JPH09260333A - Substrate processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate processor capable of mixing very accurately a chemical liquid in pure water. SOLUTION: A substrate processor comprises: a processing bath 2 for processing a substrate W; a chemical liquid tank 3 for storing a chemical liquid; a chemical liquid mixing part 4; a pure water supply part 5 for supplying pure water to the chemical liquid mixing part 4; and a syringe structure 6 for supplying the chemical liquid in the chemical liquid tank 3 to the chemical liquid mixing part 4. When the chemical liquid is mixed with the pure water and it is supplied to the processing bath 2, the pure water is supplied from the pure water supply part 5 to the chemical liquid mixing part 4. By opening an opening and shutting valve 35, a supply passage 34 of the chemical liquid which reaches from the syringe mechanism 6 to the chemical liquid mixing part 4 is released, and also by shutting an opening and shutting valve 33, a supply passage 32 of the chemical liquid which reaches from the chemical liquid tank 3 to the syringe mechanism 6 is closed. Thereafter, a piston 9 of the syringe mechanism 6 is dropped and the chemical liquid in a cylinder 8 is sprayed towards the chemical liquid mixing part 4.

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 for performing processing such as cleaning on a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display panel.

[0002]

2. Description of the Related Art As a kind of such substrate processing apparatus,
It is known that a treatment liquid generated by mixing a chemical liquid in pure water is supplied to a treatment tank and a substrate is treated with the treatment liquid. This substrate processing apparatus has a pure water supply passage for supplying pure water from a pure water supply source to a processing tank and a pressure-proof sealed structure, as described in, for example, Japanese Patent Laid-Open No. 7-22369. A chemical tank for storing the chemical solution,
Nitrogen gas supply means for supplying nitrogen gas into the chemical solution tank, a chemical solution supply path for guiding the chemical solution from the chemical solution tank to the pure water supply path, and a chemical solution mixed with pure water in the pure water supply path And a chemical liquid introduction valve for. Then, by pressurizing the chemical liquid in the chemical liquid tank by supplying nitrogen gas into the chemical liquid tank, by opening the chemical liquid introduction valve,
The chemical solution is pressure-fed into pure water, whereby the pure water and the chemical solution are mixed.

In such a substrate processing apparatus, if the pressure loss in the chemical supply path is constant, the pressure of the chemical pressurized by nitrogen gas and the pure water supply pressure are controlled to be constant values. By doing so, the chemical liquid can be accurately supplied into pure water.

[0004]

In such a substrate processing apparatus, hot pure water at a high temperature may be used instead of pure water at a normal temperature depending on the process step, for example. In such a case, due to the effect of thermal expansion, the orifice of the chemical solution supply path connected to the pure water supply path becomes large, and the pressure loss that the chemical solution receives in the chemical solution supply path changes. Therefore, even when the pressure of the chemical liquid pressurized by the nitrogen gas and the supply pressure of the pure water are controlled to be constant values, the chemical liquid supply amount is not exactly constant.

Further, in order to solve such a problem,
It is possible to arrange a flow rate adjustment valve in the chemical solution supply path and control the flow rate by adjusting this flow rate adjustment valve, but especially when supplying a chemical solution at an extremely small flow rate, the flow rate adjustment valve Is difficult to adjust accurately, and an adjustment error is likely to occur.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a substrate processing apparatus capable of mixing a chemical liquid in pure water extremely accurately.

[0007]

SUMMARY OF THE INVENTION The present invention is a substrate processing apparatus in which a chemical liquid and pure water are mixed and supplied to a processing tank for processing a substrate, the chemical liquid tank storing the chemical liquid, and a piston. And a cylinder, and a syringe mechanism that carries out suction of the chemical liquid into the cylinder and discharge of the chemical liquid from the cylinder by moving the piston, and pure water from a pure water supply source to the treatment tank. Pure water supply path for supplying, mixing means for mixing the pure water in the pure water supply path with the chemical solution discharged from the syringe mechanism, and a supply path of the chemical solution from the chemical solution tank to the syringe mechanism When,
And an opening / closing means for selectively opening a supply path of the chemical liquid from the syringe mechanism to the mixing means.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of a substrate processing apparatus according to the present invention.

This substrate processing apparatus has a processing tank 2 for processing a substrate W, a chemical liquid tank 3 for storing a chemical liquid, a plurality of chemical liquid introduction valves 7a, 7b, 7c, 7d and a pure water supply valve 10. The chemical liquid mixing unit 4 is provided with a pure water supply unit 5 for supplying pure water to the chemical liquid mixing unit 4, and a syringe mechanism 6 for supplying the chemical liquid in the chemical liquid tank 3 to the chemical liquid mixing unit 4.

The processing tank 2 is made of, for example, quartz and has a substrate W immersed in a processing liquid stored therein or overflowing for processing. A recovery unit 12 for recovering the processing liquid overflowing from the upper end of the processing tank 2 is arranged around the processing tank 2, and the recovery unit 12 is connected to a drain (not shown).

The pure water supply unit 5 supplies pure water at room temperature with pure water supply source 13a, hot pure water supply source 13b with high temperature pure water at 50 to 80 degrees Celsius, and open / close valves 14a and 14a.
b, regulators 15a and 15b, a flow meter 16, and
And a pressure sensor 17. When the opening / closing valve 14a is opened, pure water is supplied from the pure water supply source 13a toward the chemical liquid mixing section 4. At this time, the pressure of the pure water in the pure water supply passage 19a from the pure water supply unit 5 to the chemical mixing unit 4 is detected by the pressure sensor 17. Then, by feeding back the detected value to the regulator 15a, the supply pressure of pure water is controlled to be constant. Also, the on-off valve 1
When 4a is closed and the on-off valve 14b is opened, warm pure water is supplied from the warm pure water supply source 13b toward the chemical liquid mixing section 4 at a constant pressure.

The syringe mechanism 6 is for supplying the chemical solution in the chemical solution tank 3 to the chemical solution mixing section 4, and as shown in FIG. 2, a cylinder 8 fixed to a base 22 and an inner diameter of the cylinder 8. And a piston 9 having substantially the same outer diameter as that of the piston 9. The piston 9 is connected to a nut 25 that is screwed with a ball screw 24 via a connecting tool 23. Further, the ball screw 24 is connected via a synchronous belt 26 to a pulse motor 27 as a driving means of the piston 9. Therefore, when the pulse motor 27 is rotated, the nut 25 is driven by the ball screw 24,
It moves up and down while being guided by the guide member 28. Along with this, the piston 9 moves up and down in the cylinder 8. In addition, in FIG. 2, the cylinder 8 and the piston 9 are represented by a cross section.

As shown in FIG. 1, an opening / closing valve 33 is provided in a pipe 32 which constitutes a chemical liquid supply path from the chemical liquid tank 3 to the syringe mechanism 6. Further, an opening / closing valve 35, a filter 36, and a flow meter 3 are provided in a pipe 34 that constitutes a chemical liquid supply path from the syringe mechanism 6 to the chemical liquid mixing unit 4.
7 are provided. These on-off valves 33 and 35 are
It constitutes the opening / closing means.

As shown in FIG. 3, the chemical liquid mixing section 4 has a linear fluid passage 45 inside a main body 44. And
The fluid passage 45 is connected to a pure water supply passage 19a extending from the pure water supply portion 5 to the chemical liquid mixing portion 4 and a pure water supply passage 19b extending from the chemical liquid mixing portion 4 to the processing tank 2. Pure water supplied from the pure water supply passage 19 a passes through the pure water supply port 47 and enters the fluid passage 45. Further, on the downstream side of the pure water supply port 47, the drainage port 4 connected to the drainage pipe 49.
8 are provided. The pure water supply port 47 and the drain port 48 are controlled to open and close by a pure water supply valve 10 and a drain valve 50, respectively. In FIG. 1, the drain pipe 49 and the drain valve 50 are not shown.

On the inner wall of the fluid passage 45, the secondary side flow passages of the four chemical liquid introducing valves 7a, 7b, 7c and 7d are opened. Also, chemical solution inlets 46a, 46
b, 46c, 46d (only 46a is shown in FIG. 3) are formed. These chemical solution inlets 46
Of a, 46b, 46c, 46d, the chemical liquid inlet port 46a
Is connected to the chemical liquid supply unit including the chemical liquid tank 3 and the syringe mechanism 6 described above, and the chemical liquid in the chemical liquid tank 3 is mixed with the pure water in the fluid passage 45 through the chemical liquid inlet 46a. In addition, other chemical liquid inlets 46b, 46c,
46d is connected to each of the other chemical liquid supply units including a chemical liquid tank and a syringe mechanism, receives a chemical liquid different from the chemical liquid in the chemical liquid tank 3, and mixes the chemical liquid with the pure water in the fluid passage 45. To do.

In this embodiment, hydrogen fluoride is stored in the chemical liquid tank 3 connected to the chemical liquid inlet 46a. In addition, each chemical solution inlet 46b, 46c, 4
A chemical solution tank connected to 6d stores ammonia, hydrochloric acid, and hydrogen peroxide, respectively. When the substrate W is etched with hydrofluoric acid, the on-off valve 14a and the pure water supply valve 10 are opened to supply pure water into the fluid passage 45 of the chemical liquid mixing section 4 and the chemical liquid introduction valve. 7
By opening a, hydrogen fluoride in the chemical liquid tank 3 supplied by the syringe mechanism 6 is introduced into the fluid passage 45. Similarly, in the case of performing a cleaning process, which is usually called SC1, on the substrate W, the open / close valve 14b and the pure water supply valve 10 are opened to supply hot pure water into the fluid passage 45, and the chemical solution introduction valve 7b is also provided. And 7d are opened to introduce ammonia and hydrogen peroxide into the fluid passage 45. Further, in the case of performing a cleaning process usually called SC2 on the substrate W, the open / close valve 14b and the pure water supply valve 10 are opened to supply the hot pure water into the fluid passage 45, and the chemical liquid introduction valve 7c and 7d is opened and hydrochloric acid and hydrogen peroxide are introduced into the fluid passage 45.

Next, the operation of mixing the chemical liquid stored in the chemical liquid tank 3 with pure water and supplying the same to the processing tank 2 in the substrate processing apparatus described above will be described.

Prior to supplying the chemical liquid, the chemical liquid in the chemical liquid tank 3 is sucked into the cylinder 8 of the syringe mechanism 6 in advance. This suction operation opens the on-off valve 33,
Also, with the on-off valve 35 closed, the pulse motor 27
Is driven to raise the piston 9 via the nut 25 and the connecting tool 23. Then, the open / close valve 14a in the pure water supply passage 19a and the pure water supply valve 10 in the chemical liquid mixing portion 4 are opened, and pure water is introduced from the pure water supply source 13a into the fluid passage 45 of the chemical liquid mixing portion 4.

Then, the opening / closing valve 33 is closed and the opening / closing valve 35 is opened. Further, the chemical liquid introducing valve 7a in the chemical liquid mixing unit 4 is opened. Then, by driving the pulse motor 27, the piston 9 is lowered at a constant speed via the nut 25 and the connecting tool 23, and the chemical liquid is discharged. As a result, the chemical liquid in the cylinder 8 of the syringe mechanism 6 passes through the filter 36 and the flow meter 37, enters the fluid passage 45 from the chemical liquid introduction valve 7a, and is mixed with the pure water passing therethrough. .

At this time, by lowering the descending speed of the piston 9, it becomes possible to mix a slight amount of the chemical liquid into the pure water. Further, the supply amount of the chemical liquid mixed in pure water per unit time can be controlled to a desired value by accurately controlling the descending speed of the piston 9 by the pulse motor 27. Therefore, the chemical liquid introduction valve 7
Even in the case where the size of the secondary side flow path in a is changed, the supply amount of the chemical solution does not change.

Incidentally, for example, in the step of etching the semiconductor substrate before gate oxidation with hydrofluoric acid by supplying hydrogen fluoride and pure water to the processing tank 2, the hydrogen fluoride and pure water are mixed with each other. The mixing ratio is 1: 200, and the supply flow rate of hydrogen fluoride is about 100 cc / min. According to the syringe mechanism 6 described above, it becomes possible to accurately supply such a minute amount of the chemical liquid while keeping the flow rate constant. Further, the concentration of hydrogen fluoride may be diluted more than that, and for example, the supply flow rate of hydrogen fluoride may be about 20 to 30 cc per minute. As described above, even when the supply amount of the chemical liquid per unit time is further reduced, according to the above-described syringe mechanism 6,
To accurately control the descending speed of the piston 9 at a low speed,
By using a cylinder having a small inner diameter as the cylinder 8, it is possible to maintain the accuracy of supplying the chemical liquid with high accuracy.

When the piston 9 in the syringe mechanism 6 descends to the lowermost end as shown by the chain double-dashed line in FIG. 2 and the chemical liquid in the cylinder 8 is exhausted, the same operation as described above is repeated. Cylinder 8
The chemical solution is introduced into the inside to continue the treatment. That is, when the piston 9 is raised and the chemical liquid is sucked into the cylinder 8, the opening / closing valve 33 is opened to open the pipe 32 from the chemical liquid tank 3 to the syringe mechanism 6, and at the same time, open / close the valve 3
By closing 5, the syringe mechanism 6 is moved to the drug solution mixing unit 4
To close the pipe 34 leading to and to discharge the chemical liquid from the inside of the cylinder 8 by lowering the piston 9 and opening / closing valve 35.
The pipe 34 from the syringe mechanism 6 to the drug solution mixing unit 4 is opened by opening, and the pipe 32 from the drug solution tank 3 to the syringe mechanism 6 is closed by closing the opening / closing valve 33.
Control to close.

In the above-described embodiment, the opening / closing valve 33 is connected to the pipe 32 connecting the syringe mechanism 6 and the chemical liquid tank 3, and the opening / closing valve 33 is connected to the pipe 34 connecting the syringe mechanism 6 and the chemical liquid mixing section 4. Although the case of disposing the respective 35 is described, instead of the opening / closing valve 33, a check valve that allows only the passage of the liquid medicine from the liquid medicine tank 3 toward the syringe mechanism 6 is arranged, and instead of the opening / closing valve 34, the syringe. A check valve that allows only the passage of the chemical liquid from the mechanism 6 toward the chemical liquid mixing portion 4 may be provided. Similarly, the chemical solution supply path from the chemical solution tank 3 to the syringe mechanism 6 and the syringe mechanism 6
It is also possible to use a single solenoid valve or the like that can switch the chemical liquid supply path from the liquid chemical mixing unit 4 to the chemical liquid mixing unit 4.

[0024]

According to the substrate processing apparatus of the present invention,
It is possible to control the supply amount of the chemical liquid to be supplied into pure water by the movement amount of the piston in the syringe mechanism. Therefore, for example, when the pressure loss that the chemical solution receives in the chemical solution supply path is changed or when the pure water supply pressure is changed, or even when a very small quantity of chemical solution is supplied per unit time, It can be supplied very accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a substrate processing apparatus according to the present invention.

FIG. 2 is a side view showing a syringe mechanism 6.

FIG. 3 is a cross-sectional view showing a chemical liquid introducing section 4.

[Explanation of symbols]

 2 Processing Tank 3 Chemical Solution Tank 4 Chemical Solution Mixing Section 5 Pure Water Supply Section 6 Syringe Mechanism 7a Chemical Solution Introduction Valve 8 Cylinder 9 Piston 10 Pure Water Supply Valve 19a Pure Water Supply Path 19b Pure Water Supply Path 27 Pulse Motor 32 Piping 33 Open / Close Valve 34 Piping 35 Open / close valve W substrate

Claims (1)

[Claims] 1. A substrate processing apparatus configured to mix and supply a chemical liquid and pure water to a processing bath for processing a substrate, the chemical treatment tank having a chemical liquid tank for storing the chemical liquid, and a piston and a cylinder. A syringe mechanism that performs suction of a chemical solution into a cylinder and discharge of the chemical solution from the cylinder by moving the piston, and a pure water supply path for supplying pure water from a pure water supply source to the processing tank. A mixing means for mixing the chemical solution discharged from the syringe mechanism with the pure water in the pure water supply path, a chemical solution supply path from the chemical solution tank to the syringe mechanism, and the mixing mechanism from the syringe mechanism. A substrate processing apparatus comprising: an opening / closing unit that selectively opens a chemical solution supply path to the unit.