Method for controlling non-stretching deformation amount of mask and metal mask

Abstract

The present application relates to the technical field of display, and provides a method for controlling non-stretching deformation amount of a mask and a metal mask, comprising: stretching a sample mask with a target film thickness according to a specified deformation amount, measuring a plurality of specified point positions of a pixel area after stretching to obtain non-stretching inward deformation amounts of the plurality of specified point positions of the sample mask; marking an area of the sample mask with a non-stretching inward deformation amount less than a first inward shrinkage threshold value or greater than a second inward shrinkage threshold value as a film thickness adjustment area; obtaining a corresponding relationship between a film thickness change amount and a non-stretching inward deformation amount change amount; calculating a film thickness change amount of the film thickness adjustment area according to the corresponding relationship; and etching a metal film raw material according to the calculated film thickness values of different areas in a pretreatment stage. The present application adjusts the film thickness in the pretreatment stage, so that the non-stretching inward deformation amount of the mask is within the specification, and additional mask cost loss and production time loss are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a method for controlling non-stretching direction deformation amount of mask and metal mask. BACKGROUND

[0002] In the field of display, FMM (Fine Metal Mask) is a key material for OLED (Organic Light Emitting Diode) panel manufacturing. Metal mask is often used for evaporation deposition, before which the metal mask is stretched piece by piece and welded on the metal frame to form an integral net surface, which is called net stretching, and then the metal mask with net stretching is applied to evaporation.

[0003] There are often small through holes, i.e. pixel holes, in the metal mask, and the evaporation material is deposited on the glass substrate through the pixel holes on the net surface after being heated, and the evaporation effect is largely dependent on the control of the pixel hole position accuracy (PPA) in the metal mask during net stretching. After the metal mask is stretched, the non-stretching direction will be deformed to different degrees, and the deformation amount that is too large or too small will lead to the deterioration of the net stretching PPA, thereby further affecting the evaporation effect.

[0004] When the metal mask is stretched, it will be nonlinearly deformed in the non-stretching direction, as shown in FIG. 1, and the current technical solution is to estimate the amount of internal shrinkage in advance, so as to perform external expansion pre-compensation in the non-stretching direction when defining the glass mask pattern of the metal mask, so as to offset the nonlinear internal shrinkage after stretching, so as to achieve the ideal level of PPA after stretching. However, this pre-compensation in the definition of the mask pattern is a one-time fixed type of mask manufacturing, and the metal mask manufactured by the mask will still have a non-stretching direction internal shrinkage amount exceeding the specification, so that the mask must be re-manufactured, thereby causing great loss of mask cost and manufacturing time, and poor flexibility. Figure 1 Therefore, there is a need for a method for flexibly adjusting the non-stretching direction internal shrinkage amount of the metal mask after being stretched to a specified length, reducing production cost and improving product yield.

[0005] SUMMARY The present application relates to the technical field of display, in particular to a method for controlling non-stretching direction deformation amount of mask and metal mask.

[0006] The present application relates to the technical field of display, in particular to a method for controlling non-stretching direction deformation amount of mask and metal mask.

[0007] In a first aspect, an embodiment of the present application provides a method for controlling non-stretching shrinkage of a mask, comprising: stretching a sample mask of a target film thickness by a specified deformation amount, after stretching, setting a plurality of specified point measurements on a pixel area, obtaining a non-stretching shrinkage of a plurality of specified points of the sample mask; marking an area of the sample mask with a non-stretching shrinkage smaller than a first shrinkage threshold or larger than a second shrinkage threshold as a film thickness adjustment area; obtaining a corresponding relationship between a film thickness change amount and a non-stretching shrinkage change amount; calculating a film thickness change amount of the film thickness adjustment area according to the corresponding relationship; and etching a metal film raw material according to the calculated film thickness values of different areas in a pretreatment stage.

[0008] Further, the pixel area includes a plurality of pixel opening points, the plurality of specified points include a plurality of pixel opening points on the edge of the pixel area symmetric to the central axis along the stretching direction, and the pixel area is spaced apart from adjacent specified points on the same line along the stretching direction by a first distance.

[0009] Further, the corresponding relationship between the film thickness change amount and the non-stretching shrinkage change amount includes: stretching masks of different film thicknesses by the specified deformation amount; obtaining respective non-stretching shrinkage of the masks of different film thicknesses; taking the film thickness change amount as the independent variable and the non-stretching shrinkage change amount as the dependent variable, and fitting to obtain the corresponding relationship between the film thickness change amount and the non-stretching shrinkage change amount.

[0010] Further, the obtaining of the respective non-stretching shrinkage of the masks of different film thicknesses includes: measuring the non-stretching shrinkage of a plurality of measurement points on the masks of different film thicknesses; and taking the mean value of the non-stretching shrinkage of the plurality of measurement points of a mask of a certain film thickness as the non-stretching shrinkage of the mask of the certain film thickness.

[0011] Further, the calculating of the film thickness change amount of the film thickness adjustment area according to the corresponding relationship includes: obtaining a first compensation deformation amount by subtracting the non-stretching shrinkage from the first shrinkage threshold, and bringing the first compensation deformation amount into the corresponding relationship to obtain the film thickness change amount of the area where the specified point is located; or / and, obtaining a second compensation deformation amount by subtracting the non-stretching shrinkage from the second shrinkage threshold, and bringing the second compensation deformation amount into the corresponding relationship to obtain the film thickness change amount of the area where the specified point is located.

[0012] Further, the film thickness change amount is less than or equal to 4.5% of the target film thickness.

[0013] Further, the first shrinkage threshold is 1.5 microns, and the second shrinkage threshold is 6 microns.

[0014] Further, the etching of the metal thin film raw material according to the calculated film thickness values of different regions in the pre-processing stage includes: thinning the metal thin film raw material to make a mask plate in the pre-processing stage; the film thickness of the film thickness adjustment region of the mask plate is equal to the sum of the target film thickness and the film thickness variation, and the film thickness of the remaining region is equal to the target film thickness.

[0015] Further, controlling the travel speed of the metal thin film raw material changes the film thickness of different regions of the mask plate; or / and, controlling the temperature distribution of the metal thin film raw material changes the film thickness of different regions of the mask plate.

[0016] In a second aspect, the embodiments of the present application also provide a metal mask plate prepared by the method for controlling the non-stretching direction deformation amount of the mask plate in any one of the preceding.

[0017] The embodiments of the present application have at least the following technical effects:

[0018] The method for controlling the non-stretching direction deformation amount of the mask plate provided by the embodiments of the present application is non-linear in the non-stretching direction shrinkage deformation amount of the sample mask plate, so it is necessary to obtain the non-stretching direction shrinkage deformation amount of multiple pairs of specified points of the sample mask plate. First, the sample mask plate with the target film thickness is stretched according to the specified deformation amount, and multiple specified point positions are measured after stretching in the pixel area. Multiple pairs of specified points are measured in the length direction of the whole sample mask plate, and the length direction refers to the stretching direction of the sample mask plate when the screen is stretched. Each pair of specified points is symmetrical about the central axis of the sample mask plate parallel to the length direction. The non-stretching direction shrinkage deformation amount of the sample mask plate includes the shrinkage amount of the corresponding region of each pair of specified points. The non-stretching direction shrinkage deformation amount of the corresponding region of each pair of specified points is equal to the PPAY (Y direction pixel position accuracy, i.e. non-stretching direction pixel position accuracy) of the upper point minus the PPAY of the lower point. The sample mask plate has different non-stretching direction shrinkage deformation amounts in different regions. If the non-stretching direction shrinkage deformation amount of a certain region is greater than or equal to the first shrinkage threshold and less than or equal to the second shrinkage threshold, that is, the non-stretching direction shrinkage deformation amount of the region is within the specification, and if the non-stretching direction shrinkage deformation amount of a certain region is less than the first shrinkage threshold or greater than the second shrinkage threshold, it means that the non-stretching direction shrinkage deformation amount of the region exceeds the specification, so the region of the sample mask plate with the non-stretching direction shrinkage deformation amount less than the first shrinkage threshold or greater than the second shrinkage threshold needs to be marked as a film thickness adjustment region.

[0019] The film thickness adjustment is based on the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation. To adjust the non-stretching inward shrinkage variation of the film thickness adjustment region to within the specification, a non-stretching inward shrinkage variation change is generated. The change is brought into the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation, so that the film thickness of the region corresponding to a certain pair of specified points needs to be changed. According to this method, the film thickness of each region in the film thickness adjustment region should be adjusted. After the calculation is completed, in the subsequent process of preparing the mask plate, the metal film raw material is etched according to the calculated film thickness values of different regions in the pretreatment stage, so that the non-stretching inward shrinkage variation of the film thickness adjustment region of the newly prepared mask plate is within the specification.

[0020] Generally, the pretreatment stage is only a uniform thinning process for the metal film raw material. However, the film thickness of the film thickness adjustment region of the mask plate is adjusted in the pretreatment stage. Not only can the non-stretching inward shrinkage variation of the mask plate be controlled within the specification, but also the pretreatment itself is the original process node of mask plate preparation. Therefore, this change does not add new process nodes. The film thickness of each region is adjusted in the original pretreatment stage, which does not increase the production cost and avoids additional cost and reduction of production efficiency caused by modifying the mask.

[0021] Therefore, the non-stretching inward shrinkage variation is compared with the first inward shrinkage threshold and the second inward shrinkage threshold to determine which part of the film thickness of the mask plate needs to be adjusted. Then, the film thickness variation is calculated according to the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation change, and the film thickness is adjusted in the pretreatment stage. Not only does the newly prepared mask plate have a non-stretching inward shrinkage variation within the specification, but also the product yield is improved, the mask cost and manufacturing time are avoided, and the production cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0023] Figure 1 A schematic diagram of the deformation of the metal mask plate during stretching;

[0024] Figure 2 A flowchart of a method for controlling the non-stretching deformation of a mask plate according to an embodiment of the present application;

[0025] Figure 3 A schematic diagram of a flow chart for obtaining a corresponding relationship between a change in film thickness and a change in a non-stretched inward deformation variable provided by an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of a process for obtaining respective non-stretched inward shrinkage variables of masks with different film thicknesses provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions of the present invention are described clearly and completely below with reference to the embodiments. It is obvious that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0028] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless specifically defined as such, will not be interpreted in an idealized or overly formal sense.

[0029] It will be understood by those skilled in the art that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. The term "and / or" used herein includes all or any one of the associated listed items and all combinations thereof.

[0030] For the first aspect, see Figure 1 and Figure 2 An embodiment of the present invention provides a method for controlling the non-tensile deformation of a mask, comprising:

[0031] S100: stretching a sample mask of a target film thickness according to a specified deformation amount, setting a plurality of specified points in a pixel area for measurement after stretching, and obtaining non-stretched inward shrinkage deformation amounts of the plurality of pairs of specified points of the sample mask.

[0032] S200: marking an area of ​​the sample mask where the amount of non-stretched inward deformation is less than a first inward deformation threshold or greater than a second inward deformation threshold as a film thickness adjustment area.

[0033] S300: Obtaining a corresponding relationship between a change in film thickness and a change in a non-stretching inward deformation variable.

[0034] S400: Calculating the film thickness variation in the film thickness adjustment area according to the corresponding relationship.

[0035] S500: In the pre-processing stage, the metal thin film raw material is etched according to the calculated film thickness values ​​of different areas.

[0036] In this embodiment, the non-stretched inward deformation variable of the sample mask is non-linear, so it is necessary to obtain the non-stretched inward deformation variables of multiple pairs of designated points on the sample mask. First, the sample mask of the target film thickness is stretched according to the designated deformation variable. After stretching, multiple designated points are set for measurement in the pixel area. Multiple pairs of designated points are measured along the length of the entire sample mask ( Figure 1 Not fully shown in the figure), for example, points A1 and A2 represent a pair of designated points, and points B1 and B2 represent a pair of designated points. The length direction refers to the stretching direction of the sample mask when the mesh is stretched. Each pair of designated points is symmetrical about the central axis of the sample mask parallel to the length direction. For example, points A1 and A2 are symmetrical about the central axis of the sample mask parallel to the length direction, and points B1 and B2 are symmetrical about the central axis of the sample mask parallel to the length direction. The non-stretching inward deformation variable of the sample mask includes the inward shrinkage of the area corresponding to each pair of designated points. The non-stretching inward deformation variable of the area corresponding to each pair of designated points is equal to the PPAY (Y-axis pixel position accuracy, i.e., non-stretching pixel position accuracy) of the upper point (such as point A1) minus the PPAY of the lower point (such as point A2). The sample mask has different non-stretching inward deformation variables in different areas. If the non-stretching inward deformation variable of a certain area is greater than or equal to the first shrinkage threshold and less than or equal to the second shrinkage threshold, it means that the non-stretching inward deformation variable of the area is within the specification. If the non-stretching inward deformation variable of a certain area is less than the first shrinkage threshold, or greater than the second shrinkage threshold, it means that the non-stretching inward deformation variable of the area exceeds the specification. Therefore, it is necessary to mark the area on the sample mask where the non-stretching inward deformation variable is less than the first shrinkage threshold, or greater than the second shrinkage threshold as a film thickness adjustment area.

[0037] The film thickness adjustment is based on the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation. To adjust the non-stretching inward shrinkage variation of the film thickness adjustment region to within the specification also means that the non-stretching inward shrinkage variation is changed. The variation is brought into the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation, so that the film thickness of the region corresponding to a certain pair of specified points needs to be changed. According to this method, the film thickness of each region in the film thickness adjustment region should be adjusted. After the calculation is completed, in the subsequent process of preparing the mask plate, the metal film raw material is etched according to the calculated film thickness values of different regions in the pretreatment stage, so that the non-stretching inward shrinkage variation of the film thickness adjustment region of the newly prepared mask plate is within the specification.

[0038] The general pretreatment stage is only a uniform thinning process for the metal film raw material. For example, the target film thickness of the sample mask plate is 30 microns, and the raw material with a thickness of 100 microns is thinned to 30 microns. Then the thickness of the mask plate produced is 30 microns. However, the film thickness of the film thickness adjustment region of the mask plate is adjusted in the pretreatment stage in the present application. Not only can the non-stretching inward shrinkage variation of the mask plate be controlled within the specification, but also the pretreatment itself is the original process node of mask plate preparation. Therefore, this change does not add new process nodes. Only the film thickness of each region is adjusted in the original pretreatment stage, which does not increase the production cost and avoids additional cost and reduction of production efficiency caused by modification of the mask.

[0039] Therefore, the present application determines which part of the film thickness of the mask plate needs to be adjusted by comparing the non-stretching inward shrinkage variation with the first inward shrinkage threshold and the second inward shrinkage threshold. Then the film thickness variation is calculated according to the corresponding relationship between the film thickness variation and the non-stretching inward shrinkage variation, and the film thickness is adjusted in the pretreatment stage. Not only does the newly prepared mask plate have a non-stretching inward shrinkage variation within the specification, but also the product yield is improved, the mask cost is avoided, and the production cost is reduced.

[0040] It should be noted that step S300 can be performed before step S100 or S200, or step S300 can be performed simultaneously with step S100 or / and S200, which does not affect the result of calculating the film thickness variation of the film thickness adjustment region according to the corresponding relationship in step S400.

[0041] It should be noted that the non-stretching inward shrinkage variation of the multiple pairs of specified points of the sample mask plate can be measured by multiple sample mask plates. The non-stretching inward shrinkage variation of each pair of specified points should be the average of the non-stretching inward shrinkage variation of the multiple sample mask plates at the specified point.

[0042] It should be noted that the target film thickness of the sample mask in this application is 30 microns, and the metal film raw material thickness is 100 microns. It does not mean that the target film thickness of the sample mask can only be 30 microns, and the metal film raw material thickness can only be 100 microns. The target film thickness of the sample mask can be 10 microns, 20 microns, 40 microns, etc. according to the actual production required film thickness value, and the metal film raw material thickness can also be 150 microns, 200 microns, etc. Actual raw material thickness, only to illustrate that the target film thickness of the sample mask is less than the film thickness of the metal film raw material.

[0043] Optionally, the pixel area includes a plurality of pixel opening points, and the plurality of pairs of specified points include partial pixel opening points of the edges of the pixel area which are symmetric about the central axis parallel to the stretching direction, and adjacent specified points on the same line in the stretching direction in the pixel area are spaced apart by a first distance.

[0044] In this embodiment, the pixel area is densely covered with pixel opening points, and the distance between adjacent pixel opening points is very small. Therefore, the plurality of pairs of specified points measured by the present application are partial pixel opening points of the upper and lower edges in the pixel area, and each pair of specified points is spaced apart by a first distance in the length direction. For example, the first distance can be 1mm, 3mm, or 5mm, or 10mm, etc. That is, the pixel opening points at intervals of 1mm, 3mm, 5mm, or 10mm in the length direction are taken as specified points. For example, if a specified point is set every 1mm, there will be more than 800 pairs of specified point coordinates along the length direction. The X coordinates of the two points in a pair of specified points are the same, but the Y coordinates are different, so more than 800 non-stretching inward deformation variable values will be generated. Alternatively, the first distance is a multiple of the distance between adjacent pixel opening points, that is, the pixel opening points every 1, 3, 10, 20, or 30, etc. pixel opening points in the length direction are taken as specified points.

[0045] It should be noted that the numbers given here are only for easy understanding and are not a limitation on the value of the first distance. In addition, it should be noted that if the mask includes a plurality of pixel areas, and there is a certain distance between the two adjacent pixel areas, then the distance between the two adjacent pairs of specified points in each pixel area is the first distance. If the two pairs of adjacent specified points belong to two adjacent pixel areas, then the distance between the two pairs of adjacent specified points in the length direction is not necessarily the first distance. Each pair of specified points represents an area that is the position of the specified point plus an area of one-half of the first distance on both sides.

[0046] Optionally, referring to Figure 3 , step S300: obtaining a corresponding relationship between the film thickness change and the non-stretching inward deformation variable change includes:

[0047] S301: Stretching the mask with different film thicknesses by a specified deformation amount.

[0048] S302: Obtaining the respective non-stretching inward shrinkage amounts of the masks with different film thicknesses.

[0049] S303: Fitting the corresponding relationship between the change amount of the film thickness and the change amount of the non-stretching inward shrinkage amount, taking the change amount of the film thickness as the independent variable and the change amount of the non-stretching inward shrinkage amount as the dependent variable.

[0050] In this embodiment, in order to obtain the corresponding relationship between the change amount of the film thickness and the change amount of the non-stretching inward shrinkage amount, the masks with different film thicknesses need to be stretched by a specified deformation amount. The masks with different film thicknesses differ from the sample mask in that only the film thickness is different. For example, if the film thickness of the sample mask is 30 microns, masks with different thicknesses of 25-35 microns can be selected to obtain the non-stretching inward shrinkage amount of the masks with different film thicknesses. At this time, taking the change amount of the film thickness as the independent variable, for example, the change amount of the film thickness can be 0.2 microns, 0.5 microns, 1 micron, 2 microns, 5 microns, etc., and taking the change amount of the non-stretching inward shrinkage amount as the dependent variable, the corresponding relationship is fitted. It can be envisaged that the fitting here can be linear or non-linear, which needs to be selected appropriately according to the measured data, and can also be verified inversely according to the subsequent calculation of the film thickness change amount of the film thickness adjustment area. It should be noted that the numbers given here are only for easy understanding and are not a limitation on the values of the film thickness change.

[0051] Optionally, please refer to Figure 4 S302: Obtaining the respective non-stretching inward shrinkage amounts of the masks with different film thicknesses includes:

[0052] S3021: Measuring the non-stretching inward shrinkage amounts of multiple pairs of measurement points on the masks with different film thicknesses.

[0053] S3022: Taking the average of the non-stretching inward shrinkage amounts of multiple measurement points of a mask with a certain film thickness as the non-stretching inward shrinkage amount of the mask with the certain film thickness.

[0054] In the embodiment, the non-stretching inward shrinkage variables of the mask in each region along the length direction are different, and therefore the non-stretching inward shrinkage variable of each mask needs to be selected by selecting multiple pairs of measuring points at the upper and lower edges along the length direction, and then taking the average of the non-stretching inward shrinkage variables of the multiple pairs of measuring points as the non-stretching inward shrinkage variable of the mask of a certain film thickness. Taking the non-stretching inward shrinkage variable of the mask of the film thickness of 29 microns as an example, 15 pairs of measuring points need to be selected at the upper and lower edges along the length direction on the mask, and then there are 15 values of the non-stretching inward shrinkage variable, and the non-stretching inward shrinkage variable of the mask of the film thickness of 29 microns is the average of the 15 non-stretching inward shrinkage variables. The non-stretching inward shrinkage variables of the masks of other film thicknesses are obtained in the same way. In order to ensure the reliability of the data, at least 10 pairs of measuring points should be selected, and each pair of measuring points is preferably located in the pixel area and has a uniform interval. It can also be considered that more than one mask of the same thickness is selected for measurement, and the final non-stretching inward shrinkage variable of the mask of a certain film thickness should be the average of the non-stretching inward shrinkage variables of the multiple masks. It should be noted that the measuring points for obtaining the respective non-stretching inward shrinkage variables of the masks of different film thicknesses can be different from the specified points of the sample mask in the previous steps.

[0055] Optionally, the film thickness change amount of the film thickness adjustment region is calculated according to the corresponding relationship formula, including: a first compensation deformation variable is obtained by subtracting the non-stretching inward shrinkage variable from the first inward shrinkage threshold value, and the first compensation deformation variable is brought into the corresponding relationship formula to obtain the film thickness change amount of the region where the specified point is located; or / and, a second compensation deformation variable is obtained by subtracting the non-stretching inward shrinkage variable from the second inward shrinkage threshold value, and the second compensation deformation variable is brought into the corresponding relationship formula to obtain the film thickness change amount of the region where the specified point is located.

[0056] In the embodiment, the calculation method of the film thickness change amount of the film thickness adjustment region, whether the non-stretching inward shrinkage variable of a certain specified point is less than the first inward shrinkage threshold value or greater than the second inward shrinkage threshold value, can be that a first compensation deformation variable is obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the first inward shrinkage threshold value, and the first compensation deformation variable is brought into the corresponding relationship formula to obtain the film thickness change amount of the region where the specified point is located, so that the non-stretching inward shrinkage variable of the specified point satisfies the minimum specification deformation through the change of the film thickness; or / and, a second compensation deformation variable is obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the second inward shrinkage threshold value, and the second compensation deformation variable is brought into the corresponding relationship formula to obtain the film thickness change amount of the region where the specified point is located, so that the non-stretching inward shrinkage variable of the specified point satisfies the maximum specification deformation through the change of the film thickness. It should be noted that the first compensation deformation variable or the second compensation deformation variable is brought into the corresponding relationship formula as the change amount of the non-stretching inward shrinkage variable, and therefore the film thickness change amount can be obtained.

[0057] Therefore, the non-stretching inward shrinkage variables of the multiple pairs of specified points in the film thickness adjustment region, whether all are less than the first inward shrinkage threshold, or all are greater than the second inward shrinkage threshold, or part is less than the first inward shrinkage threshold and part is greater than the second inward shrinkage threshold, can all adopt the first compensation deformation variable obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the first inward shrinkage threshold, and the film thickness change amount of the region where the specified point is located is obtained by bringing the first compensation deformation variable into the corresponding relationship formula, so that the non-stretching inward shrinkage variable of the film thickness adjustment region meets the minimum specification deformation through the change of the film thickness; or all can adopt the second compensation deformation variable obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the second inward shrinkage threshold, and the film thickness change amount of the region where the specified point is located is obtained by bringing the second compensation deformation variable into the corresponding relationship formula, so that the non-stretching inward shrinkage variable of the film thickness adjustment region meets the maximum specification deformation through the change of the film thickness; or a part of the specified points can adopt the first compensation deformation variable obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the first inward shrinkage threshold, and the film thickness change amount of the region where the specified point is located is obtained by bringing the first compensation deformation variable into the corresponding relationship formula, and the rest of the specified points can adopt the second compensation deformation variable obtained by subtracting the non-stretching inward shrinkage variable of the specified point from the second inward shrinkage threshold, and the film thickness change amount of the region where the specified point is located is obtained by bringing the second compensation deformation variable into the corresponding relationship formula, and the non-stretching inward shrinkage variable of the region corresponding to the specified point of the mask manufactured should be within the specification.

[0058] Optionally, the film thickness variation is less than or equal to 4.5% of the target film thickness. In this embodiment, in order to reduce the impact on the subsequent evaporation effect, when calculating the film thickness variation of the film thickness adjustment area, it should be noted that the film thickness variation of the area represented by any specified point cannot exceed 4.5% of the original mask film thickness (i.e. the target film thickness), that is, the maximum film thickness variation is 4.5% of the target film thickness, regardless of whether the film thickness increases or decreases. Taking a target film thickness of 30 microns as an example, that is, the sample mask film thickness is 30 microns, when the film thickness of the film thickness adjustment area is adjusted, the film thickness variation of the area represented by the specified point is at most 1.35 microns, which means that the film thickness variation range of the mask prepared subsequently in the film thickness adjustment area is 28.65-31.35 microns, which is to prevent the thickness of the entire mask surface from changing abruptly. If the film thickness variation is too large, the hole depth of the mask opening through which the RGB three-color substances pass during the downstream evaporation process will change too much, which will affect the evaporation effect. By analogy, the film thickness variation of the film thickness adjustment area of the remaining target film thickness is also calculated in the same way. When selecting the calculation method of the film thickness variation of the film thickness adjustment area, this restriction can also be considered, so that the film thickness variation is less than or equal to 4.5% of the target film thickness.

[0059] Optionally, the first shrinkage threshold is 1.5 microns and the second shrinkage threshold is 6 microns. In this embodiment, the first shrinkage threshold and the second shrinkage threshold can be understood as the allowable shrinkage amount of the pixel opening point on the two upper and lower edges of the mask in the non-stretching direction when the mask is stretched, which needs to be within these two numerical ranges, because too large or too small shrinkage will cause the subsequent screen PPA to deteriorate. If the non-stretching shrinkage of a specified point is greater than or equal to 1.5 microns and less than or equal to 6 microns, the non-stretching shrinkage of the area represented by the specified point is within the specification, and the film thickness does not need to be changed; if the non-stretching shrinkage of a specified point is less than 1.5 microns (i.e. the shrinkage is too small) or greater than 6 microns (i.e. the shrinkage is too large), the non-stretching shrinkage of the area represented by the specified point is out of specification, and the film thickness needs to be adjusted.

[0060] Optionally, in the pretreatment stage, the metal thin film raw material is etched according to the calculated film thickness values of different regions, including: thinning the metal thin film raw material to produce a mask film; the film thickness of the film thickness adjustment area of the mask film is equal to the sum of the target film thickness and the film thickness variation, and the film thickness of the remaining area is equal to the target film thickness.

[0061] In the preparation of the mask in the embodiment, the metal film raw material with a relatively thick film thickness is first processed into a target film thickness required by the mask in a pretreatment stage. The general pretreatment stage is a process of uniformly thinning the metal film raw material by etching, but in the present application, the raw material is etched into different thicknesses of plates in the pretreatment stage. At this time, the newly manufactured mask has the same pattern as the sample mask, and the film thickness of the film thickness adjustment area of the newly manufactured mask is equal to the sum of the target film thickness and the film thickness variation. The film thickness variation can be positive or negative, which is determined according to the corresponding relationship between the film thickness variation and the non-stretching inward deformation variation. If the film thickness variation of a region represented by a specified point in the film thickness adjustment area is positive, the film thickness of the region represented by the specified point is greater than the target film thickness. If the film thickness variation of a region represented by a specified point in the film thickness adjustment area is negative, the film thickness of the region represented by the specified point is less than the target film thickness. The other areas of the newly manufactured mask still maintain the target film thickness.

[0062] Taking the target film thickness of 30 microns as an example, the metal film raw material with a film thickness of 100 microns needs to be etched by 70 microns in the areas other than the film thickness adjustment area, leaving 30 microns. However, some areas in the film thickness adjustment area may etch away 71 microns, leaving 29 microns, and some areas may etch away 69 microns, leaving 31 microns. It should be noted that the numbers in the example are only for easy understanding, and the film thickness variation of the film thickness adjustment area should be determined according to the corresponding relationship between the film thickness variation and the non-stretching inward deformation variation.

[0063] Alternatively, the film thickness of different areas of the mask can be changed by controlling the travel speed of the metal film raw material, or / and the film thickness of different areas of the mask can be changed by controlling the temperature distribution of the metal film raw material. In the embodiment, to change the metal film raw material into different film thicknesses, the method used can be to control the travel speed of the metal film raw material, so that the etching time of the chemical liquid is different, and thus the etching depth is different. Alternatively, the metal film raw material can be heated to different temperature distributions according to different film thickness requirements, so that the etching efficiency of the chemical liquid is different, and thus the etching depth is different. Alternatively, the two methods can be combined to make the adjustment of the film thickness more efficient.

[0064] In a second aspect, the embodiment of the present application provides a metal mask prepared by the method of controlling the non-stretching inward deformation variable of the mask in the first aspect. The metal mask in the embodiment has different film thicknesses in different areas, ensuring that the non-stretching inward deformation variable of the entire metal mask is within the specification when the mask is stretched.

[0065] Those skilled in the art can understand that the steps, measures, and schemes in various operations, methods, and processes discussed in the present application can be alternated, changed, combined, or deleted. Further, other steps, measures, and schemes in various operations, methods, and processes discussed in the present application can also be alternated, changed, rearranged, decomposed, combined, or deleted. Further, steps, measures, and schemes in various operations, methods, and processes in the prior art can also be alternated, changed, rearranged, decomposed, combined, or deleted.

[0066] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0067] The terms "first", "second", are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0068] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0069] In the description of the present application, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0070] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of controlling the non-tensile direction of a mask, characterized in that, The method comprises the following steps: stretches a sample mask plate of a target film thickness by a specified deformation variable, and sets a plurality of specified point positions in a pixel area after stretching, to obtain a plurality of pairs of specified point positions of the non-stretching inward deformation variable of the sample mask plate; marks an area of the sample mask plate with a non-stretching inward deformation variable less than a first inward shrinkage threshold value or greater than a second inward shrinkage threshold value as a film thickness adjustment area; obtains a corresponding relationship between the change amount of the film thickness and the change amount of the non-stretching inward deformation variable; calculates the film thickness change amount of the film thickness adjustment area according to the corresponding relationship; etches a metal thin film raw material according to the calculated film thickness values of different areas in a pretreatment stage; the corresponding relationship between the change amount of the film thickness and the change amount of the non-stretching inward deformation variable comprises: stretching mask plates with different film thicknesses by the specified deformation variable; obtaining the respective non-stretching inward deformation variables of the mask plates with different film thicknesses; fitting to obtain the corresponding relationship between the change amount of the film thickness and the change amount of the non-stretching inward deformation variable, with the change amount of the film thickness as the independent variable and the change amount of the non-stretching inward deformation variable as the dependent variable.

2. The method of controlling the non-stretching direction of a mask according to claim 1, wherein, The pixel area comprises a plurality of pixel opening points, and the plurality of pairs of specified point positions comprise a plurality of pixel opening points on the edge of the pixel area symmetrically along the central axis in the stretching direction, and the pixel area is spaced apart by a first distance between adjacent specified point positions on the same line in the stretching direction.

3. The method of controlling the non-stretching direction of a mask according to claim 1, wherein, The method comprises the following steps: measuring the non-stretching inward deformation variables of a plurality of pairs of measurement points on mask plates with different film thicknesses; taking the average of the non-stretching inward deformation variables of a plurality of pairs of measurement points of a mask plate with a certain film thickness as the non-stretching inward deformation variable of the mask plate with the certain film thickness.

4. The method of controlling the non-stretching direction of a mask according to claim 1, wherein, The method comprises the following steps: adopting the first inward shrinkage threshold value to subtract the non-stretching inward deformation variable to obtain a first compensation deformation variable, and bringing the first compensation deformation variable into the corresponding relationship to obtain the film thickness change amount of the area where the specified point position is located; or / and, adopting the second inward shrinkage threshold value to subtract the non-stretching inward deformation variable to obtain a second compensation deformation variable, and bringing the second compensation deformation variable into the corresponding relationship to obtain the film thickness change amount of the area where the specified point position is located.

5. The method of controlling the non-stretching trans- formative amount of a shadow mask according to claim 4, wherein, The film thickness change amount is less than or equal to 4.5% of the target film thickness.

6. The method of controlling the non-stretching amount of a mask according to claim 1, wherein The first inward shrinkage threshold value is 1.5 microns, and the second inward shrinkage threshold value is 6 microns.

7. The method of controlling the non-stretching amount of a mask according to claim 1, wherein The method comprises the following steps: performing a thinning treatment on the metal thin film raw material to manufacture the mask plate in the pretreatment stage; The film thickness of the film thickness adjustment area of the mask plate is equal to the sum of the target film thickness and the film thickness change amount, and the film thickness of the remaining area is equal to the target film thickness.

8. The method of controlling the non-stretching amount of a mask according to claim 7, wherein Controlling the travel speed of the metal thin film raw material changes the film thickness of different areas of the mask plate; or / and, controlling the temperature distribution of the metal thin film raw material changes the film thickness of different areas of the mask plate.

9. A metal mask, characterized by The method is prepared by the method for controlling the non-stretching inward deformation variable of the mask plate according to any one of claims 1-8.

Images