JP6008131B2 - Manufacturing method of optical member - Google Patents

Description

  The present invention relates to a method for producing an optical member, such as an optical film, a lens, or a display, having an optical function such as antireflection on the surface.

  Conventionally, a photolithography technique and an electron beam drawing method generally used in a semiconductor manufacturing process have been applied to fine processing of a structure. The photolithographic method, which is one of the pattern transfer technologies for realizing fine processing, is approaching the limit of the lithography technology because the processing dimension has approached the wavelength of the light source of light exposure as the pattern is miniaturized.

  Therefore, an electron beam drawing (EB drawing) apparatus, which is a kind of charged particle beam apparatus, has come to be used in order to achieve further miniaturization and higher precision. However, while miniaturizing the pattern and increasing the number of drawing, there is a disadvantage that the manufacturing cost of the apparatus becomes high, such as an increase in size of the apparatus and a highly accurate control mechanism.

On the other hand, Patent Documents 1 and 2 disclose techniques for forming a fine uneven pattern at a low cost.
In Patent Document 1, a predetermined concavo-convex pattern is transferred by embossing a mold having an inverted concavo-convex pattern obtained by inverting a concavo-convex pattern to be formed on a substrate against a resist film layer formed on the surface of the substrate. To do.

Further, according to the nanoimprint technique described in Patent Document 2, it is possible to form a fine uneven pattern of 25 nm or less on the resist film layer by means of die transfer using a silicon wafer as a mold.
By the way, in recent years, for example, a large area and high performance of an optical component are desired as represented by a liquid crystal display. As a structure for viewing an image on a liquid crystal display, a structure in which a light guide plate and a retardation film for adjusting the refractive index of light are incorporated is known. These light guide plates, retardation films, and the like need to have a fine structure in which a fine uneven pattern is transferred to the surface. For example, in a liquid crystal display, if this fine structure is to be realized, a large-sized fine structure having a single piece and no seam is required.
However, as in Patent Document 1 and Patent Document 2, in order to manufacture a large-area fine structure as a single unit, the apparatus cost and manufacturing cost for manufacturing a large-area original plate become enormous. By arranging a plurality of individual basic microstructures side by side, a microscopic structure having a large area with little influence of seams is formed (for example, see Patent Document 3).

  In Patent Document 3, as shown in FIG. 9, a basic fine structure 62 having a concavo-convex pattern 61 formed at the tip and an undercut at the end is arranged side by side on a substrate 63, and an adhesive layer 64 is arranged. It is made to adhere through. A plurality of the basic fine structures 62 are arranged on the base material 63 in a state where the gaps Ds are provided, and the fine structure 65 is configured. Using the fine structure 65 configured as described above, a fine uneven pattern is transferred to the surface of a light guide plate, a retardation film or the like.

US Pat. No. 5,259,926 US Pat. No. 5,772,905 JP 2010-80670 A (FIG. 1)

  However, in the conventional technique, by repeating the nanoimprint technique, the fine structure can be enlarged, but a portion where no pattern is formed is generated between the transferred patterns. There is a problem that a portion where the pattern is not formed is generated, becomes a joint, and does not satisfy the performance.

  An object of the present invention is to provide a method for manufacturing an optical member, in which a plurality of basic microstructure patterns can be arranged and connected with high accuracy in consideration of the problems of a conventional method for manufacturing a microstructure.

  The method for producing an optical member of the present invention is an optical member having a continuous fine structure by repeatedly transferring a microstructure mold having a microstructure on the surface to a reactive curable resin disposed on a substrate, A first application step of applying a reactive curable resin on the substrate; a first adhesion step of bringing the reactive curable resin into close contact with the surface of the microstructured mold by bringing the substrate and the microstructured mold closer to each other; The reactive curable resin corresponding to the first region of the microstructured mold in the first adhesion step is cured, and the reactive curable resin corresponding to the second region of the microstructured mold is uncured. A first curing step that remains in a state, a first mold release step for releasing the microstructured mold from the cured and uncured resin, and an uncured resin corresponding to the second region. A second application step of applying a reactive curable resin on the substrate; A transfer position changing step for moving the transfer position so that a part of the microstructured mold overlaps with the cured resin in the first curing step; and the reactive curable resin applied in the second coating step. A second contact step of moving the substrate and the microstructured mold relative to each other so that the reactive curable resin is in close contact with the surface of the microstructured mold sandwiched between the substrate and the microstructured mold; Curing the reactive curable resin corresponding to the third region of the microstructured mold in the process, leaving the reactive curable resin corresponding to the fourth region of the microstructured mold in an uncured state; It has 2 hardening processes and the 2nd mold release process which releases the said microstructure metal mold from the resin of a hardening state and an unhardened state, It is characterized by the above-mentioned.

  The second coating step, the transfer position changing step, the second adhesion step, the second curing step, and the second release step are repeated.

  According to the present invention, a large-area microstructure having no visual discontinuity is obtained by reducing transfer pressure applied to the end of a small-area microstructure mold and repeating the transfer while controlling the resin flow. Can be obtained.

Schematic of the manufacturing apparatus in Embodiment 1 of the present invention (A) Schematic side view of mold and (b) Schematic plan view of mold in Embodiment 1 of the present invention (A) Cross-sectional view during pressing and (b) Cross-sectional view during ultraviolet irradiation in the single transfer process according to Embodiment 1 of the present invention (A) A side view of a single transfer area and (b) an enlarged plan view showing a resin light-cured area and an uncured resin area of a resin on a substrate in Embodiment 1 of the present invention. Step Diagram of Multiple Transfer Process in Embodiment 1 of the Present Invention Plan view of substrate repeatedly transferred in Embodiment 1 of the present invention Process chart of multiple transfer process of comparative example Schematic of the manufacturing apparatus in Embodiment 2 of the present invention Sectional drawing of the fine structure described in Patent Document 3

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
(Embodiment 1)
In the first embodiment, as shown in FIG. 6, an optical member in which an antireflection film is formed on the surface of the substrate 4 by a plurality of transfer processes and a method for manufacturing the optical member will be described in detail. .

First, a single transfer process that is the basis of a plurality of transfer processes will be described with reference to FIGS.
FIG. 1 is a schematic diagram of a manufacturing apparatus according to Embodiment 1 of the present invention. 2A and 2B are schematic views of the mold. FIG. 3 is an explanatory diagram of the single transfer process of the mold. 4 (a) and 4 (b) are illustrations of a single transfer area.

This manufacturing apparatus is configured as shown in FIG.
A substrate 4 on which an antireflection film is to be formed is set on the upper surface of the stage 6. A head 1 is provided above the stage 6 so as to face the upper surface of the stage 6. The head 1 formed of a member that transmits light with high efficiency, such as glass or quartz, is attached so as to be driven up and down so as to approach and separate from the upper surface of the stage 6. An ultraviolet irradiation unit 2 is attached to the top of the head 1. A mold 3 as a microstructured mold having a microstructure on the surface is attached to the lower portion of the head 1 using a fixing jig (not shown). The mold 3 is made of a member that transmits light with high efficiency, such as glass or quartz, and can transmit ultraviolet rays irradiated from above to the lower side of the mold 3. Further, a fine structure pattern 31 is formed on the lower surface of the mold 3 as shown in FIGS. 2A and 2B by using electron beam drawing and dry etching. Between the upper surface of the mold 3 and the lower surface of the head 1, as shown in FIG. 2 (b), an L-shaped plate-shaped light shielding body 32 is formed. The light shielding body 32 is formed by forming a metal layer such as chromium using vapor deposition or sputtering, printing a black body paint, or pasting the black body sheet via an adhesive sheet (not shown). The upper surface of the mold 3 is partially covered, and the amount of ultraviolet light passing through is limited only in the arranged region.

Further, the mold 3 is subjected to fluorine-based mold release treatment after being cleaned by various methods such as plasma cleaning before being attached to the head 1.
The substrate 4 is a thin plate made of a material such as glass, SUS, or PET film, and a reactive curable resin 5 is disposed on the upper surface of the substrate 4 by coating or printing. The surface of the substrate 4 is subjected to a coupling process for improving the adhesion with the reactive curable resin 5. The reactive curable resin 5 is arranged in a liquid state before curing.

  The head 1 can be driven by a control controller (not shown) with a feed accuracy of 1 μm or less in each of three orthogonal X-axis / Y-axis / Z-axis X / Y / Z directions. The press pressure at the time of transfer to the reactive curable resin 5 can be monitored using a load cell (not shown).

  The fine structure pattern 31 is formed with a width of DX31 in the X direction centering on the center line L1 shown in FIG. 2 and a width of DY31 in the Y direction centering on the center line L2. The order of the fine structure pattern 31 is micro and nano order, and there are various structures such as a dot pattern and a line pattern.

  The light shielding body 32 arranged so as to cover a part of the fine structure pattern 31 in a plan view of FIG. 2B is separated by a distance DX32 in the X direction from the center line L1 and a distance DY32 in the Y direction from the center line L2. From the position to the outer shape of the mold 3 in each direction, the L-shaped area is arranged to be shielded from light. As specific numerical examples, the outer shape of the mold 3 is about 30 mm square, the width DX31 in the X direction of the microstructure pattern 31 is 20 mm, the width DY31 in the Y direction is 20 mm, the distance DX32 in the X direction is 5 mm, and the distance DY32 in the Y direction. Was 5 mm.

  FIG. 3A shows the flow during transfer of the liquid reactive curable resin 5 disposed on the substrate 4. As shown in FIG. 3A, the liquid reactive curable resin 5 dropped on the substrate 4 on the opposite position of the mold 3 is laterally applied by the press pressure P1 from the time when the lowered mold 3 comes into contact. It is pushed out to reach a predetermined outer shape with a constant volume. Specifically, the reactive curable resin 5 spreads in a generally circular shape.

  Thereafter, as shown in FIG. 3B, the reactive curable resin 5 is cured by irradiating the ultraviolet rays 21 from the upper part of the mold 3. In this case, in the region where the light shielding body 32 is disposed. The amount of light passing through is limited.

  Immediately below the region where the light shield 32 is not disposed, a cured resin region 51 is formed in which the reactive cured resin 5 has reacted and cured. Immediately below the region where the light shielding body 32 is disposed, the reactive cured resin 5 does not react completely and an uncured uncured resin region 52 is formed.

  4 (a) is a side view of the state shown in FIG. 2 (b), which shows a region where 32P is a light shielding body 32 and the amount of light passing through is restricted and a region where ultraviolet rays pass without being restricted by the light shielding body 32. The boundary position is shown. FIG. 4B is an enlarged plan view showing the reactive curable resin 5 in the region 32P on the substrate 4 transferred by the above reaction process from the upper surface. The reactive cured resin 5 pressed down by the mold 3 spreads in a generally circular shape, and the cured resin region 51 and the uncured resin region 52 in the region where the light shielding body 32 is disposed have an L-shaped boundary. Is done.

  Up to this point, a single transfer process has been described, but hereinafter, an optical member in which a fine uneven pattern having a larger area than that of a single transfer process is formed by repeating this single transfer process, and its manufacture. The apparatus will be described.

(Example)
FIG. 5 shows a multiple transfer process in which the reaction process described in FIG. 3 is repeated. For convenience, the illustration of the fine structure pattern formed on the lower side of the mold 3 is omitted.

  Steps S1 to S4 in FIG. 5 show the state of transfer in single transfer. Steps S5 to S9 in FIG. 5 are performed when the transfer of the next step is performed on the adjacent portion of the pattern of the uncured resin region 52 transferred in Step S4, and similarly, the light shielding body 32 is used for ultraviolet irradiation. The state of transcription is shown.

Steps S1 to S9 will be described in detail.
Step S <b> 1 in FIG. 5 is a first application process, in which the reactive curable resin 5 is applied on the substrate 4.

  Step S2 in FIG. 5 is a first contact process, in which the mold 3 descends and presses the reactive curable resin 5. Alternatively, the reactive curing resin 5 can be pressed between the mold 3 and the substrate 4 by placing the stage 6 close to the mold 3, and the substrate 4 and the mold 3 are moved relative to each other and pressed.

  Step S3 in FIG. 5 is a first curing process, and the reactive curable resin 5 is irradiated with ultraviolet rays through the mold 3 stopped at the lowering position. By irradiation with this ultraviolet ray, the reactive curable resin 5 on the substrate 4 is in close contact with the fine structure pattern corresponding to the position corresponding to the first region E1 where the light shielding body 32 of the mold 3 is not disposed. The cured resin region 51 is formed by curing, and the uncured resin region 52 that is not cured is formed in the reactive cured resin 5 corresponding to the position corresponding to the second region E2 in which the light shielding body 32 is disposed.

Step S4 in FIG. 5 is a first release process, in which the mold 3 is raised and released.
Next, step S5 in FIG. 5 is a second coating process, and a liquid reactive cured resin 53 is newly applied by coating next to the cured resin region 51 and the uncured resin region 52 that have already been transferred onto the substrate 4. Placed in.

  Step S6 in FIG. 5 is a transfer position changing step, and the mold 3 is moved to the next transfer position so that a part of the mold 3 overlaps the cured resin region 51 transferred in step S4. Alternatively, the substrate 4 and the mold 3 may be moved relative to each other.

  Here, the reactive curable resin 53 is applied to the substrate 4 in step S5 and then the mold 3 is moved to the next transfer position in step S6. However, after the mold 3 is moved to the next transfer position, The same applies when the reactive curable resin 53 is applied to the substrate 4.

  Step S7 in FIG. 5 is a second adhesion process. Like step S2, the reactive cured resin 53 is expanded by the lowering of the mold 3, but the expanded reactive cured resin 53 is adjacent to the adjacent portion. The resin that is stationary in the uncured resin region 52 is mixed at the boundary 5A, and the flow velocity is reduced. The reactive curable resin 53 whose speed has been relaxed does not reach the boundary 5B with the region 51 where the cured resin exists. That is, since the flow velocity becomes zero between the boundary 5A and the boundary 5B, the boundary portion between the reactive curable resin 5 that has already been transferred and the reactive curable resin 53 that is transferred next is stably filled, and the flat transfer It becomes a surface.

  Step S8 in FIG. 5 is the second curing process, and the ultraviolet light 21 is irradiated using the light shielding body 32 as in step S3. A state in which the reactive curable resin 5 on the substrate 4 is in close contact with the fine structure pattern corresponding to the position corresponding to the third region E3 where the light shielding body 32 of the mold 3 is not disposed by the irradiation of the ultraviolet ray 21. Is cured to form a cured resin region 51, and the reactive cured resin 5 corresponding to the position corresponding to the fourth region E4 where the light shielding body 32 is disposed forms an uncured resin region 52 that is not cured. . That is, in the state where the portion that was the uncured resin region 52 in step S4 and the reactive cured resin 53 that has just been transferred are limited to the same thickness as the cured resin region 51 in the mold 3 and the substrate 4, the ultraviolet light is transferred. The cured resin region 51 is cured by irradiation.

In step S9 in FIG. 5, a mold release process is performed in the same manner as in step S4.
5 is repeated in the X-axis direction of the substrate 4 and in the Y-axis direction, thereby repeating the fine structure pattern on a wide range of the substrate 4 as shown in FIG. Can be manufactured. In FIG. 6, a total of 36 transfers are performed, 6 times in the X direction and 6 times in the Y direction. The lower left of the drawing is the first single transfer region T1, and the upper right of the drawing is the 36th. This is a single transfer region T36. In each of the single transfer regions T1, T2,..., T36, there are a cured resin region 51 and an uncured resin region 52. However, the uncured resin region 52 at each boundary portion disappears by a plurality of transfers, and the entire transfer region The uncured regions exist only in the single transfer regions T6, T12, T18, T24, T30, and T36 on the right side of this, and the single transfer regions T31 to T32 on the upper side. For the sake of convenience, each boundary portion is divided and displayed with a solid line, but there is no visually discontinuous pattern portion in the solid line portion, and a surface without pattern collapse is formed over the entire surface.

The reason why a plurality of transfer processes for large-area transfer in this embodiment and the boundary portions of a plurality of transfer areas are formed with high accuracy will be compared with the comparative example shown in FIG.
(Comparative example)
Steps S1 to S3 in FIG. 7 show the state of transfer in single transfer. Steps S4 to S6 in FIG. 7 show the state of transfer when the transfer of the next step is performed at the adjacent portion of the pattern transferred by the above process.

In step S <b> 1 of FIG. 7, the reactive curable resin 5 is applied on the substrate 4.
In step S <b> 2 of FIG. 7, the mold 3 is lowered to spread the reactive curable resin 5. And it hardens | cures by ultraviolet irradiation. At that time, the reactive curable resin 5 is completely cured over the entire area that has been spread out, and the whole becomes the cured resin region 51.

In step S3 of FIG. 7, the mold 3 is raised.
In step S4 in FIG. 7, the mold 3 is moved so as to overlap the cured resin region 51 transferred in the previous step, and a liquid reactive cured resin 53 is newly added to the adjacent portion of the already transferred cured resin region 51. Are arranged by application.

  In step S5 of FIG. 7, the reactive cured resin 53 is pushed and expanded by the lowering of the mold 3, but the spread reactive cured resin 53 is predetermined up to the cured resin region 51 that has already been transferred and cured. When the flow-in boundary position is raised at a flow velocity, a step d is generated at the portion where the boarding is performed.

In step S6 of FIG. 7, the mold 3 is raised and released.
In order to avoid climbing, it is necessary to apply the reactive curable resin 53 in step S4 of FIG. 7 at a position sufficiently away from the cured resin region 51 cured in the previous step. The resin does not reach the cured resin region 51, and voids, that is, transfer omission occurs. The climbing of the resin or missing transfer is visually recognized as a discontinuous portion, resulting in a serious quality defect.

  As can be seen by comparing this comparative example with the example of the present invention, in the case of the example of the present invention, the uncured resin region 52 works well as described in FIG. In order to suppress filling and to ensure filling properties, a flat and visually continuous pattern surface can be formed.

  As described above, the light path on the upper surface of the mold is intentionally controlled to form the uncured portion by controlling the optical path of the ultraviolet rays. A stable formation of a fine structure is possible. Also, producing a large area fine structure from a small area mold not only reduces the initial cost of the mold, but also helps to obtain a large variety of large area fine structures.

(Embodiment 2)
FIG. 8 shows a second embodiment of the present invention.
In the manufacturing apparatus of the first embodiment, the light shielding body 32 is disposed between the head 1 and the mold 3, but in the second embodiment, the position of the light shielding body 32 is different from that of the first embodiment.

Note that the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and a part of the description is omitted.
In FIG. 8, the stage 6 is configured by a member that transmits light with high efficiency, such as glass or quartz, and the ultraviolet irradiation unit 2 is disposed below the stage 6. A light shield 54 is formed on the lower surface of the stage 6. The light-shielding body 54 is formed by forming a metal layer such as chromium by vapor deposition or sputtering, printing a black body paint, or pasting the black body sheet via an adhesive sheet (not shown). The stage 6 is arranged so as to partially cover it, and the ultraviolet ray transmission is limited only in the arranged area.

  As a result, the mold 3 does not need to be selected from a light transmitting member such as glass or quartz as described in the first embodiment. For example, the mold 3 can be selected from an inexpensive metal mold such as Ni or Si mold. Can be enlarged.

  In each of the above embodiments, the ultraviolet irradiation unit 2 is provided on the head 1, and the light shielding body 32 is disposed on the lower surface of the head 1, or the ultraviolet irradiation unit 2 is provided below the stage 6. Although the case where the light-shielding body 54 is disposed between the ultraviolet irradiation units 2 has been described, the manufacturing apparatus and the manufacturing method for controlling the optical path of the ultraviolet rays to form the uncured portion are not limited to this.

  In each of the above embodiments, the reactive curable resins 51 and 53 are ultraviolet curable resins, and these resins are cured by irradiation with ultraviolet rays generated from the ultraviolet irradiation unit 2. 51 and 53 are thermosetting resins that are cured by thermal energy, and an infrared irradiation unit is provided in place of the ultraviolet irradiation unit 2, or the reactive curable resins 51 and 53 are electron curable resins that are cured by electronic energy, and ultraviolet rays are used. Instead of the irradiation unit 2, an electron irradiation unit may be provided and configured.

  Further, in each of the above embodiments, the reactive curable resins 51 and 53 are ultraviolet curable resins, and the resin is irradiated with the light amount partially limited by the shield 32. Instead of irradiating with the light amount limited, the ultraviolet irradiation unit 2 can be scanned and drawn so as to irradiate only the portion to be cured and cured. Further, when the reactive curable resins 51 and 53 are made of an electron curable resin that is cured by electron energy, the electron energy is irradiated only to a portion to be cured without using a shielding body that limits the amount of electrons. It can also be scanned and drawn to be cured.

  INDUSTRIAL APPLICABILITY The present invention can contribute to quality improvement and cost reduction of an optical member having an infinite number of uneven structures on the surface.

DESCRIPTION OF SYMBOLS 1 Head 2 Ultraviolet irradiation unit 3 Mold 4 Board | substrate 5,53 Liquid reactive cured resin 21 Ultraviolet 31 Microstructure pattern 32,54 Light-shielding body 51 Resin cured area 52 Uncured resin area E1 1st area E2 2nd area E3 1st Region 3 E4 Fourth region DX31 Width in the X direction of the fine structure pattern 31 DY31 Width in the Y direction of the fine structure pattern 31 DX32 Distance in the X direction from the center line of the formation position of the light shield 32 DY32 Formation of the light shield 32 Distance in the Y direction from the center line of the position

Claims (5)

An optical member having a continuous microstructure, repeatedly transferring a microstructure mold having a microstructure on the surface to a reactive curable resin disposed on a substrate,
A first application step of applying a reactive curable resin on the substrate;
A first adhesion step of bringing the reactive curable resin into close contact with the surface of the microstructure mold by bringing the substrate and the microstructure mold close together;
The reactive curable resin corresponding to the first region of the microstructured mold in the first adhesion step is cured, and the reactive curable resin corresponding to the second region of the microstructured mold is uncured. A first curing step that remains in the state;
A first release step of releasing the microstructure mold from the cured and uncured resin;
A second application step of applying a reactive curable resin on the substrate adjacent to the uncured resin corresponding to the second region;
A transfer position changing step of moving the transfer position so that a part of the microstructure mold overlaps the cured resin in the first curing step;
The substrate and the microstructure mold so that the reactive curing resin applied in the second coating step is sandwiched between the substrate and the microstructure mold and the reactive cure resin is brought into close contact with the surface of the microstructure mold. A second contact step of relatively moving
The reactive curable resin corresponding to the third region of the microstructured mold in the second adhesion step is cured, and the reactive curable resin corresponding to the fourth region of the microstructured mold is uncured. A second curing step that remains in the state;
A second mold release step of releasing the microstructured mold from the cured and uncured resin,
Manufacturing method of optical member.   The method for manufacturing an optical member according to claim 1, wherein the second coating step, the transfer position changing step, the second adhesion step, the second curing step, and the second release step are repeated. The second curing step includes
In the first curing step, the transfer is performed so that the third region to be transferred is overlapped with the first region which has already been transferred.
The manufacturing method of the optical member of Claim 2. A part of the outer periphery of the fine structure transfer region transferred in the first curing step and the second curing step is the second region and the fourth region, and the remaining outer periphery and the inside thereof are the first region. A region and a third region,
The manufacturing method of the optical member of Claim 2 or 3. The reactive curable resin is an ultraviolet curable resin,
The manufacturing method of the optical member in any one of Claim 1 to 4.

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