TWI749533B - Metal mask - Google Patents

Abstract

A metal mask is formed in a thin mask body with a low thermal expansion coefficient to form a plurality of coating pattern forming structures, a predetermined area of the mask body forms a slit pattern structure, and a plurality of opening slits of the slit pattern structure respectively include a first recess portion communicates with the slit pattern forming portion of the first laser cavity forming portion of cut shaped etch, oblique sidewalls of the first recess portion of the bevel angle range of ³⁵⁰ ~ ^850, a first The depth of the cavity is less than or equal to 4/5 times the thickness of the mask body, and the depth of the slit pattern forming part with vertical peripheral walls is greater than or equal to 1/5 times the thickness of the mask body, by first etching and then laser cutting The two-stage processing of the laser beam, combined with the depth size control of the first cavity part and the slit pattern forming part, makes it easy to control and produce high-resolution opening slit shapes, and shorten the laser beam in the cutting slit pattern forming part. The processing time effectively overcomes the deformation caused by the high temperature of laser cutting, and improves the product yield of the metal mask.

Description

Metal mask

The present invention relates to a metal mask, in particular to a common/open mask (CMM) used in the organic light-emitting diode (Organic Light-Emitting Diode, OLED) coating process to form a coating layer, And has a metal mask with a very fine slit pattern structure.

The under-screen camera technology of smart phones and various display screens has been gradually commercialized, and the goal of making smart phones and various display screens full-screen has been realized. Currently used in the field of under-screen camera technology in the field of organic light-emitting diode (OLED) display screen manufacturing, the coded aperture camera technology or the partial semi-transmissive display is an important technology known. However, when the OLED display screen is full-screen, it must take into account the consistency of the appearance of the OLED display screen when the front camera lens function is activated. At the same time, the front camera lens also needs to obtain sufficient luminous flux to achieve the lowest resolution. Coded image, therefore, a mask with extremely fine slit patterns is a solution for this under-screen photography coded image technology or optical imaging.

In order to achieve the purpose of full-screen display by encoding image technology in the field of photography under OLED screens, currently the vapor-deposited film layer in the OLED coating process is mainly used through the patterned cathode ultra-fine metal mask (Fine Metal Mask, FMM) Design to achieve, or add a specific slit pattern structure in the common metal mask (CMM), through the very fine slit pattern structure, with transparent and or non-transparent coating process to achieve the incident light Penetrate the area to image on the imaging system and re-decode.

Currently, the technology of using a patterned cathode fine metal mask (FMM) for the vapor-deposited film layer will shorten the service life of the patterned cathode and increase the manufacturing process, which has the disadvantages of increased manufacturing cost and decreased productivity. As for the existing common metal mask (CMM), when the fine slit pattern structure is formed, it is generally manufactured in a thin metal plate by means of yellow light lithography etching. As shown in FIG. 7, it is in a thin metal plate 30. The opening slit 31 formed by the first cavity 311 and the second cavity 312 connected by yellow light lithography on both sides is formed, and the first cavity 311 The connection part with the second cavity 312 serves as a coating forming part. Although the yellow light lithography etching technique can achieve considerable precision in the prior art, but in terms of the extremely fine scale and shape requirements of the slit pattern structure, the yellow light lithography etching method makes the slit pattern in the thin metal plate The structure is not easy to achieve a specific sharp-angled opening slit shape with high resolution, and the quality control is difficult, and there is a problem of low product yield.

Furthermore, the laser cutting method is also an existing technology that can cut the thin metal sheet to form a slit pattern structure with fine size and shape. However, the laser cutting method uses high-energy laser light to cut the slits on the thin metal sheet. In the pattern structure, the cutting time of the high-energy laser light projected on the thin metal plate is prolonged and the deformation is caused by the high temperature. Therefore, it is still difficult to achieve the specific sharp corner with high resolution when making the slit pattern structure. The shape of the opening is slit, and there is a problem of low product yield.

The purpose of the present invention is to provide a metal mask to solve the problem that the mask used in the existing OLED display screen coating process is difficult to control the accuracy of the shape and size of the slit opening corresponding to the extremely fine slit pattern.

In order to achieve the foregoing objective, the metal mask proposed by the present invention includes: a mask body with a low coefficient of thermal expansion, the thickness of which is 15 μm to 150 μm, and the two opposite sides in the thickness direction of the mask body are a first side surface and a first side surface. A second side surface defining a reference plane parallel to the first side surface and the second side surface; a plurality of coating pattern forming structures are formed in the mask body, and each of the coating pattern forming structures includes A pattern forming hole which penetrates from the first side to the second side of the mask body; and a slit pattern structure formed in a predetermined area of the mask body, the slit pattern structure It includes a plurality of opening slits that penetrate from the first side surface to the second side surface of the mask body, and the opening slits include a first cavity portion formed by etching and a portion formed by laser cutting. A slit pattern forming part, the first recess part is an oblique recess whose size decreases from the first side surface of the mask body to the second side surface, and the reference slope of the oblique side wall around the first recess part an oblique angle relative to the reference plane of the angular interval in the range of ³⁵⁰ - ^850, the depth dimension of the pocket portion of the system of the first range is greater than 0 and less than or equal to 4/5 times the thickness of the mask body, the slots The slit pattern forming portion extends from the small-diameter end of the first cavity portion toward the second side surface, and the side wall of the mask body is perpendicular to the reference plane, and the depth dimension range of the slit pattern forming portion is smaller than that of the mask. The thickness of the film body is greater than or equal to 1/5 times the thickness of the mask body.

The aforementioned metal mask construction invention is applied to a common metal mask (CMM) used in the coating process of an OLED display screen with under-screen photography, using a thin mask body for each slit pattern structure in a predetermined area An opening slit includes a first cavity portion formed by etching and a pattern forming portion formed by laser cutting, and the depth size range of the first cavity portion is set to be greater than 0 and less than or equal to that of the mask body 4/5 times the thickness, the depth size range of the slit pattern forming part connected to the small diameter end of the first cavity part is smaller than the thickness of the mask body and greater than or equal to 1/5 times the thickness of the mask body, etc. As a result, each opening slit of the slit pattern structure can be formed by etching the first stage of the opening slit, and then laser cutting is used to obtain the accurate shape and size of the slit pattern forming part , And through the two-stage processing method of etching first and then laser cutting, combined with the depth size control of the first cavity part and the slit pattern forming part, it can achieve a specific sharp-angled opening slit with high resolution Shape, shorten the processing time of the high-energy laser beam in the cutting slit pattern forming part of the thin mask body, effectively overcome the deformation caused by the high temperature of the laser cutting, and make the metal mask easy to control and make Fine slit patterns improve the product yield of metal masks.

Furthermore, in the structure of the metal mask of the present invention, since no additional plating layer is required, the life of the metal mask can be increased, and further, the disadvantages of the 0.1mm sheet thickness that cannot meet the fine slit dimensional accuracy requirements and low resolution can be overcome.

The metal mask of the present invention can further enable the opening slit to include an etched and formed second cavity portion, the second cavity portion being from the second side surface of the mask body to the first side surface with decreasing size Oblique recesses, both ends of the slit pattern forming portion are respectively connected to the small diameter end of the first recess portion and the small diameter end of the second recess portion, and the second recess portion is located on the mask body The second side of the metal mask can effectively avoid the shadow effect of the coating during the coating process, thereby controlling the quality of the coating shape and size of the micro-fine slit pattern.

In the following, in conjunction with the drawings and preferred embodiments of the present invention, the technical means adopted by the present invention to achieve the intended purpose of the invention are further described.

The metal mask proposed in the present invention is used as a common metal mask (CMM) used in the OLED coating process. As shown in FIG. 1 to FIG. 4, several preferred embodiments of the metal mask proposed in the present invention are: The metal mask is a sheet-shaped flat object made of a metal material with a low coefficient of thermal expansion (CTE). The metal material with a low coefficient of thermal expansion means that the average coefficient of expansion at room temperature is lower than 2.5×10 ^-6 /℃ metal materials, such as: iron-nickel alloy (Fe-36Ni, Invar) and other materials. The metal mask includes a mask body 10, a plurality of coating pattern forming structures, and a slit pattern structure 20A, 20B.

As shown in FIGS. 3 and 4, the thickness H of the mask body 10 ranges from 15 μm to 150 μm. The opposite sides of the mask body 10 are a first side surface 101 and a second side surface 102, and the mask body 10 The main body 10 defines a reference plane 100 which is substantially parallel to the first side surface 101 and the second side surface 102.

A plurality of the coating pattern forming structures are distributed and formed in the mask body (not shown), and the shape of the coating pattern forming structure is set according to the shape of the pattern coating that the metal mask is to be formed in the coating process, basically Above, each coating pattern forming structure includes a pattern forming hole, which penetrates from the first side surface to the second side surface of the mask body. The aforementioned coating pattern forming structure belongs to the prior art and will not be repeated here.

As shown in FIGS. 1 and 2, the slit pattern structures 20A and 20B are formed in predetermined areas of the mask body 10. The predetermined areas refer to predetermined partial areas or specific areas of the mask body 10. Area, the shape of the slit pattern structure 20A, 20B is set according to the shape of the opening slit coating that the metal mask is scheduled to form in the coating process, and the shape of the opening slit coating corresponds to the compression code aperture ( The coded image set by the coded aperture camera) technology. In the preferred embodiment shown in FIGS. 1 and 2, the slit pattern structure 20A, 20B includes a plurality of opening slits 21A, 21B, and the shape of the opening slits 21A, 21B is an arc shape and a cross shape, respectively The shape of the slit pattern. It should be noted that the shape of the opening slit is not limited to the aforementioned shape.

As shown in the preferred embodiment of FIG. 3, the opening slit 21C penetrates from the first side surface 101 of the mask body 10 to the second side surface 102, and the opening slit 21C includes a first recess portion 22C And a slit pattern forming portion 23C, the first cavity portion 22C is formed in the mask body 10 by etching, and the first cavity portion 22C is formed from the first side surface 101 of the mask body 10 toward the second side surface 102 An oblique cavity with a decreasing size from the outside to the inside, wherein one end of the first cavity portion 22C located on the first side surface 101 of the mask body 10 is a large-diameter end, and the first cavity portion 22C is opposite to the large-diameter end The other end is a small diameter end. The slit pattern forming part 23C is formed by laser cutting in the mask body 10, and the slit pattern forming part 23C extends from the small diameter end of the first cavity part 22C to the second side surface of the mask body 10 102. The peripheral wall 230C of the slit pattern forming portion 23C is substantially perpendicular to the reference plane 100.

As shown in another preferred embodiment of FIG. 4, the opening slit 21D penetrates from the first side surface 101 of the mask body 10 to the second side surface 102, and the opening slit 21D includes a first cavity Portion 22D, a second cavity portion 24D, and a slit pattern forming portion 23D. The first cavity portion 22D and the second cavity portion 24D are etched and formed in the mask body 10, and the slit pattern forming portion 23D The laser is cut into the mask body 10 and is located between the first cavity portion 22D and the second cavity portion 24D to communicate with each other. Wherein, the first cavity portion 22D is formed from the first side surface 101 of the mask body 10 toward the second side surface 102 of the oblique cavity whose size decreases from outside to inside, and the first cavity portion 22D is located on the mask body 10 One end of the first side surface 101 is a large-diameter end, and the other end of the first cavity portion 22D is a small-diameter end relative to the large-diameter end; the second cavity portion 24D is formed from the second portion of the mask body 10 The side surface 102 is an oblique cavity whose size decreases from outside to inward in the direction of the first side surface. The second cavity portion 24D is located at one end of the second side surface 102 of the mask body 10 as a large-diameter end. The second cavity portion 24D is opposite to The other end of the large diameter end is a small diameter end. The slit pattern forming portion 23D is connected to the small diameter end of the first recess portion 22D and the small diameter end of the second recess portion 24D, and the peripheral wall of the slit pattern forming portion 23D is substantially perpendicular to the reference plane 100.

As shown in FIGS. 3 and 4, in the foregoing, the oblique sidewalls 221C, 221D around the first cavity portion 22C, 22D define a reference oblique surface 220C, 220D connected to the large-diameter end and the small-diameter end. a cavity portion 22C, 22D of the oblique peripheral sidewall 221C, 221D of the reference ramp 220C, 220D relative to the interval range of the oblique angle θ of the reference plane 100 is ³⁵⁰ ~ ^850, the first recess portion 22C, The depth dimension Y range of 22D (in the thickness direction) is greater than 0 and less than or equal to 4/5 times the thickness H of the mask body 10, that is, Y=0~(4/5)H. The depth dimension N of the slit pattern forming portions 23C, 23D (in the thickness direction) is less than the thickness H of the mask body 10 and greater than or equal to 1/5 times the thickness H of the mask body 10, that is, Y =(1/5)H~H.

In order to realize the metal mask of the present invention, when manufacturing the metal mask of the preferred embodiment shown in FIG. 3, it is made of iron-nickel alloy (Fe-36Ni, Invar) or other low thermal expansion coefficient metal materials. The thin metal substrate 10A has a first surface and a second surface on opposite sides of the metal substrate 10A, and the thickness of the metal substrate is about 15 μm to 150 μm. After the yellow photolithography step is successively applied to form the first recess portion 22C on the first surface of the metal substrate 10A, the photoresist used in the yellow photolithography step is removed, and then a laser cutting method is used to form a connection in the metal substrate 10A The slit pattern forming part 23C of the first cavity part 22C.

When manufacturing the metal mask of the preferred embodiment shown in FIG. 4, it also uses a thin metal substrate 10A that can be an iron-nickel alloy (Fe-36Ni, Invar) or other metal materials with a low thermal expansion coefficient. The two opposite sides of the metal substrate 10A are respectively a first surface and a second surface, and the thickness of the metal substrate is about 15 μm to 150 μm. The yellow light lithography step is successively applied to form the first recess portion 22D on the first surface of the metal substrate, and the second recess portion 24D is formed on the second surface of the metal substrate 10, and then the light used in the yellow light lithography step is removed Then, a laser cutting method is used to form a slit pattern forming portion 23D connecting the first cavity portion 22D and the second cavity portion 24D in the metal substrate 10 by laser cutting.

From the foregoing description, it can be seen that when the metal mask of the present invention is applied to a common metal mask (CMM) used in the coating process of an OLED display screen with under-screen photography, a thin mask body is constructed with a slit pattern in a predetermined area. Each opening slit includes a first cavity portion formed by etching and a slit pattern forming portion formed by laser cutting, or further includes a second cavity portion formed by etching, and the depth size range of the first cavity portion is set Greater than 0 and less than or equal to 4/5 times the thickness of the mask body, the depth dimension range of the slit pattern forming portion connected to the small diameter end of the first cavity is less than the thickness of the mask body and greater than or equal to 1/5 times the thickness of the mask body, etc., so that each opening slit of the slit pattern structure can be formed by etching the first cavity (or and the first cavity in the first stage of the opening slit). Two cavities), and then laser cutting method to obtain the accurate shape and size of the slit pattern forming part, and through the two-stage processing method of first etching and then laser cutting to match the first cavity part and the slit The depth and size control of both pattern forming parts can achieve a high-resolution and specific sharp-angled opening slit shape, shortening the processing time of the high-energy laser beam in the cutting slit pattern forming part of the thin mask body, which is effective To overcome the deformation caused by the high temperature of laser cutting, the metal mask of the present invention can be easily controlled and made extremely fine slit patterns.

Under the high-precision shape and size control of the slit pattern structure of the metal mask of the present invention, it can add a specific slit pattern to the common metal mask (CMM) of the vapor-deposited film layer in the OLED display screen coating process Structure, through the very fine slit pattern structure, with transparent and or non-transparent coating process to achieve the incident light can penetrate the area to be imaged and re-decoded on the imaging system.

10: Mask body 100: Datum plane 101: first side 102: second side 10A: Sheet metal 20A: Slit pattern structure 20B: Slit pattern structure 21A: Opening slit 21B: Opening slit 21C: Opening slit 21D: Opening slit 22C: The first cavity 22D: The first cavity 220C: Reference slope 220D: Reference slope 221C: oblique side wall 221D: oblique side wall 23C: Slit pattern forming part 230C: The peripheral wall of the slit pattern forming part 23D: Slit pattern forming part 24D: The second cavity H: The thickness of the mask body Y: Depth dimension of the first cavity N: Depth dimension of the slit pattern forming part θ: The oblique angle of the reference slope of the oblique side wall around the first cavity relative to the reference plane 30: sheet metal 31: Opening slit 311: The first cavity 312: The second cavity

FIG. 1 is a schematic partial plan view of a preferred embodiment of the metal mask of the present invention. 2 is a partial plan view of another preferred embodiment of the metal mask of the present invention. Fig. 3 is a schematic cross-sectional view of a preferred embodiment of the opening slit in the metal mask of the present invention. Fig. 4 is a schematic cross-sectional view of another preferred embodiment of the opening slit in the metal mask of the present invention. FIG. 5 is a flowchart of a preferred embodiment of making the opening slit shown in FIG. 3. FIG. FIG. 6 is a flowchart of a preferred embodiment of making the opening slit shown in FIG. 4. FIG. Fig. 7 is a schematic plan view of a conventional thin metal sheet using two-sided yellow light photolithography to form openings and slits.

10: Mask body 100: Datum plane 101: first side 102: second side 21C: Opening slit 22C: The first cavity 220C: Reference slope 221C: oblique side wall 23C: Slit pattern forming part 230C: The peripheral wall of the slit pattern forming part H: The thickness of the mask body Y: Depth dimension of the first cavity N: Depth dimension of the slit pattern forming part θ: The oblique angle of the reference slope of the oblique side wall around the first cavity relative to the reference plane

Claims (2)

A metal mask comprising: a mask body with a low coefficient of thermal expansion, the thickness of which is 15 μm to 150 μm, and two opposite sides in the thickness direction of the mask body are respectively a first side surface and a second side surface, and are defined by A reference plane parallel to the first side surface and the second side surface; a plurality of coating pattern forming structures are formed in the mask body, and each of the coating pattern forming structures includes a pattern forming hole, the pattern The forming hole penetrates from the first side surface to the second side surface of the mask body; and a slit pattern structure formed in a predetermined area of the mask body, the slit pattern structure includes a plurality of opening slits, so The opening slit penetrates from the first side surface to the second side surface of the mask body, and the opening slit includes a first cavity portion formed by etching and a slit pattern forming portion formed by laser cutting. The first cavity portion is an oblique cavity whose size decreases from the first side surface of the mask body toward the second side surface. The range of the angle range of ^{the first cavity is 35 0} ~ 85 ⁰ , the depth size range of the first cavity is greater than 0 and less than or equal to 4/5 times the thickness of the mask body, and the slit pattern forming portion is from the first The small diameter end of the cavity portion extends toward the second side surface, and the side wall of the slit pattern forming portion is perpendicular to the reference plane. The depth dimension of the slit pattern forming portion is smaller than the thickness of the mask body and larger than Or equal to 1/5 times the thickness of the mask body. The metal mask according to claim 1, wherein the opening slit further includes a second recessed portion formed by etching, and the second recessed portion is drawn from the second side surface of the mask body toward the first The two ends of the slit pattern forming part are respectively connected to the small diameter end of the first concave part and the small diameter end of the second concave part.

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