JP2006156695A - Substrate treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment device which prevents generation of plasma damage. <P>SOLUTION: An ALD device has a process tube 31 wherein a processing chamber 32 for carrying out batch treatment of a plurality of wafers 1 is formed, a gas supply tube 38 for supplying dichlorosilane gas 73 to the treatment chamber 32, a gas supply tube 50 for supplying ammonia gas 71 to the treatment chamber 32, an exhaust tube 35 for exhausting the treatment chamber 32, a pair of discharge electrodes 57, 57 for exciting plasma in the treatment chamber 32 and a plasma chamber 48 having an outlet 49 for blowing out active species 72 excited by plasma to the treatment chamber 32. In the ALD device, a detection electrode 65 is disposed in one side of the plasma chamber 48 inside the treatment chamber 32, and a high frequency current detector 66 is connected to the detection electrode 65. Since a high frequency current leaked from the plasma chamber 48 can be detected in an early stage, countermeasures to prevent plasma damage in the wafer 1 of the treatment chamber 32 can be taken. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus, and more particularly to a batch type remote plasma processing apparatus. For example, in a manufacturing method of a semiconductor integrated circuit device (hereinafter referred to as an IC), a semiconductor wafer (hereinafter referred to as a semiconductor integrated circuit including semiconductor elements). , Which is effective for depositing (depositing) an insulating film or a metal film on a wafer.

As a substrate processing apparatus for forming a film on a wafer at a low temperature in an IC manufacturing method, a process tube in which a processing chamber for processing a plurality of wafers at once is formed, a gas supply means for supplying a processing gas into the processing chamber, There has been proposed a batch type remote plasma processing apparatus including an exhaust means for exhausting the processing chamber and a pair of discharge electrodes to which high-frequency power is applied to generate plasma in the processing chamber and excite the processing gas. . For example, see Patent Document 1.
JP 2002-280378 A

  In such a batch type remote plasma processing apparatus, by passing high frequency power generated by an oscillator to a pair of discharge electrodes through a high frequency transformer, a discharge current from the discharge electrode to the processing chamber is interrupted, and parasitic plasma is generated. It is conceivable to prevent this.

  However, in the batch type remote plasma processing apparatus described above, when the insulation property of the high-frequency transformer is lowered, there is a problem that plasma leaks into the processing chamber and causes plasma damage to the wafer. Revealed by the inventor.

  An object of the present invention is to provide a substrate processing apparatus capable of preventing the occurrence of plasma damage.

  A substrate processing apparatus according to the present invention includes a processing chamber for storing and processing a substrate, a gas supply means for supplying a processing gas into the processing chamber, an exhaust means for exhausting the processing chamber, and a plasma in the processing chamber. A pair of electrodes to which high-frequency power is applied to generate the gas and excite the processing gas, and a plasma detection means disposed in the processing chamber to detect a plasma generation state in the processing chamber. Features.

  According to the above means, since the plasma generation state in the processing chamber can be detected, it is possible to take measures to prevent the occurrence of plasma damage.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In this embodiment, a substrate processing apparatus according to the present invention is an atomic layer deposition (hereinafter referred to as ALD) method which is one of plasma CVD methods as an example of plasma processing on a substrate such as a wafer. It is comprised as an ALD apparatus which implements.
In the ALD method, under one film formation condition (temperature, time, etc.), two kinds (or more) of raw material gases used for film formation are sequentially supplied onto the substrate one by one, in units of one atomic layer. In this method, film formation is performed using surface reaction.
For example, in the ALD method in the case of forming a silicon nitride (SiNx) film, dichlorosilane (SiH ₂ Cl ₂ .DCS) gas and ammonia (NH ₃ ) gas are used and high quality at a low temperature of 300 to 600 ° C. Can be formed.
A plurality of types of reactive gases are sequentially supplied one by one. The film thickness can be controlled by the number of reactive gas supply cycles. For example, assuming that the film formation rate is 1 liter / cycle, when a 20 liter film is formed, a plurality of types of gases are supplied for 20 cycles.

As shown in FIG. 1, the ALD apparatus 10 according to the present embodiment includes a casing 11, and a cassette transfer unit 12 is installed on the front surface of the casing 11. The cassette transfer unit 12 includes a cassette stage 13 on which two cassettes 2 serving as carriers of the wafer 1 can be placed. The cassette stage 13 is rotated 90 degrees so that the cassette 2 is in a horizontal posture. It is configured. Below the cassette stage 13, two sets of wafer posture alignment devices 14 are installed.
When the cassette 2 transported by an external transport device (not shown) is placed on the cassette stage 13 in a vertical posture (the wafer 1 stored in the cassette 2 is vertical), the wafer posture alignment is performed. The apparatus 14 aligns the posture of the wafer 1 so that the notches and the orientation flats of the wafer 1 stored in the cassette 2 are the same.

A cassette shelf 15 is provided inside the casing 11 so as to face the cassette delivery unit 12, and a spare cassette shelf 16 is provided above the cassette delivery unit 12.
A cassette transfer device 17 is installed between the cassette transfer unit 12 and the cassette shelf 15. The cassette transfer device 17 includes a robot arm 18 that can move back and forth in the front-rear direction, and the robot arm 18 is configured to be able to traverse and move up and down. The robot arm 18 is configured to transport and transfer the cassette 2 in a horizontal posture on the cassette stage 13 to the cassette shelf 15 or the spare cassette shelf 16 by advancing, retreating, raising and lowering, and traversing.

Behind the cassette shelf 15, a wafer transfer device 19 that can transfer a plurality of wafers 1 at once is installed so as to be able to rotate and move up and down. The wafer transfer device 19 includes a wafer holder 20 that can be moved back and forth. A plurality of wafer holding plates 21 are horizontally attached to the wafer holder 20. The wafer transfer device 19 may be configured to transfer the wafers 1 one by one.
Behind the wafer transfer device 19, a boat elevator 22 for moving up and down a boat 25 holding a plurality of wafers 1 is installed. The boat 25 is placed horizontally on the arm 23 of the boat elevator 22 via a seal cap 24. Is installed.

As shown in FIG. 2, the seal cap 24 is formed in a disk shape having an outer diameter larger than the inner diameter of the furnace port 33 of the process tube 31. The seal cap 24 is configured to close the furnace port 33 of the process tube 31 by contacting the lower end surface of the process tube 31 with the seal ring 24 a interposed therebetween. On the center line of the seal cap 24, a boat 25 is vertically supported through a heat insulating cap portion 26 and supported.
A rotation shaft 27 is inserted on the center line of the seal cap 24, and the rotation shaft 27 moves up and down together with the seal cap 24 and is rotated by a rotation drive device 28. A support plate 29 is horizontally fixed to the upper end of the rotary shaft 27, and the boat 25 is vertically supported on and supported by the support plate 29 via a heat insulating cap portion 26.

The boat 25 includes a pair of end plates 25a and 25b at the top and bottom, and a plurality of (three in this embodiment) holding members 25c that are installed between the both end plates 25a and 25b and arranged vertically. ing. Each holding member 25c is provided with a large number of holding grooves 25d arranged at equal intervals in the longitudinal direction so as to be opened facing each other in the same plane.
Then, by inserting the outer peripheral edges of the wafers 1 between the multiple holding grooves 25d of the holding members 25c, the plurality of wafers 1 are aligned horizontally on the boat 25 with their centers aligned. Are to be held.

As shown in FIGS. 2 to 4, the ALD apparatus 10 includes a process tube 31 that is integrally formed using quartz (SiO ₂ ). The process tube 31 is formed in a cylindrical shape having one end opened and the other end closed. The process tube 31 is vertically arranged so that the center line is vertical and is fixedly supported.
A cylindrical hollow portion of the process tube 31 forms a processing chamber 32 for accommodating and processing a plurality of wafers 1, and a lower end opening of the process tube 31 forms a furnace port 33 for taking in and out the wafer 1. The inner diameter of the process tube 31 is set to be larger than the maximum outer diameter of the wafer 1 to be handled.
A heater unit 34 surrounding the process tube 31 is concentrically provided outside the process tube 31, and the heater unit 34 is configured to heat the processing chamber 32 uniformly or with a predetermined temperature distribution throughout. Yes. The heater unit 34 is installed vertically by being supported by the casing 11 of the ALD apparatus 10.

One end of an exhaust pipe 35 that evacuates the processing chamber 32 is connected to a part of the side wall of the process tube 31 near the furnace port 33. As shown in FIG. 3, the other end of the exhaust pipe 35 is connected to a vacuum pump 36 via a variable flow rate control valve 37.
The variable flow rate control valve 37 is configured to control the pressure in the processing chamber 32 by adjusting the exhaust amount by adjusting the opening of the valve body.

One end of a gas supply pipe 38 is connected to a position on the side wall of the process tube 31 in the vicinity of the furnace port 33 that is approximately 180 degrees opposite to the exhaust pipe 35. As shown in FIG. 3, the other end of the gas supply pipe 38 is connected to a gas supply source 39 that supplies a predetermined gas type in the ALD method. A variable flow rate control valve 40, an upstream side open / close valve 41, a gas reservoir 42, and a downstream side open / close valve 43 are interposed in the middle of the gas supply pipe 38 from the gas supply source 39 side.
In the portion of the process tube 31 facing the gas supply pipe 38, a bowl-shaped partition wall 44 is laid so as to extend in the vertical direction in parallel with the inner peripheral surface of the process tube 31. 45 is formed.
As shown in FIG. 4, a plurality of air outlets 46 are arranged in the partition wall 44 so as to face each other between the wafers 1 adjacent to each other above and below the boat 25. Is set so that the gas supplied to the gas supply chamber 45 is blown out evenly.
When the differential pressure between the gas supply chamber 45 and the processing chamber 32 is small, the opening area of the outlet 46 is preferably set to the same opening pitch with the same opening area from the upstream side to the downstream side. However, when the differential pressure between the gas supply chamber 45 and the processing chamber 32 is large, it is preferable to increase the opening area of the outlet 46 from the upstream side toward the downstream side or to decrease the opening pitch.

A saddle-shaped partition wall (hereinafter referred to as a plasma chamber wall) 47 in which a plasma chamber 48 is formed is located on the side wall of the process tube 31 near the furnace port 33 at a position approximately 90 degrees away from the exhaust pipe 35. It is laid so as to extend in the vertical direction parallel to the inner peripheral surface.
As shown in FIG. 3, the cross-sectional shape of the inward side wall of the plasma chamber wall 47 is formed in an arc shape, and the circumferential width is set to about 60 degrees. At the end of the plasma chamber wall 47 facing the exhaust pipe 35 on the inward side wall, a plurality of air outlets 49 are arranged and opened so as to face each other between the wafers 1 adjacent to each other above and below the boat 25. The air outlets 49 are set so that the gas supplied to the plasma chamber 48 is evenly blown out. The phase difference between the air outlet 49 of the plasma chamber wall 47 and the air outlet 46 of the partition wall 44 forming the gas supply chamber 45 is set to about 120 degrees.
When the differential pressure between the plasma chamber 48 and the processing chamber 32 is small, the opening area of the air outlet 49 of the plasma chamber wall 47 is preferably set to the same opening pitch with the same opening area from the upstream side to the downstream side. . However, when the differential pressure between the plasma chamber 48 and the processing chamber 32 is large, it is preferable to increase the opening area of the air outlet 49 or reduce the opening pitch from the upstream side toward the downstream side.

One end of the gas supply pipe 50 is connected to a position on the side wall of the process tube 31 near the furnace port 33 on the side opposite to the air outlet 49 of the plasma chamber wall 47, and the other end of the gas supply pipe 50 is connected to the ALD method. Is connected to a gas supply source 51 for supplying a predetermined gas type. In the middle of the gas supply pipe 50, a variable flow rate control valve 52 and an on-off valve 53 are provided in order from the gas supply source 51 side.
In addition, one end of a nozzle 54 is connected to the inner side end of the plasma chamber wall 47 of the gas supply pipe 50, and the nozzle 54 stands vertically. In the nozzle 54, a plurality of gas supply ports 55 are arranged at equal intervals in the vertical direction, and are opened inward in the circumferential direction.

Inside the plasma chamber 48, a pair of protective tubes 56, 56 are arranged symmetrically on opposite sides of the center line of the plasma chamber 48, and are laid so as to extend in the vertical direction. Each protective tube 56 is formed in the shape of an elongated circular pipe using a dielectric material and closed at the upper end. The lower end of each protective tube 56 is appropriately bent and penetrates the side wall of the process tube 31 to the outside. Is sticking out. The inside of the hollow portion of each protective tube 56 is communicated with the outside (atmospheric pressure) of the processing chamber 32.
A pair of discharge electrodes 57 formed in the shape of an elongated rod using a conductive material are concentrically laid in the hollow portions of both the protective tubes 56, 56. A high frequency power supply 58 to be applied is electrically connected via a matching unit 59.
The high frequency power supply 58 and the matching unit 59 are controlled by a controller 60. The controller 60 controls the variable flow rate control valves 37, 40, 52, the on-off valves 41, 43, 53, the heater unit 34, and the like.

  A pair of protective tubes 62 for laying a thermocouple 61 as a cascade thermometer is vertically installed at a position 180 degrees opposite to the plasma chamber wall 47 in the side wall near the furnace port 33 of the process tube 31. Has been. Each thermocouple 61 transmits the temperature measurement result to the controller 60, and the controller 60 controls the heater unit 34 and the like based on the temperature measurement result.

In the present embodiment, as shown in FIG. 3, a high-frequency transformer 63 for preventing the generation of parasitic plasma is interposed between the pair of discharge electrodes 57, 57 and the matching unit 59. It is installed.
A protective tube 64 is laid on one side of the plasma chamber 48 in the processing chamber 32 so as to extend in the vertical direction. The protective tube 64 is formed in the shape of a long and narrow circular pipe using a dielectric and closed at the upper end. The lower end of the protective tube 64 is appropriately bent and penetrates the side wall of the process tube 31 and protrudes to the outside. Has been.
In the hollow portion of the protective tube 64, a detection electrode 65 as a plasma detection means for detecting the plasma generation state in the processing chamber 32 is concentrically laid, and the detection electrode 65 is made of a conductive material and is formed into an elongated rod shape. Is formed. A high frequency current detector 66 for detecting a high frequency current is connected to the outer end of the detection electrode 65. The high-frequency current detector 66 is connected to the controller 60 and transmits the detection result to the controller 60.

  Next, a film forming process in an IC manufacturing method using the ALD apparatus 10 having the above configuration will be described.

First, the overall flow as a substrate processing apparatus will be described.
As shown in FIG. 2, a plurality of wafers 1 as substrates to be processed in the ALD apparatus 10 are loaded (charged) into the boat 25 by the wafer transfer apparatus 19.
The boat 25 loaded with a plurality of wafers 1 is lifted by the boat elevator 22 together with the seal cap 24 and the rotating shaft 27 and is loaded into the processing chamber 32 of the process tube 31 (boat loading).

As shown in FIG. 5, when the boat 25 holding the group of wafers is loaded into the processing chamber 32 and the processing chamber 32 is sealed by the seal cap 24, the processing chamber 32 is connected to the exhaust pipe 35. The vacuum pump 36 evacuates to a predetermined pressure or lower, and the power supplied to the heater unit 34 is increased, whereby the temperature of the processing chamber 32 is increased to a predetermined temperature.
Since the heater unit 34 has a hot-wall structure, the temperature of the processing chamber 32 is maintained uniformly throughout the entire structure. As a result, the temperature distribution of the group of wafers held in the boat 25 is uniform over the entire length. At the same time, the in-plane temperature distribution of each wafer 1 is uniform and the same.

  After the temperature of the processing chamber 32 reaches a preset value and stabilizes, a film forming operation by the ALD method described later is performed.

When the predetermined film forming operation is completed, the seal cap 24 is lowered by the boat elevator 22 to open the furnace port 33, and the group of wafers is held from the furnace port 33 to the processing chamber 32 while being held by the boat 25. Unloading (boat unloading).
The group of wafers carried out of the processing chamber 32 is discharged (lowered) from the boat 25 by the wafer transfer device 19.
Thereafter, the plurality of wafers 1 are batch processed by repeating the above-described operation.

Next, a film forming operation by the ALD method will be described in the case where a silicon nitride film is formed using dichlorosilane gas and ammonia gas.
When a silicon nitride film is formed using dichlorosilane gas and ammonia gas, the following first step, second step, and third step are sequentially performed.

In the first step, ammonia gas that requires plasma excitation and dichlorosilane gas that does not require plasma excitation are caused to flow in parallel.
As shown in FIG. 6, both the open / close valve 53 provided in the gas supply pipe 50 and the variable flow rate control valve 37 provided in the exhaust pipe 35 are opened. Ammonia gas 71 whose flow rate is adjusted by the variable flow rate control valve 52 from the gas supply pipe 50 is ejected from the gas supply port 55 of the nozzle 54 to the plasma chamber 48.
Further, high frequency power is applied between the pair of discharge electrodes 57, 57 from a high frequency power source 58 through a matching unit 59 and a high frequency transformer 63. The ammonia gas 71 ejected into the plasma chamber 48 is excited by plasma and is exhausted from the exhaust pipe 35 while being supplied to the processing chamber 32 as the active species 72.
When the ammonia gas 71 is excited by plasma and supplied to the processing chamber 32 as the active species 72 and exhausted, the pressure of the processing chamber 32 is set to 10 to 100 Pa by appropriately adjusting the variable flow rate control valve 37.
The supply flow rate of the ammonia gas 71 controlled by the variable flow rate control valve 52 is 1000 to 10000 sccm (standard cubic centimeters).
The time for which the wafer 1 is exposed to the active species 72 obtained by plasma-exciting the ammonia gas 71 is 2 to 120 seconds.
The control temperature of the heater unit 34 at this time is set so that the wafer temperature is 300 to 600 ° C. Since the ammonia gas 71 has a high reaction temperature, it does not react at the wafer temperature (300 to 600 ° C.) at this time. Therefore, by supplying the ammonia gas 71 as the active species 72 by plasma excitation, the ammonia gas 71 can be deposited on the wafer even when the temperature of the wafer 1 remains in a low temperature range.

When this ammonia gas 71 is supplied to the processing chamber 32 as the active species 72 by plasma excitation, as shown in FIG. 6, the upstream side open / close valve 41 of the gas supply pipe 38 is opened, By closing the downstream opening / closing valve 43, dichlorosilane gas 73 that does not require plasma excitation is caused to flow to the gas reservoir 42. Thereby, the dichlorosilane gas 73 accumulates in the gas reservoir 42 provided between the upstream side open / close valve 41 and the downstream side open / close valve 43.
At this time, the gas flowing into the processing chamber 32 is an active species 72 obtained by exciting the ammonia gas 71 with plasma, and the dichlorosilane gas 73 does not exist in the processing chamber 32. Therefore, the ammonia gas 71 does not cause a gas phase reaction, and the ammonia gas 71 that has been excited by the plasma to become the active species 72 reacts with the underlying film on the wafer 1.

In the second step, as shown in FIG. 7, the on-off valve 53 of the gas supply pipe 50 is closed and the supply of the ammonia gas 71 is stopped.
On the other hand, the supply of the dichlorosilane gas 73 to the gas reservoir 42 is continued. When a predetermined pressure and a predetermined amount of dichlorosilane gas 73 is accumulated in the gas reservoir 42, the upstream side open / close valve 41 is also closed (see FIG. 3). Thereby, the dichlorosilane gas 73 is confined in the gas reservoir 42. The dichlorosilane gas 73 is stored in the gas reservoir 42 so that the pressure becomes 20000 Pa or more.
In addition, the variable flow rate control valve 40, the on-off valves 41 and 43, the variable flow rate control valve 37, and the like so that the conductance between the gas reservoir 42 and the processing chamber 32 is 1.5 × 10 ⁻³ m ³ / s or more. Is controlled by the controller 60.
Further, when considering the ratio between the volume of the processing chamber 32 and the volume of the required gas reservoir 42, the volume of the gas reservoir 42 is 100 to 300 cc when the volume of the processing chamber 32 is 100 l (liter). The volume ratio of the gas reservoir 42 is preferably 1/1000 to 3/1000 times the volume of the processing chamber 32.
Then, as shown in FIG. 7, the variable flow rate control valve 37 of the exhaust pipe 35 is kept open, and the processing chamber 32 is exhausted to 20 Pa or less by the vacuum pump 36, whereby the remaining ammonia gas 71 is removed. Excluded from the processing chamber 32. At this time, if an inert gas such as nitrogen gas is supplied to the processing chamber 32, the remaining ammonia gas 71 can be more effectively removed from the processing chamber 32.

In the third step, when the exhaust of the processing chamber 32 is finished, as shown in FIG. 8, the variable flow rate control valve 37 of the exhaust pipe 35 is closed to stop the exhaust and the gas supply pipe 38. The downstream on-off valve 43 is opened. Accordingly, the dichlorosilane gas 73 stored in the gas reservoir 42 is supplied to the processing chamber 32 at a stretch. At this time, since the variable flow rate control valve 37 of the exhaust pipe 35 is closed, the pressure in the processing chamber 32 rapidly increases and is increased to about 931 Pa (7 Torr).
The time for supplying the dichlorosilane gas 73 is set to 2 to 4 seconds, and then the time for exposure to the elevated pressure atmosphere is set to 2 to 4 seconds, for a total of 6 seconds. At this time, the temperature of the wafer is 300 to 600 ° C., as in the case of supplying the ammonia gas 71.
By supplying the dichlorosilane gas 73, the ammonia gas 71 and the dichlorosilane gas 73 on the base film of the wafer 1 react with each other to form a silicon nitride film on the wafer 1.
Although illustration is omitted, after the film formation, the downstream on-off valve 43 is closed, the variable flow control valve 37 is opened, the processing chamber 32 is evacuated, and the dichlorosilane gas 73 remaining after contributing to the film formation is removed. Eliminated. If an inert gas such as nitrogen gas is supplied to the processing chamber 32 at this time, the dichlorosilane gas 73 remaining after contributing to film formation can be more effectively removed from the processing chamber 32.
Then, the upstream side open / close valve 41 is opened, and supply of the dichlorosilane gas 73 to the gas reservoir 42 in the first step is started.

  The above first to third steps are defined as one cycle, and a silicon nitride film having a predetermined film thickness is formed on the wafer 1 by repeating this cycle a plurality of times.

By the way, in the ALD method, the source gas is adsorbed on the surface of the base film. The amount of adsorption of the raw material gas is proportional to the pressure of the raw material gas and the exposure time of the raw material gas. Therefore, in order to adsorb a desired amount of source gas in a short time, it is necessary to increase the pressure of the source gas in a short time.
In the present embodiment, since the dichlorosilane gas 73 stored in the gas reservoir 42 is instantaneously supplied to the processing chamber 32 after the variable flow rate control valve 37 is closed, the pressure of the dichlorosilane gas 73 in the processing chamber 32 is increased. Can be rapidly increased, and a desired amount of dichlorosilane gas 73 can be instantaneously adsorbed.

Moreover, in the present embodiment, a special step (time) for storing the dichlorosilane gas 73 in the gas reservoir 42 is not required. This is because dichlorosilane gas 73 is stored in parallel in the gas reservoir 42 while the processing chamber 32 is exhausted while ammonia gas 71 is supplied as active species 72 by plasma excitation.
Further, since the dichlorosilane gas 73 is supplied to the processing chamber 32 after exhausting the inside of the processing chamber 32 and removing the ammonia gas 71, the ammonia gas 71 and the dichlorosilane gas 73 do not react on the way to the wafer 1. That is, the dichlorosilane gas 73 supplied to the processing chamber 32 effectively reacts only with the ammonia gas 71 adsorbed in advance on the wafer 1.

By the way, in the ALD method using the ALD apparatus 10 described above, when the high frequency transformer 63 functions normally, the discharge current from the pair of discharge electrodes 57 and 57 to the outside of the plasma chamber 48 is interrupted. The high frequency current does not leak outside the plasma chamber 48 in the processing chamber 32.
However, when the insulation property of the high-frequency transformer 63 is reduced and the discharge current from the pair of discharge electrodes 57 and 57 to the outside of the plasma chamber 48 cannot be cut off, the high-frequency current is generated in the plasma chamber 48 in the processing chamber 32. The present inventors have revealed that there is a problem that parasitic plasma is generated in the processing chamber 32 due to leakage to the outside. This parasitic plasma causes plasma damage to the wafer 1 in the processing chamber 32, which causes a decrease in the yield of the ALD apparatus 10.

  Therefore, in the ADL apparatus 10 according to the present embodiment, the detection electrode 65 is disposed on one side of the plasma chamber 48 in the processing chamber 32, and the high-frequency current detector 66 is connected to the detection electrode 65. A high frequency current leaking from the plasma chamber 48 is detected at an early stage and measures are taken to prevent the occurrence of plasma damage.

That is, in the ALD method using the ALD apparatus 10 described above, when the high-frequency transformer 63 functions normally, the discharge current from the pair of discharge electrodes 57 and 57 to the outside of the plasma chamber 48 is interrupted. The high-frequency current detected by the high-frequency current detector 66 connected to the detection electrode 65 is not detected.
However, if the insulation property of the high-frequency transformer 63 decreases and the discharge current from the pair of discharge electrodes 57 and 57 to the outside of the plasma chamber 48 cannot be cut off, a current is induced in the detection electrode 65 by the leaked high-frequency current. Therefore, the high frequency current is detected by the high frequency current detector 66 connected to the detection electrode 65.
When a signal that detects a high-frequency current is transmitted from the high-frequency current detector 66, the controller 60 warns the possibility of plasma damage. The operator of the ALD apparatus 10 takes appropriate measures such as maintenance and inspection of the high-frequency transformer 63 according to the alarm.

  According to the embodiment, the following effects can be obtained.

1) A detection electrode 65 is arranged on one side of the plasma chamber 48 in the processing chamber 32, and a high-frequency current detector 66 is connected to the detection electrode 65, so that a high-frequency current leaking from the plasma chamber 48 is detected at an early stage. Therefore, it is possible to avoid the occurrence of plasma damage.

2) By avoiding the occurrence of plasma damage, it is possible to improve the yield of the ALD method by the ALD apparatus, and hence the IC manufacturing method, as well as the quality and reliability of the IC.

3) By forming the detection electrode in the shape of a rod and laying it parallel to the discharge electrode, the leaking high-frequency current can be detected over the entire length of the processing chamber, improving the detection accuracy of the detection electrode, that is, the high-frequency current detector Can be made.

4) By configuring the detection electrode in the same structure as the discharge electrode, an increase in the manufacturing cost of the ALD device can be suppressed.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

In the above embodiment, the case where the silicon nitride film is appropriately and precisely formed at a low temperature by alternately supplying dichlorosilane and ammonia has been described. However, the ALD apparatus uses Ta ₂ O in the capacitance portion of the capacitor. _{5 When} removing carbon intervening in the film, removing foreign matters (molecules or atoms other than the film type) intervening in other film types, forming an ALD film on the wafer, diffusing, heat treatment It can be applied to cases.
For example, in a process of nitriding an oxide film for a gate electrode of a DRAM which is an example of an IC, nitrogen gas, ammonia gas, or nitrogen monoxide (N ₂ O) is supplied to a gas supply pipe, and the processing chamber is set to room temperature to 750 ° C. The surface of the oxide film could be nitrided by heating to.
In addition, when the surface of the silicon wafer before the formation of the silicon germanium (SiGe) film is plasma-treated with active particles of hydrogen (H ₂ ) gas, the natural oxide film can be removed and a desired SiGe film is formed. We were able to.

  Although the ALD apparatus has been described in the above embodiment, the present invention is not limited to this and can be applied to other substrate processing apparatuses such as other CVD apparatuses, oxide film forming apparatuses, diffusion apparatuses, and annealing apparatuses.

  In the above embodiment, the case where the wafer is processed has been described. However, the processing target may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.

1 is a partially omitted perspective view showing an ALD apparatus according to an embodiment of the present invention. It is front sectional drawing which shows the principal part. FIG. 3 is a cross-sectional plan view with a circuit diagram taken along line III-III in FIG. 2. It is side surface sectional drawing which follows the IV-IV line of FIG. It is side surface sectional drawing which shows the film-forming process time. It is a plane sectional view with a circuit diagram showing the first step of the ALD method. It is a plane sectional view with a circuit diagram showing the second step of the ALD method. It is a top sectional view with a circuit diagram showing the 3rd step of ALD method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate to be processed), 2 ... Cassette, 10 ... ALD apparatus (batch type vertical hot wall type remote plasma processing apparatus), 11 ... Housing, 12 ... Cassette transfer unit, 13 ... Cassette stage, 14 ... Wafer posture Alignment device, 15 ... cassette shelf, 16 ... spare cassette shelf, 17 ... cassette transfer device, 18 ... robot arm, 19 ... wafer transfer device, 20 ... wafer holder, 21 ... wafer holding plate, 22 ... boat elevator, DESCRIPTION OF SYMBOLS 23 ... Arm, 24 ... Seal cap, 24a ... Seal ring, 25 ... Boat, 25a, 25b ... End plate, 25c ... Holding member, 25d ... Holding groove, 26 ... Thermal insulation cap part, 27 ... Rotating shaft, 28 ... Rotation drive Apparatus 29 ... Support plate 31 ... Process tube 32 ... Processing chamber 33 ... Furnace port 34 ... Heater unit 35 ... Exhaust pipe, DESCRIPTION OF SYMBOLS 6 ... Vacuum pump, 37 ... Variable flow control valve, 38 ... Gas supply pipe, 39 ... Gas supply source, 40 ... Variable flow control valve, 41 ... Upstream side opening / closing valve, 42 ... Gas reservoir, 43 ... Downstream side opening / closing valve, 44 ... partition wall, 45 ... gas supply chamber, 46 ... outlet, 47 ... partition wall, 48 ... plasma chamber, 49 ... outlet, 50 ... gas supply pipe, 51 ... gas supply source, 52 ... variable flow rate control valve, 53 ... On-off valve, 54 ... Nozzle, 55 ... Gas supply port, 56 ... Protection tube, 57 ... Discharge electrode, 58 ... High frequency power supply, 59 ... Matching device, 60 ... Controller, 61 ... Thermocouple (cascade thermometer), 62 ... Protection Pipe 63, high frequency transformer, 64 protective tube 65 detection electrode (plasma detection means) 66 high frequency current detector (plasma detection means) 71 ammonia gas 72 active species 73 dichlorosilane gas

Claims (1)

  A processing chamber for accommodating and processing a substrate, a gas supply means for supplying a processing gas into the processing chamber, an exhaust means for exhausting the processing chamber, and generating plasma in the processing chamber to excite the processing gas A substrate processing apparatus comprising: a pair of electrodes to which a high-frequency power to be applied is applied; and plasma detection means that is disposed in the processing chamber and detects a plasma generation state in the processing chamber.

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