Optical semiconductor device package and optical semiconductor device

Abstract

An optical semiconductor device package (2) is for sealing an optical semiconductor element (3) with a sealing resin (4), and comprises: a lead frame body (11); a first metal layer (12) covering the lead frame body (11); a resin frame body (20) provided on the first metal layer (12); and a second metal layer (13) partially provided at a location where the first metal layer (12) and the resin frame body (20) are joined. The surface of the second metal layer (13) is in contact with the resin frame body (20), and the surface roughness of the second metal layer (13) is higher than the surface roughness of the first metal layer (12).

Description

Package for optical semiconductor device and optical semiconductor device

[0001] The present disclosure relates to a package for an optical semiconductor device and an optical semiconductor device.

[0002] Conventionally, a package for an optical semiconductor device (packaging component for an optical semiconductor device) has been known that includes a lead frame and a resin frame provided on the lead frame (see, for example, Patent Document 1). The lead frame has a lead frame body and a metal layer provided on the lead frame body. The metal layer forms a surface layer of the lead frame, and the resin frame is bonded to this metal layer.

[0003] An optical semiconductor element such as an LED (Light Emitting Diode) is mounted in an optical semiconductor device package. For example, an optical semiconductor device using the optical semiconductor device package includes an optical semiconductor element mounted on a lead frame of the optical semiconductor device package and surrounded by a resin frame, and a sealing resin filled in the resin frame so as to cover the optical semiconductor element. An optical semiconductor device configured in this manner is a packaged surface-mounted mounting component and is used as a light source in various fields such as lighting, automobiles, and displays.

[0004] Japanese Patent Application Laid-Open No. 2006-222382

[0005] In optical semiconductor device packages, there is a problem with the adhesion between the metal layer, which is the surface layer of the lead frame, and the resin frame. If good adhesion is not obtained between the metal layer, which is the surface layer of the lead frame, and the resin frame, gaps may occur at the interface (joint) between the metal layer and the resin frame.

[0006] If a gap occurs at the interface between the metal layer of the lead frame and the resin frame, foreign matter such as gas or liquid can enter the resin frame through the gap, causing problems such as deterioration of the package for the optical semiconductor device and the components that make up the optical semiconductor device.

[0007] For example, in optical semiconductor device packages, a silver film is sometimes formed as a light-reflecting film on the outermost surface of the area surrounded by a resin frame (the area where the optical semiconductor element is mounted) to efficiently extract light from the optical semiconductor element. However, if a gap occurs at the interface between the metal layer of the lead frame and the resin frame and sulfides (such as hydrogen sulfide) penetrate into the resin frame through the gap, the silver constituting the silver film reacts with the sulfide, causing the silver film to blacken and reduce its light reflectance. This results in a decrease in the light-emitting efficiency and durability of the optical semiconductor device. In particular, when optical semiconductor devices are used in harsh environments such as automobiles, foreign matter such as gas or liquid easily penetrates into the resin frame, increasing the severity of the defects.

[0008] Furthermore, an optical semiconductor device in which an optical semiconductor element and sealing resin are provided in a package for the optical semiconductor device is solder-mounted to a mounting substrate using a solder material or the like. However, if a gap occurs at the interface between the metal layer of the lead frame and the resin frame, the heat of reflow during solder mounting may cause the solder material to seep through the gap and enter the resin frame.

[0009] The present disclosure has been made to solve such problems, and aims to provide a package for an optical semiconductor device, an optical semiconductor device, and the like that can prevent foreign matter such as sulfides or solder from entering a resin frame.

[0010] In order to achieve the above object, an optical semiconductor device package according to one aspect of the present disclosure is a package for an optical semiconductor device for encapsulating an optical semiconductor element with an encapsulating resin, the package comprising: a lead frame body, a first metal layer covering the lead frame body, a resin frame body provided on the first metal layer, and a second metal layer partially provided at a location where the first metal layer and the resin frame are joined. In this case, it is preferable that a surface of the second metal layer contacts the resin frame, and that the surface roughness of the second metal layer be higher than that of the first metal layer.

[0011] Furthermore, an optical semiconductor device according to one embodiment of the present disclosure includes the above-described package for an optical semiconductor device, an optical semiconductor element located on the first metal layer and surrounded by the resin frame, and a sealing resin provided within the resin frame and sealing the optical semiconductor element.

[0012] According to the present disclosure, it is possible to prevent foreign matter such as sulfides or solder from entering the resin frame.

[0013] Fig. 1 is a diagram showing the configuration of an optical semiconductor device according to an embodiment. Fig. 2 is a surface SEM image of a second metal layer in an optical semiconductor device package according to an embodiment. Fig. 3 is a cross-sectional SEM image of a region near the boundary between the second metal layer and a resin frame in an optical semiconductor device package according to an embodiment. Fig. 4 is a diagram for explaining a method for manufacturing an optical semiconductor device package according to an embodiment. Fig. 5 is a diagram showing the configuration of an optical semiconductor device according to a modified example.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each embodiment shown here represents a specific example of the present disclosure. Therefore, the numerical values, shapes, components, arrangement and connection of the components, steps (processes), and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the superordinate concept of the present disclosure will be described as optional components.

[0015] Furthermore, each drawing is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each drawing. In each drawing, the same reference numerals are used to denote substantially the same components, and redundant explanations will be omitted or simplified.

[0016] Furthermore, in this specification, the terms "above," "upper," "below," and "belower" in the configuration of an optical semiconductor device do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are terms defined by a relative positional relationship based on the stacking order in a stacked structure. Furthermore, the terms "above" and "below" are applied not only to a case where two components are arranged with a gap between them and another component exists between the two components, but also to a case where two components are arranged closely to each other and the two components are in contact with each other.

[0017] In this specification, optical semiconductor devices such as light-emitting elements such as LEDs and light-receiving elements such as photodiodes are referred to as "optical semiconductor elements," the package itself for mounting the optical semiconductor elements is referred to as "package for optical semiconductor device," and the entire package for optical semiconductor device in which the optical semiconductor elements are mounted (the combination of the optical semiconductor element and the package for optical semiconductor device) is referred to as "optical semiconductor device."

[0018] (Embodiment) [Configuration of Optical Semiconductor Device and Package for Optical Semiconductor Device] First, the configuration of an optical semiconductor device 1 and an optical semiconductor device package 2 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of an optical semiconductor device 1 according to an embodiment. Fig. 1(a) is a plan view of the optical semiconductor device 1, and Fig. 1(b) is a cross-sectional view taken along line b-b in Fig. 1(a). Note that in Fig. 1, the porous holes of the second metal layer 13 and the third metal layer 14 are shown schematically.

[0019] As shown in FIG. 1 , an optical semiconductor device 1 according to this embodiment includes a package 2 for an optical semiconductor device, an optical semiconductor element 3 mounted in the package 2 for an optical semiconductor device, and a sealing resin 4 filled in the package 2 for an optical semiconductor device so as to cover the optical semiconductor element 3.

[0020] The optical semiconductor device package 2 is a package for mounting an optical semiconductor element 3. The optical semiconductor device package 2 is a package for sealing the optical semiconductor element 3 with sealing resin 4, and includes a lead frame 10 and a resin frame 20 provided on the lead frame 10. The sealing resin 4 is filled in the area surrounded by the resin frame 20.

[0021] The portion of the lead frame 10 outside the resin frame 20 is an outer lead portion, which serves as a soldering portion 10 a. The soldering portion 10 a is a portion to which a solder material is applied and which is soldered to the wiring of the mounting substrate when the optical semiconductor device 1 is mounted on the mounting substrate or the like.

[0022] On the other hand, the portion of the lead frame 10 inside the resin frame 20 is an inner lead portion, which is an optical semiconductor element mounting portion 10b on which the optical semiconductor element 3 is mounted. In other words, the resin frame 20 surrounds the optical semiconductor element mounting portion 10b of the lead frame 10.

[0023] The lead frame 10 has a lead frame body 11 , a first metal layer 12 , a second metal layer 13 , and a third metal layer 14 .

[0024] The lead frame body 11 is a rigid body having electrical conductivity. The lead frame body 11 is a metal substrate made of a metal material such as copper, iron, nickel, aluminum, or an alloy containing at least one or two of these. In this embodiment, the lead frame body 11 is made of copper. The thickness of the lead frame body 11 is, for example, 0.1 mm to 0.3 mm, but is not limited to this.

[0025] The lead frame body 11 is separated into a first lead frame body 11a and a second lead frame body 11b via a gap G. A resin portion 30 made of a resin material is provided in the gap G. The resin portion 30 is an insulating layer made of an insulating resin material and is embedded in the gap G. The first lead frame body 11a and the second lead frame body 11b are electrically insulated and separated by this resin portion 30. The resin material making up the resin portion 30 is the same as the resin material making up the resin frame body 20. The resin portion 30 is formed when the resin frame body 20 is molded. In other words, the resin frame body 20 and the resin portion 30 are formed simultaneously.

[0026] The first metal layer 12 covers the lead frame body 11. In the present embodiment, the first metal layer 12 covers the entire surface of the lead frame body 11. Specifically, the first metal layer 12 covers the entire surface of each of the first lead frame body 11a and the second lead frame body 11b. Therefore, the first metal layer 12 is formed on the upper surface, lower surface, and side surface of each of the first lead frame body 11a and the second lead frame body 11b. The first metal layer 12 is, for example, a plating film formed by a plating method using the lead frame body 11 made of copper as a base material.

[0027] The first metal layer 12 may be a single metal layer formed of a single metal film, or may be a metal layer group formed by stacking multiple metal films. When the first metal layer 12 is a metal layer group, the multiple metal films forming the first metal layer 12 may include a silver film formed of silver. In this case, the silver film may be the outermost surface film of the first metal layer 12. This allows the silver film to reflect light emitted by the optical semiconductor element 3 when a light-emitting element such as an LED chip is mounted on the optical semiconductor device package 2, thereby improving the utilization efficiency of the light emitted by the optical semiconductor element 3. Therefore, the light emitted by the optical semiconductor element 3 can be efficiently extracted from the optical semiconductor device package 2.

[0028] Furthermore, when the first metal layer 12 is a group of metal layers, the multiple metal films constituting the first metal layer 12 may include, in addition to the first metal film which is a silver film, a second metal film which is made of nickel, palladium, gold, or an alloy containing these.

[0029] Table 1 below shows an example of one or more metal films constituting the first metal layer 12 and their film thicknesses. The first metal layers 12 in Table 1 are all plated films formed on the lead frame body 11 made of copper as a base material. The plated films can be formed by electrolytic plating or the like. Regarding the layer structure of the first metal layer 12 in Table 1, when the first metal layer 12 is composed of multiple metal films, the metal shown on the far left is the metal that constitutes the bottommost metal film of the first metal layer 12, and the metal shown on the far right is the metal that constitutes the topmost metal film of the first metal layer 12.

[0030]

[0031] 1B, a second metal layer 13 and a third metal layer 14 are provided on the first metal layer 12. The second metal layer 13 and the third metal layer 14 are partially provided on the first metal layer 12. Each of the second metal layer 13 and the third metal layer 14 has a porous shape. Details of the second metal layer 13 and the third metal layer 14 will be described later.

[0032] A resin frame 20 is provided on the lead frame 10. The resin frame 20 is provided on the first metal layer 12 of the lead frame 10. The resin frame 20 is bonded to the first metal layer 12. The resin frame 20 is a rectangular annular frame in top view. In other words, the resin frame 20 surrounds the optical semiconductor element 3 in top view.

[0033] In this embodiment, the optical semiconductor element 3 is a light-emitting element that emits light. Therefore, the resin frame 20 constitutes a reflector that reflects the light emitted from the optical semiconductor element 3 toward the outside. Specifically, the resin frame 20 has a wall portion with an inclined inner surface, and the opening width of the resin frame 20 becomes larger toward the upper side. This allows the light emitted from the optical semiconductor element 3 to be reflected by the inner surface of the resin frame 20 and emitted upward.

[0034] The resin frame 20 is made of a white resin material to reflect light on its surface. Specifically, the resin frame 20 contains a white pigment. In this embodiment, the resin frame 20 contains a mineral filler or glass fiber as a reinforcing material, and titanium oxide (TiO ２ The mineral filler may be a silica-based inorganic material having a filler diameter of 2 μm to 20 μm, but is not particularly limited thereto. The glass fiber may be a silica-based inorganic material having a filler diameter of 50 μm to 100 μm, but is not particularly limited thereto.

[0035] Various base resins can be used to form the resin frame 20. As an example, the base resin to form the resin frame 20 may be a thermoplastic resin such as PPA (polyphthalamide), LCP (liquid crystal polymer), PCT (polycyclohexyldimethylene terephthalate), UP (unsaturated polyester), or PP (polypropylene), or a thermosetting resin such as epoxy resin, silicone resin, polyimide resin, or acrylic resin.

[0036] An optical semiconductor element 3 is placed in a recess defined by the resin frame 20 and lead frame 10 in the optical semiconductor device package 2. The optical semiconductor element 3 is located on the first metal layer 12 of the optical semiconductor device package 2 and is surrounded by the resin frame 20. In this embodiment, the optical semiconductor element 3 is a light-emitting element. Specifically, the optical semiconductor element 3 is an LED chip. The LED chip is an example of a semiconductor light-emitting element that emits light using a predetermined DC power, and is a bare chip that emits monochromatic visible light.

[0037] The optical semiconductor element 3 is mounted on the lead frame 10 within the resin frame 20. Specifically, the optical semiconductor element 3 is die-bonded to a predetermined position on the optical semiconductor element mounting portion 10b of the lead frame 10 via a die-bonding material 5. The optical semiconductor element 3 is wire-bonded using a wire 6 such as a gold wire. In this embodiment, the optical semiconductor element 3 is a double-sided electrode type LED chip, and therefore a single wire 6 is connected to the top electrode of the optical semiconductor element 3. That is, the top electrode of the optical semiconductor element 3 is electrically connected to the first electrode portion of the lead frame 10 via the wire 6. Meanwhile, the bottom electrode (back electrode) of the optical semiconductor element 3 is electrically connected to the second electrode portion of the lead frame 10 via the conductive die-bonding material 5. The first electrode portion of the lead frame 10 is part of the first metal layer 12 in the first lead frame main body 11a. The second electrode portion of the lead frame 10 is part of the first metal layer 12 in the second lead frame main body 11b.

[0038] The sealing resin 4 is provided inside the resin frame 20 of the optical semiconductor device package 2 and seals the optical semiconductor element 3. The sealing resin 4 is a sealing member for sealing the optical semiconductor element 3. The sealing resin 4 is filled inside the resin frame 20 so as to cover the optical semiconductor element 3 mounted inside the resin frame 20.

[0039] The sealing resin 4 is made of a light-transmitting resin material such as silicone resin. Furthermore, when the optical semiconductor element 3 is a blue LED chip that emits blue light, the sealing resin 4 may contain a yellow phosphor such as YAG (yttrium aluminum garnet) that emits fluorescence using the blue light from the blue LED chip as excitation light, in order to emit white light from the optical semiconductor device 1. Alternatively, the sealing resin 4 may not contain a phosphor and remain transparent.

[0040] The optical semiconductor device 1 configured in this manner can be mounted on a mounting board by soldering the soldering portion 10a of the lead frame 10 to the wiring of the mounting board using a soldering material such as cream solder.

[0041] Here, the detailed configurations of the second metal layer 13 and the third metal layer 14 in the lead frame 10 will be described.

[0042] The second metal layer 13 and the third metal layer 14 are both provided on the surface of the first metal layer 12, but are provided at different locations on the first metal layer 12.

[0043] First, the second metal layer 13 is provided in a portion of the first metal layer 12 where the resin frame 20 is formed. In other words, the second metal layer 13 is provided below the resin frame 20. Specifically, the second metal layer 13 is provided directly below the resin frame 20, and is provided in a portion where the first metal layer 12 and the resin frame 20 are joined. The surface of the second metal layer 13 is in contact with the resin frame 20.

[0044] In this embodiment, the second metal layer 13 is not provided over the entire area where the first metal layer 12 and the resin frame 20 are joined, but is provided only partially at the area where the first metal layer 12 and the resin frame 20 are joined. In other words, the second metal layer 13 is provided only partially at the area where the first metal layer 12 and the resin frame 20 are joined, and is not provided on the outside or inside of the resin frame 20. Therefore, the second metal layer 13 overlaps with the resin frame 20 in the vertical direction, but is not exposed from the resin frame 20 in top view. For this reason, the second metal layer 13 does not protrude outside the resin frame 20, nor does it protrude inside the resin frame 20.

[0045] 1(b), the width of the second metal layer 13 is preferably 50% or more and less than 100% of the width of the resin frame 20 at the location where the first metal layer 12 and the resin frame 20 are joined. Furthermore, the width of the second metal layer 13 is preferably 80% or more of the width of the resin frame 20.

[0046] The region surrounded by a dashed line in Fig. 1A indicates the region where the second metal layer 13 is provided. As shown in the dashed line region in Fig. 1A, at the location where the first metal layer 12 and the resin frame 20 are joined, the area of ​​the surface of the second metal layer 13 facing the resin frame 20 is preferably 50% or more and less than 100% of the area of ​​the underside of the resin frame 20 (the surface facing the first metal layer 12). In other words, the area ratio of the second metal layer 13 to the underside of the resin frame 20 is preferably 50% or more and less than 100%. This can improve the adhesion between the second metal layer 13 and the resin frame 20.

[0047] On the other hand, the third metal layer 14 is provided on the first metal layer 12 covering the side surface of the lead frame body 11. Specifically, the third metal layer 14 is provided on each of the first metal layer 12 covering the side surface of the first lead frame body 11a facing the gap G and the first metal layer 12 covering the side surface of the second lead frame body 11b facing the gap G. The surface of the third metal layer 14 is in contact with the resin part 30.

[0048] The third metal layer 14 provided on the first lead frame body 11a may be provided on the entire surface of the first metal layer 12 covering the side surface of the first lead frame body 11a on the gap G side, or may be provided only on a portion (i.e., partial) of the first metal layer 12 covering the side surface of the first lead frame body 11a on the gap G side. Similarly, the third metal layer 14 provided on the second lead frame body 11b may be provided on the entire surface of the first metal layer 12 covering the side surface of the second lead frame body 11b on the gap G side, or may be provided only on a portion (i.e., partial) of the first metal layer 12 covering the side surface of the second lead frame body 11b on the gap G side.

[0049] The area of ​​the third metal layer 14 provided on the first lead frame body 11a on the first metal layer 12 side is preferably 50% to 100% of the area of ​​the first metal layer 12 covering the side surface of the first lead frame body 11a on the gap G side. In other words, the area ratio of the third metal layer 14 provided on the first lead frame body 11a to the first metal layer 12 covering the side surface of the first lead frame body 11a on the gap G side is preferably 50% to 100%. This improves adhesion between the third metal layer 14 and the resin portion 30. Similarly, the area of ​​the third metal layer 14 provided on the second lead frame body 11b on the first metal layer 12 side is preferably 50% to 100% of the area of ​​the first metal layer 12 covering the side surface of the second lead frame body 11b on the gap G side. In other words, the area ratio of the third metal layer 14 provided on the second lead frame body 11b to the first metal layer 12 covering the side surface of the second lead frame body 11b on the gap G side is preferably 50% to 100%. This can improve the adhesion between the third metal layer 14 and the resin part 30 .

[0050] The second metal layer 13 and the third metal layer 14 have a porous shape. In other words, the second metal layer 13 and the third metal layer 14 are not smooth metal layers, but porous metal layers with countless pores on their surfaces. Therefore, the surface roughness of the second metal layer 13 and the third metal layer 14 is high. Specifically, the surface roughness of the second metal layer 13 and the surface roughness of the third metal layer 14 are both higher than the surface roughness of the first metal layer 12. The second metal layer 13 and the third metal layer 14 are formed simultaneously. Therefore, the porous shape of the second metal layer 13 and the porous shape of the third metal layer 14 are the same. In other words, the surface roughness of the second metal layer 13 and the surface roughness of the third metal layer 14 are the same.

[0051] In this embodiment, the second metal layer 13 and the third metal layer 14, which have a porous shape, are both nickel metal layers made of nickel. Specifically, the second metal layer 13 and the third metal layer 14 are nickel metal layers formed into a porous shape. In other words, the second metal layer 13 and the third metal layer 14 are nickel metal layers whose entire layers are porous.

[0052] Furthermore, the second metal layer 13 and the third metal layer 14 having a porous shape may be metal plating films formed by a plating method. Therefore, the nickel metal layers (second metal layer 13 and third metal layer 14) having a porous shape may be nickel plating films formed by nickel plating. Specifically, the second metal layer 13 and the third metal layer 14 are nickel plating films in which the entire layer is porous. This nickel plating film may have a nickel purity of 99% or more. The nickel plating film having a porous shape can be formed by an electrolytic nickel plating method.

[0053] Although it is possible to form a flat nickel plating film using electroless nickel plating, it is difficult to form a nickel plating film with a porous structure using electroless nickel plating. Because electroless nickel plating is a plating method that uses a chemical reaction based on oxidation-reduction, the plating bath contains reducing agents such as phosphorus and boron. Therefore, when a nickel plating film is formed using electroless nickel plating, precipitation is initiated by the action of these reducing agents, and the nickel coating contains 1% or more of phosphorus or boron at the time of deposition. In other words, the chemical reaction does not begin unless phosphorus or boron is precipitated. Therefore, with electroless nickel plating, phosphorus, boron, etc. are preferentially precipitated in the nickel metal, making it difficult to form a nickel plating film with a porous structure.

[0054] At the location where the first metal layer 12 and the resin frame 20 are bonded, a portion of the resin frame 20 is embedded in a porous hole (porous pore) in the second metal layer 13 provided on the first metal layer 12. In this way, a portion of the resin frame 20 enters the porous pore of the second metal layer 13, thereby creating an anchor effect that firmly bonds the resin frame 20 and the second metal layer 13. This improves the adhesion between the first metal layer 12 and the resin frame 20, thereby preventing gaps from forming on the underside of the resin frame 20 (the surface on the first metal layer 12 side).

[0055] Furthermore, on the side surface of the lead frame body 11, a portion of the resin portion 30 is embedded in the porous holes (porous pores) in the third metal layer 14. In this way, a portion of the resin portion 30 enters the porous pores in the third metal layer 14, thereby creating an anchor effect that firmly bonds the resin portion 30 and the third metal layer 14. This improves the adhesion between the first metal layer 12 and the resin portion 30 on the side surface of the lead frame body 11, thereby preventing gaps from forming between the first metal layer 12 and the resin portion 30.

[0056] Here, the porous shape, porous diameter, porous depth, number of porous holes, and porous surface area of ​​the second metal layer 13 and the third metal layer 14 will be described below.

[0057] [Porous Shape] The porous shapes of the second metal layer 13 and the third metal layer 14 are shapes in which a plurality of holes are formed in the metal films constituting the second metal layer 13 and the third metal layer 14. As shown in Fig. 2, the plurality of holes in the porous shape of the second metal layer 13 are randomly distributed in two dimensions when viewed from above. Fig. 2 is an SEM image of the surface of the second metal layer 13 in the optical semiconductor device package 2 according to the embodiment. Note that the plurality of holes in the porous shape of the third metal layer 14 are also randomly distributed in two dimensions when viewed from above.

[0058] Furthermore, each of the porous holes in the second metal layer 13 and the third metal layer 14 may be a through-hole that penetrates the metal film, or a hole that does not penetrate the metal film and has a bottom halfway through the metal film. When each of the porous holes in the second metal layer 13 and the third metal layer 14 is a through-hole, the bottom surface of each of the porous holes in the second metal layer 13 and the third metal layer 14 is the surface of the first metal layer 12. In this case, the depth of the second metal layer 13 is the film thickness of the second metal layer 13. Similarly, the depth of the third metal layer 14 is the film thickness of the third metal layer 14.

[0059] 3 is a cross-sectional SEM image of the optical semiconductor device package 2 according to the embodiment, near the boundary between the second metal layer 13 and the resin frame 20. Each of the porous holes in the second metal layer 13 shown in FIG. 3 is a through-hole that penetrates the metal film.

[0060] Each of the porous holes in the second metal layer 13 and the third metal layer 14 is wider at the bottom than at the top. In other words, the porous holes have a narrow opening and a wider space toward the back. Specifically, when the second metal layer 13 is viewed from above, the area of ​​the porous holes increases from the planar surface of the second metal layer 13 downward. The same is true for the third metal layer 14.

[0061] As an example, for each porous hole in the second metal layer 13 and the third metal layer 14, the ratio of the top width of the hole to the bottom width of the hole in a cross-sectional view is preferably 1.3≦b / a≦4.0. If the ratio b / a exceeds 4.0, the strength of the porous sidewalls may be reduced, and the porous shape may not be maintained, from the perspective of the strength of the second metal layer 13 and the third metal layer 14. On the other hand, if the ratio b / a is less than 1.3, the anchoring effect caused by a portion of the resin frame 20 and a portion of the resin portion 30 entering the porous holes may not be fully achieved, and the adhesion between the second metal layer 13 and the resin frame 20 or the third metal layer 14 and the resin portion 30 may be reduced. Furthermore, for each porous hole in the second metal layer 13 and the third metal layer 14, the ratio of the bottom area to the top area of ​​the hole in a plan view is preferably 1.3 or more and 4.0 or less.

[0062] [Porous diameter] The porous second metal layer 13 and third metal layer 14 desirably have a porous diameter, which is the width of the upper part of the porous hole, of 0.05 μm or more and 2.0 μm or less, from the viewpoint of improving adhesion with the resin frame 20 or the resin part 30. The mineral filler contained in the resin frame 20 and the resin part 30 usually has a filler diameter of 2 μm or more and 20 μm or less. Therefore, if the porous diameter exceeds 2.0 μm, the mineral filler will easily enter the porous hole, impairing adhesion between the second metal layer 13 and the resin frame 20 or between the third metal layer 14 and the resin part 30. On the other hand, if the pore diameter is less than 0.05 μm, the fluidity of the base resin of the resin frame body 20 and the resin part 30 during molding will result in less penetration of the base resin into the porous holes, and a sufficient anchor effect will not be obtained, which may result in a decrease in adhesion between the second metal layer 13 and the resin frame body 20 and between the third metal layer 14 and the resin part 30.

[0063] [Porous Depth] The porous depth, which is the depth of each hole in the porous shape of the second metal layer 13 and the third metal layer 14, is preferably 0.2 μm or more and 2 μm or less. If the porous depth is less than 0.2 μm, the penetration of the base resin into the porous holes of the resin frame 20 and the resin portion 30 is reduced, resulting in an insufficient anchoring effect, and there is a risk of reduced adhesion between the second metal layer 13 and the resin frame 20 and between the third metal layer 14 and the resin portion 30. On the other hand, if the porous depth exceeds 2 μm, when the second metal layer 13 and the third metal layer 14 are formed by electrolytic nickel plating, stress in the nickel plating coating increases, making it difficult to form a porous shape, or the pore diameter cannot be maintained during nickel deposition, resulting in the ratio (b / a) falling below 1.3. As a result, there is a risk that a porous shape sufficient to ensure the anchoring effect cannot be formed.

[0064] [Number of Porous Holes] The number of porous holes (porous holes) in the second metal layer 13 and the third metal layer 14 should be 5 or more in an arbitrarily designated rectangular area of ​​10 μm × 10 μm when viewed in plan of the second metal layer 13 or the third metal layer 14. If the number of porous holes in the rectangular area of ​​10 μm × 10 μm is less than 5, a sufficient anchor effect cannot be obtained, and the adhesion between the second metal layer 13 and the resin frame 20 and the adhesion between the third metal layer 14 and the resin part 30 may be reduced.

[0065] On the other hand, the upper limit of the number of porous holes is not particularly limited as long as the above ratio (b / a) is 4.0 or less, but the number of porous holes is, for example, 50 or less in an arbitrarily specified rectangular area of ​​10 μm x 10 μm when the second metal layer 13 or the third metal layer 14 is viewed in a plane.

[0066] In the porous shape of the second metal layer 13 and the third metal layer 14, the distance between two adjacent holes (porous holes) is preferably 1.2 μm or more and 3.0 μm. If the distance between two adjacent holes (the center-to-center distance between two holes) exceeds 3.0 μm, the number of porous holes will be reduced to less than five within a 10 μm × 10 μm rectangular area, which may result in an insufficient anchoring effect and in poor adhesion between the second metal layer 13 and the resin frame 20 and between the third metal layer 14 and the resin portion 30. On the other hand, if the distance between two adjacent holes is less than 1.2 μm, the adjacent holes may connect, making it impossible to maintain the porous diameter, and the ratio (b / a) may be less than 1.3, which may result in an insufficient anchoring effect and poor adhesion between the second metal layer 13 and the resin frame 20 and between the third metal layer 14 and the resin portion 30.

[0067] 3, the surface area (porous surface area) of the porous second metal layer 13 is preferably 1.1 times or more that of the smooth first metal layer 12 (i.e., smooth plated metal) without a porous shape. If the porous surface area is less than 1.1 times, the anchoring effect will not be sufficient, and the adhesion between the second metal layer 13 and the resin frame 20 and between the third metal layer 14 and the resin part 30 may be reduced. Note that the upper limit of the porous surface area is not particularly limited as long as the ratio (b / a) is 4.0 or less.

[0068] [Method of Manufacturing Optical Semiconductor Device Package] Next, a method of manufacturing the optical semiconductor device package 2 according to the present embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining the method of manufacturing the optical semiconductor device package 2 according to the embodiment.

[0069] 4A, the lead frame body 11 is fabricated in a predetermined shape. For example, the lead frame body 11 can be fabricated by subjecting a metal substrate made of copper or a copper alloy to press working such as punching or hammering, or by subjecting the metal substrate to a molding technique such as etching. Specifically, a first lead frame body 11a and a second lead frame body 11b are fabricated.

[0070] 4B, a first metal layer 12 is formed to cover the lead frame body 11. Specifically, the first metal layer 12 is formed to cover the entire surface of the first lead frame body 11a, and the first metal layer 12 is formed to cover the entire surface of the second lead frame body 11b. The first metal layer 12 is, for example, a plated film formed by a plating method. The first metal layer 12 may be a single-layer metal layer formed by a single metal film, or may be a metal layer group in which multiple metal films are stacked.

[0071] 4(c), a masking member 40 having a predetermined shape is formed on the surface of the first metal layer 12 that covers the lead frame body 11. The masking member 40 is provided in a portion of the first metal layer 12 other than the areas where the second metal layer 13 and the third metal layer 14 are to be formed. In other words, the areas of the first metal layer 12 where the second metal layer 13 and the third metal layer 14 are to be formed are not covered with the masking member 40, and openings are formed in the masking member 40. Masking rubber or resist can be used as the masking member 40.

[0072] For example, when the masking member 40 is formed using a resist, an electrodeposited resist can be used as the masking member 40. The electrodeposited resist is a resist in which only the light-irradiated portions are removed by exposing and developing the portions irradiated with light. Therefore, by applying the electrodeposited resist to the entire surface of the first metal layer 12, irradiating the electrodeposited resist with light while avoiding the portions where the second metal layer 13 and the third metal layer 14 will be formed, and then performing exposure and development, an electrodeposited mask having openings in the regions where the second metal layer 13 and the third metal layer 14 will be formed can be formed.

[0073] Next, a metal film is formed on the lead frame body 11 covered with the masking member 40, and the masking member 40 is removed, thereby partially forming a second metal layer 13 and a third metal layer 14 on the surface of the first metal layer 12 covering the lead frame body 11, as shown in Fig. 4(d). Specifically, the second metal layer 13 is formed in the region of the first metal layer 12 where the resin frame 20 is to be formed, and the third metal layer 14 is formed on the first metal layer 12 covering the side surface of the lead frame body 11.

[0074] In this embodiment, a porous plating film is formed on the lead frame body 11 covered with the masking member 40, thereby forming the second metal layer 13 and the third metal layer 14, each of which is a porous plating film. Specifically, the second metal layer 13 and the third metal layer 14 are porous nickel plating films formed by a nickel electroplating method. In this case, an additive is blended into the nickel electroplating solution used in the nickel electroplating method. This additive is an organic additive and is preferably blended into the nickel electroplating solution at a ratio of 0.1% to 2% (e.g., 0.5%). By adding the additive to the nickel electroplating solution, the additive is adsorbed onto the surface of the nickel metal during the nickel plating precipitation reaction, creating areas where the nickel plating precipitation reaction is inhibited. On the other hand, nickel plating areas where the additive is not adsorbed are areas where the nickel plating precipitation reaction is not inhibited, and a normal precipitation reaction occurs. Then, the nickel plating precipitation reaction is repeated between areas where the precipitation reaction is inhibited and areas where the precipitation reaction is not inhibited, thereby forming a porous nickel plating film. Specifically, the additive adsorbed in the nickel plating film vaporizes and becomes hollow pores, resulting in a porous nickel plating film.

[0075] As described above, the lead frame 10 is fabricated by forming the second metal layer 13 and the third metal layer 14 on the first metal layer 12 that covers the lead frame body 11 .

[0076] Next, as shown in Figure 4(e), the resin frame 20 is formed. The resin frame 20 can be formed by resin molding so as to surround the optical semiconductor element mounting portion 10b (see Figure 1) of the lead frame 10. At this time, the resin frame 20 is formed so as to cover the porous second metal layer 13. As a result, a portion of the resin frame 20 penetrates into the porous pores of the second metal layer 13, thereby improving the adhesion between the resin frame 20 and the second metal layer 13 by an anchor effect.

[0077] At the same time as forming the resin frame 20, the resin material that constitutes the resin frame 20 is filled into the gap G between the first lead frame body 11a and the second lead frame body 11b to form the resin portion 30. At this time, the resin portion 30 is formed so as to cover the porous third metal layer 14. As a result, a portion of the resin portion 30 enters the porous pores of the third metal layer 14, thereby improving the adhesion between the resin portion 30 and the third metal layer 14 by an anchor effect.

[0078] By going through the above steps, the optical semiconductor device package 2 in which the resin frame 20 is formed on the lead frame 10 is completed.

[0079] As shown in FIG. 1 , the optical semiconductor element 3 is die-bonded to the optical semiconductor element mounting portion 10b of the package 2 for the optical semiconductor device via a die bonding material 5, and the optical semiconductor element 3 and the first metal layer 12 are wire-bonded with wires 6. Thereafter, the internal space of the package 2 for the optical semiconductor device (i.e., the internal space of the resin frame 20) is filled with a liquid sealing resin 4, and the liquid sealing resin 4 is hardened, thereby completing the optical semiconductor device 1.

[0080] The optical semiconductor device 1 configured in this manner is a packaged surface-mounted mounting component, and is used as a light source in various fields such as the lighting field, the automotive field, and the display field.

[0081] As described above, according to the optical semiconductor device 1 and the package 2 for the optical semiconductor device of this embodiment, a second metal layer 13 is partially provided at the location where the first metal layer 12 covering the lead frame main body 11 and the resin frame body 20 are joined.

[0082] With this configuration, the convex second metal layer 13 is formed on the first metal layer 12, thereby increasing the bonding area of ​​the portion where the metal portion formed by the first metal layer 12 and the second metal layer 13 is bonded to the resin frame 20. This improves the adhesion between the metal portion formed by the first metal layer 12 and the second metal layer 13 and the resin frame 20 compared to when the resin frame 20 is formed only on the flat first metal layer 12. Therefore, it is possible to prevent gaps from being generated at the interface between the metal portion formed by the first metal layer 12 and the second metal layer 13 and the resin frame 20 (i.e., the interface between the lead frame 10 and the resin frame 20), thereby preventing foreign matter such as sulfides from entering the resin frame 20.

[0083] In particular, in the optical semiconductor device 1 and the package for an optical semiconductor device 2 according to the present embodiment, the surface of the second metal layer 13 is in contact with the resin frame 20, and the surface roughness of the second metal layer 13 is higher than the surface roughness of the first metal layer 12. This effectively improves the adhesion between the second metal layer 13 and the resin frame 20. As a result, the bonding strength between the lead frame body 11 and the resin frame 20 can be improved.

[0084] Furthermore, by forming the convex second metal layer 13 on the first metal layer 12, it is possible to increase the length along the interface between the resin frame 20 and the metal portion formed by the first metal layer 12 and the second metal layer 13 from the outer surface to the inner surface of the resin frame 20, compared to when the resin frame 20 is formed only on the flat first metal layer 12. This increases the path that foreign matter such as sulfides can take to penetrate into the resin frame 20, further preventing foreign matter such as sulfides from penetrating into the resin frame 20. Therefore, when the first metal layer 12 contains a silver film made of silver, it is possible to prevent sulfides from penetrating into the resin frame 20 and blackening the silver film, thereby preventing the light reflectance of the silver film from decreasing.

[0085] Furthermore, the adhesion between the metal portion formed by the first metal layer 12 and the second metal layer 13 and the resin frame body 20 is improved, and the length along the interface between the metal portion formed by the first metal layer 12 and the second metal layer 13 and the resin frame body 20 is increased, which makes it possible to prevent the solder material from penetrating the interface and entering the resin frame body 20 due to the heat of reflow when soldering the optical semiconductor device 1 to the mounting board.

[0086] As described above, the optical semiconductor device package 2 and the optical semiconductor device 1 according to the present embodiment can prevent foreign matter such as sulfides or solder from entering the resin frame 20. This can prevent problems such as deterioration of the components that make up the optical semiconductor device package 2 and the optical semiconductor device 1. Therefore, a highly reliable optical semiconductor device package 2 and an optical semiconductor device 1 can be obtained.

[0087] Furthermore, by improving the adhesion between the resin frame 20 and the metal portion constituted by the first metal layer 12 and the second metal layer 13, it is possible to prevent the sealing resin 4 from leaking from the interface between the resin frame 20 and the first metal layer 12 when the liquid sealing resin 4 is filled into the resin frame 20. In other words, not only can it be prevented that foreign matter enters the interior of the resin frame 20 from the exterior thereof, but it can also be prevented that the sealing resin 4 inside the resin frame 20 leaks out to the exterior of the resin frame 20.

[0088] Furthermore, in the package 2 for an optical semiconductor device and the optical semiconductor device 1 according to this embodiment, the second metal layer 13 and the third metal layer 14 have a porous shape, and a portion of the resin frame 20 is embedded in the porous hole in the second metal layer 13, and a portion of the resin part 30 is embedded in the porous hole in the third metal layer 14.

[0089] With this configuration, the resin frame 20 and parts of the resin portion 30 are embedded in the porous holes, creating an anchor effect that further improves adhesion between the metal portion formed by the first metal layer 12 and the second metal layer 13 and the resin frame 20. As a result, it is possible to further prevent gaps from occurring at the interface between the resin frame 20 and the first metal layer 12. This makes it possible to further prevent foreign matter from entering the resin frame 20 from the outside, and to further prevent the sealing resin 4 inside the resin frame 20 from leaking out of the resin frame 20.

[0090] In particular, by embedding a portion of the resin frame body 20 and the resin part 30 in the porous holes, it is possible to almost eliminate the gap at the interface between the metal part consisting of the first metal layer 12 and the second metal layer 13 and the resin frame body 20, thereby realizing a highly airtight package 2 for an optical semiconductor device.

[0091] (Modifications) The optical semiconductor device 1 and the package for an optical semiconductor device 2 according to the present disclosure have been described above based on the embodiments and modifications, but the present disclosure is not limited to the above-described embodiments and modifications.

[0092] For example, in the above-described embodiment, the entire surface of the lead frame body 11 is flat, but this is not limited thereto. Specifically, as in the optical semiconductor device 1A and optical semiconductor device package 2A shown in FIG. 5 , a recess 11p may be formed in a portion of the surface of the lead frame body 11A in the lead frame 10A. In this case, the first metal layer 12A has a recess 12p formed along the recess 11p, and the second metal layer 13 is provided in this recess 12p. The recess 11p of the lead frame body 11A can be formed, for example, by press working. As an example, the recess 11p and the recess 12p are V-groove-shaped grooves. Note that FIG. 5A is a plan view of the optical semiconductor device 1A, and FIG. 5B is a cross-sectional view taken along line b-b in FIG. 5A. The area surrounded by the dashed line in FIG. 5A indicates the area where the second metal layer 13 is provided.

[0093] Thus, the provision of the recessed portion 12p in the second metal layer 13 can further increase the bonding area between the resin frame 20 and the metal portion formed by the first metal layer 12A and the second metal layer 13, thereby further improving the adhesion between the resin frame 20 and the metal portion formed by the first metal layer 12A and the second metal layer 13. Furthermore, the provision of the second metal layer 13 in the recessed portion 12p can further increase the length along the interface between the resin frame 20 and the metal portion formed by the first metal layer 12A and the second metal layer 13. This can further prevent foreign matter such as sulfide or solder from entering the resin frame.

[0094] In the above embodiment, the third metal layer 14 provided on the side surface of the lead frame body 11 is provided on each of the first metal layer 12 covering the gap G side surface of the first lead frame body 11a and the first metal layer 12 covering the gap G side surface of the second lead frame body 11b, but this is not limited to this. Specifically, the third metal layer 14 may be provided on the first metal layer 12 covering the gap G side surface of at least one of the first lead frame body 11a and the second lead frame body 11b.

[0095] In addition, in the above embodiment, the second metal layer 13 and the third metal layer 14 are formed simultaneously, but this is not limiting. That is, the second metal layer 13 and the third metal layer 14 do not have to be formed simultaneously. For example, the third metal layer 14 may be formed after the second metal layer 13 is formed, or the second metal layer 13 may be formed after the third metal layer 14 is formed.

[0096] In the above embodiment, the second metal layer 13 and the third metal layer 14 are made of nickel, but this is not limiting. The second metal layer 13 and the third metal layer 14 may be made of a metal material other than nickel as long as they have a porous shape.

[0097] In the above embodiment, the second metal layer 13 and the third metal layer 14 are plated films formed by plating, but this is not limiting. The second metal layer 13 and the third metal layer 14 may be formed by a method other than plating as long as they have a porous shape.

[0098] Furthermore, in the optical semiconductor device 1 according to the above embodiment, an LED chip is mounted as the optical semiconductor element 3 in the optical semiconductor device package 2, but this is not limiting. The optical semiconductor element 3 mounted in the optical semiconductor device package 2 may be, for example, a light-receiving element such as a photodiode, or may be both a light-emitting element and a light-receiving element. In other words, the optical semiconductor device package 2 may be mounted with both a light-emitting element and a light-receiving element.

[0099] In the above embodiment, the optical semiconductor element 3 is a double-sided electrode type LED chip, but this is not limiting. For example, the optical semiconductor element 3 may be a single-sided electrode type LED chip.

[0100] Furthermore, in the above embodiment, the optical semiconductor device package 2 is a package suitable for mounting an optical semiconductor element, but the element mounted in the optical semiconductor device package 2 is not limited to an optical semiconductor element and may be a semiconductor element other than an optical semiconductor element. In other words, the optical semiconductor device package 2 according to the above embodiment is a package that can also be called an "optical semiconductor device package." Furthermore, although the optical semiconductor device package 2 has a rectangular parallelepiped structure as a whole, the shape of the optical semiconductor device package 2 is not limited to a rectangular parallelepiped.

[0101] In addition, the present disclosure also includes embodiments obtained by applying various modifications to the above-described embodiments that would occur to those skilled in the art, and embodiments realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure. The present disclosure also includes any combination of two or more claims from the multiple claims set forth in the claims at the time of filing, provided that there is no technical contradiction. For example, when a dependent claim set forth in the claims at the time of filing is made into a multiple claim or multiple multiple claims that cite all of the superordinate claims within the scope of the technical contradiction, the present disclosure also includes any combination of all claims included in that multiple claim or multiple multiple multiple claim.

[0102] INDUSTRIAL APPLICABILITY The technology of the present disclosure is useful not only as a package for an optical semiconductor device for arranging an optical semiconductor element and an optical semiconductor device, but also as a package for arranging a semiconductor element and a semiconductor device including the package.

[0103] REFERENCE SIGNS LIST 1, 1A Optical semiconductor device 2, 2A Package for optical semiconductor device 3 Optical semiconductor element 4 Sealing resin 5 Die bonding material 6 Wire 10, 10A Lead frame 10a Soldering portion 10b Optical semiconductor element mounting portion 11, 11A Lead frame body 11a First lead frame body 11b Second lead frame body 11p Recess 12, 12A First metal layer 12p Depression portion 13 Second metal layer 14 Third metal layer 20 Resin frame 30 Resin portion 40 Masking member G Gap

Claims

1. A package for an optical semiconductor device for encapsulating an optical semiconductor element with encapsulating resin, comprising: a lead frame body; a first metal layer covering the lead frame body; a resin frame body provided on the first metal layer; and a second metal layer partially provided at a location where the first metal layer and the resin frame body are joined, wherein the surface of the second metal layer contacts the resin frame body, and the surface roughness of the second metal layer is higher than the surface roughness of the first metal layer.

2. The package for an optical semiconductor device according to claim 1, wherein the width of the second metal layer at the location where the first metal layer and the resin frame are joined is 50% or more of the width of the resin frame.

3. The package for an optical semiconductor device according to claim 1, wherein a recess is formed on the surface of the lead frame body, the first metal layer has a recessed portion formed along the recessed portion, and the second metal layer is provided in the recessed portion.

4. The package for an optical semiconductor device according to any one of claims 1 to 3, wherein the second metal layer has a porous shape, and a portion of the resin frame is embedded in the holes of the porous shape.

5. The optical semiconductor device package according to claim 4, wherein the second metal layer is made of nickel having a purity of 99% or more.

6. The package for optical semiconductor devices according to any one of claims 1 to 3, wherein the lead frame body is separated into a first lead frame body and a second lead frame body via a gap, a resin portion made of the same resin material as that constituting the resin frame body is provided in the gap, and a third metal layer is provided on the first metal layer covering the side surface of at least one of the first lead frame body and the second lead frame body on the gap side.

7. The package for an optical semiconductor device according to claim 6, wherein the third metal layer has an area ratio of 50% or more to the first metal layer covering the side surface.

8. The package for an optical semiconductor device according to claim 6, wherein the third metal layer is provided on each of the first metal layer covering the side surface of the first lead frame body facing the gap and the first metal layer covering the side surface of the second lead frame body facing the gap.

9. The package for an optical semiconductor device according to claim 6, wherein the third metal layer has a porous shape, the second metal layer has the same porous shape as the third metal layer, a portion of the resin portion is embedded in the porous hole in the third metal layer, and a portion of the resin frame is embedded in the porous hole in the second metal layer.

10. The optical semiconductor device package according to claim 9, wherein the third metal layer is made of nickel having a purity of 99% or more.

11. The package for an optical semiconductor device according to claim 9, wherein the pore diameter of the porous holes in each of the second metal layer and the third metal layer is 0.05 μm or more and 2.0 μm or less.

12. The package for an optical semiconductor device according to claim 9, wherein the depth of the porous holes in each of the second metal layer and the third metal layer is 0.2 μm or more and 2 μm or less.

13. The package for an optical semiconductor device according to claim 9, wherein the area of ​​the porous holes in each of the second metal layer and the third metal layer increases toward the depth of the holes.

14. The package for an optical semiconductor device according to any one of claims 1 to 3, wherein the first metal layer is a metal layer group in which a plurality of metal films are stacked, and the plurality of metal films includes a first metal film made of silver.

15. The optical semiconductor device package according to claim 14, wherein the plurality of metal films includes a second metal film made of nickel, palladium, gold, or an alloy containing any of these.

16. An optical semiconductor device comprising: the package for an optical semiconductor device according to any one of claims 1 to 3; an optical semiconductor element located on the first metal layer and surrounded by the resin frame; and a sealing resin provided within the resin frame for sealing the optical semiconductor element.

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