JPH1197333A - Resist waste fluid withdrawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To withdraw automatically resist waste fluid in a waste fluid withdrawal bath outside a clean room, by a method wherein, if a waste fluid amount of a fluid reserving bath reaches a supremum, a waste fluid tube is opened by a switching valve, and the waste fluid in the fluid reserving bath is discharged through the waste fluid tube in a waste fluid withdrawal bath until it reaches a lowest limit in the bath. SOLUTION: A semiconductor wafer 1 is rotated at a high speed and resist is uniformly applied on the semiconductor wafer 1. At this time, after surplus resist (waste fluid) is received by a resist applying cup 2, it is dropped from a waste fluid hole 2A to a fluid reserving bath 3. The waste fluid is reserved in a waste fluid tube 8 with an automatic switching valve 9 first of all, and further the process for a plurality of semiconductor wafers 1 is repeated, so that the waste fluid is gradually reserved in the fluid reserving bath 3. If the waste fluid in the fluid reserving bath 3 is reserved up to a position of a supremum sensor 4, the automatic switching valve 9 is opened, and the waste fluid in the fluid reserving bath 3 is flown to a waste fluid withdrawal bath 7 through the waste fluid tube 8. If the waste fluid in the fluid reserving bath 3 is dropped up to a position of a lowest limit sensor 5, the automatic switching valve 9 is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus for coating a resist on the surface of a semiconductor wafer in a patterning step of semiconductor manufacturing, and more particularly to a resist liquid collecting apparatus for collecting a resist liquid after resist coating.

[0002]

2. Description of the Related Art A conventional resist waste liquid collecting apparatus has a structure as shown in FIG. In FIG. 4, a resist is dropped from a resist dropping device 15 onto a surface of a semiconductor wafer 1 placed on a rotating rod 14 in a resist waste liquid collecting device 11, and then the semiconductor wafer 1 is rotated by the rotating rod 14.
Is rotated at a high speed to apply the resist uniformly on the semiconductor wafer 1. At this time, the excess resist (hereinafter, sometimes simply referred to as waste liquid) is received by the resist coating cup 2, then falls from the waste liquid hole 2 </ b> A into the waste liquid tank 12, and is stored in the waste liquid tank 12.

The waste liquid stored in the waste liquid tank 12 is:
As shown in FIG.
Was replaced with an empty tank, and the waste liquid was transferred to a waste liquid recovery tank 7 outside the clean room and collected.

[0004]

However, in the above-mentioned resist waste liquid collecting apparatus, since it is necessary for an operator to access the apparatus to replace the waste liquid tank 12 during the operation of the apparatus routine, an unmanned unmanned apparatus will be considered in the future. There is a problem that it is impossible to correspond to a clean room. In addition, even now, the waste liquid storage in the device, the waste liquid tank 1
Hazardous work such as taking out the 2 and transporting the waste liquid tank 12 is a burden on the operator, and there is a problem in ensuring the safety of the work. Further, when the waste liquid tank 12 is replaced, the resist coating apparatus 11 must be stopped, which causes a problem that the operation rate of the apparatus is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a resist capable of automatically collecting a resist waste liquid in a waste liquid recovery tank outside a clean room without manual operation. It is to provide a waste liquid collecting device.

[0006]

In order to achieve the above object, a first aspect of the present invention is a resist waste liquid collecting apparatus for collecting excess waste liquid from a resist coating apparatus for performing resist processing on a semiconductor wafer into a waste liquid collecting tank. In the apparatus, a liquid storage tank for temporarily storing the excess waste liquid, a waste liquid tube that communicates with the bottom of the liquid storage tank and allows the internal waste liquid to flow into the waste liquid recovery tank, and a waste liquid tube provided on the opening side of the waste liquid tube is provided. An open / close valve that opens and closes, a sensor unit that detects the amount of waste liquid in the liquid tank, and when the sensor unit detects that the amount of waste liquid in the liquid tank reaches an upper limit, the open / close valve is opened and the waste liquid is opened. A control unit that performs control to close the open / close valve when it is detected that the amount has reached the lower limit.

According to the first aspect of the present invention, excess waste liquid from a resist coating apparatus that performs resist processing on a semiconductor wafer installed in a clean room is temporarily stored in a liquid storage tank, and when the amount of waste liquid in the liquid storage tank reaches an upper limit. The waste liquid tube is opened by the open / close valve, and the waste liquid in the liquid storage tank is discharged through the waste liquid tube to the waste liquid recovery tank installed outside the cree room until the lower limit is reached in the tank, thereby collecting the waste liquid. . Thereafter, similarly, when the waste liquid in the liquid storage tank reaches the upper limit, the waste liquid in the liquid storage tank is automatically collected periodically in the waste liquid recovery tank until the waste liquid reaches the lower limit. At this time, since the open / close valve is attached near the opening of the waste liquid tube on the waste liquid recovery tank side, when the waste liquid in the liquid storage tank reaches the lower limit, the waste liquid tube is filled with the waste liquid, and the open / close valve is opened. This causes the waste tube to close. As a result, a constant amount of waste liquid flows into the waste liquid tube, and the waste liquid tube is always filled with the resist waste liquid, so that the waste liquid does not dry and block the waste liquid tube, and the waste liquid is smoothly drained. And can be collected.

A feature of the second invention is that a flow control valve is provided between the bottom side of the liquid reservoir and the open / close valve side of the waste liquid tube to adjust the flow rate of the waste liquid flowing through the waste liquid tube. It is in.

According to the second aspect, the flow control valve is set so as to flow the used amount of the chemical solution (resist, rinse, etc.) per wafer at the wafer processing interval. Thereby, when the waste liquid in the liquid storage tank reaches the upper limit, the waste liquid per wafer processing flows through the waste liquid tube to the waste liquid recovery tank, and furthermore, only the amount of the waste liquid flowing into the waste liquid recovery tank,
The waste liquid for the next wafer processing is supplied to the liquid storage tank. Therefore, the waste liquid in the liquid storage tank is stable around a little less than the upper limit, and the waste liquid always flows through the waste liquid tube to the waste liquid recovery tank, so that the waste liquid tube is surely clogged by drying of the waste liquid. Is prevented.

According to a third aspect of the present invention, there is provided a resist waste liquid collecting apparatus for collecting excess waste liquid from a resist coating apparatus for performing a resist process on a semiconductor wafer into a waste liquid collecting tank.
A liquid storage tank for temporarily storing the excess waste liquid, a waste liquid tube communicating with a bottom portion of the liquid storage tank and allowing the internal waste liquid to flow to a plurality of waste liquid recovery tanks, and a branch branched into a plurality of ends; An opening / closing valve provided for opening and closing a waste liquid tube, a sensor unit for detecting a waste liquid amount in the liquid reservoir, and a branch part of the waste liquid tube, wherein waste liquid is provided to any one of the plurality of waste liquid recovery tanks. A switching valve for switching the flow path of the waste liquid tube to guide the waste liquid, a recovery tank sensor provided in each of the plurality of waste liquid recovery tanks for detecting the amount of waste liquid inside, and an upper limit of the amount of waste liquid in the liquid storage tank by the sensor unit. When it is detected that the waste liquid amount has reached the lower limit, the open / close valve is opened, and when it is detected that the waste liquid amount has reached the lower limit,
A control unit for performing control to close the open / close valve and to control the switching valve to switch the waste liquid in the waste liquid tube to another waste liquid recovery tank when the recovery tank sensor detects the upper limit of the waste liquid. That is.

According to the third aspect of the invention, when one waste liquid collecting tank is full of waste liquid, the control unit detects this when the waste liquid collecting tank is full, and the switching valve switches the waste liquid to another empty waste liquid collecting tank. So that it flows to As a result, there is almost no possibility that the control unit stops the operation of the resist coating device due to a trouble at the time of replacing the waste liquid collecting tank,
The resist processing of the semiconductor wafer can be performed without interruption.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a first embodiment of a resist waste liquid collecting apparatus according to the present invention. A rotating rod 14 is arranged at the center of the circular resist coating cup 2 having a circular through hole at the center. Rotating rod 14
The semiconductor wafer 1 is placed on the substrate, and a resist dropping device 15 is disposed at a central portion above the semiconductor wafer 1. A waste liquid hole 2A is provided on the bottom surface of the resist coating cup 2, and the waste liquid hole 2A is connected to a liquid storage tank 3 installed immediately below.

A branch pipe 31 is provided at the outer periphery of the liquid reservoir tank 3 and communicates with the tank vertically. A lower limit sensor 5 is mounted below the branch pipe 31, and an upper limit sensor 4 is mounted above the branch pipe 31. A limit sensor 6 is mounted on the top. The detection signals from the upper limit sensor 4, the lower limit sensor 5, and the limit sensor 6 are input to the control unit 16.

A waste liquid tube 8 extends from the liquid storage tank 3 through a floor 20 of the clean room to a waste liquid recovery tank 7 installed on the lower floor outside the clean room. A Valp 9 is equipped. The automatic opening / closing valve 9 is controlled by the control unit 16 to open and close. Above the waste liquid recovery tank 7, a liquid amount sensor 13 for detecting the amount of waste liquid inside is attached. The resist waste liquid collecting device is attached to the resist coating device 11 in the clean room, and includes a liquid storage tank 3, an upper limit sensor 4, a lower limit sensor 5, a waste liquid tube 8, an automatic opening / closing valve 9, a waste liquid collecting tank 7, and a liquid amount sensor 13. Have.

Next, the operation of this embodiment will be described. The resist dropping device 1 is mounted on the surface of the semiconductor wafer 1 mounted on the rotating rod 14 in the resist waste liquid collecting device 11.
After the resist is dropped from 5, the semiconductor wafer 1 is rotated at a high speed by the rotating rod 14, and the resist is uniformly applied on the semiconductor wafer 1. At this time, the surplus resist (waste liquid) is received by the resist coating cup 2 and then falls from the waste liquid hole 2A into the liquid storage tank 3.

Initially, the automatic opening / closing valve 9 is closed, so that the waste liquid is accumulated in the waste liquid tube 8 with the automatic opening / closing valve 9 at the top, and the processing for a plurality of semiconductor wafers 1 is repeated, so that the liquid storage tank 3 is gradually removed. Accumulate inside.

When the waste liquid in the liquid storage tank 3 is collected up to the position of the upper limit sensor 4, the upper limit sensor 4 detects this and notifies the control unit 16. When the control unit 16 knows that the waste liquid has accumulated in the liquid storage tank 3 up to the position of the upper limit sensor 4, the control unit 16 opens the automatic opening / closing valve 9 and discharges the waste liquid in the liquid storage tank 3 through the waste liquid tube 8 to the waste liquid collection tank 7. Pour into

As a result, when the waste liquid in the liquid storage tank 3 drops to the position of the lower limit sensor 5, the lower limit sensor 5 detects this and notifies the control unit 16. When the control unit 16 knows that the waste liquid has dropped to the position of the lower limit sensor 5, it closes the automatic opening / closing valve 9. At this time, since the waste liquid is always filled in the waste liquid tube 8, the waste liquid does not come into contact with air, and therefore, the dried waste liquid does not adhere to the inner wall of the waste liquid tube 8, so that the tube 8 is clogged with the dried waste liquid. Nothing.

Thereafter, the processing of the semiconductor wafer 1 proceeds,
When the waste liquid in the liquid storage tank 3 rises again and collects up to the position of the upper limit sensor 4, the above-described control is performed again. Therefore,
By repeating the above control, the waste liquid is automatically collected in the waste liquid recovery tank 7 outside the clean room while preventing the drying of the waste liquid by always filling the waste liquid tube 8 with the waste liquid.

When the waste liquid collecting tank 7 is full of waste liquid, the liquid amount sensor 13 detects this and notifies the control unit 16. close. Thereafter, the waste liquid recovery tank 7 outside the clean room is replaced with an empty waste liquid recovery tank 7. Here, when the waste liquid collecting tank 7 is full of the waste liquid, the control unit 16 may notify the worker by a buzzer or the like.

At this time, the volume of the liquid storage tank 3 is changed to the waste liquid recovery tank 7.
Since the amount of waste liquid generated within the time required for the replacement is secured, the resist coating apparatus 11 can continue to operate during this time. However, if a trouble such as spending a predetermined time or more in replacing the waste liquid recovery tank 7 occurs,
When the waste liquid rises and accumulates to the position of the limit sensor 6, the limit sensor 6 notifies the control unit 16 of this. As a result, the control unit 16 stops the resist coating operation of the resist coating apparatus 11 on the semiconductor wafer 1.

According to the present embodiment, the resist waste liquid after application of the semiconductor wafer 1 is temporarily stored in the liquid storage tank 3, and when the waste liquid in the liquid storage tank 3 reaches the upper limit amount, the automatic opening / closing valve 9 is opened. Is opened, and the waste liquid flows through the waste liquid tube 8 to the waste liquid recovery tank 7 until the waste liquid in the liquid storage tank 3 reaches the lower limit. When the waste liquid reaches the lower limit, the automatic opening / closing valve 9 is closed, and the control of storing the waste liquid in the liquid storage tank 3 is repeated, so that the resist waste liquid after application of the semiconductor wafer 1 is automatically discharged to the waste liquid outside the clean room without human intervention. It can be collected in the collection tank 7 and can be used in an unmanned clean room.

At this time, since the waste liquid tube 8 is always filled with the waste liquid, the waste liquid tube 8 does not become clogged with the dried solidified waste liquid, and the above-mentioned waste liquid can be collected smoothly.

Although FIG. 1 shows one resist liquid collecting device attached to one resist coating device 11 for one waste liquid collecting tank 7, a plurality of resist coating devices are provided. The same effect can be obtained even if the waste liquids of the plurality of resist waste liquid recovery apparatuses of the apparatus 11 are collectively collected by one waste liquid recovery tank 7.

FIG. 2 is a schematic view showing a second embodiment of the resist waste liquid collecting apparatus according to the present invention. Liquid storage tank 3 of this example
A manual flow rate control valve 10 is inserted into the waste liquid tube 8 connected to the apparatus, and an automatic opening / closing valve 9 is provided below the manual flow rate control valve. Other configurations are the same as those of the first embodiment shown in FIG.

Next, the operation of this embodiment will be described. First, the flow rate control valve 10 is adjusted so that the amount of chemical solution (resist, rinsing, etc.) used per wafer flows into the waste tube 8 at wafer processing intervals. Thereafter, when the automatic opening / closing valve 9 is closed and the resist is applied on the semiconductor wafer 1, the waste liquid is accumulated in the waste liquid tube 8 with the automatic opening / closing valve 9 at the top, and the processing on a plurality of semiconductor wafers is repeated. Then, the liquid gradually accumulates in the liquid reservoir 3. When the waste liquid in the liquid storage tank 3 is collected up to the position of the upper limit sensor 4, the automatic opening / closing valve 9 opens,
The waste liquid flows continuously through the waste liquid tube 8 into the waste liquid recovery tank 7 at the flow rate set by the flow rate adjustment valve 10.

Therefore, at the wafer processing interval, the amount of waste liquid flowing from the resist coating cup 2 into the liquid storage tank 3 and the amount of waste liquid flowing out of the liquid storage tank 3 into the waste liquid recovery tank 7 are the same due to the action of the flow control valve 10 described above. Therefore, the amount of waste liquid in the liquid storage tank 3 and the waste liquid tube 8 is almost constant at all times.
The waste liquid always flows through the waste liquid tube 8 and is discharged to the waste liquid recovery tank 7. Thereby, the waste liquid in the waste liquid tube 8 does not come into contact with air, and the drying and fixation of the waste liquid is eliminated, so that the waste liquid in the waste liquid tube 8 can be prevented from clogging.

When the wafer processing interval becomes longer due to an external factor such as a lot wait, the amount of waste liquid in the liquid storage tank 3 decreases, and when the liquid lowers to the position of the lower limit sensor 5, the automatic opening / closing valve 9 closes and the liquid storage tank 3 is closed. Prevent emptying. With these functions, the waste liquid tube 8 is always filled with the waste liquid, and the waste liquid is collected from the clean room to the waste liquid recovery tank 7 while preventing the waste liquid from drying.

When the waste liquid collecting tank 7 is full, the automatic opening / closing valve 9 is closed by the detection of the liquid amount sensor 13,
The waste liquid recovery tank 7 is replaced. At this time, since the volume of the liquid storage tank 3 is ensured to be equal to or larger than the amount of waste liquid generated within the time required for replacement of the waste liquid recovery tank 7, the resist coating apparatus 11 can be continuously operated, but the replacement work requires a predetermined time or more. If a trouble such as occurs, or the waste liquid accumulates up to the position of the limit sensor 6, the resist coating device stops.

According to the present embodiment, the flow control valve 1
0, the amount of waste liquid used for one wafer (resist, rinse, etc.) is passed from the waste liquid tube 8 to the waste liquid recovery tank 7 at the wafer processing interval. Since the waste liquid is replenished into the storage tank 3, the amount of waste liquid in the liquid storage tank 3 is stabilized at an amount slightly smaller than the upper limit, and the waste liquid always flows through the waste liquid tube 8, so that the waste liquid tube 8 It can be prevented from sticking and clogging due to drying or the like. Other effects are similar to those of the first embodiment.

Although FIG. 2 shows one resist waste liquid collecting device attached to one resist coating device 11 for one waste liquid collecting tank 7, a plurality of resist coating devices are provided. The same effect can be obtained even if the waste liquids of the plurality of resist waste liquid recovery apparatuses of the apparatus 11 are collectively collected by one waste liquid recovery tank 7.

FIG. 3 is a structural diagram showing a main part of a third embodiment of the resist waste liquid collecting apparatus according to the present invention. In this example, two waste liquid collecting devices 7A and 7B are installed outside the clean room with respect to one resist waste liquid collecting device attached to one resist coating device (not shown).

Initially, the switching valve 17 is switched to the waste liquid collecting device 7A side by the control unit 16, and the waste liquid flowing through the waste liquid tube 8 is collected in the waste liquid collecting tank 7A. Thereafter, when the waste liquid collecting layer 7A becomes full of the waste liquid and this is detected by the liquid amount sensor 13A and notified to the control unit 16, the control unit 16 switches the switching valve 17 to the waste liquid collecting layer 7B side.

Thus, the waste liquid flowing through the waste liquid tube 8 is discharged to the waste liquid collecting layer 7B and collected. During this time, if the waste liquid recovery tank 7A is replaced, the waste liquid recovery layer 7
When B is full of waste liquid, it switches to waste liquid recovery layer 7A. Further, even if a replacement trouble occurs when the waste liquid recovery tank 7A is replaced, there is a considerable amount of time before the waste liquid recovery tank 7B becomes full. Therefore, the trouble is processed to prepare an empty waste liquid recovery tank 7A. Since it is possible to keep sufficient time, it is possible to avoid stopping the resist coating apparatus due to a trouble in replacing the waste liquid collecting tank, and it is possible to improve the operation rate of the resist coating apparatus. Other operations of this example are the same as those of the first embodiment shown in FIG. 1, and the other effects are the same as those of the first embodiment.

[0035]

As described in detail above, according to the first and second aspects of the present invention, the resist waste liquid can be automatically collected in the waste liquid recovery tank outside the clean room without manual operation.

According to the third aspect of the present invention, there are a plurality of waste liquid recovery tanks, and when the tank is full, the waste liquid recovery tanks are switched and used.
It is not necessary to stop the resist coating device even in the event of a trouble in the waste liquid recovery tank, and the operation rate can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first embodiment of a resist waste liquid collecting apparatus according to the present invention.

FIG. 2 is a schematic view showing a second embodiment of the resist waste liquid collecting apparatus according to the present invention.

FIG. 3 is a schematic view showing a main part of a third embodiment of the resist waste liquid collecting apparatus of the present invention.

FIG. 4 is a schematic diagram showing a configuration example of a conventional resist waste liquid collecting apparatus.

FIG. 5 is an explanatory view showing an example of a conventional resist waste liquid collecting operation.

[Explanation of symbols]

 Reference Signs List 1 semiconductor wafer 2 resist coating cup 2A waste liquid hole 3 liquid reservoir 4 upper limit sensor 5 lower limit sensor 6 limit sensor 7, 7A, 7B waste liquid recovery tank 8 waste liquid tube 9 automatic open / close valve 10 manual flow control valve 11 resist coating device 13, 13A, 13B Liquid level sensor 14 Rotating rod 15 Resist dripping device 16 Control unit 17 Switching valve 31 Branch pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadatoshi Tsuchiya 25-1, Ekimae Honcho, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside (72) Inventor Shinichi Saito 25-1, Ekimae-Honcho, Kawasaki-ku, Kawasaki-shi, Kanagawa Toshiba Microelectronics Corporation

Claims (3)

[Claims] 1. A resist waste liquid collecting apparatus for collecting waste liquid from a resist coating apparatus for performing resist processing on a semiconductor wafer into a waste liquid collecting tank, comprising: a liquid storage tank for storing the waste liquid; A waste liquid tube for flowing waste liquid to the waste liquid recovery tank, an open / close valve provided on an opening side of the waste liquid tube to open and close the waste liquid tube, a sensor unit for detecting a waste liquid amount in the liquid storage tank, When it is detected that the amount of waste liquid in the liquid storage tank has reached the upper limit, the opening and closing valve is opened, and when it is detected that the amount of waste liquid has reached the lower limit, a control unit that performs control to close the opening and closing valve, A resist waste liquid recovery apparatus comprising: 2. A flow rate adjusting valve, which is inserted between a bottom side of the liquid storage tank and a side of the open / close valve of the waste liquid tube and adjusts a flow rate of waste liquid flowing through the waste liquid tube. Item 4. A resist waste liquid collecting apparatus according to Item 1. 3. A resist waste liquid collecting apparatus for collecting a waste liquid from a resist coating apparatus for performing a resist process on a semiconductor wafer into a waste liquid collecting tank, comprising: a liquid storage tank for storing the waste liquid; A waste liquid tube having a plurality of ends that branch waste liquid into a plurality of waste liquid collection tanks; an opening / closing valve provided before the branch of the waste liquid tube to open and close the waste liquid tube; and detecting a waste liquid amount in the liquid storage tank. A sensor unit, provided at a branch of the waste liquid tube, a switching valve for switching a flow path of the waste liquid tube so as to guide waste liquid to any one of the plurality of waste liquid collection tanks, and each of the plurality of waste liquid collection tanks A recovery tank sensor provided to detect the amount of waste liquid inside; and the opening and closing valve when the sensor unit detects that the amount of waste liquid in the liquid storage tank has reached an upper limit. Open, when it is detected that the waste liquid amount has reached the lower limit, performs control to close the open / close valve, and when the recovery tank sensor detects that the waste liquid in the one waste liquid recovery tank has reached the upper limit, the A control unit for controlling the switching valve to switch the waste liquid in the waste liquid tube to another waste liquid recovery tank, and a control unit for controlling the waste liquid.