JP7748837B2 - Metal mask - Google Patents

Description

The present invention relates to metal masks such as vapor deposition masks used when forming the light-emitting layer of an organic EL element by a vapor deposition mask method, array masks used when mounting solder balls, and printing masks used when forming a print layer by a screen printing method.

In metal masks consisting of a mask body and a frame that supports the mask body in a stretched state, improving the flatness of the mask body is useful for improving the positional accuracy of the light-emitting layer and printing layer. The applicant previously proposed Patent Document 1 as a technology for improving the flatness of the mask body, which describes a vapor deposition mask consisting of a mask body with numerous independent vapor deposition through-holes formed in the pattern formation area, a frame positioned on the periphery of the mask body, and an electrodeposited metal layer (metal layer) that inseparably bonds the mask body and frame. The upper surface of the frame is provided with stress relief sections where the electrodeposited metal layer is separated. The mask body and electrodeposited metal layer are formed by electroforming.

JP 2007-280774 A

The metal mask of Patent Document 1 uses stress relief sections to relieve internal stress generated when forming the electrodeposited metal layer by electroforming, thereby preventing the mask body from waviness due to the internal stress of the electrodeposited metal layer and reducing the flatness of the mask body to some extent. However, because internal stress also occurs in the mask body formed by electroforming, it is difficult to completely relieve the internal stress of the mask body with a configuration such as Patent Document 1, in which stress relief sections are provided on the top surface of the frame. As a result, there is a risk that distortion will occur in the mask body due to expansion and contraction of the mask body, and the configuration of Patent Document 1 has limitations on improving the flatness of the mask body.

The present invention aims to obtain a metal mask with a mask body that has superior flatness by suppressing distortion of the mask body caused by internal stress.

The metal mask of the present invention comprises a mask body 2 made of a thin metal plate and having a pattern formation area 9 in which a large number of independent through-holes 8 are arranged, and a frame 3 having a mask opening 5 and supporting the mask body 2 with the pattern formation area 9 facing the mask opening 5. Furthermore, an easily stretchable portion 24 is provided between the pattern formation area 9 and the inner circumferential surface 15 of the mask opening 5.

The mask body 2 is formed smaller than the mask opening 5 and includes an inner pattern formation region 9 and an outer peripheral region 10 surrounding the pattern formation region 9. The mask body 2 and frame 3 are inseparably joined via a metal layer 4 that extends inward from the inner peripheral surface 15 of the mask opening 5 and reaches the outer peripheral region 10. An easily stretchable portion 24 is provided circumferentially in the outer peripheral region 10 and/or the metal layer 4 of the mask body 2.

The easily stretchable section 24 is formed by a large number of independent through-holes 25 that penetrate the mask body 2 and/or metal layer 4 from front to back.

The mask body 2 and the metal layer 4 are bonded together with the outer peripheral region 10 and the metal layer 4 overlapping on the front and back. The metal layer 4 includes a bonding portion 18 that overlaps the outer peripheral region 10 and a support portion 19 between the bonding portion 18 and the inner peripheral surface 15 of the mask opening 5, and an easily stretchable portion 24 is provided in the support portion 19.

The mask body 2 and metal layer 4 are bonded together with the peripheral region 10 and metal layer 4 overlapping on the front and back. The peripheral region 10 includes an outer peripheral portion 11 on the outer edge that overlaps with the metal layer 4, and an inner peripheral portion 12 between the outer peripheral portion 11 and the pattern formation region 9, and an easily stretchable portion 24 is provided in the inner peripheral portion 12.

The easily expandable section 24 is biased toward the metal layer 4.

The interior of the through-hole 25 is filled with a filler 26 made of a material with a lower elastic modulus than the material constituting the portion forming the easily expandable section 24.

In the metal mask of the present invention, an easily stretchable portion 24 is provided between the pattern formation region 9 of the mask body 2 and the inner circumferential surface 15 of the mask opening 5 formed in the frame 3. By providing the easily stretchable portion 24 between the pattern formation region 9 and the inner circumferential surface 15 of the mask opening 5 in this manner, the easily stretchable portion 24 expands and contracts, absorbing expansion and contraction of the mask body 2 due to internal stresses generated during the formation of the mask body 2 (thin metal plate). This reduces distortion of the mask body 2 (metal mask 1) caused by expansion and contraction of the mask body 2. Furthermore, the easily stretchable portion 24 provided between the pattern formation region 9 and the inner circumferential surface 15 of the mask opening 5—in other words, the easily stretchable portion 24 provided outside the pattern formation region 9 (area excluding the pattern formation region 9)—prevents the expansion and contraction deformation of the easily stretchable portion 24 from affecting the pattern formation region 9, thereby reducing distortion in the pattern formation region 9 of the mask body 2, which requires greater flatness. As described above, the present invention reduces distortion in the mask body 2, thereby enabling a metal mask 1 to be obtained that includes a mask body 2 with superior flatness.

When the mask body 2 and frame body 3 are inseparably joined via the metal layer 4 and the easily stretchable portion 24 is provided in the outer peripheral region 10 of the mask body 2 and/or the metal layer 4, the easily stretchable portion 24 can absorb the expansion and contraction of the mask body 2 and metal layer 4 due to internal stresses generated during the formation of the mask body 2 and metal layer 4, thereby preventing distortion of the mask body 2 caused by the expansion and contraction of the mask body 2 and metal layer 4. Furthermore, when the easily stretchable portion 24 is provided in a circumferential manner, the easily stretchable portion 24 can absorb the expansion and contraction of the entire periphery of the mask body 2 in a planar view, further preventing distortion of the mask body 2.

When the easily stretchable portion 24 is formed from a large number of independent through-holes 25 that penetrate the mask body 2 and/or metal layer 4 from front to back, forming a group of through-holes 25 allows the portion of the mask body 2 and/or metal layer 4 where the easily stretchable portion 24 is provided to have a mesh-like structure and be imparted with springiness, which can reliably absorb the expansion and contraction of the mask body 2 and metal layer 4. Furthermore, an easily stretchable portion 24 formed from a large number of independent through-holes 25 is advantageous in that it can exhibit a variety of springiness by changing the diameter and number of the through-holes 25.

The metal layer 4 includes a bonding portion 18 that overlaps the outer peripheral region 10 in the bonding region 20, and a support portion 19 between the bonding portion 18 and the inner peripheral surface 15 of the mask opening 5. When the easily stretchable portion 24 is provided in the support portion 19, the easily stretchable portion 24 can be provided using a simple manufacturing method that simply involves forming the through-hole 25 at the same time as forming the metal layer 4. Furthermore, the easily stretchable portion 24 provided in the support portion 19 can absorb expansion and contraction due to internal stress in both the mask body 2 and the metal layer 4 located inside the easily stretchable portion 24.

The peripheral region 10 includes an outer peripheral portion 11 on the outer edge side that overlaps the metal layer 4 in the bonding region 20, and an inner peripheral portion 12 between the outer peripheral portion 11 and the pattern formation region 9. If the easily stretchable portion 24 is provided in the inner peripheral portion 12, the easily stretchable portion 24 can be provided using a simple manufacturing method that simply involves forming through-holes 25 in the inner peripheral portion 12 at the same time as forming the mask main body 2. Furthermore, the easily stretchable portion 24 provided in the peripheral region 10 can efficiently absorb expansion and contraction of the mask main body 2, particularly in the pattern formation region 9.

When the easily stretchable portion 24 is biased toward the metal layer 4, the expansion and contraction deformation of the easily stretchable portion 24 can be more effectively prevented from affecting the pattern formation region 9, thereby further improving the flatness of the mask body 2 in the pattern formation region 9.

When the through-holes 25 are filled with a filler 26 made of a material with a lower elastic modulus than the material constituting the portion forming the easily expandable section 24, the vapor deposition material in the vapor deposition mask method or the printing material in the screen printing method can be prevented from passing through the metal mask 1 via the through-holes 25, thereby preventing the deposition of the vapor deposition material or the application of the printing material to unnecessary areas.

FIG. 2 is a vertical cross-sectional side view showing a main part of a metal mask according to a first reference example . FIG. 2 is a plan view showing the entire metal mask. FIG. 2 is a partial vertical cross-sectional side view of the metal mask. FIG. 2 is a partial plan view of a metal mask. FIG. 2 is a perspective view of a mask body and a frame body. FIG. 1 is an explanatory diagram showing the first stage of the manufacturing process of a metal mask. FIG. 10 is an explanatory diagram showing the latter stage of the manufacturing process of the metal mask. 1 is a vertical cross-sectional side view showing a main part of a metal mask according to a first embodiment of the present invention. FIG. 10 is a partial plan view showing a stress relaxation portion of a metal mask according to a second embodiment of the present invention. FIG. 10 is a partial plan view showing a stress relaxation portion of a metal mask according to a third embodiment of the present invention. FIG. 10 is a partial plan view showing a stress relaxation portion of a metal mask according to a second reference example . FIG. 11 is a vertical cross-sectional side view showing a main part of a metal mask according to a third reference example . FIG. 2 is a perspective view of a mask body and a frame body. FIG. 10 is a vertical cross-sectional side view showing a metal mask according to a fourth reference example .

1 to 7 show a first embodiment in which a metal mask according to the present invention is applied to a deposition mask used in the manufacture of an organic EL display. In this embodiment , the upper side of FIG. 1 is defined as the upper (front) surface of the deposition mask, and the lower side is defined as the lower (rear) surface of the deposition mask. Dimensions such as thickness and width in each figure are shown schematically and do not represent actual conditions. This also applies to FIGS. 8 to 14 , which show other embodiments and embodiments . In FIG. 2 , the deposition mask (metal mask) 1 includes a plurality of mask bodies 2 (four in this embodiment ) arranged in a matrix, a frame 3 surrounding each mask body 2 and supporting the mask bodies 2, and a metal layer 4 bonding the mask bodies 2 and 3 together in an inseparable manner.

As shown in Figure 5, the frame 3 is made of a material with a low coefficient of linear thermal expansion, such as Invar, Super Invar, or ceramic, and is formed into a lattice frame with the same number of mask openings 5 as the mask bodies 2. Each mask opening 5 is formed into a rectangular shape with rounded corners, and one mask body 2 is placed in each mask opening 5. The frame 3 also serves as a reinforcing material for the deposition mask 1, supporting the deposition mask 1 while reinforcing the mask bodies 2.

The mask body 2 is made of a thin metal plate formed by electroforming (plating) using electrodeposited metal made from nickel, copper, nickel alloys such as nickel-cobalt, or iron alloys such as iron-nickel. As shown in Figures 2 and 5, the mask body 2 is formed in a rectangular shape slightly smaller than the mask opening 5 with rounded corners. The mask body 2 has a pattern formation region 9 inside which a vapor deposition pattern made up of numerous independent vapor deposition through-holes 8 is formed, and an outer periphery region 10 surrounding the pattern formation region 9 on all four sides. The outer periphery region 10 has an outer periphery outer portion 11 on the outer edge side to which the metal layer 4 is bonded, and an inner periphery portion 12 between the outer periphery outer portion 11 and the pattern formation region 9. The outer shape of the mask body 2 and the opening shape of the mask opening 5 are configured to be similar.

The metal layer 4 is formed by electroforming (plating) using an electrodeposited metal made of nickel, copper, a nickel alloy such as nickel-cobalt, or an iron alloy such as iron-nickel, and includes a covering portion 16 that covers the upper surface edge portion of the frame 3 and the inner circumferential surface 15 of the mask opening 5, and an extending portion 17 that extends inward from the inner circumferential surface 15 of the mask opening 5 toward the center of the opening via the covering portion 16. The extending portion 17 is formed in a rectangular frame shape and includes a joining portion 18 at the tip side of the extending portion to which the outer circumferential portion 11 is joined, and a support portion 19 between the joining portion 18 and the inner circumferential surface 15 of the mask opening 5. In this reference example , the metal layer 4 is divided at the upper surface of the frame 3, and the upper surface of the frame 3 is exposed to the outer surface of the vapor deposition mask 1. By dividing the metal layer 4 on the top surface of the frame body 3, the metal layers 4 supporting each mask body 2 can be formed individually. Therefore, compared to a form in which the entire metal layer 4 is formed integrally, the internal stress generated in the metal layer 4 can be alleviated, and therefore expansion and contraction of the metal layer 4 after electroforming can be suppressed.

The mask body 2 and metal layer 4 are joined together with the outer peripheral portion 11 and the joint portion 18 overlapping each other, and the overlapping portion of the two (outer peripheral portion 11, joint portion 18) constitutes the joint region 20. The outer peripheral portion 11 and the joint portion 18 in the joint region 20 are formed in a flat plate shape, with the upper surface of the outer peripheral portion 11 and the lower surface of the joint portion 18 closely contacting each other. In addition, the extension portion 17 is provided with a circumferential joint rib 21 that protrudes downward from the underside of the support portion 19, and the inner surface of the joint rib 21 closely contacts the peripheral edge surface of the mask body 2.

As described above, the mask body 2 and the metal layer 4 are formed by electroforming, and therefore, slight expansion and contraction of the mask body 2 and the metal layer 4 is unavoidable when the temperature drops after electroforming. To prevent deformation of the mask body 2 and the metal layer 4 due to this expansion and contraction, the deposition mask 1 is provided with an easily expandable portion 24 between the pattern formation region 9 and the inner circumferential surface 15 of the mask opening 5. In the deposition mask 1 of this reference example , the easily expandable portion 24 is formed in a circumferential shape on the outer circumferential inner portion 12 of the outer circumferential region 10.

As shown in FIG. 4 , the easily stretchable portion 24 is formed by a large number of regularly arranged independent through-holes 25. Each through-hole 25 is a hole that penetrates the mask body 2, which is formed in a diamond (rectangular) shape in a plan view, from top to bottom (front to back). By regularly arranging a group of through-holes 25, the outer peripheral inner portion 12 of the easily stretchable portion 24 is formed in a mesh-like shape. The outer edge of the through-holes 25 that form the easily stretchable portion 24 is arranged up to the boundary between the outer peripheral inner portion 12 and the outer peripheral outer portion 11, while the inner edge of the through-holes 25 that form the easily stretchable portion 24 is arranged with a gap between them and the pattern formation region 9. As a result, the easily stretchable portion 24 is formed in the outer peripheral inner portion 12 so as to be biased toward the outer peripheral outer portion 11 (metal layer 4) side. The mask body 2, which is formed in a mesh-like shape in the easily stretchable portion 24, has spring properties, and expansion and contraction of the mask body 2 and the metal layer 4 is absorbed by the elastic deformation of the mask body 2 between adjacent through-holes 25, thereby eliminating deformation of the mask body 2. The pattern formation region 9 and the easy-to-stretch portions 24 are preferably configured to satisfy the relationship: (total opening area of vapor deposition through holes 8 formed in the pattern formation region 9) > (total opening area of through holes 25 forming the easy-to-stretch portions 24). Also, it is preferable to configure them to satisfy the relationship: (opening area of each vapor deposition through hole 8) > (opening area of each through hole 25).

Each through-hole 25 of the easily stretchable section 24 is filled with a filler 26. The filler 26 is made of a material with a lower modulus of elasticity than the material that makes up the easily stretchable section 24, i.e., the mask body 2, and is made of a resin material with a modulus of elasticity that is sufficiently lower than that of the nickel-based mask body 2. The top and bottom surfaces of the filler 26 filling each through-hole 25 and the mask body 2 are flush with each other. Note that, because the filler 26 is made of a material with a lower modulus of elasticity than the mask body 2, it does not prevent the easily stretchable section 24 from absorbing the expansion and contraction of the mask body 2 and metal layer 4.

An example of a manufacturing method of the vapor deposition mask 1 according to this reference example is shown in FIGS. 6 and 7. First, as shown in FIG. 6( a), a negative photoresist layer 31 is formed on the surface of an electroforming mold 30 made of, for example, stainless steel or brass, which has conductivity. Next, a pattern film 32 made of a glass mask is adhered to the photoresist layer 31. This results in a patterning precursor 33. The pattern film 32 has formed therein light-transmitting holes corresponding to the vapor deposition through-holes 8 of the mask body 2, the through-holes 25 constituting the easily expandable portions 24, and the joining ribs 21.

Next, the interior of the ultraviolet irradiation device, equipped with ultraviolet lamps 35, is preheated to the furnace temperature during exposure. Once preheating is complete, the resulting patterning pre-stage 33 is placed in the ultraviolet irradiation device's furnace. After the patterning pre-stage 33 has acclimatized to the furnace temperature, it is irradiated with ultraviolet light from the ultraviolet lamps 35, exposing the photoresist layer 31 through the pattern film 32. After removing the exposed patterning pre-stage 33, the pattern film 32 is removed from the photoresist layer 31, and the photoresist layer 31 is developed (unexposed portions are dissolved and removed), forming a primary pattern resist 36 on the electroforming matrix 30, as shown in Figure 6(b). The primary pattern resist 36 is composed of resist bodies 37 that correspond to each light-transmitting hole in the pattern film 32.

Next, the electroforming mold 30 on which the primary pattern resist 36 has been formed is placed in an electroforming tank prepared under specified conditions, and the surface of the electroforming mold 30 not covered by the resist body 37 is subjected to electroforming processing to form a primary electroforming layer 38 within the height range of the resist body 37, as shown in Figure 6(c). The primary electroforming layer 38 constitutes multiple mask bodies 2 that make up the completed vapor deposition mask 1, and a frame support 39 that is removed prior to completion. After the primary electroforming layer 38 is formed, the primary pattern resist 36 is dissolved and removed, as shown in Figure 6(d). This reveals the mask bodies 2 and frame support 39 with vapor deposition through-holes 8 and through-holes 25 formed therein. Note that the frame support 39 may be omitted.

In the next step, the frame 3 is bonded to the mask body 2 of the primary electroforming layer 38 with the metal layer 4. Specifically, as shown in Figure 7(a), a negative photoresist layer 42 is first formed over the entire surface of the primary electroforming layer 38, and then a pattern film 43 is adhered to the top of it. This pattern film 43 has rectangular light-transmitting holes with rounded corners that correspond to the pattern formation area 9 and inner peripheral portion 12 of the mask body 2.

Next, ultraviolet light is applied from an ultraviolet lamp 44 to expose the photoresist layer 42 through the pattern film 43. After exposure, the pattern film 43 is removed from the photoresist layer 42, and the photoresist layer 42 is developed (unexposed portions are dissolved and removed) to form the secondary pattern resist 45 shown in FIG. 7(b). The secondary pattern resist 45 is composed of a resist body 46 that covers the pattern formation region 9 and the surface of the inner peripheral portion 12 of the mask body 2. Because the vapor deposition through holes 8 and through holes 25 in the pattern formation region 9 are covered with the secondary pattern resist 45, electroforming liquid will not penetrate into the vapor deposition through holes 8 and through holes 25 during the subsequent electroforming process.

Next, as shown in FIG. 7( c), the frame 3 is placed at a predetermined position on the upper surface of the frame support portion 39 of the primary electroforming layer 38. In plan view, the frame support portion 39 is formed to be slightly larger than the frame 3. An adhesive layer 48 is pre-layered on the underside of the frame 3 supported by the frame support portion 39 via a release layer 47. This adhesive layer 48 fixes the frame 3 to the frame support portion 39 and prevents it from moving. A coating layer 49 is also laminated on the upper surface of the frame 3, preventing the formation of a metal layer 4 on the upper surface of the frame 3. In this example , the release layer 47 is formed of nickel (metal material), and the adhesive layer 48 is formed of an unexposed photoresist layer (resin layer). The coating layer 49 is formed of an exposed photoresist layer (resin layer).

Next, the electroforming mold 30 with the frame 3 placed on the primary electroforming layer 38 is placed in an electroforming tank prepared under specified conditions, and electroforming is performed on the surfaces of the electroforming mold 30, primary electroforming layer 38, and frame 3 that are not covered by the resist body 46 and coating layer 49. This forms a continuous secondary electroforming layer, i.e., metal layer 4, extending from the surface of the frame 3 to the mask body 2, as shown in Figure 7(d). The metal layer 4 on the surface of the primary electroforming layer 38 is formed within the height range of the secondary pattern resist 45. After the electroforming process, the primary electroforming layer 38 and metal layer 4 are peeled off from the electroforming mold 30. Next, the frame support portion 39 of the primary electroforming layer 38, together with the adhesive layer 48 and peeling layer 47, is peeled off from the frame 3 and metal layer 4, and the secondary pattern resist 45 and coating layer 49 are removed to obtain the deposition mask 1 shown in Figure 7(e). Finally, the through-holes 25 of the easily stretchable sections 24 are filled with resin fillers 26 to obtain the finished vapor deposition mask 1.

In the above manufacturing process, prior to forming the photoresist layer 42 on the primary electroforming layer 38, an adhesion plating layer can be formed on the primary electroforming layer 38 corresponding to the outer peripheral portion 11 to increase the bonding strength (adhesion) of the metal layer 4 to the mask body 2. The secondary pattern resist 45 can be removed before peeling off the primary electroforming layer 38 and metal layer 4, or before peeling off the frame support portion 39, adhesive layer 48, and release layer 47.

As described above, in the deposition mask 1 of this reference example , the easily stretchable portion 24 is provided in the outer circumferential inner portion 12 between the pattern formation region 9 and the inner circumferential surface 15 of the mask opening 5. Therefore, the easily stretchable portion 24 expands and contracts to absorb expansion and contraction of the mask body 2 due to internal stress during electroforming, thereby suppressing distortion of the mask body 2 (deposition mask 1) due to expansion and contraction of the mask body 2. Furthermore, the easily stretchable portion 24 provided in the outer circumferential inner portion 12 outside the pattern formation region 9 can prevent expansion and contraction deformation of the easily stretchable portion 24 from affecting the pattern formation region 9, thereby suppressing distortion of the mask body 2 in the pattern formation region 9, where greater flatness is required. As described above, according to this reference example , distortion of the mask body 2 can be suppressed, and therefore a deposition mask 1 including a mask body 2 with excellent flatness can be obtained.

In a vapor deposition mask 1 in which the mask body 2 and frame 3 are inseparably joined via the metal layer 4, the easily stretchable portion 24 is provided on the inner peripheral portion 12 of the mask body 2. This allows the easily stretchable portion 24 to absorb expansion and contraction of the mask body 2 and metal layer 4 due to internal stress during electroforming, thereby preventing distortion of the mask body 2 caused by expansion and contraction of the mask body 2 and metal layer 4. Furthermore, the easily stretchable portion 24 is provided in a circumferential manner, allowing the easily stretchable portion 24 to absorb expansion and contraction of the entire periphery of the mask body 2 in a plan view, further preventing distortion of the mask body 2.

The easily stretchable sections 24 are formed from a large number of independent through-holes 25 that penetrate the mask body 2 from front to back. This allows the outer circumferential inner portion 12 (mask body 2) where the easily stretchable sections 24 are provided to be configured in a mesh-like structure, giving it springiness, which reliably absorbs the expansion and contraction of the mask body 2 and metal layer 4. Another advantage is that the easily stretchable sections 24 can be made to exhibit a variety of springiness by changing the diameter and number of the through-holes 25 that form the easily stretchable sections 24.

Since the easily stretchable portion 24 is provided in the outer circumferential inner portion 12, the easily stretchable portion 24 can be provided using a simple manufacturing method that simply involves forming the through-holes 25 in the outer circumferential inner portion 12 at the same time as electroforming the mask body 2.

By positioning the easily stretchable portion 24 biased toward the metal layer 4, it is possible to prevent the expansion and contraction deformation of the easily stretchable portion 24 from affecting the pattern formation region 9, thereby further improving the flatness of the mask body 2 in the pattern formation region 9.

The through-holes 25 are filled with a filler 26 made of a material with a lower elastic modulus than the material constituting the portion forming the easily expandable section 24. This prevents the vapor deposition material used in the vapor deposition mask method from passing through the vapor deposition mask 1 via the through-holes 25, preventing the vapor deposition material from being deposited in unnecessary areas.

For these reasons, the deposition mask according to this reference example can contribute to Goal 9 (Industry, innovation and infrastructure: Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation) and Goal 12 (Responsible consumption and production: Ensure sustainable consumption and production patterns) of the Sustainable Development Goals (SDGs) advocated by the United Nations.

( First Embodiment) Figure 8 shows a first embodiment of a metal mask according to the present invention. This embodiment differs from the first reference example in that an easily stretchable portion 24 is formed in the metal layer 4. Otherwise, this embodiment is the same as the first reference example . Therefore, the same configurations, structures, and components are denoted by the same reference numerals, and their description will be omitted. This also applies to the following embodiments and reference examples . As shown in Figure 8, the easily stretchable portion 24, which is formed by a large number of independent through holes 25, is formed in a circumferential shape on the support portion 19 of the metal layer 4. In this embodiment, the expansion and contraction of the mask body 2 and the metal layer 4 is absorbed by the elastic deformation of the metal layer 4 between adjacent through holes 25, thereby eliminating deformation of the mask body 2.

The manufacturing method of the vapor deposition mask 1 according to this embodiment differs from that of the first reference example in the pattern films 32 and 43 used when exposing the photoresist layers 31 and 42. The pattern film 32 has light-transmitting holes formed therein that correspond to the vapor deposition through-holes 8 and the joining ribs 21 of the mask body 2, and a primary electroformed layer 38 formed by electroforming is composed of the mask body 2 in which the vapor deposition through-holes 8 are formed and a frame support portion 39. The pattern film 43 has light-transmitting holes formed therein that correspond to the pattern formation region 9, the outer circumferential inner portion 12, and the through-holes 25 of the mask body 2, and a metal layer 4 formed by electroforming has the through-holes 25 in the support portion 19.

As described above, even when the easily expandable portion 24 is provided in the support portion 19, the easily expandable portion 24 can be provided using a simple manufacturing method that simply involves forming the through-holes 25 at the same time as electroforming the metal layer 4.

( Second embodiment) Fig. 9 shows a second embodiment of the metal mask according to the present invention. This embodiment is a different embodiment of the through holes 25 that form the easy-to-expand portions 24. As shown in Fig. 9, each through hole 25 is formed in a regular hexagonal shape (polygonal shape) in plan view, and by regularly arranging the through holes 25, the outer circumferential inner portion 12 of the easy-to-expand portions 24 is formed in a honeycomb structure.

( Third embodiment) Figure 10 shows a third embodiment of the metal mask according to the present invention. This embodiment is yet another embodiment of the through holes 25 that form the easy-to-stretch portions 24. As shown in Figure 10, each through hole 25 is formed in a perfect circular shape (circular shape) in plan view, and by regularly arranging the through holes 25, the outer circumferential inner portion 12 of the easy-to-stretch portions 24 is formed in a punched metal shape. Note that the through holes 25 can also be formed in an elliptical shape.

( Second Reference Example ) FIG. 11 shows a second reference example of a metal mask. In this reference example , the easily stretchable portion 24 is formed by a circumferential groove 51 recessed in the thickness direction of the mask body 2 instead of the through-holes 25. As shown in FIG. 11 , the grooves 51 are formed on the upper and lower surfaces of the mask body 2. In this reference example , four grooves 51 are formed alternately on the upper and lower surfaces of the outer circumferential inner portion 12. The mask body 2 in the groove 51 area (the mask body 2 forming the bottom of the groove 51) is more flexible than other portions. The expansion and contraction of the mask body 2 and the metal layer 4 is absorbed by the flexural deformation of the mask body 2 in the groove 51 area, thereby eliminating deformation of the mask body 2. The number of grooves formed in the outer circumferential inner portion 12 (mask body 2) as the easily stretchable portion 24 can be more or less than four. The easily stretchable portion 24 may be formed with a larger number of grooves 51 to form the easily stretchable portion 24 in a bellows-like shape. Alternatively, the grooves 51 may be replaced by a large number of independent blind holes (recesses).

In addition to the above, the mask body 2 can also be formed by etching or laser processing a thin plate made of a metal material such as the materials mentioned in the above embodiments or Invar. Since internal stress is generated in the mask body 2 during etching or laser processing, even in mask bodies 2 formed using this type of method, the easily stretchable portion 24 can absorb the expansion and contraction of the mask body 2, thereby preventing distortion in the pattern formation region 9.

In the above embodiments, the through-holes 25 (easily stretchable portions 24) were formed simultaneously when the mask body 2 or metal layer 4 was formed. However, the through-holes 25 (easily stretchable portions 24) can also be formed after the mask body 2 or metal layer 4 is formed, or by etching or lasering the thin metal plate. In this case, the easily stretchable portions 24 can be easily provided in the desired area, and the spring properties can also be increased by additionally machining the through-holes 25 into the existing easily stretchable portions 24. The easily stretchable portions 24 can be provided in the bonding area 20, and in this case the through-holes 25 are also formed by etching or lasering so as to penetrate the mask body 2 and metal layer 4.

Furthermore, the form, shape, and formation region of the easily stretchable portion 24 are not limited to those of the above embodiments. For example, the easily stretchable portion 24 can be provided intermittently in the peripheral region 10 and/or metal layer 4 along each side of the pattern formation region 9. Furthermore, the easily stretchable portion 24 may be provided in some locations and not in others (intermittently) in the peripheral region 10 and/or metal layer 4 along each side of the pattern formation region 9. Furthermore, if locations or regions where internal stress will concentrate can be predicted through simulations using an analytical device, measures can be taken such as proactively providing easily stretchable portions 24 in those locations or regions, or increasing the spring properties of those locations or regions.

The filler 26 may be made of a material with a lower modulus of elasticity than the material constituting the mask body 2, and may be made of a metal or ceramic material. It is preferable that the filler 26 be made of a material with a coefficient of linear thermal expansion that is the same as or lower than the material constituting the mask body 2. The filler 26 may be omitted. In this case, it is preferable to make the diameter of the through-hole 25 sufficiently small to prevent the vapor deposition material from passing through the through-hole 25.

The mask body 2 and metal layer 4 are joined by forming the outer peripheral portion 11 and the joint portion 18 into a flat plate shape. However, the mask body 2 and metal layer 4 can also be joined by opening multiple independent connecting holes in the outer peripheral portion 11 of the mask body 2 and inserting the joint portion 18 into the connecting holes. In this case, the two (mask body 2, metal layer 4) can be joined more firmly. The metal layer 4 may also have a configuration in which the covering portion 16 covers the upper surface of the frame body 3.

12 and 13 show a metal mask according to a third reference example . As shown in FIG. 13 , a vapor deposition mask 1 according to this reference example is made of a thin metal plate and includes a mask body 2 in which pattern formation regions 9 are arranged in a matrix, and a frame 3 that supports the mask body 2 in which mask openings 5 are formed so as to surround the pattern formation regions 9. Four pattern formation regions 9 are provided in the mask body 2, and a lattice-frame-shaped outer peripheral region 10 is provided so as to surround all four peripheries of the pattern formation regions 9. The outer peripheral region 10 includes an inner peripheral portion 12 that surrounds the outside of the pattern formation regions 9 and an outer peripheral portion 11 that surrounds the inner peripheral portion 12, and the outer peripheral portion 11 is formed in a lattice-frame shape.

The outer shape of the mask body 2 is formed to be the same as the outer shape of the frame 3, and the frame 3 is inseparably bonded to the outer peripheral portion 11 of the mask body 2 with an adhesive, with the outer edges of both (mask body 2, frame 3) coinciding. A large number of independent through-holes 25 are formed circumferentially in the inner peripheral portion 12 between the pattern formation region 9 and the inner peripheral surface 15 of the mask opening 5, providing an easily stretchable portion 24.

14 shows a fourth reference example of a metal mask. This reference example differs from the third reference example in that the outer shape of the mask body 2 is formed to be slightly smaller than the outer shape of the frame body 3. In this way, the outer shape of the mask body 2 does not need to match the outer shape of the frame body 3; conversely, the outer shape of the mask body 2 can be formed to be slightly larger than the outer shape of the frame body 3.

As described above, even in a deposition mask in which the mask body 2 and frame body 3 are inseparably bonded together with an adhesive, the stretchable section 24 can expand and contract to absorb the expansion and contraction of the mask body 2 caused by internal stress during electroforming, thereby preventing distortion of the mask body 2.

1. Metal mask (evaporation mask)
2 Mask body 3 Frame 4 Metal layer 5 Mask opening 8 Through hole (evaporation through hole)
9 Pattern formation region 10 Outer peripheral region 11 Outer peripheral outer portion 12 Inner peripheral portion 15 Inner peripheral surface of mask opening 18 Bonding portion 19 Support portion 24 Easy-to-expand portion 25 Through hole 26 Filler

Claims (5)

a mask body (2) made of a thin metal plate and having a pattern forming region (9) in which a large number of independent through holes (8) are arranged;
a frame (3) having a mask opening (5) and supporting the mask body (2) with a pattern forming region (9) facing the mask opening (5);
Equipped with
An easily stretchable portion (24) is provided between the pattern forming region (9) and the inner peripheral surface (15) of the mask opening (5),
The mask body (2) is formed smaller than the mask opening (5) and includes an inner pattern forming region (9) and an outer peripheral region (10) surrounding the pattern forming region (9);
The mask body (2) and the frame body (3) are inseparably joined via a metal layer (4) extending inward from the inner peripheral surface (15) of the mask opening (5) to the outer peripheral region (10),
A metal mask characterized in that an easily stretchable portion (24) is provided in a metal layer (4) . 2. The metal mask according to claim 1 , wherein the stretchable portion (24) is provided in a circumferential shape on the metal layer (4) . 3. The metal mask according to claim 2, wherein the easily stretchable portion (24) is formed of a large number of independent through holes (25) penetrating the metal layer (4) from the front to the back. The mask body (2) and the metal layer (4) are joined together with the outer peripheral region (10) and the metal layer (4) overlapping on the front and back,
The metal layer (4) includes a joint (18) overlapping the outer peripheral region (10) and a support (19) between the joint (18) and the inner peripheral surface (15) of the mask opening (5);
4. The metal mask according to claim 2, wherein the flexible portion (24) is provided on the support portion (19). 4. The metal mask according to claim 3 , wherein the through hole (25) is filled with a filler (26) made of a material having a lower elastic modulus than the material constituting the portion forming the easily stretchable portion (24) .