SOW for Electron Beam Lithography tool-vs2 Final.pdf

STATEMENT OF WORK FORMAT

Electron Beam Lithography Exposure System

PCN:

Background

The GSFC Detector Development Laboratory (DDL) has a requirement to acquire an electron beam lithography (EBL) system. The EBL system is used to define nano-sized geometric structures needed in the fabrication of advanced sensors, detectors, optical and micromachined components.

The EBL is an essential tool for advanced device fabrication projects under development and in production in the Detector Systems Branch at GSFC. In particular, this equipment is critically needed for the technology development and production of detectors such as Microwave Kinetic Inductance Detectors, Transition edge sensor detectors, Magnetic Calorimeters. The EBL is a critical technology enabling optical components from the X-ray and extreme ultra-violet and visible to Far-IR/Sub-mm optical components.

Finally, the EBL will enable advanced fabrication processed supporting development of superconducting amplifiers and other electronic components, which are important to Goddard’s lines of business.

Objectives The objective of this project is to procure an electron beam lithography exposure system.

Scope The scope of this work includes production and delivery of the electron beam lithography tool. The EBL consists of an electron source or gun, a column, a wafer chamber, a vacuum system, a computer and associated control electronics, and an environmental chamber.

The electron gun is the source for an electron beam that is accelerated by a high voltage focused and positioned by electromagnetic and electrostatic lenses located in the column.

The electron beam is used to expose a layer of polymer (photoresist) on a wafer which is used as a mask to create nanoscale features necessary for advance components under development in the Detector Development Laboratory. The wafer chamber contains a sample handling stage for loading and unloading and unloading wafers and/or photomasks through a vacuum load lock, and for positioning the sample during processing. The vacuum system maintains vacuum in the gun, column, and wafer chamber during operation and during sample loading and unloading. The computer controls all aspects of the vacuum system, control electronics, lenses, electron beam blanker, and wafer position as well as computer aided design (CAD) data and processing recipes as well as computational software used to simulate the response of the photoresist and other materials for optimal writing of nano to micron scale patterns on the wafer. The environmental chamber houses the EBL system. It provides a stable environment for the electron beam and the wafer during operation.

Tasks or Requirements

The Supplier shall insure that the EBL is equipped with the following equipment and meet the following requirements prior to Acceptance of System:

1. EBL Overview

1.1. A brand new unit with at least 10 similar units working in field; no used equipment or accessories, listed below, are acceptable.

1.2. A standalone electron beam lithography tool is required. A converted scanning electron microscope will not be accepted for this procurement.

1.3. The EBL shall meet current industry standard (SEMI S2) requirements for safety including the use of Emergency Off (EMO) panic buttons. The tool shall include the appropriate shielding and interlocks for hazardous areas, protecting the user and maintenance personal from high voltages, pneumatics, radiation, moving parts and the tool from potential service failures.

1.4. The tool shall include all hazardous labeling in English

1.5. The tool shall be housed in a self-contained environmental chamber or cabinet with main body dimensions such that it will fit on a vibration slab < 3.35 m x

1.79 m. The cabinet shall have removable panels that enable trained maintenance personnel and Supplier technical representative access to the EBL mechanisms. The cabinet shall be less than or equal to 2.25 m tall.

1.6. The weight of the EBL shall be less than or equal to 1500 kg.

1.7. The total power consumption of the tool including vacuum pumps, and chillers shall be less than 3.75kW.

1.8. The EBL shall be compatible with a Class 100 clean room and all exposed parts cleaned at the factory to remove dust, grease, or debris.

1.9. The EBL shall include all necessary software and hardware to enable automated control of movement and alignment of wafers as well as exposure dose, electron beam focusing and control of the lithography patterns.

1.10. The supplier shall provide technical support of the equipment.

2. EBL Optics

2.1. The EBL system shall include a Schottky ZrO/W thermal field emission electron source capable of providing beam currents between 50 pA and 40 nA at beam energy between 10kV and 50kV. The field emission source shall have demonstrated lifetime of minimum 5000 hours at optimal performance. Beam current stability shall be < +/- 0.2% per hour.

2.2. The EBL shall be digitally configurable with column voltages between 10kV and 50kV for optimization of write field size and minimum feature size operations.

2.3. The EBL shall be capable of printing minimum size features less than or equal to 8 nm for both isolated lines and spaces.

2.4. The system shall include a pattern generator enabling printing speeds of 50 MHz with minimum pixel dwell time of 20 ns.

2.5. An electrostatic beam blanker shall be provided with tail free blanking and demonstrated rise times of 30 - 50 ns or better.

2.6. The pattern generator shall include a digital analog converter with 20-bit resolution position accuracy on the sample enabling 0.5 nm resolution on a 500 micron writefield at 50keV acceleration voltage.

2.7. Beam position stability shall be demonstrated less than 120 nm/8 hours within a +/- 2 oC stable room environment.

2.8. The EBL shall incorporate an InLens deflector for minimal feature distortion.

2.9. A user selectable exposure writefield on the wafer shall meet area requirements of up to 0.5 mm x 0.5 mm at 50 kV and 2.4 mm x 2.4 mm at 10 kV.

2.10. Stitched writefields pattern placement accuracy shall be demonstrated less than or equal to |mean| + 3sigma = 30 nm in a 500 um writefield. And shall be less than or equal to |mean| + 3sigma = 20 nm in a 100 um writefield.

2.11. The EBL shall be capable of both automatic and semiautomatic detection and alignment using up to 8 alignment marks formed in either polymer photoresist or metals within a writefield. Automated overlay accuracy shall be demonstrated less than or equal to |mean| + 3 sigma = 25 nm in write fields up to 500 um.

2.12. The EBL shall utilize both global (wafer level) and local (write field) alignment marks.

2.13. Global and local alignment mark recognition shall allow shapes such as crosses circles and user defined polygons for manual semi-automatic and automatic mark detection. The EBL shall enable use of up to 8 user defined alignment marks within a given write field.

2.14. The EBL shall incorporate an automatic stigmator, focus, and distortion correction and shall include continuous dynamic stigmator, focus and distortion correction using pixel by pixel writefield mapping on the fly across the entire writefield.

2.15. The EBL system shall include both an electron backscatter detector and a secondary electron detector for imaging of alignment marks and other features on the wafer. The electron detectors shall enable imaging of samples independent of electron beam writing applications such as for sample metrology (section 4.11)

2.16. The pattern generator shall be upgradeable to FPGA based 50MHz with full speed PCI-e bus interface.

3 Sample handling

3.1 The interior of the wafer chamber shall be greater than or equal to 450mm

(length) x 300 mm (width) x 500 mm(height) and shall be capable of processing 100 mm, 150 mm and 200 mm wafer diameters requiring minimal fixturing conversion times of less than 2 hours by a trained user. Wafer fixture holders shall be available from the vendor.

3.2 The system shall include a universal fixture for holding and processing of wafers and piece parts smaller than 100 mm diameter.

3.3 The system shall be capable of printing photomask reticles up to 180 x 180 mm as well as smaller photomask sizes. Fixtures for photomasks sizes 125 x 125 mm and 150mm x 150mm shall be provided by the vendor.

3.4 Dedicated fixtures for handling 100 mm diameter wafers shall be included with the tool. The tool shall be upgradable to accommodate 150 mm and 200 mm wafers with dedicated sample fixtures. The Supplier shall provide pricing information on 150 mm and 200 mm wafer fixtures with the quote.

3.5 Photomask and wafer fixtures shall provide pre-leveling functionality. The EBL shall provide 3 point sample tilt correction of less than 1 micron within the full travel range.

3.6 All sample fixtures shall include an integrated Faraday cup. The tool shall include a low noise integrated pico-ammeter for monitoring beam current.

3.7 The wafer stage shall provide a travel range of 150 mm x 150 mm and enable translation speeds up to 2 mm/s in the lateral X in Y directions.

3.8 The wafer stage shall provide travel range of greater than or equal to 20 mm in the Z direction.

3.9 The wafer stage shall operate with frequency stabilized laser interferometer closed loop control and demonstrated position accuracy of 1 nm with 0.5 nm step sizes over the full lateral X,Y travel range. Mechanical stage movements shall be updated at 8kHz frequency and 50kHz update frequency for beam tracking.

3.10The EBL shall be capable of measuring the height of the sample surface for automated dynamic focus adjustment. Height sensing repeatability shall have demonstrated reproducibility of 1 micron with a travel range of 2 mm in Z axis.

3.11 The tool shall provide an automated vacuum load lock system for exchange of wafers while minimizing the effect of sample changes on the ultra-high column vacuum.

4 Computer interface and associated software

4.1 The EBL shall include a computer interface for control of the system and logging of all process and machine state parameters as well as for imaging acquisition modes.

4.2 The computer interface shall control all operation of the tool including exposure dose, focus, wafer alignment, astigmatism, local fine alignment, global pre-alignment, wafer load and unload.

4.3 The computer interface shall provide secure login for users and tool owners with customer defined access to tool functionality, enabling less experienced EBL users to operate the tool safely.

4.4 The computer interface shall provide maintenance and setup programs for calibration, testing and recording tool functionality and performance.

4.5 The computer interface shall be compliant with NASA IT specifications. The supplier shall agree to work to a reasonable extent with NASA to meet IT requirements including IPV6 or provide necessary information and documentation should waivers be requested.

4.6 The computer interface shall include an exposure recipe editor. The recipe editor shall provide full automatic, semi-automatic and manual control of all EBL functions. The computer interface shall keep a log of all process recipes and internal hardware diagnostics run on the system recording all faults, errors, and unusual conditions.

4.7 Software shall provide all required data fracturing for specifying electron beam energy dose as a function of position on the sample.

4.8 The software shall calculate proximity effect correction (PEC) for position dependent dose modulation based on user input CAD geometry files. PEC algorithms shall automatically divide the geometric pattern into substructures and assign the correct dose to each. PEC shall include CAD data post-processing features like grow, shrink, frame, and double exposure overlap removal. PEC calculations shall include integrated simulation for inspecting patterns with respect to calculated proximity effects. The energy deposition and resist profile simulation shall incorporate user defined materials thickness and photoresist contrast. The simulation shall include a cross section view which provides visual estimation in a color map or 3-dimensional side view of the expectable results of process after exposure.

4.9 PEC parameters shall be selected from a user modifiable database of material parameters and/or shall be calculated based on Monte-Carlo simulation. The simulation shall take into account the acceleration voltage, resist thickness and substrate materials with a layered structure. The PEC shall include parameter determination using lookup table for standard substrates such as silicon and common materials such as silicon, nitrides, oxides, and various metals such as aluminum and gold.

4.10 Software shall provide the optional capability to expose in grayscale mode. The grayscale mode shall enable exposure patterns to be set by user input bitmap (BMP/TIF) files. The bitmap exposure mode shall enable the processing of photoresist contrast curves to enable variable dose grayscale lithography.

4.11 The EBL software shall provide the user access to importing, editing and exporting of CAD geometry in GDSII formats.

4.12 The EBL software and hardware shall provide a scanning electron microscopy inspection mode for device metrology. This feature shall provide automated wafer navigation via user defined CAD geometry files and automated scanning electron imaging and measurements of feature sizes as a function of position on the wafer. Measurements of feature geometry, including automated feature edge detection via secondary electron or backscatter electron signal amplitude shall be available. Software shall provide output reports of measured data and digital image acquisition features including noise reduction modes such as pixel averaging and frame averaging.

4.13 The systems software and hardware shall enable the user to input calibrated image data of the wafer surface that enables the EBL software to accurately navigate location on the sample.

4.14 The EBL software shall enable writing modes including single pixel lines, dots, circles, polygons in vector scan mode, meander scan, and line scan.

4.15 The EBL software shall enable advanced fixed beam and periodic beam modulation synchronized to a moving stage during exposure such that large patterns greater than the 500 micron write field can be printed without stitching errors due to write field shifts.

4.16 The fixed beam with moving stage shall demonstrate a line length of 1 mm with 120nm width +/- 10nm and mean deviation of linewidth less than 5nm and straightness deviation < 10nm.

4.17 The periodic beam with moving stage shall demonstrate a periodic pattern and two gratings (200nm pitch and 200.5nm pitch) in a 2 mm x 2 mm. The stripe accuracy of the grating shall be |mean|+3σ ≤ 20 nm. The Pitch control (accuracy and uniformity) shall be better than 200 nm ± 0.2 nm for the 200nm grating and

200.5 nm± 0.2 nm for the 200.5 nm grating.

4.18 Software automation shall provide an interface to PYTHON for scripting capabilities for improved throughput of unattended batch writing jobs.

4.19 The vendor shall provide at least one off-line software license for processing exposure and metrology jobs independent of the EBL system enabling parallel processing of new writing jobs while the EBL tool is writing patterns.

4 Vacuum System

4.1 The EBL shall include a vacuum system with demonstrated base pressure of 10-9 mbarr in the gun section, 10-6 mbarr in the specimen chamber.

4.2 Vacuum pumps shall be provided by the vendor including ion getter pumps for the gun region, turbomolecular pumps and dry vacuum pre-pumps for the column and specimen chamber. Associated vacuum gauges monitoring pressure for each section of the tool shall be provided by the vendor.

4.3 The vacuum system shall have standard recipes and procedures to enable high temperature bakeout of the ultra-high vacuum sections of the EBL.

4.4 Associated pumping and venting of the sample loadlock vacuum chamber shall be automatically controlled via the EBL software.

5 Facilities

5.1 The EBL and all required associated electrical components shall operate from

208V 30A and 60Hz three-phase plus neutral power. The supplier shall provide a transformer or other electrical components (to be installed by GSFC technician) to accommodate alternative electrical requirements.

5.2 The tool shall meet performance specifications when housed in a clean room environment with nominal temperature of 20 – 25 C +/- 2C, with temperature variations of less than 0.5C/hour, with relative humidity between 30% and 65%.

5.3 The EBL shall produce less than 1.2kW of heat dissipation.

5.4 The EBL shall require clean dry air < 1MPa, at 30L/min during sample exchange and less than 1L/min during normal operating conditions.

5.5 The EBL shall use dry nitrogen for venting the tool vacuum system and load locks.

5.6 The supplier shall provide a laboratory site survey to verify environmental conditions in the GSFC laboratory.

5.7 The Supplier shall provide environmental mitigation of AC and DC electromagnetic fields up to 60 mG from 0.5 Hz to 5 kHz with reaction time within 100 micro-seconds that could affect the electron beam positioning stability and accuracy. AC and DC fields shall be compensated on all three axis (X,Y and

Z). Active field cancelation shall be integrated within the system shield or environmental chamber.

5.8 The Supplier shall provide an uninterrupted power supply with autonomy time of up to 30min.

5.9 The Supplier shall provide shipping and crating information as well as engineering drawing information for required GSFC facilities hookups. The Supplier shall provide engineering drawings for requirements of assembly area if the tool requires on-site assembly prior to installation. The supplier shall provide environmental conditions for storage of the tool prior to facility installation. The supplier shall communicate facilities installation requirements to GSFC technical representative including electrical power, gases, vacuum and other utilities needed for operation.

4 Installation and Training

4.1 The price of the system shall include installation and calibration at Goddard Space Flight Center (GSFC). Installation at the GSFC shall include a demonstration that the tool is functioning within compliance and within specifications. The demonstration shall a vendor generated qualification report documenting the performance of the system.

4.2 The price of the system shall include crating and delivery of the instrument to Goddard Space Flight Center along with any customs or tariff fees.

4.3 The contractor shall provide oversight of GSFC supplied rigger for movement of EBL equipment into laboratory.

4.4 The supplier shall provide all necessary labor and personnel for installation and parts assembly of the EBL at GSFC. GSFC technicians shall provide all facilities connections for the tool as specified by the supplier.

4.5 The supplier shall inform GSFC of the required number and sizes of wafers as well as photoresist process requirements and metrology requirements for onsite testing and verification of conformance at least 45 days prior to delivery of the system.

4.6 At the completion of installation and demonstration, the Supplier shall provide on-location operational training to at least 3 GSFC engineers at GSFC.

5 Documentation and Warranty

5.1 A full set of all written documentation shall be provided. This shall include user manuals or equivalent as well as copies of any software, and any manuals for the software included with the system. This documentation shall be received by GSFC with the system hardware.

5.2 The Supplier shall offer GSFC a minimum of one year warranty for Parts and Labor. The vendor shall provide options for extended warranty if available under standard commercially available terms. The warranty period will begin upon acceptance of the system.

Deliverables or Delivery Schedule

Deliver complete specified system (as described above) and in accordance with the below deliverables table.

Item No. Deliverable Delivery Date Delivery Method

1 Final design configuration of

EBL

__10_ days after contract award

Electronic Format/ Contracting Officer’s Representative (COR)

2 Site survey 3 months after award

Supplier visit GSFC laboratory to verify environmental conditions (vibration, acoustic, electric fields)

3 Functional test of EBL tool at contractors facility

_7 months after contract award

Electronic Format/Contracting Officer’s Representative (COR) with in-person trip contractor facility to verify the test.

4 Delivery of tool to GSFC __1_months after acceptance of functional test

5 Assembly, installation and acceptance Test of Tool at GSFC facility

1 month after delivery of tool to

GSFC

Demonstration of performance functionality at GSFC facility

6 User Training for EBL tool operation

1 months after delivery of tool to

GSFC

Demonstration by technician at GSFC facility

Set up and install all components at GSFC Detector Development Laboratory.

1. Demonstrate system with specified performance/acceptance criteria (described above). Acceptance of system will be conditional upon successful demonstration of functions.

2. Equipment warranty on parts and labor for at least one year.

3. The contractor shall crate and ship the approved unit to Goddard Space Flight

Center, Building 30, 8800 Greenbelt Road, Greenbelt Maryland 20771

Government-Furnished Equipment and Government-Furnished Information No Government-furnished equipment (GPE) and Government-furnished information (GFI) will be required

Security

The Supplier will make every effort to provide a US Citizen for the installation and training at GSFC. If a US citizen is not available and a foreign national is required by the supplier to assist in the onsite installation at GSFC, the Supplier shall provide security information for badging purchases to NASA at least 30 days prior to expected visit.

Foreign nationals shall not work hours outside of 9am to 5pm on GSFC Center and shall not be granted access for more than 30 days in a calendar year.

Place of Performance The construction of the electron beam lithography system shall be performed at the Supplier’s facilities.

The Final Acceptance, Installation and Training shall be performed at NASA/GSFC, Greenbelt, Maryland.

Period of Performance

10 months after contract award.