JP2022147006A - Plasma processing apparatus, and plasma processing method - Google Patents

Abstract

To provide a plasma processing apparatus and a plasma processing method, enabling suppression of contamination of processed substances due to contaminants.SOLUTION: A plasma processing apparatus 1 comprises: a first chamber 51 which maintains atmosphere depressurized to pressure lower than atmospheric pressure, and can mount a processing-object substance inside the first chamber 51; a first exhaust section which can depressurize the inside of the first chamber to predetermined pressure; a plasma generation section which can generate plasma; a first gas supply section which can supply processing gas; a second chamber 71 which is connected to the first chamber, and can maintain the atmosphere depressurized to pressure lower than the atmospheric pressure; a conveyance section 4 which can convey the processing-object substance in a space from the first chamber; a second exhaust section 73 which can depressurize the inside of the second chamber to a predetermined pressure; a second gas supply section 74 which can supply gas into the inside of the second chamber. When conveying the processing-object substance by the conveyance section, the pressure inside the second chamber is adjusted to the pressure nearly equal to the pressure inside the first chamber. When the conveyance of the processing-object substance by the conveyance section is terminated, the gas is supplied into the inside of the second chamber.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD Embodiments of the present invention relate to a plasma processing apparatus and a plasma processing method.

A dry process using plasma is utilized, for example, in manufacturing a fine structure. For example, in the manufacture of semiconductor devices, flat panel displays, photomasks, etc., various plasma treatments such as etching, ashing, and damage removal are performed.

Plasma processing apparatuses for performing such plasma processing include, for example, a process chamber for performing plasma processing on an object to be processed, a transfer chamber connected to the process chamber via a gate valve, and a transfer chamber provided inside the process chamber. A transport robot or the like for transporting the processed material is provided between them.

Here, contaminants containing organic matter may be generated inside the transfer chamber. Since the material to be processed is transferred inside the transfer chamber, if contaminants are generated, the generated contaminants may adhere to the surface of the material to be processed. In this case, when a workpiece with contaminants adhered thereto is carried into the process chamber and plasma-processed, the quality of the product may be affected. In addition, when the object to be processed with contaminants adhered thereto is carried out from the transfer chamber, there is a possibility that the processing in the subsequent process will be affected.
Therefore, techniques for suppressing contamination of the processed material with contaminants have been proposed (see Patent Documents 1 and 2, for example).

However, in recent years, the materials of microstructures have been diversified and miniaturized, and there is a risk that contaminants will have a greater impact on quality.
Therefore, it has been desired to develop a technique capable of further suppressing contamination by contaminants.

JP-A-6-196540 JP-A-2003-17478

A problem to be solved by the present invention is to provide a plasma processing apparatus and a plasma processing method capable of suppressing contamination by contaminants.

A plasma processing apparatus according to an embodiment includes a first chamber capable of maintaining an atmosphere reduced to a pressure lower than atmospheric pressure, in which an object to be processed can be placed, and capable of reducing the pressure inside the first chamber to a predetermined pressure. a first exhaust section, a plasma generation section capable of generating the plasma, and a first gas supply section capable of supplying a process gas to a region in the first chamber where the plasma is generated. a second chamber connected to the first chamber via a gate valve and capable of maintaining an atmosphere reduced below atmospheric pressure; provided inside the second chamber; a transfer section capable of transferring the object to be processed to and from the chamber; a second exhaust section capable of decompressing the inside of the second chamber to a predetermined pressure; and a controller capable of controlling the transfer section, the second exhaust section, and the second gas supply section. The controller controls the second exhaust unit when the transport unit transports the object to be processed so that the pressure inside the second chamber is reduced to the pressure inside the first chamber. and the second gas supply unit is controlled to supply the gas to the inside of the second chamber when the transfer of the object to be processed by the transfer unit is completed.

According to embodiments of the present invention, a plasma processing apparatus and a plasma processing method capable of suppressing contamination by contaminants are provided.

1 is a layout diagram for illustrating a plasma processing apparatus according to an embodiment; FIG. It is a schematic cross section for illustrating an example of a processing unit. FIG. 10 is a schematic cross-sectional view for illustrating a processing section according to another embodiment; FIG. 3 is a schematic cross-sectional view for illustrating a transfer section; Fig. ₃ is a vapor pressure _curve of _C16H30O4 ; 4 is a timing chart for illustrating gas supply;

Hereinafter, embodiments of the present invention will be illustrated with reference to the drawings. In addition, in each drawing, the same reference numerals are given to the same constituent elements, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a layout diagram illustrating a plasma processing apparatus 1 according to this embodiment.
As shown in FIG. 1, the plasma processing apparatus 1 has, for example, a controller 2, a storage section 3, a transfer section 4, a load lock section 5, a processing section 6, and a transfer section .

The controller 2 has, for example, an arithmetic unit such as a CPU (Central Processing Unit) and a storage unit such as a memory. The controller 2 is, for example, a computer or the like. The controller 2 controls the operation of each element provided in the plasma processing apparatus 1 based on, for example, a control program stored in the storage unit.

The storage unit 3 stores, for example, the objects 100 to be processed in a layered (multistage) manner. The storage unit 3 is, for example, a so-called pod or a FOUP (Front-Opening Unified Pod) that is a front-opening carrier. However, the storage unit 3 is not limited to the illustrated one, and may be any storage unit that can store the object 100 to be processed. At least one storage unit 3 can be provided.

The transport section 4 is provided between the storage section 3 and the load lock section 5 . The transport unit 4 transports and delivers the workpiece 100 between the storage unit 3 and the load lock unit 5 . In this case, the transport unit 4 transports and delivers the workpiece 100 in an environment with a higher pressure (for example, atmospheric pressure) than the pressure at the time of plasma processing. The transport unit 4 is, for example, a transport robot having an arm that holds the workpiece 100 .

The load lock section 5 is provided between the transport section 4 and the transfer section 7 . The load lock unit 5 transfers the workpiece 100 between the transfer unit 4 and the transfer unit 7, which have different atmospheric pressures. Therefore, the load lock section 5 has a chamber 51 , an exhaust section 52 and a gas supply section 53 .

The chamber 51 has an airtight structure capable of maintaining an atmosphere pressure-reduced below atmospheric pressure. A side wall of the chamber 51 is provided with an opening for loading and unloading the object 100 to be processed. A gate valve 51a for opening and closing the opening is also provided. The chamber 51 is connected to a chamber 71 (corresponding to an example of a second chamber) of the transfer section 7 via a gate valve 51a.

The exhaust part 52 exhausts the inside of the chamber 51 so that the pressure inside the chamber 51 becomes substantially equal to the pressure inside the chamber 71 of the delivery part 7 . The exhaust unit 52 can have, for example, a turbomolecular pump (TMP) and a pressure control unit (APC: Auto Pressure Controller).

The gas supply unit 53 supplies gas to the inside of the chamber 51 so that the pressure inside the chamber 51 is substantially equal to the pressure of the transfer unit 4 . The supplied gas can be, for example, air or nitrogen gas.

The processing unit 6 plasma-processes the workpiece 100 in an atmosphere whose pressure is reduced below atmospheric pressure.
The processing section 6 can be, for example, a plasma processing device such as a plasma etching device, a plasma ashing device, a sputtering device, or a plasma CVD device.
In this case, the plasma generation method is not particularly limited, and for example, plasma can be generated using high frequency waves, microwaves, or the like.
However, the type of plasma processing apparatus and plasma generation method are not limited to those illustrated. In other words, the processing unit 6 may perform plasma processing on the processing object 100 in an atmosphere that is reduced in pressure below the atmospheric pressure.

Also, the number of processing units 6 is not particularly limited. At least one processing unit 6 may be provided. When a plurality of processing units 6 are provided, the same type of plasma processing apparatuses can be provided, or different types of plasma processing apparatuses can be provided. Further, when a plurality of plasma processing apparatuses of the same type are provided, the processing conditions can be different for each, or the processing conditions can be the same for each.

FIG. 2 is a schematic cross-sectional view for illustrating an example of the processing section 6. As shown in FIG.
The processing section 6 illustrated in FIG. 2 is an inductively coupled plasma processing apparatus. That is, it is an example of a plasma processing apparatus that processes an object 100 by generating plasma products from a process gas G using plasma P excited and generated by high-frequency energy.

As shown in FIG. 2, the processing section 6 includes, for example, a chamber 61 (corresponding to an example of a first chamber), a mounting section 62, an antenna 63, high frequency power supplies 64a and 64b, a gas supply section 65 (first (corresponding to an example of a gas supply section), an exhaust section 66 (corresponding to an example of a first exhaust section), and the like.

The chamber 61 has, for example, a substantially cylindrical shape with a bottom, and has an airtight structure capable of maintaining an atmosphere pressure-reduced below atmospheric pressure. A transmission window 61a is provided in the upper part of the chamber 61 so as to be airtight. The transmissive window 61a has a plate-like shape and can be made of a material that has a high transmittance to high-frequency energy and is difficult to etch during plasma processing. The transmissive window 61a can be made of a dielectric material such as quartz, for example.

A side wall of the chamber 61 is provided with an opening 61b for loading and unloading the object 100 to be processed. A gate valve 61c is provided to open and close the opening 61b. The chamber 61 is connected to the chamber 71 of the transfer section 7 via a gate valve 61c.

The mounting section 62 is provided inside the chamber 61 . A workpiece 100 is placed on the upper surface of the placing portion 62 . In this case, the workpiece 100 may be placed directly on the upper surface of the placement section 62, or may be placed on the placement section 62 via a support member (not shown) or the like. Further, a holding device such as an electrostatic chuck can be provided on the mounting portion 62 .

The antenna 63 supplies high-frequency energy (electromagnetic energy) to a region inside the chamber 61 where the plasma P is generated. Plasma P is generated by the high-frequency energy supplied to the interior of the chamber 61 . For example, the antenna 63 supplies high frequency energy to the interior of the chamber 61 through the transmissive window 61a.

The high frequency power supply 64a is electrically connected to the antenna 63 via a matching box 64a1. The matching box 64a1 is provided with a matching circuit or the like for matching the impedance on the high frequency power supply 64a side and the impedance on the plasma P side. The high frequency power supply 64a is a power supply for generating the plasma P. That is, the high-frequency power supply 64a is provided to generate the plasma P by generating high-frequency discharge inside the chamber 61 . The high-frequency power supply 64a applies high-frequency power having a frequency of about 100 KHz to 100 MHz to the antenna 63. FIG.
In this embodiment, the antenna 63 and the high-frequency power source 64a serve as a plasma generator for generating the plasma P. FIG.

The high frequency power supply 64b is electrically connected to the mounting section 62 via a matching device 64b1. The matching circuit 64b1 is provided with a matching circuit or the like for matching the impedance on the high frequency power supply 64b side and the impedance on the plasma P side. The high-frequency power supply 64b controls the energy of ions that are drawn into the workpiece 100 placed on the placement section 62 . The high-frequency power supply 64b applies high-frequency power having a relatively low frequency (for example, 13.56 MHz or less) suitable for attracting ions to the mounting section 62 .

The gas supply unit 65 supplies the process gas G to the region where the plasma P is generated inside the chamber 61 via the flow control unit 65a. The flow controller 65a can be, for example, a mass flow controller (MFC: Mass Flow Controller). The gas supply part 65 can be connected, for example, to the side wall of the chamber 61 near the transmission window 61a.

The process gas G is appropriately selected according to the type of processing, the material of the processing surface of the processing object 100, and the like. For example, in the case of etching, a process gas G containing fluorine atoms such as CF ₄ and CF ₃ can be used so as to generate highly reactive radicals. In this case, the process gas G can be, for example, only a gas containing fluorine atoms, or a mixed gas of a gas containing fluorine atoms and a rare gas.

The exhaust unit 66 reduces the pressure inside the chamber 61 to a predetermined pressure. Exhaust 66 may be, for example, a turbomolecular pump (TMP). The exhaust section 66 can be connected to the bottom surface of the chamber 61 via the pressure control section 66a. Based on the output of a pressure gauge (not shown) that detects the pressure inside the chamber 61, the pressure control unit 66a controls the inside of the chamber 61 to a predetermined pressure. The pressure control unit 66a can be, for example, an auto pressure controller (APC: Auto Pressure Controller).

When subjecting the workpiece 100 to plasma processing, the inside of the chamber 61 is depressurized to a predetermined pressure by the exhaust unit 66, and a predetermined amount of process gas G (for example, CF ₄ or the like) is supplied from the gas supply unit 65 to the chamber 61. is supplied to the region where the plasma P is generated inside. On the other hand, high-frequency power of a predetermined power is applied to the antenna 63 from the high-frequency power supply 64a, and electromagnetic energy is radiated inside the chamber 61 through the transmission window 61a. Further, high-frequency power of a predetermined power is applied from the high-frequency power supply 64b to the mounting portion 62 on which the workpiece 100 is mounted, and an electric field is formed to accelerate ions directed from the plasma P toward the workpiece 100 .

Plasma P is generated by the electromagnetic energy radiated into the chamber 61, and the generated plasma P excites and activates the process gas G to generate plasma products such as neutral active species and ions. By supplying the generated plasma product to the processing object 100, the processing object 100 is plasma-processed.

FIG. 3 is a schematic cross-sectional view for illustrating the processing section 16 according to another embodiment.
The processing unit 16 is a microwave-excited plasma processing apparatus generally called a "CDE (Chemical Dry Etching) apparatus" or a "remote plasma apparatus". The processing unit 16 uses the plasma P to generate plasma products from the process gas G, and mainly uses radicals contained in the plasma products to process the workpiece 100 .

As shown in FIG. 3, the processing unit 16 includes, for example, a plasma generation unit 161, an exhaust unit 162 (corresponding to an example of a first exhaust unit), a microwave generation unit 163, a chamber 164 (an example of a first chamber). ), a mounting portion 165, and a gas supply portion 166 (corresponding to an example of a first gas supply portion).

The plasma generator 161 has, for example, a discharge tube 161a, an introduction waveguide 161b, and a transport tube 161c.
The discharge tube 161 a has a region for generating plasma P inside and is provided at a position separated from the chamber 164 . The discharge tube 161a has a tubular shape and can be made of a material that has a high transmittance to microwaves M and is difficult to etch. For example, discharge tube 161a can be formed from a dielectric such as alumina or quartz.

The introduction waveguide 161b is connected to the outside of the discharge tube 161a so as to be substantially orthogonal to the discharge tube 161a. A termination matcher 161b1 is provided at the end of the introduction waveguide 161b. A stub tuner 161b2 is provided on the inlet side (introduction side of the microwave M) of the introduction waveguide 161b.

An annular slot 161b3 is provided at the connecting portion between the introduction waveguide 161b and the discharge tube 161a. The microwave M propagated inside the introduction waveguide 161b is radiated inside the discharge tube 161a via the slot 161b3.

One end of the transport tube 161c is connected to the end of the discharge tube 161a opposite to the gas supply section 166 side. The other end of transport tube 161 c is connected to chamber 164 . The transport tube 161c is made of a material resistant to radicals contained in plasma products. The transport tube 161c is made of, for example, quartz, stainless steel, ceramics, fluororesin, or the like.

The exhaust unit 162 reduces the pressure inside the chamber 164 to a predetermined pressure. The exhaust section 162 can be connected to the bottom surface of the chamber 164 via the pressure control section 66a, for example. The exhaust section 162 can be similar to the exhaust section 66 described above, for example.

The microwave generator 163 is provided at the end of the introduction waveguide 161b opposite to the discharge tube 161a side. The microwave generator 163 generates a microwave M of a predetermined frequency (for example, 2.75 GHz) and radiates it toward the introduction waveguide 161b.

The chamber 164 has an airtight structure capable of maintaining an atmosphere pressure-reduced below atmospheric pressure. A side wall of the chamber 164 is provided with an opening 164a for loading and unloading the object 100 to be processed. A gate valve 164b is provided to open and close the opening 164a. The chamber 164 is connected to the chamber 71 of the transfer section 7 via a gate valve 164b.

Further, a straightening plate 164 c can be provided inside the chamber 164 . The straightening plate 164 c can be provided on the inner wall of the chamber 164 so as to be substantially parallel to the mounting surface of the mounting portion 165 . A gas containing radicals is introduced into the space between the current plate 164c and the ceiling of the chamber 164 via the transport pipe 161c. If the rectifying plate 164c is provided, it becomes easy to make the amount of radicals on the processing surface of the processing object 100 substantially uniform.

The mounting section 165 is provided inside the chamber 164 . The workpiece 100 is placed on the upper surface of the placing portion 165 . In this case, the workpiece 100 may be placed directly on the upper surface of the placement section 165, or may be placed on the placement section 165 via a support member (not shown) or the like. Further, a holding device such as an electrostatic chuck can be provided on the mounting portion 165 .

The gas supply unit 166 is connected to the end of the discharge tube 161a opposite to the chamber 164 side. The gas supply unit 166 supplies the process gas G inside the discharge tube 161a. A pressure control section 166a can be provided between the gas supply section 166 and the discharge tube 161a. The pressure controller 166a controls the pressure of the process gas G supplied inside the discharge tube 161a.

When subjecting the object 100 to plasma processing, the inside of the chamber 164 is decompressed to a predetermined pressure by the exhaust section 162 . At this time, the pressure inside the discharge tube 161a communicating with the chamber 164 is also reduced. Next, the process gas G having a predetermined pressure is supplied from the gas supply section 166 to the inside of the discharge tube 161a through the pressure control section 166a. Further, a microwave M having a predetermined power is radiated from the microwave generator 163 into the introduction waveguide 161b. The radiated microwave M propagates inside the introduction waveguide 161b and is radiated inside the discharge tube 161a through the slot 161b3.

Plasma P is generated by the energy of the microwave M radiated inside the discharge tube 161a. The generated plasma P excites and activates the process gas G to generate plasma products including radicals and ions.

A gas containing plasma products is supplied to the interior of the chamber 164 through the transport pipe 161c. At this time, short-lived ions cannot reach the inside of the chamber 164 , and long-lived radicals reach the inside of the chamber 164 . The gas containing radicals supplied to the interior of the chamber 164 is rectified by the rectifying plate 164c and reaches the processing surface of the workpiece 100, where plasma processing such as etching processing is performed. In this case, chemical treatment with radicals is mainly performed. Also, since ions used for physical processing are not supplied to the inside of the chamber 164, the processing surface of the processing object 100 is not damaged by the ions. Therefore, the processing section 16 is suitable for removing damage caused by etching processing using ions, for example.

In the above description, an inductively coupled plasma (ICP) processing apparatus and a CDE apparatus (remote plasma apparatus) have been described as examples of the processing section, but the processing section is limited to these plasma processing apparatuses. does not mean For example, the processing unit includes a capacitively coupled plasma (CCP) processing apparatus (e.g., parallel plate type RIE (Reactive Ion Etching) apparatus), other microwave excitation type plasma processing apparatus (e.g., SWP (Surface Wave Plasma (surface wave plasma) device) or the like may be used. Since a known technology can be applied to the basic configuration of other plasma processing apparatuses, detailed description thereof will be omitted.

Next, referring back to FIG. 1, the transfer section 7 will be described.
As shown in FIG. 1 , the transfer section 7 is provided between the processing section 6 ( 16 ) and the load lock section 5 . The transfer unit 7 transfers the processed material 100 between the processing unit 6 ( 16 ) and the load lock unit 5 .

FIG. 4 is a schematic cross-sectional view for illustrating the transfer section 7. As shown in FIG.
4 is a cross-sectional view of the transfer section 7 taken along the line AA in FIG.
As shown in FIG. 4, the transfer section 7 includes a chamber 71, a transfer section 72, an exhaust section 73 (corresponding to an example of a second exhaust section), and a gas supply section 74 (an example of a second gas supply section). equivalent).

The chamber 71 has an airtight structure capable of maintaining an atmosphere pressure-reduced below atmospheric pressure. Chamber 71 is connected to chamber 61 (164) via gate valve 61c (164b).

The transport section 72 is provided inside the chamber 71 . The transport unit 72 transfers the workpiece 100 between the processing unit 6 ( 16 ) and the load lock unit 5 . For example, the transport section 72 transports (carries in and carries out) the workpiece 100 to and from the chamber 61 (164) of the processing section 6 (16). The transport unit 72 can be, for example, a transport robot (for example, an articulated robot) having an arm that holds the workpiece 100 .

The exhaust unit 73 reduces the pressure inside the chamber 71 to a predetermined pressure. The exhaust section 73 can be connected to the bottom surface of the chamber 71 via the pressure control section 66a, for example.
The exhaust portion 73 can be, for example, similar to the exhaust portion 66 described above.
Based on the output of a pressure gauge (not shown) that detects the pressure inside the chamber 71, the pressure control unit 66a controls the pressure inside the chamber 71 to a predetermined pressure.

Here, as described above, the process gas G used in plasma processing includes, for example, a gas containing fluorine atoms, which is highly reactive. When the highly reactive gas flows from the interior of the chamber 61 (164) of the processing section 6 (16) to the interior of the chamber 71 of the transfer section 7, the highly reactive gas is exposed to the interior of the chamber 71. Contaminants may be generated by reaction with elements

In addition, by-products generated during plasma processing may adhere to the inner wall of the chamber 61 (164) of the processing section 6 (16) or elements exposed inside the chamber 61 (164). . Therefore, when an air current flowing from the inside of the chamber 61 (164) of the processing section 6 (16) toward the inside of the chamber 71 of the transfer section 7 is formed, the flow of the chamber 61 (164) of the processing section 6 (16) By-products separated from the inner wall or the like may enter the interior of the chamber 71 of the transfer section 7 along with the air current. By-products that have entered the chamber 71 of the delivery unit 7 become contaminants for the workpiece 100 .

Therefore, when the object 100 to be processed is carried into the chamber 61 (164) of the processing unit 6 (16) or unloaded from the chamber 61 (164) of the processing unit 6 (16), the exhaust unit 73 and the pressure control unit 66a attached to the chamber 71 work together to increase the pressure inside the chamber 71 so that the pressure inside the chamber 61 (164) of the processing unit 6 (16) (for example, plasma processing) pressure). For example, the internal pressure of the chamber 61 (164) of the processing section 6 (16) can be set to about 1×10 ⁻³ Pa to 1×10 ⁻² Pa.

In this case, the expression that the pressure inside the chamber 71 of the delivery unit 7 is substantially equal to that inside the chamber 61 (164) of the processing unit 6 (16) means that the pressure inside the chamber 71 is the same as the pressure inside the chamber 61. It means the range of pressure from pressure to 5×10 ⁻² Pa higher than the same pressure as the pressure inside the chamber 61 . By doing so, it is possible to effectively prevent highly reactive gases and by-products from entering the chamber 71 of the transfer section 7 .

In order to suppress the inflow of particles into the processing section 6 (16), the present inventors determined that the pressure in the chamber 71 of the transfer section 7 should be approximately equal to the pressure in the chamber 61 (164) of the processing section 6 (16). I also tried to make it equivalent. Specifically, the pressure inside the chamber 71 was maintained at 1×10 ⁻³ Pa to 5×10 ⁻³ Pa by evacuating the inside of the chamber 71 of the delivery unit 7 with the exhaust unit 73 .

As described above, even if the contaminants move from the chamber 61 (164) of the processing section 6 (16) to the chamber 71 of the delivery section 7, the volume of the exhaust section 73 is smaller than the volume of the chamber 71. If is large enough, it is considered that the exhaust part 73 exhausts the contaminants from the chamber 71 before they adhere to the object 100 to be processed, so that contamination by the contaminants can be eliminated.
However, it has been found that contaminants may actually adhere to the workpiece 100 inside the chamber 71 . When the workpiece 100 with contaminants adhered thereto is carried into the chamber 61 (164) of the processing section 6 (16) and plasma-treated, the quality of the product may be affected. In addition, when the object 100 to which contaminants are attached is carried outside from the plasma processing apparatus 1, there is a possibility that the processing in the subsequent process will be affected.

As a result of investigations by the present inventors, when the workpiece 100 is carried into or out of the chamber 61 (164) of the processing section 6 (16), the internal pressure of the chamber 71 is changed to We have found that contaminants are generated inside the chamber 71 when the pressure inside (164) is made substantially equal. That is, it has been found that when the pressure inside the chamber 71 is reduced, contaminants are generated from elements that are exposed inside the chamber 71 and contain organic substances.

As described above, the chamber 71 has an airtight structure capable of maintaining an atmosphere pressure-reduced below atmospheric pressure. Therefore, a sealing member such as an O-ring is used in the chamber 71 to form an airtight structure. The inventors of the present invention have made intensive investigations and obtained the following findings.
It has been found that the aforementioned sealing member contains an organic substance such as C ₁₆ H ₃₀ O ₄ . It has also been found that when the seal member containing organic matter is exposed to an atmosphere whose pressure is reduced below atmospheric pressure, the organic component of the seal member may evaporate and be released into the chamber 71 . In addition, the heat generated during the plasma processing may be transmitted to the chamber 71 and the temperature of the chamber 71 may reach approximately 50.degree. In such a case, the temperature of the sealing member increases, and the components of the sealing member are more likely to be released. Components of the seal member released into the interior of the chamber 71 become contaminants.

As a result of further studies, the inventors of the present invention have found that if the pressure inside the chamber 71 is controlled, the release of the components of the seal member can be suppressed, and thus the object 100 to be processed inside the chamber 71 can be prevented from being contaminated. We obtained the knowledge that it is possible to suppress the

FIG. 5 is the vapor pressure curve of C ₁₆ H ₃₀ O ₄ .
C ₁₆ H ₃₀ O ₄ is a component that is often contained in sealing members such as O-rings.
Points B1 and B2 in FIG. 5 are measured values, and a dotted line in FIG. 5 is an approximate curve based on points B1 and B2.
_In the lower region of the vapor pressure _curve , the components of _C16H30O4 are more likely to evaporate. _In the upper region of the vapor pressure _curve , the components of _C16H30O4 are difficult to evaporate. For example, after the material to be processed 100 is transferred to the chamber 61 (164) of the processing section 6 (16), if the pressure inside the chamber 71 is set to the upper region of the vapor pressure curve, the seal member can suppress the release of the components of

By the way, since the chamber 61 of the processing section 6 is exposed to plasma, it may be heated to about 80.degree. C. to 100.degree. In some cases, the workpiece 100 is plasma-processed while being heated to about 150.degree. C. to 300.degree. Therefore, the chamber 164 of the processing section 16 may also be heated to about 80°C to 100°C.
In the above case, since the chamber 71 is connected to the chamber 61 (164) through the gate valve 61c (164b), the temperature of the chamber 71 also rises to about 50.degree. C. to 70.degree.

For example, if the pressure inside the chamber 71 is set to 5×10 ⁻³ Pa or higher after the processing object 100 is transferred to the chamber 61 (164) of the processing section 6 (16), the temperature of the chamber 71 increases to Even if the temperature reaches about 50° C., evaporation of the C ₁₆ H ₃₀ O ₄ component can be suppressed.

However, depending on the type of plasma processing, processing conditions, etc., the temperature of the chamber 71 may become even higher.
As a result of studies by the present inventors, it was found that the pressure inside the chamber 71 after the transfer of the workpiece 100 to the chamber 61 (164) of the processing section 6 (16) was 1×10 ⁻¹ Pa or more. For example, even if the type of plasma treatment, treatment conditions, etc. are changed, it is possible to substantially eliminate the evaporation of the C ₁₆ H ₃₀ O ₄ component.

If the pressure inside the chamber 71 is made too high, the by-product adhering to the inner wall of the chamber 61 (164) is removed by the airflow from the chamber 71 toward the chamber 61 (164) of the processing section 6 (16). There is a risk of peeling off or floating of by-products inside the chamber 61 (164). Therefore, it is preferable that the pressure inside the chamber 71 is about 8×10 ⁻³ Pa to 5×10 ⁻² Pa when the object 100 to be processed is carried in and out from the processing section 6 . The pressure inside the chamber 71 of the delivery section 7 is determined to be slightly higher than the pressure inside the chamber 61 (164) of the processing section 6 (16) within the above pressure range.

The pressure of the chamber 71 can be controlled by the exhaust section 73 and the pressure control section 66a, but it is difficult to quickly increase the lowered pressure.
Therefore, as shown in FIG. 4, a gas supply section 74 is provided in the delivery section 7 according to the present embodiment.
The gas supply unit 74 supplies the gas G1 into the chamber 71 via the flow control unit 74a. The flow controller 74a can be, for example, a mass flow controller (MFC).

The gas G<b>1 can be, for example, a gas that does not readily react with the workpiece 100 and elements exposed inside the chamber 71 . For example, the gas G1 can be nitrogen gas, rare gas such as argon gas, or a mixed gas thereof.

Further, the gas G1 is supplied to control the pressure inside the chamber 71, and the amount of pressure control is small, so the amount of the gas G1 supplied to the inside of the chamber 71 is very small. For example, the flow rate of gas G1 is 10 sccm or more and 1000 sccm or less.

Therefore, a gas that reacts with contaminants including organic matter may be supplied as gas G1, or a gas that reacts with contaminants including organic matter may be added to the above-described nitrogen gas or the like and supplied. The gas that reacts with organic contaminants can be, for example, ozone gas. If the gas G1 is ozone gas or contains ozone gas, even if contaminants containing organic substances are generated, at least part of the generated contaminants can be decomposed.

By the way, the sealing member used in the processing section 6 is the same as the sealing member used in the transfer section 7 . Also, the pressure inside the chamber 61 (164) is maintained at a pressure at which the components of the seal member may evaporate, except when the plasma treatment is performed. Therefore, the components of the seal member may evaporate, be discharged into the chamber 61 (164), and adhere to the workpiece 100. FIG. However, as a result of the inventor's earnest investigation, the probability of contaminants adhering inside the chamber 71 was higher than the probability of contaminants adhering inside the chamber 61 (164).

Presumably, the process gas is introduced into the interior of the chamber 61 (164) to perform plasma processing, so that contaminants (vaporized components of the seal member) are released from the interior of the chamber 61 (164) along with the process gas. This is probably because it is discharged. In other words, it is considered that the adhesion of contaminants to the workpiece 100 can be suppressed by increasing the pressure in the chamber by introducing the gas.

FIG. 6 is a timing chart illustrating the supply of gas G1.
T1 in FIG. 6 is the timing to start carrying the workpiece 100 from the chamber 71 of the delivery section 7 to the chamber 61 (164) of the processing section 6 (16).

T2 in FIG. 6 is the timing to start unloading the workpiece 100 from the chamber 61 (164) of the processing section 6 (16) to the chamber 71 of the transfer section 7. FIG.

When there is no workpiece 100 to be processed, the plasma processing apparatus 1 is in a standby state. When the plasma processing apparatus 1 is in the standby state, the inside of the chamber 51 of the load lock section 5 is evacuated by the exhaust section 52 and maintained at a pressure of approximately 1×10 ⁻² Pa to 1×10 ⁻¹ Pa. In this embodiment, it is 5×10 ⁻² Pa, for example.
The internal pressure of the chamber 71 of the transfer section 7 is maintained at a pressure of 5×10 ⁻³ Pa or more capable of suppressing evaporation of the C ₁₆ H ₃₀ O ₄ component. Specifically, the controller 2 controls the pressure control unit 66a attached to the chamber 71 based on the output of a pressure gauge (not shown) that detects the pressure inside the chamber 71, so that the pressure inside the chamber 71 is is set to a pressure of 5×10 ⁻³ Pa or more.
The inside of the chamber 61 of the processing section 6 is evacuated by the exhaust section 66 and maintained at a pressure of 1×10 ⁻³ Pa to 1×10 ⁻² Pa. In this embodiment, it is 1×10 ⁻³ Pa, for example.

When processing the workpiece 100 , the pressure inside the chamber 51 of the load lock section 5 is made equal to the atmospheric pressure by venting the inside of the chamber 51 . The transport unit 4 takes out the workpiece 100 inside the storage unit 3 and carries it into the chamber 51 of the load lock unit 5 ((1) in FIG. 6).

After the workpiece 100 is loaded into the chamber 51, the pressure inside the chamber 51 is reduced. When the pressure inside the chamber 51 is reduced to a predetermined pressure, the gas G1 is supplied from the gas supply unit 74 to the inside of the chamber 71 to increase the pressure inside the chamber 71 to 1×10 ⁻¹ Pa or higher. The predetermined pressure is 1×10 ⁻² Pa or more and less than 1×10 ⁻¹ Pa. In this embodiment, it is 5×10 ⁻² Pa, for example.
When the pressure inside the chamber 51 and the pressure inside the chamber 71 reach the above pressures, the gate valve 51a is opened. Then, the workpiece 100 is carried into the chamber 71 by the transfer section 72 ((2) in FIG. 6).

The chamber 51 communicates with the space outside the plasma processing apparatus 1 . Therefore, air in the external space is taken into the chamber 51 when the object 100 to be processed is transferred. The air in the external space may contain water vapor and particles. By making the pressure inside the chamber 71 higher than the pressure inside the chamber 51 , it is possible to suppress the flow of water vapor and particles from the chamber 51 to the chamber 71 .

After the object 100 to be processed is transferred into the chamber 71, the gate valve 51a is closed. When the gate valve 51a is closed, the supply of the gas G1 into the chamber 71 is stopped. In addition, the pressure reduction inside the chamber 51 is maintained.
When the pressure inside the chamber 71 reaches, for example, 5×10 ⁻² Pa, the gate valve 61c is opened. Then, the workpiece 100 is carried into the chamber 61 (164) by the transfer section 72 (T1 in FIG. 6).

Inside the chamber 61 (164) of the processing section 6 (16), a plasma product is generated from highly reactive gas using plasma to process the object 100 to be processed. For this reason, if highly reactive gas remains inside the chamber 61 (164), or if by-products generated during plasma processing are exposed to the inner wall of the chamber 61 (164) of the processing unit 6 (16), etc. may be attached to If the internal pressure of the chamber 71 is made substantially equal to the internal pressure of the chamber 61 (164) of the processing section 6 (16), the highly reactive gas and by-products are prevented from entering the chamber of the transfer section 7. Intrusion into the interior of 71 can be suppressed.

After the object 100 is loaded into the chamber 61 (164), the gate valve 61c is closed. A period from when the gate valve 61c is opened to when it is closed is defined as a loading period T1a of the object 100 to be processed. After the gate valve 61c is closed, the gas G1 is supplied from the gas supply section 74 to the inside of the chamber 71 . Thereby, the pressure inside the chamber 71 is maintained at 1×10 ⁻¹ Pa or higher.

After the internal pressure of the chamber 61 (164) is reduced to a predetermined pressure, the gas supply section 65 (166) is controlled to reduce the internal pressure of the chamber 61 (164) to the pressure for plasma processing. supply G. The pressure for plasma processing is about 1×10 ⁻¹ Pa to 10 Pa. In this embodiment, it is 1 Pa, for example. The predetermined pressure is 1×10 ⁻³ Pa to 1×10 ⁻² Pa.

When the pressure inside the chamber 61 (164) reaches a pressure for performing plasma processing, a high frequency voltage is applied to the antenna 63 from the high frequency power supply 64a to generate plasma P. FIG. A plasma product is generated from the process gas G using the plasma P, and the object 100 is processed using the radicals contained in the plasma product.

When the plasma processing is completed, the application of the high frequency voltage from the high frequency power supply 64a and the supply of the process gas G are stopped. The pressure inside the chamber 61 (164) is reduced to 1×10 ⁻³ Pa to 1×10 ⁻² Pa. In this embodiment, the pressure inside the chamber 61 (164) is reduced to 1×10 ⁻³ Pa, for example.

When the pressure inside the chamber 61 (164) reaches 1×10 ⁻³ Pa, the supply of the gas G1 from the gas supply section 74 is stopped. Then, when the pressure inside the chamber 71 reaches, for example, 5×10 ⁻² Pa, the gate valve 61c is opened. The workpiece 100 is carried out from the chamber 61 (164) by the transfer section 72 (T2 in FIG. 6).

After the material to be processed 100 is transported into the chamber 71 by the transport unit 72, the gate valve 61c is closed. A period from when the gate valve 61c is opened to when the gate valve 61c is closed is defined as a carry-out period T2a of the object 100 to be processed. After the carry-out period T2a, the gas G1 is supplied to the inside of the chamber 71 from the gas supply section 74 .

When the pressure inside the chamber 71 reaches 1×10 ⁻¹ Pa or higher, the gate valve 51a is opened and the workpiece 100 is transferred to the chamber 51 by the transfer section 72 ((4) in FIG. 6).

After the material to be processed 100 is transferred into the chamber 51, the gate valve 51a is closed. In the transfer section 7, the amount of gas G1 supplied to the interior of the chamber 71 is reduced. The supply amount of the gas G1 is such that the pressure inside the chamber 71 is 1×10 ⁻² Pa or higher. For example, the supply amount of the gas G1 is set to 0.5 times. By doing so, it is possible to suppress the components of the seal member from evaporating and being released into the chamber 71 . In addition, even if contaminants (components of the vaporized seal member) are generated when the object 100 to be processed is carried out from the chamber 61 (164), by supplying the gas G1, the contaminants can be removed together with the gas G1 into the chamber 71. can be discharged to the outside of

In addition to reducing the amount of gas G1 supplied to the inside of the chamber 71, the pressure control unit 66a attached to the chamber 71 may also reduce the exhaust amount of the exhaust unit 73. In other words, the gas supply unit 74 and the pressure control unit 66a may cooperate to maintain the pressure inside the chamber 71 at 1×10 ⁻² Pa or higher. By doing so, the usage amount of the gas G1 can be reduced.

In the load lock section 5, the inside of the chamber 51 is vented to make the pressure inside the chamber 51 atmospheric pressure. When the pressure inside the chamber 51 becomes approximately the same as the atmospheric pressure, the transfer section 4 takes out the processing object 100 from the inside of the chamber 51 and stores it in the storage section 3 ((5) in FIG. 6). Then, the next workpiece 100 is transported to the load lock section 5 ((6) in FIG. 6).

During the period T1a during which the material to be processed 100 is carried in after T1 and the period during which the material to be processed 100 is carried out after T2 is T2a, the pressure of the delivery section 7 is temporarily set to the pressure included in the lower region of the vapor pressure curve in FIG. . Specifically, when the gate valve 61 c is opened, the gas inside the chamber 71 flows into the processing section 6 . Therefore, the internal pressure of the chamber 71 is approximately equal to the internal pressure of the chamber 61 (164) of the processing unit 6 (16) (for example, 1×10 ⁻³ Pa, which is a predetermined pressure immediately before plasma processing). The pressure is reduced to equality. for that reason. During the carry-in period T1a and the carry-out period T2a, the components of the seal member evaporate and are released into the chamber 71 .

However, after the carry-in period T1a and the carry-out period T2a have elapsed, the gate valve 61c (164b) closes the chamber 71 of the delivery section 7 and the chamber 61 (164) of the processing section 6 (16). Then, the gas supply unit 74 supplies the gas G1 to the inside of the chamber 71 of the delivery unit 7, so that the pressure inside the chamber 71 is 5×10 ⁻³ Pa or more, preferably 1×10 ⁻¹ Pa or more. be done. Therefore, it is possible to suppress the evaporation of the components of the seal member.

Further, even if the pressure inside the chamber 71 of the delivery unit 7 and the chamber 61 of the processing unit 6 is set to the pressure at which the components of the seal member can evaporate or less, the introduction of the gas into the delivery unit 7 reduces contaminants (vaporization). component of the sealing member) can be suppressed from adhering to the object 100 to be processed. The interiors of the chambers 71 and 61 are evacuated so as to maintain a predetermined reduced-pressure atmosphere. The exhaust speed (L/min) of the exhaust portion 73 and the exhaust portion 66 is determined. When the gas G1 is supplied to the interiors of the chambers 71 and 61, the pressure in the chamber 71 rises and the amount of the gas G1 discharged per unit volume increases. As a result, it seems that the inside of the chamber is evacuated by the amount of gas G1 supplied. In other words, this exhaust allows contaminants to be exhausted together with the gas G1.

Moreover, as can be seen from FIG. 6, the pressure inside the chamber 71 is equal to or lower than the pressure at which the component of the sealing member can evaporate, that is, the pressure inside the chamber 61 (164) of the processing section 6 (16). It is possible to shorten the period in which the pressure is reduced so that the pressures are substantially the same. Therefore, it is possible to suppress the evaporation of the components of the seal member.
Further, even if the components of the sealing member evaporate inside the chamber 71, by supplying the gas G1, the contaminants (vaporized components of the sealing member) are removed together with the gas G1 in the same way as the chamber 61 (164). 71 can be discharged to the outside.

If the chamber 71 does not contain the workpiece 100 for a long time, the pressure control unit 66a attached to the chamber 71 may be controlled to reduce the exhaust amount of the exhaust unit 73. FIG. By reducing the exhaust amount of the exhaust part 73, the amount of the gas G1 required to set the internal pressure of the chamber 71 to 1×10 ⁻² Pa or more can be reduced. The time during which there is no workpiece 100 inside the chamber 71 is, for example, the time from when the supply of the gas G1 is stopped until the pressure inside the chamber 71 reaches 1×10 ⁻² Pa. .

The above procedure can be performed by the controller 2 controlling the transfer section 72, the exhaust section 73, and the gas supply section 74, for example.
For example, when the transfer unit 72 transfers (carries in and out) the workpiece 100, the controller 2 controls the exhaust unit 73 to reduce the pressure inside the chamber 71 to the pressure inside the chamber 61 (164). Make it approximately equal to the pressure. For example, the controller 2 controls the gas supply unit 74 to supply the gas G<b>1 into the chamber 71 when the transfer of the workpiece 100 by the transfer unit 72 is completed.
For example, the controller 2 makes the pressure inside the chamber 71 higher than the pressure inside the chamber 61 (164) by supplying the gas G1.
For example, the controller 2 sets the pressure inside the chamber 71 to 5×10 ⁻³ Pa or more, preferably 1×10 ⁻¹ Pa or more, by supplying the gas G1.

Moreover, as explained above, the plasma processing method according to the present embodiment can include the following steps.
A step of subjecting the workpiece 100 to plasma treatment in a first region having an atmosphere pressure-reduced below atmospheric pressure. The first area is, for example, the interior of chamber 61 (164).
A step of transporting the workpiece 100 between the first area and a second area separated from the first area. The second area is, for example, the interior of chamber 71 .
When the object 100 to be processed is transferred, the pressure of the atmosphere in the second area is made substantially equal to the pressure of the atmosphere in the first area.
When the transportation of the processing object 100 is completed, the gas G1 is supplied to the second area.
For example, by supplying the gas G1 after the object 100 is transferred, the pressure of the atmosphere in the second region is made higher than the pressure of the atmosphere in the first region when the object 100 is transferred. do.
For example, by supplying the gas G1, the pressure of the atmosphere in the second region is set to 5×10 ⁻³ Pa or more, preferably 1×10 ⁻¹ Pa or more.
Note that the details of each step can be the same as those described above, and detailed description thereof will be omitted.

The present embodiment has been exemplified above. However, the invention is not limited to these descriptions.
Appropriate design changes made by those skilled in the art with respect to the above embodiments are also included in the scope of the present invention as long as they have the features of the present invention.
For example, the shape, size, material, arrangement, number, etc. of each element provided in the plasma processing apparatus 1 are not limited to those illustrated and can be changed as appropriate.
Moreover, each element provided in each of the above-described embodiments can be combined as much as possible, and a combination thereof is also included in the scope of the present invention as long as it includes the features of the present invention.

In this embodiment, the pressure controller 66a attached to the chamber 71 controls the internal pressure of the chamber 71 to be maintained at 5×10 ⁻³ Pa or higher. However, it is not limited to this. For example, the exhaust part 73 may be a combination of a turbo-molecular pump and a dry pump, and an exhaust port connected to the dry pump may be provided at the bottom of the chamber 71 . When the object 100 to be processed is not inside the chamber 71 for a long time, the inside of the chamber 71 may be evacuated by a dry pump. Alternatively, when the pressure reaches 5×10 ⁻³ Pa, the exhaust section 73 may be stopped.

Reference Signs List 1 plasma processing apparatus 2 controller 3 storage unit 4 transfer unit 5 load lock unit 6 processing unit 7 transfer unit 71 chamber 72 transfer unit 73 exhaust unit 74 gas supply unit 100 object to be processed G Process gas, G1 gas, P plasma

Claims (7)

a first chamber that maintains an atmosphere reduced to a pressure lower than the atmospheric pressure, and in which an object to be processed can be placed;
a first exhaust unit capable of decompressing the inside of the first chamber to a predetermined pressure;
a plasma generator capable of generating the plasma;
a first gas supply unit capable of supplying a process gas to a region where the plasma is generated inside the first chamber;
a second chamber connected to the first chamber via a gate valve and capable of maintaining an atmosphere reduced below atmospheric pressure;
a transfer unit provided inside the second chamber and capable of transferring the object to be processed between the first chamber and the second chamber;
a second exhaust unit capable of decompressing the inside of the second chamber to a predetermined pressure;
a second gas supply unit capable of supplying gas to the inside of the second chamber;
a controller capable of controlling the transport section, the second exhaust section, and the second gas supply section;
with
The controller is
When the object to be processed is transported by the transport unit, the second exhaust unit is controlled so that the pressure inside the second chamber is substantially equal to the pressure inside the first chamber. so that
A plasma processing apparatus for supplying the gas to the inside of the second chamber by controlling the second gas supply unit when the transfer of the object to be processed by the transfer unit is completed. The controller supplies the gas after the object to be processed has been transported between the first chamber and the second chamber by the transport unit, so that the inside of the second chamber 2. The plasma processing apparatus according to claim 1, wherein the pressure is set higher than the pressure inside said first chamber during transfer of said object to be processed. 3. The plasma processing apparatus according to claim 1, wherein the controller sets the pressure inside the second chamber to 5×10 ⁻³ Pa or more by supplying the gas. The controller controls the second exhaust unit to set the pressure inside the second chamber to 5×10 ⁻³ Pa or more when the object to be processed does not exist in the second chamber. The plasma processing apparatus according to claim 3. A plasma processing method for plasma processing an object to be processed,
plasma processing the object in a first region having an atmosphere reduced below atmospheric pressure;
a step of conveying the processed material between the first region and a second region separated from the first region;
with
When the object to be processed is transported, the pressure of the atmosphere in the second region is made substantially equal to the pressure of the atmosphere in the first region,
A plasma processing method, wherein a gas is supplied to the second region when the transportation of the processing object is completed. By supplying the gas after the object to be processed is transferred, the pressure of the atmosphere in the second region is made higher than the pressure of the atmosphere in the first region when the object to be processed is transferred. 6. The plasma processing method according to claim 5. 7. The plasma processing method according to claim 5, wherein the pressure of the atmosphere in the second region is set to 5×10 ⁻³ Pa or more by supplying the gas.

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