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.

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.

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.

Improved sinterability of particles to substrates by surface modifications on substrate metallization

2019 ◽  
Vol 2019 (HiTen) ◽  
pp. 000066-000070 ◽  
Author(s):  
Sri Krishna Bhogaraju ◽  
Omid Mokhtari ◽  
Jacopo Pascucci ◽  
Fosca Conti ◽  
Gordon Elger
Keyword(s):  
High Temperature ◽  
High Power ◽  
Low Cost ◽  
Surface Modifications ◽  
Bonding Pressure ◽  
Light Emitting ◽  
High Temperature Electronics ◽  
Die Attach ◽  
N2 Atmosphere ◽  
Surface Modified

Abstract Sintering under pressure has been in the forefront of the research and development over the past decade as an alternative to high temperature soldering and die-attach bonding for high temperature electronics. However, high bonding pressure is a deterrent to mass industrialization due to the high costs involved in the design of special tooling and complex process control parameters. Further, it can cause device cracking, especially while working with sensitive high power optoelectronics devices (e.g. high power light emitting diodes). Therefore, alternatives to enhance sinterability are highly requested. Substrate metallization is observed to play an important role while sintering. An innovative low cost method to have nanostructured surface modifications on the substrates is realized and presented here. The method is applied to enhance sinterability of Cu particles to substrate. Shear tests on samples with surface modified substrates are promising with results of ca. 25 MPa, which is 24% better than sintering on unmodified bare Cu substrate. Sintering was enabled by in-house developed hybrid Cu paste under pressureless sintering conditions of 300°C, for 60 min, and under N2 atmosphere.

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.

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.

High Temperature Reliability of High-power LED Module Using Die Attach Material of Nano-silver Paste

2016 ◽  
Vol 37 (9) ◽  
pp. 1159-1165
Author(s):  
陈佳 CHEN Jia ◽  
李欣 LI Xin ◽  
孔亚飞 KONG Ya-fei ◽  
梅云辉 MEI Yun-hui ◽  
陆国权 LU Guo-quan
Keyword(s):  
High Temperature ◽  
High Power ◽  
Silver Paste ◽  
Nano Silver ◽  
Die Attach ◽  
High Power Led

New conductive thick-film paste based on silver nanopowder for high power and high temperature applications

2011 ◽  
Vol 51 (7) ◽  
pp. 1235-1240 ◽  
Author(s):  
Małgorzata Jakubowska ◽  
Mateusz Jarosz ◽  
Konrad Kiełbasinski ◽  
Anna Młożniak
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
High Power ◽  
Temperature Applications

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.

Investigation into the Role of Different Substrate Ni Compositions and Plating Methods on Die Attach Reliability

2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000073-000082
Author(s):  
Jinzi Cui ◽  
R. Wayne Johnson ◽  
Michael C. Hamilton
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
High Power ◽  
Diffusion Barrier ◽  
Die Attach ◽  
High Temperature Storage ◽  
The Impact ◽  
Direct Bond Copper ◽  
Temperature Storage

Nickel is a commonly used diffusion barrier for direct bond copper (DBC) substrates used in high temperature, high power applications. The Ni can be deposited by electroless or electrolytic plating and may be pure Ni, Ni:P, Ni:B or Ni:Co. The reactivity of these different Ni layers with AuGe and BiAgX® solder is explored. Specifically the reaction to form Ni-Ge intermetallics and NiBi3 during high temperature storage and the impact on die shear strength and failure mode are discussed.

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