WO2022092848A1

WO2022092848A1 - Deposition mask

Info

Publication number: WO2022092848A1
Application number: PCT/KR2021/015302
Authority: WO
Inventors: 권오섭; 곽병헌
Original assignee: 에이피에스홀딩스 주식회사
Priority date: 2020-10-30
Filing date: 2021-10-28
Publication date: 2022-05-05

Abstract

A deposition mask according to an embodiment of the present invention comprises: a pattern unit which has a first surface and a second surface, and is provided with a plurality of openings corresponding to pixels of an organic light-emitting device that is to be manufactured; and a mask main body including a peripheral portion surrounding the pattern unit, wherein some of the openings are each defined by a first opening provided in the first surface, a second opening provided in the second surface, and an inner side connecting the first opening and the second opening, and the inner side includes, in a cross-section, a first inner side which is partially curved.

Description

deposition mask

The present invention relates to a metal mask, and more particularly, to a deposition mask for manufacturing an organic light emitting device.

In a process of manufacturing an organic light emitting display, a process of depositing an organic material at a desired position by adhering a thin metal mask to a substrate to form a pixel is performed.

Here, the thin metal mask is manufactured in the form of a deposition metal mask stick having an opening for deposition therein and extending in one direction. A deposition mask is manufactured by providing a plurality of sticks and welding them to the frame.

An object of the present invention is to provide a deposition mask that minimizes defects due to shadows in a deposition process.

A deposition mask according to an embodiment of the present invention includes: a pattern portion having first and second surfaces and provided with a plurality of openings corresponding to pixels of an organic light emitting device to be manufactured; and a mask body including a peripheral portion surrounding the pattern portion, wherein a portion of the opening includes a first opening provided on the first surface and a second opening provided on the second surface, and the first opening and the second opening It is defined by the inner surface connecting the openings, and the cross section of the inner surface has a first inner side that is at least partially curved, and satisfies Equation 1 below.

[Equation 1]

Here, l is the shortest distance from a first line connecting both ends of the curve to a second line parallel to the line connecting both ends of the curve but in contact with the curve, h is the first line from the first surface It is the shortest distance to two sides.

In one embodiment of the present invention, at least one of the first and second surfaces extends along a first direction, and the angle between the first direction and the first line connecting both ends of the curve is 55 degrees or less. can

In an embodiment of the present invention, the curved side may have a concave shape.

In an embodiment of the present invention, an upper surface corresponding to the first surface may be provided between two adjacent openings among the openings.

In one embodiment of the present invention, the cross section of the inner surface may further have a second inner side connecting the second surface and one end of the curve.

In an embodiment of the present invention, an upper surface corresponding to the first surface may not be provided between two adjacent openings among the openings.

The present invention includes a deposition mask stick used for a deposition mask, and the deposition mask may further include grippers provided at both ends of the mask body.

The present invention provides a deposition mask in which shadow defects are minimized without reducing a gap between a substrate and a magnet for securing additional magnetic force in a deposition system.

1 illustrates a deposition apparatus for depositing an organic compound on an object using a deposition mask according to an embodiment of the present invention.

2 is a perspective view illustrating a deposition mask.

3 is a perspective view illustrating a deposition mask stick according to an embodiment of the present invention.

4 is a perspective view illustrating a state in which a deposition mask stick gripped by a clamp is disposed.

5 is a perspective view illustrating a deposition mask manufactured using a deposition mask stick according to an embodiment of the present invention.

6 is a perspective view schematically illustrating a pattern part in a deposition mask stick according to an embodiment of the present invention.

FIG. 7 is a plan view illustrating a part of FIG. 6 .

8 is a cross-sectional view taken along line A-A' of FIG. 7 ;

9 is a cross-sectional view illustrating a part of a pattern part according to an embodiment of the present invention, respectively, and shows a part of the pattern part shown in FIG. 8 .

10 is a photograph of a pattern portion when patterning is simply performed using a conventional etching method regardless of tapered bowing.

11 shows sidewalls of each opening when a deposition mask is formed using an etching method and a structure that can be substantially obtained by supplementing the sidewalls.

12 to 16 show an embodiment according to an embodiment of the present invention, and show an embodiment manufactured by controlling a tapered bowing value in a deposition mask.

Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

The present invention relates to a deposition mask used in a deposition process of an organic compound when manufacturing an organic EL (Electro Luminescence) or organic semiconductor device, and a deposition mask stick used in the deposition mask. However, the deposition mask and deposition mask stick according to an embodiment of the present invention are not limited to such applications, and may be used for various purposes as long as they do not conflict with the concept of the present invention.

Referring to FIG. 1 , the deposition apparatus may include a container 17 containing a deposition material 19 disposed in a chamber 13 , and a deposition mask 10 .

The chamber 13 may be provided with a vacuum inside, and in this case, an exhaust means such as a pump for discharging the inside of the air to the outside may be mounted. An object for vapor deposition, for example, a substrate 15 is provided in the chamber 13 .

The vessel 17 may be provided in the form of a crucible as containing a deposition material 19 such as an organic compound. Although only the container 17 is shown in the drawing, the container 17 may be equipped with a heater for easily depositing the deposition material 19 . The heater may vaporize the deposition material into the chamber 13 by heating the vessel.

The container 17 may be disposed to face the substrate 15 and may be open toward the object.

The deposition mask 10 may include a frame 11 and a plurality of deposition mask sticks 100 coupled to the frame 11 . Openings 113 through which the evaporated deposition material 19 can pass are formed in the deposition mask 10 . The deposition mask 10 is disposed in the deposition chamber 13 to face the substrate 15 , which is an object to which the deposition material 19 is attached, and is provided between the vessel 17 and the substrate 15 .

In one embodiment of the present invention, the deposition materials evaporated from the vessel are attached to the surface of the substrate through an opening in the deposition mask. Thereby, the deposition material can be deposited on the surface of the substrate in a pattern corresponding to the position of the opening of the deposition mask.

2 is a perspective view illustrating the deposition mask 10 .

Referring to FIG. 2 , the deposition mask includes a frame 11 and a plurality of deposition mask sticks 100 bonded to and fixed to the frame 11 .

The frame 11 may be provided as a rectangular metal frame 11 having an empty space therein when viewed in a plan view. For example, the frame 11 may include a pair of first sides parallel to each other and a pair of second sides parallel to each other. In this case, the first side and the second side may be disposed perpendicular to each other, and the first side may be a long side and the second side may be a short side. The frame 11 may be made of a metal material having high rigidity in order to minimize deformation due to heat or compressive force acting on the frame 11 . For example, it may be made of a metal such as stainless steel. The empty space inside corresponds to a portion on which an organic material or the like is to be subsequently deposited.

The deposition mask stick 100 according to an embodiment of the present invention is provided in the shape of a rod elongated in one direction. Hereinafter, a direction in which the deposition mask stick 100 extends is referred to as a longitudinal direction D1 , and a direction perpendicular to the longitudinal direction is referred to as a width direction D2 .

The deposition mask stick 100 may be sequentially disposed on the frame 11 in a direction parallel to one of a long side or a short side of the frame 11 , and each end is bonded to the frame. In this case, the bonding portion 130 of the deposition mask stick 100 is provided to correspond to an area overlapping the frame 11 . The bonding portion 130 is bonded to the frame 11 in a region overlapping the frame 11 through laser welding. The deposition mask stick 100 may be bonded to the frame 11 , and in the process of bonding the deposition mask stick 100 to the frame 11 , it is tensioned using a holding device such as a clamp (hereinafter referred to as a clamp). placed on the frame

Hereinafter, a deposition mask stick will be first described for convenience of description, and then, a method of manufacturing a deposition mask using a plurality of deposition mask sticks and a deposition mask manufactured according to the method will be described below.

Referring to FIG. 3 , the deposition mask stick 100 according to an embodiment of the present invention is provided in the shape of a rod elongated in one direction D1 .

The deposition mask stick 100 includes a mask body part 110 extending in one direction D1 and holding parts 120 provided at both ends of the mask body part 110 . In one embodiment of the present invention, the body portion 110 and the grip portion 120 may be provided integrally without being separated, and provided as a whole in the form of a thin plate.

In one embodiment of the present invention, the deposition mask stick 100 may be made of various materials, for example, it may be made of metal. The deposition mask stick 100 may be made of a metal whose deformation is minimized even in a process step such as an organic material deposition process, for example, a material having a low thermal expansion coefficient, for example, a metal having a low thermal expansion coefficient.

In one embodiment of the present invention, the thermal expansion coefficient of the deposition mask stick 100 is provided to be as low as possible, and it is preferably the same as, or substantially the same if not identical to, the thermal expansion coefficient of the object to be deposited. For example, when the object to be deposited corresponds to the substrate of the display device, the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the deposition mask may be at the same level.

A process of depositing a deposition material on a substrate is often performed at a high temperature in a chamber, and both the deposition mask and the substrate are heated during the deposition process. At this time, since the size of the deposition mask and the substrate may change according to the coefficient of thermal expansion, if there is a difference in the coefficient of thermal expansion between the deposition mask and the substrate, there may be a change in shape due to different dimensional changes, and as a result, on the substrate The deposition precision may decrease. However, as in an embodiment of the present invention, when the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the deposition mask are at the same level, the shape change due to the dimensional change is reduced or prevented as much as possible.

In one embodiment of the present invention, the metal having a low coefficient of thermal expansion may include nickel (Ni), cobalt (Co), a nickel alloy, a nickel-cobalt alloy, stainless steel (SUS), Invar, and the like. Invar is an alloy with a very small coefficient of thermal expansion by adding 32% to 40% by mass of nickel (Ni) to 60% by mass to 68% by mass of iron (Fe), for example, 36% by mass to nickel to 64% by mass of iron. It is used in machines that cause errors when the dimensions change due to temperature changes, such as mechanical or optical machine parts and watch parts.

In one embodiment of the present invention, when the temperature of the deposition mask or the substrate does not reach a high temperature in the deposition process, the coefficient of thermal expansion of the deposition mask and the coefficient of the substrate do not need to be set equal to those of the substrate, and various types of alloy materials may be used. can

The main body 110 has an elongated shape and may be provided in a rectangular shape, and a pattern portion 111 corresponding to a shape to be deposited and a peripheral portion 119 surrounding the pattern portion 111 are provided. A plurality of pattern portions 111 may be provided at predetermined intervals along the long side of the body portion. One pattern part 111 may correspond to a display area in a display device. In an embodiment of the present invention, a plurality of display areas may be formed simultaneously by providing a plurality of pattern portions 111 . However, of course, one pattern unit 111 may not correspond to one display area and a plurality of pattern units 111 may correspond to one display area.

In one embodiment of the present invention, the body portion 110 is further provided with a bonding portion 130 for bonding to the frame thereafter. The bonding portion 130 is provided at both ends of the body portion 110 , that is, a portion adjacent to the grip portion 120 . The position, area, and shape of the bonding part 130 may be variously changed according to the shape of the frame to be bonded thereafter.

The gripping part 120 is provided in an outward direction from both ends in the longitudinal direction D1 of the main body part 110 . The grip part 120 is a part gripped using a gripping tool such as a clamp when the mask stick needs to be gripped, such as by bonding the mask stick to a frame.

The gripping part 120 includes a first gripping part 120a provided on one side along the longitudinal direction D1 of the main body 110 and a second gripping part 120b provided on the other side.

The first and second

gripping parts

120a and 120b have the width of the main body 110 of the main body 110 and the width of the first and second

gripping parts

120a and 120b, depending on the embodiment, They may be the same as each other or they may be different from each other.

In the present embodiment, it will be described as an example that the widths of the first and second

gripping parts

120a and 120b are equal to each other along the longitudinal direction D1.

In one embodiment of the present invention, each of the first and second

gripping parts

120a and 120b has at least two blades 121 extending outward from the main body 110 . Two blades 121 are provided on the first gripping part 120a and may be respectively disposed at both ends in the width direction D2, but the present invention is not limited thereto. For example, three blades 121 may be provided in such a way that two of the blades 121 are disposed at both ends in the width direction D2 and one of the blades is disposed in the center of the width direction. The second gripper 120b may also be provided with two blades 121 , and three or more blades 121 may be provided according to an embodiment. In one embodiment of the present invention, when the gripping part 120 is gripped by a device such as a clamp, the first and second gripping parts 120a so that the tensile force acts equally from both sides of the main body 110 in the outward direction. , 120b) and the number of blades 121 may be symmetrical with respect to the center of the main body 110 .

In one embodiment of the present invention, the gripper 120 may have various shapes, and the shape of the blade 121 may also be variously modified according to the shape. For example, a concave portion RC recessed in the body portion 110 direction may be formed on the outer end side of the gripper 120 , and the concave portion RC may have a U-shape. In this case, the blade 121 may correspond to the upper end of the U-shape. In this case, each of the blades 121 may have the same width as it goes outward from the main body 110 , that is, in a direction away from the extension direction of the main body 110 , but may have a smaller width.

A deposition mask is manufactured by attaching a mask stick to a frame according to an embodiment of the present invention.

4 is a perspective view illustrating a state in which a deposition mask stick gripped by a clamp is disposed, and FIG. 5 is a perspective view illustrating a deposition mask manufactured using the deposition mask stick according to an embodiment of the present invention.

4 and 5 , in the method of manufacturing a mask using the deposition mask stick 100 according to an embodiment of the present invention, a metal sheet is first prepared, and the metal sheet is processed to form the deposition mask stick. After manufacturing, the deposition mask stick 100 is gripped with a clamp (CLP), the deposition mask stick 100 gripped with the clamp (CLP) is placed on the frame 11 , and the deposition mask stick 100 is placed on the frame After bonding to (11), it includes the step of removing the holding portion (120).

First, a method for manufacturing a deposition mask will be described.

In order to manufacture a deposition mask, a metal sheet is first manufactured. The metal sheet may be made of a metal having a small coefficient of thermal expansion as described above, or an alloy thereof. For example, the metal sheet may be manufactured using a rolled material of an iron alloy including nickel. The rolled material may have a thickness of 50 μm, or 30 μm or less, or less. The rolled material may be an alloy of nickel and iron, and may include various additional components such as cobalt and impurities.

In order to form a rolled material, a raw material constituting the rolled material is first prepared, and the raw material is pulverized as necessary and then melted in a melting furnace. The dissolution process may be performed by dissolving and mixing each raw material at a high temperature (eg, 1500 degrees or more) using gas discharge such as arc discharge. Through this dissolution process, a base material for a metal sheet can be obtained. According to an embodiment, the melting process may further include a process of adding aluminum, manganese, silicon, etc. to the melting furnace for deoxidation, dehydration, denitrification, and the like. In addition, the dissolution process may be performed in an atmosphere of an inert gas such as argon gas in a low pressure state lower than atmospheric pressure.

After the base material is taken out from the melting furnace, the grinding process may be performed. A film such as oxide of the base material may be removed through the grinding process. The grinding process may be performed in various ways such as grinding, sanding, and press-fitting, and through this, the thickness of the base material may be formed uniformly to some extent.

Next, the base material is manufactured into a metal sheet through a rolling process. The rolling process is performed using at least one rolling roll (for example, a pair of rolling rolls or one rolling roll and a rolling plate), and the thickness is reduced by rolling the base material by the rolling roll. Thereby, it is possible to obtain a metal sheet having a reduced thickness to a predetermined degree. The metal sheet may be wound around a core.

Here, the rolling process may include a hot rolling process, a cold rolling process, and the like. The hot rolling process processes the base material at a temperature higher than or equal to the temperature that changes the crystal arrangement of the ferrous alloy constituting the base material, and the cold rolling process processes the base material at a temperature below the temperature that changes the crystal arrangement of the ferrous alloy.

In a rolling process, the thickness and manufacturing speed of a metal sheet can be adjusted by adjusting the degree of pressure applied to a base material by a rolling roll, a rolling speed (for example, the conveyance speed of a metal sheet), the diameter of a rolling roll, etc.

After the rolling is performed, a process of removing the residual stress accumulated in the metal sheet by the rolling is performed. To this end, an annealing process for applying heat to the metal sheet is performed. The annealing process may be performed while pulling the metal sheet in the conveying direction (long side direction), and both batch type or continuous annealing is possible. By performing an annealing process, the metal sheet from which residual distortion was removed to some extent can be obtained. The annealing process may be set according to the thickness of the metal sheet or the pressure of the rolling roll, and for example, may be performed in a temperature range of 500° C. to 600° C. for about 30 seconds to 90 seconds. However, the temperature and time of the annealing process are not limited thereto and may be set to various temperatures according to the state of the metal sheet.

In one embodiment of the present invention, the annealing process may be performed in a non-reducing atmosphere or an inert gas atmosphere. The non-reducing atmosphere is an atmosphere that does not contain a reducing gas such as hydrogen, and the meaning of not containing a reducing gas means a case where the concentration of a reducing gas such as hydrogen is 10% or less. The inert gas atmosphere is an atmosphere in which the concentration of an inert gas such as argon gas, helium gas, or nitrogen gas is 90% or more. In one embodiment of the present invention, by performing the annealing process in a non-reducing atmosphere or an inert gas atmosphere, the formation of a nickel compound such as nickel hydroxide in the surface layer of the metal sheet can be suppressed.

In an embodiment of the present invention, a cleaning process for cleaning the metal sheet may be performed before the annealing process, and various kinds of cleaning liquids, for example, hydrocarbon-based cleaning liquids may be used.

In one embodiment of the present invention, the annealing process is also possible in a batch type or in a wound state.

Next, a slit process in which both ends in the width direction of the metal sheet obtained by the rolling process are cut over a predetermined range may be performed so that the width of the metal sheet after the annealing process may be within a predetermined range. The slit process is to remove cracks that may occur in the rolling process. To this end, a part of the metal sheet is cut out in the slit process.

In an embodiment of the present invention, at least two processes among the rolling process, the annealing process, and the slit process may be repeated a plurality of times, and the order may be partially changed if necessary. For example, the slit process may be performed before the annealing process.

The metal sheet produced in the above manner is sequentially conveyed by the conveying device to the processing device and then to the separating device. In the processing apparatus, a patterning process of processing a metal sheet to form an opening in a pattern portion and a cutting process of cutting the metal sheet with a deposition mask stick are performed. The patterning process is performed using an etching process using an etchant or a laser process. In one embodiment of the present invention, during the patterning process, the opening of the pattern part and the anti-slip pattern of the grip part may be formed in the same process by the same method. Alternatively, during the patterning process, the opening of the pattern part may be formed first, and the anti-slip pattern of the grip part may be formed later, or the reverse order may be used.

The cutting process may be performed using a laser, and a deposition mask stick is manufactured through this cutting process.

The plurality of deposition mask sticks 100 are bonded to and fixed to the frame 11 .

The deposition mask stick 100 is held by the clamp CLP and placed on the frame 11 . Here, the frame 11 may be provided with a size in which a plurality of deposition mask sticks 100 can be placed.

The clamp CLP has a shape capable of gripping the deposition mask stick 100 by contacting both surfaces of the deposition mask stick 100 , and is schematically shown in the drawings for convenience of description. The shape of the clamp CLP may be changed into various shapes within the scope of the inventive concept.

The gripper 120 is gripped by the clamp CLP, and a tensile force is applied in the longitudinal direction of the deposition mask stick 100 . In this case, a tensile force is applied in the longitudinal direction of the deposition mask stick 100 by the gripper 120 having a width wider than that of the main body 110 , and according to an embodiment, the tensile force may also act in the width direction. Accordingly, it is possible to suppress the generation of waves generated on the deposition mask stick 100 .

The deposition mask stick 100 is placed on the frame 11 sequentially in a direction parallel to one of the long side or the short side of the frame 11 in the above-described manner and then bonded. Here, the bonding portion 130 is bonded to the frame 11 in a state in which wave generation is minimized. In this case, the bonding portion 130 of the deposition mask stick 100 is provided to correspond to an area overlapping the frame 11 . The bonding portion 130 is bonded to the frame 11 in a region overlapping the frame 11 through laser welding.

During the welding process, the joint may be joined to the frame using a laser. When using a laser, the laser may be a YAG laser, and in this case, the spot diameter of the laser light may be 0.05 mm to 0.4 mm or less.

As the YAG laser device, a crystal obtained by adding Nd (neodymium) to YAG (yttrium aluminum garnet) can be used as an oscillation medium. In this case, the junction can be joined using harmonics generated by sequentially passing through a nonlinear optical crystal in addition to the fundamental wave generated by the YAG laser device. After the deposition mask stick 100 is bonded, the holding part 120 of each deposition mask stick 100 is removed.

Next, the holding part 120 is cut and removed. The holding part 120 may be removed at once after attaching all the necessary deposition mask sticks 100 to the frame 11 , but after bonding one deposition mask stick 100 , the holding parts 120 at both ends In the removal method, it may be removed every time the deposition mask stick 100 is bonded. In particular, since the width of the grip part 120 is wider than the width of the body part 110 , if it is not cut, it may interfere with other deposition mask sticks 100 , so after bonding one deposition mask stick 100 , The grip portion 120 may be removed, and then the deposition mask stick 100 may be bonded.

By bonding the plurality of deposition mask sticks 100 to the frame 11 in the above-described manner, a deposition mask including the plurality of deposition mask sticks 100 and the frame 11 is completed.

In one embodiment of the present invention, as the display device becomes larger and larger, it is not easy to manufacture a single deposition mask integrally formed, and a phenomenon of sagging due to its own weight may occur. To prevent this, after manufacturing a plurality of deposition mask sticks 100 , the mask is prevented from sagging by bonding to the frame 11 while applying a tensile force.

In this embodiment, a rod-shaped deposition mask stick 100 extending in one direction will be described as an example, but the present invention is not limited thereto. , is not limited to any one size, shape, or structure.

In the deposition mask stick and the deposition mask using the same according to an embodiment of the present invention, the pattern portion has a predetermined shape.

6 is a perspective view schematically illustrating a pattern part 111 in the deposition mask stick 100 according to an embodiment of the present invention. 7 is a plan view illustrating a part of FIG. 6 , and FIG. 8 is a cross-sectional view taken along line A-A' of FIG. 7 .

6 to 8 , the pattern part 111 may be provided in various shapes, but according to an exemplary embodiment of the present invention may have an approximately rectangular shape. However, the shape of the pattern part 111 is not limited thereto, and may have other shapes. For example, when the display device is provided in a circular shape, the shape of the pattern part 111 may also be provided in a circular shape.

The deposition mask stick 100 according to an embodiment of the present invention may include a plurality of openings 113 .

The shape to be deposited may vary depending on a target on which the deposition material is to be deposited. In an embodiment of the present invention, when an object on which a deposition material is to be deposited corresponds to a substrate of the display device, a shape to be deposited may be provided corresponding to the shape of the pixel PX. In this case, the pattern part 111 may have a plurality of openings 113 through which a deposition material is deposited, and the openings 113 may correspond to various sizes and positions of the pixels PX. For example, the plurality of openings 113 may be regularly arranged along rows and columns. The arrangement of the openings 113 may vary depending on an object to be deposited, and when the pixels PX are arranged along rows and columns, corresponding openings 113 may also be arranged along rows and columns. . In the arrangement of the openings 113 , the openings 113 may have a pitch substantially identical to the pitch of the pixel PX.

Here, if each pixel PX is for displaying a plurality of colors, the deposition material may be an organic material corresponding to the color of each pixel PX. For example, the deposition material may be a red organic light-emitting material, a green light-emitting material, and a blue light-emitting material. In this case, a mask corresponding to the pixel PX of each color may be provided differently, and each deposition material may be sequentially input to form a deposition material corresponding to the pixel PX of each color on the substrate.

In one embodiment of the present invention, when looking at the cross-section of the pattern portion 111, the opening 113 is provided in the form of penetrating the upper and lower surfaces of the metal sheet. The opening 113 may have various shapes according to a pattern forming method of the metal sheet. The opening 113 may be formed by etching using an etchant, using a laser, or by using electroplating. Each opening 113 may have a different cross-sectional view forming a side wall made according to a forming method. For example, the opening 113 may be formed by etching using an etchant, or may be formed using a laser.

Referring to FIG. 9 , the pattern part 111 may have a plurality of openings 113 through which a deposition material is deposited, and each of the openings 113 is a first opening provided on the first surface 111a of the metal sheet. 113a, a second opening 113b provided on a second surface 111b opposite to the first surface 111a of the metal sheet, and an inner connecting the first opening 113a and the second opening 113b It may include a side 115 . The second opening 113b may be provided on the second surface 111b opposite to the first surface 111a of the metal sheet, and may communicate with the first opening 113a opposite to the first surface 111a of the metal sheet. The first surface 111a of the metal sheet may be a surface on which a laser beam is irradiated and processing is started, and the second opening 113b is processed from the first surface 111a by a laser beam so that the laser beam is applied to the metal sheet. It may be a portion formed on the second surface 111b of the metal sheet while penetrating the metal sheet. In addition, the first opening 113a may be a portion through which a deposition material (or deposition gas) enters the opening 113 from an evaporation source, and the second opening 113b is a portion through which the deposition material is discharged from the opening 113 . can be part

The inner surface 115 may connect the first opening 113a and the second opening 113b, and the inclination angle ( or slope) may be determined. Here, the

inner surfaces

115 and 115 may connect the first surface 111a and the second surface 111b of the metal sheet to induce a flow of the deposition material in the opening 113 .

In an embodiment of the present invention, at least a portion of the cross-section of the inner surface 115 may be curved. For example, the cross-section of the inner surface 115 may be formed of a straight line, a curved line, or a curved line. In the drawing, a portion corresponding to a curve of the inner surface 115 is indicated as a first inner side 115a, and a portion corresponding to a straight line is indicated as a second inner side 115b. Here, in the case of the second inner side 115b, although shown as a straight line in the present embodiment, it may have a curved shape. In one embodiment of the present invention, the second inner side 115b may not be provided. That is, the second inner side 115b may be directly connected from the second surface 111b. In the following embodiments, an embodiment having the second inner side 115b will be described as an example.

In one embodiment of the present invention, the first inner side 115a may be provided in a concave shape. The first inner side 115a may have an arc shape having a constant curvature, and may be provided in a shape similar to an arc as a whole, but may have a different curvature depending on a location.

In an embodiment of the present invention, the first inner side 115a may satisfy Equation 1 below.

[Equation 1]

Here, a line connecting both ends of the curve is called a first line ( L1 ), and a line parallel to the first line ( L1 ) connecting both ends of the curve but in contact with the curve is called a second line ( L2 ). If, l corresponds to the shortest distance from the first line L1 to the second line L2 . (Hereinafter, the value of l is referred to as a tapering value.) h is the thickness from the first surface to the second surface, and h is the thickness of the final deposition mask after forming the opening. However, if the difference between the thickness before forming the opening and the thickness after forming the opening is not large, it may be substantially the same as the thickness of the deposition mask before forming the opening.

In an embodiment of the present invention, the first surface 111a or the second surface 111b may extend in a first direction, and a first line ( When the angle formed by L1 is referred to as the taper angle θ , the angle may be 70 degrees or less, for example, 55 degrees or less. In addition, the angle may be provided to be 45 degrees or more. When the angle of the first line L1 connecting the first direction and both ends of the curve is greater than 55 degrees, the inner wall has the effect of hindering the movement of the organic material during deposition of the organic material, and thus the shadow phenomenon may be severe. When the angle is 45 degrees or less, the volume of the mask may not be sufficient and it may be difficult to secure rigidity.

In an embodiment of the present invention, the first inner side 115a may be expressed by Equation 2 below.

[Equation 2]

In the above formula, a is the distance in the first direction from the point where the second line ( L2 ) and the curve are in contact with the second line ( L2 ) and the point where the curve is in contact with the foot of the water line, and h1 is the second line The height from the second surface 111b of the point where ( L2 ) and the curve meet, h2 is the height from the second surface 111b of the foot of the waterline.

In the deposition mask having the above structure, l may have an inverse relationship that decreases as the original thickness of the material for manufacturing the deposition mask decreases. Here, the value of l itself is positive, but the shape of the sidewall of the opening is a curve connecting the upper end and the lower end, that is, there may be cases in which the first line L1 is concave downward and convex in the upward direction. When the curve of the cross-section of the deposition mask is concave, the tapered bowing value is expressed as positive (+), and when it is convex in the upward direction, the tapered bowing value is defined as negative (-).

In one embodiment of the present invention, the tapered bowing value may be a value close to zero, and the closer to zero the better. In one embodiment of the present invention, the tapered bowing value may have a structure within a predetermined range, particularly, the tapered bowing value may be as close to zero as possible. However, the tapered bowing value should not be a negative value. If l is a negative value, the shadow may be deteriorated. In other words, according to an embodiment of the present invention, the shape of the opening of the deposition mask manufactured by the etching method (or other process) has a structure in which the tapered bowing value is close to or equal to 0, or the tapered bowing value is less than 0. provided at a large value.

In one embodiment of the present invention, in the first line ( L1 ), the position of the foot of the water line that is lowered from the point where the second line ( L2 ) and the curve are in contact may be to divide the first line ( L1 ) into equal parts. In the curve of the inner surface 115, if the distance from one upper end to the foot of the water line is k1 and the distance from the lower end to the foot of the water line is k2 , k1 and k2 may have the same value. . However, depending on the embodiment, k1 and k2 may be different from each other. However, if they are formed asymmetrically around the waterline's feet, it may affect the movement path of organic matter. Therefore, in the case of k1 and k2 , it is better to minimize the difference, and even if it is different, it is within 6:4~4:6. it is preferable

Here, the plurality of openings 113 may include one or more asymmetric openings 113 in which the inner surface 115 is symmetrically or asymmetrically inclined.

In the symmetric opening 113 , the inner surface 115 may be symmetrically inclined with respect to the center of the opening 113 , and the taper angles θ of the inner surfaces 115 facing each other may be the same.

In the asymmetric opening 113 , the inner surface 115 may be asymmetrically inclined, the inner surface 115 opposite to each other may be asymmetric, and the taper angle θ between the inner surfaces 115 opposite to each other is different from each other. can do. Through this, the inner surface 115 of either side can have a relatively gentle taper angle ( θ ) that can prevent or suppress the occurrence of shadows according to the difference in distance from the evaporation source, and does not participate in shadow generation. The inner surface 115 on the non-relatively inclined side may increase the volume of the metal mask by making the inclination relatively steep, and thus rigidity of the metal mask may be secured.

However, when the taper angle θ of the inner surface 115 is the same even between the plurality of openings 113, in the case of a fine metal mask for making a high-resolution panel of 500 pixels per inch (PPI) or more, the plurality of openings 113 The pitch between them is inevitably dense, and the processing overlaps, so that the thickness of the metal sheet may be reduced to 20 μm or less, and the rigidity of the metal mask may be reduced. As in one embodiment of the present invention, when the inner surface 115 taper angle θ of the opening 113 is manufactured asymmetrically, the inner surface 115 taper on the side closer to the evaporation source according to the distance difference from the evaporation source The angle θ can be gently adjusted, and the taper angle θ of the inner surface 115 of the other side can be adjusted relatively rapidly. As a result, it is possible to prevent or suppress the occurrence of shadows due to the difference in distance from the evaporation source, and at the same time, increase the volume of the metal mask to secure the rigidity of the metal mask. Accordingly, even in the high-resolution panel metal mask, the thickness of the metal sheet can be maintained at 20 μm or more, and the rigidity of the metal mask can be sufficiently secured.

Accordingly, in the deposition process, a deposition material such as an organic material is deposited on the target substrate through the opening 113 to form a thin film having a desired shape. The opening 113 may be provided in various ways according to the shape of the pixel to be formed. For example, the opening 113 may be rectangular in plan view. However, the shape of the opening 113 is not limited thereto, and may have various shapes including a circular shape.

According to an embodiment of the present invention, the opening 113 may be formed by various patterning methods. For example, the opening 113 may be formed using a dry and/or wet etching process, an electroplating process, a laser patterning process, or the like. In particular, in an embodiment of the present invention, the opening may be formed by laser patterning. In an embodiment of the present invention, the opening may also be manufactured by an etching method. In this case, the taper angle θ and the taper bowing value may be adjusted by adjusting the composition ratio of the etchant and the etching time.

In one embodiment of the present invention, the plurality of openings 113 may be regularly or irregularly formed in the pattern portion 111 to correspond to the pixels according to how the corresponding pixels are arranged.

The deposition mask according to an embodiment of the present invention is advantageous for deposition of organic materials when forming a high-resolution AMOLED panel, which will be described as follows. Currently, it is manufactured by the deposition mask stick etching method mainly applied to mass production, and the etching method appears as a shape having a large tapered bowing value when forming an opening due to an isotropic etching characteristic. Such a shape is inevitably more disadvantageous than the other cases in a stable deposition process, and in order to secure additional magnetic force, the distance between the target substrate (eg, LTPS substrate) to be deposited and the magnet plate must be reduced.

The magnetic force starts from the magnetization density ( M ), and is described by the magnetic dipole m and the unit volume V as in Equation 3 below.

[Equation 3]

Referring to Equation 3, the decrease in volume causes a decrease in magnetic force, which lowers the adhesion between the deposition mask and the target substrate. Reduces the magnetic force that can be flattened.

Therefore, due to the organic material incident at a specific angle, it is necessary to secure the taper angle below a certain angle. adversely affect

The present invention minimizes defects due to a decrease in magnetic force by controlling the tapered bowing to a minimum.

In an embodiment of the present invention, in the deposition mask according to an embodiment of the present invention, an upper surface corresponding to the first surface 111a may not be provided between two adjacent openings among the openings. That is, when the width of the upper surface corresponding to the first surface is d, the value of d may be 0.

10 is a photograph of a pattern portion when patterning is simply performed using a conventional etching method without regard to tapered bowing, and FIG. 11 is a sidewall of each opening when a deposition mask is formed using the etching method and complements it. Thus, the structure that can be practically obtained is shown together.

Referring to FIG. 10 , in the case of patterning using an etching method, a concave portion is formed according to an isotropic etching, and thus a tapered bowing value is displayed as a large value.

11 shows a shape of a sidewall in each opening when a deposition mask is formed using an etching method. The tapered bowing value is -, and in one embodiment of the present invention, the tapered bowing value is close to zero. A deposition mask can be formed by setting and reflecting such a tapered bowing value.

12 to 16 show an embodiment according to an embodiment of the present invention, and show an embodiment manufactured by controlling a tapered bowing value in a deposition mask. Each deposition mask was fabricated using a laser.

The photograph of FIG. 12 shows the result of forming the inner surface 115 by changing the settings of the left and right sides. In FIG. 12 , in the case of the left inner side, the bar has an upward convex shape, and the tapered bowing value is negative. On the other hand, in the case of the right inner side, the tapered bowing value was practically close to zero. When a deposition mask having such a shape is used, the shadow phenomenon on the left side appears strongly.

13A and 13B show the results of manufacturing in a form that satisfies Equation 1 and the taper angle for both left and right sides. However, in k1 and k2 , k2 > k1 , and the shadow phenomenon is relatively strong compared to the case where k1 and k2 have the same value.

15 and 16 are examples corresponding to the case where Equation 1 and the taper angle are satisfied and the taper bowing value is virtually zero. In the case of the present embodiment, a sufficient degree of magnetic force is exhibited and the shadow phenomenon is minimal.

When a deposition mask is manufactured using the deposition mask stick as described above, defects during organic material deposition are reduced by ensuring sufficient magnetic force, and shadows due to the pattern of the deposition mask are reduced. As a result, the yield of the deposition mask is ultimately increased.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art or those having ordinary skill in the art will not depart from the spirit and scope of the present invention described in the claims to be described later. It will be understood that various modifications and variations of the present invention can be made without departing from the scope of the present invention.

Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims

a pattern portion having first and second surfaces and provided with a plurality of openings corresponding to pixels of an organic light emitting device to be manufactured; and

It includes a mask body including a peripheral portion surrounding the pattern portion,

A portion of the opening is defined by a first opening provided on the first surface, a second opening provided on the second surface, and an inner surface connecting the first opening and the second opening, a cross-section of the inner surface has a first inner side that is at least partially curved,

A deposition mask stick satisfying Equation 1 below.

[Equation 1]

Here, l is the shortest distance from a first line connecting both ends of the curve to a second line parallel to the line connecting both ends of the curve but in contact with the curve, h is the first line from the first surface It is the shortest distance to two sides.
According to claim 1,

At least one of the first and second surfaces extends in a first direction, and an angle between the first direction and a first line connecting both ends of the curved line is 55 degrees or less.
3. The method of claim 2,

A deposition mask stick in which the curved side has a concave shape.
3. The method of claim 2,

A deposition mask stick having an upper surface corresponding to the first surface between two adjacent openings among the openings.
3. The method of claim 2,

The cross-section of the inner surface further has a second inner side connecting the second surface and one end of the curve.
3. The method of claim 2,

A deposition mask stick in which an upper surface corresponding to the first surface is not provided between two adjacent openings among the openings.
The deposition mask stick according to claim 1, further comprising grippers provided at both ends of the mask body.
A deposition mask having first and second surfaces and having a plurality of openings, the deposition mask comprising:

A portion of the opening is defined by a first opening provided on the first surface, a second opening provided on the second surface, and an inner surface connecting the first opening and the second opening, a cross-section of the inner surface has a first inner side that is at least partially curved,

A deposition mask satisfying Equation 1 below.

[Equation 1]

Here, l is the shortest distance from a first line connecting both ends of the curve to a second line parallel to the line connecting both ends of the curve but in contact with the curve, h is the first line from the first surface It is the shortest distance to two sides.
9. The method of claim 8,

At least one of the first and second surfaces extends along a first direction, and an angle between the first direction and a first line connecting both ends of the curved line is 45 to 55 degrees.
9. The method of claim 8,

A deposition mask in which the curved side has a concave shape.
9. The method of claim 8,

and an upper surface corresponding to the first surface is provided between two adjacent openings among the openings.
9. The method of claim 8,

The cross-section of the inner surface further has a second inner side connecting the second surface and one end of the curved line.
9. The method of claim 8,

A deposition mask in which an upper surface corresponding to the first surface is not provided between two adjacent openings among the openings.