JPH0819529B2 - Plasma processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a CVD apparatus, and more particularly to a plasma CVD apparatus in which a gas is activated by plasma without increasing damage to an object to be processed by plasma. It relates to a CVD electrode for depositing a quality film at high speed.

[Conventional technology]

As a conventional single-wafer type plasma processing apparatus, there is a capacitively coupled type including parallel plate electrodes. The parallel plate electrodes are 2
With a structure in which one electrode plate is placed in parallel, the object to be processed is placed on one electrode plate, and high frequency power is applied between this electrode and a pair of electrodes to generate plasma, which is used for plasma CVD In this case, the electrode portion facing the object to be processed has a hollow structure, a large number of small holes are opened toward the object to be processed, and the CVD reaction gas is flowed from the small holes toward the object to be processed through the hollow portion. , Is activated by plasma to deposit a film on the object to be processed. (For example, "Basics of Plasma and Film Formation" by Mitsuharu Onuma, Nikkan Kogyo Shimbun, p158 Sho 61) However, the processing speed of the parallel plate type is about 200 nm / min (during SiO ₂ film formation) It took about 5 minutes to form a film of about 1 μm, and it was desired to improve the processing speed.

In the apparatus described above, if the high frequency power applied to the parallel plate in order to improve the processing speed is increased, the processing speed is increased, but damage to the object to be processed occurs,
There is a problem that the film quality deteriorates.

This is because the self-excitation potential is increased by the application of high power, and high-energy ions collide with the object to be processed, and the ease with which they are excited depends on the gas species and the balance of the activated gas concentration is lost. it is conceivable that. An invention that solves this problem is Japanese Patent Laid-Open No. 57-26441, and the apparatus according to the invention has a pre-excitation chamber capable of generating plasma in addition to the reaction chamber. In the pre-excitation chamber, only the gas that is difficult to activate is flowed to pre-excite it and introduce it into the reaction chamber along with the gas that is easy to activate. Since it is not necessary to apply a large amount of power to the electrodes of the above, damage to the workpiece can be prevented, and the composition ratio of the deposited film can be controlled by adjusting the power applied to the preliminary generation chamber and the reaction chamber. However, in this method, the gas that is difficult to activate is excited by high-frequency discharge, so that the activation of the gas is insufficient.

As means for increasing the activation concentration of gas, there is disclosed in
As described in Japanese Patent No. 57-167631, there is a method in which a reactive gas is pre-excited by microwave plasma. Microwave (typically 2.45GHz) instead of high frequency (typically 13.56MHz)
, The plasma density will increase by 1 to 2 digits (
10 ¹¹ / cm ³ ), the rate at which the reaction gas collides with the electrons in the plasma and is excited increases, and the concentration of the activated gas increases.

[Problems to be solved by the invention]

In the above conventional device, the distance between the activation chamber and the reaction chamber is long,
Further, since the introduction ports are also biased, it is difficult to uniformly introduce the pre-excited activated gas onto the object to be processed without lowering the concentration, and a high-quality film can be obtained on the substrate to be processed. However, it is difficult to perform processing at high speed and uniformly.

That is, the above-mentioned conventional technology does not consider the point that a high-quality film without plasma damage or the like is generated uniformly and at high speed, and the film quality deteriorates when the processing speed is increased,
Alternatively, there is a problem that the uniformity is deteriorated and the processing speed is reduced when a high quality and uniform film is obtained.

An object of the present invention is to provide a plasma processing apparatus capable of uniformly producing a high-quality film without plasma damage or the like on an object to be processed at high speed.

[Means for solving problems]

The above-mentioned object is to provide an activation chamber means for introducing a first source gas and a first source gas for supplying the first source gas to the activation chamber means.
Of the gas supply means and the activation chamber means to which the first source gas is supplied to supply the first high-frequency power to generate plasma of the first source gas and activate the first source gas. A high-frequency power supply means, a processing chamber means having a mounting table for mounting a substrate therein, and a second processing chamber inside the processing chamber means.
Second gas supply means for supplying the raw material gas, and the first raw material gas, which is activated inside the activation chamber means, between the activation chamber means and the processing chamber means, is loaded inside the processing chamber means. A partition means having a large number of small holes for uniformly supplying the substrate placed on the mounting table and a large number of gas supply holes for uniformly supplying the second source gas on the substrate, and the mounting table. Plasma processing comprising: a second high-frequency power supply means for forming a thin film on the substrate by supplying a second high-frequency power to generate plasma of a second source gas in the vicinity of the substrate. Achieved by the device.

[Action]

The plasma processing apparatus is composed of two chambers, an activation chamber and a reaction chamber having an object to be treated. In the activation chamber, a high-density plasma of 7.4 × 10 ¹⁰ / cm ³ can be generated by microwave discharge, but because of the absence of a magnetic field, microwaves cannot propagate in the plasma and are reflected by the surface. However, it is impossible to increase the plasma density, but by making the microwave introduction member convex, the contact area between the microwave and plasma increases, and the plasma volume increases. Further, by making the dimensions of the activation chamber a resonance condition, it is easy to ignite plasma and generate stable plasma, and it is possible to arbitrarily increase the activation concentration of the gas that is difficult to activate and is introduced into the activation chamber.

The flat plate provided at the boundary between the activation chamber and the reaction chamber makes it possible to evenly supply the active species of the gas that is difficult to activate generated in the activation chamber and the reaction gas that is easily activated to the object to be processed. At this time, it is possible to shorten the distance between the activation chamber and the object to be treated, and to introduce the active species evenly on the object to be treated without substantially reducing the concentration of the active species, the gas is opposed to the object to be treated. An activation chamber is provided on the opposite side of the blower plate and the gas blower plate from the object to be processed.

The gas that is activated in the activation chamber is a gas that is difficult to activate, and the gas that is easily activated is introduced directly into the reaction chamber so as not to go around to the activation chamber, and is supplied by a high-frequency radio wave with low power on the object to be processed. It is activated by the generated plasma. Here, the gas that is easily activated is also introduced into the object to be treated evenly, so that it is introduced through the holes alternately formed with the small holes leading to the activation chamber of the gas blowing plate.

As a result, the activated gas concentration of the gas that is difficult to activate can be increased independently, and it can be uniformly supplied to the object to be processed without lowering the concentration, and the easily activated gas is exposed to high-density plasma by microwave. Since it can be activated only by the low-power plasma on the object to be processed, it is possible to control and optimize the ratio of the concentrations of a plurality of activated gases, and it is possible to perform high-speed film formation without deteriorating the film quality. Further, the gas can be uniformly supplied onto the object to be processed from the gas blowout plate facing the object to be processed.

In the reaction chamber, the easily activated gas introduced from the flat plate is activated by the low-density plasma generated on the object to be treated, and the surface of the object is reacted with the active species from the activation chamber to form a film. Deposit.

As described above, the reactive gas can be independently activated by a plurality of plasmas, and the activated gas can be uniformly and efficiently supplied to the object to be processed, so that a high-quality film can be obtained. Can be formed uniformly and at high speed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows the first embodiment, in which the activation chamber 1 is provided with a microwave introduction window 2 on one side, in which a material that transmits microwaves and holds a vacuum (quartz or alumina porcelain, etc.)
The microwave introducing member 3 is provided, and the introducing member 3 projects into the activation chamber 1. The activation chamber 1 forms an input microwave cavity resonator, and the size of the resonator can be varied by the plunger 4. A plurality of blow-out holes 5 are provided at the other end of the activation chamber, and a first supply port 6 for the reaction gas is provided near the window 2 in the activation chamber 1.

A reaction chamber 7 is attached to the outlet of the blow-out hole 5, a vacuum exhaust port 8 is provided in the lower part of the reaction chamber 7, and an object 9 to be treated is placed on a table 10 in the central portion. . The table 10
Has a heater 11 built therein to allow the temperature to be set arbitrarily, and is provided with a blow-out hole 5 facing the object to be treated 9 which is insulated from the reaction chamber 7 and is connected to the high-frequency power source 12. On the surface, the second supply port for gas is alternated with the outlet hole.
A gas supply hole 14 connected to 13 is provided (see FIG. 2). In addition, the microwave introduction window 2 of the activation chamber 1
On the side, a microwave source 15 having a tuner for matching the activation chamber and the incident microwave and a monitor for measuring the power of the incident microwave and the reflected microwave are provided.
Is installed.

In the above configuration, a gas that is difficult to activate (for example,
If the SiO ₂ film formation, the N ₂ O or O _2, Si ₃ when the N ₄ N ₂ O) a supply port 6, readily gas to activate (e.g., SiO _2, Si ₃ N ₄
In the case of film formation, SiH ₄ gas) is supplied from each gas supply port 14 and vacuum exhaust is performed to a predetermined pressure from the vacuum exhaust port 8. Here, the microwave is oscillated from the microwave oscillating source 15, and the microwave is introduced into the activation chamber 1 through the introduction member 3 by matching the applied microwave with the activation chamber 1 by the plunger 4, and the microwave is determined here. A standing wave is formed, and the reaction gas supplied from the supply port 6 is ionized by this electric field to be in a plasma state. Here, since the microwave enters the activation chamber from the entire surface of the projecting portion of the introducing member 3 and supplies energy to the plasma of the reactive gas, the entire surface of the projecting portion of the introducing member 3 is a high density plasma (plasma density, 7.4 × 10 ¹⁰ / cm ³ ). The reaction gas activated by this plasma is sent to the reaction chamber 7 uniformly through the blowout holes 5 along with the flow of vacuum exhaust. In the reaction chamber 7, together with the activated reactive gas, a gas having a high activation rate is generated by a high frequency on the object to be treated 9 without flowing into the activation chamber from the gas supply port 14. Through the plasma, the heater 11 reacts on the surface of the object 9 to be heated to a predetermined temperature to deposit a film.

As described above, according to this embodiment, the plasma generation area can be increased in the activation chamber, and the microwave absorption area to the plasma can be expanded to efficiently absorb the microwave energy into the plasma. Large-capacity, high-density plasma can be generated, which produces a high-concentration activated reaction gas, which can be uniformly transported over the object to be processed in a short distance while maintaining a high concentration. Since the reaction with the reactive gas activated by the plasma greatly increases, the film can be formed at high speed without deteriorating the film quality.

FIG. 3 shows a second embodiment, in which a microwave introduction port connected to the activation chamber 1 is provided on the upper end surface. This structure has a drawback that it is difficult to obtain a sufficient resonance state because the plunger 4 is not provided, and the reflected power is apt to increase, but it has an advantage that the microwave introduction part becomes simple and the entire electrode becomes small. Regarding the characteristics, the same effects as those of the first embodiment can be obtained. In addition, the gas that is easily activated is not exposed to the microwave plasma, is activated by the plasma generated by the high frequency of low power, and is uniformly supplied onto the object to be processed. Then reacts with the activated gas. Therefore, it is not necessary to apply high power to increase the density of plasma on the object to be processed,
In addition, since the active gas concentration of the gas that is easily activated does not increase, the reaction in the ratio close to the regular stoichiometric ratio increases, and the film formation speed can be increased without deteriorating the film quality. Since the respective gases excited by the .mu.-wave plasma and the high-frequency plasma are evenly supplied toward the object to be processed, the uniformity can be ensured, so that a high quality film can be formed uniformly and at high speed.

As described above, the plasma processing apparatus includes the activation chamber 1
And a reaction chamber 7 having an object 9 to be treated. In the activation chamber 1, a high-density plasma of 7.4 × 10 ¹⁰ / cm ³ can be generated by the discharge of microwaves, but because of the absence of a magnetic field, the microwaves cannot propagate in the plasma at the above-mentioned plasma density. It is impossible to increase the plasma density because it is reflected, but by making the microwave introduction member convex, the contact area between the microwave and plasma increases,
Plasma volume increases. Further, by making the dimensions of the activation chamber 1 a resonance condition, plasma ignition and stable plasma generation are facilitated, and the activation concentration of the gas that is difficult to activate and is introduced into the activation chamber 1 can be arbitrarily increased.

The flat plate provided at the boundary between the activation chamber 1 and the reaction chamber 2 makes it possible to evenly supply the active product of the gas that is difficult to activate generated in the activation chamber and the reaction gas that is easily activated to the object 9 to be processed. There is. At this time, the distance between the activation chamber 1 and the object to be treated 9 can be shortened, the concentration of the active species is hardly reduced, does not decrease into the object 9 to be treated, and is uniformly introduced, so that the object to be treated is A gas blowing plate 14 is provided facing the object 9, and an activation chamber 1 is provided on the side of the gas blowing plate opposite to the object to be treated.

The gas that is activated in the activation chamber 1 is a gas that is difficult to activate, and the gas that is easily activated is introduced directly into the reaction chamber 7 so as not to go around to the activation chamber, and is supplied on the object to be processed 9 with high power and high frequency. Activated by the plasma generated by. Here, in order to evenly introduce the gas that is easily activated into the object 9 to be treated, it is introduced through the holes 14 alternately formed with the small holes 5 communicating with the activation chamber of the gas blowing plate.

As described above, it is possible to independently increase the activation gas concentration of the gas that is difficult to be activated, and to uniformly supply the object 9 to be treated without lowering the concentration, and the gas that is easily activated is exposed to a high density by microwaves. Since it can be activated only by the low-power plasma on the object to be processed, it is possible to control and optimize the ratio of the concentrations of a plurality of activated gases, and it is possible to perform high-speed film formation without deteriorating the film quality. Further, the gas can be supplied uniformly above the gas blowing plate facing the object to be processed 9.

In the reaction chamber 7, the easily activated gas introduced from the flat plate is activated by the low-density plasma generated on the object 9 to be reacted with the active species from the activation chamber on the surface of the object. Deposit the film.

As described above, the reactive gas can be independently activated by a plurality of plasmas, and the activated gas can be uniformly and efficiently supplied to the object to be processed, so that a high-quality film can be obtained. Can be formed uniformly and at high speed.

〔The invention's effect〕

As described above, according to the present invention, a plurality of reaction gases can be independently activated by a plurality of plasmas, so that the reaction in a ratio close to the regular stoichiometric ratio increases and a high quality film is obtained. Can be formed at high speed and uniformly.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention, and FIG. 2 is a partial view of an outlet hole and a gas supply hole in the first embodiment of the present invention as seen from an axial direction. The drawing is a sectional view of a second embodiment of the present invention. 1 ... Activation chamber, 2 ... Window 3 ... Introduction member, 4 ... Plunger 5 ... Blowout hole, 6 ... First supply port 7 ... Reaction chamber, 8 ... Vacuum exhaust port 9 ... Covered Processing object, 10 ... Stand 11 ... Heater, 12 ... High frequency power supply 13 ... Second supply port, 14 ... Gas supply hole 15 ... Microwave source

Front page continued (72) Inventor Kazuhiro Nakajima 2326 Imai, Ome City, Tokyo Inside Device Development Center, Hitachi, Ltd. (56) Reference JP 59-41464 (JP, A) JP 60-117737 (JP) , A)

Claims (4)

[Claims] 1. An activation chamber means for introducing a first raw material gas, a first gas supply means for supplying the first raw material gas to the activation chamber means, and a supply of the first raw material gas. A first high-frequency power is supplied into the activated chamber means to generate plasma of the first raw material gas to activate the first raw material gas.
High frequency power supply means, processing chamber means having a mounting table for mounting a substrate therein, second gas supply means for supplying a second source gas into the processing chamber means, and the activation. Between the chamber means and the processing chamber means, the first source gas activated inside the activation chamber means is evenly distributed inside the processing chamber means on the substrate placed on the mounting table. A partition means having a large number of small holes for supplying and a large number of gas supplying holes for uniformly supplying the second source gas on the substrate, and supplying a second high frequency power to the mounting table. And a second high-frequency power supply means for forming a thin film on the substrate by generating plasma of the second source gas in the vicinity of the substrate. 2. The plasma processing apparatus according to claim 1, wherein the first high-frequency power supply means supplies microwave power, and the first high-frequency discharge is microwave discharge. . 3. The activation chamber means has therein a microwave introduction chamber partitioned by a wall surface through which microwave power can pass, and microwave power is supplied from the microwave power supply means to the microwave introduction chamber. The plasma processing apparatus according to claim 2, wherein the plasma is generated by being introduced into the microwave introduction chamber, transmitted through the wall surface, and supplied to the inside of the microwave introduction chamber. 4. The plasma processing apparatus according to claim 1, wherein the mounting table is installed to face the activation chamber means via the partition wall.