JP2003318162A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device that can be improved in safety as compared with the conventional device by surely and easily detecting the electrically connected state between a high-frequency power supply section and a processing section. <P>SOLUTION: Both ends of a coaxial cable 30 are respectively connected to the connector 10a of a matching box 10 and the connector 40a of the high-frequency power supplying section 40. When electrical communication exists between the connectors 10a and 40a, a DC voltage signal is transmitted from a signal supplying mechanism 100 to a signal detecting mechanism 200 through the cable 30 and a relay 203 is actuated by the signal. An interlocking mechanism (I/L) 42 controls so that a high-frequency power source 41 may be turned on only in the case where the relay 203 is actuated by the DC voltage signal. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus for generating plasma and performing etching processing, film forming processing or the like on an object to be processed such as a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, a plasma processing apparatus has been widely used in which plasma is generated and the plasma is applied to an object to be processed to perform a predetermined process.

For example, in the field of manufacturing semiconductor devices, when forming a fine circuit structure of a semiconductor device, plasma is applied to a substrate to be processed such as a semiconductor wafer to perform etching or film formation.

Among such plasma processing apparatuses, a plasma processing apparatus for generating plasma by the action of high-frequency power is a processing unit including a vacuum chamber or the like for processing plasma by causing plasma to act on an object to be processed housed therein. High-frequency power supply unit configured to supply high-frequency power for generating a gas, an exhaust system including a vacuum pump for exhausting the inside of the vacuum chamber, a processing gas supply for supplying a processing gas into the vacuum chamber It is composed of the system.

A matching unit for impedance matching is provided in the processing unit, and the matching unit provided in the processing unit and the high frequency power source of the high frequency power supply unit are coaxial cables or the like. It is connected by a connection cable.

[0006]

Among the above-described plasma processing apparatuses, the plasma processing apparatus used for manufacturing semiconductor devices is generally arranged in a so-called clean room in a clean atmosphere. However, even in the same clean room, a clean room with high cleanliness requires high construction cost and high maintenance cost. Therefore, it is necessary to dispose the clean room close to the processing part in the parts other than the processing part of the plasma processing apparatus. In many cases, a non-existing portion, for example, a high-frequency power supply unit or the like is arranged in a so-called maintenance room or the like having a lower cleanness than the processing unit. In such a case, the length of the coaxial cable for electrically connecting the high frequency power supply unit and the processing unit is considerably long, and may be 10 meters or more.

Therefore, in order to visually confirm whether or not both ends of the coaxial cable are securely connected to the high-frequency power supply section and the processing section, an operator moves between them to confirm. It has to be done and requires complicated work.

Further, for example, when electrical continuity cannot be obtained or is insufficient because the conductor in the coaxial cable is in a broken state or a semi-broken state, it is visually inspected from the outside. It is difficult to detect it depending on the situation.

On the other hand, it is dangerous to start the high-frequency power supply in the state where the high-frequency power supply section and the processing section are not securely connected by the coaxial cable, and from the viewpoint of safety, It is necessary to avoid starting high-frequency power supply in such a state as much as possible. Therefore, various safety measures have been taken conventionally, but it is desired to further improve safety.

The present invention has been made in response to such a conventional situation, and can reliably and easily detect the electrical connection state between the high frequency power supply section and the processing section.
An object of the present invention is to provide a plasma processing apparatus that can improve safety more than ever before.

[0011]

That is, according to the first aspect of the present invention, there is provided a processing section having a vacuum chamber for applying plasma to an object to be processed contained therein, and a high frequency for generating the plasma. A high frequency power supply for supplying electric power, electrically connecting the high frequency power supply and the processing unit,
A connection cable that supplies high-frequency power from the high-frequency power source to the processing unit; signal supply means that supplies a connection detection signal separable from the high-frequency power to the connection cable from one end side of the connection cable; From the other end side of the signal detection means for detecting the connection detection signal,
And a control unit that controls the supply of high-frequency power from the high-frequency power source based on the detection result of the signal detection unit.

The invention according to claim 2 is the plasma processing apparatus according to claim 1, characterized in that the signal supply means is configured to supply a DC signal as the connection detection signal.

According to a third aspect of the invention, in the plasma processing apparatus according to the second aspect, the signal detecting means includes a separating means for separating the DC signal from the signal supplying means and the high frequency power. It is characterized by

According to a fourth aspect of the present invention, in the plasma processing apparatus according to the third aspect, the signal detection means detects the voltage value of the DC signal from the signal supply means to detect the connection state by the connection cable. It is characterized by

According to a fifth aspect of the present invention, in the plasma processing apparatus according to any one of the first to fourth aspects, the signal supply means is provided on the processing section side, and the signal detection means is provided on the high frequency power supply side. It is characterized by being.

According to a sixth aspect of the present invention, in the plasma processing apparatus according to any one of the first to fifth aspects, a matching unit is provided in the processing unit, and the connection cable is connected to the matching unit. Characterize.

According to a seventh aspect of the invention, in the plasma processing apparatus according to the sixth aspect, the signal detecting means is provided in a box provided with the matching box.

According to an eighth aspect of the present invention, in the plasma processing apparatus according to any one of the first to seventh aspects, the processing section comprises:
It is characterized in that it is arranged in a room having a higher degree of cleanliness than the room in which the high frequency power supply is arranged.

According to a ninth aspect of the present invention, in the plasma processing apparatus according to any one of the first to eighth aspects, the connection cable is connected to the high frequency power source and the processing section.
A cover that covers the connection portion is detachably provided, and high-frequency power is supplied from the high-frequency power source only when the sensor detects that the cover is attached. And

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to the drawings regarding an embodiment in which the present invention is applied to an etching apparatus.

FIG. 1 schematically shows the overall structure of a plasma processing apparatus (etching apparatus) according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is made of a material such as aluminum, The figure shows a cylindrical vacuum chamber that is configured to be airtightly closed and that constitutes a processing unit.

The vacuum chamber 1 is connected to a ground potential. Inside the vacuum chamber 1, there is provided a mounting table 2 which is made of a conductive material such as aluminum in a block shape and which also serves as a lower electrode. ing.

The mounting table 2 is supported in the vacuum chamber 1 through an insulating plate 3 made of ceramic or the like, and an electrostatic chuck 4 is provided on the mounting surface of the mounting table 2 on which the semiconductor wafer W is mounted. . The electrostatic chuck 4 has a structure in which an electrostatic chuck electrode 4a is interposed in an insulating film 4b made of an insulating material, and a DC power supply 5 is connected to the electrostatic chuck electrode 4a. .

Inside the mounting table 2, a heat medium passage 6 for circulating an insulating fluid as a heat medium for temperature control, and a temperature control gas such as helium gas are provided for the semiconductor wafer W. A gas flow path 7 is provided for supplying the gas to the back surface of the.

Then, by circulating an insulating fluid controlled to a predetermined temperature in the heat medium flow path 6, the mounting table 2
Is controlled to a predetermined temperature, and a temperature control gas is supplied between the mounting table 2 and the back surface of the semiconductor wafer W through the gas flow path 7 to promote heat exchange between them. The wafer W can be controlled to a predetermined temperature accurately and efficiently.

Further, a focus ring 8 made of a conductive material or an insulating material is provided on the outer periphery above the mounting table 2, and high frequency power is supplied to substantially the center of the mounting table 2. Is connected to the power supply line 9.
A matching box 11 provided in a matching box 10 is connected to the power supply line 9.

The matching box 10 is provided in the lower part or the upper part of the vacuum chamber 1. Further, the matching box 11 of the matching box 10 is connected to the high frequency power supply (R) of the high frequency power supply unit 40 via the coaxial cable 30.
F power source) 41 is connected, and the high frequency power source 41 supplies high frequency power having a predetermined frequency, for example, a frequency in the range of 13.56 to 150 MHz.

Outside the focus ring 8 described above,
An exhaust ring 12 having an annular shape and having a large number of exhaust holes is provided, and through the exhaust ring 12,
The exhaust system 50 connected to the exhaust port 13 is configured to perform vacuum exhaust of the processing space in the vacuum chamber 1. The exhaust system 50 is composed of a vacuum pump for exhausting, a pressure control device for controlling pressure, and the like.

On the other hand, a shower head 15 is provided on the ceiling wall of the vacuum chamber 1 above the mounting table 2 so as to face the mounting table 2 in parallel.
5 is grounded. Therefore, the mounting table 2 and the shower head 15 function as a pair of electrodes (upper electrode and lower electrode).

The shower head 15 is provided with a large number of gas discharge holes 16 on its lower surface, and has a gas introducing portion 17 on its upper portion. Then, a gas diffusion space 18 is formed inside thereof. A gas supply pipe 19 is connected to the gas introduction unit 17, and a processing gas supply system 60 is connected to the other end of the gas supply pipe 19.

The processing gas supply system 60 comprises a gas supply source for supplying various processing gases, for example, a processing gas for etching, a mass flow controller (MFC) for controlling the gas flow rate, and the like. .

On the other hand, around the outside of the vacuum chamber 1, an annular magnetic field forming mechanism (ring magnet) 20 is arranged concentrically with the vacuum chamber 1, and processing between the mounting table 2 and the shower head 15 is performed. It is designed to create a magnetic field in space. The entire magnetic field forming mechanism 20 can be rotated around the vacuum chamber 1 at a predetermined rotation speed by a rotating mechanism 21.

Of the above construction, the vacuum chamber 1, the matching box 10, the magnetic field forming mechanism 20 and the rotating mechanism 21.
Etc., which constitute a processing unit, are arranged in a clean room with a relatively high degree of cleanliness. Further, the high frequency power supply unit 40 is arranged in a clean room (so-called maintenance room) having a lower cleanness than the processing unit including the vacuum chamber 1 and the like. And between these,
Connector 1 whose one end is provided in the matching box 10
0a and the other end is connected by a coaxial cable 30 connected to a connector 40a provided in the high frequency power supply unit 40.

Further, in this embodiment, in order to detect whether or not the electrical connection by the coaxial cable 30 is surely made, the matching box 10 is provided with a signal supply mechanism 100, and high frequency power is supplied. The supply unit 40 is provided with a signal detection mechanism 200.

The signal supply mechanism 100 comprises a choke coil 101 for cutting off high frequency power components, a capacitor 102, a DC power supply 103, etc., and a DC voltage signal from the DC power supply 103 is used as a connection detection signal for the connector 10a. It is configured to be supplied to the coaxial cable 30 via. The matching unit 11 is provided with a capacitor (not shown) for impedance matching, and this capacitor prevents a DC voltage signal from the DC power supply 103 from leaking to the mounting table 2 side.

On the other hand, the signal detection mechanism 200 is composed of a choke coil 201 for blocking high frequency power components, a capacitor 202, a relay 203, etc., and detects the connection supplied from the signal supply mechanism 100 to the coaxial cable 30. A DC voltage signal as a signal is detected via the connector 40a. A capacitor 43 is provided between the connector 40a to which the coaxial cable 30 is connected and the high frequency power supply 41. With this capacitor 43, a DC voltage signal from the DC power supply 103 is transmitted to the high frequency power supply 41 side. Leakage is prevented.

Both ends of the above-mentioned coaxial cable 30 are connected to the connector 10a of the matching box 10, respectively.
Connected to the connector 40a of the high frequency power supply unit 40,
When there is electrical conduction between them, the DC voltage signal from the signal supply mechanism 100 side is transmitted to the signal detection mechanism 200 side via the coaxial cable 30, and the relay 203 is caused by this DC voltage signal. It is designed to work. The contact point of the relay 203 is an interlock mechanism (I / L) 42 for controlling on / off of the high frequency power source 41.
And the interlock mechanism (I / L) 42 controls to turn on the high frequency power supply 41 only when the relay 203 is operated by the DC voltage signal.

Therefore, for example, when both ends of the coaxial cable 30 are not connected to the connectors 10a and 40a and electrical continuity is not obtained, or both ends of the coaxial cable 30 are connected to the connectors 10a and 40a. However, if there is a disconnection in the middle and electrical continuity is not obtained, the high frequency power supply 41 will not be turned on, and there is a risk that the high frequency power supply 41 will be turned on in such a state. It can be avoided.

In the above embodiment, the signal supply mechanism 100 is provided on the processing section side (matching box 10).
The case where the signal detection mechanism 200 is provided on the high-frequency power supply unit 40 side has been described. On the contrary, the signal supply mechanism 100 is provided on the high-frequency power supply unit 40 side and the signal is provided on the processing unit side (matching box 10). The detection mechanism 200 may be provided.

Further, in the above embodiment, the case where the relay 203 is operated by the DC voltage signal and the presence or absence of the DC voltage signal is detected by the relay 203 is described. The configuration is not limited to this, and any type may be used. For example, like the signal detection mechanism 200a shown in FIG. 2, the voltage measurement mechanism 210 and the voltage determination mechanism 211 are provided, the voltage value of the DC voltage signal transmitted via the coaxial cable 30 is measured, and this DC voltage signal Only when the voltage value is equal to or higher than a preset predetermined value, the interlock mechanism (I
/ L) 42 to send the ON signal to operate the high-frequency power source 41, for example, even when the coaxial cable 30 is in a semi-disconnected state and the electrical conduction state is not sufficient. It is possible to reliably avoid the risk that the high frequency power supply 41 is turned on in this state.

In each of the above embodiments, the case where the DC voltage signal is used as the signal separable from the high frequency power has been described. However, it is not always necessary to use the DC voltage signal. Other signals can be used as long as they are signals that can be separated from high frequency power, such as low frequency high frequency signals.

By the way, FIG. 3 schematically shows a schematic configuration of a connecting portion between the above-mentioned coaxial cable 30 and the connector 10a of the matching box 10. As shown in the figure, the coaxial cable 30 includes a connector 10a.
A connector 31 and a cover 32 that are connected to the connector 31 are provided. Then, the connector 10a and the connector 31 are connected, the cover 32 is attached to the matching box 10 with a plurality of screws 33, and the connector 10a and the connector 3 are attached.
The connecting portion with 1 is covered with a cover 32.

Further, the cover 32 is provided with a pin 34, the cover 32 is attached to the matching box 10, and when the pin 34 is inserted into the through hole 10b provided on the side of the matching box 10, the sensor 10c is operated. The insertion of the pin 34 into the through hole 10b is detected.

Then, the pin 3 by this sensor 10c
The high frequency power supply 41 is configured to be turned on only when there is a detection signal of 4. Further, the cover and the sensor having the same configuration as described above are also provided on the other end side of the coaxial cable 30, that is, at the connection portion of the high frequency power supply unit 40 with the connector 40a.

Therefore, the high-frequency power supply 41 is substantially only when both the detection signal from the sensor 10c and the connection detection signal from the signal detection mechanism 200 described above are detected, that is, these AND conditions are satisfied. It is supposed to be turned on only when it is done.

With this configuration, the safety can be further improved, and in particular, the connector 10a and the connector 3 are erroneously mistaken while the high frequency power supply 41 is turned on.
When trying to remove 1 and 1, the high frequency power supply 41 is turned off when the cover 32 is removed, so that it is possible to prevent the occurrence of troubles due to such an erroneous operation.

Next, the procedure of the etching process by the etching apparatus configured as described above will be described.

First, a gate valve (not shown) provided in the vacuum chamber 1 is opened, and a transfer mechanism (not shown) is provided via a load lock chamber (not shown) arranged adjacent to the gate valve. The semiconductor wafer W is loaded into the vacuum chamber 1 and mounted on the mounting table 2. Then, a predetermined voltage is applied from the DC power supply 5 to the electrostatic chuck electrode 4a of the electrostatic chuck 4, and the semiconductor wafer W is attracted by the Coulomb force or the like.

After that, the transfer mechanism is evacuated to the outside of the vacuum chamber 1, the gate valve is closed, and the vacuum pump of the exhaust system 50 exhausts the inside of the vacuum chamber 1 through the exhaust port 13 while controlling the pressure.

After the inside of the vacuum chamber 1 reaches a predetermined degree of vacuum, the processing gas supply system 6 is placed inside the vacuum chamber 1.
From 0, a predetermined etching gas is introduced at a predetermined flow rate, and the inside of the vacuum chamber 1 has a predetermined pressure, for example, 1.33 to
It is held at 133 Pa (10 to 1000 mTorr).

Then, in this state, from the high frequency power source 41,
A high frequency power having a predetermined frequency (for example, 13.56 MHz) is supplied to the mounting table 2.

By applying high frequency power to the mounting table 2 which is the lower electrode, a high frequency electric field is formed in the processing space between the shower head 15 which is the upper electrode and the mounting table 2 which is the lower electrode. And magnetic field forming mechanism 2
A magnetic field of 0 is formed, and plasma etching is performed in this state.

In this case, as described above, when both ends of the coaxial cable 30 are not connected to the connectors 10a and 40a and electrical continuity is not obtained, or when both ends of the coaxial cable 30 are connected to the connector 10a. , 40a
If the electrical connection is not obtained even if the electrical connection is established, the high-frequency power source 41 will not be turned on, and if the electrical connection is surely obtained. Only the high frequency power supply 41 is turned on and the processing is executed.

Then, when the predetermined etching process is executed, the etching process is stopped by stopping the supply of the high-frequency power from the high-frequency power source 11, and the semiconductor wafer W is processed in the reverse order of the above-mentioned procedure. It is carried out of the vacuum chamber 1.

In the above embodiment, the present invention is
Although the example applied to the etching apparatus of the type that supplies high frequency power only to the lower electrode has been described, the present invention is not limited to such a case and, for example, supplies high frequency power to both the upper electrode and the lower electrode. The present invention can be applied to any type of plasma processing apparatus such as a type etching apparatus and a plasma processing apparatus for forming a film.

[0056]

As described above, according to the present invention,
The electrical connection state between the high-frequency power supply unit and the processing unit can be detected reliably and easily, and the safety can be further improved as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a main part of a plasma processing apparatus according to another embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a main part of a plasma processing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

W ... Semiconductor wafer, 1 ... Vacuum chamber, 2 ... Mounting table (lower electrode), 9 ... Power supply line, 10 ... Matching box, 10a ... Connector, 11 ... Matching device, 15 ...
... Shower head (upper electrode), 30 ... Coaxial cable, 40 ... High frequency power supply unit, 40a ... Connector,
41: high frequency power supply, 42: interlock mechanism (I
/ L), 100 ... Signal supply mechanism, 200 ... Signal detection mechanism.

Claims (9)

[Claims] 1. A processing unit having a vacuum chamber for processing plasma by acting plasma on an object to be processed, a high frequency power supply for supplying high frequency power for generating plasma, the high frequency power supply and the processing. And a connection cable for electrically connecting high frequency power from the high frequency power source to the processing section, and a connection detection signal separable from the high frequency power to the connection cable from one end of the connection cable. Signal supply means, a signal detection means for detecting the connection detection signal from the other end of the connection cable, and a control for controlling the supply of high-frequency power from the high-frequency power source based on the detection result by the signal detection means. And a plasma processing apparatus. 2. The plasma processing apparatus according to claim 1, wherein the signal supply unit is configured to supply a DC signal as the connection detection signal. 3. The plasma processing apparatus according to claim 2, wherein the signal detecting means includes a separating means for separating the high frequency power from the DC signal from the signal supplying means. Plasma processing equipment. 4. The plasma processing apparatus according to claim 3, wherein the signal detection unit detects a voltage value of a DC signal from the signal supply unit to detect a connection state of the connection cable. Plasma processing equipment. 5. The plasma processing apparatus according to claim 1, wherein the signal supply unit is provided on the processing unit side and the signal detection unit is provided on the high frequency power supply side. Characteristic plasma processing device. 6. The plasma processing apparatus according to claim 1, wherein a matching unit is provided in the processing unit, and the connection cable is connected to the matching unit. apparatus. 7. The plasma processing apparatus according to claim 6, wherein the signal detecting means is provided in a box provided with the matching unit. 8. The plasma processing apparatus according to claim 1, wherein the processing unit is arranged in a room having a higher degree of cleanliness than a room in which the high frequency power source is arranged. Plasma processing equipment. 9. The plasma processing apparatus according to claim 1, wherein a cover for covering the connection portion is detachably provided at a connection portion between the connection cable and the high-frequency power source and the processing unit. The plasma processing apparatus is configured to supply the high frequency power from the high frequency power source only when the sensor detects that the cover is attached.