Substrate processing apparatus and substrate processing method

Abstract

To provide a substrate processing apparatus and a substrate processing method that, when removing liquid adhering to a substrate surface by batch processing, can reduce the occurrence of pattern collapse by controlling the film thickness of a solidified film in accordance with the temperature of the processing liquid.SOLUTION: A substrate processing apparatus 1 includes a processing tank 11 that stores a processing liquid containing a sublimable substance and a solvent, a holding unit 20 that raises and lowers a group of substrates W relative to the processing tank 11 while holding them collectively, a lifting mechanism 23 that raises and lowers the holding unit 20 relative to the processing tank 11 to immerse the substrates in the processing liquid or remove them from the processing liquid, a processing liquid temperature measuring unit 40 that measures the temperature of the processing liquid stored in the processing tank 11, and a control unit 31 that controls the lifting mechanism 23, and the lifting mechanism 23 lifts the group of substrates W collectively from the processing liquid while evaporating the solvent, thereby precipitating the sublimable substance and forming a solidified film, and the control unit 31 controls the lifting speed of the substrates W such that a solidified film of the target thickness is formed according to the temperature of the processing liquid.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a substrate processing apparatus and a substrate processing method capable of collectively performing sublimation drying by batch processing on a plurality of substrates on which a stacked body such as a three-dimensional NAND structure is formed.

Background Art

[0002] In the manufacturing process of a semiconductor device, in the steps of wet etching and surface cleaning, a processing liquid is supplied to the substrate surface, and then a process of drying the substrate surface is performed. However, for example, when a pattern with a large aspect ratio is formed on the substrate surface, there is a concern that when the processing liquid is dried, force acts on the pattern due to the Laplace pressure of the processing liquid, causing pattern collapse. In recent years, along with the miniaturization and development of next-generation devices using new materials, techniques for suppressing the collapse of patterns formed on substrate surfaces have been demanded. Here, the sublimation drying technique, in which a processing liquid is solidified to form a solidified film, and then the solidified film is sublimated and removed, can prevent or reduce the action of Laplace pressure derived from the processing liquid on the pattern. Therefore, this technique is regarded as promising as a technique capable of suppressing pattern collapse.

[0003] The sublimation drying technique in substrate processing is being established for single-wafer processing that processes substrates one by one (for example, Patent Document 1 below). However, sufficient sublimation drying techniques have not been established for batch processing that processes a plurality of substrates collectively. For example, in a three-dimensional NAND structure such as a three-dimensional NAND flash memory, batch-type phosphoric acid treatment is required, but if the sublimation drying technique is not used, pattern collapse is a concern. Therefore, establishment of a batch-type sublimation drying technique is required. However, when sublimation drying of the substrate surface is performed by a batch method, if the film thickness of the solidified film formed on the substrate surface is not appropriate according to the structure of the pattern or the like, there is a problem that non-uniform stress is applied to the pattern when sublimating the solidified film, resulting in pattern collapse.

Prior Art Literature

Patent Literature

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-70873 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a substrate processing apparatus and a substrate processing method that can reduce or prevent the collapse of patterns by controlling the thickness of the solidified film according to the temperature of the processing liquid when removing liquid adhering to the surface of a substrate by batch processing. [Means for solving the problem]

[0006] The substrate processing apparatus according to the present invention is a substrate processing apparatus for processing the surface of a substrate in order to solve the above problems, comprising: a processing tank for storing a processing liquid containing a sublimable substance and a solvent; a holding unit for holding a plurality of substrates in an upright position collectively; a lifting mechanism for raising and lowering the holding unit relative to the processing tank to immerse the holding unit in the processing liquid or remove it from the processing liquid; a processing liquid temperature measuring unit for measuring the temperature of the processing liquid stored in the processing tank; and a control unit for controlling the lifting mechanism, wherein the immersion and removal are performed by immersing a plurality of substrates in the processing liquid The method involves evaporating the solvent while simultaneously lifting the plates to precipitate the sublimable substance, thereby forming a solidified film containing the sublimable substance on the surface of the substrate. The control unit controls the lifting mechanism to lift a plurality of the substrates at a lifting speed based on the film formation conditions, according to the target film thickness of the solidified film to be formed on the surface of the substrates. The film formation conditions are characterized by defining the lifting speed of the substrates according to the temperature of the processing liquid measured by the processing liquid temperature measuring unit, so that a solidified film of the target thickness is formed.

[0007] According to the above configuration, a processing solution containing a sublimable substance and a solvent is stored in the processing tank, and multiple substrates are held in an upright position in the holding section. The lifting mechanism allows the holding section, which holds the multiple substrates, to be raised and lowered relative to the processing tank. Therefore, in the above configuration, after immersing multiple substrates together in the processing solution containing a sublimable substance and a solvent, the multiple substrates are simultaneously pulled out of the processing solution in an upright position. During this pulling process, the solvent is evaporated and the sublimable substance is precipitated, forming a solidified film on the surface of each substrate. Here, the inventors of the present invention have found that the thickness of the solidified film formed on the substrate surface can be controlled by adjusting the speed at which the substrates are pulled out according to the temperature of the processing solution stored in the processing tank. That is, the higher the temperature of the processing solution, the higher the temperature of the substrates immersed in the processing solution. As a result, when the substrates are pulled out of the processing solution, the temperature of the meniscus portion in contact with the substrate surface can be increased. On the other hand, the liquid surface portion of the processing solution is in contact with the outside air and therefore has a lower temperature. Therefore, the surface tension in the meniscus becomes lower than the surface tension of the liquid surface, and a so-called Marangoni flow occurs, in which the processing liquid on the substrate surface is drawn into the processing liquid on the processing tank side. The occurrence of this Marangoni flow affects the degree to which the processing liquid is drained from the substrate surface. Accordingly, in the above configuration, by controlling the lifting speed of the substrate by the lifting mechanism according to the temperature of the processing liquid measured by the processing liquid temperature measuring unit, a solidified film with a target thickness can be formed with high precision.

[0008] In the above configuration, the system further includes a storage unit for storing the film formation conditions, the storage unit storing the temperature of the processing liquid, the target film thickness of the solidified film to be formed, and the pulling speed, each of which is associated with the temperature of the processing liquid, as the film formation conditions, and the control unit preferably determines the pulling speed of the substrate by referring to the film formation conditions retrieved from the storage unit, based on the target film thickness of the solidified film to be formed and the value of the temperature of the processing liquid measured by the processing liquid temperature measuring unit.

[0009] Furthermore, the substrate processing method according to the present invention is a substrate processing method for processing the surface of a substrate in order to solve the above problems, and includes the steps of immersing a plurality of substrates together in a processing liquid containing a sublimable substance and a solvent, then evaporating the solvent while simultaneously pulling up the plurality of substrates in an upright position to precipitate the sublimable substance, thereby forming a solidified film containing the sublimable substance on the surface of the substrates, wherein the formation of the solidified film is carried out by controlling the pulling up of the plurality of substrates at a pulling speed based on film formation conditions according to the target film thickness of the solidified film to be formed on the surface of the substrates, and the film formation conditions are characterized in that the pulling speed of the substrates is defined according to the measured temperature of the processing liquid so as to form a solidified film of the target film thickness.

[0010] According to the above configuration, after immersing multiple substrates simultaneously in a processing solution containing a sublimable substance and a solvent, when the multiple substrates are simultaneously removed from the processing solution in an upright position, the solvent is evaporated and the sublimable substance is precipitated, forming a solidified film on the surface of each substrate. Here, the inventors of the present invention have found that by adjusting the substrate removal speed according to the temperature of the processing solution, it is possible to control the thickness of the solidified film formed on the substrate surface. That is, the higher the temperature of the processing solution, the higher the temperature of the substrates immersed in the processing solution, and as a result, the temperature of the meniscus portion in contact with the substrate surface can be increased when the substrates are removed from the processing solution. On the other hand, the liquid surface portion of the processing solution is in contact with the outside air and is therefore at a lower temperature. As a result, the surface tension in the meniscus portion becomes smaller than the surface tension of the liquid surface, and a so-called Marangoni flow occurs, in which the processing solution on the substrate surface flows as if being drawn towards the liquid surface. The occurrence of this Marangoni flow affects the degree to which the processing solution drains from the substrate surface. Therefore, with the above configuration, by controlling the substrate pulling speed according to the temperature of the processing liquid, a solidified film with a target thickness can be formed with high precision.

[0011] In the above configuration, the film formation conditions include the temperature of the processing liquid, the target thickness of the solidified film to be formed, and the pulling speed, each corresponding to the temperature of the processing liquid, and it is preferable that the pulling speed of the substrate is determined based on the target thickness of the solidified film to be formed and the measured temperature of the processing liquid, with reference to the film formation conditions. [Effects of the Invention]

[0012] According to the present invention, the formation of a solidified film is performed by immersing multiple substrates simultaneously in a processing solution containing a sublimable substance and a solvent, then simultaneously lifting the multiple substrates out of the processing solution in an upright position, while evaporating the solvent and precipitating the sublimable substance during this lifting process. Furthermore, the lifting speed of the substrates is controlled according to the temperature of the processing solution, based on the film formation conditions for the solidified film. Here, the film formation conditions define the lifting speed of the substrates so that a solidified film of a target thickness is formed according to the temperature of the processing solution. As a result, the present invention makes it possible to form a solidified film of an appropriate thickness according to the temperature of the processing solution, thereby preventing or reducing the occurrence of pattern collapse. Furthermore, since the present invention allows for the formation of a solidified film on multiple substrates simultaneously through batch processing, throughput can be improved compared to conventional substrate processing. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1(a) is an explanatory diagram showing the state of a substrate processing apparatus according to an embodiment of the present invention before a plurality of substrates are immersed in the processing liquid or after they have been removed from the processing liquid, and Figure 1(b) is an explanatory diagram showing the state in which a plurality of substrates are immersed in the processing liquid. [Figure 2] This is a schematic cross-sectional view of the processing tank of the solidification film forming section in a substrate processing apparatus according to an embodiment of the present invention. [Figure 3] This is a block diagram showing the schematic configuration of the processing liquid supply unit in a substrate processing apparatus according to an embodiment of the present invention. [Figure 4]This is a side view showing the schematic configuration of the holding section and the lifting mechanism in a substrate processing apparatus according to an embodiment of the present invention. [Figure 5] This is an explanatory diagram showing the schematic configuration of a control unit in a substrate processing apparatus according to an embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating how a solidified film is formed on the surface of a substrate after it has been removed from the processing liquid, according to an embodiment of the present invention. [Modes for carrying out the invention]

[0014] (Substrate processing equipment) A substrate processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

[0015] The substrate processing apparatus according to this embodiment can be used, for example, to process various types of substrates. Here, "substrate" refers to various types of substrates such as semiconductor substrates, photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, and magneto-optical disk substrates. The substrate processing apparatus of this embodiment is suitable, for example, for processing substrates on which a three-dimensional structure such as a three-dimensional NAND structure is formed on the surface.

[0016] The substrate processing apparatus of this embodiment is a batch-type substrate processing apparatus used for drying after cleaning. Specifically, the substrate processing apparatus 1 of this embodiment comprises at least a solidification film forming unit 10, a holding unit (lifter) 20, a lifting mechanism 23, a processing liquid temperature measuring unit 40, and a control unit 30 that controls each part of the substrate processing apparatus 1, as shown in Figures 1(a) and 1(b). Figure 1(a) is an explanatory diagram showing the state of the substrate processing apparatus 1 according to this embodiment before a plurality of substrates W are immersed in the processing liquid or after they have been removed from the processing liquid, and Figure 1(b) is an explanatory diagram showing the state in which a plurality of substrates W are immersed in the processing liquid.

[0017] The cured film forming unit 10 is a batch processing unit that collectively forms a cured film containing a sublimable substance on the surfaces of a plurality of substrates W (hereinafter may be referred to as "substrate W group"). The cured film is formed while drying the solvent of the processing liquid when taking out the substrate W group immersed in the processing liquid from the processing liquid (details will be described later). The cured film forming unit 10 includes a processing tank 11 capable of storing the processing liquid, and a processing liquid supply unit 15. Further, the cured film forming unit 10 may be provided with a processing liquid temperature adjustment unit 16 for adjusting the temperature of the processing liquid stored in the processing tank 11.

[0018] As shown in FIG. 2, the processing tank 11 includes an injection pipe 12 that supplies the processing liquid into the processing tank 11, an inner tank 13 that stores the processing liquid, and an outer tank 14 provided at the peripheral edge of the upper opening of the inner tank 13. The injection pipe 12 is provided at the bottom of the processing tank 11, and enables up-flow supply of the processing liquid to the inner tank 13. By storing the processing liquid inside, the inner tank 13 allows the substrate W group held by the holding unit 20 to be immersed in the processing liquid. Further, the outer tank 14 enables recovery of the processing liquid that has overflowed from the inner tank 13. FIG. 2 is a cross-sectional view schematically showing the processing tank 11 of the cured film forming unit 10 in the substrate processing apparatus 1 of the present embodiment.

[0019] The processing liquid contains at least a sublimable substance and a solvent. The sublimable substance is preferably dissolved in the solvent in the processing liquid. The processing liquid functions to assist the drying process for removing the liquid present on the surface of the substrate W. In this specification, "sublimable" means that a simple substance, compound or mixture has a property of phase transition from solid to gas or from gas to solid without going through a liquid state, and "sublimable substance" means a substance having such sublimability.

[0020] Examples of the sublimable substance include t-butanol, camphor, naphthalene, cyclohexane, cyclohexanol, cyclohexanone oxime, pinacoline oxime, 4-tert-butylphenol, and the like. The solvent is not particularly limited as long as the sublimable substance has solubility therein, but a solvent having a vapor pressure at 20°C of 500 Pa or more and 90 kPa or less (preferably 2000 Pa or more and 65 kPa or less, more preferably 4000 Pa or more and 30 kPa or less) is preferable. More specific examples of the solvent include isopropyl alcohol (IPA), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether (PGEE), propylene glycol monomethyl ether (PGME), acetone, benzene, t-butanol, toluene, ethanol, methanol, and the like. Among these solvents, a solvent having a high vapor pressure such as IPA is preferable in the present embodiment.

[0021] The concentration of the sublimable substance in the treatment liquid can be appropriately set as needed. The concentration of the sublimable substance is usually 0.2% by mass or more and 40% by mass or less, preferably 0.4% by mass or more and 11.4% by mass or less, more preferably 0.6% by mass or more and 4% by mass or less, relative to the total mass of the treatment liquid.

[0022] Regarding the temperature of the treatment liquid in the treatment tank 11 (that is, the temperature measured by the treatment liquid temperature measurement unit 40), the lower limit thereof is preferably normal temperature or higher than the precipitation temperature at which the sublimable substance starts to precipitate in the treatment liquid. Further, the upper limit thereof is preferably a temperature lower than the boiling point of the treatment liquid or the solvent contained in the treatment liquid. This can suppress a change in the concentration of the treatment liquid. In addition, for example, when the treatment liquid is IPA, the temperature of the treatment liquid in the treatment tank 11 is more preferably 24°C or higher and 82°C or lower, and further preferably 50°C or higher and 75°C or lower.

[0023] The processing liquid supply unit 15 can supply processing liquid to the processing tank 11. Specifically, as shown in Figure 3, the processing liquid supply unit 15 includes at least a processing liquid storage unit 151, a temperature control unit 152, a pressurizing unit 153, piping 154, and a valve 155. Figure 3 is a block diagram showing the schematic configuration of the processing liquid supply unit 15.

[0024] The processing liquid storage section 151 can store the processing liquid. The processing liquid storage section 151 may be equipped with a stirring section for stirring the processing liquid stored inside. The stirring section is not particularly limited, and known types such as those equipped with propeller-shaped stirring blades or circulation pumps can be used. When a stirring section is provided, the stirring section is electrically connected to the control unit 30. As a result, the stirring section can stir the processing liquid in the processing liquid storage section 151 based on the operation commands of the control unit 31 in the control unit 30. By stirring the processing liquid, the concentration of sublimable substances and the temperature of the processing liquid can be made uniform.

[0025] The temperature control unit 152 heats the processing liquid in the processing liquid storage unit 151 to adjust its temperature. By adjusting the temperature of the processing liquid, it is possible to prevent, for example, the precipitation of sublimable substances in the processing liquid storage unit 151 and the resulting change in the concentration of the processing liquid. Furthermore, it is preferable that the upper limit of the temperature adjustment of the processing liquid be lower than the boiling point of the processing liquid or the solvent contained in the processing liquid. The temperature control unit 152 is electrically connected to the control unit 30 and adjusts the temperature of the processing liquid based on the operation command of the control unit 31 in the control unit 30. Specifically, the temperature control unit 152 can use known temperature adjustment mechanisms such as a resistance heater, a Peltier element, or piping through which temperature-adjusted water passes. However, if a processing liquid containing a solvent with a high vapor pressure is used, the solvent can be easily evaporated during the formation of the solidified film without heating the processing liquid. In such cases, the temperature control unit 152 may be omitted.

[0026] The pressurizing unit 153 pressurizes the inside of the processing liquid storage unit 151, thereby pumping the processing liquid stored in the processing liquid storage unit 151 to the processing tank 11. The pressurizing unit 153 may include, for example, a gas tank for storing gas, a pump for pressurizing the gas, and piping for supplying the gas to the processing liquid storage unit 151. The gas tank is connected to the processing liquid storage unit 151 via piping. A pump is also inserted into the piping. The pump is electrically connected to the control unit 30, and the control unit 31 in the control unit 30 can supply the gas stored in the gas tank to the processing liquid storage unit 151 via the piping. This allows for adjustment of the pressure inside the processing liquid storage unit 151, enabling the pumping of the processing liquid to the processing tank 11. It is preferable to use an inert gas, such as nitrogen gas, that does not react with the processing liquid. Furthermore, since the processing liquid in the processing liquid storage section 151 is pumped using gas pressure, it is preferable that the processing liquid storage section 151 be configured to be highly airtight.

[0027] The pipe 154 is connected by pipeline to the treatment liquid storage section 151 at one end. At the other end, it is connected by pipeline to the injection pipe 12 of the treatment tank 11.

[0028] Valve 155 is located in the middle of the piping 154. Valve 155 is electrically connected to the control unit 30 and is normally closed. The opening and closing of valve 155 is controlled by the control unit 31 in the control unit 30. For example, when the control unit 31 issues an operation command, the pump of the pressurizing unit 153 supplies gas to the processing liquid storage unit 151 and valve 155 is opened, causing the pressurized processing liquid in the processing liquid storage unit 151 to be pumped and supplied to the injection pipe 12 of the processing tank 11 via piping 154.

[0029] As shown in Figure 4, the holding part (lifter) 20 comprises a flat back plate portion 21 and a plurality (3) of holding rods 22. The holding part 20 is a member configured to support a plurality of substrates W in an upright position by contacting them from below. Figure 4 is a side view showing the schematic configuration of the holding part 20 and the lifting mechanism 23 in the substrate processing apparatus 1 of this embodiment. The back plate portion 21 is erected, and at its lower end, the holding rods 22 extend in one direction perpendicular to the back plate portion 21. The holding rods 22 are provided with a plurality of grooves 24 arranged in the direction of their extension. Furthermore, the plurality of grooves 24 are spaced apart from each other and arranged at equal intervals. In addition, each groove 24 extends in a direction perpendicular to the direction of extension of the holding rod 22, allowing a plurality of substrates W to be fitted in an upright position. As a result, the holding rods 22 contact and support the group of substrates W from below in an upright position, making it possible to hold the group of substrates W collectively. The number of holding rods 22 is not particularly limited, as long as there are multiple rods. The number of grooves 24 provided on the holding rods 22 is also not particularly limited and can be set appropriately according to the number of substrates W to be held. Furthermore, in this specification, "upright position" means a position in which the surface (main surface, pattern forming surface) of the substrate W is aligned approximately vertically with respect to the horizontal plane, and includes the case of a vertical position.

[0030] As shown in Figure 4, the lifting mechanism 23 comprises a connecting member 25, a lifting support column 26, a ball screw 27, a lifting base 28, and a motor 29. The connecting member 25 extends from the back surface of the upper end of the back plate portion 21 in a direction perpendicular to the back plate portion 21 (parallel to the direction indicated by arrow Y). The lifting support column 26 is attached to the lower surface of the connecting member 25 at its upper end. The lifting support column 26 is also attached to the lifting base 28 at its lower end. The ball screw 27 is connected to the rotation shaft of the motor 29. The ball screw 27 is screwed through the lifting base 28. The motor 29 is electrically connected to the control unit 30.

[0031] The lifting mechanism 23 can raise or lower the holding section 20 in the X direction shown in Figures 1(a), 1(b), and 4, in response to an operation command from the control unit 31 in the control unit 30. More specifically, when the motor 29 receives an upward operation command from the control unit 30 and is driven, the ball screw 27 rotates, and the lifting column 26 rises together with the lifting base 28. Accordingly, the back plate section 21 also rises via the connecting member 25 connected to the lifting column 26. Conversely, when the motor 29 receives a downward operation command from the control unit 30 and is driven in the opposite direction, the ball screw 27 rotates in the opposite direction, and the lifting column 26 descends together with the lifting base 28. Accordingly, the back plate section 21 also descends via the connecting member 25 connected to the lifting column 26. In this way, by raising and lowering the back plate portion 21 while the substrate group W is supported from below by the holding rod 22, the holding portion 20, which holds the substrate group W as a whole, can be moved into or removed from the processing tank 11. More specifically, the lifting mechanism 23 raises and lowers the holding portion 20 between the retracted position shown in Figure 1(a) and the processing position shown in Figure 1(b). In Figure 1(a), the holding portion 20 holding the substrate group W is in a retracted position above the processing tank 11 so as not to be immersed in the processing liquid. In Figure 1(b), the holding portion 20 holding the substrate group W is in a processing position inside the processing tank 11 so as to be immersed in the processing liquid stored in the inner tank 13 of the processing tank 11. In this specification, "retracted position" means a position above the processing tank 11 where at least the holding portion 20 does not come into contact with the surface of the processing liquid. Furthermore, in this specification, "processing position" means a position within the inner tank 13 of the processing tank 11 where the group of substrates W are completely immersed in the processing liquid.

[0032] The processing liquid temperature adjustment unit 16 can adjust the temperature of the processing liquid stored in the inner tank 13 of the processing tank 11. As shown in Figures 1(a) and 1(b), the processing liquid temperature adjustment unit 16 is electrically connected to the control unit 30 and adjusts the temperature of the processing liquid stored in the processing tank 11 in accordance with operation commands from the control unit 31 of the control unit 30. The processing liquid temperature adjustment unit 16 is not particularly limited, and known temperature adjustment mechanisms such as a Peltier element or piping through temperature-controlled water can be used.

[0033] The processing liquid temperature measuring unit (thermometer) 40 measures the temperature of the processing liquid stored inside the inner tank 13 (see Figures 1(a), 1(b), and 2).

[0034] The processing liquid temperature measuring unit 40 may be composed of, for example, a thermocouple. The processing liquid temperature measuring unit 40 is electrically connected to the control unit 30 and can transmit measurement data regarding the temperature of the processing liquid to the control unit 30.

[0035] The position of the processing liquid temperature measuring unit 40 within the inner tank 13 is not particularly limited, but a position that does not obstruct the raising and lowering of the holding unit 20 is preferred. Furthermore, the position where the processing liquid temperature measuring unit 40 measures the temperature of the processing liquid is preferably near the liquid surface of the processing liquid, taking into consideration the possibility of a temperature distribution occurring in the processing liquid stored in the inner tank 13. This makes it possible to determine a temperature close to that of the meniscus portion of the processing liquid that is in contact with the substrate surface and where Marangoni flow may occur.

[0036] Furthermore, the processing liquid temperature measuring unit 40 may measure the temperature of the processing liquid at multiple different locations within the inner tank 13. Alternatively, the processing liquid temperature measuring unit 40 may be placed at multiple different locations within the inner tank 13 for measurement. By measuring the temperature of the processing liquid at multiple different locations within the inner tank 13, the uniformity of the temperature of the processing liquid stored in the inner tank 13 can be confirmed and evaluated. The measured temperature may be expressed as the average value of the temperatures measured at multiple different locations. In this case, the average value can be calculated using an arithmetic mean, a weighted mean, or the like.

[0037] The control unit 30 is electrically connected to each part of the substrate processing apparatus 1 and controls the operation of each part. The control unit 30 has at least a control unit 31, a storage unit 32, and an input unit 33, as shown in Figure 5. Figure 5 is an explanatory diagram showing the schematic configuration of the control unit 30 in the substrate processing apparatus 1 of this embodiment.

[0038] The control unit 31 is not particularly limited; for example, a CPU (Central Processing Unit) or MPU (Micro Processing Unit) that performs various calculations can be used. The storage unit 32 includes a ROM (read-only memory) for storing the basic program, a RAM (read-write memory) for storing various information, and a magnetic disk for storing control software and data. The magnetic disk has pre-stored substrate processing conditions corresponding to the substrate W. The magnetic disk also stores film formation conditions corresponding to the processing solution (details will be described later). The control unit 31 reads the substrate processing program from the storage unit 32 and controls each part of the substrate processing apparatus 1 according to its contents. The input unit 33 can be, for example, a keyboard or mouse. Data input from the input unit 33 is received by the control unit 31 and can be stored in the storage unit 32 as needed.

[0039] The control unit 31 adjusts the pressure in the processing liquid storage unit 151 by controlling the pump in the pressurization unit 153 of the processing liquid supply unit 15 based on the substrate processing conditions read from the memory unit 32. This pressure adjustment allows control of the amount of processing liquid supplied from the processing liquid storage unit 151 to the processing tank 11. The control unit 31 also controls the opening and closing of the valve 155 in the processing liquid supply unit 15 based on the substrate processing conditions. This allows the control unit 31 to control the timing of the processing liquid supply. Furthermore, if an agitator is provided in the processing liquid storage unit 151, the control unit 31 also controls the agitator based on the substrate processing conditions.

[0040] Furthermore, the control unit 31 instructs the temperature adjustment unit 152 to adjust the temperature in the processing liquid storage unit 151 based on the substrate processing conditions read from the memory unit 32. This temperature adjustment allows control of the liquid temperature of the processing liquid that is pumped from the processing liquid storage unit 151 to the processing tank 11.

[0041] Furthermore, the control unit 31 can instruct the processing liquid temperature adjustment unit 16 to adjust the temperature of the processing liquid stored in the processing tank 11 based on the film deposition conditions read from the storage unit 32. More specifically, the control unit 31 compares the temperature of the processing liquid set in the film deposition conditions (hereinafter sometimes referred to as the "set temperature") with the temperature of the processing liquid in the processing tank 11 measured by the processing liquid temperature measurement unit 40 (hereinafter sometimes referred to as the "measured temperature"). For example, if the measured temperature of the processing liquid has not reached the set temperature, the control unit 31 issues an operation command to the processing liquid temperature adjustment unit 16 to heat the processing liquid in the processing tank 11.

[0042] Furthermore, the control unit 31 raises and lowers the holding unit 20 by controlling the raising and lowering operation of the lifting mechanism 23 based on the film deposition conditions read from the storage unit 32 and the temperature of the processing liquid measured by the processing liquid temperature measurement unit 40. In addition, the control unit 31 controls the speed at which the holding unit 20 rises based on the film deposition conditions by controlling the raising and lowering operation of the lifting mechanism 23. This controls the lifting speed of the group of substrates W held collectively in the holding unit 20.

[0043] Here, the film formation conditions stored in the memory unit 32 define the pulling speed of the substrate W group so that a solidified film of a target thickness (hereinafter sometimes referred to as "target film thickness") is formed, according to the temperature of the processing liquid in the processing tank 11 measured by the processing liquid temperature measurement unit 40. More specifically, the film formation conditions include the temperature of the processing liquid stored in the processing tank 11, the target film thickness of the solidified film to be formed, and the pulling speed of the substrate W, each of which is associated with the temperature of the processing liquid.

[0044] In this embodiment, the following reasons are used for the film formation conditions. Specifically, as shown in Figure 6, for example, when a substrate W is immersed in a processing solution 37 containing a solvent with a high vapor pressure, and then the substrate W is withdrawn, the solvent contained in the processing solution 37 evaporates from the surface of the substrate W at the same time as the substrate is withdrawn. As a result, a solute such as a sublimable substance 38 precipitates on the surface of the substrate W due to the evaporation of the solvent, and a solidified film 36 containing the sublimable substance 38 is formed. Figure 6 is a schematic diagram illustrating the formation of a solidified film 36 on the surface of a substrate W after it has been withdrawn from the processing solution 37.

[0045] Here, there exists a relationship between the thickness of the solidified film 36 and the pulling speed of the substrate W, which can be expressed by the following equation (1).

[0046]

number

[0047] According to equation (1) above, the thickness of the solidified film 36 can be increased by increasing the withdrawal speed of the substrate W. Conversely, the thickness of the solidified film 36 can be decreased by decreasing the withdrawal speed. On the other hand, when the physical properties of the processing liquid 37, such as viscosity and density, are kept constant, it has been found that the thickness of the solidified film 36 formed on the surface of the substrate W also differs when the temperature of the processing liquid 37 stored in the processing tank 11 changes. For example, if the temperature of the processing liquid 37 is increased, the substrate W immersed in the processing liquid 37 is heated and becomes hot. When the substrate W is withdrawn from the processing liquid 37 in this state, the meniscus portion where the processing liquid 37 is in contact with the surface of the substrate W also becomes hot, similar to the substrate W. On the other hand, the temperature of the liquid surface portion of the processing liquid 37 is lower than the internal temperature due to contact with the outside air. As a result, the surface tension in the meniscus portion of the processing liquid 37 is relatively lower than that of the liquid surface portion, resulting in uneven surface tension. Generally, when the surface tension of a liquid surface is uneven, a Marangoni flow occurs, where the liquid flows from areas of low surface tension to areas of high surface tension. In this invention, too, due to the unevenness of surface tension between the meniscus portion and the liquid surface portion, the meniscus portion of the processing liquid 37 tends to flow towards the processing tank 11. As a result, the liquid drainage of the processing liquid 37 from the substrate W surface is improved. Thus, the generation of a Marangoni flow in the meniscus portion affects the degree of liquid drainage of the processing liquid 37 from the substrate W surface. Therefore, in this embodiment, in order to form a solidified film of the target thickness, the pulling speed of the substrate W group is controlled according to the temperature of the processing liquid 37 in the processing tank 11 as a film formation condition for the solidified film.

[0048] In this specification, "lifting speed" refers to the speed at which the surface of the substrate W separates from the surface of the processing liquid. Therefore, when the height of the processing liquid level does not decrease and remains constant, the lifting speed refers to the rate at which the substrate W rises relative to the surface of the processing liquid. Furthermore, when the height of the processing liquid level decreases, the lifting speed is expressed as the sum of the rate at which the substrate W rises relative to the surface of the processing liquid and the rate at which the surface of the processing liquid decreases.

[0049] (Substrate processing method) Next, a substrate processing method using the substrate processing apparatus 1 of this embodiment will be described below with reference to the drawings. The substrate processing method of this embodiment includes at least a solidification film formation step.

[0050] First, the multiple substrates W are held in the holding unit 20 in the retracted position shown in Figure 1(a). At this time, the multiple substrates W are held in an upright position with respect to the horizontal plane.

[0051] Next, when the control unit 31 receives a film formation instruction from the input unit 33, it reads the film formation conditions from the storage unit 32. The control unit 31 also receives an output from the processing liquid temperature measurement unit 40 regarding the measured temperature of the processing liquid. Furthermore, the control unit 31 compares the measured temperature of the processing liquid 37 measured by the processing liquid temperature measurement unit 40 with the set temperature of the processing liquid in the film formation conditions read from the storage unit 32. If the measured temperature of the processing liquid 37 is lower than the set temperature, it issues an operation command to the processing liquid temperature adjustment unit 16 to heat the processing liquid 37 stored in the processing tank 11. The temperature adjustment by the processing liquid temperature adjustment unit 16 is performed until the measured temperature of the processing liquid 37 reaches the temperature of the processing liquid in the film formation conditions. If the measured temperature of the processing liquid is the same as the set temperature of the film formation conditions from the beginning, the operation command from the control unit 31 to the processing liquid temperature adjustment unit 16 can be omitted.

[0052] If the temperature measured by the processing liquid temperature measuring unit 40 is the same as the set temperature for the film deposition conditions, the control unit 31 operates the lifting mechanism 23 based on these film deposition conditions and lowers the holding unit 20 to the processing position shown in Figure 1(b), i.e., into the inner tank 13 of the processing tank 11. This immerses the group of substrates W, which are held in an upright position by the holding unit 20, into the processing liquid all at once. The lowering speed of the group of substrates W when immersing them in the processing liquid is not particularly limited, but it is preferable to keep it constant. Furthermore, it is preferable that the immersion time for immersing the group of substrates W in the processing liquid is, for example, until the group of substrates W is heated and its temperature becomes equal to the temperature of the processing liquid.

[0053] After immersion, the control unit 31 operates the lifting mechanism 23 based on the film formation conditions and the temperature measured by the processing liquid temperature measuring unit 40, raising the holding unit 20 to the retracted position shown in Figure 1(a), i.e., above the inner tank 13 of the processing tank 11. This lifts the group of substrates W in the upright position out of the processing liquid all at once.

[0054] The direction in which the substrate group W is lifted (the upward direction of the holding part 20) is not particularly limited, but it is preferably perpendicular to the liquid surface (horizontal plane) of the processing liquid.

[0055] When the substrate group W is removed from the processing solution, a solidified film is formed on the surface of the substrate group W at the time of removal. That is, for example, if a solvent with a high vapor pressure is used in the processing solution, as shown in Figure 6, when the substrate W is removed from the processing solution 37, the solvent contained in the processing solution 37 evaporates simultaneously on the surface of the substrate W. As a result, solutes such as sublimable substances 38 precipitate on the surface of the substrate W due to the evaporation of the solvent, and a solidified film 36 containing sublimable substances 38 is formed. Furthermore, even when a solvent with a low vapor pressure is used, the processing solution temperature adjustment unit 16 heats the processing solution 37 stored in the processing tank 11 to a high temperature in accordance with the operation command of the control unit 30, so that the solvent evaporates simultaneously with the removal of the substrate W, causing sublimable substances 38 to precipitate and a solidified film 36 to be formed.

[0056] The target film thickness of the solidified film to be formed is preferably set appropriately according to the shape and height of the pattern formed on the surface of the substrate W.

[0057] Here, the lifting speed of the substrate group W is determined by the control unit 30, for example, as follows. That is, when the temperature of the processing liquid 37 is measured in the processing liquid temperature measurement unit 40 and the target film thickness of the solidified film to be formed is input to the input unit 33, the control unit 31 reads out the film formation conditions from the storage unit 32. The read-out film formation conditions associate the temperature of the processing liquid 37, the target film thickness of the solidified film, and the lifting speed of the substrate W. Furthermore, based on the input target film thickness of the solidified film and the measured temperature of the processing liquid 37, the control unit 31 refers to the read-out film formation conditions and determines the lifting speed of the substrate group W. Subsequently, the control unit 31 issues an operation command to the lifting mechanism 23 based on the determined lifting speed, and the holding unit 20 performs the lifting of the substrate group W.

[0058] The lifting speed of the substrate group W may be constant from the start to the end of the lifting process, or it may be varied according to the lifting distance of the substrate group W, etc. If the lifting speed is kept constant, and there is no change in the physical properties of the processing liquid 37 (e.g., density, viscosity, etc.) over time, the uniformity of the thickness of the solidified film 36 can be controlled with high precision. As a result, the uneven application of stress to the pattern on the substrate W when forming the solidified film 36 or when sublimating the solidified film 36 can be reduced, and the occurrence of pattern collapse can be further reduced.

[0059] When the substrates W are being pulled out of the processing liquid 37, it is preferable that the liquid surface of the processing liquid 37 remains stationary. This ensures that the meniscus of the liquid surface of the processing liquid 37, formed by interaction with the surface of the substrates W, remains constant while the substrates W are being pulled out of the processing liquid 37, thereby enabling the formation of a solidified film 36 with even greater uniformity of film thickness.

[0060] Furthermore, the substrate group W is withdrawn from the processing solution 37 in an upright position. This method allows for the formation of a solidified film 36 by allowing the precipitated sublimable material 38 to crystallize in the plane. In other words, it prevents the precipitated sublimable material 38 from crystallizing in three dimensions, thereby preventing the occurrence of film defects caused by the generation of grain boundaries and reducing or preventing pattern collapse. Moreover, it is preferable that the upright position of the substrate group W is kept constant while being withdrawn from the processing solution 37. This makes it possible to form a solidified film 36 with even greater uniformity of film thickness. In addition, if the solidified film 36 is formed on the surface of the substrate W simultaneously with the withdrawal from the processing solution 37, the time during which stress caused by the formation of the solidified film 36 is applied to the pattern on the surface of the substrate W can be minimized. As a result, the occurrence of pattern collapse can be further reduced or prevented. Furthermore, in this embodiment, the formation of the solidified film 36 involves immersing the entire group of substrates W in the processing solution 37 at once. This allows for the simultaneous replacement of any remaining liquid organic compounds on the surface of each substrate W with the processing solution 37 for the entire group of substrates W. In particular, for substrates with three-dimensional structures such as three-dimensional NAND structures, the replacement of organic compounds in trenches formed perpendicular to the substrate surface and in the ON (oxide-nitride) structure extending horizontally from these trenches requires a significant amount of time. Therefore, processing multiple substrates W one by one using a single-wafer processing method would take a considerable amount of time. However, with this substrate processing method, since multiple substrates W are immersed in the processing solution 37 at once, the processing solution 37 can be replaced for multiple substrates W with such three-dimensional structures at once. As a result, processing can be completed in a significantly shorter time compared to processing multiple substrates W one by one using a single-wafer processing method. Furthermore, the amount of processing solution 37 used can be reduced compared to the case where the processing solution is replaced with the processing solution 37 using a single-wafer method.

[0061] When the substrate group W is lifted out of the processing liquid 37 all at once and the holding unit 20 returns to its retracted position, the solidification film formation process is completed.

[0062] As described above, in the substrate processing method of this embodiment, a solidified film 36 can be formed by immersing multiple substrates W in the processing liquid 37 all at once and then withdrawing them all at once from the processing liquid 37. Therefore, compared to the case in which a solidified film is formed on the substrate surface by a single-wafer method in which substrates are processed one by one, the throughput of substrate processing can be improved.

[0063] Furthermore, by adjusting the lifting speed of the substrate group W according to the temperature of the processing liquid 37 stored in the processing tank 11 while forming a solidified film 36 of the target thickness, the film thickness can be controlled with high precision. In addition, the uniformity of the film thickness of the formed solidified film 36 can be improved, so for example, when forming the solidified film 36 or when removing the solidified film 36 by sublimation, it is possible to prevent uneven stress from being applied to the pattern and to prevent or reduce the occurrence of pattern collapse.

[0064] Furthermore, as the surface of the substrate W separates from the liquid surface of the processing solution 37, the solvent evaporates and a sublimable substance precipitates, forming a solidified film 36. Therefore, unlike conventional methods, there is no need to perform a drying step to evaporate the solvent after applying the processing solution. [Explanation of Symbols]

[0065] 1...Substrate processing device, 10...Solidification film forming unit, 11...Processing tank, 12...Injection pipe, 13...Inner tank, 14...Outer tank, 15...Processing liquid supply unit, 16...Processing liquid temperature adjustment unit (thermometer), 20...Holding unit (lifter), 21...Back plate unit, 22...Holding rod, 23...Lifting mechanism, 24...Groove unit, 25...Connecting member, 26...Lifting support column, 27...Ball screw, 28...Lifting base, 29...Motor, 30...Control unit, 31...Control unit, 32...Storage unit, 33...Input unit, 36...Solidification film, 37...Processing liquid, 38...Sublimable substance, 40...Processing liquid temperature measurement unit, 151...Processing liquid storage unit, 152...Temperature adjustment unit, 153...Pressurization unit, 154...Piping, 155...Valve

Claims

1. A substrate processing apparatus for processing the surface of a substrate, A treatment tank for storing a treatment solution containing a sublimable substance and a solvent, A holding unit that holds multiple substrates in an upright position together, A lifting mechanism for raising and lowering the holding part relative to the processing tank to immerse the holding part in the processing liquid or remove it from the processing liquid, A processing liquid temperature measuring unit for measuring the temperature of the processing liquid stored in the processing tank, A control unit that controls the lifting mechanism, Equipped with, The aforementioned immersion and removal process is as follows: This method involves simultaneously removing multiple substrates immersed in the processing liquid while evaporating the solvent to precipitate the sublimable substance, thereby forming a solidified film containing the sublimable substance on the surface of the substrates. The control unit, The lifting mechanism is controlled to lift a plurality of substrates at a lifting speed based on the film formation conditions, according to the target film thickness of the solidified film to be formed on the surface of the substrate. The aforementioned film formation conditions define the substrate pulling speed so that a solidified film of the target thickness is formed, according to the temperature of the processing liquid measured by the processing liquid temperature measuring unit. Circuit board processing equipment.

2. The system further comprises a memory unit for storing the aforementioned film formation conditions, The aforementioned storage unit is The film formation conditions are stored as the temperature of the processing liquid, the target film thickness of the solidified film to be formed, and the pulling speed, each of which is associated with the temperature of the processing liquid. The control unit, The substrate lifting apparatus according to claim 1, wherein the substrate pulling speed is determined by referring to the film formation conditions retrieved from the storage unit, based on the target film thickness of the solidified film to be formed and the temperature value of the processing liquid measured by the processing liquid temperature measuring unit.

3. A substrate processing method for processing the surface of a substrate, The process includes immersing a plurality of substrates together in a processing solution containing a sublimable substance and a solvent, then evaporating the solvent while simultaneously lifting the plurality of substrates in an upright position to precipitate the sublimable substance, thereby forming a solidified film containing the sublimable substance on the surface of the substrates. The formation of the solidified film is The process is carried out by controlling the pulling speed of multiple substrates at a rate based on the film formation conditions, according to the target film thickness of the solidified film to be formed on the surface of the substrate. The aforementioned film formation conditions define the substrate pulling speed so that a solidified film of the target thickness is formed, according to the measured temperature of the processing liquid. Substrate processing method.

4. The film formation conditions include the temperature of the processing liquid, the target film thickness of the solidified film to be formed, and the pulling speed, each corresponding to the temperature of the processing liquid. The substrate processing method according to claim 3, wherein the formation of the solidified film is determined by referring to the film formation conditions, based on the target film thickness of the solidified film to be formed and the measured temperature of the processing liquid, to determine the lifting speed of the substrate.

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