Metallurgy for SiC Die Attach for Operation at 500°C

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000008-000017 ◽  
Author(s):  
Ping Zheng ◽  
Phillip Henson ◽  
R. Wayne Johnson ◽  
Liangyu Chen
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Failure Surface ◽  
Nano Particle ◽  
Test Results ◽  
Shear Tests ◽  
Die Attach ◽  
Film Layer ◽  
Potential Failure ◽  
Dc Bias

Metallurgy for high temperature SiC die attach involves the substrate metallization, die metallization, and die attach material. This paper examines off-eutectic Au-Sn as the die attach alloy with a PtAu thick film metallization on AlN substrates. A pure Au thick film layer was printed over the PtAu thick film layer. The SiC backside metallizations evaluated were Ti/TaSi/Pt/Au and Cr/NiCr/Au. Die shear tests were performed after aging at 500°C and after thermal cycling. The shear test results and failure surface analysis are discussed. Nanoparticle Ag and liquid transient phase bonding with Ag based metallurgies have been proposed for high temperature die attach. Data on the migration of sintered nano-particle Ag and thin film Ag dc bias during storage in air at 300°C and 375°C are presented. Migration of Ag is a potential failure mechanism for Ag based high temperature metallurgies.

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.

Test Results of Sintered Nanosilver Paste Die Attach for High-Temperature Applications

2016 ◽  
Vol 13 (1) ◽  
pp. 6-16 ◽  
Author(s):  
Paul Croteau ◽  
Sayan Seal ◽  
Ryan Witherell ◽  
Michael Glover ◽  
Shashank Krishnamurthy ◽  
...  
Keyword(s):  
High Temperature ◽  
Cooling System ◽  
Wide Band ◽  
Power Converter ◽  
Test Results ◽  
Wide Band Gap ◽  
Strain Behavior ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Sintered Silver

The emergence of wide band gap devices has pushed the boundaries of power converter operations and high power density applications. It is desirable to operate a power inverter at high switching frequencies to reduce passive filter weight and at high temperature to reduce the cooling system requirement. Therefore, materials and components that are reliable at temperatures ranging from −55°C to 200°C, or higher, are needed. Sintered silver is receiving significant attention in the power electronic industry. The porous nature of sintered nanosilver paste with a reduced elastic modulus has the potential to provide strain relief between the die component and substrate while maintaining its relatively high melting point after sintering. The test results presented herein include tensile testing to rupture of sintered silver film to characterize stress-strain behavior, as well as die shear and thermal cyclic tests of sintered silver-bonded silicon die specimens to copper substrates to determine shear strength and reliability.

scholarly journals Shear strength behaviour of sand-bentonite mixtures with pumice additivite under high temperature

2020 ◽  
Vol 205 ◽  
pp. 04004
Author(s):  
Esra Güneri ◽  
Yeliz Yükselen Aksoy
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Room Temperature ◽  
Engineering Properties ◽  
Direct Shear ◽  
Test Results ◽  
Soil Behavior ◽  
Shear Tests ◽  
Volume Deformation ◽  
Direct Shear Tests

Depending on increase in the number and type of energy geostructures, studies on the change in soil behavior against heat increase becomes more important. The engineering properties such as permeability, volume deformation of surrounding soils around energy structures mustn’t alter in the presence of heat and thermal cycles. Pumice is a material used in many fields especially for thermal insulation. For that reason, pumice can be used for increasing the resistance of soils in the presence of heat. In this study, the shear strength behavior of sand-bentonite mixtures was investigated with pumice additive under high temperature. In the experiments, 10% and 20% pumice were added to 10% and 20% sand-bentonite mixtures and compaction, direct shear tests were conducted. The direct shear tests were performed both room temperature and under 80°C. The results have shown that the pumice additive increased the shear strength of sand-bentonite mixtures under high temperature when compared the test results under room temperature.

Component Attachment with Pressureless Sintering for 300°C Applications

2016 ◽  
Vol 2016 (HiTEC) ◽  
pp. 000226-000233
Author(s):  
Fang Yu ◽  
Jinzi Cui ◽  
Zhangming Zhou ◽  
R. Wayne Johnson ◽  
Michael C. Hamilton
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Cross Sections ◽  
High Power ◽  
Shear Force ◽  
Passive Component ◽  
Pressureless Sintering ◽  
High Temperature Electronics ◽  
Die Attach ◽  
The Mean

Abstract With an increased demand for high power and high temperature electronics, Ag sintering paste has been considered a promising Pb-free die attach material candidate for these applications. A large amount of research has been performed investigating pressure and pressureless Ag sintering for die attach. In this work, passive component (chip resistor) attachment with Ag sintering was explored. Due to termination geometry differences between resistors and die, different processing procedures and parameters were developed. For PtAu terminated resistors, the mean shear force of as-built samples on thick film Ag metallized substrates was 90 N, but dropped to 18.6 N after 1500 hours at 300°C. Formation of a dense Ag layer near the PtAu resistor termination and a void region near the thick film metallization was observed in cross-sections after 1000 hours at 300°C. For PdAg terminated resistors with a plated Ni/Au finish, the initial shear force results were low due to Ag diffusion along Au metallization surface. For PdAg terminated resistors with Ag thick film substrates, the initial shear force was approximately 60 N and remained in the range of 50–70 N during aging at 300°C for 1500 hours. A new thick film metallization (Au+Ag) was developed to enable the use of thick film Au interconnect metallization.

Component Attachment with Pressureless Ag Sintering for 300°C Applications

2016 ◽  
Vol 13 (4) ◽  
pp. 155-162
Author(s):  
Fang Yu ◽  
Jinzi Cui ◽  
Zhangming Zhou ◽  
R. Wayne Johnson ◽  
Michael C. Hamilton
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Cross Sections ◽  
High Power ◽  
Shear Force ◽  
Passive Component ◽  
High Temperature Electronics ◽  
Die Attach ◽  
The Mean

With an increased demand for high-power and high-temperature electronics, Ag sintering paste has been considered a promising Pb-free die-attach material candidate for these applications. Extensive research has been carried out investigating pressure and pressureless Ag sintering for die attach. In this work, passive component (chip resistor) attachment with Ag sintering was explored. Due to termination geometry differences between resistors and dies, different processing procedures and parameters were developed. For PtAu terminated resistors, the mean shear force of as-built samples on thick-film Ag metallized substrates was 90 N, but dropped to 18.6 N after 1,500 h at 300°C. Formation of a dense Ag layer near the PtAu resistor termination and a void region near the thick-film metallization was observed in cross sections after 1,000 h at 300°C. For PdAg terminated resistors with a plated Ni/Au finish, the initial shear force results were low due to Ag diffusion along Au metallization surface. For PdAg terminated resistors with Ag thick-film substrates, the initial shear force was ~60 N and remained in the range of 50–70 N during aging at 300°C for 1,500 h. A new thick-film metallization (Au + Ag) was developed to enable the use of thick-film Au interconnect metallization.

Joining Low Temperature Co-Fired Ceramics, Al2O3 and SiC Substrates for Higher Operating Temperature Applications

2016 ◽  
Vol 258 ◽  
pp. 631-634
Author(s):  
Jakub Somer ◽  
Martin Klíma ◽  
Petr Machac ◽  
Ivan Szendiuch
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
Low Temperature ◽  
Thick Film ◽  
Operating Temperature ◽  
Temperature Cycling ◽  
Shear Tests ◽  
Film Layer ◽  
Specific Temperature ◽  
Scanning Electron

The article deals with forming solid joints of Low Temperature Co-fired Ceramic with Alumina or Silicon Carbide chips. The aim of this study is to find material of standard thick film layer process, which would be useful for electronic chip packages designed for higher operating temperatures (from 150 up to 800 °C). Heraeus Hera Lock 2000 Low Temperature Co-fired Ceramics (LTCC) was chosen, because of its nearly zero shrinkage during firing. Also other LTCC types were used to comparison of results. Conductive and isolating thick film pastes are used for joining. Temperature cycling of samples was applied. Strength of cycled samples was investigated by mechanical shear tests. The structure of microsection of joints was analyzed using optical and scanning electron microscope. The results show that thick film pastes are usable for joining above mentioned materials in specific temperature range.

Investigation of Thick Film Technology for High Temperature Applications

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000184-000191 ◽  
Author(s):  
Zhangming Zhou ◽  
Jinzi Cui ◽  
Fang Yu ◽  
Kun Fang ◽  
Zhenzhen Shen ◽  
...  
Keyword(s):  
High Temperature ◽  
Fracture Surface ◽  
Thick Film ◽  
Leakage Current ◽  
Surface Analysis ◽  
Constant Bias ◽  
Fracture Surface Analysis ◽  
Dc Bias ◽  
Thick Film Technology ◽  
Temperature Applications

For electronics operating at 300°C, thick film technology has been proposed as a suitable interconnection technology to create modules. This work examines the leakage current with constant bias (100V) at 300°C. The leakage current increased significantly within the first few hours of aging. The effect of 300°C aging with dc bias on the adhesion of multilayer thick film test structures was also studied. The aged adhesion was a function of bias polarity. Fracture surface analysis results are presented. Bi in the PtPdAu conductor appears to play a role in both the leakage current and adhesion phenomena observed.

Characterization of AgBiX™ Solder Paste on Thick Film for 200°C Applications

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000340-000346 ◽  
Author(s):  
Zhenzhen Shen ◽  
Wayne Johnson ◽  
Michael C. Hamilton
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Solidus Temperature ◽  
Passive Component ◽  
Solder Paste ◽  
Die Attach ◽  
High Temperature Storage ◽  
Temperature Storage

AgBiX™ (Indium Corporation) solder paste has a solidus temperature of ∼262°C after reflow, which is suitable for passive component, semiconductor and power die attach for 200°C applications. In this work, the paste has been used to assemble SiC die with Ti/Ni/Ag thin film metallization to Ag and PdAg thick film substrates. High temperature storage testing (200°C) was preformed to characterize the reliability of the assemblies. Surface mount chip resistors attached to thick film substrates were also subject to high temperature storage. Comparisons of the performance of die attach and resistor attach on Ag substrates and PdAg substrates are made. EDX and failure analysis was used to understand the role of Pd on the failure mode and lower aged shear strengths with the thick film PdAg conductors.

Test Results of Sintered Nano-Silver Paste Die Attach for High Temperature Applications

2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000037-000049
Author(s):  
Paul Croteau ◽  
Sayan Seal ◽  
Ryan Witherell ◽  
Michael Glover ◽  
Shashank Krishnamurthy ◽  
...  
Keyword(s):  
High Temperature ◽  
Cooling System ◽  
Wide Band ◽  
Power Converter ◽  
Test Results ◽  
Silver Paste ◽  
Nano Silver ◽  
Strain Behavior ◽  
Die Attach ◽  
Sintered Silver

The emergence of wide band gap devices has pushed the boundaries of power converter operations and high power density applications. It is desirable to operate a power inverter at high switching frequencies to reduce passive filter weight and at high temperature to reduce the cooling system requirement. Therefore, materials and components that are reliable at temperatures ranging from −55 to 200 °C, or higher, are needed. Sintered silver is receiving significant attention in the power electronic industry. The porous nature of sintered nano-silver paste with a reduced elastic modulus has the potential to provide strain relief between the die component and substrate while maintaining its relatively high melting point after sintering. The test results presented herein include tensile testing to rupture of sintered silver film to characterize stress strain behavior, as well as die shear and thermal cyclic tests of sintered silver bonded silicon die specimens to copper substrates to determine shear strength and reliability.

scholarly journals Test Vehicle for Studying Thermal Conductivity of Die Attach Adhesives for High Temperature Electronics

2012 ◽  
Vol 188 ◽  
pp. 238-243
Author(s):  
Conor Slater ◽  
Fabrizio Vecchio ◽  
Thomas Maeder ◽  
Peter Ryser
Keyword(s):  
Thermal Conductivity ◽  
Shear Strength ◽  
High Temperature ◽  
Thick Film ◽  
Test Vehicle ◽  
High Temperature Electronics ◽  
Temperature Decay ◽  
Die Attach ◽  
Viable Method ◽  
Degree Of Degradation

Polymer adhesives offer a viable method for mounting silicon dies for high temperature applications. Here a test vehicle for comparing the thermal conductivity of different die attach materials is presented. The setup can be used to determine the degree of degradation of polymers. It consists of a mock die that has an integrated thick film heater, which is mounted onto a substrate. In operation, the substrate is placed on a heatsink and the die is heated. When the temperature reaches equilibrium the heater is switched off and the temperature of the die is measured as it cools. The time constant of the temperature decay is calculated to give the thermal conductivity. In this paper the thermal conductivity of an epoxy die attach adhesive is compared to its shear strength.

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