Amended NIST Requirements.pdf

NIST Requirements Horizontal Four-Tube Low-Pressure Chemical Vapor Deposition System

Background:

The National Institute of Standards and Technology (NIST)/Center for Nanoscale Science and Technology (CNST) enables science and industry by providing essential measurement methods, instrumentation, and standards to support all phases of nanotechnology development from discovery to production. The Nanofabrication Operations Group of the CNST has the mission of advancing measurement science by developing novel nanofabrication and nanomanufacturing techniques. NIST’s CNST NanoFab seeks to acquire a horizontal four-tube low-pressure chemical vapor deposition (LPCVD) system for installation into a class 100 multi-user CNST NanoFab cleanroom facility. The clean room facility is located at the NIST Gaithersburg, MD site and is used as a shared resource that is accessible to researchers from industry, academia, NIST, and other government agencies. The horizontal four-tube LPCVD furnace stack shall consist of two silicon-nitride, a TEOS and a low-temperature oxide (LTO) tubes. The added capability will allow us to deposit silicon nitride and silicon oxide dielectrics to be used as waveguides and cladding layers in nanophotonic and optomechanical structures. We will develop methods of depositing thin films with tailored material (stress/stoichiometry/refractive index) properties in the CNST NanoFab as a resource accessible to NIST and external researchers.

Scope:

NIST’s CNST NanoFab seeks to acquire a horizontal four-tube LPCVD system that will be used to deposit thin dielectric films to support a variety of NIST mission critical nanophotonics programs. The CNST NanoFab has numerous NIST mission-critical and external projects, including the NIST-on-a-chip nanophotonic efforts, that utilize thick dielectric cladding layers over their nanoscale fabricated photonic structures. The LPCVD system will allow for tailoring and optimizing of the stress, stoichiometry, density, optical constants, and optical losses of the deposited films, thereby allowing for the construction of high efficiency nanophotonic architectures. Dense, high-quality, stoichiometric silicon nitride films are utilized as waveguide layers in linear and non-linear photonic applications to support NIST mission critical timing applications such as chip-scale photonic-based clocks. The TEOS and LTO based oxides are used as cladding layers in nanophotonics. The horizontal four-tube LPCVD furnace system shall accommodate substrate sizes up to 150 mm semi-spec silicon substrates. The overall performance and the success of the numerous existing and future NIST mission critical projects carried out in the CNST NanoFab will depend critically on the ability to accurately deposit dielectric films in a horizontal four-tube LPCVD furnace system.

Minimum Requirements

The system shall meet or exceed the technical specifications identified below. NIST will not accept first articles or demonstration units. All materials shall be new. Rebuilt systems will not be considered.

Contract Line Item Number (CLIN) 0001: The Contractor shall provide one (1) horizontal four-tube low-pressure chemical vapor deposition system that meets the following minimum specifications:

1. The horizontal four-tube low-pressure chemical vapor deposition system shall consist of four processing tubes in the following configuration from top to bottom:

a. low-pressure chemical vapor deposition silicon nitride tube as the topmost tube.

b. low-pressure chemical vapor deposition silicon nitride tube.

c. low-pressure chemical vapor deposition tetraethyl orthosilicate (TEOS) tube.

d. low-pressure chemical vapor deposition low-temperature oxide (LTO) tube.

2. The horizontal four-tube low-pressure chemical vapor deposition system shall have the following footprint:

a. The overall length of the system shall not exceed 140 inches.

b. The overall width of the system shall not exceed 30 inches.

c. The overall height of the system shall not exceed 100 inches.

3. The horizontal four-tube low-pressure chemical vapor deposition system shall meet the standard to accommodate an installation in a class-100 cleanroom.

4. The horizontal four-tube low-pressure chemical vapor deposition system shall accommodate substrate sizes up to 150 mm diameter, semi-spec silicon wafers. Changing wafer carrier from one size to another shall not require retooling or changes to the furnace configuration. Furthermore, the wafer loading system shall support the processing of small irregular shaped wafer pieces up to 40 mm per side. This may be accomplished using a carrier fixture in a standard wafer carrier.

5. The horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with quartz hardware wafer boats with lids and the pick-up tools. Each furnace shall have 3 caged boat carriers (boats with a lids) and 3 pick-up tools. Two of the caged boats, each with a pick-up tool, shall accommodate loading of 100 mm diameter, semi-spec silicon wafers. The third, and last caged boat with a pick-up tool shall accommodate loading of 150 mm diameter, semi-spec silicon wafers. Each boat shall have slots to allow loading greater than or equal to 25 semi-spec silicon wafers.

6. All wafer carriers and piece holders supplied with the system shall be constructed from quartz.

7. The horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with the required vacuum pumping system. All required vacuum pumps shall be located in the CNST NanoFab subfab area beneath the process level approximately 15 meters (approximately 50 feet) away. The vacuum pumps shall be Edwards ixH610 dry vacuum pump or equivalent.

8. Each furnace stack of the horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with a wafer transport system and a source cabinet that contains all process gas panels.

9. Each furnace stack of the horizontal four-tube low-pressure chemical vapor deposition system shall allow processing up to 50 silicon wafers per process run.

10. Each processing tube shall be designed with a computer-controlled cantilever loading system. The cantilever system shall be designed to remain in the process tube under vacuum and base temperature at all times except when loading and unloading substrates.

11. Each furnace tube shall be equipped with a valved leak check port at the furnace level and vacuum pump level to facilitate vacuum troubleshooting.

12. Each furnace tube shall incorporate particulate traps, heated valves, and heater jackets where appropriate to minimize the accumulation of process effluent on vacuum system components.

13. All furnaces shall be capable of ramping to the set-point temperature at a rate of at least 10 degrees Celsius per minute. The furnaces shall be equipped with spike and profile thermocouples. All thermocouples shall be type R or type S.

14. Temperature control system shall be interlocked to prevent over temperature or run-away temperature conditions.

15. All furnace tubes shall have at least 3 temperature control zones.

16. The two low-pressure chemical vapor deposition must be able to deposit stoichiometric silicon nitride (Si3N4) films suitable for low-loss integrated photonics resonators, such as microring resonator geometries, that operate across wavelengths ranging from the telecommunications bands in the near-infrared to visible wavelengths. Stronger preference will be given to systems that can provide evidence of successful use of deposited films in high quality factor (Q>5x10^5) microresonators, including operation at different wavelength and for different film thicknesses. Such evidence can be a copy of relevant scientific or trade publication(s) or an internal report or reports presenting data recorded by the vendor. Demonstrated ability to perform this task is necessary because low-loss integrated photonics is one of the main focuses of the NIST mission critical research to be performed using the LPCVD furnace.

17. The two low-pressure chemical vapor deposition silicon nitride tubes shall meet the following requirements:

a. The two nitride furnace tubes shall have separate injectors for dichlorosilane and ammonia.

b. Thermal flat zone shall be greater than or equal to 457 mm (18 inches) with process control to less than or equal to a plus or minus 1 degree Celsius.

Temperature stability within the flat zone shall be less than or equal to a plus or minus 0.5 degree Celsius over a typical process run.

c. Tube shall have a minimum of three zones that are actively temperature controlled using digital temperature control units.

d. All furnace parts exposed to processing conditions shall be made of quartz.

e. Process tube shall be designed to run both stoichiometric silicon nitride and low stress silicon nitride recipes.

f. The nitride furnaces shall accommodate deposition temperatures up to 840 degrees Celsius.

g. For a processing batch of 50 semi-spec silicon wafers, the LPCVD stoichiometric silicon nitride films shall have the following characteristics:

i. The LPCVD stoichiometric silicon nitride films deposition rate shall be greater than or equal to 3 nanometers per minute and will provide films to build high-quality factor optical resonators.

ii. During the LPCVD of stoichiometric silicon nitride films, the total gas flow of dichlorosilane and ammonia shall be less than or equal to 200 sccm.

iii. Deposition pressure during the LPCVD of stoichiometric silicon nitride films shall be in the range between 200 mTorr and 350 mTorr.

iv. Residual stress of the LPCVD stoichiometric silicon nitride films shall be in the range between 1000 MPa and 1250 MPa.

v. 1-sigma standard deviation uniformity of the LPCVD stoichiometric silicon nitride films shall be less than or equal to 5 % across a 150 mm diameter wafer.

vi. Index of refraction of the LPCVD stoichiometric silicon nitride films shall be in the range between 1.98 and 2.1 (measured at the HeNe wavelength of 632.8 nm).

h. For a processing batch of 50 semi-spec silicon wafers, the low-stress silicon nitride films shall have the following characteristics:

i. The LPCVD low-stress silicon nitride films deposition rate shall be greater than or equal to 4 nanometers per minute.

ii. During the LPCVD of low-stress silicon nitride films, the total gas flow of dichlorosilane and ammonia shall be less than or equal to 200 sccm.

iii. Deposition pressure during the LPCVD low-stress silicon nitride films shall be in the range between 200 mTorr and 350 mTorr.

iv. Residual stress of the LPCVD low-stress silicon nitride films shall be in the range between 50 MPa and 300 MPa.

v. 1-sigma standard deviation uniformity of the LPCVD low-stress silicon nitride films shall be less than or equal to 5 % across a 150 mm diameter wafer.

vi. Index of refraction of the LPCVD low-stress silicon nitride films shall be in the range between 2.0 and 2.3 (measured at the HeNe wavelength of

632.8 nm).

i. Vendor shall provide standard recipes for stoichiometric and low-stress silicon nitride depositions that achieve the specifications for the deposited films listed in 17g and 17h above.

18. The low-pressure chemical vapor deposition TEOS tube shall meet the following requirements:

a. Thermal flat zone shall be greater than or equal to 457 mm (18 inches) with process control to less than or equal to a plus or minus 1 degree Celsius.

Temperature stability within the flat zone shall be less than or equal to a plus or minus 0.5 degree Celsius over a typical process run.

b. Tube shall have a minimum of three zones that are actively temperature controlled using digital temperature control units.

c. All furnace parts exposed to processing conditions shall be made of quartz.

d. TEOS precursor module shall be equipped with liquid level sensor.

e. For a processing batch of 50 semi-spec silicon wafers, the LPCVD TEOS films shall have the following characteristics:

i. The LPCVD TEOS deposition rate shall be greater than or equal to

20 nanometers per minute.

ii. The LPCVD TEOS process shall allow for deposition of films with thicknesses of up to 3 micrometers in a single run.

iii. 1-sigma standard deviation uniformity of the LPCVD TEOS films shall be less than or equal to 5 % across a 150 mm diameter wafer.

iv. Index of refraction of the LPCVD TEOS films shall be in the range between 1.41 and 1.46 (measured at the HeNe wavelength of 632.8 nm).

f. Vendor shall provide TEOS precursor usage data per run of a specific length using a recipe that meets our TEOS film specifications.

g. Vendor shall provide standard recipe for depositing LPCVD TEOS films that meet our TEOS film specifications.

19. The low-pressure chemical vapor deposition LTO tube shall meet the following requirements:

a. The LTO furnace tube shall have separate injectors for silane and oxygen.

b. Thermal flat zone shall greater than or equal to 457 mm (18 inches) with process control to less than or equal to a plus or minus 1 degree Celsius. Temperature stability within the flat zone shall be less than or equal to a plus or minus 0.5 degree Celsius over a typical process run.

c. Tube shall have a minimum of three zones that are actively temperature controlled using digital temperature control units.

d. All parts exposed to processing conditions shall be made of quartz.

e. For a processing batch of 50 semi-spec silicon wafers, the LPCVD LTO films shall have the following characteristics:

i. The LPCVD LTO deposition rate shall be greater than or equal to

15 nanometers per minute.

ii. The LPCVD LTO process shall allow for deposition of films with thicknesses of up to 3 micrometers in a single run.

iii. The LPCVD LTO deposition process shall take place in a temperature regime between 400 degrees Celsius and 450 degrees Celsius.

iv. During the LPCVD of LTO films, the total gas flow of silane and oxygen shall be less than or equal to 250 sccm.

v. 1-sigma standard deviation uniformity of the LPCVD LTO films shall be less than or equal to 5 % across a 150 mm diameter wafer.

vi. Index of refraction of the LPCVD TEOS films shall be in the range between 1.44 and 1.46.

vii. Residual stress of the LPCVD LTO films shall be in the range between -300 MPa and -200 MPa.

f. Vendor shall provide standard recipe for depositing low temperature oxide films that meet our LTO film specifications.

20. Each tube stack shall be equipped with a separate standalone computer control module that allows for modifying, selecting, running, holding and aborting deposition recipes.

Therefore, the horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with four separate computing modules with four screens that independently control the respective furnace tube.

21. The horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with an addition centralized computer that monitors and records all states such as idle and in-process for each tube.

22. The horizontal four-tube low-pressure chemical vapor deposition system shall be equipped with software that allows for recipe editing and saving. Furthermore, the system shall allow for the recipes to be backed up at a central computer and at the furnace terminal.

23. The system shall allow for recipe editing at the furnace terminal.

24. The system shall allow for editing “on the fly” during a processing run in the administrator level access mode. “On the fly” editing shall allow for changing any of the process parameters at any step during the processing run.

25. During a process run, processing recipes shall:

a. be autonomous with little or no user interaction with the furnace outside of loading and unloading of the furnace.

b. continue to run unless a problem is detected, in which case the system shall redirect to a hold or abort step.

c. not be allowed to continue unless the required safety and access interlocks for the system have been satisfied.

26. During tool operation, process parameters such as gas flows, pressure, temperature, recipe name, and process step duration and countdown of the step and total time shall be displayed on the main screen.

27. The software shall allow for monitoring and datalogging of all process parameters such as date and time stamped data of each process step for all furnace parameters including gas flows (in SCCM or SLPM), zone temperatures (in degree Celsius), pressure (in milliTorr or Torr), throttle valve position, foreline pressure, and other parameters. The software system shall allow for the end-user to change the time interval between data points during data collection, with a minimum interval of at least 10 seconds per data point. The software shall save the data-log files in CSV-based ASCII format. Logged data shall be user configurable for both idle state and recipe running state.

28. The horizontal four-tube low-pressure chemical vapor deposition system control software shall allow for:

a. Automatic recipe operation in operator mode.

b. Automatic and manual operation in administrator mode.

29. The electrical utility requirement for the horizontal four-tube low-pressure chemical vapor deposition system shall be standard US 480 Vac, 60 Hz 3-phase supply configuration.

30. The horizontal four-tube low-pressure chemical vapor deposition system shall allow for the following safety interlock features:

a. Each individual furnace shall have an input that NIST can connect-to which prevents recipe operation. NIST uses an equipment control system that allows only trained users access to equipment. The connection to each furnace will be a relay closure which takes a DC voltage from the furnace and switches it on and off at the furnace input. This input shall prevent recipe starts and cause an abort condition if disabled during a run.

b. The furnace stack shall provide an input which when active will stop the flow of all hazardous gases. This input shall be tied into the building toxic gas monitoring system and will be used during a gas detection to disable the flow of all toxic gases and oxygen.

c. Hardware and software interlocks shall be provided to prevent unsafe operation of the furnace system. Interlocks shall include but not be limited to:

i. Heater cabinet over-temperature.

ii. Lockout gas flow of hazardous gases while tube is open.

iii. Process gasses such as silane, oxygen, TEOS, dichlorosilane and ammonia shall not flow without being under vacuum.

31. The horizontal four-tube low-pressure chemical vapor deposition system shall have an uninterruptable power supply for the system controls.

32. The horizontal four-tube low-pressure chemical vapor deposition system shall have a minimum of 1-year warranty from date of government acceptance. The vendor shall repair or replace at its cost, any defective items without any additional cost to the government including travel, labor, parts, or any other expense.

33. The seller shell coordinate shipment and installation of the horizontal four-tube low-pressure chemical vapor deposition system with the end user. The seller shall provide an onsite install and process engineer for the installation and qualification of the horizontal four-tube low-pressure chemical vapor deposition system.

34. The seller shall provide training on the horizontal four-tube low-pressure chemical vapor deposition system for the end user. Training for up to 4 people shall be done at NIST at the time of installation. Training will include at least three days of detailed information to maintain, repair, and troubleshoot problems that can arise during normal operation.

35. Vendor shall provide list of included parts in recommended spares kit. If vendor offers different levels of recommended spares kits, provide information and pricing about all of them.

Delivery

Delivery shall be FOB Destination (or equivalent terms, such as INCOTERMS Delivered Duties Paid) are required and shall occur within the vendor's commercially available timeframe.

FOB Destination means: The contractor shall pack and mark the shipment in conformance with carrier requirements, deliver the shipment in good order and condition to the point of delivery specified in the purchase order, be responsible for any loss of and/or damage to the goods occurring before receipt and acceptance of the shipment by the consignee at the delivery point specified in the purchase order; and pay all charges to the specified point of delivery. The contractor shall deliver all Line Items to:

The National Institute of Standards and Technology 100 Bureau Drive, Building 220 Gaithersburg, MD 20899-1640

Installation

Following delivery, NIST will need 90 days to facilitize the furnace stack, and directly following, the start-up of the system shall initiate by the Contractor and meet contract specifications no later than 60 days after facilitization. Installation, at a minimum, shall include start-up and final gas line and electrical connection of the system, and demonstration of all specifications. Onsite installation and demonstration shall be done at NIST, Gaithersburg, MD- Building 215.

Training

The contractor shall conduct a 5-day training session for up to 4 CNST NanoFab staff members at NIST. The training shall provide a thorough demonstration of all system/solution functions, maintenance, data administration, and basic troubleshooting. The training shall be completed at NIST immediately after on-site qualification measurements that meet our specifications.

Warranty

The horizontal four-tube low-pressure chemical vapor deposition system shall have a minimum of 1-year warranty from date of government acceptance. The vendor shall repair or replace at its cost, any defective items without any additional cost to the government including travel, labor, parts, or any other expense.

Inspection/Acceptance

The horizontal four-tube low-pressure chemical vapor deposition system shall meet or exceed the minimum specifications described above. The seller shall coordinate shipment of the horizontal four-tube low-pressure chemical vapor deposition system with the end user.

Following Contractor installation, testing of the horizontal four-tube low-pressure chemical vapor deposition system will be performed on-site in the manner outlined below.

Semi-spec silicon wafers or semi-spec silicon wafers with dielectric films such as an insulating silicon dioxide layer, prior loading into the furnace, will be RCA cleaned in the following manner:

a) The wafers will be placed into a SC-1 clean mixture, consisting of ammonium hydroxide and hydrogen peroxide, for 10 minutes at 80 degrees Celsius.

b) Wafers will be rinsed in deionized (DI) water.

c) For processing of bare silicon substrates, the wafers will be placed into a room-temperature dilute hydrofluoric acid solution to remove native oxides, and then water rinsed.

d) The wafers will then be placed into a SC-2 clean mixture, consisting of hydrochloric acid and hydrogen peroxide, for 10 minutes at 80 degrees Celsius.

e) Substrates will be DI water rinsed and nitrogen dried.

f) We will program and run the automated recipe. The furnace tube will vent and unload the paddle with the quartz boat. The system will be in a hold step to allow for substrate loading. We then will place the substrates into the quartz boat and continue the process. When the process fully ends, the furnace will be in a hold step, until we manually continue the process to initiate the last step of substrate unloading. When the substrate unloads, we will then characterize the thin deposited films.

We will measure stress of the dielectric films by depositing films directly onto semi-spec, double side polished, prime grade silicon wafers using the CNST NanoFab stress measurement tool.

This will be accomplished with the use of a laser interferometric system to measure the curvature of the wafer before deposition. Following the deposition, we will measure the optical constants using spectroscopic ellipsometry. Then we will remove the dielectric material from one side of the wafer, and using the dielectric film thickness ellipsometry results, we will then remeasure the wafer curvature and calculate the film stress.

In addition to measuring the optical constants and stress of the deposited thin films, we will also measure the optical losses of bulk films using the prism coupler. We will also measure optical losses in stoichiometric silicon nitride waveguides with LTO and TEOS cladding layers. In this scenario, stoichiometric silicon nitride will be deposited on top of an oxidized silicon wafer with a 3-micrometer thick silicon dioxide layer. The nitride film will be lithographically defined using a combination of electron-beam and optical lithography in conjunction with reactive ion etching.

A cladding layer will then be deposited on top of the stoichiometric silicon nitride waveguides, the chips will be polished and placed into an optical setup to quantitatively measure the optical losses in the patterned waveguide structures.

Warranty

The horizontal four-tube low-pressure chemical vapor deposition system shall have a minimum of 1-year warranty from date of government acceptance. The vendor shall repair or replace at its cost, any defective items without any additional cost to the government including travel, labor, parts, or any other expense.

Payment Schedule

The Contractor shall be paid, in accordance with Net 30-day payment terms, upon receipt and acceptance of a proper invoice, in accordance with the following schedule:

1. 40% due with drawing approval from the COR.

2. 50% due with delivery

3. 10% due after acceptance.

4. The Government anticipates inspection will occur upon:

a. After the testing procedures set forth in this document have been completed