JP2972507B2 - Microwave plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma processing apparatus, and more particularly to a microwave plasma processing apparatus suitable for ashing a semiconductor substrate or the like.

[0002]

2. Description of the Related Art As a conventional microwave plasma processing apparatus, for example, as described in JP-A-63-122123, a circular waveguide which is connected to a processing chamber provided with a sample stage and serves as a plasma generation chamber is disclosed. A discharge tube having a reflective end having a plurality of small diameter holes attached to a lower opening thereof, and a concave surface parallel to a sample stage attached to an upper opening of a circular waveguide to which a microwave waveguide is connected. Is set to 1/8 or more of the guide wavelength of the microwave to generate plasma efficiently, and by providing the surface between the reflection end and the wafer in parallel, the uniformity over the entire surface of the wafer is obtained. There is known an apparatus capable of performing an ashing process so that a wafer can be processed quickly and uniformly.

[0003]

The above prior art does not take into consideration the control of microwaves in the waveguide, and does not improve the efficiency of microwave transmission to the plasma generation chamber. In addition, a sufficient ashing processing speed and an in-plane uniformity of an assig processing speed could not be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to control microwaves in a waveguide so that microwaves can be efficiently introduced into a plasma generation chamber to increase the plasma generation efficiency, to achieve a high ashing processing speed, and to achieve an ashes. An object of the present invention is to provide a microwave plasma processing apparatus having good processing speed in-plane uniformity.

[0005]

The object of the present invention is to provide a plasma generation chamber, means for supplying a processing gas to the plasma generation chamber,
A processing chamber connected to one end of the plasma generation chamber via a punching metal, a means for evacuating the processing chamber, and a connection end of the plasma generation chamber connected to the other end of the plasma generation chamber via a microwave introduction window. micro transmitted through the rectangular waveguide have a enlarged space having a predetermined size
An enlarged waveguide having a circular cross section into which a wave is introduced , wherein the enlarged waveguide inner wall surface of the enlarged waveguide has a different vertical / horizontal inner diameter ratio.
This is achieved by providing a ring-shaped partition plate in which holes are vertically arranged in a direction perpendicular to the long side of the rectangular waveguide section .

[0006]

According to the present invention, microwaves from a microwave generation source are guided to a space provided with a partition plate of an enlarged waveguide. In the enlarged space of the enlarged waveguide, a microwave resonance space is formed in the axial direction across the partition plate, and a strong electric field is generated inside the space of the enlarged waveguide, and the microwave of the strong electric field is generated. It is incident on the microwave introduction window. Thereby, strong plasma is generated in the plasma generation chamber. In addition, by optimizing the shape of the partition plate so as to have a ring shape having different vertical and horizontal inner diameter ratios, a uniform electric field is formed in the space of the enlarged waveguide, and uniform plasma is generated in the plasma generation chamber. As a result, the ashing speed of the workpiece and the in-plane uniformity of the ashing processing speed are improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a microwave plasma processing apparatus of the present invention. The plasma generation chamber is formed by being surrounded by the discharge block 10, the punching metal 12, and the microwave introduction window 9. As the microwave introduction window 9, a quartz plate (alumina or the like can be used in addition thereto) that can transmit a microwave and can form a plasma generation chamber is used. The punching metal 12 has a plurality of small diameter holes.
As described in JP-A-122123, the distance between the microwave introduction window 9 and the microwave introduction window 9 is set to 1/8 wavelength or more of the guide wavelength of the microwave. The discharge block 10 is provided with a processing gas supply port 11 connected to a processing gas supply device (not shown).

In a plasma processing chamber 13 communicating with a plasma generating chamber via a punching metal 12, a sample table 15 for disposing a wafer 14 to be processed is provided in parallel with the microwave introduction window 9. . The heater 16 is provided below the sample table 15 and indirectly heats the wafer 14. An exhaust device (not shown) is connected to a lower portion of the plasma processing chamber 13 to evacuate the plasma processing chamber 13 and the plasma generation chamber to a predetermined pressure.

[0009] An enlarged waveguide is connected to the plasma generation chamber through the microwave introduction window 9. The enlarged waveguide in this case comprises a waveguide 2, an isolator 3, a quadrature converter 4, a matching device 5, and waveguides 6 and 7. In this case, the magnetron 1 serving as a microwave generation source has a frequency of 2.45G.
Hz, and the rectangular waveguide 2 to which the magnetron 1 is attached has a standard size in which a microwave of TE10 mode can be transmitted in this case. Reference numeral 3 denotes an isolator for absorbing a reflected wave returning inside the rectangular waveguide 2. The right angle converter 4 converts the traveling direction of the microwave into a right angle. Reference numeral 5 denotes a stub-type matching unit that performs impedance matching of a load for eliminating reflection of a microwave transmitted through the rectangular waveguide 2.

The resonance chamber 17 which is an enlarged space of the enlarged waveguide
Is formed by waveguides 6 and 7 and a microwave introduction window 9, and a partition plate 8 for resonating microwaves is provided in the room.
Is provided. As shown in FIG. 2, the partition plate 8 is formed in a ring shape in which the hole shape is different between the vertical A and the horizontal B. The longer hole of the partition plate 8 is arranged so as to be orthogonal to the longer side of the rectangular shape of the waveguide 2.

A case where the above-structured apparatus is used as an ashing apparatus will be described. A wafer 14 for photoresist ashing is mounted on a sample table 15 maintained at a temperature of 200 ° C. by a heater 16 by a known transport technique, and O ₂ gas 1400 sc is supplied from a processing gas inlet 11.
cm, the pressure in the plasma generation chamber and the plasma processing chamber 13 was set to 133 pa, and microwaves were generated from the magnetron 1 for measurement. In this case, the diameter of the waveguide 7 is φ234 mm, the hole shape of the partition plate 8 is A = 140 mm, the width B = 200 mm, the interval between the partition plate 8 and the microwave introduction window 9 is 55 mm, and the waveguide 6 is partitioned from the waveguide 6. Ashing was performed by changing the interval 1 between the plates 8, and as shown in FIG. 3, when the interval 1 was set to 112 mm, a high ashing speed and good in-plane uniformity of the ashing speed were obtained.

FIG. 4 shows the ashing speed and the uniformity in the wafer at the time when the hole shape of the partition plate 8 is changed by the dimensional ratio of horizontal B / vertical A, and the dimensional ratio B / A is changed. , About 1.4, the ashing speed and the uniformity within the wafer were the best.

This is because the distance l between the waveguide 6 and the partition plate 8 is 1
It is considered that the combination of the resonance of 12 mm and the resonance of the space between the partition plate 8 and the microwave introduction window 9 strengthens the microwave electric field and increases the plasma generation efficiency. As a result, it is considered that the ashing speed was improved, and the uniformity of the ashing speed was improved by creating a uniform electric field distribution.

Further, the interval 1 was set to 112 mm, and the case where the punching metal 12 was installed and the case where it was not installed were compared. This is shown in FIG.

As described above, according to this embodiment, by providing a ring-shaped partition plate having holes with different aspect ratios in the enlarged space of the enlarged waveguide, the microwave in the enlarged waveguide has a strong electric field and is almost uniform. And a substantially uniform plasma having a high density can be generated in the plasma discharge chamber. Thereby, the ashing speed can be improved and the in-plane uniformity of the ashing speed can be improved.

In this embodiment, the case of ashing of a wafer has been described. However, the present invention is also applicable to a case of etching into a predetermined shape using plasma or a case of depositing on a wafer.

[0017]

According to the present invention, a strong electric field is generated by installing a partition plate in a waveguide, and active particles can be efficiently generated in a plasma generation chamber. There is an effect that the inner uniformity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a microwave plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a partition plate in the apparatus of FIG.

FIG. 3 is a diagram showing a relationship between a partition plate position and an ashing speed in the apparatus of FIG.

FIG. 4 is a diagram showing a relationship between the shape of a partition plate, an ashing speed, and an in-plane uniformity of an ashing processing speed in the apparatus of FIG.

FIG. 5 is a characteristic diagram showing a comparison of an ashing speed depending on whether or not a punching metal is installed in the apparatus of FIG. 1;

[Explanation of symbols]

1 ... magnetron, 6,7 ... waveguide, 8 ... partition plate, 9 ...
Microwave introduction window, 10: discharge block, 12: punching metal.

──────────────────────────────────────────────────続 き Continued on the front page (72) Katsuyoshi Kudo, Inventor Katsumatsu-shi, Yamaguchi Prefecture 794, Higashi-Toyoi, Hitachi Inside Kasado Engineering Co., Ltd. (56) References JP-A-5-283196 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05H 1/46 C23F 4/00 H01L 21/3065

Claims (1)

(57) [Claims] 1. A plasma generating chamber, means for supplying a processing gas to the plasma generating chamber, a processing chamber connected to one end of the plasma generating chamber via a punching metal, and means for evacuating the processing chamber If, transmitted via the closed and rectangular waveguide the enlarged space having a predetermined size are connected through the microwave introducing window to the connection portion of the plasma generation chamber to the other end of the plasma generation chamber Microwave introduced
Is the provided with an enlarged waveguide having a circular section, the expansion of the waveguide enlarged waveguide wall the aspect inside diameter ratio different Do Ri previous
A microwave plasma processing apparatus provided with a ring-shaped partition plate in which holes are vertically arranged so as to be perpendicular to the long side of the rectangular waveguide section .