KR101192470B1 - Method of manufacturing glassy carbon mold for glass molding press and method of forming a fine pattern on a glass substrate using the same - Google Patents

Abstract

The present invention provides a method for producing a glassy carbon mold for glass molding presses having a fine pattern with less surface cracks and warpage and excellent surface due to introduction of a solvent for viscosity adjustment, adjustment of conditions of a curing process, introduction of a magnetorheological fluid polishing process, and the like. . By using the glassy carbon mold for glass molding press manufactured by the above method, it is possible to easily form a glass substrate having an excellent surface fine pattern.

Description

 METHOD OF MANUFACTURING GLASSY CARBON MOLD FOR GLASS MOLDING PRESS AND METHOD OF FORMING A FINE PATTERN ON A GLASS SUBSTRATE USING THE SAME}

 The present invention relates to a method for producing a glassy carbon mold for a glass molding press and a method for forming a glass fine pattern using the same.

In the fields of display, optical communication, information storage, diagnosis and treatment, drug development, energy, etc., it is required to manufacture various types of micro- and / or nano-patterns. The main focus is on the use of plastic micro and / or nano patterns through plastic replication processes. However, plastic products are not easy to be applied to some applications due to various materials such as low heat resistance, chemical resistance, and lack of kind of optical materials, and application of glass micro and / or nanopatterns in areas where plastic materials are difficult to apply. This is required.

In the manufacturing of glass micro and / or nano-patterns, it is known that a replication process using a glass molding press process is most suitable for a mass production process among various processing methods.

However, in general, unlike the mold used in the polymer replication process, the glass molding press mold used in the glass molding press process has shape stability, hardness, and corrosion resistance under high temperature (600 ° C.) and high pressure (2.5 to 3.0 MPa) atmosphere. Maintaining is very important, and therefore, tungsten carbide (WC), aluminum nitride (AlN), titanium nitride (TiN), aluminum oxide (Al ₂ O ₃ ), and the like are used as mold materials.

The mold material is typically a difficult machining material, and a machining based on a grinding process is generally used to form a mold having a micro- and / or nano-pattern engraved shape, and the machining is performed using a minimum radius of a machining tip. (Generally, 10 μm to 100 μm) has a disadvantage that it is impossible to process the shape below. In addition, the processing cost increases exponentially according to the processing amount due to the nature of the machining, there is a limit to the formation of the array type micro and / or nano pattern. The micro pattern processing technology based on the semiconductor etching process may also be used as a micro and / or nano pattern processing process of a difficult material, but the processing cost increases due to the low etching rate.

Therefore, there is a need to develop a new concept of low cost implementation technology of micro and / or nano patterns of materials having stability under a high temperature and high pressure environment in order to provide a low cost mass production technology of glass micro and / or nano patterns.

An object of the present invention is to use a low-cost mass production technology of glass micro and / or nanopatterns having high environmental resistance and optical properties, compared to the conventional plastic micro and / or nanopatterns, to reduce fine cracks and warpage, and to provide fine patterns of excellent surfaces. There is provided a glassy carbon mold for having a glass molding press.

Another object of the present invention is to provide a method for forming a glass micropattern using a glassy carbon mold for a glass molding press which has less cracks or warpage and has an excellent surface fine pattern.

In order to achieve the above object, the step of applying a mixture comprising a thermosetting resin, a curing agent and a solvent for viscosity adjustment on a mold formed by a micro nano-processing process; Performing a first curing process on the applied mixture layer under normal temperature and vacuum atmosphere; Performing a second curing process on a thermosetting resin precursor layer on which the first curing process is performed under a temperature atmosphere of 70 ° C. to 200 ° C .; It provides a method for manufacturing a glassy carbon mold for glass molding press comprising the step of performing a carbonization process on the cured thermosetting resin precursor layer.

According to an embodiment of the present invention, the method may further include performing a magneto-Rheological polishing process on the cured thermosetting resin precursor layer between the second curing process and the carbonization process. By performing the magnetorheological fluid polishing process, the surface quality of the cured thermosetting resin precursor layer may be further improved.

According to an embodiment of the present invention, the magnetorheological fluid polishing process uses a mixture of carbonyl iron powder and water as a magnetorheological fluid, and has a magnetic field strength of 20 to 50 mT, a tool rotational speed of 200 to 500 rpm, and a specimen reciprocating speed. It can be carried out under the conditions of 0.05-1 Pa.

According to an embodiment of the present invention, the magnetorheological fluid may further include a surface cleaning process using carbon dioxide between the polishing process and the carbonization process. When the surface cleaning process is applied, residues generated by the magnetorheological fluid polishing process may be effectively removed.

Surface cleaning process using carbon dioxide gas is a clean cleaning technology that can achieve the surface cleaning by spraying dry ice particles on the surface of the cleaning object at high speed through the nozzle to remove contaminants on the surface and sublimate with them. It is a harmless and environmentally friendly cleaning process that is completely harmless to humans. It also does not damage the surface and has a fast cleaning efficiency.

In order to achieve the above another object, applying a mixture comprising a thermosetting resin, a curing agent and a solvent for viscosity adjustment on the mold formed by the micro nano-mold process; Performing a first curing process on the applied mixture layer under normal temperature and vacuum atmosphere; Performing a second curing process on the thermosetting resin precursor layer on which the first curing process is performed under a temperature atmosphere of 70 ° C. to 200 ° C .; Placing a glass substrate on the glassy carbon mold for glass molding press manufactured by the method of manufacturing a glassy carbon mold for glass molding press including performing a carbonization process on the cured thermosetting resin precursor layer; Heat-treating the glassy carbon mold and the glass substrate above the glass transition temperature of the glass substrate; Pressing the heat-treated glassy carbon mold and the glass substrate to transfer the pattern on the glassy carbon mold onto the glass substrate; Cooling the glass substrate onto which the pattern on the glassy carbon mold has been transferred; And separating the glass substrate on which the pattern on the glassy carbon mold has been transferred from the glassy carbon mold.

According to the method for producing a glassy carbon mold for glass molding press according to the present invention, the glassy carbon mold for glass molding press can be easily produced, which has little cracks or warpage and has an excellent surface fine pattern. The use of glassy carbon molds for glass molding presses enables low cost production of glass substrates with fine patterns on the surface.

1 is a cross-sectional view for explaining a method for manufacturing a glassy carbon mold for a glass molding press according to Example 1 of the present invention.
2 is a schematic of a magneto-Rheological finisher.
3 is a cross-sectional view showing a three-dimensional surface polishing process using a magnetorheological fluid.
4 is a process chart for explaining a method of forming a glass fine pattern according to Example 2 of the present invention.
5 is a graph showing the unit process mass shrinkage according to the amount of PTSA curing agent added according to Experimental Example 1 of the present invention.
6 is a graph showing the linear shrinkage rate for each unit process according to the amount of the PTSA curing agent according to Experimental Example 2 of the present invention.
FIG. 7 shows a comparison result of surface profiles of a polymer (PDMS) mold, a thermosetting resin precursor layer (furan resin precursor), and a glassy carbon (VC) mold measured using a white light interferometer.
FIG. 8 is a line width of 150 µm and a period of 300 µm that exist in the surface of the thermosetting resin layer (furan resin precursor) and the surface of the carbonized VC mold according to 0.3 part by weight and 0.6 part by weight of PTSA curing agent content, respectively, based on 100 parts by weight of the furan resin mixture. Show the micrograph of the pattern.
9 is a photograph of a furan resin cured on a PDMS mold when the first curing process is performed in a vacuum atmosphere with only 100 parts by weight of the furan resin mixture and 0.6 parts by weight of PTSA curing agent mixture according to the preliminary experiment of Experimental Example 5 of the present invention. .
10 is 100 parts by weight of a furan resin, 0.6 parts by weight of PTSA curing agent, and a molding precursor prepared only with a mixture of 100 parts by weight of furan resin and 0.6 parts by weight of PTSA curing agent under an atmospheric atmosphere, and a first curing process; Line width of 150 μm, cycle of molding precursor prepared from a mixture of 10 parts by weight of ethanol and the first curing process under vacuum atmosphere, 100 parts by weight of furan resin, 0.6 parts by weight of PTSA curing agent 10 parts by weight of ethanol mixture It is a micrograph of a 300 micrometer line pattern.
11 is a line width of 100 μm, period 200 of the surface of a furan resin precursor having a low surface quality due to fine bubbles, a surface of a furan resin precursor polished through a magnetorheological fluid polishing process, and a surface of a VC mold carbonized with a polished furan resin precursor. Micrograph of the micrometer line pattern.
12 is a line pattern photomicrograph of a line width of 30 µm and a period of 60 µm of the surface of the furan molded precursor prepared according to Experimental Example 7, the surface of the furan molded precursor after the magnetorheological fluid polishing process, and the surface of the glassy carbon (VC) mold.

Hereinafter, the present invention will be described in detail by way of examples, but the following examples are merely illustrative of the present invention, and the content of the present invention is not limited thereto.

Vitreous Carbon (VC) is a non-graphitizable carbon material which is obtained by using a thermosetting resin such as cellulose, furan resin, phenol resin, polycarbodiimide resin as a precursor. In other words, there is not enough energy to transfer to the atomic arrangement of graphite, so it does not show anisotropy even if it is heat-treated at very high temperature (3000 ℃), it is electrically, mechanically and optically isotropic and has excellent chemical resistance and excellent mechanical properties. The formation of the glassy carbon (VC) is made through a carbonization process after polymerizing and curing the thermosetting resin. The thermosetting resin exists mainly as a liquid or a solid at room temperature, and as the temperature initially increases, the viscosity of the resin decreases, thereby improving the flow of the resin, and then curing through the B-stage resin while the temperature continues to rise. At this time, the cured resin forms a three-dimensional crosslinked network structure and has insoluble properties.

After the polymerization is completed, the thermosetting resin is converted into glassy carbon (VC) through pyrolysis in the carbonization process. Since vitreous carbon (VC) has high shape stability under high temperature and high pressure, it can be applied as a mold material for glass molding press. When a predetermined pattern is formed in the thermosetting resin state and a curing and carbonization process is performed, a mold for glass molding press having a micro and / or nano pattern may be formed at a lower cost and easier than a conventional mold processing method.

However, the surface and internal bubbles of the furan resin precursor generated during the blending and curing of the high viscosity thermosetting resin not only cause deformation of the VC mold during carbonization of the resin, but also cause deterioration of surface quality and internal uniformity. Processes and / or process conditions should be introduced to improve this. In the case of glassy carbon (VC), gaseous components such as CO, CO ₂ and H ₂ O are released during the hardening and carbonization process, and heat shrinkage occurs. In this case, a carbonization process and / or process conditions for controlling the same should be introduced.

Example 1

A method of manufacturing a glassy carbon mold for a glass molding press according to an embodiment of the present invention. An embodiment of the present invention will be described as a case of forming a master pattern and forming a polymer mold on the master pattern. However, the present invention is merely illustrative and the present invention is not limited thereto. Therefore, if it is a mold formed by the micro nano mold process, it is not limited only to a polymer mold etc., It corresponds to this invention.

Referring to FIG. 1, a master pattern 100 is formed. The master substrate is prepared. Although not shown, the master substrate may include a wafer substrate, a glass substrate, a quartz substrate, and the like. The master substrate is surface treated, the photoresist is applied onto the mask substrate by spin coating, or the like, the photoresist is irradiated with ultraviolet light to expose the photoresist, and the exposed photoresist is treated with a developer. And developing to form a master pattern 100 having a predetermined pattern. If necessary, the master pattern 100 having a predetermined pattern may be a metal pattern manufactured by machining or electroplating.

The predetermined pattern may be line gratings of various line widths and periods, and rectangular and hexagonal dot patterns, chess patterns, intaglio lens patterns, intaglio lenticular lens patterns, and the like. have.

According to an embodiment of the present invention, a substrate surface treatment process of coating an adhesion promoter or hexamethyldisilazane (HMDS) on a 4-inch wafer substrate is carried out with a trialkoxy silane-based adhesion promoter. After performing the substrate surface treatment process, a photoresist such as AZ-4650 is spin coated at 4,000 rpm for about 30 seconds and soft baking is performed. A photo lithography process using a contact aligner is performed. After the developing process, hard baking may be performed on the photoresist pattern to prevent deformation of the photoresist pattern.

The polymer mold 110 is formed on the master pattern 100.

The polymer mold 110 may include a high elastic polymer such as polydimethylsiloxane (PDMS). The polymer mold 110 may be coated by a spin coating method or deposited by a chemical vapor deposition (CVD) method.

For example, a mixture of a polydimethylsiloxane (PDMS) precursor, for example, a brand name Sylgard 184 (available from Dow Corning) and a material such as dimethoxy phenyl acetophenone (DMAP) in a ratio of about 10: 1 Is deposited on the master pattern 100 and cured at about 60 ° C. for about 3 hours to form a polymer (PDMS) mold 110 on the master pattern.

In order to facilitate separation of the polymer mold 110 from the master pattern 100, an organic molecular film such as chlorotrimethylsilane may be further formed on the master pattern 100.

A mixture 120 of a thermosetting resin, a curing agent, and a viscosity adjusting solvent is applied onto the polymer mold 110. The process of mixing the thermosetting resin, the curing agent and the solvent for viscosity adjustment may be, for example, by stirring for about 30 minutes.

The thermosetting resin includes a thermosetting resin capable of forming glassy carbon in a polymerization, curing, and carbonization process such as cellulose, furan resin, phenol resin, and polycarbodiimide resin. As said furan resin, furfuryl alcohol is mentioned, for example.

The curing agent may include an acid catalyst such as p-toluenesulfonic acid monohydrate, CH ₃ C ₆ H ₄ SO ₃ H? H ₂ O, PTSA, ZnCl ₂ , citric acid, and the like. have. In another embodiment, the curing agent may include a base catalyst such as sodium hydroxide, potassium hydroxide, ammonia, amines, and the like. The curing agent may include 0.1 parts by weight to 0.6 parts by weight based on 100 parts by weight of the thermosetting resin. If it is less than 0.1 part by weight based on 100 parts by weight of the thermosetting resin, the curing rate may not be economical because it is slow, and when it exceeds 0.6 parts by weight, it may not be easy to control the curing rate.

The viscosity adjusting solvent may include solvents such as alcohols such as methanol and ethanol, ketones such as acetone, and aromatics such as toluene. If the solvent for adjusting the viscosity is not added, the viscosity of the initial mixture may be too high, thereby causing a problem that the expansion and departure of the internal bubbles are not completely performed during the curing process, and the curing may be performed in a state in which excessive bubbles are formed on the rear surface of the molding precursor. The viscosity adjusting solvent may be added to easily remove bubbles generated in the first and second curing process, especially when vacuum conditions are introduced into the curing process, if the solvent for viscosity adjustment is not added to the rear surface of the molding precursor The problem of hardening in a state of forming microbubbles may occur (see FIG. 9).

According to one embodiment of the present invention, 100 parts by weight of furan resin and 0.2 parts by weight of para-toluene sulfonic acid monohydrate (p-toluenesulfonic acid monohydrate, CH ₃ C ₆ H ₄ SO ₃ H H ₂ O, PTSA) curing agent and After stirring 10 parts by weight of the ethanol mixture for about 30 minutes, 100 parts by weight of the furan resin and 0.2 parts by weight of para-toluene sulfonic acid monohydrate (p-toluenesulfonic acid monohydrate, CH ₃ C ₆ H) were mixed on the mold 110. ₄ SO ₃ H—H ₂ O, PTSA) curing agent and 10 parts by weight ethanol mixture 120 are applied.

The thermosetting resin precursor layer 130 is prepared by performing a first curing process on the mixture layer 120 including the applied thermosetting resin, a curing agent, and a viscosity adjusting solvent. When the primary curing process is performed at room temperature and in a vacuum atmosphere, it is possible to prevent the progress of the initial curing process from being excessively large compared to the bubble escape rate in the material and to facilitate the expansion and release of the generated bubbles. Can be.

According to one embodiment of the present invention, 100 parts by weight of the applied furan resin and 0.2 parts by weight of para-toluene sulfonic acid monohydrate (p-toluenesulfonic acid monohydrate, CH ₃ C ₆ H ₄ SO ₃ H H ₂ O, PTSA The curing agent and 10 parts by weight of the ethanol mixture 130 is subjected to a primary curing process in a vacuum atmosphere for about 5 days at room temperature.

After performing the primary curing process, the final thermosetting resin precursor layer 140 in the secondary curing process to the primary cured thermosetting resin precursor layer 130 while increasing the curing temperature to a range of about 70 ℃ to 200 ℃ at a predetermined rate To form. At this time, the curing temperature is increased at a predetermined rate in order to minimize the increase in the polymerization rate due to the rapid temperature increase, thereby increasing the internal stress and blocking the gas discharge passage. For example, the secondary curing process may be heated to about 100 ℃ at a rate of about 0.1 ℃ / min, wherein the secondary curing process may be performed while maintaining the temperature for about 60 minutes every about 5 ℃ rise.

After performing the secondary curing process, the magneto-Rheological (MR) polishing process using the magneto-Rheological finisher (see FIG. 2) is performed on the secondary cured thermosetting resin precursor layer 140. To form the polished thermosetting resin precursor layer 150.

Bubbles generated in the thermosetting resin precursor layer are generated during the compounding and coating processes, and are easily discharged in the case of bubbles located inside the thermosetting resin during the curing process, whereas bubbles attached to the mold surface are generated by the high surface energy of the micro and / or nano structure. As a result, it is not easy to deviate from the surface so that it is not discharged and remains as a surface defect. Therefore, bubbles present in the thermosetting resin precursor layer are formed in most surface layers, and the thermosetting resin precursor layer having a good quality surface can be secured by peeling the surface layer while maintaining the micro and / or nanostructures.

The magnetorheological fluid polishing process means a process of removing a surface portion having a low surface quality and exposing a new surface having a high surface quality.

The magnetorheological fluid used in the magnetorheological fluid polishing process is a mixture of 85 weight% wt of carbonic iron powder and 15 weight% wt of water. Table 1 below shows an example of magnetorheological fluid polishing process conditions.

Experimental conditions Magnetorheological Fluid Polishing Permanent magnet NdFe Magnetic field strength 20mT-50mT Magnetized particles Iron carbide (average diameter 0.5 ~ 10㎛) Tool speed 200-500 rpm Specimen and Tool Clearance 10-20 mm Specimen Reciprocating Speed 0.05-1㎧ Process time 4-5 minutes

Due to the electromagnetic energy generated between the magnetized iron carbide particles when an external magnetic field is applied to the magnetorheological fluid, the iron carbide powder is aligned in the magnetic flux direction to form a chain-shaped structure. At this time, the structure has a yield stress that can be adjusted by an external magnetic field, the size of which is approximately 0 ~ 100kPa depending on the strength of the external magnetic field. In the polishing process using magnetorheological fluid, a high hardness non-magnetic or magnetizable abrasive (e.g. diamond, silicon carbide, iron-carbon nanotube composite), etc., is mixed with a magnetorheological fluid and is mixed between an electromagnet or a permanent magnet and a specimen. It is a machining method for polishing the surface of the specimen by applying a relative movement with the specimen to the fluid (see Fig. 3). At this time, the abrasive moves relative to the surface of the specimen at a certain pressure and speed. As a result, stresses above the yield stress of the fluid are concentrated on the micro-projections on the surface of the specimen, thereby removing material. The magnetorheological fluid polishing process uses a polishing tool in the form of a fluid, unlike the conventional process using a polishing tool in the form of a solid, as well as the planarization of the two-dimensional surface as well as the shape processing / polishing of the three-dimensional structure has the advantage.

That is, in the case of the general planarization process, the magnetorheological fluid polishing process maintains the shape of a predetermined pattern, in contrast to making a product having a flat surface (planarization of a two-dimensional surface) by correcting surface degradation and warpage. In this state, only the layer containing the surface defects is removed (shape processing / polishing of the three-dimensional structure), and thus, it can serve as a process for selectively removing surface defects due to the secondary curing process while maintaining a predetermined pattern. have.

In addition, by performing a magnetorheological fluid polishing process on a thermosetting resin precursor layer before performing a carbonization process other than a hard glassy carbon process formed through a curing process and a carbonization process, a glassy carbon mold having a high surface quality can be formed. .

A carbonization process is performed on the magnetorheological fluid polishing-treated thermosetting resin precursor layer 150 to form a glassy carbon (VC) mold 160. As described in the pyrolysis mechanism of the furan resin, a large amount of gas is generated in the carbonization process, so that the temperature rises up to a sufficient carbonization temperature so that the generated large amount of gas can sufficiently escape from the glassy carbon (VC) mold 160. Keep it slow. For example, it is possible to maintain about 60 minutes at every temperature rise of about 60 ° C. at a temperature increase rate of about 1 ° C./minute from room temperature to 600 ° C. in the furnace, and maintain 60 minutes after the temperature is raised to about 1000 ° C. When the carbonization process is performed, an inert gas such as nitrogen (N ₂ ) is flowed into the furnace at a rate of 500 cc / min to prevent oxidation of the glassy carbon (VC) mold 160. Can be done.

Example  2. Glass Embossing  fair

Referring to FIG. 4, the glass substrate 210 is positioned on the glassy carbon (VC) mold 200 manufactured by the manufacturing method of Example 1.

The glassy carbon (VC) mold 200 and the glass substrate 210 are heated to a glass transition temperature or higher of the glass material through heat treatment. In this case, in order to prevent oxidation of the glass material, nitrogen (N ₂ ), which is an example of an inert gas, may be flowed at a rate of 300 cc / min to 1000 cc / min.

Wherein the heat-treated glassy carbon (VC) the mold 200 and the glass in a state of contact with the substrate 210 was added to about 300㎏f / m ² to a pressure of 600㎏f / m ² wherein the vitreous carbon (VC) mold (200 ) Is transferred onto the glass substrate 210. When about 300㎏f / m ² less than the pressure, when on the glass substrate 210 may be difficult to pattern transfer, excess 600㎏f / m ² pressure, excessive to a vitreous carbon (VC) mold 200 Under pressure, certain micro and / or nano patterns may be damaged, making it difficult to obtain the desired replica micro and / or nano patterns on the glass substrate 210.

After the cooling process, the glass substrate 220 on which the pattern of the glassy carbon (VC) mold is transferred is separated from the glassy carbon mold 200 to transfer the glass substrate on which the pattern of the glassy carbon (VC) mold is transferred ( 220) is obtained. That is, fine patterns such as micro and / or nano patterns can be easily formed on the glass substrate.

Experimental Example  One. PTSA  Mass according to amount of hardener added Shrinkage  analysis

The glassy carbon (VC) mold molding properties and the mass shrinkage rate with the concentration of PTSA curing agent were analyzed. Polymers prepared according to the method of Example 1, varying the amount of PTSA curing agent by 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, and 0.6 part by weight, respectively, in 100 parts by weight of the same amount of furan resin (furipryl alcohol). ) Was applied onto the mold and the respective line weight and linear shrinkage in the pattern after the primary curing process, secondary curing process and carbonization process were analyzed.

5 shows the unit process mass shrinkage according to the amount of PTSA curing agent added according to Experimental Example 1 of the present invention. Referring to FIG. 5, in the manufacture of a VC mold, the maximum mass shrinkage occurs in a carbonization process in which pyrolysis of the furan resin occurs, and when the addition amount of the curing agent is small, relatively large mass shrinkage occurs in the primary curing process and the secondary curing process. It can be seen that the difference in mass shrinkage rate is not large in the carbonization process that occurs after the secondary curing process is completed. This is believed to be due to the volatilization characteristics of the liquid furan resin, and when the amount of the curing agent is small, the curing reaction proceeds slowly, and it is determined that the furan resin exists as a liquid having volatilization characteristics for a long time. In the secondary curing process at about 100 ° C, evaporation of the material proceeds more rapidly.When the concentration of the curing agent is high, the polymerization process is completed early and the mass change according to the concentration of the curing agent is relatively large. Judging.

Experimental Example  2. PTSA  Line according to amount of hardener added Shrinkage  Change analysis

The line shrinkage of the pattern produced according to Example 1 and Experimental Example 1 was analyzed. That is, the glass carbon (VC) mold molding characteristics and the line shrinkage rate according to the concentration of the PTSA curing agent were analyzed. The amount of the PTSA curing agent in 100 parts by weight of the furan resin was 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, and 0.6 parts by weight, respectively, and was applied on the polymer (PDMS) mold prepared according to the method of Example 1, followed by primary The line shrinkage in each pattern after curing, secondary curing, and carbonization processes was analyzed. Initial design of polymer (PDMS) mold, thermosetting resin precursor layer (furan resin precursor) complete with primary and secondary curing processes, and glassy carbon (VC) mold complete carbonization process using optical microscope for analysis of linear shrinkage The 30 μm and 70 μm linewidth patterns were measured and the averages of the measured values were compared.

FIG. 6 shows the linear shrinkage rate for each unit process according to the amount of the PTSA curing agent according to Experimental Example 2 of the present invention. Regardless of the period of the pattern, it can be seen that the unit shrinkage has similar linear shrinkage within the measurement and repeat error ranges. In particular, the linear shrinkage in the primary and secondary curing processes was about 2.3% and the linear shrinkage in the carbonization process was 20.35%. The linear shrinkage is less affected by the change in the amount of the PTSA curing agent than the mass shrinkage of the furan resin precursor because the mass loss due to volatilization during the curing process is affected by the amount of the PTSA curing agent. It did not affect the linear shrinkage, but the evaporation of the liquid furan resin, which was determined to affect the shrinkage of the entire thickness of the specimen (micro pattern).

Experimental Example  3. Surface Profile Comparison

FIG. 7 shows a comparison result of surface profiles of a master pattern, a polymer (PDMS) mold, a thermosetting resin precursor layer (furan resin precursor), and a glassy carbon (VC) mold measured using a white light interferometer. Indicates. Similar to the results measured using the microscopes of Experimental Examples 1 and 2, it was confirmed that the amount of shrinkage in the height direction was also generated about 20% during the glass mold (VC) mold manufacturing process.

Through Experimental Examples 1 to 3, it was confirmed that the mass shrinkage rate and the linear shrinkage rate in the carbonization process according to the amount of the PTSA curing agent did not have a significant influence, and there was a large difference in mass reduction due to volatilization of the material only during the curing process. This means that there may be a change in the curing rate by the amount of PTSA curing agent added and may affect the shape of the furan resin precursor. However, the addition amount of the PTSA curing agent and the manufacturing process of the furan resin precursor do not significantly affect the properties of the VC mold that proceeds after the curing is completed. Therefore, since the production conditions of the furan resin precursor do not affect the characteristics of the VC mold manufactured by the carbonization process after curing is completed, the production process of the good furan resin precursor through the carbonization process is controlled by various process conditions. It can be seen that it can be developed independently.

Experimental Example  4. PTSA  Surface bubble effect analysis according to the amount of hardener added

FIG. 8 is a line width of 150 μm and a period of 300 μm in the surface of the thermosetting resin layer (furan resin precursor) and the surface of the carbonized VC mold according to the content of 0.3 parts by weight and 0.6 parts by weight of PTSA curing agent, respectively, based on 100 parts by weight of the furan resin. Show the micrograph of the pattern. In the case of 0.3 parts by weight of PTSA curing agent content, there are defects due to bubbles on the surface, but when the addition of 0.6 parts by weight of PTSA curing agent, the surface microbubble defects appear more seriously. This was judged to have occurred because there was not enough time for the bubble of the surface to be discharged to the outside due to the increase in the curing rate according to the increase in the amount of the curing agent added. This surface bubble was confirmed to be maintained even after the carbonization process.

Experimental Example 4 confirmed that the defect of the precursor generated in the curing process of the furan resin can continue to affect even after the carbonization process. Through this, it was confirmed that the removal of microbubbles in the thermal polymerization process of the furan resin is very important and at this time, it is required to minimize the curing rate by lowering the PTSA curing agent content and to remove the microbubbles sufficiently by applying a vacuum process or the like.

Experimental Example  5. Evaluation of Microbubble Removal Process in Molding Precursor by Vacuum Process

1) Preliminary Experiment

The bubble removal of the material was attempted by carrying out the primary room temperature polymerization process in a vacuum chamber. However, referring to Figure 9, due to the high viscosity of the mixture of the lower temperature Furan resin and the PTSA curing agent under the vacuum process, the expansion and departure of the internal bubbles during the vacuum process is not achieved completely and excessive microbubble on the back of the molding precursor The problem which hardened in the formed state generate | occur | produced. Therefore, when forming a molding precursor using only the furan resin and the PTSA curing agent through the preliminary experiment, it may be disadvantageous in terms of the formation of micro-bubbles, a process that can reduce the amount of micro-bubbles, or remove the generated micro-bubbles I could confirm the need.

2) Evaluation of microbubble removal process in precursor through vacuum process

In order to solve the problem of excessively forming microbubbles, a solvent for adjusting viscosity was mixed in the process of mixing a mixture of a thermosetting resin (eg, furan resin) and a curing agent (eg, PTSA curing agent). The viscosity adjusting solvent may include solvents such as alcohols such as methanol and ethanol, ketones such as acetone, and aromatics such as toluene. In the experimental example of the present invention, as the solvent for viscosity adjustment, the surface of the furan precursor according to the addition of ethanol solvent and / or vacuum atmosphere was compared.

A mixture of the furan resin and 0.6 parts by weight of the PTSA curing agent was subjected to a primary curing process, a secondary curing refining process and a carbonization process under atmospheric pressure (atmosphere), and 100 parts by weight of the furan resin and 0.6 parts by weight of the PTSA curing agent were mixed. About 10 parts by weight of ethanol was added to the process to lower the viscosity of the mixture of the initial furan resin and 0.6 parts by weight of the PTSA curing agent, and the first curing process, the second curing refining process, and the carbonization process were performed in an air atmosphere or a vacuum atmosphere.

The mass change rate of 100 parts by weight of the furan resin and 0.6 parts by weight of the PTSA curing agent mixture added with about 10 parts by weight of ethanol was 100 parts by weight of the furan resin and 0.6 parts by weight of the PTSA curing agent mixture (atmosphere) during the primary curing process by evaporation of ethanol. Compared to the mass shrinkage, the mass shrinkage rate and the linear shrinkage rate in the secondary curing process and the carbonization process were not significantly different according to the addition of ethanol.

10 is 100 parts by weight of a furan resin, 0.6 parts by weight of PTSA curing agent, and a molding precursor prepared only with a mixture of 100 parts by weight of furan resin and 0.6 parts by weight of PTSA curing agent under an atmospheric atmosphere, and a first curing process; Line width 150 μm of the surface of the molded precursor prepared from a mixture of 10 parts by weight of ethanol and a molded precursor prepared from a mixture of 10 parts by weight of ethanol under vacuum atmosphere and 100 parts by weight of furan resin, 0.6 parts by weight of a PTSA curing agent 10 parts by weight of an ethanol mixture. Μm line pattern micrograph.

Through Experimental Example 5, it was confirmed that a considerable amount of surface bubbles can be removed through the addition of ethanol, which is a viscosity adjusting solvent, and a vacuum atmosphere curing process.

Experimental Example  6. Magnetorheological fluid ( Magneto - Rheological ; MR ) Precursor surface through polishing process and VC Mold  Improved surface properties

Bubbles formed in the furan resin molding precursor formed according to the method of Example 1 remained mainly at the interface with the PDMS in the polymerization process, and the internal bubbles except the interface were substantially removed in the polymerization process. In this experimental example, as shown in FIG. 3, a magneto-Rheological (MR) polishing process using a magneto-Rheological finisher is performed to remove a surface portion having a low surface quality and a new surface having a high surface quality. The process of exposing was performed.

The magnetorheological fluid used in the magnetorheological fluid polishing process is a mixture of 85 weight% wt of carbonic iron powder and 15 weight% wt of water. Table 1 shows the magnetorheological fluid polishing process conditions of the present experimental example.

FIG. 11 is a line pattern and a lattice pattern micrograph of a pattern width of 100 μm cycle 200 μm of a surface of a VC mold obtained by grinding a furan resin precursor surface having a low surface quality by microbubbles through a magnetorheological fluid polishing process.

Through Experimental Example 6, by performing a magnetorheological fluid polishing process, it is possible to form a furan resin precursor having excellent surface quality, and by performing a carbonization process on the thermosetting resin layer, glassy carbon having excellent surface quality (VC). It was confirmed that the mold can be prepared.

In the magnetorheological fluid polishing process, the magnetorheological fluid particles attached to the surface and the particles separated from the furan resin precursor may be improved through a surface cleaning process using carbon dioxide gas. Surface cleaning process using carbon dioxide gas can achieve the surface cleaning by spraying dry ice particles to the surface of the cleaning object through a nozzle at high speed to remove contaminants on the surface and sublimate with them.

Experimental Example  7. Glassy Carbon ( VC ) Of mold  Surface properties

According to the process analysis and the process variable influence analysis through the manufacturing process according to Example 1 and a series of experimental examples, the first curing process of a mixture of 100 parts by weight of furan resin, 0.1 parts by weight PTSA curing agent, 10 parts by weight ethanol under vacuum atmosphere After performing the secondary curing process, the magnetorheological fluid polishing process was performed to perform a surface polishing and a carbonization process to prepare a glassy carbon (VC) mold. By maintaining a small amount of the PTSA curing agent and performing a curing process under vacuum conditions, it was possible to significantly reduce bubbles generated on the surface and to further improve the surface quality after the magnetorheological fluid polishing process. 12 is a surface micrograph of the surface of the furan molded precursor prepared according to Experimental Example 7, the surface of the furan formed precursor after the magnetorheological fluid polishing process and the glassy carbon (VC) mold.

According to an embodiment of the present invention, by applying a solvent for viscosity adjustment, keeping the amount of PTSA hardener added and performing the primary curing process under vacuum conditions, bubbles generated on the surface can be significantly reduced, magnetorheological fluid polishing process It was confirmed that by applying the surface quality of the glassy carbon mold for glass molding press can be further improved. In addition, when using the glassy carbon (VC) mold for glass molding press with improved surface quality, the durability of the glassy carbon (VC) for glass molding press is not only continuously available for the micropattern forming process but also with high precision micropattern. Can be easily formed. In addition, after the magnetorheological fluid polishing process, the particles in the magnetorheological fluid and the polished furan resin precursor particles are adhered to the surface and appear as defects of the VC mold after the carbonization process, which can be improved by a carbon dioxide gas washing process.

Claims (5)

Applying a mixture including a thermosetting resin, a curing agent and a solvent for viscosity adjustment on the mold formed by the micro nano-processing process;
Performing a first curing process on the applied mixture layer under normal temperature and vacuum atmosphere;
Performing a second curing process on a thermosetting resin precursor layer on which the first curing process is performed under a temperature atmosphere of 70 ° C. to 200 ° C .;
A method of manufacturing a glassy carbon mold for glass molding press comprising the step of performing a carbonization process on the cured thermosetting resin precursor layer. The glassy carbon mold of claim 1, further comprising performing a magneto-rhetic polishing process on the cured thermosetting resin precursor layer between the second curing process and the carbonization process. How to make. According to claim 2, The magnetorheological fluid polishing process using a mixture of carbonic iron powder and water as a magnetorheological fluid, magnetic field strength of 20 to 50mT, tool rotational speed of 200 to 500rpm, specimen reciprocating speed of 0.05 to 1 Process for producing a glassy carbon mold for glass molding press, characterized in that carried out under the conditions of. The method of manufacturing a glassy carbon mold according to any one of claims 2 to 3, further comprising a surface cleaning step using carbon dioxide between the magnetorheological fluid polishing step and the carbonization step. Placing a glassy carbon mold for the glass molding press produced by the method of claim 1 on a glass substrate;
Heat-treating the glassy carbon mold and the glass substrate above the glass transition temperature of the glass substrate;
Pressing the heat-treated glassy carbon mold and the glass substrate to transfer the pattern on the glassy carbon mold onto the glass substrate;
Cooling the glass substrate onto which the pattern on the glassy carbon mold has been transferred; And
Separating the glass substrate on which the pattern on the glassy carbon mold has been transferred from the glassy carbon mold.

Images