JP4617164B2 - Deposition equipment - Google Patents

Description

  The present invention relates to a film forming apparatus for forming thin films on various substrates.

Carbon and silicon thin films or compound thin films containing nitrogen, hydrogen, etc. are used for various protective films and liquid crystal display panels because of their high hardness and excellent engineering and electrical characteristics. Have a wide range of uses.
Examples of a method for depositing these thin films on the substrate surface include a sputtering method under a vacuum atmosphere, a CVD method, and a laser ablation method. Among these, the sputtering method and the plasma CVD method are widely used industrially as a technique for forming a film on a flat substrate or a film-like substrate in a simple and large area.

As an example of a method of depositing a thin film on the substrate surface using the sputtering method, a voltage is applied to a cathode electrode having a solid evaporation source (target) to perform discharge, and the substrate is continuously parallel to the target surface. There is a method of forming a film by transporting it. This method is generally performed by an apparatus called an in-line sputtering apparatus, and is used as a means for mass-producing DLC ultrathin films (film thickness of about 10 nm).
In the case of performing the sputtering method, carbon is deposited not only on the substrate but also on all the structures such as a deposition plate around the cathode electrode in the vacuum chamber, and the carbon thin film is deposited by repeating this. It will be.

  If the deposited thin film has an insulating property, electric charges are accumulated on the surface of the thin film, causing abnormal discharge. Further, as the deposited amount of the insulating thin film increases, Concentrated accumulation of positive charges occurs, and arc discharge is likely to occur. Due to this arc discharge, the glow discharge on the cathode electrode side transitions to arc discharge, causing a problem that the discharge stops. When the discharge is stopped, in the state where the stable anode potential disappears in the vicinity of the cathode electrode due to the deposition of the insulating thin film, there is a problem that the discharge does not resume even if the voltage is reapplied to the cathode.

  In addition, when the abnormal discharge occurs or after the occurrence, a part of the carbon coating or scattered carbon particles peeled off from the internal structure is reattached to the target surface, and this is a protruding structure composed of carbon particles as a nucleus. There is a problem that an object (nodule) is formed and abnormal discharge is caused. In addition, the peeled carbon coating may become a dust source, and particles composed of carbon particles may adhere to the substrate, or the adhered particles may serve as a pinhole source for coatings that are laminated in subsequent substrate processing steps. As a result, there has been a problem that the yield of the product is lowered.

  Furthermore, since the structure such as the inner wall of the vacuum chamber and the deposition preventing plate is covered with an insulating film, the surface of these structures does not serve as an anode electrode because the surface of the structure does not become a ground potential with respect to the cathode electrode. As a result, there is a problem that the stability of the discharge is lacking and the film forming speed, film thickness / film quality distribution becomes non-uniform.

  In order to solve the above problems, it is conceivable to frequently remove the insulating film on the inner wall of the vacuum chamber and the surface of the internal structure at the earth potential, or periodically clean the target surface (see Patent Document 1). However, there is a problem that the frequency of performing maintenance by stopping the apparatus increases, and productivity is poor.

Further, Patent Document 2 discloses that the amount of film deposition on the structure around the cathode electrode is suppressed. Specifically, the anode electrode provided in the vicinity of the cathode electrode is configured to have a multilayer structure with a gap, and gas is ejected from the gap toward the target, but the structure is complicated and cleaning is performed. There was a problem that time work also took time.
Further, as another method for suppressing the number of abnormal discharges, the tip shape of the ground shield provided in the vicinity of the outer periphery of the target of the cathode is processed into an R shape, and a deposition plate called chimney sprayed with Al is used as the cathode and the substrate. An apparatus that is provided in a grounded state is disclosed in Patent Document 3. When this apparatus is used in a production line, although the deposited earth shield and chimney are periodically blast washed, it is difficult to maintain the tip shape of the earth shield in the initial state for a long period of time, There was a problem that the maintenance cost was high.

  For the purpose of suppressing the growth of nodules on the target, Patent Document 4 discloses that alternating current is applied alternately to two sputter cathodes, and when one of the cathodes is at the cathode potential, the other is always at the anode potential. An AC sputtering method is disclosed. However, the AC sputtering method reduces the film forming speed to about 1/2 with respect to the same applied power as compared with the DC sputtering method, so that the power source capacity has to be increased by about twice. There was a problem that it took.

In addition to the above sputtering method, the plasma CVD method exemplified above is typically amorphous silicon (a-Si), silicon nitride (SiN _x ), silicon oxide (SiO _x ), mainly for display panel applications. , Silicon oxynitride (SiO _x N _y ), and n-doped amorphous silicon (n + a-Si).
When these thin films are formed on the substrate, the film forming gas is turned into plasma using high-frequency power, but the film peeled off from the structure around the electrode part and the vacuum chamber wall as in the above sputtering method. There was a problem that a part induced abnormal discharge and became a source of dust generation.

JP-A-10-110256 JP-A-8-232064 JP 2001-73115 A JP 2004-143535 A

  It is an object of the present invention to provide a film forming apparatus that suppresses the abnormal discharge, film peeling, or target nodule growth caused by them, or reduces dust generation sources. Another object of the present invention is to provide a film forming apparatus capable of suppressing the film deposition rate on the structure near the cathode electrode.

As a result of intensive studies, the present inventors have found a means for solving the problems as follows. That is, the film formation apparatus of the present invention, as described in claim 1, the substrate positioned at the opposite side of the cathode electrode having a negative potential, a film forming apparatus for forming a discharge phenomenon, the Provided with a grounded shield on the outer peripheral side of the cathode electrode, and at least one or more pillars configured to rotate freely as an anode electrode having a ground potential or a positive potential on the outer peripheral side of the cathode electrode and on the substrate side A body is pivotally supported along the outer peripheral direction of the cathode electrode, and anode electrode blades are erected on the outer peripheral surface of the anode electrode .
According to a second aspect of the present invention, there is provided a film forming apparatus according to the first aspect of the present invention, wherein the cathode electrode is provided with a target, and an outer edge of the upper surface of the cathode electrode. A deposition plate is provided so as to cover a portion, a gas introduction pipe for introducing a deposition gas is provided between the deposition plate and the anode electrode, and a film is formed on the substrate by a sputtering phenomenon. Features.
According to a third aspect of the present invention, there is provided the film forming apparatus according to the first aspect, wherein the film forming apparatus is configured to introduce a reactive gas and form a film on the substrate by a plasma CVD method. It is characterized by that.

  According to the present invention, the deposition rate of the insulating film on the anode on the outer periphery of the cathode electrode provided for plasma stabilization can be reduced, so that the film can be formed for a long time without replacing the anode electrode, and the anode electrode can be replaced. The frequency can also be reduced. In addition, since the frequency of occurrence of abnormal discharge is reduced, a thin film product having a stable film thickness and quality can be supplied.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a film forming apparatus according to an embodiment of the present invention.
A magnetron sputtering cathode electrode 2 is provided in a vacuum chamber 1 of the illustrated film forming apparatus. The cathode electrode 2 is composed of a backing plate 6 attached to one surface of the vacuum chamber 1 via an insulator 5 and a target 3. At least the target 3 is mechanically fixed to the upper surface of the backing plate 6. Alternatively, it is fixed by bonding. A grounded shield 8 is provided on the outer periphery of the cathode electrode 2 and the insulator 5 to prevent members other than the target 3 from being sputtered, and a magnetic circuit 7 is provided outside the vacuum chamber of the backing plate 6. A sputter cathode is configured, and a power supply 36 for applying a voltage is connected to the backing plate 6. A shield plate 9 is provided on the outer periphery of the shield 8 so that particles sputtered from the target do not adhere from the target 3 to the inner wall of the vacuum chamber 1 or the surface of other components in the chamber (not shown). ing.
A substrate transport mechanism (not shown) is disposed on the side facing the cathode electrode 2 so that the substrate 4 can be transported in parallel to the target 3. The target 3 has a rectangular shape and is arranged so that its longitudinal direction is perpendicular to the transport direction of the substrate 4.
The cathode electrode 2 includes a backing plate 6 attached to the bottom of the vacuum chamber 1 via an insulator 5 and a magnet 7 provided below the backing plate 6. The upper surface of the backing plate 6 is configured such that at least the target 3 can be mechanically fixed or fixed by bonding. On the outer peripheral side of the cathode electrode 2, a grounded shield 8 for preventing members other than the target 3 from being sputtered is disposed so as to cover the outer edge of the upper surface of the backing plate 6. Further, on the outer peripheral side of the shield 8, an adhesion preventing plate 9 configured to cover the outer edge of the upper surface of the cathode electrode 2 is provided so that particles are not scattered from the target 3 to the inner wall of the vacuum chamber 1. It has been.
Further, a vacuum pump 11 is connected to the outside of the vacuum layer 1 through an on-off valve 10, and gas cylinders 16 and 17 are connected through introduction pipes 12 and 13 and mass flow controllers 14 and 15.

  In the present embodiment, the rotatable anode electrodes 18 and 19 are axially supported along the long side of the outer periphery of the cathode electrode 2 above the shield 8. The anode electrodes 18 and 19 are grounded or a voltage is applied so as to be a positive potential. The anode electrodes 18 and 19 are provided with a plurality of anode electrode blades 18b and 19b erected on the rotation shafts 18a and 19a radially at a predetermined angle around the rotation shafts 18a and 19a, and are rotated by a driving mechanism (not shown). It is configured to be able to. The anode electrode blades 18b and 19b can be structured to be removable from the rotary shafts 18a and 19a, respectively.

In the above configuration, a film forming gas is introduced into the vacuum chamber 1 from the introduction pipes 12 and 13 and a negative voltage is applied to the backing plate 6, whereby a negative voltage is also applied to the surface of the target 3, and discharge is performed. Is generated, and sputtering is performed on the target 3.
At this time, the sputtered particles flying from the target 3 preferentially adhere to the anode electrode blades 18b and 19b. Then, by rotating the anode electrodes 18 and 19 at a predetermined interval, it is possible to play a role of preventing the shield 8 from being deposited within a range where film deposition does not become a problem.

  In the above-described embodiment, the anode electrodes 18 and 19 have been described as having a plurality of blades 18b and 19b. However, the anode electrodes 18 and 19 have a structure in which the amount of deposited film on the anode electrodes 18 and 19 is not a problem. The shape is not particularly limited as long as the cathode electrode 2 side of 18 and 19 can be retracted. Accordingly, a cylindrical shape, a polygonal column shape, or the like can be used. Further, the anode electrodes 18 and 19 may be constantly rotated, or may be repeatedly rotated and stopped at a predetermined interval.

Further, in the embodiment shown in FIG. 1, the example in which one cathode electrode 2 is arranged in the vacuum chamber 1 is shown. However, as shown in FIG. When the cathode electrodes 2 and 2 are arranged, a plurality of anode electrodes 18, 19 and 20 may be arranged along the outer peripheral direction of the cathode electrodes 2 and 2. In the illustrated example, a single anode electrode 19 is provided between the adjacent cathode electrodes 2 and 2, and the structure is simplified so that the cathode electrodes 2 and 2 are shared.
In the embodiment shown in FIGS. 1 and 2, the anode electrodes 18, 19, and 20 are arranged along one direction on the outer periphery of the cathode electrode 2. For example, if the cathode electrode 2 is rectangular, four anode electrodes may be arranged along each side. Further, the method of axially supporting the anode electrode in one direction is not particularly limited, and the anode electrode may be divided into a plurality of axes in one direction.

  Further, in the embodiment shown in FIG. 1 described above, the case where the adhesion preventing plate 9 is provided has been described, but for the purpose of adhesion to the inner wall of the vacuum layer 1 and the surface of the components in the vacuum layer 1 as with the adhesion preventing plate 9. In addition, it is possible to pivotally arrange a columnar body configured to be rotatable at a position where there is no hindrance to film formation or conveyance on the substrate 4, and a plurality of rotations are possible depending on the structure of the apparatus. It is also possible to arrange the columnar bodies configured as described above by pivotally supporting them.

Next, with reference to FIG. 3, a film forming apparatus for performing plasma CVD processing according to another embodiment of the present invention will be described.
In the illustrated film forming apparatus, a cathode electrode 23 is provided on the ceiling of the vacuum chamber 21 via an insulating member 22, and a shield 24 is erected on the outer periphery of the cathode electrode 23. The cathode electrode 23 is connected to a high frequency power source 27 via a power supply member 25 and a matching unit 26.
A substrate holder 29 with a built-in heater 28 is provided on the side facing the cathode electrode 23, and the substrate 30 is fixed on the substrate holder 29.
In addition, a gas introduction pipe 33 for introducing a source gas is connected to the vacuum chamber 21, and the gas after the reaction of the source gas introduced from the gas introduction pipe 33 reacts with the vacuum chamber 21. The vacuum pump 35 connected via the on-off valve 34 is configured to be exhausted to the outside.

  In the present embodiment, anode electrodes 31 and 32 that are pivotally supported in parallel with the surface of the cathode electrode 23 and configured to be rotatable are arranged near the lower portions of both ends of the shield 24. 32 can apply a ground potential or a positive potential. The anode electrodes 31 and 32 are configured by a plurality of anode electrode blades 31b and 32b being erected around the rotation shafts 31a and 32a in the same manner as the anode electrodes 18 and 19 described in FIG. It can be rotated by a mechanism.

In the above configuration, the raw material gas is introduced from the gas introduction pipe 33, high frequency power is supplied from the cathode electrode 23, the substrate 30 is heated from behind by the heater 28, and the reaction between the electrodes 23, 31, and 32 is caused by the reaction during discharge. A thin film is formed on the substrate 30.
At this time, the anode electrodes 31 and 32 function as a substitute for the deposition preventing plate 9 described with reference to FIGS. 1 and 2, and the amount of film deposition on the shield 24 that is particularly problematic can be reduced.

It should be noted that the anode electrodes 31 and 32 in the present embodiment can obtain the same effect even when they are formed in a cylindrical shape, a polygonal column shape, or the like, as described in the previous embodiment. In addition, the anode electrode blades 31a and 32a may be constantly rotated, or may be repeatedly rotated and stopped at a predetermined interval.
In the apparatus of FIG. 3, it is needless to say that the source gas is introduced into the electrode, the electrode surface facing the substrate is perforated, and the source gas is blown out toward the substrate.

In the above-described embodiment, the structure in which film formation is performed while moving the substrate has been described. However, the present invention can also be applied to a structure in which film formation is performed stationary on the opposite side of the cathode electrode.
As a power source that can be used in the above-described embodiment, a direct current or an alternating current power source represented by a high frequency power source can be used.

Next, a specific example of the film forming apparatus described in FIG. 1 will be described.
In this embodiment, the anode electrodes 18 and 19 are configured by standing up to six anode electrode blades 18b and 19b at 60 ° intervals radially in the circumferential direction of the rotary shafts 18a and 19a. The target 3 was made of carbon and fixed to the backing plate 6 by metal bonding.
Then, Ar gas is supplied from the gas introduction pipe 13 and H ₂ gas is supplied from the gas introduction pipe 12 so that the H ₂ addition amount becomes 10%, and the pressure in the vacuum chamber 1 is maintained at 0.2 Pa. The target 3 was discharged with DC power having a power density of 5 W / cm ² while exhausting the gas with the vacuum pump 11. The H ₂ flow rate was calculated based on the following equation.
H ₂ addition amount = 100 × (H ₂ flow rate) / (H ₂ flow rate + Ar flow rate)

The discharge is started in a state where the anode electrode blades 18b and 19b are close to the shield 8, and the anode electrode blades 18b and 19b are rotated by 60 ° every time 20 hours thereafter with the discharge being continued. The time-dependent change in the number of occurrences of abnormal discharge over 120 hours was measured so that 18b and 19b were close to the shield 8. The result is shown in FIG. In the figure, the horizontal axis represents the discharge time, and the vertical axis represents the cumulative number of abnormal discharges.
In FIG. 4, as a comparative example for comparison with the present example, a film forming apparatus having a configuration in which the anode electrodes 18 and 19 are removed from the film forming apparatus of the example is used. The results of measuring the time-dependent change in the number of abnormal discharges are also shown.
From FIG. 4, in the comparative example, the cumulative number of abnormal discharges was about 200, whereas in the example, the cumulative number of abnormal discharges was as small as 50 or more. In the film forming apparatus of the comparative example, arc discharge occurred, the power supply was shut off, and the discharge stopped. However, the film forming apparatus of this example did not have such a situation.
Thus, in the film forming apparatus of the example, the anode electrodes 18 and 19 are rotated by 60 ° at a rate of once every 20 hours, and the surfaces of the anode electrode blades 18b and 19b on which the carbon film is not formed are By sequentially moving to the position of the shortest distance from the cathode electrode 2, the amount of film deposition on the shield 8 and the amount of film deposition on the anode electrode blades 18b and 19b can be suppressed to a level at which abnormal discharge is unlikely to be induced. all right.

Next, the state of the surface of the target 3 after the continuous discharge is shown in FIG.
As shown in FIG. 5A, nodules c were generated only slightly on the surface of the target 3 used in the film forming apparatus of the example. On the other hand, a large amount of nodules c ′ was observed on the surface of the target 3 used in the film forming apparatus of the comparative example. When the area was calculated, the total area of the nodules c of the example was 21 mm ² , whereas the total area of the nodules c ′ of the comparative example was 116 mm ² .

In this example, carbon was used as the target 3, but other elements such as Si and B, carbon compounds containing these, In, Sn, Zn, oxides containing these as main components, or these An alloy oxide or the like can be used.
Further, although H ₂ is used as a gas to be introduced at the time of film formation, He, Ne, Xe, N ₂ or hydrocarbon gases can also be used.

  The present invention can be used for an apparatus for forming a film by applying a voltage, such as a sputtering apparatus (RF sputtering apparatus, AC sputtering apparatus, ECR sputtering apparatus) or a plasma CVD apparatus.

Explanatory drawing of the film-forming apparatus of one embodiment of this invention Explanatory drawing of the example of a change of the film-forming apparatus of FIG. Explanatory drawing of the film-forming apparatus of other embodiment of this invention In the film-forming apparatus of an Example, the plot which shows a time-dependent change of the abnormal discharge generation number at the time of carrying out a continuous discharge (Example, comparative example) Explanatory drawing which shows the state of the nodule of the target surface in the film-forming apparatus of an Example ((a) Example (b) Comparative example)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Cathode electrode 3 Target 4 Board | substrate 5 Insulator 6 Backing plate 7 Magnet 8 Shield 9 Deposition plate 10 Gate valve 11 Vacuum pump 12 Introducing pipe 13 Introducing pipe 14 Mass flow controller 15 Mass flow controller 16 Gas cylinder 17 Gas cylinder 18 Anode electrode 19 Anode electrode 20 Anode electrode 21 Vacuum chamber 22 Insulating member 23 Cathode electrode 24 Shield 25 Power supply member 26 Matching device 27 High frequency power supply 28 Heater 29 Substrate holder 30 Substrate 31 Anode electrode 32 Anode electrode 33 Gas introduction pipe 34 Open / close valve 35 Vacuum pump 36 Power source

Claims (3)

A film forming apparatus for forming a film by a discharge phenomenon on a substrate positioned on the opposite side of a cathode electrode having a negative potential, wherein a grounded shield is provided on the outer peripheral side of the cathode electrode, and the outer periphery of the cathode electrode is provided. And at least one columnar body that is configured to be rotatable as an anode electrode having a ground potential or a positive potential on the substrate side and on the substrate side. A film forming apparatus , wherein anode electrode blades are erected on the outer peripheral surface of the anode electrode . The cathode electrode is configured so as to be provided with a target, and a deposition plate is provided so as to cover an outer edge portion of the upper surface of the cathode electrode, and a film forming gas is provided between the deposition plate and the anode electrode. The film forming apparatus according to claim 1, wherein a gas introduction tube for introducing a gas is provided, and the film is formed on the substrate by a sputtering phenomenon.   The film forming apparatus according to claim 1, wherein the film forming apparatus is configured to introduce a reactive gas and form a film on the substrate by a plasma CVD method.

Images