Drying machine adopting supercritical medium and drying method

Abstract

The embodiment of the invention relates to the field of semiconductors, and provides a drying machine adopting a supercritical medium and a drying method. The base station is positioned in the cavity, and the base station is used for bearing a wafer; a first storage tank and a second storage tank; the second pipeline comprises a regulating valve, the regulating valve is located outside the box body and is communicated with the cavity through a pipeline body of the second pipeline, and the regulating valve is used for injecting the supercritical fluid into the cavity at a first flow rate and continuously injecting the supercritical fluid into the cavity at a second flow rate and a third flow rate; wherein the regulating valve comprises a first valve and a second valve which are connected in parallel, the first valve is used for injecting the supercritical fluid into the cavity at a first flow rate, the second valve is used for continuously injecting the supercritical fluid into the cavity at a second flow rate, and the first pipe diameter of the first valve is smaller than the second pipe diameter of the second valve.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of semiconductors, and in particular, to a dryer and a drying method using a supercritical medium. Background Art

[0002] With the continuous advancement of wafer manufacturing technology, the size of the patterned structures presented by the nano-scale microstructures in related chips is gradually decreasing. For example, 3D DRAM forms a stacked 3D DRAM memory structure by vertically stacking multiple layers of data storage units. This technology can support a higher storage capacity in a smaller space, thereby bringing significant cost savings, reduced energy consumption, and a substantial performance improvement, thus fully meeting the requirements of numerous consumer mobile devices and the most demanding enterprise deployments.

[0003] During the manufacturing process, any residual contamination will have an adverse impact on the quality of the wafer. Generally, various cleaning, etching, wet processes, etc. are used to clean the surface of the wafer. However, during the cleaning process, some water molecules and the like are often left on the surface of the wafer, and the aspect ratio of the internal transistors and storage structures is also set relatively large. During the removal of water molecules, the patterned structure on the surface of the wafer is easily damaged due to the tension problem. The occurrence of this problem greatly affects the cleaning efficiency and production quality of the wafer. Summary of the Invention

[0004] Embodiments of the present disclosure provide a dryer and a drying method using a supercritical medium, which are at least beneficial to improving the yield of wafers.

[0005] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a dryer using a supercritical medium, including: a box body having a chamber therein; a base located in the chamber for carrying wafers; a first storage tank and a second storage tank, the first storage tank for storing a cleaning liquid, and the second storage tank for storing a supercritical fluid; a first pipeline for connecting the first storage tank and the chamber; a second pipeline for connecting the second storage tank and the chamber; the second pipeline includes a regulating valve located outside the box body and communicating with the chamber through the pipeline of the second pipeline, and the regulating valve is used to inject the supercritical fluid into the chamber at a first flow rate, and continue to inject the supercritical fluid into the chamber at a second flow rate and a third flow rate; wherein, the regulating valve includes: a first valve and a second valve connected in parallel, the first valve is used to inject the supercritical fluid into the chamber at a first flow rate, and the second valve is used to continue to inject the supercritical fluid into the chamber at a second flow rate and a second flow rate, and a first pipe diameter of the first valve is smaller than a second pipe diameter of the second valve.

[0006] In some embodiments, the box body further includes: an air inlet located at the bottom of the chamber close to the base for outputting the supercritical fluid; an adjusting structure surrounding the base, and a top of the adjusting structure is higher than a top of the base; the adjusting structure is used for the supercritical fluid to be injected onto the wafer surface via a side surface of the adjusting structure away from the base and a top surface of the adjusting structure.

[0007] In some embodiments, the adjusting structure includes: a continuous body portion and an extending portion, the body portion surrounds the base, and the extending portion extends from an end of the body portion towards the base.

[0008] In some embodiments, the box body further includes: a valve for removing part of the gas medium converted from the supercritical fluid.

[0009] In some embodiments, the supercritical fluid is supercritical carbon dioxide fluid.

[0010] According to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure further provides a method for drying a wafer using a dryer employing a supercritical medium as described in the above embodiments, including: placing the wafer in a chamber; injecting a cleaning liquid into the chamber, the cleaning liquid covering the surface of the wafer, and the cleaning liquid being used to clean impurities on the surface of the wafer; a drying stage, the drying stage including consecutive first, second, and third stages, the first stage including: injecting a supercritical fluid into the chamber at a first flow rate using a first valve to control a first pressure increase rate at which the supercritical fluid is converted into a gas medium; the second stage including: continuing to inject the supercritical fluid into the chamber at a second flow rate using a second valve and causing the pressure increase rate at which the supercritical fluid is converted into a gas medium to be at a second pressure increase rate until the critical pressure at which the supercritical fluid is converted into the gas medium is reached; the third stage, injecting the supercritical fluid into the chamber at a third flow rate using the second valve, and the third stage causing the gas medium to carry away the cleaning liquid; wherein, the first pressure increase rate is less than the second pressure increase rate.

[0011] In some embodiments, the time of the first stage is 2 s to 20 s.

[0012] In some embodiments, the range of the first pressure increase rate is 0.01 MPa / s to 0.15 MPa / s.

[0013] In some embodiments, the first stage includes a first sub-stage and a second sub-stage, and the first sub-pressure increase rate of the first sub-stage is different from the second sub-pressure increase rate; the average value of the first sub-pressure increase rate and the second sub-pressure increase rate is between 0.01 MPa / s and 0.15 MPa / s.

[0014] In some embodiments, the first flow rate is equal to the second flow rate, and the first stage further includes: opening a valve in the chamber and removing part of the gas medium through the valve so that the pressure increase rate of the gas medium is at the first pressure increase rate.

[0015] The technical solution provided by the embodiment of the present disclosure has at least the following advantages:

[0016] The dryer using a supercritical medium provided by the embodiments of the present disclosure sets a first pipeline and a second pipeline. The first pipeline is used to transport a cleaning liquid, and based on the high solubility and fluidity of the cleaning liquid, the impurities are cleaned, thereby ensuring that the impurities on the surface of the wafer can be completely removed. The second pipeline is used to transport a supercritical fluid. Based on the property of the supercritical fluid being adjacent to the liquid in the critical state, that is, having a small viscosity and a high diffusion coefficient, it has a high dissolving ability and penetration ability, and can dissolve the cleaning liquid and the impurities, and then the impurities can be carried out. The embodiments of the present disclosure can remove the impurities on the surface of the wafer through two dissolution cleaning methods and drying methods, thereby improving the yield of the wafer. In addition, the second pipeline is provided with a regulating valve, that is, a first valve and a second valve connected in parallel. By regulating the first valve and the second valve, different pressure increasing rates are obtained in different stages, and then the state of the supercritical fluid in the chamber is regulated, that is, the gas path of the supercritical fluid is changed, so that the path of the supercritical fluid does not completely pass through the edge of the wafer or coincides with the edge to a small extent, so as to reduce the rapid volatilization of the cleaning liquid at the edge. Secondly, controlling the pressure increasing rate can also control the viscosity and density to reduce the volatilization of the cleaning liquid at the edge and improve the problem of collapse at the edge of the top pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a proportional limitation. To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following-described drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic structural diagram of a dryer;

[0019] Figure 2 It is a schematic structural diagram of a dryer provided by an embodiment of the present disclosure;

[0020] Figure 3 It is a schematic structural diagram of a chamber of a dryer provided by an embodiment of the present disclosure

[0021] Figure 4 It is a time-pressure diagram of a pipeline for introducing supercritical carbon dioxide in a drying method provided by an embodiment of the present disclosure;

[0022] Figure 5 It is Figure 4 A partial view of point A in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] As is known from the background art, the current yield of wafers is not good.

[0024] Currently, the methods mainly used to remove impurities or water molecules on the wafer surface are: 1. Spin Dry method using mechanical centrifugal force; 2. IPA Dry method using isopropyl alcohol. Spin Dry method using mechanical centrifugal force: Its principle is to utilize the centrifugal force generated by high-speed rotation and cooperate with the clean air flow sprayed by the air filter to spin dry the water droplets on the chip. According to Bernoulli's principle, the water droplets in the deep trench will also be sucked out, evaporated and dried without particles and water marks. IPA Dry method: Transfer the wet chip to an isopropyl alcohol (IPA) overflow deionized water (DIW) tank. Isopropyl alcohol (IPA) uses N2 as the transfer gas. N2 is introduced into the heated IPA liquid to generate gaseous IPA, which is introduced into the tank. Combining the action of slowly pulling the wafer out of the overflow DIW tank will make the IPA concentration on the wafer surface higher than that of the liquid surface. In this way, due to the IPA concentration difference, the water droplets flow into the tank, and at the same time, the high volatility of IPA can dehydrate and dry the water on the wafer surface.

[0025] However, for wafers with deep and narrow trenches, the drying effect of the Spin Dry method is not ideal, and due to the high-speed rotation in the process, it will affect the mechanical strength of the wafer. The IPA Dry method requires a large amount of liquid IPA to wash the surface, resulting in a high cost.

[0026] Therefore, the supercritical fluid drying method is combined for wafer drying. The supercritical fluid drying technology is a technology that completes the drying of materials when the drying medium is in a critical temperature and critical pressure state. First, the drying medium enters the interior of the material to be dried in a supercritical state and gently and quickly exchanges with the solvent molecules to replace the solvent; then, by changing the operating parameters (temperature, pressure), the fluid is changed from a supercritical state to a gas and released from the dried raw material to achieve the drying effect.

[0027] Figure 1 It is a schematic structural diagram of a dryer. Figure 1 For the arrows in, except for the two arrows located above the wafer representing the volatilization direction of the cleaning liquid, the remaining arrow directions represent the gas flow direction of the supercritical medium.

[0028] Combined with reference Figure 1 , there is a chuck 110 in the cavity 100. A wafer 10 is placed on the surface of the chuck 110. The surface of the wafer 10 has a cleaning liquid L. The cleaning liquid L forms a mixture with the impurities (such as water or contaminants) on the wafer surface. Driven by the supercritical medium, the cleaning liquid L and the impurities are carried out, so as to achieve the purpose of drying.

[0029] Then, the current existing supply pipeline will cause the cleaning liquid L at the edge of the wafer to volatilize too quickly, resulting in serious collapse of the pattern at the edge of the wafer due to excessive surface tension, which affects the product yield.

[0030] The embodiment of the present disclosure provides a semiconductor structure. A regulating valve is formed by a first valve and a second valve connected in parallel. By different regulating valve states, supercritical fluid is injected into the chamber at different flow rates, so as to change the air flow direction of the supercritical fluid, thereby avoiding excessive erosion of the edge of the wafer by the supercritical fluid, improving the problem of excessive volatilization of the cleaning liquid at the edge, and improving the yield of the wafer.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the embodiments of the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present disclosure. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0033] In the description of the embodiments of the present disclosure, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present disclosure and simplifying the description. Without contrary explanation, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the protection scope of the embodiments of the present disclosure; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0034] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figure for the device. For example, if the device in the figure is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations will be made for the spatial relative descriptions used here.

[0035] In addition, it should be noted that the use of terms such as "first", "second" etc. to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the scope of protection of the present disclosure.

[0036] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are provided to help readers better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed by the present disclosure can still be implemented.

[0037] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a dryer using a supercritical medium for improving the yield of the wafer 10. Refer to Figure 1 and Figure 2, the dryer includes: a box body 20 with a chamber 200 therein; a base 210 located within the chamber 200 for carrying the wafer 10. The dryer includes: a first storage tank 231 for storing a cleaning liquid L, and a second storage tank 232 for storing a supercritical fluid; a first pipeline for connecting the first storage tank 231 to the chamber 200; a second pipeline for connecting the second storage tank 232 to the chamber 200; the second pipeline includes a regulating valve located outside the box body 20 and communicating with the chamber 200 through the pipeline of the second pipeline, and the regulating valve is used to inject the supercritical fluid into the chamber 200 at a first flow rate, and continue to inject the supercritical fluid into the chamber 200 at a second flow rate and a third flow rate; wherein, the regulating valve includes: a first valve 251 and a second valve 252 connected in parallel, the first valve 251 is used to inject the supercritical fluid into the chamber 200 at the first flow rate, the second valve 252 is used to continue to inject the supercritical fluid into the chamber 200 at the second flow rate and the second flow rate, and the first diameter of the first valve 251 is smaller than the second diameter of the second valve 252.

[0038] The dryer using a supercritical medium provided by the embodiments of the present disclosure, by providing a first pipeline and a second pipeline, uses the first pipeline to transport the cleaning liquid L, and based on the high solubility and fluidity of the cleaning liquid L to achieve the cleaning of impurities, thereby ensuring that the impurities on the surface of the wafer 10 can be completely removed; uses the second pipeline to transport the supercritical fluid, based on the property of the supercritical fluid being adjacent to the liquid in the critical state, that is, having a small viscosity and a high diffusion coefficient, to have a high dissolution ability and penetration ability, and can dissolve the cleaning liquid L and the impurities, and then can bring out the impurities. The embodiments of the present disclosure can remove the impurities on the surface of the wafer 10 through two dissolution cleaning methods and drying methods, thereby improving the yield of the wafer 10. In addition, a regulating valve is provided in the second pipeline, that is, a first valve 251 and a second valve 252 connected in parallel are included. By regulating the first valve 251 and the second valve 252, different pressure boosting rates are obtained in different stages, and then the state of the supercritical fluid in the chamber 200 is regulated, that is, the gas path of the supercritical fluid is changed, so that the path of the supercritical fluid does not completely pass through the edge of the wafer 10 or coincides with the edge to a small extent, to reduce the rapid volatilization of the cleaning liquid at the edge. Secondly, controlling the pressure boosting rate can also control the viscosity and density to reduce the volatilization of the cleaning liquid at the edge and improve the problem of collapse at the edge of the top pattern.

[0039] As the temperature and pressure in the environment change, some substances exist in three phases, namely gas phase, liquid phase and solid phase. The state point where the three phases coexist in equilibrium is called the triple point, and the state point where the liquid-gas two-phase interface disappears is called the critical point. The temperature and pressure at the critical point are called the critical temperature and critical pressure, and the critical pressures and temperatures of different substances are different.

[0040] Supercritical medium, also called supercritical fluid (abbreviated as SCF), refers to a fluid whose temperature and pressure are both higher than its critical point. When an object is in the supercritical state, since the properties of the gas and liquid phases are very similar and it is impossible to clearly distinguish them, it is called a supercritical fluid. Its properties have mutability and adjustability, that is, near the critical point, small changes in pressure and temperature will significantly affect the volumetric properties of the supercritical fluid, such as density, solubility parameter, etc. Therefore, the equilibrium properties (phase equilibrium and solubility) and mass transfer properties (heat transfer coefficient, mass transfer coefficient) of the system can be controlled by controlling the temperature and pressure of the system, so as to achieve the purpose of drying the object to be dried.

[0041] The drying process of supercritical fluid utilizes the relationship between the solubility of supercritical fluid and its density, that is, it utilizes the influence of pressure and temperature on the solubility of supercritical fluid. When a substance is in the supercritical state, it becomes a single phase with properties between liquid and gas, having a density similar to that of a liquid, a viscosity higher than that of a gas but significantly lower than that of a liquid, and a diffusion coefficient 10 - 100 times that of a liquid. Therefore, it has good permeability and strong solubility to the material, and can extract certain components from the material.

[0042] In some embodiments, the cleaning liquid L can be isopropyl alcohol, which has good solubility and volatility. It can quickly dissolve oils, dirt and other organic substances and carry these substances away by evaporation without leaving any residue.

[0043] In some embodiments, the cleaning liquid L can be acetone or other alcohol solvents, and other alcohols refer to alcohol solutions with high solubility and high volatility.

[0044] In some embodiments, the supercritical fluid can be supercritical carbon dioxide fluid, supercritical ammonia fluid, supercritical ethylene fluid, supercritical propane fluid, supercritical propylene fluid, supercritical water fluid, etc.

[0045] In some embodiments, the supercritical fluid is supercritical carbon dioxide fluid. When carbon dioxide is in a state where the temperature is higher than the critical temperature Tc = 31.26 °C and the pressure is higher than the critical pressure Pc = 72.9 atm, its properties will change. Its density is close to that of a liquid, its viscosity is close to that of a gas, its diffusion coefficient is 100 times that of a liquid, it has a high solubility, and it has the advantages of easy attainment of critical conditions, high drying efficiency, stable chemical properties, colorless, odorless, non-toxic, pollution-free, low price, high purity, and easy availability. During drying, by utilizing the unique properties of carbon dioxide in the supercritical state, residues such as moisture on the wafer 10 are dissolved, avoiding pattern deformation on the surface of the wafer 10 caused by capillary forces generated during the evaporation of moisture, thereby achieving the purpose of maximizing the protection of the structure of the wafer 10 while drying the wafer 10, and still maintaining the excellent physical and chemical properties of the wafer 10 after drying.

[0046] In some embodiments, the first storage tank 231 and the second storage tank 232 are two independent storage tanks to ensure the purity of the cleaning liquid L and the purity of the supercritical fluid.

[0047] In other embodiments, the first storage tank and the second storage tank are the same storage tank. After entering from the same liquid inlet, they are stored in the same storage tank. When changing to another reactant, the storage tank can be cleaned to avoid contamination between reactants. In this way, the first pipeline can be discarded, and the second pipeline can be retained as the main pipeline. The cleaning liquid is introduced into the chamber through the first valve, simplifying the structure of the dryer.

[0048] In some embodiments, either the first valve 251 or the second valve 252 can be a ball valve, a diaphragm valve, or a bellows valve.

[0049] In some embodiments, the first valve 251 and the second valve 252 can be electric control valves or manual control valves, and the control module controls the opening and closing of the first valve 251 and the second valve 252.

[0050] The first pipe diameter of the first valve 251 is smaller than the second pipe diameter of the second valve 252. Thus, on the premise that the flow rate at the inlet remains unchanged, if the first pipe diameter of the first valve 251 is smaller than the second pipe diameter of the second valve 252, the outlet flow rate of the supercritical fluid corresponding to the first valve 251 will correspondingly decrease, and then the pressure will also decrease appropriately, thereby slowing down the flow rate of the supercritical fluid entering the chamber 200. As a result, the path of the supercritical fluid coming out from the gas outlet also changes accordingly, reducing the erosion of the edge of the wafer 10, and the supercritical fluid in this state also has a smaller solubility, and the cleanliness of the cleaning liquid L at the edge of the wafer 10 is also smaller, thereby reducing the volatilization of the cleaning liquid L at the edge.

[0051] It should be noted that the embodiments of the present application do not limit the sizes of the first pipe diameter and the second pipe diameter, and those skilled in the art can design the sizes of the first pipe diameter and the second pipe diameter according to actual needs.

[0052] Continuing to refer to Figure 2 , the first pipeline includes a third valve 241 and a first heating device 242. The first heating device 242 is used for heating the cleaning liquid L and turning it into a cleaning gas. The first pipeline includes a first pressure sensor 243 and a first temperature sensor 244. The first pressure sensor 243 and the first temperature sensor 244 are respectively used to obtain the pressure and temperature of the first pipeline.

[0053] Continuing to refer to Figure 2 , the second pipeline includes a second heating device 255. The second heating device 255 is used for heating the supercritical fluid and turning it from a liquid into a supercritical fluid. The second pipeline includes a second pressure sensor 253 and a second temperature sensor 254. The second pressure sensor 253 and the second temperature sensor 254 are respectively used to obtain the pressure and temperature of the second pipeline.

[0054] In some embodiments, the box body 20 further includes: an air inlet 201, the air inlet 201 is located at the bottom of the chamber 200 close to the base 210, and the air inlet 201 is used for outputting the supercritical fluid; an adjusting structure 220, the adjusting structure 220 surrounds the base 210, and the top of the adjusting structure 220 is higher than the top of the base 210; the adjusting structure 220 is used for injecting the supercritical fluid onto the surface of the wafer 10 through the side surface of the adjusting structure 220 away from the base 210 and the top surface of the adjusting structure 220. By changing the path of the supercritical fluid through the adjusting structure 220, the air outlet and the air outlet path of the supercritical fluid do not pass through the edge of the wafer 10, so as to improve the problem of excessive volatilization of the cleaning liquid at the edge of the wafer 10, thereby improving the yield of the wafer 10.

[0055] In some embodiments, the adjusting structure 220 includes: a continuous body portion 221 and an extending portion 222. The body portion 221 surrounds the base 210, and the extending portion 222 extends from the end of the body portion 221 towards the base 210. In this way, the extending portion 222 serves as a guiding structure, which can not only block the excessive scouring of the edge of the wafer 10 by the supercritical fluid, but also guide the supercritical fluid above the wafer 10, so as to clean the wafer 10 at a uniform flow rate and dry the moisture and cleaning liquid L remaining on the surface of the wafer 10.

[0056] In some embodiments, the included angle formed between the extension part 222 and the main body part 221 is an obtuse angle, and the size of the obtuse angle is between 100° and 170°. This range of the obtuse angle can change the path of the supercritical fluid while avoiding excessive erosion of the adjustment structure 220 by the supercritical fluid, thereby causing damage to the adjustment structure 220 and waste of the supercritical gas.

[0057] In some embodiments, the adjustment structure 220 can be fixed to the outer side surface of the base 210 to move along with the movement of the base 210.

[0058] In some embodiments, the main body part 221 of the adjustment structure 220 can be an annular structure with a telescopic structure. The telescopic structure drives the extension part 222 to move up and down, so as to appropriately adjust the height of the adjustment structure 220 according to the thickness of the wafer 10, ensuring that while changing the path of the supercritical fluid, it will not excessively block the wafer 10, causing waste of the supercritical fluid, and thus increasing the production cost.

[0059] It should be noted that the air inlet 201 is arranged at the bottom of the chamber 200 considering the density of the supercritical fluid, so that the supercritical fluid can be completely injected onto the surface of the wafer 10. Based on the volatility of the gas, the air outlet is arranged on the side surface and the top surface except the bottom, which is more conducive to the discharge of the mixed gas of the gas medium and the cleaning liquid L.

[0060] In some embodiments, the box body 20 further includes: a valve (not shown), and the valve is used to remove part of the gas medium converted from the supercritical fluid. The valve is the air outlet or the air extraction port.

[0061] The dryer using a supercritical medium provided by an embodiment of the present disclosure is provided with a first pipeline and a second pipeline. The first pipeline is used to transport a cleaning liquid L. Based on the high solubility and fluidity of the cleaning liquid L, the impurities can be cleaned, thereby ensuring that the impurities on the surface of the wafer 10 can be completely removed. The second pipeline is used to transport a supercritical fluid. Based on the property of the supercritical fluid being adjacent to a liquid in the critical state, that is, having a small viscosity and a high diffusion coefficient, it has a high dissolving ability and penetration ability, and can dissolve the cleaning liquid L and the impurities, and then the impurities can be carried out. The embodiment of the present disclosure can remove the impurities on the surface of the wafer 10 through two dissolution cleaning methods and drying methods, thereby improving the yield of the wafer 10. In addition, the second pipeline is provided with a regulating valve, that is, a first valve 251 and a second valve 252 connected in parallel are included. By regulating the first valve 251 and the second valve 252, different pressure increasing rates can be obtained in different stages, and then the state of the supercritical fluid in the chamber 200 can be regulated, that is, the gas path of the supercritical fluid is changed, so that the path of the supercritical fluid does not completely pass through the edge of the wafer 10 or coincides with the edge to a small extent, so as to reduce the rapid volatilization of the cleaning liquid at the edge. Secondly, controlling the pressure increasing rate can also control the viscosity and density to reduce the volatilization of the cleaning liquid at the edge and improve the problem of collapse at the edge of the top pattern.

[0062] Correspondingly, according to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure also provides a drying method for a wafer using the dryer with a supercritical medium as described in the above embodiments. The same or corresponding technical features as those in the above embodiments will not be described in detail here.

[0063] The drying method includes: placing the wafer in a chamber; injecting a cleaning liquid into the chamber, and the cleaning liquid covers the surface of the wafer, and the cleaning liquid is used to clean the impurities on the surface of the wafer. The drying method includes a drying stage, and the drying stage includes consecutive first, second, and third stages. The first stage includes: injecting a supercritical fluid into the chamber at a first flow rate using a first valve to control the first pressure increasing rate at which the supercritical fluid is converted into a gas medium; the second stage includes: continuing to inject the supercritical fluid into the chamber at a second flow rate using a second valve, and making the pressure increasing rate at which the supercritical fluid is converted into a gas medium be at a second pressure increasing rate until the critical pressure at which the supercritical fluid is converted into a gas medium is reached; the third stage is to inject the supercritical fluid into the chamber at a third flow rate using the second valve, and in the third stage, the gas medium takes away the cleaning liquid; wherein, the first pressure increasing rate is less than the second pressure increasing rate.

[0064] Figure 4 It is a time-pressure diagram of a pipeline for introducing supercritical carbon dioxide in a drying method provided by an embodiment of the present disclosure; Figure 5 is Figure 4 The partial view at point A in

[0065] It should be noted that Figure 4 and Figure 5 include the time - pressure diagram of the pipeline for introducing supercritical carbon dioxide in the original process; set the time - pressure curve of the pipeline for introducing supercritical carbon dioxide in the original process as the original process; set the time - pressure curve of the pipeline for introducing supercritical carbon dioxide in the embodiments of the present disclosure as the embodiments of the present disclosure. Among them, the curve of the third stage is not shown, and the curve of the third stage is that after the end of the second stage, supercritical pressure of 16.1 MPa is continuously introduced.

[0066] Referring to Figure 4 and Figure 5 , the first stage, the second stage and the third stage are set. The ratio of pressure to time within the first stage, that is, the pressure - rising rate, is relatively small, so that the state of the supercritical fluid is gas and the air pressure is low, changing the gas path of the supercritical fluid, so that the path of the supercritical fluid does not completely pass through the edge of the wafer or coincides with the edge to a small extent, in order to reduce the rapid volatilization of the cleaning liquid at the edge.

[0067] In some embodiments, the time of the first stage is 2 s to 20 s. The time of the first stage can be 2 s, 4 s, 6 s, 8 s, 10 s, 11 s, 13 s, 15 s, 17 s, 19 s or 20 s.

[0068] It should be noted that the start time of the first stage is not equal to the start time of the reaction, that is, the start of the first stage is the time of introducing the supercritical fluid, and the reaction time can be earlier than the start time of the first stage.

[0069] In some embodiments, the first pressure - rising rate range is 0.01 MPa / s to 0.15 MPa / s. The first pressure - rising rate range is 0.01 MPa / s, 0.03 MPa / s, 0.08 MPa / s, 0.11 MPa / s, 0.13 MPa / s or 0.15 MPa / s.

[0070] In some embodiments, the first stage includes a first sub - stage and a second sub - stage, and the first sub - pressure - rising rate of the first sub - stage is different from the second sub - pressure - rising rate; the average value of the first sub - pressure - rising rate and the second sub - pressure - rising rate is between 0.01 MPa / s and 0.15 MPa / s.

[0071] In some embodiments, the first flow rate is equal to the second flow rate. The first stage further includes: opening the valve in the chamber and removing part of the gas medium through the valve, so that the pressure - rising rate of the gas medium is at the first pressure - rising rate.

[0072] In some embodiments, the first stage further includes: turning on the heater and heating the chamber at a first heating rate to change the critical state of the supercritical fluid in the chamber.

[0073] The drying method provided by the embodiments of the present disclosure: By setting that the drying stage includes a first stage, a second stage, and a third stage, controlling and adjusting the flow rate of the control gas in the first stage, controlling the pressure increase rate of the supercritical fluid in the chamber, and further regulating the state of the supercritical fluid in the chamber, that is, changing the gas path of the supercritical fluid, so that the path of the supercritical fluid does not completely pass through the edge of the wafer, in order to reduce the rapid volatilization of the cleaning liquid at the edge. Secondly, controlling the pressure increase rate can also control the viscosity and density (small) to reduce the volatilization of isopropyl alcohol at the edge and improve the problem of collapse at the edge of the top pattern. In the second stage and the third stage, it is used to make the supercritical fluid have a higher solubility, so as to drive the cleaning liquid and impurities out as soon as possible.

[0074] Correspondingly, according to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a terminal device, including a processor and a storage device, and the storage device is used to store one or more programs; when the one or more programs are executed by the processor, the processor implements the above-mentioned drying method.

[0075] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The so-called processor is the control center of the test device, and uses various interfaces and lines to connect all parts of the entire test device.

[0076] The storage device can be used to store computer programs and / or modules. The processor can realize various functions of the terminal device by running or executing the computer programs and / or modules stored in the storage device, and by calling the data stored in the storage device. The storage device mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function, etc.; the data storage area can store data created according to the use of the terminal device, etc. In addition, the storage device can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0077] Among them, if the modules / units integrated in the detection system of the lithography machine are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present disclosure, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in at least one computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0078] It should be noted that the above-described embodiments of the devices and apparatuses are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present disclosure.

[0079] Those of ordinary skill in the art can understand that the above-described embodiments are specific examples for implementing the present disclosure. In actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A dryer using a supercritical medium, characterized in that, Comprising: A box body, which has a chamber inside; A base platform, which is located inside the chamber and is used for carrying wafers; A first storage tank and a second storage tank, where the first storage tank is used for storing cleaning liquid and the second storage tank is used for storing supercritical fluid; A first pipeline, which is used to connect the first storage tank and the chamber; A second pipeline, which is used to connect the second storage tank and the chamber; the second pipeline includes a regulating valve, the regulating valve is located outside the box body and is in communication with the chamber through the pipeline of the second pipeline, and the regulating valve is used to inject supercritical fluid into the chamber at a first flow rate, and continue to inject the supercritical fluid into the chamber at a second flow rate and a third flow rate; wherein, the regulating valve includes: A first valve and a second valve connected in parallel, the first valve is used to inject supercritical fluid into the chamber at a first flow rate, the second valve is used to continue to inject the supercritical fluid into the chamber at a second flow rate and a second flow rate, and the first pipe diameter of the first valve is smaller than the second pipe diameter of the second valve.

2. The dryer using a supercritical medium according to claim 1, characterized in that, The box body further includes: An air inlet, which is located at the bottom of the chamber close to the base platform and is used to output the supercritical fluid; An adjusting structure, which surrounds the base platform, and the top of the adjusting structure is higher than the top of the base platform; the adjusting structure is used for the supercritical fluid to be injected onto the surface of the wafer through the side surface of the adjusting structure away from the base platform and the top surface of the adjusting structure.

3. The dryer using a supercritical medium according to claim 2, characterized in that, The adjusting structure includes: a continuous body part and an extension part, the body part surrounds the base platform, and the extension part extends from the end of the body part towards the base platform.

4. The dryer using a supercritical medium according to claim 1, characterized in that, The box body further includes: a valve, which is used to remove part of the gas medium converted from the supercritical fluid.

5. The dryer using a supercritical medium according to claim 1, characterized in that, The supercritical fluid is supercritical carbon dioxide fluid.

6. A drying method for wafers using the dryer with supercritical medium according to any one of claims 1 to 5, characterized in that, Comprising: Placing the wafer in the chamber; Injecting cleaning liquid into the chamber, the cleaning liquid covers the surface of the wafer, and the cleaning liquid is used to clean the impurities on the surface of the wafer; A drying stage, the drying stage includes continuous first, second, and third stages, the first stage includes: using the first valve to inject supercritical fluid into the chamber at a first flow rate to control the first pressure increase rate of the supercritical fluid converting into a gas medium; the second stage includes: using the second valve to continue to inject the supercritical fluid into the chamber at a second flow rate and making the pressure increase rate of the supercritical fluid converting into a gas medium be at a second pressure increase rate until reaching the critical pressure of the supercritical fluid converting into the gas medium; the third stage, using the second valve to inject supercritical fluid into the chamber at a third flow rate, and the third stage enables the gas medium to carry away the cleaning liquid; wherein, the first pressure increase rate is less than the second pressure increase rate.

7. The drying method according to claim 6, characterized in that The time of the first stage is 2s to 20s.

8. The drying method according to claim 7, characterized in that, The range of the first pressure increase rate is 0.01MPa / s to 0.15MPa / s.

9. The drying method according to claim 8, wherein The first stage includes a first sub-stage and a second sub-stage, and the first sub-boosting rate of the first sub-stage is different from the second sub-boosting rate; the average value of the first sub-boosting rate and the second sub-boosting rate is between 0.01 MPa / s and 0.15 MPa / s.

10. The drying method according to claim 6, characterized in that, The first flow rate is equal to the second flow rate. The first stage further includes: opening a valve in the chamber and removing a part of the gas medium through the valve so that the boosting rate of the gas medium is at a first boosting rate.

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