CN113802089A

CN113802089A - Metal mask plate

Info

Publication number: CN113802089A
Application number: CN202010534133.2A
Authority: CN
Inventors: 王广成; 樊春雷; 郑庆靓; 刘通
Original assignee: EverDisplay Optronics Shanghai Co Ltd
Current assignee: EverDisplay Optronics Shanghai Co Ltd
Priority date: 2020-06-12
Filing date: 2020-06-12
Publication date: 2021-12-17

Abstract

The application provides a metal mask plate, include: the mask comprises a mask body and a plurality of evaporation holes formed in the mask body; the mask plate body is provided with a glass surface and an evaporation surface which are arranged oppositely, each evaporation hole comprises a first groove and a second groove, the first grooves and the second grooves are arranged along the thickness direction of the mask plate body and are communicated with each other, one end of each first groove is flush with the glass surface, the other end of each first groove is connected with one end of each second groove, and the other end of each second groove is flush with the evaporation surface; wherein, the lateral wall of first recess and the contained angle of glass face is below 90. In the metal mask plate that this application provided, evaporate the trompil shape of hole at the glass face through the adjustment, avoid the inner wall of coating by vaporization mouth to shelter from organic material, and then enlarge the effective membrane width of coating by vaporization, avoid the edge of pixel shadow region to appear simultaneously for the tolerance range of the coating by vaporization position of effective light zone is bigger in the pixel, and then improves the yield of coating by vaporization.

Description

Metal mask plate

Technical Field

The application relates to the technical field of display, in particular to a metal mask plate.

Background

In the OLED manufacturing technology, a mask plate for vacuum evaporation is a crucial component, and the mask plate can control the position of organic material deposited on a screen body, so that different organic patterns are formed on the screen body. The Mask mainly comprises a universal Metal Mask (CMM for short) and a precision Metal Mask (FMM for short), wherein the universal Metal Mask is mainly used for evaporating a Common layer, and the precision Metal Mask is also called a high-precision Metal Mask and is mainly used for evaporating a luminescent layer.

Before vapor deposition, a mask plate pull net needs to be fixed on a mask frame, and the mask plate has certain tension after the pull net is fixed. In vapor deposition, the mask plate is fixed to the substrate, the surface to be vapor-deposited of the substrate faces the vapor deposition source, and vapor deposition particles (film forming material) from the vapor deposition source are vapor-deposited on the surface to be vapor-deposited through the openings of the mask plate.

In the actual evaporation process, the problems of local point position deviation or color deficiency of individual point positions exist in the evaporation of the luminous layer due to the fact that the process parameters of the precise metal mask plate and the range of the stretching precision are too wide. The existing precise metal mask plate is adopted for carrying out evaporation coating on the luminous layer, and the evaporation coating yield is low.

Disclosure of Invention

In view of the above, the present application provides a metal mask plate to solve the problem in the prior art that the evaporation yield is affected due to local dot shift or color deficiency of individual dots in the evaporation of the light-emitting layer.

In order to solve the technical problem, the invention provides a metal mask plate, which comprises: the mask plate comprises a mask plate body and a plurality of evaporation holes formed in the mask plate body;

the mask plate body is provided with a glass surface and an evaporation surface which are oppositely arranged, and the plurality of evaporation holes are arranged in an array mode and penetrate through the glass surface and the evaporation surface;

each evaporation hole comprises a first groove and a second groove, the first groove and the second groove are arranged along the thickness direction of the mask plate body and are communicated with each other, one end of the first groove is flush with the glass surface, the other end of the first groove is connected with one end of the second groove, and the other end of the second groove is flush with the evaporation surface;

wherein, the lateral wall of first recess and the contained angle of glass face is below 90.

Optionally, in the metal mask, the depth of the first groove is less than 5 μm.

Optionally, in the metal mask, the depth of the first groove is less than 3 μm.

Optionally, in the metal mask, a thickness of the mask body ranges from 15 μm to 30 μm.

Optionally, in the metal mask plate, the cross sections of the first groove and the second groove of the evaporation hole are both of an axisymmetric structure, and the symmetry axis of the axisymmetric structure coincides with the central axis of the evaporation hole.

Optionally, in the metal mask plate, the first groove and the second groove are both formed by an etching forming process.

Optionally, in the metal mask plate, an included angle between the side wall of the first groove and the glass surface is in a range of 60 ° to 90 °.

Optionally, in the metal mask plate, the cross section of the second groove is a curve, and an included angle between the side wall of the second groove and the evaporation surface is more than 90 °.

Optionally, in the metal mask plate, an included angle between a connecting line at two ends of the curve and a plane where the evaporation surface is located is an evaporation angle, and the evaporation angle is less than 55 °.

Optionally, in the metal mask plate, an opening size of the evaporation hole on the glass surface is smaller than an opening size of the evaporation hole on the evaporation surface.

In the metal mask plate provided by the invention, the shape of the opening of the evaporation hole on the glass surface is adjusted, so that the inner wall of the evaporation opening is prevented from shielding organic materials, the effective film width of evaporation is further enlarged, meanwhile, the shadow area is prevented from appearing at the edge of a pixel, the tolerance range of the evaporation position of an effective light emitting area in the pixel is larger, and the yield of evaporation is further improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 shows a schematic structural diagram of a metal mask plate according to a first embodiment of the present invention;

FIG. 2 shows a top view of a pixel evaporated by a metal mask of the prior art;

fig. 3 is a top view illustrating a pixel evaporated by a metal mask according to a first embodiment of the present invention;

fig. 4 shows a schematic structural diagram of a metal mask plate according to a second embodiment of the present invention;

fig. 5 is a top view illustrating a pixel evaporated by a metal mask according to a second embodiment of the present invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repetitive description will be omitted.

[ EXAMPLES one ]

Please refer to fig. 1, which is a schematic structural diagram of a metal mask according to a first embodiment of the present invention. As shown in fig. 1, the metal mask 10 includes: the mask comprises a mask body and a plurality of evaporation holes 13 formed in the mask body; the mask plate body is provided with a glass surface 11 and an evaporation surface 12 which are oppositely arranged, and the plurality of evaporation holes 13 of the mask plate body are arranged in an array mode and penetrate through the glass surface 11 and the evaporation surface 12; each evaporation hole 13 comprises a first groove 131 and a second groove 132, the first groove 131 and the second groove 132 are arranged along the thickness direction of the mask plate body and are communicated with each other, one end of the first groove 131 is flush with the glass surface 11, the other end of the first groove 131 is connected with one end of the second groove 132, and the other end of the second groove 131 is flush with the evaporation surface 12; the included angle between the side wall of the first groove 131 and the glass surface 11 is below 90 degrees.

Specifically, the mask plate body is provided with a glass surface 11 and an evaporation surface 12 which are oppositely arranged, the glass surface 11 is also called a small opening surface, the small opening surface faces away from the evaporation source and faces the glass substrate, and the evaporation surface 12 is also called a large opening surface, and faces the evaporation source. The size of the opening of the evaporation hole 13 on the glass surface 11 is generally smaller than the size of the opening of the evaporation hole 13 on the evaporation surface 12.

In this embodiment, the metal mask plate 10 is a high-precision metal mask plate (FMM), the metal mask plate 10 may be made of stainless steel, invar alloy, pure nickel or nickel alloy material, and the metal mask plate made of stainless steel, invar alloy, pure nickel or nickel alloy material may ensure that the metal mask plate has good strength and hardness, so that the metal mask plate may be better applied to the evaporation operation; moreover, the metal mask plate has certain magnetism, and can be adsorbed by magnetic adsorption equipment at the back of the glass substrate in the later application process, so that the drooping amount of the metal mask plate is further reduced; meanwhile, the stainless steel, the invar alloy, the pure nickel or the nickel alloy material has low price, is convenient for mass production, saves the production cost and improves the production efficiency. Preferably, the metal mask plate 10 is made of Invar (Invar) having a small thermal expansion coefficient. Therefore, the metal mask plate has better stability in the vapor deposition process.

As shown in fig. 1, a plurality of evaporation holes 13 are formed in the mask plate body, the plurality of evaporation holes 13 penetrate through the mask plate main body 10, each evaporation hole 13 includes a first groove 131 and a second groove 132, the first groove 131 and the second groove 132 are arranged along the thickness direction of the mask plate body and are communicated with each other, the side wall of the first groove 131 is connected with the glass surface 11, the side wall of the second groove 132 is connected with the evaporation surface 12, H is the thickness of the mask plate body, H is the depth of the first groove 131, α is the included angle between the side wall of the first groove 131 and the glass surface 11, and β is the included angle between the side wall of the second groove 132 and the evaporation surface 12.

In this embodiment, the evaporation holes 13 are rectangular rounded corners. It should be noted that the shape of the evaporation hole 13 is merely an example and is not limited, and those skilled in the art can set the shape of the evaporation hole 13 according to actual needs. For example, the shape of the evaporation hole 13 may be a diamond-shaped rounded corner, a rectangle, a square, an octagon, or other shapes.

In this embodiment, an included angle β between the sidewall of the second groove 132 and the evaporation surface 12 is required to be greater than 90 °. Preferably, the side wall of the second groove 132 forms an angle with the evaporation surface 12 in the range of 90 ° to 120 °.

In this embodiment, the thickness H of the mask body is between 15 μm and 30 μm. Therefore, the structural strength of the metal mask plate can be ensured, the problem that the screen cannot be stretched or the service life is short due to too thin thickness is avoided, and the requirement of a plating Angle (Taper Angle) can be met.

As shown in fig. 1, the cross section of the second groove 132 is a curve, an included angle between a connecting line of two ends of the curve and the plane of the evaporation surface 12 is an evaporation angle θ, and the evaporation angle θ is required to be less than 55 °.

In this embodiment, the cross section of the first groove 131 is a straight line, that is, the sidewall of the first groove 131 is a plane.

In this embodiment, the first groove 131 and the second groove 132 are both formed by an etching process, and both cross sections thereof are axisymmetric structures, and the symmetry axes of the first groove 131 and the second groove 132 are coincident with the central axis of the evaporation hole 13. In the etching forming process, the shape of the opening of the metal mask plate 10 on the glass surface 11 is ensured by adjusting the parameters of the etching solution, so that the side wall of the first groove 131 is perpendicular to the glass surface 11, that is, the included angle α between the side wall of the first groove 131 and the glass surface 11 is 90.

In other embodiments, the included angle α between the sidewall of the first groove 131 and the glass surface 11 may be smaller than 90 °. Preferably, the side wall of the first groove 131 forms an angle with the glass surface 11 in the range of 60 ° to 90 °.

In this embodiment, since the included angle α between the sidewall of the first groove 131 and the glass surface 11 is less than or equal to 90 °, the effective area of the evaporation hole 13 opening on the glass surface 11 is the largest, and the inner wall of the evaporation hole does not shield the organic material. Therefore, the effective film width of evaporation is further enlarged, and the effective film width is the width of the film thickness of the evaporation coating film layer which is more than or equal to 95%.

Compare with current metal mask plate, the metal mask plate that this embodiment provided can guarantee that its effective area in 11 trompils of glass face is the biggest because the shape of evaporation coating hole 13 at glass face 11, consequently is to improving the big benefit of yield of coating by vaporization.

Please refer to fig. 2, which is a top view of a pixel evaporated by a metal mask in the prior art. As shown in fig. 2, in the existing metal mask plate, the effective area of the evaporation hole in the glass surface opening is limited by the shape of the opening, so that there is a Shadow region S at the edge of the pixel evaporated by the existing metal mask plate, and further the evaporation position of the effective light emitting region P is affected, because the evaporation position of the effective light emitting region is affected by the Shadow region, the allowable tolerance range of the evaporation position is small, the evaporation position of the effective light emitting region is slightly deviated, so that the color deficiency problem is likely to occur, the larger the Shadow region S is, the narrower the effective film width is, even the Shadow Effect (Shadow Effect) is generated in severe cases, and the evaporation yield and the product quality are reduced.

Please refer to fig. 3, which is a top view of a pixel evaporated by a metal mask according to an embodiment of the present invention. As shown in fig. 3, the shadow region does not exist at the edge of the pixel evaporated by using the metal mask provided by the embodiment of the present invention, so that the allowable tolerance range of the effective light emitting region P during evaporation is relatively larger, and under the same condition, the metal mask provided by the embodiment of the present invention has a lower risk of local point position deviation or color deficiency of individual point position during evaporation, and the evaporation yield is higher.

In this embodiment, the depth h of the first groove 131 is less than 5 μm. Preferably, the depth h of the first groove 131 is 3 μm or less. Further, the depth h of the first groove 131 is 2 μm or 3 μm. Compared with the existing metal mask plate, the opening depth of the evaporation hole on the glass surface (namely the depth h of the first groove 131) is smaller, so that even if a Shadow area appears after evaporation, the Shadow area is smaller, a Shadow Effect (Shadow Effect) can be avoided, and the evaporation yield and the product quality are improved.

[ example two ]

Please refer to fig. 4, which is a schematic structural diagram of a metal mask according to a second embodiment of the present invention. As shown in fig. 4, the metal mask 20 includes: a mask plate body and a plurality of evaporation holes 23 formed on the mask plate body; the mask plate body is provided with a glass surface 21 and an evaporation surface 22 which are oppositely arranged, and the plurality of evaporation holes 23 of the mask plate body are arranged in an array mode and penetrate through the glass surface 21 and the evaporation surface 22; each evaporation hole 23 comprises a first groove 231 and a second groove 232, the first groove 231 and the second groove 232 are arranged along the thickness direction of the mask plate body and are communicated with each other, one end of the first groove 231 is flush with the glass surface 21, the other end of the first groove 231 is connected with one end of the second groove 232, and the other end of the second groove 231 is flush with the evaporation surface 22; the side wall of the first groove 231 forms an angle of less than 90 ° with the glass surface 21.

Specifically, the mask plate body is provided with a glass surface 11 and an evaporation surface 12 which are arranged oppositely, and a plurality of evaporation holes 23 are formed in the mask plate body.

As shown in fig. 4, each evaporation hole 23 includes a first groove 231 and a second groove 232, the first groove 231 and the second groove 232 are all arranged along the thickness direction of the mask body and are communicated with each other, one end of the first groove 231 is flush with the glass surface 21, one end of the second groove 232 is flush with the evaporation surface 22, the side wall of the first groove 231 is connected with the glass surface 21, the side wall of the second groove 232 is connected with the evaporation surface 22, α is an included angle between the side wall of the first groove 231 and the glass surface 21, and β is an included angle between the side wall of the second groove 232 and the evaporation surface 22.

The difference between this embodiment and the first embodiment is that the cross section of the first groove 231 is a curve, not a straight line, i.e., the sidewall of the first groove 231 is a curved surface, not a plane.

In this embodiment, the first groove 231 and the second groove 232 are also formed by an etching process, and the cross sections of the first groove 231 and the second groove 232 are curved. In the etching forming process, the shape of the opening of the metal mask plate 20 on the glass surface is ensured by adjusting the parameters of the etching solution, so that the included angle α between the side wall of the first groove 231 and the glass surface 21 is smaller than 90.

Preferably, the side wall of the first groove 231 is included at an angle ranging from 60 ° to 90 ° with respect to the glass surface 21.

In this embodiment, since the included angle α between the sidewall of the first groove 231 and the glass surface 21 is less than or equal to 90 °, the effective area of the evaporation hole 23 opening on the glass surface 21 is the largest, and the inner wall of the evaporation hole does not shield the organic material. Therefore, the effective film width of evaporation is further enlarged, and the yield of evaporation is improved.

Please refer to fig. 5, which is a top view of a pixel evaporated by a metal mask according to a second embodiment of the present invention. As shown in fig. 5, the pixel edge of the metal mask plate evaporated by the embodiment of the present invention also has no shadow region, so that the allowable tolerance range of the effective light emitting region P during evaporation is relatively larger, and compared with the existing metal mask plate, the metal mask plate provided by the embodiment of the present invention has a lower risk of color shortage during evaporation.

The drawings are only schematic and show the metal mask plate provided by the invention. For clarity, the shapes of the elements and the number of the elements in the above-mentioned figures are simplified and some elements are omitted, so that those skilled in the art can make changes according to actual needs, and the changes are within the protection scope of the present invention and will not be described herein.

It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

In summary, the metal mask provided by the invention prevents the inner wall of the evaporation opening from shielding organic materials by adjusting the shape of the opening of the evaporation hole on the glass surface, so as to expand the effective film width of evaporation, and simultaneously prevents the edge of the pixel from generating a shadow region, so that the tolerance range of the evaporation position of the effective light emitting region in the pixel is larger, and the yield of evaporation is improved.

The foregoing is a more detailed description of the present application in connection with specific preferred embodiments and it is not intended that the present application be limited to these specific details. For those skilled in the art to which the present application pertains, several simple deductions or substitutions may be made without departing from the concept of the present application, and all should be considered as belonging to the protection scope of the present application.

Claims

1. A metal mask plate, comprising: the mask plate comprises a mask plate body and a plurality of evaporation holes formed in the mask plate body;

2. The metal mask of claim 1, wherein the depth of the first groove is below 5 μm.

3. A metal mask according to claim 2, wherein the depth of the first grooves is below 3 μm.

4. A metal mask according to claim 1, wherein the thickness of the mask body is in the range of 15 μm to 30 μm.

5. The metal mask according to claim 1, wherein the first groove and the second groove of the evaporation hole have axisymmetric cross-sections, and the symmetry axis of the axisymmetric structure coincides with the central axis of the evaporation hole.

6. The metal mask of claim 1, wherein the first and second grooves are both made by an etch forming process.

7. A metal mask according to claim 1, wherein the side wall of the first groove forms an angle with the glass surface in the range of 60 ° to 90 °.

8. The metal mask of claim 1, wherein the cross section of the second groove is a curve, and an included angle between the sidewall of the second groove and the deposition surface is above 90 °.

9. The metal mask according to claim 8, wherein an included angle between a connecting line of two ends of the curve and a plane where the evaporation surface is located is an evaporation angle, and the evaporation angle is less than 55 °.

10. The metal mask of claim 1 wherein the size of the opening of the evaporation hole on the glass surface is smaller than the size of the opening of the evaporation hole on the evaporation surface.