JP2813197B2 - Processing liquid supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a processing liquid supply device.

(Prior Art) Generally, in a semiconductor manufacturing process, a fine circuit pattern is transferred onto a substrate such as a semiconductor wafer by a photolithographic technique using a photoresist. That is, after applying a photoresist film on the surface of a semiconductor wafer or the like by a resist coating device that applies a photoresist by so-called spin coating, a baking device that performs a heat treatment, and the like, and performing exposure through a mask of a predetermined pattern, Development is performed by a developing device to form a predetermined resist pattern, and using this resist pattern, a predetermined circuit pattern is formed by, for example, etching, thin film formation, or the like.

In the above-described semiconductor manufacturing process, a developing device that develops a photoresist applied to a surface of a substrate such as a semiconductor wafer is conventionally configured as follows, for example.

That is, the developing device is provided with a chuck for holding the semiconductor wafer by, for example, vacuum suction, and a drive mechanism is connected to the chuck so that the wafer held on the chuck can be rotated. Above the chuck, a nozzle for supplying a processing liquid such as a predetermined developing liquid or rinsing liquid is provided. The nozzle is connected to a processing liquid supply source, for example, a tank via an opening / closing valve or the like, and the processing liquid can be supplied to the wafer surface through the nozzle by pressurizing the tongue with, for example, N ₂ (nitrogen). It has a structure. Then, a processing solution such as a predetermined developing solution and a rinsing solution is supplied to the surface of the wafer held on the chuck from the nozzle to perform a predetermined developing process.
The drive mechanism rotates the wafer to remove (dry) the developing solution, the rinsing solution, and the like. Such a developing technique is described in, for example, JP-A-57-5046 and JP-A-62-66.
No. 440, etc.

(Problems to be Solved by the Invention) However, according to the above-described conventional technique, when the developing solution is supplied from the tank to the wafer surface through the nozzle, the inside of the tank is pressurized by, for example, N ₂ , and the developing solution is Liquid is being sent. When this pressurization is performed for a long time, N ₂ dissolves in the developer and becomes fine bubbles and is sent together with the developer. Then, even if the opening / closing valve is closed after the development processing is completed, dripping occurs from the nozzle tip due to the air bubbles mixed into the developing solution, and if this is dropped on the wafer surface, adverse effects such as uneven development are caused. Will be given. Also, if bubbles are mixed in the developing solution, even if the developing solution is supplied to the wafer surface during the developing process, the developing speed of the portion where the bubbles are present is reduced, which also has an adverse effect such as uneven development. There was a problem that occurred. Further, when the number of the bubbles is large, it is necessary to periodically perform a bubble removing operation from the tank.

Further, the incorporation of the bubbles also occurs when replenishing the developing solution into the tank. For this reason, when replenishing the developing solution, temporarily suspend the operation of the device, remove the tank, replace it with a new tank, set it up, start the operation after removing bubbles in the tank, and start the operation of the device. The work involved in making it work was very time-consuming.

Further, such a technique for removing bubbles is disclosed, for example, in Japanese Patent Application Laid-Open No. 61-174719, by forming an obstacle in the nozzle tube and a hole in the nozzle tube wall, and removing bubbles in the developer. There is a technique in which the crushed particles hit an obstacle in the nozzle tube and are removed from a hole in the nozzle tube wall. However, in this technique, the developer also leaks out of the hole in the nozzle tube wall together with the bubbles. Since this developer is flammable, it is extremely dangerous to leak to the outside, and there is a risk of fire of the apparatus, which has made implementation difficult.

The present invention has been made in view of the above points, and it is possible to prevent a processing solution containing air bubbles from being sent into a processing chamber and further to eliminate a troublesome operation such as bubble removal. It is intended to provide a liquid supply device.

(Means for Solving the Problems) According to the present invention, first, a tank capable of storing a processing liquid, a pump for supplying the processing liquid to a processing chamber, and a processing liquid in the tank are supplied to the processing chamber. And a supply means for introducing an explosion-proof purge gas into the tank. In this processing liquid supply device, a filter for trapping bubbles may be provided in the tank.

(Function) According to the present invention, since the processing liquid in the tank is sent by the power of the pump instead of the conventional method of pressurizing the inside of the tank, no bubbles are generated due to the pressurization and bubbles are mixed. Unprocessed processing liquid can be sent into the processing chamber.

In the present invention, the pump used for sending liquid may be a so-called positive displacement pump such as a bellows pump or a diaphragm pump. Preferably, a diaphragm pump is used. The diaphragm pump has a low dusting property and a high discharge pressure, so that a large volume of processing liquid can be sent.

On the other hand, when a bellows type pump, a diaphragm pump, or the like is stopped in the middle of the operation in which the processing liquid remains in the pump, the supply of the processing liquid when it is driven next becomes unstable. Therefore, a switching means such as a three-way valve is provided downstream of the pump in the liquid feed pipe, and after supplying a predetermined amount of the processing liquid into the processing chamber, the three-way valve is switched to allow the processing liquid fed by the pump to flow. It is preferable to take out from the liquid feed pipe without supplying the liquid into the processing chamber. Then, a stable and desired amount of the processing liquid can always be supplied into the processing chamber. If a pipe for returning the processing liquid taken out of the liquid feed pipe back into the tank is connected to the three-way valve, the waste of the processing liquid can be reduced, which is economical.

Further, for example, a filter may be provided in the tank in order to trap air bubbles.

When the processing liquid in the tank is sucked and fed by the power of the pump as in the present invention, there is a concern that the pressure in the tank becomes negative due to the liquid feeding. Therefore, it is preferable to provide a discharge pipe to keep the pressure in the tank constant. When the processing liquid is a flammable liquid such as a developing liquid, it is preferable to provide safety by providing a supply pipe for introducing an explosion-proof purge gas in the tank.

(Embodiment) An embodiment in which the apparatus of the present invention is applied to a developing process of a semiconductor wafer will be described below with reference to the drawings.

 First, the configuration of the developing device will be described.

The developing device (1) is a device for performing a developing process after exposing a pattern on a photoresist applied on a substrate to be processed, for example, a semiconductor wafer (2), and as shown in FIG. It comprises a rotary processing device (3) for rotating 2) and a processing liquid supply device (4) for supplying a processing liquid, for example, a developing liquid, to the surface of the wafer (2).

The rotation processing device (3) is provided with a chuck (5) made of resin, for example, Delrin (trade name), which can hold, for example, suck and hold the back surface of the wafer (2). A drive mechanism, for example, a spin motor (6) is connected to the chuck (5), and the rotation can be controlled at a predetermined acceleration and rotation speed. Further, the processing liquid is supplied to the surface of the wafer (2), and the wafer (2) is held by the chuck (5) so as to collect the processing liquid scattered from the wafer (2) when rotating the wafer (2). A processing chamber (8) is formed by disposing a cup (7) around 2). The cup (7) has a U-shaped cross section with a bottomed cylindrical shape and an open top, and a portion of the side wall of the cup (7) that intersects with the extended surface of the surface of the wafer (2) has an angle A. (A ≠
90 °). By inclining the side wall of the cup (7), the processing liquid scattered from the surface of the wafer (2) hits the inclined portion and is guided in a direction other than the surface of the wafer (2), for example, in the downward direction. To prevent bouncing back. At the bottom of the cup (7), a drain pipe (9) for draining a developing solution, a rinsing liquid, etc., and an exhaust inside the processing chamber (8) are provided outward from the center. An exhaust pipe (10) is provided. In this case,
An annular separating wall (11) is provided at the bottom of the cup (7) so as to prevent the drainage from entering the exhaust pipe (10), and the exhaust pipe (10) is provided inside the separating wall (11). 10) is located. Further, the bottom surface of the cup (7) has a position where the drain pipe (9) is provided at the lowest position so that the drain liquid collects in the drain pipe (9), and has a gradually gentle slope. .

As shown in FIG. 2, the processing liquid supply device (4) is provided with a nozzle (12) for supplying a processing liquid, for example, a developing liquid, to the surface of the wafer (2). The nozzle (12) is arranged above the rotation center of the wafer (2), and is provided so that the developing solution flows out from the center of the wafer (2). This nozzle (12)
Connected to the pump (14) via the
Is a tank (1) that is a processing liquid storage tank via a liquid feed pipe (15).
6). This allows the nozzle (12),
The pump (14) and tank (16) are connected to the liquid feed pipe (13) (1
5) are connected in series. The above pump (1
4) may be a bellows type pump, but it is preferable to use a diaphragm pump. Since the diaphragm pump has low dusting property and high discharge pressure, it has an effect that a large flow rate of the developer can be fed. A pipe (17) to which driving air is supplied is connected to the pump (14), and the supply of the driving air is controlled by an open / close valve (18) interposed in the pipe (17). The pump (14) has a structure capable of controlling the amount of the developer supplied, that is, the amount of the developer supplied to the wafer (2). Further, a silencer (19) is provided on the exhaust side of the pump (14) as a means for preventing noise when exhausting the driving air from the pump (14) from the pump (14). The tank (16) is a container made of Teflon (trade name) having a volume of, for example, 5 l, and has a structure in which a processing liquid, for example, a developer (20) is stored in the tank (16). The stored developer (2
In order to supply (0) to the wafer (2) by the pump (14), a liquid feed pipe (15) connecting the tank (16) and the pump (14) is connected to the bottom of the tank (16). Further, a supply pipe (21) for supplying the developing solution (20) into the tank (16) is provided through an upper portion of the tank (16). At this time, when the developer (20) is supplied into the tank (16), for example, the tip of the supply pipe (21) is extended to the vicinity of the bottom of the tank (16), so that bubbles due to the impact of the liquid are formed. Is suppressed. An opening and closing valve (23) that is opened and closed by a control unit (22) is interposed in such a supply pipe (21). The control unit (22) includes:
Liquid level sensor (24) that detects the amount of developer in the tank (16)
Is connected, and the opening and closing valve (23) is opened and closed according to the liquid amount signal of the liquid amount sensor (24). As the liquid amount sensor (24), it is preferable to use a float sensor that does not cause erroneous detection even if bubbles are contained in the developer (20). The liquid amount sensor (24) is a rod-shaped body extending from the top of the tank (16) in to the vicinity of the bottom, is in its upper full sensor (H _1), empty sensor (L ₁₎ on the lower side is provided , And the amount of liquid is detected.
Further, when the amount of the developer in the tank (16) increases or decreases beyond the full sensor (H ₁ ) and the empty sensor (L ₁ ) due to some abnormality, an alarm is generated to stop the apparatus. full limit sensor of (H ₂₎
And an empty limit sensor (L ₂ ) are disposed at both ends of the rod. Such a liquid level sensor (24)
The control unit (22) controls the opening and closing of the opening and closing valve (23) in response to the liquid amount signal from the controller, thereby enabling automatic supply of the chemical liquid, that is, automatic supply of the developer. Further, the upper portion of the tank (16) purge gas such as nitrogen (N ₂₎ N ₂ supply pipe to be introduced into the tank (16) the gas (25) is connected to the explosion-proof, the flow rate of the N ₂ Adjusting valve (26)
There is interposed the N ₂ supply pipe (25). Further, when the developer (20) supplied into the tank (16) overflows, the developer (20) escapes or overflows.
A discharge pipe (27) is connected to the upper part of the tank (16) in order to prevent the inside of the tank (6) from becoming negative pressure as the developer (20) decreases. Further, a pipe (29) branched from a three-way valve (28) provided downstream of the pump (14) of the liquid feed pipe (13) is connected to the upper part of the tank (16). I have. This allows the pump (14)
By switching the three-way valve (28), the developer can be switched to the direction of the wafer (2) or the direction of the tank (16). A control valve (30) is interposed between the three-way valve (28) and the pump (14), and by controlling this, it is possible to prevent the pulsation of the developer and the generation of bubbles by the pump (14). It has been. In addition, the three-way valve (2
8) An opening / closing valve (31) is provided further downstream, and the ON / OFF of the opening / closing valve (31) allows the developer to flow or stop. The developing device is configured as described above.

Next, the operation of the above-described developing device and a method of supplying the processing liquid to the surface of the semiconductor wafer will be described.

First, the wafer (2) is transferred by a transfer means such as a transfer arm or a belt transfer and set on the chuck (5). Then, the wafer (2) is suction-held from the back surface by a vacuum suction mechanism (not shown) provided in the chuck (5). At this time, positioning is performed in advance so that the rotation center of the chuck (5) and the rotation center of the wafer (2) match. Then, the pump (14) is driven to drop a predetermined amount of the developer (20) in the tank (16) from the nozzle (12) onto the surface of the wafer (2). To supply the developer (20), first open the on-off valve (18) and open the pipe (1).
Supply air from 7) to the pump (14). This allows
By driving the pump (14), the developer (20) in the tank (16) is pushed out toward the three-way valve (28). At the same time that the open / close valve (18) is opened, the three-way valve (2
8), open / close valves (31) are also opened. As a result, the developer (20) pushed out by the pump (14) is transferred to the liquid feed pipe (13).
Through the nozzle (12) to the surface of the wafer (2). Then, the developer (20) is used for a preset time.
After supplying the developer, the opening / closing valve (31) is closed, and the supply of the developer (20) to the surface of the wafer (2) is stopped. At the same time, the three-way valve (28) is switched, and the developer (20) pushed out by the pump (14) is returned to the tank (16) via the pipe (29). This is because if the pump (14) is stopped halfway, the developer (20)
Because the liquid supply becomes unstable, the developer (20) pushed out before the pump (14) returns to the home position is returned to the tank (16). This prevents supply of a developing solution (20) of a predetermined amount or more to the surface of the wafer (2).

After supplying the developing solution (20) to the wafer (2), the spin motor (6) is driven to rotate the wafer (2) via the chuck (5). Thereby, the wafer (2)
The developing solution (20) on the surface is diffused by centrifugal force, and the scattered developing solution (20) is collected downward along the inner wall of the cup (7) and discharged from the drain pipe (9). When the application of the developing solution to the surface of the wafer (2) is completed, the developing process is performed by rotating the wafer (2) at rest or at a low rotation. After the completion of the development processing, a rinsing liquid is supplied from a rinsing liquid supply mechanism (not shown) to the upper and lower peripheral edges of the wafer (2) to perform cleaning.

As the developer application is repeated, the storage amount of the developer (20) stored in the tank (16) gradually decreases, and the empty amount sensor (L ₁ ) of the liquid amount sensor (24) is eventually detected. I do. The detection data is transmitted to the control unit (22), and the control unit (22) opens the open / close valve (23) to automatically supply the developer (20) into the tank (16). And the full sensor (H ₁ ) of the liquid level sensor (24)
Is detected, the open / close valve (23) is returned to the normal closed state, and the supply of the developer (20) is stopped. At this time, the developer (20) supplied to the tank (16) contains
Some bubbles are mixed. Therefore, this tank (1
By leaving 6) for a while, bubbles in the developer (20) can be removed.

In the above-described embodiment, the paddle type developing device for supplying the developing solution from the nozzle to the wafer surface has been described as an example. However, the present invention is not limited to this. For example, a spray type or a dip type developing device has the same effect. Can be obtained. In addition, the example in which the processing liquid supply device is applied to the developing device has been described, but the present invention can be applied to any device that uses a chemical solution that easily generates bubbles or a device that requires processing at a large flow rate. .

Further, in the above-described embodiment, as a means for removing bubbles contained in the processing solution, a means for removing bubbles in the developing solution by leaving the tank to which the developing solution is automatically supplied for a while is used. The present invention is not limited to this. For example, a similar effect can be obtained by providing a filter for trapping air bubbles in the tank. Further, the same effect can be obtained with an LCD substrate used for a screen display device such as a liquid crystal TV, as well as a substrate to be processed which is not limited to a semiconductor wafer.

As described above, according to this embodiment, by providing a means for removing air bubbles contained in the processing liquid and a pump for supplying the processing liquid from which the air bubbles have been removed to the processing chamber, the processing can be performed. The liquid is sent to the pump with the air bubbles mixed in the liquid removed. Furthermore, since the processing liquid is sent by the pump instead of the pressing force, no bubbles are generated due to the pressurization.
A processing solution containing no air bubbles can be sent into the processing chamber. Thereby, the trouble of removing bubbles can be omitted.

Further, since the supply and discharge of the processing liquid are automatically executed, and the trapping and generation of bubbles are prevented, there is no need to periodically remove bubbles and to stop the apparatus.

Further, even when the processing is not performed for a long time, since the processing liquid is not pressurized, the dissolution of gas into the processing liquid can be suppressed, and the dripping from the nozzle can be prevented.

〔The invention's effect〕

As described above, according to the present invention, it is possible to supply a processing liquid containing no air bubbles, so that the reliability of the processing in the processing chamber is high and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a developing device for explaining an embodiment of the apparatus of the present invention, and FIG. 2 is an explanatory diagram of a processing liquid supply device of FIG. DESCRIPTION OF SYMBOLS 1 ... Developing apparatus, 2 ... Wafer 4 ... Treatment liquid supply apparatus, 14 ... Pump 16 ... Tank, 20 ... Development liquid 21 ... Supply pipe, 24 ... Liquid quantity sensor 28 ... Three-way valve, 29 …… Piping

Claims (2)

(57) [Claims] 1. A tank capable of storing a processing liquid, a pump for supplying the processing liquid to a processing chamber, and switching between a state in which the processing liquid in the tank is supplied to the processing chamber and a state in which the processing liquid is returned to the tank. A processing liquid supply device, comprising: a switching means; and a supply pipe for introducing an explosion-proof purge gas into the tank. 2. The processing liquid supply device according to claim 1, wherein a filter for trapping bubbles is provided in the tank.