When cutting and removing silicon wafers maximum precision is required with the smallest contours on an extended surface. The classic mechanical method of wafer dicing reaches its limits here, as it cannot meet the requirements for fineness and precision. This is precisely where the use of ultrashort pulse (USP) laser technology with a spectral range of typically 1 µm scores points in the processing of silicon.
Advantages of USP laser processing for silicon wafers
The use of ultrashort pulse lasers in the spectral range of 1 µm enables extremely fine and precise processing of silicon wafers. This innovative technology produces highly complex structures with maximum precision, even on large surfaces, which is of crucial importance for applications in the semiconductor industry. By dispensing with the mechanical processing steps of wafer dicing and instead making targeted use of USP laser technology with a wavelength of 1 µm, the silicon wafer is no longer exposed to mechanical stress, thereby avoiding potential damage such as chipping and cracks in the material.
The advantage of USP laser technology lies in the extremely short pulses, which do not cause any thermal input and therefore no damage to the material. In addition, processing with the USP laser has a smaller kerf width, which results in less kerf loss and therefore a higher yield of chips per wafer compared to wafer dicing. This results in a more efficient use of the wafer material and contributes to cost savings. The process is also characterized by high speed, which leads to significantly shorter processing times and thus increases productivity. Two further decisive advantages over the previous mechanical process are the reduced need for post-processing steps, as there is no burr formation or melt adhesion, and the elimination of a liquid cooling medium, which reduces resource consumption and wafer contamination at the same time. In addition, laser processing enables free-form contours including 3D processing, which is particularly important for the creation of cavities, channels, inclined planes and blind holes.
In summary, USP laser processing not only offers a precise solution to the challenges of silicon wafer processing, but also optimizes the efficiency, sustainability and quality of the entire process.
EXCURSUS: Why are silicon wafers so indispensable today?
Silicon wafers are indispensable in many areas of technology today, mainly due to three characteristics of the material:
Firstly, silicon has unique properties such as its electrical conductivity, its crystalline and therefore regular lattice structure for the production of precise and reliable semiconductor components, its high material stability and reliability for long-term use in electronic systems, as well as optical properties for applications in photonics and the optoelectronic industry.
The availability in large quantities should also be mentioned. Silicon is available in almost unlimited quantities, as it is the second most common element in the earth's crust.
The third aspect is the widespread use of silicon. In the semiconductor industry, it serves as the basis for the production of semiconductor components such as microchips, transistors and diodes. These components are essential parts of electronic devices, from computers and smartphones to industrial controls and communication technology. They are also important in energy generation and storage. Here, silicon wafers are used in solar cells in photovoltaic modules to convert sunlight into electrical energy. They also play an important role in battery and energy storage systems for storing renewable energy. In electronics and sensor technology, silicon wafers are used in electronic devices such as sensors, actuators and microelectromechanical systems (MEMS) for applications in the automotive industry, aerospace, medical technology and many other areas. Silicon wafers also form the basis for the manufacture of microprocessors and other integrated circuits, which are essential for data processing and communication in computers, mobile devices, network devices and other electronic systems.
New growth market silicon photonics: silicon enables new solutions and applications
An important driver for the silicon photonics market is the constantly growing global data transfer. This is where heat generation in data centers is increasing, as electronic cables, circuits and chips require a lot of energy, much of which ends up as useless waste heat. The solution: thanks to microelectronic processes, individual components as well as complete photonic systems can be printed lithographically on silicon wafers, enabling the integration of laser and sensor systems or photonic integrated circuits (PICs) on chips. This in turn enables optical broadband communication, for example. Optical data transmission via fiber optic cables is far more efficient than previous electronic data transfer, as there is practically no thermal reaction even at the highest data traffic.
Another solution is the full integration of LiDAR systems on silicon chips, including so-called lidar system-on-chip concepts for autonomous vehicles. Also, worth mentioning are platforms based on photonic integrated circuits, or PICs for short, for biomedical sensor technology used in wearables.
In all of these examples, silicon enables promising new solutions and therefore also applications.
Versatile applications for USP laser technology
LCP has been successfully using USP laser technology for its customers for years for the micromachining of all materials and can draw on sound knowledge. In addition to the processing of silicon wafers, a wide range of other applications are possible:
- Cutting the thinnest foils without distortion with the smallest web widths and slots
- Insertion of predetermined breaking points in brittle-hard materials for subsequent separation
- Creation of microstructures in materials that are difficult to etch or cut
- Structuring/decoating of coated components
- Creation of defined surface structures for special molding, adhesion and friction properties
- Introduction of special surface geometries with shallow depths to improve friction properties
- Laser drilling of micro-holes, also in multiple arrangements
- Cutting of ceramic and metallic materials without thermal interaction
- Cutting of glass wafers from materials such as Borofloat® 33, D 263® T eco, AF 32®, AS87®, MEMpax®, BK7 and quartz glass
- Clean, stress-free processing of plastics/ PCB materials (FR3, FR4, FR5, polyimide, Kapton®/ Pyralux®) without carbonization of the cut edge
Header image: ©Anatoly Morozov by Getty Images/Canva
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