Photolithography Basics: What Equipment Does a Stepper Line Need?

Photolithography represents the most capital-intensive process area in semiconductor manufacturing, with individual tools often exceeding $10 million when purchased new. For fabs expanding capacity, entering new markets, or replacing end-of-life equipment, the used equipment market offers compelling alternatives—if you know what to look for. This guide covers the complete photolithography equipment set for a functional stepper line.

The Photolithography Process Flow

Before diving into equipment, understand the process sequence:

1. Wafer priming/adhesion promotion (HMDS vapor prime)
2. Photoresist coating (spin-coat at 1,000-6,000 RPM)
3. Soft bake (90-150°C to remove solvent)
4. Exposure (stepper or scanner imaging)
5. Post-exposure bake (PEB for chemically amplified resists)
6. Development (TMAH-based developer solution)
7. Hard bake (120-180°C for resist stabilization)
8. Inspection (pattern verification and CD measurement)

Each step requires specialized equipment, though some platforms combine multiple processes.

Coater/Developer Systems

The coater/developer (track) handles resist coating, baking, and developing operations. These systems must maintain Class 1 cleanliness and precise environmental control.

TEL ACT Series (Tokyo Electron)

TEL ACT 12

• Wafer size: 300mm
• Throughput: 200+ wafers/hour
• Processes: i-line, KrF, ArF compatible
• Used market price (2026): $800,000 - $1,500,000

TEL ACT 8

• Wafer size: 200mm
• Throughput: 180+ wafers/hour
• Processes: i-line, KrF compatible
• Used market price (2026): $250,000 - $450,000

The ACT series dominates the 200mm and 300mm coater/developer market. When evaluating used units, verify:

• Environmental chamber integrity (humidity control critical)
• Hot plate uniformity (±0.3°C required)
• Pump maintenance status (vacuum chuck systems)
• Chemical delivery system compatibility with your resist chemistries

SVG (Silicon Valley Group) / ASML Track Systems

SVG 8626 / ASML 850C

• Wafer size: 200mm
• Throughput: 150+ wafers/hour
• Processes: i-line, KrF
• Used market price (2026): $180,000 - $320,000

SVG tracks, now supported by ASML, remain viable for 200mm i-line and KrF production. Spare parts availability is good through ASML's legacy support program.

When to Buy Used vs. New

Buy used when:

• Running mature processes (≥65nm nodes)
• i-line or KrF lithography (older chemistries well-supported)
• 200mm wafer size (limited new equipment availability)
• Budget constraints require capital efficiency

Buy new when:

• Developing leading-edge processes (<28nm)
• ArF immersion lithography required
• Stringent particle specifications (<0.1 defects/cm²)
• Process development requires maximum flexibility

Stepper Systems

Steppers project reticle patterns onto wafers using reduction optics (typically 4:1 or 5:1). For used equipment buyers, i-line steppers offer the best value proposition.

i-Line Steppers (365 nm)

ASML PAS 5500/60, /70, /80 Series

• Resolution: 350-500 nm (production), down to 280 nm with enhancement
• Overlay: 40-60 nm (3σ)
• Throughput: 80-120 wafers/hour (200mm)
• Used market price (2026): $150,000 - $400,000

The PAS 5500 series is the workhorse of i-line lithography. The /80 and newer models offer the best overlay performance. Key evaluation criteria:

• Lens condition (check for degradation, clouding)
• Stage positioning accuracy (laser interferometer calibration)
• Reticle handling system integrity
• Illumination uniformity across field

Canon FPA-3000i4 / i5

• Resolution: 350-450 nm
• Overlay: 50-70 nm (3σ)
• Throughput: 90-110 wafers/hour (200mm)
• Used market price (2026): $120,000 - $300,000

Canon steppers offer reliable performance for less critical layers. The i4 and i5 models represent the mature generation with good spare parts availability.

Nikon NSR-S205C / S305C

• Resolution: 350-450 nm
• Overlay: 40-60 nm (3σ)
• Throughput: 100-130 wafers/hour (200mm)
• Used market price (2026): $140,000 - $350,000

Nikon i-line steppers compete directly with ASML and Canon. The S-series offers excellent stage speed and throughput.

DUV Steppers (KrF 248 nm)

ASML PAS 5500/300 Series

• Resolution: 180-250 nm
• Overlay: 25-40 nm (3σ)
• Throughput: 100-140 wafers/hour (200mm)
• Used market price (2026): $400,000 - $800,000

KrF steppers enable sub-250nm patterning for power devices, MEMS, and analog applications. The PAS 5500/300 series remains in demand for 200mm fabs.

Scanner Systems

Scanners use scanning exposure (reticle and wafer move synchronously) to achieve larger field sizes and better resolution than steppers.

DUV Scanners (KrF and ArF)

ASML PAS 5500/500 Series (KrF)

• Resolution: 130-180 nm
• Overlay: 20-30 nm (3σ)
• Throughput: 120-160 wafers/hour (200mm)
• Used market price (2026): $600,000 - $1,200,000

ASML XT Series (ArF)

• Resolution: 65-90 nm
• Overlay: 10-15 nm (3σ)
• Throughput: 140-200 wafers/hour (300mm)
• Used market price (2026): $2,000,000 - $5,000,000

ArF scanners command premium prices even on the used market due to limited supply and continued demand for 65-90nm production.

Nikon NSR-S206D / S306C

• Resolution: 90-180 nm (KrF)
• Overlay: 20-35 nm (3σ)
• Throughput: 120-150 wafers/hour (200mm)
• Used market price (2026): $500,000 - $900,000

Nikon scanners offer competitive performance, particularly for KrF applications. Spare parts and service support remain available through Nikon Precision.

Alignment and Metrology Systems

Accurate overlay requires sophisticated alignment systems integrated with steppers/scanners. Standalone metrology tools verify performance.

Overlay Metrology

KLA Archer Series

• Measurement: Overlay error, CD measurement
• Throughput: 50-100 wafers/hour
• Used market price (2026): $200,000 - $450,000

Archer tools provide the feedback loop for lithography process control. Essential for any production line running tight overlay specifications.

Nanometrics / KLA SpectraSpan

• Measurement: Film thickness, CD, overlay
• Used market price (2026): $150,000 - $300,000

Critical Dimension (CD) Measurement

KLA eCD Series

• Measurement: SEM-based CD measurement
• Resolution: <5 nm
• Used market price (2026): $400,000 - $800,000

CD-SEMs verify that printed features match design targets. Required for process development and production monitoring.

Inspection Tools

Defect inspection catches lithography errors before they compound through subsequent process steps.

Patterned Wafer Inspection

KLA 29xx Series (Surfscan)

• Defect sensitivity: Down to 30 nm (depending on model)
• Throughput: 50-150 wafers/hour
• Used market price (2026): $300,000 - $700,000

Surfscan tools detect particles, pattern defects, and process anomalies. The 29xx series (2910, 2920, 2950) offers varying sensitivity levels.

ADE / KLA Candela Series

• Technology: Optical surface inspection
• Applications: Unpatterned wafer inspection, tool qualification
• Used market price (2026): $180,000 - $350,000

Candela systems excel at unpatterned wafer inspection—useful for incoming wafer QC and tool health monitoring.

Macro Defect Inspection

KLA Orbotech / Camtek Eagle

• Applications: Post-develop inspection, macro defect detection
• Throughput: High (200+ wafers/hour)
• Used market price (2026): $80,000 - $200,000

Macro inspection catches gross defects (missing patterns, large particles) quickly and economically.

Ancillary Equipment

Hot Plates and Chill Plates

Standalone baking units for process development or backup:

• Yield Engineering Systems (YES): $30,000 - $80,000 used
• Tokyo Electron PI-8: $40,000 - $100,000 used

Vapor Prime Systems

HMDS priming for adhesion promotion:

• YES-3: $25,000 - $60,000 used
• TEL VP-8: $35,000 - $80,000 used

Reticle Handling

Reticle stockers and inspectors:

• Nikon / ASML reticle libraries: $50,000 - $150,000 used
• KLA-Tencor reticle inspection: $300,000 - $600,000 used

Complete Line Budget Estimate (200mm i-line)

For a functional 200mm i-line lithography line:

| Equipment | Quantity | Unit Price (Used) | Total | |-----------|----------|-------------------|-------| | Coater/Developer (TEL ACT8) | 2 | $350,000 | $700,000 | | i-line Stepper (ASML PAS 5500/80) | 2 | $300,000 | $600,000 | | Overlay Metrology (KLA Archer) | 1 | $300,000 | $300,000 | | CD-SEM (KLA eCD) | 1 | $600,000 | $600,000 | | Defect Inspection (KLA 2910) | 1 | $400,000 | $400,000 | | Ancillary equipment | - | $200,000 | $200,000 | | Total | | | $2,800,000 |

Compare to new equipment cost: $15-25 million for equivalent capability.

FAQ

Q: Can I mix equipment from different manufacturers?

A: Yes, with proper integration. Coater/developer systems from TEL can feed steppers from ASML, Canon, or Nikon. The key integration points are: (1) wafer handling interfaces (FOUP, SMIF, or open cassette), (2) communication protocols (SECS/GEM), and (3) overlay matching between different exposure tools. A well-planned lithography cell can mix vendors effectively.

Q: What resolution can I achieve with used i-line equipment?

A: Standard i-line (365 nm) achieves 350-500 nm resolution in production. With resolution enhancement techniques (RET)—optical proximity correction (OPC), phase-shift masks (PSM), and off-axis illumination—you can push i-line to 280-350 nm for critical layers. For finer geometries, KrF (248 nm) or ArF (193 nm) equipment is required.

Q: How do I verify lens condition on a used stepper?

A: Lens evaluation requires: (1) field-by-field exposure tests to check uniformity, (2) star-pattern or resolution target prints to assess aberrations, (3) historical maintenance records for lens cleaning/replacement history, and (4) if possible, interferometric wavefront measurement. Cloudy or contaminated lenses show reduced transmission and degraded resolution. Budget $50,000-150,000 for lens refurbishment if needed.

Q: What's the typical lead time for used lithography equipment?

A: Lead times vary: (1) in-stock equipment: 4-8 weeks for decommissioning, crating, and shipping; (2) equipment requiring extraction from operating fabs: 3-6 months depending on replacement timeline; (3) equipment requiring refurbishment: 2-4 months additional. Plan 6-12 months from PO to production for major lithography purchases.

Conclusion

Building or expanding a photolithography line with used equipment requires careful planning and vendor selection. The 200mm i-line market offers excellent value for mature technologies, while 300mm and DUV equipment commands premiums reflecting continued demand. Focus your evaluation on: optical system condition, mechanical accuracy (stages, alignment), environmental system integrity, and spare parts availability.

Ready to source photolithography equipment? Contact Caladan Semi for assistance with coater/developer systems, steppers, scanners, and inspection tools. We provide fully tested equipment with installation support and warranty options.