{"title":"锡膏合金、锡膏量和表面光洁度对焊点的影响","authors":"Abdallah Alakayleh , Sa'd Hamasha , Ali Alahmer","doi":"10.1016/j.microrel.2024.115457","DOIUrl":null,"url":null,"abstract":"<div><p>The reliability of solder joints is significantly influenced by the microstructure of SAC (Sn-Ag-Cu) solders, which is affected by various factors, including paste alloy, paste volume, and surface finish. This study explores the impact of these factors on the microstructure, thickness of the intermetallic compound (IMC) layer, hardness, and macro void presence in as-reflowed joints. Three lead-free solder alloys, namely SAC305 (Sn - 3.0Ag - 0.5Cu), SAC-Bi (Sn - 3.0Ag - 3.0Bi - 0.8Cu), and SAC-Bi-Sb (Sn - 3.4Ag - 3.2Bi - 3.0Sb - 0.7Cu), were tested with varying solder paste-to-sphere ratios with electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes. ENIG involves applying a thin layer of gold over a layer of nickel on the copper surfaces. Whereas OSP is a thin organic coating designed to protect copper surfaces from oxidation. The evaluation incorporated the analysis of Ag<sub>3</sub>Sn particles, IMC thickness, and voids through scanning electron and optical microscopy and X-ray images. Additionally, microhardness was assessed by indenting seven solder joints using the Phase II Model 900–391,391 micro-Vickers hardness tester. The study revealed that the SAC305 exhibited a higher presence of Ag<sub>3</sub>Sn particles than SAC-Bi and SAC-Bi-Sb. A direct proportionality was observed between paste volume and the quantity of Ag<sub>3</sub>Sn particles. Conversely, an inverse relationship was identified between paste volume and IMC layer thickness, resulting in a thinner IMC layer with higher paste volume, regardless of the paste alloy used. Furthermore, the use of ENIG led to a reduction in IMC thickness, attributed to the inhibitory effect of the Ni barrier. Doped alloys, specifically SAC-Bi and SAC-Bi-Sb, displayed superior microhardness compared to SAC305, owing to the strengthening and hardening effects of Bi and Sb. Regarding solder voiding, a noteworthy observation indicated that an increase in the quantity of solder paste resulted in the formation of larger voids.</p></div>","PeriodicalId":51131,"journal":{"name":"Microelectronics Reliability","volume":"160 ","pages":"Article 115457"},"PeriodicalIF":1.6000,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The impact of paste alloy, paste volume, and surface finish on solder joint\",\"authors\":\"Abdallah Alakayleh , Sa'd Hamasha , Ali Alahmer\",\"doi\":\"10.1016/j.microrel.2024.115457\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The reliability of solder joints is significantly influenced by the microstructure of SAC (Sn-Ag-Cu) solders, which is affected by various factors, including paste alloy, paste volume, and surface finish. This study explores the impact of these factors on the microstructure, thickness of the intermetallic compound (IMC) layer, hardness, and macro void presence in as-reflowed joints. Three lead-free solder alloys, namely SAC305 (Sn - 3.0Ag - 0.5Cu), SAC-Bi (Sn - 3.0Ag - 3.0Bi - 0.8Cu), and SAC-Bi-Sb (Sn - 3.4Ag - 3.2Bi - 3.0Sb - 0.7Cu), were tested with varying solder paste-to-sphere ratios with electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes. ENIG involves applying a thin layer of gold over a layer of nickel on the copper surfaces. Whereas OSP is a thin organic coating designed to protect copper surfaces from oxidation. The evaluation incorporated the analysis of Ag<sub>3</sub>Sn particles, IMC thickness, and voids through scanning electron and optical microscopy and X-ray images. Additionally, microhardness was assessed by indenting seven solder joints using the Phase II Model 900–391,391 micro-Vickers hardness tester. The study revealed that the SAC305 exhibited a higher presence of Ag<sub>3</sub>Sn particles than SAC-Bi and SAC-Bi-Sb. A direct proportionality was observed between paste volume and the quantity of Ag<sub>3</sub>Sn particles. Conversely, an inverse relationship was identified between paste volume and IMC layer thickness, resulting in a thinner IMC layer with higher paste volume, regardless of the paste alloy used. Furthermore, the use of ENIG led to a reduction in IMC thickness, attributed to the inhibitory effect of the Ni barrier. Doped alloys, specifically SAC-Bi and SAC-Bi-Sb, displayed superior microhardness compared to SAC305, owing to the strengthening and hardening effects of Bi and Sb. Regarding solder voiding, a noteworthy observation indicated that an increase in the quantity of solder paste resulted in the formation of larger voids.</p></div>\",\"PeriodicalId\":51131,\"journal\":{\"name\":\"Microelectronics Reliability\",\"volume\":\"160 \",\"pages\":\"Article 115457\"},\"PeriodicalIF\":1.6000,\"publicationDate\":\"2024-07-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Microelectronics Reliability\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0026271424001379\",\"RegionNum\":4,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENGINEERING, ELECTRICAL & ELECTRONIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microelectronics Reliability","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0026271424001379","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
The impact of paste alloy, paste volume, and surface finish on solder joint
The reliability of solder joints is significantly influenced by the microstructure of SAC (Sn-Ag-Cu) solders, which is affected by various factors, including paste alloy, paste volume, and surface finish. This study explores the impact of these factors on the microstructure, thickness of the intermetallic compound (IMC) layer, hardness, and macro void presence in as-reflowed joints. Three lead-free solder alloys, namely SAC305 (Sn - 3.0Ag - 0.5Cu), SAC-Bi (Sn - 3.0Ag - 3.0Bi - 0.8Cu), and SAC-Bi-Sb (Sn - 3.4Ag - 3.2Bi - 3.0Sb - 0.7Cu), were tested with varying solder paste-to-sphere ratios with electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes. ENIG involves applying a thin layer of gold over a layer of nickel on the copper surfaces. Whereas OSP is a thin organic coating designed to protect copper surfaces from oxidation. The evaluation incorporated the analysis of Ag3Sn particles, IMC thickness, and voids through scanning electron and optical microscopy and X-ray images. Additionally, microhardness was assessed by indenting seven solder joints using the Phase II Model 900–391,391 micro-Vickers hardness tester. The study revealed that the SAC305 exhibited a higher presence of Ag3Sn particles than SAC-Bi and SAC-Bi-Sb. A direct proportionality was observed between paste volume and the quantity of Ag3Sn particles. Conversely, an inverse relationship was identified between paste volume and IMC layer thickness, resulting in a thinner IMC layer with higher paste volume, regardless of the paste alloy used. Furthermore, the use of ENIG led to a reduction in IMC thickness, attributed to the inhibitory effect of the Ni barrier. Doped alloys, specifically SAC-Bi and SAC-Bi-Sb, displayed superior microhardness compared to SAC305, owing to the strengthening and hardening effects of Bi and Sb. Regarding solder voiding, a noteworthy observation indicated that an increase in the quantity of solder paste resulted in the formation of larger voids.
期刊介绍：
Microelectronics Reliability, is dedicated to disseminating the latest research results and related information on the reliability of microelectronic devices, circuits and systems, from materials, process and manufacturing, to design, testing and operation. The coverage of the journal includes the following topics: measurement, understanding and analysis; evaluation and prediction; modelling and simulation; methodologies and mitigation. Papers which combine reliability with other important areas of microelectronics engineering, such as design, fabrication, integration, testing, and field operation will also be welcome, and practical papers reporting case studies in the field and specific application domains are particularly encouraged.
Most accepted papers will be published as Research Papers, describing significant advances and completed work. Papers reviewing important developing topics of general interest may be accepted for publication as Review Papers. Urgent communications of a more preliminary nature and short reports on completed practical work of current interest may be considered for publication as Research Notes. All contributions are subject to peer review by leading experts in the field.
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