CROSS-REFERENCE TO RELATED APPLICATION(S)

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2018-0139333, filed on Nov. 13, 2018, in the Korean Intellectual Property Office; the entire contents of the Korean Patent Application are incorporated by reference.

BACKGROUND

The technical field relates to a method of etching a substrate for manufacturing a mask.

In general, an organic light emitting diode (OLED) display device includes an organic light emitting element for emitting light through an electrical excitation process. The organic light emitting element typically has a multi-layered structure including an emitting layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL). In certain cases, the organic light emitting element may further include an electron Injection layer (EIL) and a hole injection layer (HIL).

The organic light emitting element is typically fabricated through a deposition process. A fine metal mask (FMM) is used in the deposition process. The fine metal mask includes a mask patterns formed by a chemical etching process, a plating-based patterning process, and/or a laser etching process.

SUMMARY

An embodiment may be related a method of producing a mask for optimizing a yield of organic light emitting element manufacturing and/or display device manufacturing.

According to an embodiment, a method of etching a substrate may include preparing a target substrate, the target substrate including a plurality of hole regions and a blocking region enclosing the hole regions, when viewed in a plan view, forming a first coating layer, which has an optically transparent property, on the target substrate, forming a scattering layer between the first coating layer, which is overlapped with the blocking region in a plan view, and the target substrate, and etching the hole, regions of the target substrate to form a plurality of mask holes.

In an embodiment, the method may further include patterning the first coating layer, after the foraging of the first coating layer. The patterned first coating layer may be overlapped with the blocking region and may be not overlapped with the hole regions in a plan view.

In an embodiment, the forming of the scattering layer may include producing particles on the target substrate by irradiating the target substrate with a first laser and then removing the particles from the hole regions. The particles on the blocking regions may be covered with the first coating layer.

In an embodiment, the producing of the particles on the target substrate may be performed to irradiate the first laser onto an entire region of the hole and blocking regions.

In an embodiment, the producing of the particles on the target substrate may he performed in such a way that a focal point of the first laser is located between the first coating layer and the target substrate.

In an embodiment, the first laser may have a diameter of about 2 μm or smatter.

In an embodiment, the first coating layer may have a thickness of about 1.5 μm or thicker.

In an embodiment, the forming of the mask holes may include irradiating the target substrate with a second laser.

In an embodiment, the second laser may have a diameter larger than the diameter of the first laser.

In an embodiment, the diameter of the second laser may be larger than or equal to about 10 μm.

In an embodiment, the first laser may have a focal length that is shorter than a focal length of the second laser.

In an embodiment, the first laser and the second laser may have a same wavelength band.

In an embodiment, the method may further include removing the first coating layer and the scattering layer, after the forming of the mask holes in the target substrate.

In an embodiment, the first coating layer may include a negative photoresist.

In an embodiment, the first coating layer may be provided in a form of a tape and may be disposed on the target substrate.

In an embodiment, the target substrate may include a metallic material.

In an embodiment, the method may further include forming a second coating layer on the scattering layer and the target substrate, after the forming of the scattering layer. The second coating layer may have an optically transparency lower than the first coating layer.

In an embodiment, the method may further include removing the first coating layer, the scattering layer, and the second coating layer, after the forming of the mask holes.

In an embodiment, the second coating layer may include positive photoresist.

According to an embodiment, a method of etching a substrate may include preparing a target substrate, the target substrate including a plurality of hole regions and a blocking region enclosing the hole regions, when viewed in a plan view, forming a first coating layer on the target substrate, the first coating layer having an optically transparent property and being overlapped with the blocking region, but not with the hole regions in a plan view, irradiating a first laser to form a scattering layer between the first coating layer, which is overlapped with the blocking region in a plan view, and the target substrate, and irradiating a second laser to etch the hole regions of the target substrate, the second laser having a diameter larger than a diameter of the first laser.

An embodiment may be related to a method manufacturing a mask may include the following steps: preparing a substrate; providing a first coating, which may be optically may cover a covered portion of the substrate, and may expose exposed portions of the substrate: forming a scattering layer between the first coating layer and the covered portion of the substrate; and removing the exposed portions of the substrate to form mask holes.

The method may include the following steps: preparing a material layer; and patterning the material layer to form the first coating.

The forming of the scattering layer may include producing particles on the substrate by irradiating the substrate with a first laser. A material of the particles may be identical to a material of the substrate. The particles may include a first particle set and a second particle set. The first particle set may be positioned on the covered portion of the substrate. The second particle set may be positioned on the exposed portions of the substrate. The for of the scattering layer may include removing the second particle set. The first particle set may be covered by the first coating. The scattering layer may include the first particle set.

The producing of the particles on the substrate may include irradiating the first laser onto both the covered portion of the substrate and the exposed portions of the substrate.

The producing of the particles on the substrate may include positioning a focal point of the first laser between the first coating and the substrate.

The first laser may have a diameter of 2 μm or smaller.

The first coating may have a thickness of 1.5 μm or thicker.

The removing of the exposed portions of the substrate may include irradiating the substrate with a second laser.

A maximum diameter of the second laser may be larger than a maximum diameter of the first laser.

The maximum diameter of the second laser may be larger than or equal to 10 μm.

A focal length of the first laser may be shorter than a focal length of the second laser.

The first laser and the second laser have a same wavelength band.

The method may include removing the first coating and the scattering removing of the exposed portions of the substrate.

The first coating may include a negative photoresist.

The first coating may include openings before the first coating is disposed on the substrate. The openings may expose the exposed portions of the substrate.

The substrate may include a metallic material.

The method may include forming a second coating on the scattering layer and the substrate after the forming of the scattering layer. An optical transparency of the second coating may be lower than an optical transparency of the first coating.

The method may include removing the first coating, the scattering layer, and the second coating after the removing of the exposed portions of the substrate.

The second coating may include a positive photoresist.

An embodiment may be related to a method for manufacturing a mask. The method may include the following steps: preparing a substrate; providing a first coating on the substrate, first coating being optically transparent, covering a covered portion of the substrate, and exposing exposed portions of the substrate; irradiating a first laser on the substrate to form a scattering layer between the first coating and the substrate; and irradiating a second laser to etch the exposed portions of the substrate. A maximum diameter of the second laser may be larger than a maximum diameter of the first laser.

