The conjugate, the method for manufacturing the conjugate, and the method for assessing the organic residues in the conjugate.

Abstract

A joint (10) is formed by joining a first component (11) and a second component (12) via a welding layer (13), wherein the joint (10) is immersed in isopropanol to extract organic residues contained in the joint (10), the UV absorption spectrum of the extract from which the aforementioned organic residues are extracted is measured, the obtained UV absorption spectrum is standardized with absorbance at a wavelength of 207 nm set to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less.

Description

Technical Field

[0001] []

[0002] The present invention relates to a joint formed by joining a first component and a second component via a weld layer, a method for manufacturing the joint, and a method for evaluating the organic residues in the joint. This case concerns the assertion of priority of Japanese Special Application No. 2021-146645 filed in Japan on September 9, 2021, and its contents are hereby incorporated. Prior Technology

[0003] For example, in various devices such as LEDs or power modules, the structure is generally formed by bonding electronic components such as semiconductor elements onto a circuit layer made of metal components. Therefore, when bonding electronic components such as semiconductor devices to the circuit layer, as shown in, for example, Patent Documents 1 and 2, the industry widely uses soldering materials. In recent years, from an environmental perspective, lead-free solders such as Sn-Ag, Sn-In, or Sn-Ag-Cu have become the mainstream. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2011-083809 [Patent Document 2] Japanese Patent No. 6566095 Summary of the Invention

[0005] [The problem that the invention aims to solve]

[0006] Furthermore, as described in Patent Documents 1 and 2, in various devices (bonded bodies) formed by bonding electronic components such as semiconductor elements to circuit layers using solder, residues of organic components contained in the solder (organic residues) may remain in the solder layer. Therefore, there is a risk of reduced bond strength. Moreover, organic residues may adversely affect the substrate surface, LEDs, power modules, and other devices. During subsequent steps such as wire bonding, organic residues may hinder the adhesion between the leads and the substrate surface, potentially leading to reduced bond strength.

[0007] Therefore, as methods for assessing organic residues, examples include the determination of organic matter using the TG-DTA method, or the estimation of the amount of organic matter by measuring the conductivity of the cleaning solution used to clean the conjugate. However, the TG-DTA method lacks sufficient accuracy to assess trace amounts of organic residues. Furthermore, methods for determining the conductivity of the cleaning solution used to clean conjugates cannot adequately assess weakly ionic organic components. Therefore, it is not possible to accurately assess organic residues in joints formed by welding layers, and it is not easy to provide joints with a genuine reduction in organic residues.

[0008] This invention was made in view of the aforementioned facts, and aims to provide a joint in which organic residues are sufficiently and reliably reduced in a joint formed by welding layers, thereby suppressing problems such as reduced joint strength caused by organic residues, a method for manufacturing the joint, and an organic residue assessment method for the joint that can accurately assess the amount of organic residues. [Methods for solving problems]

[0009] To solve the above-mentioned problems, the present invention provides a bonding system in which a first component and a second component are bonded together via a welding layer. The system is characterized in that the bond is immersed in isopropanol to extract the organic residue contained in the bond, the UV absorption spectrum of the extract containing the organic residue is measured, and the obtained UV absorption spectrum is standardized with the absorbance at a wavelength of 207 nm set to 100. The absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less.

[0010] According to the present invention, since the organic residue contained in the aforementioned conjugate is extracted by immersing the conjugate in isopropanol and the UV absorption spectrum of the extract containing the aforementioned organic residue is measured, the amount of organic residue contained in the conjugate can be accurately assessed. Then, the obtained UV absorption spectrum was standardized by setting the absorbance at a wavelength of 207 nm to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum was limited to 4 or less. Therefore, the amount of organic residues contained in the bond is sufficiently reduced, which can suppress the occurrence of problems such as reduced bonding strength caused by organic residues.

[0011] The manufacturing method of the joint of the present invention is a method for manufacturing a joint formed by joining a first component and a second component through a welding layer. It is characterized by comprising: a lamination step, in which the first component and the second component are laminated using a welding material; a joining step, in which the first component and the second component laminated using the welding material are subjected to heat treatment to perform welding joining; an ultrasonic cleaning step, in which the first component and the second component are ultrasonically cleaned before joining; and an ultraviolet irradiation step, in which ultraviolet light is irradiated after the ultrasonic cleaning step; the joint is immersed in isopropanol to extract the organic residues contained in the joint; the UV absorption spectrum of the extract containing the extracted organic residues is measured; the obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less.

[0012] The method for manufacturing the joint according to the present invention includes an ultrasonic cleaning step, in which the first component and the second component described above are ultrasonically cleaned before joining; and an ultraviolet irradiation step, in which ultraviolet light is irradiated after the ultrasonic cleaning step. Therefore, organic residues in the joint can be sufficiently reduced. Then, the aforementioned conjugate can be immersed in isopropanol to extract the organic residues contained therein. The UV absorption spectrum of the extract containing the organic residues is measured. The obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is made to be 4 or less. A conjugate that can suppress problems such as reduced bonding strength caused by organic residues can be manufactured.

[0013] The present invention discloses a method for evaluating organic residues in a joint formed by joining a first component and a second component via a weld layer. The method comprises: an extraction step, in which the joint is immersed in isopropanol to extract organic residues; a UV absorption spectroscopy measurement step, in which the UV absorption spectrum of the extracted organic residue is measured; a standardization step, in which the obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm to 100; an absorbance calculation step, in which the absorbance at a wavelength of 300 nm is calculated from the standardized UV absorption spectrum; and an evaluation step, in which the amount of organic residue in the joint is evaluated by calculating the aforementioned absorbance.

[0014] According to the method for evaluating organic residues in the conjugate of the present invention, the conjugate is immersed in isopropanol to extract the organic residues contained therein. The UV absorption spectrum of the extract containing the extracted organic residues is measured. The obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm as 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is calculated. The amount of organic residues in the conjugate is evaluated by the absorbance at a wavelength of 300 nm. Therefore, the amount of organic residues contained in the conjugate can be evaluated with good accuracy. [Effects of the Invention]

[0015] According to the present invention, in the joint formed by bonding via weld layers, organic residues are sufficiently and reliably reduced. This provides a joint that can suppress problems such as reduced joint strength caused by organic residues, a method for manufacturing the joint, and a method for assessing the amount of organic residues in the joint with good accuracy. Simple Explanation of the Diagram

[0016] []

[0017] [Figure 1] is an explanatory diagram of the assembly of one embodiment of the present invention. [Figure 2] is a flowchart of an organic residue assessment method for a conjugate according to an embodiment of the present invention. [Figure 3] is a flowchart of a method for manufacturing a joint according to an embodiment of the present invention. [Figure 4] is an explanatory diagram of a method for manufacturing a joint according to an embodiment of the present invention. [Figure 5] is an explanatory diagram of the lead shearing evaluation in the embodiment. Implementation

[0018] [Forms of Invention Implementation]

[0019] The following description, with reference to the drawings, describes the assembly, the manufacturing method of the assembly, and the method for evaluating the organic residues of the assembly according to embodiments of the present invention.

[0020] As shown in FIG1, the bonding body 10 of this embodiment is formed by bonding the first component 11 and the second component 12 via a solder layer 13. In this embodiment, the bonding body 10 is a semiconductor device formed by bonding the circuit layer (first component 11) of an insulating circuit board and the semiconductor element (second component 12) via a solder layer 13.

[0021] Here, the circuit layer (first component 11) is made of a metal with excellent conductivity, such as copper or copper alloy, aluminum or aluminum alloy, or iron or iron alloy. In this embodiment, it is made of an iron alloy (Kova alloy). Furthermore, a precious metal film such as Au is preferably formed on the bonding surface of the circuit layer (first component 11). Furthermore, a precious metal film such as Au should preferably be formed on the bonding surface of the semiconductor element (second component 12).

[0022] The welding material constituting the welding layer 13 is appropriately selected based on the material of the joint surfaces of the first component 11 and the second component 12 to be joined. In this embodiment, when the bonding surface of the circuit layer (first component 11) and the bonding surface of the semiconductor element (second component 12) are made of precious metal (Au), Sn-Ag-Cu solder, Au-Sn solder, Sn-Cu solder, etc. can be used as solder materials. In this embodiment, the welding material constituting the welding layer 13 is an Au-Sn solder with a Sn content of 10 mass% to 80 mass% and the remainder being Au and unavoidable impurities.

[0023] Then, in the conjugate 10 of this embodiment, the conjugate 10 is immersed in isopropanol to obtain an extract from which the organic residue of the conjugate 10 is extracted. The UV absorption spectrum of this extract is measured. The obtained UV absorption spectrum is standardized with the absorbance at a wavelength of 207 nm set to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less. As described above, in the conjugate 10 of this embodiment, organic residues are assessed by measuring the UV absorption spectrum of the extract obtained by immersion in isopropanol.

[0024] Hereinafter, the method for assessing organic residues in the conjugate of this embodiment will be described with reference to FIG2.

[0025] (Extraction step S01) By immersing the aforementioned conjugate 10 in isopropanol with a purity of 99.99 vol%, the organic residues contained in the conjugate 10 are extracted into the isopropanol, thereby obtaining an extract containing the extracted organic residues. In addition, the immersion time in extraction step S01 is preferably set within the range of 10 minutes to 60 minutes. Furthermore, in this extraction step S01, it is preferable to apply ultrasound to the impregnated conjugate 10 and isopropanol.

[0026] (UV absorption spectroscopy measurement step S02) Next, the UV absorption spectrum of the obtained extract is measured to obtain the UV absorption spectrum of the extract. The UV absorption spectrum can be obtained using a general spectrometer and the UV absorption detector of an HPLC apparatus. Furthermore, the UV absorption spectrum of isopropanol with a purity of 99.99 vol% (hereinafter referred to as the base solution) without extraction of organic residues was also measured in the same manner as that of the extract to obtain the UV absorption spectrum of the base solution.

[0027] (Standardized Step S03) Secondly, in the UV absorption spectrum of the extract, the absorbance at a wavelength of 207 nm is set to 100, and the absorbance at each wavelength of the UV absorption spectrum is standardized. Similarly, in the UV absorption spectrum of the base liquid, the absorbance at a wavelength of 207 nm is set to 100, and the absorbance at each wavelength of the UV absorption spectrum is standardized.

[0028] (Absorbance calculation step S04) Next, the difference between the normalized absorbance of the extract at a wavelength of 300 nm and the normalized absorbance of the base liquid at a wavelength of 300 nm is calculated, and this difference is taken as the "absorbance at a wavelength of 300 nm (normalized absorbance)".

[0029] (Evaluation Step S05) Secondly, the organic residues of the conjugate 10 were evaluated by the calculated absorbance at a wavelength of 300 nm. In this embodiment, when the absorbance at a wavelength of 300 nm is 4 or less, it is considered that the organic residue has been sufficiently reduced.

[0030] As described above, by assessing the organic residues in the conjugate 10, the amount of organic residues inside or around the conjugate 10 can be accurately assessed. Then, by making the "absorbance at wavelength 300nm" less than 4, the organic residue inside or around the weld layer 13 is sufficiently reduced, thereby improving the bonding strength between the first component 11 and the second component 12. In addition, the absorbance of the conjugate 10 at a wavelength of 300 nm should preferably be 4 or less, and more preferably 1 or less.

[0031] Next, the manufacturing method of the assembly 10 of this embodiment will be described with reference to Figures 3 and 4.

[0032] (S11 step of welding material coating) As shown in Figure 4, welding material 23 is applied to either or both of the mating surfaces of the first component 11 and the second component 12. The application method is not particularly limited and can include, for example, metal masking, screen printing, or dispensing.

[0033] The 23 series of welding materials contain metal powder and flux (solvent, thixotropic agent, activator, resin). The metal powder is Sn-Ag-Cu, Au-Sn, or Sn-Cu as described above; these can be alloy powders or mixed powders. In this embodiment, a mixed powder of Au powder and Sn powder is used.

[0034] The solvents contained in the flux are solvents such as alcohols, ketones, esters, ethers, aromatics, hydrocarbons, terpenes, and terpene-like solvents. Specifically, benzyl alcohol, ethanol, ethyl alcohol, isopropanol, butanol, diethylene glycol, ethylene glycol, ethyl cellosolve, butyl cellosolve, butyl carbitol, isopropanol, 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, hexanediol, cyclohexanediol, 2-terpinenoxyethanol, 2-dihydroterpinenoxyethanol, citral, linalool, limonene, carvacrol, pinene, farnesene, etc., or a mixture thereof can be used.

[0035] As a thixotropic agent, it can be used alone or in combination with other agents such as hardened castor oil, hydrogenated castor oil, carnauba wax, acetamides, hydroxy fatty acids, dibenzylidene sorbitol, bis(p-methylbenzylidene)sorbitol, beeswax, stearamide, hydroxystearylvinylbis(acetamide), etc. As an active agent, it can be added with fatty acids such as adipic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, hydroxy fatty acids such as 1,2-hydroxystearic acid, antioxidants, surfactants, amines, etc. Resins that can be used include, for example, polymerized rosin, natural rosin, purified rosin, etc.

[0036] (Lamination step S12) Secondly, as shown in Figure 4, the first component 11 and the second component 12 are laminated together via the aforementioned welding material 23.

[0037] (Jointing step S13) Next, as shown in Figure 4, the first component 11 and the second component 12, which are laminated by welding material 23, are subjected to heat treatment to form a welding layer 13, thereby joining the first component 11 and the second component 12. Therefore, during heat treatment, the organic components of the flux contained in the welding material 23 will decompose and generate gas.

[0038] In addition, the heating temperature in the joining step S13 is not particularly limited, but should preferably be in the range of 200°C to 300°C. Furthermore, during heat treatment, the laminate can be pressurized in the lamination direction with a pressure of 0 MPa to 0.0007 MPa.

[0039] (Ultrasonic cleaning step S14) Secondly, as shown in Figure 4, the joint 10 is ultrasonically cleaned by immersing the first component 11 and the second component 12, which are joined together by the welding layer 13, in the cleaning solvent 25 and applying ultrasound. Therefore, the cleaning solvent 25 should preferably be warm water (temperature above 50℃ and below 80℃), Pinealpha solution, etc. Furthermore, the optimal duration of ultrasound administration is between 10 and 60 minutes.

[0040] (Ultraviolet irradiation step S15) Secondly, after ultrasonic cleaning and drying, ultraviolet light 30 is applied to the entire surface of the joint 10, including the weld layer 13, to the first component 11 and the second component 12 joined together by the weld layer 13. The wavelength of the ultraviolet light 30 is preferably between 160 nm and 175 nm; the illuminance is preferably between 100 mW / cm² and 150 mW / cm². By using the ultrasonic cleaning step S14 and the ultraviolet irradiation step S15 described above, the organic residues in the conjugate 10 are reduced, and the absorbance of the conjugate 10 at a wavelength of 300 nm is reduced to 4 or less. In addition, the exposure time to ultraviolet 30 should be set within the range of 5 to 60 minutes.

[0041] By employing the above-mentioned steps of coating solder S11, lamination S12, bonding S13, ultrasonic cleaning S14, and ultraviolet irradiation S15, the bonded body 10 of this embodiment is manufactured.

[0042] According to the assembly 10 of this embodiment as described above, since the organic residue contained in the assembly 10 is extracted by immersing the assembly 10 in isopropanol, and the UV absorption spectrum of the extracted organic residue is measured, the amount of organic residue contained in the assembly 10 can be accurately assessed. Then, the obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm to 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is limited to 4 or less. Therefore, the amount of organic residue contained in the joint 10 is sufficiently reduced, and problems such as reduced bonding strength caused by organic residue can be suppressed.

[0043] Furthermore, the manufacturing method of the joint 10 according to this embodiment includes an ultrasonic cleaning step S14, in which the first component 11 and the second component 12 joined by the welding layer 13 are ultrasonically cleaned; and an ultraviolet irradiation step S15, in which the first component 11 and the second component 12 joined by the welding layer 13 are irradiated with ultraviolet light 30 after the ultrasonic cleaning step S14. Therefore, organic residues in the joint 10 can be sufficiently reduced. Therefore, the absorbance of the joint 10 at a wavelength of 300 nm can be reduced to 4 or less, and the joint 10 can be manufactured to suppress problems such as reduced bonding strength caused by organic residues.

[0044] Furthermore, the method for evaluating organic residues in the conjugate 10 according to this embodiment, as shown in Figure 2, includes: an extraction step S01, in which the conjugate 10 is immersed in isopropanol to extract the organic residues from the conjugate; a UV absorption spectroscopy measurement step S02, in which the UV absorption spectrum of the extracted organic residue is measured; a standardization step S03, in which the obtained UV absorption spectrum is standardized by setting the absorbance at a wavelength of 207 nm to 100; an absorbance calculation step S04, in which the absorbance at a wavelength of 300 nm is calculated from the standardized UV absorption spectrum; and an evaluation step S05, in which the amount of organic residues in the conjugate is evaluated based on the calculated absorbance at a wavelength of 300 nm. Therefore, the amount of organic residues contained in the conjugate 10 can be evaluated with good accuracy.

[0045] The embodiments of the present invention have been described above, but the present invention is not limited thereto, and appropriate changes may be made without departing from the technical concept of the present invention. [Example]

[0046] The following describes the results of the verification experiments conducted to confirm the effectiveness of the present invention.

[0047] A substrate is prepared to form a nickel plating layer (0.5~1.0μm thick) as a base layer on the surface of an iron alloy (Kova alloy) plate (250mm×150mm×0.1mm thick) as the first component, and to form a gold plating layer (0.05μm thick) on this nickel plating layer. As the second component, a virtual wafer (1mm×1mm×0.04mm thick) with a gold plating layer (0.05 μm thick) applied to the bonding surface is prepared.

[0048] Furthermore, prepare the soldering materials containing metal powder and flux as shown in Table 1. In addition, the flux used contains 52 mass% diethylene glycol monohexyl ether as a solvent, 5 mass% cured castor oil as a thixotropic agent, 3 mass% adipic acid as a thixotropic agent, and 40 mass% polymerized rosin as a resin.

[0049] The welding material is applied to the joint surface of the first component with a coating thickness of 200 μm, and the second component is then laminated with the welding material. The composite was subjected to heat treatment under nitrogen atmosphere under the conditions shown in Table 1, and the first component and the second component were joined together via a welding layer.

[0050] Then, after joining, ultrasonic cleaning was performed on Examples 1-5 and Comparative Example 1 of the present invention under the conditions shown in Table 1. In contrast, ultrasonic cleaning was not performed on Comparative Examples 2 and 3. Furthermore, in Examples 1-5 and Comparative Examples 1-3 of the present invention, ultraviolet light was irradiated under the conditions shown in Table 1. Here, the ultraviolet light was irradiated with a wavelength of 172 nm and an illuminance of 140 mW / cm², irradiating the entire conjugate. For the joint obtained as described above, the absorbance is calculated and the lead shear is evaluated as follows.

[0051] (Absorbance) The obtained conjugate was placed in a screw-cap vial (50 mL capacity), and 2 mL of isopropanol (purity: 99.99 vol%) was added to the vial. Ultrasound was applied for 5 minutes (device: SHARP, model: UC-6200, ultrasound intensity setting: level 5 of the aforementioned device's 5-level settings), extracting the organic residues contained in the conjugate (total immersion time in isopropanol: 7 minutes). The conjugate was then removed to obtain the extract. Without loading a column into the HPLC apparatus (Shimadzu Corporation HPLC Prominence), 5 μL of extract was injected, and the UV absorption spectrum of the extract was measured using the UV absorption spectrometer (SPD-20) included with the HPLC apparatus. Isopropanol was used as the mobile phase, and the flow rate was 0.1 mL / min (3 min) → 1.0 mL / min (5 min). In addition, the UV absorption spectrum of isopropanol with a purity of 99.99 vol% without extraction of organic residues was also measured, and the UV absorption spectrum of the base solution was also measured.

[0052] In the UV absorption spectrum of the extract, the absorbance at wavelength 207 nm is set to 100, and the absorbance at each wavelength of the UV absorption spectrum is normalized. Similarly, in the UV absorption spectrum of the base liquid, the absorbance at wavelength 207 nm is also set to 100, and the absorbance at each wavelength of the UV absorption spectrum is normalized. Then, the difference in absorbance between the extract and the base liquid was calculated from the normalized absorbance at a wavelength of 300 nm, and recorded as "absorbance" in Table 1.

[0053] (Lead wire shearing evaluation) The virtual wafer surface and the substrate surface (first component surface) of the resulting bond are subjected to gold wire bonding. The bonding point on the substrate surface (first component surface) is set at a distance of 500 μm from the bonding end between the virtual wafer and the substrate, and from the opposite side of the virtual wafer. The gold wire used is 99.99% pure and 25μm in diameter. The bonding conditions are: bonding temperature 250℃, applied pressure 0.6N, and the output power of the electric torch is set to supply a ball with a diameter of 50μm. The ultrasonic application time is set to 10ms.

[0054] Then, the bonding strength of the leads was evaluated by a shear test. As shown in Figure 5, a lateral force was applied to the lead ball to break it. A force greater than 170 mN when the bond between the lead ball and the substrate was broken was rated "A", a force greater than 150 mN but less than 170 mN was rated "B", and a force less than 150 mN was rated "C".

[0055]

[0056] In Comparative Example 1, Sn-Ag-Cu solder was used for bonding, and ultrasonic cleaning and ultraviolet irradiation were performed. However, the absorbance at 300 nm was 5.0, and the lead shear assessment was "C". It is speculated that this was due to insufficient reduction of organic residues, which led to insufficient bonding strength of the leads.

[0057] In Comparative Example 2, Au-Sn based solder was used for bonding. Ultrasonic cleaning was not performed, but ultraviolet irradiation was applied. However, the absorbance at 300 nm was 12.0, and the lead shear assessment was "C". It is speculated that this was due to insufficient reduction of organic residues, which resulted in insufficient bonding strength of the leads.

[0058] In Comparative Example 3, Sn-Cu solder was used for bonding. Ultrasonic cleaning was not performed, but ultraviolet irradiation was applied. However, the absorbance at 300 nm was 15.0, and the lead shear assessment was "C". It is speculated that this was due to insufficient reduction of organic residues, which led to insufficient bonding strength of the leads.

[0059] In contrast, in Example 1 of this invention, Sn-Ag-Cu solder was used for bonding, and ultrasonic cleaning and ultraviolet irradiation were performed. The absorbance at a wavelength of 300 nm was 0.5, and the lead shear evaluation was "A". In Examples 2 and 3 of this invention, Au-Sn solder was used for bonding, and ultrasonic cleaning and ultraviolet irradiation were performed. The absorbance at a wavelength of 300 nm was 0.5, and the lead shear evaluation was "A".

[0060] In Example 4 of this invention, Sn-Cu solder was used for bonding, and ultrasonic cleaning and ultraviolet irradiation were performed. The absorbance at a wavelength of 300 nm was 0.9, and the lead shear evaluation was "A". In Example 5 of this invention, Sn-Cu solder was used for bonding, and ultrasonic cleaning and ultraviolet irradiation were performed. The absorbance at a wavelength of 300 nm was 3.8, and the lead shear evaluation was "B".

[0061] Based on the results of the above confirmation experiments, according to the present invention, a joint in which organic residues are sufficiently and reliably reduced in a joint formed by bonding via a weld layer, a method for manufacturing the joint, and an organic residue assessment method for the joint that can accurately assess the amount of organic residues are provided. [Industry-level availability]

[0062] According to the present invention, in the joint formed by bonding via weld layers, organic residues are sufficiently and reliably reduced. This provides a joint that can suppress problems such as reduced joint strength caused by organic residues, a method for manufacturing the joint, and a method for assessing the amount of organic residues in the joint with good accuracy. Therefore, it is industrially applicable.

[0063] []

[0064] 10: Joint 11: First component 12: Second component 13: Weld layer 23: Welding materials 30: Ultraviolet rays

Claims

1. A joint body formed by joining a first component and a second component via a welding layer, characterized in that the joint body is immersed in isopropanol to extract organic residues contained therein, the UV absorption spectrum of the extract from which the organic residues are extracted is measured, the obtained UV absorption spectrum is standardized with absorbance at a wavelength of 207 nm as 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less.

2. A method for manufacturing a joint, comprising a first component and a second component joined by a welding layer, characterized by comprising: a lamination step, wherein the first component and the second component are laminated by a welding material; a joining step, wherein the first component and the second component laminated by the welding material are subjected to heat treatment to perform welding joining; an ultrasonic cleaning step, wherein the first component and the second component are ultrasonically cleaned before joining; and an ultraviolet irradiation step, wherein after the ultrasonic cleaning step, ultraviolet light is irradiated, the joint is immersed in isopropanol to extract the organic residue contained in the joint, the UV absorption spectrum of the extract containing the organic residue is measured, the obtained UV absorption spectrum is standardized with absorbance at a wavelength of 207 nm as 100, and the absorbance at a wavelength of 300 nm obtained from the standardized UV absorption spectrum is 4 or less.

3. A method for evaluating organic residues in a joint, wherein the joint is formed by joining a first component and a second component via a weld layer, characterized by comprising: an extraction step, wherein the joint is immersed in isopropanol to extract organic residues from the joint; a UV absorption spectroscopy measurement step, wherein the UV absorption spectrum of the extracted organic residue is measured; a standardization step, wherein the obtained UV absorption spectrum is standardized with absorbance at a wavelength of 207 nm as 100; an absorbance calculation step, wherein the absorbance at a wavelength of 300 nm is calculated from the standardized UV absorption spectrum; and an evaluation step, wherein the amount of organic residues in the joint is evaluated by calculating the aforementioned absorbance.

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