Evaluation of High Temperature Joining Technologies for Semiconductor Die Attach

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000177-000192
Author(s):  
Siyuan Qi ◽  
Chris Powley ◽  
Maria Mirgkizoudi ◽  
Adele Pliscott ◽  
Peter Collier
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Thermal Cycling ◽  
Industrial Applications ◽  
Thermal Ageing ◽  
Conductive Adhesives ◽  
Similar Reduction ◽  
Initial Values ◽  
Die Attach ◽  
Reliability Performance

Abstract The development of novel high temperature die attach methods for semiconductor packaging enables use in harsh environments and unique opportunities for demanding industrial applications such as controls and monitoring for next generation engine and airframe platforms. Traditional die attach materials including lead solders and conductive adhesives cannot meet requirements of operation temperatures up to and exceeding 300°C due to their limited melting and glass transition temperatures [1]. The Manufacturing Technology Centre Ltd (MTC) has evaluated a range of high temperature die attach materials and processes for silicon and silicon carbide (SiC) semiconductors. Assembly processes were explored for bonding components with and without a back metallisation and with capability to support electrical back contact if required. Die attach methods evaluated include:Sinterable silver materials for back metallised semiconductor componentsSilver glass for non-back metallised semiconductor componentsGold-silicon near eutectic preforms for non-back metallised semiconductor components Two types of substrates were selected including high temperature co-fired ceramic (HTCC) packages and gold or silver plated Kovar substrates. Test assemblies were subjected to accelerated life tests consisting of thermal ageing at 400°C and thermal cycling of −40°C to 200°C. These tests enabled the evaluation of the die attach materials after accelerated conditions of use. Reliability performance of the die attach materials was assessed using visual and X-ray inspection, mechanical shear testing and microstructure analysis. For sinterable silver materials, the test assemblies constructed using HTCC packages showed no significant reduction in shear strength after 1,008 hours ageing at 400°C. However shear strengths of the test assemblies constructed using Kovar substrates reduced by 95% of the initial values after ageing at 400°C for 336 hours. All test assemblies showed no significant reduction in adhesion after thermal cycling of −40°C to 200°C for 1,000 cycles. In addition, no apparent differences in shear strengths could be detected for sintered silver interconnections for gold and silver metallised semiconductor components. Gold-silicon bonding as performed using a near eutectic preform had limited performance as aged at 400°C. Silver glass test assemblies constructed using HTCC packages showed a 50% reduction in shear strength compared to the initial values after thermal ageing at 400°C for 1,000 hours. A similar reduction in adhesion was presented after thermal cycling of −40°C to 200°C for 1,000 cycles.

Shear Strength and Thermomechanical Reliability of Sintered Ag Joints Containing low CTE Non-metal Additives for Die Attach

2018 ◽  
Vol 2018 (1) ◽  
pp. 000167-000172
Author(s):  
Guangyu Fan ◽  
Christine Labarbera ◽  
Ning-Cheng Lee ◽  
Colin Clark
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Thermal Cycling ◽  
Power Electronics ◽  
Metal Particles ◽  
Mechanical Reliability ◽  
Die Attach ◽  
Silver Sinter ◽  
Metal Additives ◽  
Sintered Silver

Abstract Ag sintering has been paid attention as an alternative to soldering in die attach for decades, especially for high temperature power electronics packages because of its high melting temperature, highly thermal and electrical conductivity of the sintered silver joints, and low process temperature less than 275°C. The coefficient of thermal expansion (CTE) of silver (19.1ppm/°C), however, is much higher than the silicon die (2.6ppm/°C) and the commonly used alumina substrate (7.2ppm/°C). CTE mismatch of the different materials in the various components in a power electronics package lead to the delamination at the interface between interconnection layer and chips or substrate, and/or cracking of the interconnection layer is one of the mostly common causes of failure of power electronics device during thermal cycling or high temperature operation. In recent years we have been developing a series of silver sinter pastes containing low CTE non-metal particles to reduce or adjust CTE of the sintered joints so as to extend the lifetime and reliability of power electronics device in high temperature applications. In the present paper, we will report a new set of silver sinter pastes containing micro scale non-metal particles, a sintering process, microstructural morphologies, thermo-mechanical reliability of the sintered joint and effect of the contents of non-metal particles on shear strength of the sintered silver joints bonding an Ag silicon die on Ni/Au DBC substrates. Shear tests on the sintered joints with and/or without the low CTE non-metal additives have been conducted at room temperature, 200, 250, and 300°C. Thermo-mechanical reliability of the sintered joints was evaluated by thermal cycling, thermal shock, high temperature storage tests (HTS), respectively. X-ray inspection and scanning electronic microscopy (SEM) were used to characterize void, crack and microstructure morphologies of the sintered joints with and/or without the additives.

ALUMINUM 1100

Alloy Digest ◽  
1974 ◽  
Vol 23 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Pure Aluminum ◽  
Heat Treating ◽  
Industrial Applications ◽  
Temperature Performance ◽  
Commercially Pure

Abstract ALUMINUM 1100 is commercially pure aluminum and is characterized by its excellent ability to be drawn, spun, stamped or forged. It has good weldability, excellent resistance to corrosion and many home, architectural and industrial applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-44. Producer or source: Various aluminum companies. Originally published October 1956, revised February 1974.

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.

LT-TLPS Die Attach for High Temperature Electronic Packaging

2014 ◽  
Vol 11 (1) ◽  
pp. 7-15
Author(s):  
Hannes Greve ◽  
F. Patrick McCluskey
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Melting Point ◽  
Low Temperature ◽  
Transient Liquid Phase ◽  
Liquid Phase Sintering ◽  
Die Attach ◽  
Metallic Interfaces ◽  
Dsc Analyses ◽  
Transient Liquid Phase Sintering

Low temperature transient liquid phase sintering (LT-TLPS) can be used to form high-temperature joints between metallic interfaces at low process temperatures. In this paper, process analyses and shear strength studies of paste-based approaches to LT-TLPS are presented. The process progression studies include DSC analyses and observations of intermetallic compound (IMC) formation by cross-sectioning. It was found that the sintering process reaches completion after sintering times of 15 min for process temperatures approximately 50°C above the melting point of the low temperature constituent. For the shear studies, test samples consisting of copper dice and copper substrates joined by sintering with a variety of sinter pastes with different ratios of copper and tin have been assessed. A fixture was designed for high temperature enabled shear tests at 25°C, 125°C, 250°C, 400°C, and 600°C. The influence of the ratio of the amount of high melting-point constituent to the amount of low melting-point constituent on the maximum application temperature of the sinter paste was analyzed. Ag20Sn and Cu50Sn pastes showed no reduction in shear strength up to 400°C, and Cu40Sn pastes showed high shear strengths up to 600°C. It was shown that LT-TLPS can be used to form high temperature stable joints at low temperatures without the need to apply pressure during processing.

High Temperature Bonding Effect of the Room-Temperature-Curing Phosphate Adhesive for C/C Composites

2016 ◽  
Vol 680 ◽  
pp. 179-183 ◽  
Author(s):  
Ming Chao Wang ◽  
Meng Meng Zhuang ◽  
Xin Tao ◽  
Xi Qing Xu ◽  
Hai Tao Geng ◽  
...  
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Thermal Cycling ◽  
Bonding Strength ◽  
Room Temperature ◽  
Temperature Range ◽  
Heat Resistant ◽  
Bonding Effect ◽  
Temperature Shear

A heat-resistant phosphate adhesive was developed for joining and repairing of C/C composites. The high-temperature bonding effect for both cured adhesive and 1300°C-calcined adhesive had been evaluated through testing high-temperature shear strength of corresponding joints. The results showed that the bonding strength of cured adhesive decreased from 7.9 MPa at RT to 0.9 MPa at 1300°C, while that of 1300°C-calcined adhesive could maintain about 4 MPa at temperature range from RT to 700°C and then decreased to 1.7 MPa at 1300°C. Besides, with the increasing thermal cycling times at 1300°C, the high-temperature bonding strength at this temperature could maintain at about 2.3 MPa.

Development of BiAgX® HT Solder Paste for 200°C Application

2016 ◽  
Vol 2016 (HiTEC) ◽  
pp. 000128-000133 ◽  
Author(s):  
Hongwen Zhang ◽  
Jonathan Minter ◽  
Ning-Cheng Lee
Keyword(s):  
Shear Strength ◽  
Thermal Cycling ◽  
Melting Temperature ◽  
Thermal Aging ◽  
Joint Strength ◽  
Solder Paste ◽  
Thermal Cycling Test ◽  
Cycling Test ◽  
Die Attach ◽  
Board Level

Abstract BiAgX® paste with the remelting temperature around 262°C has been tested and adopted successfully for die attach applications [1–5]. BiAgX® HT pastes with the enhanced remelting temperature above 265°C have been designed for the application of 200°C or even higher. The joint strength has been well maintained for most of the tested pastes after thermal aging @ 200°C for 1000hrs. The thermal cycling test (from −55°C to 200°C) degrades the bond shear strength but some of the tested pastes can still keep the joint strength well above IEC standard (IEC 60749-19) required. The melting temperature and the reliability have been observed to closely associate with the alloying elements Z%wt. The BiAgX® pastes have also been modified for board level assembly application. BiAgX® solder wire is under development too.

Reliability and Corrosion Resistance of High Temperature Lead-Free BiAgX™ Paste

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000347-000354 ◽  
Author(s):  
HongWen Zhang ◽  
RunSheng Mao ◽  
Ning-Cheng Lee ◽  
Satoshi Tanimoto
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Salt Water ◽  
Lead Free ◽  
Water Spray ◽  
Bond Shear Strength ◽  
Die Attach ◽  
Increasing Temperature ◽  
Average Bond

The BiAgX™ paste, designed for die attach application, composed of the majority of BiAg powders (melting point >260°C) and the minority of additive powders. The additive powders are dominating the interfacial reaction to improve the wetting of the paste on various commonly-used surface finish materials. After reflow, the joint shows the above 260°C remelting temperature. The average bond shear strength of BiAgX joint between SiC die and AMBC-SiN substrate (Package A) decreases from 54MPa to 16MPa with increasing temperature from RT to 250°C. Upon thermal storage at 200°C or 230°C for 3000hrs, the bond shear strength decreases from 54MPa to 38MPa and 21MPa, respectively. Upon thermal cycling from −55°C to 125°C for 2000cycles and thermal shock from −55°C to 150°C for 2000cycles, BiAgX outperforms Pb5Sn2.5Sn (Package B). BiAgX also show the better corrosion resistance than SAC305 and Pb5Sn2.5Ag under 96hrs salt water spray (SWS) tests.

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.

High temperature Au-based solder reliability in electronic packages for harsh environments

2011 ◽  
Vol 2011 (1) ◽  
pp. 000438-000445
Author(s):  
M.F. Sousa ◽  
S. Riches ◽  
C. Johnston ◽  
P.S. Grant
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Thermal Shock ◽  
Microstructural Analysis ◽  
Temperature Stability ◽  
Acoustic Microscopy ◽  
Harsh Environments ◽  
Electronic Packages ◽  
High Temperature Stability ◽  
Die Attach

The operation of electronic packages in high temperature environments is a significant challenge for the microelectronics industry, and poses a challenge to the traditional temperature limit of 125°C for high electronic systems, such as those used in down-hole, well-logging and aero-engine applications. The present work aims to develop understanding of how and why attach materials for Si dies degrade/fail under harsh environments by investigating high temperature Au based solders. Au-2wt%Si eutectic melts at < 400°C and offers high temperature stability but high temperature processing and complex manufacturing steps are the major drawbacks. Changes in the die attach material were investigated by isothermal ageing at 350°C, thermal shock and thermal cycling treatments. Die attach reliability investigated by thermal shock and thermal cycling showed that the bonded area degraded. Nevertheless, most of the samples tested had high bonded area ranging from 92.5 to 97.5%. The failure behaviour of the die attach materials included cracking of die and/or attach material, delamination and voiding. Scanning acoustic microscopy images provided a rapid assessment of delamination and other defects and their location within the package. Microstructural analysis and die shear testing were also carried out, along with the high temperature endurance of a SOI test chip for signal conditioning and processing applications at 250°C. All functions evaluated have shown stable performance at 250°C for up to 9000 hours.

Lead-Free Alternatives for Interconnects in High-Temperature Electronics

2017 ◽  
Author(s):  
Sandeep Mallampati ◽  
Liang Yin ◽  
David Shaddock ◽  
Harry Schoeller ◽  
Junghyun Cho
Keyword(s):  
Thermal Conductivity ◽  
Plastic Deformation ◽  
Shear Strength ◽  
High Temperature ◽  
Heat Dissipation ◽  
Volume Fraction ◽  
High Volume ◽  
Die Attach ◽  
Average Shear Strength ◽  
Average Shear

Predominant high melting point solders for high temperature and harsh environment electronics (operating temperatures from 200 to 250°C) are Pb-based systems, which are being subjected to RoHS regulations because of their toxic nature. In this study, high bismuth (Bi) alloy compositions with Bi-XSb-10Cu (X from 10 wt.% to 20 wt.%) were designed and developed to evaluate their potential as high-temperature, Pb-free replacements. Reflow processes were developed to make die-attach samples made out of the cast Bi alloys. In particular, die-attach joints made out of Bi-15Sb-10Cu alloy exhibited an average shear strength of 24 MPa, which is comparable to that of commercially available high Pb solders. These alloy compositions also retained original shear strength even after thermal shock between −55°C and +200°C and high temperature storage at 200°C. Brittle interfacial fracture sometimes occurred along the interfacial NiSb layer formed between Bi(Sb) matrix and Ni metallized surface. In addition, heat dissipation capabilities, using flash diffusivity, were measured on the die-attach assembly, compared to the corresponding bulk alloys. The thermal conductivity of all the Bi-Sb alloys was higher than that of pure Bi. By creating high volume fraction of precipitates in a die-attach joint microstructure, it was feasible to further increase thermal conductivity of this joint to 24 W/m·K, which is three times higher than that of pure Bi (8 W/m·K). Bi-15Sb-10Cu alloy has so far shown the most promising performance as a die-attach material for high temperature applications (operated over 200°C). Hence, this alloy was further studied to evaluate its potential for plastic deformation. Bi-15Sb-10Cu alloy has shown limited plastic deformation in room temperature tensile testing, in which premature fracture occurred via the cracks propagated on the (111) cleavage planes of rhombohedral crystal structure of the Bi(Sb) matrix. The same alloy has, however, shown up to 7% plastic strain under tension when tested at 175°C. The cleavage planes, which became oriented at smaller angles to the tensile stress, contributed to improved plasticity in the high temperature test.

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