On May 3, OSRAM, a large German lighting manufacturer, released the performance report for the second quarter of fiscal 2017. From January to March 2017, it achieved a revenue of 1.05 billion euros (equivalent to 7.897 billion yuan), an increase of about 10% over the same period of last year. Today, with the rapid development of semiconductor lighting, the key problem of LED - heat dissipation will become a big problem. So how can Z high-efficiency heat dissipation be achieved? Today, let's talk about the key point of LED cooling - chip.

　　Nowadays, the manufacturing of chips is diverse, and LED chips are no exception. The thermal conductivity of the chip will directly affect the heat dissipation. Of course, as a chip, we can't just look at the heat dissipation, as well as the dielectric constant and thermal expansion coefficient. Today, the widely used aluminum substrate in the market is compared with the low-key ceramic substrate.

　　Aluminum substrate -- common in LED lighting products. There are positive and negative sides. The white side is welded with LED pins, and the other side presents the natural color of aluminum. Generally, it will be in contact with the heat conduction part after coating the heat conduction slurry.

　　The commonly used metal aluminum based plates for aluminum substrate mainly include 1000 series, 5000 Series and 6000 series. The basic characteristics of these three series of aluminum materials are as follows:

　　1. 1000 series represents 1050, 1060 and 10701000 series aluminum plates, also known as pure aluminum plates. Among all series, 1000 series has more aluminum content Z, and the purity can reach more than 99.00%. Because it does not contain other technical elements, the production process is relatively simple and the price is relatively cheap. It is a series commonly used in conventional industry at present.

　　2. 5000 series represents 5052, 5005, 5083 and 5A05 series. 5000 series aluminum plate belongs to the commonly used alloy aluminum plate series. The main element is magnesium, with a magnesium content of 3-5%, which is also known as aluminum magnesium alloy. The main features are low density, high tensile strength and high elongation. Under the same area, the weight of aluminum magnesium alloy is lower than that of other series, so it is often used in aviation, such as aircraft fuel tank.

　　3. 6000 series represents 6061, which mainly contains magnesium and silicon, so it integrates the advantages of 4000 series and 5000 series. 6061 is a cold-treated aluminum forging product, which is suitable for applications with high requirements for corrosion resistance and oxidation. Good usability, excellent interface characteristics, easy coating and good processability.

　　The thermal conductivity of 5000 series aluminum substrate is about 135w / (m · K), 6000 series is about 150W / (m · K), and 1000 series is about 220W / (m · K).

　　Next, let's look at the ceramic substrate.

　　Ceramic substrate refers to a special process plate in which copper foil is directly bonded to the surface (one or both sides) of alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate at high temperature. The ultra-thin composite substrate has excellent electrical insulation performance, high thermal conductivity, excellent solderability and high adhesion strength. It can etch various patterns like PCB and has great current carrying capacity.

　　Ceramic circuit boards have the following characteristics:

　　◆ strong mechanical stress and stable shape; High strength, high thermal conductivity and high insulation; Strong adhesion and anti-corrosion.

　　◆ excellent thermal cycle performance, with 50000 cycles and high reliability.

　　◆ like PCB board (or IMS substrate), it can etch the structure of various graphics; No pollution and pollution.

　　◆ operating temperature range: - 55 ℃ ~ 850 ℃; The coefficient of thermal expansion is close to silicon, which simplifies the production process of power module. It can save Mo sheet of transition layer, save labor, save materials and reduce cost;

　　◆ reduce welding layer, reduce thermal resistance, reduce cavity and improve yield;

　　◆ under the same current carrying capacity, the line width of 0.3mm thick copper foil is only 10% of that of ordinary printed circuit board;

　　◆ excellent thermal conductivity makes the package of the chip very compact, which greatly improves the power density and improves the reliability of the system and device;

　　◆ ultra thin (0.25mm) ceramic substrate can replace BeO without environmental toxicity;

　　◆ large current carrying capacity, 100A current continuously passes through 1mm wide and 0.3mm thick copper body, and the temperature rise is about 17 ℃; 100A current continuously passes through 2mm wide and 0.3mm thick copper body, and the temperature rise is only about 5 ℃;

　　◆ low thermal resistance, 10 × The thermal resistance of 10mm ceramic substrate is 0.63mm, 0.31k/w, 0.38mm and 0.14k/w respectively.

　　◆ high insulation and withstand voltage to ensure personal safety and equipment protection ability.

　　◆ new packaging and assembly methods can be realized to make the products highly integrated and reduce the volume.

　　AIN ceramic plate has ultra-high thermal conductivity, the theoretical thermal conductivity at room temperature is 319w / (m · K), and good insulation. The resistivity is greater than 1014 Ω· cm at 25 ℃.

　　The advent of ceramic substrate products has opened the development of heat dissipation application industry. Due to the heat dissipation characteristics of ceramic substrate and the advantages of ceramic substrate such as high heat dissipation, low thermal resistance, long service life and voltage resistance, with the improvement of production technology and equipment, the rationalization of product prices has accelerated, so as to expand the application fields of LED industry, such as indicator lights of household electrical products, car lights, street lights and large outdoor kanban. The successful development of ceramic substrate will provide services for indoor lighting and outdoor lighting products, and expand the market field of LED industry in the future.

　　After comparison, we believe that we have a certain understanding of the substrates of the two materials. With the renewal and iteration of technology, new and better products will replace the old technology. The market has always been the survival of the fittest. As a manufacturer, we should compete healthily to make our products better and better, so as to drive the progress and take-off of the whole industry.