TWI778581B - Mask for forming oled picture element and template for supporting mask and mask integrated frame - Google Patents

Abstract

The present invention relates to a mask for OLED pixel formation, a mask support template, and a frame-integrated mask. The mask according to the present invention is a mask formed with a plurality of mask patterns and used for forming OLED pixels. The mask pattern includes a first mask pattern on the upper part and a second mask pattern on the lower part. The thickness is greater than the thickness of the second mask pattern, the two sides of the first mask pattern have concave curvatures, the upper width of the first mask pattern is greater than the lower width of the second mask pattern, and the lower width of the first mask pattern smaller than the lower width of the second mask pattern.

Description

Mask for OLED pixel formation, mask support template, and frame-integrated mask

Field of Invention

The present invention relates to a mask for OLED pixel formation, a mask support template, and a frame-integrated mask. More specifically, it relates to a mask for forming an OLED pixel, a mask support template, and a frame-integrated mask capable of accurately controlling the size and position of a mask pattern.

Background of the Invention

As a technology for forming a pixel in an OLED (Organic Light Emitting Diode) manufacturing process, an FMM (Fine Metal Mask) method is mainly used, which tightens a metal mask (Shadow Mask) in the form of a thin film. Attach to the substrate and deposit organics on the desired locations.

A conventional mask manufacturing method prepares a metal sheet used as a mask, performs PR coating on the metal sheet, and then performs patterning, or performs PR coating to have a pattern, and then manufactures a patterned mask by etching. However, in order to prevent a shadow effect, it is difficult to form a tapered mask pattern obliquely, and an additional process needs to be performed, which leads to an increase in process time and cost, and a decrease in productivity.

In the ultra-high-definition OLED, the existing QHD image quality is 500-600PPI (pixel per inch, pixels per inch), and the pixel size reaches about 30-50μm, while 4KUHD and 8KUHD high-definition have higher than that Resolutions of -860PPI, -1600PPI, etc. Therefore, there is an urgent need to develop a mask that can precisely adjust the Die pattern size technique.

In addition, in the existing OLED manufacturing process, after the mask is manufactured into a strip shape, a plate shape, etc., the mask is welded and fixed to the OLED pixel deposition frame and used. To fabricate large area OLEDs, a plurality of masks can be fastened to the OLED pixel deposition frame, during which each mask is stretched to make it flat. In the process of fixing a plurality of masks on a frame, there is still a problem of poor alignment between masks and between mask units. In addition, in the process of welding and fixing the mask to the frame, the thickness of the mask film is too thin and the area is large, so there is a problem that the mask sags or twists due to the load.

In this way, considering the pixel size of ultra-high-quality OLEDs, it is necessary to reduce the alignment error between each unit to about a few μm. Exceeding this error will lead to defective products, so the yield may be extremely low. Therefore, it is necessary to develop a technique for preventing deformation such as sagging or twisting of the mask and for accurate alignment, a technique for fixing the mask to the frame, and the like.

Therefore, the present invention is proposed to solve the problems existing in the prior art as described above, and aims to provide an OLED pixel forming mask, mask support template and frame integrated type capable of accurately controlling the size of the mask pattern mask.

The object of the present invention is achieved by a mask for forming an OLED pixel formed with a plurality of mask patterns, the mask pattern includes a first mask pattern on the upper part and a second mask pattern on the lower part, and the thickness of the first mask pattern is greater than The thickness of the second mask pattern, the two sides of the first mask pattern have concave curvature, the upper width of the first mask pattern is larger than the lower width of the second mask pattern, and the lower width of the first mask pattern is smaller than the second mask pattern. The lower width of the mask pattern.

Both side surfaces of the second mask pattern may be formed to have convex curvatures.

The sum of the shapes of the first mask pattern and the second mask pattern may be tapered or inverted as a whole. Conical.

The angle formed by the imaginary straight line connecting the upper end corner of the first mask pattern to the lower end corner of the first mask pattern and the lower surface of the mask may exceed 0° and be smaller than 60°.

The lower width of the first mask pattern may be greater than 15.4 μm and less than 35 μm .

The thickness of the mask may be 5 μm to 20 μm .

Furthermore, the above objects of the present invention can be achieved by a template for supporting a mask for forming an OLED pixel, which includes: a template; a temporary adhesive portion formed on the template; and a mask bonded by interposing the temporary adhesive portion A plurality of mask patterns are formed on the template. The mask patterns include a first mask pattern on the upper part and a second mask pattern on the lower part. The thickness of the first mask pattern is greater than the thickness of the second mask pattern. Both sides of the mask pattern have concave curvatures, the upper width of the first mask pattern is larger than the lower width of the second mask pattern, and the lower width of the first mask pattern is smaller than the lower width of the second mask pattern.

A spacer insulating portion is also formed on the temporary bonding portion, and the mask can be bonded to the upper surface of the template by sandwiching the temporary bonding portion and the spacer insulating portion.

Both side surfaces of the second mask pattern may be formed to have convex curvatures.

The first mask pattern and the second mask pattern are formed by wet etching, and when the second mask pattern is wet-etched, the etchant is etched along the side surface of the exposed portion of the insulating portion of the separator, so that the second mask pattern can be etched. The lower width of the pattern is greater than the upper width.

Furthermore, the above objects of the present invention can be achieved by a frame-integrated mask integrally formed by a plurality of masks and a frame for supporting the masks, the frame including an edge frame portion having a hollow area; having a plurality of mask unit areas And connected to the mask unit sheet portion of the edge frame portion, each mask formed with a plurality of mask patterns is connected to the upper portion of the mask unit sheet portion, and the mask pattern includes the first mask pattern on the upper portion and the mask pattern on the lower portion. the second mask pattern, the thickness of the first mask pattern is greater than the thickness of the second mask pattern, the two side surfaces of the first mask pattern have concave curvature, and the upper width of the first mask pattern is greater than that of the second mask pattern The lower width of the first mask pattern is smaller than the lower width of the second mask pattern.

According to the present invention having the structure as described above, there is an effect that the size and position of the mask pattern can be precisely controlled.

23: Partition insulation part

25: Insulation part

50: Template

55: Temporary bonding part

100: Mask

110: Mask metal film

200: Frame

C: unit, mask unit

CR: Mask Cell Region

M1, M2, M3: The first, second, and third insulating parts

P: mask pattern

P1, P1-1, P1-2: first mask pattern

P2, P2-1, P2-2: Second mask pattern

SN: hole

WE1, WE2, WE3: Wet etching

FIG. 1 is a schematic diagram of the existing process of attaching a mask to a frame.

2 is a front view and a side cross-sectional view of a frame-integrated mask according to an embodiment of the present invention.

3 is a schematic diagram of a mask according to an embodiment of the present invention.

4 is a schematic diagram of a process of forming a mask by adhering a mask metal film on a template to fabricate a mask support template according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the etching degree of the mask according to the existing mask manufacturing process and the comparative example.

6 to 7 are schematic diagrams of a manufacturing process of a mask according to an embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating the etching degree of the mask metal film according to an embodiment of the present invention.

9 is a schematic diagram of a manufacturing process of a mask support template according to an embodiment of the present invention.

FIG. 10 is a schematic diagram of etching patterns of a mask metal film according to a comparative example and an embodiment of the present invention.

11 is a schematic diagram of a mask metal film according to an embodiment of the present invention.

FIG. 12 is a graph showing the relationship between pores and aperture ratios according to an experimental example of the present invention.

FIG. 13 is a schematic diagram of the process of manufacturing a mask following FIG. 11 .

FIG. 14 is a schematic diagram of a formation principle of a mask pattern according to an embodiment of the present invention.

15 is a schematic diagram of a mask according to an embodiment of the present invention.

16 to 18 are SEM photographs of a mask according to an experimental example of the present invention.

19 is a schematic diagram of a state in which a template is loaded on a frame so that a mask corresponds to a unit area of the frame according to an embodiment of the present invention.

FIG. 20 is a diagram of separating the mask and stencil after attaching the mask to the frame, according to an embodiment of the present invention. Schematic diagram of the separation process.

21 is a schematic diagram of a state in which a mask is attached to a cell region of a frame and an insulating portion is removed, according to an embodiment of the present invention.

Detailed ways

For the following detailed description of the present invention, reference may be made to the accompanying drawings which illustrate specific embodiments in which the present invention may be practiced. In order to enable those skilled in the art to implement the present invention, the embodiments are specifically described below. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice the invention. The various embodiments of the present invention should be understood to be mutually different but not mutually exclusive. For example, the specific shapes, structures, and characteristics described herein may enable one embodiment to be implemented into other embodiments without departing from the spirit and scope of the present invention. In addition, it should be understood that the position or arrangement of the individual constituent elements in each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Therefore, the following detailed description is not intended to limit the present invention, and the scope of the present invention is limited only by the scope of the appended claims and all equivalents thereof as long as it is properly described. Similar reference numerals in the drawings refer to the same or similar functions in various aspects, and for the sake of convenience, the length, area, thickness, etc. and their forms may also be exaggerated.

Hereinafter, in order to enable those skilled in the art to easily implement the present invention, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a conventional process of attaching a mask 10 to a frame 20 .

The existing mask 10 is a stick-type or a plate-type. The strip mask 10 in FIG. 1 can be used by welding and fixing both sides of the strip to the OLED pixel deposition frame. A body (Body, or mask film 11 ) of the mask 10 has a plurality of display cells C in it. One unit C corresponds to one display of a smartphone or the like. A pixel pattern P is formed in the cell C so as to correspond to each pixel of the display.

Referring to FIG. 1( a ), tensile forces F1 - F2 are applied along the long axis direction of the strip mask 10 , and the strip mask 10 is loaded on the frame-shaped frame 20 in the unfolded state. The size of the frame 20 can be It is sufficient for the cells C1-C6 of one strip mask 10 to be located in the blank area inside the frame, and it may also be sufficient for the cells C1 to C6 of a plurality of strip masks 10 to be located in the blank area inside the frame.

Referring to (b) of FIG. 1 , alignment is performed while finely adjusting the tensile forces F1 - F2 applied to each side of the bar mask 10 , and then the bar mask 10 is made by soldering a part of the side surface of the bar mask 10 . and the frame 20 are connected to each other. (c) of FIG. 1 shows a side section of the strip mask 10 and the frame connected to each other.

Despite fine-tuning the tensile forces F1-F2 applied to each side of the strip mask 10, the problem of poor alignment of the mask elements C1-C3 with each other still occurs. For example, the distances between the patterns P of the cells C1-C6 are different from each other or the patterns P are skewed. Since the stripe mask 10 has a large area including a plurality of cells C1 to C6 and has a very thin thickness of several tens of μm, it is easy to sag or twist due to a load. In addition, it is a very difficult operation to instantly confirm the alignment state of each of the cells C1-C6 through a microscope while adjusting the tensile force F1-F2 to make all the cells C1-C6 flat. However, in order to prevent the mask pattern P with a size of several μm to several tens of μm from adversely affecting the pixel process of the ultra-high-quality OLED, the alignment error is preferably not greater than 3 μm. The alignment error between such adjacent cells is referred to as pixel position accuracy (PPA).

Further, the strip masks 10 are respectively connected to a frame 20, and the alignment state between the strip masks 10 and between the cells C-C6 of the strip masks 10 is precisely Very difficult job, and only increases the alignment-based process time, which is a significant cause of reduced productivity.

In addition, after the strip mask 10 is connected and fixed to the frame 20 , the tensile forces F1 - F2 applied to the strip mask 10 act on the frame 20 in reverse as tension. This tension causes a slight deformation of the frame 20, and a problem in that the alignment state among the plurality of cells C-C6 is distorted occurs.

In view of this, the present invention proposes a frame 200 and a frame-integrated mask capable of forming an integrated structure of the mask 100 and the frame 200 . The mask 100 integrated with the frame 200 can not only prevent deformation such as sagging or twisting, but also can be accurately aligned with the frame 200 .

2 is a front view [ FIG. 2( a )] and a side sectional view [ FIG. 2( b )] of a frame-integrated mask according to an embodiment of the present invention.

Hereinafter, although this specification describes the arrangement of the frame-integrated mask, the structure and manufacturing process of the frame-integrated mask can be understood to include the entire contents of Korean Patent Application No. 2018-0016186.

Referring to FIG. 2 , the frame-integrated mask may include a plurality of masks 100 and a frame 200 . In other words, it is a form in which the plurality of masks 100 are attached to the frame 200, respectively. In the following, for the convenience of description, the square-shaped mask 100 is used as an example for description. However, before the mask 100 is attached to the frame 200, it may be a strip-shaped mask with protrusions for clamping on both sides and attached to the frame 200. The protrusions can be removed after application.

A plurality of mask patterns P are formed on each mask 100 , and one cell C may be formed on one mask 100 . One mask unit C can correspond to one display of a smartphone or the like.

The mask 100 may also be made of materials such as invar, super invar, nickel (Ni), and nickel-cobalt (Ni-Co). The mask 100 may use a metal sheet produced by a rolling process or electroforming.

The frame 200 may be formed in the form of attaching a plurality of masks 100 . In consideration of thermal deformation, the frame 200 is preferably formed of Invar, super Invar, nickel, nickel-cobalt, etc., which have the same thermal expansion coefficient as the mask. The frame 200 may include an edge frame portion 210 having a generally quadrangular, box-shaped shape. The inside of the edge frame part 210 may have a hollow shape.

In addition, the frame 200 has a plurality of mask unit regions CR, and may include a mask unit sheet portion 220 connected to the edge frame portion 210 . The mask unit sheet portion 220 may be composed of an edge sheet portion 221 and a first grid sheet portion 223 and a second grid sheet portion 225 . The edge sheet portion 221 , the first grid sheet portion 223 , and the second grid sheet portion 225 refer to respective portions divided on the same sheet, and these are integrally formed with each other.

The thickness of the edge frame portion 210 may be greater than the thickness of the mask unit sheet portion 220, and may be It is formed with a thickness of several mm to several cm. Although the thickness of the mask unit sheet portion 220 is thinner than that of the edge frame portion 210, it is thicker than the mask 100, and the thickness may be about 0.1 mm to 1 mm. The width of the first grid sheet portion 223 and the second grid sheet portion 225 may be about 1-5 mm.

In the planar sheet, a plurality of mask unit regions CR (CR11 to CR56) may be provided in addition to the regions occupied by the edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225. .

The mask 200 has a plurality of mask cell regions CR, and each mask 100 can be attached so that each mask cell C corresponds to each mask cell region CR, respectively. The mask unit C corresponds to the mask unit region CR of the frame 200, and part or all of the dummy portion may be attached to the frame 200 (mask unit sheet portion 220). Thus, the mask 100 and the frame 200 may form an integrated structure.

FIG. 3 is a schematic diagram of a mask 100 according to an embodiment of the present invention.

The mask 100 may include a mask cell C on which a plurality of mask patterns P are formed, and a dummy portion DM around the mask cell C. The mask 100 may be manufactured using a metal sheet produced by a rolling process, electroforming, or the like, and one cell C may be formed in the mask 100 . The dummy portion DM corresponds to the portion of the mask metal film 110 other than the cell C, and may include only the mask metal film 110 or may include the mask metal film 110 formed with a predetermined dummy portion pattern similar in shape to the mask pattern P. The dummy part DM corresponds to the edge of the mask 100 and part or all of the dummy part DM may be attached to the frame 200 (mask unit sheet part 220 ).

The width of the mask pattern P may be less than 40 μm , and the thickness of the mask 100 may be about 5-20 μm . Since the frame 200 has a plurality of mask cell regions CR ( CR11 to CR56 ), it may also have a plurality of masks including mask cells C ( C11 to 56 ) corresponding to the respective mask cell regions CR ( CR11 to CR56 ), respectively. Modulo 100. In addition, there may be a plurality of templates 50 for supporting a plurality of masks 100 described later, respectively.

4 is a schematic diagram of a process of forming a mask 100 by adhering a mask metal film 110 on a template 50 to fabricate a mask support template according to an embodiment of the present invention.

Referring to (a) of FIG. 4 , a template 50 (template) may be provided. Template 50 is a medium, one of The mask 100 is attached to the surface, and the mask 100 is moved while supporting the mask 100 . The center portion 50 a may correspond to the mask unit C of the mask metal film 110 , and the edge portion 50 b may correspond to the dummy portion DM of the mask metal film 110 . In order to support the mask metal film 110 as a whole, the template 50 is in the shape of a flat plate having an area larger than or equal to the mask metal film 110 .

The template 50 can use wafer, glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia. and other materials. As an example, the template 50 may use BOROFLOAT ^® 33, which is a borosilicate glass having excellent heat resistance, chemical resistance, mechanical strength, transparency, and the like. In addition, the thermal expansion coefficient of BOROFLOAT ^® 33 is about 3.3, which is not much different from that of the Invar mask metal film 110 , which has the advantage of being easy to control the mask metal film 110 .

In order to allow the laser beam L irradiated from the upper portion of the template 50 to reach the welding portion WP (area where welding is performed) of the mask 100 , the template 50 may be formed with a laser passing hole 51 . The laser passing holes 51 can be formed on the template 50 in a manner corresponding to the position and number of the welding portions WP. Since a plurality of welding portions WP are arranged at predetermined intervals on the edge of the mask 100 or on the dummy portion DM portion, a plurality of laser passing holes 51 may be formed at predetermined intervals accordingly. As an example, since a plurality of welding portions WP are arranged at predetermined intervals on the dummy portion DM portions on both sides (left/right) of the mask 100 , the laser passing holes 51 may also be located on both sides (left/right) of the template 50 . ) are formed in plural at predetermined intervals.

The positions and the number of the laser passing holes 51 do not necessarily correspond to the positions and the number of the welding portions WP. For example, only part of the laser passing holes 51 may be irradiated with the laser beam L to perform welding. In addition, the part of the laser passing hole 51 that does not correspond to the welding part WP can also be used as an alignment mark when aligning the mask 100 and the template 50 . If the material of the template 50 is transparent to the laser light L, the laser passing hole 51 may not be formed.

One side of the template 50 may form a temporary bonding portion 55 . Before the mask 100 is attached to the frame 200 , the temporary adhesive portion 55 can temporarily attach the mask 100 (or the mask metal film 110 ′) to one side of the template 50 and support it on the template 50 .

The temporary adhesive part 55 may use a heat-based detachable adhesive or an adhesive sheet and a UV-irradiated-based detachable adhesive or an adhesive sheet.

As an example, liquid wax may be used for the temporary adhesive portion 55 . As the liquid wax, the same wax used in the polishing step of the semiconductor wafer and the like can be used, and the type thereof is not particularly limited. As a resin component mainly used for controlling adhesion, impact resistance, etc. related to holding force, the liquid wax may include substances and solvents such as acrylic acid, vinyl acetate, nylon, and various polymers. As an example, acrylonitrile butadiene rubber (ABR) may be used as the resin component for the temporary adhesive portion 55 and SKYLIQUIDABR-4016 containing n-propanol may be used as the solvent component. The liquid wax may be formed on the temporary adhesive portion 55 by a spin coating method.

The temporary adhesive portion 55 serving as liquid wax decreases in viscosity at a temperature higher than 85° C. to 100° C., and increases in viscosity at a temperature lower than 85° C., and a part is cured into a solid, so that the mask metal film 110 can be solidified. 'Fixed with template 50.

Next, referring to (b) of FIG. 4 , the mask metal film 110 may be bonded on the template 50 . The liquid wax may be heated to above 85° C., and the mask metal film 110 is brought into contact with the template 50 , and then the mask metal film 110 and the template 50 are passed between rollers for bonding.

According to one embodiment, the template 50 is baked at about 120° C. for 60 seconds, so that the mask metal film lamination process can be performed immediately after the solvent of the temporary bonding portion 55 is vaporized. Lamination is performed by loading the mask metal film 110 on the template 50 with the temporary adhesive portion 55 formed on one side and passing it between an upper roll at about 100°C and a lower roll at about 0°C. As a result, the mask metal film 110 can be brought into contact with the template 50 by interposing the temporary adhesive portion 55 .

As yet another example, the temporary adhesive 55 may use thermal release tape. The thermal release tape can be a core film (Core Film) such as a PET film arranged in the middle, a thermal release adhesive layer (thermal release adhesive) is arranged on both sides of the core film, and a release film/release film is arranged for the outer contour of the adhesive layer. Morphology of the releasing film. Here, the adhesive layers disposed on both sides of the core film may have a phase different peelable temperatures from each other.

According to one embodiment, when the release film/release film is removed, the lower surface of the thermal release tape (the lower second adhesive layer of the core film) is adhered to the film 50, and the upper surface of the thermal release tape (the upper part of the core film) is adhered to the film 50. The second adhesive layer) may be adhered to the mask metal film 110'. The peeling temperatures of the first adhesive layer and the second adhesive layer are different from each other. Therefore, in FIG. 20 to be described later, when the template 50 is separated from the mask 100, as peelable heat is applied to the first adhesive layer, the mask 100 is removed. It can be separated from the template 50 and the temporary adhesive part 55 .

In addition, the mask metal film 110 may use a mask metal film whose one side or both sides are processed by a surface defect removal process and a thickness reduction process. The thickness of the mask metal film 110 may be about 5 μm to 20 μm . The surface defect removal process and the thickness reduction process may also be performed after the mask metal film 110 is adhered to the template 50 . In addition, the thickness reduction process may be performed only for the C portion of the mask unit. After a surface defect removal process such as CMP, an insulating portion (not shown) such as photoresist is formed only in the region corresponding to the welding portion WP of the mask metal film, or the mask metal film 110 is adhered and supported by the template 50 . In this state, after forming an insulating portion (not shown) such as photoresist only in the region corresponding to the welding portion WP of the mask metal film 110, an etching process for reducing the thickness is performed on the portion C of the mask unit, so that the welding portion is The WP is formed thick and has a level difference with the mask cell C, and at the same time, the surface of the mask cell C portion for forming the mask pattern P can be formed in a defect-free state.

Then, referring to (c) of FIG. 4 , the patterned insulating portion 25 may be formed on the mask metal film 110 . The insulating portion 25 may be formed of a photoresist material by a printing method or the like.

Next, etching of the mask metal film 110 may be performed. Methods such as dry etching, wet etching, etc. can be used, and are not particularly limited. As a result of the etching, portions of the mask metal film 110 exposed on the vacancies 26 between the insulating portions 25 are etched. The etched portion of the mask metal film 110 constitutes the mask pattern P, so that the mask 100 in which the plurality of mask patterns P are formed can be manufactured.

Then, referring to (d) of FIG. 4 , the manufacture of the template 50 supporting the mask 100 may be completed by removing the insulating portion 25 .

Next, the mask 100 will be fabricated by forming the mask pattern P on the mask metal film 110 process is explained.

5 is a schematic diagram of the etching degree (d) of the mask according to the conventional mask manufacturing process [(a) to (c)] and the comparative example.

Referring to FIG. 5 , only wet etching is performed in the manufacturing process of the existing mask.

First, as shown in FIG. 5( a ), a patterned photoresist M may be formed on a planar mask metal film 110 ′ (sheet). Then, as in (b) of FIG. 5 , wet etching WE may be performed through spaces between the patterned photoresists M. After performing the wet etching WE, part of the space of the mask metal film 110' is penetrated, so that the mask pattern P' can be formed. Then, if the photoresist M is cleaned, the mask metal film 110 ′ on which the mask pattern P′ is formed, that is, the mask 100 ′ can be produced.

As shown in FIG. 5( c ), the conventional mask 100 ′ has a problem that the size of the mask pattern P′ is not constant. Since the wet etching of WE is performed isotropically, the shape after etching is approximately an arc shape. Moreover, since it is difficult to keep the etching rate of each part consistent during the wet etching process of WE, the widths R1', R1", and R1"' of the penetration pattern after the penetrated mask metal film 110' can only be different from each other. In particular, in a pattern in which undercut UC (undercut) frequently occurs, not only the lower width R1" of the mask pattern P' is formed wider, but also the upper width R2" is formed wider, and undercutting occurs less frequently In the UC cut pattern, the lower widths R1', R1"' and the upper widths R2', R2"' are relatively narrow.

As a result, the conventional mask 100' has a problem that the size of each mask pattern P' is not uniform. As far as ultra-high-quality OLEDs are concerned, the current QHD quality is 500-600PPI (pixel per inch), and the pixel size reaches about 30-50μm, while 4KUHD and 8KUHD high-quality have higher -860PPI, - 1600PPI and other resolutions, so slight differences in size may cause product defects.

Referring to FIG. 5( d ), since the wet etching WE is performed isotropically, the shape after etching is approximately an arc shape. In addition, in the process of wet etching, the etching speed of each part is difficult to be completely the same. If only one wet etching is performed to penetrate the mask metal film 110 to form a mask pattern, the deviation will be greater. For example, although the wet etching rates of the mask pattern 111 and the mask pattern 112 are different, the upper width (the bottom cut) is not very different. However, the difference between the lower width PD1 of the mask metal film 110 penetrated by forming the mask pattern 111 and the lower width PD2 of the mask metal film 110 penetrated by forming the mask pattern 112 is much larger than the difference of the upper width. This is a result of the fact that wet etching proceeds isotropically. In other words, the widths that determine the pixel size are the lower widths PD1 and PD2 of the mask patterns 111 and 112, not the upper widths. Therefore, other wet etching methods different from one wet etching may be used to control the lower widths PD1, PD1, and PD2. Program for PD2.

Therefore, according to an aspect of the present invention, the precision of the mask pattern in the wet etching process can be improved by multiple wet etchings.

6 to 7 are schematic diagrams of a manufacturing process of a mask according to an embodiment of the present invention.

Referring to (a) of FIG. 6 , first, a mask metal film 110 as a metal sheet may be provided. The mask metal film 110 may be formed by a rolling process, electroforming, etc. The material of the mask metal film 110 may be invar, super invar, nickel (Ni), nickel-cobalt ( Ni-Co) etc.

Then, the patterned 2-1 insulating portion M1 may be formed on one surface (upper surface) of the mask metal film 110 . The 2-1 insulating portion M1 can be formed of a photoresist material by a printing method or the like. It should be noted that the insulating portions M1 , M2 , and M3 in FIGS. 6 to 7 correspond to the insulating portions 25 described later as insulating portions for forming the mask pattern P, and are different from the spacer insulating portions 23 .

The first insulating portion M1 may be a black matrix photoresist or a photoresist material with a metal plating film formed on the upper portion. In addition, the material of the first insulating portion M1 may be a photoresist material different from that of the second insulating portion M2 or the third insulating portion M3 described later, and may preferably be an epoxy-based photoresist material. The black matrix photoresist may be a material including resin black matrix, which is used to form the black matrix of the display panel. The shading effect of black matrix photoresist will be better than that of general photoresist. In addition, the photoresist with the metal plating film formed on the upper part has a better light-shielding effect of shielding the light irradiated from the upper part by the metal plating film. The first insulating part M1 may be a positive type photoresist material.

Then, referring to (b) of FIG. 6 , a first mask pattern P1 ′ of a predetermined depth may be formed on one side (upper surface) of the mask metal film 110 by wet etching WE1 . Although the first mask pattern P1 ′ is formed in a substantially circular arc shape without penetrating the mask metal film 110 , the first mask pattern (corresponding to the main etching pattern P1 - 2 ) in the present invention described with reference to FIG. 11 has Features include hole SN. For convenience of description, the hole portion is excluded from the description of FIG. 6 . That is, the depth value of the first mask pattern P1 ′ excluding the holes SN may be smaller than the thickness of the mask metal film 110 .

Due to the isotropic etching characteristics of the wet etching WE1, the width R2 of the first mask pattern P1 is different from the spacing R3 between the patterns of the first insulating portion M1, and may be larger than the spacing R3 between the patterns of the first insulating portion M1. wide width. In other words, since an undercut UC (undercut) is formed on the lower portions of both sides of the first insulating portion M1, the width R2 of the first mask pattern P1 ′ is compared with the interval R3 between the patterns of the first insulating portion M1 , which can be more than the width of the undercut UC.

Then, referring to FIG. 6( c ), the second insulating portion M2 may be formed on one surface (upper surface) of the mask metal film 110 . The second insulating portion M2 may be formed of a photoresist material by a printing method or the like. The second insulating portion M2 is preferably a positive-type photoresist material because it needs to remain on the space where the undercut UC is formed, which will be described later.

Since the second insulating portion M2 is formed on one side (upper surface) of the mask metal film 110 , a portion thereof is formed on the first insulating portion M1 , and the other portion is filled inside the first mask pattern P1 .

The second insulating portion M2 may use a photoresist diluted in a solvent. If a high-concentration photoresist solution is formed on the mask metal film 110 and the first insulating portion M1, the high-concentration photoresist solution reacts with the photoresist of the first insulating portion M1, thereby possibly causing the A part of the first insulating portion M1 is dissolved. Therefore, in order not to affect the first insulating portion M1, the second insulating portion M2 may use a photoresist whose concentration is reduced by diluting in a solvent.

Then, referring to (d) of FIG. 7 , a part of the second insulating portion M2 may be removed. As an example, a part of the second insulating portion M2 may be removed in the form of volatilization by baking. After the solvent of the second insulating portion M2 is volatilized by the baking process, only the photoresist component remains. Therefore, the second insulating portion M2' leaves a thinner portion, such as a coated film, on the exposed portion of the first mask pattern P1 and the surface of the first insulating portion M1. The thickness of the remaining second insulating portion M2 ′ is preferably less than several μm , so as not to affect the pattern width R3 of the first insulating portion M1 or the pattern width R2 of the first mask pattern P1 .

Then, referring to (e) of FIG. 7 , exposure L may be performed on one side (upper surface) of the mask metal film 110 . When exposure L is performed on the upper portion of the first insulating portion M1, the first insulating portion M1 may function as an exposure mask. Since the first insulating portion M1 is made of black matrix photoresist or a photoresist material with a metal plating film formed on the upper portion, the light shielding effect is excellent. Therefore, the second insulating portion M2 ″ [refer to FIG. 7( f )] located at the vertical lower portion of the first insulating portion M1 is not exposed L, and the other second insulating portions M2 ′ are exposed L.

Then, referring to (f) of FIG. 7 , if developing is performed after exposing L, the portion of the second insulating portion M2 ″ that has not been exposed to L is left, and other second insulating portions M2 ′ are removed. Since the second insulating portion M2 ′ is removed The part M2' is a positive type photoresist, so the part exposed to L will be removed. The remaining space of the second insulating part M2'' can be used to form an undercut UC at the lower part of both sides of the first insulating part M1 [refer to FIG. 6( b) the spatial correspondence of step].

Then, referring to (g) of FIG. 7 , wet etching WE2 may be performed on the first mask pattern P1 of the mask metal film 110 . The wet etching solution can penetrate into the space between the patterns of the first insulating portion M1 and the space of the first mask pattern P1 to perform wet etching WE2. The second mask pattern P2 may be formed through the mask metal film 110 . That is, it is formed by penetrating the other surface of the mask metal film 110 from the lower end of the first mask pattern P1.

At this time, the second insulating portion M2" is left on the first mask pattern P1. The remaining second insulating portion M2" may function as a mask for wet etching. That is, the second insulating portion M2″ masks the etchant and prevents the etchant from being etched toward the side surface of the first mask pattern P1, but etches toward the lower surface of the first mask pattern P1.

Since the second insulating portion M2" is arranged in the undercut UC space of the vertical lower portion of the first insulating portion M1, the pattern width of the second insulating portion M2" is substantially opposite to the pattern width R3 of the first insulating portion M1. answer. Thus, the second mask pattern P2 corresponds to wet etching WE2 for the interval R3 between the patterns of the first insulating portion M1. Therefore, the width R1 of the second mask pattern P2 may be smaller than the width R2 of the first mask pattern P1.

Since the width of the second mask pattern P2 defines the width of the pixel, the width of the second mask pattern P2 is preferably smaller than 35 μm . If the thickness of the second mask pattern P2 is too thick, it is difficult to control the width R1 of the second mask pattern P2, and the uniformity of the width R1 decreases, and the overall shape of the mask pattern P may not be tapered/inverted tapered , so the thickness of the second mask pattern P2 is preferably smaller than that of the first mask pattern P1. The thickness of the second mask pattern P2 is preferably close to 0, and when the size of the pixel is considered, for example, the thickness of the second mask pattern P2 is preferably about 0.5 to 3.0 μm , more preferably 0.5 to 2.0 μm .

The sum of the shapes of the connected first mask patterns P1 and the second mask patterns P2 may constitute a mask pattern P. FIG.

Then, referring to (h) of FIG. 7, the fabrication of the mask 100 may be completed by removing the first insulating portion M1 and the second insulating portion M2″. The first mask patterns P1, P2 include inclined faces, and the second mask The height of the pattern P2 is very low, so if the shapes of the first mask pattern P1 and the second mask pattern P2 are added up, the overall shape is a tapered shape or an inverted tapered shape.

In addition, between steps (b) and (c) of FIG. 6 , steps (b2) and (b3) may be performed.

Referring to (b2) of FIG. 6, a third insulating portion M3 may be formed in the first mask pattern P1'. A third insulating portion M3 may be formed on at least a portion of the first mask pattern P1 ′ exposed between the first insulating portions M1 . For example, the third insulating portion M3 having the width R3 may be formed in the interval between the patterns of the adjacent pair of the first insulating portions M1 , that is, on the first mask pattern P1 ′.

In order to facilitate exposure, the third insulating portion M3 preferably uses a negative type photoresist material. When the negative photoresist is filled in the first mask pattern P1' and the upper part is exposed, the first insulating portion M1 functions as an exposure mask relative to the third insulating portion M3, and only the The third insulating portion M3 is exposed between the patterns of the first insulating portion M1. At this time, as illustrated in FIG. 6( c ), a third edge portion M3 having a width R3 may be formed on the first mask pattern P1 ′.

Then, referring to (b3) of FIG. 6, the first mask pattern P1' may be further subjected to wet etching WE2. Since part of the first mask pattern P1 ′ is in a state where the third insulating portion M3 is formed, the first mask pattern P1 ′ is not further etched downward, but is etched in the lateral direction. Therefore, the width of the first mask pattern P1' may be greater than R2 (P1'->P1).

Specific reasons for performing steps (b2) and (b3) of FIG. 6 are as follows.

If steps (b2) and (b3) of FIG. 6 are omitted and the second mask pattern P2 is formed after the first mask pattern P1' is formed, it will result in difficulty in reducing the mask pattern P' (P1', P2) cone angle. Based on the characteristics of the isotropic etching process of the first mask pattern P1', it is difficult for the side surface to have a small angle (the angle formed by the horizontal plane and the side of the mask pattern), since the angle exceeds 60° or is close to vertical, even if the There are still cases where the angle exceeds 70° for both wet etchings. On the whole, only when the angle formed by the side surface of the mask pattern P and the horizontal plane is about 30° to 70°, the shadow effect (Shadow Effect) can be prevented. OLED pixels are formed uniformly.

In addition, in order to form the surface of the mask pattern P uniformly without being rough, the wet etching process needs to be performed in a short time. However, if the wet etching process is performed in a short time, it is difficult for the side angle of the first mask pattern P1' to form a small angle. Finally, if the time of the wet etching process is prolonged in order to make the side angle of the first mask pattern P1' form a small angle, the problems of rough surface and uneven shape of the mask pattern will occur.

Therefore, the third insulating portion M3 is further formed in the first mask pattern P1 ′ to prevent the lower portion of the first mask pattern P1 ′ from being etched, and the wet etching WE3 is further performed toward the side of the first mask pattern P1 ′. (P1'->P1) has the effect of reducing the angle (a1->a2) formed by the side surface of the first mask pattern P1 and the horizontal plane. Since the wet etching is performed twice to form the first mask pattern P1, each etching process does not need to last for a long time, so that the surface morphology of the mask pattern P can be uniformly formed.

After further wet etching WE3 and forming the first mask pattern P1 which reduces the angle a2 formed by the side surface and the horizontal plane, the third insulating portion M3 may be removed.

FIG. 8 is a schematic diagram of a mask metal film 110 according to an embodiment of the present invention.

The process up to (a) of FIG. 8 is the same as the process described in (a) to (b) of FIG. 6 . However, in FIG. 8( a ), the first mask pattern P1 - 1 and the first mask pattern P1 - 2 having different etching degrees in the wet etching WE1 of the first insulating portion M1 will be described in comparison.

Referring to FIG. 8( a ), even for the same wet etching WE1-1 and WE1-2, different etching processes will occur depending on the etching portion, such as the first mask pattern P1-1 and the first mask pattern shown in P1-2. The pattern width R2-1 of the first mask pattern P1-1 is smaller than the pattern width R2-2 of the first mask pattern P1-2, and the difference between the pattern widths R2-1 and R2-2 will affect the resolution of the pixels. bad influence.

Then, referring to FIG. 8( b ), it can be confirmed that after performing the processes described in FIG. 6( c ) to FIG. 7( f ), the vertical lower space of the first insulating portion M1 can be formed with the Insulation part M2"-1, M2"-2. Depending on the size of the undercut space at the lower portion of the first insulating portion M1, the formation size of each of the second insulating portions M2"-1 and M2"-2 will be different. Although the size of the second insulating portion M2"-1 is smaller than that of the second insulating portion M2"-2, the pattern widths of the second insulating portions M2"-1 and M2"-2 are the same. The pattern width R3 of each of the second insulating portions M2"-1, M2"-2 may be the same to correspond to the pattern width R3 of the first insulating portion M1.

Then, referring to FIG. 8( c ), the second insulating portions M2 ″- 1 and M2 ″- 2 are used as wet etching masks, respectively, and wet etching WE2 is performed, so that the mask metal film 110 can be penetrated. As a result, the deviation of the widths R1-1 and R1-2 of the formed second mask patterns P2-1 and P2-2 is significantly smaller than the widths R2-1 and R1-2 of the first mask patterns P1-1 and P1-2. Deviation of R2-2. This is because after the first wet etching is performed on the mask metal film 110 at the depths of the first mask patterns P1-1 and P1-2, the second wet etching is performed on the thickness of the remaining mask metal film 110. The reason is that the pattern widths of the second insulating portions M2"-1 and M2"-2 subjected to the second wet etching are substantially the same as the pattern widths of the first insulating portions M1 subjected to the first wet etching.

As described above, the mask manufacturing method of the present invention has the effect that the mask pattern P of the desired size can be formed by performing the wet etching a plurality of times. Specifically, with a portion of the second insulating portion M2″ remaining, the wet etching WE2 for forming the second mask pattern P2 is compared with the wet etching WE1, WE1 for forming the first mask pattern P1, WE2 will be performed with a thinner width and a thinner thickness, so it has the advantage of being easy to control the width R1 of the second mask pattern P2. On the other hand, since the inclined surface can be formed by wet etching, the mask pattern P that can prevent the shadow effect can be formed.

9 is a schematic diagram of a manufacturing process of a mask support template according to an embodiment of the present invention.

In the present invention, the forming process of the mask pattern P of FIGS. 6 to 7 may be performed after the mask metal film 110 is adhered to the template 50 . The processes of (a), (b), and (c) of FIG. 9 correspond to the processes of (b), (c), and (d) of FIG. 4 , and thus the description of the same parts will be omitted.

Referring to (a) of FIG. 9 , the mask metal film 110 may be bonded to the template by interposing the temporary bonding portion 55 . However, the etching solution should be prevented from entering the interface between the mask metal film 110 and the temporary bonding portion 55 to damage the temporary bonding portion 55/template 50 and cause etching errors of the mask pattern P. As a result, the mask metal film 110 can be adhered to the upper surface of the template 50 in a state where the spacer insulating portion 23 is formed on one surface of the mask metal film 110 . That is, the surface of the mask metal film 110 on which the spacer insulating portion 23 is formed may face the upper surface of the template 50 . The mask metal film 110 and the template 50 may be bonded to each other by sandwiching the spacer insulating portion 23 and the temporary bonding portion 55 .

The spacer insulating portion 23 can be formed on the mask metal film 110 by a printing method or the like from a photoresist material that is not etched by an etchant. In addition, in order to maintain a circular shape after multiple wet etching processes, the spacer insulating portion 23 may include at least any one of cured negative photoresist and epoxy resin-containing negative photoresist. As an example, epoxy resin-based SU-8 photoresist and black matrix photoresist are preferably used, so that the temporary adhesive portion 55 is baked and the second insulating portion M2 is baked (refer to (d) of FIG. 7 ) and the like are cured together.

Then, referring to (b) of FIG. 9 , the patterned insulating portion 25 may be formed on the mask metal film 110 . The insulating portion 25 corresponds to the insulating portion 25 of FIG. 5( d ), or may correspond to the insulating portions M1 , M2 and M3 of FIGS. 6 to 7 .

Next, etching of the mask metal film 110 may be performed. The mask pattern P may be formed using the etching method of FIG. 4(d) or the etching method of FIGS. 6 to 7 .

Then, referring to (c) of FIG. 9 , the manufacture of the template 50 supporting the mask 100 may be completed by removing the insulating portion 25 . A mask support template including mask 100/spacer insulation 23/temporary adhesive 55/template 50 can be fabricated.

Next, the reason for producing the mask support template further including the spacer insulating portion 23 will be described in more detail.

FIG. 10 is a schematic diagram illustrating the etching degree of the mask metal film according to the comparative example and an embodiment of the present invention.

As shown in FIGS. 6 to 7 , it is more advantageous to perform etching only on one side (eg, the upper side) of the mask metal film 110 . If etching is performed simultaneously on both sides, the thickness of the mask metal film 110 may be uneven, and it may be difficult to obtain the desired shape of the mask pattern P. Wet etching WE is performed on one side, and since the wet etching is performed multiple times, it is very important that the etchant does not leak to the other side (eg, underside) of the mask metal film 110 .

FIG. 10( a ) is a comparative example in which the mask metal film 110 is bonded to the template 50 by interposing the temporary bonding portion 55 without the spacer insulating portion 23 . As detailed in (g) of FIG. 7 , since the thickness of the first mask pattern P1 ( P1 - 1 , P1 - 2 ) is relatively thick and the width of the second mask pattern P2 defines the width of the pixel, the second mask The width of the pattern P2 is preferably close to 0 μm .

Therefore, although the first mask pattern P1 is preferably formed with the maximum depth, even for the same wet etching WE1-1 and WE1-2, the degree of etching varies depending on the etched position. For example, the first mask pattern P1 -1 is shown with the first mask pattern P1-2. Like the first mask pattern P1-2' on the right side of FIG. 10(a), etching WE1-2 to the extent of forming holes SN may occur.

In this case, the temporary adhesive portion 55 exposed at the lower portion may also be damaged (55->55') due to wet etching of WE1-2. In addition to the temporary bond 55', the template 50 is also damaged.

In addition, when the etchant enters between the interface between the damaged temporary adhesive portion 55 ′ and the mask metal film 110 , WE1 - 2 ′ will further etch the lower portion of the first mask pattern P1 , thereby increasing the size of the pattern. The problem of forming excessively large or locally amorphous defects.

Therefore, according to the present invention, by further interposing the spacer insulating portion 23 between the mask metal film 110 and the temporary adhesive portion 55, the first mask pattern P1 can be removed during the first wet etching WE1 (WE1-1, WE1-2). -2 is formed through the mask metal film 110 , and the etching liquid can also be prevented from entering the lower surface of the mask metal film 110 .

Since the spacer insulating portion 23 includes at least any one of cured negative photoresist, negative photoresist containing epoxy resin, and black matrix photoresist, even if the first wet etching WE1 process, the second The subsequent etching processes such as the second wet etching WE2 and the third wet etching WE3 can also withstand without being melted by the etching solution. Accordingly, even if the first mask pattern P1-2 penetrates the mask metal film 110, the width of the pattern is not enlarged, and there is an effect that the width of the 2-1 insulating portion M1 can be maintained.

11 is a schematic diagram of a mask metal film according to an embodiment of the present invention. Fig. 11(a) is a schematic plan view, and Fig. 11(b) is a schematic side sectional view of (a). In addition, although FIG. 11 shows the mask pattern P1 which forms a circular shape on the basis of a plane, the mask pattern P may be formed in various forms, such as a quadrangle and a polygon.

As shown in FIG. 10, the first mask pattern P1 (P1-1, P1-2) is preferably formed with the maximum depth, but it is very difficult to achieve only the minimum thickness by accurately controlling the etching speed of WE1-1, WE1-2 Not easy. Therefore, the present invention can perform etching WE1-2 to the extent of forming holes SN as the first mask pattern P1-2' on the right side of FIG. 11(a). Therefore, after the first wet etching WE1 (WE1-1, WE1-2) [FIG. 6(b) step] is completed, in the mask metal film 110, at least a part of the plurality of first mask patterns P1 may include The hole SN penetrates through the lower surface of the mask metal film 110 . Having the depth of the first mask pattern P1 at the time points before and after the formation of the hole SN can form the deepest effect. Even if the hole SN is formed, since the spacer insulating portion 23 is formed on the template 50, the leakage of the etching solution through the hole SN can be prevented.

Since the first mask pattern P1 is formed based on the first wet etching, it exhibits isotropic etching characteristics such that the width is narrowed from the upper surface to the lower surface of the mask metal film 110 , and the side surface may have a concave curvature. Since undercuts are formed on the lower portions of both sides of the first insulating portion M1, the upper width of the first mask pattern P1 may be greater than the spacing R3 between the patterns of the first insulating portion. Therefore, the lowermost hole SN of the first mask pattern P1 may be located within the interval between the first insulating portion M1 and the first insulating portion M1 adjacent thereto (or within the interval between patterns of the first insulating portion M1 ) area in the vertical direction. Considering the lower width of the final mask pattern P, the pitch between patterns of the first insulating part M1 may be set to about 20 μm to 30 μm .

However, if the size of the hole SN becomes too large, when the second insulating portion M2 is formed in the subsequent process and the second etching WE is performed, the etching object may not exist, so it is difficult to form the second insulating portion M2 having the required size and shape. Mask pattern P2. In addition, the etching solution WE1 - 2 ′ flowing through the large hole SN also affects the temporary bonding portion 55 of the template 50 and the separator insulating portion 23 . Therefore, it is necessary to control the size of the hole SN. Finally, if the upper width of the mask pattern P is set to about 40 μm and the lower width is set to about 25 μm , the width of the hole SN is preferably less than about 15.4 μm (over 0), more preferably less than about 15 μm (more than 0).

FIG. 12 is a graph showing the relationship between pores and aperture ratios according to an experimental example of the present invention. FIG. 12( a ) shows the aperture ratio with respect to the target size of the hole SN, and FIG. 12( b ) shows the maximum width of the hole SN with respect to the aperture ratio. Here, the aperture ratio can be understood to mean the area of the hole SN relative to the area of the first mask pattern P1 on the basis of the plane (surface of the mask metal film). The aperture ratio can be quantified by transmitting black and white images.

Referring to FIG. 12( a ), it can be seen that the width of the hole SN fluctuates significantly in the section where the hole SN starts to be formed (the aperture ratio exceeds 0). As described above in FIG. 5( d ), this is because the wet etching proceeds isotropically, so that the etching speed in the width direction (PD1->PD2) is greater than that of the downward etching. Therefore, it is necessary to stably set the aperture ratio before the width of the hole SN fluctuates.

Referring to FIG. 12( b ), it can be seen that the width of the hole SN abruptly changes in the range of the aperture ratio of 0 to 0.3%. Therefore, in order to set the maximum width of the hole SN to be about 15 μm , the aperture ratio may be 0 to 0.3%, and more preferably about 0 to 0.1%.

Referring back to FIG. 11 , the angle a formed by the first mask pattern P1 and the horizontal plane may exceed 0° and be less than 60°. From another viewpoint, the angle a formed by the imaginary straight line from the connection hole SN to the upper end corner of the first mask pattern P and the lower surface of the mask metal film 110 may exceed 0° and be smaller than 60°. To prevent shadow effects, the final mask The angle formed by the side surface of the mold pattern P and the horizontal plane should be about 30° to 70°, but if the second mask pattern P2 is further formed through the subsequent process, the angle a can be further increased, so the first mask pattern P1 (No. The angle a formed by a mask pattern P1) and the horizontal plane is preferably smaller than the above-mentioned angle.

FIG. 13 is a schematic diagram illustrating a process of manufacturing the mask 100 next to FIG. 11 .

Referring to FIG. 13( a ), after the first mask pattern P1 having the holes SN is formed, a second insulating portion M2 ″ may be formed on the side surface of the first mask pattern P1 [refer to FIG. 7( f )]. Next, Wet etching WE2 may be performed on the first mask pattern P1. The wet etching solution penetrates into the space between the patterns of the first insulating portion M1 and the space of the first mask pattern P1 to perform wet etching WE2. The second insulating portion M2 "Masking the etchant and preventing the etchant from being etched in the direction of the side surface of the first mask pattern P1, the etching is performed in the direction of the lower surface of the first mask pattern P1.

Referring to FIG. 13( b ), the second mask pattern P2 can be formed in the form of penetrating the mask metal film. That is, the second mask pattern P2 can be formed in a form larger than the width of the hole SN and penetrating from the lower end of the first mask pattern P1 to the other end of the mask metal film 110 .

At this time, the second mask pattern P2 can be formed in a form different from that described in the above-described FIGS. 7( g ) and ( h ) in which both side surfaces are formed with a concave curvature. Since the first mask pattern P has the holes SN and the lower part of the mask metal film 110 has the spacer insulating portion 23 , the shape of the second mask pattern P2 can appear as shown in the figure.

FIG. 14 is a schematic diagram of a mask pattern forming principle according to an embodiment of the present invention. The reason why the second mask pattern P2 appears as shown in FIG. 13(b) will be described below.

Referring to FIG. 14( a ), the etching solution penetrates between the second insulating portions M2 ″, and the local thickness of the mask metal film 110 exposed around the hole SN is very thin due to the formation of the hole SN. In addition, the thickness of the mask metal film 110 The exposed part has a smaller curvature and a more horizontal shape than the unexposed part. Thereby, the part around the hole SN is etched WE2' with a thinner thickness and removed first, and as the side of the removed part is exposed, the The side can be further etched. The wet etching is performed isotropically, and the etch rate in the width direction (or the side direction) is greater than the etching degree in the downward direction [similar to PD1->PD2 in Fig. 5(d)] can also be enough to work together.

On the other hand, referring to FIG. 14( b1 ), the second insulating portion M2 ″″ does not necessarily correspond to the vertical lower position of the first insulating portion M1 , and may be formed along the side surface of the first mask pattern P1 to a lower position. Location. When exposure L is performed in FIG. 7( e ), due to the depth of the first mask pattern P1 , at least the corner portion of the second insulating portion M2 ″′ exposed through the interval between the first insulating portions M1 cannot be exposed. . Therefore, the second insulating portion M2 ″ is formed closer to the lower portion due to this portion remaining. In addition, in order to control the size of the second mask pattern P2 more accurately, the second insulating portion M2 ″″ may be formed through targeted exposure and development.

Next, the part of the mask metal film 110 exposed from the space between the second insulating portions M2 ″″ formed at a lower position along the side surface of the first mask pattern P1 may be etched WE2 .

Referring to FIG. 14( b2 ), the mask metal film 110 of the vertical lower portion of the second insulating portion M2 ″″ may have an undercut shape due to isotropic etching. Since the gap between the second insulating portion M2 ″ and the spacer insulating portion 23 is small, more flow flows downward than the upper or middle portion of the mask metal film 110 located below the second insulating portion M2 ″″. etching solution. Therefore, the undercut of the mask metal film 110 located at the lower portion of the second insulating portion M2 ″″ does not exhibit a concave curvature but exhibits a convex curvature or a shape close to a straight line.

Of course, the principles of Fig. 14(a) or (b1) and (b2) are applicable.

15 is a schematic diagram of a mask according to an embodiment of the present invention.

15 , the mask pattern P includes an upper first mask pattern P1 and a lower second mask pattern P2, and the thickness of the first mask pattern P1 may be greater than that of the second mask pattern P2.

As a result of isotropic etching of the first mask pattern P1, concave curvatures are formed on both side surfaces. Both side surfaces of the second mask pattern P2 do not have concave curvature but may have a convex curvature or a shape close to a straight line.

Of course, the upper width D1 of the first mask pattern P1 is larger than the lower width D2 of the second mask pattern P2. Also, the lower width D3 of the first mask pattern P1 (or the upper width D3 of the second mask pattern P2 ) may be smaller than the lower width D2 of the second mask pattern P2 . In FIG. 11 , the width of the hole SN of the first mask pattern P1 is set to be less than 15.4 μm , and the lower width D2 of the second mask pattern P2 is set to be less than 35 μm , so the lower width D3 of the first mask pattern P1 ( Or the upper width D3) of the second mask pattern P2 is preferably larger than 15.4 μm and smaller than 35 μm . Therefore, the side cross-sectional shape of the mask pattern P may take a shape similar to that of water droplets dropped on the ground.

The angle ta formed by the imaginary line connecting the upper corner of the first mask pattern P1 to the lower corner of the first mask pattern P1 and the lower surface of the mask may exceed 0° and less than 60°, preferably less than 55°. Since both side surfaces of the second mask pattern P2 have convex curvatures, the imaginary straight lines should be arranged to contact the lower end corner of the first mask pattern P1 instead of the lower end corner of the second mask pattern P2. Thereby, the shape of the mask pattern P, which is the sum of the shapes of the first mask pattern P1 and the second mask pattern P2, can be tapered or reverse tapered as a whole.

16 to 18 are SEM photographs of a mask according to an experimental example of the present invention. Figures 16 and 17 respectively show (1) a plane, (2) a milling line, (3) a side section along the milling line, and (4) an enlarged photo of the side section, and Figure 18 shows Enlarged photo of side section. The mask pattern P is formed into a circular shape on the basis of a plane.

Table 1 below shows the test data of mask thickness, taper angle ta, and height of left/right sills of various styles. The heights of the left/right sills correspond to t2' and t1' shown in FIG. 15, respectively. Samples 1 and 2 are representatively shown in FIGS. 16 and 17 , and samples 3 to 6 are shown in FIG. 18 .

Referring to FIGS. 16 to 18 , it can be observed that the mask pattern P as shown in FIG. 15 has a concave curvature on both sides of the first mask pattern P1, and a convex curvature or close to the two sides of the second mask pattern P2. straight line form. In addition, referring to Table 1, it can be seen that the height of the sill tends to decrease as the mask thickness becomes thinner. The taper angle is less than 55°. Compared with the mask thickness, the height of the sill is 6%, 22.8%, 26.7%, 25.6%, 27.9%, and 18.4%, and the maximum is not more than 30%.

Next, the process of adhering the mask 100 to the frame 200 using the manufactured mask support template 50 will be described.

19 is a schematic diagram of a state in which the template 50 is loaded on the frame 200 and the mask 100 is mapped to the unit region CR of the frame 200 according to an embodiment of the present invention. FIG. 12 illustrates the case where one mask 100 is mapped/attached to the cell region CR, but multiple masks 100 may be simultaneously mapped to all the cell regions CR so that the masks 100 are attached to the frame 200 . In this case, there may be a plurality of templates 50 for supporting the plurality of masks 100, respectively.

Template 50 can be transferred by vacuum chuck 90 . The surface opposite to the surface to which the template 50 of the mask 100 is adhered can be sucked and transferred by the vacuum chuck 90 . After the vacuum chuck 90 sucks the template 50 and turns it over, the process of transferring the template 50 to the frame 200 will not affect the bonding state and alignment state of the mask 100 .

Then, referring to FIG. 19 , the mask 100 may be corresponded to one mask unit region CR of the frame 200 . The correspondence between the mask 100 and the mask unit region CR can be achieved by loading the template 50 on the frame 200 (or the mask unit sheet portion 220 ). Whether the mask 100 corresponds to the mask unit region CR can be observed through a microscope while controlling the position of the template 50/vacuum chuck 90 . Since the template 50 presses the mask 100, the mask 100 and the frame 200 can be closely abutted.

In addition, the lower part of the frame 200 may be further arranged with a lower support body 70 . The lower supporter 70 may press the opposite surface of the mask cell region CR in contact with the mask 100 . At the same time, since the lower support body 70 and the template 50 press the edge of the mask 100 and the frame 200 (or the mask unit sheet part 220 ) in opposite directions to each other, the alignment state of the mask 100 can be maintained without be disrupted.

Next, the mask 100 may be irradiated with the laser L and attached to the frame 200 based on laser welding. The solder bead WB is generated in the soldered portion of the mask that is laser soldered, and the solder bead WB may have The same material as the mask 100/frame 200 and connected integrally with the mask 100/frame 200.

20 is a schematic diagram of a process of separating the mask 100 from the template 50 after attaching the mask 100 to the frame 200 according to an embodiment of the present invention.

20, after the mask 100 is attached to the frame 200, the mask 100 and the template 50 may be debonded. The mask 100 and the template 50 can be separated by at least one of heating ET, chemical treatment CM, application of ultrasonic waves US, and application of ultraviolet UV to the temporary adhesive portion 55 . Since the mask 100 remains attached to the frame 200, only the template 50 can be lifted. As an example, if thermal ET at a temperature higher than 85° C. to 100° C. is applied, the viscosity of the temporary adhesive portion 55 is reduced, and the adhesive force between the mask 100 and the template 50 is weakened, so that the mask 100 and the template 50 can be separated. As another example, the mask 100 may be separated from the template 50 by immersing the temporary bond 55 in a chemical such as IPA, acetone, ethanol, etc. to dissolve, remove, or the like. As another example, the adhesive force between the mask 100 and the template 50 is weakened by applying ultrasonic waves US or ultraviolet UV, so that the mask 100 and the template 50 can be separated.

21 is a schematic diagram of a state in which the mask 100 is attached to the frame 200 and the insulating portion 23 is removed, according to an embodiment of the present invention. FIG. 21 shows a state in which all the masks 100 are attached to the cell region CR of the frame 200 . Although the masks 100 may be attached one by one and then the templates 50 may be separated, all the masks 100 may be attached and then all the templates 50 may be separated.

The template 50 is separated from the mask 100 by the vacuum chuck 90 , and the spacer insulating portion 23 remains on the mask 100 . If the spacer insulating portion 23 is a cured photoresist, it is difficult to remove by a wet etching process. Therefore, in order to remove the spacer insulating portion 23 on the mask 100, at least one of plasma PS and ultraviolet UV may be applied. A process of removing only the spacer insulating portion 23 by applying atmospheric pressure plasma or vacuum plasma PS or ultraviolet UV after loading the frame-integrated masks 100 and 200 in another chamber (not shown) may be performed.

As described above, in the present invention, the first mask pattern P1 can be formed with the maximum depth and the sills can be left with the thinnest thickness, so that the scale can be controlled more precisely when the mask pattern P is finally formed. size and location. In addition, by using the mask support template including the mask metal film 110/spacer insulating portion 23/temporary adhesive portion 55/template 50, there is an effect that errors due to penetration/leakage of the etching solution in the wet etching process can be prevented .

As described above, although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited by the embodiments, and those of ordinary skill in the technical field to which the present invention pertains can refer to the embodiments without departing from the spirit of the present invention. Various deformations and changes are made. The modified examples and modified examples should be regarded as belonging to the scope of the present invention and the appended claims.

110: Mask metal film

D1: Upper width

D2, D3: lower width

P: mask pattern

P1: first mask pattern

P2: Second mask pattern

ta: angle

Claims (9)

A mask is formed with a plurality of mask patterns and used to form OLED pixels, wherein the mask pattern includes a first mask pattern on the upper part and a second mask pattern on the lower part, and the thickness of the first mask pattern is greater than the thickness of the second mask pattern, the upper width of the first mask pattern is greater than the lower width of the second mask pattern, the lower width of the first mask pattern is smaller than the lower width of the second mask pattern, the first mask pattern Both sides of the second mask pattern have a concave curvature, and both sides of the second mask pattern have a convex curvature. The mask according to claim 1, wherein the first mask pattern and the second mask pattern are formed by wet etching in the same direction, and the etching solution is further processed in the lateral direction below the second mask pattern etching. The mask according to claim 1, wherein the angle formed by the imaginary straight line connecting the upper end corner of the first mask pattern to the lower end corner of the first mask pattern and the lower surface of the mask exceeds 0° and is smaller than 60° °. The mask of claim 1, wherein a lower width of the first mask pattern is greater than 15.4 μm and less than 35 μm . The mask of claim 1, wherein the thickness of the mask is 5 μm to 20 μm . A mask support template for supporting a mask for forming an OLED pixel, the mask support template comprising: a template; a temporary adhesive portion formed on the template; and a mask bonded to the template by sandwiching the temporary adhesive portion A plurality of mask patterns are formed on the template, the mask patterns include a first mask pattern on the upper part and a second mask pattern on the lower part, the thickness of the first mask pattern is greater than that of the second mask pattern, and the first mask pattern is thicker than the second mask pattern. The upper width of the die pattern is larger than that of the second mask pattern The lower width of the first mask pattern is smaller than the lower width of the second mask pattern, both sides of the first mask pattern have concave curvature, and both sides of the second mask pattern have convex curvature. The mask support template according to claim 6, wherein a spacer insulating portion is further formed on the temporary bonding portion, and the mask is bonded to the upper surface of the template by sandwiching the temporary bonding portion and the spacer insulating portion. The mask support template according to claim 7, wherein the first mask pattern and the second mask pattern are formed by wet etching, and when the second mask pattern is wet-etched, the etchant is exposed on the insulating portion of the separator. Part of the etching is performed along the side direction, so that the width of the lower portion of the second mask pattern is larger than the width of the upper portion. A frame-integrated mask, which is integrally formed by a plurality of masks and a frame for supporting the masks, wherein the frame includes: an edge frame portion including a hollow area; a mask unit sheet portion having a plurality of masks The mold unit area is connected to the edge frame portion; each mask formed with a plurality of mask patterns is connected to the upper portion of the mask unit sheet portion, and the mask pattern includes a first mask pattern on the upper portion and a second mask on the lower portion. pattern, the thickness of the first mask pattern is greater than the thickness of the second mask pattern, the upper width of the first mask pattern is greater than the lower width of the second mask pattern, and the lower width of the first mask pattern is smaller than the second mask pattern The lower width of the first mask pattern has a concave curvature on both sides, and the second mask pattern has a convex curvature on both sides.

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