According to a report by Maims Consulting, people’s demand for tablets, mobile phones, watches and other wearable devices tends to have complex functions but compact structures. Therefore, the shrinking size of semiconductor chips and packaged devices is of great importance to the development of microelectronics technology. The importance of Moore’s Law. The trend of advanced packaging technology has created a lot of opportunities for the development of lasers because of their extraordinary ability to perform high-precision processing tasks for various materials in the minimum heat affected zone (HAZ). Therefore, lasers are used in wafer cutting, package cutting (singulation), optical peeling, μ-via drilling, redistribution layer (RDL) structuring, dicing tape cutting (EMI shielding), welding, annealing and bonding, etc. It's getting more and more widely, here are just a few examples. This article elaborates on three distinct laser-based processes for a variety of dynamic applications. Nanosecond and picosecond lasers are used for system-in-package (SiP) cutting SiP technology can help high-end wearable devices or portable devices achieve miniaturization and high concentration of functions. SiP devices are composed of various circuit components, such as processors, memories, communication chips, and sensors, which are assembled on a PCB substrate with embedded copper wires. The assembly of all devices is usually encapsulated in a molded composite material, and an external conductive coating with electromagnetic shielding function is added. The thickness of the SiP device is about 1mm, of which the thickness of the molded composite material accounts for about half. In the manufacturing process, multiple SiP devices are first fabricated on a large panel, and finally divided into individual devices. In addition, in some cases, in the device, the trench will penetrate directly into the molded composite material until it is connected to the copper ground plane. This process is completed before the conductive shielding layer covers the device, and the conductive shielding layer is mainly used to completely cover the SiP area to isolate it from other high-frequency components. For cutting and grooving, the position and depth of the incision must be accurate, without charring, let alone debris. In addition, problems such as thermal damage, delamination or micro-cracks during the cutting process will cause irreversible consequences to the circuit. At present, 20-40W ultraviolet solid-state lasers with nanosecond pulse width (such as Coherent AVIA) are the main tools for SiP cutting. However, for nanosecond sources, there is a need to balance output power and cutting quality (especially edge quality and chip formation). Therefore, the processing speed cannot be easily increased simply by applying more laser power. Therefore, if the cutting quality is extremely high, you can choose a 532 nm (green) ultra-short pulse (USP) laser instead, such as Coherent HyperRapid NX picosecond laser or Monaco femtosecond laser. Compared with nanosecond lasers, they have a smaller cut, which can reduce the amount of HAZ and debris, and in some cases can even increase production. However, the only disadvantage of USP sources is their high input cost.　　 Excimer laser for RDL RDL is the key technology to realize almost all advanced packaging in the field of microelectronics, including flip-chip, wafer-level chip packaging, fan-out wafer-level packaging, embedded IC and 2.5D/3D packaging. RDL is to route circuits through patterned metal and dielectric layers, allowing each silicon-based chip to be connected to other chips. In this way, RDL can re-plan the die's input/output route. Currently, most RDLs are constructed with "lithographically defined" dielectrics, in which the required circuit patterns are first printed by photolithography, and then wet etching is used to remove exposed or unexposed areas. However, lithographically defined polymers have several disadvantages, such as high cost, complex processing, and the coefficient of thermal expansion (CTE) does not match the bonding material. In addition, there is a risk of failure of good die due to circuit failure caused by photoresist residue. Nowadays, a new solution is born, which can directly ablate patterning by using a 308nm excimer laser by using suitable non-optical dielectric materials. The cost of these non-optical media is much lower than the materials defined by photolithography, and the stress generated by them is smaller, the CTE matching is better, and the mechanical and electrical properties are better. Here, the laser is projected through a lithography plate containing the desired pattern, then the substrate is burnt (larger than the projected pattern), moved, and then ablated until all areas are patterned. Excimer laser ablation is an economical high-throughput patterning method because it has fewer steps than the dielectric patterning method defined by photolithography, and does not require the use of wet chemicals. It can be called a "green" process. The RDL structure tool based on excimer laser has been put into use based on the Coherent LAMBDA SX series laser. The high pulse energy (> 1 J) and repetition rate (300 Hz) of these excimer lasers can provide fast throughput for feature sizes as low as 2μm. In addition, the advantages of excimer laser ablation are also manifested in the excellent control of feature depth and "sidewall angle". The latter is particularly important, because the "shadows" on both sides of the large-angle pattern will have a negative impact on the subsequent metal sputtering or vapor deposition process. CO2 and CO lasers are used for LTCC cutting and drilling Many packaging applications nowadays involve low-temperature co-fired ceramics (LTCC), which is becoming more and more popular as a microelectronic substrate for power or communication devices. LTCC is processed into green (unfired) ceramics, usually manufactured on a chlorinated polyethylene (PET) tape layer with a thickness in the range of 50μm to 250μm and a thickness of about 40μm to 60μm. In the manufacture of LTCC circuits, lasers are mainly used in two processes: dicing (cutting) and drilling through holes. Dating back to history, CO2 lasers have been used for LTCC cutting. First, a laser is used to create a row of closely spaced holes, which penetrate into the middle layer of the substrate (such as a dicing groove), and then mechanical force is used to break the material along the dicing groove. Nowadays, as a substitute for CO2 laser, CO laser has attracted more and more attention. The industrial CO laser introduced to the market by Coherent a few years ago is similar to the CO2 technology, except that the output wavelength of the CO laser is about 5μm. The absorption of this shorter wavelength in LTCC is significantly lower than the 10.6 m CO2 wavelength. This allows the laser to penetrate further into the substrate and the scribing depth is deeper, which makes the material easier to break (see Figure 3). Moreover, lower absorption also produces smaller HAZ. For a long time, LTCC drilling through holes has also relied on CO2 lasers. But for this technology, green wavelength USP lasers may become the preferred alternative to CO2. This is because the USP laser can perfectly balance the contradiction between quality and yield. Specifically, a 50W green USP laser can produce 30μm through holes in 0.60mm ceramic at a rate of over 2000 holes per second. However, on the other hand, CO lasers can also replace USP lasers. CO lasers have been proven to produce through holes larger than 40μm in 0.65mm thick fired ceramics at a rate higher than 1000 holes/sec. Therefore, depending on the thickness of the ceramic and the required diameter, both USP and CO lasers are the best choices for LTCC drilling through holes. Similar basic advantages In short, although a variety of laser technologies are currently used in semiconductor packaging, they all have similar basic advantages. Specifically, these non-contact processing, which involve the production of high-precision features, usually have little impact on surrounding materials and have high yields. In addition, laser processing is "green" because it does not require the use of hazardous or difficult-to-handle chemicals. Super High Voltage Film Capacitor Polyester Film Capacitor,DC Filter Capacitor,Precision Capacitor XIAN STATE IMPORT & EXPORT CORP. , https://www.shvcomponents.com