WO2023008252A1 - Package and power module - Google Patents

Package and power module Download PDF

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Publication number
WO2023008252A1
WO2023008252A1 PCT/JP2022/028038 JP2022028038W WO2023008252A1 WO 2023008252 A1 WO2023008252 A1 WO 2023008252A1 JP 2022028038 W JP2022028038 W JP 2022028038W WO 2023008252 A1 WO2023008252 A1 WO 2023008252A1
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WO
WIPO (PCT)
Prior art keywords
package
heat sink
layer
sink plate
plating layer
Prior art date
Application number
PCT/JP2022/028038
Other languages
French (fr)
Japanese (ja)
Inventor
芳和 三原
Original Assignee
Ｎｇｋエレクトロデバイス株式会社
日本碍子株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Ｎｇｋエレクトロデバイス株式会社, 日本碍子株式会社 filed Critical Ｎｇｋエレクトロデバイス株式会社
Priority to JP2023538453A priority Critical patent/JPWO2023008252A1/ja
Publication of WO2023008252A1 publication Critical patent/WO2023008252A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/02—Containers; Seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/02—Containers; Seals
    • H01L23/04—Containers; Seals characterised by the shape of the container or parts, e.g. caps, walls
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/07—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L29/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/18—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different subgroups of the same main group of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N

Definitions

  • the present disclosure relates to packages and power modules, and more particularly to a package having a heat sink plate on which electronic components are to be mounted, and a power module having a package, electronic components and a lid.
  • Patent Document 1 discloses a lead terminal used in an electronic component housing package for housing high power electronic components.
  • the lead terminal is made of metal such as Fe (iron)--Ni (nickel)--Co (cobalt) alloy, Fe--Ni alloy, Fe, Cu (copper), or Cu alloy.
  • the lead terminal is made of a material having a core material such as Fe--Ni--Co alloy, Fe--Ni alloy, or Fe, and Cu surrounding it.
  • the thermal stress due to the difference in thermal expansion can be reduced when the lead terminals are fixed using a bonding material such as Ag (silver) solder.
  • a bonding material such as Ag (silver) solder.
  • the skin effect causes the electrical signal to be transmitted only in the portion near the surface of the lead terminal, so Cu is provided only in the portion near the surface of the lead terminal.
  • a high-frequency signal can be efficiently transmitted only by coating the surface of the lead terminal with a thin layer of Cu of about 0.5 to 5 ⁇ m by plating or the like.
  • Patent Document 2 discloses a package having a ceramic frame and lead terminals.
  • a metal plate made of Fe--Ni--Co alloy or Fe--Ni alloy having a coefficient of thermal expansion similar to that of the ceramic of the ceramic frame is used for the lead terminal.
  • a Ni-plated film and an Au (gold)-plated film are formed on the metal portion exposed to the surface for connection with a bonding wire or prevention of oxidation or sulfurization due to contact with the outside air. is disclosed.
  • Patent Document 3 discloses a package having conductive leads.
  • the conductive leads may be formed from solid copper rather than an alloy.
  • the publication alleges that the use of solid copper rather than alloys improves electrical conductivity. Solid copper also offers cost advantages.
  • the system, including the package may be plated using, for example, NiAu (nickel/gold) or NiPdAu (nickel/palladium/gold) at various stages of its manufacture.
  • Patent Document 4 has a frame containing resin, terminal electrodes attached thereto, and a heat sink plate containing Cu with a purity of 95.0 wt% (weight percent) or more. Disclose the package.
  • the material of the terminal electrode may be an Fe—Ni alloy, but is preferably a material containing Cu with a purity of 90 wt % or more.
  • Nickel plating and gold plating on the nickel plating may be applied to the surface of the terminal electrode for the purpose of ensuring bondability with a bonding wire or the like.
  • Patent Document 2 discloses a configuration in which Ni plating and Au plating are provided on a lead terminal made of a magnetic material.
  • the thickness of the Au plating using an expensive material be the minimum necessary.
  • the thinner the Au plating the closer the Ni plating, which is a magnetic material, to the surface.
  • Magnetic bodies are more affected by the skin effect than non-magnetic bodies. According to the study of the present inventors, when a very high frequency is used, the high frequency loss due to the skin effect of the lead terminal (lead frame) provided on the package can become a significant problem.
  • Patent Document 4 discloses that a terminal electrode made of a non-magnetic material containing Cu as a main component is sequentially plated with Ni and Au.
  • the thickness of the Au plating using an expensive material be the minimum necessary.
  • the thinner the Au plating the closer the Ni plating, which is a magnetic material, to the surface.
  • Magnetic bodies are more affected by the skin effect than non-magnetic bodies. According to studies by the present inventors, when very high frequencies are used, high-frequency loss due to the skin effect of the terminal electrodes (lead frames) provided on the package can become a significant problem.
  • the present disclosure has been made to solve the above problems, and its purpose is to provide a package and a power module that can simultaneously suppress manufacturing costs and high-frequency loss.
  • a first aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer.
  • the heat sink plate has a mounting surface on which electronic components are to be mounted.
  • the frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate.
  • the lead frame is attached to the frame and is made of a magnetic material.
  • the plating layer covers at least part of the lead frame.
  • the plating layer includes a first layer having a first thickness and a second layer having a second thickness.
  • the first layer directly covers the at least part of the lead frame, is made of a non-magnetic material, and is made of a metal other than gold and palladium.
  • the second layer directly covers the first layer and is made of at least one of gold, palladium and silver. The sum of the first thickness and the second thickness is 1 ⁇ m or more, and the second thickness is less than 1 ⁇ m.
  • a second aspect is the package according to the first aspect, wherein the metal includes at least one of copper and silver.
  • a third aspect is the package according to the first or second aspect, wherein the first thickness is 0.5 ⁇ m or more.
  • a fourth aspect is the package according to any one of the first to third aspects, wherein the plating layer covers the mounting surface of the heat sink plate.
  • a fifth aspect is the package according to the fourth aspect, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
  • a sixth aspect is the package according to the fourth aspect, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer. It is
  • a seventh aspect is the package according to any one of the first to sixth aspects, the electronic component mounted on the mounting surface of the heat sink plate, and the electronic component attached to the package so as to seal the electronic component. and a power module having a lid.
  • the electronic component has an operating frequency of 3.6 GHz or higher.
  • An eighth aspect is the power module according to the seventh aspect, wherein the second layer of the package has atomic diffusion of the metal from the first layer.
  • a ninth aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer.
  • the heat sink plate has a mounting surface on which electronic components are to be mounted.
  • the frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate.
  • the lead frame is attached to the frame and is made of a non-magnetic material.
  • the plating layer directly covers at least part of the lead frame, is made of at least one of gold, palladium and silver, and has a thickness of less than 1 ⁇ m.
  • a tenth aspect is the package according to the ninth aspect, wherein the lead frame is made of copper or a copper alloy.
  • An eleventh aspect is the package according to the ninth or tenth aspect, wherein the plating layer covers the mounting surface of the heat sink plate.
  • a twelfth aspect is the package according to the eleventh aspect, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
  • a thirteenth aspect is the package according to the eleventh aspect, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer. It is
  • a fourteenth aspect is the package according to any one of the ninth to thirteenth aspects, the electronic component mounted on the mounting surface of the heat sink plate, and the electronic component attached to the package so as to seal the electronic component. and a power module having a lid.
  • the electronic component has an operating frequency of 3.6 GHz or higher.
  • a fifteenth aspect is the power module according to the fourteenth aspect, wherein the plating layer of the package has copper atom diffusion from the lead frame.
  • a sixteenth aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer.
  • the heat sink plate has a mounting surface on which electronic components are to be mounted.
  • the frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate.
  • the lead frame is attached to the frame and is made of a magnetic material.
  • the plating layer directly covers at least a portion of the lead frame, is made of silver, has a thickness of 1 ⁇ m or more, and has an exposed surface.
  • the second thickness which is the thickness of the second layer made of at least one of gold, palladium and silver, which are expensive materials, is less than 1 ⁇ m.
  • the manufacturing cost of the package can be suppressed.
  • the first layer and the second layer directly covering it form a non-magnetic film with a thickness of 1 ⁇ m or more on the surface of the lead frame. This suppresses the electrical loss of the high-frequency current flowing through the lead frame due to the skin effect. As described above, the manufacturing cost of the package and the high frequency loss can be suppressed at the same time.
  • the thickness of the plated layer made of at least one of gold, palladium, and silver, which are expensive materials is less than 1 ⁇ m. Thereby, the manufacturing cost of the package can be suppressed.
  • a nonmagnetic conductor region having a sufficient thickness is secured along the surface of the leadframe by the plating layer and the portion of the leadframe made of a nonmagnetic material covered by the plating layer. This suppresses the electrical loss of the high-frequency current flowing through the lead frame due to the skin effect. As described above, the manufacturing cost of the package and the high frequency loss can be suppressed at the same time.
  • FIG. 2 is a top view schematically showing the configuration of the power module according to Embodiment 1;
  • FIG. 2 is a schematic cross-sectional view along line II-II of FIG. 1;
  • FIG. 2 is a top view schematically showing the configuration of the package in Embodiment 1;
  • FIG. Figure 4 is a schematic cross-sectional view along line IV-IV of Figure 3; 5 is an enlarged view of region V of FIG. 4;
  • FIG. FIG. 4 is a graphical representation schematically showing the relationship between frequency and skin depth in the skin effect for various materials;
  • FIG. 10 is a cross-sectional view schematically showing the configuration of a package in Embodiment 2;
  • FIG. 11 is a cross-sectional view schematically showing the configuration of a power module according to Embodiment 3;
  • FIG. 11 is a cross-sectional view schematically showing the configuration of a package in Embodiment 3;
  • FIG. 10 is an enlarged view of region X in FIG. 9;
  • FIG. 12 is a cross-sectional view schematically showing the structure of a package in Embodiment 4;
  • FIG. 14 is a cross-sectional view schematically showing the configuration of a package in Embodiment 5;
  • FIG. 20 is a cross-sectional view schematically showing the configuration of a package in Embodiment 6;
  • FIG. 1 is a top view schematically showing the configuration of power module 901 according to Embodiment 1.
  • FIG. FIG. 2 is a schematic cross-sectional view along line II-II of FIG.
  • the power module 901 includes a package 101 having a cavity CV, a power semiconductor element 200 (electronic component) mounted on the package 101 within the cavity CV, and attached to the package 101 so as to seal the power semiconductor element 200. It has a lid 300 .
  • the power module 901 also has an adhesive layer 46, a bonding layer 42, and bonding wires 205 (wiring members).
  • the power semiconductor element 200 is a high frequency semiconductor element, and therefore the power module 901 is a high frequency module.
  • the power semiconductor device 200 may have an operating frequency of 3.6 GHz or higher. In order to use a high operating frequency of about 3.6 GHz or higher, it is preferable that the power semiconductor device 200 uses a wide bandgap semiconductor.
  • the power semiconductor device 200 is a GaN (gallium nitride) transistor. Note that the operating frequency of the power semiconductor device 200 may be 6.0 GHz or less.
  • the package 101 includes a heat sink plate 50 having a mounting surface RM facing the cavity CV.
  • Power semiconductor element 200 is mounted on mounting surface RM.
  • Mounting surface RM and power semiconductor element 200 are preferably bonded to each other via bonding layer 42 containing thermosetting resin and metal.
  • the thermosetting resin of the bonding layer 42 preferably contains an epoxy resin.
  • the metal of the bonding layer 42 preferably contains silver.
  • the bonding layer 42 may be composed only of metal without containing a thermosetting resin.
  • other electronic components (not shown) may be arranged on mounting surface RM.
  • the adhesive layer 46 bonds the package 101 and the lid 300 together. Thereby, the power semiconductor element 200 is sealed within the cavity CV. Therefore, the power semiconductor element 200 is highly airtight and protected from the external environment so that water vapor and other gases in the atmosphere do not enter.
  • the bonding wires 205 connect the power semiconductor element 200 and the lead frame 91 (electrode terminals) of the package 101 to each other.
  • power semiconductor element 200 and lead frame 91 are electrically connected to each other.
  • the electrical connection between power semiconductor element 200 and lead frame 91 may be secured by a wiring member other than bonding wire 205, in which case bonding wire 205 is not necessarily required.
  • FIG. 3 is a top view schematically showing the configuration of the package 101 according to Embodiment 1.
  • FIG. FIG. 4 is a schematic cross-sectional view along line IV-IV of FIG.
  • FIG. 5 is an enlarged view of area V in FIG.
  • Package 101 is a component that will be used for the manufacture of power module 901 (FIGS. 1 and 2).
  • the package 101 forms a sealed cavity CV by attaching the lid 300 (FIG. 2).
  • the package 101 has a heat sink plate 50 , a frame 81 , a lead frame 91 and a plating layer 20 .
  • package 101 further includes resin adhesive layer 61 , heat sink adhesive layer 41 , additional adhesive layer 62 , and additional frame 82 .
  • the heat sink plate 50 has a mounting surface RM on which the power semiconductor element 200 is mounted. In FIGS. 3 and 4, power semiconductor element 200 is not yet mounted on mounting surface RM, and thus mounting surface RM is exposed.
  • the frame 81 is attached to the heatsink plate 50 and surrounds the mounting surface RM of the heatsink plate 50 in plan view (field of view in the XY plane).
  • the heat sink plate 50 is made of a metallic material, which can be either composite or non-composite.
  • the composite material may be a laminated film configured by laminating different material films in the thickness direction (longitudinal direction in FIG. 4). These different material films are typically a Cu film and a Mo (molybdenum) film.
  • the non-composite material preferably contains copper with a purity of 95.0 wt % or higher, more preferably a non-composite material containing copper with a purity of 99.8 wt % or higher.
  • the copper content of the heat sink plate 50 is preferably less than 100 wt%.
  • the lead frame 91 is attached to the frame 81 with the resin adhesive layer 61 .
  • the lead frame 91 has a protruding portion that protrudes outward from the outer edge of the frame 81 and a root portion inside the protruding portion in a plan view (XY plane). The root portion is adhered to the frame body 81 via the resin adhesive layer 61 .
  • the lead frame 91 is made of a magnetic material, such as an Fe--Ni alloy (an alloy containing Fe and Ni) or an Fe--Ni--Co alloy (an alloy containing Fe, Ni and Co). Note that the lead frame 91 may be provided with a magnetic plated film (for example, a Ni plated film), and this magnetic plated film is regarded as part of the lead frame 91 made of a magnetic material.
  • the plating layer 20 covers at least part of the lead frame 91 . At least the protruding portion of the lead frame 91 is preferably covered with the plating layer 20 .
  • the plating layer 20 may cover the entire leadframe 91 as shown in FIG.
  • the plating layer 20 (Fig. 5) includes a first layer 21 having a first thickness and a second layer 22 having a second thickness.
  • the first layer 21 directly covers at least part (all in this embodiment) of the lead frame 91 .
  • the first layer 21 is made of a non-magnetic material, and is made of a metal different from both Au and Pd. This metal forming the first layer 21 contains at least one of Cu and Ag, preferably Cu.
  • a material different from the material of the second layer 22 is selected as the material of the first layer 21 so that the material cost can be reduced.
  • the second layer 22 directly covers the first layer 21 and is made of at least one of Au, Pd and Ag.
  • the second layer 22 By providing such a second layer 22, it is possible to prevent the surface of the first layer 21 from being deteriorated due to oxidation, sulfurization, or the like. If suppression of not only oxidation but also sulfurization is important, the second layer 22 preferably consists of at least one of Au and Pd. On the other hand, from the point of view of the material cost of the second layer 22, the second layer 22 preferably consists at least partially of Ag, more preferably entirely of Ag.
  • the second layer 22 may have atomic diffusions of the metal (eg Cu) from the first layer 21 .
  • the first layer 21 may also have atomic diffusion from the second layer 22 .
  • the sum of the first thickness and the second thickness in other words, the thickness of the plating layer 20 is 1 ⁇ m or more.
  • the second thickness is less than 1 ⁇ m.
  • the first thickness is preferably 0.5 ⁇ m or more.
  • the second thickness is preferably 0.01 ⁇ m or more. If the second thickness is at this level, it is possible to prevent the surface of the plating layer 20 from being oxidized and impairing the wire bonding properties and the wettability of the bonding layer 42 .
  • the second layer 22 may be a laminated film. Specifically, the second layer 22 may be composed of a Pd film directly covering the first layer 21 and an Au film directly covering the Pd film.
  • the plating layer 20 may cover not only the lead frame 91 but also at least a portion of the heat sink plate 50, especially the mounting surface RM. Furthermore, as shown in FIG. 4 , the heat sink plate 50 has a bottom surface opposite to the mounting surface RM, and the bottom surface may be covered with the plating layer 20 .
  • the surface of the heat sink plate 50 consists of a portion facing the frame (frame 81 in this embodiment) and other portions (hereinafter also referred to as "exposed surface").
  • the plating layer 20 may cover the entire heat sink plate 50 as shown in FIG.
  • the heat sink plate 50 may be provided with a plating layer different from the plating layer 20 .
  • the frame 81 preferably contains resin (first resin).
  • the resin is preferably a thermoplastic resin, such as a liquid crystal polymer.
  • An inorganic filler (first inorganic filler) is preferably dispersed in this resin.
  • This inorganic filler preferably contains at least one of fibrous particles and plate-like particles. The fibrous or plate-like shape prevents the filler from obstructing the flow of the resin when the frame 81 is formed by an injection molding technique or the like.
  • Materials for such inorganic fillers include, for example, silica glass fiber, alumina fiber, carbon fiber, talc ( 3MgO.4SiO.sub.2.H.sub.2O ), wollastonite, mica, graphite, calcium carbonate, dolomite, glass flakes, Glass beads, barium sulfate, and titanium oxide are used.
  • the size of the inorganic filler made of talc on a flat plate is, for example, a particle size of 1 ⁇ m to 50 ⁇ m.
  • the particle size is the arithmetic mean value of the major diameter obtained by cross-sectional observation of the resin.
  • the content of inorganic filler is preferably 30 wt % to 70 wt %.
  • the thermal expansion coefficient of the heat sink plate 50 is that of copper or close to it
  • the thermal expansion coefficient of the inorganic filler is preferably 17 ppm/K or less in view of the thermal expansion coefficient of copper.
  • the material of the frame body 81 preferably has heat resistance to heat treatment at 260° C. for 2 hours.
  • the resin adhesive layer 61 is made of a material different from that of the frame 81 .
  • the resin adhesive layer 61 contains a resin (second resin) different from the resin (first resin) of the frame 81 .
  • the resin of the resin adhesive layer 61 is preferably a thermosetting resin, such as an epoxy resin.
  • An inorganic filler may be dispersed in the resin of the resin adhesive layer 61 .
  • the additional frame 82 is attached via the additional adhesive layer 62 on the frame 81 to which the lead frame 91 is attached by the resin adhesive layer 61 .
  • a lead frame 91 passes between the frame 81 and the additional frame 82 .
  • the additional frame 82 preferably contains resin.
  • the material of the additional frame 82 may be the same as the material of the frame 81 .
  • the material of the additional adhesive layer 62 may be the same as that of the resin adhesive layer 61 .
  • the heat sink adhesive layer 41 adheres the frame 81 and the heat sink plate 50 to each other.
  • the heat sink adhesive layer 41 ensures airtightness between the heat sink plate 50 and the frame 81 .
  • each of the heat sink adhesive layer 41, resin adhesive layer 61, and additional adhesive layer 62 preferably has heat resistance to heat treatment at 260°C for two hours. If it has heat resistance to heat treatment at 260° C. for 2 hours, it is typical in the mounting process of the power semiconductor element 200 (FIG. 2) using a paste adhesive containing a thermosetting resin and a metal. The heat resistance to general heat treatment is ensured.
  • the frame 81 is supported by the heat sink plate 50 via the heat sink adhesive layer 41 .
  • the frame 81 has, for example, a thickness of about 0.3 mm (dimension in the vertical direction in FIG. 4) and an overall width of about 2 mm (dimension in the horizontal direction in FIG. 4).
  • the thickness and overall width of the additional frame 82 may also be the same.
  • Full width refers to the width of one side that constitutes the frame.
  • the heat sink adhesive layer 41 adheres the frame 81 and the heat sink plate 50 to each other.
  • the material of the heat sink adhesive layer 41 is different from the material of the frame 81 .
  • the material of the heat sink adhesive layer 41 may be the same as the material of the resin adhesive layer 61 .
  • the resin of the heat sink adhesive layer 41 is preferably a thermosetting resin, such as an epoxy resin.
  • An inorganic filler is preferably dispersed in the resin of the heat sink adhesive layer 41 .
  • This inorganic filler preferably contains at least one of silica glass and silica, and more preferably consists of silica glass.
  • silica is synonymous with crystalline silica.
  • the thermal expansion coefficient of silica glass is about 0.5 ppm/K, and the thermal expansion coefficient of crystalline silica is about 15 ppm/K. can do. This is especially desired when epoxy resin or fluororesin is used as the resin of the heat sink adhesive layer 41 .
  • the content of the inorganic filler is preferably 50 wt % to 90 wt %.
  • At least one of alumina, aluminum hydroxide, talc, iron oxide, wollastonite, calcium carbonate, mica, titanium oxide, and carbon fiber may be used instead of or together with at least one of silica glass and silica. good.
  • the shape of the inorganic filler is, for example, spherical, fibrous, or plate-like.
  • the frame body 81 has rubber elasticity, so the limitation of the thermal expansion coefficient of the inorganic filler can be almost ignored.
  • the content of the inorganic filler may be adjusted from the viewpoint of fluidity control of the heat sink adhesive layer 41, and is preferably 1 wt % to 10 wt %. From the viewpoint of securing fluidity of the heat sink adhesive layer 41 before curing, spherical silica glass (amorphous silica) having a particle size of 1 ⁇ m to 50 ⁇ m is optimal.
  • FIG. 6 is a graph diagram schematically showing the relationship between the frequency f for various materials and the skin depth t in the skin effect.
  • “Fe--Ni” is specifically 42 alloy.
  • the skin depth t of magnetic materials such as Ni and Fe—Ni is significantly smaller than the skin depth t of non-magnetic materials such as Au, Cu and Pd.
  • non-magnetic materials such as Au, Cu and Pd.
  • magnetic bodies are more affected by the skin effect than non-magnetic bodies.
  • a metal having a magnetic permeability of about 1 ⁇ 10 ⁇ 4 to 1 ⁇ 10 ⁇ 1 [H/m] can be used. or can be used.
  • a metal having a magnetic permeability of about 1 ⁇ 10 ⁇ 6 to 1 ⁇ 10 ⁇ 5 [H/m] can be used.
  • Table 2 below shows the physical property values (resistivity and magnetic permeability) used to calculate the skin depth t shown in FIG. 6 and Table 1.
  • the skin depth t is not extremely small as shown in Table 1 above, so high frequency loss is reduced. It is thought that there are many cases in which it is possible to keep it within the permissible range.
  • a method for manufacturing the power module 901 (Fig. 2) will be described.
  • First a package 101 (FIG. 4) is prepared.
  • the power semiconductor element 200 (FIG. 2) is mounted on the mounting surface RM (FIG. 4) of the heat sink plate 50.
  • the mounting surface RM of the heat sink plate 50 and the power semiconductor element 200 should be bonded to each other via the bonding layer 42 (FIG. 2) containing thermosetting resin and metal.
  • the bonding layer 42 (FIG. 2) containing thermosetting resin and metal. is preferred.
  • the thermosetting resin of the bonding layer 42 preferably contains an epoxy resin.
  • the metal of the bonding layer 42 preferably contains silver.
  • the power semiconductor element 200 and the lead frame 91 are connected by bonding wires 205 (FIG. 2). This ensures electrical connection between power semiconductor element 200 and lead frame 91 .
  • the lid 300 is attached to the package 101 so that the package 101 in which the power semiconductor element 200 is mounted is not thermally damaged enough to cause leakage.
  • the lid 300 is attached to the package 101 so that the heat sink adhesive layer 41, the resin adhesive layer 61, and the additional adhesive layer 62 are not thermally damaged enough to cause leakage.
  • the lid 300 is attached to the package 101 via the adhesive layer 46 cured at a low curing temperature that does not lead to the thermal damage described above. This curing temperature is, for example, less than 260°C.
  • the second thickness which is the thickness of the second layer 22 made of at least one of Au, Pd and Ag, which are expensive materials, is less than 1 ⁇ m.
  • the manufacturing cost of the package 101 can be suppressed.
  • the first layer 21 and the second layer 22 directly covering it form a non-magnetic film having a thickness of 1 ⁇ m or more on the surface of the lead frame 91 . This suppresses the electrical loss of the high-frequency current flowing through the lead frame 91 due to the skin effect.
  • the manufacturing cost of the package 101 and the high frequency loss can be suppressed at the same time.
  • the first thickness is 0.5 ⁇ m or more
  • the plating layer 20 covers the mounting surface RM of the heat sink plate 50, the electric loss due to the skin effect of the high-frequency current flowing through the mounting surface RM is suppressed. Thereby, the high frequency loss can be further suppressed. If the bottom surface of the heat sink plate 50 is also covered with the plating layer 20, electrical loss due to the skin effect can be further suppressed. Moreover, when the entire exposed surface of the heat sink plate 50 is covered with the plating layer 20, electrical loss due to the skin effect can be further suppressed.
  • the plated layer 20 on the surface of the heat sink plate 50 not only suppresses the electrical loss caused by the skin effect as described above, but also has the effect of lowering the electrical resistance itself on the surface of the heat sink plate 50 in some cases. be.
  • the material of the plated layer 20 has a lower electrical resistance than Ni, so such an effect can be obtained.
  • the operating efficiency of power module 901 FOG. 2
  • the electrical resistance of the current path passing through the heat sink plate 50 is low, variations in the electrical resistance among mass-produced packages 101 are less likely to become a problem.
  • the power module 901 is a power amplifier, it is possible to suppress variations in power amplifier output between products.
  • the surface of the plating layer using Ni has low smoothness.
  • the plating layer 20 does not use Ni, the surface of the plating layer 20 can be easily made smooth. The smoother the surface, the shorter the path for current flow across the surface. This results in a lower electrical resistance, thus mitigating the adverse effects of the skin effect.
  • the second layer 22 may have metal atomic diffusion from the first layer 21 .
  • the second layer 22 may have Cu atomic diffusion from the Cu layer as the first layer 21 . This improves the adhesion strength between the first layer 21 and the second layer.
  • the surface of the second layer 22 is likely to be oxidized, which may impede the wire bondability and the wettability of the bonding layer 42.
  • the heat treatment temperature required for mounting the power semiconductor element 200 on the package 101 is as low as possible.
  • the implementation method specifically described above is suitable for this purpose.
  • FIG. 7 is a cross-sectional view schematically showing the structure of package 102 according to the second embodiment.
  • package 102 has frame 80 instead of frame 81 and additional frame 82 (FIG. 4).
  • the material of frame 80 may be the same as that of frame 81 .
  • the lead frame 91 is attached directly to the frame 80 without using the resin adhesive layer 61 and the additional adhesive layer 62 (FIG. 4).
  • the lead frame 91 and the frame 80 are integrally molded by an injection molding method or the like.
  • Package 102 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
  • FIG. 8 is a cross-sectional view schematically showing the configuration of power module 903 according to the third embodiment.
  • Power module 903 corresponds to a structure in which package 101 in power module 901 (FIG. 2: Embodiment 1) is replaced with package 103 .
  • FIG. 9 is a cross-sectional view schematically showing the structure of the package 103 according to the third embodiment.
  • the package 103 has a heat sink plate 50 , a frame 83 , a lead frame 91 and a plating layer 20 .
  • the package 103 further has a bonding layer 40 .
  • Frame 83 is attached to each of lead frame 91 and heat sink plate 50 by bonding layer 40 .
  • the frame body 83 surrounds the mounting surface RM of the heat sink plate 50 in plan view (field of view in the XY plane).
  • the plating layer 20 covers at least part of the lead frame 91 .
  • the plating layer 20 may cover only a portion of the leadframe 91 as shown in FIG.
  • at least portions of the lead frame 91 that protrude outward from the frame 83 in plan view (XY plane) are covered with the plating layer 20 .
  • the surface of lead frame 91 has a portion covered with plating layer 20 and a portion not covered with plating layer 20 but joined to bonding layer 40 .
  • the plating layer 20 may cover not only the lead frame 91 but also a portion of the heat sink plate 50, especially the mounting surface RM. In this case, the plating of the lead frame 91 and the plating of the heat sink plate 50 can be performed simultaneously.
  • FIG. 10 is an enlarged view of region X in FIG. Plated layer 20 includes a first layer 21 and a second layer 22 .
  • the first layer 21 directly covers at least part (only part in this embodiment) of the lead frame 91 .
  • the material and thickness of the first layer 21 and the second layer 22 are the same as those described in the first embodiment.
  • the frame 83 has an insulating frame 31 , a metallized film 32 and a plating film 33 .
  • the insulating frame 31 is made of ceramics.
  • a metallized film 32 is formed on the upper and lower surfaces of the insulating frame 31 .
  • the plated film 33 is formed on the metallized film 32 .
  • One metallized film 32 is bonded to the heat sink plate 50 by the bonding layer 40 via the plating film 33, and the other metallized film 32 is bonded to the lead frame 91 by the bonding layer 40 via the plating film 33.
  • the plated film 33 is, for example, a Ni plated film.
  • the bonding layer 40 is, for example, brazing material.
  • the heat sink plate 50, the frame 83, and the lead frame 91 are prepared.
  • the heat sink plate 50 can be formed, for example, by cutting or punching a metal plate. These members are then bonded together by a bonding layer 40 .
  • the plated layer 20 the first layer 21 and the second layer 22 are formed in order. A package 103 is thus obtained.
  • FIG. 11 is a cross-sectional view schematically showing the configuration of package 104 according to the fourth embodiment.
  • Package 104 has lead frame 94 and plating layer 24 in place of lead frame 91 and plating layer 20 in package 101 (FIG. 4: Embodiment 1), respectively.
  • the respective arrangements of lead frame 94 and plating layer 24 are similar to lead frame 91 and plating layer 20 . Therefore, the plating layer 24 directly covers at least a portion (entirely in this embodiment) of the lead frame 94 .
  • the plating layer 24 may cover not only the lead frame 94 but also at least a portion of the heat sink plate 50, especially the mounting surface RM. Furthermore, as shown in FIG.
  • the heat sink plate 50 has a bottom surface opposite to the mounting surface RM, and the bottom surface may be covered with the plating layer 24 .
  • the surface of the heat sink plate 50 consists of a portion facing the frame (frame 81 in this embodiment) and other portions (hereinafter also referred to as "exposed surface").
  • the entire surface of the heatsink plate 50 except for the portion covered with the heatsink adhesive layer 41 corresponds to the exposed surface.
  • the entire exposed surface may be covered with the plating layer 24 .
  • the plating layer 24 may cover the entire heat sink plate 50 as shown in FIG.
  • the lead frame 94 is made of non-magnetic material.
  • This magnetic body preferably contains copper, for example Cu or a Cu alloy.
  • the Cu alloy preferably contains 90 wt% or more of copper.
  • the plating layer 24 is made of at least one of Au, Pd and Ag. As a result, deterioration due to oxidation, sulfurization, or the like can be suppressed. If suppression of sulfidation as well as oxidation is important, the plating layer 24 is preferably made of at least one of Au and Pd. On the other hand, in terms of material cost, the plating layer 24 preferably consists of Ag at least partially, and more preferably consists entirely of Ag.
  • the plating layer 24 may have Cu atomic diffusion from the leadframe 94 . Leadframe 94 may also have atomic diffusion from plating layer 24 .
  • the plating layer 24 may be a laminated film.
  • the plating layer 24 may be composed of a Pd film as a base layer and an Au film directly covering the Pd film.
  • the thickness of the plating layer 24 is less than 1 ⁇ m.
  • the thickness of the plating layer 24 is preferably 0.01 ⁇ m or more. If the thickness of the plating layer 24 is about this level, it is possible to prevent the surface of the plating layer 24 from being oxidized and impairing the wire bonding properties and the wettability of the bonding layer 42 .
  • Package 104 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
  • the thickness of the plating layer 24 made of at least one of Au, Pd and Ag, which are expensive materials is less than 1 ⁇ m. Thereby, the manufacturing cost of the package 104 can be suppressed.
  • the plating layer 24 and the portion of the lead frame 94 made of a non-magnetic material covered with the plating layer 24 form a non-magnetic conductor region having a sufficient thickness along the surface of the lead frame 94 . Secured. This suppresses the electrical loss of the high-frequency current flowing through the lead frame 94 due to the skin effect. As described above, the manufacturing cost of the package 104 and the high frequency loss can be suppressed at the same time.
  • the plating layer 24 covers the mounting surface RM of the heat sink plate 50, electrical loss due to the skin effect of the high-frequency current flowing through the mounting surface RM is suppressed. Thereby, the high frequency loss can be further suppressed. If the bottom surface of the heat sink plate 50 is also covered with the plating layer 24, electrical loss due to the skin effect can be further suppressed. Moreover, when the entire exposed surface of the heat sink plate 50 is covered with the plating layer 24, electrical loss due to the skin effect can be further suppressed.
  • the plated layer 24 on the surface of the heat sink plate 50 not only suppresses electrical loss caused by the skin effect as described above, but also has the effect of lowering the electrical resistance itself on the surface of the heat sink plate 50 in some cases. be.
  • the material of the plated layer 24 has lower electrical resistance than Ni, so such an effect can be obtained.
  • the electrical resistance of the current path through the heat sink plate 50 the operating efficiency of the power module can be increased.
  • the electrical resistance of the current path passing through the heat sink plate 50 is low, variations in the electrical resistance among mass-produced packages 104 are less likely to become a problem.
  • the power module is a power amplifier, it is possible to suppress variations in power amplifier output between products.
  • the surface of the plating layer using Ni has low smoothness.
  • the plating layer 20 does not use Ni, the surface of the plating layer 20 can be easily made smooth. The smoother the surface, the shorter the path for current flow across the surface. This results in a lower electrical resistance, thus mitigating the adverse effects of the skin effect.
  • the plating layer 24 may have Cu atoms diffused from the lead frame 94 . This improves the adhesion strength between the plating layer 24 and the lead frame 94 .
  • the surface of the plating layer 24 is likely to be oxidized, which may hinder the wire bonding properties and the wettability of the bonding layer 42.
  • the heat treatment temperature required for mounting the power semiconductor element 200 on the package 104 is as low as possible.
  • the mounting method specifically described in Embodiment 1 is suitable for this purpose.
  • FIG. 12 is a cross-sectional view schematically showing the structure of package 105 according to the fifth embodiment.
  • package 105 has frame 80 instead of frame 81 and additional frame 82 (FIG. 4).
  • the material of frame 80 may be the same as that of frame 81 .
  • the lead frame 94 is attached directly to the frame 80 without using the resin adhesive layer 61 and the additional adhesive layer 62 (FIG. 11).
  • the lead frame 94 and the frame 80 are integrally molded by an injection molding method or the like.
  • Package 105 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
  • FIG. 13 is a cross-sectional view schematically showing the configuration of package 106 according to the sixth embodiment.
  • Package 106 corresponds to a structure in which lead frame 91 and plating layer 20 in package 103 (FIG. 9: Embodiment 3) are replaced with lead frame 94 and plating layer 24, respectively. Since the configuration of the sixth embodiment other than the above is substantially the same as the configuration of the above-described third or fourth embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated.
  • Package 106 may be used instead of package 103 in power module 903 (FIG. 8: Embodiment 3).
  • a plating layer made of Ag (hereinafter also referred to as "Ag plating layer") is used.
  • the Ag plating layer directly covers at least a portion of lead frame 91, like first layer 21 (embodiments 1 to 3).
  • the Ag plating layer has an exposed surface, like the second layer 22 (Embodiments 1 to 3).
  • the thickness of the Ag plating layer is 1 ⁇ m or more, like the total thickness of the first layer 21 and the second layer 22 .
  • the seventh embodiment corresponds to the case where both the first layer 21 and the second layer 22 are made of Ag in the first to third embodiments.
  • the seventh embodiment unlike the first to third embodiments, although there is a disadvantage that the materials of the first layer 21 and the second layer 22 cannot be individually optimized, the configuration of the plating layer is simplified. be able to.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Abstract

In the present invention, a heat sink plate (50) has a mounting surface (RM) on which an electronic component (200) is to be mounted. A frame body (81) is attached to the heat sink plate (50), and encloses the mounting surface (RM) of the heat sink plate (50). A lead frame (91) is attached to the frame body (81) and is formed from a magnetic body. A plating layer (20) covers at least a part of the lead frame (91). The plating layer (20) includes a first layer having a first thickness, and a second layer having a second thickness. The first layer directly covers at least a part of the lead frame (91), is formed from a non-magnetic body, and comprises a metal which is neither gold nor palladium. The second layer directly covers the first layer and comprises at least any one of gold, palladium, and silver. The total thickness of the first thickness and the second thickness is at least 1 μm, and the second thickness is less than 1 μm.

Description

パッケージおよびパワーモジュールPackage and power module
　本開示は、パッケージおよびパワーモジュールに関し、特に、電子部品が実装されることになるヒートシンク板を有するパッケージと、パッケージと電子部品と蓋体とを有するパワーモジュールと、に関するものである。 The present disclosure relates to packages and power modules, and more particularly to a package having a heat sink plate on which electronic components are to be mounted, and a power module having a package, electronic components and a lid.
　特開２００６－１２８５８８号公報（特許文献１）は、大電力用の電子部品を収納するための電子部品収納用パッケージに用いられるリード端子を開示している。上記公報が主張するところによれば、リード端子は、Ｆｅ（鉄）－Ｎｉ（ニッケル）－Ｃｏ（コバルト）合金、Ｆｅ－Ｎｉ合金、Ｆｅ、Ｃｕ（銅）、またはＣｕ合金などの金属からなり、好ましくは、ＣｕまたはＣｕ合金のような、Ｃｕ成分を含む金属からなる。さらに好ましくは、リード端子は、Ｆｅ－Ｎｉ－Ｃｏ合金、Ｆｅ－Ｎｉ合金、またはＦｅなどの芯材と、その周りを覆うＣｕとを有する材料からなり、この構成により、リード端子において高周波信号を効率よく伝送させることができるとともに、Ａｇ（銀）ろう等の接合材を用いてリード端子を固定させる際に、熱膨張差による熱応力を小さいものとすることができる。リード端子を伝送する電気信号が高周波信号である場合、表皮効果により電気信号がリード端子の表面に近い部分だけを伝送するようになるので、Ｃｕはリード端子の表面に近い部分だけに設けられていればよく、めっき法などによってリード端子の表面に０．５～５μｍ程度に薄くＣｕを被着させただけでも、高周波信号を効率よく伝送させることが可能となる。 Japanese Patent Application Laid-Open No. 2006-128588 (Patent Document 1) discloses a lead terminal used in an electronic component housing package for housing high power electronic components. According to the above publication, the lead terminal is made of metal such as Fe (iron)--Ni (nickel)--Co (cobalt) alloy, Fe--Ni alloy, Fe, Cu (copper), or Cu alloy. , preferably of a metal containing a Cu component, such as Cu or a Cu alloy. More preferably, the lead terminal is made of a material having a core material such as Fe--Ni--Co alloy, Fe--Ni alloy, or Fe, and Cu surrounding it. In addition to efficient transmission, the thermal stress due to the difference in thermal expansion can be reduced when the lead terminals are fixed using a bonding material such as Ag (silver) solder. When the electrical signal transmitted through the lead terminal is a high-frequency signal, the skin effect causes the electrical signal to be transmitted only in the portion near the surface of the lead terminal, so Cu is provided only in the portion near the surface of the lead terminal. A high-frequency signal can be efficiently transmitted only by coating the surface of the lead terminal with a thin layer of Cu of about 0.5 to 5 μm by plating or the like.
　特開２０１４－３１３４号公報（特許文献２）は、セラミック枠体とリード端子とを有するパッケージを開示している。リード端子には、セラミック枠体のセラミックと熱膨張係数が近似するＦｅ－Ｎｉ－Ｃｏ系合金またはＦｅ－Ｎｉ系合金などからなる金属板が用いられている。また上記公報は、ボンディングワイヤでの接続、または、外気との接触による酸化もしくは硫化の防止などのために、表面に露出する金属部分に、Ｎｉめっき被膜およびＡｕ（金）めっき被膜を形成することを開示している。 Japanese Patent Laying-Open No. 2014-3134 (Patent Document 2) discloses a package having a ceramic frame and lead terminals. A metal plate made of Fe--Ni--Co alloy or Fe--Ni alloy having a coefficient of thermal expansion similar to that of the ceramic of the ceramic frame is used for the lead terminal. Further, in the above publication, a Ni-plated film and an Au (gold)-plated film are formed on the metal portion exposed to the surface for connection with a bonding wire or prevention of oxidation or sulfurization due to contact with the outside air. is disclosed.
　特開２０１５－８８７５７号公報（特許文献３）は、導電性リードを有するパッケージを開示している。導電性リードは、合金ではなく固体銅から形成されてよい。上記公報が主張するところによれば、合金ではなく固体銅を使用することによって、導電性が改善される。固体銅は、コスト上の利点も提供する。パッケージを含むシステムには、その製造のための様々な段階において、例えばＮｉＡｕ（ニッケル／金）またはＮｉＰｄＡｕ（ニッケル／パラジウム／金）を使用して、めっきをしてよい。 Japanese Patent Laying-Open No. 2015-88757 (Patent Document 3) discloses a package having conductive leads. The conductive leads may be formed from solid copper rather than an alloy. The publication alleges that the use of solid copper rather than alloys improves electrical conductivity. Solid copper also offers cost advantages. The system, including the package, may be plated using, for example, NiAu (nickel/gold) or NiPdAu (nickel/palladium/gold) at various stages of its manufacture.
　特開２０２０－１５５６９９号公報（特許文献４）は、樹脂を含む枠体と、それに取り付けられた端子電極と、純度９５．０ｗｔ％（重量パーセント）以上でＣｕを含有するヒートシンク板と、を有するパッケージを開示している。端子電極の材料は、Ｆｅ－Ｎｉ合金であってもよいが、好ましくは純度９０ｗｔ％以上でＣｕを含有する材料である。端子電極の表面には、ボンディングワイヤなどとの接合性を確保する目的で、ニッケルめっきと、当該ニッケルめっき上の金めっきとが施されてよい。 Japanese Patent Application Laid-Open No. 2020-155699 (Patent Document 4) has a frame containing resin, terminal electrodes attached thereto, and a heat sink plate containing Cu with a purity of 95.0 wt% (weight percent) or more. Disclose the package. The material of the terminal electrode may be an Fe—Ni alloy, but is preferably a material containing Cu with a purity of 90 wt % or more. Nickel plating and gold plating on the nickel plating may be applied to the surface of the terminal electrode for the purpose of ensuring bondability with a bonding wire or the like.
特開２００６－１２８５８８号公報JP 2006-128588 A 特開２０１４－３１３４号公報JP 2014-3134 A 特開２０１５－８８７５７号公報JP 2015-88757 A 特開２０２０－１５５６９９号公報JP 2020-155699 A
　上記特開２０１４－３１３４号公報（特許文献２）によれば、磁性体からなるリード端子上にＮｉめっきとＡｕめっきとが設けられた構成が開示されている。ここで、パッケージの製造コストを低減するためには、高価な材料を用いるＡｕめっきの厚みは、必要最小限であることが望ましい。上記公報に開示された構成においては、Ａｕめっきの厚みを薄くするほど、磁性体であるＮｉめっきが、より表面近くに位置することになる。磁性体は非磁性体に比して表皮効果の影響を大きく受ける。本発明者らの検討によれば、非常に高い周波数が用いられる場合において、パッケージに設けられたリード端子（リードフレーム）の、表皮効果に起因しての高周波損失が、有意な問題となり得る。近年、第５世代移動通信システム（５Ｇ）の導入などにともなって、３．６ＧＨｚ以上の高周波の利用が活発化してきており、その場合、この問題はより顕著となる。具体的には、５Ｇ向け基地局のアンプを構成するためのパワーモジュールを製造するためのパッケージにおいて、この問題は顕著となる。Ａｕめっきの厚みに関連したこの問題は、本発明者らが知る限り、パッケージの技術分野においてこれまで看過されていた。Ａｕめっきに代わって、またはそれと共にＰｄ（パラジウム）めっきが用いられる場合も、同様である。本発明者らはこの問題に着目し、そしてさらに検討を重ねることによって、後述する本発明の一の態様に想到した。 Japanese Patent Application Laid-Open No. 2014-3134 (Patent Document 2) discloses a configuration in which Ni plating and Au plating are provided on a lead terminal made of a magnetic material. Here, in order to reduce the manufacturing cost of the package, it is desirable that the thickness of the Au plating using an expensive material be the minimum necessary. In the structure disclosed in the above publication, the thinner the Au plating, the closer the Ni plating, which is a magnetic material, to the surface. Magnetic bodies are more affected by the skin effect than non-magnetic bodies. According to the study of the present inventors, when a very high frequency is used, the high frequency loss due to the skin effect of the lead terminal (lead frame) provided on the package can become a significant problem. In recent years, with the introduction of the 5th generation mobile communication system (5G), etc., the use of high frequencies of 3.6 GHz or higher has become active, and in that case, this problem will become more pronounced. Specifically, this problem becomes significant in packages for manufacturing power modules for configuring amplifiers for 5G base stations. As far as the inventors are aware, this problem related to the thickness of the Au plating has been overlooked in the packaging art. The same applies when Pd (palladium) plating is used in place of or together with Au plating. The inventors of the present invention focused on this problem and made further studies to arrive at one aspect of the present invention, which will be described later.
　特開２０２０－１５５６９９号公報（特許文献４）によれば、Ｃｕを主成分とし非磁性体からなる端子電極に、ＮｉめっきとＡｕめっきとを順に施すことが開示されている。ここで、パッケージの製造コストを低減するためには、高価な材料を用いるＡｕめっきの厚みは、必要最小限であることが望ましい。上記公報に開示された構成においては、Ａｕめっきの厚みを薄くするほど、磁性体であるＮｉめっきが、より表面近くに位置することになる。磁性体は非磁性体に比して表皮効果の影響を大きく受ける。本発明者らの検討によれば、非常に高い周波数が用いられる場合において、パッケージに設けられた端子電極（リードフレーム）の、表皮効果に起因しての高周波損失が、有意な問題となり得る。近年、５Ｇの導入などにともなって、３．６ＧＨｚ以上の非常に高い周波数の利用が活発化してきており、その場合、この問題はより顕著となる。具体的には、５Ｇ向け基地局のアンプを構成するためのパワーモジュールを製造するためのパッケージにおいて、この問題は顕著となる。Ａｕめっきの厚みに関連したこの問題は、本発明者らが知る限り、パッケージの技術分野においてこれまで看過されていた。Ａｕめっきに代わって、またはそれと共にＰｄ（パラジウム）めっきが用いられる場合も、同様である。本発明者らはこの問題に着目し、そしてさらに検討を重ねることによって、後述する本発明の他の態様に想到した。 Japanese Patent Application Laid-Open No. 2020-155699 (Patent Document 4) discloses that a terminal electrode made of a non-magnetic material containing Cu as a main component is sequentially plated with Ni and Au. Here, in order to reduce the manufacturing cost of the package, it is desirable that the thickness of the Au plating using an expensive material be the minimum necessary. In the structure disclosed in the above publication, the thinner the Au plating, the closer the Ni plating, which is a magnetic material, to the surface. Magnetic bodies are more affected by the skin effect than non-magnetic bodies. According to studies by the present inventors, when very high frequencies are used, high-frequency loss due to the skin effect of the terminal electrodes (lead frames) provided on the package can become a significant problem. In recent years, with the introduction of 5G, etc., the use of extremely high frequencies of 3.6 GHz or higher has become active, and in that case, this problem becomes more pronounced. Specifically, this problem becomes significant in packages for manufacturing power modules for configuring amplifiers for 5G base stations. As far as the inventors are aware, this problem related to the thickness of the Au plating has been overlooked in the packaging art. The same applies when Pd (palladium) plating is used in place of or together with Au plating. The inventors of the present invention focused on this problem, and by conducting further studies, came up with another aspect of the present invention, which will be described later.
　本開示は以上のような課題を解決するためになされたものであり、その目的は、製造コストと高周波損失とを同時に抑制することができる、パッケージおよびパワーモジュールを提供することである。 The present disclosure has been made to solve the above problems, and its purpose is to provide a package and a power module that can simultaneously suppress manufacturing costs and high-frequency loss.
　第１態様は、ヒートシンク板と、枠体と、リードフレームと、めっき層とを有するパッケージである。前記ヒートシンク板は、電子部品が実装されることになる実装面を有している。前記枠体は、前記ヒートシンク板に取り付けられており、前記ヒートシンク板の前記実装面を囲んでいる。前記リードフレームは、前記枠体に取り付けられており、磁性体からなる。前記めっき層は、前記リードフレームの少なくとも一部を覆っている。前記めっき層は、第１厚みを有する第１層と、第２厚みを有する第２層とを含む。前記第１層は、前記リードフレームの前記少なくとも一部を直接的に覆っており、非磁性体からなり、金およびパラジウムのいずれとも異なる金属からなる。前記第２層は、前記第１層を直接的に覆っており、金、パラジウムおよび銀の少なくともいずれかからなる。前記第１厚みと前記第２厚みとの合計が１μｍ以上であり、前記第２厚みが１μｍ未満である。 A first aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer. The heat sink plate has a mounting surface on which electronic components are to be mounted. The frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate. The lead frame is attached to the frame and is made of a magnetic material. The plating layer covers at least part of the lead frame. The plating layer includes a first layer having a first thickness and a second layer having a second thickness. The first layer directly covers the at least part of the lead frame, is made of a non-magnetic material, and is made of a metal other than gold and palladium. The second layer directly covers the first layer and is made of at least one of gold, palladium and silver. The sum of the first thickness and the second thickness is 1 μm or more, and the second thickness is less than 1 μm.
　第２態様は、第１態様に係るパッケージであって、前記金属は、銅および銀の少なくともいずれかを含む。 A second aspect is the package according to the first aspect, wherein the metal includes at least one of copper and silver.
　第３態様は、第１または第２態様に係るパッケージであって、前記第１厚みが０．５μｍ以上である。 A third aspect is the package according to the first or second aspect, wherein the first thickness is 0.5 μm or more.
　第４態様は、第１から第３態様のいずれかひとつに係るパッケージであって、前記めっき層は前記ヒートシンク板の前記実装面を覆っている。 A fourth aspect is the package according to any one of the first to third aspects, wherein the plating layer covers the mounting surface of the heat sink plate.
　第５態様は、第４態様に係るパッケージであって、前記ヒートシンク板は前記実装面と反対の底面を有しており、前記底面が前記めっき層によって覆われている。 A fifth aspect is the package according to the fourth aspect, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
　第６態様は、第４態様に係るパッケージであって、前記ヒートシンク板の表面は、前記枠体に面する部分と、他の部分とからなり、前記他の部分の全体が前記めっき層によって覆われている。 A sixth aspect is the package according to the fourth aspect, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer. It is
　第７態様は、第１から第６態様のいずれかひとつに係るパッケージと、前記ヒートシンク板の前記実装面上に実装された前記電子部品と、前記電子部品を封止するように前記パッケージに取り付けられた蓋体と、を有するパワーモジュールである。前記電子部品は３．６ＧＨｚ以上の動作周波数を有している。 A seventh aspect is the package according to any one of the first to sixth aspects, the electronic component mounted on the mounting surface of the heat sink plate, and the electronic component attached to the package so as to seal the electronic component. and a power module having a lid. The electronic component has an operating frequency of 3.6 GHz or higher.
　第８態様は、第７態様に係るパワーモジュールであって、前記パッケージの前記第２層は、前記第１層からの前記金属の原子拡散を有している。 An eighth aspect is the power module according to the seventh aspect, wherein the second layer of the package has atomic diffusion of the metal from the first layer.
　第９態様は、ヒートシンク板と、枠体と、リードフレームと、めっき層とを有するパッケージである。前記ヒートシンク板は、電子部品が実装されることになる実装面を有している。前記枠体は、前記ヒートシンク板に取り付けられており、前記ヒートシンク板の前記実装面を囲んでいる。前記リードフレームは、前記枠体に取り付けられており、非磁性体からなる。前記めっき層は、前記リードフレームの少なくとも一部を直接的に覆っており、金、パラジウムおよび銀の少なくともいずれかからなり、１μｍ未満の厚みを有している。 A ninth aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer. The heat sink plate has a mounting surface on which electronic components are to be mounted. The frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate. The lead frame is attached to the frame and is made of a non-magnetic material. The plating layer directly covers at least part of the lead frame, is made of at least one of gold, palladium and silver, and has a thickness of less than 1 μm.
　第１０態様は、第９態様に係るパッケージであって、前記リードフレームは銅または銅合金からなる。 A tenth aspect is the package according to the ninth aspect, wherein the lead frame is made of copper or a copper alloy.
　第１１態様は、第９または第１０態様に係るパッケージであって、前記めっき層は前記ヒートシンク板の前記実装面を覆っている。 An eleventh aspect is the package according to the ninth or tenth aspect, wherein the plating layer covers the mounting surface of the heat sink plate.
　第１２態様は、第１１態様に係るパッケージであって、前記ヒートシンク板は前記実装面と反対の底面を有しており、前記底面が前記めっき層によって覆われている。 A twelfth aspect is the package according to the eleventh aspect, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
　第１３態様は、第１１態様に係るパッケージであって、前記ヒートシンク板の表面は、前記枠体に面する部分と、他の部分とからなり、前記他の部分の全体が前記めっき層によって覆われている。 A thirteenth aspect is the package according to the eleventh aspect, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer. It is
　第１４態様は、第９から第１３態様のいずれかひとつに係るパッケージと、前記ヒートシンク板の前記実装面上に実装された前記電子部品と、前記電子部品を封止するように前記パッケージに取り付けられた蓋体と、を有するパワーモジュールである。前記電子部品は３．６ＧＨｚ以上の動作周波数を有している。 A fourteenth aspect is the package according to any one of the ninth to thirteenth aspects, the electronic component mounted on the mounting surface of the heat sink plate, and the electronic component attached to the package so as to seal the electronic component. and a power module having a lid. The electronic component has an operating frequency of 3.6 GHz or higher.
　第１５態様は、第１４態様に係るパワーモジュールであって、前記パッケージの前記めっき層は、前記リードフレームからの銅原子拡散を有している。 A fifteenth aspect is the power module according to the fourteenth aspect, wherein the plating layer of the package has copper atom diffusion from the lead frame.
　第１６態様は、ヒートシンク板と、枠体と、リードフレームと、めっき層とを有するパッケージである。前記ヒートシンク板は、電子部品が実装されることになる実装面を有している。前記枠体は、前記ヒートシンク板に取り付けられており、前記ヒートシンク板の前記実装面を囲んでいる。前記リードフレームは、前記枠体に取り付けられており、磁性体からなる。前記めっき層は、前記リードフレームの少なくとも一部を直接的に覆っており、銀からなり、１μｍ以上の厚みを有しており、露出された表面を有している。 A sixteenth aspect is a package having a heat sink plate, a frame, a lead frame, and a plating layer. The heat sink plate has a mounting surface on which electronic components are to be mounted. The frame is attached to the heat sink plate and surrounds the mounting surface of the heat sink plate. The lead frame is attached to the frame and is made of a magnetic material. The plating layer directly covers at least a portion of the lead frame, is made of silver, has a thickness of 1 μm or more, and has an exposed surface.
　上記の一の態様に従うパッケージによれば、第１に、高価な材料である金、パラジウムおよび銀の少なくともいずれかからなる第２層の厚みである第２の厚みが１μｍ未満である。これにより、パッケージの製造コストを抑制することができる。第２に、第１層およびそれを直接的に覆う第２層が、リードフレームの表面上において、厚み１μｍ以上の非磁性膜を構成する。これにより、リードフレームを流れる高周波電流の、表皮効果に起因した電気的損失が、抑制される。以上から、パッケージの製造コストと、高周波損失とを、同時に抑制することができる。 According to the package according to the above aspect, firstly, the second thickness, which is the thickness of the second layer made of at least one of gold, palladium and silver, which are expensive materials, is less than 1 μm. Thereby, the manufacturing cost of the package can be suppressed. Second, the first layer and the second layer directly covering it form a non-magnetic film with a thickness of 1 μm or more on the surface of the lead frame. This suppresses the electrical loss of the high-frequency current flowing through the lead frame due to the skin effect. As described above, the manufacturing cost of the package and the high frequency loss can be suppressed at the same time.
　上記の他の態様に従うパッケージによれば、第１に、高価な材料である金、パラジウムおよび銀の少なくともいずれかからなるめっき層の厚みが１μｍ未満である。これにより、パッケージの製造コストを抑制することができる。第２に、めっき層と、非磁性体からなるリードフレームの、めっき層によって覆われた部分とによって、リードフレームの表面に沿って、十分な厚みを有する非磁性導体領域が確保される。これにより、リードフレームを流れる高周波電流の、表皮効果に起因した電気的損失が、抑制される。以上から、パッケージの製造コストと、高周波損失とを、同時に抑制することができる。 According to the package according to the other aspect described above, first, the thickness of the plated layer made of at least one of gold, palladium, and silver, which are expensive materials, is less than 1 μm. Thereby, the manufacturing cost of the package can be suppressed. Second, a nonmagnetic conductor region having a sufficient thickness is secured along the surface of the leadframe by the plating layer and the portion of the leadframe made of a nonmagnetic material covered by the plating layer. This suppresses the electrical loss of the high-frequency current flowing through the lead frame due to the skin effect. As described above, the manufacturing cost of the package and the high frequency loss can be suppressed at the same time.
　この発明の目的、特徴、態様、および利点は、以下の詳細な説明と添付図面とによって、より明白となる。 The objects, features, aspects, and advantages of the present invention will become more apparent with the following detailed description and accompanying drawings.
実施の形態１におけるパワーモジュールの構成を概略的に示す上面図である。2 is a top view schematically showing the configuration of the power module according to Embodiment 1; FIG. 図１の線ＩＩ－ＩＩに沿う概略的な断面図である。2 is a schematic cross-sectional view along line II-II of FIG. 1; FIG. 実施の形態１におけるパッケージの構成を概略的に示す上面図である。2 is a top view schematically showing the configuration of the package in Embodiment 1; FIG. 図３の線ＩＶ－ＩＶに沿う概略的な断面図である。Figure 4 is a schematic cross-sectional view along line IV-IV of Figure 3; 図４の領域Ｖの拡大図である。5 is an enlarged view of region V of FIG. 4; FIG. 各種材料にとっての周波数と、表皮効果における表皮深さとの関係を概略的に示すグラフ図である。FIG. 4 is a graphical representation schematically showing the relationship between frequency and skin depth in the skin effect for various materials; 実施の形態２におけるパッケージの構成を概略的に示す断面図である。FIG. 10 is a cross-sectional view schematically showing the configuration of a package in Embodiment 2; 実施の形態３におけるパワーモジュールの構成を概略的に示す断面図である。FIG. 11 is a cross-sectional view schematically showing the configuration of a power module according to Embodiment 3; 実施の形態３におけるパッケージの構成を概略的に示す断面図である。FIG. 11 is a cross-sectional view schematically showing the configuration of a package in Embodiment 3; 図９の領域Ｘの拡大図である。FIG. 10 is an enlarged view of region X in FIG. 9; 実施の形態４におけるパッケージの構成を概略的に示す断面図である。FIG. 12 is a cross-sectional view schematically showing the structure of a package in Embodiment 4; 実施の形態５におけるパッケージの構成を概略的に示す断面図である。FIG. 14 is a cross-sectional view schematically showing the configuration of a package in Embodiment 5; 実施の形態６におけるパッケージの構成を概略的に示す断面図である。FIG. 20 is a cross-sectional view schematically showing the configuration of a package in Embodiment 6;
　以下、図面に基づいて実施の形態について説明する。なお、以下の図面には、説明の便宜上、ＸＹＺ直交座標系が付されていることがある。また、以下の図面において同一または相当する部分には同一の参照番号を付しており、明細書においてその説明は繰返さないことがある。また、用語「金属」は、特段の記載をともなわない限り、純金属および合金のいずれをも意味し得る。 Embodiments will be described below based on the drawings. For the convenience of explanation, the following drawings may include an XYZ orthogonal coordinate system. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and the description thereof may not be repeated in the specification. Also, the term "metal" can mean both pure metals and alloys, unless otherwise specified.
　＜実施の形態１＞
　図１は、実施の形態１におけるパワーモジュール９０１の構成を概略的に示す上面図である。図２は、図１の線ＩＩ－ＩＩに沿う概略的な断面図である。パワーモジュール９０１は、キャビティＣＶを有するパッケージ１０１と、キャビティＣＶ内においてパッケージ１０１上に実装されたパワー半導体素子２００（電子部品）と、パワー半導体素子２００を封止するようにパッケージ１０１に取り付けられた蓋体３００とを有している。またパワーモジュール９０１は、接着層４６と、接合層４２と、ボンディングワイヤ２０５（配線部材）とを有している。 <Embodiment 1>
FIG. 1 is a top view schematically showing the configuration of power module 901 according to Embodiment 1. FIG. FIG. 2 is a schematic cross-sectional view along line II-II of FIG. The power module 901 includes a package 101 having a cavity CV, a power semiconductor element 200 (electronic component) mounted on the package 101 within the cavity CV, and attached to the package 101 so as to seal the power semiconductor element 200. It has a lid 300 . The power module 901 also has an adhesive layer 46, a bonding layer 42, and bonding wires 205 (wiring members).
　パワー半導体素子２００は高周波用半導体素子であり、よってパワーモジュール９０１は高周波モジュールである。パワー半導体素子２００は、３．６ＧＨｚ以上の動作周波数を有していてよい。３．６ＧＨｚ程度以上の高い動作周波数を用いるためには、パワー半導体素子２００がワイドバンドギャップ半導体を用いていることが好ましい。例えば、パワー半導体素子２００はＧａＮ（窒化ガリウム）トランジスタである。なおパワー半導体素子２００の動作周波数は、６．０ＧＨｚ以下であってよい。 The power semiconductor element 200 is a high frequency semiconductor element, and therefore the power module 901 is a high frequency module. The power semiconductor device 200 may have an operating frequency of 3.6 GHz or higher. In order to use a high operating frequency of about 3.6 GHz or higher, it is preferable that the power semiconductor device 200 uses a wide bandgap semiconductor. For example, the power semiconductor device 200 is a GaN (gallium nitride) transistor. Note that the operating frequency of the power semiconductor device 200 may be 6.0 GHz or less.
　詳しくは後述するが、パッケージ１０１は、キャビティＣＶに面する実装面ＲＭを有するヒートシンク板５０を含む。パワー半導体素子２００は実装面ＲＭ上に実装されている。実装面ＲＭとパワー半導体素子２００とは、熱硬化性樹脂と金属とを含有する接合層４２を介して互いに接合されていることが好ましい。接合層４２の熱硬化性樹脂は、エポキシ樹脂を含むことが好ましい。接合層４２の金属は、銀を含むことが好ましい。接合層４２は、熱硬化性樹脂を含まずに金属だけで構成されていてもよい。なお、パワー半導体素子２００に加えて他の電子部品（図示せず）が実装面ＲＭ上に配置されていてよい。 Although details will be described later, the package 101 includes a heat sink plate 50 having a mounting surface RM facing the cavity CV. Power semiconductor element 200 is mounted on mounting surface RM. Mounting surface RM and power semiconductor element 200 are preferably bonded to each other via bonding layer 42 containing thermosetting resin and metal. The thermosetting resin of the bonding layer 42 preferably contains an epoxy resin. The metal of the bonding layer 42 preferably contains silver. The bonding layer 42 may be composed only of metal without containing a thermosetting resin. In addition to power semiconductor element 200, other electronic components (not shown) may be arranged on mounting surface RM.
　接着層４６はパッケージ１０１と蓋体３００とを互いに接着している。これにより、パワー半導体素子２００は、キャビティＣＶ内に封止されている。よってパワー半導体素子２００は、高い気密性で、水蒸気その他の大気中のガスが侵入しないように外部環境から保護されている。 The adhesive layer 46 bonds the package 101 and the lid 300 together. Thereby, the power semiconductor element 200 is sealed within the cavity CV. Therefore, the power semiconductor element 200 is highly airtight and protected from the external environment so that water vapor and other gases in the atmosphere do not enter.
　ボンディングワイヤ２０５は、パワー半導体素子２００と、パッケージ１０１のリードフレーム９１（電極端子）とを、互いにつないでいる。これにより、パワー半導体素子２００と、リードフレーム９１とが、互いに電気的に接続されている。なお、パワー半導体素子２００とリードフレーム９１との間の電気的接続は、ボンディングワイヤ２０５とは異なる配線部材よって確保されてもよく、その場合、ボンディングワイヤ２０５は必ずしも必要ではない。 The bonding wires 205 connect the power semiconductor element 200 and the lead frame 91 (electrode terminals) of the package 101 to each other. Thus, power semiconductor element 200 and lead frame 91 are electrically connected to each other. The electrical connection between power semiconductor element 200 and lead frame 91 may be secured by a wiring member other than bonding wire 205, in which case bonding wire 205 is not necessarily required.
　図３は、実施の形態１におけるパッケージ１０１の構成を概略的に示す上面図である。図４は、図３の線ＩＶ－ＩＶに沿う概略的な断面図である。図５は、図４の領域Ｖの拡大図である。パッケージ１０１は、パワーモジュール９０１（図１および図２）の製造用に用いられることになる部品である。パワーモジュール９０１の製造において、パッケージ１０１は、蓋体３００（図２）が取り付けられることによって、封止されたキャビティＣＶを構成することになる。パッケージ１０１は、ヒートシンク板５０と、枠体８１と、リードフレーム９１と、めっき層２０とを有している。本実施の形態１においてはさらに、パッケージ１０１は、樹脂接着層６１と、ヒートシンク接着層４１と、追加接着層６２と、追加枠体８２とを有している。 FIG. 3 is a top view schematically showing the configuration of the package 101 according to Embodiment 1. FIG. FIG. 4 is a schematic cross-sectional view along line IV-IV of FIG. FIG. 5 is an enlarged view of area V in FIG. Package 101 is a component that will be used for the manufacture of power module 901 (FIGS. 1 and 2). In manufacturing the power module 901, the package 101 forms a sealed cavity CV by attaching the lid 300 (FIG. 2). The package 101 has a heat sink plate 50 , a frame 81 , a lead frame 91 and a plating layer 20 . In Embodiment 1, package 101 further includes resin adhesive layer 61 , heat sink adhesive layer 41 , additional adhesive layer 62 , and additional frame 82 .
　ヒートシンク板５０は、パワー半導体素子２００が実装されることになる実装面ＲＭを有している。図３および図４においては、実装面ＲＭ上にパワー半導体素子２００が未だ実装されておらず、よって実装面ＲＭは露出されている。枠体８１は、ヒートシンク板５０に取り付けられており、平面視（ＸＹ面における視野）においてヒートシンク板５０の実装面ＲＭを囲んでいる。ヒートシンク板５０は金属材料からなり、この金属材料は複合材料および非複合材料のいずれであってもよい。複合材料は、厚み方向（図４における縦方向）に異種材料膜が積層されることによって構成された積層膜であってよい。これら異種材料膜は、典型的には、Ｃｕ膜およびＭｏ（モリブデン）膜である。非複合材料は、純度９５．０ｗｔ％以上で銅を含有することが好ましく、純度９９．８ｗｔ％以上で銅を含有する非複合材料であることがより好ましい。なお、耐熱性の観点からは、ヒートシンク板５０の銅含有量は、１００ｗｔ％未満であることが好ましい。 The heat sink plate 50 has a mounting surface RM on which the power semiconductor element 200 is mounted. In FIGS. 3 and 4, power semiconductor element 200 is not yet mounted on mounting surface RM, and thus mounting surface RM is exposed. The frame 81 is attached to the heatsink plate 50 and surrounds the mounting surface RM of the heatsink plate 50 in plan view (field of view in the XY plane). The heat sink plate 50 is made of a metallic material, which can be either composite or non-composite. The composite material may be a laminated film configured by laminating different material films in the thickness direction (longitudinal direction in FIG. 4). These different material films are typically a Cu film and a Mo (molybdenum) film. The non-composite material preferably contains copper with a purity of 95.0 wt % or higher, more preferably a non-composite material containing copper with a purity of 99.8 wt % or higher. From the viewpoint of heat resistance, the copper content of the heat sink plate 50 is preferably less than 100 wt%.
　リードフレーム９１は、枠体８１に樹脂接着層６１によって取り付けられている。リードフレーム９１は、平面視（ＸＹ面）において、枠体８１の外縁から外側へ突出した突出部と、この突出部より内側の根本部とを有している。根本部は、枠体８１に樹脂接着層６１を介して接着されている。リードフレーム９１は、磁性体からなり、この磁性体は、例えば、Ｆｅ－Ｎｉ合金（ＦｅおよびＮｉを含む合金）またはＦｅ－Ｎｉ－Ｃｏ合金（Ｆｅ、ＮｉおよびＣｏを含む合金）である。なお、リードフレーム９１には磁性体めっき膜（例えばＮｉめっき膜）が施されていてもよく、この磁性体めっき膜は、磁性体からなるリードフレーム９１の一部分とみなす。 The lead frame 91 is attached to the frame 81 with the resin adhesive layer 61 . The lead frame 91 has a protruding portion that protrudes outward from the outer edge of the frame 81 and a root portion inside the protruding portion in a plan view (XY plane). The root portion is adhered to the frame body 81 via the resin adhesive layer 61 . The lead frame 91 is made of a magnetic material, such as an Fe--Ni alloy (an alloy containing Fe and Ni) or an Fe--Ni--Co alloy (an alloy containing Fe, Ni and Co). Note that the lead frame 91 may be provided with a magnetic plated film (for example, a Ni plated film), and this magnetic plated film is regarded as part of the lead frame 91 made of a magnetic material.
　めっき層２０は、リードフレーム９１の少なくとも一部を覆っている。リードフレーム９１のうち少なくとも上記突出部は、めっき層２０によって覆われていることが好ましい。めっき層２０は、図４に示されているようにリードフレーム９１の全部を覆っていてもよい。 The plating layer 20 covers at least part of the lead frame 91 . At least the protruding portion of the lead frame 91 is preferably covered with the plating layer 20 . The plating layer 20 may cover the entire leadframe 91 as shown in FIG.
　めっき層２０（図５）は、第１厚みを有する第１層２１と、第２厚みを有する第２層２２とを含む。第１層２１は、リードフレーム９１の少なくとも一部（本実施の形態においては全部）を直接的に覆っている。第１層２１は、非磁性体からなり、ＡｕおよびＰｄのいずれとも異なる金属からなる。第１層２１をなすこの金属は、ＣｕおよびＡｇの少なくともいずれかを含み、好ましくはＣｕである。第１層２１の材料としては、第２層２２の材料とは異なる材料が、材料コストを削減することができるように選択される。第２層２２は、第１層２１を直接的に覆っており、Ａｕ、ＰｄおよびＡｇの少なくともいずれかからなる。このような第２層２２を設けることにより、第１層２１の表面が酸化や硫化などにより変質することを抑制できる。酸化だけでなく硫化の抑制も重要な場合は、第２層２２は、好ましくは、ＡｕおよびＰｄの少なくともいずれかからなる。一方、第２層２２の材料コストの観点では、第２層２２は、好ましくは少なくとも部分的にＡｇからなり、より好ましくは全体的にＡｇからなる。第２層２２は、第１層２１からの上記金属（例えばＣｕ）の原子拡散を有していてよい。また、第１層２１は、第２層２２からの原子拡散を有していてよい。第１厚みと第２厚みとの合計、言い換えればめっき層２０の厚み、は１μｍ以上である。第２厚みは１μｍ未満である。第１厚みは０．５μｍ以上であることが好ましい。また第２厚みは０．０１μｍ以上であることが好ましい。第２厚みがこの程度であれば、めっき層２０の表面が酸化してワイヤボンディング性や接合層４２の濡れ性が阻害されることを防止できる。第２層２２は、積層膜であってよい。具体的には、第２層２２は、第１層２１を直接的に覆うＰｄ膜と、このＰｄ膜を直接的に覆うＡｕ膜とによって構成されていてよい。 The plating layer 20 (Fig. 5) includes a first layer 21 having a first thickness and a second layer 22 having a second thickness. The first layer 21 directly covers at least part (all in this embodiment) of the lead frame 91 . The first layer 21 is made of a non-magnetic material, and is made of a metal different from both Au and Pd. This metal forming the first layer 21 contains at least one of Cu and Ag, preferably Cu. A material different from the material of the second layer 22 is selected as the material of the first layer 21 so that the material cost can be reduced. The second layer 22 directly covers the first layer 21 and is made of at least one of Au, Pd and Ag. By providing such a second layer 22, it is possible to prevent the surface of the first layer 21 from being deteriorated due to oxidation, sulfurization, or the like. If suppression of not only oxidation but also sulfurization is important, the second layer 22 preferably consists of at least one of Au and Pd. On the other hand, from the point of view of the material cost of the second layer 22, the second layer 22 preferably consists at least partially of Ag, more preferably entirely of Ag. The second layer 22 may have atomic diffusions of the metal (eg Cu) from the first layer 21 . The first layer 21 may also have atomic diffusion from the second layer 22 . The sum of the first thickness and the second thickness, in other words, the thickness of the plating layer 20 is 1 μm or more. The second thickness is less than 1 μm. The first thickness is preferably 0.5 μm or more. Also, the second thickness is preferably 0.01 μm or more. If the second thickness is at this level, it is possible to prevent the surface of the plating layer 20 from being oxidized and impairing the wire bonding properties and the wettability of the bonding layer 42 . The second layer 22 may be a laminated film. Specifically, the second layer 22 may be composed of a Pd film directly covering the first layer 21 and an Au film directly covering the Pd film.
　めっき層２０は、リードフレーム９１だけでなく、ヒートシンク板５０の少なくとも一部、特に実装面ＲＭ、も覆っていてよい。さらに、図４に示されているように、ヒートシンク板５０は実装面ＲＭと反対の底面を有しており、当該底面がめっき層２０によって覆われていてよい。ヒートシンク板５０の表面は、枠体（本実施の形態においては枠体８１）に面する部分と、他の部分（以下、「露出面」とも称する）と、からなる。図４においては、ヒートシンク板５０の表面のうち、ヒートシンク接着層４１に覆われた部分以外のすべての部分が露出面に対応している。この露出面の全体がめっき層２０によって覆われていてよい。また、めっき層２０は、図４に示されているように、ヒートシンク板５０の全部を覆っていてもよい。なお変形例として、ヒートシンク板５０には、めっき層２０とは異なるめっき層が設けられていてよい。 The plating layer 20 may cover not only the lead frame 91 but also at least a portion of the heat sink plate 50, especially the mounting surface RM. Furthermore, as shown in FIG. 4 , the heat sink plate 50 has a bottom surface opposite to the mounting surface RM, and the bottom surface may be covered with the plating layer 20 . The surface of the heat sink plate 50 consists of a portion facing the frame (frame 81 in this embodiment) and other portions (hereinafter also referred to as "exposed surface"). In FIG. 4, of the surface of the heatsink plate 50, all the portions other than the portion covered with the heatsink adhesive layer 41 correspond to the exposed surface. The entire exposed surface may be covered with the plating layer 20 . Alternatively, the plating layer 20 may cover the entire heat sink plate 50 as shown in FIG. As a modification, the heat sink plate 50 may be provided with a plating layer different from the plating layer 20 .
　枠体８１は樹脂（第１の樹脂）を含有していることが好ましい。この樹脂は、熱可塑性樹脂であることが好ましく、例えば液晶ポリマーである。この樹脂中には無機フィラー（第１の無機フィラー）が分散されていることが好ましい。この無機フィラーは、好ましくは、繊維状粒子および板状粒子の少なくともいずれかを含む。形状が繊維状または板状であることによって、枠体８１が射出成形技術等によって形成される際に、フィラーが樹脂の流動を阻害することが抑制される。このような無機フィラーの材料としては、例えば、シリカガラス繊維、アルミナ繊維、炭素繊維、タルク（３ＭｇＯ・４ＳｉＯ２・Ｈ２Ｏ）、ウォラストナイト、マイカ、グラファイト、炭酸カルシウム、ドロマイト、ガラスフレーク、ガラスビーズ、硫酸バリウム、酸化チタンが用いられる。タルクからなる無機フィラーの平板上での大きさは、例えば、粒径１μｍ～５０μｍである。ここで粒径は、樹脂の断面観察によって得られた長径の算術平均値である。無機フィラーの含有量は３０ｗｔ％～７０ｗｔ％であることが好ましい。ヒートシンク板５０の熱膨張係数が銅のものまたはそれに近い場合、銅の熱膨張係数に鑑みて、無機フィラーの熱膨張係数は１７ｐｐｍ／Ｋ以下が好ましい。枠体８１の材料は、２６０℃２時間の熱処理に対して耐熱性を有していることが好ましい。 The frame 81 preferably contains resin (first resin). The resin is preferably a thermoplastic resin, such as a liquid crystal polymer. An inorganic filler (first inorganic filler) is preferably dispersed in this resin. This inorganic filler preferably contains at least one of fibrous particles and plate-like particles. The fibrous or plate-like shape prevents the filler from obstructing the flow of the resin when the frame 81 is formed by an injection molding technique or the like. Materials for such inorganic fillers include, for example, silica glass fiber, alumina fiber, carbon fiber, talc ( 3MgO.4SiO.sub.2.H.sub.2O ), wollastonite, mica, graphite, calcium carbonate, dolomite, glass flakes, Glass beads, barium sulfate, and titanium oxide are used. The size of the inorganic filler made of talc on a flat plate is, for example, a particle size of 1 μm to 50 μm. Here, the particle size is the arithmetic mean value of the major diameter obtained by cross-sectional observation of the resin. The content of inorganic filler is preferably 30 wt % to 70 wt %. When the thermal expansion coefficient of the heat sink plate 50 is that of copper or close to it, the thermal expansion coefficient of the inorganic filler is preferably 17 ppm/K or less in view of the thermal expansion coefficient of copper. The material of the frame body 81 preferably has heat resistance to heat treatment at 260° C. for 2 hours.
　樹脂接着層６１は、枠体８１の材料とは異なる材料からなる。樹脂接着層６１は、枠体８１の樹脂（第１の樹脂）と異なる樹脂（第２の樹脂）を含有している。樹脂接着層６１の樹脂は、耐熱性と、硬化前の高流動性との観点で、熱硬化性樹脂であることが好ましく、例えば、エポキシ樹脂である。樹脂接着層６１の樹脂中には無機フィラーが分散されていてよい。 The resin adhesive layer 61 is made of a material different from that of the frame 81 . The resin adhesive layer 61 contains a resin (second resin) different from the resin (first resin) of the frame 81 . From the viewpoint of heat resistance and high fluidity before curing, the resin of the resin adhesive layer 61 is preferably a thermosetting resin, such as an epoxy resin. An inorganic filler may be dispersed in the resin of the resin adhesive layer 61 .
　追加枠体８２は、樹脂接着層６１によってリードフレーム９１が取り付けられた枠体８１上に、追加接着層６２を介して取り付けられている。枠体８１と追加枠体８２との間をリードフレーム９１が通っている。追加枠体８２は、樹脂を含有していることが好ましい。追加枠体８２の材料は枠体８１の材料と同じであってよい。また追加接着層６２の材料は樹脂接着層６１と同じであってよい。 The additional frame 82 is attached via the additional adhesive layer 62 on the frame 81 to which the lead frame 91 is attached by the resin adhesive layer 61 . A lead frame 91 passes between the frame 81 and the additional frame 82 . The additional frame 82 preferably contains resin. The material of the additional frame 82 may be the same as the material of the frame 81 . Further, the material of the additional adhesive layer 62 may be the same as that of the resin adhesive layer 61 .
　ヒートシンク接着層４１は、枠体８１と、ヒートシンク板５０とを互いに接着している。ヒートシンク接着層４１によってヒートシンク板５０と枠体８１との間の気密性が確保されている。 The heat sink adhesive layer 41 adheres the frame 81 and the heat sink plate 50 to each other. The heat sink adhesive layer 41 ensures airtightness between the heat sink plate 50 and the frame 81 .
　ヒートシンク接着層４１、樹脂接着層６１および追加接着層６２の各々による気密性は、２６０℃２時間の熱処理に対して耐熱性を有していることが好ましい。２６０℃２時間の熱処理に対して耐熱性を有していれば、熱硬化性樹脂と金属とを含有するペースト状の接着剤を用いてのパワー半導体素子２００（図２）の実装工程における典型的な熱処理への耐熱性が確保される。 The airtightness of each of the heat sink adhesive layer 41, resin adhesive layer 61, and additional adhesive layer 62 preferably has heat resistance to heat treatment at 260°C for two hours. If it has heat resistance to heat treatment at 260° C. for 2 hours, it is typical in the mounting process of the power semiconductor element 200 (FIG. 2) using a paste adhesive containing a thermosetting resin and a metal. The heat resistance to general heat treatment is ensured.
　枠体８１は、ヒートシンク板５０にヒートシンク接着層４１を介して支持されている。枠体８１は、図４において、例えば、０．３ｍｍ程度の厚み（図４における縦方向の寸法）と、２ｍｍ程度の全幅（図４における横方向の寸法）とを有している。なお追加枠体８２の厚みおよび全幅も同様であってよい。全幅とは枠体を構成する一つの辺の幅をいう。 The frame 81 is supported by the heat sink plate 50 via the heat sink adhesive layer 41 . In FIG. 4, the frame 81 has, for example, a thickness of about 0.3 mm (dimension in the vertical direction in FIG. 4) and an overall width of about 2 mm (dimension in the horizontal direction in FIG. 4). The thickness and overall width of the additional frame 82 may also be the same. Full width refers to the width of one side that constitutes the frame.
　ヒートシンク接着層４１は枠体８１とヒートシンク板５０とを互いに接着している。ヒートシンク接着層４１の材料は、枠体８１の材料と異なる材料からなる。ヒートシンク接着層４１の材料は、樹脂接着層６１の材料と同じであってよい。ヒートシンク接着層４１の樹脂は、耐熱性と、硬化前の高流動性との観点で、熱硬化性樹脂であることが好ましく、例えばエポキシ樹脂である。 The heat sink adhesive layer 41 adheres the frame 81 and the heat sink plate 50 to each other. The material of the heat sink adhesive layer 41 is different from the material of the frame 81 . The material of the heat sink adhesive layer 41 may be the same as the material of the resin adhesive layer 61 . From the viewpoint of heat resistance and high fluidity before curing, the resin of the heat sink adhesive layer 41 is preferably a thermosetting resin, such as an epoxy resin.
　ヒートシンク接着層４１の樹脂中には無機フィラーが分散されていることが好ましい。この無機フィラーは、好ましくはシリカガラスおよびシリカの少なくともいずれかを含有し、より好ましくはシリカガラスからなる。ここでシリカとは結晶性シリカと同義である。典型的には、シリカガラスの熱膨張係数は０．５ｐｐｍ／Ｋ程度であり、結晶性シリカの熱膨張係数は１５ｐｐｍ／Ｋ程度であり、よって、無機フィラーの熱膨張係数を１７ｐｐｍ／Ｋ以下とすることができる。このことは、ヒートシンク接着層４１の樹脂としてエポキシ樹脂またはフッ素樹脂が用いられる場合、特に望まれる。この場合、無機フィラーの含有量は５０ｗｔ％～９０ｗｔ％であることが好ましい。シリカガラスおよびシリカの少なくともいずれかに代わって、またはそれと共に、アルミナ、水酸化アルミニウム、タルク、酸化鉄、ウォラストナイト、炭酸カルシウム、マイカ、酸化チタン、炭素繊維の少なくともいずれかが用いられてもよい。無機フィラーの形状は、例えば、球状、繊維状、または板状である。一方、ヒートシンク接着層４１の樹脂としてシリコーン樹脂が用いられる場合は、枠体８１がゴム弾性を有するので、無機フィラーの熱膨張係数の制約はほぼ無視できる。この場合、無機フィラーの含有量は、ヒートシンク接着層４１の流動性制御等の観点で調整されてよく、１ｗｔ％～１０ｗｔ％であることが好ましい。硬化前のヒートシンク接着層４１の流動性を確保する観点では、粒径１μｍ～５０μｍの球状シリカガラス（非結晶性シリカ）が最適である。 An inorganic filler is preferably dispersed in the resin of the heat sink adhesive layer 41 . This inorganic filler preferably contains at least one of silica glass and silica, and more preferably consists of silica glass. Here, silica is synonymous with crystalline silica. Typically, the thermal expansion coefficient of silica glass is about 0.5 ppm/K, and the thermal expansion coefficient of crystalline silica is about 15 ppm/K. can do. This is especially desired when epoxy resin or fluororesin is used as the resin of the heat sink adhesive layer 41 . In this case, the content of the inorganic filler is preferably 50 wt % to 90 wt %. At least one of alumina, aluminum hydroxide, talc, iron oxide, wollastonite, calcium carbonate, mica, titanium oxide, and carbon fiber may be used instead of or together with at least one of silica glass and silica. good. The shape of the inorganic filler is, for example, spherical, fibrous, or plate-like. On the other hand, when a silicone resin is used as the resin of the heat sink adhesive layer 41, the frame body 81 has rubber elasticity, so the limitation of the thermal expansion coefficient of the inorganic filler can be almost ignored. In this case, the content of the inorganic filler may be adjusted from the viewpoint of fluidity control of the heat sink adhesive layer 41, and is preferably 1 wt % to 10 wt %. From the viewpoint of securing fluidity of the heat sink adhesive layer 41 before curing, spherical silica glass (amorphous silica) having a particle size of 1 μm to 50 μm is optimal.
　図６は、各種材料にとっての周波数ｆと、表皮効果における表皮深さｔとの関係を概略的に示すグラフ図である。図中、「Ｆｅ－Ｎｉ」は、具体的には、４２アロイである。このグラフからわかるように、Ａｕ、ＣｕおよびＰｄなどの非磁性体の表皮深さｔに比して、ＮｉおよびＦｅ－Ｎｉなどの磁性体の表皮深さｔは顕著に小さい。言い換えれば、磁性体は非磁性体に比して、表皮効果の影響を大きく受ける。特に、ｆ＝３．６ＧＨｚおよび６．０ＧＨｚでの表皮深さｔは、以下の表１のとおりである。 FIG. 6 is a graph diagram schematically showing the relationship between the frequency f for various materials and the skin depth t in the skin effect. In the figure, "Fe--Ni" is specifically 42 alloy. As can be seen from this graph, the skin depth t of magnetic materials such as Ni and Fe—Ni is significantly smaller than the skin depth t of non-magnetic materials such as Au, Cu and Pd. In other words, magnetic bodies are more affected by the skin effect than non-magnetic bodies. Specifically, the skin depths t at f=3.6 GHz and 6.0 GHz are shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　磁性体としては、１×１０－４～１×１０－１[Ｈ／ｍ]程度の透磁率を有する金属を用いることができ、例えば、ＮｉおよびＮｉ－Ｆｅ合金（例えば４２アロイ）の少なくともいずれかを用いることができる。一方、非磁性体としては、１×１０－６～１×１０－５[Ｈ／ｍ]程度の透磁率を有する金属を用いることができ、例えば、Ａｕ、Ｐｄ、ＣｕおよびＡｇの少なくともいずれかを用いることができる。図６および表１に示す表皮深さｔの計算に用いた物性値（抵抗率と透磁率）を、以下の表２に示す。 As the magnetic material, a metal having a magnetic permeability of about 1×10 −4 to 1×10 −1 [H/m] can be used. or can be used. On the other hand, as the non-magnetic material, a metal having a magnetic permeability of about 1×10 −6 to 1×10 −5 [H/m] can be used. can be used. Table 2 below shows the physical property values (resistivity and magnetic permeability) used to calculate the skin depth t shown in FIG. 6 and Table 1.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表皮深さｔは、表２の物性値を用いて、以下の式
　　ｔ ＝ ｛（２ × ρ）／（２ × π × ｆ × μ）｝１／２
により算出されている。ここで、ρは抵抗率、ｆは周波数、μは透磁率である。 The skin depth t is obtained by the following formula t = {(2 × ρ)/(2 × π × f × μ)} 1/2 using the physical property values in Table 2
Calculated by where ρ is resistivity, f is frequency, and μ is magnetic permeability.
　本実施の形態におけるめっき層２０は、例えば、Ａｕ／Ｐｄ／Ｃｕの構成を有する積層膜であり、Ａｕ、ＰｄおよびＣｕのいずれも、比較的大きな表皮深さｔを有している。具体的には、ｆ＝３．６ＧＨｚの高周波においても、おおよそ１μｍの表皮深さが確保される。よって、めっき層２０の厚みが１μｍ以上であれば、３．６ＧＨｚの高周波においても、リードフレームによる電気的経路の表皮深さを１μｍ程度確保することができる。本発明者らの検討によれば、表皮深さをこの程度確保することができれば、高周波損失を十分に低く抑えることができる。また、より高い周波数であっても、例えばｆ＝６．０ＧＨｚ程度以下の範囲であれば、上記の表１に示すように表皮深さｔが極端には小さくなっておらず、よって高周波損失を許容範囲内に抑えることができる場合が多いと考えられる。 The plating layer 20 in the present embodiment is, for example, a laminated film having a configuration of Au/Pd/Cu, and all of Au, Pd and Cu have a relatively large skin depth t. Specifically, even at a high frequency of f=3.6 GHz, a skin depth of approximately 1 μm is ensured. Therefore, if the thickness of the plating layer 20 is 1 μm or more, it is possible to secure a skin depth of about 1 μm for the electrical path through the lead frame even at a high frequency of 3.6 GHz. According to the study of the present inventors, if the skin depth can be secured to this extent, the high frequency loss can be suppressed to a sufficiently low level. Also, even if the frequency is higher, for example, if f is in the range of about 6.0 GHz or less, the skin depth t is not extremely small as shown in Table 1 above, so high frequency loss is reduced. It is thought that there are many cases in which it is possible to keep it within the permissible range.
　次にパワーモジュール９０１（図２）の製造方法について説明する。最初にパッケージ１０１（図４）が準備される。 Next, a method for manufacturing the power module 901 (Fig. 2) will be described. First a package 101 (FIG. 4) is prepared.
　続いて、ヒートシンク板５０の実装面ＲＭ（図４）上へパワー半導体素子２００（図２）が実装される。パワー半導体素子２００が実装される際は、熱硬化性樹脂と金属とを含有する接合層４２（図２）を介してヒートシンク板５０の実装面ＲＭとパワー半導体素子２００とが互いに接合されることが好ましい。言い換えれば、熱硬化性樹脂と金属とを含有するペースト状の接着剤の塗布と、その硬化とによる接合が行われることが好ましい。接合層４２の熱硬化性樹脂はエポキシ樹脂を含むことが好ましい。接合層４２の金属は銀を含むことが好ましい。 Then, the power semiconductor element 200 (FIG. 2) is mounted on the mounting surface RM (FIG. 4) of the heat sink plate 50. When the power semiconductor element 200 is mounted, the mounting surface RM of the heat sink plate 50 and the power semiconductor element 200 should be bonded to each other via the bonding layer 42 (FIG. 2) containing thermosetting resin and metal. is preferred. In other words, it is preferable to bond by applying a paste-like adhesive containing a thermosetting resin and a metal and curing the same. The thermosetting resin of the bonding layer 42 preferably contains an epoxy resin. The metal of the bonding layer 42 preferably contains silver.
　次に、パワー半導体素子２００とリードフレーム９１とがボンディングワイヤ２０５（図２）によって接続される。これにより、パワー半導体素子２００とリードフレーム９１との間の電気的接続が確保される。 Next, the power semiconductor element 200 and the lead frame 91 are connected by bonding wires 205 (FIG. 2). This ensures electrical connection between power semiconductor element 200 and lead frame 91 .
　次に、パッケージ１０１の追加枠体８２に蓋体３００を取り付けることによって、パワー半導体素子２００が封止される。これによりパワーモジュール９０１が得られる。具体的には、追加枠体８２と蓋体３００とが接着層４６によって互いに接着される。パッケージ１０１への蓋体３００の取り付けは、パワー半導体素子２００が実装されたパッケージ１０１に対して、リークの原因となるほどの熱ダメージを与えないように行われる。言い換えれば、パッケージ１０１への蓋体３００の取り付けは、ヒートシンク接着層４１、樹脂接着層６１および追加接着層６２に対して、リークの原因となるほどの熱ダメージを与えないように行われる。例えば、蓋体３００はパッケージ１０１へ、前述した熱ダメージにつながらない程度に低い硬化温度で硬化させられた接着層４６を介して取り付けられる。この硬化温度は、例えば２６０℃未満である。 Next, by attaching the lid 300 to the additional frame 82 of the package 101, the power semiconductor element 200 is sealed. A power module 901 is thus obtained. Specifically, the additional frame 82 and the lid 300 are adhered to each other by the adhesive layer 46 . The lid 300 is attached to the package 101 so that the package 101 in which the power semiconductor element 200 is mounted is not thermally damaged enough to cause leakage. In other words, the lid 300 is attached to the package 101 so that the heat sink adhesive layer 41, the resin adhesive layer 61, and the additional adhesive layer 62 are not thermally damaged enough to cause leakage. For example, the lid 300 is attached to the package 101 via the adhesive layer 46 cured at a low curing temperature that does not lead to the thermal damage described above. This curing temperature is, for example, less than 260°C.
　本実施の形態１によれば、第１に、高価な材料であるＡｕ、ＰｄおよびＡｇの少なくともいずれかからなる第２層２２の厚みである第２の厚みが１μｍ未満である。これにより、パッケージ１０１の製造コストを抑制することができる。第２に、第１層２１およびそれを直接的に覆う第２層２２が、リードフレーム９１の表面上において、厚み１μｍ以上の非磁性膜を構成する。これにより、リードフレーム９１を流れる高周波電流の、表皮効果に起因した電気的損失が、抑制される。以上から、パッケージ１０１の製造コストと、高周波損失とを、同時に抑制することができる。特に、第１厚みが０．５μｍ以上の場合、めっき層２０の厚みを確保しつつ第２厚みをより小さくすること（例えば、第２厚みを０．５μｍ以下にすること）ができるので、製造コストを、より低減することができる。 According to the first embodiment, firstly, the second thickness, which is the thickness of the second layer 22 made of at least one of Au, Pd and Ag, which are expensive materials, is less than 1 μm. Thereby, the manufacturing cost of the package 101 can be suppressed. Second, the first layer 21 and the second layer 22 directly covering it form a non-magnetic film having a thickness of 1 μm or more on the surface of the lead frame 91 . This suppresses the electrical loss of the high-frequency current flowing through the lead frame 91 due to the skin effect. As described above, the manufacturing cost of the package 101 and the high frequency loss can be suppressed at the same time. In particular, when the first thickness is 0.5 μm or more, it is possible to make the second thickness smaller (for example, to make the second thickness 0.5 μm or less) while ensuring the thickness of the plating layer 20. Costs can be further reduced.
　めっき層２０がヒートシンク板５０の実装面ＲＭを覆っている場合、実装面ＲＭを流れる高周波電流の、表皮効果に起因した電気的損失が抑制される。これにより、高周波損失を、より抑制することができる。ヒートシンク板５０の底面もめっき層２０によって覆われている場合、表皮効果に起因した電気的損失を、より抑制することができる。また、ヒートシンク板５０の露出面の全体がめっき層２０によって覆われている場合、表皮効果に起因した電気的損失を、より抑制することができる。 When the plating layer 20 covers the mounting surface RM of the heat sink plate 50, the electric loss due to the skin effect of the high-frequency current flowing through the mounting surface RM is suppressed. Thereby, the high frequency loss can be further suppressed. If the bottom surface of the heat sink plate 50 is also covered with the plating layer 20, electrical loss due to the skin effect can be further suppressed. Moreover, when the entire exposed surface of the heat sink plate 50 is covered with the plating layer 20, electrical loss due to the skin effect can be further suppressed.
　さらに、ヒートシンク板５０の表面上のめっき層２０は、上記のように表皮効果に起因した電気的損失を抑制するだけでなく、ヒートシンク板５０の表面の電気抵抗そのものを下げる効果が得られる場合がある。例えば、ヒートシンク板５０の表面がＮｉめっき処理されている場合、Ｎｉに比して、めっき層２０の材料の方が低い電気抵抗を有しているので、そのような効果が得られる。ヒートシンク板５０を通る電流経路の電気抵抗を下げることによって、パワーモジュール９０１（図２）の動作効率を高めることができる。また、ヒートシンク板５０を通る電流経路の電気抵抗が低ければ、量産されたパッケージ１０１間での当該電気抵抗のばらつきが問題となりにくくなる。これにより、量産されたパワーモジュール９０１間での特性ばらつきを抑えることができる。例えば、パワーモジュール９０１がパワーアンプである場合、製品間でのパワーアンプの出力ばらつきを抑えることができる。 Furthermore, the plated layer 20 on the surface of the heat sink plate 50 not only suppresses the electrical loss caused by the skin effect as described above, but also has the effect of lowering the electrical resistance itself on the surface of the heat sink plate 50 in some cases. be. For example, when the surface of the heat sink plate 50 is plated with Ni, the material of the plated layer 20 has a lower electrical resistance than Ni, so such an effect can be obtained. By reducing the electrical resistance of the current path through heat sink plate 50, the operating efficiency of power module 901 (FIG. 2) can be increased. In addition, if the electrical resistance of the current path passing through the heat sink plate 50 is low, variations in the electrical resistance among mass-produced packages 101 are less likely to become a problem. As a result, it is possible to suppress variations in characteristics among mass-produced power modules 901 . For example, when the power module 901 is a power amplifier, it is possible to suppress variations in power amplifier output between products.
　一般に、Ｎｉを用いためっき層の表面は、低い平滑性を有している。これに対して、めっき層２０はＮｉを用いていないので、めっき層２０の表面を平滑なものとしやすい。表面が平滑であれば、表面を流れる電流の経路が、より短くなる。これにより電気抵抗が低くなり、よって表皮効果の悪影響を緩和することができる。 In general, the surface of the plating layer using Ni has low smoothness. On the other hand, since the plating layer 20 does not use Ni, the surface of the plating layer 20 can be easily made smooth. The smoother the surface, the shorter the path for current flow across the surface. This results in a lower electrical resistance, thus mitigating the adverse effects of the skin effect.
　なお、前述したように、第２層２２は、第１層２１からの金属の原子拡散を有していてよい。例えば、第２層２２は、第１層２１としてのＣｕ層からのＣｕ原子拡散を有していてよい。これにより、第１層２１と第２層との間の密着強度が向上する。ただし、第１層２１の原子が第２層２２の表面まで拡散すると、第２層２２の表面が酸化されやすくなるので、ワイヤボンディング性や接合層４２の濡れ性が阻害される恐れがある。本発明者らの検討によれば、パッケージ１０１が過大な温度にまで加熱されなければ、少なくとも実用上十分な期間にわたって、この原子拡散を、第２層２２の機能を損なわない程度に抑えることができる。この観点で、パッケージ１０１へパワー半導体素子２００を実装する際に必要な熱処理温度は、なるべく低いことが好ましい。上記で具体的に説明した実装方法は、この目的に適している。 As described above, the second layer 22 may have metal atomic diffusion from the first layer 21 . For example, the second layer 22 may have Cu atomic diffusion from the Cu layer as the first layer 21 . This improves the adhesion strength between the first layer 21 and the second layer. However, when the atoms of the first layer 21 diffuse to the surface of the second layer 22, the surface of the second layer 22 is likely to be oxidized, which may impede the wire bondability and the wettability of the bonding layer 42. According to the studies of the present inventors, if the package 101 is not heated to an excessive temperature, this atomic diffusion can be suppressed to an extent that does not impair the function of the second layer 22 for at least a practically sufficient period. can. From this point of view, it is preferable that the heat treatment temperature required for mounting the power semiconductor element 200 on the package 101 is as low as possible. The implementation method specifically described above is suitable for this purpose.
　＜実施の形態２＞
　図７は、実施の形態２におけるパッケージ１０２の構成を概略的に示す断面図である。パッケージ１０１（図４：実施の形態１）と異なりパッケージ１０２は、枠体８１および追加枠体８２（図４）に代わって、枠体８０を有している。枠体８０の材料は、枠体８１と同様であってよい。リードフレーム９１は、樹脂接着層６１および追加接着層６２（図４）を用いずに、枠体８０に直接取り付けられている。この構成を得るためには、例えば、リードフレーム９１と枠体８０との一体成形が、射出成形法などにより行われる。 <Embodiment 2>
FIG. 7 is a cross-sectional view schematically showing the structure of package 102 according to the second embodiment. Unlike package 101 (FIG. 4: Embodiment 1), package 102 has frame 80 instead of frame 81 and additional frame 82 (FIG. 4). The material of frame 80 may be the same as that of frame 81 . The lead frame 91 is attached directly to the frame 80 without using the resin adhesive layer 61 and the additional adhesive layer 62 (FIG. 4). In order to obtain this configuration, for example, the lead frame 91 and the frame 80 are integrally molded by an injection molding method or the like.
　なお本実施の形態２の上記以外の構成については、上述した実施の形態１の構成とほぼ同じであるため、同一または対応する要素について同一の符号を付し、その説明を繰り返さない。パッケージ１０２は、パワーモジュール９０１（図２：実施の形態１）においてパッケージ１０１に代わって用いられてよい。 Since the configuration of the second embodiment other than the above is substantially the same as the configuration of the above-described first embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. Package 102 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
　＜実施の形態３＞
　図８は、実施の形態３におけるパワーモジュール９０３の構成を概略的に示す断面図である。パワーモジュール９０３は、パワーモジュール９０１（図２：実施の形態１）におけるパッケージ１０１がパッケージ１０３に置換された構造に対応している。 <Embodiment 3>
FIG. 8 is a cross-sectional view schematically showing the configuration of power module 903 according to the third embodiment. Power module 903 corresponds to a structure in which package 101 in power module 901 (FIG. 2: Embodiment 1) is replaced with package 103 .
　図９は、実施の形態３におけるパッケージ１０３の構成を概略的に示す断面図である。パッケージ１０３は、ヒートシンク板５０と、枠体８３と、リードフレーム９１と、めっき層２０とを有している。本実施の形態３においてはさらに、パッケージ１０３は接合層４０を有している。枠体８３は、接合層４０によって、リードフレーム９１およびヒートシンク板５０の各々に取り付けられている。枠体８３は、平面視（ＸＹ面における視野）においてヒートシンク板５０の実装面ＲＭを囲んでいる。 FIG. 9 is a cross-sectional view schematically showing the structure of the package 103 according to the third embodiment. The package 103 has a heat sink plate 50 , a frame 83 , a lead frame 91 and a plating layer 20 . In Embodiment 3, the package 103 further has a bonding layer 40 . Frame 83 is attached to each of lead frame 91 and heat sink plate 50 by bonding layer 40 . The frame body 83 surrounds the mounting surface RM of the heat sink plate 50 in plan view (field of view in the XY plane).
　めっき層２０は、リードフレーム９１の少なくとも一部を覆っている。めっき層２０は、図９に示されているようにリードフレーム９１の一部のみを覆っていてもよい。リードフレーム９１のうち少なくとも、平面視（ＸＹ面）における枠体８３から外側への突出部は、めっき層２０によって覆われていることが好ましい。本実施の形態３においては、リードフレーム９１の表面は、めっき層２０に覆われた部分と、めっき層２０には覆われずに接合層４０に接合された部分と、を有している。 The plating layer 20 covers at least part of the lead frame 91 . The plating layer 20 may cover only a portion of the leadframe 91 as shown in FIG. Preferably, at least portions of the lead frame 91 that protrude outward from the frame 83 in plan view (XY plane) are covered with the plating layer 20 . In Embodiment 3, the surface of lead frame 91 has a portion covered with plating layer 20 and a portion not covered with plating layer 20 but joined to bonding layer 40 .
　めっき層２０は、リードフレーム９１だけでなく、ヒートシンク板５０の一部、特に実装面ＲＭ、も覆っていてよい。この場合、リードフレーム９１のめっき処理と、ヒートシンク板５０のめっき処理とを、同時に行うことができる。 The plating layer 20 may cover not only the lead frame 91 but also a portion of the heat sink plate 50, especially the mounting surface RM. In this case, the plating of the lead frame 91 and the plating of the heat sink plate 50 can be performed simultaneously.
　図１０は、図９の領域Ｘの拡大図である。めっき層２０は、第１層２１と、第２層２２とを含む。第１層２１は、リードフレーム９１の少なくとも一部（本実施の形態においては一部のみ）を直接的に覆っている。なお、第１層２１および第２層２２の材料および厚みは、実施の形態１で説明されたものと同様である。 FIG. 10 is an enlarged view of region X in FIG. Plated layer 20 includes a first layer 21 and a second layer 22 . The first layer 21 directly covers at least part (only part in this embodiment) of the lead frame 91 . The material and thickness of the first layer 21 and the second layer 22 are the same as those described in the first embodiment.
　枠体８３は、絶縁枠体３１と、メタライズ膜３２と、めっき膜３３とを有している。絶縁枠体３１はセラミックスからなる。メタライズ膜３２は絶縁枠体３１の上面上および下面上に形成されている。めっき膜３３はメタライズ膜３２上に形成されている。一方のメタライズ膜３２は、めっき膜３３を介して接合層４０によってヒートシンク板５０に接合されており、他方のメタライズ膜３２は、めっき膜３３を介して接合層４０によってリードフレーム９１に接合されている。めっき膜３３は、例えば、Ｎｉめっき膜である。接合層４０は、例えば、ろう材である。 The frame 83 has an insulating frame 31 , a metallized film 32 and a plating film 33 . The insulating frame 31 is made of ceramics. A metallized film 32 is formed on the upper and lower surfaces of the insulating frame 31 . The plated film 33 is formed on the metallized film 32 . One metallized film 32 is bonded to the heat sink plate 50 by the bonding layer 40 via the plating film 33, and the other metallized film 32 is bonded to the lead frame 91 by the bonding layer 40 via the plating film 33. there is The plated film 33 is, for example, a Ni plated film. The bonding layer 40 is, for example, brazing material.
　次にパッケージ１０３の製造方法について説明する。まず、ヒートシンク板５０と、枠体８３と、リードフレーム９１とが準備される。ヒートシンク板５０は、例えば、板状の金属に対し切断加工や打ち抜き加工をすることで形成され得る。次に、これら部材が接合層４０によって互いに接合される。次に、めっき層２０として、第１層２１および第２層２２が順に形成される。これによりパッケージ１０３が得られる。 Next, a method for manufacturing the package 103 will be described. First, the heat sink plate 50, the frame 83, and the lead frame 91 are prepared. The heat sink plate 50 can be formed, for example, by cutting or punching a metal plate. These members are then bonded together by a bonding layer 40 . Next, as the plated layer 20, the first layer 21 and the second layer 22 are formed in order. A package 103 is thus obtained.
　なお本実施の形態３の上記以外の構成については、上述した実施の形態１の構成とほぼ同じであるため、同一または対応する要素について同一の符号を付し、その説明を繰り返さない。 Since the configuration of the third embodiment other than the above is substantially the same as the configuration of the first embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated.
　＜実施の形態４＞
　図１１は、実施の形態４におけるパッケージ１０４の構成を概略的に示す断面図である。パッケージ１０４は、パッケージ１０１（図４：実施の形態１）におけるリードフレーム９１およびめっき層２０のそれぞれに代わって、リードフレーム９４およびめっき層２４を有している。リードフレーム９４およびめっき層２４のそれぞれの配置は、リードフレーム９１およびめっき層２０と同様である。よって、めっき層２４は、リードフレーム９４の少なくとも一部（本実施の形態においては全部）を直接的に覆っている。また、めっき層２４は、リードフレーム９４だけでなく、ヒートシンク板５０の少なくとも一部、特に実装面ＲＭ、も覆っていてよい。さらに、図１１に示されているように、ヒートシンク板５０は実装面ＲＭと反対の底面を有しており、当該底面がめっき層２４によって覆われていてよい。ヒートシンク板５０の表面は、枠体（本実施の形態においては枠体８１）に面する部分と、他の部分（以下、「露出面」とも称する）と、からなる。図１１においては、ヒートシンク板５０の表面のうち、ヒートシンク接着層４１に覆われた部分以外のすべての部分が露出面に対応している。この露出面の全体がめっき層２４によって覆われていてよい。また、めっき層２４は、図１１に示されているように、ヒートシンク板５０の全部を覆っていてもよい。 <Embodiment 4>
FIG. 11 is a cross-sectional view schematically showing the configuration of package 104 according to the fourth embodiment. Package 104 has lead frame 94 and plating layer 24 in place of lead frame 91 and plating layer 20 in package 101 (FIG. 4: Embodiment 1), respectively. The respective arrangements of lead frame 94 and plating layer 24 are similar to lead frame 91 and plating layer 20 . Therefore, the plating layer 24 directly covers at least a portion (entirely in this embodiment) of the lead frame 94 . Moreover, the plating layer 24 may cover not only the lead frame 94 but also at least a portion of the heat sink plate 50, especially the mounting surface RM. Furthermore, as shown in FIG. 11 , the heat sink plate 50 has a bottom surface opposite to the mounting surface RM, and the bottom surface may be covered with the plating layer 24 . The surface of the heat sink plate 50 consists of a portion facing the frame (frame 81 in this embodiment) and other portions (hereinafter also referred to as "exposed surface"). In FIG. 11, the entire surface of the heatsink plate 50 except for the portion covered with the heatsink adhesive layer 41 corresponds to the exposed surface. The entire exposed surface may be covered with the plating layer 24 . Alternatively, the plating layer 24 may cover the entire heat sink plate 50 as shown in FIG.
　リードフレーム９４は、非磁性体からなる。この磁性体は、銅を含むことが好ましく、例えばＣｕまたはＣｕ合金である。Ｃｕ合金は、９０ｗｔ％以上で銅を含有していることが好ましい。 The lead frame 94 is made of non-magnetic material. This magnetic body preferably contains copper, for example Cu or a Cu alloy. The Cu alloy preferably contains 90 wt% or more of copper.
　めっき層２４は、Ａｕ、ＰｄおよびＡｇの少なくともいずれかからなる。これにより、酸化や硫化などによる変質を抑制できる。酸化だけでなく硫化の抑制も重要な場合は、めっき層２４は、好ましくは、ＡｕおよびＰｄの少なくともいずれかからなる。一方、材料コストの観点では、めっき層２４は、好ましくは少なくとも部分的にＡｇからなり、より好ましくは全体的にＡｇからなる。めっき層２４は、リードフレーム９４からのＣｕ原子拡散を有していてよい。またリードフレーム９４は、めっき層２４からの原子拡散を有していてよい。めっき層２４は積層膜であってよい。具体的には、めっき層２４は、下地層としてのＰｄ膜と、このＰｄ膜を直接的に覆うＡｕ膜とによって構成されていてよい。めっき層２４の厚みは１μｍ未満である。まためっき層２４の厚みは０．０１μｍ以上であることが好ましい。めっき層２４の厚みがこの程度であれば、めっき層２４の表面が酸化してワイヤボンディング性や接合層４２の濡れ性が阻害されることを防止できる。 The plating layer 24 is made of at least one of Au, Pd and Ag. As a result, deterioration due to oxidation, sulfurization, or the like can be suppressed. If suppression of sulfidation as well as oxidation is important, the plating layer 24 is preferably made of at least one of Au and Pd. On the other hand, in terms of material cost, the plating layer 24 preferably consists of Ag at least partially, and more preferably consists entirely of Ag. The plating layer 24 may have Cu atomic diffusion from the leadframe 94 . Leadframe 94 may also have atomic diffusion from plating layer 24 . The plating layer 24 may be a laminated film. Specifically, the plating layer 24 may be composed of a Pd film as a base layer and an Au film directly covering the Pd film. The thickness of the plating layer 24 is less than 1 μm. Moreover, the thickness of the plating layer 24 is preferably 0.01 μm or more. If the thickness of the plating layer 24 is about this level, it is possible to prevent the surface of the plating layer 24 from being oxidized and impairing the wire bonding properties and the wettability of the bonding layer 42 .
　なお本実施の形態４の上記以外の構成については、上述した実施の形態１の構成とほぼ同じであるため、同一または対応する要素について同一の符号を付し、その説明を繰り返さない。パッケージ１０４は、パワーモジュール９０１（図２：実施の形態１）においてパッケージ１０１に代わって用いられてよい。 Since the configuration of the fourth embodiment other than the above is substantially the same as the configuration of the first embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. Package 104 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
　本実施の形態４によれば、第１に、高価な材料であるＡｕ、ＰｄおよびＡｇの少なくともいずれかからなるめっき層２４の厚みが１μｍ未満である。これにより、パッケージ１０４の製造コストを抑制することができる。第２に、めっき層２４と、非磁性体からなるリードフレーム９４の、めっき層２４によって覆われた部分と、によって、リードフレーム９４の表面に沿って、十分な厚みを有する非磁性導体領域が確保される。これにより、リードフレーム９４を流れる高周波電流の、表皮効果に起因した電気的損失が、抑制される。以上から、パッケージ１０４の製造コストと、高周波損失とを、同時に抑制することができる。 According to the fourth embodiment, firstly, the thickness of the plating layer 24 made of at least one of Au, Pd and Ag, which are expensive materials, is less than 1 μm. Thereby, the manufacturing cost of the package 104 can be suppressed. Second, the plating layer 24 and the portion of the lead frame 94 made of a non-magnetic material covered with the plating layer 24 form a non-magnetic conductor region having a sufficient thickness along the surface of the lead frame 94 . Secured. This suppresses the electrical loss of the high-frequency current flowing through the lead frame 94 due to the skin effect. As described above, the manufacturing cost of the package 104 and the high frequency loss can be suppressed at the same time.
　めっき層２４がヒートシンク板５０の実装面ＲＭを覆っている場合、実装面ＲＭを流れる高周波電流の、表皮効果に起因した電気的損失が抑制される。これにより、高周波損失を、より抑制することができる。ヒートシンク板５０の底面もめっき層２４によって覆われている場合、表皮効果に起因した電気的損失を、より抑制することができる。また、ヒートシンク板５０の露出面の全体がめっき層２４によって覆われている場合、表皮効果に起因した電気的損失を、より抑制することができる。 When the plating layer 24 covers the mounting surface RM of the heat sink plate 50, electrical loss due to the skin effect of the high-frequency current flowing through the mounting surface RM is suppressed. Thereby, the high frequency loss can be further suppressed. If the bottom surface of the heat sink plate 50 is also covered with the plating layer 24, electrical loss due to the skin effect can be further suppressed. Moreover, when the entire exposed surface of the heat sink plate 50 is covered with the plating layer 24, electrical loss due to the skin effect can be further suppressed.
　さらに、ヒートシンク板５０の表面上のめっき層２４は、上記のように表皮効果に起因した電気的損失を抑制するだけでなく、ヒートシンク板５０の表面の電気抵抗そのものを下げる効果が得られる場合がある。例えば、ヒートシンク板５０の表面がＮｉめっき処理されている場合、Ｎｉに比して、めっき層２４の材料の方が低い電気抵抗を有しているので、そのような効果が得られる。ヒートシンク板５０を通る電流経路の電気抵抗を下げることによって、パワーモジュールの動作効率を高めることができる。また、ヒートシンク板５０を通る電流経路の電気抵抗が低ければ、量産されたパッケージ１０４間での当該電気抵抗のばらつきが問題となりにくくなる。これにより、量産されたパワーモジュール間での特性ばらつきを抑えることができる。例えば、パワーモジュールがパワーアンプである場合、製品間でのパワーアンプの出力ばらつきを抑えることができる。 Furthermore, the plated layer 24 on the surface of the heat sink plate 50 not only suppresses electrical loss caused by the skin effect as described above, but also has the effect of lowering the electrical resistance itself on the surface of the heat sink plate 50 in some cases. be. For example, when the surface of the heat sink plate 50 is plated with Ni, the material of the plated layer 24 has lower electrical resistance than Ni, so such an effect can be obtained. By reducing the electrical resistance of the current path through the heat sink plate 50, the operating efficiency of the power module can be increased. In addition, if the electrical resistance of the current path passing through the heat sink plate 50 is low, variations in the electrical resistance among mass-produced packages 104 are less likely to become a problem. As a result, it is possible to suppress variations in characteristics among mass-produced power modules. For example, when the power module is a power amplifier, it is possible to suppress variations in power amplifier output between products.
　一般に、Ｎｉを用いためっき層の表面は、低い平滑性を有している。これに対して、めっき層２０はＮｉを用いていないので、めっき層２０の表面を平滑なものとしやすい。表面が平滑であれば、表面を流れる電流の経路が、より短くなる。これにより電気抵抗が低くなり、よって表皮効果の悪影響を緩和することができる。 In general, the surface of the plating layer using Ni has low smoothness. On the other hand, since the plating layer 20 does not use Ni, the surface of the plating layer 20 can be easily made smooth. The smoother the surface, the shorter the path for current flow across the surface. This results in a lower electrical resistance, thus mitigating the adverse effects of the skin effect.
　なお、仮に、めっき層２４の下地層としてニッケルめっきを設けたとすると、ニッケルめっきの領域で表皮効果に起因する電気的損失が生じてしまい、非磁性体からなるリードフレーム９４が上記の非磁性導体領域として寄与しにくくなる。 If nickel plating were provided as an underlying layer of the plating layer 24, electrical loss would occur in the nickel plating region due to the skin effect, and the lead frame 94 made of a non-magnetic material would become the above-mentioned non-magnetic conductor. It becomes difficult to contribute as an area.
　なお、前述したように、めっき層２４は、リードフレーム９４からのＣｕ原子拡散を有していてよい。これにより、めっき層２４とリードフレーム９４との間の密着強度が向上する。ただし、Ｃｕ原子がめっき層２４の表面まで拡散すると、めっき層２４の表面が酸化されやすくなるので、ワイヤボンディング性や接合層４２の濡れ性が阻害される恐れがある。本発明者らの検討によれば、パッケージ１０４が過大な温度にまで加熱されなければ、少なくとも実用上十分な期間にわたって、この原子拡散を、めっき層２４の機能を損なわない程度に抑えることができる。この観点で、パッケージ１０４へパワー半導体素子２００を実装する際に必要な熱処理温度は、なるべく低いことが好ましい。実施の形態１で具体的に説明した実装方法は、この目的に適している。 In addition, as described above, the plating layer 24 may have Cu atoms diffused from the lead frame 94 . This improves the adhesion strength between the plating layer 24 and the lead frame 94 . However, when Cu atoms diffuse to the surface of the plating layer 24, the surface of the plating layer 24 is likely to be oxidized, which may hinder the wire bonding properties and the wettability of the bonding layer 42. According to the studies of the present inventors, if the package 104 is not heated to an excessive temperature, this atomic diffusion can be suppressed to the extent that the function of the plating layer 24 is not impaired at least for a practically sufficient period of time. . From this point of view, it is preferable that the heat treatment temperature required for mounting the power semiconductor element 200 on the package 104 is as low as possible. The mounting method specifically described in Embodiment 1 is suitable for this purpose.
　＜実施の形態５＞
　図１２は、実施の形態５におけるパッケージ１０５の構成を概略的に示す断面図である。パッケージ１０４（図１１：実施の形態１）と異なりパッケージ１０５は、枠体８１および追加枠体８２（図４）に代わって、枠体８０を有している。枠体８０の材料は、枠体８１と同様であってよい。リードフレーム９４は、樹脂接着層６１および追加接着層６２（図１１）を用いずに、枠体８０に直接取り付けられている。この構成を得るためには、例えば、リードフレーム９４と枠体８０との一体成形が、射出成形法などにより行われる。 <Embodiment 5>
FIG. 12 is a cross-sectional view schematically showing the structure of package 105 according to the fifth embodiment. Unlike package 104 (FIG. 11: Embodiment 1), package 105 has frame 80 instead of frame 81 and additional frame 82 (FIG. 4). The material of frame 80 may be the same as that of frame 81 . The lead frame 94 is attached directly to the frame 80 without using the resin adhesive layer 61 and the additional adhesive layer 62 (FIG. 11). In order to obtain this configuration, for example, the lead frame 94 and the frame 80 are integrally molded by an injection molding method or the like.
　なお本実施の形態５の上記以外の構成については、上述した実施の形態４の構成とほぼ同じであるため、同一または対応する要素について同一の符号を付し、その説明を繰り返さない。パッケージ１０５は、パワーモジュール９０１（図２：実施の形態１）においてパッケージ１０１に代わって用いられてよい。 Since the configuration of the fifth embodiment other than the above is substantially the same as the configuration of the fourth embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. Package 105 may be used instead of package 101 in power module 901 (FIG. 2: Embodiment 1).
　＜実施の形態６＞
　図１３は、実施の形態６におけるパッケージ１０６の構成を概略的に示す断面図である。パッケージ１０６は、パッケージ１０３（図９：実施の形態３）におけるリードフレーム９１およびめっき層２０のそれぞれが、リードフレーム９４およびめっき層２４に置換された構造に対応している。なお本実施の形態６の上記以外の構成については、上述した実施の形態３または４の構成とほぼ同じであるため、同一または対応する要素について同一の符号を付し、その説明を繰り返さない。パッケージ１０６は、パワーモジュール９０３（図８：実施の形態３）においてパッケージ１０３に代わって用いられてよい。 <Embodiment 6>
FIG. 13 is a cross-sectional view schematically showing the configuration of package 106 according to the sixth embodiment. Package 106 corresponds to a structure in which lead frame 91 and plating layer 20 in package 103 (FIG. 9: Embodiment 3) are replaced with lead frame 94 and plating layer 24, respectively. Since the configuration of the sixth embodiment other than the above is substantially the same as the configuration of the above-described third or fourth embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. Package 106 may be used instead of package 103 in power module 903 (FIG. 8: Embodiment 3).
　＜実施の形態７＞
　本実施の形態７においては、実施の形態１～３で説明されたパッケージ１０１～１０３のいずれかにおいて、第１層２１および第２層２２を含むめっき層２０に代わって、Ａｇからなるめっき層（以下、「Ａｇめっき層」とも称する）が用いられる。Ａｇめっき層は、第１層２１（実施の形態１～３）と同様に、リードフレーム９１の少なくとも一部を直接的に覆っている。またＡｇめっき層は、第２層２２（実施の形態１～３）と同様に、露出された表面を有している。またＡｇめっき層の厚みは、第１層２１および第２層２２の総厚みと同様に、１μｍ以上である。言い換えれば、本実施の形態７は、実施の形態１～３において、第１層２１および第２層２２の両方がＡｇからなる場合に相当する。本実施の形態７によれば、実施の形態１～３と異なり第１層２１および第２層２２の材料を個別に最適化することができない短所はあるものの、めっき層の構成を単純化することができる。 <Embodiment 7>
In the seventh embodiment, instead of the plating layer 20 including the first layer 21 and the second layer 22 in any of the packages 101 to 103 described in the first to third embodiments, a plating layer made of Ag (hereinafter also referred to as "Ag plating layer") is used. The Ag plating layer directly covers at least a portion of lead frame 91, like first layer 21 (embodiments 1 to 3). Also, the Ag plating layer has an exposed surface, like the second layer 22 (Embodiments 1 to 3). Also, the thickness of the Ag plating layer is 1 μm or more, like the total thickness of the first layer 21 and the second layer 22 . In other words, the seventh embodiment corresponds to the case where both the first layer 21 and the second layer 22 are made of Ag in the first to third embodiments. According to the seventh embodiment, unlike the first to third embodiments, although there is a disadvantage that the materials of the first layer 21 and the second layer 22 cannot be individually optimized, the configuration of the plating layer is simplified. be able to.
　上述した実施の形態は、矛盾のない範囲で互いに自由に組み合わされてよい。この発明は詳細に説明されたが、上記した説明は、すべての態様において、例示であって、この発明がそれに限定されるものではない。例示されていない無数の変形例が、この発明の範囲から外れることなく想定され得るものと解される。 The above-described embodiments may be freely combined with each other within a consistent range. Although the present invention has been described in detail, the above description is, in all its aspects, exemplary, and the invention is not limited thereto. It is understood that numerous variations not illustrated can be envisioned without departing from the scope of the invention.
　２０，２４　　　：めっき層
　２１　　　　　　：第１層
　２２　　　　　　：第２層
　５０　　　　　　：ヒートシンク板
　８０，８１，８３：枠体
　９１，９４　　　：リードフレーム
　１０１～１０６　：パッケージ
　２００　　　　　：パワー半導体素子（電子部品）
　３００　　　　　：蓋体
　９０１，９０３　：パワーモジュール
　ＲＭ　　　　　　：実装面 20, 24: plating layer 21: first layer 22: second layer 50: heat sink plate 80, 81, 83: frame 91, 94: lead frame 101 to 106: package 200: power semiconductor element (electronic component)
300: Lid 901, 903: Power module RM: Mounting surface

Claims (16)

  1. 　電子部品が実装されることになる実装面を有するヒートシンク板と、
    　前記ヒートシンク板に取り付けられ、前記ヒートシンク板の前記実装面を囲む枠体と、
    　前記枠体に取り付けられ、磁性体からなるリードフレームと、
    　前記リードフレームの少なくとも一部を覆うめっき層と、
    を備え、
    　前記めっき層は、
    　　前記リードフレームの前記少なくとも一部を直接的に覆い、非磁性体からなり、金およびパラジウムのいずれとも異なる金属からなり、第１厚みを有する第１層と、
    　　前記第１層を直接的に覆い、金、パラジウムおよび銀の少なくともいずれかからなり、第２厚みを有する第２層と、
    を含み、前記第１厚みと前記第２厚みとの合計が１μｍ以上であり、前記第２厚みが１μｍ未満である、パッケージ。     a heat sink plate having a mounting surface on which electronic components are to be mounted;
    a frame attached to the heat sink plate and surrounding the mounting surface of the heat sink plate;
    a lead frame attached to the frame and made of a magnetic material;
    a plating layer covering at least a portion of the lead frame;
    with
    The plating layer is
    a first layer that directly covers the at least part of the lead frame, is made of a non-magnetic material, is made of a metal other than gold and palladium, and has a first thickness;
    a second layer directly overlying the first layer and made of at least one of gold, palladium and silver and having a second thickness;
    wherein the sum of said first thickness and said second thickness is greater than or equal to 1 μm and said second thickness is less than 1 μm.
  2. 　請求項１に記載のパッケージであって、
    　前記金属は、銅および銀の少なくともいずれかを含む、パッケージ。     A package according to claim 1, comprising:
    The package, wherein the metal includes at least one of copper and silver.
  3. 　請求項１または２に記載のパッケージであって、
    　前記第１厚みが０．５μｍ以上である、パッケージ。     A package according to claim 1 or 2,
    A package, wherein the first thickness is 0.5 μm or more.
  4. 　請求項１または２に記載のパッケージであって、
    　前記めっき層は前記ヒートシンク板の前記実装面を覆っている、パッケージ。     A package according to claim 1 or 2,
    The package, wherein the plating layer covers the mounting surface of the heat sink plate.
  5. 　請求項４に記載のパッケージであって、
    　前記ヒートシンク板は前記実装面と反対の底面を有しており、前記底面が前記めっき層によって覆われている、パッケージ。     A package according to claim 4, comprising:
    The package, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
  6. 　請求項４に記載のパッケージであって、
    　前記ヒートシンク板の表面は、前記枠体に面する部分と、他の部分とからなり、前記他の部分の全体が前記めっき層によって覆われている、パッケージ。     A package according to claim 4, comprising:
    The package, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer.
  7. 　請求項１または２に記載のパッケージと、
    　前記ヒートシンク板の前記実装面上に実装された前記電子部品と、
    　前記電子部品を封止するように前記パッケージに取り付けられた蓋体と、
    を備え、
    　前記電子部品は３．６ＧＨｚ以上の動作周波数を有している、パワーモジュール。     a package according to claim 1 or 2;
    the electronic component mounted on the mounting surface of the heat sink plate;
    a lid attached to the package to seal the electronic component;
    with
    The power module, wherein the electronic component has an operating frequency of 3.6 GHz or higher.
  8. 　請求項７に記載のパワーモジュールであって、
    　前記パッケージの前記第２層は、前記第１層からの前記金属の原子拡散を有している、パワーモジュール。     A power module according to claim 7,
    A power module, wherein the second layer of the package has an atomic diffusion of the metal from the first layer.
  9. 　電子部品が実装されることになる実装面を有するヒートシンク板と、
    　前記ヒートシンク板に取り付けられ、前記ヒートシンク板の前記実装面を囲む枠体と、
    　前記枠体に取り付けられ、非磁性体からなるリードフレームと、
    　前記リードフレームの少なくとも一部を直接的に覆い、金、パラジウムおよび銀の少なくともいずれかからなり、１μｍ未満の厚みを有するめっき層と、
    を備える、パッケージ。     a heat sink plate having a mounting surface on which electronic components are to be mounted;
    a frame attached to the heat sink plate and surrounding the mounting surface of the heat sink plate;
    a lead frame attached to the frame and made of a non-magnetic material;
    a plating layer that directly covers at least a portion of the lead frame, is made of at least one of gold, palladium, and silver and has a thickness of less than 1 μm;
    package.
  10. 　請求項９に記載のパッケージであって、
    　前記リードフレームは銅または銅合金からなる、パッケージ。     A package according to claim 9, comprising:
    The package, wherein the lead frame is made of copper or a copper alloy.
  11. 　請求項９または１０に記載のパッケージであって、
    　前記めっき層は前記ヒートシンク板の前記実装面を覆っている、パッケージ。     A package according to claim 9 or 10,
    The package, wherein the plating layer covers the mounting surface of the heat sink plate.
  12. 　請求項１１に記載のパッケージであって、
    　前記ヒートシンク板は前記実装面と反対の底面を有しており、前記底面が前記めっき層によって覆われている、パッケージ。     12. The package of claim 11, comprising:
    The package, wherein the heat sink plate has a bottom surface opposite to the mounting surface, and the bottom surface is covered with the plating layer.
  13. 　請求項１１に記載のパッケージであって、
    　前記ヒートシンク板の表面は、前記枠体に面する部分と、他の部分とからなり、前記他の部分の全体が前記めっき層によって覆われている、パッケージ。     12. The package of claim 11, comprising:
    The package, wherein the surface of the heat sink plate comprises a portion facing the frame and another portion, and the other portion is entirely covered with the plating layer.
  14. 　請求項９または１０に記載のパッケージと、
    　前記ヒートシンク板の前記実装面上に実装された前記電子部品と、
    　前記電子部品を封止するように前記パッケージに取り付けられた蓋体と、
    を備え、
    　前記電子部品は３．６ＧＨｚ以上の動作周波数を有している、パワーモジュール。     a package according to claim 9 or 10;
    the electronic component mounted on the mounting surface of the heat sink plate;
    a lid attached to the package to seal the electronic component;
    with
    The power module, wherein the electronic component has an operating frequency of 3.6 GHz or higher.
  15. 　請求項１４に記載のパワーモジュールであって、
    　前記パッケージの前記めっき層は、前記リードフレームからの銅原子拡散を有している、パワーモジュール。     A power module according to claim 14,
    A power module, wherein the plating layer of the package has copper atomic diffusion from the lead frame.
  16. 　電子部品が実装されることになる実装面を有するヒートシンク板と、
    　前記ヒートシンク板に取り付けられ、前記ヒートシンク板の前記実装面を囲む枠体と、
    　前記枠体に取り付けられ、磁性体からなるリードフレームと、
    　前記リードフレームの少なくとも一部を直接的に覆い、銀からなり、１μｍ以上の厚みを有し、露出された表面を有するめっき層と、
    を備える、パッケージ。     a heat sink plate having a mounting surface on which electronic components are to be mounted;
    a frame attached to the heat sink plate and surrounding the mounting surface of the heat sink plate;
    a lead frame attached to the frame and made of a magnetic material;
    a plating layer that directly covers at least a portion of the lead frame, is made of silver, has a thickness of 1 μm or more, and has an exposed surface;
    package.
PCT/JP2022/028038 2021-07-26 2022-07-19 Package and power module WO2023008252A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11111909A (en) * 1997-10-07 1999-04-23 Seiichi Serizawa Lead frame for semiconductor device
JP2006222471A (en) * 2006-05-29 2006-08-24 Matsushita Electric Ind Co Ltd Resin-sealed semiconductor device
JP2020155699A (en) * 2019-03-22 2020-09-24 日本碍子株式会社 Manufacturing method for package and power semiconductor module

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11111909A (en) * 1997-10-07 1999-04-23 Seiichi Serizawa Lead frame for semiconductor device
JP2006222471A (en) * 2006-05-29 2006-08-24 Matsushita Electric Ind Co Ltd Resin-sealed semiconductor device
JP2020155699A (en) * 2019-03-22 2020-09-24 日本碍子株式会社 Manufacturing method for package and power semiconductor module

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