JP5094535B2 - Recess formation method, uneven product manufacturing method, light emitting element manufacturing method, and optical element manufacturing method - Google Patents

Description

  The present invention relates to a recess forming method for satisfactorily forming a recess in a heat mode type photoresist layer, and a method for manufacturing an uneven product, a method for manufacturing a light emitting element, and a method for manufacturing an optical element using this method.

  Conventionally, as a method for forming irregularities on a predetermined object such as an optical disc, a master for manufacturing an optical disc, or a light emitting element having irregularities on a light emitting surface, for example, a photoresist material as shown in Patent Document 1 A method of using is known. Specifically, in this method, a coating step of applying a photoresist to the master, an exposure step of exposing the photoresist with laser light, and a developing step of forming a predetermined recess by removing the exposed portion with a developer. Then, an etching process for etching the master disk by reactive ion etching (hereinafter also referred to as “RIE”) and a peeling process for stripping the remaining resist are performed to form irregularities on the master disk.

Japanese Patent Laid-Open No. 7-161080

  By the way, the inventor of the present application has devised a method that is more suitable than the prior art using a photoresist and RIE as a method for forming irregularities. Specifically, the method is an etching method in which a heat mode type photoresist material in which holes are formed by irradiation of a focused laser beam is used instead of the above-described photoresist material that requires development. According to this method, since the concave portion is formed in the irradiated portion only by irradiating the laser beam, the developing step as in the prior art is not required, and the manufacturing time can be shortened.

  However, in the method using a heat mode type photoresist material, a hole is formed by causing chemical or / and physical changes such as decomposition, sublimation, vaporization, and scattering in the portion irradiated with the laser beam. At times, foreign matter is generated. Therefore, if foreign matter remains around the hole formed in the heat mode type photoresist material, there has been a problem that etching cannot be performed properly thereafter and a good uneven shape cannot be formed.

  The inventor of the present application also considers forming irregularities by leaving the heat mode photoresist material in which concave portions are formed by laser light irradiation without performing the above-described etching. Even in such a case, there is a problem that if the foreign matter remains around the hole as described above, a good uneven shape cannot be formed.

  Accordingly, the present invention provides a method for forming a recess that can suppress the influence of foreign matter that occurs when forming a recess in a heat mode type photoresist layer, a method for manufacturing an uneven product using this method, and a light emitting device. It is an object to provide a manufacturing method and a manufacturing method of an optical element.

In order to achieve the above object, the method for forming a recess according to the present invention irradiates light collected from an optical system including a light source on a photoresist layer capable of heat mode shape change. A method of forming a plurality of recesses in the recess, wherein the recess formation surface of the photoresist layer is directed in the direction of gravity and light is irradiated from the opposite side to the recess formation surface to form the recesses on the recess formation surface. It is characterized by doing.
Here, in the present invention, the gravitational direction refers to the direction in which the gravitational field is directed, that is, the direction in which the object falls.

  According to such a recess formation method, the recess is formed with the recess formation surface of the photoresist layer directed in the direction of gravity, so the condensed light is irradiated onto the photoresist layer capable of heat mode shape change. Thus, foreign matters generated when forming the recesses can be dropped. Thereby, since it can suppress that a foreign material remains in a hole (concave part) and its circumference | surroundings, a favorable uneven | corrugated shape can be formed.

Moreover, the recessed part formation method of this invention is good also as forming a recessed part, applying an ion wind to the recessed part formation surface of the said photoresist layer.
According to this, since the recess forming surface (the hole and its surroundings) and the foreign matter can be charged to the same charge, the electrostatic repulsion force actively suppresses the foreign matter from adhering to the concave portion and its surroundings. And a more favorable uneven shape can be formed.

  In addition, the method for forming a recess according to the present invention provides the reference surface provided on the photoresist layer or a reference surface provided separately from the photoresist layer during or after the formation of the recess in the photoresist layer. An inspection light irradiation step of irradiating inspection light from the optical system, a detection step of detecting the amount of inspection light reflected or diffracted from the reference plane, and the light amount to be a predetermined amount based on the detected light amount An output adjustment step of adjusting the output of the light source.

  In the concave portion forming method of the present invention, there is a possibility that the fallen foreign matter may adhere to the objective lens of the optical system. Therefore, the inspection light is reflected or diffracted by irradiating the reference surface with inspection light during or after the formation of the concave portion. By detecting this and adjusting the output of the light source, it is possible to always form the recess with a predetermined amount of light. Thereby, a favorable uneven | corrugated shape can be formed.

Further, the recess forming method of the present invention irradiates the photoresist layer with a plurality of recesses by irradiating light condensed from an optical system including a light source on the photoresist layer capable of changing the shape of the heat mode. A method of forming a recess, wherein the recess is formed with the recess forming surface of the photoresist layer directed in the direction of gravity , and is provided in the photoresist layer during or after the formation of the recess in the photoresist layer. An inspection light irradiation step of irradiating inspection light from the optical system onto a reference surface provided separately from the reference surface or the photoresist layer, and a detection step of detecting the amount of inspection light reflected or diffracted from the reference surface; If the amount of light detected is smaller than a predetermined amount, a cleaning step for cleaning the optical system of the objective lens after the formation of the recess to the photoresist layer, Ru comprising a.

  According to this, since the foreign matter adhering to the objective lens after the formation of the concave portion can be cleaned (removed), the next time the concave portion is formed, the surface of the objective lens can be irradiated with light without any foreign matter. Therefore, a favorable uneven shape can be formed. Further, during or after the formation of the recess, the reference surface is irradiated with inspection light, and the reflected or diffracted inspection light is detected and cleaning is performed when the amount of light is smaller than a predetermined amount. Possibility can be reduced and, as a result, it contributes to formation of favorable uneven | corrugated shape.

  In addition, the recessed part formation method which concerns on this invention as mentioned above can be utilized for the manufacturing method of uneven | corrugated products, such as a semiconductor and an optical disk, the manufacturing method of a light emitting element, and the manufacturing method of an optical element.

  According to the present invention, it is possible to suppress the influence of foreign matter generated when forming a recess in the heat mode type photoresist layer, so that a favorable uneven shape can be formed.

[First Embodiment]
Next, a method for manufacturing a light emitting device according to the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 (a) is a view of an LED package, and (b) is an enlarged view of (a).

As shown in FIG. 1A, an LED package 1 as an example of a light emitting element according to the present embodiment includes an LED element 10 that is an example of a light emitter, and a case 20 for fixing and wiring the LED element 10. And comprising.
The LED element 10 is a conventionally known element, and has an n-type cladding layer, a p-type cladding layer, an active layer, and the like, although details are not shown. In FIG. 1A, the upper surface is a light emitting surface 18 from which light is emitted to the outside.

  The LED element 10 is fixed to the case 20. In the case 20, wirings 21, 22 and the like for supplying power to the LED element 10 are formed.

As shown in FIG. 1B, the LED element 10 includes a light emitting part 11 that is a main body part for emitting light, a photoresist layer 12 formed on the light emitting part 11 (light emitting surface 18), and a barrier layer. 13 in this order.
The photoresist layer 12 is a layer in which light is converted into heat by irradiation of intense light, and the shape of the material can be changed by this heat to form a recess, and is a so-called heat mode type photoresist layer. . Conventionally, such a photoresist has been widely used in a recording layer such as an optical recording disk. Can be used.

The photoresist layer 12 in the present invention is preferably a dye type containing a dye as a recording substance.
Accordingly, examples of the recording material contained in the photoresist layer 12 include organic compounds such as dyes. The material of the photoresist layer 12 is not limited to an organic material, and an inorganic material or a composite material of an inorganic material and an organic material can be used. However, since an organic material can be easily formed by spin coating and a material having a low transition temperature can be easily obtained, it is preferable to use an organic material. Among organic materials, it is preferable to employ a dye whose light absorption can be controlled by molecular design.

  Here, suitable examples of the photoresist layer 12 include methine dyes (cyanine dyes, hemicyanine dyes, styryl dyes, oxonol dyes, merocyanine dyes, etc.), macrocyclic dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), Examples include azo dyes (including azo metal chelate dyes), arylidene dyes, complex dyes, coumarin dyes, azole derivatives, triazine derivatives, 1-aminobutadiene derivatives, cinnamic acid derivatives, and quinophthalone dyes.

  Among these, a dye-type photoresist layer 12 that can record information only once with a laser beam is preferable. This is because an organic photoresist can be dissolved in a solvent and formed into a film by spin coating or spray coating, so that it is excellent in productivity. The dye-type photoresist layer 12 preferably contains a dye having absorption in the recording wavelength region. In particular, the upper limit of the extinction coefficient k indicating the amount of light absorption is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, and most preferably 1 or less from the viewpoint of improving processing accuracy. Further, the lower limit value of the extinction coefficient k is preferably 0.0001 or more, more preferably 0.001 or more, and further preferably 0.1 or more, from the viewpoint of improving the processing speed.

The photoresist layer 12 needs to absorb light at the recording wavelength as described above. From such a viewpoint, a dye can be appropriately selected or the structure can be modified according to the wavelength of the laser light source. it can.
For example, when the oscillation wavelength of the laser light source is around 780 nm, it is advantageous to select from pentamethine cyanine dye, heptamethine oxonol dye, pentamethine oxonol dye, phthalocyanine dye, naphthalocyanine dye, and the like.
When the oscillation wavelength of the laser light source is around 660 nm, it is advantageous to select from trimethine cyanine dye, pentamethine oxonol dye, azo dye, azo metal complex dye, pyromethene complex dye, and the like.
Further, when the oscillation wavelength of the laser light source is around 405 nm, monomethine cyanine dye, monomethine oxonol dye, zero methine merocyanine dye, phthalocyanine dye, azo dye, azo metal complex dye, porphyrin dye, arylidene dye, complex It is advantageous to select from dyes, coumarin dyes, azole derivatives, triazine derivatives, benzotriazole derivatives, 1-aminobutadiene derivatives, quinophthalone dyes, and the like.

  Examples of preferable compounds as the photoresist layer 12 (recording layer compound) are shown below when the oscillation wavelength of the laser light source is around 780 nm, around 660 nm, and around 405 nm. Here, the compounds (I-1 to I-10) represented by the following chemical formulas 1 and 2 are compounds when the oscillation wavelength of the laser light source is around 780 nm. Moreover, the compounds (II-1 to II-8) represented by the chemical formulas 3 and 4 are compounds in the case of around 660 nm. Furthermore, the compounds (III-1 to III-14) represented by the chemical formulas 5 and 6 are compounds in the case of around 405 nm. In addition, this invention is not limited to the case where these are used for a recording layer compound.

<Example of photoresist material when the oscillation wavelength of the laser light source is around 780 nm>

<Example of photoresist material when the oscillation wavelength of the laser light source is around 780 nm>

<Example of photoresist material when the oscillation wavelength of the laser light source is around 660 nm>

<Example of photoresist material when the oscillation wavelength of the laser light source is around 660 nm>

<Example of photoresist material when the oscillation wavelength of the laser light source is around 405 nm>

<Example of photoresist material when the oscillation wavelength of the laser light source is around 405 nm>

  JP-A-4-74690, JP-A-8-127174, 11-53758, 11-334204, 11-334205, 11-334206, 11-334207 The dyes described in JP-A-2000-43423, JP-A-2000-108513, JP-A-2000-158818, and the like are also preferably used.

The dye-type photoresist layer 12 is prepared by dissolving the dye in a suitable solvent together with a binder or the like to prepare a coating solution, and then coating the coating solution on a substrate or a light reflection layer described later. And after forming a coating film, it can form by drying. In that case, it is preferable that the temperature of the surface which apply | coats a coating liquid is the range of 10-40 degreeC. More preferably, the lower limit is 15 ° C. or higher, more preferably 20 ° C. or higher, and particularly preferably 23 ° C. or higher. Moreover, as an upper limit, it is more preferable that it is 35 degrees C or less, It is more preferable that it is 30 degrees C or less, It is especially preferable that it is 27 degrees C or less. As described above, when the surface temperature to be applied is in the above range, it is possible to prevent the occurrence of coating unevenness and coating failure and make the thickness of the coating film uniform.
Each of the upper limit value and the lower limit value can be arbitrarily combined.
Here, the photoresist layer 12 may be a single layer or a multilayer. In the case of a multilayer structure, the photoresist layer 12 is formed by performing the coating process a plurality of times.
The concentration of the dye in the coating solution is generally in the range of 0.01 to 15% by mass, preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.5 to 5% by mass, most preferably. It is the range of 0.5-3 mass%.

  Examples of the solvent for the coating solution include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; dimethylformamide and the like Amides; Hydrocarbons such as methylcyclohexane; Ethers such as tetrahydrofuran, ethyl ether, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; 2,2,3,3-tetrafluoropropanol, etc. Fluorinated solvents; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether; That.

  Preferably, butyl acetate, ethyl lactate; ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; fluorine-based solvent such as 2,2,3,3-tetrafluoropropanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl Glycol ethers such as ether and propylene glycol monomethyl ether, n-butanol diacetone alcohol, 2,2,3,3-tetrafluoropropanol, and propylene glycol monomethyl ether are more preferable.

  The said solvent can be used individually or in combination of 2 or more type in consideration of the solubility of the pigment | dye to be used. In the coating solution, various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be added according to the purpose.

Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, a doctor blade method, and a screen printing method. In addition, it is preferable to employ the spin coating method in terms of excellent productivity and easy control of the film thickness.
The photoresist layer 12 (recording layer compound) is preferably dissolved in an organic solvent in an amount of 0.3 wt% or more and 30 wt% or less from the viewpoint that it is advantageous for formation by a spin coating method. It is more preferable to dissolve by. In particular, it is preferable to dissolve in tetrafluoropropanol at 1 wt% or more and 20 wt% or less. The recording layer compound preferably has a thermal decomposition temperature of 150 ° C. or higher and 500 ° C. or lower, more preferably 200 ° C. or higher and 400 ° C. or lower.
At the time of application, the temperature of the coating solution is preferably in the range of 23 to 50 ° C, more preferably in the range of 24 to 40 ° C, and particularly preferably in the range of 25 to 30 ° C.

  When the coating solution contains a binder, examples of the binder include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin, and rubber; hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene; Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin And synthetic organic polymers such as initial condensation products of thermosetting resins such as rubber derivatives and phenol / formaldehyde resins. When a binder is used in combination as a material for the photoresist layer 12, the amount of the binder used is generally in the range of 0.01 to 50 times (mass ratio) with respect to the dye, preferably 0.1. It exists in the range of double amount-5 times amount (mass ratio).

The photoresist layer 12 can contain various anti-fading agents in order to improve the light resistance of the photoresist layer 12.
As the antifading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used.
Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19587, and 60-35054. 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, JP-A-60-47069, JP-A-63-209995, JP-A-4-25492, JP-B-1-38680, JP-A-6-26028, etc., German Patent 350399, and Japan Examples include those described in Chemical Society Journal, October 1992, page 1141. The amount of the antifading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 45% by mass, based on the amount of the dye. Preferably, it is the range of 3-40 mass%, Most preferably, it is the range of 5-25 mass%.

  The solvent coating method in the case where the photoresist layer 12 is a dye-type recording layer has been described above. However, the photoresist layer 12 may be formed by a film forming method such as vapor deposition, sputtering, or CVD in accordance with the physical properties of the recording material. it can.

In addition, the pigment | dye has a higher light absorptivity in the wavelength of the laser beam used for the process of the recessed part 15 mentioned later than another wavelength. In particular, it is desirable that the light absorptance is higher at the wavelength of the laser light during processing than the light emission wavelength of the light emitting element such as the LED element 10.
The wavelength of the absorption peak of the dye is not necessarily limited to that in the visible light wavelength range, and may be in the ultraviolet range or the infrared range.

In particular, when the refractive index of the material constituting the light emitting surface of the light emitting element is high, the refractive index of the photoresist layer 12 and the barrier layer 13 constituting the recess 15 is preferably high.
The dye has a wavelength range with a high refractive index on the long wave side of the peak wavelength of the absorption wavelength, and it is preferable to match this wavelength range with the emission wavelength of the light emitting element. For this purpose, the dye absorption wavelength λa is preferably shorter than the center wavelength λc of the light emitting element (λa <λc). From the viewpoint of ease of processing, the lower limit of the difference between λa and λc is preferably 10 nm or more, more preferably 25 nm or more, and further preferably 50 nm or more. The upper limit of the difference between λa and λc is preferably 500 nm or less, more preferably 300 nm or less, and further preferably 200 nm or less, from the viewpoint of ease of processing.

The wavelength λw for recording the recess 15 with a laser is preferably in a relationship of λa <λw. With such a relationship, the light absorption amount of the dye is appropriate, the recording efficiency is increased, and a clean uneven shape can be formed. Further, it is preferable that λw <λc. Since λw should be the wavelength that the dye absorbs, the light emitted from the light-emitting element is not absorbed by the dye and the transmittance is improved by having the center wavelength λc of the light-emitting element on the longer wavelength side than the wavelength of λw. As a result, the luminous efficiency can be improved.
From the above viewpoint, it can be said that the relationship of λa <λw <λc is most preferable.

  The wavelength λw of the laser light for forming the recess 15 may be any wavelength that can provide a large laser power. For example, when a dye is used for the photoresist layer 12, 193 nm, 210 nm, 266 nm, 365 nm, 405 nm It is preferably 1000 nm or less, such as 488 nm, 532 nm, 633 nm, 650 nm, 680 nm, 780 nm, 830 nm.

  The laser beam may be any laser such as a gas laser, a solid laser, or a semiconductor laser. However, in order to simplify the optical system, it is preferable to employ a solid-state laser or a semiconductor laser. The laser light may be continuous light or pulsed light, but it is preferable to employ laser light whose emission interval can be freely changed. For example, it is preferable to employ a semiconductor laser. When the laser cannot be directly on / off modulated, it is preferable to modulate with an external modulation element.

  Further, the laser power is preferably higher in order to increase the processing speed. However, as the laser power is increased, the scanning speed (the speed at which the photoresist layer 12 is scanned with laser light; for example, the rotational speed of the optical disk drive described later) must be increased. Therefore, the upper limit value of the laser power is preferably 100 W in consideration of the upper limit value of the scanning speed, more preferably 10 W, still more preferably 5 W, and most preferably 1 W. The lower limit of the laser power is preferably 0.1 mW, more preferably 0.5 mW, and even more preferably 1 mW.

  Further, the laser light is preferably light that has excellent transmission wavelength width and coherency and can be narrowed down to a spot size that is comparable to the wavelength. As a recording strategy (light pulse irradiation conditions for properly forming the recess 15), it is preferable to adopt a strategy used in an optical disc. That is, it is preferable to adopt conditions such as recording speed, the peak value of the laser beam to be irradiated, and the pulse width as used in an optical disc.

The thickness of the photoresist layer 12 should correspond to the depth of the recess 15 described later.
The thickness can be set as appropriate within a range of, for example, 1 to 10000 nm. The lower limit of the thickness is that the optical effect by the recess 15 and the etching effect are obtained when the photoresist layer 12 is used as an etching mask. From the viewpoint, 10 nm or more is preferable, and 30 nm or more is more preferable. Further, the upper limit of the thickness is preferably 1000 nm or less, and more preferably 500 nm or less, from the viewpoint of processing accuracy and processing speed.

  The thickness t of the photoresist layer 12 and the diameter d of the recess 15 are preferably in the following relationship. That is, the upper limit of the thickness t of the photoresist layer 12 is preferably t <10d, more preferably t <5d, and even more preferably t <3d from the viewpoint of processing accuracy and processing speed. The lower limit of the thickness t of the photoresist layer 12 is preferably t> d / 100 from the viewpoint of obtaining an optical effect due to the recess 15 and an etching effect when the photoresist layer 12 is used as an etching mask. t> d / 10 is more preferable, and t> d / 5 is more preferable.

  When the photoresist layer 12 is formed, a coating solution is prepared by dissolving or dispersing a substance to be a photoresist in an appropriate solvent, and then the coating solution is applied by a coating method such as spin coating, dip coating, or extrusion coating. It can be formed by applying to the surface of the light emitting surface 18.

The barrier layer 13 is formed and optionally provided to prevent the photoresist layer 12 from impact or the like. The barrier layer 13 is not particularly limited as long as it is a transparent material, but is preferably polycarbonate, cellulose triacetate, or the like, and more preferably a material having a moisture absorption rate of 5% or less at 23 ° C. and 50% RH. Further, oxides and sulfides such as SiO ₂ , ZnS, and GaO can be used.
“Transparent” means that the light emitted from the LED element 10 is so transparent that the light is transmitted (transmittance: 90% or more).

  The barrier layer 13 is prepared by dissolving a photocurable resin constituting the adhesive layer in an appropriate solvent to prepare a coating solution, and then coating the coating solution on the photoresist layer 12 at a predetermined temperature to form a coating film. For example, a cellulose triacetate film (TAC film) obtained by, for example, plastic extrusion is laminated on the coating film, and light is irradiated from above the laminated TAC film to cure the coating film. The TAC film preferably contains an ultraviolet absorber. The thickness of the barrier layer 13 is in the range of 0.01 to 0.2 mm, preferably in the range of 0.03 to 0.1 mm, and more preferably in the range of 0.05 to 0.095 mm.

  A plurality of recesses 15 are periodically formed in the photoresist layer 12 and the barrier layer 13. The concave portion 15 is formed by irradiating the condensed light on the photoresist layer 12 and the barrier layer 13 to deform the irradiated portion (including deformation due to disappearance). It is desirable to form the recesses 15 densely in a range where the light emitted from the light emitting surface 18 is emitted.

The principle of forming the recess 15 is as follows.
When the photoresist layer 12 (recording layer compound) is irradiated with laser light having a wavelength at which the material absorbs light (wavelength absorbed by the material), the photoresist layer 12 absorbs the laser light, and the absorbed light is absorbed. It is converted into heat, and the temperature of the irradiated part rises. This causes the photoresist layer 12 to undergo chemical or / and physical changes such as softening, liquefaction, vaporization, sublimation, and decomposition. And the recessed part 15 is formed because the material which caused such a change moves or / and lose | disappears. In addition, since the barrier layer 13 is a very thin layer, it moves or / and disappears together with the movement or / and disappearance of the photoresist layer 12. When such a recess 15 is formed, a part of the photoresist layer 12 that is chemically or / and physically changed remains as a foreign matter around the recess 15.

  In addition, as a formation method of the recessed part 15, the formation method of the pit employ | adopted, for example with a write-once optical disk, a write-once optical disk, etc. is applicable. Specifically, for example, a method of forming uniform pits by detecting the intensity of reflected laser light that varies depending on the pit size and correcting the laser output so that the intensity of the reflected light is constant. Can be applied.

  Further, the vaporization, sublimation or decomposition of the photoresist layer 12 (recording layer compound) as described above preferably has a large rate of change and is steep. Specifically, the weight reduction rate by differential thermal balance (TG-DTA) during vaporization, sublimation or decomposition of the recording layer compound is preferably 5% or more, more preferably 10% or more, and even more preferably 20%. That's it. Further, it is preferable that the slope of weight reduction (weight reduction rate per 1 ° C. temperature increase) by a differential thermal balance (TG-DTA) during vaporization, sublimation or decomposition of the recording layer compound is 0.1% / ° C. or more. More preferably, it is 0.2% / ° C or more, and further preferably 0.4% / ° C or more.

  In addition, the upper limit of the transition temperature of chemical or / and physical change such as softening, liquefaction, vaporization, sublimation, and decomposition is preferably 2000 ° C. or lower, more preferably 1000 ° C. or lower, from the viewpoint of improving the processing speed. More preferably, it is not higher than ° C. If the temperature is too high, there is a possibility that the laser power is insufficient and processing cannot be performed. Further, the lower limit of the transition temperature is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, and further preferably 150 ° C. or higher, from the viewpoint of processing accuracy.

FIG. 2A is a diagram of an example of the light emitting surface viewed in plan, FIG. 2B is a diagram of another example, and FIG. 3A illustrates the relationship between the diameter and pitch of the recesses. It is a figure explaining, (b) is a figure explaining the relationship between the light emission time of a laser beam, and a period.
As shown in FIG. 2A, the recess 15 can be formed in a dot shape, and the dots arranged in a lattice shape. Moreover, as shown in FIG.2 (b), the recessed part 15 may be formed in the shape of an elongate groove | channel, and this may connect intermittently. Further, although not shown, it can be formed as a continuous groove shape.

  The pitch P between the adjacent recesses 15 is 0.01 to 100 times the center wavelength λc of the light emitted by the LED element 10 that is a light emitter.

  The pitch P of the recesses 15 is preferably 0.05 to 20 times the center wavelength λc, more preferably 0.1 to 5 times, and most preferably 0.2 to 2 times. Specifically, the lower limit value of the pitch P is preferably 0.01 times or more of the center wavelength λc, more preferably 0.05 times or more, further preferably 0.1 times or more, and most preferably 0.2 times or more. . Further, the upper limit value of the pitch P is preferably 100 times or less of the center wavelength λc, more preferably 20 times or less, further preferably 5 times or less, and most preferably 2 times or less.

The diameter of the recess 15 or the width of the groove is 0.005 to 25 times the center wavelength λc, preferably 0.025 to 10 times, more preferably 0.05 to 2.5 times, and most preferably 0.25. ~ 2 times.
Here, the diameter or the width of the groove is a size at a half depth of the recess 15, a so-called half-value width.

  The diameter of the recess 15 or the width of the groove can be appropriately set within the above range, but depending on the size of the pitch P so that the refractive index gradually decreases macroscopically as the distance from the light emitting surface 18 increases. It is desirable to adjust. That is, when the pitch P is large, the diameter of the recess 15 or the width of the groove is preferably increased, and when the pitch P is small, the diameter of the recess 15 or the width of the groove is preferably decreased. From this viewpoint, the diameter or the width of the groove is preferably about a half of the pitch P, for example, 20 to 80%, more preferably 30 to 70% of the pitch P. More preferably, it is 40 to 60%.

  The depth of the recess 15 is preferably 0.01 to 20 times the center wavelength λc, more preferably 0.05 to 10 times, still more preferably 0.1 to 5 times, and most preferably 0.2. ~ 2 times.

A method for manufacturing the LED package 1 having the above configuration will be described. 4A to 4C are diagrams showing the manufacturing process of the LED package.
As shown in FIG. 4A, first, a light emitting unit 11 (substrate 100) which is a main body of the LED element 10 manufactured by a conventionally known method is prepared. Here, the substrate 100 is obtained by forming a semiconductor light emitting element substrate on which a plurality of LED elements 10 are formed in a disk shape or a rectangular shape.

  Then, as shown in FIG. 4B, a photoresist layer 12 and a barrier layer 13 are formed in this order on the light emitting portion 11.

  Next, the recess 15 is formed. As an apparatus for forming the recess 15, an optical disk drive DD as shown in FIG. 5 can be used. Specifically, the optical disc drive DD includes a holder 30 that holds the substrate 100, a motor 40 that rotates the holder 100 to rotate the substrate 100 (the main body of the LED element 10), the photoresist layer 12, and the barrier. The optical system 50 that irradiates the light condensed on the layer 13, a control device CA, and an ion wind generator 60 that applies ion wind to the photoresist layer 12 and the barrier layer 13 are mainly provided.

The cage 30 mainly includes a main body 31 and a plurality of arms 32.
The main body portion 31 is formed in a disk shape, and the lower side is an attachment portion (mounting portion) of the substrate 100. A plurality of arms 32 are provided at equal intervals on the outer peripheral portion of the main body 31.

  The arm 32 is a flexible member having one end fixed to the main body 31, and the other end bent in a hook shape holds the outer periphery of the substrate 100 at a position close to the substrate 100 shown in FIG. To do. With such a holder 30, the optical disc drive DD can hold the substrate 100 in which no hole is formed at the center and form a recess.

  The substrate 100 is held by the cage 30 with the surface on which the photoresist layer 12 and the barrier layer 13 are formed, that is, the surface on which the recess 15 is formed (hereinafter referred to as the recess forming surface 12A) facing downward. . At this time, the angle formed by the recessed portion forming surface 12A with respect to the horizontal direction is preferably within ± 90 degrees (the recessed portion forming surface 12A is directed downward from the horizontal direction), and is within ± 5 degrees. Is more preferable, and it is even more preferable that the angle is 0 degrees (the recess forming surface 12A faces the direction of gravity).

The motor 40 is disposed above the retainer 30, that is, above the substrate 100, and the end of the rotating shaft is fixed to the center of the main body 31.
Here, in the optical disc drive DD of the present embodiment, since the motor 40 is disposed above the substrate 100, dust generated from the motor 40 may fall onto the substrate 100. Therefore, although not illustrated, an exhaust port is provided in the housing of the motor 40, and the dust generated from the motor 40 is exhausted to the outside by decompressing the inside of the housing with a pump or the like and sucking air in the housing. It is preferable to do.

  The optical system 50 is disposed at a position below the substrate 100, and includes a laser light source 51 as an example of a light source, a first lens 52, a second lens 53, a half mirror 54, a third lens 55 as an example of an objective lens, A fourth lens 56 and a detector 57 are mainly provided. The optical system 50 is configured to be movable in the radial direction of the substrate 100 (left-right direction in FIG. 5) by a known mechanism.

  The laser light source 51 emits laser light, and its output is adjusted by the control device CA.

  The first lens 52 expands the beam diameter of the laser light emitted from the laser light source 51, and is disposed on the downstream side of the laser light source 51 (downstream side in the traveling direction of the laser light).

  The second lens 53 converts the laser beam expanded in diameter by the first lens 52 into a parallel light beam, and is disposed on the downstream side of the first lens 52.

  The half mirror 54 is disposed on the downstream side of the second lens 53, transmits the laser light emitted from the laser light source 51, and transmits the laser light returning from the opposite side in a predetermined direction (the laser light). The light is reflected in a direction substantially orthogonal to the optical axis direction.

  The third lens 55 is for condensing the laser light that has passed through the half mirror 54, and is arranged to face the substrate 100 on the downstream side of the half mirror 54 and below the substrate 100. .

  The fourth lens 56 collects the laser light reflected by the half mirror 54 and is disposed on the optical path of the laser light reflected by the half mirror 54.

  The detector 57 is disposed on the downstream side of the fourth lens 56 and has a function of detecting the amount of laser light collected by the fourth lens 56. The amount of light detected by the detector 57 is output to the control device CA. As the detector 57, for example, a photodiode, a divided photodiode, or the like can be employed.

  The control device CA includes known hardware (not shown) such as a CPU, a ROM, a RAM, a communication device, and the like. In the present embodiment, the light amount is determined based on the light amount detected by the detector 57. Control is performed to adjust the output of the laser light source 51 so that the quantity is constant. Here, the predetermined amount may be one value or a value having a predetermined width (a predetermined range from an upper limit value to a lower limit value).

Here, the output adjustment method of the laser light source 51 by the control device CA will be described.
First, at a predetermined timing during or after the formation of the recess 15 on the recess forming surface 12A (photoresist layer 12) of the substrate 100 using the optical disc drive DD, A standard plate (such as a silicon substrate) having an area (reference surface) with a known reflectance at least partially is set.

  Next, the control device CA irradiates the reference surface with laser light (inspection light) from the optical system 50 (inspection light irradiation step). The inspection light is emitted from the laser light source 51, passes through the first lens 52, the second lens 53, the half mirror 54, and the third lens 55, and is irradiated onto the reference surface from the third lens 55 that is an objective lens.

  The inspection light irradiated on the reference surface is reflected by the reference surface, passes through the third lens 55 again, is reflected by the half mirror 54 in a predetermined direction, is condensed by the fourth lens 56, and is applied to the detector 57. Led. The detector 57 generates a servo signal for focusing by using a focusing technique similar to a known optical disc drive, for example, an astigmatism method or a knife edge method, and outputs the servo signal to the control device CA.

  Upon receiving the servo signal, the control device CA controls the optical system 50 and continues to irradiate the reference surface with the inspection light for a predetermined time in a state where focusing is performed, and detects the total amount of inspection light guided to the detector 57. The amount of inspection light reflected by the reference surface (hereinafter also referred to as return light amount) is detected (detection step).

  In general, the amount of return light can be estimated by the control device CA from the amount of inspection light emitted from the laser light source 51 (output of the laser light source 51), the reflectance of the reference surface, and the like. However, in this embodiment, since the optical system 50 is disposed below the substrate 100, foreign matter generated due to the formation of the recess 15 may adhere to the third lens 55 that is the objective lens. For this reason, the amount of return light detected by the detector 57 may be smaller than the amount of light that can be estimated by the control device CA.

  Therefore, the control device CA adjusts the output of the laser light source 51 so that the detected return light amount becomes a predetermined amount set in advance based on the light amount of the laser light emitted from the laser light source 51, the material of the photoresist layer 12, and the like. (Output adjustment process). Specifically, the output of the laser light source 51 is increased when the detected amount of return light is insufficient compared to the predetermined amount.

  The ion wind generator 60 generates an ion wind by charging the molecules in the air to a negative charge when forming the recess, and the processed portion of the recess forming surface 12A from the outlet 61 (the recess 15 is formed by light irradiation). It is configured to send out toward the formed part). As a method for generating the ion wind, for example, a method using voltage application, a method for crushing water, a method using radiation or ultraviolet rays, and the like can be used. Among these, a method using voltage application is preferable. There are a corona discharge method and an electron emission method as a method of applying a voltage, but the electron emission method is particularly preferable because it can stably generate an ionic wind and can also stabilize the effect of preventing scattered objects from adhering. . The ion wind generator 60 is configured to be movable together with the optical system 50.

  Note that the portion of the substrate 100 to which the ion wind is applied is not limited to the processed portion, and may be, for example, a part of the recessed portion forming surface 12A including the processed portion and the periphery thereof, or the entire surface of the recessed portion forming surface 12A. There may be. Alternatively, an ion wind generator may be provided outside the optical disk drive DD so that the ion wind is applied to the recess forming surface 12A via a supply pipe or the like.

  The optical disc drive DD as described above is loaded with the substrate 100 with the recess forming surface 12A facing downward (in FIG. 5, the recess forming surface 12A is directed in the direction of gravity). Then, according to the material of the photoresist layer 12, laser light is irradiated to the photoresist layer 12 with an output suitable for deforming it as an initial value. Further, a pulse signal or a continuous signal is input to the laser light source 51 so that this irradiation pattern matches the pattern of the concave portion 15 to be formed such as dots or grooves exemplified in FIGS.

  As shown in FIG. 3B, the duty ratio (light emission time τ / period T) of the laser light emitted at a predetermined period T is the duty ratio (laser beam scanning direction) of the recess 15 that is actually formed. The length d / pitch P of the recesses 15 in FIG. Here, the laser beam shown in a circle in FIG. 3A contributes to the formation of the elliptical recess 15 by moving at a predetermined speed during the emission time τ.

  For example, when the length d of the recess 15 is 50 when the pitch P of the recess 15 is 100, the laser beam may be irradiated with a duty ratio lower than 50%. . In this case, the upper limit value of the duty ratio of the laser beam is preferably less than 50%, more preferably less than 40%, and further preferably less than 35%. Furthermore, the lower limit is preferably 1% or more, more preferably 5% or more, and further preferably 10% or more. As described above, by setting the duty ratio, it is possible to accurately form the recesses 15 having a specified pitch.

  Further, by using a focusing technique similar to that of a known optical disc drive, for example, an astigmatism method, even if the light emitting unit 11 is wavy or warped, it can be easily condensed on the surface of the light emitting surface 18. Is possible.

  In this manner, as shown in FIG. 4C, the laser beam is condensed and irradiated by the optical system 50 of the optical disc drive DD from the recess forming surface 12A (light emitting surface 18) side (lower side). Then, as in the case of recording information on the optical recording disk, the concave portion 15 is formed on the entire light emitting surface 18 by moving the optical system 50 in the radial direction while rotating the light emitting portion 11. At this time, ion wind is applied from the ion wind generator 60 to the recess forming surface 12A.

  In addition, during or after the formation of the recess 15, a standard plate is loaded into the optical disc drive DD, and the reference light of the standard plate is irradiated with laser light (inspection light) from the optical system 50 and reflected by the reference surface. Is detected by the detector 57. After that, when the substrate 100 is loaded into the optical disk drive DD and the amount of return light is a predetermined amount, the controller CA causes the laser light source 51 to emit a laser beam that maintains the output to form the recess 15. On the other hand, when the amount of return light is less than the predetermined amount, the controller CA causes the laser light source 51 to emit a laser beam having a high output to form the recess 15.

The processing conditions for forming the recess 15 are as follows.
From the viewpoint of processing accuracy, the lower limit of the numerical aperture NA of the optical system 50 is preferably 0.4 or more, more preferably 0.5 or more, and still more preferably 0.6 or more. Further, the upper limit of the numerical aperture NA is preferably 2 or less, more preferably 1 or less, and even more preferably 0.9 or less, from the viewpoint of tolerance to angular variation.

  The wavelengths of the optical system 50 are, for example, 405 ± 30 nm, 532 ± 30 nm, 650 ± 30 nm, and 780 ± 30 nm. This is because these wavelengths are easy to obtain a large output. A shorter wavelength is preferable because fine processing can be performed.

  From the viewpoint of processing time, the lower limit of the output of the optical system 50 is 0.1 mW or more, preferably 1 mW or more, more preferably 5 mW or more, and further preferably 20 mW or more. The upper limit of the output of the optical system 50 is 1000 mW or less, preferably 500 mW or less, more preferably 200 mW or less, from the viewpoint of the durability of the member.

  The lower limit of the linear velocity for moving the optical system 50 relative to the photoresist layer 12 is 0.1 m / s or more, preferably 1 m / s or more, more preferably from the viewpoint of processing time and processing accuracy. 5 m / s or more, more preferably 20 m / s or more. Further, the upper limit of the linear velocity is 500 m / s or less, preferably 200 m / s or less, more preferably 100 m / s or less, and further preferably 50 m / s or less, from the viewpoint of machining accuracy.

  As an example of a specific optical disk drive DD including the optical system 50, for example, DDU1000 manufactured by Pulstec Industrial Co., Ltd. can be used.

  After the recess 15 is formed by the optical disk drive DD as described above, although not shown, individual LED elements 10 can be manufactured by cutting the substrate 100, and the LED elements 10 are fixed to the case 20 and necessary. The LED package 1 shown in FIG. 1 can be manufactured by performing simple wiring.

  After the recess 15 is formed on the recess forming surface 12A (the photoresist layer 12 and the barrier layer 13) as described above, a cleaning process is performed. Specifically, when the amount of return light detected in the detection step is smaller than a predetermined amount, the third lens 55 that is the objective lens of the optical system 50 is cleaned after the recess 15 is formed. The cleaning of the third lens 55 includes the method of blowing out the foreign matter by blowing gas vigorously, the method of removing the foreign matter with a soft brush, the method of removing the foreign matter with a cleaning agent such as alcohol, and the like. Depending on the material and material, etc., it is done in a way that does not damage the lens.

  The method of irradiating the inspection light and detecting the return light amount can be performed by the same method as the output adjustment method of the laser light source 51 by the control device CA described above. It should be noted that the predetermined amount of the return light amount that is a reference for whether or not to perform the cleaning step and the predetermined amount of the return light amount that is a reference for whether or not to adjust the output of the laser light in the output adjustment step are the same value (or Range) or different values (or ranges). Further, the cleaning may be performed by a machine or may be performed manually.

  Further, the cleaning of the third lens 55 may be performed periodically regardless of whether or not the return light amount is detected. The frequency of cleaning can be appropriately set according to the amount of foreign matter generated from the photoresist layer 12, the installation environment of the optical disk drive DD, and the like. For example, it may be set by the number of processed substrates 100 such as every 1000, every 100, every 10 and every 1 month, every month, every week, every day, every hour, etc. As described above, the operation time of the optical disk drive DD may be set.

According to the above, the following effects can be obtained in the present embodiment.
Since the concave portion 15 is formed with the concave portion forming surface 12A directed in the direction of gravity, the foreign matter generated when the concave portion 15 is formed by irradiating the condensed light onto the photoresist layer 12 can be dropped. Thereby, since it can suppress that a foreign material remains in the recessed part 15 and its circumference | surroundings, a favorable uneven | corrugated shape can be formed.

  Since the concave portion 15 is formed while applying ion air to the concave portion forming surface 12A, the photoresist layer 12 can be charged. As a result, the concave portion 15 and its surroundings and the foreign matter are charged to the same charge, so that the foreign matter can be positively suppressed from adhering to the concave portion 15 and its surroundings by the electrostatic repulsive force.

  During or after the formation of the recess 15, the reference surface is irradiated with inspection light from the optical system 50, and the light amount (return light amount) of the inspection light reflected from the reference surface is detected so that the light amount becomes a predetermined amount. Since the output of the laser light source 51 is adjusted, the concave portion 15 can always be formed with a predetermined amount of light even if foreign matter adheres to the third lens 55.

  Since the third lens 55 that is the objective lens of the optical system 50 is cleaned after the formation of the concave portion 15, the next time the concave portion 15 is formed, it is possible to irradiate the laser light with no foreign matter on the third lens 55. A favorable uneven shape can be formed. Further, since the amount of return light is smaller than the predetermined amount or is periodically cleaned, the possibility of scratches on the objective lens can be reduced.

  In the LED package 1 formed as described above, the refractive index gradually changes macroscopically in the vicinity of the light emitting surface 18 due to the fine uneven shape formed on the light emitting surface 18 and is emitted from the light emitting surface 18. Reflection of light on the inner surface of the light emitting surface 18 is suppressed. Thereby, the luminous efficiency of the LED package 1 is improved.

  Further, by using the photoresist layer 12 capable of changing the heat mode shape, the concave portion 15 can be formed only by irradiating the condensed laser beam, and the formation of the photoresist layer 12 can be carried out in large quantities by coating or the like. Therefore, the concave portion 15 can be formed quickly and inexpensively. In addition, by using a known focusing technique, it is possible to easily manufacture the recess 15 even if the material has undulations.

  Such processes include, for example, a method using a photoresist material that requires a development process, a method using a complicated process such as baking, exposure, baking, and etching by applying a material, as in the past. It is extremely simple when compared. Therefore, it is possible to easily improve the light emission efficiency by forming a fine uneven shape on the light emitting surface of the light emitting element.

[Second Embodiment]
Next, a method for manufacturing an optical element according to the second embodiment of the present invention will be described. FIG. 6 is a diagram of an optical element according to the second embodiment.
The optical element 10A is a member having a high light transmittance, and is used in close contact with or adhered to the light emitting surface of the light emitting element. For example, the LED package 1 illustrated in the first embodiment is used by being attached to the surface of the light emitting surface 18 or the surface of a fluorescent tube.

As shown in FIG. 6, in the optical element 10A, a photoresist layer 12 and a barrier layer 13 similar to those of the first embodiment are formed on a transparent support 11A, and a recess 15 is further formed.
The support 11A only needs to have sufficient transparency (for example, a transmittance of about 80% or more) with respect to the light emitted from the light-emitting element. For example, a resin such as polycarbonate or a glass material is used.

  When the recess 15 is formed, it can be formed by converging the laser beam and irradiating it in a pulsed manner in the same manner as in the first embodiment while moving the support 11A with the photoresist layer 12 facing downward. . At this time, as shown in FIG. 6, the laser beam may be irradiated from the support 11A side (the side opposite to the photoresist layer 12). Thus, when the laser beam is irradiated from the side opposite to the photoresist layer 12, there is an effect that the foreign matter generated when forming the recess 15 does not fall on the objective lens of the optical system 50A.

  The optical element 10A thus configured can improve the light emission efficiency of these light emitting elements by being attached to the surface of the light emitting surface 18 of the LED package 1 or the surface of the fluorescent tube.

[Third Embodiment]
Next, a method for manufacturing a light emitting device according to the third embodiment of the invention will be described. 7A to 7C are diagrams showing a manufacturing process of the LED element according to the third embodiment.

  In the manufacturing method of the LED element 10 according to the third embodiment, first, the photoresist layer 12 and the barrier as shown in FIG. 7A are obtained by performing the same steps as in the first embodiment (see FIG. 4). A recess 15 is formed in the layer 13. Thereafter, etching is performed using the photoresist layer 12 and the barrier layer 13 in which the recess 15 is formed as a mask, so that the hole 16 corresponding to the recess 15 is formed in the light emitting surface 18 as shown in FIG. Form. Then, as shown in FIG. 7C, by removing the photoresist layer 12 and the barrier layer 13 with a predetermined stripping solution or the like, the light emitting surface 18 formed in the concavo-convex shape is exposed.

  Here, as the etching, various etching methods such as wet etching and dry etching can be adopted, but it is preferable to adopt RIE that allows high patterning of etching gas and fine patterning. Moreover, as a removal method of the photoresist layer 12 and the barrier layer 13, various methods, such as a dry method and a wet method, are employable.

  As specific examples of the etching method and the removing method, for example, the material of the layer including the light emitting surface 18 of the light emitting unit 11 is glass, the material of the photoresist layer 12 is a pigment, and the material of the barrier layer 13 is In the case of an inorganic material layer, RIE using SF6 as an etching gas can be employed, and a wet removal method using ethanol as a stripping solution can be employed. Here, the layer including the light emitting surface is any layer that forms an interface with an external environment such as a gas such as air or a liquid such as water after the LED element 10 is manufactured. Such a layer may be used.

  As described above, according to the manufacturing method according to the third embodiment, since the unevenness is formed on the surface (light emitting surface 18) of the LED element 10 itself, the difference in refractive index between the LED element 10 and the photoresist layer 12 is a concern. Therefore, it is possible to easily design the uneven shape. In the present embodiment, a plurality of recesses 15 are formed in the photoresist layer 12 previously formed on the surface of the LED element 10 by a focusing technique or the like, so that the mask is accurately adhered to the surface of the LED element 10. It will be set. Therefore, in this embodiment, the problem that the mask cannot be brought into close contact due to warping of the surface of the LED element 10 does not occur as in the prior art, and the uneven shape can be easily formed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented.
In the embodiment, the LED element 10 is shown as an example of the light emitting element. However, the light emitting element is not limited to the LED element. For example, a plasma display element, a laser, an SED element, a fluorescent tube, an EL element, and the like emit light. If it is, it will not specifically limit.

  In each of the above embodiments, the method for forming a recess according to the present invention is applied to a method for manufacturing a light emitting element or an optical element. However, the present invention is not limited to this, and the present invention may be applied to a method for manufacturing an uneven product. . That is, as shown in FIGS. 8A and 8B, a hole 16 is formed as information on a substrate (base) 210 made of an inorganic material, and a protective layer 220 is provided on the hole 16 side of the substrate 210. Thus, the present invention can also be applied to a method of manufacturing an optical reading information recording medium (optical disc 200) as an example of a concavo-convex product.

  Specifically, by the same method as that shown in FIG. 4, the photoresist layer 12 and the barrier layer 13 are formed on the substrate 210, the surface on which the photoresist layer 12 and the like are formed faces downward, and the collected light. To form the recess 15. Thereafter, holes 16 corresponding to the recesses 15 are formed in the substrate 210 by using the photoresist layer 12 and the like as a mask by the same method as shown in FIG. According to the above, the hole 16 can be satisfactorily formed in the substrate 210.

Note that the material of the substrate 210 is preferably a material containing Si or Al. For example, Si, SiO ₂ , Al ₂ O ₃ or the like is preferable. The protective layer 220 is made of an inorganic material such as an inorganic oxide such as SiO ₂ , an inorganic nitride such as Si ₃ N _4, or an organic material such as a UV curable resin. Or they can be used in combination. However, from the viewpoint of extending the life of the optical disc 200, the protective layer 220 is preferably formed of an inorganic material.
Further, the uneven product is not limited to the optical disc, and may be, for example, a semiconductor, EL (electroluminescence), liquid crystal, SED (surface electric field display), mold, or the like.

  In the above embodiment, the photoresist layer 12 is provided directly on the light emitting surface of the light emitting element or the optical element or on the surface of the substrate 210 constituting the optical disc 200. However, the photoresist is interposed between the light emitting surface or the surface via another material. A layer 12 may be provided. In addition, when a protective layer or lens is provided on the surface of an LED element made of a semiconductor, the surface of the protective layer or lens (interface with air) becomes a light emitting surface. The resist layer 12 and the recess 15 may be provided.

  In the above embodiment, the laser beam is used to form the recess 15, but it may not be a monochromatic beam such as a laser beam as long as the laser beam can be condensed to a required size.

  In order to obtain a minimum processed shape, it is desirable that the diameter of the concave shape formed by the laser light irradiation for a short time is shorter than the wavelength of the laser light. In other words, it is preferable to reduce the spot diameter of the laser beam to be small so as to satisfy the above-described relationship.

  Further, when the concave portion 15 is larger than the minimum processed shape (hereinafter referred to as “laser spot”), the concave portion 15 may be formed by connecting the laser spots. Here, when the heat mode type photoresist layer 12 is irradiated with laser light, only the portion of the irradiated portion where the temperature becomes the transition temperature changes. That is, since the laser beam has the strongest light intensity near the center and gradually decreases toward the outside, a fine hole (laser spot) having a diameter smaller than the laser beam spot diameter is formed in the photoresist layer 12. It is possible to do. And when forming the recessed part 15 by making such a fine hole continue, the shape precision of the recessed part 15 can be improved. By the way, if it is a material that requires development, the reaction occurs in all the portions irradiated with the laser beam, so the hole (laser spot) formed by one laser beam is large, and the shape accuracy is a heat mode type material. It is worse than Therefore, it is preferable to use a heat mode type material as in the present invention.

  In the above embodiment, the barrier layer 13 is formed on the photoresist layer 12, but the present invention is not limited to this, and the barrier layer 13 may not be provided. In particular, when the photoresist layer 12 is used as an etching mask as in the third embodiment or the embodiment shown in FIG. 8, it is preferable that the barrier layer 13 is not provided.

  In the first embodiment, the example in which the substrate 100 in which the hole is not formed in the center is held by the plurality of arms 32 of the cage 30 has been described. However, the method for holding the substrate 100 in which the hole is not formed in the center is described. Is not limited to this. For example, it may be held by vacuum suction or electrostatic suction. In the case of a substrate having a hole formed in the center, the hole in the substrate may be held from below by a rotating shaft (spindle) of a motor, as in the case of an optical disk loaded in a conventionally known optical disk drive. .

  In the first embodiment, the motor 40 is disposed at a position above the substrate 100, but the present invention is not limited to this. That is, the motor may be arranged at a position below the substrate as in a conventionally known optical disk drive.

  In the above-described embodiment, an example in which a standard plate provided separately from the photoresist layer 12 set in the optical disc drive DD is employed as an example of the reference surface, but the reference surface of the present invention is limited to this. It is not a thing. For example, as another example of the reference surface provided separately from the photoresist layer, a region (surface) having a known reflectance provided in the optical disc drive DD, a standard plate, or the like may be employed. Further, the reference surface of the present invention may be a reference surface provided on the photoresist layer 12 (recessed surface 12A) of the substrate 100. For example, in the recess forming surface 12A, a region (such as a region where no recess is formed) whose reflectance is known or constant before, during and after the formation of the recess 15 can be used as the reference surface. According to these, since it is not necessary to replace the substrate 100 and the reference surface (standard plate) as in the above-described embodiment, the reference surface is irradiated with the inspection light at a predetermined timing while forming the recess on the recess forming surface. Then, the output of the light source can be adjusted by detecting the amount of return light. Therefore, the concave portion can always be formed with the optimum light amount, so that a better concave and convex shape can be formed.

  In the first embodiment, the configuration in which the detector 57 of the optical system 50 is used to detect the amount of return light is illustrated, but the present invention is not limited to this, and for example, an external sensor provided separately from the optical system 50 A configuration may be adopted in which the amount of return light is detected by a known reflectance measuring device or the like and output to the control device CA.

  In the first embodiment, the amount of inspection light reflected from the reference surface is detected. However, the present invention is not limited to this. For example, the amount of inspection light diffracted from the reference surface is detected. The output of the light source may be adjusted so that

  In the first embodiment, the example in which the half mirror 54 is used to guide the inspection light reflected from the reference surface to the detector 57 has been described. However, the present invention is not limited to this, and for example, a polarizing beam splitter is used. May be. In this case, an optical component such as a known wave plate can be appropriately provided.

  In the third embodiment, the hole 16 is formed on the surface of the LED element 10, but the present invention is not limited to this, and the surface of the optical element 10A (the surface of the support 11A) as in the second embodiment is not limited thereto. The hole may be formed using the photoresist layer 12 or the like as an etching mask.

  In the third embodiment and the embodiment shown in FIG. 8, the photoresist layer 12 and the like are directly formed on the surface (the light emitting surface 18 or the surface of the substrate 210) where the hole 16 is formed as an etching mask. It is not limited to this. For example, when the photoresist layer 12 or the like is easily scraped off by the etching gas, as shown in FIG. 9A, the mask layer that can be etched by the etching gas that hardly affects the photoresist layer 12 or the like. 17 may be provided between the light emitting surface 18 and the photoresist layer 12. Although FIG. 9 shows a mode in which the hole 16 is formed on the light emitting surface 18, the mask layer 17 can be similarly provided when the hole 16 is formed on the surface of the substrate 210.

  According to this, first, as in the first embodiment, the recess 15 is formed in the photoresist layer 12 and the barrier layer 13 with laser light. Next, as shown in FIG. 9B, the through hole 17 a corresponding to the recess 15 is formed in the mask layer 17 by etching the mask layer 17 with the first etching gas. Here, as the first etching gas, a gas that does not scrape the photoresist layer 12 and the barrier layer 13 is selected. Therefore, the mask layer 17 is formed using the photoresist layer 12 and the barrier layer 13 as a mask. Etched.

  Thereafter, as shown in FIG. 9C, the hole 16 corresponding to the recess 15 is formed on the light emitting surface 18 by etching the layer including the light emitting surface 18 with the second etching gas. At this time, the photoresist layer 12 and the barrier layer 13 are etched and disappeared immediately by the second etching gas, but the light emitting surface 18 is satisfactorily etched using the mask layer 17 as a mask. After that, as shown in FIG. 9D, the mask layer 17 is removed with a predetermined stripping solution or the like, so that the light emitting surface 18 formed in an uneven shape is exposed.

Here, as a specific example of the form shown in FIG. 9, for example, the material of the layer including the light emitting surface 18 of the light emitting unit 11 is sapphire, the material of the photoresist layer 12 is a pigment, and the material of the barrier layer 13. Is an inorganic layer, Si-containing Bi-Layer photoresist manufactured by Tokyo Ohka Kogyo Co., Ltd. is used as the mask layer 17, SF 6 is used as the first etching gas, and Cl _{2 is used} as the second etching gas. Should be adopted.

Next, an example in which the effect of the present invention has been confirmed will be described.
[Example 1]
A dye layer (photoresist layer) having a thickness of 100 nm was formed on a disk-shaped substrate. Details of the substrate and the dye layer are as follows.

・ Substrate material Silicon thickness 0.5mm
Outer diameter 101.6mm (4 inches)
Inner diameter 15mm

・ Dye layer (photoresist layer)
2 g of a dye material having the following chemical formula was dissolved in 100 ml of a TFP (tetrafluoropropanol) solvent and spin-coated. At the time of spin coating, the coating liquid was dispensed on the inner periphery of the substrate at a coating start rotation speed of 500 rpm and a coating end rotation speed of 1000 rpm, and the rotation was gradually increased to 2200 rpm. The refractive index n of the dye material is 1.986, and the extinction coefficient k is 0.0418.

The surface of the substrate on the dye layer side is irradiated with a laser beam in a radius range of 30 to 31 mm under the following conditions, and fine concave portions are pitched by 10 μm in the radial direction and 0.3 μm in the circumferential direction. Formed with pitch.
The conditions for forming the recess are as follows.
Initial value of laser output 2.5mW
Line speed 5m / s
Recording signal 5 MHz rectangular wave

  In Example A, DDU1000 manufactured by Pulstec Industrial Co., Ltd. (wavelength: 405 nm, NA: 0.85. A 0.1 mm thick aberration correction plate is installed in the head) with the substrate facing the photoresist layer side in the direction of gravity. Then, a laser beam was irradiated from below while applying an ion wind to form a fine recess.

  In Example B, the substrate was set in the DDU 1000 in the same manner as in Example A, and a fine recess was formed by irradiating laser light from below without applying an ion wind.

  As a comparative example, the substrate is set in NEO1000 (wavelength 405 nm, NA 0.85) manufactured by Pulstec Industrial Co., Ltd. with the surface on the side of the photoresist layer facing upward, and irradiated with laser light from above while applying ion wind. And formed a fine recess.

  The surface of the substrate on which the recesses were formed as described above was observed with an SEM (scanning electron microscope). The results are shown in Table 1. Here, in “Substrate surface state” in Table 1, “◎” indicates that the proportion of solids in the SEM visual field area is less than 1%, and “◯” indicates the SEM visual field area. The percentage of solids indicates less than 5%, and “x” indicates that the percentage of solids in the SEM viewing area is 5% or more.

  As shown in Table 1, in Example A, the ratio of the solid matter occupying the field of view of the SEM was less than 1%, and almost no solid matter was confirmed on the substrate (）). In Example B, the proportion of solids in the SEM viewing area was 1% or more and less than 5%, and the adhesion of solids on the substrate was slightly confirmed as compared to Example A (◯ ). On the other hand, in the comparative example, the ratio of the solid matter occupying the field area of the SEM was 5% or more, and adhesion of the solid part on the substrate was confirmed (×).

  From the above, it was confirmed that by forming the concave portion with the surface on the side of the photoresist layer facing downward, adhesion of solid matter to the substrate was suppressed, and a good concavo-convex shape was formed on the substrate. Moreover, it was confirmed that by applying an ionic wind during the formation of the recesses, the solid matter was further prevented from adhering to the substrate, and a better uneven shape was formed on the substrate.

[Example 2]
A substrate (silicon substrate) to which nothing was applied was prepared as a standard plate. This standard plate is set on DDU1000 (wavelength 405 nm, NA 0.85. A 0.1 mm thick aberration correction plate is installed on the head) made by Pulstec Industrial Co., Ltd. It was measured.

  Next, formation of recesses was performed on 50 substrates similar to those in Example 1. Specifically, each substrate is set on the DDU 1000 with the surface of the photoresist layer facing the gravitational direction one by one, and a laser beam is irradiated from below to the radius range of 30 to 31 mm, and the pitch is 10 μm in the radial direction. The formation of recesses with a diameter of 150 nm at a pitch of 0.3 μm in the circumferential direction was performed. The initial value of the laser output, the linear velocity, and the recording signal are the same as in the first embodiment. At this time, the DDU 1000 was installed in a room that was not a clean room, and the lid was opened during the formation of the recess.

After forming recesses on 50 substrates, the standard plate was set on the DDU 1000 again, and the amount of return light was measured while applying automatic focus servo.
Thereafter, formation of a recess was performed on the same substrate as in Example 1 under the following conditions. The other conditions are the same as when concave portions are formed on 50 substrates.

  In Example C, a substrate similar to that in Example 1 was set on the DDU 1000 with the surface on the photoresist layer side facing the direction of gravity, and the laser beam output was increased by 10% to form a recess.

  In Example D, the objective lens was first cleaned with air blow and brush, then the standard plate was set and the amount of return light was measured while applying autofocus servo. Thereafter, a substrate similar to that in Example 1 was set in the DDU 1000 with the surface on the photoresist layer side facing the direction of gravity, and formation of a recess was performed without changing the output of the laser beam. Note that “the laser beam output is not changed” means that the concave portion is formed with the same output as when the concave portion is formed on the 50 substrates.

  As a comparative example, the objective lens is not cleaned, and the same substrate as in Example 1 is set on the DDU 1000 with the surface on the photoresist layer side in the direction of gravity, and a recess is formed without changing the output of the laser beam. Executed.

  And the diameter of the recessed part formed in each board | substrate was measured by the well-known method. The results are shown in Table 2. Note that the amount of return light is “9” when the amount of return light measured before forming the recess is “10”, and the amount of return light measured after forming the recess on 50 substrates is “9”, measured after cleaning the objective lens. The returned light quantity was “10”.

  As shown in Table 2, in Examples C and D, the diameter of the recess was 150 nm. On the other hand, in the comparative example, the diameter of the recess was as small as 130 nm. That is, with the recess forming method of the comparative example, a desired recess dimension could not be obtained.

  From the above, after irradiating the inspection surface with the inspection light and detecting the amount of inspection light reflected from the reference surface, adjusting (higher) the output of the light source (laser light) or cleaning the objective lens, It was confirmed that a better uneven shape was formed on the substrate.

(A) is a figure of an LED package, (b) is an enlarged view of (a). (A) is a figure of an example which looked at the light emission surface planarly, (b) is a figure of another example. (A) is a figure explaining the relationship between the diameter of a recessed part, and a pitch, (b) is a figure explaining the relationship between the light emission time of a laser beam, and a period. (A)-(c) is a figure which shows the manufacturing process of an LED package. It is a figure which shows the optical disk drive which forms a recessed part in a photoresist layer etc. FIG. It is a figure of the optical element which concerns on 2nd Embodiment. (A)-(c) is a figure which shows the manufacturing process of the LED element which concerns on 3rd Embodiment. It is the perspective view (a) and sectional drawing (b) which show the optical disk manufactured by the manufacturing method containing the recessed part formation method of this invention. (A)-(d) is a figure which shows the form which changed the manufacturing process of the LED element which concerns on 3rd Embodiment partially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED package 10 LED element 10A Optical element 11 Light emission part 11A Support body 12 Photoresist layer 12A Concave formation surface 15 Concave part 16 Hole part 18 Light emission surface 30 Holder 40 Motor 50 Optical system 51 Laser light source 55 3rd lens 57 Detector 60 Ion Wind generator 200 Optical disk 210 Substrate CA controller DD Optical disk drive

Claims (9)

A recess forming method for forming a plurality of recesses in the photoresist layer by irradiating light collected from an optical system configured to include a light source on the photoresist layer capable of heat mode shape change,
A method of forming a recess, wherein the recess forming surface of the photoresist layer is directed in the direction of gravity and light is irradiated from the opposite side of the recess forming surface to form a recess in the recess forming surface . A recess forming method for forming a plurality of recesses in the photoresist layer by irradiating light collected from an optical system configured to include a light source on the photoresist layer capable of heat mode shape change,
Forming a recess with the recess forming surface of the photoresist layer directed in the direction of gravity;
During or after the formation of the recess in the photoresist layer,
An inspection light irradiation step of irradiating inspection light from the optical system to a reference surface provided on the photoresist layer or a reference surface provided separately from the photoresist layer;
A detection step of detecting the amount of inspection light reflected or diffracted from the reference surface;
If detected the light amount is smaller than the predetermined amount, the recess forming how to characterized in that and a cleaning step for cleaning the optical system of the objective lens after the formation of the recess to the photoresist layer. Recess forming method according to claim 1 or claim 2, characterized in that the recess while applying an ion wind in the recess formation surface of the photoresist layer. During or after the formation of the recess in the photoresist layer,
An inspection light irradiation step of irradiating inspection light from the optical system to a reference surface provided on the photoresist layer or a reference surface provided separately from the photoresist layer;
A detection step of detecting the amount of inspection light reflected or diffracted from the reference surface;
The method according to claim 2 , further comprising: an output adjustment step of adjusting an output of the light source so that the light amount becomes a predetermined amount based on the detected light amount. A method for producing an uneven product having unevenness on the surface of a substrate,
Forming a photoresist layer capable of heat mode shape change on the surface of the substrate;
A step of forming a plurality of recesses in the photoresist layer by the recess forming method according to any one of claims 1 to 4,
Forming a hole corresponding to the recess on the surface of the substrate by performing etching using a photoresist layer having a plurality of recesses as a mask. Production method. A method for manufacturing a light emitting device having a light emitter,
Forming a photoresist layer capable of heat mode shape change on the light emitting surface of the light emitter;
A method of manufacturing a light emitting device, comprising: forming a plurality of recesses in the photoresist layer by the recess forming method according to claim 1.   7. The light emitting device according to claim 6, wherein a hole corresponding to the concave portion is formed in the light emitting surface by etching using the photoresist layer having a plurality of concave portions as a mask. Method. A method of manufacturing an optical element that improves the luminous efficiency of the light emitting element by being attached to the light emitting surface of the light emitting element,
Forming a photoresist layer capable of changing the shape of the heat mode on the surface of the support capable of transmitting light emitted from the light-emitting element;
A method for manufacturing an optical element, comprising: forming a plurality of recesses in the photoresist layer by the recess forming method according to any one of claims 1 to 4.   9. The optical element according to claim 8, wherein a hole corresponding to the recess is formed in the surface of the support by performing etching using the photoresist layer having a plurality of recesses as a mask. Manufacturing method.

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