With the improvement of IC (Integrated Circuits) chip design level and manufacturing technology, SMT (Surface Mounting Technology) is developing towards high density, high reliability and miniaturization, so it also challenges the traditional welding methods. Soldering will become a new weapon in the field of welding. At present, QFP (Quad Flat Package) pin center distance has reached 0.3mm, the number of pins of a single device can reach more than 576. This makes the traditional welding methods such as traditional gas phase reflow welding, hot air reflow welding, and infrared reflow welding very easy to "bridge" adjacent lead solder joints when welding such fine-pitch components.
In addition, in the field of traditional wire welding, the advancement of IC technology has promoted the development of wire processing technology and technology from the other side. For example, in the field of traditional connectors, the further miniaturization of PCB and terminal sizes makes the traditional hot bar soldering and soldering iron soldering process bottlenecks. In addition, due to contact welding processes such as traditional HOT BAR welding and electric iron welding, there is a potential danger to the wire and transmission performance. In areas where the quality and rate of wire transmission are high, manufacturers try to avoid using these methods for welding.
At the same time, the emergence of some new MEMS devices, such as mobile phone camera modules, has made the soldering of electronic components out of the traditional concept of planar welding, and has developed in the direction of three-dimensional welding. For such devices, contact processing methods such as electric soldering iron are prone to interference, and non-contact and high-precision processing methods are required.
Therefore, more and more people are researching new welding. Among them, laser soldering technology, due to its unique heat source properties, extremely small spot size, and local heating characteristics, has helped to solve such problems to a large extent. Therefore, it has also attracted more and more attention from manufacturers.
Generally speaking, laser soldering has the following advantages: high laser processing accuracy, light spot can reach micron level, process time program control, accuracy is much higher than traditional methods; non-contact processing, there is no contact welding The resulting stress; a small laser beam replaces the iron tip, which is also easy to process when there are other interferences on the surface of the workpiece; local heating, small heat affected zone; no static threat; laser is the cleanest processing method, no consumables, Simple maintenance and easy operation. Can be processed after assembling double-sided components on double-sided printed circuit boards; good repeatability, low contamination of welding tools by solder, easy control of laser irradiation time and output power, high laser brazing yield; easy implementation of laser beams Beam splitting, which can be divided into time and space using optical elements such as half-lenses, mirrors, prisms, and scanning mirrors, and can achieve simultaneous and symmetrical welding at multiple points; when using YAG laser or semiconductor laser as a heat source, it can be transmitted using optical fibers, so it can not be easily done in conventional ways The welding position is processed with good flexibility; the focus is good, and it is easy to realize the automation of the multi-station device.
Principle of laser soldering
Laser soldering is a type of laser processing. Laser processing is to irradiate a laser beam onto the surface of a processing object to remove or melt materials and change the surface properties of the object to achieve processing. Therefore, it is a non-contact processing. Its main features are small deformation of the workpiece, small heat affected zone, no inertia, noise, and fast processing speed. Because the energy of the beam and the speed of the beam can be adjusted, various processing purposes can be achieved.
Laser soldering uses laser as a heating source to radiantly heat leads (or connection pads of leadless devices) and transfer heat to the substrate through solder paste (or pre-made solder pieces). When the temperature reaches the soldering temperature, the solder paste melts , The substrate and the lead are wetted by the solder to form a solder joint.
The application of lead-free solder brings great challenges to the electronic assembly process
Sn-Pb solder has been reused by people, and it is also the most widely used material in electronic assembly technology. This is because of its lower melting temperature, good electrical conductivity, excellent mechanical properties, metallurgical properties and solderability, and low cost. The cost is inseparable. The Sn-Pb solder contains Pb, Pb and its compounds are very toxic and cause great harm to humans and the environment. The Sn-Pb alloy solder, which is widely used in the electronics industry, is one of the important sources of pollution. With the increasing awareness of human environmental protection, the development of environmentally friendly lead-free solder has become an urgent issue in the field of soldering and electronic assembly. In addition, due to poor shear strength, creep resistance, and thermal fatigue resistance of traditional Sn-Pb solders, solder joints are liable to fail prematurely during service. This limitation of the Sn-Pb solder is more apparent in the surface-mount structure, because compared with the through-hole insertion technology, the surface-mount solder joint directly bears the device and the printed circuit board due to the inflexible pins. Due to thermal expansion coefficient mismatch.
Lead-free poses challenges to traditional electronic assembly processes. Compared with the assembly technology using traditional Sn-Pb solder, lead-free electronic assembly technology has the following two basic characteristics:
(1) The lead-free solder widely used currently has a melting point of about 220 ° C, which is 30 ~ 40 ° C higher than that of traditional Sn-Pb solder. To ensure that the solder has good wettability after melting, general requirements The peak soldering temperature is 20-40 ° C higher than the melting point, which results in a peak soldering temperature of about 250 ° C after lead-free. The reflow welding process curve changes accordingly, and the preheating temperature and the peak temperature of reflow welding increase accordingly. As a result, higher requirements have been imposed on the heat resistance of electronic assembly equipment, electronic components and printed circuit boards.
(2) The wettability of almost all lead-free solders is weaker than that of traditional Sn-Pb solders. In addition, the high temperature oxidizes the pads and lead-free solders with high Sn content, which easily leads to solder joint wetting. Poor, resulting in many post-weld defects, affecting the quality and reliability of the solder joint. The high temperature required for the melting of lead-free solder can be solved by increasing the heating temperature of the wave soldering or reflow soldering equipment. However, the problems of poor solder wetting and easy oxidation caused by high temperature are a big challenge for the electronics assembly industry:
a) After soldering with lead-free solder, the surface of the solder joint is severely oxidized;
b) In the lead-free assembly process, when the solder is brazed in an air atmosphere, the wetting angle of the molten solder is large, the wetting force is reduced, the fillet transition is not smooth, and the probability of voids is increased;
c) Compared with the traditional Sn-Pb solders, lead-free solders have a wide range of types, and their performances are very different, and their surface assembly processes are also very different. Compared with traditional Hot Bar soldering and soldering iron soldering, laser soldering has the following advantages:
a) The laser processing accuracy is high, the light spot can reach the micron level, the processing time is program controlled, and the accuracy is much higher than the traditional process;
b) non-contact processing, there is no stress caused by contact welding;
c) The small laser beam replaces the iron tip, and it is also easy to process when there are other interferences on the surface of the workpiece;
d) local heating, small heat affected zone;
e) no static threat;
f) Laser is the cleanest processing method, no consumables, simple maintenance and easy operation;
g) When YAG laser or semiconductor laser is used as the heat source, it can be transmitted by optical fiber, so it can be processed in the place where welding is not easy in the conventional way. It has good flexibility, good focus and easy to realize the automation of multi-station equipment.
Brilliant Technology focuses on the development and research of laser micro-precision processing. Precision processing technology is applied in many industries such as aviation, aerospace, machinery, electronics, steel, metallurgy, medical and health. 应用解决方案。 We grasp the pulse of the development of society and the times in a timely manner, adhere to market-driven independent innovation, take laser processing applications in various industries as the breakthrough point, actively accumulate application experience, and combine the company's existing laser brazing system to launch unique laser welding applications solution. ，在市场上均获得广泛的好评。 At present, the company's main products include constant temperature laser soldering equipment, constant temperature high-speed laser soldering equipment and laser spray soldering equipment , which have been widely praised in the market.
型激光系统是一种紧凑型恒温激光锡焊系统，能提供连续功率大于30 W的980 nm红外激光输出。 The RZTS30B laser system is a compact thermostatic laser soldering system that can provide a continuous 980 nm infrared laser output greater than 30 W. This product has excellent performance. It is not only the best tool for material micro-welding and micro-marking, but also a high-efficiency pump source for high-power fiber lasers and solid-state lasers. The constant temperature laser soldering system is composed of an automatic robot, a temperature feedback system, a CCD coaxial alignment system and a semiconductor laser. It can import a variety of file formats to achieve the purpose of accurate welding. The coaxial alignment function can effectively ensure the constant temperature welding of welding points and the precise alignment of precision components, thereby ensuring an effective yield rate in mass production. This product is mainly suitable for PCB board spot welding, soldering, welding of metal and non-metal materials, sintering, heating, etc.
是一种激光喷锡焊接设备。 RZLJ08 is a laser spray soldering equipment. It can efficiently and flexibly handle a variety of precision electronic welding, and can easily and quickly perform MEMS, sensors, hard disk heads, camera module and other device conversions. RZLJ08 is equipped with a CCD positioning and monitoring system, a multi-axis intelligent conveying platform, and a universal clamping device, which can effectively guarantee welding accuracy and yield. Adopting solder ball spray drop welding, the welding accuracy is very high. For some welding areas that are very sensitive to temperature, the welding precision can be effectively guaranteed. The application range of solder ball is 50 um ~ 760 um. Laser spray soldering system This equipment can be used for welding of high precision components such as wafers, optoelectronic products, MEMS, product sensors, BGA, HDD (HGA, HSA), mobile phones, digital cameras, camera modules, etc., especially suitable for hard disk head Precision electronic welding.
型恒温高速激光锡焊系统是通过振镜的摆动电机高速偏转来改变激光光束的路径以实现焊接体的高速焊接，配套的同轴定位系统能自动的识别焊接体，专门为现代回流焊技术配合研发生产的一款激光选择性焊接，从而保证了自动化的高速生产，实现了高效率，高精度化的生产。 RZHS50A constant temperature high-speed laser soldering system uses high-speed deflection of the galvanometer's swing motor to change the path of the laser beam to achieve high-speed welding of the welding body. The matching coaxial positioning system can automatically identify the welding body. A laser selective welding with R & D and production ensures automatic high-speed production and achieves high-efficiency and high-precision production. Constant temperature laser galvanometer soldering system with selective soldering in modern reflow soldering process, suitable for solder paste applications, can be used in all SMT application areas, and compared to SMT, the heating method is local heating, when welding an original , Will not produce thermal effects on other components, but also applicable to the field of microelectronic connectors, such as ultra-thin coaxial wire and terminal welding, USB cable welding, flexible circuit board FPC or rigid circuit board PCB welding, high-precision LCD screen, TFT welding and high-frequency transmission lines.