Thermocompression bonding of Ag-MWCNTs nanocomposite films as an alternative die-attach solution for high temperature packaging of SiC devices

2012 ◽  
Author(s):  
Vanessa Smet ◽  
Mamun Jamal ◽  
Alan Mathewson ◽  
Kafil M. Razeeb
Keyword(s):  
High Temperature ◽  
Nanocomposite Films ◽  
Die Attach ◽  
Thermocompression Bonding

High-Temperature Die-Attach Technology for Power Devices Based on Thermocompression Bonding of Thin Ag Films

2013 ◽  
Vol 3 (4) ◽  
pp. 533-542 ◽  
Author(s):  
Vanessa Smet ◽  
Mamun Jamal ◽  
Finbarr Waldron ◽  
Frank Stam ◽  
Alan Mathewson ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Devices ◽  
Die Attach ◽  
Thermocompression Bonding

Thermally stable high temperature die attach solution

2016 ◽  
Vol 89 ◽  
pp. 1310-1314 ◽  
Author(s):  
Seyed Amir Paknejad ◽  
Ali Mansourian ◽  
Yohan Noh ◽  
Khalid Khtatba ◽  
Samjid H. Mannan
Keyword(s):  
High Temperature ◽  
Thermally Stable ◽  
Die Attach

Silicon Carbide Die Attach Scheme for 500°C Operation

2000 ◽  
Vol 622 ◽  
Author(s):  
Liang-Yu Chen ◽  
Gary W. Hunter ◽  
Philip G. Neudeck
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Semiconductor Devices ◽  
Single Crystal Silicon ◽  
Film Material ◽  
Crystal Silicon ◽  
Pure Alumina ◽  
Die Attach

ABSTRACTSingle crystal silicon carbide (SiC) has such excellent physical, chemical, and electronic properties that SiC based semiconductor electronics can operate at temperatures in excess of 600°C well beyond the high temperature limit for Si based semiconductor devices. SiC semiconductor devices have been demonstrated to be operable at temperatures as high as 600°C, but only in a probe-station environment partially because suitable packaging technology for high temperature (500°C and beyond) devices is still in development. One of the core technologies necessary for high temperature electronic packaging is semiconductor die-attach with low and stable electrical resistance. This paper discusses a low resistance die-attach method and the results of testing carried out at both room temperature and 500°C in air. A 1 mm2 SiC Schottky diode die was attached to aluminum nitride (AlN) and 96% pure alumina ceramic substrates using precious metal based thick-film material. The attached test die using this scheme survived both electronically and mechanically performance and stability tests at 500°C in oxidizing environment of air for 550 hours. The upper limit of electrical resistance of the die-attach interface estimated by forward I-V curves of an attached diode before and during heat treatment indicated stable and low attach-resistance at both room-temperature and 500°C over the entire 550 hours test period. The future durability tests are also discussed.

A multi-pronged approach to low-pressure Cu sintering using surface-modified particles, substrate and chip metallization

2019 ◽  
Vol 2019 (1) ◽  
pp. 000387-000392 ◽  
Author(s):  
Sri Krishna Bhogaraju ◽  
Omid Mokhtari ◽  
Jacopo Pascucci ◽  
Fosca Conti ◽  
Hiren R Kotadia ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Cost ◽  
Surface Modifications ◽  
Low Pressure ◽  
Bonding Pressure ◽  
High Tendency ◽  
Promising Alternative ◽  
Die Attach ◽  
Bandgap Semiconductors ◽  
Surface Modified

Abstract High temperature power electronics based on wide-bandgap semiconductors have prominent applications, such as automotive, aircrafts, space exploration, oil/gas extraction, electricity distribution. Die-attach bonding process is an essential process in the realization of high temperature power devices. Here Cu offers to be a promising alternative to Ag, especially because of thermal and mechanical properties on par with Ag and a cost advantage by being a factor 100 cheaper than Ag. With the aim to achieve a low-pressure Cu sintering process, a low cost wet chemical etching process is developed to selectively etch Zn from brass to create nano-porous surface modifications to enhance sinterability, enabling sintering with low bonding pressure of 1MPa and at temperatures below 300°C. However, high tendency of Cu to oxidize poses a major challenge in realizing stable interconnects. For this purpose, in this contribution, we present the use of polyethylene-glycol 600 as reducing binder in the formulation of the Cu sintering paste. Finally, we propose a multi-pronged approach based on three crucial factors: surface-modified substrates, nanostructured surface modifications on micro-scale Cu-alloy particles and use of a reducing binder in the Cu particle paste.

Microstructural Evolution and Thermal Stability Characterization of a High Temperature Die Attach Lead-Free System

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 1-11 ◽  
Author(s):  
Rogie I. Rodriguez ◽  
Dimeji Ibitayo ◽  
Pedro Quintero
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Microstructural Evolution ◽  
Diffusion Mechanism ◽  
Processing Temperature ◽  
Mechanical And Thermal Properties ◽  
Promising Alternative ◽  
Free System ◽  
Die Attach

There is a need for electromechanical devices capable of operating in high temperature environments (>200°C) for a wide variety of applications. Today's wide-bandgap (WBG) semiconductor based power electronics have demonstrated a potential of operating above 400°C, however they are still limited by packaging. Among the most promising alternative is the Au-Sn eutectic solder, which have been widely used due to its excellent mechanical and thermal properties. However, the operating temperature of this metallurgical system is still limited to ∼250°C owing to its melting temperature of 280°C. Therefore, a higher temperature resistant system is much needed, but without affecting the current processing temperature of ∼325°C typically exhibited in most high temperature Pb-Free solders. This paper presents the development and characterization of a fluxless die attach soldering process based on gold enriched solid liquid inter-diffusion (SLID). A low melting point material (eutectic Au-Sn) was deposited in the face of a substrate, whereas a high melting point material, gold in this instance, was deposited in its mating substrate. Deposition of all materials was performed using a jet vapor deposition (JVD) equipment where thicknesses were controlled to achieve specific compositions in the mixture. Sandwiched coupons where isothermally processed in a vacuum reflow furnace. SEM and EDS were employed to reveal the microstructural evolution of the samples in order to study the interfacial reactions of this fluxless bonding process. Mechanical characterization of the each individual intermetallic phase was achieved by nanoindentation. Differential scanning calorimetry demonstrated the progression of the SLID process by quantifying the remaining low melting point constituent as a function of time and temperature. Post-processed samples confirmed the inter-diffusion mechanism as evidenced by the formation of sound joints that proved to be thermally stable up to ∼490°C after the completion of the SLID process.

Die-Attach Voiding Reduction in Gold Alloy Solder Preforms

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000099-000102
Author(s):  
Bernard Leavitt ◽  
Andy C. Mackie
Keyword(s):  
High Temperature ◽  
Eutectic Alloy ◽  
Hot Spots ◽  
Gold Alloy ◽  
High Reliability ◽  
Eutectic Alloys ◽  
Power Semiconductor ◽  
Power Semiconductor Devices ◽  
Die Attach ◽  
Alloy Solder

Abstract The need for high-temperature solders is growing as RF and power semiconductor devices continue to get smaller, with power density increasing both as a consequence of the shrink and as a result of increased power ratings. AuSn20 eutectic solder (Indalloy®182) has been the workhorse for high-temperature, high-reliability, small die-attach applications for many years; however, as junction temperatures (Tj) increase, the gold-tin eutectic is beginning to reach its limit of utility. Higher temperatures cause increased thermal fatigue, and even delamination is seen at the solder joints. The next option for RF and power semiconductor manufacturers needing these higher temperatures is either AuGe12 (Indalloy®183) or AuSi3.2 (Indalloy®184) eutectic alloy (see Table I).Table 1.Key properties of Au-based eutectic alloys. Over the years, many customers have tried AuGe12 and the feedback has been that the alloy has poor solderability, which manifests as large voids in the bond. Voids are poor conductors of heat, which create hot spots, and are the primary cause of premature failures.

Mobile Packaging and Interconnect Trends

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 1-21
Author(s):  
Brandon Prior
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Thick Film ◽  
Cross Sections ◽  
Shear Test ◽  
Short Review ◽  
Test Machine ◽  
Die Attach ◽  
Shear Failures ◽  
Film Substrate

This paper will focus on emerging and fast growth package solutions to meet mobile products' density and cost requirements. A short review of where package miniaturization and modularization has taken us so far, and where it will lead in the next 5 years. Teardowns of high density systems and packages will be used to illustrate key points. Low temperature Ag sintering technology provides a lead-free die attachment compatible with high temperature (300°C) applications. Previous work with Ag sintering has required some pressure during the sintering process or been limited to small area die. In this paper, a pressureless sintering of micro-scale silver paste procedure is presented for large (8mm x 8mm) area die. Experimental combinations included: Ag metallized Si die, Au metallized Si die, Ag thick film substrate metallization, Au thick film substrate metallization, PdAg thick film metallization and sintering temperature. For Au metallization (die and/or substrate), the initial shear strength results were good with 8mm x 8mm die sintered at lower temperatures (200°C). The shear strength was out range of our shear test machine (100 kg), corresponding to >15.3 MPa. However, after aging for 24 hours at 300°C, the shear strength dropped significantly to 40.38 Kg (6.183 MPa). An SEM was used to characterize cross sections of as-built and aged sample. The decrease in die shear strength with high temperature sintering (250°C and 300°C) or high temperature aging is attributed to surface diffusion of Ag along the Au surface resulting in a dense Ag layer adjacent to the Au surface and a depletion layer within the die attach on the opposite side of the the dense Ag layer. Shear failures occurred through the depleted region. For Ag metallization, no decrease in shear strength was observed with 300°C aging. Shear strength of 8x8cm2 dies was out range of our shear test machine (>100 kg, >15.3 MPa) as-built. The shear strength remained out of range (>15.3MPa) after more than 2000 hours of 300C aging.

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.

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