Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment

Li, Jian Feng; Agyakwa, Pearl; Johnson, C.M.

doi:10.1007/s11664-013-2971-7

Cited by 25 publications

(8 citation statements)

References 27 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A concern on SLID joints is the intermetallic compound (IMC) region formed when the molten phase is consumed during bonding. Although the mechanical properties of IMC joints can be improved through post-heat treatments [7,8], the formation of pores is an issue. Ga and In had also been used in SLID designs due to its low melting temperature.…”

Section: Introductionmentioning

confidence: 99%

Low-pressure solid-state bonding technology using fine-grained silver foils for high-temperature electronics

Lee

2017

J Mater Sci

View full text Add to dashboard Cite

A solid-state bonding technique using fine-grained silver (Ag) foils is presented. The Ag foils are manufactured using many runs of cold rolling and subsequent annealing processes to achieve the favorable microstructure. X-ray diffraction and pole figure measurement are performed to examine the crystal structure and grain orientations. Si chips are bonded to bare Cu substrates using the Ag foil as the bonding medium at 300°C in 0.1 torr vacuum assisted by 6.9 MPa static pressure, which is much lower than that used in conventional thermal compression bonding. Cross sections prepared by focus ion beam show clear bonding interfaces with only a few voids smaller than 100 nm. The bonded structures do not crack after cooling down to room temperature, indicating that the ductile Ag layer is able to manage the strain induced by the large coefficient of thermal expansion mismatch between Si and Cu. The average shear strength of as-bonded samples is 29 MPa. High-temperature storage tests are conducted, and slight increase in strength can be observed after 300°C aging. Fracture analyses show that the breakage occurs within the Ag foil rather than on the bonding interface. Transmission electron microscopy and energydispersive spectroscopy (TEM/EDX) are conducted for Ag/Cu interface after 200-h aging, and the result shows that slight diffusion proceeds during the aging. Since Ag has the highest electrical and thermal conductivities among metals, therefore the bonded structures reported in this paper probably represent the best possible design for high-temperature and high-power electronic packaging applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Low-pressure solid-state bonding technology using fine-grained silver foils for high-temperature electronics

Lee

2017

J Mater Sci

View full text Add to dashboard Cite

show abstract

“…Effort has also been devoted to characterization of TLP bonded chips to metallic substrate materials when a high mismatch between the coefficients of thermal expansion (CTE) strongly affects the microstructural, [24][25][26] mechanical, [27][28][29] or electrical properties 30 after processing, annealing, or thermal cycling.…”

Section: Introductionmentioning

confidence: 99%

Effect of Process and Service Conditions on TLP-Bonded Components with (Ag,Ni–)Sn Interlayer Combinations

Lis

Leinenbach

2015

Journal of Elec Materi

View full text Add to dashboard Cite

Transient liquid phase (TLP) bonding of Cu substrates was conducted with interlayer systems with the stacking sequences Ag-Sn-Ag (samples A), Ni-Sn-Ni (samples B), and combined Ag-Sn-Ni (samples C). Because of the low mismatch of the coefficients of thermal expansion, characteristics of the TLP process and mechanical and thermal behavior of TLP-bonded samples could be investigated without interference from thermally induced residual stresses. An ideal process temperature of 300°C, at which the number of pores was lowest, was identified for all three layer systems. It was verified experimentally that formation of pores resulted from volume contraction during isothermal solidification of liquid Sn into intermetallic compounds (IMC). Temperature and interlayer-dependent growth characteristics of IMC accounted for the increasing size and number of defects with increasing process temperature and for different defect positions. The shear strength was measured to be 60.4 MPa, 27.4 MPa, and 40.7 MPa for samples A, B, and C, respectively, and ductile fracture features were observed for Ag 3 Sn IMC compared with the purely brittle behavior of Ni 3 Sn 4 IMC. Excellent thermal stability for all three layer systems was confirmed during long-term annealing at 200°C for up to 1200 h, whereas at 300°C the microstructure was driven toward Ag-Sn solid solution, accompanied by Cu diffusion from the substrate along grain boundaries and Cu 3 Sn IMC formation (A), and toward Ni-rich IMC phases (B). Combined IMC interlayers (C) tended to be transformed into Ni-based IMC when held at 300°C; intermixing into (Ni,Cu) 3 Sn was accompanied by pore formation.

show abstract

“…This result could indicate that Ag was not completely consumed during the reactive alloying even after being stored for over three months. Such surface morphological characterization together with the resistance stability tests indicate that LM-LAg-SBS has a [39,40] with the precipitation of Ga particles. The broad peak centered at ≈34.3° comes from Ga (PDF# 27 0222), while the peaks located at 38.4°, 55.5°, 65.1°, 69.6°, 78.2° very closely indicate as-formed In 4 Ag 9 (PDF# 29 0678).…”

Section: Resultsmentioning

confidence: 87%

“…The inset picture schematically illustrated the reacting wetting process. Once contacting LAg-SBS, LM can alloy with Ag and form LM-lyophilic intermetallic compounds[39,40] with the precipitation of Ga particles. The broad peak centered at ≈34.3° comes from Ga (PDF# 27 0222), while the peaks located at 38.4°, 55.5°, 65.1°, 69.6°, 78.2° very closely indicate as-formed In 4 Ag 9 (PDF# 29 0678).…”

mentioning

confidence: 99%

Liquid–Metal‐Superlyophilic and Conductivity–Strain‐Enhancing Scaffold for Permeable Superelastic Conductors

Zhuang

Gao

et al. 2021

Adv Funct Materials

View full text Add to dashboard Cite

Liquid metal (LM) has recently been used as an advanced stretchable material for constructing stretchable and wearable electronics. However, due to the poor wettability of LM and the large dimensional change during stretching, it remains very challenging to obtain a high conductivity with minimum resistance increase over large tensile strains. To address the challenge, an LM‐superlyophilic and stretchable fibrous thin‐film scaffold is reported, on which LM can be readily coated or printed to form permeable superelastic conductors. In contrast to conventional LM‐based conductors where LM particles are filled into an elastic matrix or printed on the surface of an elastic thin film, the LM can quickly infuse into the LM‐superlyophilic scaffold and form bi‐continuous phases. The LM‐superlyophilic scaffold shows unprecedented advantages of an extremely high uptake of the LM and a conductivity‐enhancement characteristic when stretched. As a result, the LM‐based conductor displays and ultrahigh conductivity of 155 900 S cm−1 and a marginal resistance change by only 2.5 fold at 2 500% strain. The conductor also possesses a remarkable durability over a period of 220 000 cycles of stretching tests. The printing of LM onto the LM‐superlyophilic scaffold for the fabrication of various permeable and wearable electronic devices is demonstrated.

show abstract

Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment

Cited by 25 publications

References 27 publications

Low-pressure solid-state bonding technology using fine-grained silver foils for high-temperature electronics

Low-pressure solid-state bonding technology using fine-grained silver foils for high-temperature electronics

Effect of Process and Service Conditions on TLP-Bonded Components with (Ag,Ni–)Sn Interlayer Combinations

Liquid–Metal‐Superlyophilic and Conductivity–Strain‐Enhancing Scaffold for Permeable Superelastic Conductors

Contact Info

Product

Resources

About