KR20020028699A - Apparatus for cleaning semiconductor products and method of controlling concentration of a cleaning solution contained in a cleaning tube of the apparatus - Google Patents

Abstract

PURPOSE: An apparatus for cleaning a semiconductor device is provided to improve productivity and yield of the semiconductor device, by uniformly maintaining the density of cleaning solution in a cleaning bath at all times. CONSTITUTION: The semiconductor device to clean and the cleaning solution are contained in the cleaning bath(10). A compound supply source supplies a compound to the cleaning bath. An electrical conductivity measuring unit(60) measures the electrical conductivity of the cleaning solution in the cleaning bath, and supplies an electrical conductivity data signal corresponding to the measured electrical conductivity. A controller(70) controls the quantity of the compound supplied from the compound supply source to the cleaning bath in response to the electrical conductivity data signal.

Description

FIELD OF THE CLEANING SOLUTION CONTAINED IN A CLEANING TUBE OF THE APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to semiconductor product cleaning apparatuses, and more particularly, to automated cleaning apparatuses and control methods thereof.

In general, in the process of manufacturing a semiconductor product such as a liquid crystal display (LCD) panel or a semiconductor wafer, each product is cleaned to remove impurities after a unit process.

Particularly, in manufacturing an active matrix thin film transistor LCD panel which is widely used at present, high molecular organic materials or inorganic materials are used for the alignment of liquid crystals, and since these surfaces may contaminate the surface of the liquid crystal display panel, It is necessary to clean the panel after completion of each unit process related to the material (eg encapsulation process after liquid crystal injection).

Currently, in the manufacturing process of the LCD panel, an aqueous cleaning solution mixed with deionized water is widely used. Aqueous cleaning liquids have excellent detergency but are required to maintain a constant ratio of water (ie, pure water) at all times.

During the cleaning process using an aqueous cleaning liquid, the LCD panel is typically cleaned in a cleaning bath. In the subsequent cleaning process, the cleaning liquid moisture ratio is different from the desired ratio due to the evaporation of the cleaning liquid moisture. If the water is not maintained at an appropriate ratio due to the characteristics of the aqueous washing solution, its cleaning power is significantly lowered. In order to prevent this, engineers have conventionally measured the concentration of the cleaning liquid in the cleaning tank and supplied pure water and / or the cleaning liquid to the cleaning tank, but it is difficult to systematically manage it.

On the other hand, when the concentration of the washing liquid in the washing tank is different from the desired concentration in the washing process, the washing liquid in the washing tank may be completely discarded, and the washing liquid of an appropriate concentration may be newly supplied to the washing tank, in which case the production cost increases.

It is therefore an object of the present invention to provide an automated semiconductor product cleaning apparatus and its control method capable of maintaining a constant concentration of the cleaning liquid in the cleaning tank.

1 is a view showing a first embodiment of the cleaning apparatus according to the present invention,

2 is a view showing a second embodiment of the cleaning apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

10, 110: washing tank 12, 112: main washing tank

14, 114: auxiliary cleaning tank 16, 116a, 116b: inlet pipe

18a, 18b, 118a, 118b: discharge pipe 20, 120: pure water tank

30, 130: mixing tank 40, 140, 180: electric valve

50, 150: motor 60, 160: conductivity meter

70, 170: controller

In order to achieve the above object, the present invention has been invented using the fact that the electrical conductivity of the solution depends on the kind of substance contained in the solution and the concentration of the solution.

According to one aspect of the present invention, a cleaning apparatus for cleaning a semiconductor product, such as a liquid crystal display (LCD) panel, a semiconductor wafer, or the like, measures an electrical conductivity of a cleaning liquid in a cleaning tank and provides a conductivity data signal corresponding to the measured electrical conductivity. And a controller for controlling the amount of the mixture (eg, pure water) supplied to the cleaning bath in response to the conductivity data signal.

The semiconductor product cleaning apparatus according to the first preferred embodiment includes a pure water tank for supplying pure water, a washing tank for containing the semiconductor product to be cleaned and a cleaning liquid, and a valve electrically controllable from the pure water tank (hereinafter referred to as 'electric valve'). A mixing tank for mixing the pure water supplied through the cleaning liquid and the cleaning liquid discharged from the cleaning tank, and an electrical power measuring the electrical conductivity of the cleaning liquid supplied from the mixing tank to the cleaning tank and providing a conductivity data signal corresponding to the measured conductivity. And a conductivity meter and a controller for controlling the amount of pure water supplied from the pure water tank to the mixing tank by controlling the opening and closing of the electric valve in response to the conductivity data signal.

The semiconductor product cleaning apparatus according to the second preferred embodiment includes a pure water tank for supplying pure water, a cleaning tank connected to the pure water tank through a first electric valve and containing a semiconductor product to be cleaned and a cleaning liquid, and a pure water tank. 2 A mixing tank for mixing the pure water supplied through the electric valve and the cleaning liquid discharged from the cleaning tank, and measuring the electrical conductivity of the cleaning liquid discharged from the cleaning tank to the mixing tank and providing a conductivity data signal corresponding to the measured electrical conductivity. And a controller for controlling the amount of pure water supplied from the pure water tank to the mixing tank and the washing tank, respectively, by controlling the opening and closing of the first and second electric valves in response to the conductivity data signal.

According to another feature of the present invention, there is provided a method capable of automatically controlling the concentration of the cleaning liquid in the cleaning tank. According to this method, the cleaning liquid is supplied to the cleaning tank of the cleaning apparatus for cleaning semiconductor products such as LCD panels, semiconductor wafers, etc., the electrical conductivity of the water-based cleaning liquid in the cleaning tank is measured, and supplied to the cleaning tank according to the measured electrical conductivity. The amount of mixture to be controlled is controlled.

According to the present invention as described above, since the concentration of the cleaning liquid in the cleaning tank can be kept constant at all times, the productivity and yield of the product can be improved.

Hereinafter, the present invention will be described in detail.

"Electric conductivity of a solution" refers to the degree to which a solution can carry current.The meter applies a constant voltage to two electrodes in a solution, and current flows through the solution. It uses the fact that it depends on electrical conductivity. Electrical conductivity is the inverse of the electrical resistance component, the unit of which is mho or S (Siemens).

In general, the resistance component R of the solution measured by the conductivity meter can be represented by the following equation (1).

R = ρ · ι / A

Where ρ is the resistivity of the solution and its unit is Ω, ι is the distance between the two electrodes, its unit is cm, A is its cross-sectional area and its unit is cm 2.

Therefore, the electrical conductivity L of the solution may be represented by the following equation (2).

L = 1 / R = (AK) / A

Here, K is the specific conductivity of the solution, which is equal to 1 / ρ, and the unit is mho / cm.

The conductivity of a solution varies with the type of material in the solution, the concentration of the solution, and the temperature of the solution. Therefore, it is possible to calculate the concentration of the solution if the kind of material constituting the solution and the electrical conductivity of the solution are known under a constant temperature.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Herein, the present invention will be described in detail through the cleaning process of the LCD panel, which is one of the semiconductor products, for convenience. In addition, although the case where an aqueous washing liquid is used as the washing liquid and deionized water is used as the mixture is described here, even when other washing liquids (eg, HF solution, H ₂ O ₂ solution) and mixtures thereof are used, The principle can be applied.

<First Embodiment>

1 is a view showing a first embodiment of the cleaning apparatus according to the present invention. Referring to FIG. 1, the cleaning apparatus includes a cleaning tank 10 containing an LCD panel to be cleaned and an aqueous cleaning solution for cleaning the panel, and a pure water tank (or mixture tank) storing pure water, which is a mixture mixed with the cleaning liquid. (20) and a mixing tank (30) for mixing the washing liquid discharged from the washing tank (10) and the pure water supplied from the pure water tank (20) to supply to the washing tank (10) again.

An electric valve 40 is installed in the pipe 22 connecting the pure water tank 20 and the mixing tank 30 to each other. The opening and closing of the valve 40 opens and closes the mixing tank 30 from the pure water tank 20. Pure water can be supplied or not supplied. Only when the washing liquid and the pure water are not maintained at an appropriate ratio, the valve 40 is opened to supply pure water from the pure water tank 20 to the mixing tank 30.

The cleaning tank 10 is disposed at the center portion and has a main cleaning tank 12 having an inlet pipe 16, and an auxiliary cleaning tank having two discharge pipes 18a and 18b disposed above the main cleaning tank 12. It consists of 14. The inlet pipe 16 of the cleaning tank 10 or 12 is connected to the mixing tank 30 through the pump 50. The pump 50 allows the washing liquid to be supplied to the washing tank 10 or 12 at a constant pressure under the control of the controller 70. The washing liquid overflowed from the main washing tank 10 is stored in the auxiliary washing tank 14. The cleaning liquid contained in the auxiliary cleaning tank 14 is discharged to the mixing tank 30 through the discharge pipes 18a and 18b.

An inductance tube 16 of the cleaning tank 10 or 12 is provided with a conductivity meter 60. The conductivity meter 60 measures the conductivity of the cleaning liquid supplied from the mixing tank 30 to the cleaning tank 10 or 12 through the pump 50 and controls the conductivity data signal COND corresponding to the measured conductivity. Provided by 70. The conductivity meter 60 may be an analog device or a digital device. When an analog meter is used, the analog conductivity data may be integrated into an analog-to-digital converter (ADC) integrated in the controller 70 or a separate ADC. Is converted into digital data. The core portion (ie, digital circuit portion) of the controller 70 detects the concentration of the cleaning liquid using digital data provided from the ADC.

Temperature measurement must be taken into account to measure the concentration of cleaning solutions using electrical conductivity in LCD panel (or semiconductor product) manufacturing lines. In general, the electrical conductivity is known to show a difference of about 2% / ℃. For this reason, the change data of the electrical conductivity of the cleaning liquid according to the kind of material constituting the cleaning liquid and the temperature change are stored in advance in an internal memory (not shown) of the microcomputer used as the controller 70. Of course, alternatively, such data may be provided from the outside to the controller 70 at the beginning of the operation of the cleaning apparatus.

The controller 70 receives ambient temperature data from the outside to recognize the ambient temperature, corrects the conductivity data COND of the conductivity meter 60 based on the conductivity data suitable for the temperature, and based on the corrected data. To determine the electrical conductivity of the solution. Thereafter, the controller 70 calculates the concentration of the cleaning liquid using the electrical conductivity of the cleaning liquid, and generates a valve control signal V_CON corresponding to the concentration of the cleaning liquid.

The electric valve 40 is digitally controlled in a fully closed or fully open manner according to the logic value '0' or '1' of the control signal V_CON, or its opening is proportional to the voltage level of the control signal V_CON. It may be controlled in an analog manner that is adjusted.

The controller 70 controls the amount of pure water supplied from the pure water tank 20 to the mixing tank 30 by controlling the opening and closing of the electric valve 40 in response to the conductivity data signal COND. In this case, in order to prevent excessive amounts of pure water from being supplied to the mixing tank 30, the opening degree of the valve 40, the opening time, and the like may be limited.

The automated cleaning solution concentration control as described above can maintain the concentration of the cleaning solution in the cleaning tank at all times, thereby bringing an effect of improving the productivity and yield of the product.

Second Embodiment

2 is a view showing a second embodiment of the cleaning apparatus according to the present invention. Referring to FIG. 2, the cleaning apparatus of this embodiment includes a cleaning tank 110, a pure water tank (or a mixture tank) 120, a mixing tank 130, a pump 150, an electrical conductivity measuring instrument 160, and a controller. 170 is provided.

An electric valve 140 is installed in the pipe 122 connecting the pure water tank 120 and the mixing tank 130 to each other, and the mixing tank 130 is separated from the pure water tank 120 by opening and closing the valve 140. Pure water can be supplied or not supplied.

The cleaning tank 110 is disposed at the center portion and has a main cleaning tank 112 having two inflow pipes 116a and 116b, and a top of the main cleaning tank 112 and two discharge pipes 118a and 118b. It consists of the auxiliary washing tank 114 which has.

One inlet pipe 116a of the cleaning tank 110 or 112 is connected to the mixing tank 130 through the pump 150, and the other inlet pipe 116b is connected to the pure water tank 120 through the electric valve 180. Connected with The pump 150 allows the cleaning liquid to be supplied to the cleaning tank 110 or 112 at a constant pressure under the control of the controller 170.

The washing liquid overflowed from the main washing tank 110 is stored in the auxiliary washing tank 114. The cleaning liquid contained in the auxiliary cleaning tank 114 is discharged to the mixing tank 130 through the discharge pipes 118a and 118b.

An electrical conductivity meter 160 is installed in the discharge pipe 118a of the cleaning tank 110 or 114. The conductivity meter 160 measures the conductivity of the cleaning liquid discharged from the cleaning tank 110 and provides a conductivity data signal COND corresponding to the measured conductivity to the controller 170. The conductivity meter 160 may be an analog device or a digital device. When an analog meter is used, the analog conductivity data is converted into digital data by an ADC integrated in the controller 170 or a separate ADC. . The core portion (ie, digital circuit portion) of the controller 170 detects the concentration of the cleaning liquid using the digital data provided from the ADC.

The change data of the electrical conductivity of the cleaning liquid according to the kind of material constituting the cleaning liquid and the temperature change are stored in advance in the internal memory (not shown) of the microcomputer used as the controller 170. Of course, such data may be provided to the controller 170 from the outside at the initial stage of operation of the cleaning apparatus, as in the previous embodiment.

The controller 170 receives ambient temperature data from the outside to recognize the ambient temperature, corrects the conductivity data COND of the conductivity meter 160 based on the conductivity data suitable for the temperature, and based on the corrected data. To determine the electrical conductivity of the solution. Thereafter, the controller 170 calculates the concentration of the cleaning liquid using the electrical conductivity of the cleaning liquid, and generates valve control signals V_CON1 and / or V_CON2 corresponding to the concentration.

The electric valves 140 and / or 180 are digitally controlled to be fully closed or fully open according to the logic values '0' or '1' of the control signals V_CON1 and / or V_CON2, or the control signals V_CON1 and / or Alternatively, the opening may be controlled in an analog manner in which the opening is adjusted in proportion to the voltage level of V_CON2).

The controller 170 controls the opening and closing of the electric valve 140 and / or 180 in response to the conductivity data signal COND provided from the conductivity meter 160 and / or the cleaning tank 130. 110) to control the amount of pure water supplied. In this case, in order to prevent the excessive amount of pure water from being supplied to the mixing tank 130 and / or the cleaning tank 110, the opening degree of the valve 140 and / or 180 may be limited.

According to the present invention as described above, since the concentration of the cleaning liquid in the cleaning tank can be kept constant at all times, the productivity and yield of the product can be improved.

Claims (10)

A cleaning tank for containing a semiconductor product to be cleaned and a cleaning liquid; A mixture source for supplying the mixture to the cleaning bath; An conductivity meter for measuring the conductivity of the cleaning liquid in the cleaning bath and providing a conductivity data signal corresponding to the measured conductivity; And a controller for controlling the amount of the mixture supplied from the mixture source to the cleaning bath in response to the conductivity data signal. The method of claim 1, The washing liquid is an aqueous washing liquid, And the mixture is pure water. The method of claim 1, And the semiconductor product is a liquid crystal display panel or a semiconductor wafer. A pure water tank for supplying pure water; A cleaning tank for containing a semiconductor product to be cleaned and an aqueous cleaning solution; An electric valve; A mixing tank for mixing the pure water supplied from the pure water tank through the electric valve and the aqueous washing liquid discharged from the washing tank; An electrical conductivity meter for measuring the electrical conductivity of the water cleaning liquid supplied from the mixing tank to the cleaning tank and providing a conductivity data signal corresponding to the measured conductivity; And a controller for controlling the amount of pure water supplied from the pure water tank to the mixing tank by controlling the opening and closing of the electric valve in response to the conductivity data signal. The method of claim 4, wherein The semiconductor product semiconductor product, characterized in that the semiconductor product is a liquid crystal display panel. A pure water tank for supplying pure water; A cleaning tank connected to the pure water tank through a first electric valve and containing a semiconductor product to be cleaned and an aqueous cleaning liquid; A mixing tank for mixing the pure water supplied from the pure water tank through the second electric valve and the aqueous washing liquid discharged from the washing tank; An electrical conductivity meter for measuring the electrical conductivity of the water cleaning liquid discharged from the cleaning tank to the mixing tank and providing a conductivity data signal corresponding to the measured electrical conductivity; And controlling a quantity of the pure water supplied from the pure water tank to the mixing tank and the cleaning tank, respectively by controlling opening and closing of the first and second electric valves in response to the conductivity data signal. Semiconductor product cleaning apparatus. The method of claim 6, And said semiconductor product is a liquid crystal display panel. Supplying a cleaning liquid to a cleaning tank of a semiconductor product cleaning apparatus; Measuring the electrical conductivity of the cleaning liquid in the cleaning tank; And controlling the amount of the mixture supplied to the cleaning tank in accordance with the measured electrical conductivity. The method of claim 8, The washing liquid is an aqueous washing liquid, And the mixture is pure water. The method of claim 8, And the semiconductor product is a liquid crystal display panel or a semiconductor wafer.