阅读说明：本技术 一种金属掩膜版的加工方法 (Processing method of metal mask ) 是由 钱超 杨柯 吴建 于 2021-09-06 设计创作，主要内容包括：本发明提出的一种金属掩膜版的加工方法,涉及蒸镀掩膜领域。该加工方法在金属片上分三步依次蚀刻加工出第一凹槽、两个第二凹槽和第三凹槽；控制第一凹槽的宽度为d1、深度为h1；控制第二凹槽的宽度为d2′、深度为h2,两个第二凹槽相远端的距离为d2；第三凹槽蚀刻至与两个第二凹槽上下贯通形成一个呈整体的贯通孔,该贯通孔中,以所述的第三凹槽的侧壁与第二凹槽的侧壁的交界处为分界,形成宽度为d2、深度为h2′的上部孔体和宽度为d3、深度为h3的下部孔体。利用本发明的加工方法,能够有效控制所述的上部孔体和下部孔体的尺寸精度和一致性,大幅度提高了金属掩膜版的产出良率和一致性。(The invention provides a processing method of a metal mask plate, and relates to the field of evaporation masks. The processing method comprises the steps of sequentially etching and processing a first groove, two second grooves and a third groove on a metal sheet in three steps; controlling the width of the first groove to be d1 and the depth to be h 1; controlling the width of the second groove to be d 2', the depth to be h2, and the distance between the far ends of the two second grooves to be d 2; the third groove is etched to vertically penetrate the two second grooves to form an integral through hole, and an upper hole body with the width of d2 and the depth of h 2' and a lower hole body with the width of d3 and the depth of h3 are formed in the through hole by taking the boundary of the side wall of the third groove and the side wall of the second groove as a boundary. By utilizing the processing method, the dimensional accuracy and the consistency of the upper hole body and the lower hole body can be effectively controlled, and the yield and the consistency of the metal mask are greatly improved.)

1. A processing method of a metal mask is characterized by comprising the following steps:

s01, first-step etching: taking a metal sheet with the thickness of h0, etching a first groove (1) on the upper side surface of the metal sheet, and controlling the width of the first groove (1) to be d1 and the depth to be h 1;

s02, etching in the second step: etching two second grooves (2) at the bottom of the first groove (1), wherein the two second grooves (2) are symmetrical relative to the center line of the first groove (1), the distance between the far ends of the two second grooves (2) is controlled to be d2, and the width of the second groove (2) is controlled to be d 2' and the depth of the second groove (2) is controlled to be h 2;

s03, etching in the third step: etching a third groove (3) on the lower side surface of the metal sheet until the third groove and the two second grooves (2) are vertically penetrated to form an integral through hole;

in the through hole, an upper hole body (5) with the width of d2 and the depth of h 2' and a lower hole body (6) with the width of d3 and the depth of h3 are formed by taking a boundary (4) between the side wall of the third groove (3) and the side wall of the second groove (2) as a boundary.

2. The method for processing the metal mask as claimed in claim 1, wherein the thickness h0 of the metal sheet, the depth h1 of the first groove (1), the depth h2 of the second groove (2) and the depth h 2' of the upper hole body (5) satisfy: h2 '< h2 ≤ h1, and (h1+ h 2')/h 0 ≤ 0.3.

3. The method of claim 2, wherein the depth h 2' of the upper aperture body (5) is not more than two-thirds of the depth h2 of the first groove (1).

4. The method of claim 2, wherein:

the thickness h0 of the metal sheet is 100-200 mu m;

the depth h1 of the first groove (1) is 10-20 mu m;

the depth h2 of the second groove (2) is 10-15 mu m;

the depth h 2' of the upper hole body (5) is less than or equal to 10 mu m.

5. The method as claimed in claim 4, wherein the metal sheet has a thickness h0 of 100 μm or 150 μm or 200 μm.

6. The method for processing the metal mask as claimed in claim 1, wherein the width d1 of the first groove (1), the width d2 of the upper hole body (5) and the width d3 of the third groove (3) satisfy: d1-d2 is 300-400 μm, and d3-d2 is 150-200 μm.

7. The method for processing the metal mask according to claim 1, wherein the width d 2' of the second groove (2) is 0.5-5 mm.

8. The method for processing the metal mask according to claim 7, wherein the width d 2' of the second groove (2) is 0.5-1 mm.

9. The method for processing the metal mask according to claim 1, wherein the inclination angle α of the sidewall of the lower hole body (6) and the inclination angle θ of the sidewall of the upper hole body (5) satisfy: alpha + theta is 105-120 deg.

10. The method for processing the metal mask according to claim 9, wherein the inclination angle α of the sidewall of the lower hole body (6) is 40 ° to 60 °.

Technical Field

The invention relates to the technical field of evaporation masks, in particular to a method for processing a metal mask.

Background

OLED display devices are increasingly used because of their advantages of self-emission, bright color, low power consumption, wide viewing angle, etc. At present, an evaporation technology is commonly used in the fabrication of OLED display devices, wherein a Metal Mask (Mask for short) can effectively control the position of organic material deposited on a substrate, and plays an extremely important role in the whole OLED display device production process. The Metal Mask mainly comprises a Common Metal Mask (CMM) and a precise Metal Mask (FMM), wherein the CMM is used for evaporating a Common layer, and the FMM is used for evaporating a luminous layer.

In the past, in the process of evaporating the common layer, the edge of a display is easily scratched, and the edge of an evaporated film layer has the problems of a shadow area and the like; in addition, foreign matter is easily filled between the CMM and the substrate in the through hole of the deposition pattern on the CMM, and the accuracy of the edge of the deposition film layer is affected. The above problems result in extremely low yield and high production cost of the OLED display device during the evaporation process. Therefore, in order to solve the above problems, developers design the through-hole on the CMM in a shape as shown in fig. 3. Based on the improvement, the problems of scratch and foreign matters are effectively solved, and the width of a shadow area at the edge of the film layer can be reduced to about 15 mu m.

Generally, when the CMM with the shape as shown in fig. 3 is prepared, two etching processes are generally adopted, and the CMM produced by the processing method has low yield and poor consistency, and the yield of the evaporation process of the OLED display device is reduced under the influence of the poor consistency of the CMM; in addition, as the border design of the display edge becomes narrower and narrower, even a borderless display appears, the width of the "shadow" area at the edge of the common layer film layer needs to be further reduced to obtain better user experience. To overcome the above problems, a solution is needed.

Disclosure of Invention

In order to solve the problems of low yield and poor consistency of the CMM produced when the CMM with the shape shown in FIG. 3 is etched twice in the prior art, the invention provides a method for processing a metal mask.

The invention provides a processing method of a metal mask, which comprises the following steps:

s01, first-step etching: taking a metal sheet with the thickness of h0, etching a first groove on the upper side of the metal sheet, and controlling the width of the first groove to be d1 and the depth to be h 1;

s02, etching in the second step: etching two second grooves at the bottom of the first groove, wherein the two second grooves are symmetrical relative to the center line of the first groove, the distance between the far ends of the two second grooves is controlled to be d2, and the width of the second groove is controlled to be d 2' and the depth of the second groove is controlled to be h 2;

s03, etching in the third step: etching a third groove on the lower side surface of the metal sheet until the third groove and the two second grooves are vertically communicated to form an integral through hole;

in the through hole, an upper hole body with the width of d2 and the depth of h 2' and a lower hole body with the width of d3 and the depth of h3 are formed by taking the boundary of the side wall of the third groove and the side wall of the second groove as a boundary.

Further, the thickness h0 of the metal sheet, the depth h1 of the first groove, the depth h2 of the second groove and the depth h 2' of the upper hole body satisfy that: h2 '< h2 ≤ h1, and (h1+ h 2')/h 0 ≤ 0.3.

Further, the depth h 2' of the upper hole body is not more than two thirds of the depth h2 of the first groove.

Further, wherein:

the thickness h0 of the metal sheet is 100-200 mu m;

the depth h1 of the first groove is 10-20 mu m;

the depth h2 of the second groove is 10-15 mu m;

the depth h 2' of the upper hole body is less than or equal to 10 mu m.

Further, the thickness h0 of the metal sheet is 100 μm or 150 μm or 200 μm.

Further, the width d1 of the first groove, the width d2 of the upper hole body and the width d3 of the third groove satisfy the following conditions: d1-d2 is 300-400 μm, and d3-d2 is 150-200 μm.

Further, the width d 2' of the second groove is 0.5-5 mm.

Furthermore, the width d 2' of the second groove is 0.5-1 mm.

Further, the inclination angle α of the side wall of the lower hole body and the inclination angle θ of the side wall of the upper hole body satisfy: alpha + theta is 105-120 deg.

Furthermore, the inclination angle alpha of the side wall of the lower hole body is 40-60 degrees.

The beneficial effects of the invention are as follows:

(1) by adopting the etching process of the three steps S01-S03, the dimensional accuracy and consistency of the upper hole body and the lower hole body can be effectively controlled, and the yield and consistency of the metal mask can be greatly improved;

(2) by optimizing relevant parameters such as the sizes of the first groove, the upper hole body and the lower hole body, the width of a shadow area at the edge of the film layer is greatly reduced.

Drawings

FIG. 1 is a schematic view for explaining a process of manufacturing a metal mask according to the present invention;

FIG. 2 is a schematic structural diagram of a semi-finished product after the second etching step in the present invention;

FIG. 3 is a schematic structural diagram of a metal mask produced by the third etching step of the present invention;

FIG. 4 is a schematic view of a partial structure of the metal mask of FIG. 3;

FIG. 5 is a schematic diagram illustrating a shadow region at the edge of a common layer deposited by a metal mask;

FIG. 6 is a comparison of the edge condition of the isthmus in the through-hole before and after the manufacturing process modification;

in the figure: 1. a first groove; 2. a second groove; 3. a third groove; 4. a juncture; 5. an upper aperture body; 6. a lower hole body; 7. a substrate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. In addition, the terms "first," "second," and "third" are used for convenience of description only and are not to be construed as indicating or implying relative importance.

As an embodiment of the present invention, referring to fig. 1 to 5, a method for processing a metal mask in the embodiment includes the following steps:

s01, first-step etching:

taking a metal sheet with the thickness of h0, wherein the metal sheet is made of materials commonly used for preparing metal masks, such as: invar steel, SUS420 stainless steel, or the like; before etching, coating a layer of photoresist or adhering a layer of photoresist film on the upper and lower sides of the metal sheet, and then exposing and developing the photoresist layer or the photoresist film layer on the upper side by using a Photo Mask to form an opening pattern as shown in fig. 1(a) on the photoresist layer or the photoresist film layer on the upper side; etching the first groove 1 at the opening pattern by dry etching or wet etching, and controlling the width d1 and the depth h1 of the etched first groove 1; after the etching is completed, the residual photoresist layer or photoresist film layer on the surface of the metal sheet is removed, and the structure shown in fig. 1(b) is formed.

S02, etching in the second step:

etching two second grooves 2 at the bottom of the first groove 1, wherein the two second grooves 2 are symmetrical relative to the centerline of the first groove 1, the distance between the two distal ends of the two second grooves 2 is controlled to be d2, and the width of the second groove 2 is controlled to be d 2' and the depth of the second groove 2 is controlled to be h 2. It should be noted that the distal end of the two second grooves 2 refers to the end of the two second grooves 2 which is farthest away. In the second etching step, before etching, a photoresist layer is coated or a photoresist film is attached on both the upper and lower sides of the metal sheet in the same manner as in the first etching step, and an opening pattern as shown in fig. 1(c) is formed by exposing the photoresist layer or the photoresist film layer on the bottom of the first groove 1; after the etching is completed, the remaining photoresist layer or photoresist film layer is removed to form the structure shown in fig. 1 (d).

S03, etching in the third step:

etching a third groove 3 on the lower side surface of the metal sheet until the third groove and the two second grooves 2 are vertically penetrated to form an integral through hole; in the through hole, an upper hole 5 with a width of d2 and a depth of h 2' and a lower hole 6 with a width of d3 and a depth of h3 are formed by taking a boundary 4 between the side wall of the third groove 3 and the side wall of the second groove 2. Here, the width d2 of the upper hole 5 corresponds to the width or length of the region for the vapor deposition common film on the substrate, that is, the width d2 of the upper hole 5 corresponds to the width or length of the region. In the third etching step, before etching, a photoresist is applied to both the upper and lower sides of the metal sheet or a photoresist film is attached thereto, and an opening pattern as shown in fig. 1(e) is formed on the lower side of the metal sheet by exposure, also in the same manner as in the first etching step; after the etching is completed, the remaining photoresist layer or photoresist film layer is removed, and finally the structure shown in fig. 1(f) is formed.

It is worth mentioning that: after the first etching step is completed, the upper hole 5 and the lower hole 6 in the through-hole are generally processed by etching simultaneously in order to save man-hours. However, when the process is performed in this way, the position of the boundary 4 between the upper hole 5 and the lower hole 6 is difficult to be accurately controlled, in other words, the depth of the upper hole 5 and the depth of the lower hole 6 in the through hole fluctuate greatly, and in this case, as shown in fig. 4, the inclination angle α of the side wall of the lower hole 6 and the inclination angle θ of the side wall of the upper hole 5 fluctuate greatly and are difficult to be controlled, which results in low CMM yield and poor uniformity, and reduces the yield of the OLED display device.

Different from the processing method adopting two times of etching, the CMM shown in FIG. 3 is processed by adopting a three-time etching mode, after the first groove 1 is etched, the two second grooves 2 are firstly etched at the bottom of the first groove 1 so as to determine the width of the upper hole body 5 in the through hole; on the basis, a third groove 3 is processed by third etching. In this case, the position of the boundary 4 between the upper hole body 5 and the lower hole body 6 can be easily and accurately controlled by only controlling the width and the inclination angle of the third groove 3; in addition, the defect of zigzag shape in fig. 6(a) at the isthmus in the through hole can be effectively improved, so that the isthmus edge is in a more neat state in fig. 6(b), and the isthmus is the junction 4 of the upper hole body 5 and the lower hole body 6. When the processing method is used for processing, the production yield of the CMM can be improved by more than 10 percent, and the consistency of qualified CMM products is greatly improved.

In the conventional study, when a common film is deposited by using a CMM shown in fig. 5, it is generally considered that the region q1 is an effective film layer region of the common film, and the regions q2, q3 and q4 collectively constitute a "shadow" region of the edge of the common film layer, and that "the distance from the upper edge of the upper hole body 5 among the through holes serving as a material passage on the CMM to the substrate 7" and "the incident angle of the deposition film passing through the lower hole body 6 among the through holes" are considered as factors affecting the width of the "shadow" region of the edge of the common film layer.

However, in the present application, it was found that the thickness difference between the common film layers in the q2 region and the q1 region is very small; also, in practical cases, the width of the q2 region is much smaller than the widths of the q3 and q4 regions. Thus, the q2 region has little effect on the "shadow" region of the common film edge, i.e., the q2 region can also be considered as the effective film-layer region of the common film; while the q3 and q4 regions constitute "shaded" regions of the common membrane edge.

Based on the above finding, the processing method of the metal mask plate in this embodiment is further optimized as follows:

on the basis of the processing method of the metal mask, the thickness h0 of the metal sheet, the depth h1 of the first groove 1, the depth h2 of the second groove 2 and the depth h 2' of the upper hole body 5 preferably satisfy the following conditions: h2 '< h2 ≤ h1, and (h1+ h 2')/h 0 ≤ 0.3. In this case, it is helpful to reduce the widths of the q3 and q4 regions. It can be understood that, when the thickness h0 of the metal sheet and the inclination angle α of the side wall of the lower hole 6 are determined, the depth h3 of the lower hole 6 is larger, the depth h 2' of the upper hole 5 is smaller, and the widths of the q3 and q4 regions are smaller.

When the second groove 2 is etched, since the depth of the second groove 2 is small, the inclination angle of the sidewall of the second groove 2 is difficult to control, and thus it is not generally controlled. In the scheme, after three times of etching is adopted, under the condition that the etching depth of the second groove 2 is controlled by the second step of etching, the etching depth of the third groove 3 is controlled by the third step of etching, a part of the bottom of the second groove 2 is purposefully etched, and finally the depth h 2' of the upper hole body 5 is not more than two thirds of the depth h2 of the first groove 1, and in the range, the inclination angle theta of the side wall of the upper hole body 5 is relatively increased, so that the width of the q3 area is favorably reduced.

Based on the above research, when the thickness h0 of the metal sheet is 100 to 200 μm, for example: the depth h1 of the first groove 1, the depth h2 of the second groove 2 and the depth h 2' of the upper porous body 5 are preferably as follows when the depth is 100 μm, 150 μm or 200 μm: h1 is more than or equal to 10 mu m and less than or equal to 20 mu m, h2 is more than or equal to 10 mu m and less than or equal to 15 mu m, and h 2' is more than or equal to 10 mu m.

On the basis of the processing method of the metal mask, the width d1 of the first groove 1, the width d2 of the upper hole body 5 and the width d3 of the third groove 3 preferably satisfy the following conditions: d1-d2 is 300-400 μm, and d3-d2 is 150-200 μm. When the width d2 of the upper hole body 5 is predetermined and the width d1 of the first concave groove 1 satisfies the above-mentioned limitation, "scratches" and "foreign matters" are avoided, and the deformation of the CMM at the through-hole position is reduced, thereby improving the deposition accuracy.

In the above processing method of the metal mask, the width of the second groove 2 is not generally controlled. In the scheme, the width d 2' of the second groove 2 is preferably 0.5-5 mm, so that the difficulty in controlling the etching precision is reduced. More preferably, the width d 2' of the second groove 2 is 0.5-1 mm, in which case, the etching precision can be controlled and the efficiency can be improved.

In the method for processing a metal mask, the inclination angle α of the sidewall of the lower hole 6 and the inclination angle θ of the sidewall of the upper hole 5 preferably satisfy: alpha + theta is 105-120 deg. It should be noted that: the inclination angle α here means an inclination angle of a connecting line between the lower edge and the upper edge of the side wall of the lower hole body 6 in the vertical section of the metal mask as shown in fig. 4; similarly, the inclination angle θ refers to an inclination angle of a line connecting the lower edge and the upper edge of the side wall of the upper hole body 5 in the vertical section. When the inclination angle α of the sidewall of the lower hole body 6 is reduced, the inclination angle θ of the sidewall of the upper hole body 5 should be increased as appropriate, which is advantageous to reduce the width of the above-mentioned q3 and q4 regions. Further preferably, the inclination angle α of the sidewall of the lower hole body 6 is 40 ° to 60 °, for example: 40 °, 45 °, 50 °, 55 ° or 60 °.

Based on the CMM produced after the above improvement, the width of the "shadow" region generated at the edge of the common film layer can be reduced to 10 μm or less when the common film layer is deposited.

It is worth mentioning that: the limiting conditions of the first groove 1, the second groove 2, the upper hole body 5 and the lower hole body 6 are all the preferable results which can be achieved by adopting the three-time etching process, so that the limiting conditions can be changed to obtain better effects under the condition that the etching process of the metal mask is changed; similarly, the present invention is also preferably limited in the range of each parameter, and is not necessarily limited to the above-mentioned limited range, for example: the thickness h0 of the metal sheet may be 50 μm, 300 μm, 400 μm, or the like.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.