KR20110041652A - Transparent substrate for blank mask, blank mask and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A transparent substrate for a blank mask, the blank mask, and a manufacturing method thereof are provided to prevent particles from remaining on the side of the transparent substrate by forming a small groove on the side of the transparent substrate. CONSTITUTION: A transparent substrate(21) includes a main surface(23), a rear surface(24), and a lateral surface(25). A thin film(22) is deposited on the main surface. The transparent substrate includes a chamfer surface(26) between the main surface and the lateral surface or between the rear surface and the lateral surface. A groove(27) is formed on the side of the transparent substrate. The surface roughness of the transparent substrate is between 0 and 50 nm.

Description

Transparent substrate for blank mask, blank mask and manufacturing method thereof {TRANSPARENT SUBSTRATE FOR BLANK MASK, BLANK MASK AND MANUFACTURING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent substrate for a blank mask, a blank mask, and a method for manufacturing the same, and more particularly, to a transparent mask for a blank mask, a blank mask, and a method for manufacturing the same, which can reduce particles generated from the side of the transparent substrate.

Generally, a blank mask is a raw material for photomasks used in the manufacture of various semiconductor and flat panel display (FPD) devices such as liquid crystal displays, and at least one thin metal film or the like is laminated on a transparent substrate. The resist film is coated, and is produced as a photomask by selectively removing the resist film and then patterning the metal film.

The transparent substrate for the blank mask is manufactured by slicing from ingots of synthetic quartz glass (Quartz, SiO2), and then performing a plurality of lapping or polishing and cleaning processes. The major surface of the transparent substrate is manufactured to satisfy a low surface roughness Ra of 0.2 nm or less. In addition, the side surface of the transparent substrate is manufactured to have a rough surface having a surface roughness Ra of about 0.05 to 0.3 μm in order to prevent sliding during handling. (Reference 1: Korea Patent Publication No. 2004-0091058)

However, as shown in FIG. 1, since the side surface 15 of the transparent substrate 11 is made of a rough surface having a surface roughness Ra of about 0.05 to 0.3 μm, polishing is performed when manufacturing the transparent substrate. In the process, particles P such as abrasives and polishing pad residues tend to remain in the fine grooves 17 formed on the side surfaces of the transparent substrate.

Some of the particles P may be removed through a cleaning process, but some of the particles P not removed remain in the grooves 17.

The inventors of the present invention have found that the particles remaining in the grooves 17 cause an increase in the defective occurrence rate of the blank mask product in the blank mask manufacturing process, specifically, the heat treatment well.

That is, the particles P, which are not removed even by the cleaning, are hardly a problem at room temperature, but before or after the deposition of the metal film 12 on the transparent substrate 11, the deposition of the metal film 12 is performed. When the transparent substrate 11 is heat-treated at about 100 ° C. or more for the purpose of improving or stabilizing properties, the transparent substrate 11 remains in the groove 17 due to different thermal expansion coefficients of the transparent substrate and particles P, thermal decomposition of particles P, and the like. It was confirmed that the particles P that were being made were separated from the grooves 17 and adhered to the surface of the metal film 12.

This problem is caused by a rough surface having a surface roughness Ra of about 0.05 to 0.3 μm on the transparent substrate, and thus, the transparent substrate 11 as well as the side surface 15 of the transparent substrate 11. It may also occur when the chamfered surface 16 formed between the main surface 13 and the side surface 15 of the side surface, or between the back surface 14 and the side surface 15 is roughened.

On the other hand, in recent years, since the pattern is becoming finer and more precise, the necessity of minimizing particles adhering to the surface of the photomask is further increased, and in particular, for manufacturing a large-sized display device such as a TFT substrate of a liquid crystal display Since the size of the transparent substrate is larger and larger in the photomask, it is necessary to further reduce particles generated from the side of the transparent substrate before other problems.

Accordingly, an object of the present invention is to provide a high quality blank mask transparent substrate, a blank mask manufactured using the transparent substrate, and a method of manufacturing the same by reducing particles generated from the side of the transparent substrate.

The structure of the present invention for achieving the above object is characterized in that, in a blank mask transparent substrate having a main surface, a back surface and a side surface, the surface roughness Ra of the side surface of the transparent substrate is larger than 0 nm and 50 nm or less. do.

In addition, the configuration of the present invention for achieving the above object, in the transparent substrate for the blank mask having a main surface and the back and side, the transparent substrate is formed between the main surface and the side, or between the back and side surfaces. The surface roughness Ra of the side surface and the chamfered surface of the transparent substrate is greater than 0 nm and 50 nm or less.

In addition, the configuration of the present invention for achieving the above object, in the method for manufacturing a transparent mask for a blank mask having a main surface and the back and side, comprising the step of polishing the main surface, back and side of the transparent substrate. The surface roughness of the side of the polished transparent substrate is greater than 0 nm and less than 50 nm.

In addition, the configuration of the present invention for achieving the above object, in the method for manufacturing a transparent mask for a blank mask having a main surface and the back and side, between the main surface and side, or between the back and side of the transparent substrate. Forming a chamfered surface, and polishing a major surface, a back surface, a side surface, and a chamfered surface of the transparent substrate, wherein the surface roughness of the side surface and the chamfered surface of the polished transparent substrate is greater than 0 nm and 50 nm or less. It is done.

In addition, the constitution of the present invention for achieving the above object is that the surface roughness Ra of the side surface is greater than 0 nm and 50 nm or less, or the surface roughness Ra of the side surface and the chamfer surface is greater than 0 nm and 50 nm or less. Characterized in that the blank mask is formed with one or more thin films on the transparent substrate.

In addition, the constitution of the present invention for achieving the above object is that the surface roughness Ra of the side surface is greater than 0 nm and 50 nm or less, or the surface roughness Ra of the side surface and the chamfer surface is greater than 0 nm and 50 nm or less. Ultrasonic cleaning of the transparent substrate, and a method of producing a blank mask comprising the step of forming a thin film of one or more layers on the main surface of the transparent substrate.

In the transparent substrate for a blank mask according to the present invention, particles generated from the side surfaces of the transparent substrate can be reduced to manufacture a high quality blank mask and a photomask. In particular, the transparent substrate of the present invention has a greater effect of reducing particles in a large size (one side of 300 mm or more) used for manufacturing a liquid crystal display device.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Referring to FIG. 2, which shows a cross section of a blank mask according to the present invention, the transparent substrate 21 according to the present invention includes a main surface 23, a back surface 24, and a side surface 25 on which a thin film 22 is deposited. Have The transparent substrate 21 also has a major surface 23 and a side surface 25 or a chamfer 26 formed between the rear surface 24 and the side surface.

The angle formed between the major surface 23 and the side surface 25, and the rear surface 24 and the side surface 25 is about 90 degrees, and the major surface 23 and the chamfered surface 26, the rear surface 24 and the chamfered surface ( 26), and the angle between the side surface 25 and the chamfer surface 26 is about 135 °.

Although the transparent substrate 21 according to the present invention may be used in various semiconductor manufacturing photomasks, it is more preferable that the transparent substrate 21 is used in FPD manufacturing photomasks, such as a liquid crystal display device having a large size (one side of 300 mm or more). There are x 450 mm, 390 x 640 mm, 500 x 750 mm, 520 x 800 mm, 700 x 800 mm, 800 x 920 mm, 850 x 120 mm, 1220 x 1400 mm or more.

The transparent substrate 21 according to the present invention has a surface roughness Ra of the side surface 25 larger than 0 nm and 50 nm or less, so that the size of the grooves 27 formed on the side surface 25 of the transparent substrate is relatively large. By making it small, the problem that particles such as abrasives and polishing pad residues remain on the side of the transparent substrate in the polishing process of the transparent substrate is prevented at the source, and as a result, particles generated from the side surface 25 of the substrate can be minimized. have.

On the other hand, even when the surface roughness Ra of the side surface 25 of the transparent substrate is 50 nm or less, fine particles may remain. However, in this case, by cleaning the transparent substrate using a cleaning device using ultrasonic waves, it is possible to effectively remove the particles of the side surface 25 and the chamfered surface (26).

Ammonium hydroxide, hydrogen peroxide, deionized water, or the like may be used as a medium for such ultrasonic cleaning, and repeated cleaning may be performed at a frequency of 1 MHz to 5 MHz.

In the blank mask 20 of the present invention, a thin film 22 is deposited on the main surface 23 of the transparent substrate, and the thin film 22 may be an organic film or an inorganic film such as a metal film, a resist film, and one layer. Alternatively, the multilayer film may be one or more of a thin film having various functions such as a light shielding film, an antireflection film, an absorbing film, a phase shift film, and a transflective film.

The thin film 22 is preferably not formed less than 3mm from the outermost portion of the transparent substrate so that when the blank mask 20 is handled, the thin film 22 is peeled off and does not act as a particle.

When the thin film 22 is a metal film, the thin film 22 may include at least one of a metal material and O, N, C, H, F, and B, and may further contain a semiconductor material such as Si.

It is common to form a resist film on the thin film 22. The resist film functions as a mask film for patterning the thin film 22. The resist film may be coated by various methods such as spin coating or slit nozzle scan coating.

Meanwhile, before or after the thin film 22 is deposited on the transparent substrate, a process of heat treating the transparent substrate 21 may be performed for the purpose of improving or stabilizing adhesion of the thin film 22 to the transparent substrate. The heat treatment may use a hot plate, a rapid heat treatment (RTP) device with a halogen lamp, a furnace, or the like.

Hereinafter, specific embodiments according to the present invention will be described.

In the following examples, the purpose of the present invention is to examine the particle change tendency of the surface roughness Ra of the side of the transparent substrate. The surface roughness Ra of the main surface of the transparent substrate is 0.2 nm or less, and the surface roughness Ra of the chamfered surface is It advanced to 30 nm.

First, while varying the surface roughness (Ra) of the side of the transparent substrate, the heat treatment process and the ultrasonic cleaning process were sequentially performed at 100 ° C. or more, and the particle detection of the transparent substrate is summarized in Table 1 below.

On the side of the transparent substrate
Surface Roughness [Ra] Particle Detection (Transparent Board) Before heat treatment process After heat treatment process After ultrasonic cleaning Example 1 20 nm × × × Example 2 30 nm × × × Example 3 50 nm × ○ × Comparative Example 1 80 nm × ○ ○ Comparative Example 2 100 nm × ○ ○ Comparative Example 3 150 nm × ○ ○

<Table 1>

As shown in Table 1, when the surface roughness (Ra) of the side of the transparent substrate is less than 50 nm, particles are not further generated through the heat treatment process at 100 ° C. or more, but the surface roughness (Ra) of the side of the transparent substrate is 50 nm or more. In 100 ° C or more, particles were additionally detected through a heat treatment process.

In addition, when the surface roughness (Ra) of the side of the transparent substrate is 50 nm, the particles generated by the heat treatment process are completely removed by the ultrasonic cleaning process, whereas when the surface roughness (Ra) of the side of the transparent substrate is 80 nm or more, the heat treatment process Due to the particles generated by the ultrasonic cleaning process was not completely removed phenomenon occurs.

Next, a blank mask in which a metal film (light shielding film) is formed on a transparent substrate will be described. In this case, while the surface roughness (Ra) of the side of the transparent substrate is different, the heat treatment process and the ultrasonic cleaning process are sequentially performed at 100 ° C. or more, and the detection of the particles of the blank mask is summarized in Table 2 below.

On the side of the transparent substrate
Surface Roughness [Ra] Whether particles are detected (blank mask) Before heat treatment process After heat treatment process After ultrasonic cleaning Example 4 20 nm × × × Example 5 30 nm × × × Example 6 50 nm × ○ × Comparative Example 4 80 nm × ○ ○ Comparative Example 5 100 nm × ○ ○ Comparative Example 6 150 nm × ○ ○

<Table 2>

As shown in Table 2, when the surface roughness (Ra) of the side of the transparent substrate is less than 50 nm, particles are not further generated through the heat treatment process at 100 ° C. or more, but the surface roughness (Ra) of the side of the transparent substrate is 50 nm or more. In 100 ° C or more, particles were additionally detected through a heat treatment process.

In addition, when the surface roughness (Ra) of the side of the transparent substrate is 50 nm, the particles generated by the heat treatment process are completely removed by the ultrasonic cleaning process, whereas when the surface roughness (Ra) of the side of the transparent substrate is 80 nm or more, the heat treatment process Due to the particles generated by the ultrasonic cleaning process was not completely removed phenomenon occurs.

Through the results of the above Examples and Comparative Examples, the transparent substrate used for the blank mask is most preferably a surface roughness (Ra) of 30 nm or less on the side of the transparent substrate, and in the case of further performing the ultrasonic cleaning process, the transparent substrate It can be understood that the surface roughness Ra of the side surface is preferably 50 nm or less.

In addition, in the above examples and comparative examples, although the particle tendency according to the surface roughness (Ra) change of the transparent substrate chamfered surface was not examined, the transparent substrate chamfered surface also has the possibility that particles remain like the side of the transparent substrate. It is most preferable to set Ra) to 30 nm or less, and when carrying out an ultrasonic cleaning process further, it can be understood that it is desirable to set surface roughness Ra to 50 nm or less.

As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to the said Example, It is only for illustration. It is apparent to those skilled in the art from the detailed description of the present invention that various changes and modifications can be made within the spirit and scope of the present invention.

1 is a cross-sectional view of a conventional blank mask.

2 is a cross-sectional view of a blank mask according to the present invention.

Description of the Related Art

10, 20: blank mask

11, 21: transparent substrate

12, 22: thin film

13, 23: main surface

14, 24: back side

15, 25: side

16, 26: chamfer

17, 27: home

P: Particle

Claims (15)

In the transparent substrate for a blank mask having a main surface, a back side and a side, The surface roughness Ra of the side surface of the said transparent substrate is larger than 0 nm, 50 nm or less, The transparent substrate for blank masks characterized by the above-mentioned. The method of claim 1, The surface roughness Ra of the side surface of the said transparent substrate is larger than 0 nm, and is 30 nm or less transparent substrate for a blank mask. In the transparent substrate for a blank mask having a main surface, a back side and a side, The transparent substrate has a chamfered surface is formed between the main surface and the side, or between the back and side, The surface roughness Ra of the side surface and the chamfer surface of the said transparent substrate is larger than 0 nm, and is 50 nm or less transparent substrate for blank masks characterized by the above-mentioned. The method of claim 3, The surface roughness Ra of the side surface and the chamfered surface of the said transparent substrate is larger than 0 nm, and is 30 nm or less transparent substrate for a blank mask. The method according to claim 1, wherein The transparent substrate is a transparent substrate for a blank mask, characterized in that the one side is a square shape of 300mm or more. In the method for producing a transparent substrate for a blank mask having a main surface, a back surface and a side surface, Polishing a main surface, a back surface, and a side surface of the transparent substrate, The surface roughness of the side surface of the polished transparent substrate is greater than 0nm and 50nm or less, the manufacturing method of the transparent mask for a blank mask. The method of claim 6, The surface roughness Ra of the side surface of the said transparent substrate is larger than 0 nm, The manufacturing method of the transparent substrate for blank masks characterized by the above-mentioned. The method of claim 6, The method of manufacturing a transparent mask for a blank mask, characterized in that it further comprises the step of ultrasonic cleaning the transparent substrate. In the method for producing a transparent substrate for a blank mask having a main surface, a back surface and a side surface, A chamfer surface is formed between the main surface and the side surface of the transparent substrate, or between the back surface and the side surface, Grinding the main surface, the back surface, the side surface, and the chamfer surface of the transparent substrate, And a surface roughness of the polished side surfaces of the transparent substrate and the chamfered surface is greater than 0 nm and 50 nm or less. 10. The method of claim 9, The surface roughness Ra of the side surface of the said transparent substrate is larger than 0 nm, The manufacturing method of the transparent substrate for blank masks characterized by the above-mentioned. 10. The method of claim 9, The method of manufacturing a transparent mask for a blank mask, characterized in that it further comprises the step of ultrasonic cleaning the transparent substrate. A blank mask, wherein at least one thin film is formed on a transparent substrate for a blank mask according to claim 1. A method of manufacturing a blank mask in which at least one thin film is formed on a transparent substrate for a blank mask according to claim 1, Ultrasonic cleaning the transparent substrate; And forming at least one thin film on the main surface of the transparent substrate. The method of claim 13, And a step of ultrasonically cleaning the transparent substrate. The method of claim 8, A method of manufacturing a blank mask, further comprising the step of forming a resist film on the thin film.

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