Purpose This paper aims to propose a deep learning model that can be used to expand the number of samples. In the process of manufacturing and assembling electronic components on the printed circuit board in the surface mount technology production line, it is relatively easy to collect non-defective samples, but it is difficult to collect defective samples within a certain period of time. Therefore, the number of non-defective components is much greater than the number of defective components. In the process of training the defect detection method of electronic components based on deep learning, a large number of defective and non-defective samples need to be input at the same time. Design/methodology/approach To obtain enough electronic components samples required for training, a method based on the generative adversarial network (GAN) to generate training samples is proposed, and then the generated samples and real samples are used to train the convolutional neural networks (CNN) together to obtain the best detection results. Findings The experimental results show that the defect recognition method using GAN and CNN can not only expand the sample images of the electronic components required for the training model but also accurately classify the defect types. Originality/value To solve the problem of unbalanced sample types in component inspection, a GAN-based method is proposed to generate different types of training component samples and then the generated samples and real samples are used to train the CNN together to obtain the best detection results.
{"title":"Electronic component detection based on image sample generation","authors":"Hao Wu, Quanquan Lv, Jian Yang, Xiaodong Yan, Xiangrong Xu","doi":"10.1108/SSMT-08-2020-0036","DOIUrl":"https://doi.org/10.1108/SSMT-08-2020-0036","url":null,"abstract":"\u0000Purpose\u0000This paper aims to propose a deep learning model that can be used to expand the number of samples. In the process of manufacturing and assembling electronic components on the printed circuit board in the surface mount technology production line, it is relatively easy to collect non-defective samples, but it is difficult to collect defective samples within a certain period of time. Therefore, the number of non-defective components is much greater than the number of defective components. In the process of training the defect detection method of electronic components based on deep learning, a large number of defective and non-defective samples need to be input at the same time.\u0000\u0000\u0000Design/methodology/approach\u0000To obtain enough electronic components samples required for training, a method based on the generative adversarial network (GAN) to generate training samples is proposed, and then the generated samples and real samples are used to train the convolutional neural networks (CNN) together to obtain the best detection results.\u0000\u0000\u0000Findings\u0000The experimental results show that the defect recognition method using GAN and CNN can not only expand the sample images of the electronic components required for the training model but also accurately classify the defect types.\u0000\u0000\u0000Originality/value\u0000To solve the problem of unbalanced sample types in component inspection, a GAN-based method is proposed to generate different types of training component samples and then the generated samples and real samples are used to train the CNN together to obtain the best detection results.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49041898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-20DOI: 10.1108/SSMT-10-2020-0042
Fei Chong Ng, M. A. Abas
Purpose This paper aims to present new analytical model for the filling times prediction in flip-chip underfill encapsulation process that is based on the surface energetic for post-bump flow. Design/methodology/approach The current model was formulated based on the modified regional segregation approach that consists of bump and post-bump regions. Both the expansion flow and the subsequent bumpless flow as integrated in the post-bump region were modelled considering the surface energy–work balance. Findings Upon validated with the past underfill experiment, the current model has the lowest root mean square deviation of 4.94 s and maximum individual deviation of 26.07%, upon compared to the six other past analytical models. Additionally, the current analytically predicted flow isolines at post-bump region are in line with the experimental observation. Furthermore, the current analytical filling times in post-bump region are in better consensus with the experimental times as compared to the previous model. Therefore, this model is regarded as an improvised version of the past filling time models. Practical implications The proposed analytical model enables the filling time determination for flip-chip underfill process at higher accuracy, while providing more precise and realistic post-bump flow visualization. This model could benefit the future underfill process enhancement and package design optimization works, to resolve the productivity issue of prolonged filling process. Originality/value The analytical underfill studies are scarce, with only seven independent analytical filling time models being developed to date. In particular, the expansion flow of detachment jump was being considered in only two previous works. Nonetheless, to the best of the authors’ knowledge, there is no analytical model that considered the surface energies during the underfill flow or based on its energy–work balance. Instead, the previous modelling on post-bump flow was based on either kinematic or geometrical that is coupled with major assumptions.
{"title":"Surface energetic-based analytical filling time model for flip-chip underfill process","authors":"Fei Chong Ng, M. A. Abas","doi":"10.1108/SSMT-10-2020-0042","DOIUrl":"https://doi.org/10.1108/SSMT-10-2020-0042","url":null,"abstract":"\u0000Purpose\u0000This paper aims to present new analytical model for the filling times prediction in flip-chip underfill encapsulation process that is based on the surface energetic for post-bump flow.\u0000\u0000\u0000Design/methodology/approach\u0000The current model was formulated based on the modified regional segregation approach that consists of bump and post-bump regions. Both the expansion flow and the subsequent bumpless flow as integrated in the post-bump region were modelled considering the surface energy–work balance.\u0000\u0000\u0000Findings\u0000Upon validated with the past underfill experiment, the current model has the lowest root mean square deviation of 4.94 s and maximum individual deviation of 26.07%, upon compared to the six other past analytical models. Additionally, the current analytically predicted flow isolines at post-bump region are in line with the experimental observation. Furthermore, the current analytical filling times in post-bump region are in better consensus with the experimental times as compared to the previous model. Therefore, this model is regarded as an improvised version of the past filling time models.\u0000\u0000\u0000Practical implications\u0000The proposed analytical model enables the filling time determination for flip-chip underfill process at higher accuracy, while providing more precise and realistic post-bump flow visualization. This model could benefit the future underfill process enhancement and package design optimization works, to resolve the productivity issue of prolonged filling process.\u0000\u0000\u0000Originality/value\u0000The analytical underfill studies are scarce, with only seven independent analytical filling time models being developed to date. In particular, the expansion flow of detachment jump was being considered in only two previous works. Nonetheless, to the best of the authors’ knowledge, there is no analytical model that considered the surface energies during the underfill flow or based on its energy–work balance. Instead, the previous modelling on post-bump flow was based on either kinematic or geometrical that is coupled with major assumptions.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44580631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-17DOI: 10.1108/ssmt-05-2020-0023
Guangyuan Ren, M. Collins
This paper aims to investigate the creep behaviour of the recently developed Sn–8Zn–3Bi–xSb (x = 0, 0.5, 1.0 and 1.5) low temperature lead-free solder alloys.,An in-house compressive test rig was developed to perform creep tests under stresses of 20–40 MPa and temperature range 25°C–75 °C. Dorn power law and Garofalo hyperbolic sine law were used to model the secondary creep rate.,High coefficient of determination R2 of 0.99 is achieved for both the models. It was found that the activation energy of Sn–8Zn–3Bi solder alloy can be significantly increased with addition of Sb, by 60% to 90 kJ/mol approximately, whereas the secondary creep exponent falls in the range 3–7. Improved creep resistance is attributed to solid solution strengthening introduced by micro-alloying. Creep mechanisms that govern the deformation of these newly developed lead-free solder alloys have also been proposed.,The findings are expected to fill the gap of knowledge on creep behaviour of these newly developed solder alloys, which are possible alternatives as lead-free interconnecting material in low temperature electronic assembly.
{"title":"Effect of Sb additions on the creep behaviour of low temperature lead-free Sn–8Zn–3Bi solder alloy","authors":"Guangyuan Ren, M. Collins","doi":"10.1108/ssmt-05-2020-0023","DOIUrl":"https://doi.org/10.1108/ssmt-05-2020-0023","url":null,"abstract":"This paper aims to investigate the creep behaviour of the recently developed Sn–8Zn–3Bi–xSb (x = 0, 0.5, 1.0 and 1.5) low temperature lead-free solder alloys.,An in-house compressive test rig was developed to perform creep tests under stresses of 20–40 MPa and temperature range 25°C–75 °C. Dorn power law and Garofalo hyperbolic sine law were used to model the secondary creep rate.,High coefficient of determination R2 of 0.99 is achieved for both the models. It was found that the activation energy of Sn–8Zn–3Bi solder alloy can be significantly increased with addition of Sb, by 60% to 90 kJ/mol approximately, whereas the secondary creep exponent falls in the range 3–7. Improved creep resistance is attributed to solid solution strengthening introduced by micro-alloying. Creep mechanisms that govern the deformation of these newly developed lead-free solder alloys have also been proposed.,The findings are expected to fill the gap of knowledge on creep behaviour of these newly developed solder alloys, which are possible alternatives as lead-free interconnecting material in low temperature electronic assembly.","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":"33 1","pages":"159-169"},"PeriodicalIF":2.0,"publicationDate":"2021-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1108/ssmt-05-2020-0023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44683106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-14DOI: 10.1108/SSMT-10-2020-0047
F. Sun, Zhenya Pan, Yang Liu, Xiang Li, Haoyu Liu, Wenpeng Li
Purpose The purpose of this paper is to quickly manufacture full Cu3Sn-microporous copper composite joints for high-temperature power electronics applications and study the microstructure evolution and the shear strength of Cu3Sn at different bonding times. Design/methodology/approach In this paper, a novel structure of Cu/composite solder sheet/Cu was designed. The composite solder sheet was made of microporous copper filled with Sn. The composite joint was bonded by thermo-compression bonding under pressure of 0.6 MPa at 300°C. The microstructure evolution and the growth behavior of Cu3Sn at different bonding times were observed by electron microscope and metallographic microscope. The shear strength of the joint was measured by shear machine. Findings At initial bonding stage the copper atoms in the substrate and the copper atoms in the microporous copper dissolved into the liquid Sn. Then the scallop-liked Cu6Sn5 phases formed at the interface of liquid Sn/microporous copper and liquid Sn/Cu substrates. During the liquid Sn changing to Cu6Sn5 phases, Cu3Sn phases formed and grew at the interface of Cu6Sn5/Cu substrates and Cu6Sn5/microporous copper. After that the Cu3Sn phases continued to grow and the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained. The growth rule of Cu3Sn was parabolic growth. The shear strength of the composite joints was about 155 MPa. Originality/value This paper presents a novel full Cu3Sn-microporous copper composite joint with high shear strength for high-temperature applications based on transient liquid phase bonding. The microstructure evolution and the growth behavior of Cu3Sn in the composite joints were studied. The shear strength and the fracture mechanism of the composite joints were studied.
{"title":"Microstructure evolution and shear strength of full Cu3Sn- microporous copper composite joint by thermo-compression bonding","authors":"F. Sun, Zhenya Pan, Yang Liu, Xiang Li, Haoyu Liu, Wenpeng Li","doi":"10.1108/SSMT-10-2020-0047","DOIUrl":"https://doi.org/10.1108/SSMT-10-2020-0047","url":null,"abstract":"\u0000Purpose\u0000The purpose of this paper is to quickly manufacture full Cu3Sn-microporous copper composite joints for high-temperature power electronics applications and study the microstructure evolution and the shear strength of Cu3Sn at different bonding times.\u0000\u0000\u0000Design/methodology/approach\u0000In this paper, a novel structure of Cu/composite solder sheet/Cu was designed. The composite solder sheet was made of microporous copper filled with Sn. The composite joint was bonded by thermo-compression bonding under pressure of 0.6 MPa at 300°C. The microstructure evolution and the growth behavior of Cu3Sn at different bonding times were observed by electron microscope and metallographic microscope. The shear strength of the joint was measured by shear machine.\u0000\u0000\u0000Findings\u0000At initial bonding stage the copper atoms in the substrate and the copper atoms in the microporous copper dissolved into the liquid Sn. Then the scallop-liked Cu6Sn5 phases formed at the interface of liquid Sn/microporous copper and liquid Sn/Cu substrates. During the liquid Sn changing to Cu6Sn5 phases, Cu3Sn phases formed and grew at the interface of Cu6Sn5/Cu substrates and Cu6Sn5/microporous copper. After that the Cu3Sn phases continued to grow and the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained. The growth rule of Cu3Sn was parabolic growth. The shear strength of the composite joints was about 155 MPa.\u0000\u0000\u0000Originality/value\u0000This paper presents a novel full Cu3Sn-microporous copper composite joint with high shear strength for high-temperature applications based on transient liquid phase bonding. The microstructure evolution and the growth behavior of Cu3Sn in the composite joints were studied. The shear strength and the fracture mechanism of the composite joints were studied.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42900189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-13DOI: 10.1108/SSMT-10-2020-0048
G. Mårtensson, Johan Göhl, Andreas Mark
{"title":"Simulation of jet printing of solder paste for surface mounted technology","authors":"G. Mårtensson, Johan Göhl, Andreas Mark","doi":"10.1108/SSMT-10-2020-0048","DOIUrl":"https://doi.org/10.1108/SSMT-10-2020-0048","url":null,"abstract":"","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47074791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-08DOI: 10.1108/SSMT-10-2020-0040
M. E. Raypah, M. Devarajan, S. Mahmud
Purpose One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting diode (LED) package is linked to the external thermal management that includes a selection of the cooling mode, design of heatsink/substrate and thermal interface material (TIM). Among the significant factors that increase the light output of the of the LED system are efficient substrate and TIM. In this work, the influence of TIM on the luminous flux performance of commercial indium gallium aluminium phosphide (InGaAlP) low-power (LP) LEDs was investigated. Design/methodology/approach One batch of LEDs was mounted directly onto substrates which were glass-reinforced epoxy (FR4) and aluminium-based metal-core printed circuit boards (MCPCBs) with a dielectric layer of different thermal conductivities. Another batch of LEDs was prepared in a similar way, but a layer of TIM was embedded between the LED package and substrate. The TIMs were thermally conductive epoxy (TCE) and thermally conductive adhesive (TCA). The LED parameters were measured by using the integrated system of thermal transient tester (T3Ster) and thermal-radiometric characterization of LEDs at various input currents. Findings With the employment of TIM, the authors found that the LED’s maximum luminous flux was significantly higher than the value mentioned in the LED datasheet, and that a significant reduction in thermal resistance and junction temperature was revealed. The results showed that for a system with low thermal resistance, the maximum luminous flux appeared to occur at a higher power level. It was found that the maximum luminous flux was 24.10, 28.40 and 36.00 lm for the LEDs mounted on the FR4 and two MCPCBs, respectively. After TCA application on the LEDs, the maximum luminous flux values were 32.70, 36.60 and 37.60 lm for the FR4 and MCPCBs, respectively. Moreover, the findings demonstrated that the performance of the LED mounted on the FR4 substrate was more affected by the employment of the TIM than that of MCPCBs. Research limitations/implications One of the major problems in the lighting industry is the thermal management of the device. In many low-power LED applications, the air gap between the two solder pads is not filled up. Heat flow is restricted by the air gap leading to thermal build-up and higher thermal resistance resulting in lower maximum luminous flux. Among the significant factors that increase the light output of the LED system are efficient substrate and TIM. Practical implications The findings in this work can be used as a method to improve thermal management of LP LEDs by applying thermal interface materials that can offer more efficient and brighter LP LEDs. Using aluminium-based substrates can also offer similar benefits. Social implications Users of LP LEDs can benefit from the findings in this work. Brighter automotive lighting (signalling and backlighti
{"title":"Impact of thermal interface material on luminous flux curve of InGaAlP low-power light-emitting diodes","authors":"M. E. Raypah, M. Devarajan, S. Mahmud","doi":"10.1108/SSMT-10-2020-0040","DOIUrl":"https://doi.org/10.1108/SSMT-10-2020-0040","url":null,"abstract":"\u0000Purpose\u0000One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting diode (LED) package is linked to the external thermal management that includes a selection of the cooling mode, design of heatsink/substrate and thermal interface material (TIM). Among the significant factors that increase the light output of the of the LED system are efficient substrate and TIM. In this work, the influence of TIM on the luminous flux performance of commercial indium gallium aluminium phosphide (InGaAlP) low-power (LP) LEDs was investigated.\u0000\u0000\u0000Design/methodology/approach\u0000One batch of LEDs was mounted directly onto substrates which were glass-reinforced epoxy (FR4) and aluminium-based metal-core printed circuit boards (MCPCBs) with a dielectric layer of different thermal conductivities. Another batch of LEDs was prepared in a similar way, but a layer of TIM was embedded between the LED package and substrate. The TIMs were thermally conductive epoxy (TCE) and thermally conductive adhesive (TCA). The LED parameters were measured by using the integrated system of thermal transient tester (T3Ster) and thermal-radiometric characterization of LEDs at various input currents.\u0000\u0000\u0000Findings\u0000With the employment of TIM, the authors found that the LED’s maximum luminous flux was significantly higher than the value mentioned in the LED datasheet, and that a significant reduction in thermal resistance and junction temperature was revealed. The results showed that for a system with low thermal resistance, the maximum luminous flux appeared to occur at a higher power level. It was found that the maximum luminous flux was 24.10, 28.40 and 36.00 lm for the LEDs mounted on the FR4 and two MCPCBs, respectively. After TCA application on the LEDs, the maximum luminous flux values were 32.70, 36.60 and 37.60 lm for the FR4 and MCPCBs, respectively. Moreover, the findings demonstrated that the performance of the LED mounted on the FR4 substrate was more affected by the employment of the TIM than that of MCPCBs.\u0000\u0000\u0000Research limitations/implications\u0000One of the major problems in the lighting industry is the thermal management of the device. In many low-power LED applications, the air gap between the two solder pads is not filled up. Heat flow is restricted by the air gap leading to thermal build-up and higher thermal resistance resulting in lower maximum luminous flux. Among the significant factors that increase the light output of the LED system are efficient substrate and TIM.\u0000\u0000\u0000Practical implications\u0000The findings in this work can be used as a method to improve thermal management of LP LEDs by applying thermal interface materials that can offer more efficient and brighter LP LEDs. Using aluminium-based substrates can also offer similar benefits.\u0000\u0000\u0000Social implications\u0000Users of LP LEDs can benefit from the findings in this work. Brighter automotive lighting (signalling and backlighti","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44177647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.1108/SSMT-07-2020-0029
W. Siswanto, K. Borodin, Z. Mahmoud, A. Surendar, S. Sajjadifar, G. Abdilova, Jun Chang
Purpose The purpose of this study is to investigate the effect of aging temperature on the barrel-type solder joint lifetime of electronic devices and to include these effects in the modified prediction model. Design/methodology/approach Several accelerated shear stress tests under different stress amplitudes and aging temperatures were performed. Findings It was found that by aging temperature increasing, the lifetime decreases. Morrow energy model was also found as the best prediction model when the aging temperature is taken into consideration. Originality value It is confirmed.
{"title":"Role of aging temperature on thermomechanical fatigue lifetime of solder joints in electronic systems","authors":"W. Siswanto, K. Borodin, Z. Mahmoud, A. Surendar, S. Sajjadifar, G. Abdilova, Jun Chang","doi":"10.1108/SSMT-07-2020-0029","DOIUrl":"https://doi.org/10.1108/SSMT-07-2020-0029","url":null,"abstract":"\u0000Purpose\u0000The purpose of this study is to investigate the effect of aging temperature on the barrel-type solder joint lifetime of electronic devices and to include these effects in the modified prediction model.\u0000\u0000\u0000Design/methodology/approach\u0000Several accelerated shear stress tests under different stress amplitudes and aging temperatures were performed.\u0000\u0000\u0000Findings\u0000It was found that by aging temperature increasing, the lifetime decreases. Morrow energy model was also found as the best prediction model when the aging temperature is taken into consideration.\u0000\u0000\u0000Originality value\u0000It is confirmed.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47089963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-15DOI: 10.1108/SSMT-10-2020-0046
Chung-Yung Lin
Purpose This paper aims to derive a model of growth kinetics of the intermetallic compound (IMC) layer formed in the reaction between liquid Sn-based solders and Ni particle reinforcements and to compare with the experimental data to verify the effects of Sn concentration and alloying element. Design/methodology/approach A composite solder was manufactured by mechanically introducing Ni particle reinforcements into a solder matrix. The effect of the non-reactive alloying elements, Ag, Pb and Bi, on the growth kinetics of the IMC formed between liquid Sn-based eutectic solders and Ni particles, reacting this composite solder at 250°C–280°C was studied. Findings Experimental results showed that only the IMC Ni3Sn4 was present as a reaction product. Using the diffusion-controlled reaction mechanism, a kinetic equation quantifying both Sn concentration and alloying element effects was derived and verified by comparing the kinetic data obtained using four different solders with different concentrations of Sn and the alloying elements. Originality/value The similarity between the activation energies of these four solders confirms that the diffusion of Sn atoms through the IMC is the rate-controlling step. Besides, the kinetic values are independent of the geometry of Ni, whether spherical particle or flat substrate.
{"title":"Interfacial reaction between Ni particle reinforcements and liquid Sn-based eutectic solders","authors":"Chung-Yung Lin","doi":"10.1108/SSMT-10-2020-0046","DOIUrl":"https://doi.org/10.1108/SSMT-10-2020-0046","url":null,"abstract":"\u0000Purpose\u0000This paper aims to derive a model of growth kinetics of the intermetallic compound (IMC) layer formed in the reaction between liquid Sn-based solders and Ni particle reinforcements and to compare with the experimental data to verify the effects of Sn concentration and alloying element.\u0000\u0000\u0000Design/methodology/approach\u0000A composite solder was manufactured by mechanically introducing Ni particle reinforcements into a solder matrix. The effect of the non-reactive alloying elements, Ag, Pb and Bi, on the growth kinetics of the IMC formed between liquid Sn-based eutectic solders and Ni particles, reacting this composite solder at 250°C–280°C was studied.\u0000\u0000\u0000Findings\u0000Experimental results showed that only the IMC Ni3Sn4 was present as a reaction product. Using the diffusion-controlled reaction mechanism, a kinetic equation quantifying both Sn concentration and alloying element effects was derived and verified by comparing the kinetic data obtained using four different solders with different concentrations of Sn and the alloying elements.\u0000\u0000\u0000Originality/value\u0000The similarity between the activation energies of these four solders confirms that the diffusion of Sn atoms through the IMC is the rate-controlling step. Besides, the kinetic values are independent of the geometry of Ni, whether spherical particle or flat substrate.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":"1 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41860427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-08DOI: 10.1108/SSMT-07-2020-0033
M. Ekpu
Purpose In microelectronics industry, the reliability of its components is a major area of concern for engineers. Therefore, it is imperative that such concerns are addressed by using the most reliable materials available. Thermal interface materials (TIMs) are used in electronic devices to bridge the topologies that exists between a heat sink and the flip chip assembly. Therefore, this study aims to investigate the reliability of SAC405 and SAC396 in a microelectronics assembly. Design/methodology/approach In this paper, SnAgCu solder alloys (SAC405 and SAC396) were used as the TIMs. The model, which comprises the chip, TIM and heat sink base, was developed with ANSYS finite element analysis software and simulated under a thermal cycling load of between −40°C and 85°C. Findings The results obtained from this paper were based on the total deformation, stress, strain and fatigue life of the lead-free solder materials. The analyses of the results showed that SAC405 is more reliable than SAC396. This was evident in the fatigue life analysis where it was predicted that it took about 85 days for SAC405 to fail, whereas it took about 13 days for SAC396 to fail. Therefore, SAC405 is recommended as the TIM of choice compared to SAC396 based upon the findings of this investigation. Originality/value This paper is centred on SnAgCu solders used as TIMs. This paper demonstrated that SAC405 is a reliable solder TIM. This can guide manufacturers of electronic products in deciding which SAC solder to apply as TIM during the assembly process.
{"title":"Reliability analysis of SnAgCu lead-free solder thermal interface materials in microelectronics","authors":"M. Ekpu","doi":"10.1108/SSMT-07-2020-0033","DOIUrl":"https://doi.org/10.1108/SSMT-07-2020-0033","url":null,"abstract":"\u0000Purpose\u0000In microelectronics industry, the reliability of its components is a major area of concern for engineers. Therefore, it is imperative that such concerns are addressed by using the most reliable materials available. Thermal interface materials (TIMs) are used in electronic devices to bridge the topologies that exists between a heat sink and the flip chip assembly. Therefore, this study aims to investigate the reliability of SAC405 and SAC396 in a microelectronics assembly.\u0000\u0000\u0000Design/methodology/approach\u0000In this paper, SnAgCu solder alloys (SAC405 and SAC396) were used as the TIMs. The model, which comprises the chip, TIM and heat sink base, was developed with ANSYS finite element analysis software and simulated under a thermal cycling load of between −40°C and 85°C.\u0000\u0000\u0000Findings\u0000The results obtained from this paper were based on the total deformation, stress, strain and fatigue life of the lead-free solder materials. The analyses of the results showed that SAC405 is more reliable than SAC396. This was evident in the fatigue life analysis where it was predicted that it took about 85 days for SAC405 to fail, whereas it took about 13 days for SAC396 to fail. Therefore, SAC405 is recommended as the TIM of choice compared to SAC396 based upon the findings of this investigation.\u0000\u0000\u0000Originality/value\u0000This paper is centred on SnAgCu solders used as TIMs. This paper demonstrated that SAC405 is a reliable solder TIM. This can guide manufacturers of electronic products in deciding which SAC solder to apply as TIM during the assembly process.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47167121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-25DOI: 10.1108/SSMT-06-2020-0026
Xu Han, Xiaoyan Li, P. Yao, Dalong Chen
Purpose This study aims to investigate the interfacial microstructures of ultrasonic-assisted solder joints at different soldering times. Design/methodology/approach Solder joints with different microstructures are obtained by ultrasonic-assisted soldering. To analyze the effect of ultrasounds on Cu6Sn5 growth during the solid–liquid reaction stage, the interconnection heights of solder joints are increased from 30 to 50 μm. Findings Scallop-like Cu6Sn5 nucleate and grow along the Cu6Sn5/Cu3Sn interface under the traditional soldering process. By comparison, some Cu6Sn5 are formed at Cu6Sn5/Cu3Sn interface and some Cu6Sn5 are randomly distributed in Sn when ultrasonic-assisted soldering process is used. The reason for the formation of non-interfacial Cu6Sn5 has to do with the shock waves and micro-jets produced by ultrasonic treatment, which leads to separation of some Cu6Sn5 from the interfacial Cu6Sn5 to form non-interfacial Cu6Sn5. The local high pressure generated by the ultrasounds promotes the heterogeneous nucleation and growth of Cu6Sn5. Also, some branch-like Cu3Sn formed at Cu6Sn5/Cu3Sn interface render the interfacial Cu3Sn in ultrasonic-assisted solder joints present a different morphology from the wave-like or planar-like Cu3Sn in conventional soldering joints. Meanwhile, some non-interfacial Cu3Sn are present in non-interfacial Cu6Sn5 due to reaction of Cu atoms in liquid Sn with non-interfacial Cu6Sn5 to form non-interfacial Cu3Sn. Overall, full Cu3Sn solder joints are obtained at ultrasonic times of 60 s. Originality/value The obtained microstructure evolutions of ultrasonic-assisted solder joints in this paper are different from those reported in previous studies. Based on these differences, the effects of ultrasounds on the formation of non-interfacial IMCs and growth of interfacial IMCs are systematically analyzed by comparing with the traditional soldering process.
{"title":"Influence of ultrasounds on interfacial microstructures of Cu-Sn solder joints","authors":"Xu Han, Xiaoyan Li, P. Yao, Dalong Chen","doi":"10.1108/SSMT-06-2020-0026","DOIUrl":"https://doi.org/10.1108/SSMT-06-2020-0026","url":null,"abstract":"\u0000Purpose\u0000This study aims to investigate the interfacial microstructures of ultrasonic-assisted solder joints at different soldering times.\u0000\u0000\u0000Design/methodology/approach\u0000Solder joints with different microstructures are obtained by ultrasonic-assisted soldering. To analyze the effect of ultrasounds on Cu6Sn5 growth during the solid–liquid reaction stage, the interconnection heights of solder joints are increased from 30 to 50 μm.\u0000\u0000\u0000Findings\u0000Scallop-like Cu6Sn5 nucleate and grow along the Cu6Sn5/Cu3Sn interface under the traditional soldering process. By comparison, some Cu6Sn5 are formed at Cu6Sn5/Cu3Sn interface and some Cu6Sn5 are randomly distributed in Sn when ultrasonic-assisted soldering process is used. The reason for the formation of non-interfacial Cu6Sn5 has to do with the shock waves and micro-jets produced by ultrasonic treatment, which leads to separation of some Cu6Sn5 from the interfacial Cu6Sn5 to form non-interfacial Cu6Sn5. The local high pressure generated by the ultrasounds promotes the heterogeneous nucleation and growth of Cu6Sn5. Also, some branch-like Cu3Sn formed at Cu6Sn5/Cu3Sn interface render the interfacial Cu3Sn in ultrasonic-assisted solder joints present a different morphology from the wave-like or planar-like Cu3Sn in conventional soldering joints. Meanwhile, some non-interfacial Cu3Sn are present in non-interfacial Cu6Sn5 due to reaction of Cu atoms in liquid Sn with non-interfacial Cu6Sn5 to form non-interfacial Cu3Sn. Overall, full Cu3Sn solder joints are obtained at ultrasonic times of 60 s.\u0000\u0000\u0000Originality/value\u0000The obtained microstructure evolutions of ultrasonic-assisted solder joints in this paper are different from those reported in previous studies. Based on these differences, the effects of ultrasounds on the formation of non-interfacial IMCs and growth of interfacial IMCs are systematically analyzed by comparing with the traditional soldering process.\u0000","PeriodicalId":49499,"journal":{"name":"Soldering & Surface Mount Technology","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44662327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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