EHT Products for Semiconductor Fabrication
Highest Precision Ion Energy Distribution (IED) | Wafer Bias | Chucking | Plasma Generation
Unipolar and Bipolar| Tightly Controlled Wafer Voltages | Narrow Ion Energy Distributions (IED) | Small Critical Dimensions.
The EHT Semi plasma products achieve the highest semiconductor fabrication etch quality with precision control of the ion energy distribution (IED) at lowest minimum critical dimensions, yet with etching rates comparable to RF generators.
Our product range for semiconductor fabrications is summarized in the following table. Click any link for further information:
| Model | Applications | Uni- or Bipolar | maximums: | MHz |
| kV | kW | A |
| Spartan™ | Wafer bias, Chucking | Unipolar | 14 | 20 | 175 | 600 |
| Hoplite™ | Wafer bias, Chucking | Unipolar | 18 | 5 | 130 | 600 |
| Perseus™ | Wafer bias | Bipolar | 16 | 20 | 110 | 600 |
| Mid-Freq. RF™ | Wafer bias, Plasma generation | Bipolar | 25 | 100 | 3 кА | 1 |
| High-Freq. RF™ | Wafer bias, Plasma generation | Bipolar | 10 | 20 | кА | 15 |
EHT Semi products are designed for plasma generation and control during semiconductor fabrication. Our pulse generators are used to improve ion energy distribution control, bias surfaces, and chucking. Our RF generators are designed for direct drive of capacitive and inductive loads, eliminating the need for match boxes in plasma generation and surface bias applications.
Our semiconductor manufacturing product range features:
- Tailored waveforms
- Solid-state switching systems for integration into your tools
- Tightly controlled wafer voltages resulting in narrower ion energy distributions, which allows for increased control over process results including smaller critical dimensions
- Flexibility for multistate or multilevel operation (arbitrary number of states with fast transitions between states)
- Fast rise and fall times compared to RF sine-wave generators resulting in increased etch time per cycle
- No matching network is required, reducing complexity and size
- Very broad range of dynamically-adjustable pulse repetition frequencies.
EHT Semi Products for Wafer Bias
EHT Semi has developed several pulse generators for wafer bias in conductor etch, dielectric etch and atomic layer etch (ALE). These pulse generators allow you to optimize the bias voltage waveform on the wafer to precisely control the IED at the wafer surface to improve your etching process (especially the minimum critical dimension and etch rate).
EHT Semi Products for Plasma Generation or Wafer Bias
EHT Semi’s matchless RF generators can direct drive the capacitive or inductive load for plasma production or wafer bias. This direct drive ability eliminates the complexity of a matching network and allows the voltage, power, and duty cycle to be tunable in real time. We can design systems that operate at higher voltage and peak power levels compared to traditional RF generators. The higher power translates to faster etching. EHT has developed two classes of matchless RF generators, Mid- and High-Frequency.
The differences between bipolar and unipolar waveforms and the impact on IEDs are discussed in this tutorial.
All of our pulse generators can be customized, or we can build systems specifically for your application.
| Feature/Paremeter | Spartan™ | Perseus™ |
| Polarity | Unipolar positive | Bipolar |
| Maximum Vpk-pk | 16 kV into open load (>12 kV into simulated plasma load) | >16 kV into simulated plasma load |
| Wafer On-Time (per-pulse) | ~1.8ps | >1.6 µs |
| Max avg. DC input power | 20 kW | 25 kW+ |
| Power efficiency | 65% (into simulated plasma load) | 89% (into simulated plasma load) |
| Ion Current/Wafer Voltage Droop Compensation | Not implemented | Active Droop Compensation w/ energy recovery |
| Edge Ring Driver Compatibility | Separate Supply (e.g. Hoplite) | Separate Supply |
| Continuously Variable Multistate Operation | Yes | Yes |
| Size | ~7.5 ft3 (depending on configuration) | ~7.5 ft3 (depending on configuration) |
| Weight | ~125 kg (depending on configuration) | ~125 kg (depending on configuration) |
Product Landscape
The market for wafer bias products, plasma excitation, and RF generators is addressed by Advanced Energy with their eVoS LE and ME Bias Solutions, Comet pct, MKS Instruments, and Trumpf Hüttinger.
Potential users of our semiconductor plasma etching products include
- Compound Semiconductor Centre at Cardiff University
- European Semiconductor Manufacturing Company (ESMC) GmbH in Dresden. Announced under the framework of the European Chips Act, this is a collaboration between the giants Infineon Technologies AG, TSMC, Robert Bosch GmbH, and NXP Semiconductors
- Global Foundries, also in Dresden, was spun out of AMD according to the “TSMC model”, whereby capital intensive fabrication tools are used to make semiconductors for fabless customers such as Nvidia, ARM, AMD, NXP, Infineon, and ST, etc.
- IMEC
- Infineon Technologies, maker of semiconductors for a massive array of applications, particularly power switching and power management
- Intel in Magdeburg
- NXP in Germany and Austria, who make ARM microcontrollers, eg. EtherCAT via Hilscher, and asics for embedded computing in automotive, IoT & industrial solutions
- SPS International, manufacturer of plasma etching tools
- SPTS Technologies (a KLA company), also semiconductor etching using plasma
- ST Microelectronics, the very large maker of microcontrollers ie STM32
- Xfab, a specialty foundry for the analog world
