JP7801566B2 - Plasma processing equipment - Google Patents

Description

This disclosure relates to a plasma processing apparatus.

Plasma processing equipment is known that generates inductively coupled plasma within a vacuum chamber using an antenna placed within the chamber. Depending on the type of plasma processing equipment, the generated plasma is used to perform a specific plasma process, such as film formation by chemical vapor deposition or sputtering, or etching, on a substrate or other workpiece.

Japanese Patent Application Publication No. 8-8232

In plasma processing equipment, it is important to properly control the behavior of charged particles contained in the plasma generated during plasma processing within the vacuum vessel (processing chamber). This is because the quality of plasma processing is affected by the behavior of these charged particles relative to the workpiece.

However, the above-mentioned conventional plasma processing apparatus did not disclose how to appropriately control the movement of charged particles.

This disclosure has been made in consideration of the above-mentioned problems, and aims to provide a plasma processing apparatus that can appropriately control the behavior of charged particles.

To solve the above problem, one aspect of the present disclosure provides a plasma processing apparatus equipped with a processing chamber, which includes a stage on which an object to be processed is placed, an antenna for generating inductively coupled plasma within the processing chamber, and an internal electrode to which a predetermined potential is applied.

One aspect of the present disclosure provides a plasma processing apparatus that can appropriately control the behavior of charged particles.

1 is a diagram illustrating a configuration of a plasma processing apparatus according to a first embodiment of the present disclosure. 2A to 2C are diagrams illustrating a specific example of the configuration of the internal electrode shown in FIG. 1 . 3A and 3B are diagrams illustrating the function of the internal electrodes. FIG. 10 is a diagram illustrating a configuration of a plasma processing apparatus according to a second embodiment of the present disclosure.

[Embodiment 1]
Hereinafter, a first embodiment of the present disclosure will be described in detail with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram illustrating the configuration of a plasma processing apparatus 1 according to the first embodiment of the present disclosure. Fig. 2 is a diagram illustrating a specific configuration example of the internal electrode 8 shown in Fig. 1.

In the following explanation, a plasma processing apparatus that forms a film on a substrate H1 to be processed by plasma CVD (Chemical Vapor Deposition) using inductively coupled plasma will be used as an example of plasma processing. However, the plasma processing apparatus 1 of the present disclosure can also be applied to a plasma processing apparatus that performs, for example, a sputtering process to form a predetermined substance on a substrate H1 to be processed as a workpiece. The plasma processing apparatus 1 of the present disclosure can also be applied to a plasma processing apparatus that performs an etching process or an ashing process to remove a predetermined substance from a substrate H1 to be processed.

<Plasma processing apparatus 1>
1, the plasma processing apparatus 1 of the first embodiment includes a stage 3 on which a substrate H1 to be processed is placed as an object to be processed. The plasma processing apparatus 1 includes a processing chamber 2, and within the processing chamber 2, a predetermined plasma processing is performed on the substrate H1 to be processed placed on the stage 3. The plasma processing apparatus 1 also includes a load lock chamber (not shown) for transferring the substrate H1 to and from the outside of the plasma processing apparatus 1.

The plasma processing apparatus 1 also includes a control unit (not shown) that controls each part of the plasma processing apparatus 1. This control unit is a functional block that includes, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc., and controls each component in accordance with information processing.

The substrate H1 to be processed is placed on the stage 3 of the processing chamber 2 from the load lock chamber by a transport mechanism (not shown). The substrate H1 to be processed is then transported from the stage 3 of the processing chamber 2 into the load lock chamber by the transport mechanism. The substrate H1 to be processed may be, for example, a glass substrate or a synthetic resin substrate used in liquid crystal panel displays, organic EL (Electro Luminescence) panel displays, etc. The substrate H1 to be processed may also be a semiconductor substrate used for various applications. The plasma processing apparatus 1 forms a predetermined coating, such as a barrier (moisture-proof) film, on the substrate H1 to be processed by the predetermined plasma processing.

<Processing chamber 2>
The processing chamber 2 is constructed using a grounded vacuum container, and while the interior of the vacuum container is maintained at a predetermined vacuum level, a predetermined plasma processing is performed on the substrate H1 to be processed under the control of the control unit. In the plasma processing apparatus 1 of this embodiment 1, the stage 3 is also grounded. In addition to this explanation, it is preferable to also control the potential of the stage 3, as will be described in embodiment 2 below, in order to more appropriately perform the plasma processing.

The processing chamber 2 is also equipped with a temperature sensor (not shown) that detects the temperature of the stage 3, and the detection results of this temperature sensor are output to the control unit. The control unit then performs feedback control of the temperature of the stage 3 using the input detection results of the temperature sensor, thereby controlling the stage 3 to maintain a predetermined set temperature during the plasma processing.

The processing chamber 2 is also provided with a processing gas supply unit (not shown) that introduces processing gas, including the film-forming gas for the above-mentioned coating, into the processing chamber 2, corresponding to the above-mentioned specified plasma processing, so that the plasma processing is performed in an atmosphere of the processing gas. The processing gas is, for example, argon, hydrogen, nitrogen, silane, or oxygen.

<Antenna 4>
An antenna 4 is provided above the stage 3 inside the processing chamber 2 to generate inductively coupled plasma inside the processing chamber 2. That is, the plasma processing apparatus 1 of the present disclosure generates inductively coupled plasma by passing a high-frequency current through the antenna 4 to generate a high-frequency induction field near the antenna 4. The antenna 4 is provided, for example, linearly above the substrate H1 to be processed. Both ends of the antenna 4 are airtightly extended to the outside of the processing chamber 2. Furthermore, an impedance adjustment unit 5 and an impedance adjustment unit 7 are connected to one end and the other end of the antenna 4, respectively.

The impedance adjustment unit 5 includes a matching circuit, and one end of the antenna 4 is connected to the power supply 6 via the impedance adjustment unit 5. The impedance adjustment unit 7 includes a variable capacitor. The other end of the antenna 4 is grounded via the impedance adjustment unit 7.

The power supply 6 supplies high-frequency power, for example, 13.56 MHz, to one end of the antenna 4 via the impedance adjustment unit 5. The control unit changes the capacitance of the variable capacitor in the impedance adjustment unit 7, thereby controlling the efficient supply of high-frequency power to the antenna 4 inside the processing chamber 2.

<Internal electrode 8>
Inside the processing chamber 2, an internal electrode 8 is provided on the opposite side of the antenna 4 from the substrate H1 to be processed (stage 3). The internal electrode 8 is attached to the inside of the processing chamber 2 via an insulating spacer 9 on the back side of the antenna 4. In other words, inside the processing chamber 2, the antenna 4 is disposed between the internal electrode 8 and the stage 3.

The internal electrode 8 is constructed using, for example, a carbon plate or a metal plate. The internal electrode 8 is a control electrode that controls the charged particles contained in the plasma inside the processing chamber 2. That is, the internal electrode 8 is connected to an electrode potential control unit 10 that includes a power supply (not shown) connected to the internal electrode 8 and controls the power supply so that a predetermined potential is applied to the internal electrode 8. The electrode potential control unit 10 variably adjusts the voltage applied to the internal electrode 8 from the electrode power supply in accordance with instructions from the control unit, thereby controlling the potential of the internal electrode 8 to a predetermined potential.

Furthermore, when the internal electrode 8 is constructed using a carbon plate, the carbon plate has a lower density than a metal plate, but is strong and is less likely to warp or otherwise occur in the internal electrode 8. Therefore, even when the internal electrode 8 is made larger, it is possible to reduce the likelihood of in-plane plasma non-uniformity due to warping or other factors.

Furthermore, it is preferable to use a metal material with low density and high electrical conductivity for the metal plate; specifically, it is preferable to use aluminum or an aluminum alloy. Furthermore, when the internal electrode 8 is constructed using a metal plate made of such a metal material, it is possible to construct an internal electrode 8 that is more resistant to mechanical shock than an internal electrode 8 made using a carbon plate, thereby improving the shock resistance of the plasma processing apparatus 1. As a result, for example, when vibrations caused by the opening and closing of a valve (not shown) are transmitted to the plasma processing apparatus 1, it is preferable to construct the internal electrode 8 using the above-mentioned metal plate.

As shown in Figure 2, the internal electrode 8 is composed of, for example, a punched metal grid electrode with multiple circular openings 8a. Depending on the polarity of the charged particles, the internal electrode 8 selectively imparts kinetic energy to the charged particles or reduces the amount of charged particles reaching the substrate H1 to be processed (details will be described later).

In addition to the above description, for example, a mesh-shaped grid electrode may be used as the internal electrode 8.

In addition to the above, a flat internal electrode 8 without an opening 8a can also be used.

<Example of operation>
The operation of the plasma processing apparatus 1 of the first embodiment will be specifically described with reference to Fig. 3. Fig. 3 is a diagram illustrating the function of the internal electrode 8. The following description will mainly focus on the operation of the internal electrode 8. In Fig. 3, the substrate H1 to be processed, the antenna 4, the power supply 6 connected thereto, and the like are not shown.

As shown in Figure 3, when the antenna 4 (Figure 1) operates to generate plasma inside the processing chamber 2, charged particles k contained in the plasma, unlike neutral particles n, move in response to the voltage applied to the internal electrode 8. That is, inside the processing chamber 2, as shown in Figure 3, the stage 3 is grounded, so charged particles k consisting of positive ions p and electrons or negative ions e move in response to the voltage applied to the internal electrode 8. That is, depending on their polarity, the charged particles k are selectively given kinetic energy by the internal electrode 8, or the amount of charged particles k that reach the processing target substrate H1 is reduced.

Specifically, as shown by arrow E in Figure 3, the electrode potential control unit 10 applies a positive voltage to the internal electrode 8 so that the potential of the internal electrode 8 is higher than the plasma potential. In this case, as shown in Figure 3, the kinetic energy of the positive ions p in the direction toward the substrate H1 to be processed is increased. As a result, the reaction of the positive ions p on the surface of the substrate H1 to be processed can be promoted, allowing a high-quality film to be formed on that surface.

On the other hand, as shown in Figure 3, the kinetic energy of the electrons or negative ions e is increased in the direction toward the internal electrode 8. This reduces the amount of electrons or negative ions e that reach the substrate H1 to be processed. As a result, in cases where the electrons or negative ions e degrade the quality of the coating formed on the surface of the substrate H1 to be processed by plasma processing, the degradation of the film quality can be suppressed.

The plasma processing apparatus 1 of this embodiment 1, configured as described above, includes a processing chamber 2. Inside the processing chamber 2, the plasma processing apparatus 1 of this embodiment 1 includes a stage 3 on which a substrate H1 (workpiece) to be processed is placed, and an antenna 4 for generating inductively coupled plasma inside the processing chamber 2. The plasma processing apparatus 1 of this embodiment 1 also includes an internal electrode 8 to which a predetermined potential is applied inside the processing chamber 2. As a result, unlike the conventional example described above, the plasma processing apparatus 1 of this embodiment 1 can appropriately control the behavior of charged particles k contained in the plasma inside the processing chamber 2 by applying a predetermined potential to the internal electrode 8.

In other words, in the plasma processing apparatus 1 of this embodiment 1, the antenna 4 is provided inside the processing chamber 2, allowing for efficient plasma generation. Furthermore, in the plasma processing apparatus 1 of this embodiment 1, the internal electrode 8 is provided inside the processing chamber 2, allowing for direct control of the movement and amount of plasma charged particles reaching the stage 3. Furthermore, in the plasma processing apparatus 1 of this embodiment 1, a predetermined potential can be applied to the internal electrode 8, thereby creating a large potential gradient between the internal electrode 8 and the substrate H1 to be processed.

As a result, in the plasma processing apparatus 1 of this embodiment 1, as illustrated in FIG. 3, kinetic energy can be selectively imparted to the charged particles k contained in the plasma depending on the polarity of the charged particles k. Therefore, in the plasma processing apparatus 1 of this embodiment 1, the amount of charged particles k reaching the substrate H1 to be processed can be increased or decreased. Therefore, in this embodiment 1, unlike the conventional example described above, the operation of the charged particles k can be appropriately controlled, making it possible to configure a plasma processing apparatus 1 that can perform high-quality plasma processing.

Furthermore, in the plasma processing apparatus 1 of this embodiment 1, the antenna 4 is a linear antenna and can be placed between the internal electrode 8 and the stage 3. As a result, in the plasma processing apparatus 1 of this embodiment 1, the positive ions p and electrons or negative ions e of the charged particles k of the plasma generated by the antenna 4 can be appropriately moved toward the substrate to be processed H1 or the internal electrode 8, respectively, depending on the processing content. As a result, in the plasma processing apparatus 1 of this embodiment 1, the amount of positive ions p, electrons, or negative ions e of the charged particles k that reach the substrate to be processed H1 can be easily increased or decreased. Therefore, the plasma processing apparatus 1 of this embodiment 1 can easily perform high-precision plasma processing on the substrate to be processed H1.

Furthermore, in the plasma processing apparatus 1 of this embodiment 1, an internal electrode 8 that acts as a shield is not installed between the antenna 4 and the substrate H1 to be processed on the stage 3. Therefore, in the plasma processing apparatus 1 of this embodiment 1, the amount of ions, radicals, etc. used in plasma processing that reach the substrate H1 to be processed can be increased. As a result, in the plasma processing apparatus 1 of this embodiment 1, the film formation rate or etching rate can be increased, making it easy to reduce costs while shortening takt time.

Furthermore, in the plasma processing apparatus 1 of this embodiment 1, the internal electrode 8 is disposed on the back side of the antenna 4 when viewed from the stage 3. As a result, in the plasma processing apparatus 1 of this embodiment 1, the electric field applied by the internal electrode 8 to the stage 3 can be applied not only between the antenna 4 and the stage 3, but also to a wide range of plasma, including plasma generated on the internal electrode 8 side of the antenna 4. Therefore, in the plasma processing apparatus 1 of this embodiment 1, the movement of charged particles in the plasma relative to the stage 3 can be efficiently controlled. As a result, the plasma processing apparatus 1 of this embodiment 1 can easily perform high-precision plasma processing on the substrate H1 to be processed.

Furthermore, in the plasma processing apparatus 1 of this embodiment 1, a linear antenna 4 is used as the antenna 4. By arranging multiple linear antennas 4 side by side, the plasma processing apparatus 1 of this embodiment 1 can arrange multiple antennas 4 inside the processing chamber 2 to accommodate a large substrate H1 to be processed.

Furthermore, in the plasma processing apparatus 1 of this embodiment 1, plasma processing is performed on the substrate H1 to be processed using a chemical vapor deposition method using plasma. As a result, the plasma processing apparatus 1 of this embodiment 1 can form a high-quality film on the substrate H1 to be processed.

[Embodiment 2]
Embodiment 2 of the present disclosure will be specifically described with reference to Fig. 4. Fig. 4 is a diagram illustrating the configuration of a plasma processing apparatus according to Embodiment 2 of the present disclosure. For ease of explanation, members having the same functions as those described in Embodiment 1 above will be denoted by the same reference numerals, and their description will not be repeated.

The main difference between this embodiment 2 and the above-described embodiment 1 is that multiple internal electrodes 8, the potential of which can be controlled independently of each other, are provided inside the processing chamber 2. Also, the potential of the stage 3 is variably controlled.

In the plasma processing apparatus 1 of this embodiment 2, as shown in FIG. 4, multiple, for example, two, internal electrodes 8 and 18 are provided inside the processing chamber 2. The internal electrode 18 is provided on the side of the substrate to be processed H1 (stage 3) relative to the antenna 4, so that the antenna 4 is positioned between the internal electrodes 8 and 18. The internal electrode 18 is also attached inside the processing chamber 2 via an insulating spacer 19. Like the internal electrode 8, the internal electrode 18 is configured, for example, in a punched metal shape, and is made of a carbon plate or metal plate with multiple openings, as shown in FIG. 2 (not shown).

The internal electrode 18 is connected to an electrode potential control unit 20, which includes an electrode power supply (not shown) connected to the internal electrode 18 and controls the electrode power supply to control the potential of the internal electrode 18. The electrode potential control unit 20 variably adjusts the voltage applied to the internal electrode 18 from the electrode power supply in accordance with instructions from the control unit, thereby controlling the potential of the internal electrode 18 to a predetermined potential. Furthermore, the electrode potential control unit 20 is configured to perform control independently of the electrode potential control unit 10, and the internal electrodes 8 and 18 can be controlled to have different potentials.

Furthermore, the plasma processing apparatus 1 of this embodiment 2 is capable of variably controlling the potential of the stage 3. Specifically, the stage 3 includes a power supply (not shown) connected to the stage 3, and is provided with a stage potential control unit 30 that controls the potential of the stage 3 by controlling the power supply.

The stage potential control unit 30 is configured to perform control independently of the electrode potential control units 10 and 20. The stage potential control unit 30 and the electrode potential control units 10 and 20 are configured to control the potentials of the stage 3, internal electrode 8, and internal electrode 18 to predetermined potentials, respectively, thereby enabling more appropriate control of the movement of the charged particles.

Specifically, if the potentials of the internal electrode 8, the internal electrode 18, and the stage 3 are set to a first potential, a second potential, and a third potential, respectively, in the plasma processing apparatus 1 of this embodiment 2, for example, the first potential > the second potential > the third potential. This allows the plasma processing apparatus 1 of this embodiment 2 to more effectively control the positive ions p and electrons or negative ions e shown in FIG. 3.

In other words, because the potential of stage 3 (third potential) is set to the lowest, the positive ions p are attracted to the potential of stage 3, increasing their kinetic energy in the direction toward the substrate H1 to be processed. As a result, the reaction of the positive ions p on the surface of the substrate H1 to be processed can be further promoted, allowing a higher quality film to be formed on that surface.

On the other hand, because the potential (first potential) of the internal electrode 8 is set to the highest, the electrons or negative ions e are attracted to the potential of the internal electrode 8, increasing their kinetic energy in the direction toward the internal electrode 8. This further reduces the amount of electrons or negative ions e that reach the substrate H1 to be processed. As a result, in cases where the electrons or negative ions e degrade the quality of the coating formed on the surface of the substrate H1 to be processed by plasma processing, the degradation of the film quality can be further suppressed.

With the above configuration, the plasma processing apparatus 1 of this second embodiment achieves the same effects as the first embodiment.

The plasma processing apparatus 1 of this embodiment 2 further includes a stage potential control unit 30 that controls the potential of the stage 3. As a result, in the plasma processing apparatus 1 of this embodiment 2, the stage potential control unit 30 controls the potential of the stage 3, thereby enabling more appropriate control of the behavior of the charged particles k.

In addition, in the plasma processing apparatus 1 of this embodiment 2, the internal electrode 18 is provided with an opening 18a, which allows the charged particles k generated inside the processing chamber 2, as well as the processing gas and film-forming precursor introduced into the processing chamber 2, to pass smoothly through the opening 18a. As a result, in the plasma processing apparatus 1 of this embodiment 1, even when the internal electrode 18 is provided between the antenna 4 and the stage 3, it is possible to suppress a decrease in the processing efficiency of plasma processing. Note that the film-forming precursor refers to the ions and radicals that result from ionization and/or excitation of the processing gas and molecules and/or atoms generated by decomposition of the processing gas that are introduced into the processing chamber 2.

Furthermore, in the plasma processing apparatus 1 of this embodiment 2, multiple internal electrodes 8 and 18 are provided inside the processing chamber 2. Furthermore, each of the multiple internal electrodes 8 and 18 is connected to an electrode potential control unit 10 and 20, respectively, which can control the potential of the internal electrodes 8 and 18 independently of each other. As a result, in the plasma processing apparatus 1 of this embodiment 2, the electrode potential control units 10 and 20 control the potential of the internal electrodes 8 and 18, respectively, thereby reliably controlling the appropriate behavior of the charged particles k. In other words, in the plasma processing apparatus 1 of this embodiment 2, the potential gradient inside the processing chamber 2 can be set more appropriately than in embodiment 1, allowing for more advanced control of the behavior of the charged particles k.

In addition to the above description, for example, the internal electrode 8 may be omitted. Alternatively, multiple internal electrodes whose potentials can be controlled independently may be provided between the antenna 4 and the stage 3.

〔summary〕
In order to solve the above problems, a plasma processing apparatus according to one aspect of the present disclosure is a plasma processing apparatus having a processing chamber, and is equipped with a stage inside the processing chamber on which an object to be processed is placed, an antenna for generating inductively coupled plasma inside the processing chamber, and an internal electrode to which a predetermined potential is applied.

With the above configuration, the plasma processing apparatus is equipped with an antenna inside the processing chamber for generating inductively coupled plasma, allowing for efficient plasma generation. Furthermore, the plasma processing apparatus is equipped with an internal electrode inside the processing chamber to which a predetermined potential is applied, allowing for direct control of the movement and amount of plasma charged particles relative to the stage, thereby providing a plasma processing apparatus capable of high-quality plasma processing.

In the plasma processing apparatus according to the above aspect, the antenna may be disposed between the internal electrode and the stage.

With the above configuration, the internal electrode is positioned on the back side of the antenna when viewed from the stage. This allows the electric field applied by the internal electrode to the stage to act on a wide range of plasma, including not only the plasma around the antenna, i.e., the area between the antenna and the stage, but also the plasma generated on the other side of the antenna when viewed from the stage. This allows for efficient control of the movement and amount of plasma charged particles relative to the stage. As a result, high-precision plasma processing of the workpiece can be easily performed.

In the plasma processing apparatus according to the above aspect, the antenna may be a linear antenna.

With the above configuration, the antenna can be placed inside the processing chamber to accommodate large objects to be processed.

The plasma processing apparatus according to the above aspect may further include a stage potential control unit that controls the potential of the stage.

The above configuration allows for more appropriate control of the charged particles.

In the plasma processing apparatus according to the above aspect, the internal electrodes may be provided in plurality, and the apparatus may further include a plurality of electrode potential control units connected to the plurality of internal electrodes, respectively, and the plurality of electrode potential control units may be capable of controlling the potentials of the plurality of internal electrodes independently of one another.

The above configuration enables more accurate and precise control of charged particles.

In the plasma processing apparatus according to the above aspect, the internal electrode may be made of a carbon plate or a metal plate having a plurality of openings.

With the above configuration, the opening allows charged particles generated inside the processing chamber and processing gas introduced into the processing chamber to pass smoothly through, and even when the internal electrode is installed between the antenna and the stage, a decrease in processing efficiency during plasma processing can be suppressed.

In the plasma processing apparatus according to the above aspect, a film may be formed on the workpiece placed on the stage by chemical vapor deposition using the plasma.

The above configuration allows high-quality film formation to be performed on the workpiece.

This disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

REFERENCE SIGNS LIST 1 Plasma processing apparatus 2 Processing chamber 3 Stage 4 Antenna 8 Internal electrode 8a Opening 10, 20 Electrode potential control unit 30 Stage potential control unit H1 Substrate to be processed (object to be processed)
k charged particle p positive ion e electron or negative ion

Claims (6)

A plasma processing apparatus including a processing chamber,
Inside the processing chamber,
a stage on which the object to be processed is placed;
an antenna for generating an inductively coupled plasma within the processing chamber;
an internal electrode to which a predetermined potential is applied ;
the internal electrode is attached to the inside of the processing chamber via an insulating spacer provided on the opposite side of the internal electrode from the side on which the antenna is provided,
The plasma processing apparatus, wherein the antenna is disposed between the internal electrode and the stage. The plasma processing apparatus according to claim 1 , wherein the antenna is a linear antenna. 3. The plasma processing apparatus according to claim 1 , further comprising a stage potential control unit that controls a potential of the stage. A plurality of the internal electrodes are provided,
further comprising a plurality of electrode potential control units connected to the plurality of internal electrodes, respectively;
The plasma processing apparatus according to claim 1 , wherein the plurality of electrode potential control units are capable of controlling the potentials of the plurality of internal electrodes independently of one another. 5. The plasma processing apparatus according to claim 1, wherein the internal electrode is made of a carbon plate or a metal plate having a plurality of openings. The plasma processing apparatus according to claim 1 , wherein a film is formed on the object to be processed placed on the stage by a chemical vapor deposition method using the plasma.