Substrate drying apparatus and substrate drying method

Abstract

The invention provides a substrate drying device and method. The device comprises a cavity, a fluid supply unit, a pressure reduction unit, a detection unit and a control unit, and the control unit is configured to control the detection unit to obtain detection data in real time after the pressure reduction unit is started, judge whether the detection data is lower than a preset threshold value or not, and control the pressure reduction unit to be opened if the detection data is lower than the preset threshold value. If yes, the pressure reduction unit is closed. The negative pressure pumping of the chamber is stopped only when the detection data is lower than the preset threshold value, compared with an automatic negative pressure pumping mode within the fixed time, the steam content of water vapor or IPA in the chamber is easier to control, the threshold value can be flexibly set according to the actual process condition, the requirements for the steam content of water vapor and IPA in different drying processes are met, and the drying efficiency is improved. And adhesion and collapse of the pattern structure on the surface of the substrate are effectively avoided. And the method is suitable for various drying processes and is wide in application range.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing equipment, and in particular to a substrate drying apparatus and a substrate drying method. Background Technology

[0002] Currently, ultra-low pressure drying technology is commonly used to dry substrates. During the drying process, high-temperature nitrogen gas and high-temperature IPA (isopropanol) vapor are supplied to the chamber. Subsequently, a substrate lifting mechanism slowly lifts the substrate from the pure water in the storage tank, using IPA to replace the moisture on the substrate surface. Then, the pressure inside the chamber is reduced, i.e., the IPA is evaporated under vacuum conditions, thereby achieving the drying of the substrate.

[0003] However, different drying processes have different requirements for the content of water vapor or IPA vapor. Especially with the future development trend of chips, feature sizes are becoming smaller and aspect ratios are increasing. Due to the surface tension of liquids, the substrate surface pattern structure can easily adhere and collapse during cleaning and drying. Therefore, future chip drying processes will have even higher requirements for the content of water vapor or IPA vapor. When creating negative pressure in the drying chamber, it is usually set in software to automatically create negative pressure for a fixed time. The longer the negative pressure is created, the more IPA evaporates, and the lower the IPA vapor content. However, this current method of creating negative pressure for a fixed time cannot control the content of water vapor or IPA vapor in the chamber, and therefore cannot meet the different requirements for water vapor or IPA vapor content in different drying processes. Summary of the Invention

[0004] The purpose of this application is to provide a substrate drying apparatus and a substrate drying method to solve the problem that the existing technology cannot meet the requirements of water vapor or IPA vapor content in different drying processes.

[0005] To achieve the above and other related objectives, this application provides a substrate drying apparatus, comprising:

[0006] A chamber for providing a sealed space for processing a substrate, the chamber including a liquid reservoir for containing processing liquid and the substrate;

[0007] A fluid supply unit for supplying solvent vapor into the chamber;

[0008] A pressure reduction unit is used to reduce the pressure in the chamber;

[0009] A detection unit is used to acquire detection data, which includes any one or more of the following: chamber pressure value, liquid vapor content value, and solvent vapor content value;

[0010] The control unit is configured to: after the decompression unit is turned on, control the detection unit to acquire the detection data in real time, determine whether the detection data is lower than a preset threshold, and if the detection data is lower than the preset threshold, turn off the decompression unit.

[0011] Preferably, the chamber further includes a drying position and a substrate lifting mechanism. The drying position is located above the liquid storage tank, and the substrate lifting mechanism supports the substrate and drives the substrate to move up and down between the liquid storage tank and the drying position.

[0012] Preferably, it further includes a fluid discharge unit for discharging the treatment liquid and vapor from the chamber; the fluid discharge unit includes an exhaust pipe and a drain pipe.

[0013] Preferably, the treatment solution is pure water.

[0014] Preferably, the solvent is IPA.

[0015] This application also proposes a substrate drying method, applied to the aforementioned substrate drying apparatus, including a depressurization drying step, wherein the depressurization drying step includes: after opening the depressurization unit to depressurize the chamber, acquiring the detection data of the detection unit in real time, determining whether the detection data is lower than a preset threshold, and if so, closing the depressurization unit; wherein the detection data includes any one or more of the following: chamber pressure value, processing liquid vapor content value, and solvent vapor content value.

[0016] Preferably, the pressure reduction drying process is followed by a pressure reduction process, which includes supplying purge gas into the chamber to reduce the internal pressure of the chamber to atmospheric pressure.

[0017] Preferably, the exhaust pipe is opened when the internal air pressure of the chamber reaches a positive pressure.

[0018] Preferably, a solvent replacement process on the substrate surface is included before the reduced pressure drying process. The solvent replacement process on the substrate surface includes: supplying solvent vapor into the chamber at a first flow rate and raising the substrate from the liquid storage tank in the chamber to the drying position by a substrate lifting mechanism; after the substrate reaches the drying position, supplying solvent vapor into the chamber at a second flow rate; wherein the second flow rate is greater than the first flow rate.

[0019] Preferably, the solvent replacement process on the substrate surface further includes: identifying the number of substrates in the chamber and adjusting the value of the second flow rate according to a preset correspondence between the number of substrates and the second flow rate.

[0020] As described above, this application provides a substrate drying apparatus and a substrate drying method, which have the following advantages: The negative pressure in the chamber is only stopped after the detected data falls below a preset threshold. Compared to the automatic negative pressure extraction method within a fixed time, it is easier to control the moisture or IPA vapor content in the chamber. The threshold can be flexibly set according to the actual process conditions to meet the requirements of moisture and IPA vapor content in different drying processes, effectively preventing the adhesion and collapse of the substrate surface pattern structure. Furthermore, it is applicable to a variety of drying processes and has a wide range of applications. Attached Figure Description

[0021] Figure 1 The diagram shown is a schematic diagram of a substrate drying apparatus in an embodiment of this application.

[0022] Figure 2 The flowchart shown is a substrate drying method in an embodiment of this application.

[0023] Figure 3 The flowchart shown is a process of vacuum drying in an embodiment of this application. Detailed Implementation

[0024] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0025] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Although the illustrations only show components relevant to this application and are not drawn according to the actual number, shape, and size of components in implementation, the shape, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the layout of the components may also be more complex. In addition, the same reference numerals in multiple figures represent the same or equivalent parts or components.

[0026] like Figure 1As shown, this application proposes a substrate drying apparatus, comprising: a chamber 1 for providing a sealed space for processing a substrate w; a substrate lifting mechanism 2 disposed within the chamber for holding the substrate w and driving the substrate w to rise and fall; a fluid supply unit 3 for supplying solvent vapor into the chamber 1; a fluid discharge unit 4 for discharging solvent vapor from the chamber 1; a pressure reduction unit 5 for reducing pressure within the chamber 1; a detection unit 6 for acquiring detection data in real time, the detection data being any one or more of the pressure value, water vapor content value, and solvent vapor content value within the chamber 1; and a control unit (not shown in the figure) for determining in real time whether the detection data is lower than a preset threshold after the pressure reduction unit 5 is turned on, and if so, turning off the pressure reduction unit 5.

[0027] The chamber 1 includes a storage tank 11 and a drying position 12, which is located above the storage tank 11. The storage tank 11 is used to hold the substrate w and the processing liquid. The processing liquid is typically pure water (i.e., deionized water). The storage tank 11 has side walls and a bottom wall, forming a semi-enclosed space with an open top. A processing liquid supply line L1 is located at the bottom of the storage tank 11 to supply the processing liquid into the storage tank 11. A quick-drainage line L2 for the processing liquid is also located at the bottom of the storage tank 11. A valve is installed on the quick-drainage line L2; opening this valve during the drying process allows the processing liquid in the storage tank 11 to be quickly drained. A top cover 13 is located at the top of the chamber 1 for opening and closing the chamber 1. After the substrate w is moved into the chamber 1, the top cover 13 seals the chamber 1, forming a sealed space inside the chamber 1 for processing the substrate w.

[0028] The substrate lifting mechanism 2 is disposed in the chamber 1 and is used to hold the substrate w in a vertical position and drive the substrate w to move up and down between the liquid storage tank 11 and the drying position 12.

[0029] The fluid supply unit 3 includes a nozzle 31, a first supply pipe 32, and a second supply pipe 33. The first supply pipe 32 and the second supply pipe 33 supply purge gas and solvent to the chamber 1 respectively through the nozzle 31. Typically, the gas is an inert gas or nitrogen, and the solvent is IPA. The first supply pipe 32 is connected to a nitrogen supply source and is opened and closed through a nitrogen valve 34. The first supply pipe 32 is also equipped with a heater for heating the nitrogen to provide high-temperature nitrogen to the chamber 1. The second supply pipe 33 is connected to a vapor generating device 35 and is opened and closed through a vapor valve 36. When it is necessary to supply IPA to the chamber 1, nitrogen or an inert gas is typically supplied as a carrier gas to the vapor generating device 35, and IPA is simultaneously supplied to the vapor generating device 35. The vapor generating device 35 heats the IPA to form vapor. The IPA vapor mixes with the nitrogen and is supplied to the nozzle 31 through the second supply pipe 33 at a given temperature. In some embodiments, the number of nozzles 31 may be multiple.

[0030] The fluid discharge unit 4 includes a fluid discharge pipe 41 located at the bottom of chamber 1. Fluid discharge pipe 41 is used to discharge nitrogen gas, IPA vapor, and treatment liquid from chamber 1. One end of fluid discharge pipe 41 is connected to the bottom of chamber 1, and the other end is connected to a buffer tank 42, which is used to recover the treatment liquid discharged from chamber 1. Buffer tank 42 is also connected to an exhaust pipe L3 and a liquid discharge pipe L4, used to discharge the gas and liquid within buffer tank 42, respectively. Both exhaust pipe L3 and liquid discharge pipe L4 are opened and closed by valves.

[0031] The pressure reducing unit 5 is connected to the fluid discharge pipe 41. Specifically, the pressure reducing unit 5 is a vacuum pump used to draw negative pressure into the chamber 1.

[0032] The detection unit 6 is used to detect the content of each component in the mixed fluid in the chamber 1. Specifically, the detection unit 6 can be a concentration meter for IPA vapor or water vapor, which is installed in the chamber 1 to detect the content of IPA vapor or water vapor in the chamber 1.

[0033] In other embodiments, the detection unit 6 may also be a residual gas analyzer (RGA) installed on the fluid discharge pipe 41. The RGA characterizes the content of each component in the mixed fluid in the chamber 1 by detecting the content of each component in the mixed fluid in the fluid discharge pipe 41. The residual gas analyzer can be used to detect the content of organic solvents (e.g., IPA) in the mixed fluid discharged from the chamber 1 in real time.

[0034] In other embodiments, the detection unit 6 may also be a pressure gauge, which is disposed in the chamber 1 to detect the internal pressure of the chamber 1.

[0035] This application also proposes a substrate drying method, which can be performed in the aforementioned substrate drying apparatus. Figure 2 A flowchart of the substrate drying method in this embodiment is shown. Specifically, the substrate drying method proposed in this embodiment will be described in detail below according to the substrate drying process sequence.

[0036] Step S100, substrate loading and nitrogen purging: The substrate is sent into the chamber and held in a dry position by the substrate lifting mechanism; pure water is supplied to the liquid storage tank, and at the same time the nitrogen valve is opened to supply nitrogen into the chamber to keep the environment inside the drying chamber dry and clean.

[0037] Step S200, pure water washing: Pure water is continuously supplied to the storage tank, and the substrate is lowered into the storage tank by the substrate lifting mechanism. The substrate is washed with pure water. The pure water in the storage tank overflows from the tank opening and is discharged from the fluid discharge pipe at the bottom of the chamber.

[0038] Step S300, IPA liquid level replacement: Close the nitrogen valve, open the steam valve, and supply IPA vapor to the chamber at a first flow rate through the steam generating device; within a given time, the liquid level of pure water is replaced by IPA vapor.

[0039] Step S400, IPA replacement on the substrate surface: IPA vapor is continuously supplied to the chamber at a first flow rate, and the substrate is raised to the drying position by the substrate lifting mechanism. The IPA vapor begins to replace the pure water adhering to the substrate surface. After the substrate reaches the drying position, IPA vapor is supplied to the chamber at a second flow rate, and the quick-drain pipe at the bottom of the storage tank is opened to quickly discharge the processing liquid in the storage tank, avoiding excessive water vapor generation in the chamber during subsequent depressurized drying. The second flow rate is greater than the first flow rate. During the process of the substrate rising from the storage tank to the drying position, the flow rate of IPA vapor is the first flow rate. When the substrate reaches the drying position, the flow rate of IPA vapor is increased to the second flow rate. This is to prevent the substrate from shaking due to excessive gas flow during the substrate's ascent, and to accelerate the rate of IPA replacement on the substrate surface after the substrate stabilizes.

[0040] In step S400, the second flow rate can be adjusted according to the number of substrates; the more substrates, the higher the second flow rate. The number of substrates and the corresponding second flow rate are preset in the program. The control unit automatically identifies the number of substrates in the chamber and supplies IPA vapor to the chamber at the second flow rate corresponding to that number. For example, when there are 25 substrates in the chamber, the second flow rate is 100 L / min; when there are 50 substrates, the second flow rate is 200 L / min.

[0041] Step S500, vacuum drying: as follows Figure 3 As shown, step S500 specifically includes the following steps:

[0042] S510, open the pressure reduction unit to reduce pressure in the chamber;

[0043] S520 acquires the detection data of the detection unit in real time. The detection data includes any one or more of the following: chamber pressure value, water vapor content value, and IPA vapor content value.

[0044] S530: Determine whether the detection data is lower than the preset threshold. If yes, shut down the decompression unit; otherwise, proceed to step S520.

[0045] In step S510, the vacuum pump acts as a pressure reduction unit, creating negative pressure within the chamber to reduce its pressure. Before executing step S510, the vapor valve and quick-release pipeline must be closed, and the nitrogen valve opened to supply nitrogen into the chamber, thus blowing out the IPA vapor.

[0046] In step S500, the pressure inside the chamber is reduced to accelerate the replacement of IPA on the substrate surface and the evaporation of IPA on the substrate surface. Furthermore, the exhaust pipe is closed during negative pressure extraction to prevent backflow of gas from the exhaust pipe and to prevent external contaminants from being drawn into the chamber through the exhaust pipe.

[0047] The types of detection data and preset thresholds are determined according to actual process requirements. In some embodiments, the detection data is the IPA vapor content value, obtained through RGA. In other embodiments, when the detection data includes multiple values ​​such as pressure, moisture content, and IPA vapor content, the vacuum pump can be shut off only after all multiple detection data are below the corresponding threshold. Specifically, when detecting the pressure value in the chamber, the corresponding threshold can be set to -90 kPa; when detecting the moisture content value, the corresponding threshold can be set to 0.01%; and when detecting the IPA vapor content value, the corresponding threshold can be set to 0.01%. In this embodiment, the negative pressure in the chamber is stopped only after the detection data is below the preset threshold. Compared with the method of automatically drawing negative pressure within a fixed time, it is easier to control the moisture or IPA vapor content in the chamber. The threshold can be flexibly set according to the actual process conditions to meet the requirements of moisture and IPA vapor content in different drying processes, effectively avoiding the adhesion and collapse of the substrate surface pattern structure.

[0048] Step S600, Pressure Restoration: Open the nitrogen valve to supply nitrogen into the chamber, restoring the internal pressure to atmospheric pressure. In this step, after the internal pressure is restored to a slightly positive pressure, open the quick-release pipe and exhaust pipe to maintain the internal pressure of the chamber in balance with atmospheric pressure, avoiding safety issues caused by excessive internal pressure when the chamber door is opened later.

[0049] Step S700, substrate removal: Remove the substrate from the cavity.

[0050] The substrate drying apparatus and method proposed in this application only stop drawing negative pressure into the chamber after the detected data falls below a preset threshold. Compared to the automatic negative pressure drawing method within a fixed time, this makes it easier to control the moisture or IPA vapor content in the chamber. The threshold can be flexibly set according to the actual process conditions to meet the moisture and IPA vapor content requirements of different drying processes, effectively preventing the adhesion and collapse of the substrate surface pattern structure. Moreover, this drying apparatus and method are not only applicable to ultra-low pressure drying processes but also to Marangoni drying processes, thus having a wide range of applications.

[0051] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A substrate drying apparatus, characterized in that, include: A chamber for providing a sealed space for processing a substrate, the chamber including a liquid reservoir for containing processing liquid and the substrate; A fluid supply unit for supplying solvent vapor into the chamber; A pressure reduction unit is used to reduce the pressure in the chamber; A detection unit is used to acquire detection data, which includes any one or more of the following: chamber pressure value, liquid vapor content value, and solvent vapor content value; The control unit is configured to: after the decompression unit is turned on, control the detection unit to acquire the detection data in real time, determine whether the detection data is lower than a preset threshold, and if the detection data is lower than the preset threshold, turn off the decompression unit.

2. The substrate drying apparatus according to claim 1, characterized in that, The chamber also includes a drying position and a substrate lifting mechanism. The drying position is located above the liquid storage tank, and the substrate lifting mechanism supports the substrate and drives the substrate to move up and down between the liquid storage tank and the drying position.

3. The substrate drying apparatus according to claim 1, characterized in that, It also includes a fluid discharge unit for discharging the treatment liquid and vapor from the chamber; the fluid discharge unit includes an exhaust pipe and a drain pipe.

4. The substrate drying apparatus according to claim 1, characterized in that, The treatment solution is pure water.

5. The substrate drying apparatus according to claim 1, characterized in that, The solvent is IPA.

6. A substrate drying method, applied to the substrate drying apparatus according to any one of claims 1-5, characterized in that, The process includes a depressurization drying step, which includes: after opening the depressurization unit to depressurize the chamber, acquiring the detection data of the detection unit in real time, determining whether the detection data is lower than a preset threshold, and if so, closing the depressurization unit; wherein, the detection data includes any one or more of the chamber pressure value, the processing liquid vapor content value, and the solvent vapor content value.

7. The substrate drying method according to claim 6, characterized in that, The pressure reduction drying process is followed by a pressure reduction process, which includes supplying purge gas into the chamber to reduce the internal pressure of the chamber to atmospheric pressure.

8. The substrate drying method according to claim 7, characterized in that, Once the internal air pressure of the chamber reaches a positive pressure, open the exhaust pipe.

9. The substrate drying method according to claim 6, characterized in that, Prior to the reduced pressure drying process, a solvent replacement process for the substrate surface is also included. The solvent replacement process for the substrate surface includes: supplying solvent vapor into the chamber at a first flow rate and raising the substrate from the liquid storage tank in the chamber to the drying position by a substrate lifting mechanism; after the substrate reaches the drying position, supplying solvent vapor into the chamber at a second flow rate; wherein the second flow rate is greater than the first flow rate.

10. The substrate drying method according to claim 9, characterized in that, The solvent replacement process on the substrate surface further includes: identifying the number of substrates in the chamber and adjusting the value of the second flow rate according to a preset correspondence between the number of substrates and the second flow rate.

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