SiO2 Dry Etching Process (RIE or ICP-RIE)

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Material Properties and Applications of Silicon Dioxide (SiO2)

Silicon Dioxide (SiO2) is an oxide of silicon. Depending on the purity and crystalline form, there are several types of products available including Quartz, Fused Silica and  Borosilicate Glass.

SiO2 has unique chemical and mechanical properties including excellent abrasion resistance, good electrical insulation and low thermal expansion and high thermal stability.

For device fabrication, this material has been used for several purposes, deposited by plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD).

• Passivation
• Insulation layer
• Etch stop of a silicon-on-insulator (SOI) substrate
• Hard mask for dry etching
• Substrate of microfluidics

Periodic Table (SiO2)

SiO2 Etching for Hard Mask Patterning

SiO2 mask has some advantages over photoresist. The mask shows higher etch selectivity especially when etching metals and hard materials such as silicon carbide (SiC). Also, it does not cause burning in high stage temperature compared to the photoresist.

SAMCO has provided SiO2 etching solutions for hard mask patterning.

Mask patterning of SiO2 on InP substrate was performed using a reactive ion etching (RIE) system. The etched profile showed vertical and smooth surfaces.

Etch Rate : 21 nm/min
Etch Selectivity : 1.46 (over photoresist)

SiO2 mask fabrication
SiO2 hard patterning

High-rate SiO2 Etching

High-rate SiO2 etching is one of the process requirements of customers in wafer fabs.
SAMCO has developed high-rate SiO2 etching process by optimizing the process recipe.

High Speed SiO2 Etching

Etch Depth : 30 µm
Etch Rate : 500 nm/min
Etch Mask : Cr

High Rate SiO2 Etching

10 µm width L/S pattern
Etch Depth : 11.2 µm
Etch Rate : 560 nm/min
Etch Selectivity : 2.0 (over photoresist)

High Rate SiO2 Etching

Etch Depth : 150 µm
Etch Rate : 400 nm/min
Etch Mask : Ni

SiO2 Microlens Fabrication

SiO2 microlens are key components of optical MEMS devices. SAMCO offers fabrication processes of SiO2 microlens, combining with SiO2 plasma-enhanced-chemical-vapor-deposition (PECVD) processes.
Height and profile angle can be adjusted by recipe optimization. Also, the etched profile shows smooth surface.

Glass Microlens

 Photo courtesy of AIST Kansai

SiO2 Etching for Microlens Fabrication

 Etch Rate : 100 nm/min
Etch Selectivity : 1.2 (over photoresist)

Glass Microlens Fabrication

SiO2 Nanoscale Etching

SiO2 nanoscale etching is required for fabrication of nano-electro-mechanical-system (NEMS) devices and nano photonic devices.

SiO2 anti-reflection film of moth-eye structure was created combining with PECVD, dry etching and subsequent wet etching. The SiO2 film was periodically patterned in less than 1 µm pitch.

Photo courtesy of AIST Kansai

SiO2 anti-reflection film

System Lineup for SiO2 Dry Etching

RIE Systems

– High etch uniformity over the wafers

RIE System for SiO<sub>2</sub> Dry Etching


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ICP Etch Systems

– ICP plasma source for fine SiO2 dry etching process

ICP Etch Systems for SiO<sub>2</sub> Dry Etching


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  • Dry Etch System for AlGaAs etching

Customer Publication

 SAMCO’s SiO2 plasma etching technologies are used for fabrication of various types of devices including microfluidics and MEMS devices.

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