Refine
Labor/Institute
- BIOMEMS Lab (1)
Keywords
- Lötverbindung (3)
- Lumineszenzdiode (2)
- Löten (2)
- Akkumulator (1)
- Aushärtung (1)
- Biologisch abbaubarer Kunststoff (1)
- Buckelschweißen (1)
- Computertomografie (1)
- Computertomographie (1)
- Differential scanning calorimetry (1)
Document Type
- Article (10)
- Conference Proceeding (1)
Reviewed
- ja (1)
Ecological comparison of soldering and sintering as die-attach technologies in power electronics
(2015)
In this study the method of life cycle assessment is used to perform a comparison of two die-attach technologies of power modules: silver sintering and common soldering with a tin–silver–copper solder. The goal of the study is to indicate which die-attach technique is more environmentally friendly. This is important in order to design future electronics more environmentally friendly.
Processing covers the manufacturing of the respective pastes, application of pastes, and mounting as well as the subsequent sintering or soldering, including cleaning of the soldered parts. The last step in the processing is a wire bonding process. The environmental impacts are expressed in CO2-equivalents and ReCiPe points and different variants are discussed: comparisons are made between considered pastes and between a soldered and a sintered power module, including consideration of lifetime. Concerning sintering, the influence of using recycled silver is analyzed more closely. The types of stages included in this life cycle assessment best fit a cradle-to-gate assessment, because usage, recycling, and disposal are not included. The software used is OpenLCA version 1.3.3, created by GreenDelta, and the database used is Ecoinvent version 2.2. In order to fill data gaps, electronics manufacturing companies were contacted, and our own calculations and measurements were applied.
The consideration of the wet film thicknesses of the soldering system and sintering system, respectively, results in very similar CO2-equivalent emissions for sinter paste and solder paste. Comparing the soldered power module to the sintered one shows minor to significant differences between the two systems which could easily be changed when changing circumstances and assumptions. But when considering the respective lifetimes of the joining technologies, sintering technology is clearly preferable to the conventional soldering technology. Using solely recycled silver for manufacturing of silver sinter paste reduces the CO2-equivalent emissions of one sintered power module by roughly 40%.
The results clearly show the dependence of outcomes on the initial settings. Consideration of lifetime has an enormous impact on the comparison of soldering technology to sintering technology. But the benefit of this life extension through the use of sintering technology is only useful when a long lifetime is required.
In recent years, the demand for sustainable and degradable materials and electronic devices has increased significantly.
Among a range of biodegradable polymers, poly(lactic acid) (PLA) is a good alternative to conventional petrol-based polymers because of its attractive mechanical properties and its easy processability. Recently, PLA has also been described as a promising dielectric material with piezoelectric and electret properties. We expect that PLA—after further optimization— will play an important role as a material for environmentally friendly sensors in the future, where first applications such as air filters and pressure sensors have already been proposed. However, degradation under normal ambient conditions is very slow, and an accelerated and controllable degradation process is highly desirable for any type of PLA-based sensors.
Enzymatic hydrolysis with embedded enzymes has been proposed as an approach to accelerate and control degradation. In this work, we investigate the properties of PLA in terms of dielectric and mechanical properties with a focus on its ability to store charges after the enzyme proteinase K (Trit. album) has been incorporated. Results reveal that proteinase K has a positive effect on the charge stability of solvent-cast PLA electrets after complete evaporation of the solvent. Furthermore, we observed a concentration-dependent acceleration of mass loss in a Tris-HCl buffer. A fast degradation within only one day occurred at a concentration of 6 wt% proteinase K.