JPH10128094A - Chemical treating device for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate chemical treating device in which a mixing ratio in a chemical mixture for chemical treatment is easily known. SOLUTION: The prescribed quantities of a chemical A and a chemical B are sent respectively from measuring parts 1, 2 to a mixing part 3, and the prescribed quantity of pure water C is sent to the mixing part 3 by a fixed delivery pump PM. These are mixed to form a liquid chemical mixture D, and the mixture D is sent to a nozzle 6 at the end. The mixture D is jetted to a substrate W from the nozzle 6 to perform chemical treatment. A pH sensor 21 is provided on a pipe 9 downstream of the mixing part 3 to measure the pH value of the mixture D, and based on the measured pH value, a mixing ratio in the mixture D is set to a suitable one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate chemical liquid processing apparatus for performing chemical liquid processing on various substrates such as a semiconductor wafer and a glass substrate for a liquid crystal display using a mixed chemical liquid, and more particularly, to a chemical liquid processing apparatus. The present invention relates to a technique for measuring a mixing ratio of a mixed chemical solution.

[0002]

2. Description of the Related Art An example of this type of substrate chemical processing apparatus is a substrate cleaning apparatus used in a semiconductor element manufacturing process or a liquid crystal display panel manufacturing process. 2. Description of the Related Art A conventional substrate cleaning apparatus is configured to prepare a mixed chemical by mixing two or more types of chemicals measured in advance, and to perform a cleaning process (chemical processing) on a semiconductor wafer or a glass substrate with the mixed chemical. . Specific examples of the chemical liquid mixing include a mixed form of pure water and a chemical liquid, a mixed form of chemical liquids, and the like.

[0003]

However, the above conventional apparatus has the following problems. That is, the mixing ratio depends on the measurement accuracy of each chemical before mixing.
It is difficult to confirm the mixing ratio of the mixed chemicals after they are actually mixed. Of course, it is conceivable to measure the concentration of the drug solution in the mixed drug solution using a densitometer and control the mixture so as to have an appropriate mixing ratio. However, since the densitometer used in this case is very expensive, A new problem arises in that the processing cost increases.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a substrate chemical processing apparatus which can easily know the mixing ratio of a mixed chemical used for chemical processing.

[0005]

To achieve the above object, the present invention has the following arrangement. That is, according to the first aspect of the invention, a chemical liquid supply means for supplying a plurality of types of chemical liquids by predetermined amounts, and the respective chemical liquids supplied from the chemical liquid supply means are mixed, and the hydrogen index is changed according to a change in the mixing ratio. A liquid chemical mixing means for creating a mixed chemical liquid that changes, wherein the substrate chemical liquid processing apparatus configured to perform chemical liquid processing on the substrate using the mixed chemical liquid sent from the chemical liquid mixing means, wherein the pH of the mixed chemical liquid A pH sensor for detecting a value is provided on the chemical mixing means or downstream of the chemical mixing means.

[0006] The invention described in claim 2 is the invention according to claim 1.
In the substrate chemical processing apparatus according to the above, based on a pH value detected by a pH sensor, a mixing ratio determining means for determining whether the mixing ratio of the chemical in the mixed chemical is outside an appropriate ratio, and the mixing ratio An alarm issuance means for issuing an alarm when the judgment means judges that the mixing ratio of the chemical solution is out of an appropriate ratio.

[0007] The invention according to claim 3 provides the invention according to claim 1.
Or the supply of each of the chemicals supplied from the chemical supply means such that the mixing ratio of the mixed chemicals becomes a preset ratio based on the pH value detected by the pH sensor. It is provided with a chemical liquid supply amount control means for controlling the amount.

[0008] The invention described in claim 4 is the first invention.
4. The apparatus for treating a chemical solution of a substrate according to any one of items 3 to 3, further comprising a conversion means for converting the pH value detected by the pH sensor into a chemical solution concentration value and outputting the value.

In the present invention, the type of the chemical for preparing the mixed chemical is not limited as long as the hydrogen index changes according to the change of the mixing ratio of the mixed liquid. Further, pure water is also included in the chemical solution according to the present invention.

[0010]

Next, the operation of the substrate chemical processing apparatus according to the present invention will be described. When performing the chemical treatment by the substrate chemical treatment device of claim 1, a plurality of types of chemicals are sent from the chemical supply means to the chemical mixing means by a predetermined amount, respectively.
The mixed chemicals are mixed by the chemical mixing means. The supply amount of each chemical solution is, of course, an amount corresponding to a preset mixing ratio. The mixed chemical created by the chemical mixing means is
The hydrogen index changes according to the change in the mixing ratio of the chemical solution. The substrate is subjected to the chemical treatment with the mixed chemical obtained in this manner.

On the other hand, in the case of the apparatus of the present invention, a pH value indicating the hydrogen index of the mixed chemical solution is detected by the pH sensor. p
Since the mixed chemical solution to be measured by the H sensor changes the hydrogen index according to the change in the mixing ratio of the chemical solution, p
The pH value detected by the H sensor has a correlation with the mixing ratio of the drug solution in the mixed drug solution. Based on this pH value, the appropriateness of the mixing ratio can be determined.

In the apparatus for treating a chemical solution of a substrate according to claim 2,
Based on the pH value detected by the sensor, the mixing ratio determining means determines whether or not the mixing ratio of the mixed drug solution is out of an appropriate ratio. If the result of this determination is that the mixing ratio of the chemical solution is out of the appropriate ratio, an alarm is issued from the alarm generating means.

According to the third aspect of the present invention, the pH of the substrate
Based on the pH value detected by the sensor, the supply amount of the chemical solution is automatically controlled by the chemical solution supply amount control means so that the mixing ratio of the mixed chemical solution becomes a preset ratio.

According to a fourth aspect of the present invention, there is provided an apparatus for treating a chemical solution of a substrate, wherein
The pH value detected by the sensor is converted to a chemical solution concentration value by the conversion means, and based on the converted concentration value,
For example, it is possible to display the measured concentration, to determine whether the mixing ratio is out of an appropriate ratio, or to control the supply amount of the chemical solution for adjusting the mixing ratio.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an overall configuration of a substrate chemical solution processing apparatus according to an embodiment, FIG. 2 is a block diagram illustrating a configuration of a control system of the embodiment apparatus, and FIGS.
FIG. 5 is a partial cross-sectional view illustrating a detailed configuration of a measuring unit that measures a chemical solution in the example device.

The processing apparatus shown in FIG. 1 is generally configured as follows. Chemical liquids A and B are each a measuring section (chemical liquid supply means)
The weight is measured to be a predetermined amount in 1 and 2. The measured liquid chemicals A and B are supplied to the mixing section (chemical liquid mixing means) 3, and a predetermined amount of pure water C is supplied to the mixing section 3. These are mixed in the mixing section 3 to form a mixed chemical solution. The mixed chemical solution is discharged from the nozzle 6 onto the substrate W to be cleaned through the accumulation / feed units 4 and 5, whereby the chemical solution processing is performed.

In the mixed chemical, the hydrogen index changes according to the change in the mixing ratio of the chemical. Examples of the chemical include aqueous hydrogen peroxide, aqueous ammonia, and hydrofluoric acid. In the present invention, pure water is also one of the chemicals. Substrates to be subjected to chemical treatment include semiconductor wafers and glass substrates, but are not limited to these substrates. Examples of the chemical treatment include a cleaning treatment and an etching treatment, but are not limited to these treatments. Hereinafter, the configuration of each unit of the embodiment device will be described more specifically.

A tank 7 for storing a chemical solution A and a tank 8 for storing a chemical solution B are disposed upstream of the measuring sections (chemical solution supply means) 1 and 2. The chemical solution A is sent to the measuring unit 1 via the pipe P1 and the valve V1, while the chemical solution B is sent to the measuring unit 2 via the pipe P2 and the valve V2.

As shown in FIG. 3, the measuring section 1 has a pipe P1 for introducing the chemical solution A and a pipe P3 for supplying the measured chemical solution A to the mixing section 3, which are connected to the bottom of the measuring tank 9. . In addition, a pipe P4 for discharging excess chemical solution A is attached to the upper part of the measuring tank 9 so as to be able to move up and down through the upper surface. The end of the pipe P4 is a measuring tank 9
And a rear end thereof is connected to the aspirator 10 via a flexible pipe P5 having flexibility. A screw is cut on the outer peripheral surface of the pipe P4.
A gear 11 whose inner surface is threaded is screwed to the pipe P4 so that it can rotate only, that is, does not move up and down. A gear 13 connected to an output shaft of the pulse motor M meshes with the gear 11. When the pulse motor M rotates in the forward and reverse directions, the gear 11 rotates at that position, and as a result, the pipe P4 screwed to the gear 11 moves up and down.

A valve V upstream of the aspirator 10
When 3 opens, a flow occurs from the inlet to the outlet as shown by the arrow in the aspirator 10, and a suction force is generated in the suction port 10a accordingly. At this time, the pipe P
If the tip of the liquid 4 is below the liquid level of the chemical A, the liquid A is discharged through the route of the pipe P4 → the pipe P5 → the aspirator 10 → the waste liquid tank 14, so that the liquid level of the chemical A
4 matches the height of the tip. That is, the aspirator 1
With the action of 0, the liquid A is measured when the liquid level of the liquid A always coincides with the height of the tip of the pipe P4. Therefore,
In the case of the measuring section 1, if the height of the tip of the pipe P4 is changed, the amount of the medicinal solution A to be measured will change. In addition, it is good also as a structure which recirculates excess chemical | medical solution A discharged | emitted by the aspirator 10 to the tank 7, and reuses the chemical | medical solution A. When the measurement of the solution A is completed, the solution A
Is extruded by the pressure of the N ₂ gas introduced from the pipe PN1 through the valve VN1, and
Will be supplied to

The measuring section 2 has the same configuration as the measuring section 1. That is, as shown in FIG. 4, a pipe P2 for introducing the chemical solution B and a pipe P6 for supplying the measured chemical solution B to the mixing unit 3 are connected to the bottom of the measuring tank 15, and the excess chemical solution B is removed. A pipe P7 for discharging is provided so as to be able to move up and down through the upper surface of the measuring tank 15. However, the weighing unit 2 does not include a motor for automatically moving the pipe P7 up and down. Further, N ₂ gas for pushing out the measured chemical solution B is introduced into the measuring tank 15 via the valve VN2 and the pipe PN2.

Further, in the case of the embodiment, in addition to the chemicals A and B, a predetermined amount of pure water (chemical) C is supplied from the pure water tank 16 by a metering pump (chemical supply means) PM to the mixing section 3 via a pipe P8. Supplied to

The mixing section 3 has a mixing tank 17, and a pipe P 9 for sending a mixed chemical is connected to the bottom of the mixing tank 17. In addition, pipes P3, P6, P8 for introducing chemicals A, B and pure water C are provided above mixing tank 17.
Is connected. In the mixing tank 17, a stirrer (not shown) is provided as needed.

After the valves V5 and V6 are opened and a predetermined amount of the chemicals A and B are introduced into the mixing tank 17, a predetermined amount of pure water C is introduced into the mixing tank 17 via the metering pump PM. The mixed chemicals are produced by stirring and mixing according to the conditions. When the preparation of the mixed chemical solution is completed, the mixed chemical solution D is sent from the pipe P9 to the storage / feed units 4 and 5 by the pressure of the N ₂ gas introduced from the pipe PN3 via the valve VN3.

The storage / feed unit 4 includes a storage tank 18, and a feed pipe P 10 is connected to the bottom of the storage tank 18. Further, a pipe P9 is connected to an upper portion of the storage tank 18. When the mixed chemical D is introduced into the storage tank 18, only the valve V7 is opened to receive the mixed chemical D. When sending the mixed chemical solution D, the valve V9 is opened and the valve V
The mixed chemical solution D is supplied to the pipe P10 and the pipe P1 by the pressure of the N ₂ gas introduced from the pipe PN4 via N4.
2 to nozzle 6.

Similarly, the storage / feed unit 5 also includes a storage tank 19, and a feed pipe P11 is connected to the bottom of the storage tank 19, and a pipe P9 is connected to the top thereof. When the mixed chemical D is introduced into the storage tank 19, only the valve V8 is opened to receive the mixed chemical D. When sending the mixed chemical D, the valve V10 is opened, and the mixed chemical D is sent to the nozzle 6 through the pipes P10 and P12 under the pressure of the N ₂ gas introduced from the pipe PN5 via the valve VN5.

Note that one of the accumulating and feeding units 4 and 5 is configured to perform an accumulating operation while one of the accumulating and feeding units 4 and 5 performs an accumulating operation, so that the mixed chemical solution D can be supplied to the nozzle 6 without a break.

A mounting table 20 on which a substrate W to be treated with a chemical solution is placed.
Are connected and supported by a rotating shaft 20a driven by a motor (not shown). In addition, although not shown, around the mounting table 20, there are also provided components necessary for performing automatic loading and unloading of the substrate W.

Next, the pH of the mixed chemical solution, which is a feature of the present invention,
A configuration related to the pH sensor that detects a value will be described. As shown in FIG. 1, a pipe P downstream of the mixing section 3
9, a pH sensor 21 is provided. The pH sensor 21 is provided with a mixed chemical solution D sent from the mixing unit 3.
Is constantly detected and output to the control unit 22 as an electric signal. As shown in FIG. 2, the control unit 22 includes an A / D converter 2 for digitizing an electric signal from the pH sensor 21.
3. Lookup table 24 for converting the pH value to a concentration value, a reference concentration memory 25 for storing a reference concentration corresponding to an appropriate mixing ratio of the chemical solution, a control CP
A U (central processing unit) 29 is provided.

The CPU 29 has the following three main functions. First, the digitized pH value is converted into a concentration value with reference to a concentration conversion look-up table 24 schematically shown in FIG.
6 is displayed. Second, the measured concentration is compared with the reference concentration, and if there is a difference (deviation) between the measured concentration and the reference concentration that is equal to or greater than a certain value, it is determined that the mixing ratio is not an appropriate ratio, and an alarm (alarm generating means) ) An alarm is generated from 27). Third,
The motor control unit 28 outputs a signal for rotating the pulse motor M by an amount corresponding to the difference between the measured density and the reference density.
The CPU 29 corresponds to the mixing ratio determining means and the chemical liquid supply amount controlling means in the present invention. Further, the look-up table 24 corresponds to a conversion unit in the present invention.

In this embodiment, the supply amounts of the chemical solution B and the pure water C are not controlled, but the supply amount of the chemical solution A is controlled so that the mixing ratio of the mixture becomes an appropriate ratio. Of course, the supply amounts of the chemical solution B and the pure water C may be controlled.

Next, a description will be given of a chemical solution processing operation by the embodiment apparatus having the above-described configuration. First, the valves V1 and V2 are respectively opened for a predetermined time, and the chemicals A and B are respectively supplied from the tanks 7 and 8 to the measuring tanks 9 and 8, respectively.
15 into the pipes P4 and P7 up to the height indicated by the one-dot chain lines H1 and H2 (see FIGS. 3 and 4). . Then, the tips of the pipes P4 and P7 are slightly lower than the liquid levels of the chemical solution A and the chemical solution B. Then, aspirator 1
0 operates, and the chemicals A, B from the tips of the pipes P4, P7.
Suck out. When the liquid surface of the chemical solution A or the chemical solution B drops to the height indicated by the one-dot chain lines H3 and H4 (see FIGS. 3 and 4) which are substantially equal to the ends of the pipes P4 and P7, the suction of the chemical solution stops naturally. As a result, the chemicals A and B are measured to the predetermined amounts.

Next, the valves V5 and V6 are opened, and N ₂ gas is introduced into the measuring tanks 9 and 15, and the chemicals A and B are supplied from the measuring tanks 9 and 15 to the mixing tank 17 at the pressure of the N ₂ gas.
Then, a predetermined amount of pure water C is sent to the mixing tank 17 by the metering pump PM to generate a mixed chemical solution D. Thereafter, with opening the valve V7, and N ₂ gas was introduced into the mixing tank 17, chemical-liquid mixing at a pressure of N ₂ gas D
From the pipe 9 to the storage tank 18 via the valve V7.

When the accumulation of the mixed drug solution D in the storage tank 18 is completed, the valve V9 is opened and N ₂ is stored in the storage tank 18.
Gas is introduced, and the mixed chemical solution D is applied to the nozzle 6 with the pressure of N ₂ gas.
To perform chemical treatment. On the other hand, chemicals A and B
The measuring / mixing operation is started again in the same manner, and the obtained mixed chemical solution D is sent to the empty storage tank 19 to be stored. When the storage tank 18 becomes empty, the mixed chemical solution D is sent from the storage tank 19 to the nozzle 6, while the mixed chemical solution D is similarly stored toward the storage tank 18. The above operation is repeated until the chemical treatment is completed.

When the mixed chemical D is sent out from the mixing tank 17, the pH value of the mixed chemical D is measured by the pH sensor 2.
Measure according to 1. The measured pH value is provided to the control unit 22. The CPU 29 of the control unit 22 converts the pH value into a concentration value in accordance with the concentration conversion look-up table 24, and displays it on the display unit 26. Further, the CPU 29 compares the measured density with the reference density, and if there is a certain difference (deviation) between the two, it is determined that the mixture ratio is out of the appropriate ratio, and the alarm 27 issues an alarm. And inform the worker.
Further, the CPU 29 outputs a control signal for raising and lowering the pipe P4 of the measuring section 1 to the pulse motor M via the motor control section 28 according to the difference in the density.

The pulse motor M which has received the signal from the motor control unit 28 moves the pipe P4 upward or downward by a required amount. Since the height of the tip of the pipe P4 changes with the movement of the pipe P4, and the supply amount of the chemical solution A changes to an appropriate amount, the mixing ratio automatically returns to an appropriate ratio.

The present invention is not limited to the above embodiment, but may be modified as follows, for example. (1) In the above embodiment, the mixed chemicals are chemicals A and B and pure water C
, But the mixed chemicals were chemicals A and B
Or a chemical solution A and pure water C or a chemical solution B and pure water C.

(2) In the control unit 22 of the above embodiment, the pH
Although the value is used after being converted into a concentration value, the pH value may be displayed as it is without being converted into a concentration value, or may be compared with a pH value corresponding to a preset mixing ratio.

(3) In the above embodiment, the substrate W is treated with the chemical solution one by one. However, a mixed chemical solution is put into a tank, and a large number of substrates are immersed in the tank at once. The structure which performs a chemical | medical solution process may be sufficient.

(4) In the above embodiment, the predetermined amounts of the chemicals A and B were obtained using the measuring tank, but the predetermined amounts of the chemicals A and B were sent to the mixing unit 3 using the metering pump. Is also good.

(5) In the above embodiment, the pH sensor 21 is disposed downstream of the mixing tank 17, but the pH sensor 21 may be disposed in the mixing tank 17. In this case, if the mixing tank 17 can be replenished with an appropriate amount of the chemical, the mixing tank 1
7, the mixing ratio of the mixed chemicals can be corrected.

[0042]

According to the first aspect of the present invention, the mixing ratio of the chemical solution in the mixed chemical solution can be known in real time by the pH sensor. In addition, since a pH sensor that is generally less expensive than a densitometer is used, the cost of the chemical solution treatment device can be reduced.

According to the second aspect of the present invention, the fact that the mixing ratio of the chemical solution in the mixed chemical solution is out of the appropriate ratio can be known by the alarm from the alarm generating means, which is very convenient. .

According to the third aspect of the present invention, the supply amount of the chemical liquid is automatically controlled by the chemical liquid supply amount control means so that the mixing ratio of the chemical liquid in the mixed chemical liquid becomes a preset ratio. The mixing ratio of the chemicals can be reliably set to an appropriate ratio.

According to the fourth aspect of the present invention, since the pH value of the mixed chemical is converted into the concentration of the chemical, it is easy to grasp the concentration of the mixed chemical.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a substrate chemical solution processing apparatus according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a control unit of the apparatus according to the embodiment.

FIG. 3 is a partial cross-sectional view showing a detailed configuration of a measuring section for a medical solution A in the apparatus of the embodiment.

FIG. 4 is a partial cross-sectional view showing a detailed configuration of a measuring section for a medical solution B in the apparatus of the embodiment.

FIG. 5 is a graph showing a conversion characteristic between a pH value of a mixed drug solution and a drug solution concentration.

[Explanation of symbols]

 Reference numerals 1 and 2: Measuring unit (chemical liquid supply means) 3 ... Mixing unit (chemical liquid mixing means) 21 ... pH sensor 24 ... Concentration conversion look-up table (conversion means) 25 ... Reference concentration memory 27 ... Alarm device 28 ... Motor control unit 29: CPU A, B: Chemical solution C: Pure water D: Mixed chemical solution M: Pulse motor W: Substrate

Claims (4)

[Claims] 1. A chemical liquid supply means for supplying a predetermined amount of each of a plurality of types of chemical liquids, and each of the chemical liquids supplied from the chemical liquid supply means are mixed to form a mixed chemical liquid whose hydrogen index changes according to a change in the mixing ratio. A pH sensor for detecting a pH value of the mixed chemical in a substrate chemical processing apparatus configured to perform chemical processing on a substrate using the mixed chemical delivered from the chemical mixing means. Is disposed downstream of the chemical mixing means or the chemical mixing means. 2. The substrate chemical processing apparatus according to claim 1, wherein the pH value detected by the pH sensor is
Mixing ratio determining means for determining whether the mixing ratio of the chemical liquid in the mixed chemical liquid is out of an appropriate ratio, and when it is determined by the mixing ratio determining means that the mixing ratio of the chemical liquid is out of the appropriate ratio A substrate chemical solution treatment device having an alarm generating means for generating an alarm. 3. The chemical liquid processing apparatus for a substrate according to claim 1, wherein the chemical liquid supply means is configured such that a mixing ratio of the mixed chemical liquid becomes a preset ratio based on a pH value detected by a pH sensor. A substrate chemical solution processing apparatus comprising a chemical solution supply amount control means for controlling the supply amount of each chemical solution supplied from the substrate. 4. The substrate chemical processing apparatus according to claim 1, further comprising a conversion unit configured to convert a pH value detected by the pH sensor into a chemical solution value and output the converted value. Chemical treatment equipment.