JP3168606B2 - Chemical coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical liquid applying apparatus in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art FIG. 2 is a cross-sectional view of an exhaust pipe system of a conventional chemical liquid applicator. In the coating processing unit 1, a chemical solution 5 dropped from a chemical solution nozzle 4 is spin-coated on a semiconductor substrate 3 fixed by suction to a vacuum suction plate 2. A chemical liquid waste liquid port 6 and an exhaust port 7 for exhausting a chemical liquid atmosphere in the processing section are provided below the coating processing section 1. The chemical liquid droplet catcher 8 below the exhaust port 7 prevents chemical liquid droplets from entering the exhaust pipe 9 and clogging the pipe, and generally uses a metal net or the like.

The exhaust in the coating section 1 is indispensable not only for removing the chemical atmosphere but also for suppressing the rebound of the chemical in the coating section 1 during the spin coating, and the exhaust flow rate is smaller than an appropriate amount. And the semiconductor substrate 2 by rebound
It is known that the contamination of the water occurs. On the other hand, it is known that, when the exhaust flow rate is larger than the appropriate amount, the uniformity of the coating film thickness deteriorates. Therefore, in order to perform coating with a uniform film thickness and without contamination due to rebound of a chemical solution, it is necessary to keep an appropriate exhaust flow rate constant.

[0004] A constant flow control valve 10 attached to an exhaust pipe 9 in the figure is feedback-controlled by an exhaust wind speed sensor 11 also attached to the exhaust pipe 9. The constant flow control valve 10 moves in a direction in which the valve closes when the exhaust wind speed increases, and in a direction in which the valve opens when the exhaust wind speed decreases, so that the exhaust wind speed is controlled to be always constant, so that the exhaust flow rate is also constant. The above is a method of stabilizing the exhaust flow rate that is generally used. The reason why such a method must be used is that the exhaust flow rate of the coating processing unit varies for the following two reasons.

The first reason is that droplets of the coating solution enter the exhaust pipe and clog the pipe. Normally, the use of the above-mentioned chemical liquid droplet catcher is used to prevent the penetration of the chemical liquid droplets. The exhaust flow rate of the section decreases. Therefore, it is necessary to periodically replace the chemical liquid droplet catcher.

[0006] The second reason is a fluctuation in factory exhaust pressure.
Generally, the exhaust pipe of the coating processing section is connected to factory exhaust. Normally, since various equipments share this factory exhaust line, the exhaust pressure fluctuates depending on the amount of exhaust gas used by other equipment, and therefore the exhaust flow rate also fluctuates.

[0007]

In the above-described conventional exhaust flow rate control, there is a problem that the control exhaust flow rate fluctuates due to contamination of the exhaust wind speed sensor by the splash of a chemical solution. That is,
Most of the chemical droplets are captured by the chemical droplet catcher,
A part of the exhaust gas flows into the exhaust pipe, and the exhaust air speed sensor is generally a thermal sensor. If a foreign substance adheres to the sensor surface, the sensitivity of the sensor decreases, and the sensor detects the exhaust air speed lower than the true exhaust air speed. Therefore, in this state, since the constant flow control valve is controlled to open, the controlled exhaust gas flow becomes larger than the true value. That is, a phenomenon occurs in which the control exhaust gas flow rate gradually increases from an appropriate value while the coating process is continued.

[0008] Due to this phenomenon, the uniformity of the thickness of the chemical solution applied on the surface of the semiconductor substrate deteriorates. For example, taking a photoresist as an example, the current technology is said to have a thickness of about 1 μm and a thickness variation within 30 Å. Although it depends on the degree, when the exhaust flow rate in the coating processing section is larger than an appropriate amount, there is a good possibility that the film thickness variation becomes twice or more of the normal thickness, that is, 60 Å or more.

In the prior art, the increase in the exhaust gas flow rate cannot be corrected, and the exhaust gas flow rate sensor must be regularly cleaned. In addition, the cleaning must be performed quite frequently in view of the margin of the risk to the deterioration of the uniformity of the film thickness of the chemical solution.

[0010]

A chemical solution applying apparatus according to the present invention is a chemical solution applying apparatus having a function of controlling an exhaust air velocity of a chemical solution applying section, comprising: an exhaust pipe connected to a lower portion of the chemical solution applying section; A chemical liquid droplet catcher provided in the exhaust pipe to prevent chemical liquid droplets from the chemical liquid application processing section from entering the exhaust pipe and clogging the exhaust pipe; and an external air suction branched and connected to the exhaust pipe. It is characterized by comprising a pipe, and an exhaust wind speed sensor provided in the outside air suction pipe and measuring a wind speed in the outside air suction pipe.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a piping system according to one embodiment of the present invention. The difference from the conventional technique is that the exhaust air speed sensor 11 is installed in an outside air suction pipe 12 connected to an exhaust pipe immediately below the coating processing unit 1.

The measured exhaust wind speed is the wind speed in the outside air suction pipe 12, and the constant flow control valve 10 is also controlled by the exhaust wind speed. The necessary condition in this case is that when the exhaust through the exhaust pipe 9 sets the constant flow control valve 10 to the fully open state,
That it is capable of sufficiently exceeding the required exhaust flow rate. In other words, it is necessary to have an exhaust capability sufficient to compensate for the exhaust flow rate of the coating processing unit, which is lower than originally expected due to the intake of outside air.

Since both the outside air suction and the exhaust of the coating processing section 1 are performed through the exhaust pipe 9, the constant flow control valve 10
Is set so that the exhaust flow rate of the coating processing section 1 becomes an appropriate value, the exhaust flow rate of the coating processing section can be made constant, similarly to the conventional technique. The outside air suction from the outside air suction pipe 12 can be used for the purpose of exhausting the application liquid storage section unless the usage that changes the suction amount or the usage that pollutes the exhaust air velocity sensor 11 is used. . Therefore, under such usage, the exhaust capacity is not reduced as a whole.

In this embodiment, the constant flow control valve 11 is always operated by measuring the wind speed of the air sucked from the outside air suction pipe.
, The contamination of the exhaust air velocity sensor due to the application chemical liquid droplets, which has been a problem in the prior art, cannot occur.

[0015]

As described above, according to the present invention, the control of the constant flow control valve is performed by the exhaust air velocity sensor in the outside air intake pipe, so that the contamination of the exhaust air velocity sensor due to the application chemical liquid droplets can be eliminated. Therefore, the phenomenon that the exhaust flow rate of the coating processing section increases due to the contamination of the exhaust air velocity sensor is solved, and the variation of the chemical liquid coating film thickness on the semiconductor substrate due to this phenomenon is eliminated, thereby improving the yield of semiconductor products in semiconductor manufacturing. Can be done.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional chemical liquid application device.

[Description of Signs] 1 Coating section 2 Vacuum suction plate 3 Semiconductor substrate 4 Chemical liquid nozzle 5 Chemical liquid 6 Chemical liquid waste port 7 Exhaust port 8 Chemical liquid splash catcher 9 Exhaust pipe 10 Constant flow control valve 11 Exhaust air velocity sensor 12 External air intake pipe

Claims (1)

(57) [Claims] 1. A chemical liquid application device having a function of controlling an exhaust air velocity of a chemical liquid application processing part, wherein a lower part of the chemical liquid application processing part is provided.
An exhaust pipe connected to the exhaust pipe,
Splashes of the chemical from the chemical application section enter the exhaust pipe
To prevent the exhaust pipe from clogging
A foot unit and an outside air intake pipe branched and connected to the exhaust pipe
And provided in the outside air suction pipe,
A chemical liquid applicator, comprising: an exhaust air velocity sensor for measuring a wind velocity .