JP4624824B2 - Metal mask manufacturing method and metal mask - Google Patents

Description

  The present invention relates to a metal mask manufacturing method and a metal mask used at the time of vapor deposition such as when manufacturing an organic EL display.

  A well-known organic EL display is a display that displays when an organic light emitting layer sandwiched between a cathode electrode and an anode electrode emits light. The organic light emitting layer includes a low molecular weight material and a high molecular weight material. The organic light emitting layer of a low molecular material is formed by vacuum deposition (see Non-Patent Document 1).

  Vapor deposition is performed by placing a mask sheet having an opening on the surface of a substrate such as glass. The organic material that has passed through the opening is deposited on the substrate.

  As shown in FIG. 7, the mask sheet 12 is in the form of a film made of nickel or a nickel-based alloy, and is used by being attached to the frame 14. As an attachment method, for example, there is a method of attaching the end of the mask sheet 12 to the frame 14 by spot welding 38 while applying tension to the mask sheet 12. In this specification, the metal mask 40 is obtained by attaching the mask sheet 12 to the frame 14 as described above.

By Koji Shinji “All about Organic EL” published by Nihon Jitsugyo Shuppan Co., Ltd. p80-85 February 20, 2003

  In order to manufacture a metal mask 40 with high dimensional accuracy, while adjusting the tension of the mask sheet 12 and the accompanying elongation of the mask sheet 12 and the deformation of the frame 14 due to the tension of the mask sheet 12 to an appropriate state at the same time, An advanced technique for fixing the seat 12 to the frame 14 is required. Therefore, the metal mask 40 used for the high-definition organic EL display has a drawback that the manufacturing yield is deteriorated.

  Further, when the position of the opening 34 is shifted due to the tension applied to the mask sheet 12, a defect occurs in the vapor deposition pattern of the organic light emitting layer to be vapor deposited, and the manufacturing yield of the display is deteriorated. In particular, in the case of a display with high definition, the production yield is greatly deteriorated.

  Further, when the mask sheet 12 is attached to the frame 14 by spot welding, the mask sheet 12 may be wrinkled. This is because the mask sheet 14 to which tension is applied is fixed at a plurality of points, and therefore the force generated at each point differs unless tension is applied evenly to the mask sheet 12. This wrinkle also shifts the position of the opening 34 and causes a defect in the vapor deposition pattern.

  An object of the present invention is to provide a metal mask manufacturing method and a metal mask that can correct the position of the opening even after the mask sheet is fixed to the frame. It is another object of the present invention to provide a metal mask manufacturing method and a metal mask capable of suppressing variations in tension of the metal mask.

The method of manufacturing a metal mask according to the present invention includes a step of fixing an end portion of a mask sheet having a plurality of openings to a frame, and irradiating the mask sheet with a pulsed laser so that the surface of the mask sheet is non-coated. Crystallizing, generating a metal oxide on the surface of the mask sheet, or both, and contracting the mask sheet to move the position of the opening.

The pulse width of the pulse laser is preferably 1 ns to 1 ms.

The pulse laser irradiation is preferably performed on a part of the mask sheet.

It is preferable that the tension applied to the mask sheet is greater after the mask sheet is irradiated with the pulse laser than before.

  In the present invention, since the position of the opening can be adjusted after the mask sheet is fixed to the frame, a metal mask with high dimensional accuracy can be easily manufactured. Moreover, wrinkles can be prevented from occurring by suppressing variations in the tension of the mask sheet or by partially adjusting the tension.

  A metal mask manufacturing method and a metal mask according to the present invention will be described with reference to the drawings. First, the manufacturing method of the metal mask 10 is demonstrated using FIG. 1 (a)-(c).

  (1) As shown in FIG. 1A, a mask sheet 12 having a plurality of openings and a frame 14 to which the mask sheet 12 is attached are prepared. (2) As shown in FIG. 1 (b), the end of the mask sheet 12 is fixed to the frame 14. (3) Check whether the opening of the mask sheet 12 is in a desired position. (4) As shown in FIG. 1C, if the position of the opening is shifted, the mask 18 is irradiated with the laser 18 to contract the mask sheet 12 and move the position of the opening.

  The mask sheet 12 prepared in the above (1) is made of nickel or a nickel-based alloy. An example of the nickel-based alloy is a nickel-cobalt alloy. The mask sheet 12 is manufactured by an electroforming method. The thickness of the mask sheet 12 is about 10 μm to 30 μm.

  In the fixing in (2) above, the mask sheet 12 is fixed to the frame 14 by spot welding. When fixing, a tension is applied to the mask sheet 12, but at this time, the tension is made weaker than the tension applied to the mask sheet 12 of the metal mask 10 to be finally manufactured. Highly accurate alignment is not required as compared with the prior art. This is because the position of the opening of the mask sheet 12 is moved by contraction in the above (4). Therefore, the mask sheet 12 can be easily fixed as compared with the conventional case.

  The laser source 16 of the laser 18 in the above (4) uses a pulse laser that performs pulse oscillation, for example, a YAG laser, a Ti sapphire laser, an excimer laser, etc. by direct modulation or Q switching. The spot of the laser 18 is adjusted using a condensing lens or the like so that the full width at half maximum (FWHM) is about 100 μm to 300 μm. The laser 18 has, for example, visible light (about 380 nm to 780 nm), an output of about 10 to 1000 mW, a pulse width of about 1 ns to 1 ms, and a repetition frequency of 100 Hz to 100 MHz.

  In many cases, irradiation of the laser 18 is performed on a part of the mask sheet 12. As shown in FIG. 2A, when a plurality of lasers 18 are irradiated onto the partial region 12a of the mask sheet 12, the partial region 12a contracts together with the irradiation region 18a, and the opening of the mask sheet 12 moves. Therefore, the opening of the mask sheet 12 can be moved to a desired position by adjusting the portion irradiated with the laser 18. Further, the irradiation conditions at that time, for example, the power density of the laser beam, the beam diameter, the irradiation time, the scanning speed, and the like may be determined so as to obtain a desired mask shrinkage amount by experiments.

  The irradiation position 18a of the laser 18 may be a continuous line with respect to the partial region 12a of the mask sheet 12, as shown in FIG.

  The reason why the mask sheet 12 contracts will be described. When the pulse laser 18 is irradiated onto the mask sheet 12, heat enters and exits at the irradiated portion. This heat entry and exit is rapid and rapid cooling. The surface of the mask sheet 12 is made amorphous by this momentary heat flow, and / or metal oxide is generated on the surface of the mask sheet 12. For this reason, volume shrinkage occurs in the vicinity of the surface of the mask sheet 12 irradiated with the laser, and the portion irradiated with the laser 18 shrinks. Therefore, the laser irradiation is usually performed until the surface of the mask sheet 12 is made amorphous and / or a metal oxide is formed on the surface of the mask sheet 12.

  As the laser 18, various lasers 18 can be used, but a pulsed laser is preferable. If the pulse width is too short, nickel may be peeled off and evaporated by ablation. If the pulse width is too long, the mask sheet 12 may be extended not by heat generation concentrated on the local area but by the dewarming / cooling over a wide area. From experiments, the pulse width is preferably about 1 ns to 1 ms.

  When the mask sheet 12 contracts, the tension applied to the mask sheet 12 after irradiation becomes larger than before irradiation with the laser 18. When the mask sheet 12 is fixed to the frame 14, it is not necessary to apply a uniform tension to the mask sheet 12.

  As described above, the metal mask 10 manufactured by the manufacturing method of the present invention is a frame 14 and a sheet-like metal fixed to the frame 14 and having a plurality of openings, and at least a part of the surface of the metal is not. And a mask sheet 12 that is crystalline, metal oxide, or both. Unlike the prior art, the surface of the mask sheet 12 is amorphous and / or has a metal oxide portion. As described above, the surface of the mask sheet 12 is laser-irradiated to make the surface of the mask sheet 12 amorphous and / or metal oxide, thereby forming the metal mask 10 with high dimensional accuracy.

  Next, an experimental result when the mask sheet 12 is irradiated with the laser 18 will be described. The following experimental results are experimental results regarding displacement in the Y-axis direction. The amount of displacement applied to the mask sheet 12 when the laser 18 is irradiated once on the entire surface of the mask sheet 12 is as shown in FIG. The unit of the numerical value in the figure showing the amount of displacement is μm, and indicates how much the displacement is in the Y-axis direction. A positive value indicates a displacement in the positive direction of the Y axis, and a negative value indicates a displacement in the negative direction of the Y axis. The laser 18 had an output of 70 mW, a wavelength of 530 nm, a pulse width of about 200 ns, a repetition frequency of 10 kHz, and a beam diameter of 0.3 mm (FWHM). Further, the irradiation position of the laser 18 was set at an equal interval of 0.3 mm with respect to the mask sheet 12, and the laser 18 was irradiated on the entire surface of the mask sheet 12 by scanning the laser in a predetermined direction. From FIG. 3, it can be seen that the mask sheet 12 contracted toward Y = 0. Note that it is considered that the same experimental results as described above can be obtained in the X-axis direction.

  If the amount of contraction of the mask sheet 12 by irradiating the laser 18 is obtained, the amount of contraction can be fed back to fix (2) above. When the fixing of (2) is performed, the amount of contraction of the mask sheet 12 is taken into consideration, and the tension applied to the mask sheet 12 is weakened compared to the conventional case, and the mask sheet 12 is fixed. That is, the mask sheet 12 is fixed to the frame 14 so that the position of the opening of the mask sheet 12 is shifted from the center of the mask sheet 12 toward the frame 14.

  For example, as shown in FIG. 4, the mask sheet 12 is fixed while shifting in the Y-axis direction away from Y = 0. FIG. 4 is a diagram showing a shift in the Y-axis direction of the mask sheet when the mask sheet is fixed to the frame, and a positive numerical value indicates a shift in the positive direction of the Y-axis from a desired position. A negative numerical value indicates a deviation in the negative direction of the Y axis from the desired position. When the entire surface of the mask sheet 12 is irradiated with laser, the mask sheet contracts. This is shown in FIG. The numerical values in FIG. 5 are the same as those in FIG. 4, and a positive numerical value indicates that the position is shifted in the positive direction of the Y axis from the desired position, and a negative numerical value is shifted in the negative direction of the Y axis from the desired position. It shows that. The laser has an output of 70 mW, a wavelength of 530 nm, a pulse width of about 200 ns, a repetition frequency of 10 kHz, a beam diameter of 0.3 mm (FWHM), and the number of irradiations is four. Further, the irradiation position of the laser 18 was set to an equal interval of 0.3 mm with respect to the mask sheet 12, and the laser 18 was scanned in a predetermined direction so as to irradiate the substantially entire surface of the mask sheet 12. According to FIG. 5, it can be seen that the deviation is approximately 10 μm or less by laser irradiation. Any deviation of 10 μm or less can be used as a metal mask 10 for manufacturing a high-definition organic EL display.

  As described above, by optimizing the position and intensity of laser irradiation, it is possible to highly correct misalignment, and the metal mask 10 with high dimensional accuracy can be obtained. Thus, the present invention is effective for manufacturing a high-definition organic EL display. Moreover, the manufacture of the high-definition metal mask 10 is easy, and deterioration of the manufacturing yield can be prevented.

  As mentioned above, although this invention was demonstrated, this invention is not limited to embodiment mentioned above. For example, the form when the mask sheet is fixed to the frame may be as shown in FIG. The first side 22a of the frame is different from the second side 22b opposite to the first side 22a. The other side connecting the first side 22a and the second side 22b is configured such that the first side 22a and the second side 22b are movable. The first side 22a is for fixing the mask sheet 12, and the second side 22b is for correcting wrinkles and displacement of the mask sheet 12.

  The first side 22a includes first and second plate-like bodies 24a and 24b sandwiching the mask sheet 12, and a first fixing portion 26a and a first fixing portion 26a having an L-shaped cross section for fixing the first plate-like body 24a. And a second fixing portion 26b having a substantially L-shaped cross section sandwiching the first and second plate-like bodies 24a and 24b with the first fixing portion 26a. Screws 28a and 30a are used to fix the first plate-like body 24a and the first fixing part 26a and to fix the first fixing part 26a and the second fixing part 26b. The first plate-like body 24a and the second plate-like body 24b are composed of magnets. The second fixing portion 26b is configured by a curved portion where the mask sheet 12 is in contact, and prevents the mask sheet 12 from being damaged or torn.

  The second side 22b includes third and fourth plate-like bodies 24c and 24d that sandwich the mask sheet 12, and a third fixing portion 26c and a third fixing portion 26c that are substantially L-shaped in cross section and fix the third plate-like body 24c. The third and fourth plate-like bodies 24c and 24d are sandwiched between and the third fixing portion 26c includes a fourth fixing portion 26d fixed so as to be adjustable in position. As shown in FIG. 6, the third and fourth plate-like bodies 24c and 24d are fixed in the vertical direction, and the third fixing portion 26c and the fourth fixing portion 26d are fixed in the horizontal direction. Screws 28b and 30b are used for fixing the third plate-like body 24c and the third fixing portion 26c, and fixing the third fixing portion 26c and the fourth fixing portion 26d. The third plate-like body 24c and the fourth plate-like body 24d are composed of magnets. The fourth fixing portion 26d is configured by a curved portion where the mask sheet 12 is in contact, and prevents the mask sheet 26 from being damaged or torn. There are a plurality of fixing screws 28a and 28b and tension adjusting screws 30a and 30b.

  The mask sheet 12 is fixed by (a) sandwiching the end portion of the mask sheet 12 between the first and second plate-like bodies 24a and 24b of the first side 22a. When sandwiched, the mask sheet 12 is fixed between the first and second plate-like bodies 24a and 24b by the attractive force of the magnet. (B) The first fixing portion 26a and the first plate-like body 24a are fixed by the screw 28a. (C) The first and second plate-like bodies 24a and 24b are sandwiched between the first fixing portion 26a and the second fixing portion 26b, and the first fixing portion 26a and the second fixing portion 26b are fixed by the screw 30a. The mask sheet 12 is fixed to the first side 22a in the above steps (a) to (c).

  (D) The end portion of the mask sheet 12 is sandwiched between the third and fourth plate-like bodies 24c and 24d. When sandwiched, the mask sheet 12 is fixed between the third and fourth plate-like bodies 24c and 24d by the attractive force of the magnet. (E) The third plate-like body 24c and the third fixing portion 26c are fixed with screws 28b. (F) The third and fourth plate-like bodies 24c and 24d are sandwiched between the third fixing portion 26c and the fourth fixing portion 26d, and the gap 32 between the third fixing portion 26c and the fourth fixing portion 26d is adjusted by the screw 30b. Meanwhile, the third fixing portion 26c and the fourth fixing portion 26d are fixed.

  The tension applied to the mask sheet 12 can be changed by the adjusting screw 30b, and the positional deviation of the opening 34 of the mask sheet 12 can be adjusted. If it is fixed at a plurality of points by spot welding, the mask sheet 12 is likely to be wrinkled. However, in the case of the configuration shown in FIG. Therefore, the mask sheet 12 is difficult to be wrinkled.

  The first side 22a is used for fixing the mask sheet 12, and the second side 22b is used for adjusting the tension of the mask sheet 12. However, the mask sheet 12 is fixed to the second side 22b, and the screw 30a of the first side 22a is used. The tension of the mask sheet 12 may be adjusted by adjusting. Further, the tension of the mask sheet 12 may be adjusted using the screws 30a and 30b of the first and second sides 22a and 22b.

  The metal mask 12 shown in FIG. 6 may be irradiated with the laser 18 to adjust the opening 34 of the mask sheet 18 to a desired position. Positioning can be performed with higher accuracy than in the case of FIG.

In addition, the present invention can be implemented with various improvements, modifications, and changes based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
For example, when a layer made of a material that easily absorbs laser light is formed on the surface of the mask sheet 12, and the portion is irradiated with laser light, heat generation due to absorption of the laser light is large, and the mask sheet is efficiently contracted. Can be made. As materials that easily absorb laser light, those used for organic EL materials of organic EL elements, especially copper phthalocyanine and Alq3, etc., have relatively large light absorption, making it easy to effectively use the heat generated by laser light. Since it evaporates itself by laser irradiation, it is preferable that it does not remain after laser irradiation. The layer thickness may be about 10 nm to 3000 nm.

It is a figure which shows the manufacturing method of the metal mask of this invention, (a) is the figure which prepared the mask sheet | seat and the flame | frame, (b) is the figure which fixed the mask sheet | seat to the flame | frame, (c) is a mask sheet | seat. It is a figure which irradiates with a laser. It is a figure which shows the irradiation position of a laser, (a) is a figure in the case of irradiating at equal intervals, (b) is a figure which irradiates a laser on a line. It is a figure which shows the contraction amount of irradiation per time by laser irradiation. It is a figure which shows the shift | offset | difference of the Y direction of a mask sheet when a mask sheet is fixed to a flame | frame. It is a figure which shows the shift | offset | difference of the Y-axis direction when a laser is irradiated to the mask sheet | seat of FIG. It is a figure which shows the other form when fixing a mask to a flame | frame. It is a cross-sectional perspective view which shows the conventional metal mask.

Explanation of symbols

10: Metal mask 12: Mask sheet 14: Frame 16: Laser source 18: Laser

Claims (4)

Fixing the edge of the mask sheet having a plurality of openings to the frame;
The mask sheet is shrunk by irradiating the mask sheet with a pulsed laser to make the surface of the mask sheet amorphous, generate a metal oxide on the surface of the mask sheet, or both. And moving the position of the opening,
A method of manufacturing a metal mask including: The method of manufacturing a metal mask according to claim 1, wherein the pulse width of the pulse laser is 1 ns to 1 ms. The method of manufacturing a metal mask according to claim 1, wherein the irradiation of the pulse laser is performed on a part of the mask sheet. 4. The method of manufacturing a metal mask according to claim 1, wherein the tension applied to the mask sheet is greater after the mask sheet is irradiated with the pulse laser than before.

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