JPH06151405A - Substrate drying method - Google Patents

Abstract

PURPOSE:To provide the title excellent substrate drying method leaving no water drips at all in the central part on the rear surface of a substrate especially useful for a liquid crystal substrate or a semiconductor substrate by a method wherein a gas is satisfactorily blown upon the central part on the rear surface of substrate for avoiding the re-adherence of water drips from a rotary shaft. CONSTITUTION:Within the title substrate drying method, the substrates 6 are rapidly turned while blowing a gas 7 upon the central part on the rear surface of the substrates 6 supported by a substrate supporter part 2 such as an arm, etc., fixed to a rotary shaft 3 and after entirely stopping the turning of the substrates 6 or holding at low speed, the gas discharge is to be stopped for resuming the rapid turning step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate drying method in a cleaning / etching process for liquid crystal displays, semiconductors and the like, and more particularly to a single wafer type spin drying.

[0002]

2. Description of the Related Art In conventional spin drying, as shown in FIG. 2 (A), a substrate support 2 mounted on a rotary shaft 21 is used.
2, the substrate 23 is placed on the substrate 2, and the substrate 23 is rotated to cause water droplets 2 attached to the surface of the substrate 23 by centrifugal force.
6 is scattered to dry the substrate.

However, at this time, since the centrifugal force does not work at the center of rotation of the substrate 23, water droplets 26 remain and cause stains or corrosion of the apparatus in the next process.

On the surface of the substrate, the water droplets 26 can be removed by spraying a gas 25 such as nitrogen from above the substrate 23 with a nozzle 24.

There is also a method of blowing the gas 25 onto the center of rotation from the nozzle 27 on the back surface of the substrate. As a drying method at this time, as shown in FIG. 2 (B), the rotating shaft 21 is rotated at a high speed, and at the same time, the gas 28 is blown out, the gas 28 is stopped after standing for t ₁ seconds, and then t ₂ seconds. It is rotating at high speed.

[0006]

Since the drying is performed in the sequence as shown in FIG. 2B, the substrate 28 is rotated at a high speed during the discharge of the gas 28, and thus the gas 28 is discharged. And the central part of the substrate is not dried sufficiently. Further, even if the water droplets are reattached from the substrate supporting portion 22, the water droplets remain on the central portion of the back surface of the substrate 23, and sufficient drying is not performed.

There is also a method in which a piping line 29 is provided in the rotary shaft 21 and gas is blown to the center of the back surface of the substrate 23, but it is difficult to process and a seal or the like has a complicated structure although not shown. Therefore, the device cost becomes high.

[0008]

In order to solve the above problems, the present invention rotates a substrate at a high speed while blowing gas onto the center of the back surface of the substrate supported by a supporting portion such as an arm attached to a rotating shaft. After that, after stopping the rotation of the substrate or holding it at a low speed, the discharge of the gas is stopped and the substrate is rotated at a high speed again.

[0009]

According to the above means, during high speed rotation, the water droplets on the peripheral portion of the substrate are splashed to the surroundings by the centrifugal force, and the water droplets on the rotating shaft and the supporting portion near the central portion are generated by the gas blown to the central portion of the back surface. After being blown away, it is blown to the surroundings by rotation. As a result, almost all but the water droplets near the center of the back surface of the substrate are removed. Next, by lowering the rotation speed to low speed, the gas blown to the central part of the back surface of the substrate can reach the water droplet part in the central part of the back surface of the substrate sufficiently because the disturbance by the substrate support part becomes small, and the water droplets remaining in the central part Move from the center of rotation. Finally, by stopping the blowing of the gas and rotating it at a high speed, the water drops remaining on the back surface are blown to the surroundings by the centrifugal force, and a good dry substrate is obtained.

However, if the blowing of the gas to the substrate is not stopped finally, the water droplets remaining in the center of the shaft may adhere to the back surface of the substrate again.

[0011]

EXAMPLE An example of the present invention will be described in detail below. FIG. 1A is a schematic view of an embodiment of the present invention.
The substrate rotating mechanism installed in the drying tank 1 is composed of a substrate supporting portion 2 and a rotating shaft 3 connected to the substrate supporting portion 2, and the rotating shaft 3 is connected to a servomotor 4 installed outside the drying tank 1. . Further, the nozzle 5 was installed near the center of the back surface of the substrate 6 at a position where the gas 7 could be blown. The nozzle 5 was connected to a gas pipe line 8 and the supply of the gas 7 was controlled by an electromagnetic valve 9.

At this time, the electromagnetic valve 9 and the servo motor 4 are controlled by the programmable controller 10 as shown in FIG.
The synchronous operation as shown in (B) was performed. FIG. 1B is a time chart of the drying method of this embodiment. From the drying start t ^'up to _one second of the substrate 6 while blowing gas 7 is rotated at high speed (1800 rpm), ^t' is from ₁ t ^'up to ₂ spraying said gas 7 at low speed (50 rpm). Finally the ^'from ₂ ^t' t until ₃ is rotated at a high speed of the substrate 6 by stopping the discharge of the gas 7.

[0013] Incidentally, the same effect without starting substrate rotation and the gas blowing start match is obtained, the same effect even intermittent ejection not continuous discharge gas blown from the start t ^'up to ₂ can get.

The results of some drying experiments are shown below (Table 1). Experiment 1 was based on the drying method of the present invention, and good drying results were obtained. In the case of Experiment 2, the water droplets remaining on the substrate supporting portion 2 were redeposited by the gas 7 at the last high speed rotation, and remained on the central portion of the back surface of the substrate 6. In the case of Experiment 3, the gas 7 did not reach the center of the back surface of the substrate 6 sufficiently, so that the gas 7 remained at the center of the back surface of the substrate 6. In the case of Experiment 4, since the water droplets on the substrate supporting portion 2 were not removed at the first high speed rotation, a large amount of water droplets on the substrate supporting portion 2 adhered to the back surface of the substrate 6 by spraying the gas 7 at the low speed rotation. It remains because I did it.

[0015]

[Table 1]

[0016]

As described above, according to the drying method of the present invention, the gas is made to sufficiently reach the central portion of the back surface of the substrate, and the re-adhesion of water droplets from the rotary shaft is prevented, so that the water droplets are deposited on the central portion of the back surface of the substrate. Good substrate drying without leaving
This is possible with a simple device configuration.

[Brief description of drawings]

FIG. 1A is a configuration diagram of an apparatus embodying a drying method of the present invention, and FIG. 1B is a time chart diagram of the apparatus during operation.

FIG. 2A is a configuration diagram of a conventional drying device, and FIG. 2B is a time chart diagram during operation of the conventional drying device.

[Explanation of symbols]

 1 Drying Tank 2 Substrate Support 3 Rotating Shaft 4 Servo Motor 5 Nozzle 6 Substrate 7 Gas 8 Gas Piping Line 9 Electromagnetic Valve 10 Programmable Controller

Claims (1)

[Claims] 1. After rotating the substrate at a high speed while blowing gas onto the center of the back surface of the substrate supported by a supporting portion such as an arm attached to a rotating shaft, after stopping the rotation of the substrate or holding it at a low speed. A method of drying a substrate, characterized in that the discharge of the gas is stopped and the high speed rotation is performed again.