SiC Square Mirror Mirror-Grade Polishing for Lithography Machine
The Silicon Carbide (SiC) square mirror is a core precision
component in high-end semiconductor manufacturing and precision
optical equipment, such as lithography machines. It typically
serves as the key sensor substrate within the wafer stage scanning
and positioning feedback system. Its performance directly
determines the equipment's overlay accuracy, line width
uniformity, and production line yield.
The SiC square mirror's exceptional thermal stability,
lightweight yet high-stiffness structure, nanoscale optical surface
accuracy, and superior chemical stability make it crucial in the
most advanced fields like EUV lithography, space remote sensing,
and precision optical measurement. As semiconductor manufacturing
processes advance towards smaller nodes and space exploration
deepens, the performance requirements for it will become
increasingly stringent, driving continuous development in its
manufacturing and processing technologies.
SiC Square Mirror Key Material Characteristic Parameters
The following are the core material characteristic parameters
directly related to the performance of the SiC square mirror:
| Parameter | Typical Value/Range | Significance |
| Coefficient of Thermal Expansion | 2.7 - 4.5 × 10⁻⁶/°C | The lower the value, the better the thermal stability, minimizing
deformation caused by ambient temperature changes and highly
matching silicon wafers.
|
| Hardness | HV2500 (or Mohs 9.5) | Measures material wear resistance and ability to resist surface
scratching; high hardness ensures long life.
|
| Surface Roughness (Ra) | < 0.1 nm | Characterizes surface smoothness; smaller values are better,
forming the basis for high-quality optical reflection and imaging.
|
| Flatness | λ/50 (@13.5nm) or higher | Describes the flatness deviation of the optical surface; smaller
values indicate a flatter surface, crucial for imaging quality.
|
| Lightweighting Rate | 60% - 90% | Represents the percentage of weight reduction; high lightweighting
helps reduce motion inertia, improving motion accuracy and speed.
|
| Elastic Modulus | High (specific values vary greatly by process and structure) | Measures the ability to resist elastic deformation; a high elastic
modulus means high stiffness and resistance to bending.
|
SiC Square Mirror Key Features
1.Exceptional Thermal Stability: Silicon carbide exhibits an extremely low coefficient of thermal
expansion (CTE) (approximately 2.7-4.5×10⁻⁶/°C), which closely
matches that of silicon wafers. This enables it to effectively
resist thermal deformation and maintain dimensional
stability under temperature fluctuations.
2.Lightweight Design with High Stiffness: Through topology optimization, SiC mirrors can incorporate
honeycomb or hollow internal structures, achieving a
lightweighting rate of 60-90%. This significantly reduces their
own weight while maintaining high stiffness (high elastic
modulus) and a stable structural morphology.
3.Nanoscale Optical Surface: Utilizing advanced polishing techniques (e.g., laser-assisted
chemical mechanical polishing), the surface can achieve
mirror-grade finishing. The surface roughness can be
controlled to Ra < 0.1 nm, and the flatness can reach
λ/50 (@13.5nm) or higher, meeting extremely demanding surface
figure accuracy requirements.
4.Chemical Stability and High Purity: Manufactured from high-purity silicon carbide material, it
possesses excellent chemical inertness. It is resistant to
acid/alkali corrosion and plasma erosion, making it suitable for
semiconductor cleanroom environments and highly demanding optical
systems.
SiC Square Mirror Summary of Main Application Areas
Application Area | Key Application Details |
Extreme Ultraviolet (EUV) Lithography Machines | Key sensor substrate in the wafer stage scanning and positioning
feedback system.
|
High-Resolution Space Remote Sensing Satellites | Core component for space telescopes (mirror blanks) and earth
observation satellites.
|
High-End Optical Measurement & Detection Equipment | Provides reference plane in laser interferometers and precision
measurement systems.
|
High-Energy Laser Systems | Used for mirrors and mirror blanks in high-energy lasers.
|
Q1: What is a silicon carbide (SiC) square mirror and what is it
used for?
A1: A silicon carbide (SiC) square mirror is a
high-precision, high-stability sensor substrate primarily used
in the wafer stage scanning and positioning feedback system of
lithography machines, where its exceptional thermal stability and
nanoscale surface accuracy are critical for maintaining
sub-nanometer motion and alignment precision, directly impacting
overlay accuracy and line width uniformity in semiconductor
manufacturing.
Q2: Why choose silicon carbide for square mirrors instead of
traditional materials?
A2: Silicon carbide is chosen for its extremely low
coefficient of thermal expansion (CTE) (≈2.7–4.5×10⁻⁶/℃), which
closely matches silicon wafers to resist thermal deformation, and
its high stiffness-to-weight ratio, enabling lightweight
designs (e.g., honeycomb structures with 60–90% weight reduction)
while maintaining structural stability and durability under extreme
conditions.
Tags: # SiC Square Mirror, #Customized, #Silicon Carbide
Ceramics, #Mirror-Grade Polishing, #Lithography Machine
