JPH07272897A - Microwave plasma equipment - Google Patents

Abstract

(57) [Summary] [Microwave introduction plate 25 is composed of a metal plate 26 having a plurality of holes 26a and a plurality of dielectrics 27 inserted and adhered to the plurality of holes 26a. Wave plasma equipment. [Effect] The inside of the reactor 11 can be kept airtight, and an electric field can be uniformly formed in the reactor 11 through the plurality of dielectrics 27. Further, since the main part of the microwave introducing plate 25 is composed of the metal plate 26,
The resistance to thermal stress and mechanical stress can be increased as a whole, and the elastic adhesive 28 can absorb the difference in thermal expansion between the dielectric 27 and the metal plate 26. Therefore, plasma can be uniformly generated in the reactor 11, and damage to the microwave introducing plate 25 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma device, and more particularly, it utilizes plasma generated by introducing microwaves to etch, ash, or form thin films on, for example, semiconductor element substrates. The present invention relates to a microwave plasma device used as a device for applying the above.

[0002]

2. Description of the Related Art FIG. 3 is a schematic cross-sectional view of a conventional microwave plasma apparatus. In FIG. 3, reference numeral 11 shows a reactor formed of a metal such as aluminum into a substantially hollow rectangular parallelepiped shape. There is. A plasma chamber 12 and a reaction chamber 13 are formed in the reactor 11, and the plasma chamber 12 and the reaction chamber 1 are formed.
3 is separated by a shower head 14 having a plurality of holes 14a. Shower head 1 in reaction chamber 13
4 is a sample table 1 for mounting the sample S at a position facing 4
5 is provided, an exhaust port 16 connected to an exhaust device (not shown) is formed in the lower wall of the reaction chamber 13, and a required reaction in the reactor 11 is provided on one side wall of the plasma chamber 12. A gas supply pipe 17 for supplying gas is connected. A microwave introducing plate 30 is arranged above the reactor 11, and the microwave introducing plate 30 is made of a ceramic material having excellent microwave permeability and small dielectric loss. Further, as shown in FIG. 4, the microwave introducing plate 30 has a length L of about 380 mm and a width W of about 380 m.
m and the thickness t are formed in a plate shape of about 20 mm. The end of the microwave introducing plate 30 and the upper part of the reactor 11 are in close contact with each other, and the inside of the reactor 11 is hermetically sealed by the microwave introducing plate 30.

On the other hand, a dielectric line 18 made of fluororesin, polyethylene, polystyrene or the like having a small dielectric loss is disposed above the reactor 11 at a position facing the microwave introducing plate 30. Top 1 of 18
A lid 19 is arranged on the side 8a and the side surface 18b so as to cover them, and the lid 19 is formed by using a metal plate such as aluminum. Further, a microwave oscillator 22 is connected to the dielectric line 18 via a waveguide 21, and the microwave oscillated from the microwave oscillator 22 is introduced into the dielectric line 18.

When performing the ashing process of the resist applied to the surface of the sample S mounted on the sample table 15 by using the microwave plasma device configured as described above, first, the exhaust device is driven to exhaust gas. After exhausting gas from the port 16 and setting the inside of the reactor 11 to a required degree of vacuum, a required reaction gas is supplied to the plasma chamber 12 through the gas supply pipe 17. Next, a microwave is oscillated from the microwave oscillator 22 and this microwave is introduced into the dielectric line 18. Then, an electric field is formed below the dielectric line 18, the formed electric field is transmitted through the microwave introduction plate 30 and is supplied to the plasma chamber 12 to generate plasma. The charged particles in the generated plasma are captured by the shower head 14, and mainly neutral particles such as radicals are showered by the shower head 1.
After passing through the hole 14a of No. 4 and guided to the periphery of the sample table 15 in the reaction chamber 13, the resist on the sample S is ashed.

[0005]

In the above-mentioned microwave plasma apparatus, the temperature in the vicinity of the central portion 30a of the microwave introducing plate 30 rises to about 180 ° C. while performing the plasma treatment, while the microwave introducing plate 30 Since the heat is easily radiated through the upper wall of the reactor 11 in the vicinity of the peripheral end portion 30b, the temperature thereof is hard to rise. As a result, the temperature distribution inside the microwave introducing plate 30 becomes non-uniform, and thermal stress is generated. In addition, the peripheral end portion 30 of the microwave introduction plate 30
b is constrained by the upper wall of the reactor 11, and mechanical stress acts on the microwave introducing plate 30 from the upper wall of the reactor 11. Due to the complicated interaction between the thermal stress and the mechanical stress, there is a problem that the microwave introduction plate 30 is likely to be damaged in the vicinity of the ridge line portion 32 where the strength is relatively weak or in the portion to which the repeated bending stress is applied.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a microwave plasma device capable of preventing the microwave introduction plate from being damaged.

[0007]

In order to achieve the above-mentioned object, a microwave plasma device according to the present invention comprises a microwave oscillator, a dielectric line for propagating microwaves, and a dielectric line which is opposed to the dielectric line. In a microwave plasma device provided with a reactor having a microwave introducing plate, the microwave introducing plate includes a metal plate having a plurality of holes, and a plurality of dielectrics inserted and adhered to the plurality of holes. It is characterized by being composed of.

[0008]

According to the microwave plasma device having the above structure,
Since the microwave introduction plate is composed of a metal plate having a plurality of holes and a plurality of dielectrics inserted and adhered to the plurality of holes, the inside of the reactor can be kept airtight, An electric field can be uniformly formed in the reactor through the plurality of dielectrics. Further, since the main part of the microwave introducing plate is composed of the metal plate, it is possible to increase the resistance to thermal stress and mechanical stress as a whole, and at the same time, with the elastic adhesive, the dielectric and the dielectric The difference in thermal expansion with the metal plate can be absorbed.
Therefore, plasma can be uniformly generated in the reactor and damage to the microwave introduction plate can be prevented.

[0009]

EXAMPLES AND COMPARATIVE EXAMPLES Examples of a microwave plasma apparatus according to the present invention will be described below with reference to the drawings. In addition,
Components having the same functions as those of the conventional example are designated by the same reference numerals. 1 is a sectional view schematically showing an embodiment of a microwave plasma device according to the present invention, and its configuration is the same as that of the microwave plasma device shown in FIG. 3 except for a microwave introducing plate 25. Therefore, a detailed description of the overall configuration will be omitted here, and the configuration will be described mainly for the portion related to the microwave introduction plate 25. In the figure, 26 indicates a metal plate, and the metal plate 26 has a length L of about 380 m.
m, the width W is about 380 mm, and the thickness t is about 20 mm (FIG. 2), and a plurality of holes 26a having a substantially inverted convex cross-section are formed at predetermined positions of the metal plate 26. Has been formed. Dielectrics 27 are inserted and fixed in the plurality of holes 26a with a gap 28a.
7 is made of alumina (Al ₂ O ₃ ) and its longitudinal section is formed into a substantially inverted convex shape, and an adhesive holding groove 27a is formed at a predetermined position of the dielectric 27. As shown in FIG. 2, the metal plate 26 and the dielectric 27 are adhered to each other in an airtight state using an adhesive 28 such as a ceramic bond, and the microwave including the metal plate 26 and the dielectric 27 is included. Introductory plate 25
Is configured. Further, the end of the microwave introducing plate 25 and the upper part of the reactor 11 are in close contact with each other, and the microwave introducing plate 2
The inside of the reactor 11 is hermetically sealed by 5.

When performing the ashing process of the resist applied on the surface of the sample S mounted on the sample table 15 using the microwave plasma device thus configured, first, the exhaust device is driven to exhaust the gas. After exhausting gas from the port 16 and setting the inside of the reactor 11 to a required degree of vacuum, a required reaction gas is supplied to the plasma chamber 12 through the gas supply pipe 17. Next, a microwave is oscillated from the microwave oscillator 22 and this microwave is introduced into the dielectric line 18. Then, an electric field is formed below the dielectric line 18, and the formed electric field passes through the plurality of dielectrics 27 in the microwave introduction plate 25 and is supplied to the plasma chamber 12 to generate plasma. The charged particles in the generated plasma are captured by the showerhead 14, and mainly only neutral particles such as radicals pass through the holes 14a of the showerhead 14 and are guided to the periphery of the sample table 15 in the reaction chamber 13, where the sample S Ashes the upper resist.

The results of investigating the damage state of the microwave introducing plate 25 by repeatedly performing the plasma treatment using the microwave plasma apparatus shown in FIG. 1 will be described below. As the measurement conditions, 950 sccm of oxygen gas and 50 sccm of nitrogen gas were introduced from the gas supply pipe 17, the pressure in the reaction chamber 13 was 1 Torr, and the microwave power was 1.5.
The plasma treatment in which kW was set and plasma was generated for 10 minutes and stopped for 1.5 minutes was repeated. As the microwave introduction plate 25, a plate provided with nine dielectrics 27 was used. As a comparative example, the conventional microwave plasma device shown in FIG. 3 was used.

The results are shown in Table 1 below. In the conventional microwave plasma device, the microwave plasma plate was damaged at most 29 times, but in the microwave plasma device according to the example, the microwave introduction plate 25 was not damaged even after repeating the plasma process 100 times or more.

[0013]

[Table 1]

As is clear from this result, in the microwave plasma device according to the embodiment, the microwave introducing plate 25 is used.
Is a metal plate 26 having a plurality of holes 26a and a plurality of holes 2
Since it is composed of a plurality of dielectrics 27 that are inserted and adhered to 6a, the inside of the reactor 11 can be maintained in an airtight state, and an electric field can be generated inside the reactor 11 through the plurality of dielectrics 27. It can be formed uniformly. Also,
Since the main part of the microwave introducing plate 25 is composed of the metal plate 26, it is possible to enhance the resistance to thermal stress and mechanical stress as a whole, and at the same time, the elastic adhesive 28 allows the dielectric 27 and the metal. The difference in thermal expansion with the plate 26 can be absorbed. Therefore, plasma can be uniformly generated in the reactor 11, and damage to the microwave introducing plate 25 can be prevented.

In this embodiment, the metal plate 26 in which nine dielectrics 27 are inserted and adhered is used, but the number of dielectrics 27 is not limited to nine.

In this embodiment, the dielectric 27 is made of Al ₂ O.
_{Although 3} is used, Si ₃ N ₄ or quartz may be used in another embodiment.

Further, although the case where the sample S is subjected to the ashing treatment has been described in the present embodiment, the same effect can be obtained when the etching treatment, the thin film forming treatment and the like are performed.

[0018]

As described above in detail, in the microwave plasma device according to the present invention, the microwave introducing plate is a metal plate having a plurality of holes, and a plurality of microwave introducing plates are inserted and adhered to the plurality of holes. Since it is composed of individual dielectrics, the inside of the reactor can be kept airtight, and an electric field can be uniformly formed in the reactor through the plurality of dielectrics. Further, since the main part of the microwave introducing plate is composed of the metal plate, it is possible to increase the resistance to thermal stress and mechanical stress as a whole, and at the same time, the dielectric with the adhesive having elasticity. And the difference in thermal expansion between the metal plate and the metal plate can be absorbed. Therefore, plasma can be uniformly generated in the reactor and damage to the microwave introduction plate can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a microwave plasma device according to the present invention.

2A and 2B are diagrams showing a microwave introducing plate of a microwave plasma device according to an embodiment, FIG. 2A is a plan view, and FIG.
Shows a sectional view taken along line AA in (a).

FIG. 3 is a schematic cross-sectional view of a conventional microwave plasma device.

FIG. 4 is a schematic view showing the shape and dimensions of a microwave introduction plate in a conventional microwave plasma device,
(A) is a plan view and (b) is a front view.

[Explanation of symbols]

 11 Reactor 18 Dielectric Line 22 Microwave Oscillator 25 Microwave Introducing Plate 26 Metal Plate 26a Hole 27 Dielectric 28 Adhesive

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/3065

Claims (1)

[Claims] 1. A microwave plasma device comprising a microwave oscillator, a dielectric line for propagating microwaves, and a reactor having a microwave introducing plate arranged to face the dielectric line, wherein the microwave plasma device comprises: A microwave plasma apparatus, wherein the introduction plate is composed of a metal plate having a plurality of holes and a plurality of dielectrics inserted and adhered to the plurality of holes.