JPH09115694A - Plasma treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment device in which plasma can be easily ignited even in a low pressure atmosphere. SOLUTION: A device is provided with spark generating means comprising a first and a second electrodes, an electromagnetic wave generating means such as a mercury lamp to generate a UV-ray, and a radiation generating means such as a radioactive isotope. At the time of igniting plasma, particles in a treatment chamber 102a are thus activated, thereby plasma can be easily excited even in a low pressure atmosphere.

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, and more particularly to a plasma processing apparatus capable of igniting plasma under low pressure conditions such as a high frequency induction plasma processing apparatus and a microwave plasma processing apparatus.

[0002]

2. Description of the Related Art Conventionally, a parallel plate type plasma processing apparatus using a high frequency (RF) has been used as an apparatus for plasma processing an object to be processed such as a semiconductor wafer (hereinafter referred to as "wafer") in a processing chamber. Is widely adopted. Such a parallel plate type plasma processing apparatus, by applying a high frequency to any one electrode or both electrodes, to generate plasma between both electrodes, due to the self-bias potential difference between the plasma and the object to be processed, A plasma flow is caused to flow into the processing surface of the object to be processed, for example, etching processing is performed.

However, in the parallel plate type plasma processing apparatus as described above, it is difficult to carry out the ultrafine processing in the submicron unit, and further in the subhalfmicron unit, which is required in accordance with the ultra-high integration of semiconductor devices. .

That is, in order to carry out such a process by the plasma processing apparatus, a low pressure atmosphere (for example, 1 to
At 50 mTorr), it is important to control high-density plasma with high accuracy, and the plasma must be large in area and highly uniform so as to be compatible with large-diameter wafers.

In response to such technical requirements, many approaches have been taken to establish a new plasma source. For example, European Patent Publication No. 379828 discloses a high frequency induction plasma processing apparatus using a high frequency antenna. In this high-frequency induction plasma processing apparatus, one surface of the processing chamber facing the wafer mounting table is made of an insulating material such as quartz glass, and a high-frequency antenna composed of, for example, a spiral coil is installed on the outer wall surface of the processing chamber. A high-frequency electromagnetic field is formed in the processing chamber by applying high-frequency power, and electrons flowing in the electromagnetic field space are made to collide with neutral particles of the processing gas to ionize the gas and generate plasma.

[0006] Further, a microwave plasma processing apparatus using microwaves is also attracting attention as a plasma source for obtaining high density plasma under low pressure. This microwave plasma processing apparatus introduces the microwave oscillated from the magnetron into the processing chamber through the waveguide,
The microwave electric field and a magnetic field generated by a solenoid coil formed in a direction perpendicular to the electric field synergize to generate cyclotron motion in electrons in the plasma to generate plasma.

[0007]

The high-frequency induction plasma processing apparatus and the microwave plasma processing apparatus as described above are capable of stably obtaining high-density plasma under low pressure. Under the conditions, there is a problem that the collision of electrons is hard to occur and therefore the ignition of plasma is difficult. An ignition method has also been proposed in which the pressure in the processing chamber is temporarily increased when plasma is ignited in order to promote plasma ignition in the plasma processing apparatus, but the plasma becomes unstable and the throughput decreases. Had.

The present invention has been made in view of the above-mentioned problems of the conventional plasma processing apparatus, and it is possible to ignite plasma promptly even under a low pressure condition with a simple structure. To provide a new and improved plasma processing apparatus with a plasma ignition device.

[0009]

In order to solve the above problems, according to a first aspect of the present invention, claims 1 to 8 are provided.
As described above, a plasma processing apparatus configured to excite induction plasma in a processing chamber by applying high-frequency power to a high-frequency antenna and perform processing on an object to be processed in the processing chamber, so-called high-frequency induction plasma. A plasma ignition device applicable to a processing device is provided.

First, according to the first aspect of the present invention, the plasma processing apparatus is provided with a spark electrode in the processing chamber, and a potential is applied to the spark electrode at the time of plasma ignition to spark the spark electrode. Then, this spark enables ignition of plasma easily and quickly even under a low pressure condition.

At this time, if the spark electrode is connected to a lead wire for applying high-frequency power to the high-frequency antenna as in claim 2, the plasma ignition device having a simple structure can be obtained by the following operation. Can be configured. That is,
In the state where plasma is not generated, it is difficult for current to flow through the antenna, and high voltage is applied to both ends of the antenna, so sparks are generated at the spark electrodes connected by the lead wires. As a result, when the plasma is ignited, a current easily flows to the high frequency antenna side, the potential generated at the spark electrode is eliminated, the spark is subsided, and the occurrence of pollution due to the spark is automatically eliminated.

By storing the spark electrode in the recess formed on the inner wall surface of the processing chamber as in claim 3, the possibility that the spark electrode becomes a pollution source can be minimized.

According to a fourth aspect of the present invention, the plasma processing apparatus is provided with a transmission window of the processing chamber, and the transmission window is opened by an electromagnetic wave generating means (for example, a mercury lamp that emits ultraviolet rays) during plasma ignition. An electromagnetic wave (for example, ultraviolet ray) is introduced into the processing chamber via the above. Therefore, the electromagnetic waves promote the ionization of the gas in the processing chamber,
Even under low pressure conditions, plasma ignition can be easily and quickly performed.

According to a fifth aspect of the present invention, the plasma processing apparatus includes, in the processing chamber, a thermoelectron generating means composed of, for example, a filament and an extraction electrode. Therefore, the thermoelectron generation means introduces thermoelectrons into the processing chamber during high frequency induction plasma ignition, collides with the gas in the processing chamber, promotes ionization of the gas, and promotes plasma ionization even under low pressure conditions. Ignition is easy and quick. As described in claim 6, the thermoelectron generating means is accommodated in the recess formed in the inner wall surface of the processing chamber, whereby the possibility that the thermoelectron generating means becomes a pollution source can be minimized.

According to a seventh aspect of the present invention, in the plasma processing apparatus, radiation generating means (for example, potassium (K), rubidium (Rb), cadmium (C) is provided in the processing chamber.
d), a radioisotope such as indium (In). Therefore, by irradiating the gas in the processing chamber with radiation during the high frequency induction plasma ignition, the ionization of the gas is promoted, and the plasma is easily and quickly ignited even under a low pressure condition. At that time, as in claim 8,
By accommodating the radiation generating means in the recess formed on the inner wall surface of the processing chamber, it is possible to minimize the possibility that the radiation generating means becomes a pollution source.

In order to solve the above problems, the second aspect of the present invention
According to the above aspect, as described in claims 9 to 14, the microwave is introduced into the processing chamber to excite plasma, and the object to be processed in the processing chamber is processed. Also provided is a plasma ignition device applicable to a plasma processing device, a so-called microwave plasma processing device.

First, according to claim 9, the plasma processing apparatus is provided with a spark electrode in the processing chamber, and a potential is applied to the spark electrode at the time of plasma ignition to spark the spark electrode. Therefore, this spark makes it possible to easily and quickly ignite plasma even under a low pressure condition. By storing the spark electrode in the recess formed on the inner wall surface of the processing chamber as in the tenth aspect, it is possible to minimize the possibility that the spark electrode becomes a pollution source.

According to the eleventh aspect of the present invention, the plasma processing apparatus is provided with the thermoelectron generating means, which is composed of, for example, a filament and an extraction electrode, in the processing chamber. By the thermoelectron generating means, thermoelectrons are introduced into the processing chamber at the time of microwave plasma ignition, collide with gas in the processing chamber, gas ionization is promoted, and plasma ignition is performed even under a low pressure condition. It's done easily and quickly. It is possible to minimize the possibility that the thermoelectron generating means becomes a pollution source by accommodating the thermoelectron generating means in the recess formed in the inner wall surface of the processing chamber as in the twelfth aspect. The thermoelectron generating means may be housed in a recess formed in the inner wall surface of the processing chamber.

According to a thirteenth aspect, in the plasma processing apparatus, radiation generating means (for example, in the processing chamber) is provided.
Potassium (K), Rubidium (Rb), Cadmium (C
d), radioisotopes such as indium (In))
Is provided. Therefore, at the time of microwave plasma ignition,
By irradiating the gas in the processing chamber with the radiation, the ionization of the gas is promoted, and the plasma is easily and quickly ignited even under a low pressure condition. As described in claim 14, by containing the radiation generating means in the recess formed in the inner wall surface of the processing chamber, the possibility that the radiation generating means becomes a pollution source can be minimized.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments of a plasma processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a high frequency induction type inductively coupled plasma (TCP) etching apparatus 100 according to a first embodiment of the present invention. The plasma etching apparatus 110 has a processing container 102 formed of a conductive material such as aluminum in the shape of a cylinder or a rectangular prism, and a predetermined etching process is formed in the processing container 102. Processing chamber 102a.

The processing container 102 is grounded, and a bottom surface of the processing container 102 is provided with a substantially columnar mounting table 106 for mounting an object to be processed, for example, a semiconductor wafer W, via an insulating plate 104 such as ceramics. It is provided. Further, an insulating material 108 made of, for example, quartz glass or ceramic is provided with a sealing member 1 such as an O-ring on a top plate portion of the processing container 102 substantially opposed to the mounting surface of the mounting table 106 on which the wafer W is mounted.
10 is provided in an airtight manner with the insulating material 108 interposed therebetween.
A high-frequency antenna 112 formed by forming a conductor, for example, a copper plate, aluminum, or stainless steel into a spiral shape, a coil shape, or a loop shape is arranged on the outer wall surface of the. The antenna 112 has only to have a function of exhibiting an antenna action for generating plasma, and may have one turn when the frequency is high.

A high frequency power supply 116 for plasma generation is connected via a matching circuit 114 between both terminals of the high frequency antenna 112, that is, between the terminals 112a and 112b.

The mounting table 106 can be constructed by assembling a plurality of members made of aluminum or the like with bolts or the like, and inside thereof,
Temperature adjusting means such as the cooling means 118 and the heating means 120 are internally provided, and are configured so that the processing surface of the semiconductor wafer W can be adjusted to a desired temperature.

The cooling means 118 is composed of, for example, a cooling jacket and the like, and a refrigerant such as liquid nitrogen can be introduced into the cooling jacket through a refrigerant introducing pipe 122. The cooling means 11
It circulates in 8, while cold heat is generated by nucleate boiling. With this configuration, for example, cold heat of liquid nitrogen at −196 ° C. is transferred from the cooling means 118 to the semiconductor wafer W via the mounting table 106, and the processing surface of the semiconductor wafer W can be cooled to a desired temperature. is there. The nitrogen gas generated by the nucleate boiling of liquid nitrogen is discharged from the refrigerant discharge pipe 120 to the outside of the container.

Further, a heating means 120 is arranged on the mounting table 106. The heating means 120 is constructed by inserting a conductive resistance heating element such as tungsten into an insulating sintered body such as aluminum nitride. The resistance heating element receives desired power from the power source 130 via the filter 128 via the power supply lead 126 to generate heat, heats the temperature of the processing surface of the semiconductor wafer W to a desired temperature, and can perform temperature control. It is configured like this.

Further, on the upper surface of the center of the mounting table 106, a semiconductor wafer W, for example, an electrostatic chuck 132 is a processing object as a chuck portion for holding the processing object.
It is provided with a diameter substantially equal to the diameter of the semiconductor wafer W, preferably slightly smaller than the diameter of the semiconductor wafer W. This electrostatic chuck 132
Are two films 13 made of a polymer insulating material such as a polyimide resin as a surface for mounting and holding the semiconductor wafer W.
A conductive film 132c such as a copper foil is sandwiched between 2a and 132b, and the conductive film 132c is connected to a variable DC voltage source 138 via a filter 136 that cuts high frequency on the way by a voltage supply lead 134. It is connected. Therefore, by applying a high voltage of, for example, 2 kV to the conductive film 132c, the wafer W can be attracted and held by the Coulomb force on the upper surface of the upper film 132a of the electrostatic chuck 132.

An annular focus ring 140 is arranged around the mounting table 106 so as to surround the outer periphery of the semiconductor wafer W on the electrostatic chuck 132. The focus ring 140 is made of an insulating or conductive material that does not attract reactive ions, and acts so that the reactive ions are effectively incident only on the inner semiconductor wafer W.

A feeding rod 142 made of a hollow conductor is connected to the mounting table 106, and the blocking capacitor 14 is connected to the feeding rod 142.
A high-frequency power source 146 is connected via 4 and a high-frequency power of, for example, 2 MHz is applied to the mounting table 106 at the time of processing to generate a bias potential between the plasma and the plasma flow on the processing surface of the object to be processed. It can be effectively attracted.

Further, a processing gas supply port 148 is provided in the central portion of the insulating material 108 arranged on the ceiling of the mounting table 106, and a predetermined processing gas such as CF4 gas is supplied from the gas source 150 to the mass flow controller. It can be introduced into the processing chamber 102a via 152.

An exhaust pipe 154 is connected to the bottom of the processing container 102 so that the atmosphere in the processing container 102 can be exhausted by an exhaust means (not shown) such as a vacuum pump. The atmosphere in the processing chamber 102a can be evacuated to an arbitrary degree of reduced pressure, for example, a low pressure atmosphere of 20 mTorr or less.

Further, a processing object loading / unloading port 155 is provided on a side portion of the processing container 102, and the loading / unloading port 155 is automatically opened / closed by a drive mechanism (not shown).
It communicates with the load lock chamber 158 via 56. Then, in the load lock chamber 158, the transfer mechanism 162 including the transfer arm 160 capable of transferring the semiconductor wafers W as the substrates to be processed one by one into the processing container 102.
Is installed.

When performing plasma processing in the plasma processing apparatus 100 configured as described above, high-frequency power is applied to the high-frequency antenna 112 installed above the processing container 102 through the insulating material 108. As a result, a high-frequency electromagnetic field is formed in the processing chamber 102a, electrons flowing in the electromagnetic field space collide with neutral particles of the processing gas to ionize the gas, and plasma is generated. According to the plasma processing apparatus 100, a high density plasma can be stably obtained under a low pressure.
Under a low pressure condition of Torr or less, collision of electrons or the like is unlikely to occur, and thus plasma ignition is difficult. Therefore,
The plasma processing apparatus 100 shown in FIG. 1 is provided with a plasma ignition device, and like the conventional apparatus, for example, the pressure in the processing chamber is increased at the time of plasma ignition to perform ignition, and then a predetermined processing pressure, for example, 1 mTorr. 50m Tor
The plasma can be ignited even in a low-pressure atmosphere similar to that in the processing process, for example, about 10 mTorr, even if the processing is not performed to reduce the pressure to r.

First, the plasma ignition device 202 according to the first embodiment shown in FIG. 1 is mainly composed of a first electrode 204 and a second electrode 206 attached to a side wall 102b in the processing chamber 102a. These electrodes 204, 206 are
For example, it is preferably covered with an insulating material such as ceramics or quartz except for a portion which is made of tungsten or platinum and which generates a spark sufficient to excite plasma. The first electrode 204 is connected to the node 208 in the lead wire connecting the first terminal 112a of the high frequency antenna 112 and the matching circuit 114, and the second electrode 204 matches the second terminal 112b of the high frequency antenna 112. It is connected to the node 210 in the lead connecting the circuits 114.

As described above, by connecting the plasma ignition device 202 including the first electrode 204 and the second electrode 206 in the power feeding circuit to the high frequency antenna 112, the following operation can be obtained during plasma ignition. it can. That is, since plasma does not exist in the processing chamber 112a at the time when power is supplied to the high frequency antenna 112, it is difficult for a current to flow in the high frequency antenna 112, a high voltage is generated, and the first and second electrodes 204, A spark is generated between 206. Then, this spark causes the processing chamber 1
Molecules and atoms of the processing gas in 12a are activated, and plasma is easily excited even in a low pressure atmosphere. When the plasma is excited in this way, the impedance of the plasma is lowered and a current easily flows through the high-frequency antenna 112, so that the voltage across the antenna drops and stable plasma is obtained, and at the same time, the first and second electrodes 20 are provided.
Sparks between 4,206 are stopped or reduced. Thus, according to the present embodiment, the first and second electrodes 20
A plasma ignition device 202 having a simple structure that effectively operates only during plasma ignition can be obtained by only inserting 4, 206 in a power feeding circuit to the high frequency antenna 112.

FIG. 2 shows the plasma ignition device 2 shown in FIG.
Another form of 02 is shown. In the second embodiment and the following description, components having the same functional configurations as those of the plasma processing apparatus 100 shown in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted. I will do it. This plasma ignition device 20
2a is a first electrode 204a and a second electrode 2a installed in the processing chamber 102a, similar to the plasma ignition device 202 described above.
And 06a. Unlike the first embodiment, the plasma ignition device 202 according to the second embodiment is configured separately from the power supply circuit to the plasma high frequency antenna 112, and further, the spark power supply 220 and the controller 22.
2 is provided. At the time of plasma ignition, the controller 222
Sends a trigger signal to both the high frequency power supply 116 and the spark power supply 220, and the first and second electrodes 204a,
A spark is generated between 206a and a high frequency current is applied to the high frequency antenna 112. Processing chamber 102a
In the inside, the particles are activated by the sparks, and the plasma is easily excited by the high frequency induction, so that the plasma can be easily ignited even in a low pressure atmosphere of 20 mTorr or less, for example. Then, after confirming the ignition of the plasma, the spark power supply 220 is turned off,
You can stop the spark. Of course, depending on the application, sparks may be continuously generated even after plasma ignition.

FIG. 3 shows still another form of the plasma ignition device 202 according to the first form shown in FIG. Plasma ignition device 202b according to the third embodiment
The circuit configuration of is similar to that of the plasma ignition device 202 according to the first embodiment. However, in the case of the present embodiment, the recess 102c is provided in a part of the inner wall 102b of the processing container 102, and the first electrode 204b is formed.
The second electrode 206b is installed in the recess 102c. With such a configuration, it is possible to minimize the influence of contamination that may occur from the first and second electrodes on the processing chamber 102c when the spark is generated. Further, an exhaust hole (not shown) may be provided in the recess 102c so as to sequentially exhaust possible contamination. Note that, also in the embodiments described below, the same configuration can be adopted when the plasma ignition device is arranged in the recess of the processing chamber.

The plasma ignition device 2 shown in FIGS.
20, 220a, 220b, a pair of first and second
Electrodes 204, 206, 204a, 206a, 204b,
Although only 206b is shown, it is needless to say that a plurality of pairs of electrodes can be arranged.

FIG. 4 shows a plasma processing apparatus 100a in which a plasma ignition device 220 according to a fourth embodiment of the present invention is mounted. This plasma ignition device 2
Reference numeral 20 denotes an electromagnetic wave generator 222 that generates electromagnetic waves (for example, a mercury lamp that generates ultraviolet rays), a power source 224 that applies power to the mercury lamp 222, and the ultraviolet lamp 2
The controller 226 controls the on / off of the radio frequency generator 22 and the on / off of the high frequency power supply 116. The electromagnetic wave used in this embodiment penetrates a transparent material such as quartz. Therefore, the transmission window 102d made of quartz or the like is provided on a part of the side wall of the processing container 102, and the plasma ignition device 220
Is installed outside the processing container 102, and the transparent window 102
An electromagnetic wave (indicated by a dotted line in the figure) through the processing chamber 10
It can be introduced in 2a.

According to this structure, at the time of plasma ignition,
The controller 226 sends a trigger signal to both the high frequency power supply 116 and the electromagnetic wave generation power supply 224 to apply a current to the high frequency antenna 112 while introducing the electromagnetic wave into the processing chamber 102c, whereby the particles are activated by the electromagnetic wave. Since a high frequency is introduced into the processing chamber 102a in the state,
For example, even in a low pressure atmosphere of 20 mTorr or less, the high frequency induction plasma can be easily excited. After plasma ignition, the ultraviolet lamp 222 may be turned off to stop the irradiation of electromagnetic waves, or the ultraviolet lamps may be turned on and irradiation of electromagnetic waves may be continued. In the illustrated example, an ultraviolet lamp is illustrated as the electromagnetic wave generation device, but the present invention is not limited to this embodiment, and for example, a microwave generation device or the like can be adopted as the electromagnetic wave generation device.

In the illustrated example, the mercury lamp 222 is provided with a reflector 222a, which collects the generated ultraviolet rays and introduces them into the processing chamber 102c to improve the efficiency of plasma ignition. . Further, a plurality of mercury lamps may be installed to improve the efficiency of plasma ignition. Alternatively, an appropriate optical system may be used to collect the electromagnetic waves at a predetermined point or area in the processing chamber 102a. In the above-described embodiment, the transmission window 102d is provided on the side wall of the processing container 102, but SiO is used as the insulating material 108 arranged on the ceiling of the processing container 102.
When 2 or transparent Al2O3 is used, a mercury lamp may be arranged above the insulating material 108, and electromagnetic waves may be introduced into the processing chamber 102c through the insulating material 108.

FIG. 5 shows a plasma processing apparatus 100b in which a plasma ignition device 230 according to a fifth embodiment of the present invention is mounted. This plasma ignition device 2
Reference numeral 30 denotes a thermoelectron generating means 232 such as a filament installed in the processing chamber 102c, and a thermoelectron generating power supply 234.
And a controller 236 for controlling ON / OFF of the filament and ON / OFF of the high frequency power supply 116. As the material of the filament that constitutes the thermoelectron generating means 232, for example, tungsten can be used.

According to this structure, when plasma is ignited,
The controller 236 sends a trigger signal to both the high-frequency power supply 116 and the thermoelectron generation power supply 234, so that the thermoelectrons (in the figure,
It is shown by a dotted line. ) Is generated in the processing chamber 102c,
By applying a current to the high frequency antenna 112, a high frequency can be introduced into the processing chamber 102a activated by thermoelectrons, so that the high frequency induction plasma can be easily excited even in a low pressure atmosphere of 20 mTorr or less. it can. After plasma ignition, the power supply 234 may be turned off to stop the generation of thermoelectrons, or the thermoelectrons may be continuously generated.

FIG. 6 shows a plasma ignition device 230a according to a sixth embodiment of the present invention. The basic configuration of the plasma ignition device 230a according to the sixth embodiment is similar to that of the plasma ignition device 230 according to the fifth embodiment.
Which is substantially the same as the filament 232a and the power supply 2
34a and a controller 236a. However, the plasma ignition device 230 according to the fifth embodiment is not shown in FIG.
Plasma ignition device 202 according to the third embodiment shown in FIG.
Similar to b, the concave portion 1 provided on the side wall of the processing chamber 102a
No. 02c is housed in the processing chamber 102c to minimize the influence of contamination generated from the filament 232a on the inside of the processing chamber 102c. Further, a counter electrode 238a is installed in the recess 102c so that more thermoelectrons can be extracted from the filament 232a.

FIG. 7 shows a plasma ignition device 240 according to the seventh embodiment of the present invention. This plasma igniter 240 has radioactive isotopes such as potassium (K) and rubidium (Rb) on the inner wall surface of the processing chamber 102a.
A radiation generating means 242 such as cadmium (Cd) or indium (In) is attached. According to this structure, the radiation generation means 242 irradiates the processing chamber 102c with radiation (indicated by a dotted line in the figure), collides with the processing gas particles and activates them, and plasma excitation is promoted. Therefore, plasma can be easily ignited even in a low-pressure atmosphere of 20 mTorr or less. In the illustrated example, the radiation generating means 242 includes radiation isotopes such as potassium (K), rubidium (Rb), and cadmium (C).
Although d) and indium (In) are mentioned, the present invention is not limited to such an example, and various types of radiation generating means can be used to generate radiation in the processing chamber 102a.

FIG. 8 shows a plasma ignition device 240a according to an eighth embodiment of the present invention. The plasma ignition device 240a has substantially the same configuration as the ignition device 240 shown in FIG.
42a is provided on the inner wall surface of the processing chamber 102a. However, the plasma ignition device 24 according to the eighth embodiment
0a, similarly to the third embodiment shown in FIG. 3 and the sixth embodiment shown in FIG. 6, a recess 102c is provided in a part of the side wall of the processing chamber 102a, and the radioisotope is provided in the recess 102c. Radioisotope 242 accommodated by body 242a
It is configured so that a does not easily become a pollution source.

Although the embodiment in which the plasma ignition device according to the present invention is applied to the high frequency induction type inductively coupled plasma etching device has been described above, the present invention is not limited to such a device, and the microwave as described below is used. It can also be applied to a plasma etching apparatus.

FIG. 9 shows a microwave plasma etching apparatus 300 according to the ninth embodiment of the present invention. The etching apparatus 300 has a processing container 302 formed of a conductive material such as aluminum in the shape of a cylinder or a rectangular prism, and a predetermined etching process is formed in the processing container 302. It is performed in the processing chamber 302a.

The processing container 302 is grounded, and the bottom of the processing container 302 is provided with an insulating plate (not shown) made of ceramic or the like through which an object to be processed, for example, a semiconductor wafer W is mounted in a substantially columnar shape. A table 304 is installed. Further, an insulating material 306 made of, for example, quartz glass or ceramic is provided on a top plate portion of the processing container 302, which is substantially opposed to the mounting surface of the mounting table 304 on which the wafer W is mounted, via a sealing member (not shown) such as an O-ring. It is airtight. Then, the microwave introducing portion 308a which forms a part of the hollow substantially cylindrical trapezoidal waveguide 308 so as to cover the upper surface of the insulating material 306.
Is provided. The waveguide 308 extends from the top of the microwave introduction part 308a and is connected via a tuner 310 to a microwave oscillator 312 that generates a microwave of, for example, 2.45 GHz.

The mounting table 304 can be constructed by assembling a plurality of members formed of aluminum or the like with bolts or the like, and inside thereof,
A cooling means 314 such as a cooling jacket capable of circulating a coolant such as liquid nitrogen, a temperature adjusting means such as a heating means 316 composed of a resistance heating element, etc. are internally provided, and a desired processing surface of the semiconductor wafer W is obtained. It is configured so that the temperature can be adjusted.

A feeding rod 318 made of a hollow conductor is connected to the mounting table 304, and a high frequency power source 320 is connected to the feeding rod 318. By applying high-frequency power to the mounting table 304, it is possible to generate a bias potential between the mounting table 304 and the plasma and effectively draw the plasma flow to the processing surface of the object to be processed.

Further, a processing gas supply port 322 is provided above the side wall of the processing container 302, and a predetermined processing gas, for example, CF4 gas is introduced into the processing chamber 302a from a gas source through a mass flow controller (not shown). It is possible to introduce.

An exhaust pipe 324 is connected to the bottom of the processing container 302 so that the atmosphere in the processing container 302 can be exhausted by an exhaust means (not shown) such as a vacuum pump. The atmosphere in the chamber 102a can be evacuated to an arbitrary degree of reduced pressure, for example, a low pressure atmosphere of 20 mTorr or less.

Further, a solenoid coil 326 is installed on the outer peripheral area of the side wall of the processing container 302. The solenoid coil 326 is connected to the processing chamber 3 via the waveguide 308.
This is for generating a magnetic field that is perpendicular to the electric field of the microwave introduced in 02a. Due to the synergistic effect of the electric field of the microwave and the magnetic field of the solenoid coil, the cyclotron motion is generated in the electrons in the plasma, whereby a high density plasma can be obtained even under a low pressure of, for example, 20 mTorr or less. However, hitherto, it has been difficult for electrons and the like to collide with each other under such a low pressure condition, and thus it has been difficult to ignite plasma. Therefore,
The illustrated microwave plasma etching apparatus 300 is provided with a plasma ignition device 330.

The plasma ignition device 330 according to the ninth embodiment of the present invention shown in FIG. 9 includes a first electrode 332 and a second electrode 3 attached to an inner wall 302b in a processing chamber 302a.
34, a spark power supply 336 that supplies a sparking voltage to these electrodes, and a controller 338 that controls the spark power supply 336 and the microwave oscillator 312. These electrodes 332, 334 are
For example, it is preferably covered with an insulating material such as ceramics or quartz except for a portion which is made of tungsten or platinum and which generates a spark sufficient to excite plasma.

At the time of plasma ignition, the controller 338 sends a trigger signal to the spark power source 336 and the microwave oscillator 312 to generate a spark between the first and second electrodes 332 and 334, while generating a spark in the processing chamber 302a. Introduce waves. At that time, the processing chamber 30 is sparked.
Since the particles in 2a are excited, plasma can be easily ignited even in a low pressure atmosphere. After the ignition of the plasma is confirmed, the spark power supply 336 can be turned off to stop the spark generation. Of course, depending on the application, sparks may be continuously generated even after plasma ignition.

In the illustrated embodiment, the processing chamber 3
Although a structure in which a pair of electrodes is arranged on the inner wall surface of 02a is shown,
The present invention is not limited to such an example. For example, a plurality of pairs of electrodes may be arranged, or a recess may be provided on the inner wall surface of the processing chamber 302a,
It is also possible to adopt a configuration in which electrodes are arranged there.

FIG. 10 shows a microwave plasma etching apparatus 300a according to the tenth embodiment of the present invention. This microwave plasma etching device 3
The basic configuration of 00a is substantially the same as the device shown in FIG. However, in the tenth embodiment, the plasma ignition device 340 includes a thermoelectron generating unit 342 such as a filament installed in a recess 302c formed in the inner wall surface of the processing chamber 302a, a counter electrode 344, The thermoelectron generating power supply 346, and a controller 34 for controlling on / off of the filament and on / off of the microwave oscillator 312.
8 and mainly. The thermoelectron generating means 34
As the material of the filament forming the second element, for example, tungsten can be used. In addition, the counter electrode 344
Can be made of, for example, stainless steel.

According to this structure, at the time of plasma ignition,
The controller 348 sends a trigger signal to both the microwave oscillator 312 and the thermoelectron generation power supply 346 to introduce microwaves into the processing chamber 302a while generating thermoelectrons inside the processing chamber 302c. At that time, particles of the processing gas in the processing chamber 302c are activated by thermoelectrons generated from the filament, and microwaves are introduced into the particles, whereby plasma can be easily ignited. After plasma ignition, the power supply 346 may be turned off to stop the generation of thermoelectrons, or may continue to generate thermoelectrons.
In the illustrated example, the filament is illustrated as the dedicated thermoelectron generator, but the present invention is not limited to this embodiment, and for example, an ionization vacuum gauge or the like can be used as the thermoelectron generator. In the illustrated example, the filament is housed in the recess formed in the inner wall surface of the processing chamber 302a, but the filament is housed in the inner wall 30 of the processing chamber 302a.
It can also be placed directly on 2b. The counter electrode is for extracting more thermoelectrons from the filament and may be omitted in some cases.

FIG. 11 shows a microwave plasma etching apparatus 300b according to the eleventh embodiment of the present invention. This microwave plasma etching device 3
The plasma igniter 350 mounted on the No. 00b has a radioactive isotope such as potassium (K) or rubidium (R) in the recess 302c formed in the inner wall surface 302b of the processing chamber 302a.
The radiation generating means 352 such as b), cadmium (Cd), and indium (In) is attached. According to this configuration, the radiation from the radiation generation unit 352 (in the figure,
It is shown by a dotted line. ) Is irradiated into the processing chamber 302c, collides with the processing gas particles and is activated, and plasma excitation is promoted. Therefore, plasma can be easily ignited even in a low-pressure atmosphere of 20 mTorr or less. In the illustrated example, as the radiation generating means 352, potassium (K), rubidium (Rb), cadmium (Cd), and indium (In), which are radiation isotopes, are mentioned, but the present invention is not limited to this example. , Using various radiation generating means,
Radiation can be generated in the processing chamber 301a.

Of course, also in this embodiment, the radiation generating means can be directly attached to the inner wall surface 302b of the processing chamber 302a, or the radiation generating means can be installed at a plurality of locations in the processing chamber 302a.

The plasma processing apparatus according to some preferred embodiments of the present invention has been described above by taking the high-frequency inductively coupled plasma etching apparatus and the microwave plasma etching apparatus as examples. However, the present invention is not limited to this, and can be applied to various plasma etching apparatuses suitable for low pressure processing such as a helicon wave plasma etching apparatus. Furthermore, the present invention is not limited to the etching apparatus, and can be applied to various plasma processing apparatuses such as an ashing apparatus, a film forming apparatus, and a sputtering apparatus.

[0063]

As described above, according to the present invention,
By using a plasma ignition device equipped with a spark electrode, a thermoelectron generation means, an electromagnetic wave generation means, a radiation generation means, etc., gas particles in the processing chamber are activated at the time of plasma ignition, so that a low pressure atmosphere of, for example, 20 mTorr or less is used. However, the plasma can be easily ignited. At that time, by housing the plasma ignition device in the recess formed in the inner wall of the processing chamber, it is possible to prevent the plasma ignition device from becoming a pollution source in the processing chamber.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a high frequency inductively coupled plasma etching apparatus according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged configuration diagram showing an outline of a plasma ignition device according to a second embodiment of the present invention.

FIG. 3 is a partially enlarged configuration diagram showing an outline of a plasma ignition device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a schematic configuration of a high frequency inductively coupled plasma etching apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a schematic configuration of a high frequency inductively coupled plasma etching apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a partially enlarged configuration diagram showing an outline of a plasma ignition device according to a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram showing a schematic configuration of a high frequency inductively coupled plasma etching apparatus according to a seventh embodiment of the present invention.

FIG. 8 is a partially enlarged configuration diagram showing an outline of a plasma ignition device according to an eighth embodiment of the present invention.

FIG. 9 is a configuration diagram showing a schematic configuration of a microwave plasma etching apparatus according to a ninth embodiment of the present invention.

FIG. 10 is a configuration diagram showing a schematic configuration of a microwave plasma etching apparatus according to a tenth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a schematic configuration of a microwave plasma etching apparatus according to an eleventh embodiment of the present invention.

[Explanation of symbols]

 100 plasma processing device 102 processing container 102a processing chamber 102b processing chamber inner wall 102c processing chamber recess 106 mounting table 112 high frequency antenna 114 matching box 116 high frequency power supply 202 plasma ignition device 204 first electrode 206 second electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C23F 4/00 C23F 4/00 D H01L 21/203 H01L 21/203 S 21/205 21/205 21 / 3065 21/302 C

Claims (14)

[Claims] 1. A plasma processing apparatus configured to excite induction plasma in a processing chamber by applying high-frequency power to a high-frequency antenna to process an object to be processed in the processing chamber. A plasma processing apparatus, wherein a spark electrode is provided on the spark electrode, and a potential is applied to the spark electrode at the time of plasma ignition to spark the spark electrode. 2. The plasma processing apparatus according to claim 1, wherein the spark electrode is connected to a lead wire that applies high frequency power to the high frequency antenna. 3. The plasma processing apparatus according to claim 1, wherein the spark electrode is housed in a recess formed in the inner wall surface of the processing chamber. 4. A plasma processing apparatus configured to excite induction plasma in a processing chamber by applying high-frequency power to a high-frequency antenna to process an object to be processed in the processing chamber. The plasma processing apparatus is characterized in that when the plasma is ignited, the electromagnetic wave is introduced from the electromagnetic wave generating means into the processing chamber through the transparent window. 5. A plasma processing apparatus configured to excite induction plasma in a processing chamber by applying high-frequency power to a high-frequency antenna to process an object to be processed in the processing chamber. A plasma processing apparatus, characterized in that a thermoelectron generating means is provided in the. 6. The thermoelectron generating means is housed in a recess formed in an inner wall surface of the processing chamber.
The plasma processing apparatus according to claim 5. 7. A plasma processing apparatus configured to excite induction plasma in a processing chamber by applying high-frequency power to a high-frequency antenna to process an object to be processed in the processing chamber. A plasma processing apparatus, characterized in that radiation generating means is provided in the. 8. The radiation generating means is housed in a recess formed in an inner wall surface of the processing chamber.
The plasma processing apparatus according to claim 7. 9. A plasma processing apparatus configured to introduce a microwave into a processing chamber to excite plasma to process a target object in the processing chamber, wherein a spark electrode is provided in the processing chamber. A plasma processing apparatus, characterized in that a potential is applied to a spark electrode at the time of plasma ignition to cause sparking. 10. The spark electrode is housed in a recess formed in an inner wall surface of the processing chamber.
The plasma processing apparatus according to claim 9. 11. A plasma processing apparatus configured to introduce a microwave into a processing chamber to excite plasma to perform processing on an object to be processed in the processing chamber, wherein a thermoelectron generating means is provided in the processing chamber. A plasma processing apparatus comprising: 12. The plasma processing apparatus according to claim 11, wherein the thermoelectron generating means is housed in a recess formed in the inner wall surface of the processing chamber. 13. A plasma processing apparatus configured to introduce a microwave into a processing chamber to excite plasma to perform processing on an object to be processed in the processing chamber, wherein a radiation generating unit is provided in the processing chamber. A plasma processing apparatus, characterized by being provided. 14. The plasma processing apparatus according to claim 13, wherein the radiation generating means is housed in a recess formed in an inner wall surface of the processing chamber.