KR100980025B1 - Method of controlling substrate's damage - Google Patents

Abstract

According to an aspect of the present invention, there is provided a method for controlling substrate damage in a dry etching apparatus including a dry etching plasma chamber and a power supply unit providing an electrode power source to the plasma chamber and having an impedance matching unit. Measuring at least one electrical parameter, and determining the occurrence of damage to the substrate when a value of the measured electrical parameter is changed within a predetermined range or more within a predetermined time. As a result, damage to the substrate generated in the dry etching apparatus can be controlled.

Description

METHOOD OF CONTROLLING SUBSTRATE'S DAMAGE}

1 is a plan view of a conventional dry etching device,

2 is a graph showing the relationship between change in current and occurrence of substrate damage;

3 is a graph showing a relationship between a change in voltage and occurrence of substrate damage;

4 is a graph showing a relationship between a change in current phase and occurrence of substrate damage;

5 is a graph showing a relationship between a change in impedance and occurrence of substrate damage;

6 is a plan view of a dry etching apparatus according to the present invention.

* Description of the symbols for the main parts of the drawings *

610: plasma chamber 620: power supply unit 630: sensor 640: determination unit

650 control unit

The present invention relates to a method for determining whether damage occurs to a substrate in a dry etching process and controlling the occurrence of damage.

The liquid crystal display device has a structure in which liquid crystal is injected between the color filter substrate and the thin film transistor substrate. The process of forming a thin film transistor array in manufacturing a double thin film transistor substrate is similar to a semiconductor manufacturing process. That is, it consists of processes such as thin film deposition, photography, and etching, and includes inspection to check the results and abnormalities before and after each process and cleaning to maintain cleanliness.

Among these, etching is a method of implementing the actual thin film pattern by selectively removing the thin film according to the pattern formed by the photoresist on the substrate by using physical and chemical reactions. The part is removed. The etching process includes dry etching using gas plasma and wet etching using chemical solution.

Wet etching is a method of removing a thin film in accordance with a photoresist pattern by using a chemical solution, and is mainly applied to pattern formation of a metal film or indium tin oxide (ITO). This method is advantageous for good selectivity, large surface area etching uniformity, productivity, and low cost, and at the same time achieves a cleaning effect.

In dry etching, the reaction gas is introduced into the chamber and the plasma is discharged under a constant pressure. When the plasma is discharged, the gas is separated into ions, radicals and electrons. At this time, collisions and mutual reactions occur by the applied electric field, ions react with the thin film on the substrate by the electric field, and radicals are etched by simultaneous action by physical collision and chemical reaction.

Dry etching by plasma may be classified into plasma etching and reactive ion etching according to the reaction method. Plasma etching method shows isotropic etching because radicals are mainly used for etching by the chemical reaction among the generated reactants, and has less physical impact, which is advantageous for selective etching. Reactive ion etching is mainly performed by etching ions colliding with the thin film due to the acceleration of the electric field, and is characterized by anisotropic etching according to the direction of the electric field.

1 is a plan view of a conventional dry etching apparatus.

The dry etching apparatus has a plasma chamber 110 and a power supply unit 120. The chamber 110 has a receptor 111, a lower electrode 112, and an upper electrode 113.

The receptor 111 supports a panel coated with a photosensitive liquid for etching and forms a lower space of the chamber space, and the lower electrode 112 is formed in contact with the bottom surface of the receptor 111. The upper electrode 113 is positioned in the upper space inside the chamber 110 and is grounded as a reference electrode for the lower electrode 112.

The power supply unit 120 is an AC power source having a predetermined frequency and a predetermined amplitude, and is connected to the lower electrode 112. The impedance matching unit 122 is connected between the lower plate electrode and the power source 121 to prevent the AC power applied from the main power source 121 from being reflected by the lower plate electrode 112 and flowing backward.

A vacuum pump is used to discharge the gas present in the chamber 110 through a gas discharge port (not shown) to form a vacuum state, and the reactor is injected through the gas suction port (not shown). When a predetermined alternating voltage is applied from the power supply 121 to the lower electrode, a time-varying electric field is generated between the lower electrode 112 and the upper electrode 113 to separate the reactor body into ions, negative charges, and radicals. At this time, the ions react with the thin film on the reaction panel by the applied electric field and the radicals by the applied electric field to etch the reaction panel by simultaneous action by physical collision and chemical reaction.

Particularly, reactive ion etching is mainly performed by ions colliding with the thin film by acceleration of electric field, thereby etching the thin film and characterized by anisotropic etching according to the direction of the electric field.

In the dry etching process, the substrate is damaged during the process. This is called arc and haze. Arc and haze is a phenomenon in which metals such as gates and sources / drains are damaged during the dry etching process, and the metals burst. As the metal explodes, the insulating film may be destroyed together. It is estimated that the damage of the substrate is affected by many variables such as the process conditions of the equipment, the equipment, the operation mode, the metal, and the like.

When the substrate is damaged, the plasma becomes unstable and damages the electrode in the form of a microdischarge, and the same type of damage occurs after the substrate is damaged.

However, in the conventional dry etching process, there was no means for judging the occurrence of damage, and thus there was no means for controlling it.

It is therefore an object of the present invention to provide a method of controlling substrate damage occurring in a plasma chamber in a dry etching process.

A substrate damage control method in a dry etching apparatus comprising a target dry etching plasma chamber and a power supply unit providing an electrode power source to the plasma chamber and having an impedance matching unit, wherein at least between the impedance matching unit and the plasma chamber are provided. Measuring one electrical parameter; And determining the occurrence of substrate damage when the value of the measured electrical parameter changes within a predetermined time or more within a predetermined range.

Preferably, the electrical parameters include voltage, current, voltage phase and current phase.

The method may further include calculating an impedance from the measured value of the electrical parameter. In the determining of the occurrence of the substrate damage, the occurrence of the substrate damage may be determined based on the calculated impedance value.

If it is determined that the substrate damage occurs, it is preferable to further include the step of stopping the power supply from the power supply.

Damage to the substrate, that is, arc and haze not only causes the damaged substrate to be defective, but also damages the electrode, thereby causing the substrate to be defective in the subsequent dry etching process. Sudden changes in current and voltage in the dry etching process indicate damage to the substrate. Thus, by observing current and voltage, damage to the substrate can be detected in real time. In addition, real-time detection of damage to the substrate allows immediate control during the process. That is, the present invention provides a method for controlling damage to a substrate while also providing a method for determining occurrence of substrate damage.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.                     

Figure 2 shows the change in current during the dry etching process over time. The arrows in the figure indicate damage to the substrate, ie arcs and haze. When the current was observed when the damage of the substrate occurred, it can be seen that there was a sudden change in a short time. From this, it can be seen that the damage of the substrate can be determined in real time by observing the change in the current.

3 shows the change in voltage during the dry etching process over time. The change in voltage has a form similar to the change in current. A portion indicated by an arrow as shown in FIG. 2 is a portion in which damage to the substrate is shown. As with the current, it can be seen that the voltage suddenly changed when the substrate was damaged. Therefore, damage to the substrate can be determined in real time by observing the phase of the voltage.

Figure 4 shows the phase change of the current with time. When damage occurs, such as current and voltage, the phase of the current also changes rapidly.

Figure 5 shows the change in impedance over time. Again, a sharp change occurs when damage to the substrate occurs.

In the above, only the current, voltage, phase of the current, and impedance are shown. However, harmonics can be used to indicate damage to the substrate.

6 is a plan view of a dry etching apparatus according to the present invention. Like the conventional dry etching apparatus shown in FIG. 1, the plasma chamber 610 and the power supply unit 620 are provided. The chamber 610 includes a receptor 611, a lower electrode 612, and an upper plate electrode 600, and the power supply unit 620 includes an impedance matching unit 622 and a power source 621. The sensor 630 is provided between the impedance matching unit 622 and the plasma chamber 610.

Sensor 630 measures electrical parameters. Electrical parameters include current, voltage, phase of current, phase of voltage, and the like, to calculate impedance using them. Although the position of the sensor 630 may be within the plasma chamber 610, it is preferable that the sensor 630 be located between the impedance matching unit 622 and the plasma chamber 610 to obtain an accurate value.

The determination unit 640 connected to the sensor 630 determines the damage of the substrate from the value measured by the sensor. As a determination method, there is a method of observing a measured value with time and determining whether a change of a predetermined range occurs within a predetermined time. For example, if a change of ± 10% occurs within 0.1 second, it is determined that the substrate has been damaged. The time and range of change used in the judgment depend on the characteristics of the dry etching apparatus, the difference in the allowable range depending on the substrate, and the type of electrical parameter. Another judgment method is to use the measured value when the damage of a board | substrate does not generate | occur | produce. That is, when damage to the substrate does not occur, the change of each electrical parameter is observed and stored, and when the measured value deviates from the stored value by more than a predetermined range, it is determined that the damage to the substrate occurs.

If the determination unit 640 determines that the substrate is damaged, the controller 650 takes measures to minimize the damage of the substrate. For example, cut off the power supply or lower the power supply voltage.

In addition, by using the above apparatus, it is possible to prevent substrate damage. That is, the determination unit 640 transmits the occurrence of the measured value to the control unit 650 when the predetermined value is not determined to determine that the substrate damage has occurred. The control unit 650 accordingly takes measures such as power off.

As described above, according to the present invention, in the dry etching process, occurrence of substrate damage can be determined in real time and measures can be taken. Therefore, defects caused by substrate damage can be reduced.

Claims (4)

A substrate damage control method in a dry etching apparatus comprising a dry etching plasma chamber and a power supply unit having an impedance matching portion and providing an electrode power source to the plasma chamber, Measuring at least one electrical parameter between the impedance matcher and the plasma chamber; Determining the occurrence of substrate damage when the value of the measured electrical parameter changes within a predetermined time or more within a predetermined range, The electrical parameters include voltage, current, voltage phase, current phase. delete The method of claim 1, Calculating an impedance from the measured value of the electrical parameter, In the determining of occurrence of substrate damage, the occurrence of substrate damage is determined based on the calculated impedance value. The method of claim 1, If it is determined that substrate damage has occurred, further comprising the step of stopping power supply from the power supply unit.

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