JP6102816B2 - Film forming apparatus, film forming method, and film forming program - Google Patents

Description

  The present invention relates to a film forming apparatus, a film forming method, and a film forming program for forming a film on the surface of a conductive material such as steel using plasma.

  2. Description of the Related Art Conventionally, various film forming apparatuses that use plasma to form a coating on the surface of a material to be processed such as a steel material have been proposed. For example, a technique for forming diamond-like carbon (hereinafter referred to as “DLC”) on the surface of a work material is known from Patent Document 1 (Japanese Patent Laid-Open No. 2004-47207) and the like.

  In the technique disclosed in Patent Document 1, a rod-shaped work material is disposed in the plasma generation apparatus so as to protrude from the inner surface of the quartz window in the processing container. The plasma generation apparatus supplies a microwave through a quartz window, which is a microwave supply port, toward a workpiece material arranged in the processing container. Thereby, plasma is generated in the peripheral region of the inner surface of the quartz window. The material to be processed is covered with the generated plasma, and a sheath layer is generated.

  The plasma generation apparatus applies a negative bias voltage to the material to be processed while the microwave is supplied. As a result, the generated sheath layer expands along the surface of the workpiece material. The supplied microwave propagates as a surface wave of high energy density along the expanded sheath layer. As a result, the plasma extends to a portion of the workpiece material away from the periphery of the quartz window, that is, from one end of the workpiece material on the quartz window side to the other end protruding into the processing container. As a result, the source gas is plasma-excited by surface waves to become high-density plasma, and film formation is performed on the entire surface of the material to be processed.

JP 2004-47207 A

  Here, in the film forming method described in Patent Document 1, high-density plasma is formed so as to cover the material to be processed, and the surface temperature of the material to be processed continues to rise as the film formation proceeds. When the film formation start temperature is high, it is conceivable that the material to be processed exceeds the processing limit temperature of the material to be processed before the film is formed to a target film thickness. Therefore, there is a demand to start film formation at a temperature as low as possible in order to form a predetermined film thickness below the processing limit temperature. Therefore, if the temperature at the time of film formation is lowered, the activity of the chemical reaction on the processing surface is unstable, and defects at the film formed on the surface of the material to be processed have a high temperature at the time of film formation. More than the case.

  In order to solve the above-described problems, an object of the present invention is to provide a film forming apparatus, a film forming method, and a film forming program capable of reducing film defects generated on the surface of a material to be processed.

In order to achieve the object, a film forming apparatus according to claim 1 includes a gas supply unit that supplies a gas to a processing vessel provided with a conductive material to be processed, and plasma along a processing surface of the material to be processed. A microwave supply unit that supplies a pulsed microwave for generating a negative voltage, and a negative voltage application unit that applies a negative bias voltage to the workpiece material to expand a sheath layer along a treatment surface of the workpiece material; A microwave supply port for propagating the microwave supplied from the microwave supply unit to the expanded sheath layer, and a negative bias applied to the workpiece material by the negative voltage application unit in the microwave supply unit during the period in which the voltage is applied, the control unit for controlling so as to supply the microwaves pulsed supplied along the processing surface of the work piece, the surface of the material to be processed Comprising a detector for detecting a degree, a, when the surface temperature of the processed material to be detected through the detection portion is 300 ° C. or less, the control unit, the micro to be supplied to the microwave supply unit Film formation is performed by controlling the supply time per pulse of the wave to 100 μsec or less .

The film forming apparatus according to claim 2, A film forming apparatus according to claim 1, wherein, the microwave supply unit, the supply stop time between the pulsed microwave successive pulses 1μ Control is performed so that the microwave is supplied at intervals of seconds or more.

The film forming apparatus according to claim 3 is the film forming apparatus according to claim 1 or 2 , wherein the control unit supplies the pulsed microwave by the microwave supply unit and applies the negative voltage. the timing of the application of the negative bias voltage by section, characterized in that the control such Ru synchronized.

According to a fourth aspect of the present invention, there is provided a film forming method comprising: a microwave supply unit that supplies a pulsed microwave to a conductive work material via a microwave supply port; and a negative bias voltage applied to the work material. A negative voltage application unit, a control unit that controls the supply of the microwave by the microwave supply unit , and a detection unit that detects a surface temperature of the material to be processed. In the film method, the negative voltage application unit applies a negative bias voltage to the workpiece material to expand a sheath layer along the processing surface of the workpiece material, and the control unit includes: the microwave supply unit, in the period in which the negative bias voltage the material to be processed by the negative voltage application unit is applied, the pulsed microphone for generating plasma along the processing surface of the material to be processed By supplying the waves, and a microwave supply control step of the control to propagate into the sheath layer which is enlarged microwave, the surface temperature of the processed material to be detected through the detecting section 300 A temperature determining step for determining whether or not the temperature is equal to or lower than ° C., and it is determined that the surface temperature of the workpiece material detected through the detection unit in the temperature determining step is equal to or lower than 300 ° C. In the microwave supply control step, the control unit performs film formation by controlling the supply time per pulse of the microwave supplied to the microwave supply unit to 100 μsec or less. To do.

According to a fifth aspect of the present invention, there is provided a film forming program comprising: a microwave supply unit that supplies a pulsed microwave to a conductive work material via a microwave supply port; and a negative bias voltage applied to the work material. A negative voltage application unit, and a detection unit that detects a surface temperature of the workpiece material, and the pulsed microwave supplied through the microwave supply port is applied by the negative voltage application unit. is expanded by a negative bias voltage, the by propagating the sheath layer along the processing surface of the material to be processed, depending on the computer to control a film forming apparatus for forming a film, to the negative voltage application unit, the object A negative voltage application step of applying a negative bias voltage to the workpiece material to expand the sheath layer along the processing surface of the workpiece material; and the microwave supply unit to the workpiece by the negative voltage application unit In a period in which a negative bias voltage is applied to the charge, the control step of controlling so as to supply the pulsed microwave for generating plasma along the processing surface of the workpiece material, the detection A temperature determination step for determining whether or not the surface temperature of the workpiece material detected through a section is 300 ° C. or less, and a film formation program for causing the film formation apparatus to execute the temperature determination step If it is determined that the surface temperature of the work material detected through the detection unit is 300 ° C. or less, one pulse of the microwave to be supplied to the microwave supply unit in the control step The film forming apparatus is caused to execute so as to control the pertinent supply time to 100 μsec or less .

In the film forming apparatus according to claim 1, the film forming method according to claim 4 , and the film forming program according to claim 5 , in a state where the surface temperature of the work material detected through the detection unit is 300 ° C. or less, via the control unit, the microwave supply unit is deposited is controlled so that the supply time per one pulse of microwave pulsed supplied along the processing surface of the work piece becomes less than 100μ seconds done Ru.

As a result, when the film formation start temperature is a relatively low temperature of 300 ° C. or lower, even if the surface defects of the film are likely to occur, the supply time per pulse of the pulsed microwave is 100 μm. by controlling so that the second or less, it is isosamples suppressing the occurrence of surface defects of the film to improve the quality of the film.

In the film forming apparatus according to the second aspect , the microwave supply unit supplies the microwave by setting the supply stop time between the pulses of the continuous pulsed microwave to 1 μsec or more. Thus, plasma generation by pulsed microwave is intermittently, which makes it isosamples suppressing the occurrence of surface defects of the film to improve the quality of the film.

In the film forming apparatus according to claim 3 , the control unit controls the microwave supply unit and the negative voltage application unit so that the supply of the pulsed microwave and the application of the negative bias voltage are synchronized. That is, during the time the pulsed microwave is supplied, bias voltage is applied from the synchronization negative voltage application unit thereto. Thus, generation of plasma to cover the work piece becomes intermittent, thereby to suppress the occurrence of surface defects of the film to improve the quality of the film can Rukoto.

It is explanatory drawing which shows schematic structure of the film-forming apparatus which concerns on 1st Embodiment. It is a block diagram which shows the electrical structure of the film-forming apparatus. It is a schematic diagram of the waveform of a microwave pulse and the waveform of a negative bias voltage pulse. It is a table which shows the film-forming conditions at the time of forming a DLC film. It is a graph which shows the temperature increase rate per unit film thickness of a film. It is a flowchart of the film-forming process program performed with the film-forming apparatus. It is a flowchart of the 1st film-forming process of the film-forming process program performed with the film-forming apparatus. It is a table which shows the relationship between the supply time per pulse of a microwave, and the number of surface defects of a film. It is a graph which shows the relationship between the supply time per pulse of a microwave, and the number of surface defects of a film. It is a flowchart of the 2nd film-forming process of the film-forming process program performed with the film-forming apparatus which concerns on 2nd Embodiment.

  Hereinafter, a film forming apparatus according to the present invention will be described in detail with reference to the drawings based on a first embodiment and a second embodiment that embody the present invention. First, a schematic configuration of the film forming apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic diagram illustrating an overall configuration of a film forming apparatus 1 according to the first embodiment. As shown in FIG. 1, the film forming apparatus 1 according to the present embodiment includes a processing vessel 2, a vacuum pump 3, a gas supply unit 5, a control unit 6, and the like. The processing container 2 is made of metal such as stainless steel and has a hermetic structure. The vacuum pump 3 is a pump capable of evacuating the inside of the processing container 2 via a pressure adjusting valve 7 described later. Inside the processing container 2, a microwave supply port 22 made of a dielectric such as quartz is provided.

The gas supply unit 5 supplies a film forming source gas and an inert gas into the processing container 2. Specifically, an inert gas such as He, Ne, Ar, Kr, or Xe and a source gas such as CH ₄ , C ₂ H ₂ , or TMS (tetramethylsilane) are supplied. In the present embodiment, CH ₄ and TMS source gases are used for film formation.

The flow rates and pressures of the source gas and the inert gas supplied from the gas supply unit 5 may be controlled by the control unit 6 described later, or may be controlled by an operator. The source gas may be a gas containing a compound having a CH bond such as alkyne, alkene, alkane, aromatic compound, or a compound containing carbon. H ₂ may be included in the source gas.

  In the processing container 2, the central conductor of the coaxial waveguide 21 is extended at the center of the microwave supply port 22. A processing material 8 having conductivity on a rod-shaped surface is provided inside the processing container 2. The work material 8 is held by a conductive holder 9 made of stainless steel or the like. The workpiece 8 is held on the extension line of the central conductor of the coaxial waveguide 21 by the holder 9. In the microwave supply port 22, a dielectric such as quartz is disposed between the central conductor of the coaxial waveguide 21 and the holder 9 in order to maintain a vacuum. The material of the work material 8 is not particularly limited as long as the surface has conductivity, but is tempered steel in the present embodiment. Here, the tempered steel is a material such as JIS G4051 (carbon steel material for mechanical structure), G4401 (carbon tool steel material), G44-4 (steel material for alloy tool), or maraging steel material. In addition to tempered steel, the workpiece 8 may be ceramic or resin coated with a conductive material.

  The outer peripheral surface excluding the upper end surface of the microwave supply port 22, that is, the outer peripheral surface excluding the microwave introduction surface 22A, is covered with a side conductor 23 formed of a metal such as stainless steel. The side conductors 23 are fixed to the inner side surface of the processing container 2 by screws or the like, and are electrically connected to the processing container 2.

  Plasma for performing a DLC film forming process on the held work material 8 is generated inside the processing container 2. This plasma is generated by the microwave pulse controller 11, the microwave oscillator 12, the microwave power source 13 (see FIG. 2), the negative voltage power source 15, and the negative voltage pulse generator 16. In the present embodiment, surface wave excitation plasma is generated by a method disclosed in JP 2004-47207 A (hereinafter referred to as “MVP method (Microwave shear-Voltage combination Plasma method)”). In the following description, the MVP method will be described.

  The microwave pulse control unit 11 oscillates a pulse signal in accordance with an instruction from the control unit 6. The oscillated pulse signal is transmitted to the microwave oscillator 12. The microwave oscillator 12 generates a microwave pulse according to the pulse signal from the microwave pulse controller 11. The microwave power source 13 supplies power to the microwave oscillator 12 that oscillates a microwave of 2.45 GHz with the instructed output in accordance with an instruction of the control unit 6. The microwave oscillator 12 supplies a 2.45 GHz microwave in the form of a pulse according to a pulse signal from the microwave pulse control unit 11 and supplies it to an isolator 17 described later. The microwave is not limited to 2.45 GHz, and may be a pulse frequency of 0.3 GHz to 50 GHz.

  The microwave is transmitted from the microwave oscillator 12 to the isolator 17, the tuner 18, the waveguide 19, and the waveguide 19 via a coaxial waveguide 21 protruding from the waveguide 19 via a coaxial waveguide converter (not shown). It is supplied into the processing container 2 from the microwave introduction surface 22A of the supply port 22. The isolator 17 prevents the reflected wave of the microwave from returning to the microwave oscillator 12. The tuner 18 matches the impedances before and after the tuner 18 so that the reflected wave of the microwave is minimized.

  The film forming apparatus 1 includes a negative voltage power supply 15, a negative voltage pulse generator 16, and a negative voltage electrode 25. The negative voltage power supply 15 is connected to the control unit 6. The negative voltage power supply 15 supplies a negative bias voltage to the negative voltage pulse generator 16 in accordance with an instruction from the controller 6. The negative voltage pulse generator 16 pulsates the negative bias voltage supplied from the negative voltage power supply 15 into a pulsed negative bias voltage. This pulsing process is a process in which the negative voltage pulse generator 16 controls the magnitude, cycle, and duty ratio of a negative bias voltage pulse in accordance with an instruction from the controller 6. The negative voltage electrode 25 is electrically connected to the work material 8 or the holder 9. A negative negative bias voltage is applied to the workpiece material 8 by the negative voltage electrode 25. Even when the work material 8 is a metal substrate, or a ceramic or resin is coated with a conductive material, at least the entire processing surface of the work material 8 has a pulsed negative bias voltage. Is applied. A pulsed negative bias voltage is also applied to the entire surface of the holder 9 via the workpiece 8.

  The workpiece 8 is charged when a negative bias voltage is applied by the negative voltage electrode 25. When the workpiece material 8 is charged, the sheath layer generated by supplying the microwave from the microwave introduction surface 22 </ b> A is expanded around the workpiece material 8 in the enclosed space 20. The microwave is propagated to the processing surface of the holder 9 and the workpiece material 8 by the sheath layer expanded around the workpiece material 8. By supplying a pulsed microwave and applying a pulsed negative bias voltage at the same time, a surface wave excited plasma 28 is generated as shown in FIG.

[Detailed explanation of surface wave excitation plasma]
Usually, when generating surface wave excitation plasma, first, a microwave is supplied along an interface between a plasma having a certain level of electron (ion) density and a dielectric in contact with the plasma. The supplied microwave is propagated as a surface wave with the energy of electromagnetic waves concentrated on this interface. As a result, the plasma in contact with the interface is excited by a high energy density surface wave and further amplified. Thereby, a high density plasma is generated and maintained. However, when this dielectric is replaced with a conductive material, the conductive material does not function as a surface wave waveguide, and preferable surface wave propagation and plasma excitation cannot occur.

  On the other hand, an essentially unipolar charged particle layer, a so-called sheath layer, is formed near the surface of an object in contact with plasma. When the object is a work material 8 having conductivity to which a negative bias voltage is applied, the sheath layer is a layer having a low electron density, that is, a positive polarity, and substantially has a dielectric constant in the microwave pulse frequency band. It is a layer with a rate ε≈1. For this reason, the sheath thickness of the sheath layer can be increased by making the absolute value of the negative bias voltage to be applied larger than the absolute value of, for example, −100V. That is, the sheath layer expands. This sheath layer acts as a dielectric that propagates surface waves to the interface between the plasma and the object in contact with the plasma.

  Accordingly, the microwave is supplied from the microwave supply port 22 disposed in the vicinity of one end of the holder 9 that holds the workpiece 8, and a negative bias voltage is applied to the workpiece 8 and the holder 9. Then, the microwave propagates as a surface wave along the interface between the sheath layer and the plasma. As a result, high-density excitation plasma based on surface waves is generated along the surfaces of the workpiece 8 and the holder 9. This high-density excitation plasma is a surface wave excitation plasma 28 shown by a broken line in FIG.

The electron density of the high-density plasma due to surface wave excitation in the vicinity of the surface of the workpiece 8 reaches 10 ¹¹ to 10 ¹² cm ⁻³ . When the DLC film formation process is performed by plasma CVD using the MVP method, the film formation speed is 3 to 30 (nanometers / second), which is one to two orders of magnitude higher than the case where the DLC film formation process is performed by normal plasma CVD. Therefore, high-speed film formation is possible.

  In this MVP method, high-density excitation plasma is generated in the vicinity of the surfaces of the work material 8 and the holder 9 that are metal substrates, so that the surface temperature of the work material 8 and the holder 9 is equal to or higher than the tempering temperature, for example, The temperature rises from about 250 ° C to about 300 ° C. However, since high-speed film formation is possible, the film formation time is 1/10 to 1/100 of the normal plasma CVD film formation time. That is, since the film formation time can be shortened to several tens of seconds to several minutes, the softening of the work material 8 can be suppressed even if the surface temperature of the work material 8 exceeds the tempering temperature. In such high-speed film formation with a short film formation time, it is important to measure the surface temperature of the workpiece 8 during film formation with a low error using a radiation thermometer 29 described later.

  The negative voltage power supply 15 and the negative voltage pulse generator 16 are examples of the negative voltage application unit of the present invention. The microwave pulse control unit 11, the microwave oscillator 12, the microwave power source 13, the isolator 17, the tuner 18, the waveguide 19, and the coaxial waveguide 21 are examples of the microwave supply unit of the present invention. The film forming apparatus 1 includes the negative voltage power supply 15 and the negative voltage pulse generator 16, but may further include a positive voltage power supply and a positive voltage pulse generator, or instead of the negative voltage pulse generator 16. In addition, a negative voltage generator for applying a continuous negative bias voltage instead of a pulsed negative bias voltage may be provided.

  In the film forming apparatus 1, a radiation thermometer 29 is disposed at a position near the outside of the quartz window 27 provided on the side wall of the processing container 2. The radiation thermometer 29 continuously measures the surface temperature at any position of the processing surface in the range H1 shown in FIG. 1 from the upper end portion to the lower end portion of the processing material 8 among the processing surface of the processing material 8. To do. The radiation thermometer 29 may measure the surface temperature of the holder 9 protruding from the microwave supply port 22 to estimate the surface temperature of the processing surface of the workpiece 8. The radiation thermometer 29 is electrically connected to the control unit 6. A liquid crystal display (LCD) 30 is electrically connected to the control unit 6. A buzzer (not shown) or the like is electrically connected to the control unit 6. The radiation thermometer 29 is an example of the detection unit of the present invention.

The radiation thermometer 29 receives infrared rays having a center wavelength λ in the measurement wavelength band from the processing surface of the workpiece 8 and calculates the intensity V of the received infrared rays. The radiation thermometer 29 calculates and outputs the surface temperature of the processing surface of the workpiece 8 from the calculated infrared intensity V and the thermometer setting emissivity ε ₁ stored in advance. The radiation thermometer 29 outputs the calculated output temperature to the control unit 6 every predetermined time, for example, every 0.1 second.

  FIG. 2 is a schematic block diagram showing an outline of the electrical configuration of the film forming apparatus 1. As shown in FIG. 2, the control unit 6 includes a pressure adjustment valve 7, an atmosphere release valve 10, a vacuum gauge 26, a radiation thermometer 29, a liquid crystal display (LCD) 30, a negative voltage power supply 15, and a negative voltage pulse generator 16. The microwave pulse control unit 11, the gas supply unit 5, and the microwave power source 13 are electrically connected.

  The control unit 6 outputs control signals to the negative voltage power supply 15 and the microwave power supply 13 to control the applied power of the microwave pulse and the applied voltage of the pulsed negative voltage. The control unit 6 outputs a control signal to the negative voltage pulse generation unit 16 and the microwave pulse control unit 11, thereby applying the pulsed negative bias voltage application timing, supply voltage, duty ratio, and the microwave oscillator 12. The supply timing, duty ratio, and supply power of the generated microwave pulse are controlled.

  The control unit 6 outputs a flow rate control signal to the gas supply unit 5 to control the supply of the source gas and the inert gas. The control unit 6 outputs a control signal to the pressure adjustment valve 7 based on a pressure signal representing a pressure in the processing container 2 input from a vacuum gauge 26 attached to the processing container 2. The pressure adjusting valve 7 to which the control signal is input controls the pressure in the processing container 2 by adjusting the valve opening based on the pressure signal included in the control signal.

  The control unit 6 outputs fully open and fully closed control signals to the atmosphere release valve 10. The air release valve 10 to which the fully open control signal is input fully opens the valve opening. The atmospheric release valve 10 to which the fully closed control signal is input makes the valve opening fully closed. When the atmosphere release valve 10 is fully opened, the internal pressure of the processing container 2 becomes the same as the external pressure via the atmosphere release valve 10.

  The control unit 6 determines the end of the CPU 31, RAM 32, ROM 33, hard disk drive (hereinafter referred to as “HDD”) 34, timer 35 that measures the elapsed time of all film forming processes, ion cleaning, and DLC film forming processes. And a computer including an end determination timer 36 and the like. The CPU 31 temporarily stores various types of information in a volatile storage device such as the RAM 32 and executes a film formation processing program described later to control the entire film formation apparatus 1.

  The ROM 33 and the HDD 34 are nonvolatile storage devices, and store the film forming conditions for the film forming process performed by the film forming apparatus 1 and the film forming process program executed by the CPU 31. Specifically, the ROM 33 and the HDD 34 store data indicating the DLC film forming conditions shown in FIG. 4 and a film forming processing program whose processing procedure is shown in a flowchart in FIG. The data indicating the film formation conditions and the film formation processing program may be read from a storage medium such as a CD-ROM or DVD-ROM by a driver (not shown), or downloaded from a network such as the Internet (not shown). Good.

FIG. 4 is a DLC film forming condition table showing an example of the DLC film forming conditions executed by the film forming apparatus 1 in the first embodiment. In the DLC film formation condition table, for example, as shown in FIG. 4, as “gas flow rate (sccm)”, the inert gas Ar is “50 sccm”, the hydrogen H ₂ is “50 sccm”, and the methane CH ₄ is “100 sccm”. , TMS stores “20 sccm”, “pressure (Pa)” as “50 Pa”, “negative DC bias voltage (V)” as “−250 V”, “negative bias voltage pulse duty ratio (%)” “90%” is stored.

  FIG. 5 is a graph showing an example of a temperature increase rate per unit film thickness when film formation is performed according to the film formation conditions in the DLC film formation condition table of FIG. In the DLC film formation condition table 41 shown in FIG. 4 and the graph of the temperature rise rate per unit film thickness shown in FIG. 5, “microwave pulse duty ratio (%)” and “temperature rise rate (° C./μm)”. And correspond to each other. For example, when the microwave duty ratio is set to 50% as the film forming condition, the temperature increase rate is 68 (° C./μm). Further, when the duty ratio of the microwave pulse is set to 40% as the film forming condition, the temperature rising rate is 63 (° C./μm). The microwave pulse duty ratio (%) and the “temperature increase rate (° C./μm)” are, for example, the duty of the microwave pulse so that the temperature of the system in the processing container 2 does not rise too much by the start of film formation. The ratio (%) is set to about 50%, and the temperature increase rate at this time is 68 ° C./μm.

  When the CPU 31 executes the supply of microwaves and the application of a negative bias voltage in ion cleaning and film formation processing or film formation processing described later according to the film formation program, the pulsed microwaves are converted into microwaves. Supplyed from the supply port 22, a pulsed negative bias voltage is applied from the negative voltage electrode 25 to the workpiece 28. At this time, an example of the supply timing of the microwave pulse controlled by the CPU 31 and the application timing of the pulsed negative bias voltage will be described with reference to FIG. As shown in FIG. 3, the period of the microwave pulse 38 is T3 (seconds). The supply time for each pulse of the microwave pulse 38 is T2 (seconds). Therefore, the duty ratio, which is the ratio of the supply time for each pulse of the microwave pulse 38 to the period of the microwave pulse 38, is T2 / T3.

  The period of the pulsed negative bias voltage 39 is the same period as the period of the microwave pulse 38 and is T3 (seconds). The application time of the pulsed negative bias voltage 39 is (T4−T1) (seconds). At this time, the duty ratio that is the ratio of the application time for each pulse of the pulsed negative bias voltage 39 to the period of the pulsed negative bias voltage 39 is (T4−T1) / T3.

  The application timing of the pulsed negative bias voltage 39 is set to be delayed by T1 (seconds) from the supply start timing of the microwave pulse 38. Information indicating the delay time T1 (seconds) is stored in the ROM 33 or the HDD 34 of the control unit 6. Information indicating each time T2, T3, and T4 (seconds) is calculated by the CPU 31 from data stored in each DLC film formation condition table 41 stored in the ROM 33 or the HDD 34 of the control unit 6. The application time of the negative bias voltage is preferably equal to the time when the microwave pulse 38 is supplied or an integer multiple of one period of the microwave pulse 38.

[Film formation]
Next, FIG. 4 and FIG. 4 show the processing procedure of the film forming process performed by the CPU 31 of the film forming apparatus 1 configured as described above, in which a DLC film is formed on the processing surface of the material 8 to be processed. 6 will be described. FIG. 6 is a flowchart for explaining the processing procedure of the film forming processing program executed by the CPU 31. In this film forming process, first, the work material 8 held by the holder 9 is set in the processing container 2 by an operator.

  Thereafter, the CPU 31 detects that a film formation start instruction by an operator is input to the control unit 6 via an operation button provided on an operation unit (not shown). Start processing.

  As shown in FIG. 6, first, in step (hereinafter abbreviated as “S”) 11, the CPU 31 reads out the film formation conditions shown in the DLC film formation condition table 41 shown in FIG. 4 from the ROM 33 and the HDD 34 and stores them in the RAM 32. . In S <b> 11, the CPU 31 reads predetermined parameters such as film forming conditions from the ROM 33 or the HDD 34 and stores them in the RAM 32. The predetermined parameters are parameters such as an ion cleaning parameter and a gas flow rate value which will be described later. These parameters may be automatically set based on the film formation conditions stored in advance in the ROM 33 or the HDD 34. As for the film forming conditions, in S11, an operator may input each data to the control unit 6 via an operation unit (not shown), and the CPU 31 may store the input data in the RAM 32.

  Subsequently, in S12, the vacuum pump 3 is activated and the air in the processing container 2 is exhausted. Based on the pressure signal input from the vacuum gauge 26, the CPU 31 operates the vacuum pump 3 until the inside of the processing container 2 reaches a predetermined degree of vacuum (for example, less than 1.0 Pa). This predetermined degree of vacuum is stored in advance in the ROM 33 or the HDD 34. When the inside of the processing container 2 reaches a predetermined degree of vacuum, the CPU 31 executes the process of S14.

  When the inside of the processing container 2 reaches a predetermined degree of vacuum (for example, less than 1.0 Pa), in S14, the CPU 31 starts supplying the inert gas Ar. Specifically, the gas flow value of the inert gas Ar that is an ion cleaning parameter (for example, the gas flow rate is 50 sccm) is read from the RAM 32, and the processing container 2 is read with the gas flow value read out to the gas supply unit 5. A supply signal for instructing supply of the inert gas Ar is output. Thereafter, the CPU 31 sets the source gas and the inert gas in the processing container 2 to be exhausted at a constant flow rate via the pressure adjusting valve 7 and adjusts the inside of the processing container 2 to a predetermined pressure. The CPU 31 measures the pressure inside the processing vessel 2 based on the pressure signal input from the vacuum gauge 26. When the inside of the processing container 2 reaches a predetermined pressure, the CPU 31 executes the process of S16.

  In S <b> 16, the CPU 31 starts ion cleaning based on the ion cleaning parameters stored in the RAM 32. The ion cleaning parameters include a microwave output power (for example, 800 W) and a negative bias voltage pulse applied voltage (for example, −200 V). The ion cleaning is executed until the arcing occurrence frequency becomes less than a predetermined frequency. The predetermined frequency is stored in advance in the ROM 33 or the HDD 34. The CPU 31 transmits the negative bias voltage application timing to the negative voltage power supply 15. The CPU 31 transmits the microwave output power and the application timing of the microwave output power to the microwave power supply 13. When ion cleaning is performed and the arcing frequency is less than the predetermined frequency, the CPU 31 executes S18. Alternatively, when the ion cleaning time is set as the ion cleaning parameter, the CPU 31 may execute S18 when determining that the time measured by the timer 35 from the start of the ion cleaning has passed the ion cleaning time. .

  Here, specific processing in S16 will be described. Specifically, in S <b> 16, the CPU 31 transmits an application voltage of a negative bias voltage to the negative voltage power supply 15. The CPU 31 transmits microwave output power to the microwave power source 13. The CPU 31 sets the negative bias voltage period T3 (seconds) acquired in S11, the application time per pulse (T4-T1) (seconds), and the delay time T1 (seconds) from the microwave supply start timing. Based on this, a pulse signal indicating an ON signal indicating the application start timing of the negative bias voltage and an OFF signal indicating the application stop timing is transmitted to the negative voltage pulse generator 16. The CPU 31 turns on the ON signal indicating the supply start timing of the microwave and the OFF indicating the supply stop timing based on the period T3 (second) of the pulsed microwave acquired in S11 and the supply time T2 (second) of each pulse. A pulse signal indicating the signal is transmitted to the microwave pulse control unit 11.

  As a result, the negative voltage power supply 15 supplies a negative applied voltage to the negative voltage pulse generator 16 according to the received applied voltage. The negative voltage pulse generator 16 applies the supplied negative applied voltage at the application timing indicated by the pulse signal of the negative bias voltage received every cycle T3 (seconds) from the start of the microwave supply T1 (seconds). After a delay, the negative voltage electrode 25 is applied to the workpiece 8 for (T4−T1) seconds.

  Further, the microwave power supply 13 supplies power to the microwave oscillator 12 according to the received microwave output power. The microwave pulse control unit 11 uses the output power of the supplied microwave, and in accordance with the supply timing indicated by the received microwave pulse signal, the pulse signal for the supply time T2 (seconds) every cycle T3 (seconds). Is transmitted to the microwave oscillator 12. The microwave oscillator 12 generates a microwave having a supply time T2 (seconds) according to the received pulse signal at a period T3 (seconds) with a microwave power of 2.45 GHz corresponding to the supplied power, and is connected to the isolator 17 and the tuner. 18, supplied to the holder 9 and the work material 8 through the waveguide 19, the coaxial waveguide 21, and the microwave supply port 22.

  As a result, the sheath layer along the surface of the workpiece 8 is expanded in the direction orthogonal to the propagation direction of the microwave by these negative bias voltages, and the inert gas is generated by the microwave propagating in the sheath layer. Ar plasma is generated. The surface of the material 8 to be processed is ion-cleaned by the generated plasma of the inert gas Ar. When ion cleaning is performed, the surface temperature of the workpiece 8 increases.

  In S <b> 18, the CPU 31 first transmits a stop signal that instructs the microwave pulse control unit 11 to stop the pulse signal transmitted to the microwave oscillator 12. Thereby, the microwave oscillator 12 does not receive the pulse signal, and therefore stops outputting the microwave pulse 38. In addition, the CPU 31 transmits a stop signal that instructs the negative voltage pulse generator 16 to stop applying the negative bias voltage. As a result, the negative voltage pulse generator 16 stops applying the negative bias voltage to the workpiece 8.

  Thereafter, in S18, the CPU 31 reads out the respective gas flow values for supplying the source gas and the inert gas from the ROM 33 or the HDD 34, and transmits them to the gas supply unit 5 as a flow control instruction. In accordance with the instructions, the raw material gas and the inert gas are supplied into the processing container 2. In addition, each gas flow value which supplies raw material gas and an inert gas is memorize | stored in ROM33 or HDD34 previously. For example, the inert gas Ar is 50 sccm. H2 is 50 sccm and CH4 is 100 sccm. TMS is 20 sccm.

  In S <b> 18, after supplying the source gas and the inert gas, the CPU 31 sets the source gas and the inert gas in the processing container 2 to be exhausted at a constant flow rate via the pressure adjustment valve 7. Adjust so that the inside is at a predetermined pressure. Subsequently, based on the pressure signal input from the vacuum gauge 26, the CPU 31 performs a film forming process in S200 when the inside of the processing container 2 reaches a predetermined pressure.

  In S200, a film forming process is performed. In S <b> 200, the CPU 31 transmits a negative bias voltage application voltage to the negative voltage power supply 15. The CPU 31 transmits microwave output power to the microwave power source 13. The CPU 31 stores the negative bias voltage stored in the RAM 32 as a film forming condition, one pulse period T3 (second), one pulse application time (T4-T1) (second), and microwave supply start timing. The negative bias voltage pulse signal is transmitted to the negative voltage pulse generator 16 based on the delay time T1 (seconds) from the negative voltage pulse. The CPU 31 converts a microwave pulse signal into a microwave pulse control unit based on a pulsed microwave period T3 (seconds) stored in the RAM 32 as a film forming condition and a supply time T2 (seconds) for each pulse. 11 to send. In S18, when the source gas and the inert gas are supplied into the processing container 2, in S200, when a microwave is supplied and a negative voltage is applied to the work material 18, the surface of the work material 18 is obtained. Film formation is performed.

FIG. 8 shows the film formation start temperature that is the temperature at which S200 is performed and the time for each pulse of the supplied microwave when S200 is performed and film formation is performed on the workpiece 18. Accordingly, it is a correspondence table showing the number of defects generated per 1 mm ² of the surface of the work material 18.
In FIG. 9, the time for each pulse of the microwave is set on the horizontal axis and the number of surface defects is set on the vertical axis in accordance with the film formation start temperature in FIG. It is the graph which showed the number of surface defects which generate | occur | produces according to it.
In FIG. 8, 160 ° C., 200 ° C., 300 ° C., and 400 ° C. are set as the film formation start temperature, and the supply time per pulse of the pulsed microwave supplied to the workpiece 8 is 2 μs, 10 μs, 25 μs, 50 μs, 100 μs, 160 μs, 200 μs, 500 μs, and 1000 μs (1 msec) are set, and film formation is performed on the work material 18 using each combination as a film forming condition. The number of surface defects per mm ² generated in the DLC film when broken was shown.

The surface defect is measured by photographing the DLC film, and utilizing the fact that the surface defect is photographed darker than the surroundings, the surface image of the DLC film subjected to the binarization process with the density threshold value indicating brightness. Is set to 1 × 1 mm ² . Then, a portion where the diameter of a circumscribed circle inscribed by a darkly imaged portion within the set image processing range is 10 μm or more is extracted and measured as a threshold value for determining one surface defect. The threshold value of the number of surface defects that is judged to be a problematic DLC film is a conventional film formation condition in which the film formation start temperature is 400 ° C. and the supply time per pulse of microwave is 1000 μs. The number of surface defects per unit area of 1 × 1 mm ² of the formed DLC film is 18. When the number of surface defects measured per unit area of 1 × 1 mm ² is below the conventional level, it is determined that the surface of the workpiece 18 has no problem, and on the other hand, the number of surface defects is larger than the threshold value of the number of surface defects Determines that the surface of the workpiece 18 has a problem. A large number of surface defects is a problem because the surface defects may be the starting point and lead to film peeling.

  As shown in FIGS. 8 and 9, surface defects having different numbers of surface defects occurred in the DLC film according to the supply time per one pulse of the microwave for each condition of the film formation start temperature.

  In the DLC film formed at a film formation start temperature of 160 ° C., surface defects were not measured when the supply time per pulse of microwave was 2 μsec. One surface defect was measured when the supply time per pulse of the microwave was 10 μs. One surface defect was measured when the supply time per pulse of the microwave was 50 μsec. Ten surface defects were measured when the supply time per pulse of microwave was 100 μsec. When the supply time per pulse of the microwave was 160 μsec, 178 surface defects were measured. When the supply time per pulse of the microwave was 200 μs, 351 surface defects were measured.

  In the DLC film formed under the condition where the film formation start temperature is 200 ° C., no surface defects were measured when the supply time per one pulse of the microwave was 25 μsec. One surface defect was measured when the supply time per pulse of the microwave was 50 μsec. Ten surface defects were measured when the supply time per pulse of microwave was 100 μsec. When the supply time per pulse of microwave was 160 μsec, 55 surface defects were measured. When the supply time per pulse of the microwave was 200 μs, 108 surface defects were measured. When the supply time per pulse of the microwave was 500 μs, 424 surface defects were measured. When the supply time per pulse of the microwave was 1000 μsec, 1000 or more surface defects were measured.

  In the DLC film formed at a film formation start temperature of 300 ° C., one surface defect was measured when the supply time per pulse of the microwave was 50 μsec. When the supply time per pulse of the microwave was 100 μs, seven surface defects were measured. Twenty-six surface defects were measured when the supply time per pulse of microwave was 200 μsec.

  In the DLC film formed at a film formation start temperature of 400 ° C., surface defects were not measured when the supply time per pulse of the microwave was 50 μsec. Five surface defects were measured when the supply time per pulse of the microwave was 100 μs. Ten surface defects were measured when the supply time per pulse of the microwave was 500 μsec. Eighteen surface defects were measured when the supply time per pulse of microwaves, which is a conventional film forming condition, was 1000 μsec.

Thus, when the film formation start temperature is 300 ° C. or lower, it is desirable to control the supply time per pulse of the microwave to 100 μsec or shorter. When the processing surface temperature of the work material 8 is a relatively low temperature of 300 ° C. or less, the DLC film per unit area (1 mm ² ) is controlled by controlling the supply time per pulse of the microwave to 100 μsec or less. The number of surface defects can be made equal to or less than the threshold value of the number of surface defects. On the other hand, when the film formation start temperature is 300 ° C. or less and the supply time per one pulse of microwave is longer than 100 μsec, the number of surface defects of the DLC film becomes larger than the threshold value of the number of surface defects, There is a possibility that film peeling may occur starting from surface defects.

Further, in a high temperature range where the film formation start temperature is higher than 300 ° C., the supply time per one pulse of the microwave is not limited to 100 μsec or less. When the film formation start temperature is higher than 300 ° C., the number of surface defects of the DLC film per unit area (1 mm ² ) is calculated even if the supply time per pulse of microwave is longer than 100 μsec. It is possible to make the number below a threshold value.

[Film Forming Process of First Embodiment]
Therefore, in the film forming apparatus 1 of the first embodiment, in the film forming process program shown in FIG. 6, instead of the film forming process in S200, control for varying the microwave supply time according to the film forming start temperature is performed. A first film forming process is performed. FIG. 7 is a flowchart illustrating a processing procedure of a first film forming process that is an example of the film forming process. When the film forming process is executed, the film forming apparatus 1 receives the microwave per pulse selected when the film forming start temperature, which is the processing surface temperature of the material 8 to be processed, is 300 ° C. or less. The supply time (PWL) per pulse of the microwave selected when the supply time (PWS) and the film formation start temperature are higher than 300 ° C. are stored in the RAM 32 as film formation conditions. For example, 100 μsec is stored as the supply time (PWS), and 500 μsec is stored as the supply time (PWL).

In S18 of the film forming process shown in FIG. 6, when the inside of the processing container 2 reaches a predetermined pressure, the CPU 31 executes S20 of the first film forming process shown in FIG. In S20, the CPU 31 obtains the surface temperature T ₀ of the processing surface of the workpiece 8 that is continuously calculated and output by the radiation thermometer 29 in S20.

In subsequent S21, the product (K × t) of the temperature increase rate K (° C./μm) and the target film thickness t (μm) is based on the physical property values of the workpiece 8, the holder 9, etc. Is determined whether it is smaller than a difference ΔT (T _L −T ₀ ) from the processing surface temperature T ₀ of the workpiece 8 acquired in S20 from the limit temperature T _L determined by the heat resistance temperature of the base material and the coating film constituting Is done.
That is, it is determined whether K × t ≦ ΔT is satisfied. The temperature increase rate K, the target film thickness t, and the limit temperature _TL are preset in S11 and stored in the RAM 32. As the film formation proceeds, the surface temperature of the work material 8 continues to rise. Therefore, when the film formation start temperature is high, before the target film thickness t is reached, the base material and the film constituting the work material are formed. It is considered that the processing limit temperature determined by the heat-resistant temperature or the like is exceeded. The processing limit temperature is, for example, the softening temperature of the work material and the holder. In the MVP method that is the film forming method performed in the first embodiment, the temperature is likely to rise. Therefore, when the first film forming process is performed, before the film forming described later is performed, in S21, the limit temperature is set. It is desirable to determine _TL .

When the value of K × t is larger than ΔT in S21 (S21: NO), the processing surface temperature of the work material 8 is too high and ΔT is small. T ₀ is wait until the decline.
On the other hand, when the value of K × t is smaller than ΔT (S21: YES), the process surface temperature of the material 8 to be processed is sufficiently lowered, and the process proceeds to S22.

In S22. It is determined whether the processing surface temperature T ₀ of the workpiece 8 is 300 ° C. or lower. 300 ° C. is a temperature lower than the limit temperature T _L, and, to reach the limit temperature T _L is still temperature can afford.

When the processing surface temperature T ₀ of the workpiece 8 is 300 ° C. or lower (S22: YES), 100 μs (pulse frequency 2.5 kHz, duty ratio), which is a supply time (PWS) per one pulse of the microwave 25%) is selected, and the process proceeds to S25. On the other hand, when the processing surface temperature T ₀ of the workpiece 8 is higher than 300 ° C. (S22: NO), for example, when the processing surface temperature T ₀ is 400 ° C., a microwave supply time (PWL) per pulse. 500 μs (pulse frequency 1.0 kHz, duty ratio 50%) is selected, and the process proceeds to S25.

The supply time PW per one pulse of the microwave can be changed by changing both or one of the pulse frequency and the duty ratio of the pulsed microwave, but it is better to change one of them. Simple and desirable. When it is desired to set the duty ratio high and increase the film forming speed, the supply time PW can be set shorter by setting the pulse frequency to the upper limit of the power supply specification.
However, when a power supply of about several kHz is used, the upper limit of the duty ratio is limited in order to make the supply time PW 100 sec or less.
Incidentally, when a microwave power source capable of outputting with a high pulse frequency is provided, if the microwave pulse frequency at the time of initial film formation condition acquisition is set to a high pulse of several tens of kHz (for example, 10 kHz). Regardless of the duty ratio, the supply time PW can be set to 100 μsec or less.

  In S <b> 25, the CPU 31 reads the applied voltage value of “negative bias voltage (V)” from the RAM 32 and transmits it to the negative voltage power supply 15. The CPU 31 reads the supplied power value of “microwave output (kW)” from the RAM 32 and transmits it to the microwave power source 13. The CPU 31 starts the supply of the “negative bias voltage pulse duty ratio (%)”, the pulse signal indicating the ON signal and the OFF signal indicated by the cycle T3 (second) of one pulse of the negative bias voltage, and the microwave. Is read from the RAM 32 and transmitted to the negative voltage pulse generator 16. The CPU 31 reads out a pulse signal indicating an ON signal and an OFF signal indicated by “microwave pulse duty ratio (%)” and a period T3 (second) of one microwave pulse from the RAM 32 and transmits the pulse signal to the microwave pulse control unit 11. To do.

  As a result, the negative voltage power supply 15 supplies a negative applied voltage to the negative voltage pulse generator 16 according to the received applied voltage. The negative voltage pulse generation unit 16 receives the received “negative” voltage by delaying T1 (seconds) from the start of microwave supply every cycle T3 (seconds) according to the pulse signal received from the CPU 31 with the supplied negative applied voltage. The negative bias voltage of “bias voltage pulse duty ratio (%)” is applied to the workpiece 8 through the negative voltage electrode 25 for (T4−T1) seconds.

  Further, the microwave power supply 13 supplies power to the microwave oscillator 12 according to the received microwave output power. In accordance with the received “microwave pulse duty ratio (%)”, the microwave pulse control unit 11 generates a pulse signal during the supply time T2 (seconds) at every cycle T3 (seconds) indicated in the pulse signal received from the CPU 31. Transmit to the microwave oscillator 12. The microwave oscillator 12 generates a microwave pulse 38 having a supply time T2 (seconds) according to the received pulse signal with a microwave power of 2.45 GHz corresponding to the supplied power for every period T3 (seconds) of the pulse signal. The isolator 17, the tuner 18, the waveguide 19, the coaxial waveguide 21, and the microwave supply port 22 are supplied to the holder 9 and the work material 8.

  As a result, the sheath layer along the surface of the workpiece 8 is expanded in the direction orthogonal to the propagation direction of the microwave, that is, in the lateral direction of FIG. Plasma of the inert gas Ar is generated by the microwave propagating through the. The propagation direction of the microwave is a direction perpendicular to the microwave introduction surface 22A in the vicinity of the microwave supply port 22, but the microwave propagates along the sheath layer generated along the surface of the material 8 to be processed. Therefore, the propagation direction of the microwave is along the direction in which the work material 8 extends.

  Further, the microwave power supply 13 supplies power to the microwave oscillator 12 according to the received microwave output power. The microwave pulse control unit 11 transmits a pulse signal for the supply time T2 (seconds) to the microwave oscillator 12 every cycle T3 (seconds) according to the received “microwave pulse duty ratio (%)”. The microwave oscillator 12 generates a microwave pulse 38 having a supply time T2 (seconds) according to the received pulse signal at a period T3 (seconds) with a microwave power of 2.45 GHz corresponding to the supplied power, and isolators 17. , And supplied to the holder 9 and the workpiece 8 through the tuner 18, the waveguide 19, the coaxial waveguide 21, and the microwave supply port 22.

  As a result, the sheath layer along the surface of the work material 8 is expanded in the lateral direction of FIG. 1 by these negative bias voltages, and the plasma of the inert gas Ar and the source gas is generated by the microwave propagating in the sheath layer. To do. Then, the formation of the DLC film is started on the processing surface of the material 8 to be processed. When the film formation of the DLC film is started, the CPU 31 resets the measurement time of the end determination timer 36 to “0”, starts counting the film formation time of the DLC film, and proceeds to the process of S26. .

  In S <b> 26, the CPU 31 reads out the “deposition time (sec)” stored in the RAM 32 in S <b> 11, for example, 15 sec, and determines whether the measurement time of the end determination timer 36 has reached the DLC film formation time. A determination process for determining is executed. That is, the CPU 31 executes a determination process for determining whether or not to end the formation of the DLC film.

  If it is determined that the measurement time of the end determination timer 36 has not reached the “film formation time (sec)” (S26: NO), the CPU 31 determines that the measurement time of the end determination timer 36 is “film formation time”. Wait until time (sec) is reached.

  On the other hand, if it is determined that the measurement time of the end determination timer 36 has reached the “film formation time (sec)” (S26: YES), the CPU 31 sends a microwave oscillator to the microwave pulse controller 11 in S27. 12 transmits a stop signal instructing to stop the pulse signal being transmitted. Thereby, the microwave oscillator 12 stops the output of the microwave. In addition, the CPU 31 transmits a stop signal that instructs the negative voltage pulse generator 16 to stop applying the negative bias voltage. As a result, the negative voltage pulse generator 16 stops applying the negative bias voltage to the workpiece 8.

  Further, in S28, the CPU 31 outputs a stop signal that instructs the gas supply unit 5 to stop the supply of the inert gas Ar and the source gas. Thereafter, the CPU 31 transmits an exhaust signal that instructs the pressure adjusting valve 7 to fully open the exhaust. The pressure adjusting valve 7 is fully opened, and the raw material gas and the inert gas remaining in the processing container 2 are immediately exhausted by the vacuum pump 3. Thereafter, the CPU 31 instructs the pressure adjustment valve 7 to be fully closed. Further, the CPU 31 transmits a control signal instructing to fully open the atmosphere release valve 10 after the pressure adjustment valve 7 is fully closed. The air release valve 10 is fully opened, and the internal pressure of the processing container 2 is the same as the external pressure.

  Then, after stopping the vacuum pump 3, the CPU 31 forms a liquid crystal display (LCD) 30 on the basis of a signal from the vacuum gauge 26 when the pressure inside the processing container 2 becomes the same as the external pressure. It is displayed that the film is finished, and the film forming process is finished. Thereby, the work material 8 on which the DLC film is formed is taken out by the operator or the automatic transfer machine.

  In the first embodiment, a microwave 38 having a pulse frequency of 2500 Hz (period T3 = 1/2500 seconds) is used, and the supply time T2 for each pulse of the microwave 38 is a processing surface temperature of the workpiece 8 of 300. When the temperature is lower than or equal to ° C. (S22: YES), for example, it is set to 100 μsec. When the processing surface temperature of the workpiece 8 is higher than 300 ° C. (S22: NO), the supply time T2 for each pulse of the microwave is set to 200 μs, for example. At this time, the supply time T2 may be selected from a plurality of time candidates predetermined to be set such as 160 μsec, 200 μsec, 500 μsec, 1000 μsec, etc. in addition to 100 μsec. The supply time T2 is set to a time shorter than the period of the microwave pulse 38. Accordingly, the setting for setting the supply time T2 to 500 μs and 1000 μs can be selected when the pulse frequency is set to 500 Hz.

  In the microwave used in the first embodiment, the supply stop time (T3-T2) between continuous microwave pulses is set to 1 μsec or more. Here, in general, in the film forming apparatus, a time when the pulse output of the microwave is unstable occurs immediately after the rising of the microwave, and the pulse output is stabilized thereafter. The unstable period of the pulse output at the rising time is generally about 1 μsec. Therefore, it is desirable that the supply stop time between successive microwave pulses is 1 μsec or more. Thereby, generation of pulsed microwaves becomes intermittent, and generation of surface defects of the film can be suppressed and film quality can be improved.

  In consideration of the film formation flowchart shown in FIG. 6 and FIG. 7, when the film formation start temperature, which is the processing surface temperature of the material to be processed detected in S <b> 22, is 160 ° C., 200 ° C., and 300 ° C. Since the temperature is 300 ° C. or less, the supply time (PWS) per one pulse of the microwave that is determined as YES in S22 and selected in S23 is 2 μs, 10 μs, 25 μs, 50 μs, and 100 μs, respectively. A microwave set for one second is supplied to the workpiece 8 in S25 to perform film formation. Further, when the film formation start temperature is 400 ° C., the film formation start temperature is higher than 300 ° C. Therefore, it is determined NO in S22 and the supply time (PWL) per one pulse of the microwave selected in S24 However, for example, a microwave set at 500 μs is supplied to the material 8 to be processed in S25 to perform film formation.

  As described above, in the film forming apparatus 1 according to the first embodiment, the CPU 31 of the control unit 6 supplies the processed material 8 along the processed surface of the processed material 8 when the processed surface temperature is 300 ° C. or lower. The supply time per pulse of the pulsed microwave is controlled to be 100 μsec or less. At this time, even when the film formation start temperature is set low, since the supply time per pulse of the pulsed microwave is 100 μsec or less, defect growth in the film can be suppressed. In addition, since the supply of microwaves as a film formation energy source is interrupted at intervals of 100 μsec or less before film defect growth progresses in the film formation process, film defect growth is suppressed. Thus, the quality of the film can be improved. Therefore, the quality of the film can be improved. Further, since the microwave supply as the film formation energy source is interrupted in 100 μsec or less before the film defect growth proceeds in the film formation process, the film defect growth is suppressed. Can improve the quality.

  Further, the CPU 31 of the control unit 6 performs control so that the supply time per pulse of the pulsed microwave is 2 μsec or more. Generally, in a film forming apparatus, when a microwave rises, a pulse output unstable period of about 1 μsec generally occurs immediately after the rise, so that the supply time per pulse of the pulsed microwave should be 2 μsec or more. Thus, an unstable period of pulse output at the time of rising of the microwave can be eliminated. Thereby, the defect growth of the film can be suppressed and the film quality can be improved.

  Further, the CPU 31 of the control unit 6 performs control so that the supply time per pulse of the pulsed microwave is 50 μsec or less. Since the supply of microwaves as a film formation energy source is interrupted in 50 μsec or less before film defect growth proceeds in the film formation process, the film defect growth is further effectively suppressed. The quality of the film can be improved.

  Further, a radiation thermometer 29 for detecting the surface temperature of the work material 8 is provided. When the surface temperature of the work material 8 detected through the radiation thermometer 29 is 300 ° C. or lower, the CPU 31 of the control unit 6 Film formation is started under the control of supplying a microwave of 100 μsec per pulse. When the film formation start temperature is a relatively low temperature of 300 ° C. or less, surface defects of the film are likely to occur, but the supply time per pulse of the pulsed microwave is controlled to 100 μsec or less. By doing so, surface defects can be suppressed and the quality of the film can be improved.

  Further, since the microwave is supplied by the CPU 31 of the control unit 6 by setting the supply stop time per pulse of the pulsed microwave to 1 μsec or more, the generation of plasma by the pulsed microwave is intermittent. Thus, the generation of surface defects on the film can be suppressed and the quality of the film can be improved.

  Further, since the supply of the pulsed microwave and the application of the negative bias voltage are controlled by the CPU 31 of the control unit 6, the supply of the microwave is performed during the time when the pulsed microwave is supplied. The bias voltage applied from the negative voltage application units 15 and 16 is applied in synchronization with the. As a result, the generation of plasma covering the workpiece 8 becomes intermittent, thereby suppressing the generation of surface defects on the film and improving the quality of the film.

[Film Formation Processing of Second Embodiment]
Next, a film forming apparatus according to the second embodiment will be described. Here, the film forming apparatus according to the second embodiment basically has the same configuration as the film forming apparatus 1 according to the first embodiment described above, and is only different in a part of the film forming process program. It is. Therefore, in the following description, unlike the film forming process program executed in the film forming apparatus 1 of the first embodiment, the focus is on the specific film forming process executed by the film forming apparatus of the second embodiment. The same components will be described with the same reference numerals.

  The film forming process program executed in the film forming apparatus 1 according to the second embodiment executes the second film forming process shown in the flowchart of FIG. 10 instead of the film forming process of S200 shown in FIG. Program. The film forming program executed in the film forming apparatus 1 of the second embodiment is the same as S11 to S19 (see FIG. 6) in the flowchart executed by the film forming apparatus 1 of the first embodiment. Therefore, the description of the processing from S11 to S19 is omitted.

In FIG. 10, after the surface temperature of the processing surface of the material 8 to be processed, which is continuously calculated and output by the radiation thermometer 29 via the CPU 31 in S40, is acquired, the temperature increase rate K is continued in S41. The product (K × t) of (° C./μm) and the target film thickness t is based on the physical properties of the work material 8, the holder 9, etc. It is determined whether or not the difference ΔT (T _L −T ₀ ) is smaller than the processing surface temperature T ₀ of the workpiece 8 acquired in S40 from the limit temperature T _L determined in step S40. That is, it is determined whether K × t ≦ ΔT is satisfied. The temperature increase rate K, the target film thickness t, and the limit temperature _TL are preset in S31 and stored in the RAM 32.

  In S41, when the value of K × t is larger than ΔT (S41: NO), the processing surface temperature of the work material 8 is too high and ΔT is small. Until the surface temperature decreases, the acquisition of the surface temperature in step 40 is repeated. On the other hand, when the value of K × t is smaller than ΔT (S41: YES), the processing surface temperature of the work material 8 is sufficiently lowered, and the process proceeds to S42.

In S42, the processing surface temperature T ₀ of the work piece 8, which is acquired in S40 in immediately before it is determined whether a 300 ° C. or less. 300 ° C., the a temperature lower than the limit temperature T _L, reaches the limit temperature T _L is still temperature can afford.

When the processing surface temperature T ₀ of the workpiece 8 is 300 ° C. or lower (S42: YES), 100 μsec is selected as the supply time (PWS) per microwave pulse in S43. For example, after 100 μs (pulse frequency 2.5 kHz, duty ratio 25%) is selected, the process proceeds to S44.

  In S <b> 44, the CPU 31 reads the applied voltage value of “negative bias voltage (V)” from the RAM 32 and transmits it to the negative voltage power supply 15. The CPU 31 reads the supplied power value of “microwave output (kW)” from the RAM 32 and transmits it to the microwave power source 13. The CPU 31 reads from the RAM 32 the “negative bias voltage pulse duty ratio (%)”, the negative bias voltage period T3 (seconds), and the delay time T1 (seconds) from the supply start timing of one pulse of the microwave. The negative voltage pulse generator 16 transmits the negative voltage pulse. The CPU 31 reads out the “microwave pulse duty ratio (%)” and the period T3 (second) of one microwave pulse from the RAM 32 and transmits it to the microwave pulse control unit 11.

  As a result, the negative voltage power supply 15 supplies a negative applied voltage to the negative voltage pulse generator 16 according to the received applied voltage. The negative voltage pulse generator 16 receives the received “negative bias voltage pulse duty ratio, delayed by T1 (seconds) from the start of supplying the microwave pulse every cycle T3 (seconds) with the supplied negative applied voltage. A negative bias voltage of “(%)” is applied to the workpiece 8 via the negative voltage electrode 25 for (T4−T1) seconds.

  Further, the microwave power supply 13 supplies power to the microwave oscillator 12 according to the received microwave output power. The microwave pulse control unit 11 transmits a pulse signal for the supply time T2 (seconds) to the microwave oscillator 12 every cycle T3 (seconds) according to the received “microwave pulse duty ratio (%)”. The microwave oscillator 12 generates a microwave pulse 38 having a supply time T2 (second) (the supply time selected in S43) according to the received pulse signal for each cycle T3 (second) according to the supplied power. A 45 GHz microwave power is supplied to the holder 9 and the workpiece 8 through the isolator 17, the tuner 18, the waveguide 19, the coaxial waveguide 21 and the microwave supply port 22.

  As a result, the sheath layer along the surface of the material 8 to be processed by the negative bias voltage is expanded in the direction orthogonal to the propagation direction of the microwave, that is, in the lateral direction of FIG. 1, and propagates in the sheath layer. Plasma of the inert gas Ar is generated by the microwave. The propagation direction of the microwave is a direction perpendicular to the microwave introduction surface 22A in the vicinity of the microwave supply port 22. Since the microwave supplied from the microwave supply port 22 propagates along the sheath layer generated along the surface of the workpiece material 8, the propagation direction is a direction along the surface of the workpiece material 8.

  As a result, the sheath layer along the surface of the work material 8 is expanded in the lateral direction of FIG. 1 by the negative bias voltage, and the plasma of the inert gas Ar and the source gas is generated by the microwave propagating in the sheath layer. . Then, a DLC film is formed on the processing surface of the work material 8. When the deposition of the DLC film is started, the CPU 31 resets the measurement time of the end determination timer 36 to “0”, then starts counting the deposition time of the DLC film, and proceeds to the process of S45. .

On the other hand, when it is determined in S42 that the processing surface temperature T ₀ of the workpiece 8 is higher than 300 ° C. (S42: NO), the supply time per one pulse of the microwave is determined in S46. 500 microseconds is selected. For example, after 500 μs (pulse frequency 1.0 kHz, duty ratio 50%) is selected, the process proceeds to S47.

  In S47, as in S44, the CPU 31 reads the applied voltage value of “negative bias voltage (V)” from the RAM 32 and transmits it to the negative voltage power supply 15. The CPU 31 reads the supplied power value of “microwave output (kW)” from the RAM 32 and transmits it to the microwave power source 13. The CPU 31 reads from the RAM 32 the “negative bias voltage pulse duty ratio (%)”, the period T3 (seconds) of one pulse of the negative bias voltage, and the delay time T1 (seconds) from the microwave supply start timing, It transmits to the negative voltage pulse generation part 16. The CPU 31 reads out the “microwave pulse duty ratio (%)” and the period T3 (seconds) of the microwave pulse 38 from the RAM 32 and transmits them to the microwave pulse control unit 11.

  As a result, the negative voltage power supply 15 supplies a negative applied voltage to the negative voltage pulse generator 16 according to the received applied voltage. The negative voltage pulse generator 16 receives the received “negative bias voltage pulse duty ratio (T) (second) after a delay of T1 (seconds) from the start of microwave supply every cycle T3 (seconds). %) "Is applied to the workpiece 8 through the negative voltage electrode 25 for (T4-T1) seconds.

  Further, the microwave power supply 13 supplies power to the microwave oscillator 12 according to the received microwave output power. The microwave pulse control unit 11 transmits a pulse signal for the supply time T2 (seconds) to the microwave oscillator 12 every cycle T3 (seconds) according to the received “microwave pulse duty ratio (%)”. The microwave oscillator 12 generates a microwave pulse 38 having a supply time T2 (second) (the supply time selected in S46) according to the received pulse signal for each period T3 (second) according to the supplied power. A 45 GHz microwave power is supplied to the holder 9 and the workpiece 8 through the isolator 17, the tuner 18, the waveguide 19, the coaxial waveguide 21 and the microwave supply port 22.

  As a result, the sheath layer along the surface of the material 8 to be processed by these negative bias voltages is expanded in the direction orthogonal to the propagation direction of the microwave, that is, in the lateral direction of FIG. Plasma of the inert gas Ar is generated by the propagating microwave. The propagation direction of the microwave is a direction perpendicular to the microwave introduction surface 22A in the vicinity of the microwave supply port 22, but the microwave propagates along the sheath layer generated along the surface of the material 8 to be processed. Therefore, the propagation direction of the microwave is along the direction in which the work material 8 extends.

  As a result, the sheath layer along the surface of the work material 8 is expanded in the lateral direction of FIG. 1 by these negative bias voltages, and the plasma of the inert gas Ar and the source gas is generated by the microwave propagating in the sheath layer. To do. Then, the formation of the DLC film is started on the processing surface of the material 8 to be processed. When the deposition of the DLC film is started, the CPU 31 resets the measurement time of the end determination timer 36 to “0”, then starts counting the deposition time of the DLC film, and proceeds to the process of S45. .

In S45, the temperature of the material to be processed is acquired again, the processing surface temperature T ₀ of the work piece 8 obtained, it is determined whether greater than T _C. Here, T _C, in case of longer than 100μ seconds time for supplying microwaves is capable of suppressing temperature threshold surface defects of the membrane. For example, as described with reference to FIG. 8, when the processing surface temperature of the workpiece 8 is 400 ° C., the number of surface defects is not increased until 500 μs even if the microwave supply time is longer than 100 μs. since it is possible to suppress the 10 or so, T _C is set to, for example, 400 ° C. in a second embodiment.

The surface temperature _{T 0} of the work piece 8 is lower than the threshold value _{T C:} A (S45 YES), in S48, CPU 31 is stored in the RAM32 in S31 'deposition time (sec) ", for example, 15 seconds are read, and a determination process is performed to determine whether the measurement time of the end determination timer 36 has reached the DLC film formation time. That is, the CPU 31 executes a determination process for determining whether or not to end the formation of the DLC film.

  If it is determined that the measurement time of the end determination timer 36 has not reached the “film formation time (sec)” (S48: NO), the CPU 31 determines that the measurement time of the end determination timer 36 is “film formation time”. Wait until time (sec) is reached.

  On the other hand, when it is determined that the measurement time of the end determination timer 36 has reached the “film formation time (sec)” (S48: YES), the process proceeds to S53.

In contrast, in S45, the surface temperature _{T 0} of the work piece 8 is higher than the threshold value _{T C:} to (S45 NO) obtains a target NoboriAtsushiritsu K1 at S49. Here, the target temperature increase rate K1 is acquired by calculating (T _L −T ₁ ) / (t−t ₁ ). T _L is the limit temperature, T ₁ is the processing surface temperature of the workpiece 8 measured at the time of execution of the process of S45, t is the target film thickness, and t ₁ is the film formation speed and the elapsed time at the time of execution of the process of S45. It is the film thickness calculated and acquired from time.

  In S50, the microwave duty ratio corresponding to the acquired K1 is acquired with reference to the DLC film formation condition table 41 of FIG. 4 and the graph of FIG. For example, when the value of K1 is 68 ° C./μm, 50% is acquired as the microwave duty ratio corresponding to the value of K1. In S51, the duty ratio of the microwave used so far is changed to the duty ratio of the microwave acquired in S50.

  Thereafter, in S52, as in S48, the CPU 31 determines whether or not the formation of the DLC film has been completed. When film formation of the DLC film has not been completed yet (S52: NO), the CPU 31 waits until the measurement time of the termination determination timer 36 reaches “film formation time (sec)”.

  On the other hand, when it is determined that the measurement time of the end determination timer 36 has reached the “film formation time (sec)” (S52: YES), the process proceeds to S53. In S53, the CPU 31 transmits a stop signal instructing the microwave pulse control unit 11 to stop the pulse signal transmitted to the microwave oscillator 12. Thereby, the microwave oscillator 12 stops the output of the microwave. In addition, the CPU 31 transmits a stop signal that instructs the negative voltage pulse generator 16 to stop applying the negative bias voltage. As a result, the negative voltage pulse generator 16 stops applying the negative bias voltage to the workpiece 8.

  Further, in S54, the CPU 31 outputs a stop signal that instructs the gas supply unit 5 to stop the supply of the inert gas Ar and the source gas. This completes the film forming process. Thereafter, the CPU 31 transmits an exhaust signal that instructs the pressure adjusting valve 7 to fully open the exhaust. The pressure adjusting valve 7 is fully opened, and the raw material gas and the inert gas remaining in the processing container 2 are immediately exhausted by the vacuum pump 3. Thereafter, the CPU 31 instructs the pressure adjustment valve 7 to be fully closed. Further, the CPU 31 transmits a control signal instructing to fully open the atmosphere release valve 10 after the pressure adjustment valve 7 is fully closed. The air release valve 10 is fully opened, and the internal pressure of the processing container 2 is the same as the external pressure.

  Then, after stopping the vacuum pump 3, the CPU 31 forms a liquid crystal display (LCD) 30 on the basis of a signal from the vacuum gauge 26 when the pressure inside the processing container 2 becomes the same as the external pressure. It is displayed that the film is finished, and the film forming process is finished. Thereby, the work material 8 on which the DLC film is formed is taken out by the operator or the automatic transfer machine.

In the film forming apparatus 1 according to the second embodiment, it is determined whether or not the processing surface temperature T ₀ of the material to be processed 8 is 300 ° C. or lower in S 42 before starting the DLC film formation, and T ₀ is 300 ° C. or lower. In this case, the supply time per one pulse of the microwave is set to 100 μsec or less, and when _TL is higher than 300 ° C., the supply time per one pulse of the microwave is set to a time longer than 100 μsec. The point is the same as that of the film forming apparatus 1 of the first embodiment, but in S45 during film formation, it is determined whether or not the processing surface temperature T ₀ of the material 8 to be processed is larger than the threshold value T _C. If the temperature T ₀ is the threshold value T _C or acquires the target NoboriAtsushiritsu K1, running deposited by changing the duty ratio corresponding to the duty ratio of the microwave to the target NoboriAtsushiritsu K1 Yes.

  In the film forming apparatus 1 according to the second embodiment that executes the film forming control as described above, the film thickness of the DLC film can be formed to a target film thickness with higher accuracy.

  In addition, this invention is not limited to the said 1st Embodiment and 2nd Embodiment, Of course, various improvement and deformation | transformation are possible within the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Film-forming apparatus 2 Processing container 5 Gas supply part 6 Control part 8 Work material 9 Holder 11 Microwave pulse control part 12 Microwave oscillator 13 Microwave power supply 15 Negative voltage power supply 16 Negative voltage pulse generation part 17 Isolator 18 Tuner 19 Waveguide 21 Coaxial waveguide 22 Microwave supply port 25 Negative voltage electrode 27 Quartz window 29 Radiation thermometer 31 CPU
33 ROM
34 HDD

Claims (5)

A gas supply unit for supplying gas to a processing vessel provided with a work material having conductivity;
A microwave supply unit for supplying pulsed microwaves for generating plasma along the processing surface of the workpiece material;
A negative voltage application unit that applies a negative bias voltage to the workpiece material to expand a sheath layer along the processing surface of the workpiece material;
A microwave supply port for propagating the microwave supplied from the microwave supply unit to the expanded sheath layer;
The microwave supply unit, the in a period in which a negative bias voltage the material to be processed by the negative voltage application unit is applied, the to supply the microwaves pulsed supplied along the processing surface of the material to be processed a control unit for controlling so that,
A detection unit for detecting a surface temperature of the workpiece material;
Equipped with a,
When the surface temperature of the workpiece material detected through the detection unit is 300 ° C. or less, the control unit sets the supply time per one pulse of the microwave to be supplied to the microwave supply unit to 100 μs. A film forming apparatus that performs film formation under the following control . The control unit, the microwave supply unit, at an interval of the supply stop time than 1μ seconds between the pulsed microwave successive pulses, and characterized in that the control so as to supply the microwave The film forming apparatus according to claim 1 . Wherein the control unit includes a supply of the pulsed microwave by the microwave supply unit, the timing for the application of the negative bias voltage by the negative voltage application unit, to a control such Ru synchronized the deposition apparatus according to claim 1 or claim 2, characterized. A microwave supply unit for supplying a pulsed microwave to a conductive work material via a microwave supply port; a negative voltage application unit for applying a negative bias voltage to the work material; and the microwave A film forming method executed by a film forming apparatus comprising: a control unit that controls supply of the microwave by a supply unit; and a detection unit that detects a surface temperature of the material to be processed .
A negative voltage application step in which the negative voltage application unit applies a negative bias voltage to the work material to expand a sheath layer along the processing surface of the work material;
The control unit causes the microwave supply unit to generate plasma along the processing surface of the workpiece material during a period in which a negative bias voltage is applied to the workpiece material by the negative voltage application unit. by supplying the pulsed microwave, a microwave supply control step of controlling so as to propagate into said sheath layer is enlarged microwaves,
A temperature determination step for determining whether or not the surface temperature of the workpiece material detected via the detection unit is 300 ° C. or less;
With
When it is determined in the temperature determination step that the surface temperature of the workpiece material detected through the detection unit is 300 ° C. or less, in the microwave supply control step, the control unit by controlling the supply time per one pulse of the microwave to be supplied to the wave supply portion below 100μ seconds, film deposition method of. A microwave supply unit that supplies a pulsed microwave to a work material having conductivity via a microwave supply port, a negative voltage application unit that applies a negative bias voltage to the work material, and the work A detection unit that detects a surface temperature of the material, and the pulsed microwave supplied through the microwave supply port is expanded by a negative bias voltage applied by the negative voltage application unit. , said propagate into the sheath layer along the processing surface of the work piece, the computer controlling the film-forming apparatus for forming a film Thus,
A negative voltage application step of applying a negative bias voltage to the workpiece material to expand the sheath layer along the processing surface of the workpiece material in the negative voltage application section;
The pulsed micro for generating plasma along the processing surface of the workpiece material in a period in which a negative bias voltage is applied to the workpiece material by the negative voltage application unit in the microwave supply unit. A control process for controlling to supply a wave;
A temperature determination step for determining whether or not the surface temperature of the workpiece material detected via the detection unit is 300 ° C. or less;
A film forming program for causing the film forming apparatus to execute
When it is determined in the temperature determination step that the surface temperature of the material to be processed detected through the detection unit is 300 ° C. or less, the control unit supplies the microwave to the microwave supply unit in the control step. A film forming program which causes the film forming apparatus to execute so as to control a supply time per one pulse of a wave to 100 μsec or less .

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