Core Technology for Preparation of High Purity Ultrafine Silicon Micropowders for Semiconductors and Integrated Circuits: the Cornerstone Material to Empower the Chip Era

Abstract: As semiconductor integrated circuits (ICs) move toward nanoscale processes, the demand for high-purity ultrafine silicon powders, a key encapsulant material, has reached an extreme. This paper details the core preparation challenges and technical solutions for angular and spherical high-purity ultrafine silicon micropowders (SiO₂ ≥ 99.99%, Fe₂O₃ ≤ 0.0005%, particle size D50 0.5-5 μm) used in IC encapsulants, and ElevateSilica provides stable and reliable cutting-edge material preparation core technology and equipment to the industry by virtue of its innovative purification, ultrafine pulverization, and sphericalization technologies. ElevateSilica provides the industry with stable and reliable cutting-edge material preparation core technology and equipment.

I. Introduction: The "Invisible Guardian" of Chip Packaging

Driven by Moore's Law, semiconductor chips are becoming more and more integrated, and the line width is constantly shrinking. This is to protect the chip from the external environment damage to the epoxy plastic sealing material put forward unprecedented requirements. As the core filler material of the encapsulant, high-purity ultrafine silicon powder plays a key role as the "invisible guardian". Its purity, particle size and morphology directly determine the molding compound:

• Thermal conductivity: affects the thermal efficiency and stability of the chip.

• Coefficient of Thermal Expansion: It needs to be matched with the silicon chip and lead frame to prevent cracking caused by thermal stress.

• Dielectric Properties: Affects the integrity and speed of signal transmission.

• Package Density and Reliability: Finer particle size allows for higher fill rates to meet thin, high-density package requirements.

The ultimate in silicon micropowder for cutting edge applications:

• Chemical composition: SiO₂ ≥ 99.99%, Fe₂O₃ ≤ 0.0005%, while strictly controlling K, Na, Ca, Cu and other trace metal impurities.

• Particle size distribution: Strict sub-micron distribution is required, particle size D50 is usually between 0.5-5μm, and no oversized particles are required.

• Particle morphology: divided into angular silica micropowder and spherical silica micropowder with better performance.

Second, the core technical challenges in the preparation of high-purity ultra-fine silica micropowder

Converting natural quartz raw materials into silica micropowder to meet the above stringent standards requires breaking through a series of world-class technical challenges:

1. Ultimate purity challenge: to control the iron content of five parts per million (0.0005%) below, and to remove all trace impurities that may affect the performance of the semiconductor, the need for near-absolute purification capabilities.

2. Ultra-fine crushing and size control challenges: How to crush high hardness quartz down to the submicron level while avoiding process contamination, controlling energy consumption, and achieving a narrow and stable particle size distribution.

3. Spheronization Barriers: Converting irregular angular particles into perfect spheres requires extremely high temperatures (above 2000°C) and precise kinetic control to ensure high sphericity, no hollow balls, and a smooth surface.

4. Consistency and Stability: The semiconductor industry requires a high degree of consistency in the performance of batch-produced products, and any minor fluctuations may result in lower yields for downstream customers.

ElevateSilica's innovative core technology system

In response to these challenges, ElevateSilica has developed a complete technology chain covering " raw material purification → ultrafine crushing → precision grading → spherical modification ". 1.

1. Deep chemical purification technology: the cornerstone of purity

• Multi-stage pickling and complexing technology: Using special high-purity mixed acid system, under high temperature and pressure or ultrasonic assistance, the raw materials are leached in depth, effectively stripping the inclusions of impurities and surface metal ions. Especially for iron, the complexing agent is used for targeted removal, realizing the limit index of Fe₂O₃ ≤ 0.0005%.

• High-purity water washing and filtration: Use ultrapure water with a resistivity of 18 MΩ-cm or more to carry out multi-stage counter-current washing, and combine with precision filtration technology to completely remove acid radical ions and reaction products.

2. Ultra-fine crushing and precision grading technology: the art of particle size

• Non-pollution grinding technology: Adopting stirred mill or airflow mill lined with high-purity zirconia and polyurethane to ensure zero metal pollution in the process of ultra-fine pulverization.

• Multi-stage precision grading system: Integration of high-efficiency turbine grading and airflow grading technology, precise cutting of particle size distribution, effective removal of coarse particles (>5μm) and ultra-fine powders (<0.5μm), to ensure that the product D50 is concentrated in the target range, with a narrow and uniform distribution.

3. High-temperature sphericalization technology: a leap in performance (for spherical silicon micropowder)

• Energy efficient plasma spheronization technology: This is the core advantage of our technology. Utilizing a high temperature plasma torch (temperature can reach tens of thousands of degrees) to instantly melt the angular silicon powder particles, and naturally form perfect spheres under the action of surface tension.

  • Advantages: high spherization rate (≥95%), smooth and dense particle surface, no hollow ball; the reaction process is carried out in a closed environment, no secondary pollution; energy consumption is more advantageous than the traditional flame method.

• Precise temperature control and yield optimization: Through precise control of plasma power, feed rate and atmosphere, the melting state and cooling process of particles are optimized to ensure high yield and consistency.

4. Comprehensive quality control and inspection system

• We are equipped with laser particle size analyzer, ICP-MS (Inductively Coupled Plasma Mass Spectrometer), Scanning Electron Microscope and other advanced testing equipment to strictly monitor the purity, particle size and morphology of each batch of products to ensure that the products are in full compliance with semiconductor industry standards.

Fourth, the core value of ElevateSilica solutions

1. Break through the technical bottleneck: We provide not only a single device, but also a solution to the limit of purity, ultra-fine particle size and perfect spherical shape of the overall technical solutions to help customers break the situation of high-end materials rely on imports.

2. Customized production capacity: We can customize products with different particle size combinations (e.g. "large particle filling + small particle compacting" gradation design) and different sphericalization rates according to customers' specific plastic sealing material formulation requirements.

3. Excellent Economy and Stability: Mature and reliable process routes and independent research and development of key equipment ensure the continuity of production and product consistency, bringing long-term and stable economic benefits to customers.

4. Full-process support from laboratory to industrialization: We provide all-round technical support from kilogram-scale sample preparation to 10,000-ton production line construction, covering process design, core equipment supply, line integration and debugging training.

In the context of the national strategy of independent control of semiconductor industry, it is crucial to realize the localization of high-end packaging materials. As a key link in the industry chain, the preparation technology of high-purity ultrafine silicon powder has become an important symbol of a country's new material level, and ElevateSilica is committed to becoming an innovation engine in the field of semiconductor materials, and with the world's leading core technology of high-purity ultrafine silicon powder, ElevateSilica will provide domestic and foreign chip manufacturers with outstanding performance and stable supply of basic material solutions, and work together with them to provide the most comprehensive technical support in the field of semiconductor materials. Together, we will support the arithmetic cornerstone of the digital world.

Please feel free to contact our technical team for a detailed proposal and sample testing service on the core technology of semiconductor-grade silicon micropowder preparation!