Waferpedia

SCREEN

WS 820 L

EtchSCREEN WS 820 L family
Research Quality: 50% complete

The SCREEN / DNS WS 820 L is a wet station for 8-inch wafers used for SiN wet etching and nitride strip processes. The WS 820 L uses chemicals including H3PO4, IPA, and HF.[1]

WS 820 L — Inventory photo
Fig. 01WS 820 LInventory photo[1]

Power

3 Phase, 208V, 170a, 100V[1]

Vacuum

H 3 PO 4 DIW Spiking Pump[1]

Gas delivery

H3PO4 , IPA , HF[1]

What it is

The SCREEN WS 820 L is a wet station for semiconductor wafer processing.[3]

The WS 820 L is a SCREEN / DNS model used with 8-inch wafers.[3][4][1][2]

How it works

General reference — not yet source-verified

A wet station processes wafers by moving them through liquid chemical and rinse steps in enclosed handling equipment.

A wet station commonly uses tanks, pumps, heaters, filters, transfer handling, and dry-off functions to control surface treatment and post-process cleaning.

Where it fits in the process flow

General reference — not yet source-verified

A wet station sits in the fabrication flow where wafers need chemical etching, stripping, cleaning, rinsing, or drying before the next process step.

A wet station often follows patterning or deposition-related steps and supports downstream inspection, further processing, or final rinse and dry preparation.

Applications

The WS 820 L is used for wet etching and nitride strip processing.[1]

What do the numbers mean?

Power & electrical2

Phase
3 Phase, 208V, 170a, 100V[1]
Accurate?
Power
3 Phase, 208V, 170A, 100V[1]
Accurate?

Vacuum & pumping4

H 3 PO 4 DIW Spiking Pump[1]
Accurate?
Measuring Units
H3PO4 measuring tank, DIW measuring tank, H3PO4 DIW spiking pump, HF measuring tank[1]
Accurate?
Circulation Pump
FS 30 HT 2[1]
Accurate?
Pump
FS 30 HT 2[1]
Accurate?

Wafer handling11

Rear type transfer flow[1]
Accurate?
PLC (Loader / Unloader)
Mitsubishi A3A CPU P21[1]
Accurate?
Olifra
wafer flatzone[1]
Accurate?
Front carrier detector sensor[1]
Accurate?
2 carrier loading (stocker 8 carrier loading[1]
Accurate?
Robot:[1]
Accurate?
Wafer Size
8 inch[1]
Accurate?
Transfer Type
Rear type transfer flow[1]
Accurate?
Wafer Flatzone
Olifra[1]
Accurate?
Front Carrier Detector Sensor
Yes[1]
Accurate?
Carrier Loading
2 carrier loading (stocker 8 carrier loading)[1]
Accurate?

Gas & chemistry2

Chemical
H3PO4 , IPA , HF[1]
Accurate?
Chemicals
H3PO4, IPA, HF[1]
Accurate?

Control & software3

Main PC
Mitsubishi/LM (hard disket OK)[1]
Accurate?
PLC
Mitsubishi A3A CPU P21[1]
Accurate?
Main PC
Mitsubishi/LM[1]
Accurate?

Configuration & options19

SiN Wet Etching[1]
Accurate?
Process for Nitride Strip[1]
Accurate?
IPA dryer fire extinguisher[1]
Accurate?
Signal Tower
3 color (GYR) Patlite lamp type[1]
Accurate?
Left/ Right Stepping Motor (Oriental
VEXTA A 6259)[1]
Accurate?
Up/Down Stepping Motor (Oriental
VEXTA PK 596 H[1]
Accurate?
Measuring Unit:[1]
Accurate?
H3PO4 Measuring Tank[1]
Accurate?
DIW Measuring Tank[1]
Accurate?
HF Measuring Tank[1]
Accurate?
Process
SiN wet etching, nitride strip[1]
Accurate?
IPA Dryer Fire Extinguisher
Yes[1]
Accurate?
Stepping Motors (Left/Right)
Oriental VEXTA A 6259[1]
Accurate?
Stepping Motors (Up/Down)
Oriental VEXTA PK 596 H[1]
Accurate?
Resistivity Meter
DKK AQ 10 (Final Rinse)[1]
Accurate?
Circulation Heater
In-Line Heater[1]
Accurate?
Circulation Filter
High Temp Filter[1]
Accurate?
Aspirator Drain
Yes[1]
Accurate?
Filter
High Temp Filter[1]
Accurate?

Vintage & configurations

  1. 1996Vintage[2]

    Described as a 1996 vintage unit.

  2. 1997Vintage[1]

    Described as a 1997 vintage unit.

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What does it need to run?

Site utility requirements, footprint, and infrastructure needed to install and operate this tool. Sourced from public records.

  • ChemicalH3PO4 , IPA , HF[1]
  • Phase3 Phase, 208V, 170a, 100V[1]
  • ConfigurationH 3 PO 4 DIW Spiking Pump[1]
  • ChemicalsH3PO4, IPA, HF[1]
  • Power3 Phase, 208V, 170A, 100V[1]
  • Measuring UnitsH3PO4 measuring tank, DIW measuring tank, H3PO4 DIW spiking pump, HF measuring tank[1]
  • Circulation PumpFS 30 HT 2[1]
  • PumpFS 30 HT 2[1]

Where are the manuals?

Generated from public-source data on file. Enter your email to access — nothing is published; details are routed privately.

Not publicly documented

Field notes

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Frequently asked questions

What types of chemicals are typically used in wet etch systems?General reference — not yet source-verified

Common chemicals include hydrofluoric acid (HF) for silicon dioxide etching, phosphoric acid for silicon nitride, potassium hydroxide (KOH) or TMAH for silicon anisotropic etching, and mixtures like buffered oxide etch (BOE) for oxide removal. The choice depends on the material being etched and the required selectivity.

How does wet etching compare to dry etching in terms of profile?General reference — not yet source-verified

Wet etching is isotropic, meaning it etches equally in all directions, resulting in undercut beneath the mask. Dry etching (plasma-based) can achieve anisotropic profiles with vertical sidewalls, which is often required for high-density features. Wet etching is preferred where high selectivity or damage-free removal is more important than critical dimension control.

What factors affect etch uniformity across the wafer?General reference — not yet source-verified

Uniformity is influenced by bath temperature distribution, chemical concentration gradients, agitation method (e.g., megasonic or nitrogen bubbling), wafer positioning, and etch rate dependence on pattern density. Proper system design and process optimization are essential to achieve acceptable within-wafer and wafer-to-wafer uniformity.

Can wet etching be used for critical layers in advanced nodes?General reference — not yet source-verified

While wet etching is still used for certain non-critical layers and cleaning steps, advanced sub-micron nodes increasingly rely on dry etching for critical pattern transfer due to its anisotropic nature and better CD control. However, wet etching remains important for sacrificial layers, pre-clean, and where high etch selectivity is needed.

What maintenance considerations are unique to wet etch systems?General reference — not yet source-verified

Regular maintenance includes chemical bath monitoring and replenishment, filter replacement, cleaning of chamber components to prevent particle buildup, and inspection of seals and plumbing for corrosion. Exhaust and waste management systems require careful handling of aggressive chemicals. Safety interlocks and emergency shower/eyewash stations are mandatory.

Not publicly documented

The following facts about the WS 820 L are absent from this record as of this revision. First-hand knowledge or a citation closes a gap; every submission is reviewed before publication.

  • No publicly documented variants, configuration options, or revision breakpoints of the WS 820 L are on record.

    Answerable by: an OEM product catalog or an engineer who ordered or specified the tool

  • The control-system platform and OS era of the WS 820 L are not on record.

    Answerable by: an engineer who operated it or OEM installation records

  • No publicly documented failure modes or field errata for the WS 820 L are on record.

    Answerable by: a field service engineer, process engineer, or maintenance technician

  • The process node or technology generation of the WS 820 L is not on record.

    Answerable by: an OEM datasheet or a fab qualification report

  • No publicly documented compatible parts, consumables, or accessories for the WS 820 L are on record.

    Answerable by: an OEM parts catalog or a service engineer

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Sources & citations

Sources (4)Every fact above is drawn from these public sources
  1. [1]Equipment inventory listing
  2. [2]Equipment inventory listing
  3. [3]Equipment inventory listing
  4. [4]Equipment inventory listing
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Last updated Oct 4, 2026.

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