Application solutions for wafer fab management and product management design based on RFID technology

1. Background Introduction

Amid the rapid development of the semiconductor industry, wafer fabs, as a core manufacturing link, face unprecedented management challenges. Realizing refined, efficient and intelligent management has become a top priority for ensuring product quality, improving production efficiency and optimizing cost structure.

2. Analysis of the pain points of wafer fab management and product management

(I) Parameter drift and monitoring dilemma in complex processes

Wafer manufacturing involves highly precise and complex processes such as lithography, etching, and ion implantation. In the lithography process, slight fluctuations in the wavelength of the light source and instability in the exposure dose may lead to pattern accuracy deviations; during etching, slight changes in the etching rate may affect the consistency of the line width; during ion implantation, deviations in the injection energy and dose will directly affect the performance of semiconductor devices. However, the current monitoring system has problems of insufficient real-time performance and limited accuracy, which makes it difficult to detect and correct the drift of process parameters in a timely manner, and the product yield fluctuates greatly, with an average yield of only 85%, while the industry-leading level can reach 95%.

(II) Raw material quality fluctuations and traceability problems under multi-level supply chains

The raw materials required for wafer production, such as silicon wafers, photoresists, and specialty gases, come from suppliers around the world. The multi-level structure and complex logistics of the supply chain make raw materials susceptible to environmental factors during transportation and storage, resulting in quality fluctuations. Once a product has quality problems, it becomes extremely difficult to trace the source and batch of raw materials. The current traceability system often relies on manual records and paper documents, and the integrity and accuracy of information are difficult to guarantee. The traceability success rate is less than 60%, which seriously affects the root cause analysis and resolution of the problem.

(III) Equipment compatibility and maintenance challenges in the advancement of advanced processes

As semiconductor process technology continues to move towards smaller nodes, wafer fabs have introduced a large number of advanced manufacturing equipment. These devices come from different suppliers and have different control systems and interface standards, which leads to prominent compatibility issues between devices. The high frequency of equipment operation and complex process conditions also lead to frequent equipment failures. Traditional preventive maintenance methods are often based on fixed time intervals and cannot accurately predict the actual failure points of the equipment, resulting in increased unplanned downtime and reduced production efficiency. The average unplanned downtime per month exceeds 20 hours, with direct economic losses of up to millions of dollars.

(IV) Ultra-clean environment requirements and particulate pollution control problems

Wafer manufacturing must be carried out in an ultra-clean environment, with extremely strict requirements on particulates, chemical pollutants and static electricity in the air. However, during the operation of the current purification system, particulate pollution is difficult to completely avoid due to the aging of the filter, uneven distribution of airflow, and the entry and exit of personnel and materials. The monitoring methods for particles are relatively backward, and it is impossible to achieve real-time, multi-point accurate monitoring, which increases the risk of product contamination and affects the reliability and performance of the product.

(V) Integration of intelligent management systems and data security risks

In order to improve management efficiency, wafer factories have introduced multiple independent management systems, such as manufacturing execution systems (MES), enterprise resource planning (ERP), quality management systems (QMS), etc. However, the integration between these systems is low, data flow is not smooth, and information islands are formed. At the same time, with the improvement of the degree of digitalization, the generation and transmission of a large amount of production data has brought serious data security risks, such as data leakage, tampering and loss. Once it occurs, it will have a huge impact on the core competitiveness of the enterprise.

III. RFID solution

(I) RFID tag Selection and Deployment

Carefully select high-performance RFID tags that adapt to extreme process conditions to ensure stable operation in high temperature, high corrosion and strong electromagnetic field environments. Accurately install tags on wafers, key raw materials, equipment and fixtures to achieve seamless coverage of the entire process.

(II) System Architecture Design

Build a multi-level distributed system architecture based on the Internet of Things (IoT), integrating edge computing and cloud computing technologies to achieve rapid data collection, local preprocessing and remote centralized analysis.

(III) Real-time monitoring and automatic adjustment of process parameters

Through the RFID sensors deployed on the equipment and production lines, the process parameters are collected in real time, and the parameters are automatically adjusted and optimized with the help of advanced data analysis algorithms and machine learning models, so as to increase the product yield to more than 92%.

(IV) Traceability of the entire life cycle of raw materials

Each batch of raw materials is given a unique RFID tag, and its circulation trajectory and quality information are recorded throughout the process from procurement, warehousing, material collection, use to finished product shipment, ensuring that the accuracy and timeliness of raw material traceability reaches more than 98%.

(V) Predictive maintenance and intelligent scheduling of equipment

Using the equipment operation data collected by RFID, combined with the historical failure data and operating conditions of the equipment, a predictive maintenance model is established to predict potential equipment failures in advance, optimize equipment scheduling, and reduce unplanned downtime by more than 50%.

(VI) Real-time monitoring and intelligent control of ultra-clean environment

Deploy high-density RFID particle sensors to achieve real-time and multi-point monitoring of particle distribution in the clean room, combined with intelligent ventilation and filtration systems, dynamically adjust environmental parameters, and control particle pollution within international standards.

(VII) Deep integration of intelligent management systems and data security assurance

Use unified data standards and interface specifications to achieve deep integration of RFID systems and other management systems to break information silos. At the same time, advanced data encryption, Access Control and backup recovery technologies are introduced to ensure the security, integrity and availability of data.

IV. Specific application and implementation details of RFID technology in wafer fab management

(I) High-precision monitoring of lithography process

Install high-resolution RFID sensors on lithography equipment to collect key parameters such as light source wavelength and exposure dose in real time, and achieve sub-nanometer precision monitoring of lithography process through real-time comparison with preset standard values. Once the parameters deviate from the set range, the system automatically triggers an alarm and makes corresponding adjustments to ensure that the pattern accuracy deviation is controlled within ±10nm.

(II) Dynamic monitoring and feedback control of etching rate

Deploy micro RFID sensors in the reaction chamber of the etching equipment to monitor the parameters such as flow rate, pressure and temperature of the etching gas in real time, and dynamically calculate the etching rate in combination with the chemical analysis model. According to the changes in etching rate, adjust process parameters such as RF power and bias voltage in real time to control the consistency of etching line width within ±5%.

(III) Precise dose control of ion implantation process

High-precision RFID sensors are installed on the ion source and acceleration electrode of the ion implantation equipment to measure the energy and dose of the injected ions in real time. Through real-time comparison with the preset target value, a closed-loop feedback control system is used to accurately adjust the acceleration voltage and magnetic field strength to ensure that the deviation of the ion implantation dose is controlled within ±2%.

(IV) Real-time tracking of raw materials in multi-level supply chains

RFID tags with unique identification codes are attached to each batch of raw material packaging. During the warehousing, storage, collection and use of raw materials, handheld or fixed RFID Readers are used to collect the location and status information of raw materials in real time. At the same time, real-time docking with the supplier's database is carried out to obtain detailed information on the raw materials at the supply end, so as to achieve real-time tracking of the entire chain of raw materials from source to use.

(V) Preventive maintenance and spare parts management of advanced equipment

RFID sensors installed on key components of the equipment are used to monitor parameters such as equipment operation time, vibration amplitude, temperature change, etc. in real time. Based on these data, a health model of the equipment is established to predict potential failure points and maintenance needs. According to the prediction results, spare parts are prepared in advance, and maintenance plans are arranged reasonably to increase the spare parts inventory turnover rate of the equipment by more than 30%, while reducing the out-of-stock rate of spare parts to less than 5%.

(VI) Intelligent zoning control and particle traceability of ultra-clean environment

Multiple areas are divided in the clean room, and multiple RFID particle sensors are deployed in each area to monitor the number and particle size distribution of particles in real time. According to the monitoring data, the wind speed and wind direction of the ventilation system are intelligently adjusted to achieve independent control of different areas. When the particles exceed the standard, the source of the particles can be quickly traced, and targeted measures can be taken to eliminate them to ensure the stability and reliability of the ultra-clean environment.

(VII) Management system integration and data visualization analysis

Through middleware and data interfaces, the RFID system is deeply integrated with management systems such as MES, ERP, and QMS to achieve seamless data circulation and sharing. Using big data analysis and visualization technology, the collected data is presented to management personnel in the form of intuitive charts, providing real-time and accurate basis for decision-making.

V. Cost-benefit analysis

(I) Cost input

1. RFID tag cost: 0.5 yuan/piece, 200,000 tags are expected to be needed, totaling 100,000 yuan.

2. Read-write device cost: 3,000 yuan/unit, 80 devices are required, totaling 240,000 yuan.

3. System development and integration cost: 80,000 yuan.

4. Training and maintenance cost: 20,000 yuan/year.

(II) Benefit improvement

1. Benefits brought by improved product yield: the yield rate increased from 85% to 92%, and the annual profit is expected to increase by 8,000,000 yuan.

2. Reduced losses due to improved raw material traceability efficiency: the accuracy and timeliness of traceability are improved, and the losses caused by quality problems are reduced by 5,000,000 yuan each year.

3. Reduced downtime losses due to equipment maintenance optimization: Unplanned downtime is reduced by 50%, saving 3,000,000 yuan in production losses each year.

4. Product quality improvement benefits brought by improved ultra-clean environment control: Improved product reliability, increasing market share by 4,000,000 yuan each year.

5. Efficiency improvement benefits brought by management system integration: Improved decision-making accuracy, saving 2,000,000 yuan in management costs each year.

(III) Return on investment analysis

It is expected that the investment cost will be recovered within half a year.

VI. Challenges and coping strategies that RFID solutions may face

(I) Radio frequency signal interference and shielding issues

There are many high-frequency devices and complex electromagnetic field environments in the wafer factory, which may interfere with RFID signals. Use anti-interference radio frequency bands, optimize the antenna design of the reader, and set up electromagnetic shielding devices in key areas to ensure stable transmission and accurate reading of signals, and keep the reading accuracy above 99.9%.

(II) Data processing and storage pressure

With the generation of a large amount of real-time data, data processing and storage are facing tremendous pressure. Introduce high-performance edge computing devices and distributed storage systems, adopt data compression and screening algorithms, improve data processing efficiency, reduce storage costs, and ensure the real-time and integrity of data.

(III) Employee training and technology acceptance

Some employees may be resistant to new technologies or lack relevant skills. Develop a comprehensive employee training plan, including theoretical knowledge and practical operation training, and establish an incentive mechanism to encourage employees to actively participate in and master new technologies. The employee training coverage rate reaches 100%, and the technology acceptance rate is increased to more than 90%.

(IV) Industry standards and compliance with regulations

The semiconductor industry has strict standards and regulations for product quality and production processes. Ensure that RFID solutions comply with relevant industry standards and regulations, such as ISO 9001, SEMI standards, etc., and conduct regular internal audits and third-party certifications to ensure compliance.