KR100728164B1 - Etching apparatus and method of a large size substrate - Google Patents

Abstract

The present invention provides an etching apparatus and an etching method of a large-area substrate which can improve the etching uniformity by effectively compensating the etching uniformity resulting from the antenna form of the inductively coupled plasma etching apparatus. An etching apparatus according to an embodiment of the present invention includes a process chamber in which plasma is generated. A spiral antenna is provided above the process chamber, and a substrate support for supporting a large area substrate is provided below the process chamber. In the etching apparatus of the above configuration, the stock etching step is performed by an inductively coupled plasma etching process using a spiral antenna, and after the etching end point is detected by an endpoint detector, the high frequency power applied to the spiral antenna is cut off, thereby electrostatically coupled plasma etching process. By the over-etching step is performed.

Large area substrates, etching, uniformity, electrostatic coupling, inductive coupling, plasma,

Description

Etching Apparatus and Etching Method of Large-area Substrate {ETCHING APPARATUS AND METHOD OF A LARGE SIZE SUBSTRATE}

1 is a schematic configuration diagram of a large-area substrate etching apparatus according to an embodiment of the present invention.

FIG. 2 is a process block diagram illustrating an etching method using the etching apparatus of FIG. 1.

3 and 4 are conceptual diagrams showing a stock angular step and a transient etching step which are the main process steps of FIG. 2.

The present invention relates to an etching apparatus and an etching method of a large area substrate, and more particularly to an etching apparatus and an etching method of a large area substrate that can improve the etching uniformity.

In the technical field where a fine pattern should be formed in a flat panel display or a semiconductor wafer, plasma is generated to perform various surface treatment processes such as dry etching, chemical vapor deposition, and sputtering. Recently, in order to achieve cost reduction and yield improvement, BACKGROUND OF THE INVENTION The size of display substrates and wafers for semiconductor devices tends to increase in size, and thus the size of etching apparatuses for processing large substrates or wafers is increasing.

Among the etching apparatuses, widely used are inductively coupled plasma generators.

The inductively coupled plasma generator includes a chamber in which a plasma is generated, which includes a gas inlet for supplying a reaction gas, a vacuum pump and a gas outlet for maintaining a vacuum inside the chamber and discharging the gas generated during the reaction. It is. In addition, a chuck for placing a sample such as a glass substrate or a wafer is provided inside the chamber, and an antenna to which a high frequency power source is connected is provided at the top of the chamber. An insulating plate is provided between the antenna and the chamber to reduce capacitive coupling between the antenna and the plasma to help transfer energy from high frequency power to the plasma by inductive coupling.

In the inductively coupled plasma generator having such a structure, the inside of the chamber is initially evacuated to be evacuated by a vacuum pump, and then a reactive gas for generating plasma is introduced from the gas inlet and maintained at a required pressure. Subsequently, high frequency power is applied to the antenna from a high frequency power supply.

In this way, when a high frequency power is applied to the antenna, a magnetic field that changes in time perpendicular to the plane of the antenna is formed, and the magnetic field that changes in time forms an induction electric field inside the chamber, and the induction electric field heats electrons to induce the antenna and induction. Generate a plasma coupled to the castle. The electrons collide with the surrounding neutral gas particles to generate ions and radicals, which are used for plasma etching and deposition. In addition, when power is applied to the chuck from a separate high frequency power source, it is also possible to control the energy of ions incident on the sample.

Therefore, when etching an object, such as an oxide film, a metal wiring layer, or a metal wiring layer of a flat panel display device, using an inductively coupled plasma generator having the above-described configuration, conventionally, the stock angle (first etching process) is used. ) And the end point is detected using an end point detector (EPD: End Point Detector) attached to the etching chamber while performing the stock etch step, and transient etching is performed under the same process conditions as the stock etch step (second etching process). Proceed.

However, when etching an etching target on a large area substrate using an inductively coupled plasma generator, the following problems occur.

In the inductively coupled plasma generator, since each winding constituting the spiral antenna is connected in series, the amount of current flowing in each winding becomes constant. In this case, it is difficult to control the distribution of the induced electric field, which causes the loss of ions and electrons in the inner wall of the chamber. The central part has a high density and it is difficult to prevent the density of the plasma from being lowered near the inner wall of the chamber. Therefore, it is extremely difficult to keep the density of the plasma uniform.

In addition, since each winding of the antenna is connected in series, the voltage drop caused by the antenna is increased, thereby increasing the influence of capacitive coupling with the plasma. Therefore, the power efficiency is lowered and it is also difficult to maintain the uniformity of the plasma.

Therefore, in order to improve the uniformity, conventionally, a thicker dielectric is used or a antenna is modified in a dome shape, but this has a limitation in that it is difficult to apply to a process such as oxide etching and the structure.

The present invention has been made to solve the above problems, and an object thereof is to provide an etching apparatus and an etching method suitable for etching an etch target of a large-area substrate.

The present invention to achieve the above object,

Process chamber where plasma is generated, Spiral antenna installed on the upper side of the process chamber, Substrate support installed in the lower side of the process chamber to support the large area substrate, High frequency matching network connected to the spiral antenna and the substrate support, Spiral antenna and substrate support An inductively coupled plasma etching process is performed in the stock etching step for etching the high frequency power source applying high frequency power to the substrate, an endpoint detector for detecting an etching end point, and an etching target of the large-area substrate, and an electrostatic coupling plasma etching process in the transient etching step. It provides an etching apparatus of a large area substrate comprising a control unit for controlling the on / off of the high frequency power applied to the spiral antenna to proceed.

The substrate support is preferably installed to enable vertical movement.

The etching apparatus having such a configuration can be used to form a metal wiring layer of a thin film transistor used in a flat panel display such as an organic light emitting display and a liquid crystal display, and also an oxide film and / or a copper wiring film used in a conventional semiconductor device. It can also be used to etch.

Since the metal wiring layer of the thin-film transistor in the above-described flat panel display device is a molybdenum compound is typically used, when an example describes a case of etching the metal wiring layer made of a molybdenum compound, the stock a SF ₆ / O _2, when to proceed through each step in the reaction gas High frequency power of 2 to 3 kHz to the helical antenna at a frequency of 13.56 MHz, 100 to 3 kHz to the substrate support at a frequency of 13.56 MHz, and maintain the process chamber at a pressure of 5 to 50 mT. do.

In the transient etching step, CL ₂ / O ₂ is used as a reaction gas, and power of 800 to 2 kHz is applied to the substrate support at a frequency of 13.56 MHz, and the process chamber is maintained at a pressure of 70 to 90 mT. .

In the case of etching the object to be etched using the etching apparatus of the above configuration, in the stock etching step, the inductively coupled plasma etching process is performed by applying high frequency power to the spiral antenna and the substrate support, and in the transient etching step after the etching end point is detected. In the state in which the high frequency power of the spiral antenna is cut off, the high frequency power is applied only to the substrate support to perform the electrostatic coupled plasma etching process.

Specifically, the etching method for etching the large area substrate of the present invention,

Performing the stock etch step using an inductively coupled plasma etching process, detecting an etch endpoint using an endpoint detection device, and ending the inductively coupled plasma etching process and then using the electrostatically coupled plasma etching process. Including the step of proceeding.

Then, the transient etching step is adjusted to 100 ~ 300% compared to the process time of the stock angle step, the transient etching step is performed in a state of cutting off the high frequency power applied to the streamlined antenna.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a schematic configuration diagram of a large-area substrate etching apparatus according to an embodiment of the present invention, FIG. 2 is a process block diagram illustrating an etching method using the etching apparatus of FIG. 1, and FIGS. 3 and 4 are FIGS. This is a conceptual diagram showing the stock angular stage and the transient etch stage, which are the main process stages.

As shown, the etching apparatus of the large-area substrate according to the embodiment of the present invention includes a process chamber 10 in which plasma is generated.

The process chamber 10 is provided with a gas inlet 12 through which a reaction gas flows, and a spiral antenna 14 is provided above the chamber 10.

In addition, a chuck 18 for supporting the large-area substrate 16 is provided below the chamber 10, and the chuck 18 is installed to be able to move up and down by a moving means such as a cylinder 20. .

High frequency matching networks 22a and 22b are connected to the spiral antenna 14 and the chuck 18, respectively, and high frequency power supplies 24a and 24b to which high frequency power is applied to each of the networks 22a and 22b.

Each of the high frequency matching networks 22a and 22b is connected to the controller 26, and an endpoint detector 28 is connected to the controller 26 for detecting an etch endpoint.

In FIG. 1, reference numeral 30 denotes a clamp for holding a large area substrate, and reference numeral 32 denotes a plasma generated inside the chamber.

A method of etching a large area substrate using an etching apparatus having such a configuration will be described.

In an etching method according to an embodiment of the present invention, an inductively coupled plasma etching process having a poor etching uniformity but a high etching rate is sequentially performed, and an electrostatically coupled plasma etching process having a lower etching rate but better etching uniformity than the inductively coupled plasma etching process. It is characterized in that the implementation.

First, a large area substrate 16 provided with an etching object is prepared.

The etching target is a molybdenum compound used as a metal wiring layer of a thin film transistor in a flat panel display such as an organic light emitting display or a liquid crystal display, or an oxide film forming an insulating film in a semiconductor device, or a copper film used as a metal wiring layer. Can be.

In the following description, the etching target is a molybdenum compound used as a metal wiring layer in a thin film transistor of an organic light emitting diode display, but the present invention is not limited thereto.

When the large-area substrate 16 is seated on the chuck 18 installed inside the process chamber 10, the large-area substrate 16 is used as a metal wiring layer in an etch target provided on the large-area substrate 16, for example, a thin film transistor of an organic light emitting display device. An etching process for etching the molybdenum compound 34 is performed.

Although not shown, a mask pattern, for example, a photoresist pattern, is formed on the compound to etch the molybdenum compound.

First, when a vacuum pump (not shown) is operated to evacuate the inside of the process chamber 10, a reaction gas for generating the plasma 32 is introduced from the gas inlet 12 and maintained at a required pressure.

Here, SF ₆ / O ₂ is used as the reaction gas, and the inside of the chamber 10 is maintained at a pressure of 5 to 50 mTorr.

Subsequently, high frequency power of 2 to 3 kW is applied to the spiral antenna 14 at a frequency of 13.56 MHz from the high frequency power supply 24a.

When high frequency power is applied to the antenna 14 as described above, a magnetic field that changes in time perpendicular to the plane of the antenna 14 is formed, and the magnetic field that changes in time forms an induction electric field in the chamber 10 and induces it. The electric field heats the electrons to generate a plasma 32 inductively coupled to the antenna 14. As such, the electrons collide with the surrounding neutral gas particles to generate ions, radicals, and the like, which are used to etch the molybdenum compound on the substrate 16.

Further, power of 100 to 3 kW is applied to the substrate 16 at a frequency of 13.56 MHz from the high frequency power supply 24b to control energy of ions incident on the molybdenum compound.

The stock etch step by this inductively coupled plasma etching process continues until the etch endpoint is detected by the endpoint detector 28.

Subsequently, when an end point detection signal is input from the end point detector 28 to the control unit 26, the control unit 26 cuts off the high frequency power applied to the spiral antenna 14 through the high frequency matching network 22a and transients. The etching step is performed, and the above-described transient etching step is performed under the following process conditions.

The transient etching step is performed by an electrostatically coupled plasma etching process, in which CL ₂ / O ₂ is used as a reaction gas, and power of 800 to 2 GHz is applied to the substrate support 18 at a frequency of 13.56 MHz. The process chamber 10 is maintained at a pressure of ˜90 mTorr.

This transient etching step is adjusted to 100-300% of the processing time of each stock step.

In the above, the case where the molybdenum compound is etched has been described as an example. However, the present invention can also be used to form an oxide film or a copper wiring layer of a semiconductor device.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, the etching apparatus and the etching method of the large-area substrate according to the embodiment of the present invention proceed with the stock etching step by using the inductively coupled plasma etching process, and in the subsequent etching step, the etching uniformity is higher than the inductively coupled plasma etching process. An excellent electrostatically coupled plasma etching process is used.

Therefore, the etching uniformity can be improved without significantly lowering the etching rate, so that the etching target of the large-area substrate can be etched with good etching uniformity.

Claims (9)

A process chamber in which plasma is generated; A spiral antenna installed on the upper side of the process chamber; A substrate support installed in the lower side of the process chamber to support a large area substrate; A high frequency matching network connected to the spiral antenna and a substrate support; A high frequency power supply for applying high frequency power to the spiral antenna and the substrate support; An endpoint detector for detecting an etch endpoint; And Control unit for controlling the on / off of the high frequency power applied to the spiral antenna and the substrate support Including; In the stock angle step for etching the etch target of the large-area substrate, both the helical antenna and the high frequency power applied to the substrate support are 'on' so that an inductively coupled plasma etching process is performed, and in the transient etching step, the spiral antenna is applied to the spiral antenna. An apparatus for etching a large-area substrate in which a high frequency power applied to the substrate support is 'on' while a high frequency power is 'off' to perform an electrostatic coupling plasma etching process. The method of claim 1, Etching apparatus of a large area substrate that the substrate support is installed to enable the vertical movement. The method according to claim 1 or 2, Etching apparatus of a large-area substrate, characterized in that the etching target is a molybdenum compound. The method of claim 3, wherein In each of the stock stages, SF ₆ / O ₂ is used as the reaction gas, and high frequency power of ₂ to ₃ GHz is applied to the spiral antenna at a frequency of 13.56 MHz, and power of 100 to 3 GHz is applied to the substrate support at a frequency of 13.56 MHz. An apparatus for etching a large-area substrate which is applied to and holds a process chamber at a pressure of 5 to 50 mTorr. The method of claim 3, wherein In the transient etching step, CL ₂ / O ₂ is used as a reaction gas, and a power of 800 to 2 GHz is applied to the substrate support at a frequency of 13.56 MHz, and a large area substrate is maintained at a pressure of 70 to 90 mTorr. Etching device. An etching method for etching an etching target of a large area substrate, Performing a stock etch step using an inductively coupled plasma etch process; Detecting an etch endpoint using an endpoint detection device; And Proceeding the transient etching step using an electrostatic coupled plasma etching process Etching method of a large-area substrate comprising a. The method of claim 6, In the stock angle step, high frequency power is applied to the spiral antenna and the substrate support, and the inductively coupled plasma etching process is performed. In the transient etching step after the etching end point is detected, high frequency power is applied only to the substrate support in a state where the high frequency power of the spiral antenna is cut off. Method of etching a large-area substrate is subjected to the electrostatic coupling plasma etching process by applying. The method of claim 7, wherein The over-etching step is a large-area substrate etching method that is adjusted to 100 to 300% compared to the process time of each stock step. The method of claim 7, wherein The overetching step is a large-area substrate etching method performed in a state in which the high frequency power applied to the streamline antenna is cut off.

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