JPH07105332B2 - Liquid treatment method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid processing method.

(Prior Art) Generally, in a developing process, a photosensitive film formed on the surface of a semiconductor wafer or the like is supplied with a developing solution, and the photosensitive film and the developing solution are reacted for a predetermined time to perform development. An apparatus for supplying a large amount of cleaning liquid to the semiconductor wafer to perform rinsing.

Here, the discharge of the supplied developing solution and cleaning solution is
The developer and cleaning solution discharged from the same drain pipe are toxic by strong alkaline solution, flammable organic solvent, etc. It was

(Problems to be Solved by the Invention) However, in the developing device having the above-described configuration, the developing solution and the cleaning solution are discharged from the same discharging pipe, and the discharging amount becomes large. For this reason, there has been a problem that a large amount of the developing solution and the cleaning solution to be purified later, the purification process takes time, and a large-scale purification device is required. For this reason, Japanese Utility Model Laid-Open No. 61-51732 discloses that the processing tanks are doubled and each processing tank is provided with a dedicated developing solution discharge port and cleaning liquid discharge port. However, there is a problem that the size of the processing tank is increased, and the structure is complicated and the number of processes is increased, so that the throughput is reduced and it is not practical. Further, there is also a problem that mist of the processed developer flows back into the processing chamber from the outlet of the developer or remains and is contained in the processed cleaning liquid, resulting in a decrease in recovery efficiency.

The present invention has been made in consideration of the above-mentioned point. Since the toxic developing solution and the washing water can be separated and discharged, only the toxic developing solution can be easily and safely recovered and a small amount of the developing solution is contained. (EN) Provided is a liquid treatment method capable of easily treating a cleaning liquid with waste water, improving throughput, and downsizing the apparatus.

(Means for Solving the Problem) In order to achieve the above object, the liquid treatment method of the present invention is to rotate the object to be treated at a first rotation speed in a state where the treatment liquid drain pipe is opened, A step of supplying a processing liquid to the object to be processed, a step of supplying the processing liquid to the object to be processed at a second rotation speed lower than the first rotation speed, and thereafter A step of stopping the rotation of the object to be processed for a predetermined time, and after the elapse of the predetermined time, the processing liquid drain pipe is closed and the cleaning liquid drain pipe is opened, and Rotating at a third rotation speed higher than the rotation speed and supplying the cleaning liquid to the object to be processed;
A step of stopping the supply of the cleaning liquid and drying the object to be treated.

In the present invention, it is preferable that at least the treatment liquid is supplied to the object to be treated and the treatment liquid is discharged, and the treatment liquid drain pipe and the cleaning liquid drain pipe are exhausted from different locations.

(Operation) According to the present invention, the treatment liquid is supplied to the object to be treated in a state where the treatment liquid drain pipe is opened, and then the treatment liquid is closed, and the treatment liquid drain pipe is closed. By opening the pipe and supplying the cleaning liquid to the object to be processed, the toxic processing liquid and the cleaning liquid can be separated and drained, and the mist of the processing liquid flows back into the processing chamber after processing or the cleaning liquid drain pipe. Inflow to the side can be prevented.

(Example) Next, an example in which an apparatus embodying the liquid processing method of the present invention is applied to a spin developing apparatus will be described with reference to the drawings.

The developing device (1) is a device for developing and cleaning after exposing a pattern on a photoresist applied on an object to be processed, for example, a semiconductor wafer (2), and as shown in FIG. A supply section (3) for supplying a developing solution or a cleaning solution to the object to be processed, and a processing section (4) for performing processing with the developing solution or the cleaning solution supplied to the object to be processed from the supplying section (3). There is.

The processing section (4) is provided with a chuck (5) containing a vacuum suction mechanism for mounting and fixing a liquid processing body such as a semiconductor wafer (2). This chuck (5)
Is engaged with a spin motor (6) and is rotatable at a desired rotation speed.

As described above, the bottomed cylindrical processing tank is provided so as to surround the semiconductor wafer (2) placed on the chuck (5). This processing tank has an open upper cup (7).
And a lower cup (8) having a U-shaped cross-section continuous with the upper cup (7). The upper cup (7) is provided with a flange (9) at the lower edge of the upper cup (7) toward the upper center so as to guide the developing solution or cleaning solution hitting the side surface downward. Further, on the bottom surface of the lower cup (8), a drain pipe (10) outside the center and an exhaust pipe (11) connecting to an exhaust device (not shown) are connected inside and are provided. A separation wall (12) is provided at a predetermined position so as to be separated into a drainage tank for liquid and an exhaust tank for exhaust. Further, in the lower cup (8), a predetermined exhaust flow path is formed so as to prevent splashing of drainage or the like to the back surface of the semiconductor wafer (2), and exhaust gas or the like flows into the exhaust pipe (11). The inner cup (13) having a predetermined shape is fixed so as not to do so. Further, the bottom surface of the lower cup (8) has a position where the drainage pipe (10) is provided at the lowest position so that drainage collects in the drainage pipe (10) and becomes a gradual slope. Here, the drainage pipe (10) configured to collect the drainage is connected to a switching valve, for example, a solenoid valve (14).
Further, the electromagnetic valve (14) is provided with a developing solution drain pipe (15) for exclusively discharging the processed developing solution, and after the developing solution is discharged to the developing processing solution, the object to be processed, for example, a semiconductor wafer (2). ) Is connected to a cleaning liquid drain pipe (16) for exclusively discharging the cleaning liquid, and together with the drain pipe (10), this solenoid valve (14) is connected in a 3-port state. . The other end of the developer drainage pipe (15) connected to the solenoid valve (14) is connected to the waste liquid recovery part (17) and the other end of the cleaning liquid drainage pipe (16). Is connected to the wastewater treatment device (18).

As described above, in the processing tank, the upper cup (7) and the lower cup (8) can be independently moved up and down by an elevating mechanism (not shown) so that the semiconductor wafer (2) can be carried in and out of the chuck (5). It is said that. The processing unit (4) is configured as described above.

Next, the supply section (3) for supplying the developing solution and the cleaning solution to the processing section (4) will be described.

The supply part (3) is provided with a developer tank (19) storing a developer of, for example, a strong alkaline solution or a flammable organic solvent in order to supply the developer to an object to be processed such as a semiconductor wafer (2). ing. A developing solution supply pipe (21) is provided from the developing solution tank (19) to the developing solution supply unit, for example, a spray unit (20), and one end of the developing solution supply pipe (21) has a developing solution tank (21). It is immersed in 19). An opening / closing valve (22) for controlling the supply / stop of the developing solution and a flow rate controller (23) for adjusting the supply rate of the developing solution are provided at predetermined positions of the developing solution supply pipe (21). In addition, the temperature adjusting mechanism (24) is provided so that the developing solution can be adjusted to a desired temperature. Further, in order to supply a cleaning liquid such as pure water to the semiconductor wafer (2), a pure water source (25) and a cleaning liquid supply pipe (26), which are pure water lines in a factory, for example.
Is connected, and a rinse nozzle (27) is installed at the tip of the cleaning liquid supply pipe (26). An opening / closing valve (28) for controlling the supply / stop of the cleaning liquid and a flow rate controller (29) for adjusting the supply amount of the cleaning liquid are provided at predetermined positions of the cleaning liquid supply pipe (26). Supply is controlled.

The developing device (1) is configured by the supply unit (3) and the processing unit (4) as described above.

Next, the operation and operation of the developing device (1) will be described.

The operation of the developing device (1) operates according to a program stored in advance in the CPU incorporated in the developing device (1). First, the upper cup (7) and the lower cup (8) constituting the processing tank are lowered by an elevating mechanism (not shown) to be in a lower state. Here, an object to be processed, for example, a semiconductor wafer (2) is transferred onto the chuck (5) by a transfer mechanism (not shown) such as a handling arm. The transferred semiconductor wafer (2) is vacuum-sucked by a chuck (5) and
The upper cup (7) and the lower cup (8) are raised to form a processing tank at a predetermined position. Next, the spin motor (6) sprays (supplies) the developing solution from the spray unit (20) toward the semiconductor wafer (2) for 0.3 seconds, for example, while rotating the semiconductor wafer (2) at about 1000 rpm / min. . After that, spraying (supplying) is performed for 3 seconds at a rotation speed of about 30 rpm / min, after which the rotation is stopped and development is performed for a predetermined time, for example 60 seconds. The developer is sprayed by the spray unit (20) by supplying a pressurized gas such as nitrogen to the developer tank (19) so that the developer is opened from the tank (19) and the opening / closing valve (22) is opened. The developer is extruded into the supply pipe (21), the flow rate controller (23) regulates the flow rate of the developer, and the temperature control mechanism (24) controls the temperature to a desired temperature to supply it to the spray unit (20). Do it. Next, after the development time has passed, that is, after the reaction between the photosensitive film formed on the surface of the semiconductor wafer (2), for example, the photoresist and the developing solution is completed, the semiconductor wafer (2) is rotated at high speed. Then, the waste liquid containing the excess developing solution (hereinafter referred to as the processed developing solution) is blown off from the peripheral edge of the wafer (2) by the centrifugal force and hits the side surface of the flange (9) or the lower cup (8) of the upper cup (7) to descend. The processed developer that has flowed in the opposite direction and reached the bottom is guided to the drain pipe (10) because the bottom has a gentle slope. This time,
The drain valve (10) and the developing solution drain tube (15) are brought into a connected state (the developing solution drain tube (15) is opened) by a switching valve, for example, a solenoid valve (14), and the induced toxic The processed developer is collected in the waste liquid collecting section (17) according to the formed flow path. The mist and the like of the processed developer is exhausted from the exhaust pipe (11).

After a lapse of a predetermined time, the open / close valve (28) of the cleaning liquid supply pipe (26) is opened, and the pure water as the cleaning liquid supplied from the pure water source (25) is supplied by the flow controller (29). Is supplied to the semiconductor wafer (2) which is rotating at a high speed from the rinse nozzle (27). Then, pure water is caused to flow on the wafer (2) by the centrifugal force, whereby the developing solution is washed away. Then, a waste liquid containing a large amount of pure water which is a cleaning liquid blown off from the peripheral edge of the semiconductor wafer (2) by a centrifugal force and a small amount of the developing liquid which has been washed away (hereinafter, treated cleaning liquid) is the same as the above-mentioned processed developing liquid. Similarly, it is guided to the drain pipe (10). At this time, the solenoid valve (14) is switched to connect the drainage pipe (10) and the cleaning liquid drainage pipe (16) to each other {the cleaning liquid drainage pipe (16)
Open state}, and a large amount of the above-mentioned treated cleaning liquid guided is flowed to the wastewater treatment device (18) according to a predetermined flow path for treatment. In this case, since the drain valve (10) and the developer drain tube (15) are shut off by switching to the solenoid valve (14), harmful mist of the processed developer flows back into the processing tank. There is no risk that the liquid will flow into the cleaning liquid drain pipe (16). In addition, by constantly exhausting air from the exhaust pipe (11) during processing, the atmosphere of harmful mist of processed developer during development processing does not remain in the processing tank. The mist of the developer does not flow into the cleaning liquid drain pipe (16). The exhaust may be performed at least while the developer is supplied to the semiconductor wafer (2) and the processing is performed.

The cleaning liquid is supplied to the semiconductor wafer (2) at the timing of switching the connection of the drain pipe (10) to the developer drain pipe (15) and the cleaning liquid drain pipe (16) by the solenoid valve (14).
The drain pipe (10) and the developer drain pipe (15) connected immediately before the supplied processed cleaning liquid reaches the solenoid valve (14) from the drain pipe (10), With the solenoid valve (14),
It is desirable to switch the connection between the drainage pipe (10) and the cleaning liquid drainage pipe (16). Next, the supply of the cleaning liquid is stopped and the semiconductor wafer (2) is rotated to dry it. The semiconductor wafer (2) is developed as described above.

As described above, according to the present embodiment, one drain pipe is provided with a switching valve, and the switching valve is used to exclusively discharge the processed developer and the treated cleaning liquid. By providing a connection with the cleaning drain pipe, it is possible to easily and safely collect the processed developer that is toxic and highly dangerous, and the processed cleaning liquid contains only a small amount of the processed developer. The waste water can be easily treated, and the device can be made compact without lowering the throughput.

The present invention is not limited to the above-described embodiments, for example, the supply of the developing solution may be a supply nozzle, not a spray unit, and the object to be processed may be an LCD substrate or the like instead of a semiconductor wafer. The number of revolutions of the semiconductor wafer and the supply amount of the developing solution may be arbitrarily selected as appropriate.
The cleaning liquid is not limited to pure water, and may be any liquid as long as it has a cleaning effect.

Further, the connection switching timing of the drainage pipe, the developer drainage pipe and the cleaning liquid drainage pipe by the switching valve may be set at any timing, for example, it may be switched at the same time as the supply of the cleaning liquid, or the treatment is completed. The cleaning liquid may be discharged to the cleaning liquid drain pipe after being discharged to the developing liquid drain pipe by a certain amount. Further, the switching valve need not be a 3-port connection and may be any. Furthermore, the liquid to be used is not limited to the developing liquid and the cleaning liquid, but may be any liquid as long as it discharges different kinds of liquid from the same drain pipe.

(Effect of the Invention) According to the present invention as described above, the toxic treatment liquid and the cleaning liquid can be separated and drained, and the mist of the treatment liquid or the like flows back into the treatment chamber after treatment or the drainage liquid for the washing liquid. It is possible to prevent the liquid from flowing into the pipe side and improve the throughput.

[Brief description of drawings]

FIG. 1 is a block diagram of a developing device for explaining an embodiment of the present invention. 1 ... Developer, 3 ... Supply part 4 ... Processing part, 8 ... Lower cup 10 ... Drain pipe, 11 ... Exhaust pipe 14 ... Solenoid valve, 15 ... Developer drain pipe 16 ... ... Cleaning liquid drain

Claims (2)

[Claims] 1. A step of rotating an object to be processed at a first rotation speed in a state where a drainage pipe for the processing liquid is opened to supply the processing liquid to the object to be processed, and thereafter, the object to be processed. And a step of supplying the processing liquid to the object to be processed at a second rotation speed lower than the first rotation speed, and thereafter, stopping the rotation of the object to be processed for a predetermined time, and after the predetermined time has elapsed, The treatment liquid drain pipe is closed, the cleaning liquid drain pipe is opened, and the object to be treated is rotated at a third rotation speed higher than the first rotation speed to apply the cleaning liquid to the object. And a step of thereafter stopping the supply of the cleaning liquid and drying the object to be processed, the liquid processing method. 2. The liquid processing method according to claim 1, wherein the processing liquid is supplied to at least the object to be processed and the processing is performed.
A liquid processing method comprising exhausting from a location different from the processing liquid drain pipe and the cleaning liquid drain pipe.