JP2013209697A6 - Film forming apparatus and film forming method - Google Patents

Abstract

When forming a deposited film of an organic EL device, the mask and the substrate are brought into close contact with each other without a gap between the mask and the substrate so that an unnecessary inclined film is not formed.
A film forming apparatus forms a vapor deposition material sprayed from a vapor deposition source through a mask on an organic EL device substrate carried into a vacuum chamber. The surface of the substrate support means that holds the substrate vertically and that faces the substrate was formed as a curved surface that protruded toward the substrate.
[Selection] Figure 1

Description

  The present invention relates to a film forming apparatus and a film forming method for forming a film in a vacuum chamber, and more particularly to a film forming apparatus and a film forming method suitable for forming an organic EL device.

  A conventional method for manufacturing an organic EL device is described in Patent Document 1. In the method of manufacturing an organic EL device described in this publication, in order to produce an organic EL device economically with little material loss, N substrates (N is 2 or more) are accommodated in a vacuum chamber. During deposition of the first substrate, the Nth substrate is carried in, and during deposition of the second substrate, the first substrate is carried out of the vacuum chamber. Hereinafter, the efficiency of film formation is improved by repeating this procedure. Therefore, the vacuum chamber is divided into a plurality of parts.

JP 2010-86956 A

  In the conventional organic EL manufacturing method described in Patent Document 1, since the vacuum chamber is divided into a plurality of parts and the operations in the divided chambers are different, one substrate is subjected to the other substrate during vapor deposition. Can be carried in or out, and the film forming efficiency is improved. However, in the method described in this publication, for alignment between the substrate and the mask, after the substrate is upright, the alignment camera is used to image the alignment mark provided on the mask and the substrate, and the alignment mechanism is used to move the mask for alignment. However, the degree of adhesion between the mask and the substrate in actual alignment is not sufficiently considered.

  Generally, a mask has a mask sheet having a thickness of several tens of μm with a minute hole in a film forming portion, and a strong metal frame (mask frame) for holding the mask sheet on the outer periphery of the mask sheet. Is provided. The metal frame and the mask sheet are joined by welding and are collectively referred to as a mask.

  By the way, in forming the organic EL film or the like, it is important how faithfully the deposited film is formed in the hole of the mask arranged on the front surface of the substrate. Although the mask and the substrate are mechanically in close contact with each other, in reality, the substrate support plate and the mask frame for holding the substrate are distorted during component processing, and the entire surface of the substrate and the mask cannot be in close contact with each other. . In such a case, when the substrate surface after vacuum deposition is observed, a film having a substantially uniform thickness is formed by tracing the hole formed in the mask, while the film thickness formed in the hole portion around the hole. Compared to this, a very thin slope-like film is formed. The sloped film may have a maximum width of several tens of μm or more.

  Since organic molecules are ejected from the evaporation source with a constant ejection angle, the larger the gap between the mask and the substrate, the wider the film is formed, and the inclined film is formed in a wide area. In recent years, a high-definition display with a small screen has been demanded, and the density of pixel arrangement (PPI: pixel per inch) has increased, and is expected to increase to about 300 PPI. On the other hand, since the area of the film to be formed tends to be large and high luminance tends to be ensured, for example, the interval between the R light emitting film and the G light emitting film is narrowed, and the sloped film is required to be as small as possible. Has been.

  In the case of a display, when controlling the current to emit each color, the film thickness in the vicinity of the sloped film becomes thin, the luminance becomes nonuniform, and the deterioration is fast, so that it cannot be used as an effective film. Therefore, there is a strong demand to make the formation of the sloped film as small as possible by bringing the mask and the substrate into close contact with each other.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to form a mask and a substrate so that an unnecessary inclined film is not formed when forming a vapor deposition film in a film forming apparatus and a film forming method. The mask and the substrate are brought into close contact with each other. Another object of the present invention is to bring a mask and a substrate into close contact in an organic EL film forming apparatus and film forming method.

  A feature of the present invention that achieves the above object is that in a film forming apparatus for forming a deposition material sprayed from an evaporation source through a mask on a substrate for an organic EL device carried into a vacuum chamber, the substrate is placed vertically. The surface of the substrate supporting means to be held facing the substrate is a curved surface convex toward the substrate.

  In this feature, a cushioning sheet made of silicon rubber may be disposed between the substrate support means and the substrate, and a cushioning material made of silicon rubber is disposed at the upper end portion and the lower end portion of the substrate support means. May be. Further, a large number of protrusions may be arranged at intervals on the substrate-side surface of the substrate support means.

  Another feature of the present invention that achieves the above object is that an organic EL device substrate is carried into a vacuum chamber in a horizontal state, and then the substrate is held in a vertical state, and the evaporation source of the substrate held in the vertical state A substrate support plate composed of a curved surface disposed on the back surface, which is the surface opposite to the surface facing the substrate, is pressed against the substrate side, and the mask sheet of the mask disposed on the front surface side of the substrate is copied to this substrate shape. It is to let you let it.

  In this feature, it is preferable that the substrate-side surface of the substrate support plate has a curved surface convex toward the substrate, and the mask sheet follows the shape of the surface of the substrate facing the mask sheet.

  According to the present invention, since the surface of the substrate support plate disposed on the back surface of the substrate is a smooth curved surface, the film forming method and the film forming apparatus do not produce an unnecessary inclined film when forming the vapor deposition film, The gap between the mask and the substrate is eliminated, and the mask and the substrate are in close contact with each other. In the organic EL film forming apparatus and film forming method, the substrate and the mask are deformed following the substrate support plate, so that the mask and the substrate can be in close contact with each other.

It is the front view (a) which shows the detail of one Example of the board | substrate support plate used for the film-forming apparatus which concerns on this invention, and its partial enlarged view (b). It is a figure explaining the effect | action of the board | substrate support plate shown in FIG. 1, and is a longitudinal cross-sectional view. It is a longitudinal cross-sectional view of one Example of the film-forming apparatus which concerns on this invention incorporating the board | substrate support plate shown in FIG. It is a perspective view of the principal part of the film-forming apparatus shown in FIG. It is a figure which shows an example of the mask used for the film-forming apparatus which concerns on this invention.

  Embodiments of a film forming apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view (FIG. 1A) and a partially enlarged view (FIG. 1B) of an embodiment of a substrate support plate used in a film forming apparatus. FIG. 2 is a longitudinal sectional view for explaining the operation of the substrate support plate shown in FIG. 3 is a longitudinal sectional view of an embodiment of the film forming apparatus incorporating the substrate support plate shown in FIG. 1, FIG. 4 is a perspective view of the main part of the film forming apparatus, and FIG. It is a figure which shows an example of the mask to be used.

  First, the outline of the film forming apparatus 100 according to the present invention will be described with reference to FIGS. In the following description, film formation using an organic EL device will be described. However, it goes without saying that the present invention is not limited to an organic EL device but can be applied to a normal EL device or the like. Moreover, the board | substrate 6 demonstrated by a present Example is the 5th-6th generation, and also becomes a magnitude | size of 1500 mm x 1800 mm.

The film forming apparatus 100 includes a vacuum chamber 1 that is evacuated by a vacuum pump (not shown), and a gate valve 10 that opens and closes the vacuum chamber 1 when the substrate 6 is loaded into and transported to the vacuum chamber 1. During film formation by the film forming apparatus 100, the inside of the vacuum chamber 1 is partitioned by the gate valve 10 and maintained at a pressure on the order of 10 ⁻⁵ Pa.

  The substrate 6 is guided in a horizontal state from the outside of the apparatus to the vacuum chamber 1 using a conveying means (not shown). And it mounts on the board | substrate holding means 90 provided so that a board | substrate can be mounted and it can rotate. The substrate holding means 90 is connected to a rotation mechanism 92 fixed in the vacuum chamber 1 and can be rotated 90 degrees from a horizontal position to a vertical position by the rotation mechanism 92. The substrate holding means 90 has a substrate support plate 91 that holds the substrate 6 and forms a substrate mounting surface. In order to prevent the temperature of the substrate 6 from excessively rising during film formation, the substrate support plate 91 has cooling means, for example, a cooling channel formed therein, and is also called CP (cooling plate). An alignment camera 86 is attached in the vicinity of the positions of the upper and lower ends of the substrate support plate 91 when the substrate 6 is rotated and positioned in the vertical direction.

  A mask 81, which will be described in detail later, is held vertically via a holding means fixed to the vacuum chamber 1 so as to face the position where the substrate 6 is rotated to be in a vertical state. That is, the mask 81 is fixedly held by the mask holder 89 at the peripheral portion on the back side (the side opposite to the side facing the substrate 6). The upper part of the mask holder 89 is connected to an alignment driving unit 83 in which a motor is attached to the outside of the vacuum chamber 1.

  An evaporation source 71 extending in the left-right direction (Y direction in the figure) is arranged at a distance from the mask 81. The evaporation source 71 is movable in the vertical direction. The movement of the evaporation source 71 in the vertical direction and the adjustment of the alignment of the mask 81 are executed according to instructions from the controller 200.

  Here, details of the alignment will be described with reference to FIG. Although FIG. 4 shows a case where two substrates 6 can be attached to the left and right, the following description can be similarly applied even when only one substrate 6 can be attached. This is a case where the right substrate 6 is aligned. The substrate 6 transported into the vacuum chamber 1 is initially in a horizontal state. Since it is held by the substrate support plate 91, the substrate 6 is erected vertically without sliding down using the rotation mechanism 92.

  A window (opening) 85 as an alignment mark is formed at the corner of the mask 81. The alignment mark provided on the substrate 6 and the window 85 are imaged by the alignment camera 86 to perform alignment. Based on this imaging, the alignment driving unit 83 adjusts the position of the mask 81, and positioning of the mask 81 and the substrate 6 is executed. When the positioning is completed, the evaporation source 71 is moved to perform vapor deposition.

  In the mask 81 for vapor deposition for producing the substrate 6 having a high PPI, a rectangular hole is formed. The many holes are formed by etching or the like. The mask sheet 81a in which a large number of holes are formed is welded and fixed to the mask frame 81b by applying tension. The mask frame 81b has a size corresponding to the substrate 6 because the size of the substrate 6 has reached 1500 mm × 1800 mm in the fifth to sixth generations. For this reason, deformation of several hundred μm occurs due to processing errors in the manufacturing process. At the time of vapor deposition, the mask frame 81b is pressed against and held by the mask fixing plate of the apparatus, but it has been difficult to completely force the deformation generated in the manufacturing process.

  Conventionally, the adhesion between the glass substrate and the thin plate mask has been sufficiently studied. However, when the substrate after film formation is examined, a sloped film is often formed. One reason for this is that the present inventors consider that a very fine gap is formed between the glass substrate 6 and the thin mask 81, and the gap is made as zero as possible. .

  FIG. 1 and FIG. 2 show the substrate support plate 91 in detail. 1A is a front view and a longitudinal sectional view of the substrate support plate 91, and FIG. 1B is a detailed plan view of the portion A in FIG. 1A and a longitudinal sectional view thereof. 2A is a vertical cross-sectional view of the substrate 6 and the mask 81 before alignment, and FIG. 2B is a view of the substrate 6 and mask 81 after alignment.

  The substrate support plate 91 disposed on the back side of the substrate 6 acts to press the substrate 6 against the mask sheet 81 from the back side during the alignment. Therefore, the mask sheet 81 a is slightly deformed so as to follow the substrate 6. Since the substrate 6 is made of glass, it is held vertically with a slight deformation.

  The substrate-side surface of the substrate support plate 91 can be a curved surface that is convex toward the substrate 6 as a whole. Here, innumerable protrusions 91b having a width W and a height h are conventionally formed on the surface of the substrate support plate 91 at intervals c. The protrusion 91b prevents the resistance of the substrate 6 from increasing when the substrate 6 is brought into close contact with the substrate support plate 91 when the substrate 6 is moved to another vacuum chamber 1 and the substrate 6 is peeled off. Formed to prevent electrification when peeled.

  By making the shape of this protrusion 91b part into a curved surface as a whole, the substrate support plate 91 can be brought into close contact with the glass substrate 6. In this embodiment, the mask 81 and the substrate 6 are adhered in the longitudinal direction of the hole having a curvature. The curvature of the protrusion 91b is preferably selected so as to be a tension applied to the mask sheet 81a when the mask 81 is made to follow the substrate support plate 91. For example, it may be selected so that the change in projection height that occurs when the mask 81 follows the substrate support plate 91 is about 500 μm. That is, the curvature radius is about 560 m.

  Conventionally, the substrate 6 and the mask 81 are kept vertical, and the substrate 6 and the mask 81 are uniformly adhered. Therefore, attempts have been made to bring both the substrate 6 and the mask 81 as close as possible to zero flatness. However, it is practically impossible to make the flatness of both the substrate and the mask 81 zero. According to the present embodiment, even if a concave portion is locally present on the substrate support plate 91 having a curved surface, the substrate 6 forms a shape having no concave portion with its own rigidity. Further, since the mask 81 has a rigidity much smaller than the rigidity of the substrate 6, the mask 81 can be made to follow the substrate 6. In addition, since the mask 81 is made to follow the substrate 6, the substrate 6 and the mask 81 can be brought into close contact with each other without using high-precision components and apparatuses.

  Since the substrate support plate 91 has a curved shape, and the substrate 6 and the mask 81 follow the curved surface, the hole long side direction of the mask 81 (vertical direction in FIG. 5) indicates the degree of adhesion between the mask 81 and the substrate 6. Will improve. However, there is a possibility that the upper and lower ends of the mask 81 remain affected by deformation due to processing errors, assembly errors, and the like in the width direction (left and right direction in FIG. 5) of the mask frame 81b.

  Therefore, a buffer sheet 98 made of silicon rubber or tetrafluoroethylene resin is disposed on the entire surface of the substrate support plate 91 or on the upper and lower ends. By pressing the upper end portion and the lower end portion of the substrate 6 with the buffer sheet 98, the substrate 6 can be made to follow the mask frame 81b also in the width direction of the mask 81 (the left-right direction in FIG. 5).

  If the buffer sheet 98 is also provided at the center of the mask 81, the repulsive force of the buffer sheet 98 may increase the tension of the mask 81. However, the repulsive force of the buffer sheet 98 is increased at the upper and lower ends of the substrate 6. The high rigidity mask frame 81b receives and tension does not increase. Moreover, since the mask 81 is made to follow the shape of the board | substrate 6, even if it presses the width direction (left-right direction of FIG. 5) of the mask 81 using the buffer sheet 98, the effect which improves adhesiveness is not impaired.

  In the embodiment shown in FIG. 2, the cross-sectional shape of the surface protrusion of the substrate support plate 91 is a convex shape toward the glass substrate 6, but the radius of curvature is the amount of pushing that follows the mask sheet 81a. And the correlation of the mask size. In the case where priority is given to close contact, the shape of the curved surface may be a spherical surface, and may be an elliptical spherical surface or an egg shape. However, it is desirable that there is no concave surface. Further, the thickness of the buffer sheet 98 is desirably about 5 mm. Further, the curved surface of the substrate support plate 91 is preferably a curved surface convex not only in the vertical direction but also in the horizontal direction in the glass substrate side. However, the effect of the present invention can be obtained even in a curved surface only in the vertical direction.

  DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 6 ... Board | substrate, 10 ... Gate valve, 71 ... Evaporation source, 81 ... Mask, 81a ... Mask sheet, 81b ... Mask frame, 83 ... Alignment drive part, 84 ... Alignment mark, 85 ... Window, 86 ... Alignment camera 89 ... Mask holder 91 ... Substrate support plate 91b ... Projection 92 ... Rotating mechanism 98 ... Buffer sheet 100 ... Film forming apparatus 200 ... Controller

Claims (6)

In a film forming apparatus for forming a vapor deposition material sprayed from an evaporation source through a mask on an organic EL device substrate carried into a vacuum chamber,
A film forming apparatus, wherein a surface of the substrate supporting means that holds the substrate vertically is opposed to the substrate with a curved surface convex toward the substrate.   2. The film forming apparatus according to claim 1, wherein a cushioning sheet made of silicon rubber is disposed between the substrate support means and the substrate.   2. The film forming apparatus according to claim 1, wherein a cushioning material made of silicon rubber is disposed between the substrate support means and the substrate at an upper end portion and a lower end portion of the substrate support means.   3. The film forming apparatus according to claim 1, wherein a plurality of protrusions are arranged at intervals on the substrate side surface of the substrate support means.   A substrate for organic EL device is carried into a vacuum chamber in a horizontal state, and then the substrate is held in a vertical state. The back surface is a surface opposite to the surface facing the evaporation source of the substrate held in the vertical state. The substrate support plate, which is arranged on the side and is configured by a curved surface, is pressed against the substrate side so that the mask sheet of the mask arranged on the front side of the substrate follows the substrate shape. Membrane method.   6. The substrate-side surface of the substrate support plate is a curved surface convex toward the substrate side, and the mask sheet is made to follow the shape of the surface of the substrate facing the mask sheet. The film-forming method of description.

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