions of the multiple wafers 31, preventing the wafers 31 from shaking. The lifting mechanism 2 slowly descends to point D, and the multiple wafers 31 are separated from the wafer cassette 3, and the wafer cassette 3 is supported at the bottom of the wafer support 16. When the liquid level of the cleaning liquid continues to drop below the wafer cassette 3, the eleventh valve 911 is closed, the first nitrogen pipe 91 stops filling the IPA bubbling tank 13 with nitrogen, the first valve 421 and the electromagnetic pump 422 are closed, and the slow drainage of the first drain pipe 4 stops. The air bladder pump 73, the third valve 72, the fourth valve 74, and the second valve 81 are closed. The IPA stock solution barrel 102 and the storage tank 10 stop injecting the IPA solution into the IPA bubbling tank 13. The fifth valve 75 and the seventh valve 771 are opened, and the IPA solution in the IPA bubbling tank 13 flows back to the storage tank 10 through the second pipe 8. Among them, the wafer chuck 15 is also prior art. In some embodiments, the wafers 31 may not be constrained and fixed by the wafer chuck 15, but fixed by the wafer support 16 itself. In some embodiments, the round cassette 3 can be inclined and supported at the bottom of the wafer support 16, so that the round cassette 3 is not prone to accumulating cleaning liquid.

[0086] S4. Fast drainage: The first valve 421 is closed, and the ninth valve 441 is opened, so that the cleaning liquid quickly drains through the first section 41, the sixth pipe 44, and the third section 43. The lifting mechanism 2 rises to point C, and the wafer chuck 15 rotates back to its original position. After all the cleaning liquid in the first tank 11 is drained, after a set time, the ninth valve 441 is closed.

[0087] S5. Drying of the wafers 31: The tenth valve 921 is opened, and the supply pipe 9 and the second nitrogen pipe 92 supply nitrogen to the multiple nitrogen nozzles 141 on the tank cover 14. At the same time, the gas online heater 922 is turned on to heat the nitrogen, so that the hot nitrogen ejected from the multiple nitrogen nozzles 141 dries the wafers 31 and the wafer cassette 3. After drying for a set time, the tank cover 14 is opened, the lifting mechanism 2 rises to point A, the gas online heater 922 is turned off, and the supply pipe 9 and the second nitrogen pipe 92 continue to supply nitrogen to the multiple nitrogen nozzles 141 on the tank cover 14 in a small flow rate. All the IPA solution in the IPA bubbling tank 13 flows back to the storage tank 10.

[0088] S6. Process End: The tenth valve 921 is closed, the gas supply pipe 9 and the second nitrogen gas pipe 92 stop supplying nitrogen gas to the multiple nitrogen nozzles 141 of the tank cover 14, the tank cover 14 is closed, the lifting mechanism 2 rises to point B, the thirteenth valve 62 is opened, the liquid inlet pipe 6 slowly injects the cleaning liquid into the first tank body 11, the wafer cassette 3 on the lifting mechanism 2 is removed, after the liquid level of the cleaning liquid in the first tank body 11 reaches the specified position, the twelfth valve 63 is opened, and the cleaning liquid starts to be quickly injected into the first tank body 11 through the liquid inlet pipe 6. After the liquid level of the cleaning liquid in the first tank body 11 reaches the specified position, the twelfth valve 63 is closed, and the liquid inlet pipe 6 slowly injects the cleaning liquid into the first tank body 11 to make the cleaning liquid in the first tank body 11 in a full water slow overflow state;

[0089] The lifting height points of the lifting mechanism 2 from high to low are: point B, point A, point C, point D.

[0090] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written out should also be considered as within the scope described in this specification.

[0091] In the above text, the present application has been described in a relatively specific and detailed manner through general descriptions and specific embodiments. It should be understood that based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; but as long as they do not depart from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the protection scope of the claims of the present application.

Claims

1. A cleaning and drying structure assembly of a wafer dryer, the wafer dryer comprising a main body and a lifting mechanism connected to the main body and used to lift a wafer box, characterized in that: The cleaning and drying structure assembly includes a drying tank body connected to the main body, a liquid inlet pipe connected to the drying tank body and used to inject cleaning liquid into the drying tank body, an IPA bubbling box connected to the drying tank body and used to inject isopropyl alcohol vapor into the drying tank body, a first liquid discharge pipe connected to the drying tank body and used to discharge the cleaning liquid in the drying tank body, and a controller connected to the main body; The drying tank body is connected to its own notch with a tank cover for sealing its own notch; The first liquid discharge pipe is connected to an electromagnetic pump, a first valve and a flow meter for measuring the flow rate of the liquid in the first liquid discharge pipe, and the electromagnetic pump and the flow meter are both electrically connected to the controller, so that the controller controls the flow rate of the electromagnetic pump according to the signal feedback of the flow meter on the flow rate of the liquid in the first liquid discharge pipe; The drying tank body comprises a first tank body connected to the main body and a second tank body connected to the top outer wall of the first tank body, the second tank body and the outer wall of the first tank body form an overflow tank, so that the cleaning liquid overflowing from the first tank body flows into the overflow tank, and the bottom of the overflow tank is connected to a second drain pipe; The liquid inlet pipe is connected to the side wall of the first trough body, the first liquid discharge pipe is connected to the bottom wall of the first trough body, the IPA bubbling box is connected to the side wall of the second trough body, and the box opening of the IPA bubbling box is higher than the slot opening of the first trough body, the slot cover is connected to the slot opening of the second trough body, the first liquid discharge pipe includes a first section connected to the first trough body, a second section connected to an end of the first section away from the first trough body, and a third section connected to an end of the second section away from the first section and used to discharge the cleaning liquid in the first trough body to the outside of the main body, the electromagnetic pump, the first valve and the flowmeter are connected to the second section, the first liquid discharge pipe is connected to the sixth pipeline, one end of the sixth pipeline is connected to the intersection of the first section and the second section, and the other end is connected to the intersection of the second section and the third section, the sixth pipeline is connected to the ninth valve, the highest point of the second section is higher than the slot opening of the first trough body, and the inner diameter of the third section gradually increases from the end close to the second section to the tail end of the third section.

2. The cleaning and drying structure assembly according to claim 1, characterized in that: The side wall of the IPA bubbling box is connected with a first nitrogen pipe for filling nitrogen into the IPA bubbling box. The nitrogen is bubbled in the IPA bubbling box to evaporate the IPA solution into the drying tank body.

3. The cleaning and drying structure assembly according to claim 2, characterized in that: The main body is connected to a liquid storage tank for storing IPA solution, the liquid storage tank is connected to a first pipeline for supplying IPA solution to the IPA bubbling box, and the liquid storage tank is also connected to a second pipeline for discharging the IPA solution in the IPA bubbling box back into the liquid storage tank. The main body is connected to an IPA stock solution barrel on the outside, and a third pipeline is connected between the IPA stock solution barrel and the first pipeline to replenish the IPA solution to the liquid storage tank; The first pipe and the second pipe cooperate to maintain the liquid level in the IPA bubbling box at a set height.

4. The cleaning and drying structure assembly according to claim 3, characterized in that: The second pipeline is connected to the second valve, the first pipeline is sequentially connected to the third valve, the wind bag pump, the fourth valve and the fifth valve from the liquid storage tank to the IPA bubbling box, the third valve is located between the liquid storage tank and the third pipeline, the wind bag pump, the fourth valve and the fifth valve are located between the third pipeline and the IPA bubbling box, and the third pipeline is connected to the sixth valve; A fourth pipeline is connected between the first pipeline and the liquid storage tank, the fourth pipeline is connected to a seventh valve, the first pipeline is connected to a filter, a fifth pipeline is connected between the filter and the liquid storage tank, and the fifth pipeline is connected to an eighth valve.

5. The cleaning and drying structure assembly according to claim 2, characterized in that: A gas supply pipe for providing nitrogen is connected to one end of the first nitrogen pipe away from the IPA bubbling box, a second nitrogen pipe is connected between the gas supply pipe and the tank cover, the tank cover is connected to a plurality of nitrogen nozzles connected to the second nitrogen pipe, the second nitrogen pipe is connected to a tenth valve and a gas online heater, and the first nitrogen pipe is connected to an eleventh valve.

6. The cleaning and drying structure assembly according to claim 1, characterized in that: The liquid inlet pipe is connected to a twelfth valve, the liquid inlet pipe is connected to a seventh pipeline, the seventh pipeline is connected to a thirteenth valve in parallel with the twelfth valve, and the diameter of the thirteenth valve is smaller than the diameter of the twelfth valve.

7. A wafer drying machine, characterized in that: A cleaning and drying structure assembly comprising a wafer dryer according to any one of claims 1-6.

8. A wafer cleaning and drying process implemented by the wafer drying machine according to claim 7, characterized in that: The following steps are involved: S1, standby state before wafer cleaning: the thirteenth valve is opened, the twelfth valve is closed, the liquid inlet pipe slowly injects cleaning liquid into the first tank body, the cleaning liquid in the first tank body is in a full and slow overflow state, the overflowing cleaning liquid enters the overflow tank, and is discharged through the second liquid discharge pipe and the third section, the lifting height of the lifting mechanism is at point A, the tank cover is in a closed state, the tenth valve on the second nitrogen pipe is opened, and multiple nitrogen nozzles on the tank cover blow nitrogen into the drying tank body; S2, wafer cleaning: the tenth valve on the second nitrogen pipe is closed, the multiple nitrogen nozzles on the tank cover stop blowing nitrogen into the drying tank body, the tank cover is opened, the lifting mechanism is lifted to point B, the wafer box is placed on the lifting mechanism, the lifting mechanism is lowered to point C, the multiple wafers in the wafer box are immersed in the cleaning liquid in the first tank body, and are held up by the wafer holder in the drying tank body, and the tank cover is closed; the twelfth valve on the liquid inlet pipe is opened, the liquid inlet pipe quickly injects cleaning liquid into the first tank body, the cleaning liquid in the first tank body is full and about to overflow, and the fifth valve is opened The twelfth and thirteenth valves are closed, the liquid inlet pipe stops injecting cleaning liquid into the first tank body, the eleventh valve is opened, and the first nitrogen pipe fills nitrogen into the IPA bubbling box, so that the IPA solution in the IPA bubbling box forms nitrogen bubbles, and the IPA is evaporated into the drying tank body; S3, slow drainage: After the first nitrogen pipe continuously fills the IPA bubbling box with nitrogen for a set time, the first valve and the electromagnetic pump are opened, the ninth valve is closed, and the first drain pipe starts to drain slowly. The cleaning liquid in the first tank is discharged through the first section, the second section and the third section in sequence. When the liquid level of the cleaning liquid drops to the set height of the exposed wafer, the wafer chuck rotates to abut against the top of the multiple wafers, and cooperates with the wafer holder to constrain the posture and position of the multiple wafers. The lifting mechanism slowly descends to point D, and the multiple wafers are separated from the wafer box, and the wafers are The box is supported at the bottom of the wafer support. When the liquid level of the cleaning solution continues to drop below the wafer box, the eleventh valve is closed, the first nitrogen pipe stops filling nitrogen into the IPA bubbling box, the first valve and the electromagnetic pump are closed, the slow drainage of the first drain pipe stops, the air bag pump, the third valve, the fourth valve and the second valve are closed, the IPA stock solution barrel and the liquid storage tank stop injecting IPA solution into the IPA bubbling box, the fifth valve and the seventh valve are opened, and the IPA solution in the IPA bubbling box flows back to the liquid storage tank through the second pipeline; S4, fast drainage: the first valve is closed, the ninth valve is opened, and the cleaning liquid is quickly discharged through the first section, the sixth pipe and the third section. The lifting mechanism rises to point C, the wafer chuck rotates back to its original position, and after all the cleaning liquid in the first tank is discharged, the ninth valve is closed after the set time has passed; S5, wafer drying: the tenth valve is opened, the gas supply pipe and the second nitrogen pipe supply nitrogen to the multiple nitrogen nozzles of the slot cover, and the gas online heater is turned on at the same time to heat the nitrogen, so that the hot nitrogen sprayed from the multiple nitrogen nozzles dries the wafers and the wafer box. After the set drying time, the slot cover is opened, the lifting mechanism rises to point A, the gas online heater is turned off, the gas supply pipe and the second nitrogen pipe continue to supply nitrogen to the multiple nitrogen nozzles of the slot cover at a small flow rate, and the IPA solution in the IPA bubbling box is all refluxed to the liquid storage tank; S6, process end: the tenth valve is closed, the gas supply pipe and the second nitrogen pipe stop supplying nitrogen to the multiple nitrogen nozzles of the tank cover, the tank cover is closed, the lifting mechanism rises to point B, the thirteenth valve is opened, the liquid inlet pipe slowly injects cleaning liquid into the first tank body, the wafer box on the lifting mechanism is removed, and after the liquid level of the cleaning liquid in the first tank body reaches the specified position, the twelfth valve is opened, and the cleaning liquid begins to be quickly injected into the first tank body through the liquid inlet pipe. After the liquid level of the cleaning liquid in the first tank body reaches the specified position, the twelfth valve is closed, and the liquid inlet pipe slowly injects cleaning liquid into the first tank body, so that the cleaning liquid in the first tank body is in a full water and slowly overflowing state; The lifting height points of the lifting mechanism are from high to low: point B, point A, point C, and point D.

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