JPH0620058B2 - Dry thin film processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to dry etching and CVD (Chemical Vapor Deposition,
A thin film processing apparatus capable of forming a film by a reaction in which a gaseous substance reacts to deposit a solid on a substrate, a means for generating a microwave, and a waveguide for transmitting the microwave,
It is coupled at one end face of the tube through a vacuum window formed in a tubular shape and made of a plate-shaped conductor, and microwaves are introduced through the vacuum window and at the same time through a gas supply means. An opening provided with an exciting solenoid for generating a magnetic field line for generating an active atom, molecule or ion by plasmaizing the introduced gas by a resonance effect with the microwave, and an axis line of which coincides with a central axis of a magnetic flux line generated by the solenoid. A plasma generating chamber having the other end face, and the surface is etched by the active atoms, molecules or ions that are coupled to the plasma generating chamber through the opening and flow out from the opening along the magnetic flux. The present invention relates to an apparatus including a processing chamber in which a substrate on which a thin film is formed is arranged, and an exhaust unit for exhausting the plasma generation chamber and the processing chamber.

[Conventional technology]

In the technical field to which the present invention belongs, a process technology using ECR plasma has recently attracted attention. What is ECR
Abbreviation for Electron Cyclotron Resonance, which accelerates electrons using the resonance effect of a magnetic field and microwaves, and uses the kinetic energy of the electrons to ionize gas to obtain plasma. Electrons excited by microwaves move circularly around the lines of magnetic force, and at that time, the condition under which the centrifugal force and the Lorentz force are balanced is EC.
Called the R condition. Centrifugal force is mrω ² and Lorentz force is −q
When expressed by rωB, the condition for balancing these is ω / B
= Q / m. Here, ω is the angular velocity of the microwave, B is the magnetic flux density, and q / m is the specific charge of the electron. Microwave frequency 2.45 GHz _z is generally used as permitted for industrial, in which case 0.0875T is resonance magnetic flux density.

As a thin film processing apparatus to which ECR plasma is applied, for example, the method shown in FIG. 2 is known. In this apparatus, the plasma generation chamber 3 and the processing chamber 9 are evacuated by an unillustrated evacuation means, and the raw material gas introduction pipe line 4 as a gas supply means is used.
To the place where the N ₂ gas was made to flow into the plasma generation chamber 3, the microwave was evacuated to the waveguide 1 which is a means for transmitting the microwave and the waveguide side which is made of a plate-shaped dielectric and is under atmospheric pressure. It is sent to the plasma generation chamber through a vacuum window 2 for hermetically isolating the inside of the plasma generation chamber 3. A metal plate 17 having a large-diameter hole 7 in the center is attached to the lower part of the plasma generation chamber 3, and the metal plate and the plasma generation chamber 3 form a semi-open microwave resonator. An exciting solenoid 6 is arranged outside the resonator, and an ECR is provided inside the resonator.
Since a magnetic field that satisfies the conditions is generated, EC is
R plasma is generated. When this plasma is pushed out into the processing chamber 9 and silane gas (SiH ₄ ) is sent from the gas inlet 12 into the space toward the sample table 10 and this gas is activated by the plasma, the generated active species generate the processed sample. Reacts with the substrate 11 to form a thin film on the substrate surface.

By flowing the etching gas instead of the N ₂ gas from the raw material gas introduction conduit 4, this apparatus can be used for etching the substrate. Reference numeral 5 is a cooling cylinder for cooling the outer peripheral surface of the plasma generation chamber 3. Also,
Reference numeral 16 denotes an O-ring, which is inserted into a packing groove provided in a flange 1a fixed to the end of the waveguide for coupling the waveguide 1 to the plasma generation chamber 3 and connects the plasma generation chamber 3 and the outside air. It shuts off airtightly. A vacuum window 2 made of a plate-shaped dielectric and a ring-plate packing 15 are housed inside the flange 1a, and the flange 1a is clamped to the end face 3a of the plasma generation chamber 3 while compressing the O-ring 16, so that the plasma is generated. The generation chamber 3 and the inside of the waveguide 1 are hermetically isolated from each other.
In this case, the ring-plate packing 15 is inserted on the waveguide side of the vacuum window in order to reduce the thermal influence from the plasma generation chamber, and the plasma generation chamber and the outside air are hermetically sealed by the O-ring and the plasma. Airtightness between the generation chamber and the inside of the waveguide is performed by the packing 15, and the airtight parts are shared by both packings.

[Problems to be solved by the invention]

The problems with the dry type thin film processing apparatus configured as described above are as follows. That is, the vacuum window 2 interposed between the waveguide and the plasma generation chamber is usually made of aluminum oxide (hereinafter referred to as idiom:
It is produced as a plate (using the term alumina), but when high-power microwaves pass through this window, heat is generated due to the impurities contained in the alumina, and the window is destroyed due to this heat distortion. There is danger. When the window breaks, the air in the waveguide flows into the plasma generation chamber and the processing chamber, and the load for exhausting against the vacuum exhaust system suddenly increases, which is not only harmful, but also harmful to the human body used for thin film processing. The outflow of various gases is also considered and is extremely dangerous. Furthermore, when the substrate is heated by a heater for film formation or oxidation by epitaxial growth, the heat from this heater heats the vacuum window 2 and the end surface 3a of the plasma generation chamber, and attempts to introduce the vacuum window 2 into the plasma generation chamber. Even when the microwave power is a small power less than 1 kW, for example, the vacuum window is broken or the components such as the O-ring 16 are damaged, which hinders stable operation of the device.

An object of the present invention is to introduce a high-power microwave into the plasma generation chamber without breaking the vacuum window to enable highly efficient thin film processing, and to prevent problems even when the apparatus is heated by the substrate heating heater. It is to provide a dry-type thin film processing apparatus that can be operated without any operation.

[Means for solving problems]

In order to achieve the above object, according to the present invention, means for generating a microwave, a waveguide for transmitting the microwave, and the waveguide formed in a tubular shape and a plate-shaped dielectric body are provided. The gas coupled through one end face of the cylinder through the vacuum window and introduced with the microwave through the vacuum window and the gas introduced through the gas supply means are turned into plasma by the resonance effect with the microwave. A plasma generating chamber having an exciting solenoid for generating magnetic lines of force that generate active atoms, molecules or ions, and having an opening at the other end face whose axis coincides with the central axis of the magnetic flux of the magnetic flux generated by the solenoid; A substrate on which a surface is etched or a thin film is formed by the active atoms, molecules or ions that are coupled to the plasma generation chamber and flow out from the opening along the magnetic flux A dry type thin film processing apparatus comprising a processing chamber and an exhaust means for exhausting the plasma generating chamber and the processing chamber, wherein one end surface of the plasma generating chamber coupled to the waveguide through the vacuum window is a refrigerant. And heat generation of the vacuum window based on the microwave passage, which is configured to be cooled by using a waveguide and a waveguide interposed between the vacuum window and the end face of the plasma generation chamber and / or the waveguide. It is configured to be led out to the end surface of the cooled plasma generation chamber through an elastic sheet that hermetically couples with the plasma generation chamber.

[Action]

By configuring the apparatus in this way, the end surface of the plasma generation chamber can be maintained at a much lower temperature than before, so that heat generation in the vacuum window due to microwave passage is effectively derived through the elastic sheet, and the vacuum window As the temperature rise is suppressed and damage to the components such as the O-ring that is in contact with the end face of the plasma generation chamber due to heat is prevented, high-power microwaves can be introduced into the plasma generation chamber and also for substrate heating. It is also possible to operate the device using the heater.

〔Example〕

FIG. 1 shows an embodiment of a dry type thin film processing apparatus constructed according to the present invention. The end surface 3b of the plasma generation chamber 3 coupled to the waveguide 1 is formed in a flat hollow ring shape, and after being fed from the water pipe 5a to the bottom of the cooling cylinder 5 into this hollow portion,
Cooling water that passes through a plurality of through holes 5d provided in the ring-shaped partition plate 5c and rises along the outer peripheral surface of the plasma generation chamber 3 is sent, and the sent cooling water is discharged through the drain pipe 5e. Outsourced. As a result, the upper surface of the end surface 3b is always kept at a low temperature. On the other hand, in the present embodiment, the vacuum window is formed in a double window structure composed of two plate-shaped dielectrics 2A and 2B, and the window 2A on the plasma generation chamber side, which is subjected to severe stress due to heat, is destroyed. Even if the airtight performance between the waveguide side and the plasma generation chamber side is lost, the existence of the vacuum window 2B causes a slow leak state between the waveguide side and the plasma generation chamber side. The vacuum exhaust system is prevented from being suddenly subjected to atmospheric pressure load, the outflow of gas harmful to the human body from the plasma generation chamber is prevented, and the ignition that may occur when this gas is outflowed. Although it prevents danger, this is because after the vacuum window 2A is broken, the microwave generation to stop the operation of the equipment is stopped, the supply of the raw material gas is stopped, the excitation solenoid is de-energized, and the vacuum exhaust system is stopped. Make sure that you have enough time to stop each part to repair the equipment. And in order to facilitate a row, the plasma generating chamber end face the risk of destruction of the vacuum window 2A as long as the conventional configuration still present. However, as in the present embodiment, if the end surface is formed into a flat hollow ring shape like 3b and cooling water is introduced into this hollow portion to cool, the heat generated in the vacuum window 2A is elastic sheet 21.
Since the heat generated in the vacuum window 2B is also effectively discharged to the upper surface of the end face 3b via b, and is also discharged to the upper surface of the end face 3b via the flange 21a, the temperature of both vacuum windows is always relatively low. The thermal strain is not generated so that the vacuum window is broken.

By the way, the elastic sheet 21b interposed between the vacuum window 2A and the end surface 3b has a role of effectively guiding the heat generation of the vacuum window to the end surface of the plasma generation chamber kept at a low temperature by the cooling water. Therefore, the one having a good thermal conductivity has a greater effect. Then, as in the embodiment, by interposing between the vacuum window and the end face of the plasma generation chamber so as to perform airtightness between the plasma generation chamber and the outside air and the inside of the waveguide at one location, The O-ring (Fig. 2, 16) and the waveguide side packing (Fig. 2, 15) can be omitted at the same time. Of course, even if a heat conductive sheet is conventionally interposed between the vacuum window and the waveguide, the flange 21
Since a and the plasma generation chamber end face are connected in a metal contact state, the heat generation of the vacuum window 2B is effectively led to the end face of the plasma generation chamber via the flange 21a, and the temperature rises like the vacuum window 2A. Can be suppressed.

For this reason, as the elastic sheet, for example, a powdery material called boron nitride having good heat conductivity is mixed with an elastic material having good heat resistance, for example, silicon rubber to form a sheet. . In this way, the elastic sheet itself is also kept at a relatively low temperature, and in combination with its heat resistance, it is possible to operate with a margin to maintain airtight elasticity. When the vacuum window has a double window structure as in this embodiment, the heat-resistant ring 21C interposed between the vacuum windows 2A and 2B is made of the same material as the heat conductive sheet 21b to simplify the apparatus. It is also possible to change.

〔The invention's effect〕

As described above, according to the present invention, since the cylindrical plasma generation chamber end face coupled to the waveguide through the vacuum window can be cooled by using the refrigerant, the plasma generation chamber end face is The temperature of the vacuum window is maintained at a significantly lower temperature as compared with the above, and as a result, the heat generated in the vacuum window due to the passage of microwaves is effectively guided to the end face of the plasma generation chamber through the elastic sheet, and the temperature rise of the vacuum window is suppressed. The vacuum window is kept relatively cool,
Since high-power microwaves can be introduced into the plasma generation chamber without destroying the vacuum window, highly efficient film forming processing is possible, and the vacuum window and O It is possible to avoid damage to the components of the device such as the ring and to operate the device stably.

[Brief description of drawings]

FIG. 1 is a device configuration diagram according to an embodiment of the present invention, and FIG. 2 is an device configuration diagram showing an example of a conventional device. 1, 21: Waveguide, 2, 2A, 2B: Vacuum window, 3: Plasma generation chamber, 4: Gas supply means, 5: Cooling cylinder, 5a: Water pipe, 5
b, 5e: drain pipe, 6: exciting solenoid, 7: opening, 9:
Processing chamber, 11: substrate, 21b: elastic sheet.

Claims (2)

[Claims] 1. A means for generating a microwave, a waveguide for transmitting the microwave, and one of the cylinders through a vacuum window formed in a cylinder and comprising the waveguide and a plate-shaped conductor. Of the active atoms, which are coupled at the end faces of the microwaves to introduce the microwaves through the vacuum window and the gas introduced through the gas supply means into plasma due to the resonance effect with the microwaves,
A plasma generating chamber having an exciting solenoid for generating magnetic force lines that generate molecules or ions, and having an opening at the other end face whose axis coincides with the central axis of the magnetic force flux generated by the solenoid; and the plasma generating chamber through the opening. A processing chamber in which a substrate, which is bonded and flows out from the opening along the magnetic flux, is subjected to surface etching or a thin film is formed by the active atoms, molecules or ions, the plasma generation chamber and the processing chamber In a dry thin film processing apparatus having an exhausting means for exhausting the exhaust gas, the one end surface of the plasma generation chamber coupled to the waveguide through the vacuum window is configured to be cooled by using a refrigerant, and The heat generated in the vacuum window due to the passage of microwaves is interposed between the vacuum window and the end face of the plasma generation chamber and / or between the waveguide and the waveguide and the plug. Dry film processing apparatus is characterized in that so as to be led to said cooled by the plasma generation chamber end surface and Ma generation chamber via an elastic sheet allowed to bind tightly. 2. The apparatus according to claim 1, wherein the elastic sheet interposed between the vacuum window and the end face of the plasma generating chamber and / or the waveguide has a heat conductivity of good heat conductivity. A dry thin film processing device characterized by being a conductive sheet.