JPH11186211A - Wafer treater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer treater, which can control accurately the descending speed of the level of pure water in a liquid discharge and drying treatment. SOLUTION: Pure water in a treating tank 1 is discharged through inner-tank liquid discharge pipes 109. During this discharge, an introducing tube 24 continues to feed IPA (isopropanol) vapor. As the liquid level of the pure water lowers by this discharge, a layer of IPA condensed on the liquid level of the pure water is deposited on each wafer W and as a result, droplets adhering to the surface of each wafer W are replaced by the condensed IPA layer. A control mechanism 6 detects the position of the liquid level of the pure water lowered by the discharge by a liquid level sensor 61 in the tank 1 and a micromanometer 62. The lowering speed of the liquid level of the pure water is calculated in an arithmetic circuit 63 on the basis of the position, which is measured by the sensor 61 and the micromanometer 62, of the liquid level. An electropnenmatic regulator 64 converts this calculation result into a pilot air pressure. A pressure adjuster 65 adjusts the opening of a quick open valve 66 by this pilot air pressure to control the flow rate of the pure water, which is discharged through the liquid discharge pipes 109.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus, and more particularly, to a silicon wafer, an FPD (Flat Panel Diode) in a semiconductor device manufacturing process, a liquid crystal display manufacturing process, an electronic component-related manufacturing process and the like.
The present invention relates to a substrate processing apparatus that performs chemical liquid processing, cleaning processing, and drain / dry processing (so-called drain drying) on various substrates such as a splay substrate, a photomask glass substrate, and electronic components.

[0002]

2. Description of the Related Art As a conventional substrate processing apparatus, for example,
One disclosed in Japanese Patent Publication No. 6-103686 is known. FIG. 19 is a view for explaining the configuration of a conventional substrate processing apparatus and a drainage / drying process. In a conventional substrate processing apparatus, as shown in FIG.
Various pipes and valves are connected to 1 and an etching process and other necessary processes are performed. Hereinafter, the processing executed by the substrate processing apparatus having the configuration shown in FIG.
This will be described with reference to FIG.

In FIG. 19B, first, a container 191 is set.
Inside, a plurality of substrates W are suspended so as to be aligned in a vertical direction in parallel. In such a state, the substrate processing apparatus supplies an etchant and other necessary chemicals from the fluid inlet 192 located at the upper part of the container 191 and discharges (drains) it from the fluid outlet 193 located at the lower part. as a result,
Each substrate W suspended in the container 191 is immersed in a chemical solution. The substrate processing apparatus performs the chemical liquid processing (for example, etching processing) on each substrate W in this manner, and executes the following drainage / drying processing.

In the drainage / drying process, the substrate processing apparatus supplies pure water or other cleaning liquid into the container 192 from the fluid inlet 192, and simultaneously discharges the chemical remaining in the container 192 from the fluid outlet 193. Thus, the chemical in the container 191 is replaced with pure water. After the inside of the container 191 is replaced with pure water, the substrate processing apparatus continues to discharge the pure water from the fluid outlet 193, but stops the supply of the pure water into the container 191. As a result, the container 191
The level of pure water in the interior begins to drop. Thereafter, the substrate processing apparatus supplies isopropanol vapor (hereinafter, referred to as IPA vapor) from the fluid inlet 192 to the liquid level of the pure water that is falling.

As the level of pure water drops, each substrate W
, An IPA layer condensed on the pure water surface adheres, and as a result, droplets adhering on the surface of each substrate W are replaced by the condensed IPA layer. Accordingly, the substrate processing apparatus can sufficiently dry each substrate W without leaving a droplet on the surface of each substrate W.

[0006]

In the above-described drainage / drying process, the degree of drying of the substrate W is determined by the speed at which the liquid level of the pure water is lowered in the container 191 (hereinafter, referred to as the descent speed). ) Is known, and this descent rate needs to be precisely controlled. In the substrate processing apparatus of the above publication, the descending speed is controlled based on the measurement result of the metering pump 194 connected to the flow path downstream of the fluid outlet 193. However, this metering pump 194
Since the liquid level of the pure water is not directly measured, the position of the liquid level of the pure water is not accurately detected. As a result, it is difficult for the substrate processing apparatus of the above publication to appropriately control the descent speed. There was a point.

[0007] Therefore, an object of the present invention is to provide a substrate processing apparatus capable of accurately controlling the descending speed when performing a drainage / drying process.

[0008]

Means for Solving the Problems and Effects of the Invention The first invention is a substrate processing apparatus for immersing a substrate contained in a processing bath in a cleaning liquid, cleaning the substrate, and then drying the substrate. A cleaning liquid supply unit for supplying a cleaning liquid to the processing tank and immersing the substrate accommodated in the processing tank in the cleaning liquid; and discharging the cleaning liquid stored in the processing tank to the outside to perform the processing. A discharge section for lowering the level of the cleaning liquid in the tank, a dry steam supply section for supplying a dry vapor for drying the substrate to a liquid level of the cleaning liquid lowered by the discharge section, and the processing tank And a detection unit for detecting a current position of the liquid surface descending in the processing tank, and the cleaning liquid discharged by the discharge unit based on a current position of the liquid surface detected by the detection unit. Control the flow rate of And a control unit. According to the first aspect, the control unit controls the flow rate of the cleaning liquid based on the current position of the liquid surface detected by the detection unit. As a result, the speed at which the cleaning liquid descends in the processing tank (hereinafter, referred to as the descending speed) is controlled. In such control of the descending speed, the detection unit directly measures the current position of the liquid level in the processing tank. Therefore, the current position of the liquid level is accurately measured. Thus, the first invention can more appropriately control the descending speed of the cleaning liquid in the processing tank.

According to a second aspect, in the first aspect, a support portion for supporting the substrate in the processing tank and storing the substrate at a predetermined position in the processing tank is provided. It has a threshold value set in advance in relation to the support portion of the substrate in the support portion, and when it is determined that the current position of the liquid level detected by the detection portion has reached the threshold value,
The flow rate of the cleaning liquid discharged from the discharge unit is controlled to be relatively small, so that the liquid surface falling speed in the processing tank is reduced. According to the second invention, the support portion supports the substrate in the processing tank as described above, but the support portion tends to have a complicated shape, and the cleaning liquid easily remains on the support portion. Therefore, according to the second aspect, the flow rate from the discharge unit is:
It is determined based on the threshold value as described above, and is reduced when the current position of the liquid level reaches the supporting portion of the substrate. Therefore, the descending speed is slow at the support portion, and the cleaning liquid is less likely to remain at the support portion. That is, if the descending speed is high, the cleaning liquid in the supporting portion is separated from the liquid surface and remains as liquid droplets. However, when the descending speed is low, the cleaning liquid in the supporting portion can be taken into the liquid surface by the surface tension of the liquid surface. Also, the supplied dry steam condenses on the liquid surface, but if the descent speed is reduced, this supporting portion is exposed to the condensed dry steam for a long time. Thus, according to the substrate processing apparatus of the second aspect, the substrate is sufficiently dried over the entire surface.

[0010] In a third aspect based on the first or second aspect, the processing chamber is housed, and the processing chamber houses a substrate, and the inside of the chamber is hermetically sealed after receiving the substrate; And an exhaust system that exhausts air and decompresses the inside of the chamber. According to the third aspect, first, the inside of the chamber is sealed as described above, so that unnecessary substances are prevented from entering the chamber. Further, if the pressure in the chamber is reduced by the exhaust system after the supply of the dry steam is stopped by the dry steam supply unit, the boiling point of the dry steam drops, so that the substrate can be dried more quickly.

In a fourth aspect based on any one of the first to third aspects, the cleaning liquid supply section includes a supply port at a lower portion of the processing tank, and supplies the cleaning liquid to the processing tank from the supply port. It is characterized by. According to the fourth aspect, since the supply port of the cleaning liquid supply unit is provided at the lower part of the processing tank, it is easy to secure a space at the upper part of the processing tank. This produces effects such as easy storage of the substrate in the processing bath.

In a fifth aspect based on the fourth aspect, the cleaning liquid supply section supplies the cleaning liquid from the supply port to the processing tank continuously for a predetermined time before the substrate is stored in the processing tank,
The cleaning liquid overflows from the upper part of the processing tank. Since the cleaning liquid supplied from the supply port of the cleaning liquid supply unit overflows from the upper part of the processing tank, unnecessary substances in the processing tank are removed to the outside together with the cleaning liquid. As described above, according to the sixth aspect, the inside of the processing tank can always be kept clean.

[0013]

FIG. 1 is a sectional view showing the structure of a substrate processing apparatus according to a first embodiment of the present invention. FIG.
FIG. 1 is a partially cutaway perspective view showing a configuration of a processing tank 1 housed in a decompression chamber 2. Hereinafter, the configuration of the substrate processing apparatus of the present embodiment will be described with reference to FIGS. In FIG. 1, a processing tank 1 is housed in a decompression chamber 2. Inside the processing tank 1, a plurality of (for example, 50) substrates W are arranged in parallel at predetermined intervals. The decompression chamber 2 is a processing tank 1
And a lid 22 attached to an upper portion of the main body 21. Lid 22 is attached to body 21
The lid 22 and the main body 21 are brought into close contact with each other by the action of the O-ring 23, and the inside of the decompression chamber 2 is closed. In the vicinity of the uppermost part inside the main body 21, IPA
Two (isopropyl alcohol) vapor and nitrogen gas inlet pipes 24 are attached. These two introduction pipes 24
Extends in the direction of arrangement of the substrates W accommodated in the processing tank 1 (that is, the direction perpendicular to the plane of the paper of FIG. 1), and IPA vapor and nitrogen A plurality of discharge ports (not shown) for discharging a gas and supplying the gas to the substrate W are provided. Further, both ends of the introduction pipe 24 penetrate the side surface of the main body 21 to be provided outside the IP.
It is connected to a source of A vapor (not shown).

Further, the present substrate processing apparatus is provided with an exhaust system 5 outside the decompression chamber 2, and the exhaust system 5 depressurizes the inside of the decompression chamber 2 as necessary. Further, the present substrate processing apparatus is provided with a control mechanism 6 for controlling the rate of lowering of the pure water level in a discharge / drying step described later. The control mechanism 6 will be described later in detail.

Next, referring to FIG. 1 and FIG.
Will be described in more detail. The outer wall of the processing tank 1 is defined by the outer plate 101 and has a substantially rectangular parallelepiped outer shape. In addition, the upper part of the processing tank 1 is open, and the bottom part is formed in an inverted roof shape whose central part protrudes downward.
The inverted roof-shaped ridge line 102 extends along the direction in which the substrates W are arranged. A receiving plate 103 is provided on the upper outer periphery of the outer plate 101 so as to surround the outer periphery. This receiving plate 103 cooperates with the upper peripheral edge of the outer plate 101,
An overflow groove 104 for receiving a liquid (pure water or chemical solution) overflowing from the processing tank 1 is formed. A hole is formed near the front end of the processing tank 1 and below the receiving plate 103, and one end of the overflow drain 105 is connected to this hole. The other end of the overflow drain 105 is
Although not shown, it is guided to the outside through the side surface of the main body 21 of the decompression chamber 2. That is, the pure water (or chemical solution) overflowing into the overflow groove 104 is discharged to the outside of the decompression chamber 2 through the overflow drain pipe 105.

An upflow pipe 106 is provided near the front end of the processing tank 1 and below the processing tank 1. Although not shown, one end of the upflow tube 106 is connected to the decompression chamber 2.
Is guided to the outside through the side surface of the main body 21, and is connected to a supply source of pure water and a chemical solution. Upflow tube 106
Is branched right and left at the front end of the processing tank 1, and the other end of the processing tank 1
Are connected to the infusion tube 107 provided on both left and right sides of the infusion tube. An outer injection tube 108 is provided so as to surround the outer periphery of the inner injection tube 107 at a predetermined interval. The left and right injection outer tubes 108 extend along the direction in which the substrates W are arranged, and connect the bottom of the processing bath 1 and the left and right sides. A plurality of holes 107a are formed on the outer periphery of the inner injection tube 107 at predetermined intervals along the axial direction. Each of the holes 107a is open in a direction opposite to the substrate W in the processing tank 1. A plurality of slits 108a are formed on the outer periphery of the outer injection tube 108 at predetermined intervals. Each slit 108a is open toward the direction of the substrate W in the processing bath. The slits 108a are arranged so as to be located between the substrates W. In addition,
The left and right inner pipes 107 and outer pipes 108 are terminated near the rear end of the processing tank 1.

On the left and right sides of the outer plate 101 and obliquely above the outer injection tube 108, a drainage tube 109 in the tank is provided. One end of the in-tank drain pipe 109 is connected to a hole 110 formed on the left and right sides of the outer plate 101. The left and right in-tank drain pipes 109 are integrated near the front end of the processing tank 1, and the other end is guided to the outside through a side surface of the main body 21 of the decompression chamber 2 (not shown). As a result, the liquid in the processing tank is discharged to the outside through the tank drain pipe 109.

As described above, the upflow pipe 10
6. Inner injection pipe 107, outer injection pipe 108 and drainage pipe 1 in tank
09 is provided at the lower part of the processing tank 1. Therefore, it is easy to secure a space above the processing tank 1. In the present substrate processing apparatus, a transfer robot 7 described later stores a plurality of substrates W in the processing tank 1 using this space.

Inside the processing tank 1, a pair of left and right substrate supporting portions 111 is fixedly provided. These substrate support portions 11
Both ends of 1 are fixed to a front end side surface portion and a rear end side surface portion of the inner wall of the outer plate 101. Each substrate support 111 includes:
A plurality of grooves are formed at predetermined intervals, and the substrate W
Is inserted, the substrate W is positioned and supported in the processing bath 1.

Further, a lifter 4 is provided in connection with the processing tank 1 as described above. The lifter 4 includes a substrate guide 4
1 and a lifting device 42 for raising and lowering the substrate guide 41
And a connecting plate 43 for connecting the lifting device 42 and the substrate guide 41. The substrate guide 41 has a plurality of grooves formed at the same pitch as the grooves formed in the substrate support portion 111, and the substrate W is supported by inserting the substrate W into the grooves.

Hereinafter, the operation state of the substrate processing apparatus having the above-described configuration will be described with reference to FIGS.

First, with reference to FIG. 3, a preparation process for substrate processing will be described. In the preparatory step, an upflow pipe 10 is supplied from a pure water supply source (not shown) outside the decompression chamber 2.
6 is supplied with pure water. The upflow pipe 106 guides the supplied pure water to the injection inner pipe 107. Injection tube 10
The pure water guided into the inside 7 flows out of each of the holes 107 a formed in the inner injection tube 107 into the outer injection tube 108. Pure water that has flowed into the outer injection tube 108 is
8 are ejected from the respective slits 108 a into the processing tank 1 and stored in the processing tank 1. Eventually, the pure water overflows from the upper part of the treatment tank 1 and the overflow groove 1
04 and overflow drain 10
The air is exhausted to the outside of the decompression chamber 2 through the pressure chamber 5. Therefore, unnecessary substances that are present in the processing tank 1 in advance are discharged to the outside of the decompression chamber 2 together with the pure water. by this,
The inside of the processing tank 1 is cleaned immediately before the substrate processing described below. After a certain period of time, the supply of pure water is reduced to the minimum necessary flow rate that can keep the inside of the processing tank 1 clean. Thus, the preparation process for the substrate processing is completed.

Next, the substrate transfer / loading step will be described with reference to FIG. In the substrate transfer / loading step, a small amount of nitrogen gas or other inert gas is introduced into the decompression chamber 2, whereby the inside of the chamber 2 is purged. In addition, the supply of pure water is changed from the above-described necessary minimum flow rate to a flow rate necessary for processing. In such a situation, the transfer robot 7
Holds a plurality of substrates W having undergone other processes by the chuck 71 and transports the substrates W to an upper portion of the substrate processing apparatus. At this time, the lid 22 of the decompression chamber 2 is open (not shown), and the substrate guide 41 is lifted up to the top of the decompression chamber 2 by the lifting device 42. Next, the transfer robot 7 places the substrate W on the substrate guide 41, rotates the chuck 71 in the direction of arrow A, and releases the substrate W. Thus, the substrate W is supported by the substrate guide 41. Next, the lifter 4 lowers the substrate guide 41 by the elevating device 42 as shown by the arrow B. When the substrate guide 41 descends below the fixed position of the substrate support 111 inside the processing tank 1, the substrate W is transferred from the substrate guide 41 to the substrate support 111, and the substrate W is transferred by the substrate support 111. It is positioned and supported. Thus, each substrate W is stored in the processing tank 1. Thereafter, the lid 22 is automatically put on the main body 21. At this time, the operation of the O-ring 23 seals the decompression chamber 2 (see FIG. 1 and the like).

Next, referring to FIG. 5, the chemical solution treatment step will be described. During this chemical solution treatment step, a predetermined amount of nitrogen gas is introduced into the decompression chamber 2 from the introduction pipe 24, whereby the inside of the chamber 2 is purged. Under such circumstances, the pure water flowing from the chemical supply source (not shown) outside the decompression chamber 2 to the upflow pipe 106 (see FIG. 2) is mixed with a chemical (eg, an etching liquid).
Is supplied. The upflow pipe 106 guides the supplied chemical solution to the inner injection pipe 107. The chemical solution guided into the injection inner tube 107 is filled in each hole 10 formed in the injection inner tube 107.
7a, flows out into the outer injection tube 108, and further jets into the processing tank 1 through each slit 108a formed in the outer injection tube 108. Since a chemical solution is continuously supplied to the upflow pipe 106 from an external chemical solution supply source for a certain period of time, the concentration of the chemical solution in the processing tank 1 gradually increases, and eventually becomes constant. During that time, the overflowing chemical flows into the overflow groove 104 and is discharged to the outside of the decompression chamber 2 through the overflow drain pipe 105. Thus, the substrate W is always immersed in a new chemical solution. Then, when a certain period of time has elapsed from the start of the chemical liquid processing step, the chemical liquid supply source stops supplying the chemical liquid, and the chemical liquid processing step (for example, etching processing) ends.

Next, the cleaning step will be described with reference to FIG. In the cleaning step, pure water is supplied to the upflow pipe 106 from a pure water supply source (not shown) outside the decompression chamber 2. The upflow pipe 106 guides the supplied pure water to the injection inner pipe 107. The pure water guided into the inner injection tube 107 flows out of each of the holes 107 a formed in the inner injection tube 107 into the outer injection tube 108. The pure water that has flowed into the outer injection tube 108 is jetted into the processing tank 1 from each slit 108 a formed in the outer injection tube 108. Here, since each slit 108a is arranged so as to be located between the substrates W arranged in the processing tank, pure water spouted from each slit 108a is
, And the surface of each substrate W is evenly cleaned. In addition, the liquid overflowing from the upper part of the processing tank 1 due to the supply of pure water is supplied to the overflow groove 1.
04, and is discharged out of the decompression chamber 2 via the overflow drain 105. At this time, the chemical solution in which each substrate W has been immersed in the processing tank 1 does not stay in the pure water but is discharged to the outside together with the overflow water. Since pure water is continuously supplied to the up-flow pipe 106 from an external pure water supply source, the concentration of the chemical solution in the treatment tank gradually decreases, and the inside of the treatment tank 1 is replaced with pure water only. .
When a resistivity meter (not shown) detects that the resistivity of the liquid in the processing tank 1 has reached a predetermined value (preferably the resistivity of pure water), the supply of pure water is stopped, The cleaning process ends. In this embodiment, pure water is used for cleaning the substrate. However, the present invention is not limited to this, and other cleaning liquids (for example, hydrofluoric acid-added pure water) having a property capable of cleaning the substrate are used. May be used.

Next, the drainage / drying step will be described with reference to FIGS. After the completion of the washing step, pure water is sufficiently stored in the processing tank 1. Therefore, in the drainage / drying step, first, a very small amount of pure water is discharged from the drain pipe 109 in the tank in order to lower the level of the pure water by a very small amount. This is to prevent IPA condensed on the liquid surface of the pure water by IPA vapor supply from flowing out of the processing tank 1. After the level of the pure water is reduced by a very small amount as described above, IPA vapor is supplied to the introduction pipe 24 from an external IPA supply source (not shown). As shown in FIG. 6, the introduction pipe 24 ejects the supplied IPA vapor toward the surface of the pure water stored in the processing tank 1. As a result, the IPA vapor condenses on the pure water level in the processing tank 1.

After a lapse of a certain time (after the condensed IPA layer has a certain thickness), the control mechanism 6 opens the quick release valve 66 by a predetermined amount, and controls the descending speed described later with reference to FIG. While executing, the pure water in the processing tank 1 is discharged from the tank drain pipe 109. Throughout this discharge, the inlet tube 24 continues to supply IPA vapor. As the level of pure water drops due to this discharge, IPA condensed on the pure water level adheres to each substrate W. As a result, each substrate W
The droplets adhering on the surface of the are replaced by condensed IPA. Thereby, each substrate W is sufficiently dried without leaving a droplet on the surface of each substrate W. And FIG.
When the pure water level is sufficiently lowered and the pure water remaining between each substrate W and the substrate supporting portion 111 is sufficiently dried as shown in (2), the supply of the IPA vapor is stopped. In this embodiment, IPA is used to dry the substrate. However, the present invention is not limited to this. IPA may be used as long as it is water-soluble and has a property of reducing the surface tension of water droplets remaining on the substrate. Steam of another organic solvent may be used instead of steam.

After stopping the supply of the IPA vapor, the pressure reducing chamber 2
The inside is purged with a predetermined amount of nitrogen gas. At the same time, the pressure in the decompression chamber 2 is reduced by the exhaust system 5 (see FIG. 1). As a result, the boiling point of the IPA decreases, so that the IPA remaining in the decompression chamber 2 evaporates easily, and the surface of each substrate W dries in a short time. After a certain period of time (after unnecessary IPA in the decompression chamber 2 is dried by decompression), the exhaust system 5 (see FIG. 1) is stopped and the decompression is terminated. After this pressure reduction, purging with nitrogen gas is performed again to return the inside of the pressure reduction chamber 2 to the atmospheric pressure. Thus, the drain / drying step is completed. As explained above,
The present substrate processing apparatus can perform reduced-pressure drying by the reduced-pressure chamber 2 and the exhaust system 5, and thereby can generate a high-quality substrate W.

Next, the substrate unloading / transporting step will be described with reference to FIGS. First, as shown in FIG. 8, the lid 22 of the decompression chamber 2 is opened with respect to the main body 21, and the substrate guide 41 is raised by the lifter 4. Next, as shown in FIG. 9, when the substrate guide 41 moves up to the upper position of the decompression chamber 2, the transfer robot 7 holds the substrate W by the chuck 71 and transfers the substrate W to another position. After this transfer, the lid 22 is closed, and purging with nitrogen gas is performed in the decompression chamber 2.

If the diameter of the orifice of the quick release valve 66 is constant, the flow rate of the pure water passing through the orifice in the drainage / drying step depends on the potential energy of the pure water stored in the processing tank 1. That is, it is proportional to the height of the pure water level. Therefore, when the liquid level of the pure water becomes lower, the flow rate of the pure water discharged from the quick release valve 66 decreases,
As a result, the descending speed decreases. Such a change in the descending speed causes unevenness in the processing of the substrate surface. This uneven processing causes a processing failure in substrate processing requiring strict processing accuracy. Therefore, the above drainage /
In the drying step, the control mechanism 6 executes the control of the first descending speed as described below with reference to FIG.
In FIG. 10, a liquid level sensor 61 is provided inside the processing tank 1.
(Not shown in FIGS. 3 to 9). A small amount of an inert gas such as nitrogen is supplied to the liquid level sensor 61 via a micro pressure gauge 62. In response to the supply of nitrogen or the like, the nitrogen bubbles are discharged from the tip of the liquid level sensor 61. The liquid level sensor 61 is covered with a hollow columnar cover so that the air bubbles do not adversely affect the substrate W. The micro pressure gauge 62 measures the current position of the liquid level of the pure water in the processing tank 1 based on the discharge pressure of the bubbles from the liquid level sensor 61. The liquid surface position measured by the micro pressure gauge 62 is a height with respect to a predetermined reference position. The measurement result of the micro pressure gauge 62 is given to the arithmetic circuit 63.

The orifice diameter is set in advance in the storage device of the arithmetic unit 63 for each liquid level of pure water. More specifically, the orifice diameter is set so as to increase as the liquid level of the pure water is lowered, and to make the flow rate of the pure water discharged from the quick-open valve 66 constant. Is selected such that the descent speed of the cruiser is constant. Arithmetic circuit 63
Calculates the orifice diameter corresponding to the current position of the liquid surface, given the current position of the liquid surface by the micro pressure gauge 62. That is, when the current position of the liquid surface indicates a relatively high position, the arithmetic circuit 63 calculates a relatively narrow orifice diameter. When the current position of the liquid surface indicates a relatively low position, the arithmetic circuit 63 calculates a relatively wide orifice diameter.

The electropneumatic regulator 64 receives the calculation result (orifice diameter) of the calculation circuit 63 and determines the pilot air pressure based on the orifice diameter. The pressure regulator (actuator) 65 adjusts the opening degree (orifice diameter) of the quick release valve 66 based on the pilot air pressure to control the flow rate of pure water discharged from the tank drain pipe 109. Accordingly, the pressure regulator 65 relatively widens the opening degree of the quick release valve 66 so as to keep the falling rate of the pure water level falling from the upper part of the processing tank 1 in the drainage / drying step constant. To go. As a result, the falling speed of the pure water liquid level becomes constant, and processing unevenness due to the change in the falling speed does not occur on the substrate surface, so that a high-quality substrate W is generated.

There are various types of drainage / drying steps, including a drainage / drying step which does not require relatively high processing accuracy. Hereinafter, in such a drainage / drying process, the control mechanism 6 executes the following control of the second descending speed. FIG. 10 is also referred to in the control of the second descending speed, so that the following description is partially simplified.

In the storage device of the arithmetic circuit 63, a predetermined threshold value and a high-speed and a low-speed lowering speed of the pure water level (described later) are set in advance. This threshold is selected so as to indicate a predetermined liquid level position, and more specifically, is selected so as to indicate at least a position above the substrate support 111 in the processing bath 1. The arithmetic circuit 63 calculates a relatively high descent speed when the current position of the liquid level given by the micro pressure gauge 62 indicates a position higher than the threshold,
If it indicates a low position, a relatively low descent speed is calculated. Here, the high speed of the pure water liquid drop is
At the same time when the liquid level of the pure water descending in the processing tank 1 passes through each substrate W, the liquid droplets on the surface of each substrate W are condensed.
It is a speed that can be replaced by PA. Further, the low speed of the pure water liquid level lowering means that each pure water descending in the processing tank 1 passes through the substrate support 111, and then each substrate W and the substrate support 1
The speed is such that no droplets remain between them.

The electropneumatic regulator 64 receives the operation result (down speed) of the operation circuit 63 and determines the pilot air pressure based on the down speed. The pressure regulator (actuator) 65 adjusts the opening degree (orifice diameter) of the quick release valve 66 based on the pilot air pressure to control the flow rate of pure water discharged from the tank drain pipe 109.
Accordingly, the pressure regulator 65 obtains the high-speed pure water liquid descending speed until the pure water liquid surface falling from the upper part of the processing tank 1 reaches the threshold portion in the drainage / drying process. The opening degree of the quick release valve 66 is relatively increased.
Thereby, the speed of the substrate processing by the present substrate processing apparatus can be increased. Conversely, after the liquid level position of the pure water reaches the threshold portion, the pressure regulator 65 relatively reduces the opening of the quick release valve 66 so as to obtain the above-described low descending speed. As described above, since each substrate W is inserted and supported in the groove of each substrate support portion 111, it is easy to form a complicated shape such as a small gap (see FIG. 2). Therefore, when the pure water liquid surface is dropped at a high speed, the pure water in the supporting portion of the substrate W is separated from the liquid surface, and the liquid droplet is likely to remain on the supporting portion. However, when the level of pure water is lowered at a low speed as described above,
Since the pure water in the support portion can be taken into the liquid surface by the surface tension of the liquid surface, and further, the support portion is exposed to IPA vapor condensed on the liquid surface for a long time. Droplets are less likely to remain in the portion. Thereby, the present substrate processing apparatus can sufficiently dry each substrate W over the entire surface thereof, and a high-quality substrate W is generated.

As described above, since the control mechanism 6 directly measures the pure water level in the draining / drying process without indirectly measuring it, it accurately controls the pure water level drop speed. It has the effect of being able to. The control mechanism 6 includes:
In addition to the control described above, control may be performed to change the liquid level lowering speed according to the quality of the film formed on the surface of each substrate W.

FIG. 11 is a sectional view showing the structure of a substrate processing apparatus according to the second embodiment of the present invention. Note that the substrate processing apparatus according to the present embodiment is significantly different from the first embodiment in that the processing bath is housed in an open chamber. However, since there are many portions common to both, the portions corresponding to the configuration shown in FIG. 1 in the substrate processing apparatus shown in FIG. 11 are given the same reference numerals.

In FIG. 11, the processing tank 1 is housed in an open chamber 8. Since the processing tank 1 is configured in the same manner as that shown in FIG. 2, it is pointed out in advance that FIG. 2 will be referred to when describing the processing tank 1.
The open chamber 8 includes a main body 81 that houses the processing bath 1 and a lid 82 that is attached to an upper part of the main body 81. The lid 82 is configured to be openable and closable with respect to the main body 81, but when the lid 82 is closed, the inside of the open chamber 8 is not as sealed as the decompression chamber 2 (see FIG. 1 and the like). In the vicinity of the uppermost portion inside the main body 81, two inlet pipes 24 for IPA vapor or the like are attached similarly to the first embodiment.
1, and is connected to a supply source (not shown) of IPA vapor or the like provided outside. Furthermore, the main body 8
Two exhaust ports 83 for IPA vapor or the like are provided in the vicinity of the outermost uppermost portion.

Further, in the present substrate processing apparatus, a damper 84 is provided outside the main body 81.
Exhausts the gas inside the main body 81 as necessary. Further, the present substrate processing apparatus is provided with a control mechanism 6 similar to that of the first embodiment.

Hereinafter, the operation state of the substrate processing apparatus having the above configuration will be described with reference to FIGS. The following steps are the same as those described with reference to FIGS. 3 to 10 in the first embodiment, and therefore, the description thereof will be simplified.

First, with reference to FIG. 12, a preparation process for substrate processing will be described. In the preparation process, the open chamber 8
From an external pure water supply source (not shown)
06 is supplied with pure water. The supplied pure water follows the path described with reference to FIG. 3 in the processing tank 1 and is stored in the processing tank 1. Eventually, the pure water overflows from the upper part of the processing tank 1, follows the path described with reference to FIG. 3, and is discharged to the outside of the open chamber 8. After a lapse of a predetermined time, the supply of pure water is performed in the treatment tank 1.
The flow rate is reduced to the minimum necessary to keep the inside clean. Thus, the preparation process for the substrate processing is completed.

Next, with reference to FIG. 13, the substrate transfer / loading step will be described. During the substrate transfer / loading process, a small amount of nitrogen gas or other inert gas is introduced into the open chamber 8, whereby the inside of the chamber 8 is purged. In addition, the supply of pure water is changed from the above-described necessary minimum flow rate to a flow rate necessary for processing. Further, the damper 84 is closed, but the gas in the open chamber 8 is exhausted to the outside by the two exhaust ports 83. Transfer robot 7 and lifting device 42
Performs the same operation as the operation described with reference to FIG. 3, and as a result, each substrate W is stored in the processing tank 1. Thereafter, the lid 82 is automatically put on the main body 81. (Figure 1
2). Thus, the substrate transfer / loading process is completed.

Next, the chemical treatment step will be described with reference to FIG. During this chemical treatment step, a predetermined amount of nitrogen gas is introduced into the open chamber 8, whereby the inside of the chamber 8 is purged. Further, the damper 84 is opened, and the gas in the open chamber 8 is forcibly discharged to the outside. Under such circumstances, the chemical is supplied to the pure water flowing from the chemical supply source (not shown) outside the open chamber 8 to the upflow pipe 106 (see FIG. 2). The supplied chemical solution is treated in the treatment tank 1 by
Following the path described with reference to FIG. The chemical liquid overflows from the upper part of the processing tank 1, follows the path described with reference to FIG. 5, and is discharged to the outside of the open chamber 8. As a result, each substrate W is always immersed in a new chemical solution. Then, when a certain period of time has elapsed from the start of the chemical processing step, the chemical supply source stops supplying the chemical, and the chemical processing step ends.

Next, the cleaning step will be described with reference to FIG. During this cleaning step, a predetermined amount of nitrogen gas is introduced into the open chamber 8, whereby the inside of the chamber 8 is purged. Further, the damper 84 is opened, and the gas in the open chamber 8 is forcibly discharged to the outside. Under such circumstances, the cleaning process is started. Pure water is supplied to the upflow pipe 106 from a pure water supply source (not shown) outside the open chamber 8. The supplied pure water is supplied to the processing tank 1 in FIG.
Along the route described with reference to FIG. The chemical liquid overflows from the upper part of the processing tank 1, follows the path described with reference to FIG. 5, and is discharged to the outside of the open chamber 8. As a result, the surface of each substrate W is evenly washed, and the chemical solution that has immersed each substrate W in the processing tank 1 is discharged to the outside together with overflow water without staying in pure water. When a resistivity meter (not shown) detects that the resistivity of the liquid in the processing tank 1 has reached a predetermined value (preferably the resistivity of pure water), the supply of pure water is stopped, The cleaning process ends.

The above-described chemical solution supply step and cleaning step are repeatedly performed on the substrate W as many times as necessary.

Next, the drainage / drying process will be described with reference to FIGS. During this draining / drying process, the damper 84 is closed, but the gas (IPA vapor) in the open chamber 8 is exhausted to the outside by the two exhaust ports 83. Thereafter, the drainage / drying step is started. First, a very small amount of pure water in the processing tank 1 is discharged from the drain pipe 109 in the tank, whereby the IPA layer condensed on the pure water surface by the IPA vapor jet flows out of the processing tank 1. To prevent After discharging a very small amount of pure water, the introduction pipe 24
Is the IP outside the open chamber 8 as shown in FIG.
The IPA vapor supplied from the A supply source (not shown) is jetted toward the liquid surface of pure water stored in the processing tank 1. As a result, IPA is condensed on the pure water level in the processing tank 1.

After a lapse of a predetermined time, the control mechanism 6 opens the quick release valve 66 by a predetermined amount, and controls the first or second descent speed described above with reference to FIG. The pure water is discharged from the drainage pipe 109 in the tank. Note that the control of the first or second descent speed is the same as that of the first embodiment, and the description thereof will be omitted in the second embodiment. Throughout this discharge, the inlet tube 24 continues to supply IPA vapor. As the level of the pure water drops due to this discharge, the IPA layer condensed on the pure water level adheres to each substrate W. As a result, the droplets adhering to the surface of each substrate W Is replaced by the condensed IPA layer. Thereby, each substrate W is sufficiently dried without leaving a droplet on the surface of each substrate W. Then, as shown in FIG. 7, when the pure water level is sufficiently reduced and the pure water remaining between each substrate W and the substrate support 111 is sufficiently dried, the supply of the IPA vapor is stopped. Is done.

After the supply of IPA vapor is stopped, the open chamber 8
The inside is purged with a predetermined amount of nitrogen gas. as a result,
The IPA that has been replaced with pure water on the surface of each substrate W surely evaporates, and the surface of each substrate W dries in a short time. After a certain period of time (after unnecessarily condensed IPA is dried with nitrogen gas), the drainage / drying step is completed, the amount of nitrogen gas is changed to a minute amount, purging is continued, and the next substrate is removed. Move on to unloading / transportation process.

Next, the substrate unloading / transporting step will be described with reference to FIGS. First, as shown in FIG. 17, the lid 82 of the open chamber 8 opens with respect to the main body 81, and the substrate guide 41 is raised by the lifter 4. Next, as shown in FIG. 9, when the substrate guide 41 moves up to the upper position of the open chamber 8, the transfer robot 7 holds the substrate W by the chuck 71 and transfers the substrate W to another position. After this transfer, the lid 82 is closed,
Purging of the inert gas is performed to remove unnecessary substances such as condensed IPA that may remain inside the open chamber 8.

As described above, according to the substrate processing apparatus of the second embodiment, in the drain / drying step, the control mechanism 6 directly measures the pure water level without performing indirect measurement. Therefore, there is an effect that the descending speed of the liquid level can be accurately controlled. The control mechanism 6 may perform control to change the liquid level lowering speed in accordance with the quality of the film formed on the surface of each substrate W in addition to the above control. Further, the substrate processing apparatus according to the second embodiment does not have a configuration in which drying under reduced pressure is not possible, so that the manufacturing cost of the apparatus itself can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a substrate processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a partially broken perspective view showing a configuration of a processing tank 1 housed in a decompression chamber 2.

FIG. 3 is a view for explaining a preparation process of a substrate processing performed by the substrate processing apparatus shown in FIG. 1;

FIG. 4 is a view for explaining a substrate transport / loading step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 5 is a view for explaining a chemical solution processing step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 6 is a view for explaining a drainage / drying step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 7 is a view for explaining a drainage / drying step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 8 is a view for explaining a substrate unloading / transporting step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 9 is a view for explaining a substrate unloading / transporting step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 10 is a diagram for explaining control of a descending speed executed by the control mechanism 6 shown in FIG. 1 in the drainage / drying step.

FIG. 11 is a sectional view illustrating a configuration of a substrate processing apparatus according to a second embodiment of the present invention.

FIG. 12 is a view for explaining a preparation process of a substrate processing performed by the substrate processing apparatus shown in FIG. 11;

FIG. 13 is a view for explaining a substrate transport / loading step performed by the substrate processing apparatus shown in FIG. 11;

FIG. 14 is a view for explaining a chemical solution processing step performed by the substrate processing apparatus shown in FIG. 11;

FIG. 15 shows a drainage / water discharge executed by the substrate processing apparatus shown in FIG. 11;
It is a figure for explaining a drying process.

FIG. 16 shows a drainage / water discharge performed by the substrate processing apparatus shown in FIG. 11;
It is a figure for explaining a drying process.

FIG. 17 is a view for explaining a substrate unloading / transporting step performed by the substrate processing apparatus shown in FIG. 11;

FIG. 18 is a view illustrating a substrate unloading / transporting step performed by the substrate processing apparatus shown in FIG. 1;

FIG. 19 is a view for explaining a configuration of a conventional substrate processing apparatus and a drainage / drying process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Treatment tank 2 ... Decompression chamber 24 ... Introduction pipe 5 ... Exhaust system 6 ... Control mechanism 61 ... Liquid level sensor 62 ... Micro pressure gauge 63 ... Operation circuit 64 ... Electro-pneumatic regulator 65 ... Pressure regulator 66 ... Quick release valve 7 ... Open chamber W… Substrate

Claims (5)

[Claims] 1. A substrate processing apparatus for immersing a substrate contained in a processing bath in a cleaning liquid, cleaning the substrate, and then drying the substrate, wherein a cleaning liquid is supplied to the processing bath, A cleaning liquid supply unit for immersing the substrate stored in the cleaning liquid into the cleaning liquid, and discharging the cleaning liquid stored in the processing tank to the outside;
A discharge unit for lowering the liquid level of the cleaning liquid in the processing tank; and a dry steam supply unit for supplying a dry vapor for drying the substrate to a liquid level of the cleaning liquid lowered by the discharge unit; A detection unit that is provided in the processing tank and detects a current position of the liquid level descending in the processing tank; and the discharge unit discharges based on a current position of the liquid surface detected by the detection unit. A substrate processing apparatus comprising: a controller configured to control a flow rate of the cleaning liquid. 2. A support section for supporting the substrate in the processing tank and accommodating the substrate at a predetermined position in the processing tank, wherein the control section controls a position of the substrate in the support section. It has in advance a threshold set in relation to the support portion, and when it is determined that the current position of the liquid level detected by the detection unit has reached the threshold, the discharge unit discharges 2. The substrate processing apparatus according to claim 1, wherein the flow rate of the cleaning liquid is controlled to be relatively small, and a descending speed of the liquid level in the processing tank is reduced. 3. A processing chamber containing the processing tank, the processing tank storing the substrate therein, and a chamber hermetically sealed after the processing chamber stores the substrate; and evacuation of gas in the hermetically sealed chamber, thereby depressurizing the chamber. The substrate processing apparatus according to claim 1, further comprising an exhaust system configured to perform the processing. 4. The cleaning liquid supply unit according to claim 1, wherein a supply port is provided at a lower portion of the processing tank, and the cleaning liquid is supplied to the processing tank from the supply port. A substrate processing apparatus according to any one of the above. 5. The cleaning liquid supply section supplies the cleaning liquid from the supply port to the processing tank continuously for a predetermined time before the substrate is stored in the processing tank. The substrate processing apparatus according to claim 4, wherein the substrate overflows from an upper portion of the substrate.