What are the application areas of laser packaging technology? (Laser bonding)

In recent years, with the development of 5G, non-silicon semiconductor materials such as electric vehicles, the Internet of Things, artificial intelligence, cloud computing, gallium arsenide, gallium nitride, and silicon carbide have attracted much attention. The research and development and application of new materials and downstream terminals have also gradually attracted attention. The increase in the number of chip production lines shows that the market space for the sealing and testing industry is very large. It has brought many opportunities to companies, but also faced many challenges. At present, the domestic sealing and testing industry chain has not yet been perfected, and it is highly dependent on foreign equipment and materials, and the level of localization of equipment and materials needs to be improved. From last year's ZTE incident to this year's Huawei incident, domestic companies have felt the importance of chip self-sufficiency and the necessity and urgency of the semiconductor industry chain.

Application of laser technology in advanced packaging

1. Laser bonding technology

Currently commonly used bonding technologies are: eutectic bonding technology and anodic bonding technology. Eutectic bonding technology has been used to manufacture various MEMS devices, such as pressure sensors, micro pumps, etc. , requiring the mechanical support structure to be bonded on the substrate. Silicon melt bonding is mainly used in SOI technology, such as Si-SiO2 bonding and Si-Si bonding, but this bonding method requires a higher annealing temperature. Anodic bonding does not require high temperature, but requires a strong electric field of 1000-2000V for effective bonding. This strong electric field will affect the performance of the wafer. Therefore, many researchers have introduced a bonding method called laser-assisted bonding, the principle of which is to focus the pulsed laser on the bonding interface and use the local thermal effect of the short-pulse laser to achieve local heating bonding. This bonding method has many advantages, such as no pressure, no high-temperature residual stress, and no strong electric field interference.

As the thickness of the wafer size gradually increases and becomes thinner, the wafer is easily fragmented during the flow process, so a carrier layer is introduced. The thin wafer is combined with the carrier layer to prevent the wafer from being damaged during the flow process. Compared with other disassembly bonds, laser disassembly bonds can use polyimide as a bond and agent. This method can withstand temperatures above 400掳C, while general bonding agents will denature at 200掳C, which makes general bonding agents fail during high and low temperature cycles. Since the laser disassembly and bonding technology requires the laser to act on the adhesive between the carrier and the wafer, the carrier needs to be able to pass the laser of the corresponding wavelength. At present, ultraviolet lasers are widely used, and the carrier is a glass wafer substrate. Laser disassembly and bonding technology is mainly used to peel off various thin silicon wafers.

2. Laser Grooving Technology

If the traditional knife wheel cutting solution is adopted, when cutting with the knife wheel, if the traditional knife wheel cutting solution is adopted, the edge collapse, curling, peeling and other undesirable phenomena are easy to occur in the low-k layer; the non-contact laser processing solution can effectively avoid the above problems.

The light spot is focused on the material surface through the optical path system to form a specific shape and achieve a specific groove type; the advanced laser cold processing technology uses the peak power of the ultrafast laser to directly convert the material from solid to gas, greatly reducing the heat affected zone.

3. Good laser cutting technology

The laser modification cutting process is suitable for materials such as silicon, silicon carbide, sapphire, glass, and gallium arsenide. By focusing the laser beam inside the bottom layer of the wafer liner, the internal modified layer of the cut is formed by scanning, and then the adjacent particles are destroyed by the cutting knife or vacuum crack. Laser improvement in the cutting process

The laser cutting width of laser cutting is almost zero, which helps to reduce the width of the cutting road surface; the deterioration of the material inside can inhibit the production of cutting pieces, and no coating cleaning is required. During the cutting process, DRA autofocus is used to automatically adjust the focus in real time to ensure that the depth of the modified layer of laser focus modification cutting is consistent.

4.TGV technology

TGV technology is a process of vertically extracting electrical signals from a sealed cavity by manufacturing vertical electrodes between chips. This technology is widely used in the fields of air tightness, electrical performance, packaging compatibility, consistency, reliability, etc. It is an effective way to miniaturize and highly integrate MEMS devices.