What is wafer slicing technology
As a key link in semiconductor manufacturing process, wafer cutting and slicing technology is directly related to chip performance, yield and production cost.
#01 Background and significance of wafer cutting
1.1 Definition of wafer cutting
Wafer cutting (or slicing) is an important part of the semiconductor manufacturing process, the purpose of which is to divide the wafer through multiple processes into multiple independent grains. These grains often contain complete circuit functions and are the core components that are ultimately used to manufacture electronic products. With the reduction of chip design complexity and size, the accuracy and efficiency of wafer cutting technology are increasingly required.
In practice, wafer cutting usually uses high-precision cutting tools such as diamond blades to ensure that each grain remains intact and functional. The preparation before cutting, the precise control in the cutting process and the quality inspection after cutting are the key links. Before cutting, the wafer needs to be marked and positioned to ensure that the cutting path is accurate; In the process of cutting, it is necessary to strictly control the parameters such as the pressure and speed of the tool to prevent damage to the wafer. After cutting, a comprehensive quality inspection is also required to ensure that each chip meets the performance standards.
The basic principle of wafer cutting technology not only includes the selection of cutting equipment and the setting of process parameters, but also involves the mechanical properties of materials and the influence of material characteristics on the cutting quality. For example, low-K dielectric silicon wafers are easily affected by stress concentration during cutting due to their poor mechanical properties, resulting in failure problems such as cracking and cracking. The low hardness and brittleness of low-K materials make them more prone to structural failure when subjected to mechanical forces or thermal stress, especially during cutting, where tool contact with the wafer surface and high temperatures further exacerbate stress concentration.
With the progress of materials science, wafer cutting technology is not only applied to traditional silicon-based semiconductors, but also extended to new semiconductor materials such as gallium nitride. These new materials, due to their hardness and structural properties, bring new challenges to the cutting process and require further improvements in cutting tools and technologies.
Wafer cutting, as a key process in the semiconductor industry, is still being optimized as demand changes and technology advances, laying the foundation for future microelectronics and integrated circuit technology.
In addition to the development of auxiliary materials and tools, the improvement of wafer cutting technology also covers many aspects such as process optimization, equipment performance improvement and precise control of cutting parameters. These improvements are designed to ensure high precision, high efficiency and stability in the wafer cutting process to meet the semiconductor industry's demand for smaller, more integrated and more complex chips.
1.2 Importance of wafer cutting
Wafer cutting plays a key role in the semiconductor manufacturing process, directly affecting subsequent processes as well as the quality and performance of the final product. The following details the importance of wafer cutting from several aspects.
First, cutting accuracy and consistency are key to ensuring chip yield and reliability. In the manufacturing process, the wafer goes through multiple processes to form a number of tiny circuit structures, which need to be precisely divided into independent chips (grains). If the positioning or cutting error in the cutting process is large, it may cause circuit damage, and then affect the function and reliability of the chip. Therefore, high-precision cutting technology can not only ensure the integrity of each chip, but also avoid damage to the internal circuit of the chip and improve the yield.
Second, wafer cutting has a significant impact on production efficiency and cost control. Wafer cutting is an important step in the manufacturing process, and its efficiency directly affects the progress of subsequent processes. By optimizing the cutting process, increasing the degree of automation and cutting speed of the equipment, the overall production efficiency can be significantly improved. On the other hand, the material loss during cutting is also an important part of the cost control of enterprises. The use of advanced cutting technology can not only reduce unnecessary material waste in the cutting process, but also improve the utilization rate of wafers, thereby reducing production costs.
With the advancement of semiconductor technology, the diameter of wafer is increasing, and the circuit density is also increasing, which puts higher requirements on cutting technology. Large wafers require more precise cutting path control, especially in the high-density circuit area, where any small deviation can cause multiple chips to fail. In addition, larger wafers mean more cutting lines and more complex process steps, and cutting technology must further improve its accuracy, consistency, and efficiency to meet these challenges.
1.3 Wafer cutting process
The process flow of wafer cutting covers from the preparation stage to the final quality check, and each step is crucial to ensure the quality and performance of the chip after cutting. The following is a detailed explanation of the various stages.
The wafer cutting process involves cleaning, positioning, cutting, cleaning, inspecting and sorting wafers, and each step is critical. With the advancement of automation, laser cutting, and AI inspection technology, modern wafer cutting systems can achieve higher accuracy, speed, and lower losses. In the future, new cutting technologies such as laser and plasma will gradually replace traditional blade cutting to adapt to more complex chip design needs and further promote the development of semiconductor manufacturing processes.
#02 Wafer cutting technology and its principle
Three common wafer cutting techniques are shown in the figure, namely Blade Dicing, Laser Dicing and Plasma Dicing. The following is a detailed analysis of these three technologies and a supplementary explanation:
Wafer cutting is a key step in the semiconductor manufacturing process, which requires the selection of the appropriate cutting method according to the thickness of the wafer. First, you need to determine the thickness of the wafer. If the thickness of the wafer is more than 100 microns, the blade cutting method can be selected for cutting. If blade cutting is not applicable, you can turn to the fracture cutting method, which includes both scratch cutting and blade cutting.
When the wafer thickness is between 30 and 100 microns, the DBG (Dice Before Grinding) method is recommended. In this case, you can choose to scratch cut, blade cut, or change the cutting order as needed to achieve the best results.
For ultra-thin wafers with a thickness of less than 30 microns, laser cutting becomes the preferred method because it enables precise cutting of thin wafers without causing excessive damage. If laser cutting cannot meet specific requirements, plasma cutting methods can be used as an alternative. This flowchart provides a clear decision path to ensure that the most appropriate wafer cutting technology is selected for different thickness conditions.
2.1 Mechanical cutting technology
Mechanical cutting technology is the traditional method in wafer cutting, its core principle is to use high-speed rotating diamond grinding wheel cutting tool to cut wafer. Key equipment includes aerostatic spindles that drive diamond wheel tools at high speeds for precise cutting or slotting operations along a preset cutting path. This technology is widely used in the industry because of its low cost, high efficiency and wide applicability.
Advantage
The high hardness and wear resistance of diamond grinding wheel tools enable mechanical cutting technology to adapt to the cutting needs of a variety of wafer materials, whether traditional silicon-based materials or new compound semiconductors. Its simple operation and relatively low technical requirements have further promoted its popularity in mass production. In addition, compared with other cutting methods, such as laser cutting, the cost is more controllable, which is suitable for the needs of enterprises in mass production.
Limitation
Although mechanical cutting technology has many advantages, its limitations can not be ignored. First of all, due to the physical contact between the tool and the wafer, its cutting accuracy is relatively limited, and it is easy to produce size deviation, which affects the accuracy of subsequent packaging and testing of the chip. Secondly, the mechanical cutting process is easy to produce cracks, cracks and other defects, which not only affect the yield, but also may have a negative impact on the reliability and service life of the chip. This mechanical stress-induced damage is particularly bad for high-density chip manufacturing, especially when cutting brittle materials.
Technical improvement
To overcome these limitations, researchers continue to optimize the mechanical cutting process. It is an important improvement measure to improve the cutting precision and durability by improving the design and material selection of the grinding wheel tool. In addition, the structural design and control system of the cutting equipment are optimized to further improve the stability and automation level of the cutting process. These improvements reduce the error caused by human operation and improve the consistency of cutting. The introduction of advanced detection and quality control technology, real-time monitoring of abnormal conditions in the cutting process, but also effectively improve the reliability of cutting and yield.
Future development and new technologies
Although mechanical cutting technology still occupies an important position in the wafer cutting field, with the advancement of semiconductor processes, new cutting technologies are also developing rapidly. For example, the application of thermal laser cutting technology provides a new way to solve the problems of precision and defects in mechanical cutting. This non-contact cutting method can reduce the impact of physical stress on the wafer, greatly reducing the incidence of edge breakage and cracks, especially for cutting brittle materials. In the future, the combination of mechanical cutting technology and emerging cutting technologies will provide a wider range of options and flexibility for semiconductor manufacturing, further improving the manufacturing efficiency and quality of chips.
To sum up, mechanical cutting technology, despite its shortcomings, still plays an important role in semiconductor manufacturing through continuous technological improvement and combination with new cutting technologies, and is expected to maintain its competitiveness in future processes.
2.2 Laser cutting technology
Laser cutting technology as a new method in wafer cutting, because of its high precision, no mechanical contact damage and fast cutting characteristics, gradually received wide attention in the semiconductor industry. The technology uses the high energy density and focusing ability of the laser beam to create tiny heat-affected zones on the surface of the wafer material. When the laser beam is applied to the wafer, the thermal stress generated will cause the material to break at a predetermined location, achieving the effect of precise cutting.
Advantages of laser cutting technology
1. High precision: The precise positioning ability of the laser beam can achieve the cutting accuracy of the micron or even the nano level, meeting the requirements of modern high-precision and high-density integrated circuit manufacturing.
2. No mechanical contact: laser cutting does not need to contact the wafer, avoiding the common problems such as edge breakage and cracks during mechanical cutting, and significantly improving the chip yield and reliability.
3. Fast cutting speed: The high speed of laser cutting helps to improve production efficiency, especially for large-scale and high-speed production scenarios.
Challenges faced
1. High equipment cost: the initial investment of laser cutting equipment is high, especially for small and medium-sized production enterprises, and the promotion and application are still facing economic pressure.
2. Complex process control: Laser cutting requires precise control of multiple parameters such as energy density, focus position and cutting speed, and the process is highly complex.
3. Heat affected zone problem: Although the non-contact characteristics of laser cutting reduce mechanical damage, the heat affected zone caused by thermal stress may adversely affect the performance of the wafer material, and further optimization of the process is required to reduce this impact.
Direction of technological improvement
To solve these problems, researchers are focusing on reducing equipment costs, improving cutting efficiency and optimizing process flow.
1. Efficient lasers and optical systems: Through the development of more efficient lasers and advanced optical systems, not only can reduce equipment costs, but also improve cutting accuracy and speed.
2. Optimization of process parameters: In-depth study of laser and wafer material interaction, improve the process to reduce heat affected zone, improve cutting quality.
3. Intelligent control system: Develop intelligent control technology to realize the automation and intelligence of the laser cutting process and improve the stability and consistency of the cutting process.
Laser cutting technology performs particularly well in ultra-thin wafers and high-precision cutting scenarios. With the increase of wafer size and circuit density, traditional mechanical cutting methods are difficult to meet the needs of modern semiconductor manufacturing for high precision and high efficiency, and laser cutting is gradually becoming the first choice in these fields because of its unique advantages.
Although laser cutting technology still faces challenges such as equipment cost and process complexity, its unique advantages in high precision and no contact damage make it an important development direction in the semiconductor manufacturing field. With the continuous progress of laser technology and intelligent control systems, laser cutting is expected to further improve the efficiency and quality of wafer cutting in the future, and promote the sustainable development of the semiconductor industry.
2.3 Plasma cutting technology
As a new wafer cutting method, plasma cutting technology has attracted much attention in recent years. The technology uses high energy ion beam to cut the wafer accurately, and achieves the ideal cutting effect by accurately controlling the energy, speed and cutting path of the ion beam.
Working principle and advantages
The process of plasma cutting wafer relies on the equipment to produce a high-temperature high-energy ion beam, which can heat the wafer material to a melting or gasification state in a very short time, so as to achieve rapid cutting. Compared with traditional mechanical or laser cutting, plasma cutting is faster and has a smaller heat-affected area on the wafer, effectively reducing cracks and damage that may occur during cutting.
In practical applications, plasma cutting technology is particularly good at dealing with complex shapes of wafers. Its high energy plasma beam is flexible and adjustable, which can easily handle irregular shapes of wafers and achieve high precision cutting. Therefore, the technology has shown broad application prospects in the field of microelectronics manufacturing, especially in the high-end chip manufacturing of customized and small-batch production.
Challenges and limitations
Although plasma cutting technology has many advantages, it also faces some challenges. First of all, the process is complex and relies on high-precision equipment and experienced operators to ensure the accuracy and stability of the cutting. In addition, the high temperature and high energy characteristics of isoion beam put forward higher requirements for environmental control and safety protection, increasing the difficulty and cost of application.
Future development direction
Wafer cutting quality is critical to subsequent chip packaging, testing, and the performance and reliability of the final product. The common problems in the cutting process include cracks, edge breakage and cutting deviation, which are influenced by many factors.
The improvement of cutting quality requires comprehensive consideration of many factors such as process parameters, equipment and material selection, process control and detection. Through continuous improvement of cutting technology and optimization of process methods, the precision and stability of wafer cutting can be further improved, and more reliable technical support can be provided for the semiconductor manufacturing industry.
#03 Processing and testing after wafer cutting
3.1 Cleaning and drying
The cleaning and drying process after wafer cutting is essential to ensure chip quality and the smooth progress of subsequent processes. In this process, it is not only necessary to thoroughly remove the silicon chips, coolant residues and other pollutants generated during cutting, but also to ensure that the chip is not damaged during the cleaning process, and to ensure that there is no water residue on the surface of the chip after drying to prevent corrosion or electrostatic discharge caused by water.
The cleaning and drying process after wafer cutting is a complex and delicate process that requires a combination of factors to ensure the final treatment effect. Through scientific methods and rigorous operations, we can ensure that each chip enters the subsequent packaging and testing process in the best state.
3.2 Detection and testing
The chip inspection and testing process after wafer cutting is a key step to ensure product quality and reliability. This process can not only screen out chips that meet the design specifications, but also find and deal with potential problems in a timely manner.
The chip inspection and testing process after wafer cutting covers many aspects such as appearance inspection, size measurement, electrical performance test, functional test, reliability test and compatibility test. These steps are interconnected and complementary, and together constitute a solid barrier to ensure product quality and reliability. Through rigorous inspection and testing processes, potential problems can be identified and dealt with in a timely manner, ensuring that the final product can meet the needs and expectations of customers.
3.3 Packaging and Storage
The wafer-cut chip is a key output in the semiconductor manufacturing process, and its packaging and storage can not be ignored. Proper packaging and storage measures can not only ensure the safety and stability of the chip during transportation and storage, but also provide a strong guarantee for subsequent production, testing and packaging.
The chip packaging and storage after wafer cutting are crucial. Through the selection of appropriate packaging materials and strict control of the storage environment, the safety and stability of the chip during transportation and storage can be ensured. At the same time, regular inspection and evaluation work provides a strong guarantee for the quality and reliability of the chip.
#04 Challenges during wafer scribing
4.1 Microcracks and damage problems
During wafer scribing, microcracks and damage problems are urgent problems to be solved in semiconductor manufacturing. Cutting stress is the main cause of this phenomenon, which causes small cracks and damage on the wafer surface, resulting in increased manufacturing costs and reduced product quality.
As a fragile material, the internal structure of wafers is prone to change when subjected to mechanical, thermal or chemical stress, resulting in micro-cracks. Although these cracks may not be noticeable initially, they can expand and cause more severe damage as the manufacturing process progresses. Especially in the subsequent packaging and testing process, due to temperature changes and further mechanical stress, these micro-cracks may evolve into obvious cracks and even lead to chip failure.
Wafer surface damage can also not be ignored. These injuries can result from improper use of cutting tools, incorrect setting of cutting parameters, or material defects in the wafer itself. Regardless of the cause, these damages can negatively affect the performance and stability of the chip. For example, damage can cause a change in the value of resistance or capacitance in the circuit, affecting the overall performance.
In order to solve these problems, on the one hand, the stress generation in the cutting process is reduced by optimizing the cutting tools and parameters. For example, using a sharper blade and adjusting the cutting speed and depth can reduce the concentration and transfer of stress to a certain extent. On the other hand, researchers are also exploring new cutting technologies, such as laser cutting and plasma cutting, in order to further reduce the damage to the wafer while ensuring the cutting accuracy.
In general, microcracks and damage problems are key challenges to be solved in wafer cutting technology. Only through continuous research and practice, combined with various means such as technological innovation and quality testing, can the quality and market competitiveness of semiconductor products be effectively improved.
4.2 Heat affected areas and their impact on performance
In thermal cutting processes such as laser cutting and plasma cutting, heat affected areas are inevitably generated on the wafer surface due to high temperatures. The size and extent of this area is affected by a number of factors, including cutting speed, power, and the thermal conductivity of the material. The presence of heat-affected regions has a significant impact on the properties of the wafer material, and thus on the performance of the final chip.
Effects of heat affected areas:
1. Crystal structure change: Under the action of high temperature, the atoms in the wafer material may rearrange, resulting in crystal structure distortion. This distortion reduces the mechanical strength and stability of the material, increasing the risk that the chip will fail during use.
2. Electrical performance changes: Under the action of high temperature, the carrier concentration and mobility in the semiconductor material may change, which affects the conductive performance and current transmission efficiency of the chip. These changes can cause chip performance to degrade or even fail to meet design requirements.
Measures to control heat-affected areas:
1. Optimize cutting process parameters: By reducing cutting speed and reducing power, the generation of heat-affected areas can be effectively reduced.
2. The use of advanced cooling technology: liquid nitrogen cooling, microfluidic cooling and other technologies can effectively limit the range of heat-affected areas and reduce the impact on wafer material performance.
3. Material selection: Researchers are exploring new materials, such as carbon nanotubes and graphene, which have excellent heat conduction properties and mechanical strength, and can improve chip performance while reducing heat-affected areas.
In general, heat affected zone is an unavoidable problem in thermal cutting technology, but its influence on wafer material properties can be effectively controlled through reasonable process optimization and material selection. Future research will pay more attention to the refinement and intelligent development of thermal cutting technology to achieve more efficient and accurate wafer cutting.
4.3 Trade-offs between wafer yield and production efficiency
The trade-off between wafer yield and production efficiency is a complex and critical issue in wafer cutting and slicing. These two factors directly affect the economic benefits of semiconductor manufacturers, and are related to the development speed and competitiveness of the entire semiconductor industry.
The improvement of production efficiency is one of the goals pursued by semiconductor manufacturers. As market competition intensifies and the replacement rate of semiconductor products accelerates, manufacturers need to produce a large number of chips quickly and efficiently to meet market demand. Therefore, increasing production efficiency means that wafer processing and chip separation can be completed faster, which reduces production cycles, reduces costs, and increases market share.
Yield challenges: However, the pursuit of high production efficiency often has a negative impact on wafer yield. During wafer cutting, cutting equipment accuracy, operator skills, raw material quality and other factors can lead to wafer defects, damage, or dimensional discrepancies, thereby reducing yield. If the yield is excessively sacrificed in order to improve the production efficiency, it may lead to the production of a large number of unqualified products, causing a waste of resources and damaging the reputation and market position of the manufacturer.
Balance strategy: To find the best balance between wafer yield and production efficiency has become a problem that wafer cutting technology needs to constantly explore and optimize. This requires manufacturers to consider market demand, production cost and product quality and other factors to develop reasonable production strategy and process parameters. At the same time, the introduction of advanced cutting equipment, improve operator skills and strengthen raw material quality control to ensure that production efficiency while maintaining or improving yield.
Future challenges and opportunities: With the development of semiconductor technology, wafer cutting technology is also facing new challenges and opportunities. The continuous reduction of chip size and the improvement of integration put forward higher requirements for cutting accuracy and quality. At the same time, the emergence of emerging technologies provides new ideas for the development of wafer cutting technology. Therefore, manufacturers need to pay close attention to market dynamics and technological development trends, and continue to adjust and optimize production strategies and process parameters to adapt to market changes and technical requirements.
In short, by taking into account market demand, production costs and product quality, and introducing advanced equipment and technology, improving operator skills and strengthening raw material control, manufacturers can achieve the best balance between wafer yield and production efficiency in the wafer cutting process, resulting in efficient and high-quality semiconductor product production.
4.4 Future Outlook
With the rapid development of science and technology, semiconductor technology is advancing at an unprecedented speed, and wafer cutting technology, as a key link, will usher in a new chapter of development. Looking ahead, wafer cutting technology is expected to achieve significant improvements in precision, efficiency and cost, injecting new vitality into the continued development of the semiconductor industry.
Improve accuracy
In the pursuit of higher precision, wafer cutting technology will continue to push the limits of existing processes. Through in-depth study of the physical and chemical mechanisms in the cutting process, as well as precise control of cutting parameters, more fine cutting effects will be achieved in the future to meet the increasingly complex circuit design needs. In addition, the exploration of new materials and cutting methods will also significantly improve the yield and quality.
Increase efficiency
The new wafer cutting equipment will pay more attention to intelligent and automated design. The introduction of advanced control systems and algorithms enables the equipment to automatically adjust cutting parameters to different material and design requirements, resulting in a significant increase in production efficiency. At the same time, innovative means such as multi-slice simultaneous cutting technology and rapid blade replacement technology will become the key to improving efficiency.
Reduce cost
Cost reduction is an important direction of wafer cutting technology development. With the development of new materials and cutting methods, equipment costs and maintenance costs are expected to be effectively controlled. In addition, by optimizing the production process and reducing the scrap rate, waste in the production process can be further reduced, thus achieving an overall cost reduction.
Smart Manufacturing and Internet of Things
The integration of intelligent manufacturing and Internet of Things technology will bring new changes to wafer cutting technology. Through interconnection and data sharing between equipment, every step of the production process can be monitored and optimized in real time. This not only improves production efficiency and product quality, but also provides more accurate market forecasting and decision support for enterprises.
In the future, wafer cutting technology will make significant progress in multiple aspects such as accuracy, efficiency and cost. These advances will promote the continued development of the semiconductor industry and bring more scientific and technological innovation and convenience to human society.
Reference:
ZMKJ has advanced production equipment and technical team, which can customize SiC wafers, sapphire wafers, SOI wafers, silicon substrates and other specifications, thicknesses and shapes according to customers' specific requirements.
Singulation, the Moment When a Wafer is Separated into Multiple Semiconductor Chips - SK hynix Newsroom
Detecting Chipping Defects in Wafer Dicing | SOLOMON 3D (solomon-3d.com)
Panasonic and Tokyo Seimitsu Start Taking Orders for Their Jointly Developed Laser Patterning Machine for Plasma Dicing|NEWS | ACCRETECH - TOKYO SEIMITSU
Plasma Dicing Process | Others | Solutions | DISCO Corporation
Dicing by Laser (Laser Dicing) | DISCO Technology Advancing the Cutting Edge (discousa.com)
Basic Processes Using Blade Dicing Saws | Blade Dicing | Solutions | DISCO Corporation
Plasma Dicing 101: The Basics | Innovation | KLA
1 new message (yieldwerx.com)
Semiconductor Wafer Cleaning - Precision Grinding の ティ · ディ · シー TDC Corporation (mirror-polish.com)