KR100280312B1 - Kenoform device manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fabricating a kinoform element, wherein a mask (1) for coating a metal film is manufactured from designed multistep KE data (a), and applied to a patine of the mask (1) for manufacturing a metal film coating. Then, the metal film 2 is coated on the substrate 4 (b), and a plurality of lithographic masks 10, 20, ... are fabricated by the number of profiles from the designed KE data (c), and the photoresist 3 is formed. Coating on the substrate 4 (d), exposing (e), removing the exposed photoresist 3 according to the patine of the lithographic mask 10 (f), and removing the photoresist 3 (G), the photoresist 3 coated on the substrate 4 is removed (h), and the steps (c) to (h) are repeated (i), and the shape of KE is When the metal film 2 is completed, the metal film coating mask of the multi-step KE is produced by removing the metal film 2, and the metal film coating mask is used to form the boundary surface of the zone. By manufacturing a KE by performing a multi-step manufacturing process by coating a metal film, the KE can be manufactured with clean processing between zones and zones so that the diffraction efficiency does not fall below the theoretical value. It works.

Description

Kenoform device manufacturing method

TECHNICAL FIELD This invention relates to a method for fabricating a kinoform element, and prior to inputting a kinoform element (KE) (hereinafter referred to as KE) used in a holographic optical element applied optical system to a machining process. The present invention relates to a method for fabricating a kinoform device that can obtain a multistep KE shape close to perfection by coating a metal film between a zone and a zone on an expected glass substrate.

The prior art will be described with reference to the attached FIGS. 1 to 4.

In general, KE is the first (b) attached to the optical element having a stylized refractive power, as shown in the attached first (a), that is, a lens having a thickness thinner than the center of the left and right, and having a flat surface opposite the curvature plane (b). As shown in Fig. 1, the left and right curvature surfaces have three jagged zones (z), and the height from the flat surface of the central axis is made in the shape of a kinoform Fresnel zone plate with the same height as the jagged height, and then the light diffraction The effect is to use the same role as the existing lens.

However, the above-described kenoform Freel zone plate shape is only ideal, and since the spacing of the respective zones is minute, the ideal kenoform Fresnel zone such as the attached second (a) can not be manufactured.

Therefore, in order to manufacture the shapes of the zones closer to the sawtooth in the related art, as shown in the attached second (b) is manufactured stepwise, the manufacturing process with reference to the accompanying Figure 4 is as follows.

A first step (a) of making a lithographic mask (10) from the designed KE data, a second step (b) of coating a photoresister on the surface of the lens to be processed, and a mask for exposure A third step (c) of placing the photoresist on the surface, a fourth step (d) of removing the photoresist of the exposed area after exposure, and five etching of the exposed area using ion bombardment equipment. The first step (e), the sixth step (f) of removing the residual photoresist, and the seventh step (g) of repeating the first to sixth steps for multistep.

Since the manufacturing of the lithography mask of the first step is to produce the stairs of the zone one by one, there must be a profile (profile) as many as the number of stairs to have the corresponding lithography mask necessary for the production of the stairs.

The conventional KE manufacturing method as described above is shown in FIG. 4, in the mask of FIG. 4, (a) is the lens portion at the center side, (b) is the first zone, and (c) is the second zone. , (d) is the part where the stairs are to be formed in the third zone.

The multi KE produced through such a step has a shape as shown in FIG.

However, FIG. 3, which is the shape of the multi KE produced by the above process, is different from the shape shown in FIG. 2 (b).

More specifically, in FIG. 2 (b), the height h1 and the intervals of the stairs are the same, the height hm of the zone is the same, and the zone is clean between the zones.

However, the zone of FIG. 3 has been processed without any significant problems in the height and spacing of the steps, but the zone is very messy.

The reason why Kinoform Fresnel Zone manufactured through the above manufacturing process is different from the zone of multistep KE for the first purpose is that after manufacturing the first step to maintain high diffraction efficiency when manufacturing multistep KE, For the processing of the second step, it is necessary to exactly match the pattern of the mask and the pattern already formed in the lens, since the actual matching of the pattern of the mask with the patine already formed in the lens is impossible.

For the above reason, the conventional multi-KE has a diffraction efficiency that is significantly lower than the theoretical value because the zone between the zone and the zone having different distances between the stairs and the stairs is dirty.

However, although the exposure equipment that requires high precision can be used to prevent the diffraction efficiency from falling to the theoretical value, the manufacturing cost is high, and no matter how high-precision exposure equipment is used, it is practically practical to clean the patine shape between the zone and the zone effectively. There is an impossible problem.

Accordingly, the present invention is to solve the conventional problems, before the KE processing, after coating the metal film at the boundary position of the zone and the zone to be formed on the lens surface and performing the existing processing process, the coating after the processing process is completed Provided is a method for fabricating a kinoform device for removing multi-step metal to form a multistep KE shape.

1 (a) is a cross-sectional view of a general lens,

Figure 1 (b) is a cross-sectional view of the lens manufactured in the shape of an ideal kinoform fresnel zone plate.

2 (a) is a shape diagram showing a part of the first (b) diagram,

FIG. 2 (b) is a shape diagram for realizing FIG. 1 (a).

3 is a shape diagram in which FIG. 2 (b) is actualized.

4 is a process diagram of a method for manufacturing a kinoform device according to a conventional embodiment.

5 (a) and 5 (b) are process diagrams of a method for manufacturing a kinoform device according to an embodiment of the present invention.

FIG. 6 is an enlarged view of the zone of the actual kenoform element manufactured according to FIG.

The structure of the present invention as a means for achieving the above technical problem comprises a first step of manufacturing a metal film coating mask from the designed KE data; A second step of coating a metal film on the boundary between the zone to be formed on the surface of the lens to be processed; A third step of manufacturing a lithographic mask from the designed KE data; Coating a photoresist on the surface of the lens to be processed; A fifth step of exposing the lithographic mask by placing the mask on the surface of the photoresist; A sixth step of removing the photoresist of the exposed portion; A seventh step of etching the exposed portion using an ion bombardment device; An eighth step of removing the residual photoresist; A ninth step of repeating the processes from the third step to the eighth step for the multistep; And a tenth step of removing the metal coating layer.

With the above-described configuration, a person having ordinary skill in the art to which the present invention pertains will be described in detail with reference to the accompanying drawings.

5 (a) and 5 (b) are process diagrams of a method for manufacturing a kinoform device according to an embodiment of the present invention.

As shown in FIG. 5, the process for manufacturing a kinoform device of the present invention is to fabricate a metal film coating mask 1 from the designed multistep KE data (a), and to manufacture the metal film coating. The metal film 2 is coated on the substrate 4 according to the pattern of the mask 1 (b), and a plurality of lithographic masks 10, 20,... Are prepared by the number of profiles from the designed KE data (c). Coating the photoresist 3 on the substrate 4 (d), exposing (e), removing the exposed photoresist 3 according to the pattern of the lithographic mask 10 (f), and The portion where the photoresist 3 is removed is etched (g), the photoresist 3 coated on the substrate 4 is removed (h), and the steps (c) to (h) are repeated (i). When the shape of KE is completed. The metal film 2 is removed (j).

FIG. 6 is an enlarged view of the zone of the actual kino pain element produced according to FIG.

A method of fabricating a kinoform device according to an embodiment of the present invention with reference to FIGS. 5 and 6 will be described.

The producer decides in what form the KE is to be made, that is, the height of each zone of the KE to be manufactured, and the length of each zone.

When the shape of the KE is determined as described above, since it is impossible to produce the same shape as the shape of the KE determined as mentioned in the prior art, the number of steps and the height of the stairs to be processed according to the height and length of each zone, the width of the stairs Create data for ie KE data to be designed.

Then, the metal film coating mask 1 is fabricated on the basis of the KE data, and the metal film coating mask 1 is shown in FIG. 5 (a).

Then, the metal film coating mask 1 will have a pattern coinciding with the position of the stairs bounding each zone as shown in FIG.

The manufacturer places the metal film 3 on the substrate 4 in accordance with the pattern formed on the lens surface, i.e., the substrate 4, on the substrate 4 to be processed. Coating is performed as shown in (b) of FIG. 5 (a).

The metal film 2 coated as described above is shown in FIG. 6, and the width of the metal film 3 is equal to the width of one stairway in the final process step.

After coating the metal film 2, the manufacturer manufactures the lithographic mask 10 as shown in FIG. 6C based on the KE data.

The KE data has as many profiles as the number of steps to be produced, and since the steps are manufactured according to the profile, the lithography mask 10 should be manufactured as many as the number of steps.

After the lithography mask 10 was produced. The manufacturer coats the photoresist 3 on the surface of the substrate 4 to be processed as shown in (d) of FIG. 5 (a).

The substrate is a glass lens material.

After the coating of the photoresist 3 is finished, the manufacturer arranges the lithographic printing mask 10 and places it on the photoresist 3 coated substrate 4, as shown in (e) of FIG. 5 (a). Exposure is performed.

The light transmitted through the pattern formed in the lithographic mask during exposure (e) changes the properties of the photoresist 3 on the exposed substrate 4.

The photoresist 3 whose properties have been changed as described above is removed by the developer, and the photoresist 3 removed by the developer is the same as (f) in FIG. 5 (a).

The manufacturer places the ion bombardment device on the portion where the photoresist 3 has been removed, and etches the ion bombardment device by ejecting ions from the ion bombardment device for a corresponding time according to the designed data.

In the above etching process, the ejected ions have a significantly lower etching rate with respect to the metal film 2 than the glass, which is a material of the substrate 4, so that the substrate 4 bounded by the metal film 3 is not etched. Do not.

The state of ion etching as described above is well shown in (g) of FIG. 5 (a).

After etching, the manufacturer removes the remaining photoresist 3 as shown in FIG. 5 (b) (h).

One of the steps to be formed in each zone is produced by the steps (a) to (h) in FIG. 5 (a) and FIG. 5 (b) as described above.

Therefore, in order to achieve the shape of the KE designed by the manufacturer, the steps (a) to (h), that is, the steps as shown in (i) of FIG. 5 (b) to be attached, must be repeated by the number of steps to be formed.

Thus, the manufacturer aligns the second lithographic mask 2 fabricated to produce the next step on the photoresist 3 coated substrate.

In the above, the second lithographic mask 20 is not aligned at the position intended by the manufacturer, ie, in accordance with the designed data, due to the mechanical microscopic alignment error even when the manufacturer attempts to align the position at the intended position.

When the exposure process is performed in a state where an alignment error occurs as described above, the light exposure portion of the photoresist 3 coated on the substrate 4 becomes narrower or wider than the width of the step which has already been manufactured with a very small difference.

The light exposed portion of the photoresist 3 is narrower or wider than the width of the already prepared stairs. After removing the photo exposed photoresist 3 and etching as an ion bombardment device, the portion to be etched is initially produced. This means that it will be different from the width of the stairs.

Although the width of the etched stairs is different from the width of the fabricated stairs, it does not mean that the KE does not differ greatly from the intended one, but the difference from the initial etching due to the mask alignment error at the boundary of the zone is attached. Since it becomes an uneven shape like (h) of FIG. 3, it produces a big difference of diffraction efficiency different from what is desired.

However, even when alignment errors of the lithographic masks 20, 30, ... occur, the glass, which is the material of the substrate 4 on the interface of the metal film 3, is ions by the metal film 2 coated on the interface of the zone. It is not etched by ions emitted from impact equipment.

The above reason is that the etching rate due to the ions of the metal film 3 is significantly lowered, so that the glass under the metal film 3 is not etched.

Therefore, the interface of the zone is cleanly etched as shown in (h2) of FIG.

After the etching process, the manufacturer removes the remaining photoresist (3).

Then, the process (i) is repeated by the number of steps to be manufactured so as to obtain the shape of the KE initially determined.

When the final KE shape is produced, the metal film 2 coated on the substrate 4 is removed as shown in FIG. 5 (b) attached with a chemical agent.

The present invention is to manufacture a multi-step KE metal film coating mask, and to coat the metal film on the interface of the zone using the metal film coating mask to perform a multi-step manufacturing process to manufacture the KE, the processing between the zone and the zone cleanly As a result, the KE may be manufactured in which the diffraction efficiency does not fall below a theoretical value, thereby lowering a defective rate and increasing quality.

Claims (2)

In the method of manufacturing a kinoform element having a plurality of zones, a metal film coating mask having a form that allows the coating of the boundary between the zone and the zone of the kenoform element with a metal film to produce a predetermined surface of the lens surface A first step of coating a metal film on the site; A second step of coating a photoresist on the lens surface by using a lithographic mask; Placing the mask for lithography on the surface of the photoresist and exposing the photoresist to remove the photoresist in the portion; Etching the exposed portion and removing residual photoresist; A method of manufacturing a kinoform device comprising a fifth step of removing the metal coating film. The method of claim 1, wherein the first to fourth steps are repeated as many steps as the steps to be formed in order to manufacture the multi-step according to the data of the designed kenoform device.

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