WO2020136979A1 - Joint à brasure tendre - Google Patents

Joint à brasure tendre Download PDF

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Publication number
WO2020136979A1
WO2020136979A1 PCT/JP2019/031255 JP2019031255W WO2020136979A1 WO 2020136979 A1 WO2020136979 A1 WO 2020136979A1 JP 2019031255 W JP2019031255 W JP 2019031255W WO 2020136979 A1 WO2020136979 A1 WO 2020136979A1
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layer
alloy layer
content
boundary
mol
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PCT/JP2019/031255
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English (en)
Japanese (ja)
Inventor
英治 日野
広信 澤渡
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Ｊｘ金属株式会社
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Priority to JP2020502503A priority Critical patent/JPWO2020136979A1/ja
Priority to CN201980003606.1A priority patent/CN111630646A/zh
Publication of WO2020136979A1 publication Critical patent/WO2020136979A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C12/00—Alloys based on antimony or bismuth

Definitions

  • the present invention relates to solder joints.
  • solder alloys Due to environmental considerations, the use of lead-free solder alloys is recommended.
  • the temperature range of the solder alloy suitable for use as solder changes depending on the composition thereof.
  • Power devices are used in a wide range of fields such as hybrid vehicles and power transmission and transformation as elements for power conversion.
  • Si chip devices could be used, but in fields where high breakdown voltage, large current applications, and high speed operation are required, SiC, GaN, etc., which have a larger bandgap than Si, have been receiving attention in recent years.
  • the operating temperature of conventional power modules was up to 170°C, but next-generation SiC, GaN, etc. may reach temperatures of 200°C or higher. Along with this, heat resistance and heat dissipation are required for each material used for a module mounting these chips.
  • Sn-3.0Ag-0.5Cu solder (Ag: 3.0% by mass, Cu: 0.5% by mass, balance Sn) is used as the joint having such characteristics.
  • a joint is preferred.
  • heat resistance is required to be higher than that of a joint made of Sn-3.0Ag-0.5Cu solder having a melting point of around 220°C.
  • a joint portion made of Pb solder Pb-5Sn, which is not preferable from the viewpoint of environmental regulations, can handle the operating temperature of the next-generation type module.
  • Pb-5Sn solder has a sufficient function as a bonding material for next-generation power modules, it is lead-containing and should not be used from the viewpoint of future environmental regulations. Further, the Ag fine powder paste can give sufficient bonding strength and heat resistance to the bonding portion depending on the conditions, but it has a problem of material cost.
  • an object of the present invention is to provide a solder joint having excellent durability in a high temperature range.
  • the present invention includes the following (1).
  • (1) It is a joint part where the UBM and the solder alloy are joined, and in order from the UBM side, Ni layer continuous from the UBM side, NiSn alloy layer, (Cu, Ni, Pd) ⁇ Sn alloy layer, A BiSn alloy layer, A joint comprising a Bi layer continuous to the solder alloy side.
  • solder joint having excellent durability in a high temperature range can be obtained.
  • FIG. 1 is an EPMA composite map image after the reflow process of the joint portion of the first embodiment.
  • FIG. 2 is an EPMA composite map image after holding for 1000 hours at a temperature of 250° C. after the reflow treatment of the joint portion in Example 1.
  • FIG. 3 is an EPMA composite map image after the reflow process of the joint portion of Comparative Example 1.
  • FIG. 4 is an EPMA composite map image after holding for 1000 hours at a temperature of 250° C. after the reflow treatment of the joint portion of Comparative Example 1.
  • FIG. 5 is an STM image after the reflow processing of the joint portion in Example 1.
  • FIG. 6 is a graph in which the vertical axis represents the concentration (mol %) of atoms obtained by analysis along the analysis line (55) in FIG.
  • FIG. 7 is an STM image after the reflow process of the joint portion of Comparative Example 1.
  • FIG. 8 is a graph in which the vertical axis represents the concentration (mol %) of atoms obtained by analysis along the analysis line (75) in FIG. 7 and the horizontal axis represents the distance from the analysis starting point of the analysis line. is there.
  • the joint portion according to the present invention is a joint portion in which a UBM and a solder alloy are joined, and in order from the UBM side, a Ni layer continuous from the UBM side, a NiSn alloy layer, and a (Cu, Ni, Pd) ⁇ Sn alloy layer. , BiSn alloy layer and a Bi layer continuous to the solder alloy side.
  • the UBM (Under Bump Metal) is a metal layer that is interposed to form a solder bump on an electrode (for example, an Al electrode) on a chip (for example, a Si chip).
  • a Ni layer or a Ni alloy layer is usually formed, and a Pd layer and/or an Au layer or the like is formed thereon.
  • the UBM includes, for example, a Ni layer formed on an Al electrode on a Si chip, a Pd layer formed thereon, and an Au layer formed thereon.
  • the metal layer can be mentioned.
  • solder alloy may be a lead-free solder alloy, for example, the Bi—Cu—Sn alloy having the composition disclosed in the examples.
  • the joint portion of the present invention is a joint portion in which the UBM and the solder alloy are joined, the UBM loses the constitution of the original metal layer due to the joining, and only the Ni layer, which was the main layer of the UBM, can be detected. Remains as.
  • the Ni layer derived from this UBM is continuous all the way to the joint, and in the vicinity of the joint, the Ni layer is continuous from the UBM side.
  • the UBM side the side on which the UBM existed on both sides of the joining is referred to as the UBM side in this specification.
  • a Ni layer continuous from the UBM side may be simply referred to as a Ni layer.
  • This Ni layer is a layer continuous from the UBM side, but in order to clarify the structure of the joint, it is described as one of the layers constituting the joint in this specification.
  • solder alloy side of joint Since the joint portion of the present invention is a joint portion in which the UBM and the solder alloy are joined, the solder alloy side of the joint portion is continuous with the solder alloy.
  • the solder alloy is an alloy whose main component is Bi, and the solder alloy side of the joint is a Bi layer continuous to the solder alloy side.
  • the solder alloy has a phase different from that of the original solder alloy due to the joining, and of both sides of the joining, the side where this solder alloy exists is referred to as the solder alloy side in this specification.
  • the Bi layer continuous to the solder alloy side may be simply referred to as a Bi layer.
  • the Bi layer is a layer continuous to the solder alloy side, but is described as one of the layers forming the joint in this specification in order to clarify the constitution of the joint.
  • the NiSn alloy layer contains Ni, Sn, and P.
  • the Ni content at the boundary with the Ni layer is larger than the Ni content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer.
  • the Sn content at the boundary with the Ni layer is smaller than the Sn content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer.
  • the Sn content at the boundary with the Ni layer is 0.4 mol% or less, preferably 0.35 mol% or less.
  • the P content at the boundary with the Ni layer is larger than the P content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer.
  • the P content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is 0.5 mol% or less, preferably 0.3 mol% or less.
  • the Ni content at each distance from the boundary with the Ni layer is in the range of 21 mol% to 83 mol%, preferably in the range of 22 mol% to 80 mol%. That the Ni content at each distance from the boundary with the Ni layer is within the above range means that one or more measurement points are provided according to the distance from the boundary with the Ni layer, and the Ni content at each measurement point. It means that all of them are within the above range or can be estimated as such. Being able to make such an estimation means being able to make such an estimation, for example, by extrapolation from measurement values at adjacent measurement points.
  • the number of measurement points is not particularly limited, but from the viewpoint of practical measurement operation, for example, about 1 to 20 or about 1 to 5 measurement points can be provided. In the following description, the description “at each distance” is used in the same meaning as described above.
  • the Sn content at each distance from the boundary with the Ni layer is in the range of 0.2 mol% to 48 mol%, preferably 0.25 mol% to 45 mol%. In range. That the Sn content at each distance from the boundary with the Ni layer is within the above range has the same meaning as described above for the Ni content.
  • the P content at each distance from the boundary with the Ni layer is in the range of 0.1 mol% to 10 mol%, preferably 0.2 mol% to 9 mol%. In range. That the P content at each distance from the boundary with the Ni layer is in the above range has the same meaning as described above for the Ni content.
  • the Bi content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is 2 mol% or less, preferably 1 mol% or less.
  • the Bi content at each distance from the boundary with the Ni layer is in the range of 0.2 mol% to 2 mol%, preferably 0.3 mol% to 1.5 mol%. It is in the range of mol %. That the Bi content at each distance from the boundary with the Ni layer is within the above range has the same meaning as described above for the Ni content.
  • the NiSn alloy layer has a significantly reduced Bi content, that is, Bi intrusion is efficiently prevented.
  • the NiSn alloy layer has a thickness of, for example, 0.03 to 0.1 [ ⁇ m], preferably 0.04 to 0.1 [ ⁇ m], and preferably 0.05 to 0.1 [. ⁇ m], preferably in the range of 0.06 to 0.1 [ ⁇ m].
  • the Cu content at the boundary with the Ni layer is smaller than the Cu content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer.
  • the Cu content at the boundary with the Ni layer is 4 mol% or less, preferably 3 mol% or less.
  • the NiSn alloy layer further contains Pd.
  • the Pd content at the boundary with the Ni layer is smaller than the Pd content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer.
  • the Pd content at the boundary with the Ni layer is 3 mol% or less, preferably 2 mol% or less.
  • the Ni layer is a UBM derived layer as described above.
  • the Ni layer has a Ni content of 83 mol% or more, preferably 85 mol% or more, at each distance within 0.2 [ ⁇ m] from the boundary with the NiSn alloy layer.
  • the Ni layer may contain an elemental component derived from UBM.
  • the Ni layer may contain P, for example.
  • the Ni layer is such that the Bi content at each distance within 0.2 [ ⁇ m] from the boundary with the NiSn alloy layer is 0.2 mol% or less, preferably 0.1 mol% or less. is there.
  • the Bi content at each distance from the boundary with the NiSn alloy layer is the above or less means that the Ni content at each distance from the boundary with the Ni layer in the NiSn alloy layer has the same meaning as described above. is there.
  • the Ni content in the Ni layer is extremely reduced, that is, the invasion of Bi is effectively prevented.
  • the (Cu, Ni, Pd) ⁇ Sn alloy layer is a layer of Sn alloy in which Cu, Ni, and Pd are in solid solution. It is considered that this (Cu, Ni, Pd) ⁇ Sn alloy layer is formed from the constituent elements of UBM and the solder alloy. In a preferred embodiment, the (Cu, Ni, Pd) ⁇ Sn alloy layer contains Cu, Ni, Pd, and Sn.
  • the Cu content at each distance from the boundary with the NiSn alloy layer is in the range of 10 mol% to 22 mol%, preferably 12 mol% to It is in the range of 20 mol %.
  • the Ni content at each distance from the boundary with the NiSn alloy layer is in the range of 13 mol% to 21 mol%, preferably 14 mol% to It is in the range of 20 mol %.
  • the Pd content at each distance from the boundary with the NiSn alloy layer is in the range of 5 mol% to 19 mol%, preferably 6 mol% to It is in the range of 18 mol %.
  • the Sn content at each distance from the boundary with the NiSn alloy layer is in the range of 44 mol% to 55 mol%, preferably 45 mol% to It is in the range of 54 mol %.
  • the (Cu, Ni, Pd) ⁇ Sn alloy layer further contains Bi.
  • the Bi content at the boundary with the NiSn alloy layer is 2 mol% or less, preferably 1 mol% or less.
  • the Bi content in the (Cu, Ni, Pd) ⁇ Sn alloy layer when the Bi content is measured according to the distance from the boundary with the NiSn alloy layer, the Bi content is 0.1 mol% to There is a distance in the range of 24 mol%, preferably in the range of 0.2 mol% to 23 mol%, or in the range of 1 mol% to 24 mol%, or in the range of 2 mol% to 23 mol%.
  • the (Cu, Ni, Pd) ⁇ Sn alloy layer has a peak of Bi content, and the peak is located away from the boundary with the NiSn alloy layer,
  • the NiSn alloy layer prevents Bi from entering from the Bi layer side. That is, in a preferred embodiment, the peak of Bi content present in the (Cu, Ni, Pd) ⁇ Sn alloy layer, and the peak of Bi content located away from the boundary with the NiSn alloy layer,
  • the Bi content is in the above range and is larger than the Bi content at the boundary with the NiSn alloy layer.
  • the Bi content at the boundary with the BiSn alloy layer is 0.5 mol% or less, preferably 0.4 mol% or less.
  • the BiSn alloy layer contains Bi and Sn.
  • the Bi content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is 0.5 mol% or less, preferably 0.4 mol% or less.
  • the Sn content at the boundary with the Bi layer is 2 mol% or less, preferably 1 mol% or less.
  • the BiSn alloy layer further contains Cu, Ni and Pd.
  • the Cu content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Cu content at the boundary with the Bi layer.
  • the Cu content at the boundary with the Bi layer is 0.5 mol% or less, preferably 0.3 mol% or less.
  • the Ni content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Ni content at the boundary with the Bi layer.
  • the Ni content at the boundary with the Bi layer is 1 mol% or less, preferably 0.5 mol% or less.
  • the Pd content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Pd content at the boundary with the Bi layer.
  • the Pd content at the boundary with the Bi layer is 0.6 mol% or less, preferably 0.3 mol% or less.
  • the Bi layer is a Bi layer continuous to the solder alloy side as described above, and contains Bi derived from the solder alloy as a main component.
  • the Bi layer has a Bi content of 97 mol% or more, preferably 98 mol% or more, at each distance within 0.2 [ ⁇ m] from the boundary with the BiSn alloy layer.
  • the Bi layer may contain an elemental component derived from the solder alloy.
  • phase liberated from the (Cu, Ni, Pd) ⁇ Sn alloy layer in the Bi layer there is no (Cu, Ni, Pd) ⁇ Sn alloy phase liberated from the (Cu, Ni, Pd) ⁇ Sn alloy layer in the Bi layer.
  • the phase of the (Cu, Ni, Pd) ⁇ Sn alloy released from the (Cu, Ni, Pd) ⁇ Sn alloy layer is specifically described as the phase in the image of the comparative example in Examples described later. This is the phase.
  • such phases are preferably absent, at least in the field of view under observation.
  • the concentration (mol %) of each element can be measured by the means disclosed in the examples described later, and specifically, it can be measured using STM (manufactured by JEOL, device name: JEM-2100F). You can The element concentration in the present invention means each element concentration when the total of Ni, Sn, Bi, Cu, Pd and P is set to 100 mol %.
  • the joint part according to the present invention can have a joint strength (shear strength) after being kept at a high temperature of 250° C. for 1000 hours, for example, 40 MPa or more, preferably 42 MPa or more. That is, it has excellent durability in a high temperature range.
  • This bonding strength can be measured by the procedure described later in the examples.
  • the reason why the joint of the present invention has excellent durability in a high temperature range is unknown, but from the comparison with Comparative Examples in Examples described later, the joint of the present invention has the above-mentioned layer structure. According to the present invention, it is possible to prevent the invasion of Bi from the Bi layer side to the Ni layer side by providing a predetermined NiSn alloy layer, thereby providing excellent characteristics. Have insight.
  • the present invention includes the following (1) and the following. (1) It is a joint part where the UBM and the solder alloy are joined, and in order from the UBM side, Ni layer continuous from the UBM side, NiSn alloy layer, (Cu, Ni, Pd) ⁇ Sn alloy layer, A BiSn alloy layer, A joint comprising a Bi layer continuous to the solder alloy side.
  • the NiSn alloy layer contains Ni, Sn, and P, In the NiSn alloy layer, the Ni content at the boundary with the Ni layer is larger than the Ni content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer, In the NiSn alloy layer, the Sn content at the boundary with the Ni layer is smaller than the Sn content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer, In the NiSn alloy layer, the Sn content at the boundary with the Ni layer is 0.4 mol% or less, In the NiSn alloy layer, the P content at the boundary with the Ni layer is larger than the P content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer, In the NiSn alloy layer, the P content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is 0.5 mol% or less, the joint according to (1).
  • the NiSn alloy layer contains Ni, Sn, and P, In the NiSn alloy layer, the Ni content at each distance from the boundary with the Ni layer is in the range of 21 mol% to 83 mol%, In the NiSn alloy layer, the Sn content at each distance from the boundary with the Ni layer is in the range of 0.2 mol% to 48 mol%, In the NiSn alloy layer, the joint portion according to any one of (1) to (2), wherein the P content at each distance from the boundary with the Ni layer is in the range of 0.1 mol% to 10 mol %.
  • the Cu content at the boundary with the Ni layer is smaller than the Cu content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer, The joint portion according to any one of (2) to (6), wherein in the NiSn alloy layer, the Cu content at the boundary with the Ni layer is 4 mol% or less.
  • the NiSn alloy layer further contains Pd, In the NiSn alloy layer, the Pd content at the boundary with the Ni layer is smaller than the Pd content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer, In the NiSn alloy layer, the joint portion according to any one of (2) to (7), wherein the Pd content at the boundary with the Ni layer is 3 mol% or less.
  • the Ni layer has a Bi content of 0.2 mol% or less at each distance within 0.2 [ ⁇ m] from the boundary with the NiSn alloy layer, and the bonding according to any one of (1) to (8) above. Department.
  • the (Cu, Ni, Pd) ⁇ Sn alloy layer contains Cu, Ni, Pd, and Sn, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Cu content at each distance from the boundary with the NiSn alloy layer is in the range of 10 mol% to 22 mol %, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Ni content at each distance from the boundary with the NiSn alloy layer is in the range of 13 mol% to 21 mol %, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Pd content at each distance from the boundary with the NiSn alloy layer is in the range of 5 mol% to 19 mol %, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Sn content at each distance from the Cu
  • the (Cu, Ni, Pd) ⁇ Sn alloy layer further contains Bi, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Bi content at the boundary with the NiSn alloy layer is 2 mol% or less, In the (Cu, Ni, Pd) ⁇ Sn alloy layer, when the Bi content is measured according to the distance from the boundary with the NiSn alloy layer, the Bi content is in the range of 0.1 mol% to 24 mol %. There is a distance, The joint portion according to (10), wherein in the (Cu, Ni, Pd) ⁇ Sn alloy layer, the Bi content at the boundary with the BiSn alloy layer is 0.5 mol% or less.
  • the BiSn alloy layer contains Bi and Sn, In the BiSn alloy layer, the Bi content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is 0.5 mol% or less, The joint portion according to any one of (1) to (11), wherein in the BiSn alloy layer, the Sn content at the boundary with the Bi layer is 2 mol% or less.
  • the BiSn alloy layer further contains Cu, Ni and Pd, In the BiSn alloy layer, the Cu content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Cu content at the boundary with the Bi layer, In the BiSn alloy layer, the Cu content at the boundary with the Bi layer is 0.5 mol% or less, In the BiSn alloy layer, the Ni content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Ni content at the boundary with the Bi layer, In the BiSn alloy layer, the Ni content at the boundary with the Bi layer is 1 mol% or less, In the BiSn alloy layer, the Pd content at the boundary with the (Cu, Ni, Pd) ⁇ Sn alloy layer is larger than the Pd content at the boundary with the Bi layer, In the BiSn alloy layer, the joint portion according to (12), wherein the Pd content at the boundary with the Bi layer is 0.6 mol% or less.
  • the UBM is the joint part according to any one of (1) to (14), which is a UBM formed by sequentially stacking nickel, palladium, and gold on an electrode.
  • the invention of the present application includes an electronic component, a power device, a printed circuit board, an LED, a flexible circuit material, and a heat dissipation material having the above-mentioned joint portion.
  • Example 1 [Formation of UBM] An Al surface (thickness: 3 ⁇ m) was formed on one surface of the Si wafer by sputtering, and a polyimide film was further formed by coating, and then a land having an opening with a diameter of 300 ⁇ m was formed in the polyimide film by exposure and development. Further, a Ni layer (thickness 2.5 ⁇ m), a Pd layer (thickness 0.05 ⁇ m), and an Au layer (thickness 0.02 ⁇ m) are sequentially formed on the land portion by electroless plating to form a UBM (Under Bump Metal). ) Is provided. Since the reducing agent for hypophosphite ions is added to the electroless Ni plating solution, P is codeposited on the Ni layer.
  • solder powder The composition of the solder powder used in Example 1 by ICP analysis is shown in Table 1. The solder powder used was 300 ⁇ m ⁇ .
  • EPMA analysis, STM analysis After that, the sample was encapsulated with resin and the cross section was polished. The cleaned and smoothed sample surface was analyzed by EPMA (manufactured by JEOL, device name: JXA-8500F). Since the thickness of the solder joint portion after the reflow treatment is about 1 ⁇ m or less, the solder joint portion was measured by a highly accurate STM (manufactured by JEOL, device name: JEM-2100F). Although the image accuracy of the measurement by EPMA is inferior to that of STM, image processing was performed with the size of one pixel being 0.08 ⁇ m. For further quantification, the same sample was thinly processed and measured by STM.
  • FIG. 1 shows an image of a composite map created by measuring the cross section of the joint portion of Example 1 immediately after the reflow treatment by EPMA.
  • Example 1 [Share strength measurement] The joint portion of Example 1 was subjected to shear strength measurement as described below after being held at a temperature of 250° C. for 1000 hours in the atmosphere after the reflow treatment described above. The results are shown in Table 1.
  • the bonding strength was measured according to MIL STD-883G.
  • the tool attached to the load sensor descends to the board surface, the device detects the board surface and stops descending, and the tool rises to the set height from the detected board surface and pushes the joint with the tool The load was measured.
  • the results are summarized in Table 1.
  • Comparative Example 1 As Comparative Example 1, a solder powder having a composition different from that of Example 1 is used, reflow treatment is performed under conditions different from those of Example 1, and the other steps are similar to those of Example 1 to form a joint. Then, EPMA measurement, STM measurement, and shear strength measurement were performed on this joint. Table 1 shows the ICP analysis value of the composition of the solder powder of Comparative Example 1 and the shear strength measurement result.
  • the reflow processing conditions of Comparative Example 1 were as follows: The temperature was raised from room temperature to 150°C at a heating rate of 0.9°C/sec. Next, the temperature was raised from 150° C. to 290° C. at a heating rate of 4.5° C./sec. Then the temperature of 290° C. was maintained for 40 seconds. Next, it was cooled from 290° C. to room temperature at an initial temperature decreasing rate of 8° C./sec. These operations were performed in a nitrogen atmosphere.
  • Fig. 3 shows an image of a composite map created by measuring the cross section of the joint of Comparative Example 1 immediately after the reflow treatment by EPMA.
  • FIG. 5 shows an STM image of the cross section of the joint portion of Example 1 immediately after the reflow treatment.
  • FIG. 6 is a graph showing the numerical value of each element concentration (mol %) along the analysis line written in this STM image for the joint portion of Example 1. Regarding the element concentration (mol %), the total of 6 elements in the graph, that is, Ni, Sn, Bi, Cu, Pd, and P was 100%.
  • FIG. 7 shows an STM image of the cross section of the joint of Comparative Example 1 immediately after the reflow treatment.
  • FIG. 8 is a graph showing the numerical value of each element concentration (mol %) along the analysis line written in this STM image for the joint portion of Comparative Example 1.
  • FIG. 1 is an EPMA composite map image after the reflow process of the joint portion of the first embodiment.
  • a layer considered as a (Cu, Ni, Pd) ⁇ Sn layer (13) was observed, and a (Cu, Ni, Pd) ⁇ Sn layer was observed.
  • the (Cu, Ni, Pd) ⁇ Sn layer (13) has a relatively uniform thickness, and is separated from the (Cu, Ni, Pd) ⁇ Sn layer (13) in the Bi layer (14). No (Cu,Ni,Pd) ⁇ Sn phase was observed. In FIG. 1, no penetration of Bi into the Ni layer (11) is observed even in the image of the colored composite map.
  • the black region occupying the lower half or more of the image of FIG. 1 is the Al layer (3 ⁇ m) that is the base of the Ni layer (11) and the Si base material that is the base of the Al layer.
  • FIG. 2 is an EPMA composite map image after holding for 1000 hours at a temperature of 250° C. after the reflow treatment of the joint portion in Example 1.
  • a layer that is considered to be a (Cu, Ni, Pd) ⁇ Sn layer (23) was observed, and a (Cu, Ni, Pd) ⁇ Sn layer was observed.
  • a NiSn alloy layer (having a thickness of about 0.2 ⁇ m) (22). No Bi intrusion is observed in the NiSn alloy layer (22) even in the image of the composite map that is colored.
  • the (Cu, Ni, Pd) ⁇ Sn layer (23) has an increased thickness as compared with FIG.
  • FIG. 3 is an EPMA composite map image after the reflow process of the joint portion of Comparative Example 1.
  • a layer that is considered to be a (Cu, Ni, Pd) ⁇ Sn layer (32) was observed, and a (Cu, Ni, Pd) ⁇ Sn layer was observed.
  • a layer (thickness: about 0.1 ⁇ m) which is also seen as a NiSn alloy layer (32′), but the NiSn(32′) alloy layer has a trace amount that cannot be observed in gray scale.
  • Bi intrusion (35) is observed in the image of the colorized composite map.
  • the (Cu, Ni, Pd) ⁇ Sn layer (32) has a non-uniform thickness, and is separated from this (Cu, Ni, Pd) ⁇ Sn layer (32) (Cu, Ni, Pd).
  • the ⁇ Sn phase (33) is observed in the Bi layer (34).
  • the penetration of Bi into the Ni layer (31) is not observed even in the image of the colorized composite map.
  • the black region occupying the lower half or more of the image of FIG. 3 is the Al layer (3 ⁇ m) that is the base of the Ni layer (31) and the Si base material that is the base of the Al layer.
  • FIG. 4 is an EPMA composite map image after holding for 1000 hours at a temperature of 250° C. after the reflow treatment of the joint portion of Comparative Example 1.
  • the Ni layer is present as in FIG. 3, but in the image of the colorized composite map, the penetration of Bi is observed in almost the entire thickness of the Ni layer (about 1.8 ⁇ m in thickness).
  • the Ni layer (42) is a thin Ni layer (42), and the Ni layer (41) in which no intrusion of Bi is observed is very thin (about 0.4 ⁇ m thick).
  • FIG. 5 is an STM image after the reflow processing of the joint portion in Example 1.
  • a layer that is considered to be a (Cu, Ni, Pd) ⁇ Sn layer (53) is observed in the vicinity of the interface between the Ni layer (51) and the Bi layer (54).
  • An area (52) as if an elongated hole is formed in the vertical direction is observed.
  • this region (52) is a P-rich region having a relatively high P concentration. The thickness of this P-rich region was about 0.13 ⁇ m.
  • FIG. 6 is a graph prepared by performing analysis along the analysis line (55) and measuring the concentration of atoms at each analysis point.
  • FIG. 6 is a graph in which the vertical axis represents the concentration (mol %) of atoms obtained by analysis along the analysis line (55) in FIG. 5 and the horizontal axis represents the distance from the analysis starting point of the analysis line. is there.
  • the left side of the graph is the Ni layer side
  • the right side of the graph is the Bi layer side.
  • the starting point of the horizontal axis is in the Ni layer. From 0.15 ⁇ m, the Ni concentration decreases, and near 0.22 ⁇ m, the Sn concentration begins to rise rapidly from the state where there is almost no Sn concentration. It is considered that the NiSn alloy layer starts from this position.
  • the P concentration at this position is relatively higher than before and after it, the P concentration decreases with increasing distance, and the P concentration almost disappears near 0.26 ⁇ m.
  • the Ni concentration decreases and the Sn concentration increases.
  • the NiSn alloy layer ends at the position where the P concentration disappears and a new (Cu, Ni, Pd) ⁇ Sn layer starts.
  • the Pd concentration is relatively higher than before and after it.
  • the Sn concentration is estimated to be 48 mol% and the Ni concentration is 21 mol%, and the value of ⁇ is 0.8.
  • the BiSn alloy layer Cu, Ni, and Pd are present in addition to Bi and Sn.
  • concentrations of Cu, Ni, and Pd in the BiSn alloy layer all decrease with an increase in the distance, and disappear in the vicinity of 0.56 ⁇ m. It is considered that the BiSn alloy layer ends and the Bi layer starts at the position where the Cu, Ni, and Pd concentrations disappear.
  • FIG. 7 is an STM image after the reflow process of the joint portion of Comparative Example 1.
  • a layer considered to be a (Cu, Ni, Pd) ⁇ Sn layer (73) is observed near the interface between the Ni layer (71) and the Bi layer (74).
  • the P-rich region (72) which seems to have an elongated hole in the up-and-down direction, is slightly uneven in shape as compared with FIG. 5, the analysis is performed along the observed analysis line (75).
  • FIG. 8 is a graph created by measuring the concentration of atoms at each analysis point.
  • FIG. 8 is a graph in which the vertical axis represents the concentration (mol %) of atoms obtained by analysis along the analysis line (75) in FIG. 7 and the horizontal axis represents the distance from the analysis starting point of the analysis line. is there.
  • the left side of the graph is the Ni layer side
  • the right side of the graph is the Bi layer side.
  • Bi penetrates to the position corresponding to the boundary between the NiSn alloy layer and the (Cu, Ni, Pd) ⁇ Sn layer, and in the graph of FIG.
  • the graph of FIG. 6 it is observed that Bi penetrates through the position corresponding to the NiSn alloy layer to the position corresponding to the Ni layer in the graph of FIG.
  • the Sn concentration is estimated to be 18 mol% and the Ni concentration is estimated to be 23 mol%. It became 0.0.
  • the ⁇ of the (Cu, Ni, Pd) ⁇ Sn layer was estimated to be 0.7 to 1.2, and the average value was 0.85.
  • the present invention provides a solder joint portion having excellent durability in a high temperature range without containing lead added.
  • the present invention is an industrially useful invention.
  • Ni layer 12 NiSn alloy layer 13 (Cu, Ni, Pd) ⁇ Sn layer 14 Bi layer 21 Ni layer 22 NiSn alloy layer 23 (Cu, Ni, Pd) ⁇ Sn layer 24 Bi layer 31 Ni layer (no Bi penetration) 32 (Cu,Ni,Pd) ⁇ Sn layer 32′ NiSn alloy layer 33 Free (Cu,Ni,Pd) ⁇ Sn phase 34 Bi layer 35 Penetration Bi 41 Ni layer (no Bi penetration) 42 Ni layer (with Bi intrusion) 43' NiSn alloy phase (discontinuous) 43 (Cu, Ni, Pd) ⁇ Sn layer 44 Free (Cu, Ni, Pd) ⁇ Sn phase 45 Bi layer 46 Ni phase 51 Ni layer 52 P rich region 53 (Cu, Ni, Pd) ⁇ Sn layer 54 Bi layer 55 Analysis line 71 Ni layer 72 P rich region 73 (Cu, Ni, Pd) ⁇ Sn layer 74 Bi layer 75 Analysis line

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Mechanical Engineering (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
  • Electroplating Methods And Accessories (AREA)

Abstract

Un joint à brasure tendre, qui présente une excellente durabilité dans une plage de températures élevées, est formé au moyen d'un joint qui lie un UBM et un alliage de brasage tendre et qui contient, dans l'ordre à partir du côté UBM, une couche de Ni reliée du côté UBM, une couche d'alliage de NiSn, une couche d'alliage de (Cu, Ni, Pd)αSn, une couche d'alliage de BiSn, et une couche de Bi reliée au côté d'alliage de brasage tendre.
PCT/JP2019/031255 2018-12-28 2019-08-07 Joint à brasure tendre WO2020136979A1 (fr)

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JP2020502503A JPWO2020136979A1 (ja) 2018-12-28 2019-08-07 はんだ接合部
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JP2011014705A (ja) * 2009-07-01 2011-01-20 Hitachi Ltd 半導体装置および半導体装置の製造方法
JP2013093547A (ja) * 2011-10-05 2013-05-16 Fujitsu Ltd 半導体装置、電子装置、半導体装置の製造方法
WO2014115798A1 (fr) * 2013-01-28 2014-07-31 株式会社村田製作所 Procédé de formation de perle de soudure et perle de soudure
WO2014170994A1 (fr) * 2013-04-18 2014-10-23 千住金属工業株式会社 Alliage de soudage sans plomb
JP2015072996A (ja) * 2013-10-02 2015-04-16 新光電気工業株式会社 半導体装置
US20170368644A1 (en) * 2016-06-23 2017-12-28 Purdue Research Foundation Transient liquid phase bonding process and assemblies formed thereby
JP2018047497A (ja) * 2016-09-23 2018-03-29 住友金属鉱山株式会社 Ｂｉ基はんだ合金及びその製造方法、並びに、そのはんだ合金を用いた電子部品及び電子部品実装基板

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US6630251B1 (en) * 2002-09-23 2003-10-07 Delphi Technologies, Inc. Leach-resistant solder alloys for silver-based thick-film conductors
JP4481986B2 (ja) * 2003-08-06 2010-06-16 ミシガン ステイト ユニバーシティー 複合金属マトリックス鋳物およびはんだ組成物、並びに方法
US7915741B2 (en) * 2009-02-24 2011-03-29 Unisem Advanced Technologies Sdn. Bhd. Solder bump UBM structure
TWI423358B (zh) * 2011-08-04 2014-01-11 Nippon Steel & Sumikin Mat Co Solder balls and electronic components for semiconductor encapsulation

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Publication number Priority date Publication date Assignee Title
JP2011014705A (ja) * 2009-07-01 2011-01-20 Hitachi Ltd 半導体装置および半導体装置の製造方法
JP2013093547A (ja) * 2011-10-05 2013-05-16 Fujitsu Ltd 半導体装置、電子装置、半導体装置の製造方法
WO2014115798A1 (fr) * 2013-01-28 2014-07-31 株式会社村田製作所 Procédé de formation de perle de soudure et perle de soudure
WO2014170994A1 (fr) * 2013-04-18 2014-10-23 千住金属工業株式会社 Alliage de soudage sans plomb
JP2015072996A (ja) * 2013-10-02 2015-04-16 新光電気工業株式会社 半導体装置
US20170368644A1 (en) * 2016-06-23 2017-12-28 Purdue Research Foundation Transient liquid phase bonding process and assemblies formed thereby
JP2018047497A (ja) * 2016-09-23 2018-03-29 住友金属鉱山株式会社 Ｂｉ基はんだ合金及びその製造方法、並びに、そのはんだ合金を用いた電子部品及び電子部品実装基板

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CN111630646A (zh) 2020-09-04
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JPWO2020136979A1 (ja) 2021-09-09

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