KR102599186B1 - Faraday box and method for plasma etching process using thereof - Google Patents

Abstract

The present invention relates to a Faraday box and a plasma etching method using the same. Specifically, it relates to a Faraday box capable of forming a light guide plate with a specific grid pattern and depth gradient using a plasma etching method using a Faraday box including an extension, and a plasma etching method using the same.

Description

Faraday box and plasma etching method using the same {FARADAY BOX AND METHOD FOR PLASMA ETCHING PROCESS USING THEREOF}

The present invention relates to a Faraday box and a plasma etching method using the same. Specifically, it relates to a Faraday box capable of forming a light guide plate with a specific grid pattern and depth gradient using a plasma etching method using a Faraday box including an extension, and a plasma etching method using the same.

Recently, as interest in display units that implement augmented reality (AR), mixed reality (MR), or virtual reality (VR) has grown, research on display units that implement them has been actively conducted. There is a trend. A display unit implementing augmented reality, mixed reality, or virtual reality includes a diffraction grating light guide plate that uses a diffraction phenomenon based on the wave properties of light. The diffraction grating light guide plate includes a diffraction grating pattern that can guide the light incident on the diffraction grating light guide plate to one point by internally reflecting or total internally reflecting the incident light.

Various methods are used to manufacture the diffraction grating light guide plate as described above, and the diffraction grating light guide plate is generally manufactured through an imprinting method using a mold. At this time, plasma etching is performed on the etching substrate to form a diffraction grating pattern, thereby manufacturing a mold for a diffraction grating light guide plate.

However, when using plasma etching using a conventional Faraday box having a cylindrical shape, there was a problem in that the etching speed decreased sharply as the distance between the etched part and the mesh part increased. As a result, the etching process time increased and the etching process was reduced. There was a problem in that the process temperature at the top of the substrate rapidly increased due to the influence of ion collisions.

Furthermore, when plasma etching is performed by providing an etching substrate on a support having an inclined surface, there is a problem in that the upper part of the etching substrate is not cooled smoothly during the process because it is far away from the cooling portion formed on the bottom.

In addition, when plasma etching is performed using a conventional Faraday box having a cylindrical shape and providing an etching substrate on a support having an inclined surface, a grid pattern with the inclined direction facing outward from the etching substrate can be formed. However, there was a problem in that it was difficult to form a grid pattern in which the inclined direction was directed toward the inside of the etching substrate.

Accordingly, there is a need for technology that can precisely form a pattern part with a specific grid pattern and depth gradient through a plasma etching process using a Faraday box including an expansion part.

The present invention seeks to provide a Faraday box capable of forming a light guide plate with a specific grid pattern and depth gradient using a plasma etching method using a Faraday box including an extension, and a plasma etching method using the same.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

One embodiment of the present invention seeks to provide a Faraday box including a bottom surface, an inclined portion disposed at an angle to the bottom surface and having a mesh portion formed thereon, and an extension portion of the bottom surface extending outward from a lower end of the inclined portion.

Another embodiment of the present invention includes providing a substrate for etching on the bottom of the Faraday box; and forming a first pattern portion by performing plasma etching on the etching substrate to form a first pattern portion, wherein the step of providing the etching substrate includes placing a portion of the etching substrate on the expanded portion. We would like to provide a plasma etching method using a Faraday box.

The Faraday box according to an exemplary embodiment of the present invention includes an expansion portion extending outside the lower end of the inclined portion, thereby providing the effect of forming a specific grid pattern by providing a portion of the etching substrate to the expansion portion.

The plasma etching method using a Faraday box according to an embodiment of the present invention can form a pattern portion having a grid pattern inclined inward of the etching substrate by providing a part of the etching substrate to the expanded portion, and the mesh portion. By arranging a shutter portion of a specific length on the image, the depth gradient can be precisely adjusted.

The effect of the present invention is not limited to the above-mentioned effect, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the attached drawings.

Figure 1 is a diagram showing a cylindrical Faraday box according to the prior art.
Figure 2 is a schematic diagram schematically showing a plasma etching method using a cylindrical Faraday box according to the prior art.
Figure 3 is a graph showing the results of measuring the etch rate according to the distance from the mesh portion of the Faraday box.
Figure 4 is a photograph, side view, and front view of a Faraday box according to an exemplary embodiment of the present invention.
Figure 5 is a diagram showing the depth gradient according to the position and etching time of the etched substrate after plasma etching using the Faraday box of the present invention.
Figure 6 is a diagram showing a grid pattern manufactured by a plasma etching method using a cylindrical Faraday box according to the prior art, forming a pattern inclined to the outside of the etching substrate.
Figure 7 is a diagram of a grid pattern manufactured by a plasma etching method using a cylindrical Faraday box according to the prior art, forming a pattern inclined inward on a substrate for etching.
Figure 8 is a diagram of a grid pattern produced by a plasma etching method using a Faraday box of the present invention, forming a pattern inclined to the outside of the etching substrate.
Figure 9 is a diagram of a grid pattern produced by a plasma etching method using a Faraday box of the present invention, forming a pattern inclined inward on a substrate for etching.
Figure 10 is an image of a substrate for etching etched using a plasma etching method using a Faraday box of the present invention, and an image observed with a scanning electron microscope (SEM) that confirms that the depth varies depending on the etching time.
Figure 11 is a schematic diagram showing a Faraday box including a shutter according to an embodiment of the present invention.
Figure 12 is a photograph showing a Faraday box including a shutter according to an exemplary embodiment of the present invention.
Figure 13 is a graph showing plasma etching using a Faraday box in which the mesh portion is shielded with a shutter having a length of 30 mm according to an embodiment of the present invention, and showing a depth gradient according to the position of the etching substrate.
Figure 14 shows plasma etching using a Faraday box whose mesh portion is shielded with shutters having lengths of 30 mm, 35 mm, and 40 mm according to an embodiment of the present invention, and showing a depth gradient according to the position of each etching substrate. It is also a graph.
Figure 15 shows plasma etching using a Faraday box whose mesh portion is shielded with shutters having lengths of 30 mm, 35 mm, and 40 mm according to an embodiment of the present invention, and depth gradients are confirmed according to the positions of each etching substrate. This is an image observed using a scanning electron microscope (SEM).

Throughout the specification of the present application, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Throughout this specification, when a member is said to be located “on” another member, this includes not only the case where the member is in contact with the other member, but also the case where another member exists between the two members.

Throughout this specification, the terms “step of” or “step of” as used herein do not mean “step for.”

In the present invention, a Faraday box refers to a closed space made of a conductor. When the Faraday box is installed in a plasma, a sheath is formed on the outer surface of the box to maintain a constant electric field inside. At this time, when the upper surface of the Faraday box is formed with a mesh portion, a sheath is formed along the surface of the mesh portion. Therefore, when performing plasma etching using a Faraday box, ions accelerated in a direction perpendicular to the sheath formed horizontally on the surface of the mesh unit enter the inside of the Faraday box and then maintain the direction at the time of incident. As it reaches this point, the substrate is etched. Furthermore, in the present invention, the mold base surface inside the Faraday box can be fixed in a horizontal or inclined state with respect to the mesh surface, and ions are incident in a direction perpendicular to the mesh surface, so the mold base surface is perpendicular or inclined. Etching in an inclined direction is possible. The Faraday box may be a conductive box whose upper surface consists of a conductive mesh portion. The etching direction of the plasma etching may be perpendicular or inclined to the surface of the mesh portion of the Faraday box.

In the case of plasma etching using a Faraday box, ions that pass through the mesh portion collide with neutral particles present inside the Faraday box while moving toward the substrate and lose kinetic energy. As a result, the ion density increases with the mesh. It tends to be inversely proportional to wealth distance. That is, the closer the ions are to the mesh part, the higher the etch rate is, and the farther away the ions are from the mesh part, the lower the etch rate.

The present inventors studied a plasma etching method using a Faraday box having the above-described characteristics, and specifically studied a Faraday box and plasma etching method that can implement grid patterns and depth gradients that cannot be implemented in the Faraday box, The following invention was developed.

Hereinafter, the present invention will be described in more detail.

Figure 1 is a diagram showing a cylindrical Faraday box 1 according to the prior art. When using the cylindrical Faraday box, the etching substrate 7 was placed on the support 9 having an inclined surface and plasma etching was performed to form an inclined grid pattern. However, when using a cylindrical Faraday box of the prior art as shown in FIG. 1, it was easy to form the grid pattern of the etching substrate on the outside of the etching substrate, but the grid pattern of the etching substrate was formed on the inside of the etching substrate. There was a problem that it was not easy to form.

Figure 2 is a schematic diagram schematically showing a plasma etching method using a cylindrical Faraday box according to the prior art. Figure 2(a) shows a method of manufacturing the grid pattern so that it faces outward from the etching substrate. That is, in order to manufacture a grid pattern facing the outside of the etching substrate, the etching substrate 7 is provided on a support 9 having an inclined surface and plasma etching is performed so that etching is performed on the upper part of the support having an inclined surface. do. Accordingly, a grid pattern facing outward from the etching substrate is effectively formed. However, in order to form a grid pattern with the grid pattern facing outward from the etching substrate, the lower portion of the etching substrate 7 must be etched as shown in FIG. 2(b). However, there was a problem in that the etching speed by plasma rapidly decreased as the distance between the mesh portion 3 and the etching substrate 7 increased.

Specifically, a support having an inclined surface of 40° was installed in a Faraday box, a substrate for etching was provided on the support, and then plasma etching was performed using ICP-RIE (Oxford plasmaLab system100). At this time, as reactive gases, O2 and C ₄ F ₈ were mixed at a ratio of 1:9 and supplied at a flow rate of 50 sccm. Additionally, the etching conditions were RF power of 150 W, ICP power of 2 kW, and operating pressure of 7 to 10 mTorr for 3 minutes. Through this, the etch rate was measured according to the distance from the mesh part of the Faraday box, and the results are shown in Figure 3.

Figure 3 is a graph showing the results of measuring the etch rate according to the distance from the mesh portion of the Faraday box. As shown in FIG. 3, it can be seen that the etching speed decreases rapidly as the distance between the mesh portion and the etching substrate increases.

In order to solve this problem, there is a method of forming a grid pattern on the upper surface of the support 9 having an inclined surface, but as shown in FIG. 2(c), the etching substrate 7 is structurally damaged due to the mesh portion 3. There was a problem in that it could not be provided on the upper part of the support.

Figure 4 is a photograph, side view, and front view of a Faraday box according to an exemplary embodiment of the present invention. According to an exemplary embodiment of the present invention to solve the above-described problem, there is a bottom surface 11, an inclined portion 13 formed with a mesh portion 15 disposed at an angle to the floor surface, and the bottom surface is a lower end of the inclined portion. A Faraday box is provided having an expansion portion 17 extending outward. By including the extension portion 17, the Faraday box has the effect of controlling the etching position of the etching substrate 19 and forming a grid pattern in a specific direction. In addition, when placing a relatively large etching substrate in a cylindrical Faraday box, there are structural limitations in controlling the position where etching occurs. However, the present invention includes an extension portion 17 as shown in FIG. 4, Even if the etching substrate is large in size, there is an effect in that plasma etching can be performed where a grid pattern is desired to be formed by placing the etching substrate on the expanded portion.

According to an exemplary embodiment of the present invention, the inclination angle formed between the bottom surface and the slope may be 30° or more and 70° or less. Specifically, the inclination angle may be 35° or more and 65° or less, 40° or more and 60° or less, or 45° or more and 55° or less. By adjusting the inclination angle formed by the bottom surface and the inclined portion within the above-mentioned range, the inclination angle of the grid pattern of the etching substrate can be adjusted.

According to one embodiment of the present invention, the Faraday box may further include a shutter 21 on the mesh portion. By including a shutter on the mesh portion of the Faraday box, it is possible to precisely control the depth of the grid pattern and fine depth gradients.

Figure 5 is a diagram showing the depth gradient according to the position and etching time of the etched substrate after etching using the Faraday box of the present invention. In order to check the etching depth according to the etching time and the position of the etching substrate using the Faraday box of the present invention, the outer size of the inclined surface is 100mm Plasma etching was performed using a Faraday box with a surface inclination angle of 40°. Before plasma etching, the pitch (one cycle of the grid pattern) is 405 nm and the line duty (ratio of the length of Al in the grid pattern) is 50% on the etching substrate of size 110 mm x 90 mm made of quartz. After forming the Al line grid, it was placed on the bottom of the Faraday box of the present invention and plasma etching was performed. Afterwards, in order to check the depth gradient, the depth of the cross section was checked at 3 mm intervals in the center of the etching substrate, and a graph as shown in FIG. 5 was created. As shown in FIG. 5, when plasma etching is performed for 2 minutes and 5 minutes, the tendency of etch depth is maintained according to different etching speeds for each location as shown in FIG. 5(b), but the time for etching to proceed by plasma increases. You can see that the vertical depth increases as you do this. However, as shown in FIG. 5(b), there are two places where the etching efficiency is significantly high. In order to improve the etching efficiency, the etching substrate can be selectively provided at places close to and far from the mesh portion. You can.

Figure 6 is a diagram showing a grid pattern manufactured by a plasma etching method using a cylindrical Faraday box according to the prior art, forming a pattern inclined to the outside of the etching substrate. As shown in FIG. 6(a), according to the prior art, a substrate for etching is placed on a support having an inclined surface within a cylindrical Faraday box, and the upper portion of the substrate for etching is selectively etched with plasma. Afterwards, plasma etching was performed by placing the unetched half on the upper part of the support having the inclined surface. As a result, a grid pattern slanted toward the outside of the etching substrate was formed, as shown in FIG. 6(b). In addition, as shown in FIG. 6(c), the upper part of the support having an inclined surface, that is, the part close to the mesh part, has a fast etching speed because the plasma ions are immediately incident on the Faraday box, and the quality of the grid pattern formed by the plasma etching is poor. You can confirm that it is good.

Figure 7 is a diagram of a grid pattern manufactured by a plasma etching method using a cylindrical Faraday box according to the prior art, forming a pattern inclined inward on a substrate for etching. In order to form an inwardly inclined grid pattern of the etching substrate, the lower part of the etching substrate located on the lower surface of the support having an inclined surface as shown in FIG. 7(a) must be plasma etched to form a grid pattern as shown in FIG. 7(b). do. However, as shown in FIG. 3, as the distance between the mesh portion and the etching substrate increases, the etching speed decreases significantly, and the etching quality deteriorates due to external influences. Therefore, when plasma etching is performed as shown in FIG. 7(a), the process time takes a long time due to a decrease in the etching speed, and there is a problem in that the etching quality deteriorates as shown in FIG. 7(c).

According to another embodiment of the present invention to solve the above-described problem, providing a substrate for etching on the bottom of the Faraday box; and forming a first pattern portion by performing plasma etching on the etching substrate to form a first pattern portion, wherein the step of providing the etching substrate includes placing a portion of the etching substrate on the expanded portion. Provides a plasma etching method using a Faraday box.

According to one embodiment of the present invention, after the step of forming the first pattern portion, the etching substrate is provided on the bottom surface so that the portion where the first pattern portion of the etching substrate is formed is located in the expansion portion, and the etching substrate is provided on the bottom surface. The second pattern portion forming step may be performed by performing plasma etching on the substrate to form the second pattern portion.

Figure 8 is a diagram of a grid pattern produced by a plasma etching method using a Faraday box of the present invention, forming a pattern inclined to the outside of the etching substrate. As shown in FIG. 8(a), after placing the etching substrate on the bottom surface, a portion of the etching substrate is selectively plasma etched to form a first pattern portion, and then the unetched portion of the etching substrate is selectively plasma etched. By etching to form the second pattern portion, it is possible to form a grid pattern inclined outward of the etching substrate as shown in FIG. 8(b).

Figure 9 is a diagram of a grid pattern produced by a plasma etching method using a Faraday box of the present invention, forming a pattern inclined inward on a substrate for etching. As shown in FIG. 9(a), a first pattern portion is formed by placing a part of the etching substrate in the expansion portion and etching the etching substrate. Then, the etched portion of the etching substrate is placed in the expansion portion and etched. By plasma etching the remaining half of the etching substrate to form a second pattern portion, a grid pattern inclined inward of the etching substrate can be formed as shown in FIG. 9(b).

Figure 10 is an image of a substrate for etching etched using a plasma etching method using a Faraday box of the present invention, and an image observed with a scanning electron microscope (SEM) to confirm that the depth is different over etching time. By performing plasma etching using the Faraday box of the present invention, it can be confirmed that the depth of the grid pattern decreases with etching time.

According to one embodiment of the present invention, the plasma etching may be performed after shielding at least a portion of the mesh portion with a shutter. According to one embodiment of the present invention, the shutter may continuously shield a certain area of the mesh part. As described above, by shielding the mesh portion with a shutter, the depth gradient can be precisely adjusted.

According to one embodiment of the present invention, the shutter may shield 20% to 80% of the mesh portion. Specifically, the shutter may shield 30% to 60% of the mesh portion, or 40% to 60% of the mesh portion. Specifically, the shutter may shield 50% of the mesh portion.

According to one embodiment of the present invention, the shutter may be made of aluminum oxide. However, the material of the shutter is not limited to this, and shutters of various materials may be used.

Figure 11 is a schematic diagram showing a Faraday box including a shutter according to an embodiment of the present invention. As shown in FIGS. 11(a) and 11(b), the shutter can be placed on the mesh part, and the shutter can be placed at the lower end of the mesh part. Additionally, by placing a shutter on the upper part of the mesh portion, the position at which the etching substrate is plasma etched can be adjusted. Figure 11(c) shows an embodiment of shielding the mesh portion by positioning the shutter at an inclined portion. The method of shielding the mesh portion is not limited to this, and the mesh portion can be shielded in various ways.

Figure 12 is a photograph showing a Faraday box including a shutter according to an exemplary embodiment of the present invention. As shown in 12 above, a portion of the mesh portion can be shielded by placing it on an inclined portion. Additionally, by shielding a portion of the mesh portion, the depth gradient of the grid pattern of the etching substrate can be precisely controlled.

According to an exemplary embodiment of the present invention, the etching substrate may be provided parallel to the bottom surface. By providing the etching substrate in parallel with the bottom surface, the grid pattern can be precisely controlled.

According to one embodiment of the present invention, the substrate for etching may be a quartz substrate or a silicon wafer. When using the plasma etching method using the Faraday box, the occurrence of needle-like structures that can occur when forming a lattice pattern on a glass or silicon wafer such as a quartz substrate as an etching substrate can be greatly reduced, and the etching speed can be improved to improve process time. can be shortened.

According to one embodiment of the present invention, the mesh portion may have a sheet resistance of 0.5 Ω/□ or more. Specifically, according to an exemplary embodiment of the present invention, the sheet resistance of the mesh portion may be 0.5 Ω/□ or more and 100 Ω/□ or less.

If the sheet resistance of the mesh part is 0.5 Ω/□ or more, the etching speed for each position within the Faraday box can be kept constant during plasma etching. Additionally, when the sheet resistance of the mesh portion is less than 0.5 Ω/□, the etching speed for each position of the Faraday box is formed irregularly during plasma etching, making it difficult to perform precise etching. Furthermore, if the sheet resistance of the mesh part is 0.5 Ω/□ or more, the etching speed for each position within the Faraday box can be kept constant, and if the sheet resistance exceeds 100 Ω/□, the increase in effect is minimal and the manufacturing cost increases. It can only happen.

According to an exemplary embodiment of the present invention, the mesh part may have fluorocarbon radicals adsorbed on a metal mesh. Specifically, the fluorocarbon radical may be -CF, -CF ₂ , -CF ₃ or -C ₂ F _x (x = integer from 1 to 5). Specifically, during plasma etching of the mesh portion of the Faraday box, fluoride radicals may be adsorbed to the mesh portion due to etching and surface polymerization by F radicals.

According to an exemplary embodiment of the present invention, the mesh part can exhibit sheet resistance as described above by adsorbing the fluorocarbon radicals on a conductive material such as metal.

According to one embodiment of the present invention, the mesh part may use a mesh made of stainless steel. Specifically, #200 (pitch 125 ㎛, wire diameter 50 ㎛, opening ratio 36%) commercial mesh made of SUS304 can be used. However, it is not limited to this, and the mesh portion may be made of Al, Cu, W, Ni, Fe, Mo, and an alloy containing at least two types of these. Furthermore, the porosity and lattice size of the mesh can be freely adjusted depending on the purpose of etching.

According to one embodiment of the present invention, the plasma etching may use inductively coupled plasma reactive ion etching equipment (ICP-RIE). Specifically, the step of forming the pattern portion may be performed by providing the Faraday box inside an inductively coupled plasma reactive ion etching equipment. In addition, the plasma etching can be applied to a helicon plasma method, a helical resonance plasma method, and an electron resonance plasma method.

According to one embodiment of the present invention, the plasma etching may include adjusting the output of the plasma etching device to 0.75 kW or more and 4 kW or less. Specifically, the output of the plasma etching device may be adjusted from 0.75 kW to 3 kW, from 0.75 kW to 1.5 kW, or from 0.75 kW to 1 kW.

According to an exemplary embodiment of the present invention, the plasma etching may include supplying a mixed gas containing a reactive gas and oxygen gas to the plasma etching device at a rate of 10 sccm or more and 75 sccm or less. Specifically, the plasma etching is performed by applying the mixed gas to the plasma etching device at a rate of 15 sccm to 75 sccm, 25 sccm to 70 sccm, 30 sccm to 70 sccm, 40 sccm to 60 sccm, or 45 sccm to 55 sccm. It may include supply below.

When the supply flow rate of the reactive gas is adjusted to the above range, the formation of needle-like structures that occur when patterning an etching substrate, specifically a quartz substrate or silicon wafer, is further suppressed, and the size of the needle-like structures that occur is significantly reduced. It can be suppressed. Furthermore, the depth gradient of the grid pattern of the etching substrate can be precisely controlled.

According to an exemplary embodiment of the present invention, the reactive gas may be a general reactive gas used in plasma etching. For example, gases such as SF ₆ , CHF ₃ , C ₃ F ₈ , CF ₄ , and Cl ₂ can be used.

According to an exemplary embodiment of the present invention, the content of oxygen gas flow rate in the total flow rate of the mixed gas may be 1% or more and 20% or less. Specifically, the content of the oxygen gas flow rate in the total flow rate of the mixed gas may be 1% or more and 15% or less, 1% or more and 10% or less, or 1% or more and 5% or less.

When the content of the oxygen flow rate in the mixed gas flow rate is within the above range, the formation of needle-like structures that may occur when forming a pattern portion on an etching substrate, specifically a quartz substrate or silicon wafer, is further suppressed, and the formation of needle-like structures that occur is further suppressed. The size can be significantly reduced. Furthermore, the depth gradient of the grid pattern of the etching substrate can be precisely controlled.

According to one embodiment of the present invention, a metal mask may be provided on the etching substrate. By providing a metal mask on the etching substrate, a grid pattern of the etching substrate can be precisely formed.

According to one embodiment of the present invention, the bottom surface of the Faraday box may include a metal having a lower ionization tendency than the metal mask.

According to one embodiment of the present invention, the bottom surface of the Faraday box may include a metal that is 1 V or more higher than the standard reduction potential of the metal mask. Specifically, the bottom surface of the Faraday box may be made of metal that has a standard reduction potential of 1 V or more higher than the standard reduction potential of the metal mask. Additionally, the average standard reduction potential of the metal constituting the bottom surface of the Faraday box may be 1 V or more higher than the standard reduction potential of the metal mask. The average standard reduction potential of the metal constituting the bottom surface of the Faraday box can be calculated by considering the standard reduction potential and the content of the metal constituting the bottom surface of the Faraday box. For example, in the case of SUS304 consisting of 18 wt% Cr, 8 wt% Ni, and 74 wt% Fe, the average standard reduction potential may be -0.333 V. For reference, the standard reduction potential of Cr is -0.74 V, the standard reduction potential of Fe is -0.45 V, the standard reduction potential of Ni is -0.26 V, the standard reduction potential of Al is -1.66 V, and the standard reduction potential of Cu is 0.34. It's V.

According to one embodiment of the present invention, the bottom surface of the Faraday box may include metal that is 1 V or more, 1.5 V or more, or 1.9 V or more higher than the standard reduction potential of the metal mask. In addition, according to one embodiment of the present invention, the average standard reduction potential of the metal constituting the bottom surface of the Faraday box is higher than the standard reduction potential of the metal mask by 1 V or more, 1.5 V or more, or 1.9 V or more. You can.

When the standard reduction potential of the metal included in the bottom of the Faraday box is as described above, when forming a pattern portion on an etching substrate, specifically a quartz substrate or silicon wafer, the occurrence of needle-like structures is minimized, and further, the needles generated are minimized. The size of the structure can be minimized. Additionally, the plasma etching can precisely control the depth gradient of the etching substrate.

According to one embodiment of the present invention, the metal mask may include at least one of aluminum and chromium, and the bottom surface of the Faraday box may include copper.

According to one embodiment of the present invention, the metal mask includes at least one of aluminum and chromium. Specifically, the metal mask may be made of aluminum.

According to one embodiment of the present invention, the bottom surface of the Faraday box may contain at least one of iron, nickel, and copper. Specifically, the bottom of the Faraday box may be a metal plate made of copper or stainless steel, which is an alloy of iron, chromium, and nickel.

According to one embodiment of the present invention, the metal mask is a mask made of aluminum, and the bottom surface of the Faraday box may be a metal plate made of copper or SUS304 stainless steel.

According to one embodiment of the present invention, the metal mask may include at least one of aluminum and chromium, and the bottom surface of the Faraday box may include copper. Specifically, the metal mask may be made of aluminum with a purity of 95% or higher, and the bottom of the Faraday box may be a copper plate with a purity of 95% or higher.

As in the present invention, when the ionization tendency of the bottom material of the Faraday box is lower than the ionization tendency of the metal mask material, and/or the standard reduction potential of the bottom material of the Faraday box is 1 lower than the standard reduction potential of the metal mask material. When V is higher than that, the generation of needle-like structures during patterning of an etching substrate, specifically a quartz substrate or silicon wafer, is significantly suppressed, and the size of the needle-like structures generated can be suppressed to a significantly smaller size.

According to one embodiment of the present invention, the etching substrate on which the pattern is formed may be a mold substrate for a diffraction grating light guide plate.

According to an exemplary embodiment of the present invention, the step of forming the pattern portion may include performing plasma etching with the etching substrate provided to be accommodated in an expansion portion.

An exemplary embodiment of the present invention includes preparing a substrate on which a diffraction grating pattern is formed using a plasma etching method using the Faraday box; Applying a resin composition onto a quartz substrate on which the diffraction grating pattern is formed; Providing a transparent substrate on a surface opposite to the surface provided with the diffraction grating pattern; curing the resin composition to form a diffraction grating pattern; and separating the quartz substrate and the diffraction pattern to form a diffraction grating light guide plate.

The resin composition can be used without limitation as long as it is a resin composition commonly used in the industry. Furthermore, the step of applying the resin composition may be performed using coating methods commonly used in the art, such as spin coating, dip coating, and drop casting.

The method of manufacturing the diffraction grating light guide plate may be a general method of forming a patterned layer, except that a quartz substrate patterned by the plasma etching method using the Faraday box described above is used.

The diffraction grating light guide plate can be directly used as a diffraction grating light guide plate. Additionally, the final product can be manufactured by using the diffraction grating light guide plate as an intermediate mold and replicating it. Specifically, when manufacturing a diffraction grating light guide plate after manufacturing a mold for a diffraction grating light guide plate using the manufactured diffraction grating light guide plate as an intermediate mold, the inclination of the grid pattern of the diffraction grating light guide plate used as an intermediate mold is obtained by inverting. You can. Furthermore, when manufacturing a diffraction grating light guide plate after manufacturing a mold for a diffraction grating light guide plate using a diffraction grating light guide plate with the inclination of the grating pattern reversed as an intermediate mold, a grating pattern in the same direction as the first diffraction grating light guide plate can be implemented. there is.

Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those skilled in the art.

In order to perform inclined etching with plasma and create a depth gradient, it is necessary to precisely control the gradient at which the etching depth of the grid pattern changes. A shutter can be used to precisely control the tilt. The width (W) of the shutter is fixed at 70 mm, which is 100% of the size of the mesh portion, and the length (L) of the shutter is changed from 20 mm to 40 mm and plasma etched for 5 minutes to change the slope of the etch depth of the grid pattern. Confirmed.

Figure 13 is a graph showing the depth gradient according to the position of the etching substrate for plasma etching using a Faraday box without a shutter and shielded with a shutter having a length (L) of 30 mm according to an embodiment of the present invention. It's a degree. As shown in FIG. 5, when plasma etching is performed using the Faraday box of the present invention for 5 minutes without a shutter, non-uniform etching areas with high etching speed occur in two places. When plasma etching was performed using a Faraday box shielded with a shutter having a length (L) of 30 mm, it was confirmed that a change occurred in the vertical depth distribution at the 30 mm position of the etching substrate.

Accordingly, the slope of the etching depth was observed at a position of 40 mm to 55 mm from the etching substrate.

At this time, the etching substrate was prepared with a length of 30 mm and placed at a position between 30 mm and 60 mm on the x-axis of FIG. 13, and the etched depth of the etching substrate was between 30 mm and 52 mm on the x-axis of FIG. Measured.

Example 1

The etching substrate was prepared with a length of 30 mm, placed at a position between 30 mm and 60 mm on the x-axis of FIG. 13, and plasma etching was performed for 3 minutes and 30 seconds. At this time, a shutter with a length of 40 mm was placed at the bottom of the slope of the Faraday box. The etched depth of the etching substrate was measured at a position of 30 mm to 52 mm on the x-axis of FIG. 13.

Comparative Example 1

Plasma etching was performed under the same conditions as Example 1, except that the length of the shutter in Example 1 was 35 mm.

Comparative example 2

Plasma etching was performed under the same conditions as Example 1, except that the length of the shutter in Example 1 was 30 mm.

Figure 14 is a graph showing plasma etching using a Faraday box shielded with shutters having lengths of 30 mm, 35 mm, and 40 mm according to an embodiment of the present invention, and showing the depth gradient according to the position of each etching substrate. am. The target profile in FIG. 14 corresponds to the depth slope required for the diffraction light guide plate, and is required to have a slope of 35 degrees at the initial 15 mm (45 mm x-axis position in FIG. 14) position and a depth of 50 nm, and the final A depth gradient with a depth of 270 nm is required. It can be confirmed that plasma etching was performed with a shutter length of 40 mm (Example 1) that has a depth change slope similar to the target profile, that is, a depth gradient similar to the target profile.

Figure 15 shows plasma etching using a Faraday box shielded with shutters having lengths of 30 mm, 35 mm, and 40 mm according to an embodiment of the present invention, and depth gradients can be confirmed according to the positions of each etching substrate. This is an image observed with a scanning electron microscope (SEM). In Example 1, Comparative Example 1, and Comparative Example 2, the depth was measured at positions 37 mm, 43 mm, and 49 mm. The target depths at the above positions correspond to 55 nm, 100 nm, and 200 nm, respectively, and it can be seen from FIG. 15 that Example 1 with a shutter of 40 mm is closest to the target depth.

Therefore, the Faraday box and the plasma etching method using the same of the present invention can form a pattern portion having a pattern inclined inward of the etching substrate by providing a part of the etching substrate to the expanded portion, and the mesh portion has a specific length. It was confirmed that the depth gradient could be precisely controlled by arranging the shutter part of .

1: Cylindrical Faraday Box
3: Mesh part
5: bottom surface
7: Substrate for etching
9: support
11: bottom surface
13: inclined portion
15: Mesh part
17: Extension part
19: Substrate for etching
21: Shutter

Claims (19)

A Faraday box comprising a bottom surface, an inclined portion disposed at an angle to the bottom surface and having a mesh portion formed thereon, and an extension portion where the bottom surface extends outward from a lower end of the inclined portion. In claim 1,
A Faraday box, wherein the angle formed by the bottom surface and the inclined portion is 30° or more and 70° or less. In claim 1,
The Faraday box further includes a shutter on the mesh portion. Providing a substrate for etching on the bottom of the Faraday box of claim 1; and
A first pattern portion forming step of forming a first pattern portion by performing plasma etching on the etching substrate,
The step of providing the substrate for etching includes placing a portion of the substrate for etching in the expanded portion. In claim 4,
After the first pattern portion forming step,
A second pattern in which the etching substrate is provided on the bottom surface so that the portion where the first pattern portion of the etching substrate is formed is located in the expansion portion, and plasma etching is performed on the etching substrate to form a second pattern portion. A plasma etching method using a Faraday box, wherein the part forming step is performed. In claim 4 or claim 5,
The plasma etching method using a Faraday box, wherein the plasma etching is performed after shielding at least a portion of the mesh portion with a shutter. In claim 6,
A plasma etching method using a Faraday box, wherein the shutter shields 20% to 80% of the mesh portion. In claim 4,
A plasma etching method using a Faraday box, wherein the etching substrate is provided parallel to the bottom surface. In claim 4,
A plasma etching method using a Faraday box, wherein the etching substrate is a quartz substrate or a silicon wafer. In claim 4,
A plasma etching method using a Faraday box, wherein the mesh portion has a sheet resistance of 0.5 Ω/□ or more. In claim 4,
A plasma etching method using a Faraday box, wherein the mesh portion is formed by adsorbing fluorocarbon radicals on a metal mesh. In claim 4,
The plasma etching method includes adjusting the output of the plasma etching device to 0.75 kW or more and 4 kW or less. In claim 4,
The plasma etching is a plasma etching method using a Faraday box, which includes supplying a mixed gas containing a reactive gas and oxygen gas to the plasma etching device at a rate of 10 sccm or more and 75 sccm or less. In claim 13,
A plasma etching method using a Faraday box, wherein the oxygen gas flow content in the total flow rate of the mixed gas is 1% or more and 20% or less. In claim 4,
The etching substrate has a metal mask on the top,
A plasma etching method using a Faraday box, wherein the bottom surface of the Faraday box includes a metal having a lower ionization tendency than the metal mask. In claim 4,
The etching substrate has a metal mask on the top,
A plasma etching method using a Faraday box, wherein the bottom surface of the Faraday box contains metal 1 V or more higher than the standard reduction potential of the metal mask. In claim 4,
The etching substrate has a metal mask on the top,
A plasma etching method using a Faraday box, wherein the metal mask contains at least one of aluminum and chromium, and the bottom surface of the Faraday box contains copper. In claim 4,
A plasma etching method using a Faraday box, wherein the etching substrate on which the pattern portion is formed is a mold substrate for a diffraction grating light guide plate. In claim 4,
In the step of forming the pattern portion, the etching substrate is provided to be accommodated in the expansion portion and plasma etching is performed.