Method for mounting optical connection component, and intermediate component of optical connection component

Abstract

A method for mounting an optical connection component according to the present disclosure is a method for mounting an optical connection component (70) that connects an optical waveguide component (50) to a circuit board (30). This mounting method comprises: a step for preparing an optical connection component (70) provided with a bottom surface that can be placed on a substrate main surface of a circuit board, a surface different from the bottom surface, and a recess formed In the surface; a step for embedding an embedded member (P) in at least a portion of the recess (73) in a state in which the bottom surface of the optical connection component (70) is placed on the main surface (30a) of the circuit board (30), thereby obtaining an optical connection component in which the embedded member is embedded in at least a portion of the recess as an intermediate component (700); a step for removing the embedded member from the recess; and a step for positioning the optical waveguide component (50) with respect to the optical connection component (70) by inserting a protrusion (63) protruding from the optical waveguide component (50) into the recess (73) from which the embedded member has been removed.

Description

Mounting method for optical connection parts and intermediate part for optical connection parts

[0001] This disclosure relates to a mounting method for an optical connecting component and an intermediate component for an optical connecting component. This application claims priority to Japanese Application No. 2024-063937, filed April 11, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] As an example of a conventional optical connecting component, for example, Patent Document 1 discloses a receptacle that connects an optical connector to an optical IC board. This receptacle is placed on the optical IC board and is connected to the optical connector by a pair of guide pins. The receptacle is formed with a pair of guide holes into which the pair of guide pins are respectively inserted.

[0003] US Patent Application Publication No. 2016 / 0370544

[0004] The mounting method for an optical connecting component disclosed herein is a method for mounting an optical connecting component to a circuit board, and includes the steps of: preparing an optical connecting component having a bottom surface mountable on a main surface of a circuit board, a surface different from the bottom surface, and a recess formed in the surface; obtaining an optical connecting component as an intermediate component with the recess at least partially embedded with an embedding member while the bottom surface of the optical connecting component is mounted on the main surface of the circuit board; removing the embedding member from the recess; and positioning the optical waveguide component relative to the optical connecting component by inserting a protrusion protruding from the optical waveguide component into the recess from which the embedding member has been removed.

[0005] FIG. 1A is a plan view showing an example of an optical communication module to which the optical connection assembly of the present disclosure can be applied. FIG. 1B is a cross-sectional view showing the optical communication module of FIG. 1A. FIG. 2A is a side view showing the optical connection assembly of FIG. 1A. FIG. 2B is a plan view showing an optical connecting component included in the optical connection assembly of FIG. 2A. FIG. 3A is a cross-sectional view showing a step of a mounting method for optical connecting components. FIG. 3B is a cross-sectional view showing a step subsequent to FIG. 3A. FIG. 3C is a cross-sectional view showing a step subsequent to FIG. 3B. FIG. 4 is a side view showing an optical connection assembly of Modification 1. FIG. 5A is a cross-sectional view showing a step of a mounting method for optical connecting components included in the optical connection assembly of FIG. 4. FIG. 5B is a cross-sectional view showing a step subsequent to FIG. 5A. FIG. 5C is a cross-sectional view showing a step subsequent to FIG. 5B. FIG. 6A is a cross-sectional view showing a step subsequent to FIG. 5C. FIG. 6B is a cross-sectional view showing a step subsequent to FIG. 6A. FIG. 7A is a side view showing an optical connection assembly of Modification 2. FIG. 7B is a plan view showing an optical connecting component included in the optical connection assembly of FIG. 7A. Fig. 8A is a side view showing an optical connection assembly of Modification 3. Fig. 8B is a plan view showing optical connecting parts included in the optical connection assembly of Fig. 8A. Fig. 9 is a side view showing the optical connection assembly of Modification 3.

[0006] [Problem to be Solved by the Present Disclosure] When mounting a receptacle as described above, it is expected that semiconductor mounting processes such as a cleaning process and a resin molding process will be performed. During these processes, fluids such as cleaning liquid, residue, and molding resin may flow into the guide holes formed in the receptacle. If an optical connector is connected to the receptacle using a guide pin while such fluids remain in the guide holes, the fluids that have flowed into the guide holes may obstruct the positioning accuracy of the optical connector relative to the receptacle, resulting in increased optical loss.

[0007] The present disclosure provides a mounting method for an optical connecting part and an intermediate part for the optical connecting part that can reduce optical loss.

[0008] [Advantages of the Present Disclosure] According to the mounting method of an optical connecting part and the intermediate part of an optical connecting part of the present disclosure, it is possible to reduce optical loss. [Description of the Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0009] (1) A mounting method for an optical connecting component disclosed herein is a method for mounting an optical connecting component that connects an optical waveguide component to a circuit board, and includes the steps of: preparing an optical connecting component having a bottom surface mountable on a main surface of a circuit board, a surface different from the bottom surface, and a recess formed in the surface; obtaining an optical connecting component as an intermediate component with the recess at least partially embedded with an embedding member while the bottom surface of the optical connecting component is placed on the main surface of the circuit board; removing the embedding member from the recess; and positioning the optical waveguide component relative to the optical connecting component by inserting a protrusion protruding from the optical waveguide component into the recess from which the embedding member has been removed.

[0010] According to the above-described mounting method, even when processes such as a cleaning process and a resin molding process are performed during the semiconductor mounting process, the embedding member embedded in at least a portion of the recess can prevent fluids such as cleaning liquid, residue, and molding resin from flowing into the recess. Furthermore, by removing the embedding member from the recess, the recess can be made free of fluids. According to this method of temporarily embedding the embedding member in at least a portion of the recess, when connecting an optical waveguide component to an optical connecting component, the protruding portion from the optical waveguide component can be inserted into the recess without being obstructed by fluids remaining in the recess, thereby enabling accurate positioning of the optical waveguide component relative to the optical connecting component. As a result, optical loss between the optical waveguide component and the circuit board can be reduced.

[0011] (2) In the mounting method described in (1) above, the step of removing the embedding material from the recess may involve bringing the embedding material into contact with a solvent to dissolve the embedding material. This method makes it possible to easily remove the embedding material from the recess while avoiding process complexity, compared to a method of removing the embedding material from the recess without dissolving it.

[0012] (3) The mounting method described in (1) or (2) above may include at least one of the following steps: after obtaining the intermediate component, cleaning the intermediate component with a cleaning solution and before removing the filling material from the recess; and covering the intermediate component with a molded resin layer. During these steps, fluids tend to flow into the recess. In contrast, with the mounting method described above, even after these steps, the filling material can prevent fluids from flowing into the recess, thereby effectively achieving the effect described in (1).

[0013] (4) The mounting method described in (3) above may further include the steps of: after obtaining the intermediate component, covering the intermediate component with a molded resin layer and polishing the molded resin layer so that the embedded member is exposed from the molded resin layer before removing the embedded member from the recess. Even when the intermediate component is covered with the molded resin layer in this way, the embedded member can be exposed by polishing the molded resin layer, and the exposed embedded member can be easily removed from the recess.

[0014] (5) The optical connecting component of the present disclosure is an intermediate component obtained during an optical connecting component mounting process for connecting an optical waveguide component to a circuit board. This intermediate component includes a bottom surface that can be placed on the main surface of the circuit board, a surface different from the bottom surface, a recess formed on the surface, and an embedding member embedded in at least a portion of the recess and removable from the recess. With this intermediate component, even when processes such as a cleaning process and a resin molding process are performed during the semiconductor mounting process, the embedding member embedded in at least a portion of the recess can prevent fluids such as cleaning liquid, residue, and molding resin from flowing into the recess. Removing the embedding member from the recess can eliminate fluids from remaining in the recess. This configuration, in which the embedding member is temporarily embedded in at least a portion of the recess, allows the protrusion protruding from the optical waveguide component to be inserted into the recess without being obstructed by fluids remaining in the recess when connecting the optical waveguide component to the optical connecting component, thereby enabling accurate positioning of the optical waveguide component relative to the optical connecting component. As a result, the optical loss between the optical waveguide component and the circuit board can be reduced.

[0015] (6) In the intermediate component described in (5) above, the recess may accommodate the entire embedding member. The volume of the embedding member may be 50% or more and 100% or less of the volume of the internal space of the recess. In this case, the embedding member can more reliably prevent fluids from flowing into the recess, so that when connecting an optical waveguide component to an optical connecting component, insertion of the protrusion into the recess can be more reliably prevented from being hindered by fluids remaining in the recess.

[0016] (7) In the intermediate component according to (5) or (6), the surface may be aligned with the bottom surface along a direction intersecting the bottom surface. The recess may be a pair of through holes penetrating from the surface to the bottom surface. In this case, the length of the protrusion inserted into the recess can be made as long as possible, so that when the protrusion is inserted into the recess, the orientation of the optical waveguide component relative to the optical connecting component can be stabilized, and the optical waveguide component can be positioned with greater precision relative to the optical connecting component.

[0017] (8) In the intermediate component according to (5) or (6), the surface may be aligned with the bottom surface along a direction intersecting the bottom surface. The recess may be a pair of blind holes extending from the surface to a position not reaching the bottom surface. In this case, the adhesive for fixing the bottom surface of the optical connecting component to the main surface of the circuit board can be prevented from flowing from the bottom surface of the optical connecting component into the recess, thereby more reliably preventing fluids from flowing into the recess.

[0018] (9) In the intermediate part according to any one of (5) to (8), the embedding member may be formed of a dissolvable material that dissolves in a solvent upon contact with the solvent. In this case, compared to removing the embedding member from the recess without dissolving it, it becomes possible to easily remove the embedding member from the recess while avoiding a complicated process.

[0019] (10) In the intermediate component described in (9) above, the dissolving material may be a water-soluble resin that dissolves in a water-soluble solvent upon contact with the solvent. In this case, the water-soluble solvent used in the semiconductor mounting process can be used to more easily remove the filling material from the recess while avoiding process complications.

[0020] (11) In the intermediate component described in (9) above, the dissolvable material may be a positive resist that dissolves in an alkaline solution upon exposure to light. In this case, the filling material can be more easily removed from the recess by using exposure equipment and an alkaline solution used in the semiconductor mounting process.

[0021] (12) The intermediate component according to any one of (5) to (11) above may be formed of a material that transmits at least a portion of the wavelength range from ultraviolet light to visible light. In this case, the optical connecting component can be easily fixed to the circuit board using an ultraviolet-curing adhesive. Furthermore, when the embedding member is to be dissolved in an alkaline solution by exposure, the embedding member can be easily exposed to light.

[0022] (13) The intermediate component according to any one of (5) to (12) above may further include at least one optical waveguide exposed on the surface at a position different from the recess and extending from the surface to the bottom. The intermediate component may be surrounded by a molded resin layer. The surface may be exposed from the molded resin layer. In this configuration, even if the intermediate component is covered with the molded resin layer, the recess and the optical waveguide can be exposed from the molded resin layer by polishing the molded resin layer to expose the surface of the optical connecting component. In this case, the effort required to expose the recess and the optical waveguide from the molded resin layer can be reduced compared to when the recess and the optical waveguide are formed on different surfaces. When the recess and the optical waveguide are formed on the same surface, the relative positions of the recess and the optical waveguide can be maintained with precision, and the recess can be used to position the optical waveguide component relative to the optical connecting component, while accurately optically connecting the optical waveguide to the optical waveguide component. This reduces optical loss between the optical waveguide component and the optical waveguide.

[0023] (14) In the intermediate component described in (13) above, the surface may be aligned with the bottom surface along a direction intersecting the bottom surface. The optical waveguide and the recess may extend linearly from the surface toward the bottom surface. The angle between the direction in which the central axis of the recess extends and the direction in which the central axis of the optical waveguide extends may be 1 degree or less. In this case, the relative position of the recess exposed from the molded resin layer and the optical waveguide can be maintained with greater precision. Therefore, the recess can be used to position the optical waveguide component relative to the optical connecting component, and the optical connection of the optical waveguide to the optical waveguide component can be performed with greater precision. This allows for more effective reduction of optical loss between the optical waveguide component and the optical waveguide.

[0024] [Details of the embodiments of the present disclosure] Specific examples of the mounting method of an optical connecting component and the intermediate component of an optical connecting component of the present disclosure will be described in detail below with reference to the accompanying drawings. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0025] 1A and 1B performs optical communication via a plurality of optical fibers 500. The optical communication module 10 includes, for example, a communication LSI 20 and a plurality of optical connection assemblies 100.

[0026] In the optical communications module 10, for example, a communication LSI 20 and a plurality of optical connection assemblies 100 are mounted on a substrate 15. Each optical connection assembly 100 is connected to the communication LSI 20 by an electrical wiring 25. The substrate 15 is, for example, an interposer substrate. The electrical wiring 25 passes through, for example, the inside of the substrate 15 to connect the optical connection assemblies 100 and the communication LSI 20. The electrical wiring 25 may also pass through the surface layer of the substrate 15 to connect the optical connection assemblies 100 and the communication LSI 20.

[0027] The optical communications module 10 is required to be compact in order to efficiently utilize the storage space. As the optical communications module 10 becomes smaller, the optical connection assembly 100 comes closer to the communication LSI 20, which becomes hot. As a result, the optical connection assembly 100 is exposed to a high-temperature environment (e.g., 85°C or higher) due to the heat generated by the communication LSI 20. The optical communications module 10 of this embodiment is designed for use in such a high-temperature environment.

[0028] As shown in FIG. 2A, the optical connection assembly 100 includes, for example, an optical IC substrate 30, an optical connector 50, and an adapter 70.

[0029] In the optical connection assembly 100, the adapter 70 is mounted on the main surface 30a of the optical IC substrate 30, and the optical connector 50 is disposed in a position facing the adapter 70 in a vertical direction. Then, using the guide pins 63, the optical connector 50 is positioned relative to the adapter 70 in a state facing the adapter 70 in a vertical direction. In this state, the optical connector 50 is connected to the adapter 70 along the vertical direction. The adapter 70 and the optical connector 50 may be positioned relative to each other in a state facing the adapter 70 in a horizontal direction, or may be connected along the horizontal direction.

[0030] The optical IC substrate 30 is a substrate on which multiple optical ICs 31 are mounted on a main surface 30a, and is an example of a "circuit substrate" in the present disclosure. The optical IC substrate 30 is made of a material such as silicon, ceramic, or resin. The multiple optical ICs 31 are, for example, lined up in a row along one direction along the main surface 30a and exposed from the main surface 30a. Each optical IC 31 faces each optical fiber 500 of the optical connector 50, with the adapter 70 sandwiched between them.

[0031] The optical connector 50 is a component connected to the adapter 70 mounted on the optical IC substrate 30, and is an example of an "optical waveguide component" of the present disclosure. The optical connector 50 includes, for example, a ferrule 60 that holds the tip end of the optical fiber 500. The ferrule 60 includes, for example, a bottom surface 60a and a side surface 60b.

[0032] The lower surface 60a is a connection surface that is connected to the adapter 70 and faces the main surface 30a of the optical IC 31 across the adapter 70. A pair of guide pins 63 protrude from the lower surface 60a. Each guide pin 63 is fixed to the ferrule 60 and extends from the lower surface 60a toward the main surface 30a of the optical IC substrate 30. The pair of guide pins 63 protruding from the lower surface 60a are an example of a "protrusion" in the present disclosure. Each guide pin 63 is used to position the optical connector 50 and the adapter 70 relative to one another. The side surface 60b is an inclined surface that is inclined with respect to the lower surface 60a and the main surface 30a.

[0033] The optical connector 50 may be a glass substrate in which a plurality of optical fibers 500 are embedded. The optical connector 50 may be a glass substrate in which a plurality of refractive index change regions (optical waveguides) are formed by laser drawing. As the glass substrate in which the plurality of optical fibers 500 are embedded, for example, a porous glass substrate having a plurality of through holes into which the plurality of optical fibers 500 are respectively inserted may be used.

[0034] The adapter 70 is a component for connecting the optical connector 50 to the optical IC board 30 and is an example of an "optical connecting component" of the present disclosure. The adapter 70 is disposed between the lower surface 60a of the optical connector 50 and the main surface 30a of the optical IC board 30. The adapter 70 is, for example, a glass substrate formed from a glass material. This glass adapter 70 transmits at least some wavelengths within the wavelength range from ultraviolet light to visible light. "Transmitting at least some wavelengths within the wavelength range from ultraviolet light to visible light" means, for example, that a material with a thickness of 0.5 mm has a light transmittance of 50% or more when irradiated with light having a wavelength of 400 nm or more and 2000 nm or less, which is within the wavelength range from ultraviolet light to visible light. This glass adapter 70 is optically transparent to communication light from the optical fiber 500.

[0035] The adapter 70 is, for example, 1×10 －６The adapter 70 may have a linear thermal expansion coefficient of 5×10 or less. This linear thermal expansion coefficient is close to the linear thermal expansion coefficient of the silicon contained in the optical IC substrate 30, so even in a high-temperature environment, it is possible to reduce misalignment of the adapter 70 due to thermal stress caused by the difference between the linear thermal expansion coefficient of the adapter 70 and the linear thermal expansion coefficient of the optical IC substrate 30. Examples of materials for the adapter 70 include glass materials such as synthetic quartz glass, borosilicate glass, and aluminoborosilicate glass. The adapter 70 does not necessarily have to be made of a glass material, and may be made of other materials such as a resin material or a metal material. Examples of metal materials include a material having a thermal expansion coefficient of 5×10 －６ Kovar having a linear thermal expansion coefficient of 2×10 [ / K] or less may be selected. －６ Invar may be selected, which has a linear thermal expansion coefficient of less than [ / K].

[0036] The adapter 70 includes, for example, an upper surface 70a and a lower surface 70b facing the opposite side to the upper surface 70a. The upper surface 70a is an example of a "surface" in the present disclosure, and the lower surface 70b is an example of a "bottom surface" in the present disclosure. The upper surface 70a is aligned with the lower surface 70b along a normal direction of the lower surface 70b. The upper surface 70a is aligned parallel to the lower surface 70b, for example. The upper surface 70a faces the lower surface 60a of the optical connector 50. The lower surface 70b faces the main surface 30a of the optical IC substrate 30. The lower surface 70b is placed on the main surface 30a and fixed to the main surface 30a with, for example, an ultraviolet-curing adhesive.

[0037] A pair of through holes 73 are formed in the upper surface 70a. The pair of through holes 73 are guide holes into which the pair of guide pins 63 are respectively inserted, and are an example of a "recess" in the present disclosure. As shown in FIG. 2B, the pair of through holes 73 are formed at a pair of positions spaced apart from each other on the upper surface 70a. As shown in FIG. 2A, each through hole 73 penetrates from the upper surface 70a to the lower surface 70b. For example, each through hole 73 extends linearly from the upper surface 70a to the lower surface 70b along the normal direction of the upper surface 70a. The direction in which the central axis of each through hole 73 extends is, for example, perpendicular to the upper surface 70a.

[0038] Each guide pin 63 protruding from the lower surface 60a of the optical connector 50 is inserted into each through hole 73. By inserting each guide pin 63 into each through hole 73, the adapter 70 and the optical connector 50 are positioned relative to each other. Communication light of each optical fiber 500 emitted from the lower surface 60a of the optical connector 50 is incident on the upper surface 70a of the adapter 70. The communication light incident on the upper surface 70a passes through the adapter 70 and enters each optical IC 31 on the optical IC substrate 30 from the lower surface 70b of the adapter 70. In this way, each optical fiber 500 is optically connected to each optical IC 31.

[0039] Each through-hole 73 formed in the adapter 70 is formed, for example, using a process combining photolithography and dry etching such as RIE, or a laser-based hole-drilling technique. However, any glass hole-drilling technique can be used as long as the position of each through-hole 73 has an error of 1 μm or less from the predetermined design position and the inner diameter of each through-hole 73 can be within ±1 μm of the target inner diameter. Each through-hole 73 formed in the adapter 70 does not have to be perpendicular to the top surface 70 a of the adapter 70. For example, each through-hole 73 may be formed so as to be inclined, for example, by 8 degrees with respect to the normal direction of the top surface 70 a of the adapter 70. In this case, reflected light can be effectively reduced.

[0040] Next, an example of a method for mounting the adapter 70 on the optical IC substrate 30 will be described.

[0041] 3A , an adapter 70 including an upper surface 70a in which a pair of through holes 73 are formed, and an optical IC substrate 30 including a main surface 30a on which a plurality of optical ICs 31 are mounted are prepared. A lower surface 70b of the adapter 70 is fixed to the main surface 30a of the optical IC substrate 30. In this state, a portion of the main surface 30a of the optical IC substrate 30 is exposed from each of the through holes 73. Each of the optical ICs 31 mounted on the main surface 30a is disposed, for example, at a position away from each of the through holes 73 and is covered by the lower surface 70b of the adapter 70.

[0042] Next, as shown in FIG. 3B , with the lower surface 70b of the adapter 70 placed on the main surface 30a of the optical IC substrate 30, an embedding member P is embedded in each of the through holes 73. Here, the adapter 70 in a state in which the embedding member P is embedded in each of the through holes 73 is referred to as an "intermediate component 700." The intermediate component 700 is a component obtained during the mounting process of the adapter 70, and includes the adapter 70 and the embedding member P embedded in each of the through holes 73 of the adapter 70. The adapter 70 does not necessarily need to be fixed to the optical IC substrate 30, and may be independent of the optical IC substrate 30.

[0043] The embedding member P is a temporary protective member that temporarily protects the through hole 73 from fluids such as cleaning fluids, residues, and molding resin that may occur during the semiconductor mounting process. The embedding member P is embedded in the through hole 73 in a state that allows it to be removed from the through hole 73. By temporarily embedding the embedding member P in the through hole 73 in this manner, it prevents fluids from flowing into the through hole 73. The state in which the embedding member P is removable from the through hole 73 refers to a state in which the embedding member P can be physically or chemically removed from the through hole 73, and does not include a state in which the embedding member P is fixed to the inner surface of the through hole 73 to an extent that it cannot be removed from the through hole 73. The state in which the embedding member P has been removed refers to a state in which all or most of the embedding member P has been removed from the through hole 73 to an extent that it does not affect the positioning accuracy of the optical connector 50 relative to the adapter 70 when inserting the guide pin 63 into the through hole 73. Therefore, as long as the effect on the positioning accuracy of the optical connector 50 relative to the adapter 70 is negligible, it is not necessary for the entire embedding member P to be completely removed from the through hole 73, and a small portion of the embedding member P may remain in the through hole 73. The embedding member P being embedded in the through hole 73 means that at least a portion of the embedding member P is housed in the through hole 73.

[0044] The embedding member P is formed, for example, from a dissolving material that dissolves upon contact with a specific solvent. The specific solvent is, for example, a water-soluble solvent that dissolves in water. The water-soluble solvent may be, for example, a solvent used in a cleaning process performed during a semiconductor mounting process. The dissolving material is, for example, a water-soluble resin that dissolves in water. The water-soluble resin is typically a resin that dissolves at a rate of 0.1 g or more per 100 g of water at 25°C. Examples of water-soluble resins that can be used include sugar chain derivatives and cellulose compounds. The ease of solubility of a compound in water is proportional to the concentration of hydroxyl groups contained in the water-soluble resin. Hydroxyl groups are polar functional groups that form hydrogen bonds with water. The higher the concentration of hydroxyl groups, the more easily the material containing those hydroxyl groups dissolves in water. As the material for the embedding member P, a compound with an appropriate concentration of hydroxyl groups may be used, taking into account the subsequent cleaning process.

[0045] The material of the embedding member P may be a water-soluble resin used to protect the surface of a wafer in semiconductor processes such as dicing and laser processing. Examples of such water-soluble resins include "HOGOMAX" (trade name, manufactured by Disco Corporation), or "OFR-5" and "OBC" (trade names, manufactured by Tokyo Ohka Kogyo Co., Ltd.). The embedding member P may be a non-soluble material that does not dissolve in water. The non-soluble material may be, for example, a fluororesin (Teflon (registered trademark)). In this case, the embedding member P may be embedded in each through hole 73 by fitting the embedding member P into each through hole 73. In this case, since the process of removing the embedding member P from each through hole 73 is expected to be complicated, a soluble material may be used as the material of the embedding member P to avoid this process complexity.

[0046] When embedding the embedding member P in each through hole 73, for example, a liquid material of the embedding member P is injected into each through hole 73, thereby embedding the embedding member P in at least a portion of each through hole 73. Embedding the embedding member P in at least a portion of the through hole 73 means that the embedding member P is disposed in a part or all of the internal space surrounded by the inner surface of the through hole 73. For example, the embedding member P may be disposed without gaps in at least a portion of the through hole 73. The embedding member P may be filled in at least a portion of the through hole 73. The embedding member P may be disposed in the internal space of the through hole 73 so as to form a gap with respect to the inner surface of the through hole 73.

[0047] The through hole 73 accommodates the entire embedding member P. The surface Pa of the embedding member P is located at the same height as the upper surface 70a or at a lower height than the upper surface 70a. The embedding member P may be embedded in more than half of the internal space of the through hole 73, or may be embedded in the entire internal space of the through hole 73. In other words, the ratio of the volume of the embedding member P to the volume of the internal space of the through hole 73 may be 50% or more and 100% or less. The upper limit of the ratio of the volume of the embedding member P to the volume of the internal space of the through hole 73 may be, for example, 80% or more, or 90% or more.

[0048] Next, after a predetermined semiconductor mounting process is performed on the intermediate component 700 with the embedding material P embedded in each through hole 73, the embedding material P is dissolved in the water-soluble solvent by contacting the embedding material P with a water-soluble solvent. The predetermined semiconductor mounting process includes, for example, at least one of a cleaning process and a resin molding process. The cleaning process is a process of cleaning the intermediate component 700 and its surrounding components to remove impurities and the like from the intermediate component 700 and its surrounding components. The resin molding process is a process of covering the intermediate component 700 and its surrounding components with a molding resin to protect the intermediate component 700 and its surrounding components. After these processes, there is no risk of fluids such as cleaning liquid and molding resin flowing into each through hole 73, so there is no need to protect each through hole 73 with the embedding material P. Therefore, after performing such a semiconductor mounting process on the intermediate component 700, the embedding material P is dissolved to remove the embedding material P from each through hole 73.

[0049] 3C, the optical connector 50 is connected to the adapter 70 by inserting the guide pins 63 protruding from the optical connector 50 into the through holes 73 from which the embedding material P has been removed. This results in an optical connection assembly 100 (see FIG. 2A) in which the optical connector 50 is connected to the optical IC substrate 30 by the adapter 70.

[0050] The embedding material P is not limited to a water-soluble resin, and may be, for example, a positive resist that dissolves in an alkaline solution upon exposure. Examples of the positive resist include resin materials such as polyvinylphenol (PVP). Examples of the positive resist include chemically amplified resists that use a mixture of a polymer compound with a polarity conversion group introduced and a photoacid generator. Positive resists have high resistance to dry etching, making them suitable for protecting the through holes 73 during the semiconductor packaging process.

[0051] Positive resist is insoluble in alkaline solutions before exposure. However, after exposure, baking (heating) the positive resist generates acid, which diffuses within the resist and reacts with the acid-labile groups attached to the polymer chains of the resist. When the acid reacts with the acid-labile groups, the acid-labile groups are decomposed and converted back to their original hydroxyl groups. This chemical reaction locally increases the alkaline solubility of the resist. Then, an alkaline aqueous solution is used to selectively dissolve (remove) only the exposed portions of the resist. By utilizing these properties of the positive resist, the filler P can be removed from each through-hole 73 by exposure and baking when the protection of each through-hole 73 by the filler P is no longer necessary.

[0052] Next, a method for mounting the adapter 70 of this embodiment and the effects achieved by the intermediate part 700 of the adapter 70 will be described.

[0053] In this embodiment, even when processes such as a cleaning process and a resin molding process are performed during the semiconductor mounting process, the embedding member P embedded in at least a portion of the through hole 73 can prevent fluids such as cleaning liquid, residue, and molding resin from flowing into the through hole 73. Furthermore, by removing the embedding member P from the through hole 73, the through hole 73 can be made free of fluids. According to this method of temporarily embedding the embedding member P in at least a portion of the through hole 73, when connecting the optical connector 50 to the adapter 70, the guide pin 63 protruding from the optical connector 50 can be inserted into the through hole 73 without being obstructed by fluids remaining in the through hole 73. This allows for accurate positioning of the optical connector 50 relative to the adapter 70. As a result, optical loss between the optical connector 50 and the optical IC substrate 30 can be reduced.

[0054] As in the present embodiment, the embedding member P may be dissolved by contacting the solvent with the embedding member P. This method makes it possible to easily remove the embedding member P from the through-hole 73 while avoiding complicated processes, compared to a method in which the embedding member P is removed from the through-hole 73 without being dissolved.

[0055] As in the present embodiment, after intermediate part 700 is obtained, and before the embedding member P is removed from through hole 73, a process of cleaning intermediate part 700 with a cleaning liquid and a process of coating intermediate part 700 with molded resin layer M may be performed. During these processes, fluids are likely to flow into through hole 73. In contrast, in the present embodiment, even when these processes are performed, the embedding member P can prevent fluids from flowing into through hole 73, so the above-described effect can be effectively obtained.

[0056] As in the present embodiment, after intermediate part 700 is obtained, and before removing embedding material P from through hole 73, a step of covering intermediate part 700 with molded resin layer M and a step of polishing molded resin layer M to expose embedding material P may be performed. Even when intermediate part 700 is covered with molded resin layer M in this way, the embedding material P can be exposed by polishing molded resin layer M, and the exposed embedding material P can be easily removed from through hole 73.

[0057] As in the present embodiment, the through hole 73 may accommodate the entire embedding member P. The ratio of the volume of the embedding member P to the volume of the internal space of the through hole 73 may be 50% or more and 100% or less. In this case, the embedding member P can more reliably prevent fluids from flowing into the through hole 73, so that when connecting the optical connector 50 to the adapter 70, it is possible to more reliably avoid the fluids remaining in the through hole 73 from interfering with the insertion of the guide pin 63 into the through hole 73.

[0058] As in the present embodiment, the through-hole 73 may penetrate from the upper surface 70 a to the lower surface 70 b. In this case, the length of the guide pin 63 inserted into the through-hole 73 can be made as long as possible, so that when the guide pin 63 is inserted into the through-hole 73, the orientation of the optical connector 50 relative to the adapter 70 can be stabilized, and the optical connector 50 can be positioned relative to the adapter 70 with greater precision.

[0059] As in the present embodiment, the embedding member P may be formed of a dissolving material that dissolves in a solvent upon contact with the solvent. In this case, compared to removing the embedding member P from the through-hole 73 without dissolving it, it becomes possible to easily remove the embedding member P from the through-hole 73 while avoiding a complicated process.

[0060] As in the present embodiment, the dissolving material of the embedding material P may be a water-soluble resin that dissolves in a water-soluble solvent upon contact with the water-soluble solvent. In this case, by utilizing the water-soluble solvent used in the semiconductor mounting process, the embedding material P can be more easily removed from the through-hole 73 while avoiding complicating the process.

[0061] As in this embodiment, the intermediate component 700 may be formed from a material that transmits at least a portion of the wavelength range from ultraviolet light to visible light. In this case, the adapter 70 can be easily fixed to the optical IC board 30 using an ultraviolet-curing adhesive. Furthermore, when the embedding member P is to be dissolved in an alkaline solution by exposure to light, the embedding member P can be easily exposed to light.

[0062] In this embodiment, the dissolving material of the embedding material P may be a positive resist that dissolves in an alkaline solution upon exposure to light. In this case, the embedding material P can be more easily removed from the through-hole 73 by using exposure equipment and an alkaline solution that are used in the semiconductor mounting process.

[0063] The mounting method of the optical connecting component and the intermediate component of the optical connecting component of the present disclosure are not limited to the above-described embodiment. The mounting method of the optical connecting component and the intermediate component of the optical connecting component of the present disclosure may be modified in specific aspects within the scope of the claims.

[0064] 4 , a plurality of optical waveguides 700a are formed in an adapter 70A. The optical waveguides 700a are formed at positions away from the respective through holes 73 of the adapter 70A, are aligned in a row corresponding to the respective optical fibers 500, and extend from the upper surface 70a to the lower surface 70b. Each optical waveguide 700a exposed from the upper surface 70a faces a respective optical fiber 500 and is optically connected to the respective optical fiber 500. Each optical waveguide 700a exposed from the lower surface 70b faces a respective optical IC 31 and is optically connected to the respective optical IC 31.

[0065] Each optical waveguide 700a extends, for example, in a direction perpendicular to the upper surface 70a. For example, each optical waveguide 700a extends linearly from the upper surface 70a to the lower surface 70b along the normal direction to the upper surface 70a. Each optical waveguide 700a may extend in a direction inclined with respect to the normal direction to the upper surface 70a. The axial direction A1 in which the central axis of each optical waveguide 700a extends is, for example, parallel to the axial direction A2 in which the central axis of each through hole 73 extends. The central axis of each optical waveguide 700a is an axis passing through the center of each optical waveguide 700a. The axial direction A1 of each optical waveguide 700a may be inclined with respect to the axial direction A2 of each through hole 73. The angle of the axial direction A1 of each optical waveguide 700a with respect to the axial direction A2 of each through hole 73 may be, for example, greater than or equal to 0 degrees and less than or equal to 1 degree.

[0066] In the optical connection assembly 100A, a molded resin layer M is formed to cover the principal surface 30a of the optical IC substrate 30 and the periphery of the adapter 70A. The molded resin layer M is used to protect the components mounted on the principal surface 30a. Examples of materials for the molded resin layer M include resin materials such as epoxy resin, polyurethane resin, silicone resin, and polyester resin. The height of the molded resin layer M from the principal surface 30a may be the same as the height of the adapter 70A from the principal surface 30a. In other words, the surface Ma of the molded resin layer M may be located on the same plane as the upper surface 70a of the adapter 70A. The molded resin layer M is formed on the principal surface 30a so as to surround the adapter 70A, and the upper surface 70a of the adapter 70A is exposed from the molded resin layer M.

[0067] 4 to the optical IC substrate 30, first, as shown in FIG. 5A, the lower surface 70b of the adapter 70A, on which a pair of through holes 73 and a plurality of optical waveguides 700a are formed, is fixed to the main surface 30a of the optical IC substrate 30. In this state, each optical waveguide 700a faces each optical IC 31 of the optical IC substrate 30 and is optically connected to each optical IC 31. An electronic component 80 is mounted on the main surface 30a at a position away from the adapter 70A.

[0068] Next, as shown in FIG. 5B , a liquid material for the embedding member P is injected into each through-hole 73 of the adapter 70A to obtain an intermediate part 700A, which is the adapter 70A with the embedding member P embedded in at least a portion of each through-hole 73. The intermediate part 700A includes the adapter 70A and the embedding member P embedded in at least a portion of each through-hole 73 of the adapter 70A. For example, the embedding member P is embedded without gaps in the entire internal space of each through-hole 73. In other words, the embedding member P fills the entire through-hole 73. In this case, the surface Pa of the embedding member P is located on the same plane as the upper surface 70a of the adapter 70A.

[0069] 5C , a molded resin layer M is formed to cover the adapter 70A and the electronic components 80. The molded resin layer M can be formed by pouring a liquid molded resin onto the main surface 30a of the optical IC substrate 30. In this state, the embedding members P embedded in the through holes 73 in the top surface 70a of the adapter 70A and the optical waveguides 700a exposed on the top surface 70a are covered by the molded resin layer M.

[0070] 6A , the molded resin layer M is polished to expose the upper surface 70a of the adapter 70A from the molded resin layer M. In this state, the surface Ma of the molded resin layer M is located on the same plane as the upper surface 70a. The molded resin layer M remains around the adapter 70A. By exposing the upper surface 70a from the molded resin layer M, the optical waveguides 700a and the embedding member P are also exposed from the molded resin layer M. Before or after the resin molding step, a cleaning step may be performed to remove impurities and the like from around the adapter 70A.

[0071] Next, as shown in FIG. 6B , the embedding member P exposed from the mold resin layer M is removed from each through-hole 73. For example, the embedding member P is dissolved in a water-soluble solvent by bringing the embedding member P into contact with the water-soluble solvent. Thereafter, the guide pins 63 protruding from the optical connector 50 are inserted into the through-holes 73 from which the embedding member P has been removed, thereby connecting the optical connector 50 to the adapter 70A. This provides an optical connection assembly 100A (see FIG. 4 ) in which the optical connector 50 is connected to the optical IC substrate 30 by the adapter 70A.

[0072] Even with this configuration, the same effects as those of the above-described embodiment can be obtained. Furthermore, even when the adapter 70A is covered with a molded resin layer M, the through holes 73 and the optical waveguides 700a can be exposed from the molded resin layer M by polishing the molded resin layer M to expose the top surface 70a of the adapter 70A. In this case, the effort required to expose the through holes 73 and the optical waveguides 700a from the molded resin layer M can be reduced compared to when the through holes 73 and the optical waveguides 700a are formed on separate surfaces. In this way, when the through holes 73 and the optical waveguides 700a are formed on the same top surface 70a, the relative positions of the through holes 73 and the optical waveguides 700a can be accurately maintained. Therefore, the through holes 73 can be used to position the optical connector 50 relative to the adapter 70A, and the optical waveguides 700a can be optically connected to the optical connector 50 with high precision. This reduces optical loss between the optical connector 50 and the optical waveguides 700a.

[0073] When the angle of the axial direction A1 of each optical waveguide 700a with respect to the axial direction A2 of each through hole 73 is 1 degree or less, as in the adapter 70A, the relative position of each through hole 73 exposed from the molded resin layer M and each optical waveguide 700a can be maintained with greater precision, so that each through hole 73 can be used to position the optical connector 50 with respect to the adapter 70A, and optical connection of each optical waveguide 700a to the optical connector 50 can be performed with greater precision. This makes it possible to more effectively reduce optical loss between the optical connector 50 and each optical waveguide 700a.

[0074] 7A and 7B , an opening 75 may be formed in the upper surface 70a of the adapter 70B in addition to the pair of through holes 73. In this case, the adapter 70B is formed of a material that is not optically transparent to the communication light from the optical fiber 500. The material of the adapter 70B may be, for example, a resin material or a metal material. The opening 75 is located on the upper surface 70a of the adapter 70B at a position away from the through holes 73. The opening 75 penetrates from the upper surface 70a to the lower surface 70b, exposing the multiple optical ICs 31 mounted on the main surface 30a. The opening 75 forms a space for transmitting communication light between the multiple optical ICs 31 and the multiple optical fibers 500. During the installation of the adapter 70B, the opening 75 may also be filled with a filling material, similar to the pair of through holes 73. Even with this configuration, the same effects as those of the above-described embodiment can be obtained.

[0075] 8A and 8B , an optical connector 50A may be connected to a side surface 70c of an adapter 70C. In this case, a pair of guide pins 63A protruding from a tip surface 60c of a ferrule 60A of the optical connector 50A are inserted into a pair of blind holes 73A formed in the side surface 70c of the adapter 70C. Each blind hole 73A is a recess that does not penetrate the adapter 70C and extends from the side surface 70c of the adapter 70C toward an opposite side surface 70d. The side surface 70d is an inclined surface that is inclined toward both the side surface 70c and the main surface 30a.

[0076] As shown in FIG. 8B , the adapter 70C has a plurality of optical waveguides 700b formed therein. Each optical waveguide 700b extends from the side surface 70c toward the side surface 70d. The first ends 700c of the optical waveguides 700b exposed at the side surface 70c are aligned to face the optical fibers 500 of the optical connector 50 and are optically connected to the optical fibers 500. The second ends 700d of the optical waveguides 700b facing the side surface 70d are aligned to face the optical ICs 31 and are optically connected to the optical ICs 31. Communication light emitted from each optical fiber 500 propagates through each optical waveguide 700b and enters the side surface 70d. The communication light incident on the side surface 70d is reflected by the side surface 70d toward the optical ICs 31 and enters the optical ICs 31. Even with this configuration, the same effects as those of the above-described embodiment can be achieved.

[0077] <Modification 4> As shown in FIG. 9 , an optical connection assembly 100D may have a pair of non-through holes 73B formed in the top surface 70a of an adapter 70D instead of the pair of through holes 73. Each non-through hole 73B is a recess that does not penetrate the adapter 70D and extends from the top surface 70a to a position short of the bottom surface 70b. In this case, the bottom surface of each non-through hole 73B is located in a region close to the top surface 70a and away from the bottom surface 70b. For example, each non-through hole 73B extends in a direction perpendicular to the top surface 70a. However, each non-through hole 73B may extend in a direction inclined from the direction perpendicular to the top surface 70a. A guide pin 63B protruding from the optical connector 50 is inserted into each non-through hole 73B.

[0078] Even with this configuration, the same effects as those of the above-described embodiment can be obtained. When such a pair of non-through holes 73B is formed in the adapter 70D, it is possible to prevent the adhesive that fixes the lower surface 70b of the adapter 70 to the main surface 30a of the optical IC substrate 30 from flowing from the lower surface 70b of the adapter 70 into each of the non-through holes 73B, thereby more reliably preventing fluids from flowing into each of the non-through holes 73B.

[0079] The present disclosure is not limited to the above-described embodiment and each modified example, and various other modifications are possible. For example, the above-described embodiment and each modified example may be combined with each other to a consistent extent depending on the required purpose and effect. In the above-described embodiment and each modified example, the "recess" of the present disclosure is illustrated as a through hole 73 or a non-through hole 73A. The "recess" of the present disclosure is not limited to a hole, and may be a groove or the like, as long as it has a shape that can form a space to accommodate a "protrusion protruding from the optical waveguide component." In the above-described embodiment and each modified example, the "protrusion" of the present disclosure is illustrated as a guide pin 63 separate from the ferrule 60. The "protrusion" of the present disclosure may be a protrusion formed integrally with the ferrule 60.

[0080] DESCRIPTION OF SYMBOLS 10...Optical communication module 15...Substrate 20...Communication LSI 25...Electrical wiring 30...Optical IC substrate (circuit board) 30a...Main surface 31...Optical IC 50, 50A...Optical connector (optical waveguide component) 60, 60A...Ferrule 60a...Bottom surface 60b...Side surface 60c...Tip surface 63, 63A, 63B...Guide pin (convex portion) 70, 70A, 70B, 70C, 70D...Adapter (optical connection component) 70a...Top surface (surface) 70b...Bottom surface (bottom surface) 70c, 70d...Side surface 73...Through hole (recess) 73A, 73B...Non-through hole (recess) 75...Opening 80...Electronic component 100, 100A, 100C, 100D...Optical connection assembly 500...Optical fiber 700, 700A...Intermediate part 700a, 700b...Optical waveguide 700c...First end 700d...Second end A1...Axial direction A2...Axis direction M...Mold resin layer Ma...Surface P...Embedded member Pa...Surface

Claims

1. A method for mounting an optical connecting component that connects an optical waveguide component to a circuit board, comprising the steps of: preparing the optical connecting component having a bottom surface that can be placed on a main surface of the circuit board, a surface different from the bottom surface, and a recess formed in the surface; placing the bottom surface of the optical connecting component on the main surface of the circuit board and embedding an embedding member in at least a part of the recess, thereby obtaining the optical connecting component as an intermediate component, with the embedding member embedded in at least a part of the recess; removing the embedding member from the recess; and positioning the optical waveguide component with respect to the optical connecting component by inserting a convex portion protruding from the optical waveguide component into the recess from which the embedding member has been removed.

2. The method for mounting an optical connecting component according to claim 1, wherein in the step of removing the embedding material from the recess, the embedding material is dissolved by bringing a solvent into contact with the embedding material.

3. A method for mounting an optical connection component as described in claim 1 or claim 2, comprising at least one of the following steps: after obtaining the intermediate component and before removing the embedding member from the recess, cleaning the intermediate component with a cleaning liquid; and covering the intermediate component with a molded resin layer.

4. A method for mounting an optical connecting component as described in claim 3, comprising the steps of: after obtaining the intermediate component and before removing the embedding member from the recess, covering the intermediate component with the molded resin layer; and polishing the molded resin layer so that the embedding member is exposed from the molded resin layer.

5. An intermediate component for an optical connecting component obtained during a mounting process of an optical connecting component that connects an optical waveguide component to a circuit board, comprising: a bottom surface that can be placed on a main surface of the circuit board; a surface different from the bottom surface; a recess formed on the surface; and an embedding member that is embedded in at least a part of the recess and is removable from the recess.

6. An intermediate component for optical connecting components according to claim 5, wherein the recess accommodates the entirety of the embedding member, and the volume of the embedding member accounts for 50% or more and 100% or less of the volume of the internal space of the recess.

7. An intermediate component for optical connecting components according to claim 5 or claim 6, wherein the surface is aligned with the bottom surface in a direction intersecting the bottom surface, and the recesses are a pair of through holes that penetrate from the surface to the bottom surface.

8. An intermediate component for optical connecting components according to claim 5 or claim 6, wherein the surface is aligned with the bottom surface in a direction intersecting the bottom surface, and the recesses are a pair of blind holes extending from the surface to a position not reaching the bottom surface.

9. An intermediate part for optical connecting parts according to any one of claims 5 to 8, wherein the embedding member is formed from a dissolving material that dissolves in a solvent when it comes into contact with the solvent.

10. An intermediate component for optical connecting components according to claim 9, wherein the dissolving material is a water-soluble resin that dissolves in a water-soluble solvent upon contact with the water-soluble solvent.

11. The intermediate component of the optical connecting component according to claim 9, wherein the dissolvable material is a positive resist that dissolves in an alkaline solution upon exposure to light.

12. An intermediate part of an optical connecting part according to any one of claims 5 to 11, wherein the intermediate part is formed from a material that transmits at least a part of wavelengths in the wavelength range from ultraviolet light to visible light.

13. An intermediate part of an optical connecting part described in any one of claims 5 to 12, further comprising at least one optical waveguide exposed on the surface at a position different from the recess and extending from the surface to the bottom surface, the intermediate part being surrounded by a molded resin layer, and the surface being exposed from the molded resin layer.

14. An intermediate part for optical connecting parts according to claim 13, wherein the surface is aligned with the bottom surface along a direction intersecting the bottom surface, the optical waveguide and the recess extend in a straight line from the surface toward the bottom surface, and the angle between the direction in which the central axis of the recess extends and the direction in which the central axis of the optical waveguide extends is 1 degree or less.

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