Au-Sn ALLOY, Au-Sn ALLOY POWDER, Au-Sn ALLOY PASTE, AND Au-Sn ALLOY JOINT LAYER

Abstract

To provide an Au-Sn alloy, an Au-Sn alloy powder, an Au-Sn alloy paste, and an Au-Sn alloy bonding layer that are excellent in heat resistance, have a low α-ray emission amount, and exhibit high reliability.SOLUTION: The Sn content is in a range of at least 15.0 mass% and 25.0 mass% or less, with the balance consisting of Au and impurities, and the α-ray emission amount is 0.010 cph / cm2 or less. It is preferable that the contents of Cu, Pb, As, Sb, and Ag included as impurities are each 10 mass ppm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an Au—Sn alloy, an Au—Sn alloy powder, an Au—Sn alloy paste, and an Au—Sn alloy bonding layer. [Background technology]

[0002] Generally, various devices such as LEDs and power modules have a structure in which electronic components such as semiconductor elements are bonded to a circuit layer formed on a substrate. Here, when electronic components such as semiconductor elements are bonded to a circuit layer, a method using a solder material is widely used, as shown in Patent Document 1. Conventionally, as the above-mentioned solder material, for example, a Sn-Pb alloy-based solder material has been widely used.

[0003] In recent years, regulations on environmentally harmful chemical substances have become increasingly strict, and the use of Pb in solder materials has also been restricted. In response to this, lead-free solders such as Sn-Ag alloy solder materials and Sn-Ag-Cu alloy solder materials have been proposed, as shown in Patent Document 2, for example.

[0004] Recently, the heat resistance of semiconductor elements has improved, and the amount of heat generated by semiconductor elements has increased due to the large currents that are loaded on the semiconductor elements. For this reason, solder materials are required to have even greater heat resistance than before. Here, lead-free solders such as the above-mentioned Sn—Ag alloy solder material and Sn—Ag—Cu alloy solder material have a relatively low melting point (eutectic temperature), and therefore have insufficient heat resistance.

[0005] Therefore, as a solder material with excellent heat resistance, for example, an Au—Sn alloy solder material is proposed in Patent Document 3. This Au—Sn alloy solder material has a higher melting point (eutectic temperature) than the above-mentioned Sn—Ag alloy solder material, Sn—Ag—Cu alloy solder material, etc., and has excellent heat resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-172378 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-321982 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-200794 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, it is known that in semiconductor devices incorporating semiconductor elements, alpha rays are emitted from the solder that forms the bonding layer, and these alpha rays may affect the semiconductor elements and cause soft errors. In particular, recent semiconductor devices have become increasingly dense, and the risk of soft errors occurring due to the influence of alpha rays from solder located near semiconductor elements is increasing. Lead contains a radioactive nuclide that emits alpha rays. 210 Po and its parent nuclide 210 Since Sn-Pb alloy solder contains trace amounts of Pb, there is a risk that alpha rays may also be emitted from the Pb contained in the solder.

[0008] Lead-free solder materials such as the above-mentioned Sn-Ag alloy solder material and Sn-Ag-Cu alloy solder material are primarily composed of Sn and do not contain Pb, and are therefore expected to have lower alpha ray counts than Sn-Pb alloy solder material. However, even with these lead-free solders, it is sometimes not possible to sufficiently reduce the amount of alpha ray emitted, and research is underway to reduce the amount of alpha ray emitted. On the other hand, no study has been done on alpha rays for the Au-Sn alloy solder material mentioned above. Currently, common Au and Sn raw materials emit high amounts of alpha rays, and it is not easy to reduce the amount of alpha rays emitted by Au-Sn alloy solder material.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an Au-Sn alloy, an Au-Sn alloy powder, an Au-Sn alloy paste, and an Au-Sn alloy bonding layer that have excellent heat resistance, low alpha ray emission, and excellent reliability. [Means for solving the problem]

[0010] In order to solve the above problems, the Au-Sn alloy of the first aspect of the present invention has an Sn content in the range of 15.0 mass % to 25.0 mass % and the remainder consisting of Au and impurities, and has an α-ray emission rate of 0.010 cph / cm 2 It is characterized by the following:

[0011] According to the Au-Sn alloy of the first aspect of the present invention, the Sn content is within the range of 15.0 mass % or more and 25.0 mass % or less, with the remainder being composed of Au and impurities, so that the melting point is relatively high and the heat resistance is excellent. And the alpha ray emission rate is 0.010cph / cm 2 Since the resistance is limited to the following value, it is possible to suppress the occurrence of soft errors in semiconductor devices and the like, resulting in excellent reliability.

[0012] The Au—Sn alloy of aspect 2 of the present invention is characterized in that, in the Au—Sn alloy of aspect 1 of the present invention, the contents of Cu, Pb, As, Sb, and Ag contained as the impurities are each 10 mass ppm or less. According to the Au-Sn alloy of the second aspect of the present invention, the contents of Cu, Pb, As, Sb, and Ag contained as the impurities are each limited to 10 mass ppm or less, so that the strength reduction due to ion migration or the formation of unintended intermetallic compounds does not occur, and the alloy has excellent reliability.

[0013] The Au—Sn alloy of aspect 3 of the present invention is the Au—Sn alloy of aspect 1 or aspect 2 of the present invention, characterized in that the contents of Pb and Bi contained as impurities are each less than 1 ppm by mass. According to the Au-Sn alloy of the third aspect of the present invention, the contents of Pb and Bi contained as the impurities are each limited to less than 1 mass ppm, which reduces the contents of Pb and Bi, which contain radioactive isotopes, and further reduces the possibility of soft errors in semiconductor devices and the like due to alpha ray emissions.

[0014] The Au—Sn alloy powder of the fourth aspect of the present invention is characterized by comprising the Au—Sn alloy of any one of the first to third aspects of the present invention. The Au-Sn alloy powder of aspect 4 of the present invention is composed of the Au-Sn alloy of aspects 1 to 3 of the present invention, and therefore has excellent heat resistance, sufficiently low alpha ray emission, can suppress the occurrence of soft errors in semiconductor elements, etc., and is therefore excellent in reliability.

[0015] The Au—Sn alloy paste of the fifth aspect of the present invention is characterized by containing the Au—Sn alloy powder of the fourth aspect of the present invention. The Au-Sn alloy paste of the fifth aspect of the present invention contains the Au-Sn alloy powder of the fourth aspect of the present invention, and by applying and firing it, it is possible to obtain a molten solid of an Au-Sn alloy that has excellent heat resistance, emits sufficiently low alpha rays, can suppress the occurrence of soft errors in semiconductor elements, etc., and is therefore highly reliable.

[0016] The Au-Sn alloy bonding layer of aspect 6 of the present invention is an Au-Sn alloy bonding layer formed between a first member and a second member in a bonded body in which the first member and the second member are bonded, and is characterized by being made of a molten solid of the Au-Sn alloy paste of aspect 5 of the present invention. The Au-Sn alloy paste of aspect 6 of the present invention is composed of a molten solid of the Au-Sn alloy paste of aspect 5 of the present invention, and therefore has excellent heat resistance, a sufficiently low amount of alpha rays emitted, and is capable of suppressing the occurrence of soft errors in semiconductor elements and the like, resulting in excellent reliability. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an Au-Sn alloy, an Au-Sn alloy powder, an Au-Sn alloy paste, and an Au-Sn alloy bonding layer that have excellent heat resistance, low alpha ray emission, and excellent reliability. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an explanatory diagram of a bonded body provided with an Au—Sn alloy bonding layer according to one embodiment of the present invention. [Figure 2] 1 is a phase diagram of an Au-Sn alloy. [Figure 3] 1 is a flow diagram of a method for producing an Au—Sn alloy powder according to the present embodiment. [Figure 4] FIG. 2 is a flow diagram of a method for producing the bonded body shown in FIG. [Figure 5] 2 is an explanatory diagram of a method for manufacturing the bonded body shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE INVENTION Hereinafter, an Au—Sn alloy, an Au—Sn alloy powder, an Au—Sn alloy paste, and an Au—Sn alloy bonding layer according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] The Au—Sn alloy, Au—Sn alloy powder, and Au—Sn alloy paste according to this embodiment are used to manufacture a bonded body 10 by bonding a first member 11 and a second member 12, as shown in Fig. 1. The Au—Sn alloy bonding layer 13 according to this embodiment is formed between the bonded first member 11 and second member 12. In this embodiment, the bonded body 10 is a semiconductor device in which a circuit layer (first member 11) of an insulating circuit board and a semiconductor element (second member 12) are bonded via an Au—Sn alloy bonding layer 13.

[0021] The Au—Sn alloy of this embodiment has a composition in which the Sn content is in the range of 15.0 mass % to 25.0 mass % and the remainder is Au and impurities. Here, the phase diagram of the Au-Sn alloy is shown in Figure 2. As shown in Figure 2, the Au-Sn alloy is a eutectic type alloy that undergoes a eutectic reaction, with a Sn content of approximately 20.0 mass% forming a eutectic composition, and its melting point being the eutectic temperature of 278°C.

[0022] In the Au-Sn alloy of this embodiment, the alpha ray emission rate is 0.010 cph / cm 2 It is stated as follows. Here, the amount of α-ray emission from the Au—Sn alloy in this embodiment was measured at room temperature using a gas flow type α-ray measurement device (MODEL-1950, measurement lower limit: 0.0005 cph / cm) manufactured by Alpha Science Co., Ltd. 2 ) for 96 hours.

[0023] In the Au—Sn alloy of this embodiment, the content of each of Cu, Pb, As, Sb, and Ag contained as impurities is preferably 10 mass ppm or less. As described above, by specifying the content of specific elements contained as impurities, it is possible to sufficiently reduce the amount of α-ray emission and stabilize various properties such as electrical conductivity, thermal conductivity, and strength.

[0024] In the Au—Sn alloy of this embodiment, the contents of Pb and Bi contained as the impurities are preferably each less than 1 ppm by mass. As mentioned above, the content of Pb and Bi contained as impurities is limited to less than 1 mass ppm each, which reduces the content of Pb and Bi, which contain radioactive isotopes, and further reduces the possibility of soft errors in semiconductor devices and the like due to alpha ray emissions.

[0025] The Au—Sn alloy powder of this embodiment is made of the Au—Sn alloy of this embodiment. Here, the Au—Sn alloy powder of this embodiment is produced, for example, by gas atomizing a molten Au—Sn alloy. The average particle size (D50) of the Au—Sn alloy powder of this embodiment is preferably within the range of 5 μm or more and 30 μm or less. The particle size of the Au-Sn alloy powder can be obtained, for example, by measuring the projected area of ​​the Au-Sn alloy powder using a scanning electron microscope (SEM), calculating the equivalent circle diameter from the obtained projected area, and converting the calculated particle size into a volume-based particle size.

[0026] Here, an example of a method for producing the Au—Sn alloy powder according to this embodiment will be described with reference to the flow diagram of Fig. 3. In this embodiment, the Au—Sn alloy powder is produced by gas atomization.

[0027] (Dissolved raw material preparation process S01) First, a melting material for gas atomization is prepared. As the melting material, for example, the following materials (1) to (4) can be used. (1) Measure the alpha ray emission in advance and check that the alpha ray emission is 0.010 cph / cm 2 The following Au raw material and Sn raw material are selected and weighed so that the Sn content is within the range of 15.0 mass% to 25.0 mass%. The selection method may involve measuring each raw material lot, or cutting and dividing one lot and selecting the low-alpha-ray portion.

[0028] (2) Measure the alpha ray emission in advance and check that the alpha ray emission is 0.010 cph / cm 2 The Au-Sn alloy ingot is obtained by selecting the following Au raw material and Sn raw material, weighing them so that the Sn content is within the range of 15.0 mass% to 25.0 mass%, and melting and casting them. The selection method may involve measuring each raw material lot, or cutting and dividing one lot and selecting the low-alpha-ray portion.

[0029] (3) The Au raw material and the Sn raw material are weighed so that the Sn content is within the range of 15.0 mass% to 25.0 mass%, and then melted and cast to obtain an Au-Sn alloy ingot. The Au-Sn alloy ingot is divided into blocks, and the alpha ray emission rate is measured for each divided block. The alpha ray emission rate is 0.010 cph / cm 2 The following blocks are selected: In the case of an ingot whose surface layer has become highly alpha-ray emitting due to prolonged heating, the surface layer may be removed and an inner block with low alpha-ray emission may be selected.

[0030] (4) Au-Sn alloy ingots are produced by weighing out Au and Sn raw materials, melting them in air to generate Sn oxides (dross), and then removing the dross to cast them. When the Sn oxides (dross) are generated, the impurity Pb ​​is sublimated and removed as PbO, reducing the amount of alpha-ray emissions. In addition to Pb, Bi is also easily oxidized and can be removed as Bi2O3. Therefore, compared to the above-mentioned methods, the method shown in (4) can further reduce the amount of Pb and Bi contained as impurities.

[0031] (Atomization process S02) The above-mentioned melting raw material is melted, for example, in a high-frequency melting furnace, and gas atomized to produce Au—Sn alloy powder. There are no particular restrictions on the Au-Sn alloy powder, but the molten metal temperature is preferably in the range of 600°C or higher and 1000°C or lower.

[0032] (Classification process S03) If necessary, the resulting gas atomized powder is classified, for example, by sieving it through a sieve, to obtain an Au—Sn alloy powder having a predetermined particle size distribution.

[0033] The Au—Sn alloy powder of this embodiment is produced by the melting raw material preparation step S01, the atomization step S02, and the classification step S03 described above.

[0034] The Au—Sn alloy paste of this embodiment contains the Au—Sn alloy powder of this embodiment and a flux. Here, the flux contains one or more of a solvent, an activator, a plasticizer, and a resin. As the flux, for example, a general flux (e.g., a flux containing rosin, an activator, a solvent, a thickener, etc.) can be used. The Au—Sn alloy paste of this embodiment preferably has a viscosity in the range of 20 Pa·s to 300 Pa·s.

[0035] Examples of the solvent that can be used include alcohols, ketones, esters, ethers, aromatic solvents, hydrocarbons, terpenes, and terpenoid solvents. Specific examples include benzyl alcohol, ethanol, ethyl alcohol, isopropyl alcohol, butanol, diethylene glycol, ethylene glycol, ethyl cellosolve, butyl cellosolve, butyl carbitol, isopropyl alcohol, ethyl acetate, butyl acetate, butyl benzoate, diethyl adipate, dodecane, tetradecene, α-terpineol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, toluene, xylene, propylene glycol monophenyl ether, diethylene glycol monohexyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diisobutyl adipate, hexylene glycol, cyclohexanedimethanol, 2-terpinyloxyethanol, 2-dihydroterpinyloxyethanol, citral, linalool, limonene, carvacrol, pinene, and farnesene, which can be used alone or in combination.

[0036] Examples of plasticizers that can be used include hydrogenated castor oil, hydrogenated castor oil, carnauba wax, amides, hydroxy fatty acids, dibenzylidene sorbitol, bis(p-methylbenzylidene)sorbitols, beeswax, stearic acid amide, and hydroxystearic acid ethylene bisamide, either alone or in combination. Examples of active agents that can be added include fatty acids such as adipic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, hydroxy fatty acids such as 1,2-hydroxystearic acid, antioxidants, surfactants, and amines. As the resin, for example, polymerized rosin, natural rosin, purified rosin, etc. can be used.

[0037] The Au—Sn alloy paste of this embodiment is produced by kneading the above-mentioned flux with the Au—Sn alloy powder of this embodiment. The kneading method is not particularly limited, and may be manual stirring or a kneading device such as a three-roll mill.

[0038] Next, a method for manufacturing the bonded body 10 shown in FIG. 1 (the bonded body 10 having the Au—Sn alloy bonding layer 13 of this embodiment) using the Au—Sn alloy paste of this embodiment will be described with reference to FIGS. 4 and 5.

[0039] (Paste application process S11) 5, the Au—Sn alloy paste 23 of this embodiment is applied to one or both of the joining surface of the first member 11 and the joining surface of the second member 12. The application method is not particularly limited, and examples thereof include a metal mask method, a screen printing method, and a dispensing method.

[0040] (Lamination step S12) Next, as shown in FIG. 5, the first member 11 and the second member 12 are laminated together with the Au—Sn alloy paste 23 interposed therebetween.

[0041] (Joining process S13) Next, as shown in Figure 5, the first member 11 and the second member 12 stacked with the Au-Sn alloy paste 23 interposed therebetween are heat-treated to melt the Au-Sn alloy paste 23 to produce a liquid phase, and this liquid phase is solidified to form an Au-Sn alloy bonding layer 13 consisting of a molten solid of the Au-Sn alloy paste 23, thereby bonding the first member 11 and the second member 12.

[0042] The holding temperature in the bonding step S13 is preferably within a range of the melting point of the Au—Sn alloy paste 23 +5° C. or more and the melting point +20° C. or less. Furthermore, the holding time at the holding temperature is preferably within the range of 1 second to 30 minutes. In the bonding step S13, pressure of 0.1 MPa or more and 10 MPa or less may be applied in the stacking direction. Furthermore, the atmosphere in the joining step S13 is preferably selected appropriately depending on the flux contained therein, such as an inert gas atmosphere such as Ar or N2, or a reducing atmosphere containing formic acid or hydrogen.

[0043] The bonded body 10 shown in FIG. 1 is manufactured by the paste application step S11, the lamination step S12, and the bonding step S13 described above.

[0044] The Au-Sn alloy, Au-Sn alloy powder, Au-Sn alloy paste, and Au-Sn alloy bonding layer 13 of this embodiment configured as described above have a Sn content in the range of 15.0 mass % to 25.0 mass % with the remainder consisting of Au and impurities, and therefore have a relatively high melting point and excellent heat resistance. And the alpha ray emission rate is 0.010cph / cm 2 Since the resistance is limited to the following value, it is possible to suppress the occurrence of soft errors in semiconductor devices and the like, resulting in excellent reliability.

[0045] Furthermore, in this embodiment, when the content of each of Cu, Pb, As, Sb, and Ag contained as impurities is 10 mass ppm or less, various characteristics are stable and reliability is excellent.

[0046] Furthermore, in this embodiment, when the content of Pb and Bi contained as the impurities is each less than 1 mass ppm, the occurrence of soft errors in semiconductor elements and the like can be suppressed, and the impurities can be further reduced.

[0047] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention. In this embodiment, the Au—Sn alloy powder is described as being produced by a gas atomization method, but this is not limited to this, and it may also be produced by other powdering techniques, such as a pulverization method or a wet synthesis method. [Example]

[0048] The results of confirmation experiments conducted to confirm the effectiveness of the present invention will be described below. The alpha dose of the Au and Sn raw materials used was measured in advance and kept below 0.010 cph / cm 2 and 0.010 cph / cm 2 We used products that had undergone a selection process to separate those that exceeded the standard.

[0049] (Examples 1-3, Example 7, Comparative Examples 1-3) The Au raw material and Sn raw material with the alpha dose and impurity amount shown in Table 1 were weighed so as to have the Sn content shown in Table 1, and these were used as melted raw materials and gas atomized to produce Au-Sn alloy powder.

[0050] (Example 4, Comparative Example 4) Au and Sn raw materials with the alpha doses and impurity amounts shown in Table 1 were weighed to obtain the Sn contents shown in Table 1, and then melted and cast to produce Au-Sn alloy ingots. This Au-Sn alloy ingot was used as the melting raw material and gas atomized to produce Au-Sn alloy powder.

[0051] Example 5 The Au and Sn raw materials with alpha doses and impurity amounts shown in Table 1 are conventional, general-purpose products for which no consideration has been given to reducing alpha ray emissions. These were weighed to achieve the Sn content shown in Table 1, and then melted and cast to produce Au-Sn alloy ingots. This Au-Sn alloy ingot was divided into six blocks, and the alpha ray emission rate of each block was measured. The alpha ray emission rate was found to be 0.010 cph / cm.2 The following selected blocks were used as melted raw materials and gas atomized to produce Au-Sn alloy powder.

[0052] Example 6 The Au and Sn raw materials with alpha doses and impurity amounts shown in Table 1 are conventional, general-purpose products for which no consideration has been given to reducing alpha ray emissions. These were weighed to achieve the Sn content shown in Table 1, and then melted and cast to produce Au-Sn alloy ingots. At this time, Sn oxide (dross) was generated by melting in air, and this Sn oxide (dross) was removed to produce the Au-Sn alloy ingots. The Au-Sn alloy ingot was used as a melting material and gas atomized to produce Au-Sn alloy powder.

[0053] The Au-Sn alloy powder obtained as described above was mixed with a commercially available RMA (mildy activated rosin base) flux to obtain an Au-Sn alloy paste, with the Au-Sn alloy powder content at 93 mass % and the flux content at 7 mass %.

[0054] A copper substrate (2 mm thick) with a gold-plated bonding surface and a 1 mm square Si element (400 μm thick) with a gold-plated bonding surface were prepared. The above-mentioned Au—Sn alloy paste was applied to the surface of a copper substrate using a metal mask method to form a paste layer with a thickness of 50 μm and an area of ​​φ1 mm. Next, a Si element was stacked on this paste layer, and the resulting mixture was placed in a heating furnace in a nitrogen atmosphere and held at 300°C for 1 minute to produce a bonded assembly in which the copper substrate and the Si element were bonded via an Au-Sn alloy bonding layer. The impurity concentration and α-ray emission of the resulting Au—Sn alloy bonding layer were measured. The measurement results are shown in Table 1.

[0055] The amount of alpha-ray emission was measured at room temperature using a gas flow type alpha-ray measuring device manufactured by Alpha Science (MODEL-1950, lower limit of measurement: 0.0005 cph / cm 2 ) for 96 hours.

[0056] The amount of impurities was obtained by dissolving the sample in aqua regia and analyzing the resulting solution with an ICP (plasma emission spectrometer, lower limit of quantification: 1 mass ppm).

[0057] The bond strength of the resulting bonded body was measured using a shear strength evaluation tester (Bond Tester MFM1500HF manufactured by TryPrecision). The measurement was performed by fixing the copper substrate of the bonded body horizontally and using a shear tool at a position 100 μm above the surface of the bonding layer, pushing the Si element horizontally from the side, measuring the strength at which the Si element broke. The shear tool movement speed was 0.1 mm / s. Three tests were conducted for each condition, and the arithmetic average of these values ​​was used as the measurement value. A bonding strength of 50 MPa or more was marked "Good", and a bonding strength of less than 50 MPa was marked "Poor".

[0058] [Table 1]

[0059] In Comparative Example 1, the alpha ray emission rate of the Au-Sn alloy bonding layer was 0.010 cph / cm 2 It exceeded that. In Comparative Example 2, the Sn content was as high as 30 mass %, and an Au—Sn alloy bonding layer could not be formed. In Comparative Example 3, the Sn content was as low as 10 mass %, and an Au—Sn alloy bonding layer could not be formed. In Comparative Example 4, the alpha ray emission rate of the Au-Sn alloy bonding layer was 0.010 cph / cm 2 It exceeded that.

[0060] In contrast, in Examples 1 to 7, the Au—Sn alloy bonding layer was stably formed, and the α-ray emission rate of the Au—Sn alloy bonding layer was 0.010 cph / cm 2 It was confirmed that the occurrence of soft errors in semiconductor elements can be suppressed.

[0061] In particular, in Example 6, it was confirmed that as a result of removing the oxides (dross) of Sn, Pb and Bi were also removed as oxides, resulting in a further reduction in impurities.

[0062] From the above, it has been confirmed that the present invention can provide an Au-Sn alloy, Au-Sn alloy powder, Au-Sn alloy paste, and Au-Sn alloy bonding layer that have excellent heat resistance, low alpha ray emission, and excellent reliability. [Explanation of symbols]

[0063] 10 zygote 11 First member 12 Second member 13 Au-Sn alloy bonding layer

Claims

1. The Sn content is within a range of 15.0 mass % or more and 25.0 mass % or less, and the remainder is Au and impurities, Alpha ray emission rate is 0.010 cph / cm ２ An Au—Sn alloy characterized by:

2. 2. The Au—Sn alloy according to claim 1, wherein the content of each of Cu, Pb, As, Sb, and Ag contained as impurities is 10 mass ppm or less.

3. 2. The Au—Sn alloy according to claim 1, wherein the contents of Pb and Bi contained as impurities are each less than 1 ppm by mass.

4. 3. The Au—Sn alloy according to claim 2, wherein the contents of Pb and Bi contained as impurities are each less than 1 ppm by mass.

5. Au—Sn alloy powder comprising the Au—Sn alloy according to any one of claims 1 to 4.

6. 6. An Au—Sn alloy paste comprising the Au—Sn alloy powder according to claim 5.

7. An Au—Sn alloy bonding layer formed between a first member and a second member in a bonded body in which the first member and the second member are bonded, 7. An Au—Sn alloy bonding layer comprising a molten solid of the Au—Sn alloy paste according to claim 6.

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