Mask manufacturing method and mask

Abstract

The invention discloses a mask manufacturing method and a mask, and relates to the technical field of silicon-based OLEDs (Organic Light Emitting Diodes), the mask manufacturing method comprises the following steps: providing a silicon-based substrate, forming a metal seed layer on the surface of the silicon-based substrate, forming a first photoresist layer on the surface of the metal seed layer, and forming a second photoresist layer on the surface of the first photoresist layer; and forming a plurality of first windows for exposing part of the metal seed layer on the surface of the first photoresist layer, forming mask layers for filling the first windows on the surface, facing the first windows, of the metal seed layer by an electroforming process, and removing the first photoresist layer, the silicon-based substrate and the metal seed layer to obtain the mask. According to the manufacturing method, the mask plate is manufactured in a mode of combining the photoetching process and the electroforming process, the opening width of the mask plate depends on the exposure, development and photoresist removal precision in the photoetching process, and compared with existing calendering and etching processes, the manufacturing method can reduce the minimum opening size of the mask plate and improve the manufacturing efficiency of the mask plate. Therefore, the mask plate can be applied to manufacturing of a silicon-based OLED display device with higher PPI.

Description

Technical Field

[0001] The invention relates to the technical field of silicon-based OLED, and in particular to a mask manufacturing method and a mask. Background Art

[0002] There are two main process routes for silicon-based OLED to achieve full-color display:

[0003] 1. WOLED+CF silicon-based OLED, that is, using WOLED (White OLED, white organic light-emitting diode) as the backlight, and filtering through CF (Color Filter) to achieve full-color display;

[0004] 2. RGB silicon-based OLED, that is, by directly evaporating organic light-emitting materials onto specific areas on a silicon substrate, RGB sub-pixels are formed to achieve full-color display.

[0005] Compared with the WOLED+CF silicon-based OLED method, the above-mentioned RGB silicon-based OLED method is increasingly used in the silicon-based OLED field because it directly displays the three primary colors, has higher light efficiency and lower energy consumption.

[0006] In the RGB silicon-based OLED process, dense and tiny RGB OLED sub-pixels need to be deposited on the silicon substrate through a mask. The minimum opening size on the mask also corresponds to the minimum size of the RGB OLED sub-pixel. Therefore, if silicon-based OLED display devices want to achieve higher PPI (Pixels Per Inch), the opening size on the mask needs to be reduced.

[0007] The material of the existing sub-pixel mask is mainly Invar (Invar alloy), mainly because Invar is a magnetic material and has a small thermal expansion coefficient. Among them, when the organic light-emitting material is deposited on the backplane in the evaporation chamber, a magnetic suction plate can be set to adsorb the mask to reduce the sagging of the mask under the influence of gravity, thereby reducing the display effect problems caused by uneven deposition of organic light-emitting materials. In addition, the smaller thermal expansion coefficient can reduce the evaporation position deviation of the RGB sub-pixels.

[0008] In the traditional mask manufacturing process, the Invar mask is made by calendering and etching, that is, the Invar mask is thinned by calendering to reduce its thickness; and then the etching process is used to open the positions corresponding to the RGB sub-pixels on the mask to obtain the target shape of the mask. However, due to the limitations of the Invar material and calendering process, the thickness of the Invar mask can only be reduced to a minimum of 15μm, and the size of the opening etched on it is proportional to the thickness of the mask. Limited by the etching technology capabilities, the minimum opening width of the existing mask can only be 15μm.

[0009] In summary, under the existing manufacturing process technology, the thickness and opening size of the Invar mask are relatively large, which makes it difficult for the existing mask to meet the technical requirements of full-color display of silicon-based OLED at high PPI. Summary of the invention

[0010] The main purpose of the present invention is to propose a mask manufacturing method and a mask, aiming to solve the problem that the thickness of the Invar Mask is large and the opening size is large under the existing manufacturing process technology, resulting in the inability to meet the technical requirements of full-color display of silicon-based OLEDs at high PPI.

[0011] In order to achieve the above-mentioned object, the present invention provides a method for manufacturing a mask, which comprises:

[0012] Providing a silicon-based substrate;

[0013] forming a metal seed layer on the surface of the silicon-based substrate;

[0014] forming a first photoresist layer on the surface of the metal seed layer;

[0015] forming a plurality of first windows on the surface of the first photoresist layer to expose a portion of the metal seed layer;

[0016] forming a mask layer filling each of the first windows on a surface of the metal seed layer facing the first windows by an electroforming process;

[0017] The first photoresist layer, the silicon-based substrate and the metal seed layer are removed to obtain a mask.

[0018] In one embodiment of the present invention, the step of forming a mask layer filling each of the first windows on the surface of the metal seed layer facing the first windows by an electroforming process comprises:

[0019] The metal seed layer is electrically connected to an electroforming cathode, and the Invar alloy material is electrically connected to an electroforming anode;

[0020] placing the silicon-based substrate having the metal seed layer formed thereon into an electroforming liquid;

[0021] The electroforming cathode and the electroforming anode are energized for a preset time to obtain the mask layer.

[0022] In one embodiment of the present invention, the step of electrically connecting the metal seed layer to the electroforming cathode comprises:

[0023] Providing a conductive carrier;

[0024] Placing the silicon-based substrate into the conductive carrier so that the metal seed layer contacts the conductive carrier;

[0025] The conductive carrier is electrically connected to the electroforming cathode.

[0026] In one embodiment of the present invention, the step of forming a plurality of first windows on the surface of the first photoresist layer to expose a portion of the metal seed layer comprises:

[0027] Provide a light mask;

[0028] A plurality of light-transmitting openings are provided on the surface of the light mask;

[0029] The surface of the first photoresist layer is exposed and developed through the photomask, so that the first photoresist layer forms a first window between every two adjacent light-transmitting openings.

[0030] In one embodiment of the present invention, the step of removing the first photoresist layer, the silicon-based substrate and the metal seed layer includes:

[0031] removing the first photoresist layer to form a plurality of openings on the surface of the mask layer;

[0032] forming a second photoresist layer on a side of the silicon-based substrate facing away from the metal seed layer;

[0033] exposing and developing the second photoresist layer;

[0034] The first etching area of ​​the silicon-based substrate covering the openings of the mask layer and the second etching area of ​​the metal seed layer covering the openings of the mask layer are sequentially etched to form a support frame composed of the silicon-based substrate and the metal seed layer.

[0035] In one embodiment of the present invention, after the step of removing the first photoresist layer to form a plurality of openings on the surface of the mask layer and before the step of forming a second photoresist layer on the side of the silicon-based substrate facing away from the metal seed layer, the method further includes:

[0036] A third photoresist layer is formed on the surfaces of the mask layer and the metal seed layer, wherein the third photoresist layer covers the surface of the mask layer and fills the openings.

[0037] In one embodiment of the present invention, after the step of etching the second etching area of ​​the metal seed layer covering each of the openings of the mask layer, the method further includes:

[0038] The second photoresist layer and the third photoresist layer are removed.

[0039] The present invention also proposes a mask plate, which includes a supporting frame and a mask layer; the mask layer is arranged on the supporting frame, and a plurality of openings are opened on the surface of the mask layer, and the openings are used to pass through the deposition material when the OLED pixel layer is deposited to form the OLED pixel layer.

[0040] In one embodiment of the present invention, the cross-sectional shape of the opening is a rectangle, the width of the opening is L, and 2um≤L≤15um.

[0041] In one embodiment of the present invention, the support frame is arranged along the edge of the mask layer and is located on one side of the mask layer; the support frame includes a metal seed layer and a silicon-based substrate stacked in sequence along a direction perpendicular to the mask layer, and the metal seed layer is located on the surface of the mask layer.

[0042] In one embodiment of the present invention, the metal seed layer includes a nickel layer and an aluminum layer stacked in sequence in a direction away from the mask layer, and the nickel layer is located on the surface of the silicon-based substrate.

[0043] The mask manufacturing method proposed in the present invention includes forming a metal seed layer on the surface of a provided silicon-based substrate material by using a deposition or coating process; then coating the surface of the metal seed layer with a photoresist to form a first photoresist layer; then exposing and developing the first photoresist layer to form a plurality of first windows on the first photoresist layer, and making the area of ​​the metal seed layer corresponding to the first window exposed in the first window. Then, the Invar alloy material is electroformed on the surface of the metal seed layer exposed in the first window by an electroforming process, that is, the Invar alloy material is filled in the first window to form a mask layer. Since the first photoresist layer is a non-conductive material, the Invar alloy material will not be deposited on the surface of the first photoresist layer during electroforming. Therefore, after the first photoresist layer is removed by an etching process, the area of ​​the original first photoresist layer corresponds to the opening of the mask. The present application manufactures a mask by combining a photolithography process with an electroforming process, wherein the width of the mask opening depends on the accuracy of exposure, development, and degumming during the photolithography process. Compared with the existing calendering and etching processes, the manufacturing method proposed in the present application can reduce the minimum opening size of the mask, so that the mask can be used to manufacture silicon-based OLED display devices with higher PPI. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0045] Figure 1 A flowchart of the steps of a method for manufacturing a mask provided by the present invention in one embodiment;

[0046] Figure 2 for Figure 1 A flowchart of the steps of forming a mask layer filling each first window on the surface of the metal seed layer facing the first window by an electroforming process;

[0047] Figure 3 for Figure 2 A flow chart of the steps of electrically connecting an electroforming cathode to a metal seed layer;

[0048] Figure 4 for Figure 1 A flowchart of the steps of forming a plurality of first windows on the surface of the first photoresist layer to expose a portion of the metal seed layer;

[0049] Figure 5 for Figure 1 A flowchart of the steps of removing the first photoresist layer, the silicon-based substrate and the metal seed layer;

[0050] Figure 6 for Figure 5 A flow chart of the steps before forming a second photoresist layer on the side of the silicon-based substrate facing away from the metal seed layer;

[0051] Figure 7 for Figure 5 A flow chart of the steps after etching the second etching area of ​​the metal seed layer to cover the openings of the mask layer;

[0052] Figure 8 A schematic structural diagram of a first embodiment of a mask manufacturing method provided by the present invention;

[0053] Fig. 9 A schematic structural diagram of a second embodiment of a mask manufacturing method provided by the present invention;

[0054] Fig.10 A schematic structural diagram of a third embodiment of a mask manufacturing method provided by the present invention;

[0055] Fig.11A schematic structural diagram of a fourth embodiment of a mask manufacturing method provided by the present invention;

[0056] Fig.12 A schematic structural diagram of a fifth embodiment of a mask manufacturing method provided by the present invention;

[0057] Fig.13 A schematic structural diagram of a sixth embodiment of a mask manufacturing method provided by the present invention;

[0058] Fig.14 A schematic structural diagram of a seventh embodiment of a method for manufacturing a mask provided by the present invention;

[0059] Fig.15 A schematic structural diagram of an eighth embodiment of a mask manufacturing method provided by the present invention;

[0060] Fig.16 A schematic structural diagram of a ninth embodiment of a method for manufacturing a mask provided by the present invention;

[0061] Fig.17 A schematic structural diagram of a tenth embodiment of a mask manufacturing method provided by the present invention;

[0062] Fig.18 A schematic structural diagram of a mask manufacturing method according to an eleventh embodiment of the present invention;

[0063] Fig.19 A schematic structural diagram of a twelfth embodiment of a mask manufacturing method provided by the present invention;

[0064] Fig. 20 This is a schematic structural diagram of the mask provided by the present invention.

[0065] Description of Figure Numbers:

[0066] 10. Silicon-based substrate; 11. First etching area; 20. Metal seed layer; 21. Second etching area; 30. First photoresist layer; 31. First window; 40. Mask layer; 41. Opening; 50. Second photoresist layer; 60. Third photoresist layer; 70. Photomask; 71. Light-transmitting port; 80. Conductive carrier; 90. Support frame.

[0067] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0070] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0071] The invention provides a method for manufacturing a mask.

[0072] Combination Figure 1 , Figures 8 to 15 as well as Fig. 20 As shown, in one embodiment of the present invention, the mask manufacturing method includes:

[0073] Providing a silicon-based substrate 10;

[0074] S100: forming a metal seed layer 20 on a surface of a silicon-based substrate 10;

[0075] S200: forming a first photoresist layer 30 on the surface of the metal seed layer 20;

[0076] S300: forming a plurality of first windows 31 exposing a portion of the metal seed layer 20 on the surface of the first photoresist layer 30;

[0077] S400: forming a mask layer 40 filling each first window 31 on the surface of the metal seed layer 20 facing the first window 31 by an electroforming process;

[0078] S500: removing the first photoresist layer 30, the silicon-based substrate 10 and the metal seed layer 20 to obtain a mask.

[0079] In this embodiment, the size of the silicon-based substrate 10 can be 4 inches, 6 inches or 12 inches, and the silicon-based substrate 10 is ground and thinned to make its thickness meet the use requirements. The metal seed layer 20 can be composed of one or more metal composite coating materials such as nickel (Ni), aluminum (Al), titanium (Ti), etc. The metal seed layer 20 can be formed on the surface of the silicon-based substrate 10 by a deposition or electroplating process. The formation of the metal seed layer 20 on the substrate is a key step in the production process of the electroforming mask, and its main purposes and functions include:

[0080] 1. Conductivity: The electroforming process requires current to pass through the electroforming cathode and the electroforming anode, and the substrate material (such as silicon) is usually a semiconductor. By depositing a metal seed layer 20 on the silicon-based substrate 10, the metal seed layer 20 can be used as an electroforming cathode, allowing current to flow during the electroforming process, thereby achieving the reduction of the metal ions of the mask material and deposition on the surface of the metal seed layer 20.

[0081] 2. Providing nucleation points: The metal seed layer 20 provides nucleation points for the metal particles of the mask material in the electroforming liquid to be converted into the solid mask layer 40 during the electroforming process, that is, the metal cations are first deposited on the metal seed layer 20 after being reduced in the electroforming liquid. These initially deposited metals form the attachment basis for subsequent deposition and promote the uniform growth of the electroforming layer.

[0082] 3. Improve adhesion: The metal seed layer 20 can increase the adhesion between the mask layer 40 and the silicon-based substrate 10. Compared with silicon, the lattice structure of the composite coating material of the metal seed layer 20 is closer to the mask layer 40 material (Invar alloy) and the silicon-based substrate 10, so the metal seed layer 20 has a good bonding force with the substrate and the electroforming material, which helps to improve the bonding force between the mask layer 40 and the substrate, and prevent the mask layer 40 from peeling off or falling off from the silicon-based substrate 10 during subsequent processing.

[0083] A photoresist is applied to the surface of the metal seed layer 20 to form a first photoresist layer 30, and a plurality of first windows 31 are formed on the first photoresist layer 30 by a photolithography process, so that the metal seed layer 20 is partially blocked by the first photoresist layer 30 and partially exposed through the first windows 31. Since the first photoresist layer 30 is an organic material with insulating properties, during electroforming, the mask material (Invar alloy) will be deposited and filled on the surface of the metal seed layer 20 at the first windows 31. After the electroforming is completed, the first photoresist layer 30 between the first windows 31 is etched away, so that the openings 41 of the mask layer 40 are formed.

[0084] As can be seen from the above, the mask manufacturing method proposed in the present application does not directly etch the mask layer 40, but uses a process combining photolithography and electroforming to first expose and develop the first photoresist layer 30, then electroform, and then etch the first photoresist layer 30, and finally form a mask. Therefore, the size of the opening 41 on the surface of the mask is related to the accuracy of the photolithography process. Compared with the existing process of making a mask by rolling and etching, the manufacturing method proposed in the present application can reduce the minimum opening size of the mask, so that the mask can be used to manufacture silicon-based OLED display devices with higher PPI.

[0085] like Figure 2 As shown, in one embodiment of the present invention, the step of forming a mask layer 40 filling each first window 31 on the surface of the metal seed layer 20 facing the first window 31 by an electroforming process includes:

[0086] S410: electrically connecting the metal seed layer 20 to the electroforming cathode, and electrically connecting the Invar alloy material to the electroforming anode;

[0087] S420: placing the silicon-based substrate 10 formed with the metal seed layer 20 into an electroforming liquid;

[0088] S430: Powering on the electroforming cathode and the electroforming anode for a preset time to obtain a mask layer 40.

[0089] In this embodiment, the mask material is made of electroformed metal material, that is, made of Invar alloy material. The metal seed layer 20 and the mask material are connected to the cathode and anode of the power supply through wires, respectively, wherein the wires can be electrically connected to the metal seed layer 20 by means of conductive adhesives or welding, etc.; the wires can also be connected to a clamping device, and the clamping device is clamped on the silicon-based substrate 10 with the seed layer deposited thereon, so as to achieve electrical connection between the cathode of the power supply and the metal seed layer 20; the silicon-based substrate 10 with the metal seed layer 20 deposited thereon can also be placed in a conductive carrier 80, and the wires are electrically connected to the conductive carrier 80, so as to achieve electrical connection between the cathode of the power supply and the metal seed layer 20.

[0090] The electroforming cathode (i.e., the silicon-based substrate 10 formed with the metal seed layer 20) and the electroforming anode (i.e., the mask material) are placed in an electroforming tank, into which an electroforming liquid is injected, and the electroforming anode and the electroforming cathode are electrically connected through the electroforming liquid containing metal ions. When the power is turned on, the metal atoms of the electroforming anode lose electrons and become metal cations that enter the electroforming liquid, while the electroforming cathode attracts these metal ions, causing them to gain electrons and be reduced to metal atoms, and deposited on the surface of the electroforming cathode to form an electroforming layer (i.e., the portion of the metal seed layer 20 exposed at the first window 31). The mask layer 40 of the desired thickness is obtained by controlling the current density and electroforming time of the electroforming process.

[0091] In addition, since the metal ions of the mask material will be deposited and fill each first window 31 during the electroforming process, when the thickness of the mask layer 40 required for electroforming is greater than the depth of the first window 31, the mask layer 40 that is higher than the surface of the first photoresist layer 30 will present a round arch shape during electroforming, resulting in the final mask plate surface being uneven and the molding accuracy of the mask plate opening 41 cannot meet the requirements.

[0092] Therefore, when the first photoresist layer 30 is coated on the surface of the metal seed layer 20, the thickness of the coated first photoresist layer 30 is controlled to be greater than or equal to the thickness of the mask layer 40 required for electroforming, that is, the depth of the first window 31 is greater than or equal to the thickness of the mask layer 40 required for electroforming, so that after the electroforming is completed, the height of the mask layer 40 is flush with or lower than the first photoresist layer 30, so as to ensure that the processing accuracy of the mask plate meets the requirements.

[0093] Combination Figure 3 and Fig.13 As shown, in one embodiment of the present invention, the step of electrically connecting the metal seed layer 20 to the electroforming cathode includes:

[0094] Providing a conductive carrier 80;

[0095] S411: placing the silicon-based substrate 10 into the conductive carrier 80 so that the metal seed layer 20 is in contact with the conductive carrier 80;

[0096] S412: Electrically connect the conductive carrier 80 to the electroforming cathode.

[0097] In this embodiment, the conductive carrier 80 is made of copper (Cu) material. In addition, a layer of nickel or chromium is electroplated on the outer surface of the conductive carrier 80 to further improve the conductivity and corrosion resistance of the conductive carrier 80. The size of the conductive carrier 80 matches the size of the silicon-based substrate 10. The silicon-based substrate 10 is placed in the conductive carrier 80, and the portion of the metal seed layer 20 around the conductive carrier 80 is in contact with the conductive carrier 80, so that the metal seed layer 20 is electrically connected to the conductive carrier 80. The conductive carrier 80 is electrically connected to the cathode of the electroforming power supply, thereby realizing the electrical connection between the metal seed layer 20 and the cathode of the power supply. Compared with the method of directly electrically connecting the metal seed layer 20 to the cathode of the power supply, the metal seed layer 20 in this embodiment is connected to the cathode of the power supply through the conductive carrier 80, and the wire of the cathode of the power supply can be connected to the conductive carrier 80 by welding, or it can be connected to the conductive carrier 80 by clamping a clamping device. These connection methods will not cause damage to the silicon-based substrate 10 and the metal seed layer 20, so as to improve the production yield of the mask.

[0098] Combination Figure 4 , Fig.11 , Fig.12As shown, in one embodiment of the present invention, the step of forming a plurality of first windows 31 exposing a portion of the metal seed layer 20 on the surface of the first photoresist layer 30 includes:

[0099] Providing a light mask 70;

[0100] S310: Opening a plurality of light-transmitting openings 71 on the surface of the light mask 70;

[0101] S320 : exposing and developing the surface of the first photoresist layer 30 through the mask 70 , so that a first window 31 is formed between every two adjacent light-transmitting openings 71 of the first photoresist layer 30 .

[0102] In the present embodiment, the photomask 70 is used to transfer the prefabricated pattern to the first photoresist layer 30. Specifically, the photoresist of the first photoresist layer 30 is a negative photoresist. In the exposure reaction, the chemical structure of the part of the first photoresist layer 30 exposed by ultraviolet light will change, so that the photoresist in the exposed area becomes insoluble in the developer. In the development process, the unexposed photoresist part is dissolved by the developer, while the exposed photoresist part is retained, so that the pattern of the light-transmitting opening 71 of the photomask 70 is transferred to the first photoresist layer 30. Therefore, by controlling the position, size, shape and spacing of the light-transmitting opening 71 of the photomask 70, the position, size, shape and spacing of the first window 31 can be controlled, thereby realizing the control of the position, size, shape and spacing of the mask opening 41. For example, in this embodiment, the light-transmitting opening 71 of the mask 70 corresponds to the opening 41 on the final mask plate, so the width of the light-transmitting opening 71 of the mask 70 is controlled to be 2um-15um, and the opening 41 with a width of 2um-15um can be obtained on the mask plate.

[0103] Combination Figure 5 , Figures 16 to 19 As shown, in one embodiment of the present invention, the step of removing the first photoresist layer 30, the silicon-based substrate 10 and the metal seed layer 20 includes:

[0104] S510: removing the first photoresist layer 30 to form a plurality of openings 41 on the surface of the mask layer 40;

[0105] S520: forming a second photoresist layer 50 on a side of the silicon-based substrate 10 facing away from the metal seed layer 20;

[0106] S530: exposing and developing the second photoresist layer 50;

[0107] S540: Sequentially etch the first etching region 11 of the silicon-based substrate 10 covering the openings 41 of the mask layer 40 and the second etching region 21 of the metal seed layer 20 covering the openings 41 of the mask layer 40 to form a support frame 90 consisting of the silicon-based substrate 10 and the metal seed layer 20.

[0108] In this embodiment, when the mask plate made by the present application is used to deposit the organic light-emitting material, the mask layer 40 and the evaporation platform are spaced apart, so a support frame 90 needs to be provided on one side of the mask layer 40 to raise the mask layer 40 to a certain height. When making the mask plate, the metal seed layer 20 and the silicon-based substrate 10 on one side of the mask layer 40 are etched to form the support frame 90. Compared with the solution of setting the support frame 90 on the mask layer 40 by welding, this embodiment simplifies the process steps and also improves the processing accuracy of the support frame 90.

[0109] Specifically, in the present embodiment, the photoresist is first coated on the side of the silicon-based substrate 10 away from the metal seed layer 20 by spin spraying to form a second photoresist layer 50. Then the second photoresist layer 50 is exposed and developed. After the development is completed, the first etching area 11 of the silicon-based substrate 10 is exposed, while other areas are blocked by the second photoresist layer 50. Then, different chemical solvents or etching gases are used in turn to remove the first etching area 11 of the silicon-based substrate 10 and the second etching area 21 of the metal seed layer 20, and finally the openings 41 of the mask layer 40 are exposed. The silicon-based substrate 10 and the metal seed layer 20 that are not etched and are blocked by the second photoresist layer 50 together constitute a support frame 90. According to the actual needs when depositing organic materials, the support frame 90 is etched into different shapes and sizes.

[0110] Combination Figure 6 and Fig.16 As shown, in one embodiment of the present invention, after the step of removing the first photoresist layer 30 to form a plurality of openings 41 on the surface of the mask layer 40 and before the step of forming a second photoresist layer 50 on the side of the silicon-based substrate 10 away from the metal seed layer 20, the step further includes:

[0111] S511 : forming a third photoresist layer 60 on the surfaces of the mask layer 40 and the metal seed layer 20 . The third photoresist layer 60 covers the surface of the mask layer 40 and fills the openings 41 .

[0112] When performing processes such as photolithography, electroforming, and etching, the photolithography area, electroforming area, and etching area usually need to face upward, that is, when the mask layer 40 is completed, before etching the silicon-based substrate 10 and the metal seed layer 20, the wafer needs to be flipped so that the mask layer 40 faces downward and the silicon-based substrate 10 faces upward.

[0113] Therefore, in this embodiment, before applying the second photoresist layer 50, the third photoresist layer 60 is first applied on the surface of the mask layer 40. The addition of the third photoresist layer 60 can protect the mask layer 40 from damage during the subsequent development, etching and flipping processes.

[0114] Combination Figure 7 , Fig.19 as well as Fig. 20 As shown, in one embodiment of the present invention, after the step of etching the second etching area 21 of the metal seed layer 20 covering each opening 41 of the mask layer 40, the method further includes:

[0115] S550 : removing the second photoresist layer 50 and the third photoresist layer 60 .

[0116] In this embodiment, the second photoresist layer 50 and the third photoresist layer 60 can be removed by a developer or by plasma etching. After removing the second photoresist layer 50 and the third photoresist layer 60, the mask layer 40 and the support frame 90 are completely exposed, forming a complete mask structure.

[0117] The present invention also provides a mask, and the method for making the mask is similar to the above embodiment. Fig. 20 As shown, the mask plate includes a support frame 90 and a mask layer 40. The mask layer 40 is arranged on the support frame 90. A plurality of openings 41 are opened on the surface of the mask layer 40. The openings 41 are used to pass through the deposition material when the OLED pixel layer is deposited to form the OLED pixel layer.

[0118] In this embodiment, when the mask is used to make a high-resolution OLED display device, the organic light-emitting material is deposited on the backplane. The mask layer 40 is made of Invar alloy material, which has a low thermal expansion coefficient to adapt to the high-temperature deposition process. At the same time, the mask layer 40 has magnetism. When depositing the organic light-emitting material, a magnetic suction plate can be set on the side of the backplane away from the mask, so that the mask is attached to the surface of the backplane under the magnetic force of the magnetic suction plate, avoiding the middle area of ​​the mask from falling due to gravity, thereby solving the problem of uneven deposition when depositing the organic light-emitting layer.

[0119] The support frame 90 provides good mechanical support for the mask layer 40, and the support frame 90 avoids the opening 41 of the mask layer 40, so that when the organic light-emitting material is deposited, the mask layer 40 is spaced apart from the evaporation platform. The thickness of the support frame 90 can be set according to the spacing requirement between the mask layer 40 and the evaporation platform when the organic light-emitting material is deposited, and no further limitation is made here.

[0120] In one embodiment of the present invention, the cross-sectional shape of the opening 41 is rectangular, and the width of the opening 41 is L, 2um≤L≤15um. By controlling the size, shape, and spacing of the first window 31 opened in the first photoresist layer 30 during mask production, a mask with the required size and shape of the opening 41 is obtained. When depositing the organic light-emitting material, the pattern of the opening 41 is transferred to the OLED pixel layer through the mask to obtain an RGB pixel unit with the same size as the opening 41, so as to meet the precision requirements of the high PPI display device.

[0121] Combination Fig. 20 As shown, in one embodiment of the present invention, the support frame 90 is arranged along the edge of the mask layer 40 and on one side of the mask layer 40; the support frame 90 includes a metal seed layer 20 and a silicon-based substrate 10 stacked in sequence along a direction perpendicular to the mask layer 40, and the metal seed layer 20 is located on the surface of the mask layer 40.

[0122] In this embodiment, the support frame 90 can be set to be annular so that it has a larger contact area with the mask layer 40, and the support force for different positions of the mask layer 40 is more uniform. The outer peripheral surface of the support frame 90 is set flush with the outer peripheral surface of the mask layer 40. The support frame 90 includes a metal seed layer 20 and a silicon-based substrate 10 stacked in sequence in a direction perpendicular to the mask layer 40. The metal seed layer 20 can be one or more combinations of metal materials such as nickel, aluminum, copper, and titanium. The metal seed layer 20 improves the adhesion between the mask layer 40 and the silicon-based substrate 10 to ensure that the mask has good mechanical stability and thermal stability.

[0123] Combination Fig. 9 As shown, in one embodiment of the present invention, the metal seed layer 20 includes a nickel layer and an aluminum layer stacked in sequence in a direction away from the mask layer 40 , and the nickel layer is located on the surface of the silicon-based substrate 10 .

[0124] In this embodiment, the nickel layer is more compatible with the lattice structure of the silicon-based substrate 10 and has better bonding strength. The aluminum layer is more compatible with the lattice structure of the electroformed mask layer 40 and has better bonding strength. Therefore, this double-layer structure design further enhances the bonding strength between the silicon-based substrate 10 and the mask layer 40. In other embodiments, nickel and aluminum can also be doped together to form a metal seed layer 20.

[0125] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a mask, characterized in that: The mask manufacturing method comprises: Providing a silicon-based substrate; forming a metal seed layer on the surface of the silicon-based substrate; forming a first photoresist layer on the surface of the metal seed layer; forming a plurality of first windows on the surface of the first photoresist layer to expose a portion of the metal seed layer; forming a mask layer filling each of the first windows on a surface of the metal seed layer facing the first windows by an electroforming process; The first photoresist layer, the silicon-based substrate and the metal seed layer are removed to obtain a mask.

2. The method for manufacturing a mask according to claim 1, wherein: The step of forming a mask layer filling each of the first windows by electroforming on the surface of the metal seed layer facing the first windows comprises: The metal seed layer is electrically connected to an electroforming cathode, and the Invar alloy material is electrically connected to an electroforming anode; placing the silicon-based substrate having the metal seed layer formed thereon into an electroforming liquid; The electroforming cathode and the electroforming anode are energized for a preset time to obtain the mask layer.

3. The method for manufacturing a mask according to claim 2, wherein: The step of electrically connecting the metal seed layer to the electroforming cathode comprises: Providing a conductive carrier; Placing the silicon-based substrate into the conductive carrier so that the metal seed layer contacts the conductive carrier; The conductive carrier is electrically connected to the electroforming cathode.

4. The method for manufacturing a mask according to any one of claims 1 to 3, characterized in that: The step of forming a plurality of first windows on the surface of the first photoresist layer to expose a portion of the metal seed layer comprises: Provide a light mask; A plurality of light-transmitting openings are provided on the surface of the light mask; The surface of the first photoresist layer is exposed and developed through the photomask, so that the first photoresist layer forms a first window between every two adjacent light-transmitting openings.

5. The method for manufacturing a mask according to any one of claims 1 to 3, characterized in that: The step of removing the first photoresist layer, the silicon-based substrate and the metal seed layer comprises: removing the first photoresist layer to form a plurality of openings on the surface of the mask layer; forming a second photoresist layer on a side of the silicon-based substrate facing away from the metal seed layer; exposing and developing the second photoresist layer; The first etching area of ​​the silicon-based substrate covering the openings of the mask layer and the second etching area of ​​the metal seed layer covering the openings of the mask layer are sequentially etched to form a support frame composed of the silicon-based substrate and the metal seed layer.

6. The method for manufacturing a mask according to claim 5, wherein: After the step of removing the first photoresist layer to form a plurality of openings on the surface of the mask layer, and before the step of forming a second photoresist layer on the side of the silicon-based substrate facing away from the metal seed layer, the method further includes: A third photoresist layer is formed on the surfaces of the mask layer and the metal seed layer, wherein the third photoresist layer covers the surface of the mask layer and fills the openings.

7. The method for manufacturing a mask according to claim 6, wherein: After the step of etching the second etching area of ​​the metal seed layer covering each of the openings of the mask layer, the step further includes: The second photoresist layer and the third photoresist layer are removed.

8. A mask, characterized in that: The mask comprises: Support frame; A mask layer, wherein the mask layer is arranged on the support frame, and a plurality of openings are opened on the surface of the mask layer, and the openings are used to pass through the deposition material when the OLED pixel layer is deposited to form the OLED pixel layer.

9. The mask according to claim 8, characterized in that: The cross-sectional shape of the opening is a rectangle, the width of the opening is L, and 2um≤L≤15um.

10. The mask according to any one of claims 8 or 9, characterized in that: The support frame is arranged along the edge of the mask layer and is located on one side of the mask layer; the support frame includes a metal seed layer and a silicon-based substrate stacked in sequence along a direction perpendicular to the mask layer, and the metal seed layer is located on the surface of the mask layer.

11. The mask according to claim 10, characterized in that: The metal seed layer comprises a nickel layer and an aluminum layer which are sequentially stacked in a direction perpendicular to the mask layer, and the nickel layer is located on the surface of the silicon-based substrate.

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