KR102548183B1 - Method for plasma etching process using faraday box - Google Patents

Abstract

The present invention relates to a plasma etching method capable of forming pattern portions having different depth gradients for each region on a substrate for etching using a Faraday box.

Description

Plasma etching method using a Faraday box {METHOD FOR PLASMA ETCHING PROCESS USING FARADAY BOX}

The present invention relates to a plasma etching method using a Faraday box.

Recently, as interest in display units that implement augmented reality (AR), mixed reality (MR), or virtual reality (VR) has increased, 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 using a diffraction phenomenon based on a wave property of light. The diffraction grating light guide plate includes a diffraction grating pattern capable of internally reflecting or total internally reflecting incident light to guide light incident on the diffraction grating light guide plate to a point.

Various methods are used to manufacture the diffraction grating light guide plate as described above, and generally, the diffraction grating light guide plate is manufactured through an imprinting method using a mold. In this case, a diffraction grating pattern may be formed by performing plasma etching on the substrate for etching, thereby manufacturing a mold for a diffraction grating light guide plate.

However, in the process of manufacturing a mold for a diffraction grating light guide plate by performing conventional plasma etching, it is difficult to precisely form a pattern portion having a depth gradient on an etching substrate.

Accordingly, there is a need for a technology capable of precisely forming a pattern portion having a depth gradient through a plasma etching process.

An object of the present invention is to provide a plasma etching method using a Faraday box capable of precisely forming a pattern portion having a depth gradient.

An exemplary embodiment of the present invention includes providing a substrate for etching in a Faraday box having a mesh portion on an upper surface thereof; After shielding at least a portion of the mesh portion with a shutter, performing plasma etching on the substrate for etching; and forming a pattern portion on the substrate for etching by moving the shutter from the central portion of the Faraday box along the outer portion and performing plasma etching, wherein the Faraday box includes: , The speed at which the shutter moves is changed, and the depth of the pattern portion is gradually changed from one side of the substrate for etching to the other side, providing a plasma etching method using a Faraday box.

A plasma etching method using a Faraday box according to an exemplary embodiment of the present invention may precisely form pattern portions having different depth gradients for each region of a substrate for etching.

Effects of the present invention are not limited to the above-mentioned effects, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and accompanying drawings.

1 shows the result of measuring the etching rate according to the distance from the mesh part of the Faraday box to the substrate for etching.
2 is a diagram schematically illustrating a plasma etching method using a Faraday box according to an exemplary embodiment of the present invention.
FIG. 3 is a diagram schematically illustrating a method of plasma etching a substrate for etching in which first to third regions are divided according to an exemplary embodiment of the present invention by using a Faraday box.
4 is a diagram schematically illustrating a plasma gradient etching method using a Faraday box according to an exemplary embodiment of the present invention.
5 is a view showing the initial position of a shutter in the plasma etching method using a Faraday box according to Example 1 of the present invention.
6 is a graph showing the depth of the pattern part according to the distance from one side of the quartz substrate having the pattern part manufactured in Comparative Example 1.
FIG. 7A is a SEM photograph of a cross section of a quartz substrate having a pattern part prepared in Example 1 of the present invention, and FIG. 7B is a SEM photograph of a cross section of a quartz substrate provided with a pattern part manufactured in Comparative Example 1. .

Throughout the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

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

Throughout this specification, the terms "step of (doing)" or "step of" as used do not mean "step for".

In the present invention, the Faraday box means an enclosed space made of conductors, and when the Faraday box is installed in the plasma, a sheath is formed on the outer surface of the box to maintain a constant electric field inside. At this time, if the upper surface of the Faraday box is formed as a mesh portion, a sheath is formed along the surface of the mesh portion. Therefore, when plasma etching is performed using a Faraday box, ions accelerated in a direction perpendicular to the sheath formed horizontally on the surface of the mesh part are incident to the inside of the Faraday box, and then maintain the orientation at the time of incident and It reaches up to and etch the substrate. Furthermore, the surface of the substrate for mold inside the Faraday box in the present invention may be fixed in a horizontal or inclined state with respect to the mesh surface, and since ions are incident in a direction perpendicular to the mesh surface, Etching in an inclined direction is possible. The Faraday box may be a conductor box having a top surface of a conductive mesh part. An etching direction of the plasma etching may be a direction perpendicular to a surface of the mesh portion of the Faraday box.

In the case of plasma etching using a Faraday box, ions passing through the mesh collide with neutral particles present inside the Faraday box while moving toward the substrate and lose kinetic energy. It tends to be inversely proportional to the negative distance. That is, the closer the ion is to the mesh portion, the higher the etching rate is, and the farther the mesh portion is, the lower the etching rate is.

The present inventors studied a plasma etching method using a Faraday box having the above-described characteristics, and specifically studied a method for precisely forming a pattern portion having a depth gradient, and developed the following invention.

Hereinafter, this specification will be described in more detail.

An exemplary embodiment of the present invention includes providing a substrate for etching in a Faraday box having a mesh portion on an upper surface thereof; After shielding at least a portion of the mesh portion with a shutter, performing plasma etching on the substrate for etching; and forming a pattern portion on the substrate for etching by moving the shutter from the central portion of the Faraday box along the outer portion and performing plasma etching, wherein the Faraday box includes: , The speed at which the shutter moves is changed, and the depth of the pattern portion is gradually changed from one side of the substrate for etching to the other side, providing a plasma etching method using a Faraday box.

A plasma etching method using a Faraday box according to an exemplary embodiment of the present invention may precisely form pattern portions having different depth gradients for each region of a substrate for etching. In addition, the plasma etching method using the Faraday box can suppress formation of acicular structures in the process of forming the pattern portion.

According to an exemplary embodiment of the present invention, the substrate for etching may be a quartz substrate or a silicon wafer. Plasma etching, specifically, in the etching process using inductively coupled plasma reactive ion etching equipment (ICP-RIE), the self-masking mechanism causes the formation of needle-like structures (grass) with low reflectivity in the etching area. may occur. However, according to one embodiment of the present invention, by using a quartz substrate or a silicon wafer as the substrate for etching, it is possible to effectively suppress the formation of needle-like structures during the process of etching the pattern portion on one surface of the substrate for etching. .

According to one embodiment of the present invention, a metal mask including at least one of aluminum and chromium and having an opening may be provided on one surface of the substrate for etching. Specifically, the metal mask may be made of aluminum. A substrate for etching having a metal mask on one surface may be placed in the Faraday box. Plasma etching may be performed on a region of the substrate for etching exposed by the opening of the metal mask to form a pattern portion on the substrate for etching.

Also, the number of openings provided in the metal mask may be two or more. That is, two types of pattern parts may be formed on the substrate for etching using a metal mask having two or more openings.

According to an exemplary embodiment of the present invention, a pattern portion may be formed on one surface of the substrate for etching by plasma-etching one surface of the substrate for etching using a Faraday box having a mesh portion on an upper surface thereof. When the mesh part is plasma etched, a sheath may be formed by attracting free electrons from a surface in contact with plasma. In addition, the mesh portion may have conductivity, and through this, ions having a positive charge may be attracted and accelerated. Furthermore, the mesh portion may be provided flat on one surface of the Faraday box, and if there is a curved portion, an etching rate at the curved portion may be locally varied.

According to one embodiment of the present invention, the mesh portion may have a sheet resistance of 0.5 Ω/□ or more. Specifically, the sheet resistance of the mesh portion may be 0.5 Ω/□ or more and 100 Ω/□ or less. When the substrate for etching is plasma-etched using a conventional Faraday box, a highly etched region and a low-etched region are irregularly mixed for each position of the Faraday box, resulting in a problem in that the accuracy of plasma etching is lowered. On the other hand, according to an exemplary embodiment of the present invention, by adjusting the sheet resistance of the mesh portion to the above range, it is possible to constantly form a high etch region and a low etch region in the Faraday box during plasma etching. That is, the pattern portion may be precisely etched on the substrate for etching. In addition, when the sheet resistance of the mesh portion is within the above-mentioned range, it is possible to improve the etching efficiency while reducing the manufacturing cost of the Faraday box.

According to an exemplary embodiment of the present invention, the mesh portion may be one in which fluorocarbon radicals are adsorbed on a metal mesh. Specifically, the fluorocarbon radical may be -CF, -CF ₂ , -CF ₃ or -C ₂ F _x (x is an integer from 1 to 5). More specifically, during plasma etching of the mesh portion of the Faraday box, fluorocarbon radicals may be adsorbed to the mesh portion by etching and surface polymerization by F radicals. In addition, as the fluorocarbon radicals are adsorbed on a conductive material such as metal, the mesh portion may have a sheet resistance within the aforementioned range.

According to one embodiment of the present invention, the mesh portion may use a mesh of stainless material. Specifically, #200 (pitch 125 μm, wire diameter 50 μm, aperture ratio 36%) made of SUS304 may be used. However, the material of the mesh part is not limited, and the mesh part may be made of Al, Cu, W, Ni, Fe, and an alloy containing at least two of these materials. In addition, the porosity and lattice size of the mesh can be freely adjusted according to the purpose of etching.

According to an exemplary embodiment of the present invention, the separation distance between the substrate for etching and the mesh part may be 1 mm or more and 35 mm or less. Specifically, the separation distance between the substrate for etching and the mesh part is 3 mm or more and 32 mm or less, 6 mm or more and 30 mm or less, 8.5 mm or more and 25 mm or less, 10 mm or more and 15 mm or less, 8 mm or more and 12 mm or less, or 12.5 mm or more and 20 mm or less.

The present inventors installed a support having an inclined surface of 40° in a Faraday box, provided a substrate for etching on the support, and then performed plasma etching using ICP-RIE (Oxford PlasmaLab system 100). At this time, as a reactive gas, O ₂ and C ₄ F ₈ were mixed at a ratio of 2:48 and supplied at a flow rate of 50 sccm. Further, as etching conditions, the etching was performed for 3 minutes under RF power of 150 W, ICP power of 2 kW, and operating pressure of 7 to 10 mTorr. Through this, the etching rate according to the distance from the mesh part of the Faraday box was measured, and the result is shown in FIG. 1.

1 shows the result of measuring the etching rate according to the distance from the mesh part of the Faraday box to the substrate for etching. According to the results of FIG. 1, when the distance between the substrate for etching and the mesh part exceeds 35 mm, it can be confirmed that the etching rate is significantly reduced. Therefore, considering the etching efficiency, the distance between the substrate for etching and the mesh part It can be adjusted to 35 mm or less. In addition, when the distance between the mesh part and the substrate for etching is less than about 1 mm, it has been found that the mesh lattice pattern of the mesh part acts like an etching mask and remains in the etching area. Accordingly, it may be necessary to maintain a separation distance of at least 1 mm from the mesh portion of the substrate for etching.

2 is a diagram schematically illustrating a plasma etching method using a Faraday box according to an exemplary embodiment of the present invention. Specifically, FIG. 2 shows that the support 300 is provided in the Faraday box 100 having the mesh portion 110 on the upper surface, the substrate 200 for etching is positioned on the support 300, and the mesh portion ( 110) is shielded by the shutter 120, and plasma etching is performed on the substrate 200 for etching. In addition, FIG. 2 shows a pattern having a depth gradient by moving the shutter 120 from the center of the Faraday box 100 to the outside (direction of the dotted line arrow) and performing plasma etching on the substrate 200 for etching. It represents the creation of wealth.

According to one embodiment of the present invention, after shielding at least a portion of the mesh portion with a shutter, plasma etching may be performed on the substrate for etching. At this time, the shutter may be provided on the mesh part near the central part of the Faraday box. Referring to FIG. 2 , a shutter 120 is provided on the mesh portion 110 near the central portion of the Faraday box 100 to shield at least a portion of the mesh portion 110 and cover the substrate 200 for etching. Plasma etching can be performed on At this time, the position of the shutter 120 may be set such that a portion of one side of the etching substrate 200 adjacent to the outer portion of the Faraday box 100 is not shielded. In addition, the position of the shutter may be set so that the entire surface of the substrate for etching is shielded by the shutter.

According to an exemplary embodiment of the present invention, by shielding a portion of the mesh portion of the Faraday box using a shutter, in an etching area adjacent to the area shielded by the shutter, an etching rate change width according to an increase in the distance from the mesh portion to the substrate for etching. can be greatly adjusted. That is, a pattern portion having a depth gradient may be easily formed on one surface of the substrate for etching by shielding a portion of the mesh portion with a shutter and greatly adjusting the etching rate variation range.

According to one embodiment of the present invention, the pattern portion may be formed on the substrate for etching by moving the shutter from the central portion to the outer portion of the Faraday box and performing plasma etching. That is, the shutter located near the central portion of the Faraday box may be moved to the vicinity of the outer portion of the Faraday box. Referring to FIG. 2 , the shutter 120 provided on the mesh part 110 is moved from the center of the Faraday box 100 along the outer side (direction of the dotted line arrow), and one side of the etching substrate 200 can be plasma etched. Through this, it is possible to easily form a substrate for etching provided with a pattern portion whose depth is gradually changed from one side of the substrate for etching to the other. Specifically, referring to FIG. 2 , along the direction from one side (A) to the other side (B) of the substrate 200 for etching, the depth of the pattern portion P provided on the substrate 200 for etching is gradually reduced. can

According to an exemplary embodiment of the present invention, the forming of the pattern part may include moving the shutter from the center of the Faraday box to the outer side so that the shutter moves from one side of the substrate for etching to the other side of the substrate for etching. The method may include sequentially opening one side of the substrate to form a pattern portion having a gradual change in depth from one side of the substrate to the other side of the substrate for etching on one side of the substrate for etching.

According to an exemplary embodiment of the present invention, a moving speed of the shutter may be changed in a direction from the central part to the outer part of the Faraday box. Specifically, the shutter may move on the mesh part along a direction from the central part to the outer part of the Faraday box, and the moving speed of the shutter may gradually increase. Through this, it is possible to easily form a pattern portion having a different depth gradient for each region of the substrate for etching.

According to an exemplary embodiment of the present invention, the forming of the pattern part may include dividing first to third regions on the substrate for etching along a direction from one side of the substrate for etching to the other side of the substrate for etching, and It may include forming a first pattern part to a third pattern part on the first to third regions of A distance from one side of the substrate for etching to the other side may be divided into three equal parts to divide first to third regions, which are virtual regions, on one surface of the substrate for etching, and the first region through a plasma etching process. A first pattern part may be formed on the surface, a second pattern part may be formed on the second area, and a third pattern part may be formed on the third area. Also, depending on the design, the first to third regions may have the same or different sizes.

FIG. 3 is a diagram schematically illustrating a method of plasma etching a substrate for etching in which first to third regions are divided according to an exemplary embodiment of the present invention by using a Faraday box. Specifically, FIG. 3 shows the shutter 120 on the first region R ₁ , the second region R ₂ , and the third region R ₃ partitioned along the direction from one side of the substrate 200 for etching to the other side. It schematically shows forming the first pattern part to the third pattern part on the first region (R ₁ ) to the third region (R ₃ ) of the substrate 200 for etching by moving the substrate 200 for etching.

According to an exemplary embodiment of the present invention, a depth gradient is formed on the first to third regions by changing a moving speed of the shutter on the first to third regions partitioned on one surface of the substrate for etching. Different pattern parts can be formed more precisely. In addition, the area partitioned on one surface of the substrate for etching is not limited to the first to third areas, and for example, the first to fourth areas are partitioned on one surface of the substrate for etching, and the depth The first to fourth pattern portions having different gradients may be formed on each region.

According to an exemplary embodiment of the present invention, a moving speed of the shutter on the first region is greater than 0 mm/min and less than or equal to 40 mm/min, and the first pattern part may have a depth gradient of 250 nm to 500 nm. . Specifically, the moving speed of the shutter on the first region is 1 mm/min or more and 35 mm/min or less, 5 mm/min or more and 30 mm/min or less, 7 mm/min or more, 25 mm/min or less, and 10 mm /min or more and 20 mm/min or less, 1 mm/min or more and 15 mm/min or less, or 20 mm/min or more and 38 mm/min or less.

Referring to FIG. 3 , the moving speed of the shutter 120 on the first region R ₁ is when the tip of the shutter 120 is located on the first region R ₁ of the substrate 200 for etching. , The speed at which the shutter R ₁ moves from the center to the outer side of the Faraday box 100 may mean.

According to an exemplary embodiment of the present invention, the first pattern portion 250 nm to 500 nm, 270 nm to 480 nm, 300 nm to 450 nm, 350 nm to 400 nm, 260 nm to 320 nm per 5 mm of length of the substrate for etching nm, 340 nm to 420 nm, or 430 nm to 490 nm. The first pattern unit may include a plurality of grid patterns, the depths of each of the plurality of grid patterns may be different from each other, and the etching depth of each of the plurality of grid patterns may be within any one of the aforementioned ranges. Also, an average depth of the plurality of grating patterns may be one of the aforementioned depth gradients.

By adjusting the movement speed of the shutter in the first region to the above range, the first pattern portion having the depth gradient range may be formed on one surface of the substrate for etching. However, the depth gradient of the first pattern part is not limited to the above range, and the depth gradient of the first pattern part can be controlled by adjusting the ICP power of the plasma etching device, the distance between the etching substrate and the mesh part, and the like. can

According to one embodiment of the present invention, the moving speed of the shutter on the second area is greater than 40 mm/min and less than or equal to 200 mm/min, and the second pattern part may have a depth gradient of 100 nm to 350 nm. . Specifically, the moving speed of the shutter on the second region is 45 mm/min or more and 180 mm/min or less, 60 mm/min or more and 160 mm/min or less, 90 mm/min or more and 150 mm/min or less, 50 mm /min or more and 110 mm/min or less, or 120 mm/min or more and 190 mm/min or less.

According to an exemplary embodiment of the present invention, the second pattern portion 100 nm to 350 nm, 120 nm to 330 nm, 150 nm to 300 nm, 180 nm to 250 nm, 110 nm to 190 nm per 5 mm of length of the substrate for etching nm, 210 nm to 260 nm, or 280 nm to 340 nm. The second pattern unit may include a plurality of grid patterns, the depths of each of the plurality of grid patterns may be different from each other, and the etching depth of each of the plurality of grid patterns may be within any one of the aforementioned ranges. Also, an average depth of the plurality of grating patterns may be one of the aforementioned depth gradients. By adjusting the movement speed of the shutter in the second region to the above-described range, a second pattern portion having a depth gradient within the above-described range may be formed on one surface of the substrate for etching.

According to an exemplary embodiment of the present invention, a moving speed of the shutter on the third region is greater than 200 mm/min and less than or equal to 400 mm/min, and the third pattern portion may have a depth gradient of 0 nm to 200 nm. . Specifically, the moving speed of the shutter on the third region is 210 mm/min or more and 380 mm/min or less, 230 mm/min or more and 350 mm/min or less, 260 mm/min or more and 310 mm/min or less, 220 mm /min or more and 270 mm/min or less, or 300 mm/min or more and 390 mm/min or less.

According to an exemplary embodiment of the present invention, the third pattern portion has a thickness of 0 nm to 200 nm, 5 nm to 180 nm, 20 nm to 150 nm, 50 nm to 100 nm, and 1 nm to 40 nm per 5 mm of the length of the substrate for etching. nm, 70 nm to 130 nm, or 150 nm to 190 nm depth gradient. The third pattern unit may include a plurality of grid patterns, the depths of each of the plurality of grid patterns may be different from each other, and the etching depth of each of the plurality of grid patterns may be within any one of the aforementioned ranges. Also, an average depth of the plurality of grating patterns may be one of the aforementioned depth gradients. By adjusting the moving speed of the shutter in the third region to the above-described range, a third pattern portion having a depth gradient within the above-described range may be formed on one surface of the substrate for etching.

However, the depth gradient of the second pattern part and the third pattern part is not limited to the above range, and the second pattern part and the second pattern part and A depth gradient of the third pattern portion may be controlled.

According to an exemplary embodiment of the present invention, by adjusting the moving speed of the shutter in the first to third regions within the above-described range, the first to third pattern portions having different depth gradients are more visible on each region. can be precisely formed. In addition, by adjusting the movement speed of the shutter in the first to third regions within the above-described range, the formation of acicular structures in the plasma etching process may be more suppressed.

In addition, the movement speed of the shutter in the first to third regions may be appropriately adjusted according to the ICP power of the plasma etching apparatus. That is, by appropriately adjusting the moving speed of the shutter according to the ICP power of the plasma etching apparatus, it is possible to more precisely form a pattern portion having a different depth gradient on one surface of the substrate for etching, and suppress the formation of acicular structures. can do.

According to one embodiment of the present invention, the substrate for etching may be inclined on the bottom surface of the Faraday box. By providing the substrate for etching at an angle to the bottom surface of the Faraday box, an inclined pattern portion having a depth gradient may be formed on the substrate for etching.

4 is a diagram schematically illustrating a plasma gradient etching method using a Faraday box according to an exemplary embodiment of the present invention. 4 is provided with a support 300 having an inclined surface in a Faraday box 100 having a mesh portion 110 on the upper surface, placing a substrate 200 for etching on the support 300, and placing the mesh portion ( 110) is shielded by the shutter 120, and plasma gradient etching is performed on the substrate 200 for etching. 4 shows that the shutter 120 is moved from the center of the Faraday box 100 along the outer side (direction of the dotted line arrow), and plasma gradient etching is performed on the etching substrate 200 to have a depth gradient. It shows that the inclined pattern part P is formed.

According to an exemplary embodiment of the present invention, an inclination angle of the support with respect to the bottom surface of the Faraday box may be 0° or more and 60° or less, or 35° or more and 45° or less. An inclination angle of the pattern portion may be adjusted by adjusting an inclination angle of the support.

By adjusting the inclination angle of the support to the above range, the average inclination angle of the pattern portion may be adjusted to 0 ° to 55 ° or 30 ° to 40 °. For example, when the inclination angle of the support is adjusted to 35 °, the minimum inclination angle of the pattern part may be adjusted to 27 °, the maximum inclination angle to 36 °, and the average inclination angle to 33 °. In addition, when the inclination angle of the support is adjusted to 40 °, the minimum inclination angle of the pattern part may be adjusted to 32 °, the maximum inclination angle to 40 °, and the average inclination angle to 36 °.

According to an exemplary embodiment of the present invention, the plasma etching may include adjusting the ICP power of the plasma etching apparatus to 0.1 kW or more and 4 kW or less, and the RF power to 10 W or more and 200 W or less. Specifically, the ICP power of the plasma etching device may be adjusted to 0.2 kW to 3.8 kW, 0.5 kW to 3.5 kW, 0.75 kW to 3.0 kW, 1.0 kW to 2.5 kW, or 1.5 kW to 2.0 kW. . In addition, the RF power of the plasma etching device may be adjusted to 10 W to 200 W, 20 W to 180 W, 50 W to 150 W, or 70 W to 120 W.

By adjusting the ICP power and RF power of the plasma etching device to the above ranges, it is possible to precisely form a pattern portion having a depth gradient on the substrate for etching, and to suppress the occurrence of acicular structures during plasma etching of the substrate for etching. can do.

According to one embodiment of the present invention, the plasma etching may include adjusting an operating pressure to 1 mtorr or more and 30 mtorr or less. Specifically, the operating pressure may be adjusted to 2 mtorr or more and 28 mtorr or less, 5 mtorr or more and 28 mtorr or less, 7 mtorr or more and 25 mtorr or less, 10 mtorr or more and 20 mtorr or less, or 12 mtorr or more and 18 mtorr or less.

According to an exemplary embodiment of the present invention, the plasma etching may include supplying a mixed gas including a reactive gas and an oxygen gas to a plasma etching apparatus at a concentration of 10 sccm or more and 200 sccm or less. Specifically, in the plasma etching process, the mixed gas may be supplied to the plasma etching apparatus at 20 sccm or more and 180 sccm or less, 40 sccm or more and 150 sccm or less, 60 sccm or more and 130 sccm or less, and more specifically, 15 sccm or more 75 sccm or more. sccm or less, 25 sccm or more and 70 sccm or less, 30 sccm or more and 70 sccm or less, 40 sccm or more and 60 sccm or less, or 45 sccm or more and 55 sccm or less.

By adjusting the supply flow rate of the mixed gas containing the reactive gas and the oxygen gas within the above range, the precision of the etching process of the pattern part can be improved, and the occurrence of acicular structures can be more suppressed in the process of patterning the substrate for etching. can

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

According to an exemplary embodiment of the present invention, in the plasma etching, a mixed gas having an oxygen gas flow rate content of 1% or more and 20% or less with respect to the total flow rate of the mixed gas may be supplied to the plasma etching device. 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 flow rate of the oxygen gas in the flow rate of the mixed gas is within the above range, the amount of acicular structures generated on the substrate for etching during the plasma etching process can be effectively reduced.

According to an exemplary embodiment of the present invention, the substrate for etching having the pattern portion may be a mold substrate for a diffraction grating light guide plate. Specifically, the pattern portion formed on the substrate for etching may be a pattern of a mold for a diffraction grating light guide plate.

An exemplary embodiment of the present invention includes preparing a mold for a diffraction grating light guide plate in which a pattern portion is formed by using the plasma etching method using the Faraday box; coating a resin composition on one surface of the mold for the diffraction grating light guide plate on which the pattern portion is formed; and curing the resin composition.

According to an exemplary embodiment of the present invention, the resin composition may be used without limitation as long as it is a resin composition generally used in the art. Furthermore, the step of applying the resin composition may be performed using a coating method commonly used in the art, such as spin coating, dip coating, and drop casting. In addition, as a method of curing the resin composition, a curing method commonly used in the art may be used without limitation. For example, a photocuring method may be used when a photocurable resin composition is used, and a heat curing method may be used when a thermosetting resin composition is used.

According to an exemplary embodiment of the present invention, the diffraction grating light guide plate may be directly used as a diffraction grating light guide plate. In addition, a final product may be manufactured by using the diffraction grating light guide plate as an intermediate mold and replicating it. Specifically, when a diffraction grating light guide plate is manufactured again using the prepared diffraction grating light guide plate as an intermediate mold, a slope of a grating pattern of the diffraction grating light guide plate used as an intermediate mold may be reversed. Furthermore, when the diffraction grating light guide plate is manufactured after manufacturing a mold for the diffraction grating light guide plate by using the diffraction grating light guide plate in which the gradient of the grating pattern is reversed as an intermediate mold, the grating pattern in the same direction as the first diffraction grating light guide plate can be implemented. there is.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present invention to those skilled in the art.

Example One

A Faraday box having a sheet resistance of the mesh portion of 0.5605 Ω/□ and a bottom surface of a stainless steel (SUS304) plate was prepared. And, the Faraday box was provided in an inductively coupled plasma reactive ion etching equipment (ICP-RIE) (Oxford PlasmaLab system 100).

Al was deposited on a quartz substrate having a thickness of 2 mm to form an Al layer having a thickness of 50 nm. Then, after spin-coating the photoresist on the Al layer, using a photomask having a pitch of 400 nm to develop the photoresist by UV curing, the Al layer is selectively etched, and a pitch of 400 nm, 200 nm A substrate for etching was prepared by forming an Al metal mask having a pattern having a width of on a quartz substrate.

Thereafter, a support stand made of Al material having a height of 30 mm was provided to the Faraday box, and a quartz substrate was placed on the support stand. At this time, the minimum separation distance between one surface of the quartz substrate and the mesh portion was about 5 mm.

5 is a view showing the initial position of a shutter in the plasma etching method using a Faraday box according to Example 1 of the present invention. As shown in FIG. 5, the shutter 120 is provided on the mesh portion 110 of the Faraday box 100, and the distance d1 between the end of the shutter 120 and the end of the substrate 200 for etching is 1 mm. was set to be

Then, plasma etching was performed using ICP-RIE (Oxford PlasmaLab system 100), and as a reactive gas, O ₂ and C ₄ F ₈ were mixed at a ratio of 2:48 and supplied at a flow rate of 50 sccm. Further, as etching conditions, the RF power was set to 150 W, the ICP power to 2 kW, and the operating pressure to 7 mTorr.

Then, as shown in FIG. 5, the shutter 120 was moved at intervals of 1.9 mm from the center of the Faraday box 100 along the outer side (in the direction of the arrow of the dotted line in FIG. 5), and on one side (A) of the substrate for etching. According to the distance from one side (A) of the substrate for etching in the direction of the other side (B), the moving speed of the shutter and the depth of the pattern portion of the prepared substrate for etching are shown in Table 1 below.

Referring to Table 1, it was confirmed that pattern portions having different depth gradients can be easily formed on the substrate for etching by adjusting the moving speed of the shutter.

comparative example One

The same Faraday box and substrate for etching as in Example 1 were prepared, and the substrate for etching was etched in the same manner as in Example 1, except that the mesh portion was not shielded using a shutter.

6 is a graph showing the depth of the pattern part according to the distance from one side of the quartz substrate having the pattern part manufactured in Comparative Example 1. Referring to FIG. 6 , unlike Example 1 of the present invention, in the case of Comparative Example 1 in which a plasma etching process was performed without using a shutter, it was confirmed that the pattern portion did not have a depth gradient.

pattern part Section observation

FIG. 7A is a SEM photograph of a cross section of a quartz substrate having a pattern part prepared in Example 1 of the present invention, and FIG. 7B is a SEM photograph of a cross section of a quartz substrate provided with a pattern part manufactured in Comparative Example 1. .

Referring to FIG. 7A , in the case of Example 1 in which plasma etching is performed while changing the moving speed of the shutter while moving the shutter from the center of the Faraday box to the outer side, the pattern portion is changed according to the distance from one side of the quartz substrate. It was confirmed that the depth was different. On the other hand, referring to FIG. 7B , in Comparative Example 1 in which plasma etching was performed without a shutter, it was confirmed that the depth gradient of the pattern portion was not formed according to the distance from one side of the quartz substrate.

Accordingly, it can be seen that the plasma etching method using a Faraday box according to an exemplary embodiment of the present invention can easily form a pattern portion having a depth gradient on a substrate for etching.

100: Faraday box
110: mesh part
120: shutter
200: substrate for etching
300: support

Claims (15)

providing a substrate for etching in a Faraday box provided on an upper surface of the mesh unit;
After shielding at least a portion of the mesh portion with a shutter, performing plasma etching on the substrate for etching; and
Forming a pattern portion on the substrate for etching by moving the shutter from the center of the Faraday box to the outer portion and performing plasma etching;
The speed at which the shutter moves is changed from the center to the outer portion of the Faraday box,
Plasma etching method using a Faraday box in which the depth of the pattern portion is gradually changed in a direction from one side of the substrate for etching to the other side.
The method of claim 1,
Forming the pattern part,
Partitioning first to third regions on the substrate for etching along a direction from one side of the substrate for etching to the other side;
A plasma etching method using a Faraday box comprising forming first pattern parts to third pattern parts on the first to third regions of the substrate for etching, respectively.
The method of claim 2,
The movement speed of the shutter on the first region is greater than 0 mm/min and less than or equal to 40 mm/min,
Plasma etching method using a Faraday box in which the depth of the pattern constituting the first pattern portion is gradually changed from 250 nm to 500 nm.
The method of claim 2,
The movement speed of the shutter on the second area is greater than 40 mm/min and less than or equal to 200 mm/min,
Plasma etching method using a Faraday box in which the depth of the pattern constituting the second pattern portion is gradually changed from 100 nm to 350 nm.
The method of claim 2,
The movement speed of the shutter on the third region is greater than 200 mm/min and less than or equal to 400 mm/min,
Plasma etching method using a Faraday box in which the depth of the pattern constituting the third pattern portion is gradually changed from 0 nm to 200 nm.
The method of claim 1,
Plasma etching method using a Faraday box in which the separation distance between the substrate for etching and the mesh part is 1 mm or more and 35 mm or less.
The method of claim 1,
The plasma etching is a plasma etching method using a Faraday box comprising adjusting the ICP power of the plasma etching device to 0.1 kW or more and 4 kW or less, and the RF power to 10 W or more and 200 W or less.
The method of claim 1,
The plasma etching is a plasma etching method using a Faraday box comprising adjusting an operating pressure to 1 mTorr or more and 30 mTorr or less.
The method of claim 1,
The plasma etching method using a Faraday box comprising supplying a mixed gas containing a reactive gas and an oxygen gas to a plasma etching apparatus at 10 sccm or more and 200 sccm or less.
The method of claim 9,
Plasma etching method using a Faraday box wherein the content of the oxygen gas flow rate is 1% or more and 20% or less with respect to the total flow rate of the mixed gas.
The method of claim 1,
Plasma etching method using a Faraday box in which the mesh portion has a sheet resistance of 0.5 Ω/□ or more.
The method of claim 1,
The mesh portion is a plasma etching method using a Faraday box in which fluorocarbon radicals are adsorbed on a metal mesh.
The method of claim 1,
Plasma etching method using a Faraday box, wherein a metal mask including at least one of aluminum and chromium and having an opening is provided on one surface of the substrate for etching.
The method of claim 1,
The plasma etching method using a Faraday box in which the substrate for etching is inclined on the bottom surface of the Faraday box.
The method of claim 1,
The plasma etching method of claim 1, wherein the substrate for etching having the pattern portion is a mold substrate for a diffraction grating light guide plate, using a Faraday box.

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