JP2007308763A - Mask for plasma cvd, and method of cleaning mask for plasma cvd - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask for plasma CVD (chemical vapor deposition) where, in a state of maintaining the advantages of a metallic mask, the service life of the mask can be elongated even if a plasma CVD system is used for the cleaning of the mask. <P>SOLUTION: The mask 11 for plasma CVD is provided with: a metallic mask body 12 whose profile is rectangularly formed; and a ceramic cover 13 arranged on the periphery of the metallic mask body 12. The cover 13 is made of aluminum. The mask 11 for plasma CVD is cleaned using a plasma CVD system where a cleaning gas is fed from the side direction of the mask 11 for plasma CVD arranged inside a chamber into the chamber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma CVD mask and a method for cleaning a plasma CVD mask.

  2. Description of the Related Art In recent years, an organic electroluminescence element (hereinafter referred to as an organic EL element as appropriate) that has made remarkable developments is formed by laminating a first electrode, an organic EL layer, and a second electrode on a substrate, and is sensitive to moisture. A means of isolating (sealing) the layer from the outside air is required. As a means for isolating the organic EL layer from the outside air, it has been proposed to cover the organic EL element with a sealing film in order to make the organic EL element thinner and smaller in place of the sealing can and the sealing cap. Since the plasma CVD method can form a film at a lower temperature than the thermal CVD method, the sealing film of the organic EL element is plasma-treated so as to suppress an adverse effect on the organic EL layer at the time of forming the sealing film. It has been proposed to form a film by a CVD method (see, for example, Patent Document 1).

  The sealing of the organic EL element with the sealing film does not form a sealing film over the entire surface of the first electrode, the organic EL layer, and the second electrode on the substrate, but a part thereof, for example, connection for wiring Since it is necessary to form a film so that the portion is exposed, the film is formed only at a necessary position using a mask.

In such a film formation method using a mask, a film component adhering to the mask is removed when the film is formed by plasma CVD, that is, the mask is washed and the mask is reused. The mask is cleaned using the plasma CVD apparatus used for forming the sealing film. Then, the mask is placed in the chamber of the plasma CVD apparatus, and a cleaning gas is supplied to the plasma CVD to remove the film component attached to the mask.
JP 2006-59999 A

However, if the cleaning gas is used to remove the film component adhering to the metal mask, the mask is damaged by the cleaning gas and the life of the mask is shortened.
Patent Document 1 describes that the mask may be made of ceramic instead of metal. Thus, if the mask is made of ceramic, the mask is prevented from being damaged by the cleaning gas, and the life of the mask is not shortened. However, when the entire mask is made of ceramic, it is difficult to form a mask having a fine pattern. Further, if the entire ceramic mask is made thin like a metal mask (for example, 1 mm or less), handling becomes difficult.

  The present invention has been made in view of the above-described conventional problems. The first object of the present invention is to maintain the advantage of a metal mask while maintaining the lifetime even if a plasma CVD apparatus is used for cleaning the mask. The object is to provide a plasma CVD mask that can be extended. Another object of the present invention is to provide a plasma CVD mask cleaning method capable of extending the life of the mask.

  In order to achieve the first object, the invention according to claim 1 is a metal mask body having an outer shape formed in a polygon, and a ceramic cover disposed on at least one side of the metal mask body. And with. The plasma CVD mask of the present invention is used, for example, when a sealing film for an organic EL element is formed by a plasma CVD method. And when removing the film | membrane component adhering to the mask for plasma CVD, it cleans using a plasma CVD apparatus. The cleaning gas is supplied into the chamber from the side of the plasma CVD mask disposed in the chamber. When the mask does not include a ceramic cover disposed on one side of the metal mask main body as in the conventional case, the portion near the cleaning gas supply port is likely to deteriorate due to the influence of the cleaning gas. However, in this invention, by disposing the portion where the ceramic cover is placed in one side of the metal mask body near the cleaning gas supply port, deterioration of the metal mask body is suppressed, The life of the mask is extended.

  The invention according to claim 2 is the invention according to claim 1, wherein the ceramic is alumina. The inside of the chamber of the plasma CVD apparatus is cleaned by supplying a cleaning gas. Alumina is used as a material for the inner surface of the chamber and is suitable for cleaning. Therefore, in this invention, since the cover is made of alumina, the cover can be cleaned smoothly.

  In order to achieve the second object, the invention according to claim 3 is a method for cleaning a mask for plasma CVD, wherein when a thin film is formed by plasma CVD, at least a part of the periphery of the metal mask is made of ceramic. The film is formed in a state where the cover is placed. When the metal mask is cleaned, the metal mask is cleaned with a ceramic cover disposed on at least a portion of the metal mask close to the cleaning gas outlet.

  In this invention, the metal mask is cleaned using a plasma CVD apparatus. During film formation, film formation is performed in a state where a ceramic cover is disposed on at least a part of the periphery of the metal mask, so that no film component adheres to the metal mask in that part. When cleaning the metal mask, the cleaning is performed in a state in which the ceramic cover is disposed on at least the portion of the metal mask close to the cleaning gas blowing port. Deterioration is suppressed and the life of the metal mask is extended.

  The invention described in claim 4 is the invention described in claim 3, wherein the thin film formed by the plasma CVD is a sealing film of an organic electroluminescence element.

  According to the present invention, the life of the mask can be extended even if a plasma CVD apparatus is used for cleaning the mask while maintaining the advantages of the metal mask.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the plasma CVD mask 11 includes a metal mask body 12 and a ceramic cover 13. The metal mask main body 12 is formed with a rectangular outer shape, and has a predetermined pattern of openings 12a. The plasma CVD mask 11 is used for forming a large number of organic EL elements (multi-face), and the opening 12a corresponds to a portion where an organic EL element sealing film (not shown) is to be formed.

  The metal mask body 12 is made of a material such as invar, kovar, stainless steel (for example, SUS430), and has a thickness of about 0.5 mm. If the thickness of the edge portion of the opening 12a is large, the film thickness of the sealing film formed in the vicinity of the edge portion becomes thin, and the uniformity of the film thickness decreases. On the other hand, if the metal mask main body 12 is made too thin, the metal mask main body 12 is bent, and the sealing film cannot be accurately formed in a predetermined pattern. Therefore, the metal mask main body 12 is formed so that the periphery of the opening 12a is thinner than other portions.

  The cover 13 is formed in a rectangular frame shape corresponding to the periphery of the metal mask main body 12, and has an outer shape that is substantially the same as the outer shape of the metal mask main body 12. The cover 13 is made of alumina ceramic and has a thickness of about 10 mm. In the drawing, for the sake of convenience, the thicknesses of the metal mask main body 12 and the cover 13 are drawn substantially the same. The cover 13 is separate from the metal mask body 12 and is disposed on the periphery of the metal mask body 12.

  Next, a method of using the plasma CVD mask 11 configured as described above will be described. The plasma CVD mask 11 is used in a sealing film forming process when a large number of organic EL elements are manufactured (multiple processes). The sealing film is formed using a plasma CVD apparatus. For example, a parallel plate RF plasma induced CVD apparatus is used as the plasma CVD apparatus.

  As shown in FIG. 3, the plasma CVD apparatus 20 has a substrate holder 22 disposed in the lower part of a chamber 21, and a discharge electrode 24 having a shower head 23 disposed thereon. The substrate holder 22 contains a heater (not shown) for heating the substrate 30. The discharge electrode 24 is connected to a high frequency power source RF. A gas for film formation is supplied to the shower head 23 through a gas flow path (not shown). A gas discharge unit 25 for discharging the gas in the chamber 21 to the outside is connected to the chamber 21. The gas discharge unit 25 includes a pipe 25a, a pressure adjustment valve 25b provided in the middle of the pipe 25a, and a vacuum pump 25c. The chamber 21 is provided with a cleaning gas blowing section 26. A pair of cleaning gas blowing portions 26 are provided so as to sandwich the substrate holder 22 at substantially the same height as the upper surface of the substrate holder 22. The cleaning gas blowing section 26 is connected to the cleaning gas supply section via a pipe (not shown).

When forming the sealing film using the plasma CVD apparatus 20, the substrate 30 on which the first electrode, the light emitting layer, and the second electrode (not shown) are laminated is disposed on the substrate holder 22. Then, with the plasma CVD mask 11 placed on the substrate 30, the vacuum pump 25 c is operated to maintain the chamber 21 at a predetermined reduced pressure, and the reaction gas for film formation on the shower head 23, For example, a mixed gas of silane (SiH ₄ ) and nitrogen is supplied. The reaction gas is uniformly diffused from the gas introduction holes of the shower head 23 toward the substrate 30. Then, in a state where the pressure of the reaction gas introduced into the chamber 21 is controlled by the pressure regulating valve 25 b, the high frequency power supply RF is turned on to apply high frequency power to the space S between the shower head 23 and the substrate holder 22. . Then, the reaction gas is turned into plasma in the space S, a silicon nitride film is generated on the substrate 30, and a sealing film is formed at a position corresponding to each opening 12 a of the plasma CVD mask 11. The component of the sealing film is also deposited (attached) on the plasma CVD mask 11. If the amount of the adhesion of the sealing film adhering to the plasma CVD mask 11 is allowed to stand and the amount of adhesion increases, problems such as separation of the component of the sealing film adhering to the plasma CVD mask 11 occur. When the amount reaches a preset amount, the plasma CVD mask 11 is cleaned.

The plasma CVD mask 11 is also cleaned using the plasma CVD apparatus 20. When cleaning the plasma CVD mask 11, the plasma CVD mask 11 is placed on the substrate holder 22 with the cover 13 facing upward. Then, the vacuum pump 25 c is operated to keep the inside of the chamber 21 in a predetermined reduced pressure state, and the cleaning gas is supplied to the cleaning gas blowing section 26. Nitrogen trifluoride (NF ₃ ) is used as the cleaning gas (etching gas). In this embodiment, NF ₃ is supplied in a radicalized state in advance. Further, the high frequency power supply RF is turned on while the pressure of the cleaning gas introduced into the chamber 21 is controlled by the pressure regulating valve 25b.

NF ₃ introduced into the chamber 21 and converted into plasma generates fluorine free radicals that react with the silicon nitride film by an ion bombardment action to synthesize SiF ₄ and other volatile compounds. Then, the volatile compound is discharged from the chamber 21 by the vacuum pump 25c. The cleaning is completed faster as the portion near the blowing portion 26 of the cleaning gas.

  While the film component adhering to the metal mask main body 12 is subjected to the cleaning action, there is little adverse effect on the metal mask main body 12. However, if the film components are removed and then exposed to a cleaning gas, the metal mask body 12 deteriorates. The cleaning time is set to a time at which the cleaning of the portion farthest from the cleaning gas blowing portion 26 is completed. For this reason, when a sealing film is formed using a metal mask without the cover 13 and cleaning is performed on the metal mask to which film components are adhered, the portion of the metal mask close to the cleaning gas blowing portion 26 deteriorates. The mask replacement time is earlier.

  However, in this embodiment, since the sealing film is formed in a state where the cover 13 is disposed on the peripheral portion of the metal mask main body 12, no film component adheres to the peripheral portion of the metal mask main body 12. . When the plasma CVD mask 11 is cleaned, the cover 13 is placed on the peripheral edge of the metal mask main body 12 that is close to the cleaning gas blowing portion 26. Since the cover 13 is made of alumina ceramic, it does not deteriorate even when exposed to the cleaning gas for a long time.

According to this embodiment, the following effects can be obtained.
(1) The plasma CVD mask 11 includes a metal mask main body 12 whose outer shape is formed in a rectangular shape, and a ceramic cover 13 disposed on the periphery of the metal mask main body 12. Therefore, when the sealing film of the organic EL element is formed by the plasma CVD method, the plasma CVD mask 11 is used, and the film component adhering to the plasma CVD mask is cleaned using the plasma CVD apparatus 20. However, since the portion close to the cleaning gas blowing portion 26 of the metal mask main body 12 is covered with the cover 13, deterioration of the metal mask main body 12 is suppressed, and the life of the plasma CVD mask 11 is extended. The service life is extended about 2 to 3 times compared to a metal mask not using a ceramic cover.

  (2) The ceramic of the material of the cover 13 is alumina. The inside of the chamber 21 of the plasma CVD apparatus 20 is cleaned by supplying a cleaning gas. Alumina is used as a material for the inner surface of the chamber 21 and is a material suitable for cleaning. Accordingly, the cover 13 is smoothly cleaned.

  (3) The cover 13 is formed separately from the metal mask main body 12, and is used by being disposed on the metal mask main body 12 when using the plasma CVD mask 11. When the metal mask main body 12 and the cover 13 are integrated, if the metal mask main body 12 is deteriorated and needs to be replaced, the entire plasma CVD mask 11 needs to be replaced. Since it is a separate body, only the metal mask body 12 needs to be replaced.

  (4) Since the cover 13 is separate from the metal mask main body 12 and is disposed on the entire peripheral edge of the metal mask main body 12, it is easy to arrange and store it during use. This is because the cover 13 does not have to be disposed on the entire periphery of the metal mask main body 12 but only on a portion close to the cleaning gas blowing portion 26 (in this embodiment, the two metal mask main bodies 12 facing each other). Side) may be arranged. However, when the cover 13 is separated from the metal mask main body 12, in the configuration arranged only on two sides, one cover 13 is required for each side, and the parts of the plasma CVD mask 11 are necessary. This is because the number of points increases, and the labor for arranging and storing the plasma CVD mask 11 increases.

(5) Since radicals of nitrogen trifluoride (NF ₃ ) are supplied as the cleaning gas, the cleaning time can be shortened as compared with the case of supplying NF ₃ in a non-radical state.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The plasma CVD mask 11 may include a metal mask main body 12 and a ceramic cover 13 disposed on at least one side of the metal mask main body 12. For example, as the plasma CVD apparatus 20, when the cleaning gas blowing section 26 is provided at one location, the cover 13 may be provided at a position corresponding to one side of the metal mask main body 12, and the plasma CVD apparatus 20 of the above-described embodiment. Thus, when there are the blowout portions 26 on both sides of the substrate holder 22, the cover 13 may be disposed on two opposite sides as shown in FIG. However, since the metal mask main body 12 is thin, when the cover 13 is disposed only on one side of the metal mask main body 12, there is a possibility that a part of the metal mask main body 12 does not adhere to the substrate 30. Therefore, it is preferable that the cover 13 is disposed on two opposite sides even when the cleaning gas blowing portion 26 is provided at one location. That is, it is preferable that the cover 13 is disposed on two opposite sides of the metal mask main body 12 even when the portion to be covered by the metal mask main body 12 is one side.

  The plasma CVD mask 11 may be disposed so that the ceramic cover 13 of the plasma CVD mask 11 is closest to the cleaning gas blowing portion 26 of the plasma CVD apparatus 20 at least during cleaning. For example, as shown in FIG. 4, when the ceramic cover 13 is disposed on two opposite sides of the metal mask main body 12, the plasma CVD mask 11 is plasma CVD when the sealing film is formed. It is not necessary for the ceramic cover 13 of the mask 11 to be disposed so as to be closest to the cleaning gas blowing portion 26 of the plasma CVD apparatus 20. However, at the time of cleaning, it is necessary to be disposed so as to be closest to the cleaning gas blowing portion 26 of the plasma CVD apparatus 20.

  ○ Even when the cover 13 is configured to be disposed on all four sides that are the periphery of the metal mask main body 12, a frame whose outer shape is the same as the outer shape of the metal mask main body 12 as in the above embodiment. Instead of the body, the cover 13 may be configured such that the frame body can be disassembled into four rod-shaped bodies or plate bodies.

  The cover 13 may be integrally formed with the metal mask main body 12. The metal mask body 12 and the cover 13 are bonded by, for example, brazing. In this case, when the plasma CVD mask 11 is used for forming a sealing film, the trouble of disposing the plasma CVD mask 11 at a predetermined position in the chamber 21 is that the metal mask body 12 and the cover 13 are separate. Compared to the easier.

The plasma CVD mask 11 may be formed of a hexagonal shape, an octagonal shape, or the like instead of a rectangular shape as long as the outer shape of the metal mask body 12 is a polygonal shape.
The cover 13 may be made of ceramic, and the material thereof is not limited to alumina, and may be, for example, zirconia.

The metal mask main body 12 is not limited to a mask pattern having a shape having a plurality of openings 12a, and may be a frame having a single opening 12a.
The metal mask main body 12 and the cover 13 are not only placed on the substrate 30 but may be fixed to the substrate holder 22 with a pressing device or a gripping device.

  ○ As the mask 11 for plasma CVD, the metal mask main body 12 and the cover 13 do not always need to be used in pairs, and the metal mask main body 12 and the cover 13 that can cover the periphery thereof are provided. The cover 13 prepared separately and used at the time of forming the sealing film may be different from the cover 13 used at the time of cleaning.

The thin film formed by the plasma CVD apparatus 20 may be a thin film other than the sealing film of the organic EL element.
The plasma CVD apparatus 20 is not limited to the configuration provided with the shower head 23, and may be configured to supply the reaction gas from below or from the side of the substrate holder 22.

The plasma CVD apparatus 20 is not limited to a parallel plate type apparatus, and may be a dielectric plasma type apparatus, for example.
○ Cleaning gas is not limited to fluorine trinitride. For example, a fluorine compound such as CF ₄ , C ₂ F ₆ , C ₃ F ₈ , SF ₆ , a mixture of fluorine compounds, a mixture of O ₂ , H ₂ , or an inert gas is used. You may do it.

The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to claim 1 or 2, the cover is configured separately from the metal mask main body, and is disposed on the metal mask main body.

  (2) In the invention according to claim 1 or claim 2, the metal mask main body 12 has a rectangular outer shape, and the cover is disposed on at least two sides.

The perspective view of the mask for plasma CVD of one Embodiment. The disassembled perspective view of the mask for plasma CVD. The schematic block diagram of a plasma CVD apparatus. The perspective view of the mask for plasma CVD in another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Mask for plasma CVD, 12 ... Metal mask main body, 13 ... Cover.

Claims (4)

  A plasma CVD mask comprising: a metal mask body having an outer shape formed in a polygon; and a ceramic cover disposed on at least one side of the metal mask body.   The plasma CVD mask according to claim 1, wherein the ceramic is alumina.   A method for cleaning a plasma CVD mask, wherein when a thin film is formed by plasma CVD, a film is formed with a ceramic cover disposed at least at a part of the periphery of the metal mask. A method for cleaning a mask for plasma CVD, comprising: cleaning a metal mask with a ceramic cover disposed on at least a portion of the metal mask close to a cleaning gas outlet.   The method for cleaning a mask for plasma CVD according to claim 3, wherein the thin film formed by the plasma CVD is a sealing film of an organic electroluminescence element.

Images