JPH06333842A - Device and method for microwave plasma treatment - Google Patents

Abstract

PURPOSE:To ease matching even when the guide wavelength varies finely and make possible the generation of high-density and highly isolated plasma and the high-quality and high-speed treatment therefor by providing a means for adjusting guide wavelength for changing the sectional dimension of a waveguide. CONSTITUTION:Microwave is introduced from a microwave leading port 3 into a multi-slot antenna 1. Thus, plasma located adjacent to the antenna 1 is generated by the microwave leaking from a slit hole 2. Then the film formation is carried out until the desired film thickness can be obtained. In the meantime, the reflection intensity of the antenna 1 is monitored by a microwave intensity monitor such as a directional coupler and a movable top board is moved by a top board moving mechanism 6 so that the reflection intensity may become the minimum. Thus, by providing a means for adjusting guide wavelength to change the sectional dimension of a waveguide, the matching can be easily realized even when the guide wavelength varied finely.

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 used for manufacturing semiconductor elements, electronic circuits, etc., and particularly to high-speed processing such as thin film formation having high performance such as good step coverage. The present invention relates to a plasma processing apparatus to perform.

[0002]

2. Description of the Related Art Semiconductor elements and electronic circuits, especially VLSI
The plasma processing apparatus occupies an important position in the manufacturing process. SiN for final protective film and S for interlayer insulating film
A plasma CVD apparatus is used to form a thin film of io _2, etc., a sputtering apparatus is used to form a thin film of Al for wiring, an RIE apparatus is used to etch various thin films, and a plasma ashing apparatus is used to ash photoresist. In addition, application to oxynitriding, cleaning, doping, epitaxial process, etc. is also studied.

In recent years, SiH ₄ has been used as an interlayer insulating SiO ₂ film.
A plasma CVD method using an organic silane such as tetraethoxysilane (TEOS) as a raw material gas, which can form a SiO ₂ film having a better step coverage than that of the above, has been used. A SiO ₂ film is formed.

Most of the plasma processing apparatuses that have been put to practical use use a high frequency of 13.56 MHz or a microwave of 2.45 GHz as an excitation source and bring the generated plasma into contact with the substrate for plasma processing. Since a large number of ions in the plasma are accelerated by the sheath electric field formed on the plasma contact surface and enter the substrate with energy of several tens to 100 eV, damage or compressive stress is likely to occur on the substrate surface or film. Further, when an organic source gas such as TEOS is used, an inappropriate reaction such as C—H bond dissociation occurs, carbon is easily mixed in the film, and surface migration is difficult due to vapor phase decomposition. Since it adheres to the substrate, the step coverage decreases.

In order to solve these problems, an isolated plasma processing apparatus in which the plasma generating chamber and the plasma processing chamber are separated has been studied. In addition, a thin film forming method using a photo-assisted plasma CVD apparatus in which a substrate surface light irradiation means is provided in an isolated plasma processing apparatus is being studied with the aim of further improving the quality (for example, J. Jpn. Appl. Phys. Vol. .
29, No. 12, 1990, pp.L2341).

This method uses H, O, N, F, Cl, B
A first gas containing no element other than r, He, Ne, Ar, Kr, Xe and Rn (O _{2 in} the case of an interlayer SiO ₂ film)
Is excited by plasma generated by high frequency, and H, O, N, F, which are supplied to the space isolated from the active species (such as oxygen radicals) generated by the excitation and the plasma,
Cl, Br, He, Ne, Ar, Kr, Xe and Rn
Reacting with a second gas (organic silane in the case of an interlayer SiO ₂ film) composed of an element other than
The reaction intermediate is attached to the coated substrate placed in the space isolated from the plasma, and visible ultraviolet light absorbed by the attached reaction intermediate is applied to the surface of the substrate to remove impurities and volatile components. This is a method of forming a thin film in which vapor phase decomposition of organosilane is suppressed and adheres to a substrate in a state where surface migration easily occurs, so that it is excellent in step coverage and promotes desorption of volatile components due to photo-surface reaction. Therefore, a good quality thin film can be formed.

As a plasma source for these plasma CVD apparatus and photo-assisted plasma CVD apparatus, 1/2 of the wavelength in the tube is used.
Alternatively, it has been considered to use a microwave waveguide with slots (multi-slot antenna) formed at quarter wavelength intervals, and the plasma density and isolation are improved as compared with the use of other plasma sources, and a high performance thin film Formation and high-speed processing are possible, and particularly good step coverage is realized.

[0008]

However, in the above-mentioned conventional apparatus, when the waveguide is not linear (for example, cylindrical) or the manufacturing dimension is deviated, the wavelength inside the tube is subtly changed and matching is achieved. There were times when it wasn't.

Therefore, the present invention solves the above-mentioned problems of the prior art, and the microwave plasma processing having a plasma source capable of forming a high-density and high-isolation plasma with easy matching even if the in-tube wavelength slightly changes. An object is to provide a device and a processing method using the device.

[0010]

The present invention provides at least the following:
(1) plasma processing chamber, (2) means for evacuating the processing chamber to a vacuum, (3) means for supplying processing gas into the processing chamber, (4) a plurality of inner processing chambers arranged on the outer periphery of the processing chamber A plasma processing apparatus having a plasma generation means having a microwave waveguide having a slit hole formed therein and (5) a means for holding a substrate to be processed is provided with a means for changing the in-tube wavelength of the microwave waveguide. Provided are a microwave plasma processing apparatus and a processing method using the apparatus.

According to the present invention, by providing an in-tube wavelength adjusting means such as changing the dimension of the waveguide cross section, even if the in-tube wavelength is slightly changed, matching is facilitated and high density and high isolation plasma is generated. It also enables high-quality and high-speed processing.

The plasma processing apparatus of the present invention will be described with reference to FIG. FIG. 1 is a diagram of a multi-slot antenna,
1A is a cross-sectional view, and FIG. 1B is a side view taken along line X-X of FIG. 1A. In the figure, 1 is a multi-slot antenna, 2 is a slit hole formed inside the multi-slot antenna 1, 3
Are microwave inlets to the multi-slot antenna 1 and 4
Is a propagation promoting material for promoting the introduction of microwaves into the multi-slot antenna 1 and 5 is the multi-slot antenna 1
Movable top plate for adjusting the in-tube wavelength of the
Is a moving mechanism for moving up and down.

Microwaves are introduced into the multi-slot antenna 1 through the introduction port 3 and leaked from the slit holes 2 to generate plasma inside. The reflection intensity from the multi-slot antenna 1 is monitored by a microwave intensity monitor such as a directional coupler (not shown), and the movable top plate 5 is moved by the top movement mechanism 6 so that the reflection intensity is minimized.

The microwave frequency used in the present invention is
Choose an appropriate value in the range 0.8 to 5 GHz (eg commercial frequency 0.915 or 2.45 GHz).

Other than the above multi-slot antenna, the apparatus of the present invention can be applied to any plasma source whose matching changes depending on the guide wavelength.

As the in-tube wavelength adjusting means of the apparatus of the present invention, any means capable of changing the in-tube wavelength such as a waveguide dimension changing means such as moving a top plate can be applied.

[0017]

EXAMPLE 1 An example in which the present invention is applied to a plasma CVD apparatus will be described with reference to FIG. In the figure, 1 is a multi-slot antenna, 5 is a multi-slot antenna 1
Movable top plate for adjusting the in-tube wavelength of the
A moving mechanism for moving up and down, 7 is a film forming chamber, and 8 is S
a coated substrate such as an i substrate, 9 a support for the coated substrate 8, 10
Is a heater for heating the coated substrate 8, 11 is an exhaust port, 12 is a first gas, 13 is a second gas, 14 is a quartz tube, and 15 is a porous diffusion plate.

First, the substrate 8 is placed on the support 9, and a current is passed through the heater 10 to heat the substrate 8 from room temperature to a desired temperature of several hundreds of degrees Celsius. Next, the first gas 12 introduced through the plasma generation region and the second gas 13 introduced directly in the vicinity of the substrate 8 are caused to flow, and the conductance valve (not shown) provided on the exhaust port 11 side allows 1 mTorr.
Hold at the desired pressure of 0 Torr. Furthermore, by introducing microwaves from the microwave introduction port 3 to the multi-slot antenna 1, the microwave leaked from the slit hole 2 causes localized plasma to be generated in the vicinity of the multi-slot antenna 1 to obtain a desired film thickness. Film formation is performed. During this period, the intensity of reflection from the multi-slot antenna 1 is monitored by a microwave intensity monitor such as a directional coupler (not shown), and the movable top 5 is moved by the top moving mechanism 6 so that the intensity of reflection is minimized. .

Specifically, N ₂ 2 is used as the first gas 12.
00sccm, SiH ₄ 20sc as the second gas 13
cm, supply pressure 0.05 Torr, substrate temperature 300
The film formation was performed under the conditions of the temperature of 500 ° C. and microwave power of 500 W.

As a result, a good quality SiN film having a hydrogen content of 10 atm% and a stress of 2 × 10 ⁹ dyn / cm ² compression was formed with little damage and at a high speed of 70 nm / min.

By changing the gas, SiN, SiO
Insulators such as ₂ , Ta ₂ O ₅ , Al ₂ O ₃ and AlN, aS
i, poly-Si, semiconductor such as GaAs, Al, W
It is possible to form a metal such as.

(Embodiment 2) An embodiment in which the present invention is applied to a surface modification device will be described.

Using the apparatus of FIG. 2, 200 sccm of O ₂ (oxidizing gas) was supplied as the first gas 12, the second gas 13 was not supplied, the pressure was 0.2 Torr, the substrate temperature was 500 ° C., The microwave power was 500 W, the other conditions were the same as in Example 1, and the oxidation was performed in the same operation as in Example 1.

As a result, high-quality S having a breakdown voltage of 11 MV / cm
The iO ₂ film was formed at a high speed of 1.5 nm / min with an interface charge density of 4 × 10 ¹⁰ / cm ² with little damage.

By changing the gas, Si, Al, T
Oxidation and nitriding of i, Zn, Ta and the like, and doping of B, As, P and the like are possible.

(Embodiment 3) An example in which the present invention is applied to a cleaning device will be described.

Using the apparatus of FIG. 2, CF ₄ + H ₂ as the first gas 13 is 50 sccm and 10 sccm, respectively.
Supply, no second gas, pressure 0.02 Tor
r, substrate temperature 300 ° C., microwave power 300 W,
Other conditions were the same as in Example 1, and the same operation as in Example 1 was performed. As a result, the natural oxide film on the Si substrate could be completely removed in 1 minute. By changing the gas, it is possible to clean organic substances and heavy metals.

(Embodiment 4) An example in which the present invention is applied to a photo-assisted plasma CVD apparatus will be described.

In this embodiment, the device shown in FIG. 3 is used. In the figure, 7 is a reaction chamber, 8 is a substrate to be treated (coated substrate) such as a Si substrate, 9 is a support for the coated substrate 8, 10 is a heater for heating the coated substrate 8, 11 is an exhaust port, and 12 is a first , 13 is a second gas, 14 is a quartz tube, 15 is a porous diffusion plate, 16 is a light source, 17 is a reflector, 18 is an integrator, and 19 is a light introduction window.

First, the substrate 8 is placed on the support 9, and the substrate 8 is irradiated with light from the light source 16, and the heater 10 is also provided.
A current is applied to the substrate 8 to heat the substrate 8 from room temperature to a desired temperature of several hundreds of degrees Celsius. Next, the first gas 12 introduced through the plasma generation region and the second gas 13 introduced directly in the vicinity of the substrate 8 are caused to flow, and the conductance valve (not shown) provided on the exhaust port 11 side allows 1 mTorr. 0To
Hold at the desired pressure of rr. Furthermore, by introducing microwaves from the microwave introduction port 3 to the multi-slot antenna 1, the microwave leaked from the slit hole 2 causes localized plasma to be generated in the vicinity of the multi-slot antenna 1 to obtain a desired film thickness. Film formation is performed. During this period, the intensity of reflection from the multi-slot antenna 1 is monitored by a microwave intensity monitor such as a directional coupler (not shown), and the movable top 5 is moved by the top moving mechanism 6 so that the intensity of reflection is minimized. .

Specifically, O is used as the first gas 12.₂To
2 slm, 500 sc of TEOS as the second gas 13
cm, pressure 0.1 Torr, light illuminance 0.6 W /
cm ², Substrate temperature of 300 ℃, microwave power of 1kW
The film was formed according to the conditions.

As a result, a high-quality flat SiO ₂ film having a hydrogen content of 1 atm% or less and a stress of 2 × 10 ⁸ dyn / cm ² was formed at a high speed of 180 nm / min.

By changing the gas, SiN, SiO
Insulators such as ₂ , Ta ₂ O ₅ , Al ₂ O ₃ and AlN, aS
i, poly-Si, semiconductor such as GaAs, Al, W
It is possible to form a metal such as.

[0034]

As described above, by providing the in-tube wavelength adjusting means such as changing the dimension of the waveguide cross section, even if the in-tube wavelength is slightly changed, the matching can be easily obtained, and the high density and high density can be achieved. It is possible to generate isolated plasma, and it is possible to perform high-speed processing such as forming a high-performance thin film having excellent performance such as step coverage.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a multi-slot antenna that is an embodiment of the present invention, in which A is a schematic cross-sectional view thereof, and B is a side view of A on the X-X line.

FIG. 2 is a schematic cross-sectional view of a microwave isolated plasma processing apparatus which is one embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an optically assisted plasma processing apparatus that is an embodiment of the present invention.

[Explanation of symbols]

 1 Multi-slot Antenna 2 Slit Hole 3 Microwave Inlet 4 Microwave Propagation Material 5 Movable Top Plate 6 Movable Top Plate Moving Mechanism 7 Processing Chamber (Reaction Chamber) 8 Target Substrate 9 Support of Target Substrate 10 Heater 11 Exhaust Mouth 12 First gas 13 Second gas 14 Quartz tube 15 Porous diffuser plate 16 Light source 17 Reflector 18 Integrator 19 Light introduction window

Claims (9)

[Claims] 1. At least (1) a plasma processing chamber,
(2) means for evacuating the processing chamber to a vacuum, (3) means for supplying a processing gas into the processing chamber, (4) a plurality of slit holes formed inside the processing chamber and formed inside. A plasma processing apparatus having a plasma generation means having a microwave waveguide, and (5) a means for holding a substrate to be processed, characterized in that it has means for changing the in-tube wavelength of the microwave waveguide. apparatus. 2. A means for changing the in-tube wavelength of a waveguide,
The microwave plasma processing apparatus according to claim 1, which is a means for changing the dimensions of the cross section of the waveguide. 3. A means for changing the in-tube wavelength of a waveguide,
The microwave plasma processing apparatus according to claim 2, wherein the inner wall surface of the waveguide is movable. 4. A means for changing the in-tube wavelength of the waveguide,
The microwave plasma processing apparatus according to claim 1, which is means for changing the oscillation wavelength of the power supply. 5. The microwave plasma processing apparatus according to claim 1, wherein the substrate holding means is installed so as not to contact the plasma high density portion. 6. A microwave plasma processing method using the microwave plasma processing apparatus according to claim 1. Description: 7. The microwave plasma processing method according to claim 6, wherein the substrate holding means is irradiated with light including near-ultraviolet light. 8. H, O, N, F, Cl, Br, He, N
A first gas containing only an element selected from e, Ar, Kr, Xe and Rn is supplied to the plasma generation space,
H, O, N, F, Cl, Br, He, Ne, Ar, K
The microwave plasma processing method according to claim 6 or 7, wherein the second gas containing an element other than r, Xe, and Rn is supplied to the space isolated from the plasma. 9. The microwave plasma processing method according to claim 8, wherein the first gas is O ₂ and the second gas is tetraethoxysilane.