JP3400909B2 - Plasma processing method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method and apparatus applied to a CVD apparatus, an etching apparatus or the like for forming a thin film on a substrate or converting physical properties of the substrate surface by high density plasma. Is.

[0002]

2. Description of the Related Art CVD with a conventional high density plasma source
As a device, for example, one described in Japanese Patent Laid-Open No. 7-58012 is known.

In FIG. 5, which shows a schematic structure of a conventional CVD apparatus having a high-density plasma source, 21 is a reaction chamber, the upper surface of which is composed of a dielectric plate 22 made of a dielectric material such as quartz, and induction is provided thereon. The coil 23 is installed. For the induction coil 23, for example, 13.56M from the high frequency power source 24.
It is configured to apply high frequency power of Hz.

A lower electrode 25 is installed below the reaction chamber 21 via an insulator 26, and the substrate 2 is placed on the lower electrode 25.
7 is installed. 28 is a gas exhaust hole installed on the lower side surface of the reaction chamber 1, 29 is the reaction chamber 21
A reaction gas introducing hole provided on the side surface of the lower electrode 25 is a high frequency power source for applying high frequency power to the lower electrode 25 as needed.

[0005]

By the way, in the high-density plasma processing apparatus having the above-mentioned structure, the reaction gas is introduced from the reaction gas introduction hole 29 provided on the side surface of the reaction chamber 21, so that the lower electrode is formed. There is a problem that it is difficult to make the reaction gas that hits the substrate 27 placed on the substrate 25 uniform, and it is difficult to obtain a uniform film formation rate and etching rate.

In view of the above conventional problems, it is an object of the present invention to provide a plasma processing method and apparatus which are excellent in uniformity of processing speed such as film forming speed and etching speed.

[0007]

In the plasma processing method of the present invention, a substrate is installed on a lower electrode in the lower part of a reaction chamber, and a dielectric plate installed on the upper surface of the reaction chamber and at least two or more installed below the dielectric plate. A gas provided on the side surface of the reaction chamber below the gas dispersion plate by introducing the reaction gas from the reaction gas introduction hole provided on the side surface of the reaction chamber into the space between the dielectric gas distribution plate having holes. Gas is exhausted from the exhaust hole, high-frequency power is applied to the induction coil installed on the dielectric plate, plasma is generated between the gas dispersion plate and the lower electrode, and the substrate installed on the lower electrode is processed. The reaction gas that hits the substrate on the lower electrode is made uniform by the dispersion plate to improve the uniformity of the film formation rate and the etching rate. In addition, the distance between the dielectric plate and the gas dispersion plate is set to 10 mm or less, and the pressure during plasma discharge is set to 10 mTorr or more, so that the distance between the dielectric plate and the gas dispersion plate is set to be equal to or less than the mean free path of the gas, and molecules are Prevents film formation due to discharge between the dielectric plate and gas dispersion plate by preventing sufficient energy for ionization, resulting in increased particles, decreased film formation rate, and uniform film thickness. It is designed to prevent deterioration of the sex over time.

Further, the first reaction gas is introduced from the first reaction gas introduction hole provided on the side surface of the reaction chamber into the space between the dielectric plate and the gas dispersion plate, and the first reaction gas is introduced between the gas dispersion plate and the lower electrode. From the second reaction gas introduction hole provided on the side surface of the reaction chamber of
Of the reaction gas is introduced, plasma is generated between the gas dispersion plate and the lower electrode, and the first reaction gas and the second reaction gas react with each other to process the substrate placed on the lower electrode. The plate homogenizes the reaction gas that hits the substrate on the lower electrode, and prevents the formation of a film between the dielectric plate and the gas dispersion plate, resulting in an increase in particles and a decrease in the film formation rate. The film thickness uniformity is prevented from deteriorating with time.

Further, according to the plasma processing apparatus of the present invention, the dielectric plate provided on the upper surface of the reaction chamber, the induction coil for applying high frequency power installed on the dielectric plate, and the substrate provided in the reaction chamber are provided. A lower electrode to be installed, a dielectric gas dispersion plate having at least two holes provided between the dielectric plate and the lower electrode, and a reaction provided on the side surface of the reaction chamber between the dielectric plate and the gas dispersion plate. A gas introduction hole and a gas exhaust hole provided on the side surface of the reaction chamber below the gas dispersion plate are provided, and the reaction gas is configured to flow from the gas dispersion plate to the substrate installed on the lower electrode. The reaction gas that hits the substrate on the lower electrode is made uniform by the gas dispersion plate to improve the uniformity of the film formation rate and the etching rate.

Further, in the above plasma processing apparatus, by setting the thickness of the gas dispersion plate to 5 mm or more, when the reaction chamber is evacuated from the vicinity of atmospheric pressure, a pressure difference occurs due to the conductance of the holes of the gas dispersion plate. It is possible to prevent the gas dispersion plate from cracking.

Alternatively, a first gas exhaust hole provided on the side surface of the reaction chamber around the lower electrode, a second gas exhaust hole provided on the side surface of the reaction chamber below the gas dispersion plate, and a dielectric plate. And a third gas exhaust hole provided on the side surface of the reaction chamber between the gas dispersion plate and the reaction gas for the substrate installed on the lower electrode from the gas dispersion plate by exhausting from the first exhaust hole during plasma processing. Even when the reaction chamber is evacuated and the gas is exhausted from the second gas exhaust hole and the third gas exhaust hole when the reaction chamber is evacuated, the gas dispersion plate is It can prevent cracking.

Further, the distance between the dielectric plate and the gas dispersion plate is 10
mm or less and the pressure during plasma discharge is 10 mTo
By setting it to be rr or more, it is possible to prevent the discharge from occurring between the dielectric plate and the gas dispersion plate to form a film as described above, which results in an increase in particles, a decrease in the film formation rate, and a deterioration of the film thickness uniformity over time. Can be prevented.

Further, as reaction gas introduction holes, a first reaction gas introduction hole for introducing a first reaction gas, which is provided on a side surface of the reaction chamber between the dielectric plate and the gas dispersion plate, and the gas dispersion plate and the lower electrode are provided. By providing the second reaction gas introduction hole for introducing the second reaction gas provided on the side surface of the reaction chamber between them, a film is formed between the dielectric plate and the gas dispersion plate as described above. It is possible to prevent the increase of particles, the decrease of the film forming speed, and the deterioration of the film thickness uniformity with the lapse of time.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

(First Embodiment) A high-density plasma CVD apparatus according to the first embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 is a reaction chamber, the upper surface of which is constituted by a dielectric plate 2 made of a dielectric material such as quartz, and an induction coil 3 is installed thereon. The induction coil 3 is configured to apply high frequency power of, for example, 13.56 MHz from the high frequency power source 4. A lower electrode 5 is installed below the reaction chamber 1 via an insulator 6, and a substrate 7 is installed on the lower electrode 5. Reference numeral 8 denotes an exhaust chamber formed around the lower electrode 5 below the reaction chamber 1. The exhaust chamber 8 is partitioned into a space inside the reaction chamber 1 by an annular rectifying plate 9 and formed in the annular partition plate 9. Is communicated with the space above the lower electrode 5 of the reaction chamber 1 via the communication hole 10. Reference numeral 11 denotes a gas exhaust hole provided on the side surface of the exhaust chamber 8.

Reference numeral 12 denotes a gas dispersion plate installed between the dielectric plate 2 and the lower electrode 5, which is made of a dielectric material such as quartz.
As shown in FIG. 2, the hole diameter is 0.5 to 2 mm and the interval is 5
~ 20mm, the total number of holes is about 50 ~ 5000 13
Are formed. The distance between the dielectric plate 2 and the gas dispersion plate 12 is set to 10 mm or less, and the gas dispersion plate 1
2 has a thickness of 5 mm or more. A reaction gas introduction hole 14 is formed on the side surface of the reaction chamber 1 between the dielectric plate 2 and the gas dispersion plate 12. 20 is a lower electrode 5 if necessary
It is a high-frequency power source that applies high-frequency power to.

In the above structure, first, the substrate 7 is placed on the lower electrode 5, and the inside of the reaction chamber 1 is sufficiently evacuated. When the reaction chamber 1 is evacuated from around atmospheric pressure, the conductance of the holes 13 of the gas dispersion plate 12 causes the reaction chamber 1 to have a higher pressure than the pressure in the space between the dielectric plate 2 and the gas dispersion plate 12. Although the internal pressure drops sharply, by setting the thickness of the gas distribution plate 12 to 5 mm or more, it is possible to prevent the gas distribution plate 12 from cracking due to this pressure difference. In such a vacuumed state, silane gas and oxygen gas are introduced between the dielectric plate 2 and the gas dispersion plate 12 through the gas introduction hole 14, the gas is exhausted through the gas exhaust hole 11, and the pressure in the reaction chamber 1 is reduced. Is maintained at 10 mTorr and a high frequency power of, for example, 13.56 MHz is applied to the induction coil 3 on the dielectric plate 2 to generate plasma in the space between the gas dispersion plate 12 and the lower electrode 5 and the substrate 9 surface. A SiO ₂ film is formed on. At this time, the gas dispersion plate 12 is formed on the lower electrode 5 by the substrate 7
The reaction gas is uniformly sprayed onto the substrate, and the film thickness uniformity within the substrate surface is improved.

Further, the distance between the dielectric plate 2 and the gas dispersion plate 12 is 10 mm or less, and the pressure during plasma discharge is 1
By setting it to 0 mTorr or more, that is, by setting the distance between the dielectric plate 2 and the gas dispersion plate 12 to be equal to or less than the mean free path of gas, electrons frequently collide with gas molecules to excite gas molecules, and collide with each other. Since it is not possible to obtain enough energy to ionize the molecules during, it is possible to prevent discharge (film formation) between the dielectric plate 2 and the gas dispersion plate 12, and It is possible to prevent an increase in particles, a decrease in film formation rate, and deterioration of film thickness uniformity over time due to the above.

(Second Embodiment) Next, a high density plasma CVD apparatus according to a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment described with reference to FIGS. 1 and 2 are designated by the same reference numerals and description thereof will be omitted, and only different points will be described.

In FIG. 3, the gas exhaust hole 11 is used as the first gas exhaust hole, and the second gas exhaust hole 15 is provided on the side surface of the reaction chamber 1 between the gas dispersion plate 12 and the lower electrode 5 and the dielectric plate 2 is provided. Third gas exhaust holes 16 are provided on the side surface of the reaction chamber 1 between the gas dispersion plate 12 and the gas dispersion plate 12. The first gas exhaust hole 11 is connected to a vacuum exhaust source (not shown) via a first valve 17, and the second and third gas exhaust holes 15 and 16 are connected to a vacuum exhaust source via a second valve 18. (Not shown).

In the above structure, when the reaction chamber 1 is evacuated from the vicinity of the atmospheric pressure, it is simultaneously exhausted from the second gas exhaust hole 15 and the third gas exhaust hole 16, and the pressure in the reaction chamber 1 is reduced. Is about 100 Torr or less, exhaust is performed only through the first exhaust holes 11. By doing so, when the reaction chamber 1 is evacuated from the vicinity of the atmospheric pressure, the gas dispersion plate 12
Even if the conductance of the hole 13 is present, the pressure between the dielectric plate 2 and the gas dispersion plate 12 and the rate of decrease in the pressure of the reaction chamber 1 below the gas dispersion plate 12 can be made the same, and the dielectric It is possible to prevent cracking of the gas dispersion plate 12 made of. In this case, the diameters of the second and third gas exhaust holes 15 and 16 are set such that the second gas exhaust hole 15 is 1/2 inch and the third gas exhaust hole 16 is 1/4 inch. It is effective to change the diameter of the exhaust hole depending on the ratio of the volume of the reaction chamber 1 below the plate 12 to the volume of the reaction chamber 1 between the dielectric plate 2 and the gas dispersion plate 12.

(Third Embodiment) Next, a high density plasma CVD apparatus according to a third embodiment of the present invention will be described with reference to FIG. The same components as those of the second embodiment described with reference to FIG. 3 are designated by the same reference numerals, the description thereof will be omitted, and only different points will be described.

In FIG. 4, the reaction gas introduction hole 14 is shown as the first
The second reaction gas introduction hole 19 for introducing the second reaction gas is formed on the side surface of the reaction chamber 1 between the gas dispersion plate 12 and the lower electrode 5 as the first reaction gas introduction hole for introducing the reaction gas. Has been formed.

In the above structure, for example, when the SiO ₂ film is formed by the reaction of silane gas and oxygen gas, oxygen gas is introduced through the first reaction gas introduction hole 14 and silane gas is introduced through the second reaction gas. It is introduced through the hole 19. As described above, when the first reaction gas introduced through the first reaction gas introduction hole 14 and the second reaction gas introduced through the second reaction gas introduction hole 19 react to form a film on the substrate 7. The effect of preventing the formation of a film between the dielectric plate 2 and the gas dispersion plate 12, and thereby preventing the increase of particles, the decrease of the film formation rate, and the deterioration of the film thickness uniformity over time due to the film formation. There is.

In the above description, an example in which quartz is used as the material of the gas dispersion plate 12 has been described, but a dielectric such as silicon nitride, aluminum oxide, or boron nitride can be similarly applied.

Further, although described in example of forming the SiO ₂ film by a reaction of silane gas and oxygen gas, and silane gas and nitrous oxide gas may form a SiO ₂ film by a reaction of tetraethoxysilane and oxygen gases Alternatively, SiOF may be formed by adding an F-based gas such as SiF ₄ , CF ₄ , C ₂ F ₆ as an additive gas. Alternatively, film formation may be performed while adding argon gas and applying high frequency power of about 450 KHz to the lower electrode 5 by the high frequency power supply 20 to perform physical etching. Further, the same can be applied to the case of forming the Si ₃ N ₄ film by the reaction of the silane gas and the ammonia gas, and further, the etching can be performed by introducing the argon gas.

[0027]

According to the plasma processing method of the present invention, as is clear from the above description, the dielectric plate having the dielectric plate installed on the upper surface of the reaction chamber and at least two holes installed below the dielectric plate is used. Film is formed by introducing the reaction gas into the space between the gas dispersion plate and the gas dispersion plate through the gas introduction hole provided on the side surface of the reaction chamber and homogenizing the reaction gas hitting the substrate on the lower electrode by the gas dispersion plate. The uniformity of the etching rate and the etching rate can be improved, the distance between the dielectric plate and the gas dispersion plate is 10 mm or less, and the pressure during plasma discharge is 10 m.
By setting the pressure to Torr or more, it is possible to prevent electric discharge from occurring between the dielectric plate and the gas dispersion plate to form a film, and to prevent an increase in particles, a decrease in the film formation rate, and deterioration of the film thickness uniformity over time due to that. You can

Further, the first reaction gas is introduced into the space between the dielectric plate and the gas dispersion plate through the first reaction gas introduction hole provided on the side surface of the reaction chamber, and the first reaction gas is introduced between the gas dispersion plate and the lower electrode. From the second reaction gas introduction hole provided on the side surface of the reaction chamber of
By introducing the reaction gas of, the reaction gas hitting the substrate on the lower electrode is made uniform by the gas dispersion plate,
It is possible to prevent a film from being formed between the dielectric plate and the gas dispersion plate, and to prevent an increase in particles, a decrease in film formation rate, and deterioration of film thickness uniformity over time due to the formation of a film.

Further, according to the plasma processing apparatus of the present invention, a dielectric gas dispersion plate having at least two holes is provided between the dielectric plate and the lower electrode, and the reaction between the dielectric plate and the gas dispersion plate is performed. Since the reaction gas introduction hole is provided on the side surface of the chamber so that the reaction gas flows from the gas dispersion plate to the substrate installed on the lower electrode, the reaction that hits the substrate on the lower electrode by the gas dispersion plate The gas can be made uniform, and the uniformity of the film formation rate and the etching rate can be improved.

Further, in the above plasma processing apparatus, by setting the thickness of the gas dispersion plate to 5 mm or more, when the reaction chamber is evacuated from the vicinity of atmospheric pressure, a pressure difference is generated due to the conductance of the holes of the gas dispersion plate. It is possible to prevent the gas dispersion plate from cracking.

Alternatively, during the plasma processing, the reaction gas is exhausted from the first exhaust hole provided on the lower side surface of the reaction chamber to allow the reaction gas to flow from the gas dispersion plate to the substrate installed on the lower electrode. During evacuation, from a second gas exhaust hole provided on the side surface of the reaction chamber between the exhaust chamber and the gas dispersion plate and a third gas exhaust hole provided on the side surface of the reaction chamber between the dielectric plate and the gas dispersion plate. By exhausting the gas, it is possible to prevent the gas dispersion plate from cracking when the reaction chamber is evacuated from around atmospheric pressure.

The distance between the dielectric plate and the gas dispersion plate is 10
mm or less and the pressure during plasma discharge is 10 mTo
By setting it to be rr or more, it is possible to prevent the discharge from occurring between the dielectric plate and the gas dispersion plate to form a film as described above, which results in an increase in particles, a decrease in the film formation rate, and a deterioration of the film thickness uniformity over time. Can be prevented.

Further, as the reaction gas introduction holes, a first reaction gas introduction hole for introducing the first reaction gas, which is provided on the side surface of the reaction chamber between the dielectric plate and the gas dispersion plate, and the gas dispersion plate and the lower electrode are provided. By providing the second reaction gas introduction hole for introducing the second reaction gas provided on the side surface of the reaction chamber between them, a film is formed between the dielectric plate and the gas dispersion plate as described above. It is possible to prevent the increase of particles, the decrease of the film forming speed, and the deterioration of the film thickness uniformity with the lapse of time.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a plasma CVD apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view of a gas dispersion plate in the same embodiment.

FIG. 3 is a vertical sectional front view of a plasma CVD apparatus according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional front view of a plasma CVD apparatus according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a conventional plasma CVD apparatus.

[Explanation of symbols]

1 reaction chamber 2 Dielectric plate 3 induction coil 4 high frequency power supply 5 Lower electrode 7 substrate 11 (First) gas exhaust hole 12 Gas dispersion plate 13 holes 14 (First) reaction gas introduction hole 15 Second gas exhaust hole 16 Third gas exhaust hole 19 Second reaction gas introduction hole

Continuation of front page (56) Reference JP-A-7-122399 (JP, A) JP-A-7-73997 (JP, A) JP-A-7-312348 (JP, A) JP-A-7-78811 (JP , A) JP-A-6-61153 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/205 C23C 16/50 H01L 21/285 H01L 21/3065

Claims (7)

(57) [Claims] 1. A substrate is installed on the lower electrode in the lower part of the reaction chamber, and a dielectric plate installed on the upper surface of the reaction chamber and 10 mm below the dielectric plate.
A reaction gas is introduced from a reaction gas introduction hole provided on the side surface of the reaction chamber into a space between the gas dispersion plate made of a dielectric material and having at least two holes installed at the following intervals. Gas is exhausted from the gas exhaust hole provided on the side surface of the lower reaction chamber, the pressure in the reaction chamber is adjusted to 10 mTorr or more, and high frequency power is applied to the induction coil installed on the dielectric plate, the gas dispersion plate and the lower electrode. A plasma processing method, wherein plasma is generated between the substrates to process the substrate placed on the lower electrode. 2. A dielectric plate installed on the lower electrode in the lower part of the reaction chamber, the dielectric plate installed on the upper surface of the reaction chamber and the dielectric gas dispersion plate having at least two holes installed below the dielectric plate. The first reaction gas is introduced into the space between the first reaction gas introduction holes provided on the side surface of the reaction chamber, and the second reaction is provided on the side surface of the reaction chamber between the gas dispersion plate and the lower electrode. The second reaction gas is introduced from the gas introduction hole and exhausted from the gas exhaust hole provided on the side surface of the reaction chamber below the gas dispersion plate,
High frequency power was applied to the induction coil installed on the dielectric plate, plasma was generated between the gas dispersion plate and the lower electrode, and the reaction was performed between the first reaction gas and the second reaction gas to install the plasma on the lower electrode. A plasma processing method, which comprises processing a substrate. 3. A dielectric plate installed on the upper surface of the reaction chamber, and an induction coil installed on the dielectric plate for applying high frequency power.
Reaction between the lower electrode for mounting the substrate provided in the reaction chamber, the gas dispersion plate made of a dielectric material having at least two holes provided between the dielectric plate and the lower electrode, and the reaction between the dielectric plate and the gas dispersion plate A reaction gas introduction hole provided on the side surface of the chamber, and a gas exhaust hole provided on the side surface of the reaction chamber below the gas dispersion plate, and the reaction gas to the substrate installed on the lower electrode from the gas dispersion plate. A plasma processing apparatus, which is configured to flow. 4. The plasma processing apparatus according to claim 1, wherein the gas dispersion plate has a thickness of 5 mm or more. 5. A dielectric plate installed on the upper surface of the reaction chamber, an induction coil installed on the dielectric plate for applying high frequency power,
Reaction between the lower electrode for mounting the substrate provided in the reaction chamber, the gas dispersion plate made of a dielectric material having at least two holes provided between the dielectric plate and the lower electrode, and the reaction between the dielectric plate and the gas dispersion plate A reaction gas introduction hole provided on a side surface of the chamber, a first gas exhaust hole provided on a side surface of the reaction chamber around the lower electrode, and a second gas exhaust hole provided on a side surface of the reaction chamber below the gas dispersion plate. Gas exhaust hole and a third gas exhaust hole provided on the side surface of the reaction chamber between the dielectric plate and the gas dispersion plate. During plasma processing, gas is exhausted from the first exhaust hole to the lower electrode from the gas dispersion plate. A plasma processing apparatus configured to allow a reaction gas to flow to an installed substrate and to exhaust gas from a second gas exhaust hole and a third gas exhaust hole when a reaction chamber is evacuated. 6. The distance between the dielectric plate and the gas dispersion plate is 10 mm.
Below, the pressure at the time of plasma discharge is 10 mTorr
The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus is configured as described above. 7. A dielectric plate installed on the upper surface of the reaction chamber, an induction coil installed on the dielectric plate for applying high frequency power,
Reaction between the lower electrode for mounting the substrate provided in the reaction chamber, the gas dispersion plate made of a dielectric material having at least two holes provided between the dielectric plate and the lower electrode, and the reaction between the dielectric plate and the gas dispersion plate A first reaction gas introduction hole provided on the side surface of the chamber for introducing the first reaction gas, and a second reaction gas provided on the side surface of the reaction chamber between the gas dispersion plate and the lower electrode 2 reaction gas introduction holes, a first gas exhaust hole provided on the side surface of the reaction chamber around the lower electrode, and a second gas exhaust hole provided on the side surface of the reaction chamber below the gas dispersion plate. ,
A third gas exhaust hole provided on the side surface of the reaction chamber between the dielectric plate and the gas dispersion plate, and exhausted from the first exhaust hole during plasma processing to the substrate installed on the lower electrode from the gas dispersion plate; A plasma processing apparatus configured to allow a reaction gas to flow and to exhaust gas from a second gas exhaust hole and a third gas exhaust hole when a reaction chamber is evacuated.