JP3957771B2 - Optical device manufacturing method - Google Patents

Description

[0001]
[Industrial application fields]
This inventionOptical device manufacturing methodAbout.
[0002]
[Prior art]
Optical devices such as lenses that are manufactured by various physical and chemical methods instead of using conventional polishing methods have been proposed and put into practical use.
For example, a photoresist layer is provided on a transparent glass substrate, and a circular or elliptical shape is patterned by photolithography, and the patterned photoresist layer is heated to a temperature higher than the glass transition point. After the surface of the photoresist is formed into a convex spherical shape by the action of surface tension, the photoresist and the transparent substrate are etched, and the convex spherical shape due to the photoresist surface is engraved on the transparent substrate, It has been proposed to form a “convex spherical refracting surface” as the surface shape of the transparent substrate itself (Japanese Patent Laid-Open No. 5-173003).
The optical device manufactured by such a method can be used as, for example, a microlens or a microlens array.
[0003]
In such an optical device manufacturing method, since the convex spherical shape formed on the photoresist is due to the thermal flow and surface tension of the photoresist, the formed spherical shape is good, but the curvature radius of the spherical surface is controlled. Not always easy. For this reason, when trying to obtain a highly accurate optical device as designed, it has been difficult to improve the yield of optical device manufacturing. This tendency is particularly remarkable when a convex spherical surface having a large curvature radius is formed.
[0004]
Further, since the convex shape formed on the photoresist depends on thermal flow and surface tension, it is not easy to form shapes other than the spherical shape. For this reason, it is difficult to manufacture an optical device having an aspherical shape.
[0005]
[Problems to be solved by the invention]
  The present invention has been made in view of the above-described circumstances, and is a novel high-precision for the radius of curvature.Of an optical device manufacturing methodFor the purpose of provision.
[0006]
  Another object of the present invention is a novel optical device having an aspheric shapeHow to manufactureOn offeris there.
[0009]
  When molding is performed using the optical device as a mold, an optical device having a desired concave curved surface shape can be efficiently manufactured.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a thermoplastic material layer is formed in a predetermined thickness on a flat surface of a device material, the thermoplastic material layer is patterned into a relief shape according to one or more device patterns, and then patterned. The formed thermoplastic material layer is heat-treated, and the surface shape of the thermoplastic material is changed to a convex curved surface shape for each device pattern by the heat flow and surface tension of the thermoplastic material. A method of manufacturing an optical device having one or more convex curved surfaces having a desired curvature on the surface of a device material by performing ECR etching and engraving one or more convex curved surfaces of the thermoplastic material on the device material. It is characterized by the following points.
That is, the selection ratio of ECR etching is adjusted and set according to the magnitude relationship between the curvature of the convex curved surface shape of the surface of the thermoplastic material and the curvature of the convex curved surface to be formed on the surface of the device material.
[0011]
In the optical device manufacturing method according to claim 1, “the curvature of the convex curved surface shape of the thermoplastic material surface is set larger than the curvature of the convex curved surface to be formed on the device surface, and the selection ratio of ECR etching is adjusted to be small. Can be set ”(Claim 2).
[0012]
According to a third aspect of the present invention, a thermoplastic material layer is formed in a predetermined thickness on a flat surface of a device material, and the thermoplastic material layer is patterned into a relief shape according to one or more device patterns, and then patterned. The thermoplastic material layer is heat-treated, and the surface shape of the thermoplastic material is changed to a convex curved shape with a predetermined curvature for each device pattern by the thermal flow and surface tension of the thermoplastic material. On the other hand, an optical device having one or more desired convex aspheric surfaces on the surface of the device material is manufactured by performing ECR etching to engrave one or more convex curved surfaces of the thermoplastic material on the device material. The method is characterized by the following points.
That is, the selection ratio of ECR etching is changed over time according to the shape relationship between the convex curved surface shape of the surface of the thermoplastic material and the convex aspheric surface to be formed on the surface of the device material.
[0013]
The “device pattern” is a pattern corresponding to one of the convex curved surfaces (including convex aspherical surfaces) formed in the device material. When there are two or more convex curved surfaces formed in the device material, the device pattern The number will be 2 or more. In this case, the two or more device patterns may have the same shape or different shapes. The device pattern can be circular, elliptical, rectangular or polygonal.
[0014]
“Heat treatment” refers to a process in which a thermoplastic material is heated and the surface of the thermoplastic material is deformed into a convex curve shape by the action of thermal flow and surface tension of the thermoplastic material.
The “thermoplastic material” can be used without particular limitation as long as it can perform the above heat treatment and can be subjected to ECR etching after the heat treatment. For example, various “resists” can be suitably used. As in the invention described in claim 5, it is also possible to use a photoresist as the thermoplastic material.
[0015]
Preferable specific examples of the thermoplastic material include metal relates such as polyvinyl chloride, polystyrene, polyurethane, and polyglycidyl methacrylate resin.
[0016]
“Engrave the surface shape of the thermoplastic material on the device material” means to form a convex curved surface shape corresponding to the surface shape of the thermoplastic material and a convex curved surface shape corresponding to 1: 1 on the device material by ECR etching. Say.
[0017]
“Selection ratio” is defined as “β / α” when the etching rate for a thermoplastic material is “α” and the etching rate for a device material is “β” in ECR etching for a thermoplastic material and a device material. Is a dimensionless quantity to be played.
[0018]
  This “adjustment / setting or change over time” of the selection ratio depends on the type of gas introduced, the amount of gas introduced, and the high frequency for plasma generation.And / orAdjustment or setting of one or more of microwave power, device material temperature, and pressure, or changes with time can be performed. “Change over time” includes step changes and continuous changes.
[0019]
  The optical device manufacturing method according to claim 1, wherein “a thermoplastic material layer formed in a predetermined thickness on a flat surface of a device material is patterned into a relief shape according to one or more device patterns”. This is done as follows.
  That is, “an intermediate layer and a thin photoresist layer are laminated on a thermoplastic material layer, and the thin photoresist layer is patterned according to one or more device patterns by photolithography, and the patterned photoresist layer is masked. As for the middle layerFirst dry etchingAnd copy the photoresist pattern to the intermediate layer, and use the intermediate layer pattern as a mask for the thermoplastic material layer.SecondDry etchingDo.Use the intermediate layer pattern as a maskSecondIn dry etching, the intermediate layerOn the maskThe thin photoresist layer is also removed.
  Subsequently, a third dry etching for removing the intermediate layer is performed to remove the intermediate layer, leaving only the thermoplastic material patterned in a relief shape on the surface of the device material.
  For patterning by photolithography, light may be uniformly irradiated using a mask, or a pattern may be drawn by “laser drawing”.
[0020]
The “intermediate layer” may be formed by vacuum deposition or sputtering of a metal material such as copper or aluminum, or may be formed by vacuum deposition, reactive deposition or sputtering of a non-metallic material such as Si. The thickness of the intermediate layer made of a metal material is preferably 2000 to 10,000 mm, and the thickness of the intermediate layer made of a non-metal material is preferably 2000 to 5000 mm.
[0021]
Etching of the intermediate layer can be performed by “wet etching” in the case of an intermediate layer made of a metal material, and “dry etching” in the case of an intermediate layer made of a non-metallic material.
[0022]
  An “optical device” is manufactured by the manufacturing method according to claim 1, 2, 3, or 4. Of this optical device,A reflective film can be formed on a surface on which one or more convex curved surfaces or convex aspheric surfaces are formed.
[0023]
  Furthermore, manufactured by the above methodUsing the optical device as a mold, the optical device can be manufactured by molding, and the optical device manufactured by this method has one or more desired concave curved surfaces.
[0024]
[Action]
In FIG. 1A, reference numeral 1 denotes a device material, and reference numeral 2 denotes a patterned thermoplastic material layer. The “device pattern” is a pattern in which the shape of the thermoplastic material layer 2 in (a) is viewed from the upper side of the figure. The patterned thermoplastic material layer 2 has a “relief” of the device pattern depending on the layer thickness. I am doing. By referring to this state, it is said that the thermoplastic material layer 2 is “patterned into a relief according to the device pattern”.
[0025]
As described above, when the “heat treatment” is performed in a state in which the thermoplastic material layer 2 is patterned in a relief shape, the thermoplastic material is deformed as shown in FIG. It becomes the shape.
[0026]
If the device pattern is circular, the surface shape 2A is a “convex spherical surface”. If the device pattern is elliptical, the surface shape 2A is a spheroidal convex curved surface having a large radius of curvature in the major axis direction and a short radius of curvature in the uniaxial direction. Further, when the device pattern is rectangular or polygonal, it becomes “a convex curved surface having a shape corresponding to the device pattern”.
[0027]
When the device pattern is a non-circular shape such as “oval shape, rectangular shape, polygonal shape”, the radius of curvature of the convex curved shape of the thermoplastic material surface after heat treatment is not uniquely determined. In this case, the “curvature of the convex curved surface” is the maximum or minimum of the curvatures near the top of the surface shape.
[0028]
Subsequently, when the ECR etching is performed on the thermoplastic material after heat treatment and the device material 1 to completely etch the thermoplastic material, as shown in FIG. 1C, the surface shape 2A of the thermoplastic material is obtained. Is engraved as the surface shape 1A of the device material 1.
[0029]
The surface shape 1A engraved on the device material 1 and the surface shape 2A of the thermoplastic material before etching are in a corresponding relationship. If the selection ratio is 1, the surface shapes 1A and 2A are the same shape. However, when the selection ratio is different from 1, the surface shape 1A is different from the surface shape 2A.
[0030]
The case where the device pattern is circular will be described as an example. In this case, the surface shape 2A is a “convex spherical shape”, and the surface shape 1A is also a convex spherical shape. Since the device material 1 is etched faster than the thermoplastic material when the selection ratio> 1, the curvature of the surface shape 1A is larger than the curvature of the surface shape 2A. As in the example of 1 (c), the magnitude relationship of the curvature is reversed.
[0031]
FIG. 2 shows the relationship between the thickness d of the thermoplastic material layer patterned in accordance with the device pattern and the curvature radius R of the convex curved surface formed after the heat treatment. The device pattern is circular, and the convex curved surface is a convex spherical surface. As shown in the figure, the radius of curvature “R” of the “convex spherical surface formed after heat treatment” is small in inverse proportion to the thickness d of the thermoplastic material layer before heat treatment, as indicated by the graph line 2-1. Become. The dots in the figure represent measured values of the radius of curvature: R.
[0032]
When the shape or size of the device pattern changes, the appearance of the “graph line” also changes. However, the qualitative characteristics shown in FIG. 2, that is, the radius of curvature of the convex curved surface formed after the heat treatment, The point of “decreasing in inverse proportion to the thickness of the thermoplastic material layer” remains unchanged.
[0033]
The measured value of the radius of curvature: R, indicated by “dots” in FIG. 2, is distributed between the graph lines 2-1 and 2-3. From this, the following can be understood.
That is, the difference between the graph lines 2-2 and 2-3: ΔR is “the variation in the radius of curvature” of the surface shape formed by the heat treatment, but the variation: ΔR depends on the thickness: d, and “ As “d” decreases, it increases.
[0034]
The reason why the radius of curvature varies as described above is due to errors in the thickness of the thermoplastic material layer: d and subtle differences in heat treatment conditions (heat treatment time, heat treatment temperature, temperature rise rate, substrate temperature distribution, etc.). This inevitably occurs and cannot be removed.
[0035]
When making an optical device by engraving the surface shape identical to the surface shape of the thermoplastic material layer on the device material with a selection ratio of 1 in ECR etching, the “desired radius of curvature” of the convex curve formed in the device material Is large (the curvature is small), it is necessary to increase the curvature radius R of the surface shape of the thermoplastic material after the heat treatment. For this purpose, the thickness of the thermoplastic material layer formed on the surface of the device material is required. The height: d must be reduced, and the variation: ΔR becomes extremely large. Therefore, the probability of obtaining a surface shape having a desired curvature is extremely low, so that the convex curve having the desired radius of curvature is obtained. The yield of the optical device having the above becomes extremely low.
[0036]
In such a case, when the thermoplastic material layer is formed “thick” on the device material and a convex curved surface shape having a large curvature (small curvature radius) is formed by heat treatment, the variation in the curvature radius in that case is small. Therefore, when dry etching is performed on the convex curved surface formed with such a small variation, if the selection ratio is made smaller than 1, the convex curved surface engraved on the device material as described above. The curvature radius of becomes larger than the curvature radius of the convex curved surface shape of the surface of the thermoplastic material.
[0037]
Since the selection ratio in dry etching can be easily controlled precisely, a “convex curved surface having a large radius of curvature” can be accurately formed on a device material by the method described above (claim 2).
[0038]
In general, the selection ratio of ECR etching is adjusted and set according to the magnitude relationship between the curvature of the convex curved surface formed as the surface shape of the thermoplastic material and the curvature of the convex curved surface to be formed on the surface of the device material. According to (Claim 1), a convex curved surface having a desired radius of curvature can be easily formed as a device surface shape.
[0039]
Also, if the selection ratio is changed over time during the ECR etching, the “etching rate ratio” between the thermoplastic material and the device material changes according to the change in the selection ratio. The formed convex curved surface shape can be “deformed” and engraved on the device material, and this can be used to form a convex aspheric surface on the surface of the device material.
[0040]
【Example】
  Specific reference examples and examples will be described below.
Reference example 1
  As a device material, a quartz glass parallel plate (indicated by reference numeral 10 in FIG. 3) of refractive index (wavelength: 1.3 μm for light): 1.452 is prepared, and a thermoplastic material layer 20 is formed on the surface thereof. A photoresist (trade name: OFPR800) was spin coated and then pre-baked to a thickness of 50 μm (changed to 73 μm after post-baking).
[0041]
Using a mask in which black circles having a diameter of 0.8 mm are arranged at a pitch of 1.0 mm (as shown in FIG. 3A, the black circle 31 is formed of a metal thin film on one side of the transparent glass 30). By performing exposure and removing a portion irradiated with light, patterning was performed in a relief shape according to one or more device patterns (circle corresponding to a black circle). FIG. 3B shows a state after patterning (for simplicity, only a portion corresponding to one device pattern is shown).
[0042]
When the patterned thermoplastic material layer is heat-treated and the surface shape of the thermoplastic material 20 is changed to a convex curved surface shape for each device pattern by the heat flow and surface tension of the thermoplastic material, the convexity having a curvature radius of 1.132 mm is obtained. A spherical shape was obtained.
[0043]
In the subsequent ECR etching, when the selection ratio was set to 0.5, convex spherical surfaces having a diameter of 0.8 mm and a curvature radius of 2.210 mm could be formed at a pitch of 1.0 mm on the quartz glass surface. . This convex spherical surface has a focal length of 4.889 mm as a refractive surface.
[0044]
Further, in the same manner as described above, after forming one or more convex curved surfaces in the thermoplastic material, dry etching was performed with an ECR etching selection ratio of 1.25, and the quartz glass surface had a diameter of 0.8 mm. A convex spherical surface having a radius of curvature of 0.885 mm and a focal length of 1.958 mm could be formed at a pitch of 1.0 mm.
[0045]
The dry etching conditions at this time are as follows.
Selective ratio: 1.25 versus introduced gas: O₂1.8 sccM, CHF_Three25.0 sccM, reaction chamber pressure: 3 to 4 × 10^FourTorr, microwave execution power: 620 W, RF execution power: 480 W, etching time: 450 minutes.
The selection ratio is adjusted and set according to the amount of introduced gas. For a selection ratio of 0.5, O₂: 4.2 sccM, CHF_Three: 21.0 SccM.
[0046]
  Example 1
  As a device material, a parallel plate (indicated by reference numeral 10 in FIG. 4) of quartz glass having a refractive index (wavelength: 1.3 μm): 1.452 is prepared, and a thermoplastic material layer 20 is formed on the surface thereof. Polyglycidyl methacrylate resin was applied to a thickness of 50 μm.
[0047]
An Si layer 4 having a thickness of 2000 mm was formed thereon as an intermediate layer, and the photoresist was further spin-coated and prebaked to a thickness of 0.1 μm.
[0048]
Patterning was performed according to one or more device patterns by performing exposure using a mask in which black circles having a diameter of 0.5 mm were arranged at a pitch of 0.6 mm and removing a portion irradiated with light. FIG. 4A shows a state after patterning (for simplicity, only a portion corresponding to one device pattern is shown).
[0049]
  The optical device material after the patterning process is set in an ECR plasma etching apparatus, and CCl_Four11 sccM, He; 5 sccM were introduced, and the pressure in the reaction chamber was 3 to 4 × 10^-FourTorr, microwave execution power: 600W, RF execution power: 500W,First dry etchingFor 5 minutes4B was obtained. Next, the second dry etching is performed under the same conditions as the reference example of the lens array described above to remove the photoresist layer 5 on the Si layer 4 as an intermediate layer, and the Si layer 4 as an intermediate layer as a mask. The state of FIG. 4C was obtained by etching the thermoplastic material layer 20. afterwards,In the same batch, the introduced gas is again CCl._FourChange to a mixed gas of He and He3rd dryEtching was performed to remove the Si layer 4 as an intermediate layer.
[0050]
Thus, the thermoplastic material layer 20 was patterned into a relief shape according to one or more device patterns.
The patterned thermoplastic material layer is heat-treated, and the surface shape of the thermoplastic material 20 is changed to a convex curved surface shape for each device pattern by the thermal flow and surface tension of the thermoplastic material. A convex spherical shape with a curvature radius of 465 μm is obtained. was gotten.
[0051]
In the subsequent ECR etching, when the selection ratio was set to 0.5, convex spherical surfaces having a diameter of 0.5 mm and a curvature radius of 874 μm could be formed at a pitch of 0.6 mm on the quartz glass surface.
[0052]
Further, in the same manner as described above, after forming one or more convex curved shapes in the thermoplastic material, dry etching was performed with an ECR etching selectivity of 1.75. Convex spheres with a radius of curvature of 309 μm could be formed at a pitch of 0.6 mm.
[0053]
The dry etching conditions at this time are as follows.
Selection ratio: 1.75 vs. introduced gas: O₂0.5 sccM, CHF_Three26.5 sccM, reaction chamber pressure: 3-4 × 10 ~^FourTorr, microwave execution power: 620 W, RF execution power: 480 W, etching time: 450 minutes
The selection ratio is adjusted and set according to the amount of introduced gas. For a selection ratio of 0.5, O₂: 4.2 SccM, CHF_Three: 21.0 SccM.
[0054]
  Explained aboveReference examples and examplesIn addition, by adjusting / setting the selection ratio of ECR etching, the convex curved surface shape by the thermoplastic material is an example in which a convex curved surface shape having a different curvature is formed on the surface of the device material.
[0055]
  Reference examples and examplesThen, although the selection ratio of ECR etching is constant from beginning to end, the selection ratio of ECR etching can be changed with time as in the invention of claim 3. Thus, by changing the selection ratio over time, a “convex aspheric surface” can be easily formed on the surface of the device material.
[0056]
FIGS. 5A and 5B show the same state as FIGS. 1A and 1B.
[0057]
The thermoplastic material layer 2 on the device material 1 is patterned into a relief shape in accordance with the device pattern (assuming a circular shape) (FIG. 5A), and is heat-treated into a convex curve shape for each device pattern. (FIG. 5B).
[0058]
FIG. 5C shows a state in which ECR etching is performed halfway from the state of FIG. 5B with “selection ratio: 1”. When the selection ratio is changed in the state of FIG. 5 (c), for example, the selection ratio is set to 0.5 and etching is performed until the thermoplastic material is completely etched, the etching rate of the thermoplastic material becomes the device substrate. Therefore, the shape of the convex curved surface engraved on the device material 1 at the end of the etching is the convex spherical shape 2A of the original thermoplastic material as shown in FIG. 5 (d). It becomes a “convex aspherical surface” in which the top of is slightly flattened.
[0059]
By changing the change of the selection ratio with time, the shape of the convex aspheric surface engraved on the device material can be changed variously.
[0060]
In the example of FIG. 5, contrary to the above, etching is performed with a selection ratio of 0.5 from the state of FIG. 5B to the middle (FIG. 5E), and then the selection ratio is 1.0. When the etching is performed until the thermoplastic resin is completely etched, the shape engraved on the device material at the end of the etching is the original thermoplastic material as shown in FIG. The bottom portion of the convex shape 2A can be flattened so that the top portion protrudes from the bottom portion.
[0061]
As in these examples, the aspheric amount and the position of the inflection point can be changed by changing the selection ratio in the course of ECR etching.
[0062]
The change over time in the selection ratio of ECR etching is one or more of the type of introduced gas, the amount of introduced gas, the high frequency and / or microwave power for plasma generation, the temperature of the device material, and the pressure. Can be realized over time (continuous or stepwise).
[0063]
  The example described aboveThen, the convex curved surface shape formed as the surface shape of the thermoplastic material after the heat treatment is a simple single-peaked mountain shape, but the convex curved surface shape formed in the thermoplastic material is limited to such a shape. I can't.
[0064]
For example, in FIG. 6, what is patterned on the device material 1 in a relief shape according to the device pattern is a “positive type” photoresist layer 20 as a thermoplastic material layer.
For example, when the patterned photoresist layer 20 is irradiated with ultraviolet rays or the like as light within the range shown in FIG. 6A, the polymer in the photoresist is cut at the irradiated portion, and the fluidity increases. When the heat treatment is performed in such a state, since the ease of deformation is changed in the portion of the photoresist 20, for example, as shown in FIG. The shape can be realized.
[0065]
In this state, ECR etching is performed. When the selection ratio is 1, of course, the convex curved surface shape engraved in the device material 1 is the photoresist itself as in the shape 1-1 in FIG. If the selection ratio is greater than 1, the shape to be engraved is as shown in shape 1-2 of FIG. 6C, and in the opposite case, It looks like shape 1-3.
[0066]
Further, by changing the selection ratio with time, the initial surface shape (FIG. 6B) of the photoresist 20 is deformed as shown in FIG. Can be engraved on the device material 1.
[0067]
  In FIG. 7, it is manufactured by the optical device manufacturing method.Optical deviceAn example is shown.
  FIG. 7A shows an optical device in which the above manufacturing method is performed on the parallel plate-like device material 1 and a desired convex curved surface 100A is formed on one surface, and FIG. 7B shows the optical device shown in FIG. An optical device in which a light shielding film 10A is formed on a portion excluding the convex curved surface 100A is shown. When the device material 1 is a transparent material, the optical devices shown in (a) and (b) can be used as “microlenses”.
[0068]
The optical device shown in FIG. 7A also uses a “laser medium” as the device material 1 and reflects on the surface on which the convex curved surface 100A is formed and on the surface corresponding thereto (the flat surface on the lower side in the figure). By forming the surface, it can be used as a “laser resonator” as disclosed in FIG. 7 of JP-A-5-173003.
[0069]
The optical device shown in FIG. 7C is an example of the optical device in which the reflective film 11 is formed on the surface facing the surface on which the convex curved surface 100A is formed in the optical device shown in FIG. If a “half mirror” is disposed in front of the convex curved surface shape 100A, this optical device can be used as an “in-mirror microlens”.
[0070]
When the light shielding film 10A is formed as shown in FIGS. 7B and 7C, when the optical device is used as a lens, light can be effectively incident only on the lens surface portion (convex curved surface portion). The component that becomes stray light in the image forming action can be effectively removed. The “light-shielding film” may be formed, for example, by vapor deposition of a metal film, or various light-shielding materials may be formed into a film shape by printing or spraying.
[0071]
  As shown in FIG. 7D, the reflective film 11A can be formed in the region where the convex curved surface 100A is formed.it can.In such a case, it is clear that the convex curved surface portion on which the reflective film 11A is formed can be used as a convex mirror, but in this case, the device material 1 does not need to be a transparent material. When the reflective film 11A as described above is provided, if a transparent material is used as the device material 1, the convex curved surface 100A portion can be obtained by making light incident from a flat surface (surface on which the convex curved surface is not formed). The reflective film 11A can be used as a concave mirror.
[0072]
FIG.7 (e) shows the optical device which has the desired convex curved surface 100A on one surface, and the desired convex curved surface 100B on the other surface of the parallel plate-like transparent device material 1. FIG. Such an optical device can be used as a “biconvex lens”. In the optical device shown in FIG. 7E, a light-shielding film similar to the light-shielding film 10A in (b) and (c) can be provided in a portion other than the convex curved surface shapes 100A and / or 100B. The optical device shown in FIG. 7E is disclosed in FIG. 6 of JP-A-5-173003 by using “laser medium” as a device material and forming reflective surfaces on the convex curved surfaces 100A and 100B. It can be used as a “laser resonator”.
[0073]
By arranging the convex curved surfaces in the examples shown in FIGS. 7A to 7E one-dimensionally or two-dimensionally, a lens array, convex mirror array, concave mirror array, or the like can be realized. In the embodiments shown in FIGS. 7A to 7E, the initial device material is a plane-parallel plate shape. However, the present invention is not limited to this, and various shapes of device materials can be used. If a “prism-shaped one” is used, an optical device having a convex curved surface 100C on one surface of a transparent prism-shaped device material 1A can be realized as shown in FIG. This optical device can be used as an “in prism lens”.
[0074]
The example of FIG. 7F can be further generalized so that convex curved surfaces can be formed on two or more surfaces of the device material 1A, or convex curved surfaces can be arranged in an array.
The various optical devices shown in FIG. 7 can be used alone, but needless to say, these can be used in appropriate combination. In addition, it is natural that the size of the convex curved surface can be reduced to realize a micro lens, a micro lens array, a micro concave mirror, and a micro concave mirror array.
[0075]
  The optical device as shown in FIG. 7 (a) can be manufactured as a “mold”, and an optical device having a desired concave curved surface can be manufactured by molding.it can.
  That is, as shown in FIG. 8, a photocurable transparent resin 50 is applied onto the transparent substrate 15, and a mold 60 having a “convex shape corresponding to a desired concave shape” (for example, FIGS. Thus, a concave shape is formed on the transparent resin 50, and the resin layer 50 is cured by irradiating ultraviolet rays or the like from the transparent substrate 15 side.
[0076]
Thereafter, if the mold 60 is removed, a state having a desired concave shape on one side of the transparent substrate 15 can be realized. Furthermore, the concave shape of the transparent resin 50 may be engraved on the transparent substrate 15 by performing dry etching from this state. In this way, an optical device having one or more desired concave curved surfaces can be realized. Needless to say, a light-shielding film or a reflective film may be provided for such an optical device.
[0077]
【The invention's effect】
  As described above, according to the present invention,Optical device manufacturing methodCan provide.
[0078]
Since the invention described in claims 1 and 2 has the above-described configuration, a convex curved surface having a desired curvature can be formed on the device material with a high yield. According to the invention described in claim 3, a desired convex aspheric surface can be easily formed on the device surface.
[0079]
  Claims 1-4In this invention, even when the thermoplastic material layer is thick, a relief pattern can be accurately formed according to the device pattern.
[0080]
  Also,An optical device having a desired concave curved surface can be manufactured efficiently and at low cost.
[0081]
  The optical device manufactured by the above method isThe accuracy with respect to the radius of curvature and the like is good, the formation of an aspherical shape is easy, and the production yield is good.
[Brief description of the drawings]
[Figure 1]The basic principle of the inventionIt is a figure for demonstrating.
FIG. 2 shows a thickness of a thermoplastic material layer formed on a device material: d and a convex curved surface after heat treatment.
It is a graph for demonstrating the relationship of the curvature radius of a shape.
[Fig. 3]It is a figure for demonstrating patterning by making a thermoplastic material layer into a photoresist.
[Fig. 4]Claim 1It is a figure for demonstrating the characteristic part of invention of this invention.
[Figure 5]Formation of aspheric shape by changing selectivity over timeIt is a figure for demonstrating.
FIG. 6 is a view for explaining a modified embodiment of the first and third aspects of the present invention.
[Fig. 7]Examples of optical devicesIt is a figure for demonstrating.
FIG. 8 is a diagram for explaining an optical device having a concave curved surface shape manufactured using the optical device as a mold.
[Explanation of symbols]
  1 Device material
  2 Thermoplastic material layer
  2A Convex curve shape of the surface of the thermoplastic material after heat treatment
  1A Convex curved surface engraved on device material

Claims (4)

A thermoplastic material layer having a predetermined thickness is formed on a flat surface of the device material, and the thermoplastic material layer is patterned into a relief shape in accordance with one or more device patterns, and then the patterned thermoplastic material layer is heat-treated. Then, after making the surface shape of the thermoplastic material into a convex curve shape for each device pattern by the thermal flow and surface tension of the thermoplastic material, ECR etching is performed on the thermoplastic material and the device material, and the above heat A method of manufacturing an optical device having one or more convex curved surfaces having a desired curvature on a surface of a device material by engraving one or more convex curved surfaces in a plastic material on the device material,
The intermediate layer and the thin photoresist layer are laminated on the thermoplastic material layer, and the thin photoresist layer is patterned according to one or more device patterns by a photolithography method, and the patterned photoresist layer is used as a mask. First dry etching is performed on the intermediate layer, the photoresist pattern is copied onto the intermediate layer, and the second dry etching is performed on the thermoplastic material layer using the intermediate layer pattern as a mask. Removing the photoresist layer on the mask of the layer , patterning the thermoplastic material layer into a relief shape according to the device pattern, and further performing a third dry etching to remove the intermediate layer Removing the intermediate layer,
An optical device characterized in that an ECR etching selection ratio is adjusted and set according to the magnitude relationship between the curvature of the convex curved surface shape of the surface of the thermoplastic material and the curvature of the convex curved surface to be formed on the surface of the device material. Production method. The optical device manufacturing method according to claim 1,
An optical device manufacturing method, wherein a curvature of a convex curved surface shape of a surface of a thermoplastic material is set larger than a curvature of a convex curved surface to be formed on a device surface, and a selection ratio of ECR etching is adjusted and set small. A thermoplastic material layer having a predetermined thickness is formed on a flat surface of the device material, and the thermoplastic material layer is patterned into a relief shape in accordance with one or more device patterns, and then the patterned thermoplastic material layer is heat-treated. Then, after making the surface shape of the thermoplastic material into a convex curve shape for each device pattern by the thermal flow and surface tension of the thermoplastic material, ECR etching is performed on the thermoplastic material and the device material, and the above heat A method of manufacturing an optical device having one or more desired convex aspheric surfaces on a surface of a device material by engraving one or more convex curved surfaces of a plastic material on the device material,
The intermediate layer and the thin photoresist layer are laminated on the thermoplastic material layer, and the thin photoresist layer is patterned according to one or more device patterns by a photolithography method, and the patterned photoresist layer is used as a mask. First dry etching is performed on the intermediate layer, the photoresist pattern is copied onto the intermediate layer, and the second dry etching is performed on the thermoplastic material layer using the intermediate layer pattern as a mask. Removing the photoresist layer on the mask of the layer , patterning the thermoplastic material layer into a relief shape according to the device pattern, and further performing a third dry etching to remove the intermediate layer Removing the intermediate layer,
According to the shape relationship between the convex curved surface shape of the thermoplastic material surface and the convex aspheric surface to be formed on the surface of the device material, the selection ratio of ECR etching is changed over time, Optical device manufacturing method. In the manufacturing method of the optical device of Claim 1 or 2 or 3,
Adjustment / setting of ECR etching selection ratio or change over time can be selected from the type of introduced gas, the amount of introduced gas, the high frequency and / or microwave power for plasma generation, the temperature of the device material, and the pressure. An optical device manufacturing method characterized by performing one or more adjustments / settings or changes over time.

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