2015 Ulvac NE 950 EX RIE Etch System

• With process gases BCl₃, Cl₂, SiCl₄, CF₄, SF₆, C₄F₈, O₂, and Ar, this versatile ICP etcher is designed to etch GaN, sapphire, metals, ITO, SiC, AlN, ZnO and others  
• Patented ICP with magnetic confinement (“ISM”) provides higher plasma density at lower pressure to improve etch rate, uniformity and anisotropy.  

 • Patented star cathode distributes power evenly enhancing uniformity  

 • System automatically loads (3) 6-inch wafers from cassette to carrier  

 • Carrier is clamped to temperature-controlled cathode via heat exchange; individual wafers cooled with backside helium  

• L/L and transfer chamber share an Ebara roughing pump. Process chamber uses an Ebara roughing pump and 1000 L/s turbo.

The ULVAC NE950EX is a high-throughput Reactive Ion Etching (RIE) system designed for mass production in the compound semiconductor industry, especially for LEDs. It is also known as the APIOS NE-950EX. A version exists for single 300mm wafer processing as well, the NE-950EX-V. 

Key features

• High-density plasma source: The system uses an Inductively Coupled Plasma (ICP) source with a static magnetic field (ISM). This allows for a wider range of process control compared to conventional ICP systems.
• High throughput: The system's capacity is dependent on the wafer size being processed:
• 2-inch diameter wafers: 29 wafers per batch.
• 3-inch diameter wafers: 12 wafers per batch.
• 4-inch diameter wafers: 7 wafers per batch.
• 6-inch diameter wafers: 3 wafers per batch.
• A single 300mm wafer or three 150mm wafers can be processed in the NE-950EX-V version.
• Patented technology: It incorporates two ULVAC-patented inventions:
• ISM (Inductively Coupled Plasma with Magnetic field): For generating high-density plasma.
• Star electrode: A self-cleaning electrode that prevents deposited material from accumulating on the RF window.
• Reliability: The system's design emphasizes easy maintenance, stability, and reliability through the use of re-deposition prevention techniques. 

Typical applications

The NE950EX is used for dry etching a variety of materials common in compound semiconductor manufacturing: 

• Semiconductor materials: GaN, AlGaN, InGaN, AlN, InP, and other III-V materials.
• Optical materials: Sapphire for LED manufacturing, ITO, glass, and quartz.
• Metals and ceramics: Gold (Au), Platinum (Pt), Titanium (Ti), Tantalum (Ta), and Silicon Carbide (SiC).
• Other materials: Carbon, Diamond-like Carbon, and more. 

Operational principle

Reactive Ion Etching (RIE) is a dry etching technique that uses chemically reactive plasma to remove material from a substrate. 

• Plasma generation: Gas is introduced into a vacuum chamber and ionized by a radio frequency (RF) electromagnetic field.
• Ion bombardment: The wafer sits on an electrode that is biased to a negative voltage, causing positively charged ions from the plasma to accelerate toward it.
• Anisotropic etching: The directional nature of the ion bombardment, combined with chemical reactions from the reactive species, results in highly anisotropic (vertical) etching.
• Chemical and physical effects: The process combines chemical reactions at the surface with the physical sputtering effect of ion bombardment. 

Key components

• Vacuum chamber: The main processing area where the etching takes place.
• RF power supplies: The NE950EX's ICP-RIE design uses separate RF sources for controlling plasma density and substrate bias, allowing for greater control over the etch process.
• Gas delivery system: Precisely controls the flow of reactive gases (e.g., Ar, O2, N2, CF4, Cl2).
• Pumps and chiller: A vacuum pumping system maintains low pressure in the chamber, while a chiller provides temperature control.