![]() It has excellent strength and high reliability. Gold-tin solder paste has a melting point of 280℃. Indeed, people have found an ideal eutectic alloy consisting of Au80Sn20. Regarding solving the temperature problem of lead-free solder in the secondary reflow, the traditional idea is to find alloys with melting points higher than the peak reflow temperatures of the existing SAC solder paste series alloys. However, this alloy is bismuth base, leading to poor heat transfer performance, which can be used only on some specific occasions to meet the requirements of secondary reflow. It is also a lead-free solder paste, which can meet the temperature requirements of the secondary reflow. BiAgX solder paste has a melting point of 262☌, which has exceeded the peak reflow temperature of the SAC solder paste series (255☌). Since SnSb10 and SnSb5 solder powders are not eutectic, and both have a certain melting range (solidus and liquidus do not overlap), the application of these solder powders is not widely recognized. Moreover, the melting points of SnSb10 and SnSb5 solder pastes are only less than 20☌ higher than that of commonly used SAC305 solder paste and SAC0307 solder paste. However, Antimony (Sb) is also restricted in the West because it is regarded as a heavy metal harmful to the human body. In the lead-free high-temperature range, the alloys available are SnSb10 solder paste (melting point: 242-255℃), SnSb5 solder paste (melting point: 245☌), and BiAgX solder paste (melting point: 262☌). Traditional l ead- f ree s older p aste s olution and i ts d isadvantages for t he s econdary r eflow s olderingĭue to the constraints of the metal phase, limited types of solder paste alloys can be selected by the solder industry. ![]() It has become a hot spot in the microelectronics and semiconductor packaging solder industry.Ģ. The application of high-lead solder paste product Pb92.5Sn5Ag2.5 will be gradually limited, which puts forward urgent requirements for high-temperature lead-free solder paste. With the miniaturization of artificial intelligence, the Internet of Things, and wearable electronic products, the international microelectronics and semiconductor packaging industry and even the military industry have higher requirements for lead-free products. This is the reason why high-lead solder pastes are still exempted in some areas when the global solder has been lead-free for 20 years. If the components are soldered on the circuit boards by secondary reflow, whether using SAC305 lead-free solder paste, Sn63Pb37 leaded solder paste, or Bi58Sn42 low-temperature lead-free solder paste, the peak reflow temperatures will not exceed the melting point of high-lead solder paste. The traditional solder for secondary reflow is high-lead solder paste, such as Pb92.5Sn5Ag2.5, with the first reflow soldering temperature of 290-310℃. However, they should have the same or similar soldering strength. The problem is that the solder pastes used for secondary reflow soldering cannot have the same soldering temperatures. In addition, after some components are soldered on one side of the circuit board, other components must be soldered on the other side, which should perform secondary soldering. For example, after the chip or component is packaged and soldered, the components need to be connected to the circuit boards by the second reflow soldering. ![]() Many components and circuit boards encounter problems during secondary reflow when using solder paste in the microelectronics and semiconductor packaging industry. S econdary r eflow p rocess puts forward requirements for l ead- f ree s older p aste Secondary reflow soldering, lead-free solder paste, high-strength low-temperature lead-free solder, reflow profile & solutionġ. Similarly, it is a perfect solution for circuit boards that require double-sided secondary reflow. The strength of the solder joint is similar to that of the SAC solder paste series alloy, which perfectly solves the problem of the lead-free solder paste alloy selection for the secondary reflow of components and circuit boards. ![]() FL series low-temperature high-strength solder paste is used at the second soldering of secondary reflow soldering. It is designed to use ordinary SAC305 solder paste or SAC0307 solder paste at the first soldering of secondary reflow soldering. Fitech proposed a new secondary reflow solution for microelectronics and semiconductor packaging based on the company's patent. ![]()
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