SZFitech

 In the field of micro-optical display (Mini LED, Micro LED and COB package), the choice of solder paste needs to synthesize the three core dimensions of chip size, encapsulation process and reliability requirements, the specific program is as follows: 1. according to the chip size selection paste particle size: precision guarantee Mini LED (50-200μm) Recommended particle size: T6 type (5-15μm), No. 6 powder (5-15μm) or finer No. 7 powder (2-11μm). Reason: Mini LED chips are small in size and dense in pitch, so ultra-fine particle size solder paste is needed to realize precise printing and avoid bridging (short circuit) or lack of tin (false solder). For example, No. 7 powder (2-11μm) can meet the minimum of about 75μm × 150μm chip soldering needs to ensure that the solder joints are full and no risk of short circuit. Micro LED (≤50μm) Recommended particle size: T7 type (2-11μm), No. 8 powder (2-8μm) or finer No. 9 powder (1-5μm). Reason: Micro LED chips are extremely sma...

 The flip chip assembly process typically includes soldering, flux residue removal and underfill. As chips continue to miniaturize, the gap between the flip chip and the substrate decreases, making it increasingly difficult to remove flux residue. This inevitably leads to an increase in cleaning costs or affects the efficiency and reliability of underfill. Although no-clean processes using no-clean fluxes are commercially available, compatibility between residues left by no-clean fluxes and underfill chemistries remains a major issue. Poor compatibility typically results in impeded capillary bottom fill flow or bottom fill delamination. Epoxy flux is a new type of flux for flip chip packaging, its main components are resin (epoxy resin, acrylic resin, etc.), organic acid activator, thixotropic agent and solvent. In the reflow soldering process its organic components cured into a layer of epoxy resin glue, attached to the solder joints around, play a role in strengthen...

 The use of low-temperature solder paste in the electronics industry is gaining attention, especially with the miniaturization of integrated circuit components and the increase in the number of I/Os. While the traditional lead-free SAC solder reflow process is commonly used, high temperatures tend to lead to reliability problems, including low process yields and poor thermal cycling performance, which are often associated with warpage. Figure 1. Conventional SAC solder is prone to warpage due to high soldering temperatures. Low-temperature solder paste can be effective in solving warpage problems, and the industry typically uses SnBi alloys to improve process yields, eliminate the pillow effect and improve rework yields. However, in most applications, SnBi alloys are often not strong enough to replace lead-free (SAC) and eutectic tin-lead alloys. To enhance the strength, mechanical properties and reliability of SnBi solder joints, an effective method is to use epoxy...