SZFitech

  In microelectronics and semiconductor packaging, the most basic purpose of pad surface treatment is to ensure good solderability and conductivity of the pads. Since copper tends to exist as oxide in air and is unlikely to remain as pristine copper for long, other treatments are required for copper. Although in the subsequent assembly, strong flux can be used to remove most of the copper oxide, but the strong flux itself is not easy to remove, so the industry generally does not use strong flux. Common PCB surface treatment processes are OSP, HASL, IAg, ISn, chemical nickel gold, chemical nickel palladium gold, chemical thin nickel palladium gold, electroplated nickel gold and electroplated gold, the following will be introduced one by one. OSP OSP is a layer of organic solder film over the copper foil of the PCB pad, which melts/cracks away when soldering, and the solder reacts with the copper foil of the pad to produce the scallop-shaped Cu6Sn5 and nano-thick Cu...

  Silicon is a common crystal material with a low coefficient of thermal expansion in modern microelectronics. It is widely used in advanced packaging fields such as power devices and 3D packaging. However, as the packaging density increases, the heat generation of packaged devices increases significantly, which declines the reliability of silicon. Therefore, some industry insiders have attempted to solder Si substrates with high thermal conductivity copper to improve heat dissipation performance. However, ordinary alloy solder is difficult to wet on the silicon surface, which requires a new welding approach. 1. Ultrasonc-assisted Soldering Ultrasonic soldering can cavitate in liquid solder. Bubbles nucleate and grow in molten solder and finally collapse near the solid-liquid interface. High temperature and pressure generated by ultrasonic can destroy oxides and promote wetting between solder and base material. Hence, flux is not required for this scenario. In ord...

  Lead-containing solder paste, with its low cost, excellent soldering performance, and adaptability, finds extensive application across various sectors including electronics manufacturing, metal processing, LED lighting, the automotive industry, communication equipment, aerospace, and defense industries. Specific applications include: Electronic Manufacturing and Repair Field PCB Soldering: Leaded solder paste serves as the core material for PCB soldering in electronic manufacturing. By melting, it bonds electronic components to the circuit board, ensuring stable current conduction. Its strong wettability forms full, bright solder joints with minimal residue. Featuring high insulation resistance, it meets no-clean requirements, preventing PCB corrosion and delivering high joint reliability. Surface Mount Technology (SMT): In SMT processes, leaded solder paste connects small components like surface-mount resistors and capacitors, enabling precision printing on ...

  Solder paste is commonly used in the semiconductor packaging to connect chips and pads. Through printing, dispensing, and other processes, solder paste can become the connection medium between copper pads and chips. The solder paste melts during reflow soldering and solidifies into solder joints with uniform size, which achieves electrical interconnection. So what are the mechanisms of solder paste soldering? To understand it, you should have a basic understanding of wettability. Wettability is one of the key factors determining the soldering effect. Excellent wettability can be understood as the fact that the solder paste can diffuse along the surface of the pads and metallurgically connect with the copper pads to generate specific intermetallic compounds. The way to judge wettability is to look at the angle formed between the solder paste and the copper pads. Generally, an contact angle greater than 90° is defined as poor wettability, which means the surface ten...