KR20130106022A - Apparatus for treating substrate and method for operating the same - Google Patents

Abstract

The present invention relates to a substrate processing apparatus and an operation method, and more particularly, to a substrate processing apparatus and an operation method for easily controlling the deposition rate of the thin film when manufacturing the thin film using the plasma in the reaction chamber. An embodiment of the present invention includes a reaction chamber, a gas injector for injecting raw material gas into the reaction space in the reaction chamber, a plasma power supply for applying plasma power to the gas injector, a substrate support disposed opposite to the gas injector; And a heater power supply unit for applying a heating voltage for heating the substrate support, a filter end disposed at a node between the heater power supply unit and the substrate support, and blocking an RF high frequency radiated from the substrate support, and connected to the filter end. And a variable impedance controller for controlling the plasma density in the reaction space by adjusting the impedance of the filter stage.

Description

Apparatus for treating substrate and method for operating the same}

The present invention relates to a substrate processing apparatus and an operation method, and more particularly, to a substrate processing apparatus and an operation method for easily controlling the deposition rate of the thin film when manufacturing the thin film using the plasma in the reaction chamber.

Many processes using plasma have been developed in the manufacturing process of semiconductor devices. For example, Plasma Enhanced Chemical Vapor Deposition (PECVD) using plasma has the advantage of being able to deposit at a lower temperature than the conventional deposition process because the source gas is activated and deposited on the substrate by plasma. have.

In the PECVD, after the substrate is seated on the substrate support in the chamber, the source gas is injected through the gas injection means (shower head) and RF power is applied to activate the source gas to deposit a predetermined film on the substrate. Deposition is performed on the substrate, and the by-product gas of the generated gas or source gas is discharged using an exhaust pipe formed in the chamber and an exhaust pump connected thereto. As described above, PECVD promotes thin film deposition by enabling a chemical reaction at a low temperature by activating a source gas using plasma to enhance reactivity.

Meanwhile, in the case of PECVD equipment, a method of changing parameters such as gas amount and pressure is used to adjust the deposition rate of a film deposited on a substrate. However, since the plasma reacts nonlinearly to small process condition changes, even if parameters such as gas amount and pressure are changed, it is difficult to obtain a desired film deposition rate. In addition, since the plasma reacts sensitively to parameter changes such as gas amount and pressure to change both physical and chemical properties, it is difficult to produce a desired film quality. In other words, the process parameter change method may cause physical and chemical changes of plasma that are sensitive to external factors, which may greatly affect the existing film quality, making the process more difficult. Therefore, in the field, the selected process is not changed very well. Therefore, there is a need for other control methods that are simpler and more accurate than current methods for controlling the film deposition rate, that is, the control methods of gas amount, pressure, gap, and the like.

Korean Registration No. 755116

An object of the present invention is to control the deposition rate of the thin film deposited on the substrate in the reaction chamber. Namely, it is to efficiently control the thickness of the film deposited on the substrate.

Another object of the present invention is to provide a simple and accurate thin film deposition rate control method for controlling the deposition rate of a thin film deposited on a substrate.

An embodiment of the present invention includes a reaction chamber, a gas injector for injecting raw material gas into the reaction space in the reaction chamber, a plasma power supply for applying plasma power to the gas injector, a substrate support disposed opposite to the gas injector; And a heater power supply unit for applying a heating voltage for heating the substrate support, a filter end disposed at a node between the heater power supply unit and the substrate support, and blocking an RF high frequency radiated from the substrate support, and connected to the filter end. And a variable impedance controller for controlling the plasma density in the reaction space by adjusting the impedance of the filter stage.

The filter stage may include at least one of a resistor (R) -capacitor (C) filter circuit, an inductor (L) -capacitor (C) filter circuit, and a resistor (R) -inductor (L) -capacitor (C) filter circuit. Low pass filter. Also, the variable impedance controller changes the value of the variable inductor or variable capacitor.

In another aspect, the present invention provides a process for preparing a substrate, loading the substrate to a substrate support in the reaction chamber, supplying a gas to the reaction space in the reaction chamber and generating a plasma, And controlling the thickness of the thin film deposited on the substrate by changing the plasma density inside the reaction space by adjusting the impedance of the filter stage to block the radiated RF high frequency.

In addition, when the deposition rate of the thin film deposited on the substrate is increased, the impedance value of the filter stage is reduced. In addition, when lowering the deposition rate of the thin film deposited on the substrate, the impedance value of the filter stage is increased.

According to the embodiment of the present invention, the deposition rate of the thin film may be easily controlled by adjusting the impedance of the filter terminal connected to the substrate support for supporting and heating the substrate. In addition, the deposition rate of the film can be accurately controlled by adjusting the plasma state by adjusting the hardware impedance without changing the gas amount, pressure, gap, and the like. In addition, it is possible to stably control the deposition rate of the film without physical and chemical changes of the film.

1 is a block diagram of a substrate processing apparatus according to an embodiment of the present invention.
2 is a diagram showing impedance and voltage when configuring the substrate processing apparatus according to the embodiment of the present invention.
3 is a graph showing an experimental result graph showing the change in the voltage V ₂ according to the change in the impedance of the filter stage according to an embodiment of the present invention.
4 is a graph showing an experimental result graph showing a change in the thickness of the deposited film according to the impedance change of the filter stage according to the embodiment of the present invention.
5 is a flowchart illustrating a process of adjusting the deposition rate of a film according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

In the following description, the RF power supply unit will be described as an example of the power supply unit, but various power supply units such as a DC voltage may be applied.

1 is a block diagram of a substrate processing apparatus according to an embodiment of the present invention, Figure 2 is a diagram showing the impedance and voltage when configuring the substrate processing apparatus according to an embodiment of the present invention.

The reaction chamber 100 provides a predetermined reaction region and keeps it airtight to deposit a single thin film, a plurality of thin films of the same kind, or a composite film of different kinds on a substrate. The reaction chamber 100 includes a reaction part having a predetermined space, including a substantially circular flat part and a side wall part extending upwardly from the planar part, and positioned on the reaction part in a substantially circular shape to keep the reaction chamber 100 airtight. It may include a cover. Of course, the reaction unit and the cover may be manufactured in various shapes other than a circle, for example, may be manufactured in a shape corresponding to the shape of the substrate 10.

The gas injector 120 is installed at a position facing the substrate support 110 in the upper portion of the reaction chamber 100, and injects the raw material gas into the lower side of the reaction chamber 100. The upper part of the gas injector 120 is connected to the source gas source, and the lower part of the gas injector 120 is formed with a plurality of injection holes for injecting the source gas into the substrate 10. The gas injector 120 may be manufactured in a substantially circular shape, but may also be manufactured in the shape of the substrate 10. In addition, the gas injector 120 may be manufactured with the same size as the substrate support 110. In addition, the gas injector may have various shapes such as a showerhead shape, a nozzle shape, and the like.

On the other hand, the source gas injected from the gas injector 120 is activated and deposited on the substrate 10, the power provided in the form of RF provided from the RF plasma power supply 200 for this activation (hereinafter, 'RF plasma voltage ') Is applied to the gas injector 120. The source gas between the gas injector and the substrate support is activated by the RF plasma voltage applied to the gas injector to deposit a film on the substrate.

The RF plasma power supply unit 200 is installed to excite the source gas into the plasma state by using the plasma. The RF plasma power supply 200 may be implemented in a single mode of one RF power source or in a dual mode applied to two RF power sources. RF plasma power supply 200 is a capacitive coupling plasma (CCP) for supplying a plasma generating voltage to the reaction space which is the deposition space of the substrate between the gas injector and the substrate support on the substrate of the reaction chamber 100, the plasma state; Capacitively Coupled Plasma). In the exemplary embodiment of the present invention, the capacitively coupled plasma (CCP) method is exemplified, but the present invention is not limited thereto and may be implemented by an inductively coupled plasma (ICP) method.

The matcher 400 is a circuit for impedance matching to remove the return loss, and is located between the RF plasma power supply corresponding to the power supply and the gas injector corresponding to the load. For reference, impedance matching refers to the impedance design so that the impedance of both is the same so that there is no reflection loss when connecting the power supply and the load circuit.

The substrate support 110 is provided below the reaction chamber 100 and is installed at a position facing the gas injector 120. The substrate support 110 may be provided with, for example, an electrostatic chuck so that the substrate 10 introduced into the reaction chamber 100 may be seated. In addition, the substrate support 110 may be provided in a substantially circular shape, but may be provided in a shape corresponding to the shape of the substrate 10 and may be made larger than the substrate 10. A substrate elevator (not shown) for moving the substrate support 110 up and down is provided below the substrate support 110. The substrate lifter moves the substrate support 110 to approach the gas injector 120 when the substrate 10 is seated on the substrate support 110.

In order to heat the substrate support 110, the heating element 111 may be embedded in the substrate support or positioned in contact with the substrate support lower portion. The heating element is implemented by a heater or the like to heat the substrate support 110 by heating to a predetermined temperature, so that a predetermined film, for example, an etch stop film and an interlayer insulating film by a gaseous source and a liquid source, may be used as a substrate ( 10) to be easily deposited on. Since the heating element is buried, in contact with, or adjacent to the substrate support, hereinafter, it is assumed that there is no difference between the voltage applied to the heating element and the voltage applied to the substrate support. Therefore, hereinafter, it is assumed that the voltage measured by the heating element is the same as the measured voltage of the substrate support.

The RF heater power supply unit 300 generates an RF voltage and applies the generated voltage to the heating element, thereby generating the heating element. To this end, one node of the RF heater power supply 300 is connected to ground (GND) and the other node is connected to the heating element.

The filter stage 500 is implemented as a low pass filter (LPF) to block the high frequency RF radiated to the outside through the substrate support when RF plasma power is applied. When RF plasma is applied between the gas injector 120 and the substrate support 110, high frequency RF may be radiated through the substrate support 110. Such an unintended RF high frequency may cause a mass flow controller (MFC). This affects the control operation of the chamber peripheral device. Therefore, the filter stage 500 is connected between the substrate support 120 and the RF heater power supply 300 to block high frequency RF radiated through the substrate support 120.

To this end, the filter stage may include at least one of a resistor (R) -capacitor (C) filter circuit, an inductor (L) -capacitor (C) filter circuit, and a resistor (R) -inductor (L) -capacitor (C) filter circuit. To pass the low frequency band and cut off the high frequency band. The resistor R, the inductor L, and the capacitor C may be implemented as a variable element to change a desired resistance value, an inductor value, and a capacitor value. For example, in the case of the variable resistor, the resistance value may be changed by sliding the metal body over the resistor, or the contact may be contacted in turn to change the resistance value by raising a terminal. Similarly, a known variable capacitor, variable inductor can be used to change the value of the capacitor (capacitance) or the value of the inductor (inductance).

The impedance Z ₂ of the filter stage 500 is a series-parallel combination of an impedance Z _R of a resistor, an impedance Z _{C of a} capacitor, and an impedance Z _{L of an} inductor.

Resistance Impedance (Z _R ) = R

Inductor impedance (Z _L ) = jωL

Capacitor Impedance (Z _C ) = 1 / jωC

Impedance of the filter stage (Z ₂ ) = Z _R + Z _C + Z _L = R + jωL + 1 / jωC

The variable impedance controller 600 changes the value of the impedance Z ₂ of the filter stage, and may change the impedance of the filter stage by changing the resistance of the filter stage, the value of the capacitor, and the value of the inductor. Accordingly, the variable impedance controller changes Z _R , Z _C , and Z _L by varying the values of resistors, capacitors, and inductors in accordance with predesigned impedance values.

The variable impedance controller 600 decreases the value of the impedance Z _{2 applied} to the filter stage in order to increase the film deposition rate deposited on the substrate. Reduction of the impedance (Z ₂ ) across the filter stage reduces the voltage across the filter stage (V ₂ ) by Ohm's law (V = ZI), which is the voltage across the reaction space by the voltage division law. The reaction space voltage (V _A -V _B ) is increased. An increase in the reaction space voltage (V _A -V _B ) results in an increase in the plasma density in the reaction space, resulting in an increase in the deposition rate of the film deposited on the substrate.

On the contrary, the variable impedance controller 600 increases the impedance value Z ₂ when it is desired to lower the film deposition rate deposited on the substrate. Increasing the value of the impedance (Z ₂ ) applied to the filter stage 500 increases the voltage (V ₂ ) applied to the filter stage, thereby reducing the reaction space voltage (V _A -V _B ) by the voltage division law. do. Reduction of the reaction space voltage (V _A -V _B ) results in a decrease in the plasma density in the reaction space, resulting in a decrease in the deposition rate of the film.

Hereinafter, an example of the change in voltage applied to the reaction space due to the change in the impedance of the filter stage will be described in detail.

When the sum of the impedances applied to the gas injector 120, the reaction space, and the substrate support 110 is Z ₁ , and the impedances applied to the filter stage 500 are Z ₂ , the voltage applied to the entire circuit as shown in FIG. 2. Is a voltage applied from the RF plasma power supply unit 200, a voltage applied to the matcher 400, a voltage V ₁ applied to the Z ₁ impedance, a voltage V ₂ applied to the Z ₂ impedance, and an RF heater power supply unit. The voltage and ground voltage GND can be viewed as a series circuit configuration. For reference, the impedance voltage of the variable impedance controller is to be ignored, and the reaction space voltage V _A -V _B corresponds to the voltage V ₁ applied to the Z ₁ impedance.

In an embodiment of the present invention, the reaction space voltage (V _A -V _B = V ₁ ) may be adjusted by adjusting the voltage V ₂ applied to the filter stage by adjusting the impedance Z _{2 of} the filter stage. Such a change in the reaction space voltage (V _A -V _B = V ₁ ) can change the plasma density in the reaction space to control the film deposition rate of the substrate. Since the value of V ₁ + V ₂ due to the plasma voltage and the heating element voltage is constant, if the V ₂ voltage is changed by adjusting the impedance of the filter stage, the reaction space voltage (V _A -V) applied to Z ₁ due to the voltage division law _B = V ₁ ) is different. Current is reduced is because the schedule is increased when V ₁ V _2, V ₂ By contrast, an increase in V ₁ utilizes the properties of a voltage divider which is small.

The change in the reaction space voltage (V _A -V _B = V ₁ ) causes the plasma density in the reaction space to vary, resulting in a change in the deposition rate of the film. For example, increasing the plasma generation voltage increases the plasma density in the reaction space, or increases the deposition rate of the film due to the reduction of the DC self bias. Therefore, the film thickness increases due to the increase in the deposition rate of the film.

As a result, by varying the impedance Z ₂ across the filter stage, the V ₂ voltage across the filter stage is also changed by Ohm's law (V = ZI), and the response space is changed by the voltage division law according to the V ₂ voltage change. The voltage (V _A -V _B = V ₁ ) also changes, resulting in a change in the deposition rate of the film deposited on the substrate.

3 is a graph showing an experimental result graph showing the change in the voltage V ₂ according to the change in the impedance of the filter stage according to an embodiment of the present invention.

Referring to FIG. 3, when the filter stage is implemented with L ₁ and L _{2, which} are inductors adjacent to the heating element, when two inductors L ₁ and L ₂ are configured in series or in parallel, the horizontal axis is represented by L ₁ and L ₂ . Inductance value is shown. When and matching tile la the voltage across the voltage across the nodes to a node between V _A, a filter stage and the substrate support between the gas injector V _B, and the vertical axis shows the effective value (V _eff) value of the V _B / V _A. The graph shows that when the value of inductance changes, the value of V _B / V _A changes, and the value of V _A is almost constant RF voltage generated by the RF plasma generating voltage, so that the value of V _B changes. Can be. Since the voltage across the reaction space in the chamber is V _A (constant) -V _B (change), in the end, the change in inductance results in a change in the voltage across the reaction space in the chamber, affecting the plasma density in the reaction space This results in a change in the deposition rate of the film. For reference, since the output of the power supply is constant so that the current is constant, the impedance of Z ₂ corresponds to the Y-axis ratio on the graph. As a result, the impedance of Z ₂ changes according to the change of L ₁ and L ₂ , and the change can be confirmed by the change of V _B voltage.

4 is a graph showing an experimental result graph showing a change in the thickness of the deposited film according to the impedance change of the filter stage according to the embodiment of the present invention.

Referring to FIG. 4, when the filter stage is implemented as L ₁ and L _{2, which} are inductors adjacent to the heating element, when two inductors L ₁ and L ₂ are configured in series or in parallel, the horizontal axis is represented by L ₁ and L ₂ . Inductance value is shown. And the vertical axis shows the deposition thickness of the film according to the change in inductance. There voltage applied to the reaction space of the chamber is represented by V _A -V _B, referring to the graph, which is a result of progress in a process recipe (recipe), such as for the same time have an effect on the plasma voltage was measured in the Z ₂ and An inverse deposition rate occurs. For reference, since the power P is expressed as voltage (V) * current (I), since the current flowing in series Z ₁ and Z ₂ is constant, the change in voltage (V ₁ , V ₂ ) applied to each impedance is constant. Will immediately change the applied state of the plasma resulting in a change in the applied power.

5 is a flowchart illustrating a process of adjusting the deposition rate of a film according to an embodiment of the present invention.

First, a process of preparing a substrate is performed (S51). The substrate is loaded onto the substrate support in the reaction chamber (S52). Thereafter, a plasma is generated inside the reaction chamber (S53). The thickness of the film formed on the substrate is controlled by changing the impedance value of the filter stage filtering the voltage for heating the substrate support (S54).

By controlling the voltage across the filter stage by adjusting the impedance Z _{2 of} the filter stage, the reaction space voltage between the gas injector and the substrate support can be adjusted. Such a change by adjusting the reaction space voltage may change the plasma density in the reaction space to control the film deposition rate of the substrate.

When the current in the reaction space is constant, the change in voltage causes different plasma densities in the reaction space to change the deposition rate of the film. For example, increasing the plasma generation voltage increases the plasma density in the reaction space, or increases the deposition rate of the film due to the reduction of the DC self bias. Therefore, the film thickness increases due to the increase in the deposition rate of the film.

When the deposition rate of the film deposited on the substrate is increased, the impedance value of the filter stage is decreased, and when the deposition rate of the film deposited on the substrate is decreased, the control is performed to increase the impedance value of the filter stage.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

10: substrate 100: reaction chamber
110: substrate support 120: gas injector
200: RF plasma power supply 300: RF heater power supply
400: matcher 500: filter stage
600: variable impedance control unit

Claims (6)

A reaction chamber;
A gas injector for injecting a raw material gas into the reaction space in the reaction chamber;
A plasma power supply unit applying plasma power to the gas injector;
A substrate support disposed opposite the gas ejector;
A heater power supply for applying a heating voltage for heating the substrate support;
A filter stage positioned at a node between the heater power supply unit and a substrate support and blocking RF high frequency radiated from the substrate support;
A variable impedance controller connected to the filter stage and controlling the plasma density in the reaction space by adjusting the impedance of the filter stage;
Substrate processing apparatus comprising a. The filter stage of claim 1, wherein the filter stage includes a resistor (R) -capacitor (C) filter circuit, an inductor (L) -capacitor (C) filter circuit, and a resistor (R) -inductor (L) -capacitor (C) filter circuit. Substrate processing apparatus is a low-pass filter implemented in at least one of. The substrate processing apparatus of claim 2, wherein the variable impedance controller changes a value of the variable inductor or the variable capacitor. Preparing a substrate;
Loading the substrate onto a substrate support in the reaction chamber;
Supplying gas to a reaction space in the reaction chamber and generating a plasma;
Controlling the thickness of the thin film deposited on the substrate by changing the plasma density in the reaction space by adjusting the impedance of the filter stage blocking the RF high frequency radiated from the substrate support;
≪ / RTI > The substrate treating method of claim 4, wherein when increasing the deposition rate of the thin film deposited on the substrate, the impedance value of the filter stage is reduced. The substrate processing method of claim 4, wherein when the deposition rate of the thin film deposited on the substrate is lowered, an impedance value of the filter stage is increased.

Images