JP5040066B2 - Film forming apparatus and film forming method - Google Patents

Description

  The present invention relates to a plasma CVD film-forming apparatus (hereinafter referred to as a film-forming apparatus) and a plasma CVD film-forming method (hereinafter referred to as a film-forming method), and in particular, stabilizes a thin film uniformly on a substrate surface under reduced pressure. The present invention relates to a film forming apparatus and a film forming method.

  Conventionally, in order to form a thin film on a substrate by plasma CVD, a method using capacitively coupled plasma and inductively coupled plasma is known (Non-Patent Document 1).

Plasma Electronics Ohmsha, edited by Hideo Sakurai, 1st edition, 1st edition, issued on August 25, 2000, page 106

  On page 106, line 8 of this document, it is described that capacitively coupled plasma can easily generate large-diameter plasma, which can be applied to substrates such as ceramics such as wafers and glass, resin plates, plastic films, metal plates, and metal foils. On the other hand, capacitively coupled plasma is widely used in the field of thin film formation.

  In this document, FIG. 6.3 and page 106, lines 13 to 14, when capacitively coupled plasma is used for thin film formation, two electrodes for plasma discharge are used. It arrange | positions on the sheet | seat of a sheet | seat, and film-forming is performed in this state.

  However, when a film is formed by such a method, there is a problem that, particularly by disposing a semiconductor or an insulating film-forming substrate on the electrode, it is difficult to flow plasma, that is, discharge impedance increases. there were. In this case, there is a problem that it is difficult to generate plasma discharge or the stability of plasma discharge is deteriorated.

  Further, when the discharge impedance increases, the discharge voltage increases and the discharge current decreases even when the same power is applied. As a result, film formation rate decreases (productivity decrease), film stress increases, damage to the substrate (electric charge-up occurs, poor adhesion due to strong etching of the substrate, substrate coloring occurs Etc.), and deterioration of film quality becomes a problem.

Furthermore, since the discharge impedance differs depending on the base material, there arises a problem that the film thickness and film quality of the formed film differ, and it is necessary to optimize the film forming conditions for each type of base material.
For example, when an insulating film such as SiO2 or TiO2 is formed, the discharge impedance is further increased due to the poor decomposability of the film forming material, and the film forming becomes unstable. is there.
On the other hand, there may be a problem that the film forming impedance is small. When the discharge impedance is small, the discharge voltage is small, the discharge current is large, the effect of ion implantation into the substrate is small, and as a result, the adhesion of the film is insufficient, and film peeling may occur.

  The present invention has been made in view of the above problems, and an object thereof is to provide a film forming apparatus and a film forming method capable of stably forming a uniform and high-quality thin film on the surface of a substrate. It is in.

In order to achieve the above-described object, a first invention is a film forming apparatus for forming a thin film on a substrate under reduced pressure by a plasma CVD method, and a chamber and a gas supply unit for supplying a gas into the chamber And a pair of electrodes disposed on the same surface side of the substrate in the chamber and placed at an electrically floating level, and one electrode and the other electrode are opposite between the two electrodes . And a power supply that supplies AC power having a frequency of 10 Hz to 27.12 MHz so as to have polarity, and a plasma generation apparatus that generates plasma between the pair of electrodes.
Here, the electrical floating level refers to the state in which the electrodes are designed and installed using insulating parts and insulating coatings so that insulation is maintained from chambers and film deposition equipment parts installed at the ground level. Means. Despite being designed so that the insulation of the electrode is ensured, the refrigerant required for cooling the electrode is used, and this refrigerant and the piping for circulating supply of the refrigerant have some conductivity The case where a resistance of 10 kΩ to 1000 MΩ is provided between the electrode and the ground based on the ground level (ground level) due to the above is also included in the present invention.
In this film forming apparatus, a plurality of sets of electrodes composed of the one set of electrodes may be installed on both sides of the substrate.
The power source is controlled by input power control or impedance control.

The electrode may include a magnet that concentrates and forms plasma near the substrate. The magnet has a horizontal magnetic flux density of 10 gauss to 10000 gauss on the substrate surface, and the magnet has a magnetron structure.
The power supply preferably has a frequency of 10 kHz to 27.12 MHz. The power source is controlled by input power control or impedance control.

The substrate may be installed at an electrical ground level or may be installed at an electrical floating level. Further, when the base material is at an electrically floating level, a constant DC voltage may be applied to the base material.
The gas supply unit is attached to the electrode side of the substrate and supplies gas toward the substrate surface. The gas supply unit is electrically at a floating level.

The chamber may have a film forming chamber and an exhaust chamber. It is desirable that the degree of vacuum in the exhaust chamber is higher in the range of 10 times or more and 10,000 times or less than the degree of vacuum at the time of film formation in the film forming chamber.
The film forming apparatus may further include a substrate transport mechanism. In this case, the substrate is placed on a substrate holding component such as an insulating tray or carrier. Further, the film forming apparatus may include a load lock chamber adjacent to the chamber.

A second invention is a film forming method in which a thin film is formed on a base material under reduced pressure by a plasma CVD method, wherein a gas is supplied into the chamber and disposed on the same surface side of the base material in the chamber. And supplying AC power having a frequency of 10 Hz to 27.12 MHz so that one electrode and the other electrode have opposite polarities to a pair of electrodes that are electrically installed at a floating level, In the film forming method, plasma is generated between the pair of electrodes to form a thin film on the substrate.

  According to the present invention, since the base material is not placed between the electrodes to form a film, it is not electrically coupled during plasma discharge, and it is possible to prevent an increase in discharge impedance. As a result, there is an advantage that plasma discharge is easily generated by reducing the discharge start voltage, and that stable plasma discharge is possible by reducing the discharge sustain voltage. In addition, since the discharge impedance does not increase, in plasma CVD film formation, the film formation speed is improved (productivity improvement), film stress is reduced, and damage to the base material is reduced (electric charge-up is suppressed, base material etching is performed). It is possible to improve adhesion and reduce base material coloring by reduction. Furthermore, since it is not necessary to consider the impedance variation due to the substrate, it is not necessary to optimize the film forming conditions for each type of substrate. Further, the size of the impedance can be adjusted as necessary depending on the arrangement and shape of the electrodes.

Hereinafter, a film forming apparatus and a film forming method according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a film forming apparatus 1 according to the first embodiment of the present invention. A film forming chamber 4 is formed in the chamber 3, and gas supply units 7-1, 7-2 and 7-3 are provided in the film forming chamber 4. The gas supply units 7-1, 7-2, and 7-3 are gas storage units 5-1, 5-2, 5- through the flow rate controllers 8-1, 8-2, and 8-3 for each supply gas type. 3 is connected. The gas reservoirs 5-1, 5-2, and 5-3 hold a film-forming gas. The gas reservoir 5-1 includes, for example, TEOS (tetraethoxysilane Si (OC ₂ H ₅₎ that is a film-forming raw material. ₄ ) is stored, the gas storage section 5-2 stores oxygen (O ₂ ) that is a decomposable oxidizing gas, and the gas storage section 5-3 stores argon (Ar) that is an ion gas for discharge. .

  In the chamber 3, a base material holder 11 is provided on the support portion 9, and a base material 13 is held on the base material holder 11. Although not shown, a temperature control medium pipe for circulating a coolant or a heat medium inside the substrate holder 11 and the support portion 9 is provided for the purpose of cooling or heating the substrate at the time of film formation to a constant temperature. It may be provided. Examples of the substrate 13 include a wafer, ceramics such as glass, a resin plate, a plastic film, a metal plate, a metal foil, paper, a nonwoven fabric, and a fiber.

  Electrode units 15-1 and 15-2 having electrodes 35-1 and 35-2 installed at a pair of electrically floating levels on the surface side of the base material 13 are installed. -2 is connected to a power source 17 capable of applying power at a constant frequency. Power is supplied from the power source 17 to emit plasma 16 toward the base material 13. The chamber 3 is provided with an evacuation pump 21 via a pressure adjustment valve 19.

2 is a side view of the electrode unit 15-1, and FIG. 3 is a view in the direction of arrow A in FIG.
An insulating shield plate 33 is provided on the support base 31, and an electrode 35 is provided on the insulating shield plate 33. The electrode 35 is provided with a power supply wiring 37, and a temperature control medium pipe 39 is provided inside the electrode 35. The same structure can be used for the electrode unit 15-2. In general, it is preferable to use the same size and the same structure for the electrodes and electrode units used as a set.

  The power supply wiring 37 is connected to the power source 17, and when the power is supplied from the power source 17, the plasma 16 is generated from the electrode 35. A temperature control medium such as cooling water flows inside the temperature control medium pipe 39 to cool the electrode 35 and the like.

  The gas supply units 7-1, 7-2, and 7-3 are arranged so that the jet ports thereof are directed to the surface of the base material 13. For this reason, the film-forming gas can be uniformly diffused and supplied to the surface of the base material 13, and uniform film formation can be performed on a large area portion of the base material 13.

The power supply 17 has a frequency of 10 Hz to 27.12 MHz. At a frequency of 10 Hz or higher, the decomposability of the film-forming raw material becomes good, and plasma discharge and film formation are possible. On the other hand, at a frequency higher than 27.12 MHz, the power supply and its matching circuit become expensive and the apparatus cost increases.
More preferably, 10 kHz to 500 kHz, 13.56 MHz, and 27.12 MHz are preferable.

  When a film-forming power source of 10 kHz to 500 kHz is used, the film-forming material is highly efficient in causing decomposition necessary for film formation, and a high-quality film is obtained because the film-forming material driving effect on the substrate 13 is high. It is done. Further, at 13.56 MHz and 27.12 MHz, the decomposition efficiency that causes decomposition necessary for film formation of the film formation material is further increased, the gas reactivity is increased, and high-quality film formation with high density and high adhesion becomes possible. . Since these power supplies are frequencies that are allowed to be used industrially even in the high frequency band, there are advantages that many such power supplies are commercially available and are inexpensive.

  As a control method of the power source 17, there is an impedance control method in which the input impedance control or the discharge impedance indicating the difficulty of the flow of electricity obtained by dividing the discharge voltage value by the discharge current value is used. In the input power control, the film formation input power of the power source 17 is made constant, and the film formation can be performed while stabilizing the plasma discharge, and the film formation can be performed stably, simply, and inexpensively.

  In the impedance control, when the response is fast and the impedance changes in the film formation for a long time (for example, the composition of the CVD film formation gas changes due to the influence of moisture that starts to be released when the inner wall of the chamber 3 is warmed by discharge). As a result, when the impedance changes), there is an effect of maintaining this constant.

  An optical method may be used as a control method for stable film formation of the power supply 17. For example, a plasma emission monitor may be installed, the emission intensity of a specific element in the plasma may be monitored, and process control for making the emission intensity constant may be performed. Process control methods in this case include control of the amount of supply gas such as film forming source gas, decomposable gas, oxidizing gas, discharge gas and ionized gas, control of the amount of film forming gas and additive gas, Film formation conditions such as film pressure and substrate temperature may be controlled.

The base material 13 may be installed at an electrical ground level. When the base material 13 is installed at the ground level, the charged charges accumulated on the surface of the base material 13 are transmitted to the base material holder 11 and released to the ground level, and as a result, stable film formation is possible.
In this case, it can be realized by using a metal conductive material for the substrate holder 11 or the holder support.

  Further, the base material 13 may be placed at an electrically floating level, that is, an insulation potential. By setting the potential of the base material 13 to a floating level, it is possible to prevent power leakage, increase the power for film formation, and increase the efficiency of use for film formation.

  Here, the electrical floating level means that the electrodes are designed and installed using insulating parts and insulating coating so that the insulating property is maintained from the chamber 3 and other film forming apparatus parts installed at the earth level. It means the state that is. Although the substrate holder 11 is designed to ensure insulation, a refrigerant or a heat medium necessary for cooling or heating the base material 13 and the substrate holder 11 is used. Due to the fact that the piping for circulating and supplying these media has some conductivity, a resistance of 10 kΩ to 1000 MΩ is provided between the base material 13 and the ground or the substrate holder 11 and the ground on the basis of the ground level (ground level). The case of having it is also included in the present invention.

Specifically, a method using an insulating material such as ceramic, mica, fluororesin, polyimide resin having insulating properties, plasma resistance and heat resistance for the substrate holder 11 or the substrate holder support, or a substrate holder , A method using a surface-treated material made of the ceramic, mica, fluororesin, polyimide resin on the surface of the substrate holder support, the insulating ceramics, mica, between the chamber 3 and the substrate holder 11, The method of inserting the member which consists of a fluororesin and a polyimide resin is mention | raise | lifted.
Ceramic materials include inorganic oxide films such as aluminum oxide and silicon oxide, inorganic nitride films such as aluminum nitride, silicon nitride, titanium nitride, and chromium nitride, aluminum oxynitride, silicon oxynitride, titanium oxynitride, and chromium oxynitride Such an inorganic oxynitride film is raised.

  The gas supply units 7-1, 7-2, and 7-3 may be electrically floating. In this case, it is possible to prevent the deposition power from leaking to the gas supply units 7-1, 7-2, 7-3, the deposition power can be increased, and the utilization efficiency for deposition is high. It will be a thing.

  Moreover, before the gas is supplied into the chamber 3 in the gas supply units 7-1, 7-2, and 7-3, it is possible to avoid film formation from occurring at the pipe supply port and blocking the supply port.

Next, a schematic operation of the film forming apparatus 1 will be described. The substrate 13 is placed on the substrate holder 11, the vacuum exhaust pump 21 is operated, the pressure adjustment valve 19 is opened, and the film forming chamber in the chamber 3 is evacuated. The film forming gas is supplied from the gas storage units 5-1, 5-2, and 5-3 while controlling the flow rate by the flow rate controllers 8-1, 8-2, and 8-3, respectively, and mixed uniformly. The gas is supplied to the gas supply units 7-1, 7-2, and 7-3 in the film chamber, and the film forming gas is jetted uniformly toward the base material 3. The opening degree of the pressure adjusting valve 19 is adjusted to set the desired degree of vacuum in the film forming chamber. Usually, in this plasma CVD film forming apparatus and film forming method, in order to stably form plasma and form a film having a desired sufficient density and adhesion, the film forming pressure ( The degree of vacuum) is adjusted by adjusting the opening degree of the pressure adjusting valve 19, and the film is formed while being set and maintained at a degree of vacuum between 0.1 Pa and 100 Pa.
Electric power is supplied from the power source 17 to the electrodes 35-1 and 35-2 at a constant frequency, plasma 16 is emitted from the electrodes 35-1 and 35-2 toward the base material 13, and a thin film is formed on the base material 13. The By-products generated during the film formation are exhausted by the vacuum exhaust pump 21.

  As described above, according to the first embodiment, the electrodes 35-1 and 35-2 are arranged on the same surface side of the substrate 13 and film formation is performed.

  According to the present invention, since the substrate is not deposited on the electrode and is not electrically coupled, an increase in the impedance of plasma discharge can be prevented, plasma can be easily formed, and a long time is required. It is possible to perform stable discharge and plasma CVD film formation. In addition, since the discharge impedance does not increase, in plasma CVD film formation, the film formation speed is improved (productivity improvement), the film stress is reduced, and damage to the base material is reduced (the occurrence of electrical charge-up is suppressed, the base material) It is possible to improve adhesion by reducing etching and reduce substrate coloring.

Furthermore, since it is not necessary to consider the impedance due to the substrate, it is not necessary to optimize the film formation conditions for each type of substrate.
Further, the size of the impedance can be adjusted as necessary depending on the arrangement and shape of the electrodes. Although the malfunction when discharge impedance becomes large previously was demonstrated, it may become a problem that film-forming impedance is small on the other hand. When the discharge impedance is small, the discharge voltage is small, the discharge current is large, the effect of ion implantation into the substrate is small, and as a result, the adhesion of the film is insufficient, and film peeling may occur. In such a case, specifically, the discharge impedance increases by increasing the distance between the electrode 35-1 and the electrode 35-2 installed in a pair. As a result, when the applied power is constant, the discharge voltage for film formation is large and the discharge current is small. As a result, the ion implantation effect is enhanced, and a film with high adhesion can be formed.
On the other hand, by reducing the distance between the electrode 35-1 and the electrode 35-2, the discharge impedance decreases, and when the applied power is constant, the discharge voltage is small and the discharge current is large, and the film formation rate is improved (productivity improvement). ), Reduction of film stress, and reduction of damage to the base material (suppression of occurrence of electrical charge-up, improvement of adhesion due to reduction of base material etching, reduction of base material coloring).
Thus, according to the present invention, it becomes possible to optimize the discharge impedance, adjust the ion implantation effect on the base material 13, increase the adhesion of the film, reduce the damage to the base material, and improve the quality. A film can be formed.

Next, a film forming apparatus 101 according to the second embodiment of the present invention will be described.
FIG. 4 shows a schematic configuration of the film forming apparatus 101. A partition wall 105 is provided in the chamber 103, and a film forming chamber 107 and an exhaust chamber 109 are formed by the partition wall 105.
The gas supply units 113-1, 113-2, and 113-3 are gas storage units 111-1, 111-2, and 111- for each supply gas type via the flow rate controllers 114-1, 114-2, and 114-3. 3 and a gas for film formation whose flow rate is individually controlled from 111-1, 111-2, and 111-3 are supplied from the gas reservoir.

The support portion 115 provided in the chamber 103 is provided with a coupling portion 117 made of an electrically insulative component, and a base material holder 119 is provided on the support portion 115. The substrate holder 119 supports the substrate 121.
In the chamber 103, electrode units 123-1 and 123-2 having electrodes 149-1 and 149-2 installed at an electrically floating level are provided. The electrodes 149-1 and 149-2 are connected to a power source 125. Connected.

  A vacuum exhaust pump 131-1 is provided on the exhaust chamber 109 side via a pressure adjustment valve 129-1, and a vacuum exhaust pump 131-2 is provided on the film formation chamber 107 side via a pressure adjustment valve 129-2.

5 is a side view of the electrode units 123-1 and 123-2, FIG. 6 is a view taken in the direction of the arrow B in FIG. 5, and FIG. 7 is a cross-sectional view taken along CC in FIG.
The magnet structure of the electrode units 123-1 and 123-2 is a magnetron structure. As shown in FIGS. 5, 6, and 7, an insulating spacer 142 and a base plate 143 are provided in the magnet case 141, and a magnet 145 is provided on the base plate 143. The magnet case 141 is provided with an insulating shield plate 147, and the electrode 149 is attached to the insulating shield plate 147. Therefore, the magnet case 141 and the electrode 149 are electrically insulated, and even if the magnet case 141 is installed and fixed in the chamber 103, the electrode 149 can be brought to an electrically floating level. A power supply wiring 151 is connected to the electrode 149, and the power supply wiring 151 is connected to a power source 125. In addition, a temperature adjusting medium pipe 153 for cooling the electrode 149 and the magnet 145 is provided inside the electrode 149.

In the film forming apparatus 101, a partition wall 105 is provided in a chamber 103, and the chamber 103 is divided into a film forming chamber 107 and an exhaust chamber 109. The pressures in the film formation chamber 107 and the exhaust chamber 109 are different. In order to stably form plasma in the film formation chamber 107 and form a film having a desired sufficient density and adhesion, the film formation pressure (degree of vacuum) in the film formation chamber is set to the pressure adjusting valve 131-2. By adjusting the degree of opening, the degree of vacuum between 0.1 Pa and 100 Pa is set and maintained, and film formation is performed. The exhaust chamber 109 is preferably 10 times or more and 10,000 times or less the degree of vacuum in the film formation chamber 107 during film formation.
In this way, by separating the film formation chamber 107 and the exhaust chamber 109, by-products generated during film formation can be efficiently exhausted from the vicinity of the surface of the substrate 121.
In order to exhaust the by-product efficiently, the exhaust chamber 109 needs to be at least 10 times higher in vacuum than the film formation chamber 107. Further, since an expensive exhaust system is required to make the vacuum degree of the exhaust chamber 109 10,000 times higher than that of the film forming chamber 107, it is preferably 10,000 times or less.

  As shown in FIGS. 6 and 7, the film forming apparatus 101 includes a magnet 145 on the back surface of the electrodes 149-1 and 149-2 inside the electrode units 123-1 and 123-2. The magnet 145 is installed so that plasma from the electrode 149 is concentrated on the surface of the substrate 121.

By providing the magnet 145, the reactivity in the vicinity of the surface of the substrate 121 is increased, and a high-quality film can be formed at high speed.
The magnets 145 of the electrode units 123-1 and 123-2 have a horizontal magnetic flux density at the surface position of the substrate 121 of 10 gauss to 10000 gauss. If the horizontal magnetic flux density on the surface of the base material 121 is 10 gauss or more, the reactivity near the surface of the base material 121 can be sufficiently increased, and a high-quality film can be formed at high speed.

On the other hand, an expensive magnet or a magnetic field generation mechanism is required to increase the horizontal magnetic flux density on the surface of the base material 121 to more than 10,000 Gauss.
The arrangement structure of the magnets 145 of the electrodes 123-1 and 123-2 is a magnetron structure. With the magnetron structure, ions and electrons formed during plasma CVD film formation continuously rotate according to the magnetron structure.

  For this reason, for example, even when performing plasma CVD film formation on a substrate 121 having a large area of 300 mm □ or more, over the entire surface of the electrode units 123-1 and 123-2, decomposition generation of film formation materials such as electrons and ions Even when the objects are uniformly diffused and the substrate 121 has a large area, uniform and stable film formation is possible.

In addition, since there is no accumulation of thermionic electrons and ions locally on the electrode unit 123 such as the electrode 149 and the magnet 145 and the heat resistance of the constituent members may be low, parts can be manufactured at low cost, It is possible to suppress the occurrence of defects such as perforations and cracks in the structure.
The electrodes 149, 149-1, and 149-2 are electrically conductive and have excellent plasma resistance for supplying power, have heat resistance, high cooling efficiency with cooling water (high thermal conductivity), and nonmagnetic materials Thus, it is preferable to use a material excellent in workability. Specifically, aluminum, copper, and stainless steel are preferably used.
The insulating shield plate 147 is preferably made of a material that is insulating, excellent in plasma resistance, heat resistant, and excellent in workability. Specifically, a fluororesin and a polyimide resin are preferably used.

  The potentials of the electrodes 149-1 and 149-2 and the base material 121 in the film formation apparatus 101 can be the same as those in the film formation apparatus 1.

Here, when the base material 121 is in an electrically floating level, a mechanism for applying a direct current potential to the base material 121 to enhance or weaken the effect of implanting the ionized film forming material onto the base material 121 may be installed. Is possible. In order to enhance the ionization implantation effect, it is preferable to apply a minus potential of minus 10 V to minus 3000 V to the base material 121, and in order to weaken the ionization implantation effect, a plus potential of plus 10 V to plus 3000 V is preferably imparted to the substrate 121. .
The coupling portion 117 is a mechanism necessary for applying a potential to the base material 121 in this way, and between the chamber 103, the base material 121, and the base material holder 119 in order to bring the base material holder 119 into an electrically floating level. It is an electrically insulating member installed in

  Moreover, although it becomes expensive expensive in terms of equipment, AC power having a frequency of 10 Hz to 27.12 MHz may be applied to the base material 121. In addition, you may perform in this Embodiment that direct current potential is applied to the base material 121 in this way.

Next, a film forming apparatus 201 according to the third embodiment of the present invention will be described.
FIG. 8 shows a film forming apparatus 201, in which electrodes 230-1, 230-2, 230-3, and 230-4 are arranged on both sides of the base material 213.

  Gas supply units 207-1, 207-2, 207-3, 207-4, 207-5, and 207-6 are provided in the chamber 203. The gas supply units 207-1, 207-2, and 207-3 are supplied to the gas storage units 205-1, 205-2, and 205- via the flow rate controllers 240-1, 240-2, and 240-3 for each supply gas type. The gas supply units 207-4, 207-5, and 207-6 are connected to the gas storage units 205-4 and 205 via the flow rate controllers 240-4, 240-5, and 240-6 for each supply gas type. -5, 205-6.

  The gas storage units 205-1, 205-2, 205-3, 205-4, 205-5, and 205-6 store a film forming gas. That is, the gas storage units 205-1, 205-2, and 205-3 correspond to the gas storage units 5-1, 5-2, and 5-3 in FIG. Similarly, the gas storage units 205-4, 205-5, and 205-6 correspond to the gas storage units 5-1, 5-2, and 5-3.

The base material 213 is held by the base material holder 211. Electrodes 230-1 and 230-2 are provided on one side of the substrate 213, and the electrodes 230-1 and 230-2 are connected to a power source 217-1.
In addition, electrodes 230-3 and 230-4 are provided on the opposite side of the substrate 213, and the electrodes 230-3 and 230-4 are connected to a power source 217-2.
The electrode surfaces of these electrodes 230-1, 230-2, 230-3, and 230-4 are electrically placed at a floating level.

Next, a schematic operation of the film forming apparatus 201 will be described.
The film forming gas stored in the gas storage units 205-1, 205-2, and 205-3 is individually adjusted in flow rate by the flow rate controllers 240-1, 240-2, and 240-3, and is supplied to the gas supply unit 207-. 1, 207-2, and 207-3 are emitted toward one side of the substrate 213. Power is supplied from the power source 217-1 to the electrodes 230-1 and 230-2, and plasma 216 is generated.

Similarly, the film forming gas is released from the gas supply units 207-4, 207-5, and 207-6 toward the opposite surface side of the substrate 213. In order to stably form plasma and to form a film having a desired sufficient density and adhesion, the opening pressure of the pressure adjusting valve 219 is adjusted to the film forming pressure (vacuum degree) in the film forming chamber in the chamber. Then, film formation is performed while maintaining the vacuum degree between 0.1 Pa and 100 Pa.
Power is supplied to the electrodes 230-3 and 230-4 from the power source 217-2, and plasma 216 is generated from the electrodes 230-3 and 230-4. Then, a thin film is formed on both surfaces of the base material 213. By-products during film formation are discharged from the vacuum exhaust pump 221.

  In the film forming apparatus 201, since one set of electrodes is provided on both sides of the base material 213, film formation on both surfaces of the base material 213 is possible, stress relaxation of the base material 213 is possible, and a high-quality thin film is formed. Can do.

Next, a film forming apparatus 301 according to a fourth embodiment of the present invention will be described.
FIG. 9 is a view showing the film forming apparatus 301. A partition wall 305 is provided in the chamber 303, and a film formation chamber 307 and an exhaust chamber 309 are formed in the chamber 303.

  Gas supply sections 313-1, 313-2, and 313-3 are provided in the chamber 303. The gas supply units 313-1, 313-2, and 313-3 are gas storage units 311-1, 311-2, and 311 via the flow rate controllers 314-1, 314-2, and 314-3 for each supply gas type. -3. The gas storage units 311-1, 311-2, and 311-3 store a film forming gas.

  Electrodes 360-1 and 360-2 are provided in the chamber 303 as an electrical floating level, and the electrodes 360-1 and 360-2 are connected to a power source 325.

  A rail 357 for running the tray 319 is provided in the chamber 303. A vacuum exhaust pump 331-1 is provided on the exhaust chamber 309 side via a pressure adjustment valve 329-1, and a vacuum exhaust pump 331-2 is provided on the film formation chamber 307 side via a pressure adjustment valve 329-2.

The vacuum exhaust pump 331-1 exhausts the exhaust chamber 309. The vacuum exhaust pump 331-2 exhausts the film formation chamber 307 side.
A load lock chamber (preliminary exhaust chamber) 351-1 is provided in the chamber 303 via a gate valve 341-1. A vacuum exhaust pump 355-1 is provided in the load lock chamber 351-1 via a pressure adjustment valve 353-1.

In addition, a load lock chamber (preliminary exhaust chamber) 351-2 is provided in the chamber 303 via a gate valve 341-2. A vacuum exhaust pump 355-2 is provided in the load lock chamber 351-2 via a pressure adjustment valve 353-2.
By providing these load lock chambers 351-1 and 351-2, the vacuum inside the chamber 303 having the film forming portion is continuously returned to the atmospheric pressure when the substrate is taken into and out of the atmosphere. A film forming process can be performed. As a result, an apparatus with high productivity can be obtained and a high degree of vacuum can be maintained, so that moisture adsorption can be prevented inside the chamber 303, and advantages such as a good quality film can be obtained.

The functions of the gas supply unit 313, the electrode 360, and the like in the chamber 303 are the same as those in the first embodiment.
The gate valve 341-1 opens and closes between the chamber 303 and the load lock chamber 351-1. The gate valve 341-2 opens and closes between the chamber 303 and the load lock chamber 351-2.

The load lock chamber 351-1 is provided with a tray transporting and moving mechanism so that a plurality of base materials can be stocked. A large number of trays 319 on which the base material 321 is placed are provided, and these trays 319 can be stored in a storage rack having an up / down function. The vacuum exhaust pump 351-1 exhausts the load lock chamber 351-1. The gate valve 341-1 can be opened and closed in a state where the degree of vacuum in the load lock chamber 351-1 is substantially equal to the degree of vacuum in the chamber 303 and there is no pressure difference.
A tray 319 runs on a rail 357 in the chamber 303.

  The gate valve 341-2 opens and closes between the chamber 303 and the load lock chamber 351-2. The load lock chamber 351-2 can store a large number of trays 319, and the trays 319 can move in the vertical direction. The vacuum exhaust pump 355-2 exhausts the load lock chamber 351-2.

Next, the schematic operation of the film forming apparatus 301 will be described.
The inside of the chamber 303 having the film formation chamber 307 and the exhaust chamber 309 is continuously exhausted by the vacuum exhaust pumps 331-1 and 331-2, and a desired degree of vacuum is achieved by the pressure adjustment valve 331-1 and the pressure adjustment valve 331-2. Set to

  In the atmosphere, the tray 319 on which the base material 321 is placed is set in the load lock chamber 351-1. Subsequently, the evacuation pump 355-1 is operated to open the pressure adjustment valve 353-1 to evacuate the load lock chamber 351-1. After the degree of vacuum of the load lock chamber 351-1 becomes the same as the degree of vacuum of the chamber 303 including the film formation chamber 307, the gate valve 341-1 can be opened. After the tray 319 travels on the rail 357 and the entire tray 319 passes through the gate valve 341-1 and is transported to the chamber 303, the gate valve 341-1 is closed.

After the gate valve 341-1 is closed, the film forming gas stored in the gas storage units 311-1, 311-2, 311-3 are individually provided flow rate controllers 314-1, 314-2, A desired flow rate is supplied by 314-3, these gases are uniformly mixed in advance, and are ejected from the gas supply units 313-1, 313-2, and 313-3 toward the substrate 321 side. The film formation chamber 307 and the exhaust chamber 309 are set to pressures suitable for film formation by the vacuum exhaust pumps 331-1 and 331-2 and the pressure adjusting valves 329-1 and 329-2. In the exhaust chamber 309, film formation is performed at a higher degree of vacuum in the range of 10 times to 10000 times that of the film formation chamber 307.
The tray 319 runs on the rail 357 in the chamber 303 and reaches a position below the electrodes 360-1 and 360-2. The tray 319 may stop at the electrodes 360-1 and 360-2, or may pass through while traveling at a constant speed. In addition, in order to obtain a required film thickness, the tray 319 may be repeatedly formed by bidirectional transfer.
In order to stably form plasma and form a film having a desired sufficient density and adhesion, the film formation pressure (vacuum degree) in the film formation chamber in the chamber is the opening of the pressure adjustment valve 329-1. In order to perform film formation while maintaining the vacuum degree between 0.1 Pa and 100 Pa, and to efficiently exhaust the by-products generated on the substrate surface during the film formation, The pressure (degree of vacuum) is adjusted by adjusting the opening of the pressure adjustment valve 329-2, and the film is formed while being set and maintained at a degree of vacuum 10 to 10,000 times higher than the film forming chamber pressure.

  At this time, power is supplied from the power source 325 to the electrodes 360-1 and 360-2, and plasma is generated from the electrodes 360-1 and 360-2. Then, a thin film is formed on the base material 321. After the thin film is formed, the supply of power supplied to the electrodes 360-1 and 360-2 is stopped, and the plasma discharge is stopped. Further, the film forming gas supply is stopped, and the pressure adjusting valves 329-1 and 329-2 are fully opened to exhaust the residual gas in the chamber 303.

  Either the load lock chamber 351-1 or 351-2 can be used as a part for re-storing the film formation substrate. Here, the case of re-storing in the load lock chamber 351-2 will be described. In advance, a space for re-storing the film formation substrate is made in the load lock 351-2 chamber, the vacuum exhaust pump 355-2 is operated, the pressure adjustment valve 353-2 is fully opened, and the load lock chamber 351-. 2 Depressurize the inside.

  After the film formation process described above is completed and the residual gas is exhausted, the vacuum degree of the chamber 303 and the vacuum degree of the load lock chamber 351-2 are made the same, then the gate valve 341-2 is opened, and the substrate tray 319 and the deposition target substrate are transported on the rail 357 and moved to a predetermined position in the load lock chamber 351-2. After the substrate tray 319 passes through the gate valve 341-2 and the whole moves to the load lock chamber 351-2, the gate valve 341-2 is closed.

  It is also possible to continuously perform the above steps on a plurality of base materials 321. Further, after the film forming process is completed for all the base materials 321, the base material can be taken out by stopping the evacuation of the load lock chamber 351-2 and releasing it to the atmosphere.

  According to the fourth embodiment, since at least one load lock chamber 351-1 (or 351-2) is provided before and after the chamber 303, the evacuation process and the film formation process can be separated, and productivity is increased. Will improve.

In addition, since the tray 319 with wheels transports the base material 321 while traveling on the rail 357, productivity is improved, and uniform and stable continuous film formation on a large area portion of the base material 321 becomes possible.
In addition, as a base material transport mechanism, the tray 319 with wheels is transported on the rail 357, the end portion of the base material is held by a nail, the arm moving structure and the base material are loaded on the tray or the frame, and the whole is A mechanism that moves with an arm can also be used.

  Note that the surface of the tray 319 is preferably insulative, and the base member 321 is preferably at an electrically floating level. By making the tray 319 insulative, leakage of electric power can be prevented, the electric power used for film formation can be increased, the utilization efficiency for film formation is high, and stable film formation is possible.

  As described above, each embodiment according to the present invention has been described. In the second to fourth embodiments, the functions of the gas storage unit, the gas supply unit, the power source, the electrode, and the like are the same as those in the first embodiment. It is the same as the form. The power supply voltage, the power supply control method, the potential of the base material, the potential of the gas supply unit, etc. may be the same as in the first embodiment. Further, the electrodes shown in FIGS. 2 and 3 and those shown in FIGS. 5, 6, and 7 may be used as appropriate.

Next, experimental results when films are actually formed using the film forming apparatus 101 shown in FIG. 4 and the film forming apparatus 401 as a comparative example shown in FIG. 10 will be described.
In the film forming apparatus 101 shown in FIG. 4, as described above, the magnets 145 having the magnetron structure shown in FIGS. The magnetic flux density was set to 1000 gauss. The chamber 103 was set to the ground level, and the base material holder 119 was set to the electrically floating level as a structure through Teflon (registered trademark) resin.

  An aqueous ethylene glycol solution having a concentration of 30% was supplied to the cooling water pipe 153 as a refrigerant. That is, the coolant was individually circulated and supplied to the substrate holder 119 and the electrodes 123-1 and 123-2, and the substrate holder 119 was cooled to 0 degrees. At this time, the resistance between the electrode 123-1 and the substrate holder 119, between the electrode 123-2 and the substrate holder 119, and between the electrode 123-1 and the electrode 123-2 was 1 MΩ.

A silicon wafer was prepared as the substrate 121 and set on the substrate holder 119. Both the film formation chamber 107 and the exhaust chamber 109 were evacuated to 1 × 10 ⁻⁴ Pa from the vacuum exhaust pumps 131-1 and 131-2. TEOS (tetraethoxysilane Si (OC ₂ H ₅ ) ₄ ) as a film forming gas was vaporized at a heating temperature of 120 ° C. and supplied in a gas state. Then, TEOS, oxygen, and argon are supplied at 20 sccm, 500 sccm, and 200 sccm, respectively, while controlling the flow rate using a flow controller (mass flow controller), mixed uniformly, and then supplied as a shower onto the base material 121. did.

  Next, the vacuum exhaust pumps 131-1 and 131-2 were adjusted so that the pressure in the film formation chamber 107 was 10 Pa and the pressure in the exhaust chamber 109 was a constant pressure of 0.5 Pa. Using a power supply with a frequency of 40 kHz as the power supply 125 (manufactured by Advanced Energy Industries Inc., PEII 10 kW), 3 kW of power is applied to the electrodes 123-1 and 123-2 by the power control method, and film formation is performed in 5 minutes. went. During this time, the average discharge voltage was 525V. Further, as a result of visually counting the number of occurrences of discharge arcing (abnormal discharge), it was found that the occurrence was zero and there was no abnormal discharge, and stable film formation was possible.

After film formation, the residual gas in the chamber 103 is exhausted, the base material 121 is taken out, and the film thickness and refraction of the SiO ₂ film formed on the wafer base material using a spectroscopic ellipsometry apparatus (JOBIN YVON, UVISEL). When the refractive index was measured, the refractive index at a film thickness of 315 nm and 633 nm was a dense film of 1.46.
FIG. 11 shows the result of performing this film formation five times in succession. As shown in FIG. 11, it was found that a highly reproducible result was obtained and stable film formation was possible.

On the other hand, a film forming apparatus 401 shown in FIG. 10 was prepared as a comparative example. Compared with the film forming apparatus 101 shown in FIG. 4, the film forming apparatus 401 has one side of the power supply 125 connected to the base material holder 119 side, and the electrodes 123-1 and 123-2 are electrically connected to the same potential. The resistance between the electrodes 123-1 and 123-2 was 0.1Ω.
Except for these, the film formation was performed in the same setting procedure as the apparatus shown in FIG. FIG. 12 is a diagram showing a film formation result.

  Comparing FIG. 11 and FIG. 12, in the film forming apparatus 101 according to the present invention shown in FIG. 4, the discharge voltage is reduced, the discharge is easily stabilized, and arcing during the discharge hardly occurs, and a good quality and uniform film. Can be formed. In addition, since the input electric power is effectively used for film formation, the film formation speed is improved, and a high-quality film having a high refractive index, that is, a high density is formed.

  The preferred embodiments of the information providing system and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

The figure which shows the structure of the film-forming apparatus 1 which concerns on the 1st Embodiment of this invention. Side view of electrode 15-1 A direction arrow view of FIG. The figure which shows the structure of the film-forming apparatus 101 which concerns on 2nd Embodiment. Side view of electrode 123-1 B direction arrow view of FIG. CC sectional view of FIG. The figure which shows the structure of the film-forming apparatus 201 which concerns on 3rd Embodiment. The figure which shows the structure of the film-forming apparatus 301 which concerns on 4th Embodiment. The figure which shows the structure of the film-forming apparatus 401 used as a comparative example The figure which shows the film-forming result by the film-forming apparatus 101 The figure which shows the film-forming result by the film-forming apparatus 401

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 101, 201, 301 ......... Film-forming apparatus 3, 103, 203, 303 ......... Chamber 5, 111, 205, 311 ...... Gas storage part 7, 113, 207, 313 ... Gas supply part 8 114, 240, 314 ............ Flow controller 13, 121, 213, 321 ......... Base material 15, 123, 215, 323 ......... Electrode unit 17, 125, 217, 325 ......... Power source 35, 149, 230, 360 ......... Electrodes

Claims (18)

A film forming apparatus for forming a thin film on a substrate under reduced pressure by a plasma CVD method,
A chamber;
A gas supply unit for supplying gas into the chamber;
In the chamber, a set of electrodes disposed on the same surface side of the base material and installed at an electrically floating level;
A power source for supplying AC power having a frequency of 10 Hz to 27.12 MHz so that one electrode and the other electrode have opposite polarities between the two electrodes;
Comprising
A film forming apparatus, wherein plasma is generated between the pair of electrodes.   The film forming apparatus according to claim 1, wherein a plurality of sets of electrodes including the one set of electrodes are disposed on both sides of the substrate.   The film forming apparatus according to claim 1, wherein the electrode includes a magnet that concentrates and forms plasma in the vicinity of the substrate.   4. The film forming apparatus according to claim 3, wherein the magnet has a horizontal magnetic flux density on the surface of the substrate of 10 to 10,000 gauss.   The film forming apparatus according to claim 3, wherein the magnet has a magnetron structure.   The film forming apparatus according to claim 1, wherein the power source has a frequency of 10 kHz to 27.12 MHz.   The film forming apparatus according to claim 1, wherein the power source is input power controlled.   The film forming apparatus according to claim 1, wherein the power source is impedance-controlled.   The film forming apparatus according to claim 1, wherein the base material is electrically installed at a ground level.   The film forming apparatus according to claim 1, wherein the substrate is placed at an electrically floating level.   The film forming apparatus according to claim 1, wherein the gas supply unit is attached to the electrode side of the substrate and supplies gas toward the surface of the substrate.   The film forming apparatus according to claim 1, wherein the gas supply unit is electrically at a floating level.   The film forming apparatus according to claim 1, wherein the chamber includes a film forming chamber and an exhaust chamber. 14. The film forming apparatus according to claim 13 , wherein the degree of vacuum in the exhaust chamber is not less than 10 times and not more than 10,000 times the degree of vacuum at the time of film formation in the film forming chamber.   The film forming apparatus according to claim 1, further comprising a base material transport mechanism. The film forming apparatus according to claim 15 , wherein the substrate is placed on an insulating substrate holding component. The film forming apparatus according to claim 15, further comprising a load lock chamber adjacent to the chamber. A film forming method for forming a thin film on a substrate under reduced pressure by a plasma CVD method,
Supplying gas into the chamber,
In the chamber , a frequency of 10 Hz is set so that one electrode and the other electrode have opposite polarities to a pair of electrodes disposed on the same surface side of the base material and placed at an electrically floating level. Supply alternating current power of ~ 27.12 MHz to generate plasma between the set of electrodes;
A film forming method comprising forming a thin film on the substrate.

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