JPH02293629A - Liquid level gage for semiconductor wet process device - Google Patents

Abstract

PURPOSE:To make the level measurement of liquid without contaminating wafers by providing a detecting part for the strain quantity by a liquid weight and a liquid temp. measuring part in the outside bottom of the semiconductor wet process device and correcting the measured strain quantity with the measured liquid temp. CONSTITUTION:The weight of the processing liquid 5 in a processing tank 4 changes and the strain in the bottom of the tank 4 changes when the level of the liquid 5 changes. This change is converted to a current change by a strain gage 6. A temp. measuring body 7 of the temp. measuring part 2, which is stuck to the outside bottom of the tank 4, converts the temp. change to a current change. The current change of the strain gage 6 is detected by a strain gage current change detecting circuit 9 and is converted to the voltage corresponding to the strain quantity. The current change of the temp. measuring body 7 is detected by a measuring body current change detecting circuit 8 and is converted to the voltage corresponding to the temp. strain quantity. The voltage signal by the detecting circuit 8 is subtracted from the voltage signal by the detecting circuit 9 to form the voltage signal equiv. to the strain quantity corresponding to the volume of the treating liquid in a temp. correcting circuit 10. This voltage signal is converted to a liquid level height in a liquid level computing circuit 11. The result thereof is displayed in a display section 12 and is outputted from an external output circuit 13 to an external device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid level gauge used in a processing tank of a semiconductor wet processing apparatus.

[Conventional technology]

Conventionally, this type of liquid level type includes a float type, an air sensor type, a capacitance type, an ultrasonic type, etc.

FIG. 4 is a longitudinal cross-sectional view of a float type liquid level gauge, which is an example of the conventional technology. When the processing liquid reaches the level of the float 18, the float 18 containing the magnet 19 floats up. When the float l♂ floats up, the lead 2l contacts the contact point 20 due to magnetic force, and the contact is detected by the signal line 22, causing the float! You can now confirm that the liquid level is at level 8.

[Problem to be solved by the invention]

The above-mentioned conventional liquid level gauges have the disadvantage that because the detection part such as a float is placed directly into the processing liquid, there is a high possibility that heavy metals, particles, etc. will be eluted from the detection part into the processing liquid and contaminate the wafer. There is.

[Means to solve the problem]

The present invention provides a liquid level gauge for semiconductor processing equipment used in a processing tank of a semiconductor wet processing equipment, and includes a strain amount detection section that is provided at the outer bottom of the processing tank and detects the amount of distortion in the processing tank due to the weight of liquid in the processing tank. , a temperature measuring section which is also provided at the outer bottom of the processing tank and detects the temperature change of the processing tank due to the liquid temperature, and a temperature signal from this temperature measuring section is converted into a strain amount signal and the distortion amount signal from the strain amount detection section is detected. The present invention is a liquid level meter for a semiconductor wet processing device, which includes a calculation unit that corrects a quantity signal and calculates and displays a liquid level height from the corrected distortion quantity signal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram showing a first embodiment of the present invention. A signal corresponding to the amount of strain is input to the calculation unit 3 from the strain amount detection unit 1 provided at the outer bottom of the processing tank 4, and a signal corresponding to the amount of strain is input to the calculation unit 3, and the temperature at the outer bottom of the processing tank is detected from the temperature measurement unit 2 similarly provided. The corresponding signal enters the calculation section 3.

The calculation unit 3 calculates the liquid level height based on the strain signal and the temperature signal, and displays it or takes it out as an output signal to the outside.

Figure 2 is a system configuration diagram of the present invention. Distortion amount detection section 1
consists of a strain gauge 6 attached to the outer bottom of the processing tank 4. When the liquid level of the processing liquid 5 in the processing tank 4 changes, the weight of the processing liquid 5 changes, so the load applied to the bottom of the processing tank 4 changes, and the strain at the bottom of the processing tank 4 changes. The strain gauge 6 converts this change in strain amount into a current change.

Further, the temperature measuring section 2 consists of a temperature measuring element 7 attached to the outer bottom of the processing tank 4, and the temperature measuring element 7 converts temperature changes into current changes.

Current changes in the strain gauge 6 are detected by a strain gauge current change detection circuit 9.
is detected and converted into a voltage corresponding to the amount of distortion. A current change in the temperature measuring element 7 is detected by a temperature measuring element current change detection circuit 8 and converted into a voltage corresponding to the amount of temperature distortion.

In addition, the temperature correction circuit 10 subtracts the voltage signal from the temperature sensing body current change detection circuit 8 from the voltage signal from the strain gauge current change detection circuit 9 to create a voltage signal corresponding to the amount of strain corresponding to the amount of processing liquid.

This voltage signal is converted into a liquid level height by the liquid level calculation circuit 11, and the result is displayed on the display section l2, and the external output circuit l
3 to an external device.

FIG. 3 is a schematic diagram showing a second embodiment of the present invention. In the first embodiment, the strain amount detection section 1 and the temperature measurement section 2 were provided directly on the exterior of the processing tank 4, but in this embodiment, as shown in the figure, the strain detection section 1 and the temperature measurement section 2 were provided directly on the tank support 14 of the outer tank 15. A strain detection section 1 and a temperature measurement section 2 are installed in the processing tank 4. Since there is no strain detection section 1 and temperature measurement section 2 directly below the processing tank 4, an ultrasonic oscillator vibrator 16, etc. is attached here. It has the advantage of being able to

〔Effect of the invention〕

As explained above, since the present invention has a part that detects the liquid level outside the processing tank, impurities are less likely to be eluted from the detection part into the processing liquid, compared to a case where the detection part is inside the processing liquid. Since there is no detection section inside the processing tank, the wafers are not contaminated, and since there is no detection section inside the processing tank, the tank capacity can be reduced, which has the effect of reducing the amount of processing liquid used.

3 is a schematic diagram of a second embodiment of the present invention, and FIG. 4 is a vertical sectional view of a conventional float type liquid level gauge.

DESCRIPTION OF SYMBOLS 1... Strain amount detection part, 2... Temperature measurement part, 3... Calculation part, 4... Processing tank, 5... Processing liquid, 6... Strain gauge, 7... Measurement Warm body, 8... Temperature sensing body current change detection circuit, 9... Strain gauge current change detection circuit, 10... Temperature correction circuit, 11... Liquid level calculation circuit, l2... Display section, l3... External output circuit, 14... Tank support stand, 1
5... Outer tank, l6... Vibrator for ultrasonic oscillator, 17
...Column, l...Float, 19...Magnet, 20.
...Contact, 2l...Lead, 22...Signal line.

Claims (1)

[Claims] In a liquid level gauge for semiconductor processing equipment used in a processing tank of a semiconductor wet processing equipment, there is a strain amount detection section that is provided at the outer bottom of the processing tank and detects the amount of distortion in the processing tank due to the weight of the liquid in the processing tank, and a temperature measuring section installed on the outer bottom of the unit to detect temperature changes in the processing tank due to liquid temperature, and converting the temperature signal from the temperature measuring section into a strain amount signal to correct the strain amount signal from the strain amount detecting section. 1. A liquid level gauge for a semiconductor wet processing device, comprising: a calculation unit that calculates and displays a liquid level height from a distortion amount signal after correction.