TW202227650A - Mask, method of manufacturing mask - Google Patents

Abstract

A mask includes a first surface, a second surface, and a plurality of through holes. The second surface is opposite to the first surface, and the second surface has a plurality of convex surfaces. The through holes link the first surface and the second surface, where each of the through holes has a convex sidewall that is connected to the first surface and the second surface.

Description

Mask, method for manufacturing mask, and master mold for mask manufacturing

The present invention relates to a mask, a method for manufacturing the mask, and a master mold for manufacturing the mask, and in particular, to a mask made by electroforming and a method for manufacturing the same, and a mask used for manufacturing the mask. The master mold from which this mask is made.

Some display panels today have been manufactured using a Fine Metal Mask (FMM). Taking an organic light emitting diode (Organic Light Emitting Diode, OLED) display panel as an example, some OLED display panels are currently manufactured by evaporation. During the evaporation process, the fine metal mask is first placed on the glass plate, and is close to or close to the glass plate, so that the plating material produced by evaporation can be deposited on the opening pattern according to the opening pattern of the fine metal mask. on exposed glass.

Existing fine metal masks have upper and lower surfaces opposed to each other and a plurality of openings extending from the upper surface to the lower surface, wherein the openings form an opening pattern. The aperture walls of each opening are generally substantially perpendicular to the upper and lower surfaces. Therefore, during the evaporation process, the plating material from the evaporation source can move to the glass plate along the normal line of the glass plate, thereby being deposited on the glass plate exposed by the opening pattern.

However, since the hole walls of each opening are substantially perpendicular to the upper and lower surfaces, many other plating materials that do not move along the normal line of the glass plate and move toward the glass plate will be blocked by some fine metal masks around the openings. It is difficult for the deposit to completely cover the exposed area of the opening pattern on the glass plate, which causes problems such as pixel color deficiency or pixel color distortion in the organic light emitting diode display panel, resulting in a decrease in yield.

At least one embodiment of the present invention provides a mask with a convex curved surface and a convex wall surface, so as to help the plating material that does not move along the normal line to be smoothly deposited on the substrate to be plated (eg, glass plate).

At least one embodiment of the present invention also provides a method for manufacturing the above-mentioned mask and a master mold for manufacturing the mask.

The mask provided by at least one embodiment of the present invention includes a first surface, a second surface and a plurality of through holes. The second surface is opposite to the first surface, and the second surface has a plurality of convex curved surfaces. The through holes communicate with the first surface and the second surface, wherein each through hole has an outer convex wall surface, which is connected between the first surface and the second surface.

In at least one embodiment of the present invention, each outer convex wall surface is not perpendicular to the first surface.

In at least one embodiment of the present invention, the curvature radius of each convex curved surface of the second surface is larger than the curvature radius of the convex wall surface of each through hole.

In at least one embodiment of the present invention, the above-mentioned mask further includes a plurality of bumps. The bumps are respectively formed on the convex curved surfaces, wherein each of the bumps protrudes from the convex curved surfaces.

In at least one embodiment of the present invention, the material of the mask includes nickel and iron, wherein the weight percentage of nickel in the mask is between 35 and 50%, and the weight percentage of iron in the mask is between 50 and 65%.

At least one embodiment of the present invention provides a master mold for manufacturing the above-mentioned mask, wherein the master mold is made of a conductive substrate, and includes a first plane, a second plane and an engraved pattern. The second plane is relative to the first plane. The engraved pattern is exposed on the first plane, wherein the engraved pattern corresponds to the mask. The engraved pattern has a plurality of cavities, and each cavity has an inner concave curved surface.

In at least one embodiment of the present invention, the depth of each cavity is smaller than the thickness between the first plane and the second plane.

In at least one embodiment of the present invention, the material of the conductive substrate is stainless steel.

In the method for manufacturing a mask provided by at least one embodiment of the present invention, first, a first photoresist layer is formed on a conductive substrate, wherein the conductive substrate has a first plane and a second plane opposite to the first plane, and the first The photoresist layer partially covers the first plane. Next, using the first photoresist layer as a mask, the conductive substrate is etched from the part of the first plane not covered by the first photoresist layer, so as to form a master mold with a plurality of cavities. Next, the master mold is electroformed to deposit metallic material in each cavity. After electroforming of the master mold, the master mold is removed.

In at least one embodiment of the present invention, the method for manufacturing the mask further includes the following steps. After etching the conductive substrate from the portion of the first plane not covered by the first photoresist layer, the first photoresist layer is removed. After removing the first photoresist layer and before electroforming the master mold, a second photoresist layer is formed on the master mold, wherein the second photoresist layer covers the cavities and has a plurality of plated openings, and The plated openings are located within the cavities, respectively.

In at least one embodiment of the present invention, the second photoresist layer remains during electroforming of the master mold.

In at least one embodiment of the present invention, the depth of each cavity is smaller than the thickness between the first plane and the second plane.

In at least one embodiment of the present invention, the first photoresist layer remains during electroforming of the master mold.

In at least one embodiment of the present invention, the method for etching the conductive substrate is wet etching.

Based on the above, since the conductive pattern surface of the mold part and the insulating surface of the masking pattern are cut flush with each other, and during the second electroforming, the metal material will not be deposited on the insulating surface, so there is no space between the conductive pattern surface and the insulating surface. The boundary of the metal pattern (ie, the metal mask) can cause the metal pattern (ie, the metal mask) to form a convex surface, so that the width of the hollow area is not uniform. In this way, the plating material can enter the hollow area from the convex surface, and is smoothly deposited on the plated substrate (such as a glass plate) exposed in the hollow area, which helps to reduce or avoid the occurrence of pixel color deficiency or pixel color distortion. problems, thereby improving yield.

Using the inner concave curved surface of the above-mentioned master mold, a mask with an outer convex curved surface and an outer convex wall surface can be formed, so that during the evaporation process, the mask can help the plating material that does not move along the normal line to be smoothly deposited on the substrate. Coating substrates (such as glass plates) can help reduce or avoid problems such as pixel color deficiency or pixel color distortion, thereby improving yield.

In the following text, the dimensions (such as length, width, thickness and depth) of elements (such as layers, films, substrates and regions, etc.) in the drawings are exaggerated in unequal proportions in order to clearly present the technical features of the present application. . Therefore, the descriptions and explanations of the following embodiments are not limited to the dimensions and shapes of the elements in the drawings, but should cover the dimensions, shapes and deviations caused by actual manufacturing processes and/or tolerances. For example, the flat surfaces shown in the figures may have rough and/or non-linear features, while the acute angles shown in the figures may be rounded. Therefore, the elements shown in the drawings in this application are mainly for illustration, and are not intended to accurately depict the actual shapes of the elements, nor are they intended to limit the scope of the patent application of this application.

Secondly, words such as "about", "approximately" or "substantially" appearing in the content of this case not only cover the clearly stated numerical value and numerical value range, but also cover the understanding of those with ordinary knowledge in the technical field to which the invention belongs. The allowable deviation range of , wherein the deviation range can be determined by the error generated during measurement, for example, the error is caused by the limitations of both the measurement system or the process conditions. Further, "about" can mean within one or more standard deviations of the above-mentioned numerical value, eg, within ±30%, ±20%, ±10%, or ±5%. Words such as "about", "approximately" or "substantially" appearing in this text may be used to select acceptable ranges or standard deviations based on optical properties, etching properties, mechanical properties or other properties, not a single Standard deviation to apply all of the above optical, etch, mechanical and other properties.

1A is a schematic cross-sectional view of a mask according to at least one embodiment of the present invention. Referring to FIG. 1A , the mask 100 includes a first surface 110 and a second surface 120 , wherein the second surface 120 is opposite to the first surface 110 . Taking FIG. 1A as an example, the first surface 110 and the second surface 120 may be opposite sides of the mask 100 , wherein the first surface 110 is the upper surface of the mask 100 , and the second surface 120 is the lower surface of the mask 100 . .

The first face 110 may be flat, but the second face 120 is not. For example, in the embodiment shown in FIG. 1A , the second surface 120 has a plurality of convex curved surfaces 121 . The mask 100 may be made of a metal material, wherein the metal material may be a single metal material or an alloy material. For example, the material of the mask 100 may include nickel and iron, wherein the weight percentage of nickel in the mask 100 may be between 35 and 50%, and the weight percentage of iron in the mask 100 may be between 50 and 65%.

The mask 100 further includes a plurality of through holes 130 , wherein the through holes 130 communicate with the first surface 110 and the second surface 120 . In other words, the through holes 130 extend from the first surface 110 to the second surface 120 and are exposed on the first surface 110 and the second surface 120 . The through holes 130 may be arranged in an array, and the shape of the mask 100 may be a mesh, wherein the through holes 130 may be located in the mesh of the mesh mask 100 .

Each through hole 130 has an outer convex wall surface 131 connected between the first surface 110 and the second surface 120 . Specifically, in the same through hole 130 , the outer convex wall surface 131 protrudes toward the axis A13 of the through hole 130 , so each through hole 130 does not have a uniform width. In addition, each of the protruding wall surfaces 131 is not perpendicular to the first surface 110 , and both ends of each of the through holes 130 do not have a minimum width. In this embodiment, the radius of curvature of each convex curved surface 121 of the second surface 120 may be larger than the radius of curvature of each convex wall surface 131 of each through hole 130 .

FIG. 1B is a schematic cross-sectional view of the metal mask in FIG. 1A applied to evaporation. Referring to FIG. 1B , since the mask 100 has the convex curved surface 121 and the convex wall surface 131 , the widths of the through holes 130 are not uniform. Taking FIG. 1B as an example, each through hole 130 has a width W11 on the first surface 110 and a width W12 on the second surface 120 , wherein the width W12 is significantly larger than the width W11 . During the evaporation process, the mask 100 is adjacent to or abuts against the substrate 101 to be plated, wherein the second surface 120 with the convex curved surface 121 faces the evaporation source 10 , and the first surface 110 faces the substrate 101 to be plated . In addition, the substrate to be plated 101 may be a glass plate, but is not limited thereto.

The width of each through hole 130 is not uniform, so that the plating material 11 from the evaporation source 10 can enter these through holes 130 from the convex curved surface 121 regardless of whether it moves along the normal line 31 of the substrate 101 to be plated. , and are successfully deposited on the plated substrate 101 exposed by the through holes 130 to form a plurality of deposits (not shown), wherein the deposits can form a plurality of light-emitting layers in the organic light-emitting diode display panel . Compared with the existing fine metal mask, the mask 100 can help the plating material 11 moving toward the substrate to be plated 101 not along the normal line 31 to be deposited smoothly in the area of the substrate to be plated 101 exposed by the through hole 130, so as to help Reduce or avoid problems such as pixel color deficiency or pixel color distortion, thereby improving yield.

2A to 2D are schematic cross-sectional views of the manufacturing method of the mask in FIG. 1A . Referring to FIG. 2A , in the manufacturing method of the mask of this embodiment, first, a first photoresist layer 201 is formed on the conductive substrate 20 . Specifically, the conductive substrate 20 has a first plane 21 and a second plane 22 , wherein the first plane 21 is opposite to the second plane 22 . Taking FIG. 2A as an example, the first plane 21 and the second plane 22 may be opposite sides of the conductive substrate 20 , such as the upper surface and the lower surface, respectively. The first plane 21 may be the upper surface of the conductive substrate 20 , and the second plane 22 may be the lower surface of the conductive substrate 20 , wherein the first photoresist layer 201 is formed on the first plane 21 .

The first photoresist layer 201 partially covers the first plane 21 . In detail, the first photoresist layer 201 may have a plurality of openings H1 , and the openings H1 can expose part of the first plane 21 . Therefore, the first photoresist layer 201 partially covers the first plane 21 instead of completely covering it. The first photoresist layer 201 may be a patterned photoresist layer after exposure and development, and the conductive substrate 20 may be a metal plate, and the material thereof may be a single metal material or an alloy material. For example, the material of the conductive substrate 20 may be stainless steel. In addition, the openings H1 may be connected to each other to form mesh openings, and the first photoresist layer 201 will correspond to the through holes 130 of the mask 100 after subsequent completion.

Referring to FIGS. 2A and 2B , then, using the first photoresist layer 201 as a mask, the conductive substrate 20 is etched from the portion of the first plane 21 not covered by the first photoresist layer 201 to form a plurality of cavities 23 The master mold 200. Specifically, the master mold 200 includes a first plane 21 , a second plane 22 and an engraving pattern 230 , wherein the engraving pattern 230 has these cavities 23 and corresponds to the mask 100 after subsequent completion.

The depth D23 of each cavity 23 may be smaller than the thickness T20 between the first plane 21 and the second plane 22 . Therefore, these cavities 23 are not formed through the conductive substrate 20 (or the master mold 200 ). Taking FIG. 2B as an example, the cavities 23 may be exposed on the first plane 21 but not on the second plane 22 , so the engraved pattern 230 is exposed on the first plane 21 . In addition, in this embodiment, the method of etching the conductive substrate 20 may be wet etching. Therefore, these cavities 23 can be formed by isotropic etching, so that each cavity 23 has an inner concave curved surface 23c.

Referring to FIG. 2C , then, electroforming is performed on the master mold 200 to deposit metal material in each cavity 23 to form the mask 100 . Therefore, the mask 100 shown in FIG. 2C is formed of the deposited metal material, and is formed in the cavities 23 . It can be seen that the master mold 200 made of the conductive substrate 20 can be used to manufacture the mask 100 . In addition, during electroforming of the master mold 200 to form the mask 100 , the first photoresist layer 201 is retained to reduce or avoid deposition of metal materials on the first plane 21 .

Since the material of the mask 100 may include nickel and iron, the electroplating solution used in the above electroforming may include nickel ions and iron ions, wherein the aforementioned iron ions may include trivalent iron ions and divalent ferrous ions, wherein at least A sort of. In addition, the material of the mask 100 may include nickel and iron, and the material of the conductive substrate 20 may be stainless steel, so the materials of the mask 100 and the conductive substrate 20 may be different from each other.

The engraved pattern 230 corresponds to the mask 100 , wherein the outer convex wall surfaces 131 and the outer convex curved surfaces 121 of the mask 100 are respectively fitted with the inner concave curved surfaces 23 c . In other words, both the outer convex wall surface 131 and the outer convex curved surface 121 can completely contact the inner concave curved surface 23c. Therefore, the shape (eg, the radius of curvature) of both the outer convex wall surface 131 and the outer convex curved surface 121 can be determined by the inner concave curved surface 23c. In addition, since the cavity 23 can be formed by isotropic etching (eg, wet etching), the concave curved surface 23 c of the cavity 23 can be controlled by adjusting the rate and time of etching the conductive substrate 20 . In other words, the convex wall surface 131 and the convex curved surface 121 of the mask 100 can also be controlled by adjusting the rate and time of etching the conductive substrate 20 .

Referring to FIG. 2D , after electroforming the master mold 200 , the master mold 200 is removed, wherein the method of removing the master mold 200 may be peeling. For example, the worker can directly peel off the master mold 200 and the mask 100 by hand, thereby removing the master mold 200 . At this point, the mask 100 is substantially completed. In addition, before removing the master mold 200, the first photoresist layer 201 can be removed first, wherein the first photoresist layer 201 can be removed with a photoresist stripper.

Since the cavity 23 of the master mold 200 has an inner concave curved surface 23c, the mask 100 made of the master mold 200 can have an outer convex curved surface 121 and an outer convex wall surface 131, so that the mask 100 has a plurality of uneven widths. Through holes 130 . From this, it can be seen that the mask 100 made through the master mold 200 is favorable for evaporation, so that the plating material 11 that does not move along the normal line 31 can be smoothly deposited on the plated substrate 101 exposed by the mask 100 up (see Figure 1B), thereby improving yield.

3A to FIG. 3E are schematic cross-sectional views of a manufacturing method of a mask according to another embodiment of the present invention, wherein the manufacturing method of this embodiment is similar to the manufacturing method of the previous embodiment, so the following mainly describes this embodiment and the two previous embodiments. Differences between the two, and the same technical features and functions of the two are basically not repeated in description and illustration.

Please refer to FIG. 3A and FIG. 3B , in the manufacturing method of the mask of this embodiment, the first photoresist layer 201 is used as the mask to etch the conductive portion of the first plane 21 not covered by the first photoresist layer 201 After the substrate 20 (refer to FIG. 2A ), a master mold 200 having a plurality of cavities 23 is formed. Next, the first photoresist layer 201 is removed to expose the first plane 21, as shown in FIG. 3B.

Referring to FIG. 3C , after that, a second photoresist layer 202 is formed on the master mold 200 , wherein the second photoresist layer 202 covers the concave holes 23 and covers part of the concave curved surface 23 c . The second photoresist layer 202 has a plurality of plated openings 202h, and the plated openings 202h are respectively located in the concave holes 23 and respectively partially expose the concave curved surfaces 23c. Taking FIG. 3C as an example, the plating openings 202h may be formed on the bottoms of the cavities 23 one-to-one. The second photoresist layer 202 may be the same as the first photoresist layer 201 . That is to say, the second photoresist layer 202 may be a patterned photoresist layer after exposure and development, so the plating openings 202h may be formed by exposure and development.

Referring to FIG. 3D , then, electroforming is performed on the master mold 200 to deposit metal material in each cavity 23 to form the mask 300 . Therefore, the mask 300 shown in FIG. 3D is formed of the deposited metal material. The material of the mask 300 can be the same as the material of the mask 100 , so the electroplating solution used in electroforming can include nickel ions and iron ions (including at least one of trivalent iron ions and divalent ferrous ions). During electroforming of the master mold 200 , the second photoresist layer 202 is retained to reduce or avoid deposition of metal material on the first plane 21 . During electroforming, metal material extends into these plated openings 202h to form bumps 390 .

The mask 300 has the bumps 390 , and the bumps 390 can directly contact the concave curved surfaces 23 c of the cavities 23 respectively. However, other parts of the mask 300 will contact the second photoresist layer 202 and not contact the concave curved surface 23c. In other words, the second photoresist layer 202 is basically sandwiched between the mask 300 and the concave curved surfaces 23c, wherein the mask 300 can pass through the second photoresist layer 202 through the plating openings 202h.

Referring to FIG. 3E, after electroforming the master mold 200, the master mold 200 is removed. For example, the worker can directly peel off the master mold 200 and the mask 300 by hand to remove the master mold 200 . At this point, the mask 300 is basically completed. Additionally, after removing the master mold 200, the second photoresist layer 202 may be removed, where the second photoresist layer 202 may be removed with a photoresist stripper. After the second photoresist layer 202 is removed, only the bumps 390 of the mask 300 are connected to the master mold 200 , so that the mask 300 and the master mold 200 can be easily separated.

Mask 300 is similar to mask 100 previously described. Specifically, although the mask 300 is formed on the second photoresist layer 202 instead of being directly formed on the concave curved surface 23c of the cavity 23 , both the masks 300 and 100 have the same function, and have the same structure as In terms of shape, the mask 300 substantially also includes a first surface 110 , a second surface 120 and a plurality of through holes 130 . Secondly, since the material of the mask 300 can be the same as the material of the mask 100, the material of the mask 300 can also include nickel and iron, wherein the weight percentage of nickel in the mask 300 can be between 35 and 50%, and the weight of iron can be between 35 and 50%. The percentage can be between 50 and 65%.

From this, it can be seen that the masks 300 are similar to 100 . However, unlike the mask 100 , the mask 300 also includes the bumps 390 , wherein the bumps 390 are formed on the second face 120 . Taking FIG. 3E as an example, the bumps 390 are respectively formed on the convex curved surfaces 121 of the second surface 120 , and each of the bumps 390 protrudes from the convex curved surfaces 121 . For example, the bumps 390 may be protruded from the convex curved surfaces 121 one-to-one, as shown in FIG. 3E .

To sum up, using the inner concave curved surface of the above-mentioned master mold, a mask with an outer convex curved surface and an outer convex wall surface can be formed, wherein the width of each through hole of the mask is not uniform, so that the coating produced by evaporation The material can enter the through hole from the second side of the mask (with a plurality of convex curved surfaces), and is smoothly deposited on the plated substrate (eg glass plate) exposed by the through hole. Compared with the existing fine metal masks, the masks disclosed or taught in the above embodiments help to reduce or avoid problems such as pixel color deficiency or pixel color distortion, thereby improving the yield.

Although the present invention has been disclosed above by the embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the appended patent application.

10: Evaporation source 11: Plating 20: Conductive substrate 21: The first plane 22: Second plane 23: Dimples 23c: Concave surface 31: Normal 100, 300: Mask 101: Plated substrate 110: The first side 120: Second side 121: convex surface 130: Through hole 131: convex wall 200: master mold 201: First photoresist layer 202: Second photoresist layer 202h: Electroplating openings 230: Intaglio pattern 390: bump A13: Axis D23: Depth H1: Opening T20: Thickness W11, W12: width

1A is a schematic cross-sectional view of a mask according to at least one embodiment of the present invention. FIG. 1B is a schematic cross-sectional view of the metal mask in FIG. 1A applied to evaporation. 2A to 2D are schematic cross-sectional views of the manufacturing method of the mask in FIG. 1A . 3A to 3E are schematic cross-sectional views of a manufacturing method of a mask according to another embodiment of the present invention.

21: The first plane

22: Second plane

23: Dimples

23c: Concave surface

100:Mask

121: convex surface

131: convex wall

200: master mold

201: First photoresist layer

230: Intaglio pattern

Claims (14)

A mask that includes: a first side; a second surface, opposite to the first surface, and having a plurality of convex curved surfaces; and A plurality of through holes communicate with the first surface and the second surface, wherein each of the through holes has an outer convex wall surface, which is connected between the first surface and the second surface. The mask of claim 1, wherein each of the convex wall surfaces is not perpendicular to the first surface. The mask of claim 1, wherein the radius of curvature of each of the convex curved surfaces of the second surface is greater than the radius of curvature of the convex wall surface of each of the through holes. The mask of claim 1, further comprising: A plurality of convex blocks are respectively formed on the convex curved surfaces, wherein each of the convex blocks protrudes from the convex curved surface. The mask of claim 1, wherein the mask material comprises nickel and iron, the weight percentage of nickel in the mask is between 35 and 50%, and the weight percentage of iron in the mask is between 50 and 65%. between. A master mold for manufacturing the mask as claimed in claim 1, wherein the master mold is made of a conductive substrate, and includes: a first plane; a second plane, relative to the first plane; and An engraving pattern is exposed on the first plane, wherein the engraving pattern corresponds to the mask, the engraving pattern has a plurality of concave holes, and each of the concave holes has a concave curved surface. The master mold of claim 6, wherein the depth of each of the cavities is less than the thickness between the first plane and the second plane. The master mold of claim 6, wherein the material of the conductive substrate is stainless steel. A method for manufacturing a mask, comprising: forming a first photoresist layer on a conductive substrate, wherein the conductive substrate has a first plane and a second plane opposite to the first plane, and the first photoresist layer partially covers the first plane; Using the first photoresist layer as a mask, etching the conductive substrate from the portion of the first plane not covered by the first photoresist layer to form a master mold with a plurality of cavities; electroforming the master to deposit a metallic material in each of the pockets; and After electroforming of the master, the master is removed. The manufacturing method of the mask as claimed in claim 9, further comprising: removing the first photoresist layer after etching the conductive substrate from the portion of the first plane not covered by the first photoresist layer; After removing the first photoresist layer and before electroforming the master mold, a second photoresist layer is formed on the master mold, wherein the second photoresist layer covers the cavities and has A plurality of electroplating openings, and the electroplating openings are respectively located in the cavities. The method of manufacturing a mask as claimed in claim 10, wherein the second photoresist layer is retained during electroforming of the master mold. The manufacturing method of the mask according to claim 9, wherein the depth of each of the concavities is smaller than the thickness between the first plane and the second plane. The method for manufacturing a mask as claimed in claim 9, wherein the first photoresist layer is retained during electroforming of the master mold. The manufacturing method of the mask according to claim 9, wherein the method of etching the conductive substrate is wet etching.

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