JP3074089B2 - Substrate processing equipment - Google Patents

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,
The present invention relates to a substrate processing apparatus for surface-treating a thin plate-like substrate (hereinafter, simply referred to as a “substrate”) such as a semiconductor substrate or a glass substrate for a liquid crystal or a photomask.

[0002]

2. Description of the Related Art A substrate is immersed in a processing solution filled in a processing tank,
In a so-called overflow type substrate processing apparatus, a processing solution such as a chemical solution or pure water is supplied from the lower portion of the processing tank and overflows from the upper edge of the processing tank to perform surface treatment on the substrate. The overflowing processing liquid is collected by a processing liquid recovery tank formed at the upper part of the outer periphery of the processing tank, circulated and filtered, and reused, thereby reducing maintenance costs.

[0003] Such an overflow type substrate processing apparatus has the advantage that the processing time can be greatly reduced because a clean processing liquid is always supplied to the substrate surface. Since the fluid constantly circulates and overflows, the chance of contact with the atmosphere increases, and unnecessary components in the atmosphere, particularly oxygen, are dissolved in the processing solution, and the amount of dissolved oxygen in the processing solution increases.

Also, in a substrate processing apparatus of a type in which a processing liquid overflowing from a processing tank is discarded into a waste liquid tank without being reused, the amount of dissolved oxygen in the processing liquid increases due to contact between the processing liquid and the atmosphere. I do.

[0005] Such an increase in the amount of dissolved oxygen in the processing solution is not very desirable in the surface treatment of the substrate. For example, when a silicon substrate having an oxide film formed on its surface is cleaned with pure water, the dissolved oxygen in the pure water promotes the growth of a natural oxide film on the silicon substrate surface. When the oxide film formed on the surface of the substrate is a gate oxide film, the thickness of the oxide film is adjusted to about several tens of angstroms, so that the growth of the natural oxide film is critical to the accuracy of the substrate processing. This results in disability.

[0006] In order to prevent the amount of dissolved oxygen in the processing solution from increasing due to contact with the atmosphere, a method of blowing an inert gas such as nitrogen gas onto the surface of the processing solution filled in the processing tank has been conventionally used. Was. One example is disclosed in
Japanese Patent Application Publication No. 97525 discloses a technique as shown in FIG. In the figure, a processing liquid recovery tank 2 is provided integrally with the processing tank 1 at the upper part of the outer periphery of the processing tank 1 filled with the processing liquid L, and the processing liquid L overflowing from the upper edge of the processing liquid 1 is The processing liquid supply port 4 provided in the center of the bottom of the processing tank 1 is collected by the processing liquid recovery tank 2 and drained from the drain port 3, and is processed by a processing liquid circulation device (not shown).
Is supplied and used for circulation.

Above the processing tank 1, a pair of nitrogen gas ejection pipes 5 and 6 are provided symmetrically in a direction perpendicular to the plane of the paper, and nitrogen gas supplied from a nitrogen gas supply device (not shown) is The gas is ejected from the ejection holes 5a, 6a provided in a row on each side surface of the gas ejection pipes 5, 6 toward the liquid surface of the processing liquid L filled in the processing tank 1, and a nitrogen gas atmosphere is formed on the liquid surface of the processing liquid L. To form

As a result, the overflowing treatment liquid L
However, since it is circulated without directly contacting the atmosphere, it is possible to greatly suppress the increase in the amount of dissolved oxygen due to the oxygen in the atmosphere being dissolved in the processing liquid L.

[0009] In addition, 7 provided on the bottom portion of the processing tank 1
Is a substrate transport container (carrier) containing multiple substrates
Is provided with a plurality of holes 7a, and the processing liquid L supplied from the processing liquid supply port 4 is provided.
Is uniformly supplied to the immersed substrate in a state of being rectified and rectified by the holes 7a.

[0010]

However, in the configuration of the conventional substrate processing apparatus as described above, the nitrogen gas is merely sprayed from obliquely above the surface of the processing liquid L, so that the nitrogen gas is dissipated. As a result, a large amount of nitrogen gas is required to completely shut off the atmosphere and the processing liquid L, resulting in a problem that the cost is increased. Also, in a substrate processing apparatus, clean air is usually down-flowed from above the processing tank 1 and exhausted from below through the periphery of the processing tank 1 to exhaust harmful gas generated during substrate processing. However, the nitrogen gas is further diffused under the influence of the exhaust gas of the downflow, so that the supply amount of the nitrogen gas must be further increased, and it is necessary to balance with the exhaust gas amount.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to prevent unnecessary components in the atmosphere from being dissolved in a processing solution by a simple and inexpensive structure. Provide a substrate processing apparatus capable of

[0012]

In order to achieve the above object, a substrate processing apparatus according to a first aspect of the present invention supplies a processing liquid into a processing tank holding a substrate to overflow the processing liquid, and In a substrate processing apparatus that performs a surface treatment, an inert gas supply unit that blows an inert gas onto a processing liquid surface of the processing tank through a jet unit, and an exhaust port that is provided to face the jet unit. An exhaust means for exhausting an inert gas, and a cover member provided around an upper edge of the processing tank in order to prevent diffusion of the inert gas sprayed on the surface of the processing liquid; A processing liquid recovery tank for collecting the overflowed processing liquid is provided on the outer periphery, and a lower end of the cover member is immersed in the processing liquid stored in the processing liquid recovery tank. .

According to a second aspect of the present invention, in the substrate processing apparatus of the first aspect, the inert gas supply means detects a discharge amount by the discharge amount adjusting means for controlling a discharge amount of the inert gas and an exhaust amount by the exhaust means. An exhaust amount detection unit; and a control unit that controls the operation of the ejection amount adjustment unit based on a detection signal from the exhaust amount detection unit. An appropriate amount is controlled in accordance with the amount of exhaust by the means.

[0014]

According to the first aspect of the present invention, since the periphery of the upper edge of the processing tank is surrounded by the cover member, the inert gas blown out from the jetting means of the inert gas supply means is:
It is supplied only to the processing liquid surface without dissipating. The blown-in inert gas is exhausted by the exhaust means through an exhaust port provided opposite to the ejection means, so that an inert gas air curtain is formed on the surface of the processing liquid, and the atmosphere and the processing liquid surface are separated. Will be shut off.

Since the lower end of the cover member is disposed so as to be immersed in the processing liquid stored in the processing liquid collecting tank formed around the processing tank, a water seal mechanism is formed at this portion, and the processing tank is formed. In addition, it is possible to easily prevent the inert gas from being dissipated in the portion while easily adjusting the inclination of the gas.

According to the second aspect of the present invention, while controlling the operation of the ejection amount adjusting means by the control means while detecting the exhaust amount by the exhaust amount detecting means, the supply of the inert gas from the inert gas supply means is controlled. Since the amount is appropriately controlled, useless use of an inert gas is eliminated.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the substrate processing apparatus according to the present invention will be described in detail with reference to the drawings. However, it is needless to say that the technical scope of the present invention is not limited thereby.

FIG. 1 is a schematic view of a processing tank portion of a substrate processing apparatus according to the present invention, which is a schematic view in a side vertical section, and FIG. 2 is a schematic cross-sectional view taken along line AA of FIG. FIG. 3 is a perspective view showing the appearance of the outer tub.

Above the outer periphery of the inner tank 10 as a processing tank for the substrate W, a processing liquid recovery tank 11 for collecting the processing liquid overflowing from the upper edge 12 of the inner tank 10 is provided with the inner tank 10. It is formed integrally. Usually, quartz having strong corrosion resistance is used as a material of the inner tank 10 and the processing liquid recovery tank 11, but when a hydrofluoric acid-based processing liquid L is used, a fluorine resin or polychlorinated resin is used. Vinyl (PVC) or the like is used.

The inner tank 10 is mounted on four level adjusting screws 21 provided on the bottom of an outer tank 20 made of a corrosion-resistant resin such as fluororesin or polyvinyl chloride (PVC). As shown in FIG. 2, the level adjusting screw 21 has an outer screw 211, an inner screw 212 screwed into a screw hole formed in the center of the outer screw 211, and a rotatable center of the outer screw 211. And a support member 213 which is inserted into A screw groove is also formed on the outer periphery of the outer screw 211, and is screwed into a screw hole formed on the bottom surface of the outer tank 20.

In order to set the level of the inner tank 10 by the level adjusting screw 21, first, the outer screw 211 is rotated to set the height of the tip of the support member 213 to be substantially equal, and then the processing tank 10 is mounted. This can be achieved by placing the apparatus and checking the level of the upper edge portion 12 of the inner tank 10 with a leveler or the like and rotating the inner screw 212 to make fine adjustment. As a result, the levels of the upper edges 12 of the four sides of the inner tank 10 become the same, and the processing liquid L overflows from the upper edge 12 uniformly, so that the processing liquid L circulates uniformly in the inner tank 10. This makes it possible to make the surface treatment of the substrate uniform.

Instead of placing the inner tank 10 on the level adjusting screw 21, the outer tank 20 is adjusted via an adjusting mechanism such as a screw.
A configuration in which the level of the upper edge portion 12 is adjusted by lowering it further may be adopted.

A plurality of substrates W are held in the inner tank 10 at equal intervals by a substrate holding holder (not shown) in an upright state. The processing liquid ejection pipe 30 is horizontally laid horizontally through the side surface of the inner tank 10, and is welded and fixed in a liquid-tight manner at the penetrating portion. One end 31 of the processing liquid ejection pipe 30 is closed, and the other end 32 projects from the side surface of the inner tank 10 and is connected to a processing liquid circulation device 50 (FIG. 4) described later.

A plurality of processing liquid ejection holes 30a are provided in a row on the side surface of the processing liquid ejection pipe 30 at a pitch equal to the arrangement interval of the substrates W, and the processing liquid L is uniformly spread on the surface of the substrate W. It is ejected in the direction of the arrow in FIG. 2 so as to flow. The jetted processing liquid L flows in the inner tank 10 and eventually the upper edge 12
The liquid overflows from the tank and is collected in the processing liquid collecting tank 11. The processing liquid recovery tank 11 is provided with a drainage port 11a, and the processing liquid L discharged from the drainage port 11a is supplied to the processing liquid circulation device 50.
After being purified in (FIG. 4), it is supplied again into the inner tank 10 from the processing liquid ejection pipe 30.

A cover member 22 is provided above the inner periphery of the outer tank 20.
Is attached. The cover member 22 includes a horizontal portion 22.
1 and a vertical portion 222, and the lower end portion of the vertical portion 222 overflows and is stored in the processing liquid recovery tank 11 without contacting the inner tank 10 as shown in FIGS. 1 and 2. It is immersed in the processing liquid L.

An inert gas ejection pipe 40 is horizontally provided as an inert gas ejecting means at an intersection of the horizontal portion 221 and the vertical portion 222 on one side of the inner periphery of the cover member 22 and faces the same. The height of the cover member 22 on the side is slightly increased, and a first exhaust port 223 is provided below the vertical portion 222.

As shown in FIG. 3, the cover member 22 is integrally formed of a corrosion-resistant resin such as a fluorine resin, and is mounted on a support member 201 attached to the inner peripheral portion of the outer tank 20. Therefore, not only during assembly, but also
It can be easily attached and detached at the time of cleaning the outer tank 20 and the outer tub 20, and at the time of maintenance, and can be easily installed in an existing substrate processing apparatus.

The inert gas ejection pipe 40 is provided with a plurality of ejection holes 40a on a row at a predetermined pitch, and is supplied from an inert gas supply device 80 (FIG. 4) described later to this inert gas ejection pipe 40. By supplying the inert gas, the inert gas is ejected from the ejection holes 40a so as to cover the entire surface of the processing liquid L substantially in parallel with the liquid surface thereof, and the inert gas is injected from the first exhaust port 223 to the side surface of the outer tank 20. The air is exhausted to the outside by an exhaust device 70 (FIG. 4) via a second exhaust port 23 provided in the section. Further, by changing the rotation angle of the damper 24 provided in the second exhaust port 23, the above exhaust amount can be adjusted.

FIG. 4 is a block diagram showing the overall configuration of the substrate processing apparatus according to this embodiment. Treatment liquid recovery tank 11
Is connected to the processing liquid circulation device 50.
The treatment liquid circulation device 50 includes a circulation pump 51 and a filter 52 for filtering the treatment liquid L sent from the circulation pump 51.
Is provided. The processing liquid L which is sent by the circulation pump 51 and purified by removing foreign matter such as heavy metal fragments and dust generated during the surface treatment by the filter 52 is sent to the processing liquid ejection pipe 30. As the circulating pump 51, a bellows-type pump is usually used, and a bellows made of a corrosion-resistant flexible resin is driven to expand and contract from the outside by a driving mechanism such as a motor or an electromagnet to perform a pump operation. The driving of the circulation pump 51 is managed and controlled by the control device 60 according to the progress of the surface treatment process. In this way, the processing liquid L is circulated and used, so that the maintenance cost can be reduced.

In order for the water seal mechanism to be established at the lower end of the vertical portion 222 of the cover member 22 as described above, it is necessary that the overflowing processing liquid L be stored in the processing liquid recovery tank 11 in an appropriate amount. Therefore, the circulation flow rate of the processing liquid circulation device 50 is controlled by the control device 60 within such a range.

On the other hand, the second exhaust port 23 on the side of the outer tank 20
Is connected to the exhaust device 70. The exhaust device 70 rotates the fan 71 with the motor 72 to forcibly exhaust the gas, and the gas processing device 73 processes the gas harmful to the human body generated during the substrate processing, converts the gas into harmless gas, and discharges the gas to the atmosphere. . The rotation angle of the damper 24 and the operation of the motor 72 are controlled by the control device 60, so that the displacement is appropriately maintained. As the exhaust device 70, a device installed as a facility in a manufacturing factory for semiconductors or the like can be used.

An inert gas supply device 80 is connected to the inert gas ejection pipe 40. This inert gas supply device 8
Numeral 0 is constituted by connecting an inert gas cylinder 81, a regulator 82, a flow control valve 83, a flow meter 84, and a filter 85 in series. As the inert gas G, an inexpensive nitrogen gas is generally used. .

The regulator 82 controls the amount of gas supplied from the inert gas cylinder 81 under the control of the control device 60, and the flow control valve 83 regulates the supply of an excessive amount of gas. In addition, the flow meter 84 allows the operator to constantly check the flow rate. Flow meter 8
The inert gas G that has passed through the filter 4 is subjected to removal of foreign matter such as dust by a filter 85 and then the inert gas ejection pipe 40.
From the processing liquid L in a direction substantially parallel to the liquid surface.

The control unit 60 determines whether an appropriate amount of the inert gas G is present, based on the presence / absence of the upflow of the processing liquid L, the amount of downflow of the clean air from above the processing tank 10, and the operation state of the exhaust device 70. The regulator 82 is controlled so that the inert gas is ejected from the inert gas ejection pipe 40 and a uniform and dense atmosphere of the inert gas is formed on the surface of the processing liquid L. Since the influence of the exhaust amount by the exhaust device 70 is the largest in the atmosphere formation of the second exhaust port 2, the second exhaust port 2
3, an exhaust pressure detector 231 is provided, and this output signal is provided to the control device 60 to perform feedback control. Thereby, the usage amount of the inert gas G can be maintained as necessary and to a minimum.

FIG. 5 shows clean air C in this embodiment.
It is a figure which shows typically the flow of gas when downflow is carried out. Jet hole 40 of inert gas jet pipe 40
The inert gas G ejected from a in a direction substantially parallel to the liquid surface of the treatment liquid L is effectively treated without being scattered to the sides by the action of the cover member 22 having the water seal mechanism as described above. The liquid L flows over the liquid surface, and is sucked as it is from the first exhaust port 223 and the second exhaust port 2
Exhausted via 3. On the other hand, the clean air C blown downward from above the processing tank 10 contains the processing liquid L.
Of the cover member 22 along the flow of the inert gas G without flowing downward through the flow of the inert gas G,
Is exhausted from the second exhaust port 23. As a result, the atmosphere and the clean air C are exhausted almost without contacting the liquid surface of the processing liquid L, and an increase in dissolved oxygen in the processing liquid L can be prevented. As described above, the air curtain by the inert gas G not only blocks the contact between the atmosphere and the processing liquid L to prevent an increase in dissolved oxygen, but also causes mist generated during substrate processing by the chemical liquid to the outside. Since it also has a function of preventing scattering, it also has a secondary effect that the downflow amount and the exhaust amount can be suppressed lower than before.

FIG. 6 is a side sectional view corresponding to FIG. 1 of another embodiment of the substrate processing apparatus according to the present invention.

In this embodiment, the present invention is applied to a substrate processing apparatus of a type in which a processing liquid used for processing a substrate is discarded into a waste liquid tank without being reused.

As described above, in order for the water seal mechanism to be established at the lower end of the vertical portion 222 of the cover member 22, it is necessary to store an appropriate amount of the overflowing processing liquid L in the processing liquid recovery tank 11. When the processing liquid recovery tank 11 is simply connected to the waste liquid tank, the processing liquid L flows out to the waste liquid tank without being stored in the processing liquid recovery tank 11. For this reason, in this embodiment, by providing the processing liquid recovery tank 11 with the overflow section 11b and providing the second recovery tank 11c outside the overflow section 11b, the processing overflowing from the upper edge 12 of the inner tank 10 is performed. The liquid L is temporarily stored in the processing liquid recovery tank 11 by an amount defined by the height of the overflow portion 11b,
Further, the processing liquid L overflowing from the overflow section 11b to the second recovery tank 11c is discharged from a waste liquid port 11d to a waste liquid tank (not shown).

In the above-described embodiment, a plurality of ejection holes 40a are provided in a row in the inert gas ejection pipe 40, but instead of the ejection holes 40a, the side surface longitudinal direction of the inert gas ejection pipe 40 is used. One slit may be formed, and an inert gas may be ejected from the slit, or a plurality of nozzles may be arranged in the same direction. In addition, the jetting direction of the inert gas is set to a direction substantially parallel to the liquid surface of the processing liquid L, but may be jetted at a predetermined angle with respect to the liquid surface. In this case, it is preferable to make the height of the vertical portion 222 of the cover member higher because the inert gas is easily dissipated.

In the configuration shown in FIG. 4, an exhaust pressure detector 231 is provided at the second exhaust port 23, and this output signal is given to the control device 60 to control the inert gas supply device 80.
Although the ejection amount of the inert gas G is automatically controlled, in some cases, such automatic control by the control device 60 is not necessarily required. For example, other processing conditions are sufficiently controlled and are always constant. In some cases,
In some cases, manual control is sufficient.

The cover member 22 is of an integral type so that it can be easily removed. However, the cover member 22 may be separated and removed for each side, and may be made of PVC, PE, SUS or the like in addition to the above-mentioned fluororesin. And so on. Regardless of the nitrogen gas, other gases suitable for the substrate processing may be used as the inert gas.

Also, among the constituent elements of the above-described substrate processing apparatus, those whose material is not specified, the processing liquid L
It is needless to say that a material having anticorrosive properties is used at least on the contact surface.

As the filter 52 and the filter 85, in addition to a filter using a membrane membrane, a filter purifying by electric or other means may be used in some cases.

The present invention relates to a so-called carrierless type substrate processing apparatus in which a substrate W is taken out of a substrate transfer container (carrier), and only the substrate W is processed by holding the substrate W in a substrate holding holder in an inner tank 10. The present invention is not limited thereto, and the present invention can also be applied to a carrier type in which the carrier is immersed in the inner tank 10 while being placed on the carrier for processing.

[0045]

As described above, according to the first aspect of the present invention, since the periphery of the upper edge of the processing tank is surrounded by the cover member, the inert gas blown out from the jetting means of the inert gas supply means. The gas is supplied only to the processing liquid surface without being dissipated, and is exhausted by the exhaust means. Since the lower end of the cover member is disposed in a state where it is immersed in the processing liquid stored in the processing liquid recovery tank formed around the processing tank, a water seal mechanism is formed at this portion, and the inclination of the processing tank is reduced. In addition, while facilitating the adjustment, the dissipation of the inert gas in the relevant portion can be reliably prevented. As a result, the atmosphere of the inert gas can be efficiently formed on the surface of the processing liquid with a small amount of inert gas, and the contact between the atmosphere and the surface of the processing liquid can be completely shut off. Inconvenience such as dissolution in the substrate does not occur, and substrate processing can be performed accurately at low cost.

According to the second aspect of the present invention, the exhaust amount detected by the exhaust unit is detected by the exhaust amount detecting unit, and the operation of the ejection amount adjusting unit is feedback-controlled by the control unit. Can be controlled to an appropriate amount, the use of useless inert gas is regulated, and the amount of use can be minimized.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a processing tank part of a substrate processing apparatus according to one embodiment of the present invention.

FIG. 2 is a front sectional view taken along line AA of FIG. 1;

FIG. 3 is a perspective view showing an appearance of an outer tub in FIG.

FIG. 4 is a schematic diagram illustrating an overall configuration of the substrate processing apparatus of FIG. 1;

FIG. 5 is a diagram showing a state of gas flow when there is a downflow in the embodiment of FIG. 1;

FIG. 6 shows another embodiment of the substrate processing apparatus according to the present invention.
FIG.

FIG. 7 is a front sectional view of a processing tank part of a conventional substrate processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inner tank 11 Processing liquid collection tank 20 Outer tank 21 Level adjusting screw 22 Cover member 30 Processing liquid ejection pipe 40 Inert gas ejection pipe 50 Processing liquid circulation device 60 Control device 70 Exhaust device 80 Inert gas supply device 81 Inert gas cylinder 82 Regulator 231 Exhaust pressure detector

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumihiro Ikeda 2426-1, Minogami-ku, Kinokawahara, Yasu-cho, Yasu-gun, Shiga Prefecture Inside the Yasu Works of Dainippon Screen Mfg. Co., Ltd. 9773 (JP, A) Hikaru Hei 3-71627 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/304 642 B08B 3/04

Claims (2)

(57) [Claims] 1. A substrate processing apparatus for supplying a processing liquid into a processing tank in which a substrate is held and causing the processing liquid to overflow to perform a surface treatment of the substrate. An inert gas supply unit that blows a gas, an exhaust unit that exhausts the inert gas through an exhaust port provided to face the ejection unit, and a diffusion of the inert gas that is sprayed on the processing liquid surface. A cover member provided around the upper edge of the processing tank, and a processing liquid recovery tank for collecting the overflowed processing liquid is provided on the outer periphery of the processing tank, A substrate processing apparatus, wherein a lower end of the cover member is immersed in a processing liquid stored in the processing liquid recovery tank. 2. The method according to claim 1, wherein the inert gas supply unit includes: an ejection amount adjustment unit that controls an ejection amount of the inert gas; an exhaust amount detection unit that detects an exhaust amount by the exhaust unit; Control means for controlling the operation of the ejection amount adjustment means by the detection signal of, the supply amount of the inert gas by the inert gas supply means,
2. The substrate processing apparatus according to claim 1, wherein an appropriate amount is controlled according to an exhaust amount of the exhaust unit.