Attachment 1-Sputtering Chamber Technical Specifications.pdf

Attachment 1 – Technical Specifications

“Autonomous Sputtering Tool – Main Chamber”

June 2, 2025

1. BACKGROUND

The National Renewable Energy Laboratory (NREL) is seeking a highly automated sputtering system to support the autonomous synthesis of nitride and oxide thin film materials.

The sputtering synthesis of thin-film semiconductors requires precise control over a high-dimensional space of experimental variables, including substrate temperature, pressure, gas flow, and power. These parameters must be finely tuned to achieve the desired material properties, which are usually validated through ex-situ analytical tools. This iterative synthesis and characterization process is typically time-consuming and labor-intensive.

Autonomous experimentation (AE) is an emerging approach that integrates automated deposition instruments with in-situ analysis, leveraging artificial intelligence (AI) to direct experiments in rapid, closed-loop cycles. By enabling real-time decision-making, AE can significantly accelerate materials discovery and development. Full equipment automation and in-situ characterization are two requirements for this approach.

Similarly, automating execution of ex-situ characterization data collection and analysis would enable an even richer autonomous data stream for hands-off decision making. Ex-situ characterization in a closed AE loop additionally requires automated sample handoff from the deposition instrument to the external handling robot.

In this overall framework, including automated sputter deposition chambers, wafer handling robots, and in-situ and ex-situ closed-loop measurements, AE algorithms can efficiently identify, execute, and learn from experimental sequences. A key requirement for the success of this framework is the full automation of, and open data streams for, all tools, both deposition and in-situ characterization, as well as ex-situ processing and measurements, allowing AI to control experimental variables-based data received from instruments.

2. OBJECTIVE

The objective of this purchase is to enable AE synthesis of nitride and oxide materials to support the Minerals to Materials Supply Chain Research Facility (METALLIC), as part of an autonomous semiconductor development facility at NREL. The proposed solution will be subject to the NREL Technical Monitor’s approval and subsequent discussion about integration with the external robot arm.

3. OVERVIEW

NREL is seeking a highly automated sputtering tool to support its autonomous semiconductor development laboratory. The system must include in-situ instruments for plasma and film property measurements and be capable of integrating with an external autonomous mobile robot for wafer handoff and further transport to ex-situ characterization tools. The robotic wafer handling will be covered under a different purchase, so a) NREL will work with the sputtering tool vendor to ensure dimensional compatibility, and b) NREL expects the sputtering tool vendor to work/cooperate with the robot/automation vendor in this effort. High-level Application Programming Interfaces (APIs), communications, and data transfer protocols must be available for controlling and monitoring both the sputtering process and in-situ plasma/film measurements. The tool should adhere to standard sputtering practices for nitride and oxide materials, including vacuum integrity, cleanliness, source management, shutter operation, substrate heating, metrology, and baking. NREL prioritizes on-site maintenance whenever possible, so the system should be designed for self-serviceability. Additionally, flexibility for future research directions is highly valued.

4. CAPABILITIES

4.1. Vacuum Chambers

4.1.1. Required

• Growth chamber and load lock with automated transfer system between the two. Transfer system should be capable of realignment in case misalignment occurs. 0.02 mm positioning repeatability or better.

• Base pressure of less than 1E-7 Torr in growth chamber at typical operating temperature (600 °C).

• All components must be compatible with reactive sputtering (nitrogen and oxygen).

• Oxygen/nitrogen compatible vacuum gauges and heaters up to 800 °C.

• Relevant growth chamber pumps for reactive sputtering, most likely a combination of turbopumps and cryopumps, with relevant safety interlock mechanisms.

• Sufficient backing/roughing pumps to support main and load lock chamber and application.

• Appropriate windows (with shutters if on the growth chamber) and lighting needed for inspection.

• Easy‐to‐maintain gate valves (e.g., VAT valves) with computer/automated control. Gate valve with automated/computer control for regulating chamber pressure.

• Load-lock with a multiple-wafer cassette (e.g. 12) for fast sample loading, with a pumping system.

• Integration with an external robot for sample/cassette loading and handoff will be required as specified below.

4.1.2. Strongly Preferred

• The system should be designed with future expandability in mind, including the ability to interface with an additional processing or characterization chamber.

This includes compatibility with in-vacuum transfer to and from an adjacent chamber.

• The transfer arm and load lock must support future upgrades to enable integration of an additional chamber.

4.1.3. Preferred

• Main chamber and load-lock baking capabilities.

• Additional variety of spare ports though the chamber

4.2. Substrate

4.2.1. Required

• Up to 4” diameter substrates, with computer-controlled (on/off) continuous rotation, compatible with the automated transfer mechanism between load lock and process chamber.

• Heater capable of achieving 800 °C on the surface of a 4” diameter substrate platen. All components must be stable at 800 °C in a reactive environment (preferably manufactured from Haynes 230 alloy), including a suitable controller.

• 10–20 °C temperature uniformity across the substrate.

• Computer control of heater on/off, setpoint and ramp rate.

• Automated substrate rotation, z-position adjustment, and loading/unloading from/to load lock.

• Whole substrate shutter with computer/automated control.

• RF substrate bias with computer/automated control.

4.2.2. Strongly Preferred

• Substrate rotation position indexing. The indexing system must allow the substrate to rotate to specific, controllable angular positions to selectively expose different regions of the wafer.

• Substrate stage with masking capability to expose a small portion of the substrate (0.5-1.5” opening), such as an additional shutter blade with a window placed as close as possible to the substrate to minimize shadowing. The substrate would rotate beneath this fixed mask using the indexing system, enabling exposure of selected wafer areas to distinct processing conditions. The position of the exposed substrate area relative to the sputter guns remains unchanged.

4.2.3. Preferred

• Ability to accommodate up to 6” diameter substrates while maintaining 4” substrate compatibility.

• Heater controller with auto-tuning capabilities of its control parameters.

• Process gas (Argon (Ar)/Nitrogen (N2)/Oxygen (O2)) injection at the substrate with computer/automated control.

• Direct Current (DC) substrate bias, with remote-controlled switching mechanism between Radio Frequency (RF) and DC biases.

4.3. Sources

4.3.1. Required

• 4 x 3” confocal magnetron sputtering sources, in sputter up orientation, with automated tilting capabilities to adjust ion fluxes to the substrate, including automated on/off shuttering according to recipes.

• RF excitation and matching networks for each sputtering source. Data recording/export and computer/automated control required.

• Computer-controlled process gas (Ar/N2/O2) injection individually routable to each source.

4.3.2. Strongly Preferred

• 1 source suitable for liquids, e.g., metallic Gallium (Ga.), on a retractable flange that can be valved off from the main chamber and pumped out independently.

• Etching source integrated in the main sputtering chamber (electron cyclotron resonance etching or inductive coupled plasma etching, ≥10 nm/min etch rate), independent of all the other sputtering sources.

• Alternatively, the etching source can be mounted on the same retractable flange as the metallic Ga source, so that the two can be manually switched out when needed, for two independent modes of operating the chamber (with Ga source or with etching source).

4.3.3. Preferred

• DC and pulsed DC excitation sources with data recording/export and computer/automated control as additional excitation options.

4.4. Robotics Integration Capabilities

An off-the-shelf collaborative robotic arm (“cobot”)—procured separately from this Purchase Order (PO)—will be responsible for the delivery and retrieval of wafers to and from the chamber load-lock(s). Examples of cobot manufacturers include, but are not limited to, Universal Robots, ABB, and Kuka; these examples are provided for illustrative purposes only and do not imply any specific vendor requirement. The chamber vendor may recommend an appropriate end-of-arm tooling solution for wafer handling, including technical drawings and pictures. Accordingly, the load-locks and wafer holders must be designed to accommodate robotic handling and be compatible with the selected cobot’s capabilities. Close collaboration between the selected chamber vendor and the selected automation/robotics provider will be critical to ensure seamless integration of the robotic arm with the chamber for efficient wafer transfer operations. NREL staff will coordinate and facilitate communication between the selected vendors to support this integration.

4.5. In-situ Instrumentation and Ports

Each in-situ instrument described below should be included in the quote as an optional feature, and if not included, the chamber geometry must be able to accommodate the required equipment.

4.5.1. Plasma Characterization

4.5.1.1. Required

• Langmuir probe with computer/automated control.

• Ion energy analyzer with computer/automated control – for example, Neocera’s Ion Energy Spectrometer (IES-200) or Impedans’ Quantum System.

• Optical emission spectroscopy (OES) with computer/automated control: proper positioning of optical collimators on each sputtering source and at the substrate level.

4.5.1.2. Preferred

• Camera for spatiotemporal plasma monitoring with computer/automated control, with a set of wavelength bandpass filters (“color wheel”) to capture the spatial distribution of chemical species in the plasma in different spectral sub-bands.

• High-resolution optical spectrometer (Echelle spectrograph) with computer/automated control for substrate-level monitoring.

4.5.2. Film and Process Monitoring

4.5.2.1. Required

• Real-time measurement of film temperature and wafer macroscopic mechanical properties (e.g., stress, curvature, etc.) Data acquisition, exporting, and computer/automated control are required.

4.5.2.2. Strongly Preferred

• Optoelectronic characterization, such as photoluminescence. Data recording/export and computer/automated control required.

4.5.2.3. Preferred

• Structural measurements or vibrational spectroscopy, such as Raman integrated with photoluminescence using the same excitation laser.

4.5.3. Ports and Doors

4.5.3.1. Required

• Required ports and flanges to support all instrumentation above.

• Spare ports for future expansion of in-situ instrumentation.

• The load-lock door must be computer-controlled and automated for easier robotic access.

4.6. Software and Control

4.6.1. Required

• Programmable Logic Controller (PLC)-based control, with all PLC control routines authored in structured text.

• The system must be fully automated with computer control, such that it is compatible with an autonomous operation paradigm, where no human intervention is necessary.

• Computer control of all process parameters, including, but not limited to, individual sputtering sources, Mass Flow Controller (MFC) setpoints, process pressure, heater temperature, ramp rates, shutters, sources tilting, and substrate height.

• Computer control of all process pumps and valves for regular operation (as opposed to maintenance)

• Computer control of sample transfer between process and load-lock chambers.

• Automated venting and opening of load-lock chamber to atmosphere, so robot can deliver and fetch platens.

• Every software-accessible variable and command shall be exposed through a single standardized protocol or API. Acceptable options include Modbus Transmission Control Protocol (TCP), Open Platform Communications (OPC) Unified Architecture (UA), and Message Queuing Telemetry Transport (MQTT). Proprietary or closed protocols are not acceptable.

• Real-time data stream of all chamber control and measurement variables.

• Comprehensive documentation of all software components, APIs, and underlying data structures, including detailed error-handling strategies and recovery procedures.

• The software and control solutions must be scalable and adaptable to future process enhancements without requiring major redevelopment.

• Five-year support, including software updates, bug fixes, and technical assistance for the data and control interfaces.

• Compatible with 64-bit Windows 11 system.

4.6.2. Strongly Preferred

• Open-source, Python-based control software, with complete user- and developer-level documentation and end-to-end code examples.

• Native Python PLC client library for issuing commands, reading status variables, subscribing to events and alarms, etc., with sample scripts demonstrating common workflows (recipe upload, live-data visualization and recording, error recovery, etc.).

4.6.3. Preferred

• Integrated control of in-situ instruments with corresponding data acquisition.

• Customizable human-machine interface.

• Computer control: minimum 16-thread CPU, 16 GB RAM, 500 GB SSD, and a CUDA-compatible GPU with at least 6 GB of VRAM.

o The system should include multiple USB 3.0+ ports, o At least 2 available high-speed Ethernet ports.

4.7. Electronics, Acceptance and Safety

• Electronics rack(s) sized to contain all necessary components.

• PLCs and controllers must support structured text scripting.

• High quality power supplies which are easily replaceable in case of failure.

• Manual control of all process variables must be achievable in case of software failure.

• Easy access to electronics rack to enable troubleshooting.

• Emergency power off button.

• Interlocks that put the entire system in a safe state in case of unforeseen equipment or facilities failure.

• Capability to operate the entire system in manual mode for troubleshooting and maintenance.

• Compliance with strict national laboratory safety requirements. All components must pass NRTL certification either before delivery or the supplier must arrange for NRTL certification after installation and commit to fixing any issues found.

Additionally, the supplier must accommodate a site visit by a member of NREL’s facilities team, for the purpose of verifying electrical compliance of the equipment.

• Uninterruptible power supply (UPS), capable of supporting critical systems for at least 30 minutes.

• A quantitative on-site acceptance protocol of the instrument, with a sequence of quantifiable tests on each subsystem, component and their interaction.

• Chillers, if required, must be capable of handling the full water flow and pressure differentials required by the system operating at full capacity.

Delivery and Installation

NREL requires finalized design drawings by August 31, 2025, and delivery and installation of the tool by September 30, 2026.