scholarly journals Die Attach of Power Devices Using Silver Sintering – Bonding Process Optimisation and Characterization

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000084-000090 ◽  
Author(s):  
Cyril Buttay ◽  
Amandine Masson ◽  
Jianfeng Li ◽  
Mark Johnson ◽  
Mihai Lazar ◽  
...  
Keyword(s):  
Operating Temperature ◽  
Bonding Process ◽  
Attractive Alternative ◽  
Special Focus ◽  
Process Optimisation ◽  
Melting Points ◽  
Power Devices ◽  
Die Attach ◽  
Silver Sintering ◽  
Soldering Alloys

Silver sintering is becoming an attractive alternative to soldering, especially for high temperature applications. Indeed, the increase in operating temperature requires new soldering alloys with even higher melting points. Silver sintering, on the contrary, is a solution which only require moderate (<300°C) process temperature. In this paper, we present the implementation of a die attach technique based on sintering of some silver paste, with a special focus on the practical considerations. A good quality bond can be achieved by paying attention to the assembly process.

scholarly journals Pressureless Silver Sintering Die-Attach for SiC Power Devices

2013 ◽  
Vol 740-742 ◽  
pp. 851-854 ◽  
Author(s):  
Stanislas Hascoët ◽  
Cyril Buttay ◽  
Dominique Planson ◽  
Rodica Chiriac ◽  
Amandine Masson
Keyword(s):  
Sintering Temperature ◽  
Electronic Devices ◽  
Power Electronic ◽  
Power Devices ◽  
Ramp Rate ◽  
Drying Time ◽  
Die Attach ◽  
Silver Sintering ◽  
The Cost ◽  
Manufacturing Parameters

Pressureless silver sintering is an interesting die-attach technique that could overcome the reliability limitations of the power electronic devices caused by their packaging. In this paper, we study the manufacturing parameters that affect the die attach: atmosphere, drying time, heating ramp rate, sintering temperature and duration. It is found that sintering under air gives better results, but causes the substrates to oxidize. Sintering under nitrogen keeps the surfaces oxide-free, at the cost of a weaker attach.

An Innovative High Thermal Conductive Solderable Adhesive

2011 ◽  
Vol 2011 (1) ◽  
pp. 000852-000856
Author(s):  
Mary Liu ◽  
Wusheng Yin
Keyword(s):  
High Power ◽  
Low Cost ◽  
Bonding Process ◽  
Advanced Materials ◽  
Reflow Process ◽  
Power Devices ◽  
Process Yield ◽  
Thermal Compression ◽  
Soldering Temperature ◽  
Die Attach

With increasing LED development and production, thermal issues are becoming more and more important for LED devices, particularly true for high power LED and also for other high power devices. In order to dissipate the heat from the device efficiently, Au80Sn20 alloy is being used in the industry now. However there are a few drawbacks for Au80Sn20 process: (1) higher soldering temperature, usually higher than 320 °C; (2) low process yield; (3) too expensive. In order to overcome the shortcomings of Au80Sn20 process, YINCAE Advanced Materials, LLC has invented a new solderable adhesive – TM 230. Solderable adhesives are epoxy based silver adhesives. During the die attach reflow process, the solder material on silver can solder silver together, and die with pad together. After soldering, epoxy can encapsulate the soldered interface, so that the thermal conductivity can be as high as 58 W/mk. In comparison to Au80Sn20 reflow process, the solderable adhesive has the following advantages: (1) low process temperature – reflow peak temperature of 230 °C; (2) high process yield – mass reflow process instead of thermal compression bonding process; (3) low cost ownership. In this paper we are going to present the die attach process of solderable adhesive and the reliability test. After 1000 h lighting of LED, it has been found that there is almost no decay in the light intensity by using solderable adhesive – TM 230.

Analysis of Two Electrical Failures Caused by Die Attach of Exposed Pad Package

2014 ◽  
Author(s):  
Jinglong Li ◽  
Motohiko Masuda ◽  
Yi Che ◽  
Miao Wu
Keyword(s):  
Bonding Process ◽  
Die Attach ◽  
Die Bonding ◽  
Generic Analysis

Abstract Die attach is well known in die bonding process. Its electrical character is simple. But some failures caused by die attach are not so simple. And it is not proper to analyze by a generic analysis flow. The analysis of two failures caused by die attach are presented in this paper.

Organic chemical devulcanization of rubber vulcanizates in supercritical carbon dioxide and associated less eco-unfriendly approaches: A review

2021 ◽  
pp. 0734242X2110085
Author(s):  
Jabulani I Gumede ◽  
Buyiswa G Hlangothi ◽  
Chris D Woolard ◽  
Shanganyane P Hlangothi
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Negative Impact ◽  
Raw Materials ◽  
Chemical Components ◽  
Organic Chemical ◽  
Attractive Alternative ◽  
Special Focus ◽  
Waste Tyres ◽  
Supercritical Carbon

There is a growing need to recover raw materials from waste due to increasing environmental concerns and the widely adopted transition to circular economy. For waste tyres, it is necessary to continuously develop methods and processes that can devulcanize rubber vulcanizates into rubber products with qualities and properties that can closely match those of the virgin rubber. Currently, the most common, due to its efficiency and perceived eco-friendliness in recovering raw rubber from waste rubbers, such as tyres, is devulcanization in supercritical carbon dioxide (scCO2) using commercial and typical devulcanizing agents. The scCO2 has been generally accepted as an attractive alternative to the traditional liquid-based devulcanization media because of the resultant devulcanized rubber has relatively better quality than other processes. For instance, when scCO2 is employed to recover rubber from waste tyres (e.g. truck tyres) and the recovered rubber is blended with virgin natural rubber (NR) in various compositions, the curing and mechanical properties of the blends closely match those of virgin NR. The atmospheric toxicity and cost of the commonly used devulcanization materials like chemical agents, oils and solvents have enabled a shift towards utilization of greener (mainly organic) and readily available devulcanization chemical components. This literature review paper discusses the approaches, which have less negative impact on the environment, in chemical devulcanization of rubber vulcanizates. A special focus has been on thermo-chemical devulcanization of waste tyres in scCO2 using common organic devulcanizing agents.

Energy and Eco-Sustainability using Pressure-less Silver Sintering for RF Power Electronics

2019 ◽  
Vol 2019 (1) ◽  
pp. 000344-000359
Author(s):  
Evan A. Hueners ◽  
Richard D. Hueners ◽  
Anthony D. F. O' Sullivan ◽  
M. Redzuan Zin
Keyword(s):  
Power Electronics ◽  
High Speed ◽  
Bond Line ◽  
Acoustic Microscopy ◽  
Rf Power ◽  
Technical Requirements ◽  
Die Attach ◽  
Effective Manner ◽  
Confocal Scanning ◽  
Silver Sintering

Abstract Energy & Eco-Sustainability using Pressureless Silver Sintering for RF Power Electronics A virtually void free die attach was successfully achieved using a fixed but critical volume of Ag sinter paste by a process of pressureless sintering on a multi-axis cartesian style bonder, retro-fitted with with a high-speed jetting dispenser. While this process potentially offered an ideal combination of cost-effectiveness, control and speed, it required the development of additional software protocols to secure the level of performance demanded of the dispenser to meet exacting technical requirements. This proprietary adaptation we term “Fixed BLT” software, and over five test pieces we were consistently able to deliver a fixed height bond-line of circa 70% of bond height, translating as 50 um before sinter and 30 um after. In each case the result was a virtually bond free void secured in a timely, repeatable, commercially effective manner. The absence of voids was verified through industry standard non-destructive analysis utilizing confocal scanning acoustic microscopy (CSAM).

Evaluation of Low Cost, High Temperature Die and Substrate Attach Materials for Silicon Carbide (SiC) Power Modules

2018 ◽  
Vol 2018 (1) ◽  
pp. 000317-000325
Author(s):  
Sayan Seal ◽  
Brandon Passmore ◽  
Brice McPherson
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Operating Conditions ◽  
Acoustic Microscopy ◽  
Switching Frequency ◽  
Power Devices ◽  
Formidable Challenge ◽  
Die Attach ◽  
Power Modules ◽  
High Switching Frequency

Abstract The performance of SiC power devices has demonstrated superior characteristics as compared to conventional Silicon (Si) devices. Some of the advantages of SiC power devices over Si include higher voltage blocking capability, low specific on-resistance, high switching frequency, high temperature operation, and high power density. Thus, SiC modules are capable of processing significant levels of power within much smaller volumes compared with its Si counterparts. These high thermal loads present a formidable challenge in integrating SiC devices in power modules. For example, known-good materials and processes for silicon power modules are not rated at the aggressive operating conditions associated with SiC devices. Two of the most critical interfaces in a power electronics module are the die-attach and substrate- attach. A degradation in these interfaces often results in potentially catastrophic electrical and thermal failure. Therefore, it is very important to thoroughly evaluate die-attach materials before implementing them in SiC power modules. This paper presents the methodology for the evaluation of die attach materials for SiC power modules. Preforms of a lead-free high-temperature attach material were used to perform a die and substrate attach process on a conventional power module platform. The initial attach quality was inspected using non- destructive methods consisting of acoustic microscopy and x-ray scanning. Die attach and substrate attach voiding of < 5% was obtained indicating a very good attach quality. Cross-sectioning techniques were used to validate the inspection methods. The initial attach strength was measured using pull tests and shear tests. The measurements were repeated at the rated temperature of the module to ensure that the properties did not degrade excessively at the service temperature. At the rated module temperature of 175 °C, the die bonding strength was found to be ~ 75 kg. This was only 25% lower than the strength at room temperature. In addition, the contact pull strength was measured to be > 90 kg at 175 °C, which was 25% lower than the value measured at room temperature. The effect of power cycling and thermal cycling on the quality and strength of the die and substrate attach layers was also investigated.

Ink-jetting for Electronic Assembly

2010 ◽  
Vol 2010 (1) ◽  
pp. 000929-000934
Author(s):  
Georg Meyer-Berg ◽  
Gottfried Beer ◽  
Klaus Pressel
Keyword(s):  
Void Formation ◽  
Experimental Results ◽  
Special Focus ◽  
Electronic Assembly ◽  
Filler Size ◽  
Die Attach ◽  
Ink Jet ◽  
The Future

We report experimental results on applying ink-jetting to dedicated system-in-package technologies. Special focus is on die-attach, vertical and horizontal interconnects. Our experiments on die attach experiments demonstrate that today we have still too high expenses to adapt materials, filler size and viscosity. The filling experiments of 150μm diameter vertical through encapsulant vias for package-on-package applications with ink-jetting showed void formation, which requires still smaller ink jet drops in the future. For formation of horizontal interconnects, e.g. for rerouting, by ink-jetting we observe that a functionalization of the surfaces e.g. with plasma or sulfur acid is required. Based on these project results and experience we suggest a roadmap for ink-jetting using parallel nozzles and single nozzles.

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