JP3774353B2 - Method and apparatus for forming metal compound thin film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a metal compound thin film and an apparatus for forming the same, and more particularly to a method for forming a metal compound thin film on a substrate stably and at high speed by a sputtering method and an apparatus for forming the same.
[0002]
[Prior art]
Forming thin films of metal compounds such as oxides, nitrides, and fluorides by sputtering is widely performed. There are the following typical methods for forming thin films of these metal compounds.
1. Using a radio frequency (RF) power source, a reactive gas (eg, oxygen, nitrogen, fluorine gas) is introduced into a metal compound target (insulating) or metal target (conductive), and a thin film is formed by reactive sputtering. Method (hereinafter referred to as RF reactive sputtering method).
2. A method of forming a thin film by reactive sputtering by introducing a reactive gas (for example, oxygen, nitrogen, fluorine gas) into a metal target (conductive) using a direct current (DC) power source (hereinafter referred to as DC reactive sputtering method). Called).
These methods are the most commonly used methods for forming a metal compound thin film.
[0003]
However, these methods have a problem that the deposition rate of the thin film is slow as shown in FIG. Here, FIG. 10 is a diagram showing the relationship between the deposition rate (thin film formation rate) and the reactive gas flow rate / total gas flow rate ratio. The reactive gas flow rate and the total gas flow rate refer to respective gas flow rates in the vicinity of the target.
The RF and DC reactive sputtering method, which introduces a reactive gas into the region where the target is disposed, corresponds to the D region of the graph, and the deposition rate is lower than when the flow rate ratio of the reactive gas is small. I understand.
For example, the deposition rate of the metal compound thin film by the RF and DC reactive sputtering method is 1/5 to 1/10 as compared with the rate when the metal thin film is deposited by sputtering. Further, the deposition rate of the metal compound thin film by the RF or DC reactive sputtering method is about 1/2 to 1/10 compared with the vacuum deposition by the ion beam heating method or the resistance heating method. Therefore, the RF and DC reactive sputtering method has a problem in mass production.
[0004]
Therefore, in order to increase the film forming rate, the amount of reactive gas (for example, oxygen, nitrogen, fluorine gas) to be introduced can be reduced in the RF and DC reactive sputtering method.
However, if the amount of reactive gas to be introduced (for example, oxygen, nitrogen, fluorine gas) is reduced, there is a problem that an incomplete metal compound thin film in which constituent elements such as oxygen, nitrogen, and fluorine are deficient tends to be formed.
[0005]
For example, SiO, which is a typical oxide thin film used for optical films, insulating films, protective films, etc. ₂ To create a thin film, use SiO ₂ RF reactive magnetron sputtering is performed using a target (insulating) and a high frequency power source, or oxygen gas is introduced using a DC power source using a silicon (Si) target (conductive), It is common to perform DC reactive magnetron sputtering.
At this time, if the oxygen gas that is a reactive gas introduced simultaneously with the sputtering working gas (for example, argon gas) is insufficient, the composition of the thin film to be formed is SiO 2. _x (X <2).
[0006]
Further, the RF and DC reactive sputtering method has a problem that arc discharge (abnormal discharge) is likely to occur.
This arc discharge causes the following problems.
1. The target material scatters on the substrate, causing defects in the thin film being formed.
2. An arc mark remains on the surface of the target, and an insulating portion around the arc mark is SiO. ₂ Accumulation continues, and further abnormal discharge occurs.
[0007]
Here, the mechanism of occurrence of arc discharge (abnormal discharge) in the target is as follows.
That is, in the RF and DC reactive sputtering method, the reactive gas introduced into the region where the target is disposed reacts on the surface of the target, and SiO 2 ₂ Form. This SiO ₂ In addition, accumulation of charges of plasma argon ions and oxygen ions occurs. A large amount of this positively charged charge accumulates on the target surface. This charge is SiO ₂ Breakdown occurs when the insulation limit of the film is exceeded. This electric charge causes an arc discharge to the conductive part of the target, the earth shield (anode). When arcing occurs, the accumulated charge escapes from the target surface.
[0008]
In RF and DC reactive sputtering, since film formation is usually performed using plasma, component parts of the apparatus, a substrate holder, a substrate, and the like are heated by collision of charged particles (ions, electrons). . Therefore, it is difficult to perform sputtering at 100 ° C. or lower, and there is a problem that it is difficult to form a film on a material having low heat resistance such as plastic. This problem is particularly noticeable in RF magnetron sputtering using a high-frequency power source, and it is desired to develop a method capable of performing sputtering at a low temperature.
[0009]
Therefore, in order to solve the above problems, a new metal compound thin film forming method by sputtering called a drum rotating metal mode (for example, Meta Mode) and twin magnetron sputtering has been developed in recent years.
The drum rotation type metal mode (for example, Meta Mode) is a film forming chamber provided with a target and a plasma generating means outside a cylindrical substrate holder disposed in a vacuum vessel, a reactive gas introducing means, Using a device provided separately from a reaction chamber provided with plasma generating means, rotating a substrate holder, depositing an ultrathin metal film on the substrate by sputtering in the film formation chamber, and reactive gas in the reaction chamber Is a method of repeatedly converting a metal ultrathin film into a metal compound by plasma generated by introducing. Unlike RF and DC reactive sputtering, this method does not introduce a reactive gas into the deposition chamber where the target is placed, so arc discharge is unlikely to occur and metal compound thin films can be deposited at high speed. It is.
That is, when sputtering is performed using this drum-rotating metal mode (for example, Meta Mode), the relationship between the deposition rate (thin film formation rate) and the reactive gas flow rate / total gas flow rate ratio is shown in FIG. Corresponding to (reactive gas flow rate / total gas flow rate ratio = 0%), compared with the above-mentioned RF reactive sputtering method and DC reactive sputtering method (region D), which are most often used in the past, oxide thin films, etc. It is possible to perform the film formation at a high speed.
[0010]
Twin magnetron sputtering is a kind of dual magnetron sputtering.
Here, dual magnetron sputtering means that one target is always a cathode (minus) by applying an alternating voltage alternately to plus and minus to a pair of the same or different targets electrically insulated from the ground potential. This is a method in which magnetron sputtering is performed while introducing a reactive gas so that the other target is an anode (plus electrode).
[0011]
In this dual magnetron sputtering, one of a pair of sputtering targets is a cathode and the other is an anode, and sputtering is performed by alternately changing both targets to an anode and a cathode by an alternating electric field. Is converted to the cathode, the incomplete reactant metal adhering to the target surface at the time of the anode is sputtered to the original normal state. Therefore, a stable anode potential state is always obtained, a change in plasma potential (usually almost equal to the anode potential) can be prevented, high-speed film formation of an oxide thin film, etc., and arc discharge can be prevented.
In other words, in the conventional RF and DC reaction magnetron sputtering method, the target shield, device parts, and device body serving as the anode are covered with non-conductive or low-conductive incomplete metal to prevent the anode potential from being lowered. It can be done.
[0012]
As described above, twin magnetron sputtering is a kind of the dual magnetron sputtering. In twin magnetron sputtering, an insulator is used for the non-erosion part of the target, an AC voltage is applied to the sputtering electrode from the power supply for sputtering, and an AC voltage with a frequency much higher than the sputtering voltage is applied from the oscillation circuit. This is characterized in that the sputtering voltage is feedback-controlled by the reactive gas flow rate / total gas flow rate ratio in the vicinity of the target, and the film formation rate is controlled by this voltage.
By using an insulator in the non-erosion portion of the target, arc generation is reduced. The oscillation circuit oscillates when an arc is generated due to charge accumulation, generates an additional polarity alternation of the cathode, and extinguishes the arc.
[0013]
Further, feedback control will be described. Since there is a correlation between the sputtering voltage and the film formation speed, the film formation speed can be controlled by using the voltage as a parameter for film formation speed control. Since the voltage serving as the parameter and the reactive gas flow rate / total gas flow rate ratio are substantially the same as the relationship between the deposition rate and the reactive gas flow rate / total gas flow rate ratio in FIG. The voltage value can be feedback controlled by the flow rate of the reactive gas. Therefore, in this twin magnetron sputtering, the film formation rate is adjusted to a desired value by adjusting the reactive gas flow rate and using the voltage value as a parameter.
[0014]
This twin magnetron sputtering is a method for compensating for the respective problems of the metal compound thin film forming methods using the metal mode and the compound mode. That is, according to this method, the compound thin film can be directly deposited on the substrate in the transition region between the metal mode and the compound mode (region C in FIG. 10), and abnormal discharge is reduced. Compared with the RF reactive sputtering method and the DC reactive sputtering method (region D), which have been most often used in the past, stable film formation at high speed is possible.
Twin magnetron sputtering has also been reported, for example, in JP-A-4-325680, JP-A-5-222531, and Japanese Patent No. 2574636.
[0015]
However, in the drum-rotating metal mode (for example, Meta Mode) and twin magnetron sputtering, a strong stress is generated in the formed metal compound thin film, and it is difficult to reduce optical absorption of the thin film. There is. In conventional twin magnetron sputtering, when a metal compound is deposited, a reactive gas is introduced into a vacuum vessel in which a pair of targets are arranged. According to this method, abnormal discharge is prevented. Insufficient reactive gas can be introduced into the vicinity of the target, so oxygen as the reactive gas becomes insufficient, and the composition of the thin film becomes SiO 2 _x There is a problem that the reaction product becomes incomplete as in (x <2).
[0016]
[Problems to be solved by the invention]
The present invention solves the respective problems of the above-described conventional sputtering film forming methods, and the object of the present invention is to form a metal compound thin film having stable characteristics free from incomplete metal reactant at high speed. An object of the present invention is to provide a method of forming a metal compound thin film and an apparatus for forming the same.
Another object of the present invention is to provide a metal compound thin film forming method and apparatus for forming a metal compound thin film capable of forming a high quality metal compound thin film with less stress and less optical absorption at high speed. is there.
[0017]
According to the first aspect of the present invention, according to the first aspect of the present invention, a plurality of sputtering targets that are electrically insulated from the ground potential, each target alternately turns into a cathode and an anode, and at the same time, one of the targets always becomes a cathode. AC voltage is applied so that the target becomes the anode, true In the film formation process zone in the empty tank, the inert gas and the total gas flow rate of the film formation process zone More than 3% Reactive gas with a flow rate of 20% or less , By gas introduction means for introducing into the film forming process zone through piping connected in the film forming process zone Introducing a metal incomplete reactant ultrathin film composed of incomplete metal reactants on a substrate, and a reaction process spatially and pressure-separated from the film formation process zone in the vacuum chamber In the zone, an active species of an electrically neutral reactive gas is brought into contact with the metal incomplete reactant ultrathin film, and the metal incomplete reactant reactant ultrathin and the reactive species of the reactive gas are reacted to form a metal. A plurality of layers of the metal compound ultrathin film are formed by sequentially converting the step of converting to an ultrathin compound film, the step of forming the ultrathin metal reactant thin film and the step of converting to the ultrathin metal compound film. This is solved by forming the metal compound thin film having a desired film thickness on the substrate.
[0018]
In this way, after forming an ultrathin film of incomplete metal reactant, a reaction mechanism is adopted that sequentially converts it into a metal compound ultrathin film. A small number of high-quality metal compound thin films can be formed at high speed.
[0019]
Also, in the process of forming an ultra-thin metal reactant thin film, an alternating voltage is applied so that each target becomes a cathode and an anode, and at the same time, one of the targets is a cathode and one of the targets is an anode. Therefore, the non-conductive or low-conductivity metal compound attached to the target surface when each target is an anode is removed from the target surface when the target becomes a cathode. Accordingly, accumulation of the metal compound on each target surface can be prevented, and a stable anode portion can be secured, and the anode potential can be prevented from changing to form a high-quality thin film with good reproducibility.
[0020]
In this case, it is preferable that the active species of the electrically neutral reactive gas include at least one of a radical, an excited radical, an excited atom, and an excited molecule. is there.
These radicals, radicals in an excited state, atoms in an excited state, and molecules in an excited state are charged with ions, electrons, etc. in the chemical reaction of the reactive film-forming process in which a metal compound is obtained from an incomplete reactant of the metal. It plays a more important role than particles. Moreover, it has the characteristic of not damaging a thin film like a charged particle.
Therefore, in the present invention, an active species of an electrically neutral reactive gas including at least one of a radical having the above characteristics, a radical in an excited state, an atom in an excited state, and a molecule in an excited state is provided. Since it uses, it becomes possible to perform the process of converting into a metal compound ultrathin film efficiently.
[0021]
Further, the active species of the electrically neutral reactive gas is introduced through a grid that introduces the reactive gas to generate reactive gas plasma and selectively passes the electrically neutral active species. It is preferable to configure so as to be introduced into the vacuum chamber.
[0022]
According to the invention according to claim 4, in the apparatus for forming a metal compound thin film on a substrate by sputtering, the object is electrically insulated from a ground potential and connected to an AC power source, and the AC power source provides a positive potential. A plurality of sputtering targets that can be alternately applied to the negative potential and a film forming process zone formed in a vacuum chamber for performing a step of forming a metal incomplete reactant ultra-thin film on the substrate; Inert gas and the total gas flow rate of the deposition process zone More than 3% Reactive gas with a flow rate of 20% or less , Through piping connected in the deposition process zone A gas introduction means for introducing into the film-forming process zone; and means for generating electrically neutral reactive gas active species, wherein the metal incomplete reactant thin film reacts with the active species of the reactive gas. A reaction process zone formed in a vacuum chamber for performing a step of converting into a metal compound ultrathin film, a substrate holder for transferring the substrate between the film formation process zone and the reaction process zone, and the film formation process This is solved by providing shielding means for spatially and pressure-separating the zone and the reaction process zone.
[0023]
Thus, since the film formation process zone and the reaction process zone are separated by the shielding means, the metal incomplete reactant thin film is formed in the film formation process zone, and the metal compound ultrathin film is formed in the reaction process zone. It is possible to perform conversion, and after forming an ultra-thin metal reactant thin film, it is possible to adopt a reaction mechanism that converts it into a metal compound ultra-thin film sequentially, forming a thin film with smaller stress, and optical absorption It is possible to form a high-quality metal compound thin film with a small amount at high speed.
In addition, since the film formation process zone and the reaction process zone are separated by the shielding means, the film formation process zone and the reaction process zone are not completely separated, but are separated in a substantially independent vacuum atmosphere. It can be formed as a space.
[0024]
As a result, each zone can have a vacuum atmosphere in which influences from other zones are individually suppressed, and optimum conditions can be set for each zone. For example, the discharge caused by sputtering and the discharge caused by the generation of reactive species of the reactive gas can be controlled separately and do not affect each other, so that stable discharge can be achieved and reliability is ensured without causing accidents. Can be increased. In addition, the reactive gas flow rate in the film forming process zone can be easily controlled, and abnormal discharge can be prevented. Further, since the shielding means is provided, it is possible to prevent the vapor deposition material from being mixed into other film forming process zones, particularly when different types of targets are used for each film forming process zone.
At this time, it is preferable that the film formation process zone and the reaction process zone are formed in the same vacuum chamber.
[0025]
The active species generating means includes a reactive gas introducing means for introducing a reactive gas, the reactive gas plasma generating means connected to a power source for applying a voltage, and the reactive gas plasma generating means. It is preferable to provide a grid that selectively passes electrically neutral active species in the generated reactive gas plasma.
As described above, since the reactive gas plasma generating means and the grid for selectively passing the electrically neutral active species in the reactive gas plasma generated by the reactive gas plasma generating means are provided. In the reaction to convert incomplete reactants of metals into metal compounds, radicals that play a decisive role than charged particles such as ions and electrons, radicals in an excited state, atoms in an excited state, A certain molecule can be used, and it becomes possible to perform a process of efficiently converting to a metal compound ultrathin film.
[0026]
The substrate holder is preferably electrically insulated from the vacuum chamber.
As a result, abnormal discharge in the substrate can be prevented.
[0027]
The film formation process zone and the reaction process zone are formed in the same vacuum chamber, and a substrate load chamber for mounting the substrate on the substrate holder and detachment of the substrate from the substrate holder are performed. A substrate unloading chamber, the substrate loading chamber and the vacuum chamber, and the substrate unloading chamber and the vacuum chamber are connected to each other via a pressure-separable blocking means, and the substrate loading chamber and the vacuum chamber The vacuum chamber and the substrate unload chamber each have their own exhaust means, and substrate holder transport means for transporting the substrate holder between the substrate load chamber, the vacuum chamber and the substrate unload chamber is provided. It is preferable to be disposed.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a method for forming a metal compound thin film in which a metal compound thin film having a target film thickness is formed on a substrate by forming and depositing a plurality of metal compound ultra thin films by sputtering.
[0029]
The ultra-thin film as used in the present invention is a term used to prevent confusion with the final thin film because the ultra-thin film is deposited multiple times to form a final thin film. Is also quite thin. The average thickness of the ultrathin film is arbitrary, but is preferably about 0.1 to 15 Å.
The present invention can be carried out by various known sputtering methods such as dipolar sputtering, tripolar sputtering, quadrupolar sputtering, magnetron sputtering, ECR sputtering, and bias sputtering.
[0030]
In the present invention, a plurality of the same or different kinds of sputtering targets 29a, 29b, 49a, 49b electrically insulated from the vacuum chamber 11 at the ground potential are alternately arranged on the cathode and the anode. At the same time, an AC voltage of 1 KHz to 100 KHz is applied so that any one of the targets 29a, 29b, 49a, 49b is a cathode and any one of the targets 49a, 49b, 29a, 29b is an anode. A step of introducing an inert gas and a reactive gas to form a metal incomplete reactant ultra-thin film made of an incomplete metal reactant on the substrate in the film forming process zones 20 and 40 in the vacuum chamber 11; , Separated from the film forming process zones 20 and 40 in the vacuum chamber 11 in terms of space and pressure. In the process zone 60, the reactive species of electrically reactive gas that is electrically neutral is brought into contact with the ultra-thin metal reactant ultrathin film, and the ultra-thin metal reactant ultra-thin film reacts with the reactive gas active species. Forming a plurality of metal compound ultrathin films by sequentially converting the process of converting to an ultrathin metal compound film, the process of forming the ultrathin metal film of the incomplete metal reactant, and the process of converting to an ultrathin metal compound film. Then, a metal compound thin film is formed.
[0031]
In the present invention, the process of forming the incomplete metal reactant ultra-thin film and the process of converting to the metal compound ultra-thin film may be repeated sequentially, and only the method of repeating these processes by rotating the drum-type substrate holder. Rather,
A composite metal compound thin film can be formed by providing a plurality of film formation process zones 20 and 40 and using targets having different compositions as the targets 29a, 29b, 49a and 49b of the film formation process zones 20 and 40, respectively.
[0032]
The pressure in the film forming process zones 20 and 40 is 1.0 × 10 ^-1 It is preferable to set it to -1.3Pa.
The flow rate ratio of the reactive gas introduced into the film forming process zones 20 and 40 is slightly different depending on the type of the reactive gas to be introduced, but is about 20% or less of the total gas flow rate in the film forming process zones 20 and 40, preferably It should be about 8% or less. By setting this ratio, it is possible to prevent abnormal discharge from occurring on the target surfaces of the film forming process zones 20 and 40.
Further, the flow rate ratio of the reactive gas introduced into the film forming process zones 20 and 40 is slightly different depending on the type of the reactive gas to be introduced, but about 3% or more of the total gas flow rate in the film forming process zones 20 and 40, Preferably, it may be about 5% or more. By using this ratio, it is possible to form a high-quality metal compound thin film with little optical absorption at a high speed with a small stress.
[0033]
A process of forming a composite metal compound thin film on a substrate will be described with reference to FIG. 11 by taking as an example the case of forming a composite metal oxide thin film.
First, the substrate is placed in the film forming process zone 20 so as to face the first metal targets 29a and 29b. Then, while introducing oxygen gas as a reactive gas, the first metal targets 29a and 29b are sputtered to form a very thin first metal incomplete oxide ultrathin film (left in FIG. 11).
[0034]
Next, the substrate is placed in the film forming process zone 40 so as to face the second metal targets 49a and 49b. At this position, while introducing oxygen gas as a reactive gas, the second metal targets 49a and 49b are sputtered to form a very thin second metal incomplete oxide ultrathin film (center of FIG. 11). . At this time, the first metal incomplete oxide ultrathin film and the second metal incomplete oxide ultrathin film are uniformly formed on the substrate. That is, an ultrathin film made of an incomplete oxide of a composite metal is formed on the substrate.
[0035]
The ultrathin film formed on the substrate is irradiated with active species of oxygen gas as an electrically neutral reactive gas, and the ultrathin film is reacted with the active species of oxygen gas to oxidize the composite metal. It converts into a thing (FIG. 11 right). Specifically, the oxidation is performed in the reaction process zone 60 having a radical source.
The step of forming the ultra-thin film and the step of converting to a compound of a composite metal are sequentially repeated to form a compound metal compound thin film having a desired film thickness on the substrate. In this embodiment mode, the step of forming an ultrathin film and the step of converting to a compound of a composite metal may be sequentially repeated to form a composite metal compound thin film having a desired thickness on the substrate, or the substrate may be transported. The substrate may be fixed.
[0036]
In the step of converting to a metal compound ultrathin film, the active species of the electrically neutral reactive gas includes at least one of a radical, an excited radical, an excited atom, and an excited molecule. Use things.
This electrically neutral reactive gas active species introduces a reactive gas to generate a reactive gas plasma, selectively traps electrons and ions that are charged particles, and is electrically neutral. It is generated by passing through a grid 81 through which active species are selectively passed. Via this grid 81, active species of an electrically neutral reactive gas are introduced into the vacuum chamber 11.
[0037]
The present invention also relates to an apparatus for forming a metal compound thin film by sputtering.
The apparatus according to the present invention includes gas introduction means 25 and 45 for introducing a reactive gas and an inert gas, film formation process zones 20 and 40, a reaction process zone 60, film formation process zones 20 and 40, and a reaction process. A substrate holder 13 for transporting a substrate to and from the zone 60 and shielding means 12, 14, and 16 for spatially and pressure-separating the deposition process zones 20 and 40 and the reaction process zone 60 are provided.
[0038]
The film forming process zones 20 and 40 are formed in the vacuum chamber 11. The film formation process zones 20 and 40 are provided with a plurality of sputtering targets that are electrically insulated from the ground potential and connected to an AC power source and can be alternately applied to a positive potential and a negative potential by the AC power source. Has been. In this zone, a process of forming a metal incomplete reactant ultra-thin film on the substrate is performed.
The reaction process zone 60 is formed in the vacuum chamber 11 and includes an electrically neutral reactive gas active species generating means 61. In the zone 60, a process of reacting the metal incomplete reactant ultra-thin film with the active species of the reactive gas to convert it into a metal compound ultra-thin film is performed.
[0039]
At this time, in particular, the pressure in the film formation process zones 20 and 40 is set higher than that in the reaction process zone 60. Thereby, the reactive gas introduced into the reaction process zone 60 is prevented from flowing into the film formation process zones 20 and 40, and the flow rate of the reactive gas in the film formation process zones 20 and 40 is set to a predetermined flow rate. Can be maintained.
In this example, the film formation process zones 20 and 40 and the reaction process zone 60 are formed in the same vacuum chamber 11.
[0040]
The electrically neutral reactive gas active species generating means 61 is a device that generates at least one of a radical, an excited radical, an excited atom, and an excited molecule. .
This active species generating means 61 includes a reactive gas introducing means 77 for introducing a reactive gas, a reactive gas plasma generating means 63 connected to an AC power source 69 of 1 KHz to 100 KHz for applying a voltage, and a reaction A grid 81 for selectively passing electrically neutral active species in the reactive gas plasma generated by the reactive gas plasma generating means 63.
[0041]
The plasma generated by the discharge in the reactive gas plasma generation chamber 63 of the active species generator 61 includes plasma ions, electrons, radicals, excited radicals, atoms, molecules, and the like as constituent elements.
In the present invention, the grid 81 is configured to selectively or preferentially guide radicals, excited radicals, atoms, molecules, and the like, which are active species in the reactive gas plasma, to the reaction process zone 60. Electrons and ions that are charged particles are prevented from passing through the grid 81 and do not leak into the reaction process zone 60.
[0042]
Therefore, in the reaction process zone 60, the metal incomplete reactant ultrathin film is exposed to and reacts with the active species of the electrically neutral reactive gas without being exposed to the charged particles. The ultra-thin film is converted into a metal compound. Here, a radical is a radical, which is an atom or molecule having one or more unpaired electrons. The excited state refers to a state having higher energy than the stable ground state having the lowest energy.
As the grid 81, a multi-aperture grid 101 or a multi-slit grid 111 is used.
[0043]
As the reactive gas plasma generating chamber 63 of the active species generating means 61, a coiled electrode is disposed on the atmosphere-side peripheral surface of a cylindrical dielectric, and high frequency power of 100 kHz to 50 MHz is applied to the coiled electrode. An inductively coupled plasma generation source that generates plasma by applying the plasma can be used.
Also, use an inductively coupled plasma generation source in which a spiral coil electrode is disposed on the atmosphere side of a disk-shaped dielectric, and a plasma is generated by applying a high frequency power of 100 KHz to 50 MHz to the spiral coil electrode. You can also.
[0044]
Further, a capacitively coupled plasma generation source may be used in which a plate-like electrode is disposed inside the reactive gas plasma generation unit, and plasma is generated by applying high-frequency power of 100 KHz to 50 MHz to the plate-like electrode.
Generation of plasma in which inductively coupled plasma and capacitively coupled plasma are mixed by arranging coiled electrodes or spiral coil electrodes inside the reactive gas generator and applying high frequency power of 100 kHz to 50 MHz to these electrodes A source can also be used.
[0045]
In the reactive gas plasma generation chamber 63, helicon wave plasma can be generated. Further, the reactive gas plasma generation chamber 63 may be provided with an external coil 71 or an internal coil 73 that forms a magnetic field of 20 to 300 gauss. If comprised in these, it will become possible to raise the generation | occurrence | production efficiency of the active species of the said active species generation means 61. FIG.
[0046]
The substrate holder 13 is electrically insulated from the vacuum chamber 11.
As a result, abnormal discharge in the substrate can be prevented.
Further, members disposed in the film forming process zones 20 and 40, for example, the shielding means 12 and 14 and a target shield covering the target are provided with a cooling means such as water cooling. Thereby, the temperature rise of the substrate due to plasma can be prevented, and a high quality thin film can be formed.
[0047]
In the present invention, as shown in FIG. 9, the film formation process zones 20 and 40 and the reaction process zone 60 are formed in the same vacuum chamber 121, and the substrate load for mounting the substrate 141 to the substrate holder 143 is used. The chamber 123 and the substrate unload chamber 125 for removing the substrate from the substrate holder 143 are provided. The substrate loading chamber 123 and the vacuum chamber 121, and the substrate unloading chamber 125 and the vacuum chamber 121 are connected via blocking means 131 and 135 that can be separated in pressure.
[0048]
The substrate load chamber 123, the vacuum chamber 121, and the substrate unload chamber 125 each have their own exhaust means rotary pump (RP), and between the substrate load chamber 123, the vacuum chamber 121, and the substrate unload chamber 125, Substrate holder transport means for transporting the substrate holder 143 is provided.
In the substrate loading chamber 123 and the substrate unloading chamber 125, other pre-processing and post-processing can be performed as necessary.
[0049]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The members, arrangements, and the like described below are not intended to limit the present invention and can be variously modified within the scope of the gist of the present invention.
[0050]
1 and 2 are explanatory views showing a thin film forming method and apparatus according to the present invention. FIG. 1 is a top view in which a partial cross section is taken for easy understanding, and FIG. 2 is a line AB in FIG. FIG.
In this example, magnetron sputtering, which is an example of sputtering, is used. However, the present invention is not limited to this, and other known sputtering such as bipolar sputtering that does not use magnetron discharge can also be used.
[0051]
The metal compound thin film forming apparatus of this example includes a vacuum chamber 11, film formation process zones 20 and 40 formed by shielding plates 12 and 14 as shielding means in the vacuum chamber 11, and film formation process zones 20 and 40. Magnetron sputtering targets 29a, b, 49a, b as sputtering targets arranged inside, a reaction process zone 60 formed by a shielding plate 16 as shielding means in the vacuum chamber 11, and film forming process zones 20, 40 The substrate holder 13 disposed so that the substrate faces the reaction process zone 60 is a main component.
[0052]
The vacuum chamber 11 is made of a substantially rectangular parallelepiped hollow body typically used in sputtering. An exhaust pipe is connected to the bottom surface of the vacuum chamber 11, and a vacuum pump 15 capable of exhausting the inside of the vacuum chamber 11 is connected to the pipe as shown in FIG. The vacuum degree in the vacuum chamber 11 can be adjusted by the vacuum pump 15 and a controller (not shown).
[0053]
The film formation process zones 20 and 40 are provided in the vacuum chamber 11 as shown in FIG. The film forming process zone 20 is surrounded by the shielding plate 12 and the substrate holder 13, and the film forming process zone 40 is surrounded by the shielding plate 14 and the substrate holder 13.
In this example, two film forming process zones are provided. However, the present invention is not limited to this, and one film forming process zone or three or more film forming process zones may be provided. In this example, since two film formation process zones are provided, it is possible to sputter two kinds of substances different in each film formation process zone.
[0054]
The shielding plate 12 is made of a flat plate-like body made of stainless steel, and four shielding plates 12 are erected vertically on the wall surface of the vacuum chamber 11 so as to surround the film forming process zone 20. A water-cooling pipe (not shown) is attached to the shielding plate 12, and the shielding plate 12 is configured to be cooled.
The configuration of the shielding plate 14 is the same as that of the shielding plate 12 except that it surrounds the film forming process zone 40.
[0055]
In each of the film forming process zones 20 and 40, mass flow controllers 25 and 45 as gas introducing means are arranged via piping. The mass flow controllers 25 and 45 are connected to sputtering gas cylinders 27 and 47 for storing argon gas as an inert gas, and a reactive gas cylinder 79 for storing oxygen gas, nitrogen gas, fluorine gas and the like as reactive gases. . This reactive gas is controlled by the mass flow controllers 25 and 45 from the reactive gas cylinder 79 and can be introduced into the film forming process zones 20 and 40 through piping.
[0056]
Magnetron sputtering electrodes 21 a and 21 b are arranged in the film forming process zone 20. The magnetron sputter electrodes 21a and 21b are fixed to the vacuum chamber 11 at the ground potential via an insulating member (not shown). Therefore, the sputtering electrode 21a and the target 29a and the sputtering electrode 21b and the target 29b are electrically separated from each other. The magnetron sputter electrodes 21a and 21b are connected to an AC power source 23 via a transformer 24 so that an alternating electric field can be applied. Two targets 29a and 29b made of a thin film material metal are fixed to the surface of the magnetron sputter electrodes 21a and 21b on the substrate holder 13 side.
In the film forming process zone 40, targets 49a and 49b are arranged in the same manner as the targets 29a and 29b. The targets 29a, 29b, 49a, 49b are formed as a substantially disk-shaped body made of a vapor deposition material.
[0057]
Between the targets 29a, 29b, 49a, 49b and the substrate holder 13, a target shield (not shown) that is movable so as to block or open between the targets 29a, 29b, 49a, 49b and the substrate holder 13 is disposed. Has been. This target shield cuts off between the targets 29a, 29b, 49a, 49b and the substrate holder 13 at the start of sputtering until the sputtering is stabilized, and after the sputtering is stabilized, the targets 29a, 29b, 49a, 49b and the substrate holder 13 By opening the gap between them, it becomes possible to deposit on the substrate after the sputtering is stabilized.
Cooling means such as water cooling is disposed on the peripheral members of the film forming process zones 20 and 40 such as the target shield in order to prevent adverse effects due to heat generation such as temperature rise of the substrate.
[0058]
The reaction process zone 60 is provided in the vacuum chamber 11 as shown in FIG. reaction The process zone 60 is surrounded by the shielding plate 16 and the substrate holder 13. The configuration of the shielding plate 16 is the same as that of the shielding plate 12 except that it surrounds the reaction process zone 60.
An opening is formed in the wall surface of the vacuum chamber 11 in the reaction process zone 60, and an active species generator 61 as a reactive gas plasma generating means is connected to the opening.
[0059]
The active species generator 61 is also called a radical source, and includes a reactive gas plasma generation chamber 63 made of a quartz tube that generates a reactive gas plasma, and a coiled electrode 65 wound around the reactive gas plasma generation chamber 63. And a matching box 67, a high-frequency power source 69 connected to the coiled electrode 65 via the matching box 67, a mass flow controller 77, and a reactive gas cylinder 79 connected via the mass flow controller 77.
[0060]
A grid 81 is disposed between the reactive gas plasma generation chamber 63 and the vacuum chamber 11.
The grid 81 has a function of selectively passing only electrically neutral active species particles to the reaction process zone 60 while preventing charged particles from passing therethrough. This function is generated by neutralizing the surface of the grid 81 by charge exchange between ions and electrons in the plasma.
[0061]
As the grid 81, a multi-aperture grid or a multi-slit grid can be used.
FIG. 6 is a plan view showing the multi-aperture grid 101. The multi-aperture grid 101 is made of a flat plate made of a metal or an insulator, and has an infinite number of holes 103 having a diameter of about 0.1 to 3.0 mm.
[0062]
FIG. 7 is a plan view showing a multi-slit grid. The multi-slit grid 111 is made of a flat plate made of metal or an insulator, and is provided with an infinite number of slits having a width of about 0.1 to 1.0 mm. The grids 101 and 111 are provided with cooling pipes 105 and 115, respectively, and are configured to be cooled by water cooling.
[0063]
A reactive gas such as oxygen gas is supplied from the reactive gas cylinder 79 to the reactive gas plasma generation chamber 63 via the mass flow controller 77, and the high frequency power from the high frequency power source 69 is supplied to the coiled electrode via the matching box 67. When applied to 65, the reactive gas plasma is generated in the reactive gas plasma chamber 63.
[0064]
As shown in FIGS. 1 and 2, the external magnet 71 is disposed outside the reactive gas plasma generation chamber 63, and the internal magnet 73 is disposed outside the grid 81 in the reaction process zone 60. ing. The external magnet 71 and the internal magnet 73 have a function of generating a high-density plasma by forming a magnetic field of 20 to 300 gauss in the plasma generating unit and increasing the active species generation efficiency.
In this example, both the external magnet 71 and the internal magnet 73 are provided, but either the external magnet 71 or the internal magnet 73 may be provided.
[0065]
In this example, as the reactive gas plasma part, as shown in FIGS. 1 and 2, an inductively coupled plasma source having electrodes provided outside or inside the reactive gas plasma generation chamber is used. Inductively coupled plasma source (below (1)), capacitively coupled plasma source (below (2)), inductively coupled / capacitively coupled plasma source (with the coil electrode disposed in the reactive gas plasma generation chamber ( The following (3)) can also be used.
[0066]
That is,
(1) Plasma source shown in FIG. 3: A spiral (mosquito coil incense-like) coil electrode 91 is disposed on the atmosphere side of a reactive gas plasma generation chamber 63 made of a dielectric material such as a disc-shaped quartz glass, and this spiral shape. An inductively coupled plasma generating source that generates plasma by applying high frequency power of 100 KHz to 50 MHz to the coil electrode 91. FIG. 3B is a schematic explanatory view of a plane of the spiral coil electrode 91.
(2) Plasma source shown in FIG. 4: A flat electrode 93 is disposed inside the reactive gas plasma generation chamber 63, and plasma is generated by applying high frequency power of 100 KHz to 50 MHz to the flat electrode 93. Capacitively coupled plasma generation source.
(3) Plasma source shown in FIG. 5: A coiled electrode 95 or a spiral coil electrode is arranged inside the reactive gas generation chamber 63, and high frequency power of 100 KHz to 50 MHz is applied to these electrodes to generate inductively coupled plasma. A plasma generation source that generates plasma in which a capacitively coupled plasma is mixed.
Etc. can be used.
Further, by adjusting the coil shape and the like, a helicon wave plasma source can be obtained, and the generation efficiency of active species in the plasma can be increased.
[0067]
Hereinafter, the procedure for forming a multilayer antireflection film using the apparatus of this example will be described by taking as an example the case of forming a multilayer antireflection film in which silicon oxide and titanium oxide are laminated.
A substrate is set on the substrate holder 13. As targets 29a and 29b, silicon targets whose oxides have a low refractive index are fixed to the magnetron sputter electrodes 21a and 21b. As targets 49a and 49b, titanium targets whose oxide has a high refractive index are fixed to the magnetron sputter electrodes 41a and 41b. The inside of the vacuum chamber 11 is depressurized to a predetermined pressure.
[0068]
Thereafter, the pressure in the film forming process zone 20 is set to 1.0 × 10 6. ^-1 Adjust to ~ 1.3 Pa.
The motor 17 is operated to start the rotation of the substrate holder 13.
Argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are introduced into the film forming process zone 20 from the sputtering gas cylinder 27 and the reactive gas cylinder 79 by adjusting the flow rate with the mass flow controller 25 to form a film forming process. The sputtering atmosphere in the zone 20 is adjusted.
The flow rate of each gas introduced into the film forming process zone 20 at this time is about 300 sccm for argon gas and 15 to 24 sccm for oxygen gas.
[0069]
Then, an AC voltage having a frequency of 1 to 100 KHz is applied from the AC power source 23 to the sputtering electrodes 21a and 21b via the transformer 24 so that an alternating electric field is applied to the targets 29a and 29b.
Thereby, at a certain point in time, the target 29a becomes the cathode (negative pole), and at that time, the target 29b always becomes the anode (positive pole). When the direction of the alternating current changes at the next time point, the target 29b becomes the cathode (minus pole) and the target 29a becomes the anode (plus pole). In this way, the pair of targets 29a and 29b alternately become an anode and a cathode, so that plasma is formed and the target on the cathode is sputtered.
[0070]
At this time, non-conductive or low-conductivity silicon incomplete oxide, silicon oxide, etc. may adhere on the anode, but when this anode is converted into a cathode by an alternating electric field, these silicon incomplete oxidation Objects are sputtered, and the target surface becomes the original clean state.
By repeating this, a stable anode potential state is always obtained, a change in plasma potential (usually substantially equal to the anode potential) is prevented, and a silicon incomplete oxide ultrathin film is stably formed.
In this way, power is supplied from the sputtering AC power source 23, and silicon is sputtered to form SiO on the substrate. _x Deposition of an incomplete metal oxide thin film such as (x <2).
[0071]
Simultaneously with sputtering in the film forming process zone 20, oxygen gas as a reactive gas is introduced into the reaction process zone 60 from a reactive gas cylinder 79. High frequency power of 100 KHz to 50 MHz is applied to the coiled electrode 65, and plasma is generated by the active species generator 61. The pressure in the reaction process zone 60 is 0.7 × 10 ^-1 Maintain at ~ 1.0 Pa.
The plasma in the reactive gas plasma generation chamber 63 includes oxygen gas ions and electrons that are charged particles, radicals and excited radicals that are active species of electrically neutral reactive gases, atoms and molecules. Exists. Among them, the active species of the latter electrically neutral reactive gas are selectively or preferentially guided to the reaction process zone 60 by the grid 81.
[0072]
When the substrate holder 13 rotates and the substrate is in the film formation process zone 20, the metal incomplete oxide ultrathin film SiO _x When the substrate on which (x <2) is formed enters the reaction process zone 60, the ultra-thin film is completely oxidized by the active species of oxygen gas and becomes SiO 2 ₂ Is converted to
Thus, by rotating the substrate holder 13 on which the substrate is mounted, the metal incomplete oxide ultrathin film SiO in the film formation process zone 20 is obtained. _x (X <2) formation and SiO in the reaction process zone 60 ₂ Is repeatedly converted into SiO 2 having a desired film thickness on the substrate. ₂ Is formed.
The target 21 is made of SiO. ₂ May be used. Unlike the conventional RF and DC reactive sputtering method using a compound target, in the present invention, the target 21 is made of SiO 2. ₂ Even in the case where oxygen is used, since oxygen deficiency is compensated in the reaction process zone 60, stable SiO ₂ It is possible to form a film.
Thereafter, the sputtering AC power supply 23 is turned off.
[0073]
The pressure in the deposition process zone 240 is set to 1.0 × 10 ^-1 Adjust to ~ 1.3 Pa.
While adjusting the flow rate with the mass flow controller 45, argon gas as an inert gas is introduced from the sputtering gas cylinder 47 and oxygen gas as a reactive gas is introduced from the reactive gas cylinder 79 into the film forming process zone 40.
The flow rate of each gas introduced into the film forming process zone 20 at this time is about 300 sccm for argon gas and 15 to 24 sccm for oxygen gas.
An AC voltage having a frequency of 1 to 100 KHz is applied from the sputtering AC power supply 43 so that an alternating electric field is applied to the targets 49a and 49b. Sputtering titanium to form TiO on the substrate _x Deposition of an ultra-thin metal oxide thin film such as (x <2) is started.
[0074]
At the same time, oxygen gas as a reactive gas is introduced into the reaction process zone 60 from the reactive gas cylinder 79, and the active species generator 61 is operated to generate the active species of oxygen gas.
Then, when the substrate holder 13 rotates, the metal incomplete oxide ultrathin film TiO is formed on the substrate in the film formation process zone 40. _x (X <2) is formed, and in the reaction process zone 60, the ultrathin film is completely oxidized by the active species of oxygen gas to produce TiO 2. ₂ Is converted to
[0075]
Thus, by rotating the substrate holder 13 on which the substrate is mounted, the metal incomplete oxide ultrathin film TiO in the film formation process zone 40 is obtained. _x (X <2) formation and TiO in reaction process zone 60 ₂ Are repeatedly converted into TiO having a desired film thickness on the substrate. ₂ Is formed.
This SiO ₂ Forming TiO, and TiO ₂ And repeating the process of forming SiO 2 on the substrate. ₂ Thin film and TiO ₂ A multilayer antireflection film in which a thin film is laminated is formed.
[0076]
In this example, silicon and titanium are used as the targets 29a, b, 49a, and 49b. However, the present invention is not limited to these, and aluminum (Al), titanium (Ti), zirconium (Zr), tin (Sn) is used. ), Chromium (Cr), tantalum (Ta), silicon (Si), tellurium (Te), nickel-chromium (Ni—Cr), indium-tin (In—Sn), and other metal targets can be used. Also, compounds of these metals, such as Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , SiO ₂ , Nb ₂ O ₅ Etc. can also be used.
[0077]
When these targets are used, the exposure of reactive species of reactive gases in the reaction process zone 60 causes Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , SiO ₂ , Nb ₂ O ₅ Optical film or insulating film such as ITO, conductive film such as ITO, Fe ₂ O ₃ Or a super hard film such as TiN, CrN, or TiC.
TiO ₂ , ZrO ₂ , SiO ₂ Such an insulating metal compound has an extremely low sputtering rate and poor productivity as compared with metals (Ti, Zr, Si). Therefore, the dual magnetron sputtering method of the present invention is particularly effective.
[0078]
It should be noted that by using targets of different metals or metal compounds for the targets 29a, 29b and targets 49a, 49b, a multilayer antireflection film in which different metal compounds are laminated, for example, SiO ₂ And ZrO ₂ Multi-layer antireflection film with SiO ₂ And Ta ₂ O ₅ Multi-layer antireflection film with SiO ₂ And Nb ₂ O ₅ It is also possible to form a multilayer antireflection film or the like.
[0079]
In this example, as shown in FIG. 11, the reactive gas is introduced from the same reactive gas cylinder 79 into the film forming process zones 20 and 40 and the reaction process zone 60. The gas deposition process zones 20 and 40 and the reaction process zone 60 may be connected to different gas cylinders and different gases having the same element may be introduced.
[0080]
The targets 29a and 29b may be the same metal target or different metal targets. When the same metal target is used, a metal incomplete oxide ultrathin film made of a single metal is formed, and when a different metal target is used, an metal incomplete oxide ultrathin film made of an alloy is formed. The same applies to the targets 49a and 49b.
[0081]
The reactive gas introduced into the film forming process zones 20 and 40 and the reaction process zone 60 includes ozone, dinitrogen monoxide (N ₂ O) oxidizing gas, nitriding gas such as nitrogen, carbonizing gas such as methane, fluorine, carbon tetrafluoride (CF ₄ Fluorine gas etc. can be used.
In addition, when introducing nitrogen gas into the film-forming process zones 20 and 40, the gas flow rates introduced into the film-forming process zones 20 and 40 are preferably set to 300 sccm of argon gas as inert gas and 9 to 60 sccm of nitrogen gas.
[0082]
In the following, according to this example, SiO ₂ And Ta ₂ O ₅ Or Nb ₂ O ₅ Operation conditions when a multilayer antireflection film is formed are shown.
(1) Sputtering condition (Si) input power: 7.0 kW
Substrate temperature: room temperature
Deposition process zone pressure: 1.3 Pa
Applied AC voltage frequency 40KHz
Substrate holder rotation speed: 100 rpm
Ultrathin film thickness: 2-6 angstroms
(2) Sputtering conditions (Ta / Nb)
Input power: 5.0 kW
Substrate temperature: room temperature
Deposition process zone pressure: 1.3 Pa
Applied AC voltage frequency 40KHz
Substrate holder rotation speed: 100 rpm
Ultrathin film thickness: 1-4 angstrom
(3) Driving conditions of active species generator (O ₂ )
Apparatus: Inductively coupled plasma generation source shown in FIGS.
Input power: 2.0kW
Pressure: 6.5 × 10 ^-1 Pa
[0083]
A graph showing the relationship between the attenuation coefficient of the thin film formed by the metal compound thin film forming method of this example and the film forming speed is shown in FIG.
Sample A (O in FIG. ₂ Is a graph of a thin film formed by the method of forming a metal compound thin film of the present example using the metal compound thin film forming apparatus shown in FIG. 1, specifically, the operating conditions (1) to (3) ).
In addition, sample B (O ₂ No) is proportional, and specifically, for the formed metal compound thin film without introducing a reactive gas into the film forming process zones 20 and 40 of the metal compound thin film forming apparatus shown in FIG. It is a graph. The other configurations of the thin film forming apparatus and the forming method of sample B are the same as the configuration of this example related to sample A, and the operating conditions are also based on the operating conditions (1) to (3).
[0084]
From FIG. 8, according to the formation method of the metal compound thin film of this example according to sample A, the attenuation coefficient is the same as that of the comparative metal compound thin film formation method according to sample B even at the same film formation rate. It was found that a thin film having a low thickness was formed. That is, according to the method for forming a metal compound thin film of this example, optical absorption is small even at the same film formation rate, as compared with a comparative method in which no reactive gas is introduced into the film formation process zone. It has been found that a thin film can be obtained.
Furthermore, as shown in FIG. 10, according to the method for forming a metal compound thin film of this example, it has been found that a film formation rate substantially the same as that of the conventional twin magnetron sputtering method can be obtained.
[0085]
FIG. 9 is a plan view showing another embodiment of the present invention. The overall configuration of the apparatus is a film forming chamber 121 as a vacuum chamber, a substrate loading chamber 123 before and after that, and a substrate unloading chamber 125. Each chamber has a separate exhaust system, RP indicates a rotary pump, and TMP indicates a turbomolecular pump. The chambers are connected through gate valves 131 and 133. The substrate loading chamber 123 can be opened to the atmosphere by a gate valve 135 or an opening / closing door, and the substrate unloading chamber 125 can be opened / closed to the atmosphere by a gate valve 137 or an opening / closing door. That is, each chamber is isolated in pressure and has its own exhaust system, and the substrate holder 143 can be transported through the gate valves 131 and 133.
[0086]
A substrate holder 143 on which the substrate 141 is mounted is carried into the substrate load chamber 123 via the gate valve 135, and the substrate load chamber 123 is evacuated by a rotary pump, and is subjected to pretreatment such as heating. In other words, the substrate loading chamber 123 is a chamber that performs functions of removing / exhausting the substrate holder, pretreatment as necessary. After this process is completed, the substrate holder 143 is transferred to the film formation chamber 121. A thin film is formed on the substrate 141 in the film formation chamber 121. Note that, in order to avoid complication, only the substrate holder 143 in the film formation chamber 121 is indicated by a one-dot chain line in the drawing, and the illustration of the substrate 141 is omitted.
[0087]
The substrate holder 143 that has completed the film forming process is transferred to the substrate unloading chamber 125, subjected to post-processing as necessary, and then taken out through the gate valve 137. In other words, the substrate unload chamber 125 is a chamber in which the substrate holder is attached / detached / evacuated / after-treatment as necessary. The film forming process in the film forming chamber 121 is the same as that of the embodiment shown in FIGS. 1 and 2 except that the substrate holder has a horizontal plate shape.
[0088]
【The invention's effect】
As described above, according to the present invention, a metal compound thin film having stable characteristics can be formed at high speed with a simple configuration and operation.
It is known that a strong stress is generated in a metal thin film. However, in the method for forming a metal compound thin film according to the present invention, first, an ultra-thin metal reactant thin film is formed, and then the metal compound ultra-thin film is formed. Since a reaction mechanism for sequentially converting them is employed, it is possible to form a thin film having a smaller stress as compared with the conventional method of converting a metal ultrathin film into a metal compound ultrathin film. Furthermore, a high-quality metal compound thin film with little optical absorption can be formed at high speed.
[0089]
Also, by repeatedly forming the metal incomplete reactant ultra-thin film and converting it to the metal compound ultra-thin film, the metal compound ultra-thin film is deposited multiple times, so that the desired thickness of the thin film can be reduced to a low substrate It can be formed at high speed with temperature.
As a method for forming ultrathin metal incomplete reactants Dual magnetron sputtering method As a result, it is possible to secure a stable anode portion, prevent a change in anode potential, and form a high-quality thin film with good reproducibility.
[0090]
When converting an incomplete metal reactant ultrathin film to a metal compound ultrathin film, by using active species such as radicals, radicals in an excited state, atoms or molecules, the thin film is compared with the case of using charged particles. Can be prevented from being damaged, and the substrate temperature can be prevented from rising, and a thin film having good characteristics can be obtained efficiently.
The film formation process zone and the reaction process zone are separated by the shielding means, and the discharge for sputtering and the discharge for generating active species of the reactive gas can be controlled individually, enabling stable discharge and stable. Thin film formation can be performed.
The flow rate ratio of the reactive gas introduced into the film formation process zone is the total gas flow rate in the film formation process zone. About 3% or more By setting it to about 20% or less, it is possible to prevent abnormal discharge from occurring on the target surface in the film forming process zone.
[Brief description of the drawings]
FIG. 1 is an explanatory top view showing an embodiment of an apparatus used in the present invention.
2 is a cross-sectional view taken along line ABC in FIG. 1, showing an embodiment of the apparatus used in the present invention.
FIG. 3 is an explanatory diagram showing a configuration example of a plasma source.
FIG. 4 is an explanatory diagram showing a configuration example of a plasma source.
FIG. 5 is an explanatory diagram showing a configuration example of a plasma source.
FIG. 6 is a plan view showing a multi-aperture grid.
FIG. 7 is a plan view showing a multi-slit grid.
FIG. 8 is a graph showing the relationship between the attenuation coefficient of a thin film formed by the metal compound thin film forming method of this example and the film formation rate.
FIG. 9 is an explanatory plan view showing an embodiment of an apparatus used in the present invention.
FIG. 10 is an explanatory diagram showing a relationship between a reactive gas ratio and a film formation rate.
FIG. 11 is an explanatory view when a compound metal compound thin film is formed on a substrate.
[Explanation of symbols]
11 Vacuum chamber
12, 14, 16 Shield plate
13 Substrate holder
15 Vacuum pump
17 Motor
20, 40 Deposition process zone
21a, 21b, 41a, 41b Sputter electrode
23, 43 AC power supply for sputtering
24 transformer
25, 45 Mass flow controller
27, 47 Sputter gas cylinder
29a, 29b, 49a, 49b Target
60 reaction process zone
61 Active species generator
63 Reactive gas plasma generation chamber
65 electrodes
67 Matching box
69 High frequency power supply
71 External coil
73 Internal coil
77 Mass Flow Controller
79 Reactive gas cylinders
81 grid
91 Spiral electrode
93 Plate electrode
95 Coiled electrode
101 Multi-Aperture Grid
103 holes
105 Cooling pipe
111 Multi slit grid
113 slit
115 Cooling pipe
121 Deposition chamber
123 Board loading chamber
125 Substrate unloading chamber
131, 133, 135, 137 Gate valve
141 Substrate
143 Substrate holder
151,161,171 Shield plate
153, 163 Deposition process zone
155a, 155b, 165a, 165b target
173 Reaction process zone
175 Active species generator

Claims (8)

An AC voltage is applied to a plurality of sputtering targets that are electrically isolated from the ground potential so that each target alternates between a cathode and an anode, and at the same time, either target becomes a cathode and any target becomes an anode. In the film forming process zone in the vacuum chamber, an inert gas and a reactive gas having a flow rate of 3% or more and 20% or less of the total gas flow rate of the film forming process zone are connected to the film forming process zone. A step of forming a metal incomplete reactant ultra-thin film made of an incomplete metal reactant on a substrate , introduced by a gas introduction means for introducing into the film formation process zone through the pipe formed;
In the reaction process zone that is spatially and pressure-separated from the film formation process zone in the vacuum chamber, an active species of an electrically neutral reactive gas is brought into contact with the metal incomplete reactant reactant ultrathin film, Reacting the metal incomplete reactant ultrathin film with active species of the reactive gas to convert it into a metal compound ultrathin film;
A step of sequentially repeating the step of forming the metal incomplete reactant ultrathin film and the step of converting to the metal compound ultrathin film,
A method of forming a metal compound thin film, comprising: forming and depositing a plurality of the metal compound ultra-thin films, and forming the metal compound thin film having a desired film thickness on a substrate.   The metal compound thin film according to claim 1, wherein the active species of the electrically neutral reactive gas includes at least one of a radical, an excited radical, an excited atom, and an excited molecule. Forming method.   The active species of the electrically neutral reactive gas is a vacuum chamber through a grid that introduces the reactive gas to generate reactive gas plasma and selectively passes the electrically neutral active species. The metal compound thin film forming method according to claim 1, wherein the metal compound thin film is introduced into the metal compound thin film. In an apparatus for forming a metal compound thin film on a substrate by sputtering,
A plurality of sputtering targets which are electrically insulated from the ground potential and connected to an AC power source and can be alternately applied to a positive potential and a negative potential by the AC power source are disposed, and the metal incomplete reaction occurs on the substrate. A film forming process zone formed in a vacuum chamber for performing a process of forming an ultra-thin film;
An inert gas and a reactive gas having a flow rate of 3% or more and 20% or less of the total gas flow rate of the film formation process zone are introduced into the film formation process zone through a pipe connected to the film formation process zone. and gas introducing means for introducing,
A vacuum chamber comprising means for generating an electrically neutral reactive gas active species and performing a step of reacting the metal incomplete reactant ultra-thin film with the active species of the reactive gas to convert it into a metal compound ultra-thin film A reaction process zone formed within,
A substrate holder for transporting the substrate between the deposition process zone and the reaction process zone;
An apparatus for forming a metal compound thin film, comprising: shielding means for spatially and pressure-separating the film formation process zone and the reaction process zone.   5. The apparatus for forming a metal compound thin film according to claim 4, wherein the film forming process zone and the reaction process zone are formed in the same vacuum chamber. The means for generating the active species is:
A reactive gas plasma generating means connected to a power source for applying a voltage, the reactive gas introducing means for introducing the reactive gas;
5. The metal compound thin film according to claim 4, further comprising a grid that selectively allows electrically neutral active species in the reactive gas plasma generated by the reactive gas plasma generating means to pass therethrough. apparatus.   5. The apparatus for forming a metal compound thin film according to claim 4, wherein the substrate holder is electrically insulated from the vacuum chamber. The film formation process zone and the reaction process zone are formed in the same vacuum chamber,
A substrate loading chamber for mounting the substrate to the substrate holder, and a substrate unloading chamber for removing the substrate from the substrate holder,
The substrate loading chamber and the vacuum chamber, and the substrate unloading chamber and the vacuum chamber are connected via a pressure-separable blocking means, respectively.
The substrate loading chamber, the vacuum chamber, and the substrate unloading chamber each have their own exhaust means,
5. The apparatus for forming a metal compound thin film according to claim 4, wherein substrate holder transfer means for transferring the substrate holder is disposed between the substrate load chamber, the vacuum chamber, and the substrate unload chamber. .

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