Method for manufacturing film formation mask
阅读说明：本技术 成膜掩模的制造方法 (Method for manufacturing film formation mask ) 是由 崎尾进 岸本克彦 于 2019-04-01 设计创作，主要内容包括：一种成膜掩模的制造方法,该成膜掩模具有在以拉伸在框架上的状态固定的掩模基材的有源区域形成部排列成矩阵状的多个开口部,包括：工序A,准备初始状态的掩模基材,初始状态的掩模基材以规定的条件被拉伸的状态下固定于框架,使得能够规定xy面；工序B,准备所确定的多个开口部的每一个在xy面中的位置的目标坐标数据；工序C：对多个开口部的每一个,预测由于形成开口部而产生的从目标坐标数据开始的位移量,生成减去位移量的校正数据；以及工序D：在基于目标坐标数据和校正数据确定的位置形成多个开口部的每一个；在工序C中关于多个开口部的每一个的校正数据与形成多个开口部的顺序相关联,且在工序D中多个开口部按照顺序形成。(A method for manufacturing a film formation mask having a plurality of openings arranged in a matrix in active region forming portions of a mask base material fixed in a stretched state on a frame, comprising: a step (A) of preparing a mask base material in an initial state, the mask base material in the initial state being fixed to a frame in a state of being stretched under a predetermined condition so that an xy plane can be defined; a step B of preparing target coordinate data of the position of each of the plurality of openings specified in the xy plane; and a step C: predicting a displacement amount from the target coordinate data, which is caused by forming the opening portion, for each of the plurality of opening portions, and generating correction data by subtracting the displacement amount; and a step D: forming each of a plurality of openings at a position determined based on the target coordinate data and the correction data; the correction data for each of the plurality of openings in step C is associated with the order in which the plurality of openings are formed, and the plurality of openings are formed in order in step D.)
1. A method for manufacturing a film formation mask, the film formation mask comprising: a frame; a mask base material fixed to the frame in a stretched state; and a plurality of openings provided in the active region forming portion of the mask base material and arranged in a matrix having m rows and n columns, the method for manufacturing a film formation mask comprising:
a step (A) of preparing a mask base material in an initial state, which is fixed to the frame in a stretched state under a predetermined condition so that an xy plane can be defined;
a step B of preparing target coordinate data of the positions of the plurality of openings specified in the xy plane;
a step C of predicting a displacement amount of each of the plurality of openings, which is displaced from the target coordinate data due to the formation of the opening, and generating correction data for reducing the displacement amount; and
a step D of forming each of the plurality of openings at a position specified based on the target coordinate data and the correction data,
in the step C, the correction data for each of the plurality of openings is associated with an order of forming the plurality of openings, and
in the step D, the plurality of openings are formed in the stated order.
2. The method of manufacturing a film-forming mask according to claim 1, wherein the step C includes a step CS of obtaining a strain distribution of the entire mask base material when forming the openings in accordance with an order of forming the plurality of openings by simulation using a finite element method, predicting a displacement amount of each of the plurality of openings based on the strain distribution, and generating the correction data,
the step CS includes:
a step CS1 of obtaining a displacement D1(k) of a position on the mask base material where a k-th opening is to be formed, based on a strain distribution of the entire mask base material immediately before the k-th opening is formed;
a step CS2 of obtaining a displacement D2(k) of a position on the mask base material where a k-th opening is to be formed, based on a strain distribution of the entire mask base material after all of the plurality of openings are formed; and
in the step CS3, the correction data c (k) of the k-th opening is obtained from D1(k) and D2 (k).
3. The method of claim 2In the step CS, an initial parameter for obtaining a strain distribution of the entire mask base material in the initial state is provided in advance, and the initial parameter is young's modulus Yx0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0。
4. The manufacturing method according to claim 2, wherein the step C includes at least Lz of initial parameters for obtaining a strain distribution of the entire mask base material in the initial state in the step CS0Procedure CSP of distribution in xy plane, the initial parameter being Young's modulus Yx0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0，
The process CSP further comprises: a CSP1 step of obtaining, by simulation using a finite element method, a strain distribution of the entire mask base material when a plurality of recesses having a depth d of 40% or less of the thickness of the mask base material are formed so as to correspond to each of the plurality of openings in the order in which the plurality of openings are formed;
a step CSP2 of measuring the positions of the plurality of formed recesses;
a CSP3 step of determining the displacement D of each of the plurality of concave portions based on the strain distribution obtained in CSP1PA displacement amount D from each of the plurality of concave portions obtained from the positions of the plurality of concave portions obtained in the step CSP2MComparing; and
a step CSP4 of making the displacement amount D based on the comparison result obtained in the step CSP3PAnd the displacement DMObtaining the internal Lz of the initial parameter so that the difference becomes smaller0Distribution in the xy plane.
5. The production method according to claim 2 or 4, wherein the step C includes a step CSD in the step CS,
the step CSD is a step of obtaining an initial parameter for obtaining a strain distribution of the entire mask base material in the initial state, the initial parameter being a Young's modulus Yx0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0、Ly0、Lz0At least one of the above-mentioned (b),
the process CSD further includes: a step CSD1 of obtaining a strain distribution of the entire mask base material when at least one dummy opening is formed outside the active region forming portion by a simulation using a finite element method;
a step CSD2 of measuring a position of the at least one virtual opening;
a step CSD3 of determining a displacement D of the at least one virtual opening based on the strain distribution obtained in the step CSD1PdAnd a displacement amount D of the at least one virtual opening determined from the position of the at least one virtual opening obtained in the step CSD2MdComparing; and
a step CSD4 of making the displacement D based on the comparison result obtained in the step CSD3PdAnd the displacement DMdSo that the difference becomes smaller, at least one of the initial parameters is obtained.
6. The manufacturing method according to any one of claims 1 to 5,
the mask substrate is formed with a magnetic metal layer.
7. The manufacturing method according to any one of claims 1 to 5,
the mask base material is formed with a resin layer.
8. The manufacturing method according to claim 7, wherein the film formation mask further includes a magnetic metal layer having at least one through hole exposing the plurality of openings formed in the resin layer.
Technical Field
The present invention relates to a method for manufacturing a film formation mask, and more particularly, to a method for manufacturing a film formation mask suitable for mass production of a high-definition organic EL (Electro Luminescence) display device. The film formation mask is referred to as including masks used in a thin film Deposition technique (e.g., Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), etc.). Hereinafter, a vacuum vapor deposition method, which is one kind of PVD, will be described as an example.
Background
In recent years, organic EL display devices have been put to practical use. In medium-to-small-sized organic EL display devices currently in mass production, the formation of an organic EL layer is mainly performed by using a vacuum deposition method. The organic EL layer includes, for example, a hole transport layer, an electron transport layer, and an organic light emitting layer disposed therebetween. The hole transport layer may also serve as an organic light emitting layer. A layer formed of an organic material and including at least an organic light-emitting layer and an electron-transporting layer is referred to as an organic EL layer.
The organic EL display device includes: at least one organic EL element (OLED) for each pixel and at least one tft (thinfilm transistor) that controls current supplied to each OLED. Hereinafter, the organic EL display device is referred to as an OLED display device. As described above, an OLED display device having a switching element such as a TFT for each OLED is called an active matrix type OLED display device. In addition, a substrate on which the TFT and the OLED are formed is referred to as an element substrate. The driving circuit including the TFT is referred to as a backplane circuit (or simply "backplane"), and the OLED is formed on the backplane.
In an organic EL display device capable of color display, for example, one color display pixel is constituted by an R pixel, a G pixel, and a B pixel. The different color pixels that make up the color display pixels are sometimes also referred to as primary color pixels. The pixel in this specification is sometimes referred to as a "dot", and the color display pixel is referred to as a "pixel". For example, ppi (pixel per inch) indicating the resolution indicates the number of "pixels" contained in 1 inch.
In addition, in the case where one color display pixel is configured by three different color pixels, the three different color pixels may be different in shape and size from each other. For example, a blue pixel having low light emission efficiency may be increased, and a green pixel having high light emission efficiency may be decreased. Alternatively, one color display pixel may be configured by one red pixel, one green pixel, and two blue pixels. The pixel array may be a stripe array, a delta array, or any of various known arrays.
The organic EL layer is formed by a vacuum evaporation method using a film formation mask prepared for each color. In addition to the organic EL layer, an electrode layer (for example, a cathode layer) formed on the organic EL layer may be formed by, for example, a sputtering method using a film formation mask. In addition, an electrode layer (e.g., an anode layer) formed under the organic EL layer may be formed by a photolithography process since the organic EL layer is not exposed to a developing solution.
Conventionally, a Metal Mask (sometimes referred to as FMM) in which a plurality of openings are formed in a Metal layer (Metal plate) in a predetermined pattern has been used as a film formation Mask (for example, patent document 1). In order to cope with the high definition of the OLED display device, a film formation mask (hereinafter, referred to as a "laminated mask") having a laminate in which a resin layer and a magnetic metal layer are laminated, which can form a pattern finer than that of a metal mask, has been proposed (for example, patent documents 2 and 3).
In this specification, a member in which an opening of a film formation mask (a through hole through which a substance to be formed passes) is formed is referred to as a mask base material. In the metal mask, a metal layer (typically, a magnetic metal layer) serves as a mask base material, and in the laminated mask, a resin layer in a laminated body of a resin layer and the magnetic metal layer serves as a mask base material. In addition, a portion of the film formation mask which is in close contact with an active region (also referred to as an "element formation region" or a "display region") of an element substrate to be subjected to film formation (for example, a stepwise element in which a back plate is formed) is referred to as an active region formation portion.
Documents of the prior art
Patent document
Patent document 1: japanese unexamined patent publication No. 2006-188748
Patent document 2: japanese laid-open patent publication No. 2017-82313
Patent document 3: japanese laid-open patent publication No. 2015-10270
Patent document 4: japanese patent No. 4173329 (U.S. Pat. No. 673854)
Disclosure of Invention
Problems to be solved by the invention
In any of the metal mask and the laminated mask, the mask base material is stretched in order to improve the planarity of the active region formation portion. This is because, when the planarity of the active region forming portion is low, that is, when the mask base material of the active region forming portion is loosened, a gap is generated between the active region forming portion and the surface of the element substrate, and a problem occurs in that the film cannot be formed into a predetermined shape.
However, according to the studies of the present inventors, if an opening is formed in a stretched mask base material, the distribution of the direction and magnitude of strain (stress) in the mask base material (simply referred to as "strain distribution (stress distribution)") may be changed by forming the opening, and the position of the opening may be displaced (deviated).
Since the mask base material is stretched (receives a tensile force directed to the outside in the plane), strain (stress) is generated in the mask base material. The strain (stress) is a function of position within the mask substrate. That is, the direction and magnitude of strain (stress) differ depending on the position within the mask base material. The strain (stress) distribution of the mask base material changes every time the opening is formed in the mask base material. Therefore, the accuracy of the position of the opening to be finally obtained also depends on the order of forming the openings. For example, it is particularly problematic in the case of forming a high-definition opening pattern exceeding 200 ppi.
Further, in the film formation mask corresponding to the plurality of active regions, that is, the film formation mask used in association with the mother substrate from which the plurality of OLED display devices are extracted, the same problem as described above occurs because the strain (stress) distribution in the mask base material differs depending on the position of the active region forming portion.
For example, patent document 4 discloses a method for producing a particle beam mask, which includes: the strain generated by forming a plurality of openings of a desired pattern on a mask base material (unprocessed product) is predicted, and a plurality of openings of a desired pattern, which generates a strain opposite to the predicted strain, are formed.
However, patent document 4 does not consider the order of forming the plurality of openings, that is, the change in strain during the process of forming the plurality of openings, and thus cannot solve the above problem.
Further, it is impossible to cope with variations in the thickness of the mask base material (variations among a plurality of mask base materials and variations in the position within each mask base material).
The present invention has been made to solve at least one of the above-described problems, and an object of the present invention is to suppress a decrease in positional accuracy due to a displacement of the position of an opening caused by a change in the strain (stress) distribution of a mask base material (for example, a metal layer of a metal mask or a resin layer of a laminated mask) in a process of manufacturing a film formation mask having the mask base material stretched.
Means for solving the problems
According to an embodiment of the present invention, a solution described in the following items is provided.
[ item 1]
A method for manufacturing a film formation mask, the film formation mask comprising: a frame; a mask base material fixed to the frame in a stretched state; and a plurality of openings provided in the active region forming portion of the mask base material and arranged in a matrix having m rows and n columns, the method for manufacturing a film formation mask comprising:
a step (A) of preparing a mask base material in an initial state, which is fixed to the frame in a stretched state under a predetermined condition so that an xy plane can be defined; a step B of preparing target coordinate data of the positions of the plurality of openings specified in the xy plane;
a step C of predicting a displacement amount of each of the plurality of openings, which is displaced from the target coordinate data due to the formation of the opening, and generating correction data for reducing the displacement amount; and
a step D of forming each of the plurality of openings at a position specified based on the target coordinate data and the correction data,
in the step C, the correction data for each of the plurality of openings is associated with an order of forming the plurality of openings, and
in the step D, the plurality of openings are formed in the stated order.
[ item 2]
The method of manufacturing a film formation mask according to item 1, wherein the step C includes a step CS of obtaining a strain distribution of the entire mask base material when the openings are formed in the order of forming the plurality of openings by a simulation using a finite element method, predicting a displacement amount of each of the plurality of openings based on the strain distribution, and generating the correction data, the step CS including:
a step CS1 of obtaining a displacement D1(k) of a position on the mask base material where a k-th opening is to be formed, based on a strain distribution of the entire mask base material immediately before the k-th opening is formed;
a step CS2 of obtaining a displacement D2(k) of a position on the mask base material where a k-th opening is to be formed, based on a strain distribution of the entire mask base material after all of the plurality of openings are formed; and
in the step CS3, the correction data c (k) of the k-th opening is obtained from D1(k) and D2 (k).
[ item 3]
The manufacturing method according to item 2, wherein an initial parameter (young's modulus Yx) for obtaining a strain distribution of the entire mask base material in the initial state is provided in advance in the step CS0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0、Ly0、Lz0)。
[ item 4]
The manufacturing method according to item 2, wherein the step C includes a step of obtaining an initial parameter (Young's modulus Yx) for obtaining a strain distribution of the entire mask base material in the initial state in the step CS0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0) At least Lz of0A process CSP of distribution in the xy-plane,
the process CSP further comprises: a CSP1 step of obtaining, by simulation using a finite element method, a strain distribution of the entire mask base material when a plurality of recesses having a depth d of 40% or less of the thickness of the mask base material are formed so as to correspond to each of the plurality of openings in the order in which the plurality of openings are formed;
a step CSP2 of measuring the positions of the plurality of formed recesses;
a CSP3 step of determining the displacement D of each of the plurality of concave portions based on the strain distribution obtained in CSP1PA displacement amount D from each of the plurality of concave portions obtained from the positions of the plurality of concave portions obtained in the step CSP2MComparing; and
a step CSP4 of making the displacement amount D based on the comparison result obtained in the step CSP3PAnd the displacement DMObtaining the internal Lz of the initial parameter so that the difference becomes smaller0Distribution in the xy plane.
[ item 5]
The manufacturing method according to item 2 or 4, wherein the step C includes a step of obtaining an initial parameter (Young's modulus Yx) for obtaining a strain distribution of the entire mask base material in the initial state in the step CS0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0) The process CSD of at least one of (a), further comprising: a step CSD1 of obtaining a strain distribution of the entire mask base material when at least one dummy opening is formed outside the active region forming portion by a simulation using a finite element method;
a step CSD2 of measuring a position of the at least one virtual opening; a step CSD3 of determining a displacement D of the at least one virtual opening based on the strain distribution obtained in the step CSD1PdAnd a displacement amount D of the at least one virtual opening determined from the position of the at least one virtual opening obtained in the step CSD2MdComparing; and
a step CSD4 of making the displacement D based on the comparison result obtained in the step CSD3PdAnd the displacement DMdSo that the difference becomes smaller, at least one of the initial parameters is obtained.
[ item 6]
The production method according to any one of items 1 to 5, wherein the mask substrate is formed with a magnetic metal layer.
[ item 7]
The production method according to any one of items 1 to 5, wherein the mask base material is formed with a resin layer.
[ item 8]
The manufacturing method according to item 7, wherein the film formation mask further includes a magnetic metal layer having at least one through hole exposing the plurality of openings formed in the resin layer.
Effects of the invention
According to the embodiments of the present invention, for example, it is possible to suppress a decrease in positional accuracy due to a displacement of the position of the opening caused by a change in the strain (stress) distribution of the mask base material in the process of manufacturing a film formation mask having a stretched mask base material.
Drawings
Fig. 1 is a schematic plan view of a film formation mask 100A manufactured by a manufacturing method according to an embodiment of the present invention.
Fig. 2 is a schematic plan view of a portion 10p of the active region formation portion 10A of the film formation mask 100A.
Fig. 3 is a schematic cross-sectional view of the film formation mask 100B manufactured by the manufacturing method of the embodiment of the invention, showing a cross section along the line 3A-3A in fig. 3.
Fig. 4 is a schematic plan view of the film formation mask 100B.
Fig. 5 is a schematic diagram for explaining the principle of obtaining the displacement amount of the position of the opening due to the change in the strain distribution caused by the formation of the opening in the mask base material in the simulation of the manufacturing method according to the embodiment of the present invention.
Fig. 6 is a schematic diagram showing an example of a result of obtaining a displacement amount of a position of an opening due to a change in strain distribution caused by forming the opening in a mask base material in a simulation in the manufacturing method according to the embodiment of the present invention.
Detailed Description
Hereinafter, a method for manufacturing a film formation mask according to an embodiment of the present invention will be described with reference to the drawings. The embodiments of the present invention are not limited to the embodiments exemplified below.
First, an example of a film formation mask preferably manufactured by the manufacturing method according to the embodiment of the present invention will be described. The manufacturing method according to the embodiment of the present invention is not limited to the film formation mask described below, and can be widely applied to manufacturing of a film formation mask manufactured by forming an opening in a stretched mask base material, for example, as described in patent documents 1 to 3. For reference, the contents of patent documents 1 to 3 are incorporated in their entirety into the present specification.
With reference to fig. 1 and 2, a structure of a film formation mask 100A preferably manufactured by the manufacturing method according to the embodiment of the present invention will be described. Fig. 1 is a schematic plan view of the film formation mask 100A, and fig. 2 is a schematic plan view of a portion 10p of the active region formation portion 10A of the film formation mask 100A. The film formation mask 100A is a metal mask.
As shown in fig. 1, the film formation mask 100A includes a magnetic metal layer 10A and a frame 30A. The magnetic metal layer 10A includes a plurality of openings 11A. The plurality of openings 11A are formed to correspond to the size, shape, and position of the plurality of pixels formed on the element substrate (back plate). The frame 30A is frame-shaped and fixed to the peripheral portion of the magnetic metal layer 20A. The frame 30A is formed of invar, for example.
In the example shown in fig. 2, the plurality of openings 11A are arranged in a matrix. The size, shape, and position of the opening 11A may be different for each emission color of the organic EL layer to be formed. The mask member of the film formation mask 100A is a magnetic metal layer 10A. The magnetic metal layer 10A is preferably made of a magnetic metal material having a small linear thermal expansion coefficient α M (specifically, less than 6ppm/° c). For example, Fe-Ni alloys (invar), Fe-Ni-Co alloys, and the like can be preferably used. The opening 11A can be formed by laser processing, for example.
Next, the structure of the film formation mask 100B preferably manufactured by the manufacturing method according to the embodiment of the present invention will be described with reference to fig. 3 and 4. The film formation mask 100B is a laminated mask. Fig. 3 and 4 are a cross-sectional view and a plan view schematically showing the film formation mask 100B, respectively. Fig. 3 shows a cross-section along line 3A-3A in fig. 4. It is to be noted that fig. 3 and 4 schematically illustrate an example of the film formation mask 100B, and it is needless to say that the size, number, arrangement relationship, ratio of length, and the like of each component are not limited to those illustrated in the drawings. The same applies to other drawings described later.
As shown in fig. 3 and 4, the film formation mask 100B includes a resin layer 10B, a magnetic metal layer 20B, and a frame 30B. When the vapor deposition process is performed using the film formation mask 100B, the film formation mask 100B is disposed such that the magnetic metal layer 20B is positioned on the vapor deposition source side and the resin layer 10B is positioned on the vapor deposition target (element substrate on which the base plate is formed).
The resin layer 10B includes a plurality of openings 11B. The plurality of openings 11B are formed to correspond to the size, shape, and position of the plurality of pixels formed on the element substrate (back plate). In the example shown in fig. 4, the plurality of openings 11B are arranged in a matrix. The size, shape, and position of the opening 11B may be different for each emission color of the organic EL layer to be formed. The mask member of the film formation mask 100B is a resin layer 10B.
As a material of the resin layer 10B, for example, polyimide can be preferably used. Polyimide has a small coefficient of thermal expansion and is excellent in strength, chemical resistance and heat resistance. As a material of the resin layer 10B, another resin material such as polyethylene terephthalate (PET) may be used.
The thickness of the resin layer 10B is not particularly limited. However, when the resin layer 10B is too thick, a part of the vapor deposited film may be formed thinner than desired (referred to as "shadow"). The thickness of the resin layer 10B is preferably 25 μm or less from the viewpoint of suppressing the occurrence of shading. In addition, the thickness of the resin layer 10B is preferably 3 μm or more from the viewpoint of the strength of the resin layer 10B itself and the cleaning resistance.
The magnetic metal layer 20B is formed on the resin layer 10B. As described later, the magnetic metal layer 20B is formed on the resin layer 10B by, for example, a plating method. The magnetic metal layer 20B is in close contact with the resin layer 10B. The magnetic metal layer 20B includes a mask portion 20a and a peripheral portion 20B disposed so as to surround the mask portion 20 a. The mask portion 20a refers to the magnetic metal layer 20B of the active region forming portion.
The mask portion 20a of the magnetic metal layer 20B has a plurality of through holes (slits) 21 that expose the plurality of openings 11B of the resin layer 10B. In the example shown in fig. 4, a plurality of through holes 21 extending in the column direction are arranged in the row direction. Each through-hole 21 has a size larger than each opening 11B of the resin layer 10 when viewed in a normal direction of the film formation mask 100B, and at least one (here, a plurality of) openings 11B are provided in each through-hole 21.
The magnetic metal layer 20B is formed by, for example, electroless plating or electroplating. Preferably a nickel (Ni) plating layer or a nickel alloy plating layer. The resin layer 10B is preferably formed of polyimide so that the coefficient of thermal expansion of the magnetic metal layer 20B is matched to that of the resin layer 10B.
The thickness of the magnetic metal layer 20B is not particularly limited. However, if the magnetic metal layer 20B is too thick, the magnetic metal layer 20B may be bent by its own weight or may be shaded. The thickness of the magnetic metal layer 20B is preferably 100 μm or less, and more preferably 25 μm or less, from the viewpoint of suppressing the occurrence of deflection and shading due to its own weight. Further, if the magnetic metal layer 20B is too thin, the attraction force of the magnetic chuck in the vapor deposition step described later is reduced, which may cause a gap between the film formation mask 100B and the workpiece. In addition, there is a possibility that fracture or deformation occurs, and handling may become difficult. Therefore, the thickness of the magnetic metal layer 20B is preferably 5 μm or more.
The frame 30B is frame-shaped and fixed to the peripheral portion 20B of the magnetic metal layer 20B. That is, the region of the magnetic metal layer 20B that does not overlap the frame 30B is the mask portion 20a, and the region that overlaps the frame 30B is the peripheral portion 20B. The frame 30B is formed of, for example, a metal material. The frame 30B is preferably made of a magnetic metal material having a small linear thermal expansion coefficient α M (specifically, less than 6ppm/° c). For example, Fe-Ni alloys (invar), Fe-Ni-Co alloys, and the like can be preferably used.
In the film formation mask 100B, as shown in fig. 3, the entire magnetic metal layer 20B is joined to the resin layer 10B. The resin layer 10B and the magnetic metal layer 20B receive a tensile force in the in-plane direction from the frame 30B. As described later, in the stretching step, the resin layer 10B and the magnetic metal layer 20B are fixed to the frame 30B in a state of being stretched in the direction into a predetermined layer by a stretching device (or a stretch welding device further having a welding function).
In the method of manufacturing the film formation mask 100B, the openings 11B are formed in the regions exposed from the through holes 21 of the magnetic metal layer 20B on the resin layer 10B.
The opening 11 can be formed by laser processing, for example. Pulsed laser light is used in laser processing. Here, a predetermined region of the resin layer 10 was irradiated with a laser beam L2 having a wavelength of 355nm using the third harmonic of the YAG laser. At this time, the object to be processed (the structure including the frame 30, the magnetic metal layer 20, and the resin layer 10) is inverted in the vertical direction so that the irradiation direction of the laser light L2 is the direction from the top to the bottom. The energy density of the laser L2 is, for example, 0.5J/cm2. The laser processing is performed by focusing the laser light L2 on the surface of the resin layer 10 and emitting it a plurality of times. The number of shots is determined according to the thickness of the resin layer 10. The transmission frequency is set to 60, for exampleHz。
The conditions for laser processing are not limited to the above conditions, and are appropriately selected so that the resin layer 10B can be processed. For example, a laser beam having a large beam diameter may be prepared, and the openings 11 may be formed for each block by irradiating the laser beam through a photomask having openings corresponding to, for example, 50 × 50 openings or 100 × 100 openings 11B.
As described above, when a plurality of openings are formed in sequence by irradiating a mask base material to be set up with, for example, laser light, there is a problem that the positions of the openings are displaced (shifted) due to a change in strain (stress) distribution in the mask base material caused by the formation of the openings. This is a problem common to the above-described methods for manufacturing a metal mask, a laminated mask, or a resin mask (a mask in which a magnetic metal layer is omitted in a laminated mask).
In order to solve the above problems, a method for manufacturing a film formation mask according to an embodiment of the present invention includes the following steps.
Step A: preparing a mask base material in an initial state fixed to the frame in a state of being stretched under a prescribed condition enables a prescribed xy plane. The mask base material is a magnetic metal layer of a metal mask, a laminated mask or a resin layer of a resin mask, in which a plurality of openings are formed in a stretched state, and the initial state is a state in which no opening is formed in the stretched state.
And a step B: target coordinate data of the position in the xy plane of each of the plurality of determined openings is prepared.
And a step C: for each of the plurality of openings, a displacement amount from the target coordinate data, which is caused by the formation of the opening, is predicted, and correction data, in which the displacement amount is subtracted, is generated. At this time, the correction data for each of the plurality of openings is associated with the order in which the plurality of openings are formed. That is, since the entire strain distribution of the mask base material changes according to the order of forming the openings, correction data is generated in consideration of the change.
Step D: each of the plurality of openings is formed at a position determined based on the target coordinate data and the correction data. The sequence in this case is the same as the sequence considered in step C.
The step C may be performed by a known method of simulating a strain (stress) distribution such as a finite element method or a boundary element method. For example, it can be executed using a commercially available finite element method program such as ANSYSShell1811(ANSYS is a registered trademark of ANSYS corporation).
For example, the step C includes a step CS of obtaining a strain distribution of the entire mask base material when the openings are formed in the order of forming the plurality of openings by simulation using a finite element method, predicting a displacement amount of each of the plurality of openings based on the strain distribution, and generating correction data.
The process CS includes, for example: a step CS1 of obtaining a displacement D1(k) of a position on the mask base material where the k-th opening is to be formed, based on the strain distribution of the entire mask base material immediately before the k-th opening is formed, as schematically shown in fig. 5; a step CS2 of obtaining a displacement D2(k) of a position on the mask base material where a k-th opening is to be formed, based on the entire strain distribution of the mask base material after all of the plurality of openings are formed; and a step CS3 of obtaining correction data C (k) of the kth opening from D1(k) and D2 (k). As is clear from fig. 5, the displacement amounts D1(k) and D2(k) are represented by vectors, and the correction data c (k) may be D1(k) -D2(k) so as to cancel out D2(k) -D1 (k).
Next, an example to which the embodiment of the present invention is applied is shown in the method for manufacturing the film formation mask 100A shown in fig. 1 and 2.
The material of the mask substrate was invar, and the parameters used for the simulation were as follows.
Dimension Lx0, Ly of mask base material0、Lz0：410mm、330mm、0.01mm
Young's modulus Yx0、Yy0：1.41X105MPa
Poisson ratio Pxy0: 0.29 (modulus of elasticity in shear Gxy)0Determined from Young's modulus and Poisson's ratio) tension Tx0、Ty0: a forced displacement of 0.114% in the x-direction and 0.037% in the Y-direction.
The size of the opening is 0.64mm (X) x 0.3mm (Y)
Arrangement pitch of opening portions: 0.94mm (X, Y)
Number of openings: 351(X) X266(Y) 93366 pieces
The element numbers are set to 1, 599, 276, and the element types are set to ANSYShell 181.
Fig. 6 is a schematic diagram showing an example of the results of obtaining the displacement amount of the position of the opening due to the change in the strain distribution caused by the formation of the opening in the mask base material in the above simulation. The black dots (dotted lines) represent target coordinate data (TM), and the black squares (solid lines) represent simulation results (SM).
In fig. 6, openings are formed in a row from the lowermost row (row 1) to the uppermost row (row 266), and the strain distribution of the entire mask base material is calculated by the finite element method every time, so that the displacement amount of each opening is obtained. The black squares indicate the displacement amount of each opening after all the openings are formed. For easy understanding, the results of 1000 times the displacement amount of the 5 openings in each row are shown.
As is clear from fig. 6, the positional accuracy of the opening is degraded due to the displacement with respect to the target coordinate data caused by the formation of the opening. By correcting the displacement amount so as to cancel out the displacement amount, the positional accuracy of the opening portion can be improved.
However, the mask base material may not be expressed by a single parameter (the above-described parameter in the initial state) as a whole. In a high-definition metal mask (FMM) or a laminated mask, since a thin mask base material is used, a non-uniform distribution of thickness may occur, and the non-uniform distribution often differs for each mask base material.
When there is a variation in the thickness of the mask base material (a variation between the plurality of mask base materials and a variation in the position within each mask base material), it is preferable that the openings are not penetrated, for example, recesses (100% penetration) having a depth of, for example, 40% or less (for example, 20%) of the thickness of the mask base material are formed at positions corresponding to all the openings, the positions of the xy surfaces of the plurality of recesses formed are measured, and the distribution (variation) of the thickness Lz within the parameters (young's modulus Yx, Yy, shear elastic modulus Gxy, poisson's ratio Pxy, density ρ, tension Tx, Ty, dimension Lx, Ly, Lz) of the mask base material used for simulation is optimized so as to match the measurement result.
Specifically, for example, in the step C, the step CS includes the step CSP, and in the step CSP, at least an initial parameter (young's modulus Yx) for obtaining the strain distribution of the entire mask base material in an initial state is obtained0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0) Lz in (1)0The CSP process comprises a CSP1 process for obtaining the strain distribution of the whole mask base material when a plurality of concave parts with the depth D less than 40% of the thickness of the mask base material are formed corresponding to each of a plurality of opening parts according to the sequence of forming the plurality of opening parts by simulation using a finite element method, a CSP2 process for measuring the positions of the plurality of formed concave parts, and displacement D of each of the plurality of concave parts obtained from the strain distribution obtained in CSP1PAnd a displacement amount D of each of the plurality of concave portions obtained from the positions of the plurality of concave portions obtained in the step CSP2MCSP3 for comparison and determining Lz in initial parameter based on the comparison result obtained in CSP30A step CSP4 of distribution in the xy plane so as to make the displacement amount DPAnd a displacement amount DMThe difference becomes small.
The plurality of openings are preferably formed in the order described in WO/2019/043866 of the present applicant. When a plurality of openings are formed in the order described in WO/2019/043866, the amount of displacement caused by the formation of the openings can be reduced, and as a result, the positional accuracy of the openings can be further improved. The entire disclosure of WO/2019/043866 is incorporated herein by reference for all purposes.
As described in U.S. Pat. No. 57633121, a stress relief opening may be provided outside the active region. The parameters of the mask base material can also be obtained by using the opening for stress relief.
For example, in the step C, the step CS includes a step CSD, and the step CSD obtains an initial strain distribution of the entire mask base material in an initial stateParameter (Young's modulus Yx)0、Yy0Modulus of elasticity in shear Gxy0Poisson ratio Pxy0Density rho0Tension Tx0、Ty0Dimension Lx0, Ly0、Lz0) The step CSD may include a step CSD1 of obtaining a strain distribution of the whole mask base material when at least one dummy opening is formed outside the active region forming portion by a simulation using a finite element method, a step CSD2 of measuring a position of the at least one dummy opening formed, and a displacement D of the at least one dummy opening obtained from the strain distribution obtained in the step CSD1PdAnd a displacement D of at least 1 virtual opening obtained from the position of at least one virtual opening obtained in the step CSD2MdThe step CSD3 of performing comparison and the comparison result obtained from the step CSD3 are calculated as the displacement DPdAnd a displacement amount DMdStep (3) is a step CSD4 of obtaining at least one of the initial parameters so that the difference of (A) is small.
In the above simulation example, the openings are formed in each row, and the entire strain distribution of the mask base material is calculated by the finite element method each time to obtain the displacement amount of each opening. The number of openings to be formed at a time and the order of forming the openings are preferably the same as those in the case of actually forming the openings in the mask base material, but may be simplified or simplified in consideration of the load (calculation time) of simulation. The number of element divisions can be set as appropriate depending on the size of the mask base material and the required accuracy. The shape of the opening is not limited to the illustrated rectangle, and may be appropriately changed to a square, a circle, an ellipse, or the like as needed.
The method of manufacturing the film formation mask according to the embodiment of the present invention can be performed using, for example, a known laser processing machine. For example, a laser processing machine includes: a stage that holds the mask base material at a predetermined position on a predetermined xy plane and can be transferred in the xy plane; a laser irradiation device which irradiates a designated position of the mask base material on the stage with laser light; and a computer that controls the laser irradiation device and the stage.
The laser irradiation device may include a laser light source for emitting laser light, an optical system for directing the laser light in a predetermined direction and/or shaping the beam profile, and the like. The computer irradiates a laser beam with a predetermined energy density to a predetermined position in a predetermined order (for example, by adjusting the pulse width, pulse interval, and number of times of the pulse laser beam), and transmits a command to the laser irradiation device and the stage. The computer further includes a storage device in which a program (for example, ANSYSY Shell181) for obtaining a strain distribution (stress distribution) by the finite element method described above is stored, and performs the simulation described above by using input data (for example, target coordinate data of the opening, the size and shape of the opening, the order of forming the opening, parameters of the mask base material, and the like) with a processor, and transmits a command for determining the position of forming the opening based on the target coordinate data and the correction data to the laser irradiation device and the stage.
Industrial applicability of the invention
Embodiments of the present invention are suitable for manufacturing a film formation mask used in manufacturing, for example, an organic EL device.
Description of the reference numerals
10 resin layer
11A, 11B openings
20B magnetic metal layer
20a mask part
20a1 solid part
20a2 non-solid portion
20b peripheral portion
100A, 100B film formation mask