Metal mask etching method and metal mask

Abstract

The present invention discloses an etching method of a metal mask and a metal mask, comprising S500: completely coating a resist on the first main surface of a preliminarily etched metal mask substrate and filling a first recessed area, completely coating a resist on the second main surface and filling a second recessed area; S600: fully curing the resist on the first main surface, and making a third hollowed-out area on the second main surface; S700: etching a third recessed area on the third hollowed-out area of ​​the second main surface, the third recessed area, the second recessed area and the first recessed area are connected to form an etching hole, and the etching hole penetrates the metal mask substrate. The present invention reduces the amount of side etching by the process method, so that the thickness of the finished metal mask still maintains the thickness of the metal mask substrate, thereby ensuring the overall structural strength of the finished product.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a metal mask etching method and a metal mask. Background Art

[0002] As the resolution of OLED panels increases, the distance between holes on the precision metal mask must also become closer. For the precision metal mask currently made by etching, due to the characteristics of etching, that is, etching in the depth direction will also be etched to the side. When the hole spacing is reduced with the increase of resolution, the width of the second main surface between adjacent holes will gradually decrease to zero, and even reduce the thickness of the metal substrate, resulting in a significant weakening of the structural strength of the opening area, which is easy to cause creases in the precision metal mask.

[0003] like Figure 1-2 As shown in the figure, it is an etching method in the prior art. After etching is completed, the width of the second main surface between adjacent holes is gradually reduced to zero, and the thickness of the metal mask is also smaller than the thickness of the metal mask substrate, so that H2 Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a metal mask etching method and a metal mask, which reduces the side etching amount by a process method, so that the thickness of the metal mask finished product still maintains the thickness of the metal mask substrate, thereby ensuring the overall structural strength of the finished product.

[0005] The present invention adopts the following technical solutions:

[0006] A method for etching a metal mask comprises the following steps: S500: completely coating a resist on a first main surface of a preliminarily etched metal mask substrate and filling a first recessed area, and completely coating a resist on a second main surface and filling a second recessed area; S600: fully curing the resist on the first main surface, and making a third hollowed-out area on the second main surface; S700: etching a third recessed area in the third hollowed-out area of ​​the second main surface, wherein the third recessed area, the second recessed area and the first recessed area are connected to form an etching hole, wherein the etching hole penetrates the metal mask substrate.

[0007] Preferably, in S500, the resist coated on the second main surface extends beyond the second main surface by 3 um to 20 um.

[0008] ​Preferably, the following steps are also included: S100: providing a metal mask substrate, which includes a first main surface and a second main surface; S200: completely coating the first main surface with an anti-etching agent, and completely coating the second main surface with an anti-etching agent; S300: making a first hollow area on the first main surface to form a reserved etching area, and making a second hollow area on the second main surface to form a reserved etching area, and the first hollow area and the second hollow area are arranged opposite to each other; S400: etching a first recessed area in the first hollow area of ​​the first main surface, and etching a second recessed area in the second hollow area of ​​the second main surface, and the first recessed area and the second recessed area are opposite to each other and do not penetrate each other.

[0009] Preferably, the etching time of the third recessed area in S700 is one fifth of the etching time of the second recessed area in S400.

[0010] A metal mask is processed by the above-mentioned metal mask etching method, and the thickness H2 of the metal mask is equal to the thickness H1 of the metal mask substrate.

[0011] Preferably, the undulation point T on the evaporation slope formed by the third depressed area and the second depressed area is not higher than a line connecting a boundary point O of the first depressed area and a boundary point R of the second depressed area.

[0012] Preferably, the etching hole formed by connecting the third recessed area, the second recessed area and the first recessed area is a gourd-shaped structure.

[0013] Preferably, an angle θ2 between a line connecting the undulation point T and a boundary point R of the second recessed area and the second main surface is ≥80°.

[0014] Preferably, θ2 ≥ 85°.

[0015] Preferably, the angle θ2 is 90 degrees, and the width of the third hollow area W3=W2+T2*(8 / 5), wherein W2 is the width of the second hollow area, and T2 is the lateral etching amount of the second recessed area.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The present invention provides a method for etching a metal mask. During the second etching, the anti-etching agent is completely coated on the second main surface and the second recessed area is filled, and a third hollow area is made on the second main surface. The side etching amount is controlled and reduced, so that the thickness of the finished metal mask still maintains the thickness of the metal mask substrate, thereby ensuring the overall structural strength of the finished product.

[0018] 2. The undulation point T on the evaporation slope formed by the third depression area and the second depression area of ​​the finished metal mask of the present invention is not higher than the line connecting the boundary point O of the first depression area and the boundary point R of the second depression area, which ensures the overall structural strength of the finished product without affecting the subsequent processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of etching process in the prior art.

[0020] Figure 2 Schematic diagram of etching process in the prior art.

[0021] Figure 3 It is a flow chart of the etching process of the present invention.

[0022] Figure 4 Schematic diagram of the etching process of the present invention.

[0023] Figure 5 This is a schematic diagram of the partial structure of the finished metal mask substrate.

[0024] Figure 6 Another schematic diagram of a partial structure of a finished metal mask substrate.

[0025] Figure 7 Schematic diagram of the initial etching state of the metal mask substrate. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the technical solution of the present invention, a detailed description is given below in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1 - Figure 2 FIG. 1 is a schematic diagram of an etching method and a corresponding state of a metal mask in the prior art. When the second etching process is performed, the second concave area of ​​the second main surface is etched into a third concave area until it is penetrated. Such etching will gradually reduce the width of the second main surface between adjacent holes to zero. The thickness of the metal mask is less than the thickness of the metal mask substrate, so that H2

[0028] Example 1

[0029] like Figure 3 - Figure 7 As shown, this embodiment discloses a metal mask etching method, comprising the following steps:

[0030] S100: providing a metal mask substrate, which comprises a first main surface and a second main surface;

[0031] ​In this embodiment, the first main surface is the upper surface of the metal mask substrate, and the second main surface is the lower surface of the metal mask substrate;

[0032] S200: completely coating the first main surface with a resist, and completely coating the second main surface with a resist; the resist on the first main surface may be a photoresist or a resin ink; the resist on the second main surface is preferably a photoresist;

[0033] S300: making a first hollow area on the first main surface to form a reserved etching area, and making a second hollow area on the second main surface to form a reserved etching area, the first hollow area and the second hollow area being arranged opposite to each other;

[0034] S400: etching a first recessed area in the first hollowed-out area of ​​the first main surface, and etching a second recessed area in the second hollowed-out area of ​​the second main surface, wherein the first recessed area and the second recessed area are opposite to each other but not connected;

[0035] In this embodiment, the maximum diameter of the second recessed area is greater than the maximum diameter of the first recessed area. From a cross-sectional view, the second recessed area is a larger semicircular structure, and the first recessed area is a smaller semicircular structure.

[0036] S500: completely coating the first main surface of the metal mask substrate after preliminary etching with a resist and filling up the first recessed area, and completely coating the second main surface with a resist and filling up the second recessed area;

[0037] Among them, coating the first main surface with an anti-etching agent requires forming complete pore filling in the first recessed area without insufficient pore filling or bubble accumulation; the anti-etching agent on the first main surface can use photoresist or resin ink; the anti-etching agent on the second main surface is preferably photoresist.

[0038] The photoresist coating on the second main surface requires that the second recessed area be completely filled without insufficient filling or bubble accumulation;

[0039] Wherein, when coating the second main surface with photoresist, a spray coating method or a slit coating method may be adopted;

[0040] S600: The first main surface is fully cured of the resist, and a third hollow area is made on the second main surface; since the third hollow area has a requirement for pattern accuracy, in this embodiment, the photoresist layer on the second main surface exceeds the second main surface by a thickness range of 3um to 20um, preferably 8um; in this embodiment, the second main surface is fully filled and exceeds a certain height, so that the area that should not be etched can be fully protected;

[0041] Among them, if a photoresist is used for the first main surface, it is cured by exposure; if a resin ink is used for the first main surface, it is thermally cured by baking.

[0042] Specifically, the width of the third hollow area is W3, and development is carried out from the second main surface to the first main surface until the surface of the second concave area is exposed.

[0043] S700: Etch a third concave area in the third hollow area of the second main surface. The third concave area, the second concave area and the first concave area are connected to form an etch hole, and the etch hole penetrates through the metal mask substrate.

[0044] The metal mask finished product etched by the above method reduces the side etch amount of etching, does not affect the width of the second main surface between adjacent holes, and its thickness still maintains the thickness of the metal mask substrate, ensuring the overall structural strength of the finished product.

[0045] Since the etching depth of the third concave area is small, in this embodiment, the etching time of the third concave area in S700 is one-fifth of the etching time of the second concave area in S400.

[0046] A metal mask is processed by the above etching method, and the thickness H2 of the metal mask is equal to the thickness H1 of the metal mask substrate, ensuring the overall structural strength of the finished product.

[0047] Among them, the etch hole formed by connecting the third concave area, the second concave area and the first concave area is in a gourd shape;

[0048] Such as Figure 5 - Figure 6 As shown, the undulation point T (and the inflection point of the gourd shape) on the evaporation slope formed by the third concave area and the second concave area is not higher than the connection line between the boundary point O of the first concave area and the boundary point R of the second concave area. Setting the undulation point T in this way will not affect the subsequent evaporation effect.

[0049] Such as Figure 7 As shown, in this embodiment, the thickness H1 of the metal mask substrate, the depth D1 of the first concave area, the depth D2 of the second concave area, H3 = H1 - D1 - D2;

[0050] Among them, affected by the fluctuation of etching uniformity, to avoid the formation of a connected through hole between the first concave area and the second concave area, in this embodiment, H3 ≥ H1*(1 / 10);

[0051] In order to enable the precision metal mask to have a better evaporation effect during evaporation, in this embodiment, D1 < D2 is defined. In addition,

[0052] The lateral etching amount of the first recessed area T1 = 0.5*(L1-W1), the lateral etching amount of the second recessed area T2 = 0.5*(L2-W2); wherein L1 is the width of the first recessed area, W1 is the width of the first hollowed-out area, L2 is the width of the second recessed area, and W2 is the width of the second hollowed-out area.

[0053] The width of point T = W3 + 2*(T3), W3 is the width of the third hollow area, T3 is the lateral etching amount of the third recessed area, and the angle θ2 between the line connecting the undulation point T and the boundary point R of the second recessed area and the second main surface is ≥80°, that is, the closer the T is to the inside, the better, so θ2 ≥85° is preferred.

[0054] In order to make point T not higher than the line connecting the boundary point O of the first depression area and the boundary point R of the second depression area, the angle θ2 between the line connecting the undulation point T and the boundary point R of the second depression area and the second main surface is ≥80°, that is, the closer the T is to the inside, the better, so θ2 ≥85° is preferably set.

[0055] In this embodiment, the angle θ2 between the line connecting the target undulation point T and the boundary point R and the second main surface is 90°, so the line connecting the undulation point T and the boundary point R is vertically arranged, so W3+2*T3=W2+2*T2, so W3=W2+2*(T2-T3);

[0056] In this embodiment, D2=H1*(1 / 2), H3=H1*(1 / 10);

[0057] Therefore, T2:T3=D2:H3=H1*(1 / 2):H1*(1 / 10)=5:1, and W3=W2+T2*(8 / 5) is obtained, where W2 is the width of the second hollow area and T2 is the lateral etching amount of the second recessed area.

[0058] The width W3 of the third hollow area is limited by the above setting, so that the undulation point T is not higher than the line connecting the boundary point O of the first recessed area and the boundary point R of the second recessed area.

[0059] The above are only preferred embodiments of the present invention. The protection scope of the present invention shall be based on the scope defined by the claims. Several improvements and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for etching a metal mask, characterized in that: The following steps are involved: S100: providing a metal mask substrate, which comprises a first main surface and a second main surface; S200: completely coating the first main surface with a resist, and completely coating the second main surface with a resist; S300: making a first hollow area on the first main surface to form a reserved etching area, and making a second hollow area on the second main surface to form a reserved etching area, the first hollow area and the second hollow area being arranged opposite to each other; S400: etching a first recessed area in the first hollowed-out area of ​​the first main surface, and etching a second recessed area in the second hollowed-out area of ​​the second main surface, wherein the first recessed area and the second recessed area are opposite to each other but not connected; S500: completely coating the first main surface of the metal mask substrate after preliminary etching with a resist and filling up the first recessed area, and completely coating the second main surface with a resist and filling up the second recessed area; S600: the resist is fully cured on the first main surface, and a third hollow area is produced on the second main surface; S700: etching a third recessed area in the third hollowed-out area of ​​the second main surface, wherein the third recessed area, the second recessed area and the first recessed area are connected to form an etching hole, and the etching hole penetrates the metal mask substrate; The etching time of the third recessed area in S700 is one fifth of the etching time of the second recessed area in S400; The undulation point T on the evaporation slope formed by the third depressed area and the second depressed area is not higher than the line connecting the boundary point O of the first depressed area and the boundary point R of the second depressed area.

2. The method for etching a metal mask according to claim 1, characterized in that: In S500 , the resist coated on the second main surface extends beyond the second main surface by 3 um to 20 um.

3. A metal mask, characterized in that: The metal mask is processed by the etching method of any one of claims 1-2, and the thickness H2 of the metal mask is equal to the thickness H1 of the metal mask substrate.

4. A metal mask according to claim 3, characterized in that: The etching hole formed by connecting the third recessed area, the second recessed area and the first recessed area is a gourd-shaped structure.

5. The metal mask according to claim 4, characterized in that: An angle θ2 between a line connecting the undulation point T and a boundary point R of the second concave area and the second main surface is ≥80°.

6. The metal mask according to claim 5, characterized in that: The θ2≥85°.

7. The metal mask according to claim 5, characterized in that: The angle θ2 is 90 degrees, and the width of the third hollow area W3=W2+T2*(8 / 5), wherein W2 is the width of the second hollow area, and T2 is the lateral etching amount of the second recessed area.

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