JP2000277495A - Microwave plasma processor and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent formation of a dangling bond to the processed body of a microwave plasma processor, by so specifying its frequency that the existence probability of electrons having energy not smaller than a specific electron-volt value becomes not larger than a specific value in the electron-energy distribution of its ionized reaction gas by the microwave passed through its slot electrode. SOLUTION: A microwave source 10, a reaction-gas feed nozzle 50, and a vacuum pump 60 are connected with a microwave plasma processor 100, and it has an antenna storing member 20, first and second temperature controllers 30, 70, and a processing chamber 40. The microwave source 10 comprises a magnetron, and it can generate microwaves having a frequency of about 100-600 MHz. The microwave frequency is so selected previously that the existence probability of electrons having energy not smaller than 10 eV becomes not larger than one-twentieth in the electron-energy distribution of the plasma generated by the processor 100. The thermal conductivity of a temperature regulating plate 32 becomes high by its contacting with the antenna storing member 20, and the temperatures of a wavelength shortening member 22 and a slot electrode 24 are controlled by the temperature control of the temperature regulating plate 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0002]

[0001] The present invention relates to a microwave plasma processing apparatus and method.

[0003]

2. Description of the Related Art In recent years, as semiconductor products have become higher in density and higher in size, a plasma processing apparatus may be used for processes such as film formation, etching, and ashing in a semiconductor product manufacturing process. In particular, 0.1 to 10 mTo
A microwave plasma apparatus capable of stably supplying plasma even under a reduced pressure of about rr has been proposed.

In a typical microwave plasma apparatus, usually, a microwave of 2.45 GHz passes through a waveguide, a transmission window, and a slot electrode in this order, and receives an object to be processed (for example,
A semiconductor wafer or LCD) is placed and introduced into a processing chamber (process chamber) maintained under a reduced pressure environment. 2.
Microwave sources that generate microwaves having a frequency of 45 GHz are used in microwave ovens and the like, are mass-produced, and are often used because of their low cost. On the other hand, a reaction gas is also introduced into the processing chamber, is converted into plasma by microwaves, and becomes strongly active radicals and ions. The plasma reacts with the object to be processed, and a predetermined process such as CVD or etching is performed on the object.

[0005]

However, 2.45 GH
When, for example, plasma CVD is performed by using a microwave having a frequency of z, a dangling bond or the like is formed on an Si wafer at a boundary surface with a film formed thereon (for example, SiO2 or Si3N4). Lattice defects often occur. A dangling bond refers to an unpaired electron when a covalent bond is broken due to disorder in the periodicity of the lattice structure and an unpaired electron is left.
It was found to be due to microwaves having a frequency of Hz. That is, the electron energy of the plasma provided by the microwave having a frequency of 2.45 GHz is generally distributed as shown in FIG. 1 and has a maximum M around 10 eV. The inventor has discovered that the maximum M is a cause of dangling bonds.

[0006] Microwaves having a frequency of 2.45 GHz also have the problem that they cause standing waves in the processing chamber and hinder generation of a uniform plasma density, thereby hindering uniform plasma processing.

Accordingly, it is a general object of the present invention to provide a new and useful microwave plasma processing apparatus and method for solving such problems.

[0008]

According to one aspect of the present invention, there is provided a microwave plasma processing apparatus comprising: a microwave source for generating a microwave; a slot electrode for guiding the microwave; A gas source, a vacuum pump, and the reaction gas source, which can be connected to the vacuum pump and can store the object to be processed, and the microwave that has passed through the slot electrode converts the reaction gas into plasma to form a reduced pressure environment. A processing chamber capable of performing a predetermined plasma processing on the object under processing, wherein the microwave has an electron energy distribution of 10 eV or more in the electron energy distribution of the plasmatized reaction gas, and the existence probability of electrons is 20 minutes or more. Has a frequency that is less than or equal to 1. The microwave has, for example, a wavelength larger than the diameter of the processing chamber.

According to another aspect of the present invention, there is provided a microwave plasma processing apparatus comprising: a microwave source for generating a microwave; a wavelength shortening member for shortening the wavelength of the microwave when the microwave is introduced; A slot electrode that is connected to a wavelength shortening member and guides the microwaves passing through the wavelength shortening member, and can be connected to a reaction gas source and a vacuum pump that supplies a reaction gas, and can store an object to be processed, The microwave that has passed through the slot electrode converts the reaction gas into plasma, and has a processing chamber that can perform a predetermined plasma process on the object under reduced pressure environment, and the microwave is converted into the plasma. Further, the reaction gas has a frequency such that the probability of the existence of electrons of 10 eV or more in the electron energy distribution of the reaction gas becomes 1/20 or less. The microwave is, for example, 100 MHz to 60 MHz.
It has a frequency of 0 MHz.

In a microwave plasma processing method according to an exemplary embodiment of the present invention, a step of introducing an object to be processed into a processing chamber and a step of detecting the existence probability of electrons of 10 eV or more in the electron energy distribution of the plasma-converted reaction gas. A step of introducing a microwave having a frequency that is not more than 1/20 to the slot electrode, a step of controlling the pressure of the processing chamber, and a step of introducing the reaction gas into the processing chamber to form a plasma. Having. The microwave plasma processing method further includes a step of supplying the microwave having the frequency to a wavelength shortening member operable to shorten the wavelength of the microwave, and introducing the microwave to a slot electrode. The step may be configured to introduce the microwave passed through the wavelength shortening member to the slot electrode.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an exemplary microwave plasma apparatus 100 of the present invention used as a plasma CVD apparatus will be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same members. Conventional microwave refers to a frequency of 1 to 100 GHz,
The microwave of the present invention is not limited to this, and is approximately 50 MHz.
１００100 GHz. Here, FIG. 1 is a schematic block diagram of the microwave plasma device 100. The microwave plasma device 100 of the present embodiment is connected to the microwave source 10, the reaction gas supply nozzle 50, and the vacuum pump 60, and includes the antenna housing member 20, the first temperature control device 30, the processing chamber 40, And a second temperature control device 70.

The microwave source 10 is formed of, for example, a magnetron, and can generate a microwave (for example, 5 kW) having a frequency of, for example, about 100 MHz to 600 MHz. In this embodiment, a microwave frequency is selected in advance such that the electron energy distribution of the generated plasma has an electron existence probability of 10 eV or more that is 1/20 or less. Therefore, the present invention does not use a microwave having a frequency of 2.45 GHz which is generally used. This is because a microwave having a frequency of 2.45 GHz has a maximum M as shown in FIG. 4, and electrons having high energy collide with the semiconductor wafer W to cause lattice defects in the semiconductor wafer W ( For example, an interface state density representing a defect of 5 × 10 10 to 2
x1011). In addition, the dangling bond deteriorates the adhesion of the film formed on the semiconductor wafer W.

As shown in FIG. 5, the present inventor has examined the correlation between the electron energy distribution of plasma caused by microwaves having different frequencies and the occurrence of lattice defects. It has been found that the generation of lattice defects can be suppressed to an allowable range if it is about 1/20. The existence probability of an electron of 10 eV or more is an integrated value of the existence probability of 10 eV or more in the graphs shown in FIGS. The maximum M as shown in FIG. 4 does not necessarily occur in the plasma provided by microwaves of all frequencies. For example, such a maximum does not occur at a frequency of 500 MHz. At a frequency of 13.56 MHz,
Although such a maximum does not occur, it is not preferable because the existence probability of electrons of 10 eV or more exceeds 1/20. The frequency of the microwaves corresponding to about 1/20 of the probability of the existence of electrons of 10 eV or more in the electron energy distribution of plasma includes microwaves having a frequency of about 100 MHz to 600 MHz.

Selecting a microwave in such a frequency range has the additional effect of producing a plasma having a uniform density distribution. That is, a processing chamber 40 described later
For example, when storing an 8-inch or 300-mm semiconductor wafer W, the chamber diameter is set to about 350 to 500 mm. In such a processing chamber 40, a uniform and predetermined density distribution of microwaves is required to generate a uniform and predetermined density plasma. For example, if the overall plasma density decreases, the processing speed of the semiconductor wafer changes. As a result, when the plasma processing is temporally managed, a desired processing (etching depth or film thickness) is formed on the semiconductor wafer W even if the processing is stopped for a predetermined time (for example, two minutes). May not be. Further, if the plasma density is partially concentrated, the processing of the semiconductor wafer W is partially changed.

However, the 2.45 GHz microwave is 12
Since it has a wavelength of 2.5 mm and is shorter than the above-described chamber diameter of 350 to 500 mm, several standing waves are generated in the processing chamber 40. Such standing waves give rise to weakness to the distribution of microwaves introduced into the processing chamber 40, and thus hinder uniform distribution of microwaves. As a result, the plasma density in the processing chamber becomes non-uniform, and the above-described problem occurs.

The microwave having a frequency of, for example, 450 MHz, which can be used in the present embodiment, has a wavelength of 67 cm (670 mm), so that it is larger than the chamber diameter and hardly generates a standing wave. Since no standing wave is generated, the existence of the microwave becomes uniform and uniform processing can be achieved. From this point, the microwave source 10 is
It is preferable to be able to generate a microwave having a wavelength larger than the dimension of. If the processing chamber 40 used has a chamber diameter of about 350 mm, the above-described 100
Microwaves from MHz to 600 MHz satisfy this requirement.

After that, the transmission form of the microwave is converted into a TM, TE or TEM mode by a mode converter (not shown). In FIG. 1, an isolator that absorbs a reflected wave of the generated microwave returning to the magnetron, an EH tuner or a stub tuner for matching with a load side are omitted.

The antenna housing member 20 has a wavelength shortening member 2
2, the slot electrode 24 is configured as a bottom plate of the antenna housing member 20 in contact with the wavelength shortening member 22. The antenna housing member 20 is made of a material having a high thermal conductivity (for example, stainless steel), and is in contact with the temperature control plate 32 as described later. Therefore, the temperature of the antenna housing member 20 is set to substantially the same temperature as the temperature of the temperature control plate 32.

The wavelength shortening member 22 is a dielectric having a predetermined permittivity for shortening the wavelength of the microwave. However, as described later, it is preferable to use a predetermined material having a high thermal conductivity in order to transmit the temperature of the cooling plate 32 to the slot electrode 24. In order to make the density of the plasma introduced into the processing chamber 40 uniform, it is necessary to form many slits 25 in the slot electrode 24 described later. The wavelength shortening member 22 has many slits 2 in the slot electrode 24.
5 has the function of enabling the formation of As the wavelength shortening member 22, a substance having a high dielectric constant, for example, an alumina-based ceramic, SiN, or AlN can be used.

For example, AlN has a relative dielectric constant ｔt of about 9, and a wavelength shortening rate n = 1 / (εt) 1/2 = 0.33. Thereby, the speed of the microwave passing through the wavelength shortening member 22 becomes 0.33 times, and the wavelength also becomes 0.33 times,
The interval between the slits 25 of the slot electrode 24 described later can be shortened, and more slits 25 can be formed. More specifically, the outer peripheral dimension of the slit of the slot electrode 24 is 1.4 of the wavelength of the microwave.
Since a frequency of 5 times or more is appropriate, when a 450 MHz microwave is used, the outer diameter of the slot electrode 24 must be 1.45 × 67 = 97 cm or more unless the wavelength shortening member 22 is used. 97x for
An outer dimension of about 0.33 = 32 cm is sufficient.

The slot electrode 24 is screwed to the wavelength shortening member 22 and has, for example, a diameter of 50 cm and a thickness of 1 m.
m or less. Slot electrode 24
Is slightly outward from the center, as shown in FIG. 2, for example,
Many slits 2 starting from a position several cm away
5 are formed spirally and gradually toward the peripheral edge. In FIG. 2, the slit 25 is swirled twice.
In the present embodiment, a slit group is formed by arranging a pair of slits including a pair of slits 25 </ b> A and 25 </ b> B arranged slightly apart in a substantially T shape as described above. The length L1 of each of the slits 25A and 25B is set within a range from about 1/2 of the guide wavelength λ of the microwave to about 2.5 times the free space wavelength, and the width is set to about 1 mm. The distance L2 between the outer ring and the inner ring is set to substantially the same length as the guide wavelength λ although there is a slight adjustment. That is, the length L1 of the slit is set within a range represented by the following equation.

[0022]

(Equation 1) By forming the slits 25A and 25B in this manner, a uniform microwave distribution can be formed in the processing chamber 40. A few m wide along the periphery of the disk-shaped slot electrode 24 outside the spiral slit.
A microwave power reflection preventing radiation element 26 of about m is formed. Thereby, the antenna efficiency of the slot electrode 24 is increased. The slot electrode 24 of the present embodiment
It is needless to say that the pattern of the slit is merely an example, and an electrode having an arbitrary slit shape (for example, an L shape) can be used as the slot electrode.
For example, slot electrodes 124a to 124d having slits 125a to 125d having various shapes such as concentric circles and radial shapes shown in FIGS. 6 to 9 can be used.

A first temperature control device 30 is connected to the antenna housing member 20. First temperature control device 30
Has a function of controlling the temperature change of the antenna housing member 20 and the components in the vicinity of the antenna housing member 20 by micro heat so that the temperature change is within a predetermined range. As shown in FIG. 3, the first temperature control device 30 includes a temperature control plate 32, a sealing member 34, a temperature sensor 36, and a heater device 38, and a water source 39 such as tap water.
Is supplied with cooling water. For ease of control, the water source 39
Is preferably constant. For the temperature control plate 32, a material such as stainless steel, which has a good thermal conductivity and is easy to process the flow path 33, is selected. The flow path 33 penetrates the rectangular temperature control plate 32 vertically and horizontally, for example.
It can be formed by screwing a sealing member 34 such as a screw into the through hole. Of course, regardless of FIG. 3, each of the temperature control plate 32 and the flow path 33 can have an arbitrary shape. Of course, other types of refrigerants (alcohol, Galden, Freon, etc.) can be used instead of the cooling water.

As the temperature sensor 36, a well-known sensor such as a PTC thermistor and an infrared sensor can be used.
Although a thermocouple can be used for the temperature sensor 36, it is preferable that the thermocouple be configured so as not to be affected by the microwave. The temperature sensor 36 may be connected to the flow path 33 or may not be connected. Alternatively, the temperature sensor 3
6 is an antenna housing member 20, a wavelength shortening member 22, and / or
Alternatively, the temperature of the slot electrode 24 may be measured.

The heater device 38 is composed of, for example, a heater wire wound around a water pipe connected to the flow path 33 of the temperature control plate 32. By controlling the magnitude of the current flowing through the heater wire, the temperature of the water flowing through the flow path 33 of the temperature control plate 32 can be adjusted. Since the temperature control plate 32 has a high thermal conductivity, the temperature of the water flowing through the flow path 33 can be controlled to be substantially the same as the temperature of the water.

The temperature control plate 32 is in contact with the antenna housing member 20, and the antenna housing member 20 and the wavelength shortening member 22 have high thermal conductivity. As a result, the temperature of the wavelength shortening member 22 and the temperature of the slot electrode 24 can be controlled by controlling the temperature of the temperature control plate 32.

The wavelength shortening member 22 and the slot electrode 24 are
If there is no temperature control plate 32 or the like, the power of the microwave source 10
By applying (for example, 5 kW) for a long time, the temperature of the electrode itself increases due to power loss in the wavelength shortening member 22 and the slot electrode 24. As a result, the wavelength shortening member 22 and the slot electrode 24 are thermally expanded and deformed.

For example, in the slot electrode 24, the optimum slit length changes due to thermal expansion, so that the entire plasma density in the processing chamber 40, which will be described later, is reduced or the plasma density is partially concentrated. If the overall plasma density decreases, the processing speed of the semiconductor wafer W changes. As a result, when the plasma processing is temporally managed and the processing is stopped after a predetermined time (for example, 2 minutes) has elapsed and the semiconductor wafer W is taken out of the processing chamber 40, the overall plasma density is reduced. If it decreases, a desired process (etching depth or film thickness) may not be formed on the semiconductor wafer W in some cases. Further, if the plasma density is partially concentrated, the processing of the semiconductor wafer W is partially changed.
If the slot electrode 24 is thus deformed due to a change in temperature, the quality of the plasma processing is reduced.

Further, if the temperature control plate 32 is not provided, the material of the wavelength shortening member 22 and the material of the slot electrode 24 are different, and since both are screwed, the slot electrode 24 warps. It will be understood that the quality of the plasma treatment is also reduced in this case.

On the other hand, if the temperature is constant, the slot electrode 24 does not deform even if it is arranged at a high temperature. Also,
In the plasma CVD apparatus, if water is present in the processing chamber 40 in a liquid or mist state, it will be mixed as an impurity into the film of the semiconductor wafer W, so that it is preferable to raise the temperature as much as possible. A member such as an O-ring for sealing between the processing chamber 40 and a dielectric 28 described later is 80
Considering that it has a heat resistance of about 100 to about 100 ° C.,
The temperature control plate 32 (that is, the slot electrode 24)
The temperature is controlled to be about ± 5 ° C. based on 0 ° C. 70
The set temperature such as ° C. and the allowable temperature range such as ± 5 ° C. can be arbitrarily set depending on required processing, heat resistance of constituent members, and the like.

In this case, the first temperature control device 30 obtains the temperature information of the temperature sensor 36 and adjusts the temperature of the temperature control plate 32 to 7
The current supplied to the heater device 38 is controlled (for example, using a variable resistor or the like) so as to be 0 ° C. ± 5 ° C. The slot electrode 24 is designed to be used at 70 ° C., that is, designed to have an optimum slit length when placed in an atmosphere at 70 ° C. Alternatively, the temperature sensor 3
6 is disposed on the temperature control plate 32, it takes time for heat to propagate from the temperature control plate 32 to the slot electrode 24 or vice versa. May be set.

First, the first temperature control device 30 sets the temperature of the temperature control plate 32 at room temperature to be lower than 70.degree. C., so that the heater device 38 is first driven to set the water temperature to approximately 70.degree. The temperature may be supplied to the temperature control plate 32. Alternatively, it is not necessary to supply water to the temperature control plate 32 until the temperature rise due to the micro heat reaches around 70 ° C. Accordingly, the exemplary temperature control mechanism shown in FIG. 3 may include a mass flow controller that regulates the amount of water from the water source 39 and an on-off valve. Temperature control plate 32
When the temperature exceeds 75 ° C., for example, water of about 15 ° C. is supplied from the water source 39 to start cooling the temperature control plate 32, and then when the temperature sensor 36 indicates 65 ° C. By driving the device 38, the temperature of the temperature control plate 32 becomes 70 ° C. ± 5
Control so that it becomes ° C. The first temperature control device 30 includes:
By using the above-described mass flow controller and the on-off valve, for example, water of about 15 ° C. is supplied from the water source 39 to start cooling the temperature control plate 32, and then the temperature sensor 3
Various control methods such as stopping the supply of water when 6 indicates 70 ° C. can be adopted.

As described above, the first temperature control device 30
By controlling the temperature so that the wavelength shortening member 22 and the slot electrode 24 have a predetermined allowable temperature range centered on a predetermined set temperature, the quality of the processing in the processing chamber 40 can be maintained. For example, the slot electrode 24
When designed to have an optimal slit length when placed in an atmosphere at 0 ° C., simply cooling this to about 15 ° C. may not be meaningful to obtain an optimal processing environment. Will be appreciated.

Further, the first temperature control device 30 controls the temperature of the wavelength shortening member 22 and the temperature of the slot electrode 24 simultaneously by controlling the temperature of the water flowing through the temperature control plate 32. This is because the temperature control plate 32, the antenna housing member 20, and the wavelength shortening member 22 are made of a material having high thermal conductivity. By adopting such a configuration, these three temperature controls can be shared by one device, so that the size and cost of the entire device can be prevented in that a plurality of devices are not required. The temperature control plate 32
Is merely an example of the cooling means, and it goes without saying that other cooling means such as a cooling fan can be adopted.

In the present embodiment, the temperature control plate 32 and the antenna housing member 20 are separate members, but the function of the temperature control plate 32 may be provided to the antenna housing member 20. For example, by forming the flow path 32 on the upper surface and / or the side surface of the antenna housing member 20, the antenna housing member 20 can be directly cooled. If the flow path 32 is formed on the side surface of the antenna housing member 20, the wavelength shortening member 22 and the slot electrode 24 can be cooled at the same time. Alternatively, a temperature control plate may be provided around the slot electrode 24, or a flow path may be formed in the slot electrode 24 itself so as not to hinder the arrangement of the slit 25.

The dielectric 28 is formed between the slot electrode 24 and the processing chamber 4.
0. The slot electrode 24 and the dielectric 28 are surface-bonded firmly and confidentially by, for example, brazing. Alternatively, fired ceramic dielectric 28
On the back side of the copper thin film by means such as screen printing,
A pattern is formed in the shape of the slot electrode 24 including the slit, and the copper foil slot electrode 24
May be formed. The dielectric 28 is made of aluminum nitride (AlN) or the like. When the pressure of the processing chamber 40 in a reduced pressure or vacuum environment is applied to the slot electrode 24, the slot electrode 24 is deformed.
To prevent spattering and copper contamination. If necessary, dielectric 28
May be made of a material having a low thermal conductivity to prevent the slot electrode 24 from being affected by the temperature of the processing chamber 40.

Optionally, the dielectric 28 is made of the wavelength shortening member 2.
As in the case of No. 2, it can be formed of a material having high thermal conductivity (for example, AlN). In this case, the temperature of the slot electrode 24 can be controlled by controlling the temperature of the dielectric 28, and the temperature of the wavelength shortening member 22 can be controlled via the slot electrode 24. In this case, a temperature control plate may be formed around the dielectric 28, or a flow path may be formed inside the dielectric 28 so as not to hinder introduction of the microwave into the processing chamber 40. Note that the above-described temperature control can be arbitrarily combined.

The processing chamber 40 has a side wall and a bottom portion formed of a conductor such as aluminum, and is formed in a cylindrical shape as a whole. The inside of the processing chamber 40 is maintained at a predetermined reduced pressure or a vacuum sealed space by a vacuum pump 60 described later. be able to. Processing room 4
The heating plate 42 and a semiconductor wafer W as an object to be processed are stored in the heating plate 42. In FIG. 1, an electrostatic chuck and a clamp mechanism for fixing the semiconductor wafer W are omitted for convenience.

The heating plate 42 is connected to a second temperature control device 70 for setting the temperature in the processing chamber 40 to a predetermined processing temperature, similarly to the heater device 38. The second temperature control device 70 can control the magnitude of the heating current flowing through the hot plate 42 according to the temperature measured by the temperature sensor 72 that measures the temperature inside the processing chamber 40. For example, when the temperature in the processing chamber 40 falls below a predetermined processing temperature as a result of the temperature control by the first temperature control apparatus 30, the second temperature control apparatus 70 4
It can operate to increase the temperature of zero. As for the temperature of the processing chamber 40, a predetermined processing temperature and a permissible temperature range are set in advance, and the second temperature control device 70 can control the operation of the hot plate 42 based on this. The processing temperature and the allowable temperature range used for the processing chamber 40 may be the same as or different from those used by the first temperature control device 30. Further, the heating plate 42 may be integrated with the table on which the semiconductor wafer W is mounted, or may be a separate member. As the temperature sensor 72, the same as the temperature sensor 36 can be used.

A gas supply nozzle 50 made of quartz pipe for introducing a reaction gas is provided on a side wall of the processing chamber 40.
The nozzle 50 is connected to a reaction gas source 58 through a gas flow path 52 through a mass flow controller 54 and an on-off valve 56.
It is connected to the. For example, when a silicon nitride film is to be deposited, a predetermined mixed gas (that is, N2 and H2 added to one of neon, xenon, argon, helium, radon, and krypton) is used as a reaction gas.
Mixed with NH3 or SiH4 gas.

The vacuum pump 60 can evacuate the processing chamber 40 to a predetermined pressure (for example, 0.1 to several tens mTorr). In FIG. 1, the detailed structure of the exhaust system is also omitted.

Next, the operation of the microwave plasma processing apparatus 100 of the present embodiment configured as described above will be described. First, the semiconductor wafer W is housed in the processing chamber 40 by the transfer arm through a gate valve (not shown) provided on the side wall of the normal processing chamber 40. Thereafter, the lifter pins (not shown) are moved up and down to move the semiconductor wafer W
Is arranged on a predetermined mounting surface.

Next, the inside of the processing chamber 40 is depressurized by the pump 60, and maintained at a predetermined processing pressure, for example, 50 mTorr, and from the nozzle 50, for example, a mixed gas of helium, nitrogen and hydrogen and NH3 is further mixed. The reactant gas source 58 is introduced into the processing chamber 40 while controlling the flow rate through the mass flow controller 54 and the on-off valve 56.

The temperature of the processing chamber 40 is adjusted by the second temperature control device 70 and the hot plate 42 so as to be about 70 ° C. Further, the first temperature control device 30 controls the heater device 38 so that the temperature of the temperature control plate 32 becomes approximately 70 ° C. As a result, the wavelength shortening member 22 is
The temperature of the slot electrode 24 is also maintained at about 70 ° C.
The slot electrode 24 is designed to have an optimum slit length at 70 ° C. Further, the slot electrode 24 is ± 5
It is assumed that a temperature error of about ° C. is within an allowable range in advance.

On the other hand, the frequency 45 from the microwave source 10
The microwave of 0 MHz is introduced into the wavelength shortening member 22 in the antenna housing member 20 through, for example, a rectangular waveguide or a coaxial waveguide (not shown) in, for example, a TEM mode. The microwave that has passed through the wavelength shortening member 22 has its wavelength shortened and enters the slot electrode 24, and is introduced from the slit 25 into the processing chamber 40 via the dielectric 28. Since the wavelength shortening member 22 and the slot electrode 24 are temperature-controlled, there is no deformation due to thermal expansion or the like, and the slot electrode 24 can maintain an optimal slit length. This allows the microwaves to be introduced into the processing chamber 40 uniformly (i.e., without partial concentration) and at the desired overall density (i.e., without loss of density).

If the temperature of the temperature control plate 32 rises above 75 ° C. due to continuous use, the first temperature control device 30 introduces cooling water of about 15 ° C. from the water source 39 to the temperature control plate 32. This is controlled so as to be within 75 ° C. Similarly, the temperature of the temperature control plate 32 becomes 65
C. or less, the first temperature control device 30
By controlling 8, the temperature of the water introduced from the water source 39 to the temperature control plate 32 can be increased to make the temperature of the temperature control plate 32 65 ° C. or more.

On the other hand, if the temperature sensor 72 detects that the temperature of the processing chamber 40 has become lower than the predetermined temperature due to the supercooling by the temperature control plate 32, it is necessary to prevent water from entering the wafer W as an impurity. The second temperature control device 70 can control the temperature of the processing chamber 40 by controlling the hot plate 42.

Thereafter, the microwave is used to convert the reaction gas into plasma to perform a film forming process. The film forming process is performed, for example, for a predetermined period of time, and then the semiconductor wafer W
Is discharged out of the processing chamber 40 from the gate valve (not shown). Since a microwave having a desired density is uniformly supplied to the processing chamber 40 without forming a standing wave, a film having a desired thickness is uniformly formed on the wafer W. Also,
Since the electron energy distribution of the plasma generated by the microwave does not cause crystal defects in the wafer W, a high-quality film forming process can be performed. Further, the temperature of the processing chamber 40 is maintained at a temperature at which moisture and the like do not enter the wafer W, so that a desired film forming quality can be maintained.

Although the preferred embodiment of the present invention has been described above, the present invention can be variously modified and changed within the scope of the invention. For example, since the microwave plasma processing apparatus 100 of the present invention does not prevent the use of electron cyclotron resonance, it may include a ring-shaped coil or the like for generating a predetermined magnetic field. Further, although the microwave plasma processing apparatus 100 of the present embodiment is described as a plasma CVD apparatus, the microwave plasma processing apparatus 100 can also be used for etching or cleaning a semiconductor wafer W. Needless to say. Further, the object to be processed in the present invention is not limited to a semiconductor wafer, but includes an LCD and the like. Further, if the frequency of the microwave of the present invention is such that the existence probability of electrons of 10 eV or more is 1/20 or less, the frequency is 2.4.
Of course, it can be used even at 5 GHz or more.

[0050]

According to the microwave plasma processing apparatus and method according to an exemplary embodiment of the present invention, the microwave used has a probability of existence of electrons of 10 eV or more in the electron energy distribution of the plasma-converted reaction gas. Since it has a frequency that is not more than 1/20, it is possible to prevent dangling bonds from being formed on the object to be processed and to maintain desired processing quality. In addition, the microwave plasma processing apparatus and method according to an exemplary embodiment of the present invention can perform uniform processing on a target object by preventing formation of a standing wave.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating the structure of an exemplary microwave plasma processing apparatus according to the present embodiment.

FIG. 2 is a schematic plan view for explaining a specific configuration example of a slot electrode used in the microwave plasma processing apparatus shown in FIG.

FIG. 3 is a schematic block diagram showing a configuration of a first temperature control device and a temperature control plate used in the microwave plasma processing apparatus shown in FIG.

FIG. 4 is a graph schematically showing an electron energy distribution of plasma generated by a microwave having a frequency of 2.45 GHz.

FIG. 5 is a graph schematically showing an electron energy distribution of plasma generated by a microwave having a frequency of 13.56 MHz to 500 MHz.

FIG. 6 is a schematic plan view showing a modification of the slot electrode shown in FIG.

FIG. 7 is a schematic plan view showing another modification of the slot electrode shown in FIG.

FIG. 8 is a schematic plan view showing still another modification of the slot electrode shown in FIG.

FIG. 9 is a schematic plan view showing still another modified example of the slot electrode shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Microwave source 20 Antenna housing member 22 Wavelength shortening member 24 Slot electrode 25 Slit 28 Dielectric 30 First temperature control device 32 Temperature control plate 36 Temperature sensor 38 Heater device 39 Water source 40 Processing chamber 42 Hot plate 50 Reaction gas supply nozzle 58 Reaction gas source 60 Vacuum pump 70 Second temperature controller 72 Temperature sensor

Continued on front page F-term (reference) 4K030 AA06 AA13 AA17 AA18 BA40 CA04 CA12 FA01 JA17 JA18 KA17 KA41 5F004 AA01 AA06 BA20 BB14 BB22 BD01 5F045 AA09 AC01 AC12 BB01 BB12 BB16 BB17 DP04 EB03 EC05 EH02E03E05E03E05E03E05E05H

Claims (6)

[Claims] 1. A microwave source for generating a microwave, a slot electrode for guiding the microwave, a reaction gas source for supplying a reaction gas, a vacuum pump, and a connectable to the reaction gas source and the vacuum pump. A processing chamber capable of storing the object to be processed, the microwave having passed through the slot electrode turning the reaction gas into plasma, and performing predetermined plasma processing on the object to be processed under a reduced pressure environment; And the microwave has 1 in the electron energy distribution of the plasmatized reaction gas.
A microwave plasma processing apparatus having a frequency such that the existence probability of electrons of 0 eV or more becomes 1/20 or less. 2. A microwave source for generating a microwave, a wavelength shortening member for shortening the wavelength of the microwave when the microwave is introduced, and a microwave source connected to the wavelength shortening member and passing through the wavelength shortening member. A slot electrode for guiding a microwave, a reaction gas source for supplying a reaction gas, and a vacuum pump can be connected to the processing object, and the microwave passing through the slot electrode turns the reaction gas into a plasma. A processing chamber capable of performing a predetermined plasma process on the object under reduced pressure environment, wherein the microwave has an electron energy distribution of 10 eV or more in an electron energy distribution of the plasma-converted reaction gas. Probability is 1/20
A microwave plasma processing apparatus having the following frequency. 3. The microwave plasma processing apparatus according to claim 1, wherein the microwave has a wavelength larger than a diameter of the processing chamber. 4. The microwave has a frequency of 100 MHz to 60 MHz.
3. The microwave plasma processing apparatus according to claim 1, which has a frequency of 0 MHz. 5. A step of introducing an object to be processed into a processing chamber, and a microwave having a frequency such that the electron energy distribution of the plasma-converted reaction gas has an electron probability of 10 eV or more that is 1/20 or less. A microwave plasma processing method, comprising: introducing a reaction gas into a slot electrode; controlling a pressure in the processing chamber; and introducing the reaction gas into the processing chamber to generate plasma. 6. The method according to claim 1, further comprising: supplying the microwave having the frequency to a wavelength shortening member operable to shorten the wavelength of the microwave, wherein the step of introducing the microwave to a slot electrode includes: 6. The microwave plasma processing method according to claim 5, wherein the microwave passing through the wavelength shortening member is introduced into the slot electrode.