Updated SOW High Uniformity Sputter Deposition Tool.pdf

STATEMENT OF WORK

HIGH UNIFORMITY SPUTTER DEPOSITION TOOL

Background

NASA Goddard Space Flight Center (GSFC) has stringent requirements on the properties of sputter deposited, thin-metal-film detector elements and wiring. Such requirements are met by manufacturing a high-vacuum deposition system for dc magnetron sputtering with robust, proven methods of meeting the thin film specifications.

Requirements for deposited thin-film thickness uniformity, purity, electrical quality and cleanliness must be met and demonstrably maintainable over many years with good production throughput and minimal maintenance / tool downtime. These elemental thin films are incorporated into x-ray focal planes and are planned for the NASA contribution to the x-ray detector for ATHENA X-IFU (Advanced Telescope for High Energy

Astrophysics Integral Field Unit) and other missions and opportunities. Parameters achieved by the thin films are determined by the configuration of the system as well as the performance and durability of the components and mechanisms used in the system.

Further, the system must be able to deposit on multiple substrates so that all substrates

(also called “wafers”) in a run have resulting metal films with near-identical electronic properties. As such, the vacuum deposition system for sputter deposition will be designed as a production level facility and be optimized for a specific process.

The thin films needed for NASA GSFC x-ray detector prototypes have several critical parameters that must be met by the equipment during acceptance by GSFC. These specifications include uniform thickness across four (4) four-inch substrates (or more) simultaneously deposited. This uniformity is 1% wafer-to-wafer as well as +/-2% or better within the active region of the wafer. The tool must further be designed to prevent incorporation of magnetic impurities down to the ppm level into the thin metal films as this is known to degrade the performance of detectors realized from the films. The system will be designed to produce thin films while minimizing incorporation of unwanted particles into the films. The design may include choices of coatings on the parts of the system that see deposition, cooling of electrodes and shielding, geometry of the chamber and other methods to mitigate particle incorporation. The system will be equipped with a loadlock to reduce the water and oxygen levels present in the deposition chamber to suitably low partial pressure levels that oxygen incorporation into the elemental films (of such materials as Nb, Ti, Mo, Al) are negligible. The ion source in the main chamber will be used for cleaning of the substrates prior to deposition. It is expected to be an RF source. The anticipated use of the tool is for loading either bare oxidized Si substrates or substrates with wiring layers buried under a capping oxide layer with micron-scale vias down to the wiring layer. The substrate will be precleaned followed by addition of Nb to a circuit as a wiring layer. The requirements for the Nb to be uniform thickness, stress tunable, reproducible, and low particulate apply to the sputtered layers made by the system.

If the proposed equipment can exceed the requirements for uniformity of film thickness, reproducibility, low contamination and durability/longevity listed here, the vendor should indicate the ultimate capability of the system as this will be considered in the technical appraisal. While one embodiment of this tool is described in this statement of work, other system configurations will be considered. Each configuration choice should be motivated from the perspective of the target specifications of the qualitative and quantitative characteristics of the thin films produced by the tool. The system will meet safety requirements of the GSFC facility including SEMI S2 and NFPA 318 compliance.

Objectives

Through this statement of work NASA GSFC will obtain a high vacuum system that achieves specifications for DC magnetron sputtering deposition of thin metal films of niobum and other elemental metals.

The specifications for the vacuum system to be obtained by NASA GSFC include strict limits on the minimum number of substrates, in situ substrate cleaning, thin-film thickness control and uniformity, and deposition conditions. Specifications are as follows:

The vacuum system will be capable of deposition on at least four 4” silicon wafers and achieve, for each wafer, the film thickness tolerance and other substrate conditions listed here.

The vacuum chamber will use a cryopump to achieve a base pressure below 1e-7 torr.

The vacuum chamber will maintain a background pressure of 3e-7 torr (excluding argon) during sputter deposition of Nb (to be checked via RGA before and after the deposition)

The vacuum system will be capable of magnetron sputter deposition of films of

Au with uniform film thickness (+/-2% across a 100 mm wafer, with 0.5 cm exclusion zone at the edge of the wafer, and +/-1% wafer to wafer).

If possible within the chamber geometry, a configuration for optimization of the deposited thickness uniformity (such as wafer rotation and planetary motion of the substrates) shall be able to be installed in the chamber to improve the thickness specification beyond the +/-2% level with a goal of +/-1% uniformity.

The main chamber of the vacuum system shall come equipped with an ion source capable of cleaning a pre-deposited thin film surface without depositing magnetic impurities onto the substrate. Plasma and ion beam sources will be considered.

The vacuum system shall come with non-magnetic (or consisting of magnetic materials, e.g. stainless steel), removable shields to protect the chamber walls, doors and ion source from deposition during evaporation.

The vacuum system will be capable of tuning the stress of the deposited films, in particular tuning Nb to near zero film stress (-100 MPa to 100 MPa).

The vacuum system shall be equipped with a UHV load-lock for automatic loading of 4”, 6” and 8” substrates. The load lock can be turbo or cryo pumped.

NASA GSFC will obtain a deposition system which is fully cleanroom compatible and compatible with the GSFC cleanroom facility including compatibility with all provided utilities (power, compressed gases, chilled water) and safety requirements of the GSFC facility.

NASA GSFC will obtain a system capable of depositions on 4”, 6” and 8” wafers.

NASA GSFC will verify film thickness uniformity prior to final acceptance of the tool.

NASA GSFC will obtain installation of the tool on site at NASA GSFC

NASA GSFC will obtain training on the tool once installed at NASA GSFC

NASA GSFC will obtain one year of support on the tool for achieving the specifications for the thin metal films as quoted by the vendor including improvements as needed to maintain achievement of the specifications (if they drift out of spec during the first year).

NASA GSFC will obtain a twelve month warranty on the system for all parts and labor to maintain the functionality of the tool as delivered to GSFC.

NASA GSFC will obtain a system meeting safety requirements of the GSFC facility including SEMI S2 and NFPA 318 compliance.

Scope

The vendor shall design the vacuum system to meet the specifications described in the

“Objectives” and “Task or Requirements” sections of this statement of work.

In the description made by the offeror, the tool shall be comprised of a proven design for robustness of production method and demonstrated ability to meet specifications over a long period of typical use with limited maintenance or downtime.

The vendor shall provide sufficient documentation of the design of the vacuum system to the NASA GSFC technical representative to gain approval of the design prior to construction.

The vendor shall proceed with the build of the vacuum system after getting approval from the NASA GSFC representative.

The vendor shall complete building of the vacuum system at their facility and hold the system at their facility until the NASA GSFC technical representative accepts the tool for shipment to NASA GSFC.

The vendor shall pack and ship the tool to NASA GSFC.

The vendor shall provide for installation of the tool at NASA GSFC.

The vendor shall provide for training of personnel on the tool at GSFC and provide all manuals and documentation pertaining to the operation and maintenance of the tool and its subcomponents.

The vendor shall provide and support a warranty of all components on the tool. If the tool has difficulty reproducing the specifications once installed at GSFC, the vendor shall provide support on the tool to establish end user processes that achieve the target specifications of the niobium thin films.

Tasks or Requirements

General

The vendor shall provide a system with all new construction and all new components.

No refurbished equipment will be accepted. No refurbished components or subcomponents will be accepted.

The vendor shall provide a DC magnetron sputtering deposition system with load lock meeting or exceeding specifications listed. The vendor shall prove through calculations and performance of past systems that the proposed system will meet all specifications.

The vendor shall provide a leak tight system (to <1e-9 scale on a helium leak checker), welded on all ports, ferrofluidic feedthroughs, and flanges that are conflat with copper gasket wherever possible.

The interior of the system will have polished vacuum surfaces. Regions of the system exposed to deposition may have suitable coatings to suppress particulate formation.

System and Pumps

The vendor shall provide a vacuum system with roughing pumps and cryopumps sufficient to pump the system to below 1e-7 torr.

The vendor shall provide a roughing pump with sufficient pumping speed that can be located away from the system and still pump the system to the required crossover pressure in a reasonable time (<30 minutes). The same roughing pump can be employed for the load lock and the main chamber. The preferred pump configuration is one in which the roughing pump is powered off after the roughing of the system or turbo-pumping of the load lock is completed to prolong the life of the pump.

The vendor shall provide a cryopump with 10” flange for the chamber that it can reach

1e-7 torr on an overnight pump and maintain good pressure in the tool (3e-7 torr) during deposition after a suitable bakeout. The preferred cryopump will have a fast regeneration method for when the pump needs to be cycled to room temperature. The cryopump will be mounted on the chamber to achieve maximum pumping speed but with appropriate protection against metal flakes and particles from getting into the chamber.

The vendor shall provide a feature for automatic regeneration of the cryopump.

The vendor shall provide a gate valve between the cryopump and the chamber that allows for maximum pumping speed of the cryopump to be achieved in the chamber. The vendor hall provide a loadlock gate valve that can be readily serviced.

The load lock shall be capable of reaching high vacuum with 2e-7 torr base pressure.

The load lock shall be automatic loading and be compatible with fixturing for 4” , 6” and

8” wafers.

The vendor shall provide suitable fixturing for using the automatic loading with 4”, 6” and 8” wafers

Chamber Configuration

The vendor shall provide a vacuum chamber with a throw distance (the distance from the sputter target to the substrate) in the 5-12 cm range. Vendor shall indicate the range of throw distances made available by the system.

The vendor shall provide a vacuum deposition chamber in which the deposited thin film uniformity is +/-2% across a 100 mm substrate (with allowance of a 0.5 cm exclusion zone at the edge of the wafer.)

The vendor shall describe the motion of the wafer during deposition and mechanisms required to achieve the motion through the plume of sputtered metal which in turn determines the achieved uniformity of the deposited layer. The chamber shall have a goal of a uniformity of +/-1% thickness with optimization of the deposition. The robustness of the proven design of the deposition method will be of particular consideration in the assessment of the tool description. For example, wafer rotation and planetary motion are proven ways of achieving tight film thickness uniformity tolerances.

The vendor shall provide a vacuum chamber capable of simultaneous (or sequential automatically loaded) deposition on 4 or more 100 mm (i.e., 4 inch) silicon substrates with near identical thickness and other thinfilm properties..

The vendor shall provide a mounting plate and mounting fixtures for the substrates, where non-magnetic, non-ferrous materials are in contact with the wafer surface or nearby the wafer such that, if they are eroded by the plasma clean, they do not incorporate magnetic impurities into the film or onto the wafer surface.

The vendor shall provide a gate valve matching diameter of the mouth of the cryopump for maximum pumping speed when the cryopump is pumping on the system.

The vendor shall provide all stainless steel, welded gas manifold for argon gas and vent gas (dry nitrogen) into the chamber. The manifold will include leak tight shutoff valves and, for the argon, a mass flow controller or automatically controlled needle valve for setting the argon flow to the ion source. Plumbing interior will be clean and non-contaminating.

The vendor shall provide fixturing for all required water cooling for operation of the tool and its components. This includes any water cooling to the pumps, sputter cathode and shielding, chamber walls, RF clean electrode and other power supplies, and substrate holder. Water cooling plumbing will be protected from erosion from ion source and metal fatigue to prevent formation of plumbing leaks. Chilled water is provided along with other utilities by GSFC as stated in the government furnished equipment section.

The vendor shall provide an all-metal, non-magnetic (and not consisting of high percentage of magnetic material like stainless steel) shutter for the sputter targets with rapid, reproducible open/close mechanism for reproducible depositions. The shutter will be designed to be taken apart and cleaned as needed.

The vendor shall provide pressure gauging for the tool including ion gauges for pressure below 1e-4 torr and thermocouple gauges or equivalent for pressures from atmosphere to

10 millitorr.

The vendor shall describe the strategy for particle mitigation in the design of the system including suitable coatings on parts exposed to the plasma and the deposition plume and cooling of the relevant system components to prevent excess heat in the system, thermally affecting the film deposited within the chamber. Thin films produced in the tool shall have no more than five particles per wafer deposited by the system identifiable by microscope inspection.

The vendor shall provide a chamber design with suitable shielding and cathode shutters to prevent cross contamination of targets and programmable, controllable access to deposition on the substrates.

The vendor shall provide an RF wafer clean in the main chamber of the system (not the load lock). RF plasma and ion beam sources will be considered. The clean shall be optimized for uniformity of clean of oxidized silicon substrates and low particulate incorporation onto the surface of the substrate. The government does not have a preference on the type of clean.

Power Supplies and electronics

The vendor shall provide all electronics and power distribution for operation of the sputter deposition power supplies and RF sputter clean power supply, pumps, valves, pressure gauge readout, temperature readout and all other operations of interlocks, computer control, automatic valve control, and other system features provided by the vendor.

The vendor shall supply automatic tuning networks for the RF electronics to eliminate reflected power in the plasma during the cleaning. RF ion beam clean will also be considered. The RF power supply shall be capable of RF clean with the ability to vary ion energy to optimize the clean. The clean shall be used to etch SiO2 and similar oxides on a planar or corrugated substrate at a variable rate of up to 5 nm/min.

The vendor shall supply a minimum of 2 DC power supplies for the cathodes that are capable of 0.1 to 10 kW power output.

Power to the tool must be 208V three-phase, max breaker size of 100A.

Cathodes

The vendor shall supply a minimum of three cathodes

The vendor shall provide cathodes of a shape that optimizes the deposition uniformity for the system designed geometry of the substrate to target. The preferred cathode is 5”x15” rectangular cathode.

The vendor shall provide instructions and system design for straightforward disassembly and replacement of cathodes and sputter targets into the cathodes. Ease of sputter target replacement is an important consideration in this tool.

The vendor shall provide cathodes with cooling of anode, chamber, and dark space shield that enables operation of the cathode without excess heating of the substrates or other interior surfaces of the system.

The vendor shall provide cathodes with compatibility with other types of power supplies including DC pulsed and RF power supplies.

The vendor shall provide spare sets of cathode shields (total of 3 spare sets for the 3 cathodes) so that shield sets can be dedicated to specific materials. The vendor shall identify shielding that needs to be modular in this fashion.

RF source for wafer cleaning

The vendor shall install an ion or plasma source for Argon ion cleaning of the substrates prior to or in between depositions. The ion source will be able to provide a uniform beam greater than the size of the substrates. The substrates can be rotated over the source to provide uniform cleaning of all substrates. The ion source must be able to clean the deposited niobium film without contaminating the film with magnetic or particulate impurities (< 10 part per million, >1 micron particles).

The vendor shall provide details on the line of sight of the ion clean to the sample to discuss how the mounting scheme prevents all magnetic and particulate contamination from getting milled toward the surface of the wafer during cleaning or any use of the ion source.

Mass flow controllers/Pressure control

The vendor shall provide three mass flow controllers for the tool calibrated for Ar, N2, and O2.

The Ar mass flow controller shall be capable of argon flow 10-500 sccm

The N2 and O2 mass flow controllers shall control flow between 5-100 sccm.

The vendor shall provide the capability for either upstream or downstream pressure control during the deposition. The system shall come equipped with an adjustable gate valve to throttle flow to the cryopump during the deposition.

Pressure gauging

The vendor shall provide ion gauges for readout of the base pressure and leak up rate of the system and the load lock.

The vendor shall provide pressure transducers for precision measurement of Argon in the millitorr range for pressure measurement before and during the sputter depositions and

RF cleans

Windows / Spare Ports

Window ports that can see the deposition plasma shall be protected by a shutter that can be manually operated by the user of the tool at the window.

The vendor shall provide at least 3 spare ports with 2-3/4” conflat for user applications.

Shields for walls and shutter

The vendor shall provide removable shields that protect the walls of the chamber. Since these shields may be in line of sight between the wafer and the plasma or ion beam cleaning source, shields should be made of or coated with Aluminum, Titanium, or some other low sputter yield, non-ferrous, non-magnetic-ion producing material.

The vendor shall provide a non-magnetic (or containing substantial percentages of magnetic materials) shield for the shutter or changeable components for the shutter that can be cleaned while the system continues to be operated.

Automatic Control / Interlocks

The vendor shall provide automatic valve control for pump, vent, and cryo pump regeneration. The vendor shall also provide for a maintenance mode wherein the valves can be accessed for servicing.

The vendor shall provide a computer interface for operation of the sputter cathodes including tuned matching network and RF sputter clean. It should readout and log pressure gauges, temperature monitors, and sputter parameters during a deposition run.

The vendor shall interlock the system so that, for example, the sputter cathode and power supply cannot be operated at high pressure, the roughing valve and gate valve cannot be actuated at the same time, etc.

Demonstrated System performance

The vendor shall demonstrate vacuum performance of the tool and functionality of all components. GSFC can provide substrates and targets if needed to complete the demonstration at the vendor facility. In addition to data logs showing the pumpdowns and equipment operations, films shall be produced and provided to GSFC for inspection.

The vendor shall demonstrate the remaining requirements on the thin films during installation and training at GSFC.

Spare Parts

The vendor shall provide spare parts for the sputter gun assembly.

The vendor shall provide a spare set of cathode shields for the chamber.

The vendor shall provide a list of consumables such as gaskets and hardware that fit the system

Safety

The vendor shall provide an emergency power off switch that is clearly labeled and accessible to users, posted warnings of high voltage as needed for the sputter and RF clean electronics, and a system the secures all hazards within the system. The system shall be interlocked so that if the hazards are open and accessible, the hazard cannot be actuated (for example, the sputter power supply cannot be turned on when the skins of the system are open and the area with the high voltage feedthrough is user accessible).

The vendor shall provide a system meeting safety requirements of the GSFC facility including SEMI S2 and NFPA 318 compliance.

Warranty

The vendor shall provide a one year warranty for all parts and labor for the tool and its components and subcomponents

Manuals

The vendor shall provide a full printed set of drawings of the tool, electronic schematics of the tool, and operation of the tool.

The vendor shall provide a parts list and operation and troubleshooting manuals for the components used in the tool

Shipping and packaging

The vendor shall provide for clean sealed packaging to protect the tool during shipment

The vendor shall provide for crating for transportation of the tool to GSFC and arrange for shipping, coordinating with the GSFC technical representative.

The maximum individual crate/package dimension so that it can fit into the DDL is 98”x

69.5”. Individual crate/package sizes must be less than that cross-section.

Upgrades

Substrate bias:

Substrate bias can augment cleaning and quality of thinfilm deposition (including tuning of the film stress). The vendor shall indicate whether the chamber configuration makes it possible to isolate the substrate fixture so that voltage bias of the substrate is feasible. If so, an upgrade to provide bias on the substrate shall be provided.

Substrate Temperature sensor:

The vendor may provide temperature sensing of the substrate as an option where the sensor is calibrated to +/-1 degree C in the range of 50-150 C.

Residual Gas Analyzer Upgrade:

The vendor shall provide an option for a residual gas analyzer with the tool capable of sensitive monitoring of hydrogen, nitrogen, oxygen, water vapor and other volatiles before, during, and after depositions.

High performance Cathodes and power supplies upgrade:

The vendor may provide upgrade to 17” MU high heat cathodes as an option. The vendor can provide options for upgraded power supplies include DC pulsed and RF power supplies

Spare Planets and Mounting Hardware upgrade:

Spare Planets and mounting hardware and rotational mechanisms – The vendor can provide an option for a second and third substrate holder that holds 6” and 8” substrates but does not meet the thickness uniformity.

Pump upgrade:

The vendor may provide options for a 60 cfm dry roughing pump and upgraded cryopump

Chamber bakeout upgrade:

The vendor may provide an option for a vacuum chamber bakeout including attached heater tapes and power supply or internal infrared heater lamps and power supply

Deliverables or Delivery Schedule

From Date of Award (DOA), the vendor shall provide a design for the system that meets the technical specifications. The design will include drawings of the proposed system as well as a parts list of all the components to be included in the system. In addition to the drawings and parts list, the vendor will provide supporting calculations to show that the technical specifications for film thickness will be met. (~ 1 month from DOA)

1.5 months from DOA: After approval of the design by the technical representative

(which will take ~0.5 months), the vendor shall provide a schedule for the build of the tool and acquisition of the parts list.

4.5 months from DOA: At this point (roughly halfway through the build of the tool), vendor shall provide an update against the schedule to show how the work is progressing.

7.5 months from DOA: At this point, vendor shall have completed the build and assembly of the tool. The technical representative will visit the vendor facility to operate the tool to produce initial baseline samples and accept the tool.

8.5 months from DOA: One month after acceptance, the vendor shall have installed the tool at GSFC and trained GSFC personnel on the tool.

Government-Furnished Equipment and Government-Furnished Information

NASA GSFC will provide utilities and cleanroom space for installation of the tool per specifications provided by the vendor for electrical power, compressed gases, chilled water, and any other required facilities.

Security

None

Place of Performance

The design and construction of the tool will take place at the vendor facility. The initial technical acceptance of the tool, including operation of the tool to deposit a thin metal layer will be performed at the vendor facility. The tool with be packaged and shipped to

NASA GSFC for installation. Final acceptance of the tool will be at NASA GSFC with the demonstration of a thin film meeting the thickness uniformity specifications. Training of personnel will also take place at NASA GSFC once the tool is installed.

Period of Performance

The period of performance for this order is from DOA through 9 months from DOA.