JP3626360B2 - Substrate processing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention supplies a treatment liquid for treating a plurality of semiconductor substrates, glass substrates for liquid crystal display devices, glass substrates for photomasks, optical disk substrates, etc. (hereinafter simply referred to as “substrates”) to a treatment tank to obtain a predetermined amount. The present invention relates to a substrate processing apparatus and method for performing a series of processes by repeatedly storing and discharging the stored processing liquid from the processing tank.
[0002]
[Prior art]
Conventionally, a surface treatment such as etching with a chemical solution or cleaning with pure water is sequentially performed on the substrate in a treatment tank in a substrate treatment apparatus, thereby achieving a series of treatments. In many cases, a chemical solution used for the surface treatment is used by mixing a plurality of types of base solutions (hereinafter referred to as stock solutions) such as ammonia water and hydrogen peroxide solution.
[0003]
These stock solutions are preliminarily weighed in a weighing tank before being put into a chemical tank that stores the chemical and performs substrate processing. This is because the mixing ratio of the chemical solution in the chemical solution tank will be non-uniform unless the stock solution is accurately weighed, resulting in non-uniform surface treatment of the substrate.
[0004]
Various methods have been applied as methods for weighing the stock solution in the weighing tank. As an example, a nitrogen tube is placed in the weighing tank and the pressure in the tube is measured to detect the liquid volume. There is a so-called bubble blowing type liquid level detection method. That is, when nitrogen gas is continuously discharged from the tip of the tube immersed in the liquid in the weighing tank, the pressure in the tube is proportional to the distance from the tube tip to the liquid level (that is, the liquid depth). Therefore, by measuring the pressure in the tube with a pressure sensor using a semiconductor pressure element, the liquid level in the weighing tank can be detected, and the liquid amount can also be detected.
[0005]
[Problems to be solved by the invention]
However, a semiconductor pressure element used as a pressure sensor may cause a malfunction due to a drift phenomenon based on long-time use. FIG. 6 is a diagram showing an error due to drift of the semiconductor pressure element. As shown in the figure, an error occurs in the output of the semiconductor pressure element after a long time use of several thousand hours, and the error tends to increase with time.
[0006]
In general, the substrate processing apparatus is operated continuously for a long period of time. Accordingly, the pressure sensor malfunctions with continuous operation of the substrate processing apparatus for a long period of time, which makes accurate weighing in the weighing tank difficult, and the mixing ratio of the chemicals in the chemical tank becomes uneven. is there.
[0007]
A problem similar to this may occur also in a liquid storage tank (for example, a chemical tank) other than the weighing tank in the substrate processing apparatus. Further, even when a liquid level detection method (for example, an ultrasonic measurement method) other than the method of measuring the pressure in the tube for supplying nitrogen using a semiconductor pressure element is applied, the same as FIG. Due to the drift phenomenon, malfunction may occur.
[0008]
The present invention has been made in view of the above problems, and provides a substrate processing apparatus and method capable of detecting the amount of liquid in a tank with high accuracy even when continuously operating for a long time. Objective.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 is to supply a processing solution for processing a substrate to a tank and store a predetermined amount, and to discharge the processing liquid stored in the predetermined amount from the tank. A substrate processing apparatus that repeatedly performs a series of processing, wherein (a) a liquid amount detection unit that detects a liquid amount stored in the tank, and (b) zero correction is performed on the liquid amount detection unit. And a control means for controlling the liquid amount detecting means, and after the processing liquid is discharged from the tank during the series of processing, the control means is supplied with a new processing liquid. In the meantime, the liquid amount detecting means performs zero point correction every time the inside of the tank becomes empty .
[0010]
The invention of claim 2 is a series of repetition of a supplying step of supplying a processing solution for processing a substrate to a tank and storing a predetermined amount and a discharging step of discharging the processing solution stored in the predetermined amount from the tank. A substrate processing method for performing the above-described processing, wherein after the discharge step is completed, before the shift to a new supply step, the zero point correction of the liquid amount detection means for detecting the liquid amount stored in the tank is performed in the tank. A correction process is performed every time the interior of the is empty .
The invention of claim 3 is a series of processing by repeatedly supplying a processing solution for processing a substrate to a tank and storing a predetermined amount, and discharging the processing liquid stored in the predetermined amount from the tank. A substrate surface processing apparatus for measuring the pressure of the processing liquid by measuring the atmospheric pressure when gas is released from a tube whose tip is submerged in the processing liquid stored in the tank. A level sensor, and a control unit that transmits a reset signal to the liquid level sensor to execute zero point correction, and the control unit has discharged the processing liquid from the tank during the series of processing. Thereafter, the liquid level sensor is caused to execute zero point correction until a new treatment liquid is supplied to the tank.
[0011]
In the present specification, “treatment liquid” is a general term for liquids used for substrate processing, and includes a stock solution such as ammonia water, a chemical solution obtained by mixing the stock solution, and pure water. The term “tank” includes a chemical tank, a water washing tank, and a weighing tank.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
<1. Overall schematic configuration of substrate processing apparatus>
First, the overall configuration of the substrate processing apparatus according to the present invention will be described. FIG. 1 is a schematic front view showing an example of the overall configuration of a substrate processing apparatus according to the present invention. The substrate processing apparatus 100 includes chemical baths CB1 and CB2, washing baths WB1, WB2, and FR, a drying unit SD, and a substrate transport robot TR that transports a substrate. In addition, the substrate processing apparatus 100 has, at both ends thereof, a loader unit LD for mounting a cassette C storing unprocessed substrates W and an unloader unit ULD for mounting a cassette C storing processed substrates W. I have.
[0014]
The chemical tanks CB1 and CB2 are treatment tanks that can store chemical liquids such as sulfuric acid, ammonia, hydrochloric acid, hydrofluoric acid, hydrogen peroxide water, or a mixture thereof. The washing tanks WB1 and WB2 are treatment tanks that store pure water and wash the chemical solution attached to the substrate W. The washing tank FR is also a washing treatment tank that contains pure water, but is mainly used for finishing washing. Further, the drying unit SD is a processing unit that removes and dries water droplets attached to the substrate W while rotating the substrate W.
[0015]
The substrate transfer robot TR is movable in the horizontal direction and the vertical direction, dispenses an unprocessed substrate group (lot) from the loader unit LD, and circulates and transfers the lot between the processing tanks according to a predetermined processing procedure. At the same time, the robot passes the processed lot to the unloader unit ULD. The substrate transport robot TR includes a pair of hands 11 that can be freely opened and closed. The hand 11 is provided with a plurality of grooves for holding the substrate W in parallel at a constant pitch (not shown). ), The lot is held by the plurality of grooves. When the substrate transport robot TR receives a lot from the loader unit LD, the pair of hands 11 of the substrate transport robot TR grips the lot lifted from the cassette C by a holder (not shown) provided below the cassette C. Is done by doing. Also, when a lot is delivered to the unloader unit ULD, contrary to the above, the lot is delivered from the hand 11 to a holder (not shown), and the lot is stored in the cassette C by lowering the holder. The The example shown here is an apparatus in which a lot is taken out from the cassette C, and the lot is directly held and transported by the substrate transfer robot TR. It may be a so-called cassette conveyance type apparatus.
[0016]
<2. Schematic configuration of treatment tank>
Next, a schematic configuration of the processing tank included in the substrate processing apparatus 100 will be described. Here, the structure of chemical | medical solution tank CB1 is demonstrated as an example of a processing tank. FIG. 2 is a diagram showing a schematic configuration of the chemical tank CB1.
[0017]
The chemical bath CB1 stores a chemical solution (so-called SC-1 solution) obtained by mixing ammonia water (NH ₄ OH), hydrogen peroxide water (H ₂ O ₂ ), and pure water (H ₂ O) in a predetermined amount, It is a treatment tank that performs surface treatment by immersing the substrate in the liquid. The chemical tank CB1 includes three weighing tanks 30, 40, and 50 in addition to the immersion tank 20 and the collection tank 25.
[0018]
The immersion tank 20 is a tank for storing the mixed liquid and immersing the substrate. Recovery tank 25 is a tank for collecting the immersion tank 2 0 or al overflowing chemicals. The chemical liquid overflowing into the collection tank 25 is circulated to the immersion tank 20 by the circulation pump 26 and purified by the circulation filter 27 in the path. Moreover, the chemical | medical solution stored in the immersion tank 20 can be discharged | emitted out of a tank by opening the discharge valve 28. FIG.
[0019]
The three weighing tanks 30, 40, and 50 are tanks for weighing ammonia water, hydrogen peroxide water, and pure water in predetermined liquid amounts, respectively, and putting them in the immersion tank 20. Ammonia water can be supplied to the weighing tank 30 by opening the supply valve 31, and from the weighing tank 30, the weighed ammonia water is charged into the immersion tank 20 by opening the charging valve 32. Can do. Similarly, the hydrogen peroxide solution can be supplied to the weighing tank 40 by opening the supply valve 41, and the hydrogen peroxide that has been weighed in the immersion tank 20 by opening the charging valve 42 from the weighing tank 40. Water can be added. Further, similarly, pure water can be supplied to the weighing tank 50 by opening the supply valve 51, and pure water that has been weighed is supplied to the immersion tank 20 from the weighing tank 50 by opening the charging valve 52. can do. The configuration and processing mode of the weighing tank will be further described later.
[0020]
<3. Configuration and processing mode of weighing tank>
In the chemical bath CB1, the stock solution (in this case, ammonia water, hydrogen peroxide solution, pure water) is not charged directly into the immersion bath 20, but each is weighed by the weighing baths 30, 40, 50 and then put into the immersion bath 20. The reason is that it is necessary to make the mixing ratio of the chemical solution in the immersion bath 20 constant so that the surface treatment of the substrate is uniformly performed. Therefore, it is desired that each weighing in the weighing tanks 30, 40, 50 be performed as accurately as possible. For this reason, each of the weighing tanks 30, 40, 50 is provided with a liquid level meter as a liquid amount detecting means for accurately detecting the amount of liquid stored in each weighing tank.
[0021]
FIG. 3 is a diagram showing a main configuration of the weighing tank 30. A liquid level meter 35 and a tube 36 are attached to the weighing tank 30. The tube 36 is a cylindrical tube with an open end, and is attached to the weighing tank 30 so that the longitudinal direction thereof coincides with the vertical direction and the tip end sinks in the liquid. The other end of the tube 36 is connected to a nitrogen supply source (not shown), and the nitrogen supplied from the nitrogen supply source passes through the tube 36 and is released from the tip of the tube 36. At this time, if ammonia water is stored in the weighing tank 30, the pressure in the tube 36 is equal to the pressure received by the tip of the tube 36 from the ammonia water, and from the tip to the liquid level of the ammonia water. The value is proportional to the distance.
[0022]
The liquid level meter 35 is a level sensor using a semiconductor pressure element. The liquid level meter 35 is connected to a part of the tube 36 and can measure the atmospheric pressure in the tube 36. When the ammonia water is stored in the weighing tank 30, the liquid level meter 35 detects the liquid level of the ammonia water by measuring the atmospheric pressure in the tube 36, and is stored in the weighing tank 30. The amount of liquid that is present can be detected.
[0023]
The substrate processing apparatus 100 includes a control unit 60 configured using a computer, and the control unit 60 is electrically connected to the supply valve 31, the input valve 32, and the liquid level meter 35. That is, the control unit 60 grasps the amount of liquid stored in the weighing tank 30 based on the signal from the liquid level meter 35, and controls the opening and closing of the supply valve 31 and the input valve 32 according to the amount of liquid. -ing
[0024]
The above description is about the weighing tank 30, but the weighing tank 40 and the weighing tank 50 have the same configuration as that in FIG. 3, and the control unit 60 supplies the liquid amount and supply of the weighing tanks 40 and 50.・ Managing inputs. Further, the immersion tank 20 and the collection tank 25 shown in FIG. 2 are also provided with the same liquid level gauge 35 and tube 36 (not shown), and the control unit 60 has the immersion tank 20 and the collection tank 25. The amount and discharge of liquid are controlled.
[0025]
Returning to FIG. 3, by detecting the amount of liquid stored in the weighing tank 30 by the liquid level meter 35, the weighing in the weighing tank 30 becomes accurate. However, as described above, the substrate processing apparatus 100 is normally operated continuously for a long time, and the liquid level meter 35 causes an error due to the drift of the semiconductor pressure element when used for a long time. (See FIG. 6). Therefore, the weighing tank of the substrate processing apparatus according to the present invention maintains the accuracy of the liquid level meter 35 by adopting the following processing mode.
[0026]
FIG. 4 is a flowchart showing a processing procedure in the weighing tank 30. This processing procedure is executed by the control unit 60 in accordance with a processing program inputted in advance. The same processing procedure is also executed in the weighing tanks 40 and 50.
[0027]
First, it is determined by the control unit 60 whether or not weighed ammonia water is put into the immersion tank 20 from the weighing tank 30 (step S1). When starting the injection of the ammonia water, the process proceeds to step S <b> 2, and the control unit 60 opens the injection valve 32 to input the ammonia water into the immersion tank 20. Of course, the supply valve 31 is closed at this stage.
[0028]
Next, it progresses to step S4 from step S3, all the ammonia water stored in the weighing tank 30 is thrown into the immersion tank 20, and it waits for the fixed time until the inside of the weighing tank 30 becomes empty. Whether or not the inside of the weighing tank 30 has been emptied may be determined by the control unit 60 based on the detection result by the liquid level meter 35.
[0029]
If the inside of the weighing tank 30 becomes empty, it will progress to step S5 and the control part 60 will transmit a reset signal to the liquid level meter 35. FIG. The liquid level meter 35 that has received the reset signal executes zero point correction (step S6). That is, when the inside of the weighing tank 30 is empty, the liquid amount is naturally zero. The zero point correction is an operation for correcting the reference of the output value by forcibly setting the output of the liquid level meter 35 to zero when the liquid amount is zero.
[0030]
When the zero point correction of the liquid level meter 35 is completed, the control unit 60 opens the supply valve 31 and supplies new ammonia water to the weighing tank 30. At this stage, the input valve 32 is closed. When the control unit 60 determines that a predetermined amount of ammonia water is stored in the weighing tank 30 based on the liquid level detection result of the liquid level meter 35, the supply of new ammonia water is stopped and the step is again performed. Return to S1.
[0031]
Looking at the contents of the processing procedure shown in FIG. 4, processes other than steps S5 and S6 are also performed in normal substrate processing. That is, also in normal substrate processing, processing up to step S4 (liquid charging processing) is performed, the inside of the weighing tank 30 is once emptied, and then processing in step S7 (new liquid supply processing) is performed. The inside of the weighing tank 30 is again filled with a predetermined amount of ammonia water.
[0032]
On the other hand, in order to perform the zero point correction of the liquid level meter 35, it is necessary to carry out in a state where the inside of the weighing tank 30 is empty. In the substrate processing apparatus according to the present invention, zero correction of the liquid level meter 35 is performed using a period in which the inside of the weighing tank 30 is once empty between the normal liquid supply process and the new liquid supply process. Is doing.
[0033]
That is, when the contents of the processing procedure shown in FIG. 4 are collected, the liquid supply process and the new liquid supply process are alternately repeated as a normal series of substrate processes. The zero point correction of the liquid level meter 35 is performed by effectively using the interval between the processes.
[0034]
In this way, each time the liquid charging process is performed and the inside of the weighing tank 30 is emptied, the zero level correction of the liquid level meter 35 is performed, so that the substrate processing apparatus 100 operates continuously for a long period of time. Even if the measurement is performed, the output value of the liquid level meter 35 is corrected intermittently, and the drift amount of the semiconductor pressure element is always suppressed to a negligible level. As a result, the weighing tank is always highly accurate. The amount of liquid in 30 can be detected.
[0035]
Further, since the zero point correction of the liquid level meter 35 is performed between the normal liquid charging process and the new liquid supply process, the output value of the liquid level meter 35 can be adjusted without reducing the productivity of the apparatus. . That is, conventionally, the output value of the liquid level meter 35 is adjusted when a concentration meter (not shown) attached to the immersion tank 20 detects an abnormal concentration of the mixed chemical solution and issues an alarm, or periodic maintenance. It was limited at times. In any of these cases, the entire substrate processing apparatus 100 is temporarily stopped and the liquid level meter 35 is adjusted, and a reduction in productivity is inevitable. In particular, when the densitometer attached to the dipping bath 20 issues an alarm, the substrate processing is interrupted, resulting in a processing failure for the substrate in the middle of processing, resulting in a significant reduction in productivity.
[0036]
In the substrate processing apparatus 100 according to the present invention, since the zero correction of the liquid level meter 35 is performed between the normal liquid supply process and the new liquid supply process, the liquid level meter 35 can be operated without stopping the apparatus. Adjustments can be made. Further, since the amount of liquid in the weighing tank 30 is always detected with high accuracy, a situation in which the mixed chemical solution in the dipping tank 20 becomes abnormal in concentration and an alarm is generated cannot occur. Therefore, there is very little concern that the productivity of the substrate processing apparatus 100 is lowered.
[0037]
<4. Modification>
While the embodiments of the present invention have been described above, the present invention is not limited to the above examples. For example, in the above embodiment, the controller 60 automatically performs the zero point correction of the liquid level meter 35 between the liquid supply process and the new liquid supply process. The part may be performed manually. FIG. 5 is a flowchart showing another processing procedure in the weighing tank 30.
[0038]
The processing contents in steps S51 and S52 in FIG. 5 are the same as the processing contents in steps S1 and S2 in FIG. Next, in the processing procedure of FIG. 5, it is confirmed whether or not the inside of the weighing tank 30 is emptied by the operator of the apparatus (step S53). At this time, confirmation may be performed by a screen panel (not shown) provided in the substrate processing apparatus 100.
[0039]
In step S54, the operator manually resets the liquid level meter 35. This process may be performed, for example, by pressing a reset button of the liquid level meter 35 provided in the substrate processing apparatus 100. And the liquid level meter 35 which received the reset signal performs zero point correction | amendment (step S55). The subsequent new liquid supply process (step S56) is the same as the process of step S7 of FIG.
[0040]
That is, the operator performs only the process of confirming that the weighing tank 30 is empty and transmitting a reset signal to the liquid level meter 35. Even in this case, the amount of liquid in the weighing tank 30 can always be detected with high accuracy, as described above.
[0041]
Moreover, although the said embodiment was description about the weighing tank 30, it is needless to say that the same technique is applicable also to the weighing tanks 40 and 50. Moreover, it is not limited to a weighing tank, For example, you may apply said technique to the chemical | medical solution tanks CB1 and CB2. In other words, as a normal process, a process of supplying a treatment liquid to a tank and storing a predetermined amount (liquid supply process) and a process of discharging the stored process liquid from the tank (liquid discharge process) are alternately repeated. If this is the case, the amount of liquid in the tank is detected with high accuracy regardless of the operation time of the apparatus by correcting the zero point of the liquid level meter between the liquid discharge process and the next liquid supply process. It can be done. Furthermore, the liquid level meter 35 is not limited to the one using a semiconductor pressure element, and may be one that detects the liquid level using ultrasonic waves.
[0042]
【The invention's effect】
As described above, according to the present invention, when performing a series of processing, after the processing liquid is discharged from the tank and before a new processing liquid is supplied to the tank, the liquid amount detection means Because the zero point correction is performed every time the inside of the tank becomes empty, the liquid amount in the tank can always be detected with high accuracy without lowering the productivity even in the case of continuous operation for a long time. .
[Brief description of the drawings]
FIG. 1 is a schematic front view showing an example of the overall configuration of a substrate processing apparatus according to the present invention.
2 is a view showing a schematic configuration of a chemical tank of the substrate processing apparatus of FIG. 1;
FIG. 3 is a diagram showing a main configuration of the weighing tank of FIG. 2;
4 is a flowchart showing a processing procedure in the weighing tank of FIG. 3;
FIG. 5 is a flowchart showing another processing procedure in the weighing tank of FIG. 3;
FIG. 6 is a diagram showing an error due to drift of a semiconductor pressure element.
[Explanation of symbols]
20 Immersion tank 25 Recovery tank 30, 40, 50 Weighing tank 35 Liquid level meter 36 Tube 60 Control unit 100 Substrate processing apparatus CB1, CB2 Chemical liquid tank WB1, WB2, FR Flushing tank W Substrate

Claims (3)

A substrate processing apparatus for performing a series of processes by repeatedly supplying a processing liquid for processing a substrate to a tank and storing the predetermined amount, and discharging the processing liquid stored in the predetermined amount from the tank,
(a) liquid amount detection means for detecting the amount of liquid stored in the tank;
(b) control means for controlling the liquid amount detection means to perform zero point correction on the liquid amount detection means;
With
Wherein, during the series of processing, after it said processing liquid from said tank is discharged, until liquid new processing to the tank is supplied, the zero point correction in the liquid amount detecting means A substrate processing apparatus, which is performed every time the inside of a tank becomes empty . A substrate processing method for performing a series of processing by repeating a supply step of supplying a processing liquid for processing a substrate to a tank and storing a predetermined amount and a discharging step of discharging the processing liquid stored in the predetermined amount from the tank. And
A correction step in which the zero point correction of the liquid amount detecting means for detecting the liquid amount stored in the tank is performed every time the inside of the tank becomes empty after the discharge process is completed and before the transition to a new supply process. A substrate processing method comprising: A substrate processing apparatus for performing a series of processes by repeatedly supplying a processing liquid for processing a substrate to a tank and storing a predetermined amount, and discharging the processing liquid stored in the predetermined amount from the tank,
A liquid level sensor that detects the amount of the treatment liquid by measuring the atmospheric pressure when releasing the gas from the tube whose tip is submerged in the treatment liquid stored in the tank;
A control unit that transmits a reset signal to the liquid level sensor to perform zero point correction;
With
In the series of processing, the control unit performs zero point correction on the liquid level sensor after the processing liquid is discharged from the tank and before a new processing liquid is supplied to the tank. A substrate processing apparatus.

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