##### General Scope and Description 

NASA Glenn Research Center has a requirement for two wet processing
stations and a clean workstation for the silicon carbide crystal growth
facility.

One wet processing station will be used for cleaning silicon carbide
crystals. One wet station will be used for cleaning quartz tubes and
quartz pieces used with processing silicon carbide crystals. Due to
space requirements and the unique layouts of installed equipment, each
of these stations will need to be a custom fabricated unit. The work
area within each of these stations shall be of laminar flow design. The
desired layout of features shall be located as specified in figures 1
and 2. Figure 3 depicts the required dimensions and locations for
cutouts in the clean workstation.

##### Wet Processing stations

##### General

The wet processing stations shall be designed to provide a laminar flow
class 100 clean working environment within the hood enclosure. The
stations shall be designed to meet or exceed current OSHA standard
1910.1450. Wet stations (items 1 and 2) shall be certified to the
requirements ASHRAE 110-1995 for the protection of individuals who will
be working with these stations. The wet processing stations shall meet
or exceed the requirements of FM-4910 of 1996 and ISO 2000 14644-1 & 2
(formally FED STD 209E). Both wet processing stations shall be
manufactured suitable for use in corrosive environments.

###### Materials Description

All polypropylene (polypro) materials shall be free of visual and
structural defects and shall meet the requirements of ASTM D-4101-02
Group1 Class 1 Grade 11.

## Construction Wet Stations

1.  Units shall be constructed with no exposed metals.

2.  Basic material of construction shall be 100% white, stress-relived,
    acid-resistant polypro.

3.  The hood structure shall use at least 3/8 inch thick polypro
    material.

4.  Work surface shall be at least ½ inch polypro and located between 34
    and 36 inches above the floor.

5.  Work surface shall be segmented such that the work surface can be
    removed for period cleaning or maintenance.

6.  The first 4 to 5 inches inside of the sash shall be perforated
    polypro to contain spills and assist with exhausting of the tub
    enclosure. The remaining work surface shall be solid polypro.

7.  A leak tight tub shall be installed under the entire work surface as
    secondary containment.

8.  Tub shall drain to a 1½ inch drain plumbed to the rear with exhaust
    ports connecting to exhaust system.

9.  All joints shall be thermally welded; leak tight and unions shall be
    flush.

10. Units shall be free standing and of a one-piece design.

11. Wet stations shall have a sloped front (6.5 to 7.5 degrees) away
    from the operator for ergonomic comfort.

12. The work surface shall be exhausted across the surface and shall be
    adjustable with louvered shutter(s).

13. The exhaust plenum shall be located at the rear of the wet station.

14. The exhaust duct collar shall be located at the top of the exhaust
    plenum.

15. The wet stations shall be provided with fluorescent lighting with a
    flow through design so as not to disrupt laminar flow of clean air
    and shall be located at the top of the working area within the wet
    stations.

16. The safety sash shall provide full viewing of the work area and
    shall be vertical rising with counter balanced plastic encapsulated
    weights.

17. The safety sash shall close to within at least one inch of work
    surface.

18. The work surface shall have a 1 to 1 ½ one-inch drip lip to contain
    spills.

19. Storage area under the work area shall be liquid leak tight to
    contain spills.

20. Plumbing and utility connections shall be accessible from the front
    of the wet stations by way of doors or removable panels.

21. A Minihelic pressure gauge shall be installed such that the HEPA
    filter(s) are monitored for loading.

22. HEPA filter units shall be located at the top of the wet stations
    and shall be fitted with prefilters.

23. An exhaust failure alarm shall be incorporated into the design.

24. Each wet station shall have at least one emergency power off switch
    fitted with a clearly labeled red mushroom head button and shall
    require a manual reset.

### [Wet Processing Station 1 (Figure 1)]{.underline}

1.  The width of this station shall be 66 inches +/- ½ inch.

2.  Station shall have two HEPA filter units with filters and prefilters
    30L x 24W x 3D inches +/- ½ inch in length, width and depth.

3.  Station shall have one Teflon N2 gun that is retractable and shall
    be installed in the middle front portion of the work deck as
    depicted if figure 1.

4.  One general-purpose sink, Polypro construction 16L x 16W x 12D
    inches +/- ½ inch in length, width and depth.

5.  General-purpose sink shall be located as depicted if figure 1.

6.  General-purpose sink shall be plumbed to hood rear with a polypro
    ball valve on drain and shall have a handle extension to the front
    of the station.

7.  General-purpose sink shall have one DI water faucet and shall be of
    a gooseneck design constructed of polypro and shall be fitted with a
    remote on/off valve located on the front of the station.

8.  Station shall have two duplex electrical receptacles, GFI protected,
    110-120 VAC, 60Hz, installed on hood front with fume tight covers.

9.  Station shall have one Teflon DI water hand spray that is
    retractable and shall be installed in the middle front portion of
    the work deck as depicted if figure 1.

10. Station shall have a hot plate well with a hot plate mounted such
    that the top surface of the hot plate is flush (within 1 inch) with
    the work surface.

11. The hot plate well shall be located as depicted if figure 1.

12. There shall be at least 1 inch but not more than 3 inches between
    the sides of the hotplate well and the hot plate.

13. Hot plate shall not be less than 7L x 7W inches and not more than
    10L x 10W inches.

14. Hot plate shall have a smooth stainless steel heating surface and
    integral stirrer.

15. Hot plate well shall have lip exhaust to provide local capture of
    fumes.

16. The hot plate shall have a digital temperature controller for
    controlling the temperature of the hot plate surface and shall be
    accurate to within +/- 5°C.

17. The station shall have a dry well 12L x 6W x 12D inches +/- ½ inch
    in length, width and depth for the storage of waste chemicals and
    shall be fitted with a flush fitting cover.

18. The dry well shall be located as depicted if figure 1.

19. The dry well shall have a drain to the hood tub.

20. The station shall have a DI water cascade rinse tank consisting of
    two stages with each stage measuring 6L x 6W x 8D inches +/- ½ inch
    in length, width and depth with overflow weirs and shall have an
    adjustable DI water flow inlet that drains to the hood tub.

21. The cascade rinse tank shall be located as depicted if figure 1.

22. The station shall have a variable laminar flow and exhaust volume
    system to control laminar flow exhaust volume from 90 lfm with the
    sash open, with a near linear reduction to 50 lfm with the sash
    closed.

23. The variable laminar flow and exhaust volume system shall provide an
    analog signal for output to (NASA supplied) external exhaust fan
    speed controller to maintain a negative pressure within the work
    zone.

> **Options**

Price separately as options to wet station number 1 the following
equipment.

1.  A deck mounted single wafer spin rinser/dryer manufactured from
    solid polypro material with at least an 8.5 inch bowl-shaped process
    chamber, digital process controller to control speeds up to 3000
    rpm, fitted with a drain and nitrogen port, lid. The spinner shall
    have a built in safety feature such that rotation shall come to a
    stop if the lid is opened. The spinner shall be designed to
    accommodate a single two inch wafer or 2 inch wafer segments of
    irregular shape. It is acceptable to have multiple wafer chucks to
    accomplish holding single wafers and holding wafer segments.
    Chuck(s) shall grip wafer or wafer segments by the edge in order to
    allow for complete rinsing. The drain shall be plumbed to the rear
    of the wet station. The spinner rinser/dryer shall be located as
    depicted if figure 1.

2.  A point of use hot DI water heater capable of delivering at least
    0.65 gpm that shall be plumbed to a separate Teflon DI water hand
    spray that is retractable and shall be installed in the middle front
    portion of the work deck as depicted if figure 1. A tee with
    separate ball valve shall be included to allow for hot DI water to
    be plumbed to a second wet processing station.

### [Wet Processing Station 2 (Figure 2)]{.underline}

1.  The width of this station shall be 66 inches +/- ½ inch.

2.  Station shall have two HEPA filter units with filters and prefilters
    30L x 24W x 3D inches +/- ½ inch in length, width and depth.

3.  Station shall have one Teflon N2 gun that is retractable and be
    installed in the middle front portion of the work deck as depicted
    if figure 2.

4.  One general-purpose sink, Polypro construction 12L x 16W x 10D
    inches +/- ½ inch in length, width and depth.

5.  General-purpose sink shall be plumbed to hood rear with a polypro
    ball valve on drain and shall have a handle extension to the front
    of the station.

6.  General-purpose sink shall be located as depicted if figure 2.

7.  General-purpose sink shall have one DI water faucet and shall be of
    a gooseneck design constructed of polypro and shall be fitted with a
    remote on/off valve located on the front of the station.

8.  Station shall have two duplex electrical receptacles, GFI protected,
    110-120 VAC, 60Hz, installed on hood front with fume tight covers.

9.  Station shall have one Teflon DI water hand spray that is
    retractable and shall be installed in the middle front portion of
    the work deck as depicted if figure 2.

10. The station shall have a dry well 12L x 6W x 12D inches +/- ½ inch
    in length, width and depth for the storage of waste chemicals and
    shall be fitted with a flush fitting cover.

11. The dry well shall be located as depicted if figure 2.

12. The dry well shall have a drain to the hood tub.

13. The station shall have three tube clean troughs each trough 6L x 20W
    x 10D inches +/- ½ inch in length, width and depth and shall be of
    polypro construction with removable covers designed as follows:

    a.  The first trough shall be a DI water rinse tank with a drain to
        the hood tub and shall have an adjustable DI water flow inlet
        that drains to the hood tub.

    b.  The second trough shall be for use with unheated HF and nitric
        acid and shall drain to a polypro carboy in the base cabinet.
        The carboy shall be at least of five-gallon capacity and shall
        include a fill port, drain spigot and carrying handle. Carboy
        shall be monitored for a full condition and shall activate
        audible and visual alarms alerting users that the carboy is
        full. The trough shall have a three way drain selector switch to
        allow for draining to carboy or selection of city drain for wash
        down and cleaning. The selector switch shall be interlocked with
        carboy to prevent selection of carboy if carboy is full.

    c.  The third trough shall be a final DI water rinse tank with a
        drain to the hood tub and shall have an adjustable DI water flow
        inlet that drains to the hood tub.

14. The three tube trough shall be located as depicted if figure 2.

15. The station shall have a variable laminar flow and exhaust volume
    system to control laminar flow exhaust volume from 90 lfm with the
    sash open, with a near linear reduction to 50 lfm with the sash
    closed.

16. The variable laminar flow and exhaust volume system shall provide an
    analog signal for output to (NASA supplied) external exhaust fan
    speed controller to maintain a negative pressure within the work
    zone.

## Options

Price separately as options to wet station number 2 the following
equipment.

1.  A Teflon DI water spray wand that is retractable and shall be
    installed left side of the work deck. The spray wand should be 18-20
    inches in length and have a spray pattern at the tip of at least 160
    degrees. The spray wand shall be located as depicted if figure 2.

2.  A Teflon DI water hand spray that is retractable and shall be
    installed in the middle front portion of the work deck as depicted
    if figure 1. that shall be connected to the hot DI water system
    (NASA responsible for making this connection). This option would be
    dependent upon the purchase of option 2 for station 1.

# Clean hood (Figure 3)

## General

The clean hood shall be designed to provide a laminar down flow class
100 clean work environment within the hood enclosure. HEPA filter units
shall be located at the top of the workstation to minimize width of
workstation. The hoods overall dimensions shall be 74L x 38W x 129H
inches +/- 1 inch in length, width and height.

## Materials Description

All polypropylene materials shall be free of visual and structural
defects and shall meet the requirements of ASTM D-4101-02 Group1 Class 1
Grade 11.

## Construction

1.  The basic material of construction for the HEPA filter module shall
    be 100% white, stress-relived, acid-resistant polypro.

2.  The HEPA filter module shall use at least 3/8 inch thick polypro
    material and all joints shall be thermally fused.

3.  The work surface shall be constructed of type and shall be 30 +/- ½
    inches above the floor.

4.  The hood sides and rear liners shall be 304 stainless steel 16 gauge
    and shall extend downward to the work surface.

5.  The hoods right end wall shall include cut outs for integrating with
    NASA owned dual tube furnace.

6.  The location and dimensions of cutouts shall be as defined in figure
    3 side view.

7.  The HEPA filter module shall be supported on a white enameled
    tubular steel frame.

8.  The height of the white enameled tubular steel frame shall be such
    that the hood interior working height is 96 +/- ½ inches.

9.  The HEPA filter module shall have a front mounted static pressure
    gauge, blower speed control, blower on/off switch and light on/off
    switch.

10. The HEPA filter module shall have a prefilter.

11. Both the prefilter(s) and HEPA filter(s) shall be replaceable from
    the front.

12. The HEPA filter module shall have integral fluorescent lighting with
    an egg crate grill capable of producing at least 150ft candles of
    illumination at 30 inches below the HEPA filter module.

13. The hood shall have a clear acrylic sash 7 +/- ½ inches high
    extending the full length of the hood and shall be mounted at the
    top of the hood working area opening.

Figure 1

A.  Hot plate well

B.  Two stage cascade rinse.

C.  DI water faucet.

D.  Dry sink.

E.  General-purpose sink.

F.  N2 blow off gun.

G.  DI water hand spray gun.

H.  Optional hot DI hand spray gun.

I.  Optional spinner rinser/dryer

Figure 2

A.  DI water faucet.

B.  General-purpose sink.

C.  Dry well.

D.  Tube Trough #1 DI water rinse with drain to hood tub.

E.  Tube trough #2 HF/Nitric acid etch tank with drain to polypro
    carboy.

F.  Tube trough #3 Final DI water rinse tank with drain to hood tub.

G.  N2 blow off gun.

H.  DI water hand spray gun.

I.  Optional hot DI hand spray gun.

J.  Optional DI water spray wand.

Front view Side View

Figure 3

Figure 3 shows location and size of cutouts to accommodate NASA owned
dual tube furnace, along with overall dimensions for reference.