JPH043417A - Method and apparatus for plasma processing - Google Patents

Abstract

PURPOSE:To improve diffusion of gas flows and even surface finishing, such as coating and etching, of a processed material by making a plurality of gas dispersion holes in the direction of the diameter in the side of a diffusion chamber under an electrode. CONSTITUTION:Gas supplied from a gas box is introduced to a first electrode 20 through a gas introduction tube 5 and into a first diffusion chamber 14a through a gas introduction path 13. The gas after wide first-step diffusion in the first diffusion chamber 14a is introduced into a second diffusion chamber 14b for second-step diffusion through the many passing holes 15a of a first diffusion plate 15 made to keep the degree of diffusion. The diffused gas in the second diffusion chamber 14b is introduced into a third diffusion chamber 14c for third-step diffusion through the many passing holes 16a of a second diffusion plate 16. The diffused gas in the third diffusion chamber 14c is introduced into a vacuum container 1 for diffusion through the many passing holes 17a of a third diffusion plate 17. Thereby gas is distributed uniformly on a processed material 8 and a film is formed and etching is performed uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma processing apparatus and a plasma processing method that perform film formation, etching, etc. on an object to be processed, such as a semiconductor wafer, using reactive gas plasma.

[Conventional technology]

FIG. 6 is a schematic vertical cross-sectional view showing the plasma processing apparatus of the present invention. In the figure, 1 is a vacuum vessel, in which a first electrode 2 and a second electrode 3 are disposed facing each other, and a gas exhaust n4 is provided at the bottom.

5 is a gas introduction pipe connected to the first electrode 2 and introducing a reactive gas from an external gas supply source (not shown); 6 is a second gas introduction pipe;
7 is a matching box for matching between the second electrode 3 and the high frequency power source 6. 08 is placed on the second electrode 35. An object to be processed, such as a semiconductor wafer. 1st
The electrode 2 has a gas introduction mechanism in which gas is introduced from above, diffused in a diffusion chamber in the lower part, and discharged downward.

FIG. 7 is a longitudinal sectional view of a first electrode section having a gas introduction mechanism section showing a conventional plasma processing apparatus.

In the figure, a gas introduction mechanism is formed in the first electrode 10 as follows. A disk portion 12 is provided at the bottom of the columnar portion 11.
are integrally formed, a gas introduction path 13 is provided in the columnar portion 11, and a gas diffusion chamber 14 is provided in the disc portion 12. Reference numeral 15 denotes a first diffusion plate fixed in the gas diffusion chamber 14, which is provided with a large number of communication holes 15a, and is partitioned into a first diffusion chamber 14a on one side and a second diffusion chamber 14b on the upper and lower sides. , guides the gas in the diffusion chamber 14a to the diffusion chamber 141). 16
is a second diffusion plate fixed in the gas diffusion chamber 14, which is provided with a large number of communication holes 16a, and which is connected to the second diffusion chamber 14b.
Divided into upper and lower third diffusion chambers 14c, diffusion chamber 14t
) is introduced into the diffusion chamber 14c. Reference numeral 17 denotes a third diffusion plate fixed to the lower end of the disk portion 12, which is provided with a large number of communication holes 172L, and guides the gas in the diffusion chamber 14c into the vacuum container 1. Arrow A is a vector representing the direction and magnitude of gas flow, and dotted line B is a flow velocity line segment right curve representing the magnitude of gas flow flowing out from each diffusion plate 15, 16, 17.

Next, the operation will be explained. First, in FIG. 6, the gas (generally atmospheric air) inside the vacuum container 1 in which the object to be processed 8 is placed on the second electrode 3 is brought to a predetermined pressure through the gas exhaust port 4 by a vacuum pump (not shown). Exhaust until next,
A required gas is introduced from a gas box (not shown) which is a gas supply source into the vacuum vessel 1 through the first electrode 2 through the gas introduction pipe 5. The amount of gas exiting from the gas exhaust port 4 is controlled by a regulating valve (not shown) or the like, and adjusted to a predetermined pressure.

Subsequently, a voltage is applied from the high frequency power source 6 through the matching box 7 between the second electrode 3 and the first electrode 2 to generate plasma. The diffusion effect of the introduced gas by the first electrode 1o, which uses this plasma to perform surface treatments such as thin film formation and etching on the object to be processed 8, will be explained with reference to FIG. Gas from the gas introduction pipe 5 is introduced into the first diffusion chamber 14a through the gas introduction path 13. Here, the gas diffused in the first stage is introduced into the second expansion chamber 141) through each communication hole 15a of the first diffusion plate 15 provided so as not to impair the rate of diffusion. Perform eye diffusion. Subsequently, the gas flows through each of the circulation holes 16 of the second diffusion plate 16.
a, and is introduced into the third diffusion chamber 14c to perform the third stage of diffusion.

The gas diffused in the third stage is distributed through each circulation hole 1 of the third diffusion plate 1.
7 a and diffuses above the object to be processed 8 in the vacuum container 1 .

The direction and magnitude of the gas flow from the gas introduction path 13 to the inside of the vacuum container 1 are as shown by the vector shown by the arrow A, and the diffused gas is shown by the right curve B of the flow velocity line.

[Problems to be Solved by the Invention] In the conventional plasma processing apparatus as described above, in the gas introduction mechanism of the first electrode 2, the gas passing through the gas introduction path 13 at high speed is connected to the diffusion chamber 14 and the diffusion plate. 15 to 17, and the gas diffuses into the vacuum container 1 with an uneven flow velocity distribution, resulting in a decrease in the uniformity of film formation and etching on the object to be processed 8. This invention was made to solve these problems, and it allows the gas flow to be sufficiently diffused in the diffusion chamber, and to diffuse it in the vacuum container with a uniform velocity distribution.
The object of the present invention is to provide a plasma processing apparatus and a plasma processing method having a gas introduction mechanism, which improve the uniformity of surface treatments such as film formation and etching on objects to be processed.

[Means to solve the problem]

The plasma processing apparatus and plasma processing method according to the present invention include a plurality of radial gas dispersion holes arranged on the side of a diffusion chamber formed under the first electrode to uniformize gas diffusion in the diffusion chamber, It is designed to diffuse above the object to be processed.

[Effect]

In this invention, the gas introduced into the diffusion chamber through the gas introduction path of the first electrode is sufficiently diffused in the diffusion chamber in advance by the flow force generated in the lateral direction by the side gas distribution holes. As a result, the gas in the diffusion chamber passes through the many flow holes in the diffusion plate and is released toward the object to be processed in the vacuum container, but the flow velocity distribution becomes uniform, good diffusion is obtained, and the coating on the object to be processed is made uniform. The uniformity of surface treatments such as etching and etching can be improved.

〔Example〕

FIG. 1 is a longitudinal sectional view of a first electrode section having a gas introduction mechanism section showing a plasma processing apparatus according to an embodiment of the present invention. In the figure, reference numeral 20 denotes a first electrode having a gas introduction mechanism, and a disk-shaped portion 22 is integrally formed at the bottom of the columnar portion 11. A gas introduction path 13 is provided in the columnar portion 11, and a disk-shaped portion 22 is integrally formed at the bottom of the columnar portion 11. A diffusion chamber 14 is formed in the shaped portion 22 . A first diffusion plate 15 is provided inside the diffusion chamber 14 and at the lower end. Second diffuser plate 16
and a third diffusion plate 17 are fixed to partition the diffusion chamber 14 into a first diffusion chamber 14a, a second diffusion chamber 141), and a third diffusion chamber 14C. First diffuser plate 15. A large number of communication holes 15a, 16a and 17a are provided in the second expansion plate 16 and the third expansion plate 1, respectively.

A plurality of gas dispersion holes 23 are bored in the radial direction on the side of the diffusion chamber 14a of the disc-shaped portion 22. Reference numeral 24 denotes a movable ring supported rotatably in the circumferential direction on the outer circumference of the disc-shaped portion 22, and includes a plurality of communication holes 2 corresponding to each gas dispersion hole 23.
5 is opened in the radial direction. RL of communication hole 25! The diameter is larger than the diameter of the gas branch hole 23.

FIG. 2 is a cross-sectional view of the disk-shaped portion 22 and the movable ring 24 in which the gas dispersion holes 23 and the communication holes 25 are provided.
It is shown in front view in FIG.

FIG. 4 shows a state in which the movable ring 24 for one pair of the gas dispersion hole 23 and the communication hole 25 is rotated and adjusted.

In the figure (a), the opening area is maximized when the communication hole 25 is located concentrically with the gas distribution hole 23.

In the figure (b), the movable ring 24 is rotated by the amount of movement in the direction of the arrow, thereby reducing the opening area of the gas fraction hole 23.

In the figure (C), the movable ring 24 is rotated by the amount of movement E in the direction of the arrow, and closes the gas dispersion hole 23.

The other components of the plasma processing apparatus having the first electrode 2o are the same as those shown in FIG. 6 above.

Next, the operation of the apparatus of the above embodiment will be explained.

As shown in FIG. 6, a supply gas from a gas box (not shown) is introduced into the first electrode 20 through a gas introduction pipe 5. As shown in FIG. In FIG. 1, gas from the gas introduction pipe 5 passes through the gas introduction path 13 and is introduced into the first expansion chamber 14a. A portion of the gas introduced here escapes into the vacuum container 1 through the gas fraction hole 23.

The gas pressure in the first expansion chamber 14a is PH (Pa), the gas pressure in the vacuum container 1 is P2 (Pa), the cross-sectional area of the gas fraction hole 23 is S (m2), and the force acting on the gas fluid is F (N). Then, F=(PI-P2)8>O(N).

Here, PI>P2.

As a result, the gas in the first diffusion chamber 14a flows in the lateral direction (
Therefore, the gas in the first diffusion chamber 14a is more diffused than in the conventional case.

At this time, the opening area of the gas dispersion hole 23 is adjusted by rotating the movable ring 24 supported on the outer circumference of the disk-shaped portion 22 of the first electrode 20 (see FIG. 4, 8). ) shi,
The magnitude of the force F (N) of the gas in the first diffusion chamber 14a in the C direction is adjusted, and the amount of gas diffusion in the C direction is controlled. The amount of gas diffusion in the C direction is maximum in Fig. 4(a), becomes smaller as shown in Fig. 4(b), and becomes zero in Section 4 1(c), which is equivalent to the conventional one. becomes.

As described above, the gas that has been largely diffused in the first stage in the first expansion chamber 14a has a large number of circulation holes 15a in the first diffusion plate 15 provided so as not to impair the rate of diffusion. The gas is then introduced into the second diffusion chamber 14b, where a second stage of diffusion is performed. The diffused gas in the second diffusion chamber 141) passes through the numerous communication holes 16c of the second diffusion plate 16, and passes through the third diffusion chamber 1.
4c and performs the third stage of diffusion. Third diffusion chamber 14
The diffused gas c passes through the many communication holes 17a of the third diffusion plate 17, enters the vacuum container 1, and diffuses therein.

At this time, the movable ring 24 is rotated so that the gas flow distribution becomes like the flow vector A1 and the velocity line distribution curve B.
Adjust the amount of directional spread.

In this way, the gas is uniformly discharged from the flow holes 17a of the third diffusion plate 17 in wave numbers, the gas distribution above the object to be processed 8 is made uniform, and the uniformity in film formation and etching is improved.

FIG. 5 shows another embodiment of the invention. In the figure, a diffusion chamber 33 is formed in the disc-shaped portion 32 of the first electrode 30,
A plurality of gas dispersion holes 34 are provided on the side of the diffusion chamber 33 . A diffusion plate 35 is fixed to the lower end of the diffusion chamber 33,
A movable ring 44 is rotatably supported on the outer circumference of the disc-shaped portion 32, and a side portion of the movable ring 44 is provided with a plurality of flow holes 35a. A communication hole 45 corresponding to the distribution hole 34 is provided.

In this way, one diffusion plate 35 is used to uniformly distribute the gas into the vacuum container 1. In the embodiment shown in FIG. Although the gas distribution holes 23 are provided in the second diffusion chamber 141), the gas distribution holes may be provided in the sides of the second diffusion chamber 141) or the third expansion chamber 14c.

In addition, in the above embodiment, the movable ring 24.44 is provided so that the opening area of the gas distribution hole 23.34 can be adjusted. The ring may be omitted.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of radial gas dispersion holes are provided in the side of the diffusion chamber formed at the bottom of the first electrode, so that gas can be sufficiently diffused within the diffusion chamber. Therefore, the diffusion gas in the diffusion chamber is uniformly distributed in the vacuum chamber through the many circulation holes of the diffusion plate, and the uniformity of surface treatment such as film formation or etching of the object to be treated on the second electrode is improved. 0

[Brief explanation of drawings]

FIGS. 1 (&) and (1)) are a vertical sectional view and a bottom view of a first electrode section having a gas introduction mechanism section showing a plasma processing apparatus according to an embodiment of the present invention, and FIG. 2 is a view similar to FIG. (a)-1
3 is a front view of the movable ring section shown in FIG. , FIG. 5 is a longitudinal cross-sectional view and a bottom view of a first electrode section having a gas introduction mechanism section showing a plasma processing apparatus according to another embodiment of the present invention, and FIG.
The figure is a schematic vertical sectional view of a plasma processing apparatus, and FIGS. 7(-) and 7(b) are a longitudinal sectional view and a bottom view of a first electrode section having a gas introduction mechanism section showing a conventional plasma processing apparatus. DESCRIPTION OF SYMBOLS 1... Vacuum container, 3... Second electrode, 5... Gas introduction tube, 6... High frequency power supply, 8... Processed object, 13...
- Gas introduction path, 14...diffusion chamber, 14a...first diffusion chamber, 14b...second diffusion chamber, 14c...third diffusion chamber, 15...first diffusion plate, 16...・Second diffusion plate, 17
...Third diffusion plate, 15a. 16a, 17a... communication hole, 20... first electrode,
23... Gas distribution hole, 24... Movable ring, 25...
...Communication hole, 30...First electrode, 33...Diffusion chamber, 34...Gas dispersion hole, 35...Diffusion plate, 35a.
. . . Communication hole, 44 . . . Movable ring, 45 . . Communication hole. In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A first electrode and a second electrode are vertically opposed to each other in a vacuum container, the object to be processed is placed on the second electrode, and the first electrode is exposed to an external source. A gas introduction hole for introducing gas from the top and a diffusion chamber formed at the bottom in communication with the gas introduction hole are provided, and a diffusion plate with a large number of circulation holes is attached to the lower end of the diffusion chamber. In a plasma processing apparatus that diffuses gas guided into the diffusion chamber above the object to be processed through a diffusion plate, applies a voltage between both electrodes, turns the diffused gas into plasma, and performs surface treatment on the object to be processed. , A plurality of radial gas dispersion holes are provided in the side of the diffusion chamber of the first electrode, so that the diffusion gas in the diffusion chamber is made uniform, and the uniform diffusion gas is discharged above the object to be processed. plasma processing equipment. (2) A movable ring is movably supported in the circumferential direction on the outer side of the diffusion chamber of the first electrode, and the movable ring is provided with a plurality of communication holes in the radial direction corresponding to each gas dispersion hole, 2. The plasma processing apparatus according to claim 1, wherein the movable ring is rotated to adjust the opening area of the gas dispersion hole to uniformly diffuse the gas within the diffusion chamber. (3) The first electrode and the second electrode are vertically opposed to each other in a vacuum container, the object to be processed is placed on the second electrode, and the
Gas from the outside is introduced into the electrode from the top and diffused into the diffusion chamber at the bottom, and some of the gas is dispersed in the radial direction by multiple radial gas distribution holes arranged on the side of this diffusion chamber. , uniformize the gas diffusion in the diffusion chamber, pass the diffusion gas from the diffusion chamber through the many circulation holes of the lower end diffusion plate to uniformly diffuse it downward, and apply a voltage between the above two electrodes to turn the diffusion gas into plasma. , a plasma processing method for surface-treating the object to be processed;