JP4686668B2 - Plasma processing method and apparatus - Google Patents

Description

The present invention relates to a plasma processing method and apparatus for using plasma in the manufacture of semiconductor elements, the fine processing of polymer materials and insulating materials, and the like.

  Conventionally, dry etching, which is used to process fine grooves on the surface of a substrate such as silicon in a semiconductor device manufacturing process, exhausts air in a vacuum vessel with a vacuum pump, and halogen gas or the like in the vacuum vessel. The reactive gas is introduced, and the plasma is generated by applying a microwave or a high-frequency current under a predetermined pressure. By the physicochemical action of ions or radicals (neutral excited gas species) in the plasma The substrate surface is selectively etched.

  In addition, a sputtering film forming technique used for generating a film on the surface of a substrate such as silicon in a semiconductor element manufacturing process introduces an inert gas such as Ar gas into a vacuum vessel and exhausts it with a vacuum pump. The plasma is generated by applying a direct current or a high-frequency voltage to a target made of a film material to be formed in a vacuum vessel, and a negative potential is applied to generate Ar ions in the plasma. It is made to collide with the target and the film material particles pop out. The ejected particles adhere to the opposing substrate and form a film.

Furthermore, as disclosed in Patent Document 1, for example, a microwave plasma processing apparatus that generates plasma by the interaction between a microwave and a magnetic field and performs dry etching or sputtering has been proposed. In this microwave plasma processing apparatus, the side surface of a vacuum vessel is formed of ceramics, and a waveguide is connected to that portion, so that microwaves can be introduced into the vacuum vessel. Further, a magnetic field generator such as an electromagnet is provided outside the vacuum vessel, and a counter electrode facing the sample stage electrode is provided below the vacuum vessel, and the counter electrode is formed of a sputtering target material.
JP-A-6-29087

  As described in the background art above, generally, sputter deposition and etching are responsible for film formation and groove processing, which are independent processes in the semiconductor element manufacturing process. It has been used as a completely independent device. Therefore, in both cases, the apparatus installation space and cost are required in each process. In addition, since sputter deposition and etching are performed in a vacuum, it is necessary to remove the element substrate to the atmosphere and transfer it to the next vacuum container again to process it in a vacuum for continuous processing. There is. Therefore, useless time was spent on taking out the substrate to the atmosphere and evacuating the substrate loading container. In addition, surface contamination due to exposure of the substrate to the atmosphere also occurs.

  Furthermore, as disclosed in Patent Document 1, if the microwave is introduced from the side of the vacuum vessel through the insulator window and the target is disposed on the electrode facing the substrate, the etching and sputtering functions can be realized in the same vacuum vessel. Although it is possible, in this apparatus, film adhesion to the microwave introduction window by sputtering is inevitable, and when the adhesion film is a conductor, the microwave is cut off and the function of the apparatus is lost. is there.

The present invention has been made in view of the above-described conventional technique. By using plasma with a simple apparatus, different processes such as etching and sputtering can be performed in one container, and high-speed etching and high-speed film formation can be performed. It is an object of the present invention to provide a plasma processing method and apparatus that enable the above.

The present invention is provided with a vacuum container that can be evacuated inside, a magnet that is provided in the vacuum container and forms a magnetic field in the vacuum container, and is opposed to each other with a gap in the vacuum container. A plasma processing method for performing plasma processing using a plasma processing apparatus provided with a pair of electrodes, wherein the plasma processing method is fixed to a side wall of the vacuum container and protrudes into the vacuum container to emit microwaves, thereby resonating the vacuum container. In the vacuum vessel as a vessel, an antenna for generating plasma by electron cyclotron resonance together with the magnet, a target connected to one electrode side in the vacuum vessel to which a DC voltage or a high frequency voltage is applied, and a connection to the target It has a switching member which is connected to one contact a target voltage source for applying the DC voltage or the high frequency voltage, the other A substrate where the points are connected to the ground potential, a first switch for switching between ground potential and the voltage source for the target by the switching member, which is connected to the other electrode plasma treatment of the vacuum chamber is subjected, A switching member connected to the other electrode, wherein one contact is connected to a high-frequency power source, the other contact is connected to a ground potential, and a second member that switches between the high-frequency power source and the ground potential by the switching member. When the dry etching is performed, the first switch is connected to the ground potential, the second switch is connected to the high-frequency power source, and the evacuated vacuum vessel is supplied with a reactive gas. introducing the microwave from the antenna radiates in the vacuum chamber to generate plasma by the microwave radiated from the antenna, before Confining the plasma to a mirror magnetic field produced by the permanent magnet, the by ions in the plasma bombard the substrate on the other electrode, when performing sputtering, a voltage source for the target when the target is conductive as the DC voltage, connecting the first switch to the voltage source for the target, connecting the second switch to said ground potential, a plasma by introducing an inert gas into the vacuum vessel is evacuated When the target is insulative, the target voltage source is the high frequency voltage, the first switch is connected to the target voltage source, and the second switch is connected to the ground potential. In the sputtering, the plasma is confined in the mirror magnetic field, and ions in the plasma are At a location where the mirror magnetic field created by the magnet and the electric field created by the voltage applied to the target are orthogonal to each other, the force directed to the target is received, the surface of the target is bombarded, and each plasma in the vacuum vessel, This is a plasma processing method in which a dry etching process and a sputtering process are continuously performed. When performing the dry etching, a reactive gas is introduced into the vacuum vessel and controlled to a pressure of about 10 ⁻¹ Pa. When performing the sputtering, an inert gas is introduced into the vacuum vessel. -The pressure is controlled to about ¹ Pa.

The present invention also provides a vacuum vessel capable of evacuating the interior, a magnet provided in the vacuum vessel and forming a magnetic field in the vacuum vessel, and facing each other with a gap in the vacuum vessel. A plasma processing apparatus comprising a pair of electrodes, wherein the plasma processing apparatus is fixed to a side wall of the vacuum vessel and projects into the vacuum vessel to emit microwaves, and the vacuum vessel is used as a resonator in the vacuum vessel, An antenna for generating plasma by electron cyclotron resonance together with a magnet, a target connected to one of the electrodes in the vacuum vessel to which a DC voltage or a high-frequency voltage is applied , and a switching member connected to the target, the contact is connected to a voltage source for the target for applying the DC voltage or the high frequency voltage, the other contact is connected to a ground potential, said target A first switch for switching use voltage source and the ground potential by the switching member, a substrate which is connected to the other electrode plasma treatment of the vacuum chamber is performed, the connected to the other electrode switching member A first switch connected to a high-frequency power source, a second contact connected to a ground potential, and a second switch that switches between the high-frequency power source and the ground potential by the switching member. When the plasma is generated in the vacuum vessel by switching between the first switch and the second switch, and dry etching is performed, the first switch is connected to the ground potential, and the second switch A switch is connected to the high-frequency power source, a reactive gas is introduced into the evacuated vacuum vessel, and a microwave is radiated from the antenna into the vacuum vessel. When generating plasma by microwaves radiated from the antenna, confining the plasma in a mirror magnetic field created by the permanent magnet, bombarding the substrate on the other electrode by ions in the plasma, and performing sputtering When the target is conductive, the target voltage source is the DC voltage, the first switch is connected to the target voltage source, the second switch is connected to the ground potential, and the exhaust is exhausted. An inert gas is introduced into the vacuum vessel generated to generate plasma, and when the target is insulative, the target voltage source is set as the high-frequency voltage, and the first switch is set as the target voltage source. And connecting the second switch to the ground potential to generate plasma, and during the sputtering, The plasma is confined in a mirror magnetic field, and ions in the plasma receive a force directed toward the target at a location where the mirror magnetic field created by the permanent magnet and the electric field created by the voltage applied to the target are orthogonal to each other, and In the plasma processing apparatus, the surface of the target is bombarded, and dry etching processing and sputtering processing can be continuously performed by the respective plasmas in the vacuum vessel .

The magnet is a permanent magnet, the inside of the vacuum vessel to face the permanent magnet, the target is fixed.

  The vacuum vessel is formed of a conductive non-magnetic material, the magnet is provided on the upper lid of the vacuum vessel, and the upper lid and the side surface of the vacuum vessel are insulated. The inner surface of the vacuum vessel is formed in a rough surface having fine irregularities on the surface.

  According to the present invention, different processes such as etching and sputtering can be performed by one vacuum container, and a plurality of processing steps can be performed without taking out the material to be processed from the vacuum container. As a result, the number of processing devices required in the semiconductor process or the like can be reduced, the working efficiency can be increased, and the installation space for the devices can be saved. Furthermore, since ECR is used for the plasma source, high-speed processing is possible in etching and sputtering.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The plasma processing apparatus according to this embodiment includes an ECR apparatus using, for example, a microwave of 2.45 GHz. As shown in FIG. 1, the plasma processing apparatus 10 of this embodiment includes a cylindrical vacuum vessel 12 formed of a non-magnetic conductor such as aluminum, and an ECR plasma generated in the vacuum vessel 12. A predetermined annular permanent magnet 14 for forming a mirror magnetic field is provided. The permanent magnet 14 is fixed to the inner surface of the upper lid 16 of the vacuum container 12.

  The vacuum vessel 12 is formed in a cylindrical shape and also functions as a microwave cavity resonator. The inside of the vacuum vessel 12 is provided so as to be able to be sealed, and can be maintained in a state close to a vacuum. The upper lid 16 is connected to the end edge of the side surface portion 12a of the vacuum vessel 12 through an insulating ring 40 such as rubber, and can maintain an airtight state, and can securely connect between the upper lid 14 and the vacuum vessel side surface portion 12a. Insulated.

  The inner surface 12a of the vacuum vessel 12 has fine irregularities formed by a surface treatment method such as sandblasting. Thereby, the reaction product adhering when the sputtering process or the CVD process is performed is firmly fixed to the inner surface 12a.

  A gas inlet 18 is provided on the side of the permanent magnet 14 of the upper lid 16, and an exhaust pump 20 is connected to the lower part of the vacuum vessel 12, so that the gas introduced from the gas inlet 18 passes through the vacuum vessel 12. It passes through and is exhausted by the exhaust pump 20.

  The vacuum vessel 12 includes a conductive target 22 that also serves as one electrode and the other electrode 24 at an interval of n / 2 (n is a natural number) times the wavelength of the microwave in the vacuum vessel 12. Is provided. The target 22 is a film forming material for sputtering described later, and is attached to the surface of the permanent magnet 14 on the vacuum container side. In addition, when the target 22 is an insulating material, it is provided on an electrode of a predetermined conductive material.

  An antenna 26 that radiates microwaves into the vacuum vessel 12 is attached to the side wall of the vacuum vessel 12 near the permanent magnet 14. The position of the antenna 26 is fixed at a position separated from the upper lid 16 provided with the target 22 by a length of about ¼ of the in-tube wavelength of the microwave. The position of the antenna 26 is a position where the value of the electric field strength in the TE01 mode among the microwave electromagnetic field modes in the vacuum chamber 12 is almost the maximum.

  The plasma processing apparatus 10 is an ECR apparatus that generates plasma by ECR in the vacuum container 12, and in the central axis direction of the vacuum container 12, among the microwave electromagnetic field modes in the vacuum container 12, the TE01 mode. In the standing wave distribution of the electric field strength, the antenna 26 is installed at a position where the electric field strength is almost the maximum, and the direction of the magnetic field lines of the external magnetic field by the permanent magnet 14 in the vacuum vessel 12 and the TE01 mode of the microwave. The permanent magnet 14 is set so that the direction of the electric field is substantially orthogonal and the electric field intensity value in the TE01 mode is substantially maximum so as to substantially match the ECR condition.

  Below the vacuum vessel 12, a substrate mounting portion 28 is located, and an electrode 24 on which a substrate 30 as a material to be processed is placed is mounted.

  The electrode 24 is connected to a predetermined high-frequency power source 32 via a switch 34. The switch 34 has a switching member 34a, and the connection of the electrode 24 is switched between a high-frequency power source side contact 34b and a ground potential side contact 32c. . The target 22 also serving as an electrode is connected to a predetermined DC high voltage source 36, which is a target voltage source, via a switch 38. The switch 38 includes a switching member 38a, and the target 22 is connected to the predetermined DC. Switching is performed between a contact 38b on the high voltage source 36 side and a contact 38c on the ground potential side.

  In the operation of the plasma processing apparatus 10 according to this embodiment, the plasma source used for dry etching and the plasma source used for sputtering are shared, and the operation is performed on the target 22 installed in the vicinity of the permanent magnet 14 which is a main element of the plasma source. Switching between etching and sputtering is performed depending on how the potential is applied.

First, when performing a dry etching process, a reactive gas such as CF ₄ or O ₂ is introduced into the vacuum vessel 12 from the gas inlet 18, and the pressure is controlled while being exhausted to about 10 ⁻¹ Pa by the exhaust pump 20. Thereafter, a microwave of about 2.45 GHz is introduced from the antenna 26 of the microwave introduction unit and radiated into the vacuum container 12. At this time, the switch 34 is connected to the high frequency power supply 32 side, and the switch 38 is connected to the ground potential side. A high frequency power of 1 to 10 MHz is applied from the high frequency power supply 32 to the electrode 24.

  Plasma is generated by the microwave radiated from the antenna 26 and is confined in a mirror magnetic field formed by the permanent magnet 14, and efficiently becomes a high-density plasma in a region that satisfies the ECR condition. Ions in the plasma are accelerated by a DC bias due to the high frequency of the electrode 24, impact the substrate 30 on the electrode 24, and physicochemically etch the surface. At this time, since the target 22 is connected to the ground potential, ions in the mirror magnetic field are accelerated mainly toward the electrode, and the impact on the target 22 is small.

Next, when performing sputtering, an inert gas such as Ar is introduced into the vacuum vessel 12 from the gas inlet 18 and the pressure is controlled while exhausting to about 10 ⁻¹ Pa by the exhaust pump 20. The switch 34 is connected to the ground side, and the switch 38 is connected to the DC voltage source 36 side. Thereafter, when the target 22 is conductive, when a DC voltage of about several hundred to 1000 V is applied by the DC high voltage source 36, plasma is generated in the vacuum vessel 12. As described above, the plasma source used for dry etching and the plasma source used for sputtering are shared, and also in sputtering, the plasma is confined in the mirror magnetic field created by the permanent magnet 14 and efficiently becomes a high-density plasma. . When the target 22 is an insulating material, a high frequency voltage is applied. Thereby, Ar ions in the plasma receive a force toward the target 22 at a location where the magnetic field generated by the permanent magnet 14 and the electric field generated by the voltage applied to the target 22 are orthogonal to each other, impact the surface of the target 22, and sputtering is performed. appear. The target material particles popped out by sputtering adhere to the surface of the substrate 30 on the opposing electrode 24, and film formation is performed.

According to the plasma processing method and apparatus of this embodiment, switching between dry etching and sputtering is performed by switching the switches 34 and 38 in order to switch the potential of the target 22 and the electrode 24, and from the gas inlet 18 to the vacuum vessel 12. It is performed only by switching the gas introduced into the interior, and there is no need to replace any parts. Therefore, switching can be performed in a very short time. Furthermore, these two types of processing can be easily performed continuously. In the conventional apparatus, since the two apparatuses are used, the process in which the substrate 30 has to be once taken out to the atmosphere is always performed in a vacuum. Two types of processing can be executed while maintaining Therefore, not only the processing time can be shortened, but also various processes can be performed in a highly clean environment that is particularly important in semiconductor manufacturing.

  Furthermore, since the inner surface 12a of the vacuum vessel 12 is a rough surface having fine irregularities formed thereon, the product attached to the inner surface 12a by different processing steps such as sputtering can be firmly fixed and easily peeled off. I won't let you. If this treatment is not applied to the inner surface 12a, the product generated in the previous step easily peels off and scatters from the inner surface, causing particle contamination inside the vacuum vessel 12. In this embodiment, such contamination is also caused. Processing operations that do not occur and require high-purity conditions are also possible.

  In addition, the vacuum device as in this embodiment is expensive to use, such as an exhaust pump, a vacuum valve, and a pressure measuring instrument, and requires high cleanliness and high accuracy in the processed parts as well. For some reason, the production cost is very high. On the other hand, the processing apparatus according to the present invention can provide two kinds of functions with one apparatus, and since only one apparatus is required in the past, there is an advantage in terms of economy and work space. Very big. Further, since the antenna 26 protrudes into the vacuum vessel 12, even if a conductive material or other material adheres to the antenna 26, there is no influence on the microwave radiation.

  The magnet of the present invention may be an electromagnet in addition to a permanent magnet, and the number and position thereof can be set as appropriate. Further, the frequency of the microwave and the type of plasma and ions to be generated can be selected as appropriate. In addition to the above embodiment, the shape of the antenna can be appropriately selected from a linear or L-shaped rod antenna, a dipole antenna, a loop antenna, or the like.

It is a schematic sectional drawing of the plasma processing apparatus of one Embodiment of this invention.

DESCRIPTION OF SYMBOLS 10 Plasma processing apparatus 12 Vacuum vessel 14 Permanent magnet 16 Upper lid 18 Gas inlet 20 Exhaust pump 22 Target 24 Electrode 26 Antenna 28 Substrate attachment part 30 Substrate 32 High frequency power supply 34, 38 Switch 36 DC high voltage source

Claims (4)

A vacuum vessel capable of evacuating the inside, a magnet provided in the vacuum vessel and forming a magnetic field in the vacuum vessel, and a pair of electrodes provided facing each other at an interval in the vacuum vessel; In a plasma processing method for performing plasma processing using a plasma processing apparatus comprising:
An antenna that is fixed to a side wall of the vacuum vessel and projects into the vacuum vessel to emit microwaves, and the vacuum vessel is used as a resonator in the vacuum vessel to generate plasma by electron cyclotron resonance together with the magnet;
A target connected to one electrode side in the vacuum vessel and applied with a DC voltage or a high-frequency voltage;
A switching member connected to the target, wherein one contact is connected to a target voltage source for applying the DC voltage or the high-frequency voltage, and the other contact is connected to a ground potential; A first switch for switching a ground potential by the switching member;
A substrate connected to the other electrode in the vacuum vessel and subjected to the plasma treatment;
A switching member connected to the other electrode, wherein one contact is connected to a high-frequency power source, the other contact is connected to a ground potential, and a second member that switches between the high-frequency power source and the ground potential by the switching member. A switch,
When dry etching is performed, the first switch is connected to the ground potential, the second switch is connected to the high-frequency power source, and a reactive gas is introduced into the evacuated vacuum vessel, A microwave is radiated from the antenna into the vacuum container, a plasma is generated by the microwave radiated from the antenna , the plasma is confined in a mirror magnetic field formed by the permanent magnet, and the other electrode is ionized by ions in the plasma. Impact the substrate on top,
When performing sputtering, if the target is conductive, the target voltage source is the DC voltage, the first switch is connected to the target voltage source, and the second switch is connected to the ground potential. An inert gas is introduced into the evacuated vacuum vessel to generate plasma, and when the target is insulative, the target voltage source is the high-frequency voltage, and the first switch is Connect to a target voltage source, connect the second switch to the ground potential to generate plasma,
During the sputtering, the plasma is confined in the mirror magnetic field, and ions directed to the target at a location where the mirror magnetic field generated by the permanent magnet and the electric field generated by the voltage applied to the target are orthogonal to each other in the plasma. Receiving, impacting the surface of the target,
A plasma processing method, wherein dry etching processing and sputtering processing are continuously performed by the respective plasmas in the vacuum vessel. When performing the dry etching, a reactive gas is introduced into the vacuum vessel and controlled to a pressure of about 10 ⁻¹ Pa. When performing the sputtering, an inert gas is introduced into the vacuum vessel. The plasma processing method according to claim 1, wherein the pressure is controlled to about ¹ Pa. A vacuum vessel capable of evacuating the inside, a magnet provided in the vacuum vessel and forming a magnetic field in the vacuum vessel, and a pair of electrodes provided facing each other at an interval in the vacuum vessel; In a plasma processing apparatus comprising:
An antenna that is fixed to a side wall of the vacuum vessel and projects into the vacuum vessel to emit microwaves, and the vacuum vessel is used as a resonator in the vacuum vessel to generate plasma by electron cyclotron resonance together with the magnet;
A target connected to one electrode side in the vacuum vessel and applied with a DC voltage or a high-frequency voltage;
A switching member connected to the target, wherein one contact is connected to a target voltage source for applying the DC voltage or the high-frequency voltage, and the other contact is connected to a ground potential; A first switch for switching a ground potential by the switching member;
A substrate connected to the other electrode in the vacuum vessel and subjected to the plasma treatment;
A switching member connected to the other electrode, wherein one contact is connected to a high-frequency power source, the other contact is connected to a ground potential, and a second member that switches between the high-frequency power source and the ground potential by the switching member. With a switch,
Switching between the first switch and the second switch, each plasma can be generated in the vacuum vessel,
When dry etching is performed, the first switch is connected to the ground potential, the second switch is connected to the high-frequency power source, and a reactive gas is introduced into the evacuated vacuum vessel, A microwave is radiated from the antenna into the vacuum container, a plasma is generated by the microwave radiated from the antenna, the plasma is confined in a mirror magnetic field formed by the permanent magnet, and the other electrode is ionized by ions in the plasma. Impact the substrate on top,
When performing sputtering, if the target is conductive, the target voltage source is the DC voltage, the first switch is connected to the target voltage source, and the second switch is connected to the ground potential. An inert gas is introduced into the evacuated vacuum vessel to generate plasma, and when the target is insulative, the target voltage source is the high-frequency voltage, and the first switch is Connect to a target voltage source, connect the second switch to the ground potential to generate plasma,
During the sputtering, the plasma is confined in the mirror magnetic field, and ions in the plasma are directed to the target at a location where the mirror magnetic field generated by the permanent magnet and the electric field generated by the voltage applied to the target are orthogonal to each other. Receiving force, impacting the surface of the target,
A plasma processing apparatus characterized in that a dry etching process and a sputtering process can be continuously performed by each plasma in the vacuum vessel .   The plasma processing apparatus according to claim 3, wherein the magnet is a permanent magnet, and the target is fixed inside the vacuum vessel so as to face the permanent magnet.

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