VACUUM TREATMENT APPARATUS AND VACUUM TREATMENT METHOD

A vacuum treatment apparatus including: a first wind-off roller paying out a first base material; a first wind roller winding the first base material; a main roller having an outer circumferential surface in contact with a non-film deposition surface, and winding and conveying the first base material, at least a part of the outer circumferential surface, which is uncovered with the first base material, being coated with an insulating material; a deposition source facing the outer circumferential surface of the main roller; a second wind-off roller paying out a second base material that is wound and conveyed by the main roller and covers a part of a film deposition surface of the first base material on the outer circumferential surface of the main roller; a second wind roller winding the second base material; and a power source applying a bias potential to the main roller.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority Patent Application JP 2022-130962 filed Aug. 19, 2022, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present invention relates to a vacuum treatment apparatus and a vacuum treatment method.

There is known a film deposition system using roll-to-roll processing that forms a film on an elongated film deposition target base material (band-like film) while winding the base material through a main roller in a pressure-reduced atmosphere. In such a film deposition system, a deposition source is disposed facing the film deposition target base material wound and conveyed by the main roller for depositing a film deposition material fed from the deposition source on the film deposition target base material (e.g., see Japanese Patent Application Laid-open No. 2009-019246 (hereinafter, referred to as Patent Literature 1)). Accordingly, the film is formed on the film deposition target base material wound and conveyed by the main roller.

SUMMARY

The above-mentioned film deposition system in some cases winds and conveys the film deposition target base material and a masking base material for covering a part of base material for the film deposition through the main roller and deposits the film deposition material on a predetermined portion of the film deposition target base material.

However, in those cases, an electrical short-circuit where electric charges with which the masking base material is charged due to electrostatic charging flow down to the main roller can occur when the masking base material is peeled off from the film deposition target base material. In a case of performing film deposition while applying a bias potential on the main roller, such a short-circuit can make the bias potential unstable during film deposition.

In view of the above-mentioned circumstances, it is desirable to provide a vacuum treatment apparatus and a vacuum treatment method that are capable of stably applying a bias potential to a main roller during film deposition.

According to an embodiment of the present invention, a vacuum treatment apparatus includes a first wind-off roller, a first wind roller, a main roller, a deposition source, a second wind-off roller, a second wind roller, and a power source.

The first wind-off roller pays out a first base material having a film deposition surface and a non-film deposition surface opposite to the film deposition surface.

The first wind roller winds the first base material.

The main roller is provided between the first wind-off roller and the first wind roller in a direction in which the first base material is conveyed, has an outer circumferential surface that is held in contact with the non-film deposition surface, and winds and conveys the first base material, at least a part of the outer circumferential surface, which is uncovered with the first base material, being coated with an insulating material.

The deposition source faces the outer circumferential surface of the main roller that is held in contact with the non-film deposition surface.

The second wind-off roller pays out a second base material that is wound and conveyed by the main roller and covers a part of the film deposition surface of the first base material on the outer circumferential surface of the main roller.

The second wind roller winds the second base material.

The power source applies a bias potential to the main roller.

In accordance with such a vacuum treatment apparatus, the bias potential can be stably applied to the main roller during film deposition.

In the vacuum treatment apparatus, the main roller may have both end portions coated with the insulating material.

In accordance with such a vacuum treatment apparatus, the bias potential can be stably applied to the main roller during film deposition.

In the vacuum treatment apparatus, the second base material may be wound and conveyed by the main roller while the second base material is held in contact with the insulating material on the outer circumferential surface of the main roller.

In accordance with such a vacuum treatment apparatus, the bias potential can be stably applied to the main roller during film deposition.

According to an embodiment of the present invention, a vacuum treatment method includes by use ofa first wind-off roller that pays out a first base material having a film deposition surface and a non-film deposition surface opposite to the film deposition surface,a first wind roller that winds the first base material,a main roller that is provided between the first wind-off roller and the first wind roller in a direction in which the first base material is conveyed, has an outer circumferential surface that is held in contact with the non-film deposition surface, and winds and conveys the first base material, at least a part of the outer circumferential surface, which is uncovered with the first base material, being coated with an insulating material,a deposition source that faces the outer circumferential surface of the main roller that is held in contact with the non-film deposition surface,a second wind-off roller that pays out a second base material that is wound and conveyed by the main roller and covers a part of the film deposition surface of the first base material on the outer circumferential surface of the main roller, anda second wind roller that winds the second base material,forming a film deposition material on the film deposition surface while applying a bias potential to the main roller.

In accordance with such a vacuum treatment method, the bias potential can be stably applied to the main roller during film deposition.

In the vacuum treatment method, both end portion of the main roller may be coated with the insulating material.

In accordance with such a vacuum treatment method, the bias potential can be stably applied to the main roller during film deposition.

In the vacuum treatment method, the second base material may be wound and conveyed by the main roller while the second base material is held in contact with the insulating material on the outer circumferential surface of the main roller.

In accordance with such a vacuum treatment method, the bias potential can be stably applied to the main roller during film deposition.

As described above, in accordance with the present invention, a vacuum treatment apparatus and a vacuum treatment method that are capable of stably applying a bias potential to a main roller during film deposition is provided.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. XYZ-axis coordinates are used in some figures of the drawings. Moreover, the same components or components having the same functions will be sometimes denoted by the same reference signs and duplicated descriptions of the components will be sometimes omitted as appropriate. In addition, numeric values described below are exemplary and not limitative.

FIG.1is a schematic diagram showing an example of a vacuum treatment apparatus according to the present embodiment. A vacuum treatment apparatus1illustrated inFIG.1is a vacuum treatment apparatus using roll-to-roll processing that forms a film on an elongated base material90under a condition of a pressure-reduced atmosphere below an atmospheric pressure. InFIG.1, a direction of a center axis40cof a main roller40is a Y-axis direction and a direction from a deposition source20to the main roller40is a Z-axis direction. A direction orthogonal to the Y-axis direction and the Z-axis direction is an X-axis direction.

The vacuum treatment apparatus1includes a vacuum chamber10, the deposition source20, the main roller40, a wind-off roller41(first wind-off roller), a wind roller42(first wind roller), a wind-off roller45(second wind-off roller), a wind roller46(second wind roller), a bias power source50, and a gas discharge mechanism70. A guide roller (not shown) for guiding the base material90(first base material) may be provided between the main roller40and the wind-off roller41or between the main roller40and the wind roller42. A guide roller (not shown) for guiding a base material95(second base material) may be provided between the main roller40and the wind-off roller45or between the main roller40and the wind roller46. The vacuum treatment apparatus1includes a rotational driving mechanism (not shown) for rotating each of the main roller40, the wind-off roller41, the wind roller42, the wind-off roller45, the wind roller46, and the guide roller. Moreover, the vacuum treatment apparatus1may include a gas feeding mechanism for feeding a gas into the vacuum chamber10.

In the vacuum treatment apparatus1, the base material90is a base material for film deposition and is conveyed to the main roller40from the wind-off roller41and to the wind roller42from the main roller40at a predetermined conveying velocity inside the vacuum chamber10. For example, the base material90is wound by the wind-off roller41and paid out to the main roller40from the wind-off roller41. The base material90paid out to the main roller40from the wind-off roller41is wound and conveyed by the main roller40and is wound by the wind roller42. A film deposition material fed from the deposition source20is deposited on the base material90wound and conveyed by the main roller40and a film is formed on the base material90.

The base material95is a masking base material for covering the base material90. The base material95is conveyed at a predetermined conveying velocity inside the vacuum chamber10to the main roller40from the wind-off roller45and to the wind roller46from the main roller40. For example, the base material95is wound by the wind-off roller45and is paid out to the main roller40from the wind-off roller45. The base material95paid out to the main roller40from the wind-off roller45is wound and conveyed by the main roller40while covering a part of the base material90wound and conveyed by the main roller40and is wound by the wind roller46.

The vacuum chamber10has a hermetically-sealed structure. The vacuum chamber10can be kept in a predetermined pressure-reduced atmosphere through the gas discharge mechanism70with the vacuum pump P1. The vacuum treatment apparatus1includes, for example, a film deposition chamber11and a treatment chamber12. The film deposition chamber11and the treatment chamber12are partitioned by a partition wall13. The vacuum chamber10houses the deposition source20, the main roller40, the wind-off roller41, the wind roller42, the wind-off roller45, and the wind roller46in the example inFIG.1.

The partition wall13has an opening14so that a part of the main roller40can enter the film deposition chamber11from the treatment chamber12without contact between the main roller40and the partition wall13. Moreover, the presence of the opening14in the partition wall13makes a clearance between the main roller40and the partition wall13. The base materials90and95wound and conveyed by the main roller40pass between the treatment chamber12and the film deposition chamber11through this clearance.

The deposition source20is provided in the film deposition chamber11. The deposition source20includes an evaporation source, for example. The deposition source20faces an outer circumferential surface403of the main roller40. The deposition source20includes a resistance heating evaporation source, an induction heating evaporation source, an electron-beam heating evaporation source, and other evaporation sources. A film deposition material, e.g., an alkaline metal or alkaline earth metal is evaporated toward the main roller40from the deposition source20. The film deposition material includes alkaline metals such as Li and Na and alkaline earth metals such as Mg and Ca, for example. A film formed on the base material90has a thickness of 20 μm or less. When a Li film is used as the film, this film is used for a negative electrode of a lithium battery, for example.

The film deposition chamber11is connected to the gas discharge mechanism70. The film deposition chamber11maintains a reduced-pressure state through the gas discharge mechanism70. The treatment chamber12is in communication with the film deposition chamber11through the opening14. The treatment chamber12is evacuated through the opening14when the film deposition chamber11is evacuated. In the example inFIG.1, the treatment chamber12is not connected to the gas discharge mechanism70. Accordingly, a pressure difference is generated where the pressure of the treatment chamber12is higher than the pressure of the film deposition chamber11when the film deposition chamber11is evacuated. This pressure difference inhibits a vapor flow21(film deposition material) from the deposition source20from entering the treatment chamber12through the opening14. It should be noted that the treatment chamber12is evacuated through the gas discharge mechanism depending on needs.

The main roller40is provided between the wind-off roller41and the wind roller42in a direction in which the base material90is conveyed (direction along the direction of the conveyed base material90). A part of the main roller40is arranged in the film deposition chamber11and the other part is arranged in the treatment chamber12. The main roller40faces the deposition source20. The main roller40has the outer circumferential surface403that is held in contact with a non-film deposition surface (back surface)90rof the base material90. In the example inFIG.1, the main roller40rotates counter-clockwise. In the present embodiment, the direction in which the main roller40rotates will be referred to as a direction of rotation R.

The main roller40contains a metal material such as stainless steel, iron, and aluminum and has a tubular shape. For example, a temperature control mechanism (not shown) may be provided inside the main roller40. A width of the main roller40in the direction of the center axis40cis set to be larger than a width of the base material90. The main roller40winds and conveys the base material90unwound by the wind-off roller41and pays out the base material90with the film formed thereon toward the wind roller42.

At least a part of the outer circumferential surface403of the main roller40is coated with an insulating material410in the form of a layer. The insulating material410is provided surrounding the main roller40along the outer circumferential surface403. For example, at least a part of the outer circumferential surface403, which is uncovered with the base material90, is coated with the insulating material410when the main roller40winds and conveys the base material90. The insulating material410has a thickness of, for example, 10 μm or more and 100 μm or less. If the insulating material410has a thickness smaller than 10 μm, it deteriorates insulation of the insulating material410, so it is unfavorable. If the insulating material410has a thickness larger than 100 μm, a step of the base material90in contact with the insulating material410on the main roller40is thicker, so it is unfavorable.

Examples of the material of the insulating material410include an oriented polypropylene (OPP) resin, a polyethylene terephthalate (PET) resin, a polyphenylene sulfide (PPS) resin, and a polyimide (PI) resin.

The wind-off roller41is provided in the treatment chamber12. The base material90is wound around the wind-off roller41in advance. The wind-off roller41rotates around its center axis in the arrow direction at a predetermined rotation velocity. The wind-off roller41pays out the base material90toward the main roller40.

The wind roller42is provided in the treatment chamber12. The wind roller42rotates around its center axis in the arrow direction at a predetermined rotation velocity. The wind roller42winds the base material90wound and conveyed by the main roller40and has the film deposition material deposited thereon.

The wind-off roller45is provided in the treatment chamber12. The base material95is wound around the wind-off roller45in advance. the wind-off roller45rotates around its center axis in the arrow direction at a predetermined rotation velocity. The wind-off roller45pays out the base material95toward the main roller40.

The wind roller46is provided in the treatment chamber12. The wind roller46rotates around its center axis in the arrow direction at a predetermined rotation velocity. The wind roller46winds the base material95after the base material95covering the part of the base material90on the main roller40is peeled off from the base material90.

The base material90includes a film deposition surface90dand a non-film deposition surface90ropposite to the film deposition surface90d. The film deposition surface90dfaces the deposition source20. The vapor flow21fed from the deposition source20is deposited on the film deposition surface90dand a film is formed on the film deposition surface90dof the base material90on the main roller40. The non-film deposition surface90ris held in contact with the outer circumferential surface403of the main roller40.

The base material90is a sheet-like elongated film (with a thickness of 50 μm or less). The base material90is flexible. For example, the base material90is a band-like film constituted by an oriented polypropylene (OPP) resin, a polyethylene terephthalate (PET) resin, a polyphenylene sulfide (PPS) resin, and/or a polyimide (PI) resin. The base material90may be a band-like metal foil constituted by Cu, Al, Ni, and/or SUS steel, for example.

The base material95includes a covering surface95rthat covers a part of the film deposition surface90dand a non-covering surface95sopposite to the covering surface95r. The base material95covers the part of the film deposition surface90dof the base material90on the outer circumferential surface403of the main roller40. The non-covering surface95sof the base material95faces the deposition source20. The base material95covering the part of the film deposition surface90dof the base material90causes a film to be formed in a predetermined portion of the film deposition surface90dof the base material90on the main roller40.

The base material95is a sheet-like elongated film (with a thickness of 50 μm or less). The base material95is flexible. For example, the base material95is a band-like film constituted by an oriented polypropylene (OPP) resin, a polyethylene terephthalate (PET) resin, a polyphenylene sulfide (PPS) resin, and/or a polyimide (PI) resin.

The bias power source50is provided outside the vacuum chamber10. The bias power source50applies a bias potential (e.g., a positive potential) to the main roller40. Applying the bias potential to the main roller40causes an electrostatic force to act between the base material90and the main roller or between the base material95and the main roller. Accordingly, an electrostatic adhesion force acts between the main roller40and the base materials90and95when the main roller40winds and conveys the base materials90and95, and it suppresses deviation and wrinkling of the base material90and the base material95on the main roller40. It should be noted that the vacuum chamber10, the wind-off roller41, the wind roller42, the wind-off roller45, and the wind roller46are set at a ground potential.

An operation of depositing the film deposition material from the deposition source20on the film deposition surface90dof the base material90by the use of the vacuum treatment apparatus1will be described.FIG.2(a)toFIG.2(c)are cross-sectional views schematically showing an example of the vacuum treatment method according to the present embodiment.

FIG.2(a)schematically shows cross-sections of the respective base materials, the film, the insulating material, and the main roller taken along the long dashed short dashed line C1 shown inFIG.1.

As shown inFIG.2(a), both end portions (end portions401and402) of the main roller40are coated with the insulating material410. The insulating material410is, for example, divided into two parts, includes an insulating material411and an insulating material412. For example, the one end portion401of the main roller40is coated with the insulating material411and the other end portion402of the main roller40is coated with the insulating material412. At the position of the long dashed short dashed line C1, the base material90is wound and conveyed by the main roller40, one end portion901of the base material90is located on the insulating material411, and the other end portion902of the base material90is located on the insulating material412.

Moreover, at the position of the long dashed short dashed line C1, the base material95for masking is wound and conveyed by the main roller40, held in contact with the insulating material410on the outer circumferential surface403of the main roller40. The base material95is constituted by two elongated base materials, for example, and includes a base material951and a base material952, for example. The base material951covers the insulating material411and the one end portion901of the base material90on the side of the insulating material411. The base material952covers the insulating material412and the other end portion902of the base material90on the side of the insulating material412.

It should be noted that in a case of conveying the base material95divided into the two parts as such, the wind-off roller45in the vacuum treatment apparatus1may be constituted by an integrated wind-off roller that simultaneously pays out the base material951and the base material952or may be constituted by a pair of wind-off rollers that independently pays out each of the base material951and the base material952. When the wind-off roller45is constituted by a pair of wind-off rollers, the pair of wind-off rollers is arranged in parallel in the direction of the center axis40cof the main roller40. Similarly, the wind roller46may be constituted by an integrated wind roller that simultaneously winds the base material951and the base material952or may be constituted by a pair of wind rollers that independently winds each of the base material951and the base material952. When the wind roller46is constituted by a pair of wind rollers, the pair of wind rollers is arranged in parallel in the direction of the center axis40cof the main roller40.

As shown inFIG.2(a), at the position of the long dashed short dashed line C1, the vapor flow21is deposited on the base material90uncovered with the base material95and the base material95(base materials951and952). Accordingly, a film91including the film deposition material from the deposition source20is formed on the base material90. Moreover, a residual film910including the film deposition material is formed on the base material95(base materials951and952). It should be noted that during film deposition, the film deposition material is formed on the film deposition surface90dof the base material90while applying the bias potential to the main roller40.

FIG.2(b)schematically shows cross-sections of the respective base materials, the film, the insulating material, the residual film, and the main roller taken along the long dashed short dashed line C2 shown inFIG.1.

At the position of the long dashed short dashed line C2, the base material95(base materials951and952) and the residual film910are moved away from the insulating material410and the base material90. After that, the base material95and the residual film910are wound by the wind roller46.

On the other hand, the base material90with the film91formed thereon remains on a portion of the main roller40, which is uncovered with the base material95. After that, the base material90and the film91are moved away from the main roller40and are wound by the wind roller42. This state is shown inFIG.2(c). For example,FIG.2(c)schematically shows cross-sections of the main roller and the insulating material taken along the long dashed short dashed line C3 shown inFIG.1.

As shown inFIG.2(c), the base material90and the film91are moved away from the main roller40and a part of the outer circumferential surface403of the main roller40is coated with the insulating material410(insulating materials411and412). After that, the state inFIG.2(a)is provided again, and then the operations shown in the order ofFIG.2(b)andFIG.2(c)are repeated.

Actions of a vacuum treatment apparatus according to a comparative example will be described before describing actions of the vacuum treatment apparatus1.FIG.3(a)toFIG.3(c)are diagrams describing the actions of the vacuum treatment apparatus according to the comparative example.FIG.3(a)shows the comparative example corresponding to the position of the long dashed short dashed line C1 inFIG.1andFIG.3(b)shows the comparative example corresponding to the position of the long dashed short dashed line C2 inFIG.1.FIG.3(c)shows an equivalent circuit showing the state inFIG.3(b).FIG.3(a)toFIG.3(c)show actions on the side of the end portion401of the both end portions of the main roller40. A phenomenon shown inFIG.3(a)toFIG.3(c)can also occur on the side of the end portion402of the main roller40.

In the comparative example, the insulating material410(insulating materials411and412) is not provided on the main roller40. With such a configuration, the following phenomenon can occur.

For example, when the main roller40winds and conveys the base materials90and95, the base materials90and95can be charged with static electricity due to a difference in charging series between the base material90and the base material95and friction between the base material90and the base material95.

For example,FIG.3(a)shows a state in which the end portion901of the base material90is charged to have a positive potential and the base material951is charged to have a negative potential as an example. It should be noted that the respective films are both at the ground potential because the film91formed on the base material90is wound by the wind roller42and the residual film910formed on the base material951is wound by the wind roller46. Moreover, a positive potential is applied on the main roller40from the bias power source50.

Keeping such a state, when the base material951is moved away from the main roller40as shown inFIG.3(b), the degree of vacuum between the base material951and the end portion901of the base material90locally increases because the base material951is degassed, for example. In addition, an electric field is formed between the base material951and the end portion901of the base material90due to the static electricity charging the base material951and the static electricity charging the base material90. Accordingly, discharge plasma80can be generated between the base material951and the end portion901of the base material90. The discharge plasma80can be generated also when the end portion901of the base material90is charged to have a negative potential and the base material951is charged to have a positive potential.

When such discharge plasma80is generated near the portion where the outer circumferential surface403of the main roller40is exposed, electric charges in the discharge plasma80are attracted to the outer circumferential surface403of the main roller40. As a result, an electrical path80pis formed between the discharge plasma80and the outer circumferential surface403of the main roller40(FIG.3(c)). That is, an electrical short-circuit occurs between the discharge plasma80and the main roller40.

When such an electrical short-circuit occurs, the bias potential applied on the main roller40becomes unstable and the electrostatic adhesion force between the main roller40and the base materials90and95becomes unstable. Accordingly, the base materials90and95may be deviated on the outer circumferential surface403of the main roller40or the base materials90and95may be wrinkled during film deposition.

Next, actions of the vacuum treatment apparatus according to the present embodiment will be described.FIGS.4(a) and4(b)are diagrams describing the actions of the vacuum treatment apparatus according to the present embodiment.FIG.4(a)shows an example corresponding to the position of the long dashed short dashed line C2 inFIG.1.FIG.4(b)shows an equivalent circuit showing the state inFIG.4(a).FIGS.4(a) and4(b)show actions on the side of the end portion401of the both end portions of the main roller40. A phenomenon shown inFIGS.4(a) and4(b)also occurs on the side of the end portion402of the main roller40.

As shown inFIG.4(a), in the present embodiment, the main roller40is coated with the insulating material410(insulating materials411and412). Accordingly, as shown inFIG.4(a), the electric charges in the discharge plasma80are shielded by the insulating material411even if the discharge plasma80is formed between the base material951and the end portion901of the base material90. Accordingly, the electrical path80pis not formed (FIG.4(b)) and electric charges in the discharge plasma80are inhibited from reaching the outer circumferential surface403of the main roller40.

Therefore, the bias potential applied on the main roller40is stable and the electrostatic adhesion force between the main roller40and the base materials90and95is stable. Accordingly, the base materials90and95are inhibited from being deviated on the outer circumferential surface403of the main roller40and the base materials90and95are inhibited from being wrinkled during film deposition.

Hereinabove, the embodiments of the present invention have been described, though the present invention is not limited to those embodiments and various modifications can be made as a matter of course. For example, the present embodiment also encompasses a configuration in which the entire region of the outer circumferential surface403of the main roller40is coated with the insulating material and similar actions and effects are provided also with this configuration. The respective embodiments are not limited to the aspects in which they are independently carried out and can be combined as long as it is technically possible.