Parametric study of electronics components joining using reactive films for high temperature applications

2019 ◽  
Vol 2019 (HiTen) ◽  
pp. 000016-000021
Author(s):  
Rabih Khazaka ◽  
Donatien Martineau ◽  
Toni Youssef ◽  
Thanh Long Le ◽  
Stéphane Azzopardi

Abstract In this paper, in order to assemble electronic components onto substrates, a local rapid soldering process using an exothermic reactive foil sandwiched between solder preforms was evaluated. Among others, the main interest of this technique is that it can allow the use of high temperature melting solders, without the need to heat the whole assembly above this melting temperature. The reactive foil is commercially available and is formed from alternatively stacked nanolayers of Ni and Al until it reaches the total film thickness. Once the film is activated by using an external power source, a reaction takes place and releases such an amount of energy that is transferred to the solder preforms. If this amount of energy is high enough, solder preforms melt and insure the adhesion between the materials of the assembly. The process was evaluated using a standard SAC305 and a high temperature Au80Sn20 preforms. The influences of the applied pressure, the reactive film thickness as well as the solder and the attached materials nature and thicknesses were investigated. The initial joint quality was evaluated using scanning acoustic microscopy, scanning electron microscopy, and shear strength measurements. It was shown that the applied pressure during the process has a strong effect on the joint initial quality. The voids ratio between metallized diode dice and an Active Metal Braze (AMB) substrate decreases from 64% to 26% for pressure values between 0.5kPa and 100kPa respectively. Otherwise, under a constant low pressure of 13kPa, reducing the substrate metal thickness on a low thermal conductivity insulator allows the improvement of the initial joint quality and a voids ratio of about 15% was reached when using 35μm of copper on FR4 substrate. The use of aluminum instead of copper as a metal for the ceramic metallized substrate (with the same gold finishing layer) led to a reduction in the void ratio in the joint. The microstructure of the AuSn joint achieved using the reactive films shows very fine phase distribution compared to the one obtained using conventional solder reflow process in the oven. The mechanical properties of the joint were evaluated using shear tests performed on 350μm thick silicon diodes assembled on AMB substrates under a pressure of 100kPa. The reactive films were 60μm thick and were sandwiched between two 25μm thick SAC preforms. The void ratio was about 37% for the tested samples and shear strength values above 9.5MPa were achieved which remains largely higher than MIL-STD-883H requirements. Finally, the process impact on the electrical properties of the assembled diodes was compared with a commonly used solder reflow assembly and results show a negligible variation.

2019 ◽  
Vol 16 (4) ◽  
pp. 182-187
Author(s):  
Rabih Khazaka ◽  
Donatien Martineau ◽  
Toni Youssef ◽  
Thanh Long Le ◽  
Stéphane Azzopardi

Abstract The rapid and localized heating techniques allow the joining of temperature-sensitive materials and components without thermal induced damage commonly encountered when high-temperature solder reflow processes are used. This is also advantageous for making assemblies with materials having a large difference in the coefficient of thermal expansion without induced bowing or cracking. The use of exothermic reactive foil sandwiched between solder preforms is a promising local and rapid soldering process because it does not require any external heat source. The reactive foil is formed from alternatively stacked nanolayers of Ni and Al until it reaches the total film thickness. Once the film is activated by using an external power source, a reaction takes place and releases such an amount of energy that is transferred to the solder preforms. If this amount of energy is high enough, solder preforms melt and insure the adhesion between the materials of the assembly. The influences of the applied pressure, the reactive film (RF) thickness as well as the solder, and the attached materials chemical composition and thickness were investigated. It was shown that the applied pressure during the process has a strong effect on the joint initial quality with voids ratio decreases from 64% to 26% for pressure values between .5 and 100 kPa, respectively. This can be explained by the improvement of the solder flow under higher pressure leading to a better surface wettability and voids elimination. Otherwise, the joint quality was found to be improved once the solder melting duration is increased. This relationship was observed when the thickness of the reactive foil is increased (additional induced energy) or the thickness of solders, Cu, and/or Si is decreased (less energy consumption). The microstructure of the AuSn joint achieved using the RFs shows very fine phase distribution compared with the one obtained using conventional solder reflow process in the oven because of high cooling rate. The mechanical properties of the joint were evaluated using shear tests performed on 350-μm-thick silicon diodes assembled on active metal brazed substrates under a pressure of 100 kPa. The RFs were 60 μm thick and sandwiched between two 25-μm-thick 96.5Sn3Ag.5Cu (SAC) preforms. The voids ratio was about 37% for the tested samples and shear strength values above 9.5 MPa were achieved which remains largely higher than MIL-STD-883H requirements. Finally, the process impact on the electrical properties of the assembled diodes was compared with a commonly used solder reflow assembly and the results show a negligible variation.


2015 ◽  
Vol 2015 (1) ◽  
pp. 000449-000452 ◽  
Author(s):  
Xiangdong Liu ◽  
Hiroshi Nishikawa

We develop a transient liquid phase sinter (TLPS) bonding using Sn-coated Cu micro-sized particles. With this bonding process, a thermally stable joint comprising Cu3Sn phase and a dispersion of ductile Cu particles can be obtained. The particle paste, which contained Cu particles with a thin Sn coating and terpineol, was used to join Cu substrates. The setup was bonded at 300 °C for 30s under an applied pressure of 10 MPa using a thermo-compression bonding system under a formic acid gas atmosphere for reducing the oxide layer on the Sn coating and the Cu substrate. After bonding, the TLPS joint showed a thermally stable microstructure with a good shear strength, which was fully consisted of Cu3Sn intermetallic compounds matrix and embedded ductile Cu particles. The kinetics of the microstructure transformation and high temperature reliability of the TLPS joint were investigated. After 300 °C isothermal aging for 200h, the shear strength and microstructure of the TLPS joints showed almost unchanged. The results demonstrate that joint with high-melting-point obtained by the TLPS bonding using Sn-coated Cu particle paste has the potential to fulfill the requirement of high temperature electronic packaging.


2018 ◽  
Vol 2018 (1) ◽  
pp. 000434-000441
Author(s):  
Ly May Chew ◽  
Wolfgang Schmitt

Abstract Silver sintering is a promising die attach technology for high temperature power electronics packaging. Our previous studies have revealed that highly reliable sintered joints was obtained on silver and gold surfaces by either non-pressure or pressure sintering. In this paper, we extended our study to die attachment on copper surfaces by pressure sintering under air atmosphere. We attached Ag metallized die on silicon nitride active metal braze copper substrates with Ag metallization and without metallization by silver sintering at 230°C with a pressure of 10 MPa for 3 min. We observed that the average initial die shear strength for bare Cu substrate is lower than for Ag metallized substrate. This observation is attributed to the self-diffusion of Ag is faster than the interdiffusion between Ag and Cu. However, the average die shear strength for all samples increased considerably after temperature cycling test (−40°C/+150°C) and high temperature storage at 250°C. It is highly likely that sintering process is not yet completed under the sintering conditions used in this study and consequently Ag and Cu continued to diffuse during thermal cycling and high temperature storage and as a result strengthen the sintered joints. It is believed that after a certain time of storage at 250°C the sintering process is completed as we observed the average die shear strength remained relatively constant after 250 h storage. Voids, drying channels and delamination in the sintered joints were not detected by scanning acoustic microscopy for the samples before and after 2000 thermal cycles.


2013 ◽  
Vol 58 (2) ◽  
pp. 529-533 ◽  
Author(s):  
R. Koleňák ◽  
M. Martinkovič ◽  
M. Koleňáková

The work is devoted to the study of shear strength of soldered joints fabricated by use of high-temperature solders of types Bi-11Ag, Au-20Sn, Sn-5Sb, Zn-4Al, Pb-5Sn, and Pb-10Sn. The shear strength was determined on metallic substrates made of Cu, Ni, and Ag. The strength of joints fabricated by use of flux and that of joints fabricated by use of ultrasonic activation without flux was compared. The obtained results have shown that in case of soldering by use of ultrasound (UT), higher shear strength of soldered joints was achieved with most solders. The highest shear strength by use of UT was achieved with an Au-20Sn joint fabricated on copper, namely up to 195 MPa. The lowest average values were achieved with Pb-based solders (Pb-5Sn and Pb-10Sn). The shear strength values of these solders used on Cu substrate varied from 24 to 27 MPa. DSC analysis was performed to determine the melting interval of lead-free solders.


Alloy Digest ◽  
1962 ◽  
Vol 11 (3) ◽  

Abstract ALUMINUM 220 is a 10% magnesium-aluminum casting alloy having the highest combination of mechanical properties, corrosion resistance and machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-112. Producer or source: Aluminum Company of America.


Alloy Digest ◽  
1978 ◽  
Vol 27 (12) ◽  

Abstract ALUMINUM 2011 is an age-hardenable aluminum-copper alloy to which lead and bismuth are added to make it a free-machining alloy. It has good mechanical properties and was designed primarily for the manufacture of screw-machine products. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-32. Producer or source: Various aluminum companies. Originally published October 1955, revised December 1978.


Alloy Digest ◽  
1990 ◽  
Vol 39 (7) ◽  

Abstract ULTEM 6100 and 6200 are glass reinforced and ULTEM 6202 is a mineral filled copolymer resin. For properties of the unreinforced resin, ULTEM 6000, see Alloy Digest P-27, June 1991. These are high temperature materials that are particularly suitable for military electrical components which must survive 200 C testing. This datasheet provides information on physical properties, hardness, tensile properties, and compressive and shear strength as well as fracture toughness. It also includes information on corrosion resistance. Filing Code: Cp-16. Producer or source: G. E. Plastics.


Alloy Digest ◽  
1974 ◽  
Vol 23 (2) ◽  

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.


Alloy Digest ◽  
1974 ◽  
Vol 23 (4) ◽  

Abstract ALUMINUM 3004 is nominally an aluminum-manganese-magnesium alloy which cannot be hardened by heat treatment; however, it can be strain hardened by cold working. It has higher strength than Aluminum 3003 and good workability, weldability and resistance to corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive 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-51. Producer or source: Various aluminum companies. Originally published June 1957, revised April 1974.


Alloy Digest ◽  
1975 ◽  
Vol 24 (12) ◽  

Abstract Copper Alloy NO. 182 is an age-hardening type of alloy that combines relatively high electrical conductivity with good strength and hardness. It was formerly known as Chromium Copper and its applications include such uses as resistance-welding-machine electrodes, switch contacts and cable connectors. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-305. Producer or source: Copper and copper alloy mills.


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