Method for manufacturing optical module, and optical module
By combining optically transparent resin light curing and sealing resin with a low linear expansion coefficient in the optical module, the problem of bump joint fracture caused by the optically transparent resin containing silica filler is solved, and the thermal stability and reliability of the optical module are improved.
Patent Information
- Application Number
- CN202480013604.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-07
- Filing Date
- 2024-01-22
- Publication Date
- 2025-10-03
AI Technical Summary
In optical modules, optically transparent resins containing fillers such as silica can cause light scattering or blocking, and have a high thermal expansion coefficient, which can easily cause the bump joints to break. This is especially true when electrodes are configured on one side of the optical element. During thermal expansion, the bump joints are susceptible to greater stress and breakage.
An optically transparent resin is photocured between the optical waveguide and the light-receiving/light-emitting portion, and a sealing resin with a low linear expansion coefficient is injected into the gap between the substrate and the optical element. The gap is sealed by thermal curing. Electrodes are arranged only on one side of the optical element. The combined sealing structure of the optically transparent resin and the sealing resin suppresses breakage at the bump joint.
The breakage of the bump joint is effectively suppressed, the thermal cycle stability and reliability of the optical module are improved, and the damage to the bump joint caused by thermal stress is reduced.
Smart Images
Figure CN120752565A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for manufacturing an optical module in which an optical element having a light receiving portion or a light emitting portion is flip-chip mounted on a substrate having an optical waveguide formed thereon, and the optical module. Background Art
[0002] Conventionally, flip-chip mounting, in which a semiconductor element is mounted on a circuit substrate via bumps, is a well-known method for mounting semiconductor elements on circuit substrates. In flip-chip mounting, an underfill material is filled between the circuit substrate and the semiconductor element to seal the bump joints and secure the circuit substrate and semiconductor element in other areas.
[0003] Patent Document 1 discloses an optical module in which an optical element, including a light receiving unit and a light emitting unit, is flip-chip mounted on a substrate having an optical waveguide formed thereon via bumps. Because the optical waveguide, the light receiving unit, and the light emitting unit form an optical path, the gap between the substrate and the optical element is filled with an optically transparent resin as an underfill material.
[0004] Prior art literature
[0005] Patent Literature
[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-4935 Summary of the Invention
[0007] Resins such as epoxy resin used as underfill materials have a large thermal expansion rate and may cause breakage of the bump bonding portion. Therefore, the underfill material generally contains a filler such as silica having a small linear expansion coefficient.
[0008] However, in an optical module, if a filler such as silica is contained in the optically transparent resin filling the gap between the substrate and the optical element, light is scattered or blocked by the filler. Therefore, it is not possible to contain a filler such as silica in the optically transparent resin.
[0009] Therefore, the linear expansion coefficient of an optically transparent resin that does not contain a filler such as silica increases, and when thermal stress is applied to the optically transparent resin during a heat cycle test, for example, there is a problem that the bump bonding portion may break.
[0010] In particular, when an electrode is disposed on only one side of an optical component, the bump bond portion is formed on that side. Therefore, when the optically transparent resin thermally expands, the side of the optical component not constrained by the bump bond portion will significantly deform, with the bump bond portion acting as a fulcrum. Consequently, there is a problem of applying high stress to the bump bond portion, making it more susceptible to fracture.
[0011] The present invention has been made in view of this point, and its main object is to provide a method for manufacturing an optical module and an optical module capable of suppressing breakage of bump bonding portions in an optical module in which an optical element is flip-chip mounted on a substrate having an optical waveguide formed thereon.
[0012] The present invention relates to a method for manufacturing an optical module in which an optical element having a light receiving portion and / or light emitting portion formed on its surface is flip-chip mounted on a substrate having an optical waveguide formed on its surface, wherein an electrode formed on the surface of the optical element is disposed only on one side of the optical element. The method comprises: arranging the substrate and the optical element so as to face each other and bonding the electrode formed on the surface of the substrate to the electrode formed on the surface of the optical element via a bump; injecting a light-curing optically transparent resin into a gap between the substrate and the optical element; irradiating light from the optical waveguide toward the light receiving portion and / or light emitting portion to photocure the optically transparent resin between the optical waveguide and the light receiving portion and / or light emitting portion; removing uncured portions of the optically transparent resin; injecting a heat-curing sealing resin having a smaller linear expansion coefficient than that of the optically transparent resin into the gap between the substrate and the optical element; and thermally curing the sealing resin.
[0013] The optical module according to the present invention comprises: a substrate having an optical waveguide formed on its surface; and an optical element having a light receiving portion and / or a light emitting portion formed on its surface, the optical element being flip-chip mounted on the substrate. Electrodes formed on the surface of the optical element are disposed only on one side of the optical element, and the substrate and optical element are disposed opposite each other. The electrodes formed on the substrate surface and the electrodes provided on the surface of the optical element are bonded via bumps. The gap between the substrate and the optical element, and the region between the optical waveguide and the light receiving portion and / or light emitting portion, are sealed with an optically transparent resin, while the remaining region is sealed with a sealing resin having a lower linear expansion coefficient than the optically transparent resin.
[0014] According to the present invention, a method for manufacturing an optical module and an optical module can be provided in which an optical element is flip-chip mounted on a substrate having an optical waveguide formed thereon, and in which breakage of a bump bond can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a cross-sectional view schematically showing the structure of the optical module in accordance with the first embodiment of the present invention.
[0016] Figure 2A This is a diagram illustrating the structure of a substrate.
[0017] Figure 2B This is a diagram illustrating the structure of a substrate.
[0018] Figure 2C This is a diagram illustrating the structure of a substrate.
[0019] Figure 3A This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0020] Figure 3B This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0021] Figure 3C This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0022] Figure 3D This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0023] Figure 4A This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0024] Figure 4B This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0025] Figure 4C This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0026] Figure 4D This is a cross-sectional view illustrating the method for manufacturing the optical module in the first embodiment.
[0027] Figure 5 This is a cross-sectional view schematically showing the structure of an optical module in accordance with Embodiment 2 of the present invention.
[0028] Figure 6A This is a cross-sectional view illustrating a method for manufacturing an optical module in the second embodiment.
[0029] Figure 6B This is a cross-sectional view illustrating a method for manufacturing an optical module in the second embodiment.
[0030] Figure 7 This is a cross-sectional view schematically showing the structure of an optical module in accordance with a third embodiment of the present invention.
[0031] Figure 8 This is a cross-sectional view schematically showing another structure of the optical module in accordance with the third embodiment of the present invention.
[0032] Figure 9A This is a cross-sectional view illustrating a method for manufacturing an optical module in the third embodiment.
[0033] Figure 9B This is a cross-sectional view illustrating a method for manufacturing an optical module in the third embodiment.
[0034] Figure 9C This is a cross-sectional view illustrating a method for manufacturing an optical module in the third embodiment. DETAILED DESCRIPTION
[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0036] (Implementation Method 1)
[0037] Figure 1 This is a cross-sectional view schematically showing the structure of the optical module in accordance with the first embodiment of the present invention.
[0038] like Figure 1 As shown, optical module 100 includes a substrate 101 having an optical waveguide 103 formed on its surface, and an optical element 105 having a light receiving portion (or light emitting portion) 105a formed on its surface. Optical element 105 is flip-chip mounted on substrate 101. Alternatively, optical element 105 may include either or both a light receiving portion and a light emitting portion.
[0039] The electrode 107 formed on the surface of the optical element 105 is arranged only on one side of the optical element 105. The substrate 101 and the optical element 105 are arranged to face each other, and the electrode 102 formed on the surface of the substrate 101 and the electrode 107 provided on the surface of the optical element 105 are bonded via the bump 104. Alternatively, the electrode 102 may be part of the wiring.
[0040] The gap between the substrate 101 and the optical element 105 and the area between the optical waveguide 103 and the light receiving part (or light emitting part) 105a are sealed with a light-cured optically transparent resin 108a, and the other areas are sealed with a heat-cured sealing resin 110a having a smaller linear expansion coefficient than the optically transparent resin 108a.
[0041] Light 106 incident on the core of optical waveguide 103 is reflected by reflector 101a provided on substrate 101, and is received by light receiving portion 105a via optically transparent resin 108a. Alternatively, if light emitting portion 105a is formed in optical element 105, light emitted from light emitting portion 105a is reflected by reflector 101a via optically transparent resin 108a, and is incident on the core of optical waveguide 103.
[0042] Reference Figures 2A to 2C The structure of the substrate 101 will be described in detail.
[0043] like Figure 2AAs shown, a first, generally trapezoidal groove 101b and a second, generally V-shaped groove 101c, connected to and deeper than first groove 101b, are formed on the surface of substrate 101. A reflector 101a for optical path conversion is formed at the tip of first groove 101b, directly below what will become a light receiving portion (or light emitting portion) 105a of optical element 105.
[0044] like Figure 2B As shown, an optical waveguide 103 is disposed within the first groove 101b and is optically coupled to a light receiving portion (or light emitting portion) 105a. The optical waveguide 103 extends from the reflector portion 101a toward the second groove 101c and is flush with the rear end 101d of the first groove 101b. An external waveguide (not shown) is disposed within the second groove 101c and is optically coupled to the optical waveguide 103.
[0045] like Figure 2C As shown, the optical waveguide 103 is composed of a core 103a having a relatively high refractive index for light propagation and a substantially square cross-section, and a cladding 103b having a lower refractive index than the core 103a. Both left and right surfaces of the core 103a are covered by the cladding 103b.
[0046] The core 103 a and the cladding 103 b are formed into a predetermined shape by applying a solution of a mixture of an organic material such as PMMA (Poly Methyl Methacrylate) resin or polycarbonate resin and an organic solvent onto the substrate 101 by spin coating, heat treating, or using photolithography.
[0047] The substrate 101 requires rigidity to protect against the effects of heat during flip-chip mounting of the optical element 105 and stresses caused by the operating environment. Furthermore, in optical modules, the optical element 105 must be mounted with high precision and positional fluctuations of the optical element 105 during use must be minimized. Therefore, a silicon substrate is preferably used for the substrate 101. Silicon substrates offer excellent flatness and allow for the etching of grooves on their surfaces with high precision, utilizing their crystal orientation. This allows the mirror portion 101a and the optical waveguide 103 to be precisely positioned within these grooves.
[0048] Next, refer to Figures 3A to 3D as well as Figures 4A to 4D A method for manufacturing the optical module 100 in the first embodiment will be described.
[0049] First, if Figure 3A As shown in FIG. 1 , a substrate 101 is prepared on the surface of which an optical waveguide 103 and an electrode 102 are formed. Alternatively, the electrode 102 may be a part of a wiring.
[0050] Next, if Figure 3BAs shown, bumps 104 are formed on electrodes 102. Bumps 104 are made of a bump material used for flip-chip connection, such as Au or AuSn. Alternatively, instead of forming bumps 104 on electrodes 102 on substrate 101, bumps 104 may be formed on the light-receiving portion (or light-emitting portion) 105a of optical element 105.
[0051] Next, if Figure 3C As shown, substrate 101 and optical element 105 are arranged facing each other, and electrodes 102 formed on the surface of substrate 101 and electrodes 107 provided on the surface of optical element 105 are bonded via bumps 104. Thus, optical element 105 is flip-chip mounted on substrate 101. Bump bonding can be performed by ultrasonic bonding, thermocompression bonding, or the like.
[0052] Next, if Figure 3D As shown, light 106 is irradiated from the outside onto optical waveguide 103 formed on substrate 101. Irradiated light 106 passes through optical waveguide 103, is bent 90 degrees by reflector 101a, and reaches light receiving portion (or light emitting portion) 105a of optical element 105. The wavelength of irradiated light 106 is preferably a wavelength for photocuring of optically transparent resin 108, described later, preferably ultraviolet light or infrared light.
[0053] Next, if Figure 4A As shown, while light is irradiated from optical waveguide 103 toward light receiving section (or light emitting section) 105a, optically transparent resin 108, which is cured by light, is injected from needle 201 into the gap between substrate 101 and optical element 105. At this time, only the portion of injected optically transparent resin 108 irradiated by light 106, i.e., the portion between optical waveguide 103 and light receiving section (or light emitting section) 105a, is photocured. As a result, optical coupling is established between optical waveguide 103 and light receiving section (or light emitting section) 105a via the photocured optically transparent resin 108a.
[0054] The optically transparent resin 108 does not necessarily need to be injected into the entire gap between the substrate 101 and the optical element 105 , but only needs to be injected into at least the region between the optical waveguide 103 and the light receiving portion (or light emitting portion) 105 a .
[0055] Examples of the optically transparent resin 108 that cures with light include elastomeric resins, polyimide resins, epoxy resins, silicone resins, polyurethane resins, polymer resins, acrylic resins, and polyolefin resins. Such optically transparent resins 108 do not contain fillers such as silica, and their linear expansion coefficient is typically below the glass transition temperature, ranging from 40 to 400 ppm / °C. Alternatively, the optically transparent resin 108 may be cured by light or heat.
[0056] Alternatively, instead of injecting the optically transparent resin 108 while irradiating light from the optical waveguide 103 toward the light receiving portion (or light emitting portion) 105 a, the optically transparent resin 108 may be injected into the gap between the substrate 101 and the optical element 105 and then irradiated with light from the optical waveguide 103 toward the light receiving portion (or light emitting portion) 105 a to photocure the optically transparent resin 108.
[0057] Next, if Figure 4B As shown, the uncured portion of the optically transparent resin 108 is removed by the chemical solution. By removing the uncured portion, only the optically transparent resin 108 a cured by light remains between the substrate 101 and the optical element 105 .
[0058] Next, if Figure 4C As shown, sealing resin 110 is injected from needle 202 into the gap between substrate 101 and optical element 105. Sealing resin 110 can be selected from a resin that has a lower linear expansion coefficient than optically transparent resin 108 and is cured by heat. For example, epoxy resin containing fillers such as silica is used as such sealing resin 110. Typically, the linear expansion coefficient of sealing resin 110 is 20 to 35 ppm, below the glass transition temperature.
[0059] Finally, if Figure 4D As shown, the sealing resin 110 is heated to thermally cure the sealing resin 110. Figure 1 The optical module 100 is constructed as shown.
[0060] In the first embodiment, only the area between the optical waveguide 103 and the light-receiving section (or light-emitting section) 105a is sealed with a photocured, optically transparent resin 108a. The remaining area is sealed with a sealing resin 110a having a lower linear expansion coefficient than the optically transparent resin 108a. Consequently, the optical element 105 is sealed with the sealing resin 110a having a lower linear expansion coefficient over nearly the entire area. As a result, even when thermal stress is applied to the sealing resin 110a during thermal cycling tests, etc., fracture of the joints of the bumps 104 (hereinafter referred to as "bump joints") is suppressed.
[0061] In addition, if Figure 1 As shown, the electrode 107 is disposed only on one side of the optical element 105. As a result, even if a bump bond is formed on one side of the optical element 105, the thermal expansion of the sealing resin 110a is small, so the optical element 105 does not deform significantly on the side not constrained by the bump bond, using the bump bond as a fulcrum. Therefore, a large stress is not applied to the bump bond, and breakage of the bump bond can be suppressed.
[0062] (Implementation Method 2)
[0063] Figure 5 This is a cross-sectional view schematically showing the structure of an optical module in accordance with Embodiment 2 of the present invention.
[0064] like Figure 5 As shown, optical module 100A includes a substrate 101 having an optical waveguide 103 formed on its surface, and an optical element 105 having a light receiving portion (or light emitting portion) 105a formed on its surface. Optical element 105 is flip-chip mounted on substrate 101. Alternatively, optical element 105 may include either or both a light receiving portion and a light emitting portion.
[0065] The electrode 107 formed on the surface of the optical element 105 is arranged only on one side of the optical element 105. The substrate 101 and the optical element 105 are arranged to face each other, and the electrode 102 formed on the surface of the substrate 101 and the electrode 107 provided on the surface of the optical element 105 are bonded via the bump 104. Alternatively, the electrode 102 may be part of the wiring.
[0066] The gap between the substrate 101 and the optical element 105 and the area between the optical waveguide 103 and the light receiving portion (or light emitting portion) 105a are sealed with a light-cured optically transparent resin 108a, the area including the bonding portion of the bump 104 (hereinafter referred to as the "bump bonding portion") is sealed with a heat-cured optically transparent resin 108b, and the area on the side of the optical element 105 opposite the bump bonding portion is sealed with a heat-cured sealing resin 110a having a smaller linear expansion coefficient than those of the optically transparent resins 108a and 108b.
[0067] Next, refer to Figure 6A as well as Figure 6B A method for manufacturing the optical module 100A in the second embodiment will be described.
[0068] First, with Figure 3A to Figure 3C In the same process as shown, the substrate 101 and the optical element 105 are arranged to face each other, and the electrode 102 formed on the surface of the substrate 101 and the electrode 107 provided on the surface of the optical element 105 are bonded via the bump 104 .
[0069] Next, if Figure 6AAs shown, while light is irradiated from optical waveguide 103 toward light receiving section (or light emitting section) 105a, optically transparent resin 108, which cures by light and heat, is injected from one side of optical element 105 where electrode 107 is arranged into the gap between substrate 101 and optical element 105 using needle 201. Furthermore, sealing resin 110, which has a lower linear expansion coefficient than optically transparent resin 108 and cures by heat, is injected from the opposite side of optical element 105 into the gap between substrate 101 and optical element 105 using needle 202. At this time, only the portion of injected optically transparent resin 108 irradiated by light 106, i.e., the portion between optical waveguide 103 and light receiving section (or light emitting section) 105a, is photocured.
[0070] Furthermore, optically and thermally curable optically transparent resin 108 may include, for example, elastomer resins, polyimide resins, epoxy resins, silicone resins, polyurethane resins, polymer resins, acrylic resins, and polyolefin resins. Such optically transparent resin 108 does not contain fillers such as silica, and its linear expansion coefficient is typically below the glass transition temperature, ranging from 40 to 400 ppm / °C.
[0071] Next, if Figure 6B As shown, the uncured portion of the optically transparent resin 108 and the sealing resin 110 are thermally cured. Figure 5 The optical module 100A is constructed as shown.
[0072] Furthermore, the steps of injecting the optically transparent resin 108 and the encapsulating resin 110 do not necessarily need to begin simultaneously. They can be performed at least at the timing that the optically transparent resin 108 located between the optical waveguide 103 and the light receiving section (or light emitting section) 105a is photocured, before the encapsulating resin 110 reaches the space between them. This allows optical coupling between the optical waveguide 103 and the light receiving section (or light emitting section) 105a via the photocured optically transparent resin 108a. This timing can be achieved by adjusting the injection pressure and injection speed of the optically transparent resin 108 and the encapsulating resin 110, as well as the start time of their respective injections.
[0073] In the second embodiment, the region between the optical waveguide 103 and the light receiving portion (or light emitting portion) 105a and the region including the bump joint are sealed with an optically transparent resin 108a that is photocured by the optically transparent resin 108 and an optically transparent resin 108b that is thermally cured by the optically transparent resin 108, and the region of the optical element 105 that faces the bump joint is sealed with a sealing resin 110a that has a smaller linear expansion coefficient than the optically transparent resins 108a and 108b. Figure 5 As shown, even though a bump bond is formed on one side of the optical element 105, the area on the side opposite the bump bond is sealed with the sealing resin 110a, which has a lower thermal expansion. Therefore, the optical element 105 does not significantly deform on the side not constrained by the bump bond, using the bump bond as a fulcrum. As a result, significant stress is not applied to the bump bond, and breakage of the bump bond can be suppressed.
[0074] Furthermore, in the first embodiment, a step of removing the uncured optically transparent resin 108 is required, but in the second embodiment, such a step is not required, and thus the manufacturing process of the optical module 100A can be simplified.
[0075] (Implementation Method 3)
[0076] Figure 7 This is a cross-sectional view schematically showing the structure of an optical module in accordance with a third embodiment of the present invention.
[0077] like Figure 7 As shown, optical module 100B includes a substrate 101 having an optical waveguide 103 formed on its surface, and an optical element 105 having a light receiving portion (or light emitting portion) 105a formed on its surface. Optical element 105 is flip-chip mounted on substrate 101. Alternatively, optical element 105 may include either or both a light receiving portion and a light emitting portion.
[0078] The electrode 107 formed on the surface of the optical element 105 is arranged only on one side of the optical element 105. The substrate 101 and the optical element 105 are arranged to face each other, and the electrode 102 formed on the surface of the substrate 101 and the electrode 107 provided on the surface of the optical element 105 are bonded via the bump 104. Alternatively, the electrode 102 may be part of the wiring.
[0079] The gap between substrate 101 and optical element 105, and the area between optical waveguide 103 and light-receiving section (or light-emitting section) 105a, is sealed with a light-cured, optically transparent resin 108a. The remaining area is sealed with a heat-cured, optically transparent resin 108b. Furthermore, the periphery of optical element 105, and the side facing the junction with bump 104 (hereinafter referred to as the "bump junction"), is sealed with a sealing resin 110a having a lower linear expansion coefficient than optically transparent resins 108a and 108b.
[0080] In addition, if Figure 7 As shown in FIG. 1 , one side of the bump joint side may also be sealed with a sealing resin 110a. Alternatively, as shown in FIG. Figure 8 As shown, the optical element 105 may be sealed with the sealing resin 110 a so as to cover not only the periphery of the optical element 105 but also the entire optical element 105 .
[0081] Next, refer to Figures 9A to 9C A method for manufacturing the optical module 100B in the third embodiment will be described.
[0082] First, with Figure 3A to Figure 3C In the same process as shown, the substrate 101 and the optical element 105 are arranged to face each other, and the electrode 102 formed on the surface of the substrate 101 and the electrode 107 provided on the surface of the optical element 105 are bonded via the bump 104 .
[0083] Next, if Figure 9A As shown, while light is irradiated from the optical waveguide 103 toward the light receiving section (or light emitting section) 105a, an optically transparent resin 108, which cures by light and heat, is injected from a needle 201 into the gap between the substrate 101 and the optical element 105. This causes the optically transparent resin 108 located between the optical waveguide 103 and the light receiving section (or light emitting section) 105a to be photocured. This optical coupling between the optical waveguide 103 and the light receiving section (or light emitting section) 105a is achieved via the photocured optically transparent resin 108a.
[0084] Alternatively, after injecting an optically transparent resin 108 that cures by light and heat into the gap between the substrate 101 and the optical element 105, light may be irradiated from the optical waveguide 103 toward the light receiving portion (or light emitting portion) 105a to photocure the optically transparent resin 108 between the optical waveguide 103 and the light receiving portion (or light emitting portion) 105a.
[0085] Next, if Figure 9B As shown, a sealing resin 110 having a smaller linear expansion coefficient than the optically transparent resins 108a and 108b and curing by heat is applied from the needle 202 to the periphery of the optical element 105 and to the side of the optical element 105 opposite to the side where the electrode 107 is arranged. In addition, the sealing resin 110 may also be applied to the side of the optical element 105 where the electrode 107 is arranged. Figure 8 In the optical module 100C shown, the sealing resin 110 may be applied to cover not only the periphery of the optical element 105 but also the entire optical element 105 .
[0086] Next, if Figure 9C As shown, the uncured portion of the optically transparent resin 108 and the sealing resin 110 are thermally cured. Figure 7 The optical module 100B is constructed as shown.
[0087] In embodiment 3, as Figure 7 as well as Figure 8As shown, the gap between substrate 101 and optical element 105 is sealed with optically transparent resin 108a, which is first photocured, and optically transparent resin 108b, which is then thermally cured. Furthermore, at least the side of optical element 105 facing the bump joint is sealed with sealing resin 110a, which has a lower coefficient of linear expansion than both optically transparent resins 108a and 108b. Therefore, even if a bump joint is formed on one side of optical element 105, the area facing the bump joint is sealed with sealing resin 110a, which has a lower coefficient of thermal expansion. Therefore, optical element 105 does not significantly deform on the side not constrained by the bump joint, using the bump joint as a fulcrum. As a result, significant stress is not applied to the bump joint, which can prevent the bump joint from breaking.
[0088] Furthermore, while the first embodiment requires a step of removing the uncured optically transparent resin 108 , the third embodiment does not require such a step, and thus the manufacturing process of the optical modules 100B and 100C can be simplified.
[0089] The present invention has been described above using preferred embodiments. However, such descriptions are not limiting and can, of course, be modified in various ways. For example, in the first to third embodiments described above, light is irradiated from the optical waveguide 103 toward the light receiving portion (or light emitting portion) 105a to photocure the optically transparent resin 108. However, if the light emitting portion 105a is formed on the surface of the optical element 105, light can also be irradiated from the light emitting portion 105a toward the optical waveguide 103 to photocure the optically transparent resin 108 located between the optical waveguide 103 and the light emitting portion 105a.
[0090] -Explanation of symbols-
[0091] 100, 100A, 100B, 100C optical modules
[0092] 101 substrate
[0093] 101a Reflector
[0094] 101b Slot 1
[0095] 101c Slot 2
[0096] 101d rear end
[0097] 102 Electrode (part of wiring)
[0098] 103 Optical Waveguide
[0099] 103a Core
[0100] 103b cladding
[0101] 104 Bump
[0102] 105 Optical Components
[0103] 105a Light receiving unit (or light emitting unit)
[0104] 106 Light
[0105] 107 electrodes
[0106] 108 optically clear resin
[0107] 108a Light-cured optically clear resin
[0108] 108b Optically clear resin that has been heat cured
[0109] 110 Sealing resin
[0110] 110a Heat-cured sealing resin
[0111] 201, 202 needles.
Claims
1. A method for manufacturing an optical module, wherein an optical element having a light receiving portion and / or a light emitting portion formed on the surface thereof is flip-chip mounted on a substrate having an optical waveguide formed on the surface thereof; The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The manufacturing method of the optical module includes: a step of arranging the substrate and the optical element so as to face each other, and bonding an electrode formed on a surface of the substrate to an electrode provided on a surface of the optical element via a bump; a step of injecting an optically transparent resin that is cured by light into a gap between the substrate and the optical element; a step of irradiating light from the optical waveguide toward the light receiving portion and / or light emitting portion to photocuring the optically transparent resin located between the optical waveguide and the light receiving portion and / or light emitting portion; a step of removing an uncured portion of the optically transparent resin; a step of injecting a sealing resin having a smaller linear expansion coefficient than the optically transparent resin and curing by heat into a gap between the substrate and the optical element; and a step of thermally curing the sealing resin.
2. The method for manufacturing an optical module according to claim 1, wherein: In the step of injecting the optically transparent resin, a step of photocuring the optically transparent resin is performed while irradiating light from the optical waveguide toward the light receiving section and / or light emitting section.
3. A method for manufacturing an optical module, wherein an optical element having a light receiving portion and / or a light emitting portion formed on the surface thereof is flip-chip mounted on a substrate having an optical waveguide formed on the surface thereof; The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The manufacturing method of the optical module includes: a step of arranging the substrate and the optical element so as to face each other, and bonding an electrode formed on a surface of the substrate to an electrode provided on a surface of the optical element via a bump; a step of injecting an optically transparent resin that cures by light and heat into a gap between the substrate and the optical element from one side of the optical element on which the electrode is disposed, while irradiating light from the optical waveguide toward the light receiving portion and / or light emitting portion; a step of injecting a sealing resin having a smaller linear expansion coefficient than the optically transparent resin and curing by heat from a side of the optical element that is opposite to the other side; and a step of thermally curing the uncured portion of the optically transparent resin and the sealing resin, The steps of injecting the optically transparent resin and injecting the sealing resin are performed at least at a time when the optically transparent resin located between the optical waveguide and the light receiving portion and / or light emitting portion is photocured before the sealing resin reaches between the optical waveguide and the light receiving portion and / or light emitting portion.
4. The method for manufacturing an optical module according to claim 3, wherein: The process of injecting the optically transparent resin and the process of injecting the sealing resin are started simultaneously.
5. A method for manufacturing an optical module, wherein an optical element having a light receiving portion and / or a light emitting portion formed on the surface thereof is flip-chip mounted on a substrate having an optical waveguide formed on the surface thereof; The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The manufacturing method of the optical module includes: a step of arranging the substrate and the optical element so as to face each other, and bonding an electrode formed on a surface of the substrate to an electrode provided on a surface of the optical element via a bump; a step of injecting an optically transparent resin that is cured by light and heat into a gap between the substrate and the optical element; a step of irradiating light from the optical waveguide toward the light receiving portion and / or light emitting portion to photocuring the optically transparent resin located between the optical waveguide and the light receiving portion and / or light emitting portion; a step of applying a sealing resin having a smaller linear expansion coefficient than the optically transparent resin and curing by heat to the periphery of the optical element and to a side of the optical element opposite to a side where the electrode is arranged; and a step of thermally curing the uncured portion of the optically transparent resin and the sealing resin.
6. The method for manufacturing an optical module according to claim 5, wherein: In the step of applying the sealing resin, the sealing resin is applied so as to cover the entire optical element including the periphery of the optical element.
7. The method for manufacturing an optical module according to claim 5, wherein: In the step of injecting the optically transparent resin, a step of photocuring the optically transparent resin is performed while irradiating light from the optical waveguide toward the light receiving section and / or light emitting section.
8. The method for manufacturing an optical module according to any one of claims 1, 3, and 5, wherein: A light emitting portion is formed on the surface of the optical element. Instead of irradiating light from the optical waveguide toward the light receiving portion and / or the light emitting portion, light is irradiated from the light emitting portion toward the optical waveguide to photo-cure the optically transparent resin between the optical waveguide and the light emitting portion.
9. An optical module comprising: a substrate having an optical waveguide formed on a surface thereof; and The optical element has a light receiving portion and / or a light emitting portion formed on the surface and is flip-chip mounted on the substrate. The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The substrate and the optical element are arranged to face each other, and electrodes formed on the surface of the substrate and electrodes provided on the surface of the optical element are bonded via bumps. The gap between the substrate and the optical element and the region between the optical waveguide and the light receiving portion and / or light emitting portion are sealed with an optically transparent resin, and the other regions are sealed with a sealing resin having a smaller linear expansion coefficient than the optically transparent resin.
10. An optical module comprising: a substrate having an optical waveguide formed on a surface thereof; and The optical element has a light receiving portion and / or a light emitting portion formed on the surface and is flip-chip mounted on the substrate. The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The substrate and the optical element are arranged to face each other, and electrodes formed on the surface of the substrate and electrodes provided on the surface of the optical element are bonded via bumps. The gap between the substrate and the optical element, the area between the optical waveguide and the light receiving portion and / or light emitting portion, and the area including the joint portion of the bump are sealed with an optically transparent resin, and the area on the side of the optical element opposite to the joint portion of the bump is sealed with a sealing resin having a smaller linear expansion coefficient than that of the optically transparent resin.
11. An optical module comprising: a substrate having an optical waveguide formed on a surface thereof; and The optical element has a light receiving portion and / or a light emitting portion formed on the surface and is flip-chip mounted on the substrate. The electrode formed on the surface of the optical element is arranged only on one side of the optical element. The substrate and the optical element are arranged to face each other, and electrodes formed on the surface of the substrate and electrodes provided on the surface of the optical element are bonded via bumps. The gap between the substrate and the optical element and the area between the optical waveguide and the light receiving portion and / or light emitting portion are sealed with a light-cured optically transparent resin, and the other areas are sealed with a heat-cured optically transparent resin. In addition, the periphery of the optical element and the side opposite to the joint of the bump are sealed with a sealing resin having a smaller linear expansion coefficient than that of the optically transparent resin.
12. The optical module according to claim 11, wherein: The entire optical element, including the periphery of the optical element, is sealed by the sealing resin.
Citation Information
Patent Citations
Optical module
JP2013004935A