SZFitech

 Flip-chip interconnection technology has been widely used in high-performance and consumer electronics. High-performance packaging has achieved steady development, realizing the interconnection with more than 10,000 I/Os and a pitch of less than 200um, realizing the transition from ceramic substrates to low-cost organic substrates, and achieving the popularization of lead-free solder pastes. The transition to organic substrates has prompted low-temperature solder pastes to replace high-temperature solder pastes. As we all know, organic materials are usually epoxy resins, which are unstable at temperatures above 250°C for a long time. One way to avoid this problem is to deposit a low-temperature solder paste on the high melting point bump or the laminate pad. As shown in the figure below, the high melting point solder bumps are interconnected with the low-temperature solder pastes on the pads. This combination allows for the assembly of chips and laminate substrates ...

 With the advent of the post-Moore era, electronic components are gradually developing in the direction of miniaturization, complex structure, and functional integration. Laser soldering has become popular for improving soldering processes with its unique advantages of non-contact, selective local heating, and high precision. What we know is that laser soldering can solve the problems of difficulty in improving precision and the high cost of small batch production in traditional reflow soldering. Since intermetallic compounds play a vital role in the reliability of solder joints, researchers are eager to discover the impact of laser soldering on the evolution of intermetallic compounds in solder joints. Experimental design In order to understand the effect of laser soldering on IMC morphology, Zhao et al. (2023) used 0.64 mm diameter SAC305 solder wire to conduct laser soldering experiments. The Cu pad used in the test has a diameter of 3mm and a thickness of 35μm. Th...

 In the electronic assembly process, dropped parts and solder balls are common quality problems, they have a direct impact on the reliability and performance of the product. The following is a detailed analysis of the problem of dropped parts and solder balls: 1. Dropped parts Influencing factors: Solder adhesion: the adhesion between the solder and the component pin is a key factor in preventing dropped parts. The stronger the bond, the more stable the component is during the soldering process, and the lower the probability of dropping. Component type: different types of components due to their size, weight and shape differences, the welding stability requirements are different. For example, 0201 capacitors and resistors, compared to the capacitor drop probability is high. This is because the average height of the capacitor is 0.305mm, the quality of 0.00028g, while the average height of the resistor head 0.229 ~ 0.254mm, the quality of 0.00014g. In the placement pro...

 Flip chip (FC) technology is a packaging method in which the chip is directly attached to the substrate, which has the advantages of high density, high performance and low cost. However, due to the coefficient of thermal expansion (CTE) mismatch between the chip and the substrate, the solder joints are subjected to large thermal stresses when the temperature changes, leading to fatigue damage and failure. To improve the reliability of solder joints, a common method is to inject a polymer material, called underfill, between the chip and the substrate. Underfill improves the stress distribution in the solder joint, reduces the strain amplitude in the solder joint, and extends the thermal fatigue life of the solder joint. Figure 1. Underfill process Underfill is a liquid encapsulant, typically an epoxy resin heavily filled with SiO2, that is used between the chip and the substrate after flip chip interconnections. After curing, the hardened underfill has a high modulus...

 Fine-pitch components (e.g. QFN, BGA, etc.) have extremely high requirements for solder paste uniformity, thickness and edge definition due to their small pin spacing. Any minor printing defects can lead to poor soldering, such as bridging, open circuits or empty soldering. Therefore, these special requirements must be fully taken into account when setting acceptable conditions. Acceptable conditions for solder paste printing graphics are set as follows: Reject and Acceptable Conditions for Solder Paste Printed Graphics are shown in Tables 1-1 and 1-2 and are based on the fact that the widespread use of solder paste inspection technology has made the amount of solder paste measurable. Due to the different impact of the amount of solder paste on different packages, it is not possible to have a uniform standard, must be based on the use of the package, pad size, stencil openings, etc. Consideration, and here only provides a way of thinking for reference. Based on the ...

 The phenomena of less tin and missed prints in the SMT (Surface Mount Technology) process are common quality problems, and they have an important impact on the quality and reliability of products. The following is a detailed analysis of these two phenomena: tin deficiency There are many reasons for less tin, such as the thickness of the template, the shape of the hole and the sidewall roughness, the size of the tin powder particles, scraper pressure, solder paste rheology, and so on. The performance of tin deficiency is mainly a graphic defects, as shown in Figure1-1 Figure 1-1 tin deficiency phenomenon Main reason: 1. Template issues: The thickness of the stencil is one of the main reasons for the lack of tin. More accurately, it is the stencil opening area ratio is small, the process generally requires an area ratio of more than 0.66. Here we need to pay attention to two points, first, this data itself is a 70% transfer rate data; second, with the introduction of ...

 Furnace temperature profile design is a complex and critical process, which directly affects product quality and production efficiency. In the design of the temperature curve, the following aspects need to be noted: 1. the encapsulation body characteristics limitations Thermal capacity: the thermal capacity of the encapsulation body as well as the device carrier board fixtures determine the ability to absorb and store heat. For large heat capacity of the package body (such as copper substrate / thick fixture / large substrate chip, etc.), even if there is no limitations on the rate of warming, to reach a higher peak temperature will take longer. Heated area and thermal conductivity: the heated area affects the rate of heat absorption, while the thermal conductivity determines the rate of heat transfer inside the package. These two factors together determine the temperature response of the package in the heating process. 2. the process and equipment limitations Warm...