JPS63221622A - Dry-type thin film processing equipment - Google Patents

Abstract

PURPOSE:To facilitate processing of a thin film highly efficiently by a method wherein one end surface of a plasma generating chamber which is coupled with a waveguide with a vacuum window between is so constructed as to be cooled with coolant and the heat created in the vacuum window by the transmission of microwave is led out to the end surface of the plasma generating chamber. CONSTITUTION:The end surface 3b of a plasma generating chamber 3 is so formed as to have a flat hollow ring shape and cooling water is supplied into the hollow part and drained out through a drain pipe 5e to keep the temperature of the top surface of the end surface 3b always low. A vacuum window has a double-window structure composed of two dielectric plates 2A and 2B. Even if the window 2A on the plasma generating chamber side is broken, a sudden application of atmospheric pressure load can be avoided and the leakage of the gas from the plasma generating chamber can be avoided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to dry etching using microwave plasma and chemical vapor vapor deposition (CVD).
This is a thin film processing device capable of forming a film by a reaction in which a gaseous substance reacts to deposit a solid on a substrate, and includes a means for generating microwaves, a waveguide for transmitting the microwaves, The waveguide is formed in a cylindrical shape and is connected to the waveguide at one end surface of the cylinder through a vacuum window made of a plate-like conductor, and the microwave is introduced through the vacuum window and is also connected to the waveguide through a gas supply means. An opening comprising an excitation solenoid that generates magnetic lines of force that generate a single active atom molecule or ion by turning the introduced gas into plasma due to the resonance effect with the microwave, and whose axis coincides with the central axis of the flux of magnetic lines of force generated by the solenoid. a plasma generation chamber having a plasma generation chamber on the other end surface, and the surface is etched by the active atom molecule or ion coupled to the plasma generation chamber through the opening and flowing out from the opening along the magnetic flux, or The present invention relates to a device comprising a processing chamber in which a substrate on which a thin film is to be formed is disposed, and an exhaust means for evacuating the plasma generation chamber and the processing chamber.

[Conventional technology]

In the technical field to which this invention pertains, process technology using ECR plasma has recently been attracting attention.11ECR is Electron Cyclotron Reaoa.
ancv (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 magnetic lines of force, and the condition where centrifugal force and Lorentz force are balanced is called the ECR condition. When the centrifugal force is expressed as srω and the Lorentz force is expressed as -qrωB, the condition for their balance is ω/B = q/m. Here, ω is the lunar velocity of the microwave, B is the magnetic flux density,
q/m is the specific charge of the electron. The microwave frequency generally used is 2) 45 GHz, which is approved for industrial use.
In that case, 0.0875T is the resonant magnetic flux density.

For example, a method shown in FIG. 2 is known as a thin film processing apparatus that applies ECR plasma. In this device, plasma generation chamber 3. The processing chamber 9 is evacuated by an evacuation means (not shown), and the raw material gas introduction pipe 4 is used as a gas supply means.
From there, the gas was flowed into the plasma generation chamber 3, where the microwave was transferred to the waveguide 1, which was a means of transmitting the microwave, and the waveguide side, which was made of a plate-shaped dielectric material and was under atmospheric pressure, was evacuated. The plasma generation chamber 3 is fed into the plasma generation chamber via a vacuum window 2 for airtightly isolating the inside of the plasma generation chamber 3.
A metal plate 17 with a large-diameter hole 7 in the center is attached to the lower part of the plasma generating chamber 3, and this metal plate and the plasma generation chamber 3 constitute a semi-open microwave resonator. An excitation solenoid 6 is disposed outside the resonator, and a magnetic field that satisfies the ECR conditions is generated within the resonator, so that ECR plasma is generated within the resonator. This plasma
When silane gas (SiH*) is pushed inward and directed from the gas population 12 into the space toward the sample stage 10 and activated by the plasma, the generated active species react with the substrate 11, which is the sample to be processed. A thin film is formed on the surface of the substrate.

Note that this apparatus can be used for etching a substrate by flowing an etching gas instead of the N-rich gas from the raw material gas introduction pipe 4. Note that 5 is a cooling cylinder that cools the outer peripheral surface of the plasma generation chamber 3. Further, 16 is an OIJ song, which is inserted into a packing groove provided in a flange 1a fixed to the end of the -4 wave tube in order to connect the waveguide 1 to the plasma generation chamber 3, and connects the plasma generation chamber 3 and the outside air. It is airtightly sealed off. This flange la
A vacuum window 2 made of a plate-shaped dielectric and a ring plate-shaped packing 15 are housed inside the flange la.
6 is compressed and tightened onto the end surface 3a of the plasma generation chamber 3, thereby airtightly sealing off the plasma generation chamber 3 and the inside of the waveguide l. In this case, the ring plate-shaped 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 O-ring and the plasma Airtightness between the generation chamber and the inside of the waveguide is achieved by a gasket 15, and these two gaskets each serve as an airtight portion.

[Problem 1 to be solved by the invention Problems in the dry 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 commonly used as I), which is not easily attacked by etching gas plasma.
II: using the word alumina), but when high-power microwaves pass through this window, heat is generated due to impurities contained in the alumina, and the window is distorted due to this heat. There is a risk of destruction. If the window breaks, air in the waveguide will flow into the plasma generation chamber and processing chamber, rapidly increasing the load on the vacuum pumping system, which is not only harmful, but also harmful to the human body, which is used for thin film processing. There is also the possibility of gas leaking out, which is extremely dangerous. Furthermore, when the substrate is heated with a heater for epitaxial growth film formation, oxidation, etc., the vacuum window 2 and the end surface 3a of the plasma generation chamber are heated by the heat from the heater, and the plasma is introduced into the plasma generation chamber. Even when the microwave power is small, for example, less than 1 kW, the vacuum window may be broken or components such as the O-ring 16 may be damaged, which may impede stable operation of the apparatus.

The purpose of the present invention is to enable high-efficiency thin film processing by introducing high-power microwaves into a plasma generation chamber without destroying the vacuum window, and to avoid any hindrance even if the equipment is heated by a heater for heating the substrate. The object of the present invention is to provide a dry thin film processing device that can be operated without any problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides means for generating microwaves, a waveguide for transmitting the microwaves, and a cylindrical-shaped waveguide. A wave tube and a vacuum window made of a plate-shaped dielectric material are connected at one end face of the tube, and microwaves are introduced through the vacuum window, and the gas fed through the gas supply means is Equipped with an excitation solenoid that generates magnetic lines of force that turn into plasma and produce nine active atoms molecules or ions due to the resonance effect with microwaves, and has an opening on the other end surface whose axis coincides with the central axis of the flux of magnetic lines of force generated by the solenoid. a plasma generation chamber; and a substrate whose surface is etched or a thin film is formed by the active atom molecule or ions that are coupled to the plasma generation chamber through the opening and flow out from the opening along the magnetic flux. A dry thin film processing apparatus equipped with a processing chamber in which a plasma generating chamber is disposed, and an exhaust means for evacuating the plasma generating chamber and the processing chamber is connected to one side of the plasma generating chamber connected to the waveguide through the vacuum window. The end face of the vacuum window is configured to be coolable using a refrigerant, and the heat generated by the vacuum window based on the passage of the microwave is interposed between the vacuum window and the end face of the plasma generation chamber and/or between the waveguide. The waveguide is configured to be guided to the end face of the plasma generation chamber to be cooled via an elastic sheet that airtightly connects the waveguide and the plasma generation chamber.

[Effect]

By configuring the device in this way, the end face of the plasma generation chamber can be maintained at a much lower temperature than before, so the heat generated by the vacuum window due to the passage of microwaves is effectively led out through the elastic sheet, and the temperature of the vacuum window is reduced. In addition to suppressing temperature rise, it also prevents heat damage to components such as O-rings that come into contact with the end face of the plasma generation chamber, making it possible to introduce high-power microwaves into the plasma generation chamber, and also for substrate heating. It also becomes possible to operate a device using a heater.

〔Example〕

FIG. 1 shows an embodiment of a dry thin film processing apparatus constructed based on the present invention. After being fed into the bottom of the cooling cylinder 5 from the water pipe 5a, it 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. Cooling water is fed in, and the fed cooling water is led out to the outside via the drain pipe 5e. Thereby, the upper surface of the end surface 3b is always kept at a low temperature. On the other hand, vacuum windows
In this example, the window 2A on the plasma generation chamber side, which is formed in a double window structure consisting of two plate-shaped dielectrics 2A and -2B, which is subjected to severer thermal stress, breaks and the window 2A on the waveguide side Even if the airtight performance between the plasma generation chamber side and the plasma generation chamber side is lost, the presence of the vacuum window 2B ensures that there is a slow leak between the waveguide side and the plasma generation chamber side, and the evacuation system On the other hand, it is necessary to prevent sudden atmospheric pressure loads, prevent gases harmful to the human body from escaping from the plasma generation chamber, and prevent the risk of ignition that could occur if this gas were to escape. However, this means that after the vacuum window 2 is destroyed, the microwave generation is stopped to stop the operation of the device.
This is to ensure that there is enough time to stop various parts, such as stopping the supply of raw material gas, stopping the energization of the excitation solenoid, and stopping the operation of the vacuum exhaust system, to facilitate a smooth transition to repair of the equipment. As long as the configuration is as follows, there is still a risk of destruction of the vacuum window 2A. However, as in this embodiment, if the end face is formed into a flat hollow ring shape as shown in 3b, and cooling water is introduced into this hollow part for cooling, the vacuum window 2
The heat generated at A is transferred to the end W3b via the elastic sheath) 21b.
Since the heat generated in the vacuum window 2B is also led out to the top surface of the end face 3b via the flange 21a, the temperature of both vacuum windows is always kept relatively low, and the temperature of the vacuum window 2B is effectively led out to the top surface. Does not cause thermal distortion that would lead to destruction.

By the way, the elastic sheet 21b interposed between the vacuum window 2A and the end surface 3b has the role of effectively guiding the heat generated by the vacuum window to the end surface of the plasma generation chamber, which is maintained at a low temperature by cooling water. Therefore, the better the thermal conductivity is used, the greater the effect will be. If airtightness is achieved between the outside air and the inside of the waveguide in one place, the conventional O-ring (Fig. 2, 16) and the waveguide side seal (Fig. 2, 1) will be used.
5) can be omitted at the same time. Of course, even if a thermally conductive sheet is interposed between the vacuum window and the waveguide as in the conventional case, the flange 21a and the end face of the plasma generation chamber are connected in a state of metal contact. The heat generated is effectively led to the end face of the plasma generation chamber via the flange 21a, and the temperature rise is suppressed similarly to the vacuum window 2A.

For this reason, the material used for the elastic sheet is, for example, a powdered material called boron nitride, which has good thermal conductivity, and is mixed into an elastic material with good heat resistance, such as silicone rubber, to form a sheet. . In this way, the elastic sheet itself is kept at a relatively low temperature, and combined with its heat resistance, it becomes possible to operate the elastic sheet while maintaining airtight elasticity with a margin. Note that when the vacuum window has a double-glazed 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 thermally conductive sheet 21h to simplify the device. It is also possible to improve the

〔Effect of the invention〕

As described above, according to the present invention, the end face of the cylindrical plasma generation chamber, which is connected to the waveguide through the vacuum window, is configured to be coolable using a refrigerant. As a result, the heat generated by the vacuum window due to the passage of microwaves is effectively led to the end face of the plasma generation chamber through the elastic sheet, and the temperature rise of the vacuum window is suppressed. Vacuum windows are kept relatively cool,
High-power microwaves can be introduced into the plasma generation chamber without destroying the vacuum window, making it possible to perform highly efficient film formation. Damage to device components such as the ring can be avoided, allowing stable operation of the device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a device showing an example of a conventional device. 1.21: Waveguide, 2.2A, 28: Vacuum window, 3: Plasma generation chamber, 4: Gas supply means, 5: Cooling cylinder, 5a:
Water pipe, 5b, 5e: Drain pipe, 6: Excitation solenoid, 7
: opening, 9: processing chamber, 11: substrate, 21b? elastic sheet. Lou Guan Scarlet Fruit! air exhaust system

Claims (1)

[Claims] 1) A means for generating microwaves, a waveguide for transmitting the microwaves, and a vacuum window formed in a cylindrical shape and made of the waveguide and a plate-shaped conductor. Microwaves are introduced through the vacuum window connected at one end face of the cylinder, and the gas fed through the gas supply means is turned into plasma by the resonance effect with the microwave to generate active atoms, molecules, or a plasma generation chamber including an excitation solenoid that generates magnetic lines of force that generate ions, and having an opening on the other end surface whose axis coincides with the central axis of the magnetic line of force generated by the solenoid;
A process in which a substrate is arranged, the surface of which is etched or a thin film is formed by the active atoms, molecules or ions that are coupled to the plasma generation chamber through the opening and flow out from the opening along the magnetic flux. In a dry thin film processing apparatus comprising a chamber and an exhaust means for evacuating the plasma generation chamber and the processing chamber, one end surface of the plasma generation chamber connected to the waveguide through the vacuum window is configured to discharge a coolant. The heat generated by the vacuum window based on the passage of the microwave 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 plasma. A dry thin film processing apparatus characterized in that the plasma is led out to the end face of the plasma generation chamber to be cooled through an elastic sheet that airtightly connects the plasma generation chamber with the generation chamber. 2) In the device according to claim 1, the elastic sheet interposed between the vacuum window and the end face of the plasma generation chamber and/or between the waveguide is a thermally conductive sheet with good thermal conductivity. A dry thin film processing device characterized by the following.