JP2013003542A - Optical element assembly, optical element, production method of optical element assembly, and production method of optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element assembly, in which chipping on a cut face, peeling of a resin or interfacial fracture of a substrate can be prevented even when a part where a resin and the substrate are laminated is cut.SOLUTION: The optical element assembly includes a metal oxide film 104 between a substrate 101 and a resin 102b of first and second resin layers 102, 103 having flexibility imparted thereto in a range not degrading reflow resistance, the metal oxide film having a low stress itself and a low film density. Upon cutting a part where the substrate 101 and the first and second resin layers 102, 103 overlap, chipping on a cut face or peeling of the first and second resin layers 102, 103 caused by a stress during cutting or interfacial fracture of the substrate 101 can be prevented, and dicing durability can be improved. As a result, in a subsequent reflow process, the first and second resin layers 102, 103 do not peel from the substrate 101, which enhances reliability of the optical element.

Description

  The present invention relates to an optical element assembly such as a wafer lens in which a resin layer including a plurality of optical element portions is formed on a substrate, an optical element obtained by dicing the optical element assembly into individual pieces, and those It relates to the manufacturing method.

  As a method of manufacturing optical elements such as photographing lenses, a certain amount of a resin material is supplied to the center of a mold having molding parts corresponding to a large number of lens parts and spread on a substrate, and then the resin material is cured and molded. There is known a method of manufacturing individual optical elements by dicing a lens assembly such as a wafer lens obtained by releasing the mold into individual pieces (see, for example, Patent Document 1). This method is advantageous for shortening the resin supply time and making the resin amount uniform for each lens. In addition, when a curable resin material is used, it is possible to cope with a reflow process, and it is possible to mount the electronic component together with the electronic component on the substrate in the reflow process.

  Here, the curable resin that can cope with the reflow process has high heat resistance and hardness, but on the other hand, it is brittle and has a property of being easily cured and contracted. Therefore, in the method of Patent Document 1, when the blade enters a portion where the resin and the substrate overlap when dicing the molded product, the cutting surface is chipped due to brittleness of the resin and is caused by stress at the time of cutting. There are cases where peeling of the resin or interfacial destruction of the substrate occurs. As a result, there is a risk that the appearance failure or performance deterioration of the optical element may occur in the subsequent reflow process or the like.

JP 2009-226638 A

  The present invention provides an optical element assembly that can prevent chipping of the cut surface, peeling of the resin, and interface destruction of the substrate even if the portion where the resin and the substrate overlap is cut, and by cutting the optical element assembly. It is an object to provide an optical element.

  Another object of the present invention is to provide an optical element assembly manufacturing method for manufacturing the above-described optical element assembly, and an optical element manufacturing method using the optical element assembly.

In order to solve the above problems, an optical element assembly according to the present invention includes a substrate, a metal oxide film provided on at least one surface of the substrate, and a plurality of metal oxide films provided on the metal oxide film and connected to each other by a resin. A loss tangent of the resin layer is 0.30 or more and 0.50 or less, and a film density of the metal oxide film is 1.5 g / cm ³ or more and 2.0 g / cm ³ or less. Here, the loss tangent is a ratio E ″ / E ′ between the storage elastic modulus E ′ and the loss elastic modulus E ″, and is represented by tan δ. The loss tangent is a physical property value indicating how much energy the material absorbs when the material deforms. The loss tangent tan δ of the resin correlates with the crosslink density of the resin and affects the flexibility and heat resistance of the resin. Specifically, the closer the loss tangent tan δ is to 0, the harder and brittle the resin becomes and the lower the flexibility, but the heat resistance improves. Conversely, the closer the loss tangent tan δ is to 1, the more flexible the resin is, but the more the heat resistance deteriorates. On the other hand, the film density of the metal oxide film correlates with the stress and hardness of the film. Specifically, the higher the film density, the greater the stress of the metal oxide film, which becomes harder and more brittle and less flexible, but the adhesion is improved. Conversely, as the film density is lower, the metal oxide film has lower stress and improved flexibility, but the adhesiveness deteriorates.

  The inventor sets the loss tangent tan δ of the resin within an appropriate range, and interposes a metal oxide film having an appropriate film density between the resin and the substrate, so that either the resin or the metal oxide film can be used. It is found that only one of them has flexibility, and can achieve the effect of avoiding chipping at the time of dicing, peeling of the resin, and interface destruction of the substrate while maintaining the heat resistance of the resin, The present invention has been reached.

  According to the optical element assembly described above, the internal stress of the resin can be relaxed between the substrate and the resin layer that has been given flexibility by reducing the crosslink density within a range in which the reflow resistance is not deteriorated. A metal oxide film having a film density is provided. This prevents the occurrence of chipping (chips) on the cut surface and peeling of the resin due to stress at the time of cutting and interfacial breakage of the substrate when cutting the portion where the substrate and the resin overlap. Can be improved. As a result, in the subsequent reflow process, the resin does not peel from the substrate, and the reliability of the optical element can be improved. In other words, by ensuring the flexibility of the resin and the flexibility of the metal oxide film that is the base of the resin, the resin does not peel even when the optical element is exposed to a high temperature such as a reflow process, and the optical element Reliability can be improved.

  In a specific aspect or viewpoint of the present invention, in the optical element assembly, the storage elastic modulus of the resin layer at 25 ° C. is 2 GPa or more and 3 GPa or less. Here, the storage elastic modulus is a physical property value indicating the ability of the material to retain the stress stored therein. Resins having a storage elastic modulus satisfying the above range are relatively soft and can further improve the dicing resistance.

  In another aspect of the present invention, the compressive stress of the metal oxide film is 90 MPa or more and 150 MPa or less. Here, the compressive stress is a physical property value indicating a stress generated when a compressive load is applied to the material. When the compressive stress satisfies the above range, the internal stress of the resin layer can be relaxed at the time of cutting, and the dicing resistance can be further improved.

  In still another aspect of the present invention, the thickness of the portion of the resin layer to be cut is 100 μm or less. In this case, the dicing resistance can be further improved.

  In still another aspect of the present invention, the metal oxide film is one of an infrared reflection film and an antireflection film.

  In still another aspect of the present invention, the resin layer is formed on the entire surface of at least one surface of the substrate. In this case, the dicing resistance and the reliability of the optical element can be improved even if a center dropping process is adopted in which a resin is supplied to the center of the substrate or mold that can shorten the lens production time.

  In order to solve the above-mentioned problems, the optical element according to the present invention is obtained by dicing the above-described optical element assembly into a plurality of lens parts.

  According to the above optical element, the optical element assembly has a metal oxide film between the substrate and the resin layer, and the resin layer and the metal oxide film have flexibility, so that the chip is formed on the cut surface of the optical element. Or peeling of the resin can be prevented. As a result, even if the cut optical element is exposed to a high temperature as in the reflow process, the resin does not peel off, and the reliability of the optical element can be improved.

In order to solve the above problems, a method for manufacturing an optical element assembly according to the present invention includes a film forming step of forming a metal oxide film on at least one surface of a substrate, and a metal oxide film on the metal oxide film after the film forming step. A resin molding step of forming a resin layer having a plurality of lens portions connected to each other by a resin, the loss tangent of the resin layer is not less than 0.30 and not more than 0.50, and the film density of the metal oxide film is 1 .5g / cm ³ or more 2.0g / cm ³ or less.

  According to the method for manufacturing an optical element assembly, a metal oxide film is provided between the substrate and the resin layer, and the resin layer and the metal oxide film have flexibility, so that the cut surface of the optical element can be chipped. It is possible to prevent the resin from peeling off. As a result, even if the cut optical element is exposed to a high temperature such as a reflow process, the resin does not peel off, and an optical element assembly that can improve the reliability of the optical element can be manufactured.

  In a specific aspect or viewpoint of the present invention, in the method for manufacturing an optical element assembly, the metal oxide film is formed by either vacuum evaporation or sputtering. In this case, the film density of the metal oxide film can be formed in the above range. Thereby, a softness | flexibility can be provided to a metal oxide film.

  In order to solve the above-described problems, an optical element manufacturing method according to the present invention cuts a substrate and a resin layer for each of a plurality of lens portions of the optical element assembly obtained by the above-described optical element assembly manufacturing method. A cutting process is provided.

  According to the method for producing an optical element, a metal oxide film is provided between the substrate of the optical element assembly and the resin layer, and the resin layer and the metal oxide film have flexibility, so that the cut surface of the optical element is obtained. It is possible to prevent chipping, resin peeling, and the like from occurring. As a result, even if the cut optical element is exposed to a high temperature as in the reflow process, the resin does not peel off, and an optical element that can improve the reliability of the optical element can be manufactured.

(A) is sectional drawing of a compound lens, (B) is a top view of a wafer lens, (C) is AA arrow sectional drawing of the wafer lens shown to (A). (A) is a perspective view of the master type | mold used for manufacture of the wafer lens of 1st Embodiment, and a compound lens, (B) is a perspective view of a submaster type | mold. (A)-(F) is a figure for demonstrating the manufacturing process of a wafer lens and a compound lens. It is a flowchart for demonstrating the manufacturing process of a wafer lens and a compound lens. It is a figure for demonstrating the dicing process among the manufacturing processes of a compound lens.

  With reference to drawings, the compound lens manufactured by the manufacturing method of the optical element which concerns on one Embodiment of this invention is demonstrated.

A) Compound Lens As shown in FIG. 1A, the compound lens 200 includes a first lens element 11, a second lens element 12, a flat plate portion 13 sandwiched therebetween, and a metal oxide film 104. And a diaphragm 105. The flat plate portion 13 is a portion obtained by cutting a substrate 101 of a wafer lens 100 described later along a cut line DX (see FIGS. 1B and 5). The compound lens 200 has a rectangular outer shape in plan view.

  The first lens element 11 is made of resin and is formed on one surface 101 a of the flat plate portion 13. The first lens element 11 includes a first lens body 11a and a first flange portion 11b. The first lens body 11a is, for example, a convex aspherical lens part, and has a first optical surface 11d. The surrounding first flange portion 11b has a flat first flange surface 11g extending around the first optical surface 11d. The first flange surface 11g is disposed in parallel to the XY plane perpendicular to the optical axis OA.

  Similar to the first lens element 11, the second lens element 12 is made of resin and is formed on the other surface 101 b of the flat plate portion 13. The second lens element 12 has a second lens body 12a and a second flange portion 12b. The second lens body 12a is, for example, a concave aspherical lens part, and has a second optical surface 12d. The surrounding second flange portion 12b has a flat second flange surface 12g extending around the second optical surface 12d. The second flange surface 12g is disposed in parallel to the XY plane perpendicular to the optical axis OA.

  In the compound lens 200, the first and second lens elements 11 and 12 may have the same shape or different shapes. The compound lens 200 is obtained by cutting out the wafer lens 100 by dicing described later. The compound lens 200 is housed in, for example, a separately prepared holder, and is fixed to each other by bonding to an imaging circuit board as an imaging lens. The material of the composite lens 200, the metal oxide film 104, the stop 105, and the like will be described in detail below.

B) Wafer Lens B-1) Structure of Wafer Lens As shown in FIGS. 1 (B) and 1 (C), a wafer lens 100 that is an optical element assembly has a disc shape, and includes a substrate 101 and a first resin. It has a layer 102, a second resin layer 103, a metal oxide film 104, and a diaphragm 105.

  The substrate 101 of the wafer lens 100 is a circular flat plate and is made of glass. The outer diameter of the substrate 101 is substantially the same as the outer diameter of the first and second resin layers 102 and 103. The thickness of the substrate 101 is basically determined by optical specifications, but is such a thickness that the wafer lens 100 is not damaged when the wafer lens 100 is released.

  The first resin layer 102 is made of resin and is formed on one surface 101 a of the substrate 101. The first resin layer 102 has a circular outer shape in plan view. The first resin layer 102 has a large number of first lens elements 11 arranged two-dimensionally in the XY plane. These first lens elements 11 are integrally formed through a flat connecting portion 11c. The combined surface of each first lens element 11 and connecting portion 11c is a first molding surface 102a that is collectively molded by transfer. The outer periphery of the 1st flange part 11b among the 1st lens elements 11 is also the connection part 11c.

  The first resin layer 102 is made of a photocurable resin. The photocurable resin contains a photopolymerization initiator for initiating polymerization of the photocurable resin and a monofunctional or polyfunctional monomer for adjusting the viscosity. As the photocurable resin, one having a relatively small curing shrinkage rate is used. Specifically, for example, an epoxy resin or the like can be used. When using an epoxy resin, it can be cured by cationic polymerization or anionic polymerization of a photopolymerization initiator. As the monofunctional or polyfunctional monomer for adjusting the viscosity, for example, an epoxy monomer can be used. Specifically, monomers such as allyl glycidyl ether (monofunctional), neopentyl glycol diglycidyl ether (bifunctional), and trimethylpropane polyglycidyl ether (trifunctional) can be used. When the loss tangent tan δ is made small, the amount of trifunctional monomers is increased, and when the loss tangent tan δ is made large, these use ratios may be changed so as to increase the monofunctional monomer.

  Here, the loss tangent tan δ of the first resin layer 102 is 0.30 or more and 0.50 or less. Here, the loss tangent tan δ is expressed by a ratio E ″ / E ′ between the storage elastic modulus E ′ and the loss elastic modulus E ″. The loss tangent tan δ indicates how much energy the material absorbs as the material deforms. The loss tangent tan δ of the resin correlates with the crosslink density of the resin and affects the flexibility and heat resistance of the resin. Specifically, the closer the loss tangent tan δ is to 0, the harder and brittle the resin becomes and the lower the flexibility, but the heat resistance improves. Conversely, the closer the loss tangent tan δ is to 1, the more flexible the resin is, but the more the heat resistance deteriorates. The storage elastic modulus E ′ indicates the ability of the material to retain the stress stored therein, and the loss elastic modulus E ″ indicates the ability of the material to dissipate the stress stored therein as heat. 'And the loss elastic modulus E "can be calculated from the slope of the obtained graph by plotting the measured value of the viscoelasticity measuring device while changing the temperature while giving a shear strain of a predetermined frequency. Further, the storage elastic modulus at 25 ° C. of the first resin layer 102 is 2 GPa or more and 3 GPa or less. Thereby, the 1st resin layer 102 has the heat resistance which can endure the softness | flexibility and reflow process which a chipping and peeling of a cut surface do not arise. Here, the reflow process is a process of heating at a high temperature in order to mount an electronic component or the like on the wafer lens 100 or the compound lens 200 cut out from the wafer lens 100. The thickness of the cut portion of the first resin layer 102 is 100 μm or less, preferably 80 μm or less, and is relatively thinner than the thickness of the first flange portion 11 b of the first lens element 11.

  Similar to the first resin layer 102, the second resin layer 103 is made of resin and is formed on the other surface 101 b of the substrate 101. The second resin layer 103 has a circular outer shape in plan view. The second resin layer 103 has a number of second lens elements 12 arranged two-dimensionally in the XY plane. These second lens elements 12 are integrally molded through a flat connecting portion 12c. The combined surface of each second lens element 12 and connecting portion 12c is a second molding surface 103a that is collectively molded by transfer. The outer periphery of the second flange portion 12b of the second lens element 12 is also a connecting portion 12c. The second flange surface 12g is disposed in parallel to the XY plane perpendicular to the optical axis OA.

  The photocurable resin used for the second resin layer 103 is the same as the photocurable resin of the first resin layer 102. However, both the resin layers 102 and 103 do not need to be formed of the same photocurable resin, and can be formed of different photocurable resins.

In this embodiment, the metal oxide film 104 is an infrared reflecting film for reflecting infrared rays. The metal oxide film 104 is formed on the entire surface of the substrate 101 with a substantially uniform thickness and density. That is, the metal oxide film 104 is provided between the substrate 101 and the first resin layer 102 and between the substrate 101 and the second resin layer 103. The metal oxide film 104 is, for example, an interference filter, and is formed by alternately laminating, for example, Ta ₂ O ₅ , TiO ₂ or the like as a high refractive material and SiO ₂ or the like as a low refractive material. The metal oxide film 104 is formed by, for example, vacuum vapor deposition or sputtering. The thickness of the metal oxide film 104 is, for example, not less than 40 nm and not more than 60 nm. The film density of the metal oxide film 104 is 1.5 g / cm ³ or more and 2.0 g / cm ³ or less. The compressive stress of the metal oxide film 104 is 90 MPa to 150 MPa, preferably 100 MPa to 130 MPa. Thereby, the metal oxide film 104 has flexibility that can relieve internal stress of the resin of the first and second resin layers 102 and 103. It is thought that the pure glass outermost surface is made of high-density silicon oxide. However, when resin is molded on glass that is not surface-treated (deposited), internal stress at the time of curing is directly reflected, dicing and environment Cracks occur during testing. On the other hand, when a relatively low density metal oxide film is provided on the glass surface, this metal oxide film functions as a stress relaxation layer for the resin provided thereon, such as chipping or resin peeling during dicing. This is considered to suppress the occurrence of problems such as the above-mentioned problems and the deterioration of optical performance that occurs during reflow. The metal oxide film 104 has the function of an infrared reflecting film as long as it can relieve the internal stress of the first and second resin layers 102 and 103 and does not affect the optical performance of the lens. It does not have to be.

  The diaphragm 105 is provided between the metal oxide film 104 and the first resin layer 102 and between the metal oxide film 104 and the second resin layer 103. The diaphragm 105 includes a diaphragm main body 105a that is a diaphragm member and an opening 105b. The aperture body 105a is formed in a part of a region excluding the first and second lens bodies 11a and 12a on at least one of the surfaces 101a and 101b of the substrate 101. The aperture body 105a is disposed so as not to interfere with the first and second lens bodies 11a and 12a. Further, as shown in FIG. 1B, the aperture body 105a is formed in a planned cutting area AR1 of the wafer lens 100, that is, an area AR2 other than the dicing line DX. As a result, the portion to be cut AR1 of the wafer lens 100 is thinner than other regions. The opening 105b is substantially circular and is formed at a position corresponding to the first and second lens bodies 11a and 12a. The aperture body 105a is formed of a light-shielding metal film, a resist, a silicon film, a carbon film, or the like. Since the aperture 105 is not formed in the planned cutting portion AR1 of the wafer lens 100, the internal stress of the aperture 105 need not be considered. The diaphragm 105 may be provided only between one of the substrate 101 and the first resin layer 102 and between the substrate 101 and the second resin layer 103. Further, the diaphragm 105 may not be provided.

B-2) Photocurable Resin Hereinafter, an example of an epoxy resin among the photocurable resins used for forming the first and second resin layers 102 and 103 will be described.

  The epoxy resin is not particularly limited as long as it has an epoxy group and is polymerized and cured by light, and a cation generator, an anion generator, or the like can be used as a curing initiator. Epoxy resins are preferred in that they can be made into lenses with excellent molding accuracy because of their low cure shrinkage.

  Examples of the epoxy resin include novolak phenol type epoxy resin, biphenyl type epoxy resin, and dicyclopentadiene type epoxy resin. Examples include bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, 2,2′-bis (4-glycidyloxycyclohexyl) propane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, vinyl Cyclohexene dioxide, 2- (3,4-epoxycyclohexyl) -5,5-spiro- (3,4-epoxycyclohexane) -1,3-dioxane, bis (3,4-epoxycyclohexyl) adipate, 1,2 -What polymerized cyclopropane dicarboxylic acid bisglycidyl ester etc. can be mentioned.

B-3) Photopolymerization initiator Hereinafter, the details of the photopolymerization initiator (UV initiator) used for the first and second resin layers 102 and 103 will be described. The photopolymerization initiator is basically selected in combination with a photocurable resin. In the case of an epoxy resin, any photopolymerization initiator may be used as long as it has an absorption maximum at a wavelength in the ultraviolet region (400 nm or less) and generates a cation or an anion at the wavelength in the ultraviolet region. it can. In selecting the photopolymerization initiator, consideration is given so as not to lower the transmittance in the wavelength range of use of the wafer lens 100, and consideration is given so that the absorbance with respect to the curing light becomes appropriate.

  Photopolymerization initiators that generate cations include sulfonium salts, iodonium salts, diazonium salts, ferrocenium salts, diethylenetriamine, and the like. Examples of the sulfonium salt include CYRACURE UVI-6976, UVI-6992 (all manufactured by Dow Chemical), Sun-Aid SI-60L, SI-80L (manufactured by Sanshin Chemical), Adekaoptomer SP-150, SP-170 ( ADEKA), Uvacure 1590 (manufactured by Daicel UCB), and the like. Examples of the iodonium salt type include UV9380C (manufactured by Momentive Performance Materials Japan) and IRGACURE 250 (manufactured by Ciba Japan).

  Examples of photopolymerization initiators that generate anions include alkyl lithium, carbamate derivatives, oxime ester derivatives, and photoamine generators.

  The addition amount of a photoinitiator is 0.001 mass%-5 mass% with respect to photocurable resin, Preferably it is 0.01 mass%-3 mass%, More preferably, it is 0.05 mass%-1 mass. %.

C) Mold C-1) Master Mold Hereinafter, referring to FIGS. 2A and 2B, the compound lens 200 shown in FIG. 1A and the wafer lens 100 shown in FIG. An example of a mold for manufacturing will be described. For molding the wafer lens 100, a master mold 30 and a sub master mold 40 are used as molds.

  As shown in FIG. 2A, the master die 30 has a rectangular parallelepiped shape, and has a first transfer surface 31 for forming a second transfer surface 43 of a sub-master die 40 described later on the end face 30a. . The first transfer surface 31 corresponds to the positive mold of the first molding surface 102a of the first resin layer 102 of the wafer lens 100 finally obtained. The first transfer surface 31 includes a first optical transfer surface 31a for forming the first optical surface 11d of the first molding surface 102a and a first flange transfer surface 31b for forming the first flange surface 11g. Including. A plurality of first optical transfer surfaces 31a are arranged in an array and are formed in a substantially hemispherical convex shape.

  The master mold 30 is generally formed of a metal material. Examples of the metal material include iron-based materials, iron-based alloys, and non-ferrous alloys. Examples of iron-based materials include hot dies, cold dies, plastic dies, high-speed tool steel, general structural rolled steel, carbon steel for mechanical structures, chrome / molybdenum steel, and stainless steel. Among these, examples of the plastic mold include pre-hardened steel, quenched and tempered steel, and aging treated steel. Examples of the pre-hardened steel include SC, SCM, and SUS. An example of the SC system is PXZ. Examples of the SCM system include HPM2, HPM7, PX5, and IMPAX. Examples of the SUS system include HPM38, HPM77, S-STAR, G-STAR, STAVAX, RAMAX-S, and PSL. Examples of the iron-based alloy include alloys disclosed in JP-A-2005-113161 and JP-A-2005-206913. As a non-ferrous alloy, a copper alloy, an aluminum alloy, and a zinc alloy are mainly well known, and examples thereof include alloys disclosed in JP-A-10-219373 and JP-A-2000-176970. The master mold 30 may be made of metal glass or amorphous alloy. Examples of the metallic glass include PdCuSi and PdCuSiNi. Metallic glass has high machinability in diamond cutting and less tool wear. Examples of the amorphous alloy include electroless or electrolytic nickel phosphorous plating, and have good machinability in diamond cutting. These highly machinable materials may constitute the entire master mold 30 or may cover only the surface of the optical transfer surface, in particular, by a method such as plating or sputtering.

C-2) Submaster Mold As shown in FIG. 2B, the submaster mold 40, which is a resin mold, has a square plate shape, a submaster molding section 41 that is a resin section, and a light transmissive submaster substrate. 42. The sub master molding part 41 and the sub master substrate 42 have a laminated structure. The sub master molding unit 41 has a second transfer surface 43 that forms the first molding surface 102a of the wafer lens 100 on the end surface 41a. The second transfer surface 43 corresponds to the negative type of the first molding surface 102a of the wafer lens 100. The second transfer surface 43 includes a second optical transfer surface 43a for forming the first optical surface 11d of the first molding surface 102a and a second flange transfer surface 43b for forming the first flange surface 11g. Including. The second optical transfer surface 43a is transferred by the first optical transfer surface 31a, and a plurality of second optical transfer surfaces 43a are arranged in an array, and are formed in a substantially hemispherical concave shape.

  The sub master molding part 41 is formed of a resin material 41b. Examples of the resin material 41b include a photocurable resin, and an epoxy resin similar to the first resin layer 102 of the wafer lens 100 can be used. Acrylic resins, allyl ester resins, vinyl resins and the like can also be used. The resin material 41b is preferably transparent.

A release agent is applied on the second transfer surface 43 of the sub master molding unit 41. As a mold release agent, for example, OPTOOL DSX (manufactured by Daikin Industries, Ltd.) can be mentioned. An inorganic oxide film is provided between the sub master molding portion 41 and the release agent in order to improve the adhesion of the release agent. Examples of the inorganic oxide film include SiO ₂ . The inorganic oxide film is formed by, for example, vacuum deposition, sputtering or the like. The resin material 41b may be a resin having good releasability, that is, a resin that can be released without applying a release agent.

  The sub master substrate 42 is formed of a material having smoothness such as quartz, glass, silicon wafer, metal, and resin. In consideration of transparency or light transmission (the point that light can be irradiated from above or from below), the sub master substrate 42 is preferably made of quartz, glass, or the like.

  The master mold 30 and the sub master mold 40 used for molding the first resin layer 102 in the wafer lens 100 have been described above. However, the same mold is used when the second resin layer 103 is molded. In this case, for example, a master die 30 having a concave first transfer surface 31 is used, and a sub master die 40 having a convex second transfer surface 43 is used. Thereby, the second molding surface 103 a of the second resin layer 103 is formed by the sub master mold 40.

D) Manufacturing method of wafer lens and compound lens Wafer lens 100 performed using the master mold 30 and the sub master mold 40 described above with reference to FIGS. 3 (A) to 3 (F), FIG. 4 and FIG. The manufacturing process will be described. Hereinafter, the molding of the first resin layer 102 will be described, but the same process is performed for the molding of the second resin layer 103. 3A to 3F illustrate that steps S14 to S17, which will be described later, are sequentially performed on one surface of the substrate 101, each step is performed on both surfaces of the substrate 101. You may perform the next process after performing.

  First, the master mold 30 (see FIG. 3A) corresponding to the final shape of the first resin layer 102 is manufactured by grinding or the like (step S11). Next, a resin material 41b is applied on the master die 30, and ultraviolet rays are irradiated by a UV generator (not shown) while pressing the sub-master substrate 42 from above the master die 30, and the resin material 41b sandwiched therebetween is applied. Photocuring is performed (step S12). At this time, the first transfer surface 31 of the master mold 30 is transferred to the resin material 41b, and the second transfer surface 43 (second optical transfer surface and second flange transfer surface) is formed on the resin material 41b. Thereby, the sub master molding part 41 is formed. Examples of the light source used in the UV generator include a xenon arc lamp, a high-pressure mercury lamp, a metal halide lamp, a UV laser, a xenon flash lamp, and an LED. The transfer position on the sub-master substrate 42 is changed, and the sub-master type curing process (step S12) of this process and the sub-master mold release process (step S13) of the next process are repeated to further increase the second transfer surface 43. You may form in an array form.

  Next, as shown in FIG. 3B, the sub-master mold 40 is manufactured by releasing the sub-master molding portion 41 and the sub-master substrate 42 as a single unit from the master mold 30 (step S13). Thereafter, although not shown, an inorganic oxide film is formed on the second transfer surface 43 of the sub master mold 40. The inorganic oxide film is formed by, for example, vacuum deposition or sputtering. Further, a release agent is applied on the inorganic oxide film.

Next, the wafer lens 100 is produced. First, as shown in FIG. 3C, metal oxide films 104 are formed on both surfaces of the substrate 101 (step S14). The metal oxide film 104 is formed by, for example, vacuum vapor deposition or sputtering. For example, when the metal oxide film 104 is formed by vacuum deposition, a high-refractive material and a low-refractive material are alternately stacked on the one surface 101 a of the substrate 101 using the vacuum device 60. By the operation of the driving device 61 of the vacuum device 60, for example, Ta ₂ O ₅ is heated as a highly refractive material from the vapor deposition source 62, vaporized or sublimated, and deposited on one surface 101 a of the substrate 101. Further, by the operation of the driving device 61, for example, SiO ₂ is heated as a low refractive material from the vapor deposition source 63, vaporized or sublimated, and is deposited on one surface 101 a of the substrate 101. The metal oxide film 104 is formed to have a thickness of, for example, 40 nm to 60 nm, a film density of 1.5 g / cm ^{3 to} 2.0 g / cm ³ , and a compressive stress of 90 MPa to 150 MPa.

  Next, as shown in FIG. 3D, a stop 105 is formed on the surfaces of the metal oxide films 104 on both surfaces of the substrate 101 (step S15). The diaphragm 105 is formed, for example, by forming an opaque metal film on both surfaces of the metal oxide film 104 by vapor deposition or sputtering, and then performing patterning to form the opening 105b. The diaphragm 105 can also be formed by depositing a dark photoresist and then performing patterning to form the opening 105b.

  Next, as shown in FIG. 3E, a resin 102 b (a photocurable resin that forms the first resin layer 102) is applied onto the sub master mold 40, and the substrate 101 is pressed from above the sub master mold 40. While the ultraviolet ray is irradiated by a UV generator (not shown), the resin 102b sandwiched therebetween is photocured (step S16). At this time, the second transfer surface 43 of the sub-master mold 40 is transferred to the resin 102b, and the first molding surface 102a (the first optical surface 11d and the first flange surface 11g) is formed on the resin 102b. Thereby, the first resin layer 102 is formed. In addition, you may make it harden | cure by heat in order to make it harden | cure after photocuring.

  Although not shown, the second resin layer 103 may be formed on the other surface 101b of the substrate 101 in the same process as described above.

  Thereafter, as shown in FIG. 3F, the first resin layer 102 and the substrate 101 are integrally released from the sub-master mold 40 (step S17). When the first resin layer 102 is not formed, the second resin layer 103 is formed by performing the same process, and the wafer lens 100 is completed by releasing the sub master mold 40. Note that the wafer lens 100 may be released in a lump after the first and second resin layers 102 and 103 are formed.

  After that, as shown in FIG. 5, the wafer lens 100 is cut, that is, diced along the cut line DX (step S18). Here, the cut line DX is set at a portion where the substrate 101, the first and second resin layers 102 and 103, and the metal oxide film 104 overlap, and is not set on the diaphragm 105. The film thicknesses of the resin layers 102 and 103 in the cut line DX are preferably 100 μm or less, more preferably 80 μm or less in order to further improve the dicing resistance. The wafer lens 100 is cut into a quadrangular prism shape and becomes a compound lens 200. Since both the resin 102b of the first and second resin layers 102 and 103 and the metal oxide film 104 have flexibility, rapid stress release and brittle fracture (chipping) of the resin 102b do not occur during cutting. Therefore, the state where the resin 102b is peeled off from the substrate 101 starting from chipping does not occur.

  According to the optical element assembly or the like described above, between the substrate 101 and the resin 102b of the first and second resin layers 102 and 103 that have been given flexibility by reducing the crosslink density within a range where the reflow resistance does not deteriorate. The metal oxide film 104, which can relieve the internal stress of the resin and has low stress and low film density, is provided. As a result, when the portion where the substrate 101 and the first and second resin layers 102 and 103 overlap, that is, when the cut line DX is cut, the first and second portions are caused by chipping (chips) of the cut surface and stress at the time of cutting. It is possible to prevent the two resin layers 102 and 103 from peeling and the interface destruction of the substrate 101 to occur, and to improve the dicing resistance. As a result, the first and second resin layers 102 and 103 do not peel from the substrate 101 in the subsequent reflow process, and the reliability of the optical element can be improved. In other words, by ensuring the flexibility of the resin 102b and the flexibility of the metal oxide film 104 serving as the base of the resin 102b, the composite lens 200, which is an optical element, is exposed to a high temperature such as a reflow process. The first and second resin layers 102 and 103 do not peel off, and the reliability of the compound lens 200 can be improved.

[Example 1]
Hereinafter, the result of the evaluation test of the compound lens 200 manufactured by the manufacturing method of the present invention will be described.

  In this embodiment, an epoxy resin is used as the resin 102b for forming the first resin layer 102. Specifically, bisphenol A type epoxy resin was used. Moreover, aromatic sulfonium which is a cationic photopolymerization initiator, or diethylenetriamine was used as a photopolymerization initiator. The value of the loss tangent tan δ of the resin 102b was adjusted by changing the proportion of the viscosity-adjusting epoxy monomer added to the resin material. Specifically, allyl glycidyl ether (monofunctional), neopentyl glycol diglycidyl ether (bifunctional), and trimethylpropane polyglycidyl ether (trifunctional) were used as the epoxy monomer. Epoxy monomers were used in such a manner that the amount of trifunctional monomers was increased when the loss tangent tan δ was decreased, and the amount of monofunctional monomers was increased when the loss tangent tan δ was increased. As the substrate 101, a circular glass flat plate having a diameter of 4 inches and a thickness of 0.3 mm was used. And it shape | molded using the shaping | molding die so that 81 lenses with a lens diameter of 2 mm and the thickness on optical axis OA may be arranged in a matrix form of 81 pieces of 9x9. In the curing process of wafer lens 100 (corresponding to step S16 above), UV light irradiation was performed at room temperature using a mercury lamp at an intensity of 20 mW for 600 seconds, followed by heating at 150 ° C. for 1 hour. The film thickness of the cut line DX is adjusted by pressure control when the resin is spread. In the dicing step (corresponding to step S18), dicing saw DAD3350 (manufactured by Disco Corporation) was used for dicing. In the dicing, the spindle rotation speed is 13000 / min, the blade thickness is 0.1 mm, the cutting speed is 2.0 mm / min, the length of one side of the compound lens 200 after singulation is 2.2 mm, and the cutting line DX is The width was 0.2 mm.

  Table 1 shows the results of an evaluation test of the composite lens 200 and the composite lens of the comparative example. The evaluation test includes the presence or absence of resin peeling during dicing (dicing resistance), the presence or absence of resin peeling during heating (reliability after heating), and the presence or absence of resin peeling during a temperature cycle test (TC (Temperature Cycling) test). (Reliability after TC test). In the comparative example, the conditions of the metal oxide film and the resin layer on the substrate are changed. For the storage elastic modulus E ′ and loss elastic modulus E ″ of the resin layer, a measurement resin sample having a diameter of 8 mm and a thickness of 1 mm is prepared, and this is sandwiched between parallel plates, and a viscosity / viscoelasticity measuring device Rheostress RS6000 (Hacke) The measured value at each temperature is plotted on a graph by changing the temperature from −5 ° C. to 75 ° C. at a temperature rising temperature of 5 ° C./min. Calculated from The loss tangent tan δ was calculated from the equation of loss tangent tan δ = loss elastic modulus E ″ / storage elastic modulus E ′ using the calculated storage elastic modulus E ′ and loss elastic modulus E ″. The film density of the metal oxide film was measured using an X-ray diffractometer MXP21 (manufactured by Mac Science). The compressive stress of the metal oxide film was measured using a flatness measuring machine FT-900 (manufactured by NIDEK).

  The evaluation of the presence or absence of peeling of the resin in the dicing resistance was performed by observing with a microscope the presence or absence of peeling of the resin layer (first lens element) on the flat plate portion of the compound lens after dicing.

  The evaluation of the presence or absence of peeling of the resin during heating was carried out by microscopic observation of the presence or absence of peeling of the resin layer (first lens element) on the flat plate portion of the compound lens after being heated in an oven at 125 ° C. for 24 hours.

  Evaluation of the presence or absence of peeling of the resin in the TC test was performed by placing each cycle in an 85 ° C. state and an environment of −40 ° C. for 30 minutes as one cycle, and this was repeated for 50 cycles. The presence or absence of peeling of the lens element was observed with a microscope.

  In each of the above tests, the state of the singulated compound lens was evaluated. “◎” when the composite lens with peeling or interface breakage is less than 10% of the whole, “◯” when it is 10% or more and less than 30%, and “△” when it is 30% or more and less than 50%. In the case of 50% or more, “x” was assigned. When the test result of the dicing resistance is “x”, that is, when it becomes defective, the reliability test is not performed. It should be noted that the evaluations of “Δ”, “◯”, and “◎” are allowable ranges of dicing resistance or reliability.

The metal oxide films in Table 1 were formed using the vapor deposition method in any of (i) to (iv), but ion assist was used only for the vapor deposition method (iii). Specifically, in the vapor deposition methods (i), (ii), and (iv), the oxygen gas pressure during film formation is set to 1.2 × 10 ⁻² Pa, and Ta ₂ O ₅ , SiO in order from the substrate 101 side. ₂ , Ta ₂ O ₅ and SiO ₂ layers were formed. In the vapor deposition method (i), Ta ₂ O ₅ and SiO ₂ were vapor-deposited at a film forming temperature of 250 ° C. In this case, the thickness of the formed metal oxide film was 46 nm. This metal oxide film does not have an infrared reflection function. In the vapor deposition method (ii), Ta ₂ O ₅ and SiO ₂ were vapor-deposited at a film forming temperature of 300 ° C. In this case, the thickness of the formed metal oxide film was 48 nm. This metal oxide film does not have an infrared reflection function. In the vapor deposition method (iv), Ta ₂ O ₅ and SiO ₂ were vapor-deposited at a film forming temperature of 280 ° C. In this case, the thickness of the formed metal oxide film was 50 nm. This metal oxide film has an infrared reflection function. On the other hand, in the vapor deposition method (iii), the oxygen gas pressure at the time of film formation is set to 2.0 × 10 ⁻² Pa, and a layer of TiO ₂ , SiO ₂ , TiO ₂ , SiO ₂ is formed from the substrate 101 side. Oxygen 60 sccm and argon 20 sccm were introduced during the beam. In the vapor deposition method (iii), TiO ₂ and SiO ₂ were vapor-deposited at a film forming temperature of 120 ° C. In this case, the thickness of the formed metal oxide film was 56 nm. This metal oxide film does not have an infrared reflection function.

表１に示すように、サンプル３、４、６、９、１０、１２、１３、１６、１７、１９、２０は、樹脂の損失正接が０．３０以上０．５０以下であり、金属酸化物膜の膜密度が１．５ｇ／ｃｍ^３以上２．０ｇ／ｃｍ^３以下であり、カットラインＤＸ（樹脂の切断される部分）の膜厚が８０μｍ以下の条件を満たした。この場合、複合レンズは、各試験において許容範囲となる結果となった。このうちサンプル３、６、９、１２、１６、１９は、樹脂の２５℃における貯蔵弾性率が２ＧＰａ以上３ＧＰａ以下であり、金属酸化物膜の圧縮応力が９０ＭＰａ以上１５０ＭＰａ以下の条件も満たした。この場合、複合レンズは、各試験において比較的良好な結果となった。

As shown in Table 1, Samples 3, 4, 6, 9, 10, 12, 13, 16, 17, 19, and 20 have a loss tangent of the resin of 0.30 to 0.50, and the metal oxide The film density of the film was 1.5 g / cm ³ or more and 2.0 g / cm ³ or less, and the film thickness of the cut line DX (part where the resin was cut) satisfied the condition of 80 μm or less. In this case, the composite lens resulted in an acceptable range in each test. Samples 3, 6, 9, 12, 16, and 19 among them had a storage elastic modulus at 25 ° C. of 2 GPa or more and 3 GPa or less, and a metal oxide film had a compressive stress of 90 MPa or more and 150 MPa or less. In this case, the compound lens gave relatively good results in each test.

  On the other hand, when no metal oxide film was provided on the substrate as in Samples 2, 8, and 15, dicing resistance was poor. In Samples 1, 7, and 14, the loss tangent of the resin did not satisfy the condition of 0.30 or more and 0.50 or less, and the evaluation was poor in any of the tests. Samples 5, 11, and 18 did not satisfy the condition that the compressive stress of the metal oxide film was 90 MPa or more and 150 MPa or less, and the evaluation was poor in any of the tests.

  The optical element assembly according to the present embodiment has been described above, but the optical element assembly according to the present invention is not limited to the above. For example, in the above embodiment, the shapes and sizes of the first and second optical surfaces 11d and 12d can be changed as appropriate according to the application and function.

  In the above embodiment, the first and second resin layers 102 and 103 are formed on the entire surface of the substrate 101. However, without forming the first and second resin layers 102 and 103 on the entire surface of the substrate 101, for example, The first and second lens elements 11 and 12 and the first and second lens elements 11 and 12 adjacent thereto may be partially connected with resin.

  Moreover, in the said embodiment, the wafer lens 100 does not need to be disk shape, but can have various outlines, such as an ellipse. For example, the dicing process can be simplified by forming the wafer lens 100 into a square plate shape from the beginning.

  Moreover, in the said embodiment, the number of the 1st and 2nd lens elements 11 and 12 formed in the wafer lens 100 is not restricted to nine of illustration, It can also be made into two or more plurality. At this time, the arrangement of the first and second lens elements 11 and 12 is preferably on a lattice point for convenience of dicing. Further, the interval between the adjacent lens elements 11 and 12 is not limited to the illustrated one, and can be set as appropriate in consideration of workability and the like.

  Moreover, in the said embodiment, you may shape | mold the molded article which is not the wafer lens 100 but the number of the 1st and 2nd lens elements 11 and 12 is one. In this case, the compound lens 200 is not cut out from the wafer lens 100, but is cut along the outer shapes of the first and second flange portions 11b and 12b.

  Moreover, in the said embodiment, although resin was apply | coated to the 2nd transfer surface 43 of the submaster type | mold 40, you may apply | coat resin to the one surface 101a and the other surface 101b of the board | substrate 101. FIG.

  Moreover, in the said embodiment, you may apply | coat a coupling agent to the one surface 101a and the other surface 101b of the board | substrate 101 previously. Further, a release agent may be applied in advance to the first transfer surface 31 of the master mold 30.

  Moreover, in the said embodiment, you may provide a resin layer only in the one surface 101a of the board | substrate 101 of the wafer lens 100, or the other surface 101b.

  Further, in the above embodiment, the stop body 105a of the stop 105 is not provided in the planned cutting portion AR1, but it is provided if it does not affect the first and second resin layers 102, 103 and the like when the wafer lens 100 is cut. Also good.

  In the above embodiment, the metal oxide film 104 is an infrared reflection film, but may be an antireflection film.

DESCRIPTION OF SYMBOLS 11, 12 ... Lens element, 11a, 12a ... Lens main body, 11b, 12b ... Flange part, 11d, 12d ... Optical surface, 11g, 12g ... Flange surface, 13 ... Flat plate part, 30 ... Master type | mold, 31a, 43a ... Optical Transfer surface, 31b, 43b ... Flange transfer surface, 40 ... Submaster mold, 41 ... Submaster molding part, 41b ... Resin material, 42 ... Submaster substrate, 60 ... Vacuum device, 100 ... Wafer lens, 101 ... Substrate, 102 , 103 ... Resin layer, 102 b ... Resin, 104 ... Metal oxide film, 105 ... Aperture, 200 ... Compound lens, OA ... Optical axis

Claims (10)

A substrate,
A metal oxide film provided on at least one surface of the substrate;
A resin layer having a plurality of lens portions provided on the metal oxide film and connected to each other by a resin;
With
The loss tangent of the resin layer represented by a ratio E ″ / E ′ between the storage elastic modulus E ′ of the resin layer and the loss elastic modulus E ″ of the resin layer is 0.30 or more and 0.50 or less. Yes,
The optical element assembly, wherein the metal oxide film has a film density of 1.5 g / cm ³ or more and 2.0 g / cm ³ or less.   The optical element assembly according to claim 1, wherein the storage elastic modulus of the resin layer at 25 ° C is 2 GPa or more and 3 GPa or less.   The optical element assembly according to any one of claims 1 and 2, wherein the compressive stress of the metal oxide film is 90 MPa or more and 150 MPa or less.   4. The optical element assembly according to claim 1, wherein a thickness of a portion of the resin layer to be cut is 100 μm or less. 5.   5. The optical element assembly according to claim 1, wherein the metal oxide film is one of an infrared reflection film and an antireflection film.   The optical element assembly according to any one of claims 1 to 5, wherein the resin layer is formed on the entire surface of at least one surface of the substrate.   An optical element obtained by dicing the optical element assembly according to any one of claims 1 to 6 to separate a plurality of lens portions. A film forming step of forming a metal oxide film on at least one surface of the substrate;
After the film formation step, a resin molding step of forming a resin layer having a plurality of lens portions connected to each other by a resin on the metal oxide film,
With
The loss tangent of the resin layer is 0.30 or more and 0.50 or less,
The method for producing an optical element assembly, wherein the metal oxide film has a film density of 1.5 g / cm ³ or more and 2.0 g / cm ³ or less.   The method of manufacturing an optical element assembly according to claim 8, wherein the metal oxide film is formed by one of vacuum deposition and sputtering.   An optical element assembly obtained by the method for manufacturing an optical element assembly according to any one of claims 9 and 10, comprising a cutting step of cutting the substrate and the resin layer for each of a plurality of lens portions. A method for producing an optical element characterized by the above.

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