JP4704445B2 - Mounting method of matching box in plasma processing apparatus - Google Patents

Description

  The present invention relates to a method for attaching a matching box in a plasma processing apparatus.

In a manufacturing process of a semiconductor substrate or the like, a plasma processing apparatus that performs surface treatment on these substrates using plasma may be used. As a plasma processing apparatus, for example, an apparatus that performs a chemical vapor deposition (CVD) process is known. Among the plasma processing apparatuses, a parallel plate type plasma processing apparatus is widely used because it is excellent in processing uniformity and has a relatively simple apparatus configuration.
In such a plasma processing apparatus, an electrode for supplying high-frequency power to turn a raw material gas or the like into plasma is provided in a vacuum vessel in which surface treatment of the substrate is performed.

  In addition, in order to electrically connect the power supply rod connected to the electrode and an external electric circuit, the contact arranged in the matching box may be fitted to the power supply rod. In this case, conventionally, as shown in FIG. 8, for example, a contact 70 a for coupling the matching box 70 and the power feeding rod 71 is projected from the beginning of the matching box 70. At the time of attachment, the contactor 70a is fitted into the fitting hole 71a provided in the power supply rod 71, and then the matching box 70 main body is fixed by screwing to a frame or the like provided on the outer wall of the vacuum vessel.

  The impedance matching unit and the matching box containing the impedance matching unit are often attached to or detached from the main body of the plasma processing apparatus for maintenance or correction of electrical characteristics.

  Here, when the contact protruding from the matching box is fitted and connected to the power supply rod, the contact must be fitted before the screwing of the matching box. Since the matching box generally has a considerable weight of about 10 kg to 20 kg, it is difficult to accurately insert the contactor into the power supply rod. Furthermore, unless the heavy matching box is properly supported until the matching box is screwed, strong pressure is applied to the power supply rod. For this reason, there has been a problem that the contactor connecting the matching box and the power feed rod and the power feed rod itself are easily broken.

  This invention is made in view of the said actual condition, and it aims at providing the attachment method of the matching box in the plasma processing apparatus which can attach an electric circuit physically stably.

In order to achieve the above object, a method for attaching a matching box in the plasma processing apparatus according to the present invention is as follows.
A vacuum vessel for processing the substrate using the plasmaized gas;
An electrode for plasma generation disposed in the vacuum vessel;
A high frequency power source for generating high frequency power to be supplied to the plasma generating electrode;
A feeding rod for transmitting high-frequency power generated by the high-frequency power source to the plasma generating electrode;
A matching box having a matching circuit for matching the input impedance to the plasma generating electrode side and the output impedance of the high-frequency power source;
A method for attaching a matching box in a plasma processing apparatus, comprising: a contactor that establishes electrical contact between an output end of high-frequency power in the matching circuit and an input end of high-frequency power in the feeding rod;
In a state where electrical contact between the matching circuit and the power feeding rod is not established, a positioning step for positioning the power feeding rod and the matching box;
A contact establishment step of establishing electrical contact between the matching circuit and the power supply rod by the contactor after the positioning of the power supply rod and the matching box is completed in the positioning step ;
The matching box includes an insertion port into which the contactor can be inserted,
In the contact establishing step, after the matching box is attached to the outer wall of the vacuum vessel in the positioning step, the contactor is inserted into the insertion port, thereby electrically connecting the matching circuit and the power feeding rod. It is characterized by establishing contact .

The plasma processing apparatus includes a heater for heating a substrate to be processed in the vacuum vessel,
The contact establishment step establishes an electrical contact for providing electric power supplied from a commercial power source to the heater by the contactor.

  According to the present invention, the electric circuit can be physically and stably attached.

  Hereinafter, a plasma processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a plasma processing apparatus 1 according to an embodiment of the present invention.
This plasma processing apparatus 1 is configured as a so-called parallel plate type plasma processing apparatus having electrodes that are vertically opposed to each other, and has a function of forming, for example, a SiO ₂ film on the surface of a semiconductor wafer (hereinafter referred to as wafer W). Have

  With reference to FIG. 1, the plasma processing apparatus 1 includes a cylindrical vacuum vessel 2. The vacuum vessel 2 is made of a conductive material such as aluminum that has been anodized (anodized). The vacuum vessel 2 is grounded.

  An exhaust pipe 3 is connected to the bottom of the vacuum vessel 2, and the exhaust pipe 3 is connected to a pump 4. The pump 4 is an exhaust device composed of a turbo molecular pump (TMP) or the like, and can exhaust until the inside of the vacuum vessel 2 reaches a predetermined pressure.

  A susceptor 8 for mounting the wafer W is provided in the lower center of the vacuum vessel 2. FIG. 2 is a diagram illustrating an example of the configuration of the susceptor 8 and the like provided in the lower part of the vacuum vessel 2. The susceptor 8 is made of, for example, aluminum nitride (AlN) formed in a columnar shape, and the electrostatic chuck 10 is placed and fixed on the upper surface, and functions as a lower electrode for generating plasma in the processing space in the vacuum vessel 2. To do.

  The electrostatic chuck 10 is configured by interposing an electrically conductive sheet 10a such as a copper foil plate between two upper and lower insulating layers made of, for example, a polyimide film, and adsorbs and fixes the wafer W by Coulomb force.

  In the susceptor 8, a heater 11 for heating the wafer W to a predetermined temperature is provided. A cooling jacket 12 for circulating the refrigerant is provided between the heater 11 and a heat transfer plate 15. An introduction pipe 13 and a discharge pipe 14 are connected to the cooling jacket 12, and the refrigerant supplied from the introduction pipe 13 is discharged from the discharge pipe 14 through the cooling jacket 12. The bottom surface of the susceptor 8 is supported by a ground member 2 a that is a part of the inner wall of the vacuum vessel 2.

  For example, internal conductor rods 16, 17 a, 17 b and an external conductor tube 18 are connected to the susceptor 8. Thus, the susceptor 8 functions as a lower electrode for receiving high frequency power generated by the first high frequency power supply 50 and drawing plasma into the wafer W in the vacuum vessel 2.

  The inner conductor rod 16 is connected to the conductive sheet 10 a included in the electrostatic chuck 10, and transmits high frequency power generated by the first high frequency power supply 50 and direct current power generated by the DC power supply 52. The internal conductor rods 17 a and 17 b are connected to the heater 11 and transmit commercial frequency power supplied from the commercial power supply 53.

  As shown in FIG. 1, a matching box 20 including a matching circuit unit 21 is disposed between the susceptor 8 and the first high-frequency power source 50, the DC power source 52, and the commercial power source 53. The power feeding rod 19 is drawn out to the outer side wall of the vacuum vessel 2, and the periphery thereof is configured so that the matching box 20 can be attached.

  FIG. 3A is a front view showing an example of the configuration of the matching box 20. As shown in the figure, the matching box 20 includes a matching circuit unit 21 and a contactor insertion unit 22, and a direct current inserted through a filter circuit 55 including a first high-frequency power source 50 and an LPF (Low Pass Filter). It is connected to a power source 52, a commercial power source 53 and the like.

  The matching circuit unit 21 is for matching the output impedance on the first high frequency power supply 50 side with the input impedance on the susceptor 8 side, which is the lower electrode. In addition, the matching circuit unit 21 superimposes the plasma drawing voltage received from the first high frequency power supply 50 on the DC voltage received from the DC power supply 52 via the filter circuit 55 and outputs the superimposed voltage.

  The contactor insertion part 22 is an insertion port of the contactor 23 in which the internal wiring is modularized, and at the innermost part thereof, there is a power supply rod drawing part 24 as an opening through which the power supply bar 19 can be drawn from the back side. Is provided. Further, in the contactor insertion portion 22, an electrode 25 that establishes electrical coupling with the power feeding rod 19 by contacting with an extraction terminal of each wiring stored in the contactor 23 is disposed at a predetermined position. .

  More specifically, the electrode 25 includes, for example, a first electrode 25a connected to the inner conductor rod 16 by insertion of the contactor 23, a second electrode 25b connected to the outer conductor tube 18, and inner conductor rods 17a and 17b. And the third and fourth electrodes 25c and 25d connected to. The first and second electrodes 25a and 25b are connected to the matching circuit unit 21 and function as an output terminal of the matching circuit unit 21. The electrostatic chuck 10 applies a voltage for plasma attraction that is transmitted while being superimposed on a DC voltage. Can be supplied. However, the second electrode 25b connected to the outer conductor tube 18 is grounded. The third and fourth electrodes 25 c and 25 d are connected to a commercial power source 53 and can supply commercial frequency power to the heater 11. A filter circuit made of LPF or the like may be provided between the commercial power supply 53 and the high frequency power to prevent it from wrapping around.

  FIG. 3B is a diagram illustrating an example of the wiring 30 that is arranged inside the contactor 23 and connects the power feeding rod 19 and the electrode 25. In the contactor 23 shown in FIG. 3B, wirings 30a to 30d are built in as a three-dimensional circuit. The wiring 30a is connected to a lead terminal 31a-1 exposed to contact the internal conductor rod 16, and 31a-2 exposed to contact the first electrode 25a. The wiring 30b is connected to an extraction terminal 31b-1 exposed to contact the outer conductor tube 18 and an extraction terminal 31b-2 exposed to contact the second electrode 25b. The wiring 30c is connected to an extraction terminal 31c-1 exposed to contact the internal conductor rod 17a and an extraction terminal 31c-2 exposed to contact the third electrode 25c. The wiring 30d is connected to an extraction terminal 31d-1 that is exposed to contact the internal conductor rod 17b and an extraction terminal 31d-2 that is exposed to contact the fourth electrode 25d.

A shower head 5 having a large number of gas discharge holes is provided on the ceiling of the vacuum vessel 2 facing the mounting surface of the wafer W on the susceptor 8 shown in FIG. The peripheral edge of the shower head 5 is fixed with a bolt or the like and covered with an insulating member 6 formed in an annular shape. The insulating member 6 is made of, for example, quartz whose surface is treated with an insulating coating having high corrosion resistance, such as alumina (Al ₂ O ₃ ) -based ceramics.

FIG. 4 is a diagram showing an example of the configuration of the upper part of the vacuum vessel 2 in detail. Above the shower head 5, for example, two diffusion plates 7a and 7b are disposed, and plasma generating gas, raw material gas, and the like are supplied from gas pipes 26a and 26b connected to the upper part thereof. As shown in FIG. 1, the gas pipes 26 including the gas pipes 26 a and 26 b are connected to a gas supply source 29 via a valve 27, an MFC (mass flow controller) 28, and the like, for example, SiH ₄ , O _{It is} possible to supply a source gas such as ₂ or a plasma generating gas such as Ar gas into the vacuum vessel 2 from the shower head 5. Note that a plurality of gas pipes 26, valves 27, MFCs 28, and gas supply sources 29 are provided as appropriate in accordance with the type of gas provided in the vacuum vessel 2, but in order to simplify the explanation, one each is shown in FIG. Show. Further, the number and configuration of the diffusion plates 7a and 7b can be changed as appropriate according to the type of gas supplied from the gas supply source 29 and the like.

  In addition, a power feeding rod 32 is coupled and fixed to the center of the upper surface of the diffusion plate 7b by screwing or the like, and the high frequency power generated by the second high frequency power source 51 is supplied to the shower head 5. The vacuum vessel 2 functions as an upper electrode for generating plasma such as source gas.

  An impedance matching unit 34 is placed above the vacuum vessel 2 via a shield box 33. The impedance matching unit 34 is for matching the output impedance on the second high-frequency power source 51 side with the input impedance on the shower head 5 side that is the upper electrode, and is for fitting and fixing the power feed rod 32. Socket 40 is provided.

  FIG. 5 is a diagram showing in detail a fitting portion between the socket 40 and the power feeding rod 32. The socket 40 includes a fitting hole 41 for fitting and holding the power supply rod 32 at the center of a metal body 40a formed in a cylindrical shape. The inner wall of the fitting hole 41 is provided with a coating layer 42 made of an insulating material such as a fluororesin such as polytetrafluoroethylene [Teflon (registered trademark)]. That is, the power feed rod 32 and the socket 40 are electrically insulated, and are configured to transmit only the AC component power to the power feed rod 32 side by inductive coupling. Further, the socket 40 is grounded via a capacitor C1 for compensating for a reactor component of impedance and for insulating a direct current component, and a power feed rod 32 fitted into the fitting hole 41 is connected via a capacitor C2. Grounded.

The operation of the plasma processing apparatus 1 according to the embodiment of the present invention will be described below.
In order to process the wafer W by the plasma processing apparatus 1, the shield box 33 and the impedance matching unit 34 are placed above the vacuum vessel 2. At this time, the power feeding rod 32 connected to the diffusion plate 7b is fitted into the fitting hole 41 of the socket 40 provided at the output portion of the impedance matching unit 34 with the coating layer 42 interposed.

  Further, the matching box 20 is fixed to the outer side wall of the vacuum vessel 2 by screws. As shown in FIG. 6, the matching box 20 is connected to the power supply rod 19 connected to the susceptor 8 by screwing with a screw hole provided in the innermost part of the contactor insertion part 22 or the frame. It is fixed to the outer side wall of the vacuum vessel 2 in a state having a space. At this time, the power feeding rod 19 is exposed in a state where the power feeding rod 19 is pulled out from the power feeding rod drawing portion 24 to the contactor insertion portion 22 and positioned. After the matching box 20 is fixed to the outer wall of the side surface of the vacuum vessel 2, the contactor 23 is inserted into the contactor insertion part 22, whereby an electrical circuit between the external circuit including the matching circuit part 21 and the like and the feeder rod 19 is electrically connected. Contact is established.

  When the mounting of the matching box 20 and the impedance matching unit 34 is completed in this way, the wafer W is loaded from a load lock chamber (not shown) and placed on the susceptor 8. At this time, the wafer W is attracted and held by applying a DC voltage generated by the DC power source 52 to the conductive sheet 10 a of the electrostatic chuck 10. Subsequently, the pump 4 is driven to evacuate the inside of the vacuum vessel 2 to a predetermined degree of vacuum. When a predetermined degree of vacuum is reached, the valve 27 is opened, and a predetermined gas supplied from the gas supply source 29, for example, a plasma generating gas such as Ar gas is guided to the gas pipe 26 while controlling the flow rate by the MFC 28, and the shower head 5 Is supplied into the vacuum vessel 2 and maintained at a predetermined pressure.

Further, the inside of the vacuum vessel 2 is heated by the heater 11, and a predetermined source gas such as SiH ₄ gas or O ₂ gas is supplied from a gas supply source 29. For example, the heater 11 heats the inside of the vacuum container 2 so that the temperature of the wafer W becomes a predetermined process temperature within 400 ° C. to 600 ° C.

  The first and second high-frequency power supplies 50 and 51 are activated to start supplying high-frequency power, and a raw material gas or the like is plasma-decomposed to deposit a laminated film on the wafer W. Here, the first high-frequency power source 50 applies a negative bias voltage to attract ions to the wafer W. The frequency of the first high-frequency power supply 50 is determined based on the vibration frequency of plasma ions in the vacuum vessel 2 and the like, and is set to about 10 MHz, preferably about 2 MHz. The second high-frequency power source 51 generates and outputs high-frequency power having a predetermined frequency, for example, a frequency of 60 MHz within a range of 27 MHz to 100 MHz, for example.

  The power feeding rod 32 and the socket 40 connected to the diffusion plate 7b are arranged so that the directions of magnetic fields formed by the alternating currents flowing through them match each other. For example, it is assumed that an alternating current flows in the socket 40 by the high-frequency power transmitted from the second high-frequency power source 51, and a concentric magnetic field is formed in the circumferential direction of the power feed rod 32. In this case, an induced electromotive force is generated in the power feeding rod 32, and high frequency power is transmitted to the shower head 5 which is the upper electrode.

  In other words, the output portion of the impedance matching unit 34 has an electrical characteristic equivalent to that of the transformer T1 shown in FIG. 7, and the high frequency power supplied from the second high frequency power supply 51 is supplied to the shower head as the upper electrode through the power supply rod 32. 5 can be transmitted. Here, the socket 40 corresponds to the primary winding of the transformer T1, and the power feed rod 32 corresponds to the secondary winding of the transformer T1. Further, the plasma load 60 shown in FIG. 7 includes impedances of the power supply rod 32 and the shower head 5, impedances of plasma generated in the processing space in the vacuum vessel 2, and the like.

  Thus, since the socket 40 and the power supply rod 32 are insulated by the coating layer 42, it is not necessary to consider contact resistance in the first place, and the second high frequency power supply 51 has an electrically stable characteristic. High frequency power can be transmitted.

For example, when SiH ₄ gas and O ₂ gas are supplied as source gases, these gases are ionized in the processing space in the vacuum vessel 2 and a SiO ₂ film is deposited on the wafer W. When deposition of the laminated film is completed, supply of discharge power, introduction of source gas, and heating in the vacuum vessel 2 are stopped, the inside of the vacuum vessel 2 is sufficiently purged and cooled, and then the wafer W is taken out.

  As described above, according to the present invention, when the matching box 20 is attached to the outer side wall of the vacuum vessel 2, the contactor is fixed and positioned with a margin between the power supply rod 19 and the contactor. Electrical contact with an external circuit is established by inserting the contactor 23 into the insertion part 22. As a result, it is possible to reduce the pressure applied to the connecting portion with the power supply rod 19 when the matching box 20 is attached, prevent the power supply rod 19 and the contactor 23 from being destroyed, and physically stabilize the external circuit. Can be attached.

  Further, according to the present invention, in the socket 40 provided at the output portion of the impedance matching device 34, the power feeding rod 32 is fitted into the fitting hole 41 with the coating layer 42 made of an insulator interposed. Thereby, it is not necessary to consider the contact resistance at the fitting portion of the power feed rod 32. On the other hand, since the high frequency power is transmitted to the upper electrode side by inductive coupling, the circuit such as the impedance matching unit 34 is electrically stable. Can be attached.

  The present invention is not limited to the above embodiment, and various modifications and applications are possible. For example, in the above-described embodiment, it has been described that the coating layer 42 is provided in the socket 40 into which the power feeding rod 32 connected to the upper electrode is fitted. However, the present invention is not limited to this. That is, in the power supply rod 19 connected to the susceptor 8 as the lower electrode, a plurality of metal bodies may be coupled using a socket configured in the same manner as the socket 40. In this case, the DC voltage output from the DC power supply 52 is transmitted by electrical contact with the power feed rod 19, and the socket is supplied with high-frequency power generated by the first high-frequency power supply 50. do it.

  The configuration of the contactor 23 can be arbitrarily changed according to the type of power source that supplies power to the susceptor 8 that is the lower electrode, etc., and appropriate electrical contact between the power supply rod 19 and an external circuit is achieved. It is possible to use a lead terminal and an electrode for establishing the wiring and wiring.

The configuration of the plasma processing apparatus 1 can also be arbitrarily changed. For example, the plasma processing apparatus 1 includes a coil or a permanent magnet for generating a predetermined magnetic field around the vacuum vessel 2, and the wafer W is formed using electron cyclotron resonance or the like. It may be processed.
In addition, the present invention is not limited to a plasma processing apparatus that performs plasma CVD processing, but supplies high frequency power to a shower head or susceptor to plasma a target object such as a semiconductor wafer, an LCD substrate, or a solar cell substrate. As long as it is a processing apparatus, it can be applied to an etching apparatus, an ashing apparatus, or the like.

It is a figure which shows an example of a structure of the plasma processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of structures, such as a susceptor provided in the lower part of the vacuum vessel. (A) is a front view which shows an example of a structure of a matching box, (b) is a figure which shows an example of the internal wiring of a contactor. It is a figure which shows an example of a structure of the upper part of a vacuum vessel. It is a figure which shows the fitting part of a socket and an electric power feeding rod in detail. It is a figure for demonstrating the operation | movement which attaches a matching box. It is a figure which shows the equivalent circuit of the path | route which transmits high frequency electric power from a 2nd high frequency power supply to a shower head. It is a figure for demonstrating the conventional matching box.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 Vacuum vessel 3 Exhaust pipe 4 Pump 5 Shower head 8 Susceptor 10 Electrostatic chuck 11 Heater 19, 32, 71 Feeding rod 20, 70 Matching box 21 Matching circuit part 22 Contactor insertion part 23 Contactor 34 Impedance Matching device 40 Socket 41 Insertion hole 42 Coating layer 50, 51 High frequency power source 52 DC power source 53 Commercial power source C1, C2 Capacity

Claims (2)

A vacuum vessel for processing the substrate using the plasmaized gas;
An electrode for plasma generation disposed in the vacuum vessel;
A high frequency power source for generating high frequency power to be supplied to the plasma generating electrode;
A feeding rod for transmitting high-frequency power generated by the high-frequency power source to the plasma generating electrode;
A matching box having a matching circuit for matching the input impedance to the plasma generating electrode side and the output impedance of the high-frequency power source;
A method for attaching a matching box in a plasma processing apparatus, comprising: a contactor that establishes electrical contact between an output end of high-frequency power in the matching circuit and an input end of high-frequency power in the feeding rod;
In a state where electrical contact between the matching circuit and the power feeding rod is not established, a positioning step for positioning the power feeding rod and the matching box;
A contact establishment step of establishing electrical contact between the matching circuit and the power supply rod by the contactor after the positioning of the power supply rod and the matching box is completed in the positioning step ;
The matching box includes an insertion port into which the contactor can be inserted,
In the contact establishing step, after the matching box is attached to the outer wall of the vacuum vessel in the positioning step, the contactor is inserted into the insertion port, thereby electrically connecting the matching circuit and the power feeding rod. Establish contact,
A method for attaching a matching box in a plasma processing apparatus. The plasma processing apparatus includes a heater for heating a substrate to be processed in the vacuum vessel,
The contact establishment step establishes an electrical contact for providing electric power supplied from a commercial power source to the heater by the contactor.
The method for attaching a matching box in the plasma processing apparatus according to claim 1 .

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