JP2007287943A - Alignment method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an accuracy of alignment between a substrate and a mask for film forming. <P>SOLUTION: Contacting a central part of the side edge of a substrate 5 to a protrusion 3 provided to a substrate holder 1 and retaining the substrate 5 in a convex shape prevent the deflection caused by its own weight of the substrate 5. An actuator 4 for the alignment arranges an alignment mark 5a on the convex edge line of the substrate 5 held on the substrate holder 1. No fluctuation in position of the alignment mark 5a between at the time of alignment of the substrate 5 and the mask 6, and at the time of close contact of the substrate 5 and the mask 6 after the alignment, improve the alignment accuracy. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an alignment method and apparatus for aligning a substrate and a mask using alignment marks in a film forming apparatus used for manufacturing an organic EL element (organic light emitting element).

  Conventionally, various sizes of flat panel display devices on which organic EL elements are mounted have been manufactured. Recently, in order to stabilize quality, reduce costs, and improve production efficiency, the size of a substrate used for a display has been increased. , Has come to become larger.

  As the board size becomes larger, the deflection of the board due to its own weight increases, and if the board and the mask are aligned in the state where the weight of the board is deflected, the alignment accuracy deteriorates. As a result, the yield is reduced.

As disclosed in Patent Document 1, the substrate holder is formed in a convex shape in advance using an elastic body, and when the substrate is placed, as disclosed in Patent Document 1, A method of holding a substrate in a substantially flat shape by deforming the substrate holder is known.
Japanese Patent Laid-Open No. 2003-258078

  However, according to the above prior art, the substrate holder has a convex shape in advance, but when the substrate is placed, the substrate holder is elastically deformed by the weight of the substrate, so that the substrate is maintained and held in a stable shape. I can't.

  In general, when an end of a substrate of about 360 mm × 460 mm or more is supported, depending on the thickness of the substrate, for example, when a substrate having a thickness of about 0.7 mm is used, the self-weight deflection increases. As a result, when the position of the alignment mark on the substrate is observed for alignment between the substrate and the mask, and when the substrate is placed on the mask, the alignment mark position is different, so the alignment accuracy deteriorates. . In other words, there is a problem that when the substrate is placed on the mask, there is no self-weight deflection of the substrate, so that it does not match the state when the alignment mark is detected. As described above, the tact is increased due to the difficulty in maintaining the alignment accuracy.

  The present invention has been made in view of the above-mentioned unsolved problems of the conventional technology, and increases the rigidity of the substrate in the direction of its own weight deflection, and the position of the substrate and the mask that can avoid a decrease in alignment accuracy due to its own weight deflection. It is an object of the present invention to provide a combination method and apparatus.

  The alignment method of the present invention is an alignment method for aligning a film-forming substrate and a mask, in a state where the substrate is deformed so as to have a convex shape having a ridge line at the center, Detecting the alignment mark of the substrate; detecting the alignment mark of the mask; and relatively moving the substrate and the mask so as to match the detected alignment mark of the substrate and the alignment mark of the mask. And a step of making it.

  If the substrate is held in a convex shape, the substrate will not be bent by its own weight, and the accuracy of alignment between the substrate and the mask will not be reduced even when the substrate size is large.

  In addition, by holding the substrate in a convex shape and detecting the alignment mark of the substrate provided on the ridgeline, the alignment with the mask can be performed with the same accuracy as the alignment in the state where there is no self-weight deflection of the substrate. it can.

  Further, when the substrate is held in a convex shape on a support member such as a rigid substrate holder, and the outer shape of the substrate is regulated by positioning means such as positioning pins to detect the alignment mark, the substrate holding means for the substrate It becomes easy to input to This can contribute to shortening the tact time in alignment. Even in the subsequent alignment operation, good accuracy can be maintained.

  In addition, by placing the substrate in advance on a support member provided with positioning means and transporting it to the alignment device as it is, even if it is a large substrate, it is stable and there is no occurrence of breakage or cracking, In addition, it can be transported at a higher speed than when the substrate is transported alone.

  As a result, the tact can be further shortened and the conveyance efficiency can be improved.

  The best mode for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a substrate holder 1 that is a support member of a substrate holding means has a pair of protrusions (projecting members) 3 on the side edges of the opening 2, and the substrate 5 is held by the alignment actuator 4. When fixed to 1, the protrusion 5 holds the substrate 5 in a convex shape as shown. By thus deforming the substrate 5 into a convex shape, the substrate 5 is held so as not to be bent by its own weight, and the alignment mark 5a (see FIG. 3) disposed on the ridge line in the central portion of the convex shape is used. Alignment with the mask 6 is performed.

  After the alignment is performed in a state where there is no position error due to the bending of the substrate 5, as shown in FIG. 2, the substrate 5 and the mask 6 are brought into close contact with each other, and the alignment actuator 4 is retracted to the inoperative position. And the pattern film-forming of the organic light emitting layer (thin film layer) of an organic light emitting element is performed with the vapor deposition source which is not shown in figure.

  FIGS. 1 to 3 are diagrams for explaining the first embodiment. FIG. 3 shows that the substrate holder 1, the alignment actuator 4, the substrate 5 and the mask 6 in FIGS. 1 and 2 are separated from each other. It is a perspective view shown.

  The alignment actuator 4 is disposed at a position where the vicinity of the four corners of the substrate 5 can be clamped. As shown in FIG. 3, the alignment mark 5a is arrange | positioned on the board | substrate 5 on the centerline (AA line). An opening 2 is disposed at the center of the substrate holder 1, and a mask 6 can be disposed here. On the side edge of the substrate holder 1, projections 3 are provided at two locations for lifting the substrate 5 so that the center line becomes a ridgeline and supporting it in a convex shape.

  The mask 6 is obtained by fixing a foil including a pixel opening 6b on a frame having an alignment mark 6a. The alignment mark 6a of the mask 6 is disposed on the center line (BB line) of the mask 6. . When the alignment mark 5a of the substrate 5 and the alignment mark 6a of the mask 6 match, the pixel opening 6b of the mask 6 is in a positional relationship so as to be aligned with a predetermined position of the substrate 5.

  Below the mask 6, there is a vapor deposition source (not shown), and the entire film forming apparatus including the vapor deposition source and the alignment device is arranged in a vacuum chamber.

  The material of the substrate holder 1 is SUS or aluminum, and is constituted by a rigid body that is less bent than the substrate 5, and the smaller the amount of deflection of the substrate holder 1, the better. Furthermore, it is more preferable that the amount of bending of the substrate holder 1 is 1/5 or less of the amount of bending of the substrate 5.

  As shown in FIG. 1, the substrate 5 is placed on the substrate holder 1 by a conveying means such as a hand (not shown), and then the alignment actuator 4 is lowered to clamp the end of the substrate 5. At this time, as shown in FIG. 1, the substrate 5 is deformed into a convex shape upward by the height S of the protrusion 3 provided on the substrate holder 1 and the pressing force of the alignment actuator 4. Held.

  Thus, since the substrate 5 is deformed from a planar shape to a shape in which the center of the substrate along the line AA is convex upward, the rigidity of the substrate itself in the direction of gravity is increased, and as a result, It is possible to maintain a state in which the substrate 5 is hardly bent by its own weight.

  Since the alignment mark 5a of the substrate 5 is located on such a convex ridgeline, even when the substrate 5 is in a convex shape, the substantially flat surface is maintained at the position where the alignment mark 5a is disposed. As a result, the alignment mark 5a on the substrate 5 and the alignment mark 6a on the mask 6 can be well aligned.

  Next, the alignment operation will be described. A substrate 5 is held in a convex shape by the substrate holder 1, and the substrate holder 1 is installed on a main body (not shown). The mask 6 is installed on an actuator (moving means) in the main body, and can move in the mask in-plane direction (XY), the vertical direction (Z), and the in-plane rotation direction (θ). Yes.

  In this state, the position of the mask 6 is driven by the alignment mark observation optical system (detection means) having the CCD image pickup unit 7 and the lens 8 so that the alignment marks 5a and 6a of the substrate 5 and the mask 6 are matched. Align it.

  Next, a method for closely attaching the substrate 5 and the mask 6 after alignment will be described with reference to FIG. After the alignment mark observation optical system and the actuator that moves the mask 6 make the alignment marks 5a and 6a of the substrate 5 and the mask 6 coincide with each other, the mask 6 is raised in the Z-axis direction, and the mask 6 is moved to the substrate. 5 and contact. Thereafter, the positioning actuator 4 is raised in the Z-axis direction.

  As a result, the substrate 5 and the mask 6 are brought into close contact with each other as shown in FIG. In this tight contact state, the vapor deposition material from the vapor deposition source can be vapor-deposited on the substrate 5 in a predetermined pattern via the mask 6.

  In this embodiment, the substrate size is 370 × 460 mm and the height S of the protrusion 3 is 1.5 mm. However, the present invention is not limited to this. For example, a substrate having a size larger than this is used. May be.

  On the surface of the substrate, as a top emission type, a TFT driving circuit is patterned in advance, and a first electrode is disposed on the TFT driving circuit. On the first electrode, the organic light emitting layer R (red), G (green), and B (blue) are separated by mask vapor deposition using the above-described alignment method, and there is no color mixing of each color. It was possible to separate the light emitting layer.

  FIG. 4 shows a substrate holder 11 according to the second embodiment. The substrate holder 11 of this embodiment has a projection 13 similar to the projection 3 of Embodiment 1, and eight positioning pins 14 provided on the outer peripheral portion of the substrate holder 11 as positioning means for the substrate 5. I have.

  The substrate 5 is placed on the substrate holder 11, and the substrate 5 is positioned and placed at the center of the substrate holder 11 by the positioning pins 14. With the positioning pins 14, the alignment marks 5 a provided in the substrate 5 can be positioned on a line connecting the substrate center and the two protrusions 13.

  When the substrate 5 is supported in a convex shape on the substrate holder 11, a high positioning accuracy can be obtained by positioning using the alignment mark 5a on the convex ridge line.

  In FIG. 4, when the gap e in the X direction and the gap f in the Y direction between the positioning pins 14 and the substrate 5 are set to be about 0.2 mm, the installation of the substrate 5 is stabilized and the positioning accuracy is increased. It is known that it can be maintained. In addition, the said dimension is not limited to this.

  For example, when a substrate is mounted on a substrate holder outside the apparatus and the substrate holder on which the substrate is mounted is stored in a stock chamber or the like, the substrate holder can be sequentially loaded into a manufacturing apparatus or the like downstream thereof. As a result, it is possible to prevent accidents such as breakage or breakage of the substrate as compared with the case where the substrate alone is introduced into the apparatus, and it is also possible to shorten the tact time for substrate transportation and mounting.

  Note that the positioning pins that match the outer shape of the substrate were used as the substrate positioning means, but the present invention is not limited to this. For example, a rectangular block is provided on the substrate holder, and the substrate end portion is provided on the side surface thereof. It is also possible to employ a configuration in which positioning is performed by abutting.

  FIG. 5 shows a substrate holder 21 according to the third embodiment. On the side edge of the substrate holder 21, a convex portion 24 that is a protruding member having an arc-shaped cross section is provided, and the substrate 5 is a positioning actuator 4. Thus, a convex shape having a ridge line is formed following this circular arc.

  According to the present embodiment, an advantage that the substrate is more stably held on the substrate holder is added.

  FIG. 6 shows a substrate holder 31 according to the fourth embodiment. On the substrate holder 31, a protrusion 33, which is a protruding member, and an inclined convex portion 34 are provided. The substrate 5 is deformed in accordance with the inclined convex portion 34 with the portion in contact with the projection 33 as the apex by the operation of the positioning actuator 4 and becomes a convex shape.

  According to the present embodiment, the substrate can be stably held on the substrate holder, and the manufacturing of the inclined convex portion is relatively easy. Therefore, there are advantages that the manufacturing cost of the substrate holder can be suppressed.

  FIG. 7 shows a fifth embodiment, which uses a pair of substrate support bases (support members) 41a and 41b without using a substrate holder. The substrate support bases 41a and 41b are provided with projections 43a and 43b, respectively, whereby the substrate 5 can be supported in a convex shape.

  Each of the substrate support bases 41a and 41b is fixed to a main body (not shown) by screw fastening means passed through the fitting holes 42a and 42b.

  The mask 6 is placed on an actuator in the main body, and is thereby movable in the mask in-plane direction (XY), the vertical direction (Z), and the in-plane rotation direction (θ). The alignment is performed by moving the mask 6 so that the alignment marks 5a and 6a of the substrate 5 and the mask 6 are aligned by the same alignment mark observation optical system as in the first embodiment.

  In the first to fifth embodiments described above, the example in which the alignment operation is performed by moving the mask has been described. However, a method of performing alignment by fixing the mask and moving the substrate may be used.

  Also, the height of the protrusion can be set to an arbitrary height according to the substrate size to be used.

1 is a schematic elevation view showing an alignment apparatus according to Embodiment 1. FIG. FIG. 2 is a schematic elevation view showing a state in which the substrate and the mask are in close contact with each other in the apparatus of FIG. 1. It is a disassembled perspective view which decomposes | disassembles and shows the apparatus of FIG. FIG. 6 is a perspective view showing Example 2. 6 is a schematic elevation view showing Example 3. FIG. 6 is a schematic elevation view showing Example 4. FIG. It is a disassembled perspective view which decomposes | disassembles and shows Example 5. FIG.

Explanation of symbols

1, 11, 21, 31 Substrate holder 3, 13, 33, 43a, 43b Protrusion 4 Positioning actuator 5 Substrate 5a, 6a Alignment mark 6 Mask 14 Positioning pin 24 Convex portion 34 Inclined convex portion 41a, 41b Substrate support base

Claims (7)

An alignment method for aligning a deposition substrate and a mask,
A step of detecting an alignment mark of the substrate in a state where the substrate is deformed so as to have a convex shape having a ridge line at a center portion;
Detecting an alignment mark of the mask;
And a step of relatively moving the substrate and the mask so that the detected alignment mark of the substrate and the alignment mark of the mask coincide with each other.   The alignment method according to claim 1, wherein an alignment mark of the substrate is disposed on the convex ridgeline of the substrate. In an alignment apparatus that aligns a substrate for film formation and a mask,
Detecting means for detecting a relative position between the alignment mark on the substrate and the alignment mark on the mask; moving means for moving at least one of the substrate and the mask; and substrate holding for deforming and holding the substrate into a convex shape. An alignment device, wherein the substrate is deformed and held in a convex shape by the substrate holding means, and an alignment mark of the substrate is detected by the detection means.   The said board | substrate holding means has a supporting member which supports the said board | substrate, and the protrusion member arrange | positioned so that a part of side edge of the said board | substrate may be lifted from the support surface of the said supporting member. 3. The alignment apparatus according to 3.   The alignment apparatus according to claim 4, wherein the substrate holding means includes positioning means for positioning the substrate on the support surface.   A film forming method comprising: bringing a substrate and a mask aligned by the alignment method according to claim 1 or 2 into close contact with each other, and forming a thin film on the substrate through the mask.   3. A method of manufacturing an organic light emitting device, comprising: aligning a substrate and a mask by the alignment method according to claim 1; and depositing an organic light emitting layer on the substrate through the mask.

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