TW201718904A - Metal mask material and metal mask capable of improving accuracy of the etching process and accurately detecting its own defect - Google Patents

Abstract

The present invention provides a metal mask material and a metal mask capable of improving accuracy of the etching process and accurately detecting its own defect. The present invention relates to a metal mask material which is constituted by a rolled plate of Fe-Ni based alloy, wherein the rolled plate of Fe-Ni based alloy contains 30~45 mass% of Ni and Co, 0~6 mass% of Co, balance of Fe and inevitable impurities. The thickness t of the metal mask material exceeds 0.08 mm. The arithmetic mean roughness Ra measured in accordance with JIS-B0601 in the directions parallel to the rolling and perpendicular to the rolling is 0.01~0.20[mu]m, and the 60 degree glossiness G60 measured in accordance with JIS-Z8741 in the directions parallel to the rolling and perpendicular to the rolling is 200~600.

Description

Metal mask material and metal mask

The present invention relates to a metal mask material and a metal mask used in the manufacture of an organic EL display or the like.

Compared with the current mainstream liquid crystal display among flat panel displays, the organic EL display has the following features: the structure is simple, the product can be made thinner, the display of the fast moving image is smooth, and the viewing angle is wider. The organic EL display has been mass-produced in a small-sized device such as a mobile terminal, and is being used as a main force of a next-generation display, and is being put into practical use in a large-sized display.

As a method of producing an EL (light-emitting) layer of an organic EL display, a vapor deposition method and a printing method are roughly classified. The vapor deposition method is a method in which an EL material heated and evaporated in a vacuum is attached to the surface of a substrate in the form of a thin layer. Further, the printing method is a method of producing an EL layer by printing on the surface of a substrate. In the vapor deposition method, there are a type in which three colors of RGB (red, green, and blue) are emitted, and a type in which the EL layer emits white light.

In the vapor deposition method, there is a color patterning step of forming a EL layer in a specific pattern for a specific position of a substrate, and providing a metal mask between the vapor deposition source and the substrate. The metal mask is composed of a metal plate or foil having an opening corresponding to the pattern of the EL layer. The EL material that has evaporated from the evaporation source and is released into the vacuum reaches the metal mask, and passes through the EL of the opening of the metal mask. The material adheres to the substrate to form an EL layer having a specific pattern.

However, in the color patterning step, there is a case where the organic material having a high temperature adheres to the surface of the metal mask due to the radiant heat from the vapor deposition source, and the temperature of the metal mask rises to about 100 ° C. In order to maintain the accuracy of the forming position on the substrate, the metal mask must use a material having thermal expansion of the same level or less as the substrate. In particular, the pattern of the EL layer of the type of RGB three-color light must be formed one by one for the three colors of RGB, so that it is important to suppress the shift of the forming position due to the expansion of the metal mask.

Regarding the thickness of the metal mask, a foil of 0.02 to 0.08 mm is mainly used for the type of light emitting RGB, and a plate of 0.08 to 0.25 mm is mainly used for the type of white light emitted from the EL layer.

However, when the pattern of the metal mask is made fine, the portion of the mask that is sandwiched by the opening of the mask is thinned, the strength is lowered, and the shape of the opening is deformed by the deflection.

Therefore, as a method of simultaneously realizing the strength of the metal mask and the shape accuracy of the opening portion, there is disclosed a technique in which a reinforcing metal wire is partially provided to prevent bending of a metal mask having a small thickness (Patent Document 1); A technique in which one opening of a metal forming mask is formed by bonding the opening forming layer to another supporting layer (Patent Documents 2 and 3). Further, a technique for controlling surface roughness and improving etching processing accuracy has been disclosed (Patent Document 4).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-50478

[Patent Document 2] Japanese Patent No. 4126648

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2004-039628

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2010-214447

However, in the case of the technique disclosed in Patent Document 1, since the organic material is not attached to the portion of the back side of the reinforcing metal wire, a phenomenon similar to the shadow effect is generated, and the shape accuracy of the organic material formed on the substrate is changed. difference. Further, in the case of the techniques disclosed in Patent Documents 2 and 3, in order to manufacture one metal mask, two metal foils are required, and it is necessary to bond the metal foils with high precision, so the metal mask forming step It becomes complicated and leads to an increase in manufacturing costs.

On the other hand, in the step of manufacturing a metal mask by a metal mask material by etching or the like, the defective metal mask is observed by visually observing the presence or absence of a defect of the surface of the metal mask material by a CCD camera or the like. The material is removed from the step.

Further, the vapor deposition material that has not been reached on the substrate and is shielded from the portion other than the opening of the metal mask is deposited, but is washed and used as a metal mask. Regarding the presence or absence of defects in the surface of the metal mask thus used repeatedly, the defective metal mask is removed from the step by visual inspection or monitoring by a CCD camera or the like.

Examples of the defects of the metal mask include foreign matter adhering to the surface, partial discoloration, and poor glossiness. The image obtained by magnifying the surface by a CCD camera or the like is used to check the microscopic defects that cannot be confirmed by visual observation. By. Among the defects, foreign matter and partial discoloration different from the color of the metal mask material can be easily detected. Moreover, foreign matter such as a metal sheet having the same color tone as the metal mask material becomes difficult to be inspected compared to a foreign matter having a different color tone or partial discoloration. found out. Further, the partial gloss defect is unclear, and the color tone is the same as that of the metal mask material, so that it is further difficult to recognize on the CCD camera image.

Therefore, if the unevenness and the pattern of the surface of the metal mask material are conspicuous, the slight and weak defects such as the partial gloss failure described above are difficult to be detected in the visual inspection, and there is a possibility that the image cannot be detected even if it is a CCD camera image. In this technique, in the technique described in Patent Document 4, the surface roughness is appropriately increased to improve the etching precision. However, due to the unevenness of the surface, the partial gloss is accurately detected by the CCD camera image. The aspect of badness is not sufficient.

Therefore, an object of the present invention is to provide a metal mask material and a metal mask which can improve the accuracy of etching processing and can accurately detect defects of themselves.

As a result of intensive research, the present inventors have found that by controlling the 60-degree gloss G60 within a specific range, it is possible to improve the etching processing accuracy and to provide appropriate surface unevenness capable of accurately detecting defects of itself.

That is, the metal mask material of the present invention is composed of a rolled plate of an Fe-Ni alloy, and the rolled plate of the Fe-Ni alloy contains a total of 30 to 45 mass% of Ni and Co, and 0 to 6 mass% of Co. And the remaining portion is composed of Fe and unavoidable impurities, and the thickness t of the metal mask material exceeds 0.08 mm, and the arithmetic mean roughness Ra measured according to JIS-B0601 in the direction parallel to the rolling and the direction perpendicular to the rolling direction It is 0.01 to 0.20 μm, and the 60-degree gloss G60 measured in accordance with JIS-Z8741 in the direction parallel to the rolling and the direction perpendicular to the rolling is 200 to 600.

Further, the metal mask of the present invention is formed using the above-described metal mask material.

According to the present invention, it is possible to provide a metal mask material and a metal mask which can improve the etching processing accuracy and can accurately detect defects of itself.

G‧‧‧ grain

RD‧‧‧ rolling direction

Fig. 1 is a view showing an optical microscope image of a pattern caused by grain division after finish rolling.

Hereinafter, a metal mask material according to an embodiment of the present invention will be described. In addition, unless otherwise indicated, "%" means "mass%".

(alloy composition)

In the substrate of the organic EL, glass is used, and the alloy composition must be adjusted so that the thermal expansion coefficient of the metal mask provided on the substrate is 10×10 ^-6 /° C. or less. The thermal expansion coefficient can be adjusted by adding a specific concentration of Ni and/or Co to Fe to form an Fe-Ni-based alloy in which Ni and Co are 30 to 45% in total and Co is set to 0 to 6%. If the total concentration of Ni and Co and the concentration of Co deviate from the range, the thermal expansion coefficient of the metal mask becomes larger than the thermal expansion coefficient of the glass, which is uncomfortable. Preferably, Ni and Co are set to be 34 to 38% in total, and Co is set to 0 to 6%.

(thickness)

The thickness of the metal mask material of the present invention exceeds 0.08 mm, preferably 0.08 to 0.25 mm, more preferably 0.10 to 0.20 mm. If the thickness of the metal mask material is 0.08 mm or less, there is a case where the metal mask is easily strained or deformed due to the accumulation of the organic material, thereby forming The positional accuracy of the organic material on the substrate is poor. If the thickness of the metal mask material exceeds 0.25 mm, there is a case where a so-called shadow effect is apparently generated: the incident angle of the organic material becomes shallower at a position away from the vapor deposition source, and the wall of the opening portion becomes a shadow, and the pattern of the organic material is The shape is shaped differently from the opening portion, and it becomes difficult to maintain the shape accuracy.

(arithmetic mean roughness Ra)

The arithmetic mean roughness Ra measured in accordance with JIS-B0601 in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction of the metal mask material of the present invention is 0.01 to 0.20 μm, preferably 0.01 to 0.08 μm. If Ra is less than 0.01 μm and the surface roughness is excessively lowered, the surface is smooth, so that a material guiding roller (through foil roll, through-roller) which is formed by etching a metal mask from a metal mask material is formed. Sliding is prone to scars. Further, when the Ra exceeds 0.20 μm and the surface roughness is excessively thick, the outline is unclear, and it becomes difficult to recognize the partial gloss defect of the same color tone and the metal mask material on the CCD camera image.

Further, the maximum height Ry of the surface of the metal masking material of the present invention measured in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction is preferably 0.1 to 2.0 μm in accordance with JIS-B0601.

(60 degree gloss G60)

The 60-degree gloss G60 measured in accordance with JIS-Z8741 in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction of the metal mask material of the present invention is 200 to 600, preferably 400 to 600. If the G60 of the metal mask material is less than 200, the unevenness and pattern of the surface are conspicuous, the outline is unclear, and it becomes difficult to detect the partial gloss defect of the same color tone and the metal mask material on the CCD camera image. If the G60 of the metal mask material exceeds 600, the surface becomes too smooth, so due to surface control factors (such as the shape or surface roughness of the roll, the viscosity of the rolled oil, the surface formed on the roll and the metal mask) The thickness of the oil film between the surfaces of the material, and the metal mask material before rolling The influence of the unevenness of the surface roughness) greatly changes the G60, and it becomes difficult to ensure uniformity of the surface, and it is easy to cause poor quality (for example, streaks or unevenness).

(Manufacturing method of metal mask material)

The metal mask material of the present invention can be produced, for example, as follows, but is not intended to be limited to the method shown below.

First, the raw material is melted by a melting furnace to obtain a melt composed of the above Fe-Ni-based alloy. In this case, when the oxygen concentration of the melt is high, there is a case where the amount of formation of crystals such as oxide increases, which causes a problem of etching failure. Therefore, a general deacidification method is used, for example, carbon is added and vacuum induction is performed. After melting, etc., the cleanliness of the melt is increased and then cast into an ingot. Then, after hot rolling and polishing of the oxide layer, it is subjected to cold rolling and annealing to be finished to a specific thickness. Cold rolling and annealing may be carried out, for example, in the steps of intermediate recrystallization annealing, intermediate cold rolling, final recrystallization annealing, finishing cold rolling, and relaxation annealing.

(intermediate recrystallization annealing)

It is preferable to carry out recrystallization annealing of 9.0 to 11.0 in the crystal grain size number GSNO. (the number specified in JIS G 0551 "Microscope test method for steel-crystal grain size"). The metal structure aligned in the final recrystallization annealing (200) can be obtained by increasing the crystal grain size number GSNO. In the final recrystallization annealing, the (200) aligned metal structure is difficult to produce a crystal grain breaking pattern in the finish cold rolling, and the 60 degree gloss G60 is surely 200 or more. When the crystal grain size number GSNO. is small, that is, if the crystal grain size is large, there is a case where the metal structure which is sufficiently aligned in the final recrystallization annealing (200) cannot be obtained. Therefore, the lower limit of the crystal grain size number GSNO. is 9.0. On the other hand, if the crystal grain size number GSNO. is too large, that is, if the crystal grains are too small, the unrecrystallized portion is dispersed in the recrystallized structure, resulting in unevenness in the final recrystallization annealing. The reason for recrystallizing the structure was such that the upper limit of the crystal grain size number GSNO. was set to 11.0.

Here, when the temperature or the extension time of the intermediate recrystallization annealing is increased, GSNO. becomes small, and when the temperature is lowered or the time is shortened, GSNO. becomes large.

(intermediate cold rolling)

It is preferable to carry out cold rolling in which the degree of work defined by the following formula is 85% or more.

Processing degree = {(thickness before rolling; thickness after rolling) / (thickness before rolling)} × 100 (%)

By increasing the degree of processing, a metal structure (200) aligned in the final recrystallization annealing can be obtained, and as described above, the 60 degree gloss G60 becomes high. When the degree of processing is small, there is a case where a metal structure which is sufficiently aligned in the final recrystallization annealing (200) cannot be obtained, so the lower limit of the degree of work is set to 85%. On the other hand, even if the degree of processing is too high, the degree of orientation of (200) in the final recrystallization annealing is not further increased, and the hardness is increased and the productivity is lowered. Therefore, the upper limit of the degree of processing is set to 90%.

(final recrystallization annealing)

When the recrystallization annealing of the crystal grain size number GSNO. is 9.0 to 11.0 in the final recrystallization annealing, the 60-degree gloss G60 can be surely 200 or more for the same reason as in the case of the intermediate recrystallization annealing.

(finishing cold rolling)

The surface properties (arithmetic mean roughness Ra and 60 degree gloss G60) of the metal mask material vary depending on the surface unevenness generated in the finish cold rolling. In the finishing cold rolling, the rolling roll is transferred onto the material to cause surface irregularities. Further, surface irregularities are generated by injecting oil into the rolling oil between the rolling rolls and the material in the finish cold rolling. That is, there is an oil film between the rolling roll and the material, and in the thick portion of the oil film, the contact between the rolling roll and the material becomes insufficient, and The transfer roll is rolled to form a pit-like irregularity, which becomes an oil sump. The reason why the rolling oil is partially thickened is the unevenness of the surface of the rolling roll and the unevenness of the workability of the material. In particular, when the surface is smooth, the sensitivity of the influence of the unevenness is increased, and the thickness of the oil film is likely to be uneven.

Further, in the finish cold rolling, crystal grains are broken and a pattern is generated, which greatly affects the 60 degree gloss G60.

Fig. 1 shows an optical microscope image of a pattern caused by grain breakage after finishing cold rolling. The pattern of the grain division is intermittently distributed in a row along the rolling direction RD, and each pattern has a stripe shape extending in a direction crossing the rolling direction RD as indicated by an arrow in FIG. Further, in Fig. 1, two (2 lines) clear patterns are generated along the rolling direction RD.

Here, the symbol G in Fig. 1 indicates an elliptical one crystal grain which is extended in the rolling direction RD in cold rolling. It can be seen that the breaking pattern is generated inside the crystal grain G.

Furthermore, in Fig. 1, the focus of the optical microscope image is aligned with the grain-dividing pattern, so that the surface unevenness of the oil pit or the rolling roller pattern, which is different in focus position from the crystal grain breaking pattern, is not The picture is shown in Figure 1.

From the viewpoint of productivity, the cold rolling of the sheet is performed at a high degree of work, so that the crystal grains are extended long and are easily broken. The divided grains are rendered as a pattern on the surface as shown in Fig. 1, resulting in a decrease in the 60 degree gloss G60.

Here, the ease of occurrence of the division of the crystal grains is affected by the alignment of the crystal grains, and the ease of separation depends on the alignment of the crystal grains. Its ability to deform due to crystallization differs depending on the crystal orientation. Moreover, the main diffraction peaks of the alloy of the metal mask material of the present invention are (200) plane, (220) plane, (311) plane and (111) plane, but the (200) plane grain is the most difficult to divide. Broken. Therefore, as described above, it becomes refined by cold rolling in the intermediate recrystallization annealing and the final recrystallization annealing in the (200) plane alignment. It is difficult to produce grain breakage, and the 60 degree gloss G60 can be made 200 or more.

It is preferable to set the degree of finishing cold rolling to 70% or more. The higher the degree of processing, the smaller the breaking pattern of the crystal grains generated in the finish cold rolling by the effect of the compression processing, and the higher the 60-degree gloss G60. On the other hand, even if the degree of processing is too high, the effect of weakening the pattern of the crystal grains due to the compression processing is saturated, and the hardness is increased and the productivity is lowered. Therefore, the upper limit of the degree of processing is set to 90%. .

Here, by cold rolling using a rolling roll having as small a diameter as possible, the rolling of the rolling oil is reduced, and the surface of the rolled material is smoothed. That is, in the case of using a small-diameter rolling roll, the generation of the oil crater can be suppressed, and the division pattern of the crystal grains can be reduced. Further, similarly to the diameter of the rolling roll, by setting the rolling speed to a low speed, the rolling of the rolling oil is reduced, and the surface of the rolled material is smoothed. That is, when the rolling speed is set to a low speed, the generation of the oil crater can be suppressed, and the crystal grain division pattern can be reduced.

Furthermore, the roll diameter and the rolling speed of the cold rolling roll are varied depending on the thickness or width of the metal mask material to be produced, and the roll diameter of the roll is appropriately set within the range of controllable Ra and G60. The rolling speed may be set, and the rolling speed may be set to 60 m/min or less.

Further, since the oil pit and the crystal grain breaking pattern are respectively caused by different factors, it is preferable to confirm the production condition of the oil pit and the crystal grain breaking pattern while setting the conditions, and the manufacturing conditions of both can be suppressed.

(slow annealing)

Further, it is preferred to carry out the relaxation annealing at 200 to 400 ° C at the end. The relaxation annealing time can be, for example, 1 to 24 hours.

[Examples]

Hereinafter, embodiments of the present invention are shown, but these are for better understanding of the present invention. It is intended to be illustrative, and is not intended to limit the invention.

(1) Manufacture of metal mask materials

The raw material obtained by adding 36% by mass of Ni to Fe was melted by vacuum induction melting, and an ingot having a thickness of 50 mm was cast. After hot rolling to 8 mm, the oxide film on the surface was polished and removed, and then cold rolling and annealing were repeated to form a cold rolled material, and then intermediate recrystallization annealing and intermediate cold rolling were sequentially performed under the conditions shown in Table 1. The steps of final recrystallization annealing, finishing cold rolling, and finishing were the metal mask materials of the product thicknesses of Examples 1 to 8 and Comparative Examples 1 to 4 of Table 1. Further, relaxation annealing was performed at 300 ° C for 12 hours. Further, as a composition of Example 9, a composition in which 31% by mass of Ni and 5% by mass of Co were added to Fe was produced. The manufacturing steps of Example 9 were the same as in the other examples.

Further, the crystal grain size number GSNO. in the intermediate recrystallization annealing was set to 10.0. Further, the surface roughness of the rolling rolls was adjusted for each of the examples so that the arithmetic mean roughness Ra of the surface of the product was 0.07 to 0.08 (0.065 to 0.084).

The following evaluations were performed on the metal mask materials of the respective examples and comparative examples after the relaxation annealing.

(1) Arithmetic mean roughness Ra

The measurement was carried out as described above. For the measurement, a contact surface roughness meter (SE-3400 manufactured by Kosaka Research Institute) was used, and the average value measured by n≧3 was determined.

(2) 60 degree gloss G60

The measurement was carried out as described above. The measurement was performed using a HANDI type gloss meter PG-1 manufactured by Nippon Denshoku Industries Co., Ltd., and the average value measured by n≧3 was obtained.

(3) Whether the surface defects are incorrectly measured

For each of the metal mask materials of the respective examples and comparative examples, surface defects of five stages were intentionally made, and surface defects were measured by a CCD camera.

Specifically, an acid-resistant tape of 50 mm × 50 mm was attached to the surface of each metal mask, and an opening of 10 mm × 10 mm was provided in the center thereof to partially expose the surface. The following five kinds of etching liquids were applied to the exposed portions to form surface irregularities to form surface defects. Regarding the exposed portion, the state of blurring can be confirmed by visual observation as compared with the surroundings, and this is regarded as a surface defect serving as a reference.

The etchant system is used by directly using the aqueous solution of 47 Bomei iron(III) chloride and diluting it to 2 times, 4 times, 8 times, and 16 times with water, and supporting the absorbent cotton impregnated with the etching liquid by using tweezers. Etching was performed by rubbing the exposed portion of the absorbent cotton for 15 seconds. After the etching, the etching liquid was wiped by a cloth impregnated with water, and the acid-resistant tape was peeled off to complete the work. Further, in the case where the iron chloride (III) aqueous solution is not diluted and used for etching, the metallic luster of the exposed portion is completely lost and white, and as the dilution ratio is increased, the blur of the exposed portion is weakened. Further, when the dilution ratio was 32 times, the blurring of the exposed portion was not confirmed by visual observation, and therefore, it was considered that no surface defect was formed, and the dilution ratio was 16 times. Therefore, in the etching by the above five etching liquids, surface defects which can be confirmed by visual observation are formed, and if it is not affected by the surface unevenness of the metal masking material, it is originally detected by the CCD as a surface defect.

Next, regarding the above five kinds of surface defects, 256 gray scale (±128) pixel data was taken by a CCD camera. Here, the state in which the reflected light is blocked is set to the darkest reflection and set to a brightness of -128, and the reflection from the regular portion (the portion around the exposed portion) in the surface of the metal mask is set to ± 0. Moreover, the reflection controlled in the range of luminance ± 20 is defined as the normal reflection in the normal portion, and the reflection in the range deviating from the luminance ± 20 is defined as the abnormal reflection of the surface defect, and It is confirmed at the exposed portion whether or not the abnormal reflection can be detected.

In the case of the metal mask of each of the examples and the comparative examples, the above-mentioned five types of surface defects were all detected as "no erroneous measurement of surface defects", and one or more of the five types of surface defects could not be detected. The case was judged as "false measurement of surface defects".

As is clear from Table 1, in the case of each of Examples in which Ra was 0.01 to 0.20 μm and G60 was 200 to 600, no erroneous measurement of surface defects occurred.

On the other hand, in the case of Comparative Example 1 in which the degree of processing of finishing cold rolling is less than 70%, and the case of Comparative Example 2 in which the rolling speed of finishing cold rolling exceeds 60 m/min, the G60 is less than 200, and surface defects are generated. Mistaken determination.

In the case of Comparative Example 3 in which the final recrystallization annealing was carried out under the condition that the crystal grain size (GSNo.) of the final recrystallization annealing was less than 9.0, and the case of Comparative Example 4 in which the degree of processing of the intermediate cold rolling was less than 85%. At the same time, the G60 did not reach 200, causing an erroneous measurement of surface defects.

G‧‧‧ grain

RD‧‧‧ rolling direction

Claims (2)

A metal mask material comprising a rolled plate of an Fe-Ni alloy, the rolled plate of the Fe-Ni alloy containing a total of 30 to 45 mass% of Ni and Co, and 0 to 6 mass% of Co, and The remaining portion is composed of Fe and unavoidable impurities; the thickness of the metal mask material exceeds 0.08 mm, and the arithmetic mean roughness Ra measured according to JIS-B0601 in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction is 0.01. ~0.20 μm, and the 60-degree gloss G60 measured according to JIS-Z8741 in the direction parallel to the rolling and the direction perpendicular to the rolling is 200 to 600. A metal mask using the metal mask material of claim 1 of the patent application.