Metal mask original material and processing technology

Abstract

The present invention discloses a metal mask original material and a processing technology. In terms of mass%, Si% < 0.01, Al% < 0.01, Mg% < 0.001, O% < 0.001, 0.2 < Mn% < 0.4, 35.5 < Ni% < 36.5, and the rest is Fe and inevitable substances, and 0.5 ≤ Si% / Al% ≤ 5. By controlling the silicon-aluminum ratio and the content of corresponding oxides in the metal mask original material, the number of oxides is significantly reduced, the large-size oxides are greatly reduced, and the defective rate related to hole breakage is sharply reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a raw material for a metal mask plate and a processing technology thereof. Background Art

[0002] For example, in the production of an organic electroluminescence (EL) display, a metal mask is used to vapor-deposit a substrate to generate a color pattern. In the prior art, a thin plate of Fe-Ni alloy is generally used as the base material of the metal mask. However, if there are a large number of oxides in the thin plate of the Fe-Ni alloy, the etching process becomes uneven, resulting in impaired etching accuracy. For example, in the Korean patent with the publication number KR100263618B1, it contains a large amount of MnO-SiO2 type oxides, which have a low melting point, soft texture, and are easy to break. However, this type of oxide has a large number and is easy to agglomerate, and is likely to form chain-like pits or pits (impurities and foreign objects) during hot processing and cold processing, affecting the etching accuracy and easily causing defects such as FMM punching; in the Chinese patent with the publication number CN109715834A, it mainly contains spinel-based oxide inclusions of the Al-Mg-O system (MgO·Al2O3 system) of the oxide system, which is relatively softer than Al2O3 in texture. By applying plastic deformation to the raw material through a rolling step or the like, it is possible to promote micro-refinement through crushing and breaking. However, this type of inclusion has a large number and is easy to agglomerate, and is likely to form chain-like pits or pits after rolling, affecting the etching accuracy and causing FMM punching defects; in the Japanese patent with the publication number JP2002206144A, the composition of the inclusions is controlled to be based on MnO-SiO2-Al2O3-CaO-MgO-FeO, but this type of inclusion has a large number, large size, and is easy to agglomerate, and is likely to form chain-like pits or pits after rolling, affecting the etching accuracy and causing FMM punching defects. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a raw material for a metal mask plate. By controlling the silicon-aluminum ratio and the content of corresponding oxides in the raw material for the metal mask plate, the number of oxides is significantly reduced, the large-size oxides are significantly reduced, and the defective rate related to punching is sharply reduced.

[0004] The present invention adopts the following technical solutions:

[0005] A raw material for a metal mask plate, in terms of mass%, Si% < 0.01, Al% < 0.01, Mg% < 0.001, O% < 0.001, 0.2 < Mn% < 0.4, 35.5 < Ni% < 36.5, and the rest is Fe and inevitable substances, and 0.5 ≤ Si% / Al% ≤ 5.

[0006] Preferably, the unavoidable substances are: C, P, S, Pb, Sn, As, Sb, Bi, N, and H elements, wherein C%<0.01, P%<0.003, S%<0.001, Pb%<0.001, Sn%<0.001, As%<0.001, Sb%<0.001, Bi%<0.001, N%<0.0005, and H%<0.0003.

[0007] Preferably, in each cubic millimeter, the number of L≥5um is ≤80; the number of 10um≤L<20um is ≤10; the number of L≥20um is =0, wherein L is the size of the oxide.

[0008] Preferably, the oxide is SiO2, Al2O3, Al2O3·SiO2, Al2O3·MgO, or MgO.

[0009] Preferably, the SiO2<20%, Al2O3<20%, Al2O3·MgO<10%, MgO<10%, and the rest is Al2O3·SiO2.

[0010] Preferably, the Al% is less than 0.005.

[0011] Preferably, the O%<0.0005.

[0012] A metal mask raw material processing process comprises a VIM+PESR+VAR smelting process for high-purity iron and high-purity nickel; the VIM process: smelting vacuum degree <5Pa, vacuum degree at the end of refining <0.5Pa; VIM ingot oxygen content 0%≤15ppm; the PESR process: argon protective atmosphere; filling ratio 0.5-0.8; current (kA) 9-14.5; voltage (V) 55-60; electroslag slag CaF2%: Al2O3%: CaO%=50%-70%: 10%-20%: 10%-20%; PESR ingot oxygen content 0%≤15ppm; the VAR process: smelting vacuum degree <0.5Pa; filling ratio 0.6-0.9; melting speed <5kg / min; helium cooling; VAR ingot oxygen content 0%≤5ppm.

[0013] Preferably, the method comprises the following steps: 1) vacuum melting: VIM+PESR+VAR or VIM+PESR+VAR+VAR; 2) forging: forging at 1100°C to 1200°C; 3) hot rolling: heating temperature is in the range of 1050°C to 1250°C, hot rolling is performed after keeping the temperature for 1 to 5 hours; 4) solution annealing: solution annealing is performed at a heating temperature in the range of 800°C to 1100°C; 5) cold rolling rough rolling: total reduction rate is above 90% to 95%, at least 2 to 3 rolling passes, and the last rolling pass is reduced by 10% to 15%; Amount> 50% ~ 85%; 6) Intermediate softening annealing: heat treatment temperature 700 ℃ ~ 1050 ℃, heat treatment time 30 seconds ~ 150 seconds, at least 2 times or more of intermediate softening annealing during rough rolling; 7) Cold rolling and finishing rolling: the total rolling rate of the rolling process is preferably more than 70%, and the number of rolling passes in the cold rolling is preferably more than five times; 8) Straightening: 0.2% ~ 0.7% elongation; 9) Stress relief annealing process: the temperature is about 400 ℃ ~ 700 ℃, and the annealing time is preferably set to about 0.5min ~ 2.0min.

[0014] Preferably, the method for detecting the quantity and size of oxides in the metal mask original material is: extracting the oxides in the original material with a mixed acid, and confirming the quantity and composition of the oxides with a SEM.

[0015] Compared with the prior art, the present invention has the following advantages: the present invention provides a metal mask original material, which controls the silicon-aluminum ratio and the content of corresponding oxides in the metal mask original material, thereby greatly reducing the number of oxides, greatly reducing large-size oxides, and sharply reducing the defective rate related to pores. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 AOI and SEM photos of the Invar cold-rolled thin strip sample with single-side thinning of 1.5 μm.

[0017] Figure 2 It is the EDS component analysis diagram of chain Pit or Pit.

[0018] Figure 3 These are AOI and SEM photos of chain-shaped pits or hole defects caused by pits on FMM.

[0019] Figure 4 This is the EDS composition analysis diagram of the chain pit or the hole area caused by pit.

[0020] Figure 5 The figure is a process flow chart of the metal mask raw material processing of the present invention. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the technical solution of the present invention, a detailed description is given below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] In the prior art, a thin sheet of Fe-Ni alloy is generally used as the base material of the metal mask. However, if there are a large number of oxides in the thin sheet of Fe-Ni alloy, the etching process becomes uneven, resulting in impaired etching accuracy.

[0024] Since the impurity foreign matters are present inside the metal material, the impurity foreign matters cannot be seen on the original surface of the INVAR thin strip. In order to better show that the chain-shaped Pit or Pit (impurity foreign matter) is likely to cause the FMM hole-breaking defect, in this embodiment, the metal material is etched off by 1.5 microns on one side through chemical etching to observe the impurity foreign matters shown on the etched surface. Figure 1 AOI photos and SEM photos of the sample with the cold-rolled thin strip thinned by 1.5 microns on one side. Among them, Figure 1 a is the AOI photo of the Pit on the INVAR thin strip, Figure 1 b is the AOI photo of the chain-shaped Pit on the INVAR thin strip, Figure 1 c-d are the SEM photos of the chain-shaped Pit on the INVAR thin strip.

[0025] Perform EDS composition analysis on the chain-shaped Pit or Pit, and obtain the Figure 2 EDS composition analysis diagram of the chain-shaped Pit or Pit as shown, indicating that the chain-shaped Pit or Pit is mainly silicon oxide and magnesium oxide.

[0026] As Figure 3 shown, process the INVAR thin strip into FMM and then conduct detection, and it can be concluded that the chain-shaped Pit or PIt will cause the hole-breaking defect to the FMM.

[0027] As Figure 4 shown, perform EDS composition analysis on the chain-shaped Pit or Pit on the FMM, and obtain the Figure 4 EDS composition analysis diagram of the chain-shaped Pit or Pit as shown, indicating that the chain-shaped Pit or Pit is mainly silicon oxide and magnesium oxide.

[0028] For the above reasons, the present invention provides a raw material for a metal mask plate. In terms of mass%, Si% < 0.01, Al% < 0.01, Mg% < 0.001, O% < 0.001, 0.2 < Mn% < 0.4, 35.5 < Ni% < 36.5, the rest is Fe and inevitable substances, and 0.5 ≤ Si% / Al% ≤ 5.

[0029] The present invention uses a processing technology to control the content of each element in the metal mask blank, especially the content of oxygen element, so as to control the content of its oxides. Specifically, in this embodiment, the content of oxygen element is reduced to less than 0.001%, the content of Si is reduced to 0.01%, the content of Al is reduced to 0.01%, and 0.5 ≤ Si% / Al% ≤ 5. Under this condition, the large-size oxides are significantly reduced, and the defective rate related to hole breakage is sharply reduced compared with the prior art.

[0030] Specifically, the inevitable substances are: C, P, S, Pb, Sn, As, Sb, Bi, N, H elements. Among them, C% < 0.01, P% < 0.003, S% < 0.001, Pb% < 0.001, Sn% < 0.001, As% < 0.001, Sb% < 0.001, Bi% < 0.001, N% < 0.0005, H% < 0.0003.

[0031] Under the above conditions, in each cubic millimeter, the number of L ≥ 5um ≤ 80; the number of 10um ≤ L < 20um ≤ 10; the number of L ≥ 20um = 0, where L is the size of the oxide. From the above data, it can be seen that the large-size oxides are significantly reduced.

[0032] In this embodiment, the oxides are SiO2, Al2O3, Al2O3·SiO2, Al2O3·MgO, MgO. The SiO2 < 20%, Al2O3 < 20%, Al2O3·MgO < 10%, MgO < 10%, and the rest is Al2O3·SiO2. In the following table, Example 1 and Example 2 are the metal mask blanks prepared according to the processing technology of the present invention, and this blank meets the above requirements. Comparative Example 1 and Comparative Example 2 are the implementation methods in the prior art. Through the comparison experiment data of Example 1 and Example 2 with Comparative Example 1 and Comparative Example 2, it can be obtained that when Si% < 0.01, Al% < 0.01, Mg% < 0.001, O% < 0.001, 0.2 < Mn% < 0.4, 35.5 < Ni% < 36.5, and 0.5 ≤ Si% / Al% ≤ 5, the defective rate related to hole breakage of the metal mask blank is significantly reduced, and the quality of the metal mask blank is greatly improved.

[0033]

[0034] It can be concluded from the above two tables that when 0.5 ≤ Si% / Al% ≤ 5, the lower the content of Al and O, the lower the defective rate related to hole breakage.

[0035] As Figure 5 shown, in this embodiment, the processing technology of the metal mask blank includes the following steps:

[0036] 1) Vacuum melting: VIM+PESR+VAR or VIM+PESR+VAR+VAR;

[0037] 2) Forging: 1100℃~1200℃ forging;

[0038] 3) Hot rolling: The heating temperature is within the range of 1050°C to 1250°C, and hot rolling is performed after keeping the temperature for 1 to 5 hours;

[0039] 4) Solution annealing: solution annealing at a heating temperature in the range of 800°C to 1100°C;

[0040] 5) Cold rolling and rough rolling: the total reduction rate is more than 90% to 95%, at least 2 to 3 rolling passes, and the reduction of the last rolling pass is >50% to 85%;

[0041] 6) Intermediate softening annealing: heat treatment temperature 700℃~1050℃, heat treatment time 30s~150s, at least 2 or more intermediate softening annealings are performed during the rough rolling process;

[0042] 7) Cold rolling and finishing: the total rolling rate of the rolling process is preferably 70% or more, and the number of cold rolling passes is preferably five or more;

[0043] 8) Tensile correction: 0.2% to 0.7% elongation;

[0044] 9) Stress relief annealing process: the process is carried out at a temperature of about 400° C. to 700° C., and the annealing time is preferably set to about 0.5 min to 2.0 min.

[0045] The vacuum smelting process includes a VIM+PESR+VAR smelting process for high-purity iron and high-purity nickel. In this embodiment, the oxides of aluminum and silicon are removed by dynamics (gravity flotation, slag absorption, etc.), and the removal of oxygen is mainly by VIM and VAR vacuum smelting, such as the removal of CO by the reaction of oxygen and carbon in a vacuum environment;

[0046] The VIM process: the melting vacuum is less than 5Pa, the vacuum at the end of refining is less than 0.5Pa; the oxygen content of the VIM ingot is 0% ≤ 15ppm;

[0047] The PESR process includes: argon protective atmosphere; filling ratio 0.5-0.8; current (kA) 9-14.5; voltage (V) 55-60; electroslag slag CaF2%: Al2O3%: CaO% = 50%-70%: 10%-20%: 10%-20%; PESR ingot oxygen content O% ≤ 15ppm;

[0048] The VAR process: melting vacuum degree <0.5Pa; filling ratio 0.6-0.9; melting speed <5kg / min; helium cooling; VAR ingot oxygen content 0% ≤ 5ppm, wherein the filling ratio is the melting electrode diameter / crystallizer inner diameter.

[0049] As a preferred embodiment, the vacuum smelting process includes performing a VIM+PESR+VAR+VAR smelting process on high purity iron and high purity nickel.

[0050] The method for detecting the number and size of oxides in the metal mask raw material is: using mixed acid to extract the oxides in the raw material, and using SEM to confirm the number and composition of the oxides.

[0051] The above are only preferred embodiments of the present invention. The protection scope of the present invention shall be based on the scope defined by the claims. Several improvements and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A metal mask original material, characterized in that: In mass percentage, Si% < 0.01, Al% < 0.01, Mg% < 0.001, O% < 0.001, 0.2 < Mn% < 0.4, 35.5 < Ni% < 36.5, the balance being Fe and unavoidable substances, and 0.5 ≤ Si% / Al% ≤ 5; In each cubic millimeter, the number of L ≥ 5um ≤ 80; The number of 10um ≤ L < 20um ≤ 10; the number of L ≥ 20um = 0, where L is the size of the oxide; The oxides are SiO2, Al2O3, Al2O3·SiO2, Al2O3·MgO, MgO; The proportion of the number of the oxides is: SiO2 < 20%, Al2O3 < 20%, Al2O3·MgO < 10%, MgO < 10%, and the rest is Al2O3·SiO2; The Al% < 0.005; The O% < 0.0005.

2. The metal mask original material according to claim 1, characterized in that: The unavoidable substances are: elements C, P, S, Pb, Sn, As, Sb, Bi, N, H, where C% < 0.01, P% < 0.003, S% < 0.001, Pb% < 0.001, Sn% < 0.001, As% < 0.001, Sb% < 0.001, Bi% < 0.001, N% < 0.0005, H% < 0.0003.

3. A metal mask original material processing process for processing the metal mask original material according to any one of claims 1-2, characterized in that: It includes a melting process of VIM + PESR + VAR for high-purity iron and high-purity nickel; The VIM process: the melting vacuum degree < 5Pa, the vacuum degree at the end of refining < 0.5Pa; the oxygen content O% of the VIM ingot ≤ 15ppm; The PESR process: argon protection atmosphere; filling ratio 0.5 - 0.8; current 9 - 14.5kA; voltage 55 - 60V; the ratio of the electro-slag materials CaF2%:Al2O3%:CaO% = 50% - 70%:10% - 20%:10% - 20%; the oxygen content O% of the PESR ingot ≤ 15ppm; The VAR process: the melting vacuum degree < 0.5Pa; filling ratio 0.6 - 0.9; melting speed < 5kg / min; helium cooling; the oxygen content O% of the VAR ingot ≤ 5ppm.

4. The metal mask raw material processing process according to claim 3, characterized in that: It includes the following steps: 1) Vacuum melting: VIM + PESR + VAR or VIM + PESR + VAR + VAR; 2) Forging: forging at 1100°C to 1200°C; 3) Hot rolling: heating temperature in the range of 1050°C to 1250°C, hot rolling after holding for 1 to 5 hours; 4) Solution annealing: solution annealing with the heating temperature in the range of 800°C to 1100°C; 5) Cold rolling rough rolling: total reduction ratio 90% - 95% or more, at least 2 - 3 rolling passes, and the reduction in the last rolling pass > 50% - 85%; 6) Intermediate soft annealing: heat treatment temperature 700°C to 1050°C, heat treatment time 30 seconds to 150 seconds, and at least 2 times or more of intermediate soft annealing during the rough rolling process; 7) Cold rolling finish rolling: the total rolling rate of the rolling process is 70% or more, and the number of rolling passes in cold rolling is more than five; 8) Stretch leveling: elongation 0.2% - 0.7%; 9) Stress relief annealing process: carried out at a temperature of 400°C to 700°C, and the annealing time is 0.5min to 2.0min.

5. The metal mask raw material processing process according to claim 4, characterized in that: The method for detecting the number and size of oxides in the metal mask raw material is: using mixed acid to extract the oxides in the raw material, and using SEM to confirm the number and composition of the oxides.

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