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What is Semiconductor?

Content: Semiconductors are materials with electrical conductivity between that of a conductor (like metals) and an insulator (like ceramics). They have unique electronic properties that allow control over their conductivity. Semiconductor technology is utilized in simple devices like solar cells and LEDs, and more commonly in the manufacturing of chips, which are then processed into various electronic components. These include IC (Integrated Circuits), microprocessors in servers, memory chips, communication modules (like Bluetooth, Wi-Fi, mobile communication), and ABS (Anti-lock Braking Systems). Semiconductor technology is extensively applied across various fields, significantly contributing to advancements in modern technology.

A semiconductor, typically silicon, begins as a thin slice cut from a large single crystal ingot. The Czochralski process is often used to grow silicon ingots up to 450mm in diameter, which are then sliced into thin wafers. The size of wafers has increased over time, with 300mm diameter wafers now common in high-volume manufacturing. These wafers are highly polished for subsequent photolithography processes, where tiny components are etched at nearly atomic scale across the surface. Larger wafers allow for more dies per wafer, significantly reducing costs.

In the global context, semiconductor capacity is projected to reach new heights, with significant growth driven by advances in technology like generative AI and high-performance computing. The demand for semiconductors is rising across various sectors, including automotive, computation, data storage, and wireless technologies. This surge in demand and the strategic importance of semiconductor manufacturing are driving investments and innovations in the industry
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How the wafer is made?

Wafer processing

What's the difference between a wafer and a chip? A wafer serves as the initial material for manufacturing chips. It is a thin, circular silicon substrate typically made of single-crystal silicon. The wafer manufacturing process involves two main stages: the first stage, which includes wafer cleaning, crystal growth, ingot pulling, wafer slicing, and polishing; and the second stage, known as wafer fabrication, which includes processes such as vapor deposition, photoresist coating, exposure, developing, etching, photoresist stripping and final cleaning.

Wafer Cleaning
Wafer Cleaning
The wafer raw materials' surfaces are cleaned through high-temperature melting and solvents like HF hydrofluoric acid or KOH potassium hydroxide to remove contaminants and organic residues, ensuring excellent substrate quality.

Crystal Growth
Crystal Growth
High-purity silicon raw material, silicon dioxide, is placed into a furnace for refining, reducing it to metallurgical-grade silicon. After distillation purification, it undergoes a slow decomposition process to produce "polycrystalline silicon.

Ingot Pulling
Ingot Pulling
Polycrystalline silicon is melted with boric acid and phosphorus in a quartz crucible, and then, at high temperatures, a single crystal silicon rod (seed crystal) is immersed and pulled up while rotating. The silicon adheres to the seed crystal and solidifies evenly on the rod, forming a columnar single crystal silicon ingot.

Wafer Slicing
Wafer Slicing
The freshly produced crystal column has an uneven surface. It needs industrial-grade diamond tools for processing, removal of tapered ends, diameter adjustment, and cutting into wafer slices using high-hardness saw blades or wire saws.

Polishing & Lapping
Polishing & Lapping
After wafer dicing, the surface becomes rough and requires polishing and grinding. Polishing aims to make the crystal surface smoother and shinier, while grinding rounds the wafer's edges into a smooth curve.

CVD
CVD (Chemical Vapor Deposition) 
CVD is a process where gaseous precursors are introduced into a reaction chamber. When these gases come into contact with a heated substrate, they generate deposited materials, forming a thin film on the substrate's surface, used for creating insulating or conducting layers.

Photoresist Coating
Photoresist Coating
When exposed, photoresist undergoes a chemical change. Initially, a uniform photoresist layer is coated onto the wafer's surface, allowing it to be removed or retained in subsequent exposure and development steps, forming the desired pattern.

Exposure
Exposure
Using patterns on the photomask, expose the photoresist layer to ultraviolet light. Align the photomask onto the wafer coated with photoresist, causing a chemical reaction in the photoresist layer in the illuminated areas, initiating a photochemical reaction.

Photolithography
Photolithography
Exposing wafers to a developing solution (possibly containing alkalis like sodium hydroxide, potassium hydroxide, and additives) selectively removes unexposed areas of the photoresist layer, leaving behind a template in the exposed regions.

Etching
Etching
Using acidic or alkaline etching solutions, remove underlying materials based on the pattern on the photoresist layer, leaving the protected areas on the wafer surface (exposed photoresist areas) unaffected, shaping the microstructures of the chip.

Photoresist Stripping
Photoresist Stripping
After development, residual photoresist is removed through chemical, thermal, or mechanical methods, like stripping solution, to prevent adverse effects on device performance.

Final Cleaning
Final Cleaning
Finally, the chips undergo a secondary cleaning process, which may involve organic or inorganic solvents, surfactants, or ultrasonic cleaning techniques, to remove residual chemicals and particles from the manufacturing process, ensuring the produced chips are clean and meet specifications.

Application of Flow Meters and Nozzles in the Semiconductor Industry

Application 1: Monitoring Chemical Flow

In semiconductor manufacturing, precise control of chemical liquid flow is crucial due to the complex and delicate processes involved. Each step in the production process relies on accurate chemical supply and flow rates, impacting the final product's quality and stability. Liquid flow meters play a pivotal role in precisely controlling and monitoring fluid flow within pipelines, ensuring product quality and performance.

When transporting chemical agents from the central storage facility to various equipment, the use of flow meters allows for precise monitoring of the liquid quantity

Case: Chinese Technology Semiconductor Factory

Situation: Traditional factories without a central chemical supply system often transport various chemicals separately to different areas and equipment. This practice can lead to potential safety hazards and inefficiencies in optimizing chemical usage.

Solution: LORRIC FP-AS510 Paddlewheel Flow Meter
To address this challenge, we recommended the establishment of a central chemical storage room within the company's factory. During operations, chemicals are centrally delivered to each machine, and the FP-AS510 paddlewheel flow meter is used to accurately calculate the required quantities, reducing the cost of chemical losses during processes. The FP-AS510 paddlewheel flow meter, holding multiple international patents and certifications, features the patented AxleSense technology. Its waterwheel blade structure can detect extremely small flows as fluids pass through, achieving precise liquid measurement. The FP-AS510 also provides real-time monitoring capabilities for abnormal blade conditions, detecting zero-flow issues caused by blade disappearance. By installing the FP-AS510, the company can accurately calculate dosages for each machine during chemical preparation, resulting in cost savings. Furthermore, given the highly concentrated and corrosive nature of chemical agents, which can pose risks during storage and transportation, the use of FP-AS510 addresses this concern. The product is made of PVDF material, providing excellent resistance to solvents and acid-base corrosion, eliminating worries about chemical corrosion and leakage and enhancing workplace safety.

Application 2: Measurement and Monitoring of Ultra-Pure Water

In semiconductor manufacturing, a significant amount of ultra-pure water is used for wafer cleaning, rinsing electronic components, etching, and more. During the ultra-pure water treatment process, precise liquid flow measurement is often required. For instance, in the reverse osmosis (RO) process, measuring the flow rate of concentrate is crucial for controlling concentration ratios and preventing membrane scaling. Continuous monitoring of water flow also helps assess RO equipment performance, detecting potential faults or anomalies promptly. In the deionization (DI) process, ion exchange resin is used to remove ions from water, necessitating monitoring of flow rates through the resin and the flow rates of backwash liquids to ensure effective ion removal. Additionally, precise control of chemical dosage is required during the chemical addition phase of ultra-pure water processing, such as measuring the dosage of disinfectants (chlorine, chlorine dioxide, ozone) for microbial removal or pH-adjusting agents (sulfuric acid, sodium hydroxide) to maintain water quality stability. Therefore, ultra-pure water treatment operations demand highly accurate liquid flow measurement and chemically resistant measuring tools.

Monitoring liquid flow rates during deionization (DI) and reverse osmosis (RO) processes ensures water quality and equipment performance

Case: Taiwan's Leading Semiconductor Foundry

Situation: The company specializes in engineering water treatment systems, including ultrapure water systems, wastewater recycling, and wastewater treatment projects. During the ultra-pure water treatment phase, standard electromagnetic flow meters cannot be used because ultra-pure water is non-conductive. The company sought an ultrasonic flow meter solution, but common models on the market had challenging and cumbersome installation and setup procedures. They also required regular replenishment of ultrasonic gel, resulting in a suboptimal user experience. Additionally, the company needed a solution to precisely measure small liquid flows and ensure good chemical resistance during the ultra-pure water processing phase.

Solution: LORRIC's Ultrasonic Flow Meters
We recommended installing LORRIC's ultrasonic flow meters in the company's ultrapure water treatment equipment. These meters feature easy installation, bidirectional flow measurement eliminating flow direction concerns, a patented probe track for precise placement, and fasteners for secure fitting. This enhances flow accuracy, ensures stability, and allows non-destructive removal and maintenance, simplifying the installation process. LORRIC's ultrasonic flow meters utilize two sensors to measure ultrasonic wave frequency, calculating precise flow speeds. They are ideal for RO systems, monitoring high-concentration water through ultrafiltration membranes for stability, and DI processes, optimizing ion removal via ion exchange resins. These meters offer excellent chemical resistance, meeting specific requirements.

Application 3: Spiral Nozzles - Core Components in Semiconductor Exhaust Gas Treatment

semiconductor manufacturing, harmful gases (ammonia, sulfur dioxide, nitrogen dioxide, hydrofluoric acid, etc.) are generated as exhaust gases. Therefore, spiral nozzles are used in exhaust gas treatment towers to spray washing agents like alkaline solutions (sodium hydroxide) to neutralize acidic gases (ammonia) or acidic solutions (hydrofluoric acid) to neutralize alkaline gases (sodium hydroxide, ammonium hydroxide). This process converts hazardous substances into stable and manageable compounds, purifying the factory's emitted exhaust gases, ensuring compliance with exhaust gas treatment regulations, and promoting sustainable development goals.

The waste treatment tower employs nozzles to spray chemicals, converting hazardous substances generated during semiconductor manufacturing into stable and easily treatable compounds

Case: Leading Taiwanese Wafer Foundry

Situation: Nozzles from mainstream brands are primarily produced using plastic injection molding, creating nozzle models directly from molds. This manufacturing method limits the spiral nozzles' ability to have high-precision spiral surfaces and conical channels, resulting in smaller spray areas and less effective performance. Moreover, generic nozzles often use PP (polypropylene), which lacks strength and hardness, is prone to breakage, and has limited resistance to high-temperature chemical environments. These nozzles not only fail to achieve optimal spray coverage but also lack the corrosion resistance required for the semiconductor industry's waste treatment.

Solution: LORRIC Spiral Nozzles
LORRIC's spiral nozzles are manufactured through precision machining, carving materials into solid conical spiral-shaped nozzles. Their larger paths for foreign objects effectively prevent clogging by impurities, and their spray coverage is larger than that of other brands in the market, with angles of up to 170 degrees. Additionally, LORRIC's spiral nozzles are made of top-notch corrosion-resistant materials - UPVC (polyvinyl chloride) and PEEK (polyether ether ketone), prolonging the nozzle's lifespan in highly chemically reactive environments. They are the best choice for exhaust gas treatment in the semiconductor manufacturing industry.

 

References

  1. ^ What is a Semiconductor Wafer? - WAFERPRO
  2. ^ GLOBAL SEMICONDUCTOR CAPACITY PROJECTED TO REACH RECORD HIGH 30 MILLION WAFERS PER MONTH IN 2024, SEMI REPORTS - SEMI
  3. ^ Semiconductor Wafer Capacity by Geographic Region (2020) - Anysilicon
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