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Light-emitting diode (LED) lamps, regarded as ‘green lighting’ fourth-generation light sources, are applied widely to many applications around us. Meanwhile, the chip-on Board (COB) packaging is a fatal important kind of packaging method for LED, with many advantages, such as bigger optical power, more compact size, loss manufacturing cost, and good reliability. However, low light extraction efficiency...
With the trend to be smaller, more integration and higher power in power electronic technology, the cooling problem has become increasingly prominent for those high power devices. Micro-channel in substrate, as an effective cooling method, has been proposed and investigated by many researchers in recent years. Warpage and stress, naturally existing in all the packaging processes due to the unavoidable...
To realize low temperature thermocompression bonding for 3D packaging and integration is of great significance. This research focuses on Cu-Cu low temperature thermocompression bonding using nanoporous copper films (NPCf) as bonding layer. Cu-Zn alloy as the precursor alloy was fabricated on the ceramic substrate by means of heating-alloy method, then the precursor alloy was immersed into the dilute...
Low temperature bonding technology has been a research hotspot in recent years due to its success of avoiding impurities interdiffusion, minimizing thermal stresses between heterogeneous materials, minimizing voids and other defects, and reducing the cost. In this work, a novel low temperature thermocompression bonding technology using nanoporous Cu (NPC) was proposed and the influences of different...
With the trend to be smaller, more integration and higher power in power electronic technology, the cooling problem has become increasingly prominent for those high power devices. Micro-channel in substrate, as an effective cooling method, has been proposed and investigated by many researchers in recent years. Warpage and stress, naturally existing in all the packaging processes due to the unavoidable...
Low temperature bonding technology has been a research hotspot in recent years due to its success of avoiding impurities interdiffusion, minimizing thermal stresses between heterogeneous materials, minimizing voids and other defects, and reducing the cost. In this work, a novel low temperature thermocompression bonding technology using nanoporous Cu (NPC) was proposed and the influences of different...
To realize low temperature thermocompression bonding for 3D packaging and integration is of great significance. This research focuses on Cu-Cu low temperature thermocompression bonding using nanoporous copper films (NPCf) as bonding layer. Cu-Zn alloy as the precursor alloy was fabricated on the ceramic substrate by means of heating-alloy method, then the precursor alloy was immersed into the dilute...
In this paper, a kind of heat spreader called direct plated copper ceramic spreader (DPC) is introduced. Different from the conventional ceramic spreaders, DPC manufacturing process includes thin film technology which increases the ability to make more accurate patterns and enables integrations in a larger scale. As a feature of the technology, electroplating was adopted to grow metal circuit layer,...
In this paper, the failure mechanisms of the direct bonding copper (DBC) substrate under the condition of temperature cycling are studied. The cyclic temperature considered ranges from −40°C to 200°C. Furthermore, finite element method is used to optimize the DBC substrate structure in order to reduce the thermal stress and improve the reliability and fatigue life of power modules. Various factors...
Due to its many advantages over traditional 3D packaging technology, through silicon via (TSVs) is being widely used. However, there are still a variety of obstacles hindering it from being developed rapidly. One of them is the huge thermal stress induced by big CTE mismatch between silicon and copper, which would even induce interfacial delamination. In this paper, thermal stress is evaluated first...
In this paper, a small flat-plate vapor chamber was developed to solve hotspot issue in high power electronic packages. The flat-plate vapor chamber was sealed by diffusion bonding technology and its porous wicks were fabricated by sintering copper powder. The transient and steady temperature distributions of the flat plate vapor chamber were experimentally measured. Its performance was compared with...
In order to obtain good welding quality, some influencing factors of reflow soldering process were studied in this research. A series of welding experiments were conducted in a small reflow soldering oven. Oxidation and surface treatment of soldering materials are important factors in the welding process. Temperature curve of reflow soldering has a great influence on the welding quality, and the welding...
Oxidation reaction, poor wettability and high peak temperature during reflow soldering will do harm to the electronic welding. In order to solve these problems, the welding performance in a nitrogen atmosphere was studied. Nitrogen atmosphere can improve the wettability of solder, reduce the degree of oxidation, and accelerate the welding speed of soldering reaction. A series of soldering experiments...
Light emitting diodes (LEDs) hold the promise for efficient, lightweight and environmental-friendly lighting sources, which is regarded as the next-generation lighting technology. Since so many problems still remain to be solved, this emerging technology has attracted the attention of a large number of researchers. Among several issues frequently discussed in the community, the long-time reliability...
Thick-film pressure sensors on steel substrate are proven to be robust and low cost, and can be used in many fields such as automotive industries, oil industries and military sectors. In this paper, finite element method (FEM) was used to evaluate residual thermal stresses and the self-heating of the thick film resistors (TFRs) on the offset voltage of the sensor. Results show that the residual stresses...
As the market is desperate for better performed, miniaturized, highreliableand lower-priced electronic devices, nowadays, three dimensional integrated circuit (3D IC) seems to be a promising technology which can meet these requirements. However, many issues hinder this technology from being developedrapidly, among which the reliability of through silicon via(TSV) is one of the major concerns. Because...
In this paper, experiments were carried out to confirm that Copper layer was a feasible masking material during the wet etching process of Pyrex glass for vacuum packaging or 3D packaging. Our study revealed that the sputtered Chromium and Copper layers combination with the electroplated Copper layer is an ideal etching mask. The improvement of the corrosion solution produced some more reliable results...
As the most promising candidate for the realization of high-efficiency light sources for general lighting, the high power lighting emitting diodes (LEDs) still have reliability issues that hinder the large scale application of LED devices. Nowadays, the reliability is becoming an essential barrier for LED devices to substitute the traditional light sources. Before it is applied into mass production,...
Through silicon via (TSV) is an emerging technology for MEMS packaging for MEMS packaging. 370µm deep TSV vias with diameter of 60µm were filled by bottom up copper electroplating with copper methylsulfonate and methane sulfonic acid as base electrolyte. Insulating layer of the wafer was silicon nitride deposited by LPCVD. The TSV vias filling processes include electroplating to fill the vias and...
In this study, the thermal resistance of a typical LED package was analyzed and a compact thermal model (CTM) was obtained by considering the configuration of each layer of LED package. The building of the CTM was presented in detail. Experiments and finite element simulations were conducted to validate the CTM. The error of the thermal resistance obtained by the CTM and simulations were less than...
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