JP7574451B2 - Vacuum Processing Equipment - Google Patents

Description

The present invention relates to a vacuum processing apparatus, and more specifically, to an apparatus for performing a predetermined process on a substrate to be processed in a vacuum atmosphere.

This type of vacuum processing apparatus is used to perform various vacuum processes, such as film formation by sputtering, vacuum deposition or CVD, dry etching, ion implantation, and heat treatment, on a substrate to be processed in a vacuum atmosphere. For example, a sputtering apparatus that performs film formation by sputtering on a large-area glass substrate in the manufacturing process of a flat display panel includes a vacuum chamber, to which a vacuum pump for evacuating the inside of the vacuum chamber is connected, and a stage on which the substrate to be processed is set is provided in the vacuum chamber. A rotation axis is provided on the stage, and the stage is configured to be freely oscillated around the rotation axis between a horizontal position (first position) in which the main surface of the stage on which the substrate to be processed is set faces vertically upward, and an upright position (second position) in which the main surface of the stage on which the substrate to be processed is set faces horizontally. A sputtering cathode unit is disposed as a processing unit on the wall of the vacuum chamber, facing the main surface of the upright stage (see, for example, Patent Document 1).

Meanwhile, the above-mentioned various vacuum processing devices are periodically maintained by operators manually, such as replenishing the deposition material, replacing the target material, and replacing the adhesion prevention plate that prevents the deposition material from adhering to the inner wall surface of the vacuum chamber. Even if the vacuum chamber is installed in a clean room with a certain level of air cleanliness, particles floating in the clean room may be brought into the vacuum chamber and adhere to the main surface of the stage, etc. Since such particles may hinder good vacuum processing, it is desirable to remove the particles that have been brought in after maintenance is completed (for example, with the recent trend toward higher resolution and higher functionality, vacuum processing devices used in the manufacturing process of flat display panels are required to reduce the number of particles below a certain size as much as possible).

As one method for removing particles, a so-called cycle vent is generally known, in which the vacuum chamber is alternately switched between an air atmosphere and a vacuum atmosphere of a predetermined pressure several times. According to this, when a vent gas such as nitrogen gas or argon gas is introduced into the vacuum chamber, particles attached to the main surface of the stage are stirred up, and when the vacuum chamber is then evacuated by the vacuum pump, the stirred up particles are transferred to the vacuum pump, so that the particles can be removed as much as possible. Such cycle vent is effective, for example, in vacuum processing equipment used in the manufacturing process of semiconductor devices, where the size of the substrate (silicon wafer) to be processed is relatively small and the volume of the vacuum chamber does not need to be large. However, in vacuum processing equipment used in the manufacturing process of flat display panels, where the size of the substrate to be processed is relatively large and the volume of the vacuum chamber must be large, the particles cannot be effectively removed. Furthermore, if the volume of the vacuum chamber is large, it takes a lot of time to vent the vacuum chamber and to exhaust the vacuum chamber to return it to the air, thereby reducing productivity.

International Publication WO2019/082868

In view of the above, the present invention has as its objective the provision of a vacuum processing apparatus capable of eliminating as many particles as possible while maintaining a vacuum atmosphere.

In order to solve the above problems, the vacuum processing apparatus of the present invention has a vacuum chamber in which a processing unit that performs a predetermined processing on a substrate to be processed in a vacuum atmosphere is installed, a vacuum pump that evacuates the inside of the vacuum chamber is connected to the vacuum chamber, and a stage on which the substrate to be processed is set is provided in the vacuum chamber, the attitude of the stage in which the substrate to be processed set on the stage faces the processing unit and the predetermined processing is performed is defined as a first attitude, and the attitude of the stage other than when the predetermined processing is performed is defined as a second attitude, and the apparatus is provided with a swinging means for swinging the stage around a rotation axis between the first attitude and the second attitude, and further includes a spraying means for spraying an inert gas toward the stage in the vacuum chamber, and the spraying means is configured to be capable of switching the flow rate between a first flow rate that enables the blowing off of particles attached to at least one of the stage and the substrate to be processed when the vacuum chamber is in a vacuum atmosphere of a predetermined pressure, and a second flow rate that enables the transfer of particles that have been diffused in the vacuum chamber by the blowing off to the vacuum pump.

According to the present invention, after an operator performs maintenance such as replenishing the deposition material, replacing the target material, and replacing the adhesion prevention plate that prevents the deposition material from adhering to the inner wall surface of the vacuum chamber, the vacuum chamber is evacuated to a predetermined pressure range of the viscous flow region (for example, a range of 5 Pa to 1000 Pa) by the vacuum pump. When the predetermined pressure range is reached, an inert gas such as nitrogen gas or argon gas is sprayed to the stage at a first flow rate by the spraying means with the stage in the second position. The first flow rate is set to, for example, a range of 1 SLM to 100 SLM, preferably 10 SLM or more, and at this time, the effective exhaust speed of the vacuum pump is appropriately set so that the inside of the vacuum chamber is maintained within the above pressure range. The spraying time of the inert gas at the first flow rate can be determined, for example, experimentally in advance or calculated by simulation. The inert gas at the first flow rate can be sprayed onto the stage after the vacuum chamber has been evacuated to a high vacuum (e.g., 10 ⁻⁵ Pa) by a vacuum pump, or can be sprayed while the substrate to be processed is set on the stage in order to subject the substrate to vacuum processing. This causes particles adhering to the stage and substrate to be blown away and stirred up, resulting in a state in which they are dispersed within the vacuum chamber (particle stirring process).

Next, when the particles adhering to the stage or the substrate to be processed have finished being stirred up, the spraying means switches from the first flow rate to the second flow rate to introduce the inert gas into the vacuum chamber. The second flow rate is set, for example, to a flow rate in the range of 300 sccm to 1000 sccm depending on the size of the stirred up particles, and at this time, as above, the effective exhaust speed of the vacuum pump is appropriately set so that the inside of the vacuum chamber is maintained within the above pressure range. As a result, the particles that have diffused in the vacuum chamber are guided to the exhaust port of the vacuum chamber that communicates with the vacuum pump, and are transferred to the vacuum pump (particle transfer process). The spraying time at the second flow rate of the inert gas can be determined, for example, experimentally in advance or calculated by simulation, as above. The stirring process and the transfer process may be repeated multiple times in sequence.

In this way, in the present invention, a relatively large amount (first flow rate) of inert gas is sprayed into the vacuum chamber to raise the particles adhering to the stage, etc., and a relatively small amount (second flow rate) of inert gas is introduced and guided to the exhaust port so that the raised particles do not further adhere to the stage, etc., thereby removing as many particles as possible while maintaining the vacuum atmosphere in the vacuum chamber. Moreover, since there is no need to repeat venting and exhausting processes to return the inside of the vacuum chamber to the atmospheric atmosphere, the time required to remove the particles is short, which is advantageous when the volume of the vacuum chamber is large. Moreover, since inert gas is used, the substrate to be processed is set on the stage in the second position, and in this state the stage is swung to the first position to perform vacuum processing, and the particles can be removed prior to the vacuum processing.

In the present invention, the spraying means may be configured to include a spray nozzle disposed parallel to the axis of rotation above the stage in the vacuum chamber and having a length equal to or greater than the width of the stage along the axis of rotation, and to spray a line of inert gas at a first flow rate from the spray nozzle while the stage is oscillated between a first position and a second position. In this way, the swinging of the stage can be used to spray the inert gas over the entire main surface of the stage on which the substrate to be processed is set, and particles adhering to the stage can be reliably lifted up.

In the present invention, the spraying means may be provided with a spray nozzle arranged parallel to the rotation axis above the stage in the vacuum chamber and having a length equal to or greater than the width of the stage along the rotation axis, and may have a drive source for swinging the nozzle hole of the spray nozzle around another rotation axis parallel to the rotation axis. This allows the inert gas to be sprayed over the entire main surface of the stage on which the substrate to be processed is set, for example, even when the stage is not swung, and is advantageous in that the nozzle hole of the spray nozzle can be swung when the inert gas is blown out at the second flow rate, thereby more reliably directing the particles that have been stirred up to the exhaust port. If the exhaust port of the vacuum chamber to which the exhaust pipe from the vacuum pump is connected is opened below the stage, the gravity can also be added to more reliably guide the particles that have been stirred up to the exhaust port.

FIG. 1 is a schematic cross-sectional view of a vacuum processing apparatus (sputtering apparatus) according to an embodiment of the present invention. FIG.

Below, with reference to the drawings, an embodiment of the vacuum processing apparatus of the present invention will be described using an example in which the processing in a vacuum atmosphere is a film formation process using a sputtering method, the processing unit is a sputtering cathode, the substrate to be processed is a glass substrate (hereinafter referred to as "substrate Sw"), and a predetermined thin film is formed on one surface of the substrate Sw in a vacuum chamber in a vacuum atmosphere. In the following, terms indicating directions such as up and down are based on Figure 1, which shows the installation posture of the vacuum processing apparatus.

Referring to FIG. 1, the vacuum processing apparatus (sputtering apparatus) VM includes a main chamber 1 having a substantially box-like shape. The upper wall of the main chamber 1 located vertically upward has a curved shape corresponding to the swing of the stage, in order to minimize the volume of the main chamber 1 while allowing the swing of the stage described below. An auxiliary chamber 2 is connected to one side wall of the main chamber 1 (left side wall in FIG. 1), and the auxiliary chamber 2 and the main chamber 1 can communicate with each other through an opening 11 provided in one side wall of the main chamber 1. An opening 13 for substrate transport, which can be opened and closed by a shutter plate 12, is provided in the other side wall of the main chamber 1 (right side wall in FIG. 1), and the substrate Sw can be freely inserted and removed from the main chamber 1 through the opening 13. An exhaust port 14 is formed in the bottom wall of the main chamber 1 located vertically downward, and an exhaust pipe 15a from a vacuum pump 15 is connected to the exhaust port 14, so that the main chamber 1 can be evacuated from atmospheric pressure to a high vacuum region. In this embodiment, an exhaust port 14 is provided below a spray nozzle, which will be described later, and a conductance valve 15b is provided in an exhaust pipe 15a so that the effective exhaust speed of the vacuum pump 15 can be adjusted.

A stage 3 that can swing freely while holding a substrate Sw is provided in the main chamber 1. The stage 3 has a support plate portion 31 that has an area slightly larger than the substrate Sw and has functional parts that hold the substrate Sw. Although not specifically shown or described, known parts such as claws and mechanical clamps provided on the outer periphery of the upper surface of the support plate portion 31 can be used as the functional parts. An arm portion 32 that extends diagonally downward is attached to one end of the lower surface of the support plate portion 31 located on the auxiliary chamber 2 side, and the lower end of the arm portion 32 is connected to a rotating shaft portion 33 that is journaled in the main chamber 1 so as to extend horizontally. One end of the rotating shaft portion 33 (in the depth direction in FIG. 1) is connected to the output shaft of a motor 34 as a driving means. This allows the stage 3 to freely swing between a first position in which the main surface (the surface on which the substrate Sw is held) of the support plate portion 31 of the stage 3 that holds the substrate Sw faces vertically upward, and a second position in which the outer peripheral edge of the support plate portion 31 abuts against the inner surface of one side wall portion of the main chamber 1 that is located at the outer peripheral edge of the opening 11.

A sputtering cathode 4 is provided in the auxiliary chamber 2 as a processing unit. The sputtering cathode 4 has a target 41 arranged directly opposite the stage 3 in the second position, and is installed in the auxiliary chamber 2 via a backing plate 42 bonded to one surface of the target 41. Although not specifically shown or described, a vacuum pump is also connected to the auxiliary chamber 2, and a rare gas such as argon gas introduced when forming plasma in the vacuum chamber 1 and a reactive gas during reactive sputtering can be introduced. Then, a predetermined power or AC power having a negative potential according to the target species is input to the target 41 from a sputtering power source not shown in the figure, and a plasma is formed in the auxiliary chamber 2 to sputter the target 41, thereby forming a predetermined thin film on the surface of the substrate Sw.

Meanwhile, maintenance such as replacing the target 41 and the adhesion prevention plate (not shown) is periodically performed manually by an operator on the vacuum processing apparatus VM. At this time, even if the main chamber 1 is installed in a clean room with a predetermined air cleanliness, particles floating in the clean room may be brought into the main chamber 1 and adhere to the support plate portion 31 of the stage 3. Since such particles have a negative effect on the film formation on the substrate Sw, it is necessary to reduce the number of particles below a predetermined size as much as possible prior to the film formation process. In this embodiment, a spraying means 5 is provided to spray an inert gas toward the stage 3.

Referring also to FIG. 2, the spraying means 5 includes a spray nozzle 51 provided on the inner surface of the upper wall of the main chamber 1. The spray nozzle 51 is composed of a metal cylinder longer than the width (width in the depth direction in FIG. 1) of the support plate portion 31 of the stage 3, and a plurality of nozzle holes 51a are arranged at intervals in one direction on its outer circumferential surface, and the inert gas can be blown out in a line from each nozzle hole 51a. In addition, a gas pipe 52 that penetrates the upper wall of the main chamber 1 and protrudes into the inside is connected to the spray nozzle 51. In this case, although not particularly shown or described, a diffusion plate may be arranged in the spray nozzle 51 to diffuse the inert gas supplied through the gas pipe 52 so that the inert gas is blown out approximately evenly from each nozzle hole 51a. The gas pipe 52 is connected to a gas source not shown via a flow control valve 53. As the inert gas, a rare gas such as nitrogen gas or argon gas is used, and the flow control valve 53 switches between a first flow rate that allows the particles adhering to the stage 3 and the substrate Sw to be blown off, and a second flow rate that allows the particles that are stirred up to be diffused in the main chamber 1 and sent to the exhaust port 14, so that the inert gas can be supplied to the spray nozzle 51. The spray nozzle 51 is also connected to a rotating shaft of a motor 54 as a drive source that rotates the spray nozzle 51 around its axis (rotation axis), and by rotating the spray nozzle 51 back and forth within a predetermined angular range, each nozzle hole 51a can be swung back and forth around the axis within a predetermined angular range. The procedure for removing particles after maintenance is described below.

After the maintenance, the vacuum pump 15 evacuates the main chamber 1 and the auxiliary chamber 2 to a predetermined pressure range (for example, 5 Pa to 1000 Pa) in the viscous flow region with the stage 3 in the second position. When the predetermined pressure range is reached, the flow control valve 53 is controlled to supply the inert gas to the spray nozzle 51 at a first flow rate, and the inert gas is sprayed in a line shape from each nozzle hole 51a at the first flow rate. The first flow rate is set, for example, to a range of 1 SLM to 100 SLM, preferably 10 SLM or more, and the opening of the conductance valve 15b is appropriately adjusted so that the pressure inside the main chamber 1 is maintained within the above pressure range. In addition, the motor 54 rotates the spray nozzle 51 back and forth within a predetermined angle range, and the stage 3 is oscillated until the first position is reached. The spray time of the inert gas at the first flow rate can be determined, for example, experimentally or calculated in advance by simulation, and the oscillation speed of the stage 3 is set accordingly. The inert gas at the first flow rate can be sprayed onto the stage 3 after the main chamber 1 and the auxiliary chamber 2 have been evacuated to a high vacuum (e.g., 10 ⁻⁵ Pa) by the vacuum pump 15, and can also be sprayed with the substrate Sw set on the stage 3 for film formation on the substrate Sw. As a result, a line of inert gas is sprayed onto the stage 3 including the entire main surface of the support plate portion 31, and particles adhering to the stage 3 and the substrate Sw are blown away and lifted up, and are dispersed within the main chamber 1 (particle lifting process).

Next, when the stage 3 is in the first position and the particles adhering to the stage 3 and the substrate Sw are lifted up, the stage 3 maintains the first position (i.e., the main chamber 1 and the auxiliary chamber 2 are kept isolated from each other) and the flow control valve 53 is controlled to supply the inert gas to the spray nozzle 51 at the second flow rate while maintaining the rotation of the spray nozzle 51, and the inert gas is blown out in a line shape from each nozzle hole 51a at the second flow rate. The second flow rate is set to a flow rate in the range of, for example, 300 sccm to 1000 sccm depending on the size of the lifted particles, and at this time, the opening of the conductance valve 15b is appropriately adjusted so that the pressure inside the main chamber 1 is maintained within the above pressure range, as described above. As a result, the particles dispersed in the main chamber 1 are guided by gravity to the exhaust port 14 and transferred to the vacuum pump 15 (particle transfer process). The spraying time of the inert gas at the second flow rate can be experimentally obtained in advance or calculated by simulation, as described above. In addition, such a flying step and a transporting step can be repeated multiple times, and in the flying step of the particles, the inert gas can be sprayed at the first flow rate when the stage 3 is swung from the first attitude to the second attitude.

According to the above embodiment, a relatively large amount (first flow rate) of inert gas is sprayed to raise the particles attached to the stage 3, etc., and a relatively small amount (second flow rate) of inert gas is introduced and guided to the exhaust port 14 so that the raised particles do not further adhere to the stage 3, etc., thereby making it possible to discharge the particles brought in as much as possible while maintaining the vacuum atmosphere in the main chamber 1. Moreover, since there is no need to repeat the venting process and exhaust process to return the inside of the main chamber 1 to the atmospheric atmosphere, the time required to remove the particles is short, which is advantageous when the volume of the main chamber 1 is large. Furthermore, in order to use inert gas, the substrate Sw is set on the stage 3 in the second position, and in this state the stage 3 is swung to the first position, and the particles can be removed prior to film formation.

Although the embodiment of the present invention has been described above, various modifications are possible without departing from the scope of the technical concept of the present invention. In the above embodiment, the spraying means 5 has been described as having a spray nozzle 51 on the inside of the upper wall of the main chamber 1, but the form and arrangement are not limited to this as long as the first flow rate of inert gas can be sprayed over the entire main surface of the support plate portion 31, which is most likely to have an effect during vacuum processing. For example, if the stage 3 is oscillated as in this embodiment, the spray nozzle 51 does not need to be rotated. In addition, in the above embodiment, the exhaust port 14 is provided on the bottom wall of the main chamber 1, but the position is not limited to this as long as the particles diffused in the main chamber 1 are guided to the position. Furthermore, in the above embodiment, a sputtering device is used as an example, but the present invention can be applied to other vacuum processing devices such as film formation processing devices using a vacuum deposition method or a CVD method, dry etching processing devices, and ion implantation processing devices, as long as they use an oscillating stage.

VM...vacuum processing apparatus, Sw...substrate (substrate to be processed), 1...main chamber (vacuum chamber), 2...auxiliary chamber (vacuum chamber), 3...stage, 4...sputtering cathode (processing unit), 5...spraying means, 51...spraying nozzle, 14...exhaust port, 15...vacuum pump, 15a...exhaust pipe, 54...motor (driving source).

Claims (3)

a vacuum processing apparatus having a vacuum chamber in which a processing unit is installed which performs a predetermined processing on a substrate to be processed in a vacuum atmosphere, a vacuum pump which evacuates the inside of the vacuum chamber is connected to the vacuum chamber, and a stage on which the substrate to be processed is set is provided in the vacuum chamber, a first position is a position of the stage in which the substrate to be processed set on the stage faces the processing unit and the predetermined processing is performed, and a second position is a position of the stage other than when the predetermined processing is performed, and the apparatus is provided with a swinging means which swings the stage around a rotation axis between the first position and the second position;
the apparatus further includes a spraying means for spraying an inert gas toward the stage into the vacuum chamber, the spraying means being configured to be able to switch a flow rate between a first flow rate that makes it possible to blow off particles adhering to at least one of the stage and the substrate to be processed while maintaining a vacuum atmosphere of a predetermined pressure inside the vacuum chamber, and a second flow rate that makes it possible to transfer particles that have been blown off and diffused into the vacuum chamber to the vacuum pump ;
The vacuum processing apparatus is characterized in that the spraying means includes a spray nozzle arranged above the stage within the vacuum chamber parallel to the rotation axis and having a length equal to or greater than the width of the stage along the rotation axis, and a first flow rate of inert gas is sprayed in a line from the spray nozzle while the stage is oscillated between a first position and a second position . a vacuum processing apparatus having a vacuum chamber in which a processing unit is installed which performs a predetermined processing on a substrate to be processed in a vacuum atmosphere, a vacuum pump which evacuates the inside of the vacuum chamber is connected to the vacuum chamber, and a stage on which the substrate to be processed is set is provided in the vacuum chamber, a first position is a position of the stage in which the substrate to be processed set on the stage faces the processing unit and the predetermined processing is performed, and a second position is a position of the stage other than when the predetermined processing is performed, and the apparatus is provided with a swinging means which swings the stage around a rotation axis between the first position and the second position;
the apparatus further includes a spraying means for spraying an inert gas toward the stage into the vacuum chamber, the spraying means being configured to be able to switch a flow rate between a first flow rate that makes it possible to blow off particles adhering to at least one of the stage and the substrate to be processed while maintaining a vacuum atmosphere of a predetermined pressure inside the vacuum chamber, and a second flow rate that makes it possible to transfer particles that have been blown off and diffused into the vacuum chamber to the vacuum pump;
The vacuum processing apparatus is characterized in that the spraying means includes a spray nozzle arranged parallel to the rotation axis above the stage within the vacuum chamber and having a length equal to or greater than the width of the stage along the rotation axis, and has a drive source that oscillates the nozzle hole of the spray nozzle around another rotation axis parallel to the rotation axis. 3. The vacuum processing apparatus according to claim 1, wherein an exhaust port of said vacuum chamber to which an exhaust pipe from said vacuum pump is connected is opened and positioned below said stage.

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