Precision Dicing Saw

Role in QLT Fabrication

The precision dicing saw performs diamond-blade singulation of fabricated photonic chips from multi-project wafers (MPW). This is the final mechanical processing step before packaging and optical testing.

Primary Tasks

Why This Matters for Photonics

Unlike standard semiconductor dicing (where edge quality is a yield concern but not a functional parameter), photonic chip dicing directly affects device performance:

• Waveguide facet quality determines fiber-to-chip coupling loss. Chipping > 5 μm at a waveguide facet can scatter light and increase insertion loss by 1–3 dB.
• Ductile-regime dicing (fine grit, low feed rate, high RPM) of SiO₂/Si₃N₄ stacks can produce optical-quality facets with Sa < 1.5 nm roughness, potentially eliminating post-dice polishing (ref: University of Southampton, CLEO 2023).
• Die geometry accuracy matters for packaging alignment ● 5×5 mm die must be within ±10 μm for automated pick-and-place assembly.

Process Flow

DICING PROCESS FLOW:

1. Mount wafer/die on dicing tape (UV-release, Nitto/Lintec)
├── Tape on dicing frame (6" or 8" ring frame)
└── Ensure no bubbles under substrate

2. Load frame onto saw chuck (vacuum hold)

3. Align to scribe lanes / alignment marks
├── Theta alignment (correct for wafer rotation)
├── Street detection (pattern recognition or manual)
└── Set index (die pitch, 5.0 mm or 10.0 mm)

4. Set cutting parameters
├── Blade: DISCO NBC-ZH or ZH05, 30 μm kerf
├── Spindle speed: 30,000–40,000 RPM
├── Feed rate: 10–30 mm/s (ductile regime for SiN/SiO₂)
├── Cut depth: through-cut (525 μm Si + tape partial)
└── Coolant: DI water, 1.5–2.0 L/min per nozzle

5. Execute X-direction cuts → rotate 90° → Y-direction cuts

6. Post-dice inspection
├── Kerf width check (target: 30 ± 3 μm)
├── Chipping inspection (optical microscope, < 5 μm)
└── Die dimension verification

7. UV-expand tape → pick individual die

TOTAL TIME PER WAFER: 30–60 min (depends on die count + inspection)

Recommended Configuration

The DISCO DAD3350 is the industry-standard automatic dicing saw for 8" wafers, with the largest installed base in semiconductor and photonics fabs worldwide. It offers the precision, automation, and process control needed for photonic chip singulation.

Process Integration

Wafer Preparation

• Remove wafer from storage (N₂ cabinet or cleanroom desiccator)
• Visual inspection under microscope ● confirm no pre-existing cracks
• Mount wafer face-up on UV-release dicing tape stretched over ring frame
• Press to remove air bubbles; ensure full adhesion across wafer back
• Load frame into dicing saw chuck

Alignment

• Initialize saw; load recipe (QLT_SiN_5x5mm or QLT_SiN_10x10mm)
• Move to first alignment mark (top-left of wafer)
• Auto-align or manually register theta correction
• Set index pitch: X = 5.000 mm, Y = 5.000 mm (or 10.000 mm)
• Verify street positions across 3+ points on wafer
• Set blade height (NCS auto-detect or manual touch-off)
• Set cut depth: wafer thickness (525 μm) + 20 μm tape penetration = 545 μm total

Cutting

• Start DI water flow (1.5–2.0 L/min per nozzle)
• Execute X-direction cuts (all parallel streets)
• Rotate chuck 90° (theta)
• Execute Y-direction cuts
• For step-cut: repeat sequence with fine blade and reduced feed rate

Post-Dice

• Rinse wafer on chuck with DI spray (remove debris)
• Spin-dry or N₂ blow-dry
• Transfer frame to inspection station
• Inspect kerf width, chipping, die dimensions under optical microscope
• UV-expose tape (for UV-release adhesive) ● 30 s under UV lamp
• Pick individual die with vacuum tweezers or automated pick tool
• Store die in gel-pack trays or waffle packs

Vendor Options & Pricing

New System Cost

Prices are estimates from university procurement records, NSF equipment proposals, and industry sources. DISCO and ADT do not publish pricing ● all require direct RFQ.

Used/Refurbished Market

Used market note: DISCO DAD3350 has the largest used inventory of any dicing saw (57+ units listed on CAE Online alone, vintages 2001–2019). This creates strong buyer leverage.

Where to Buy

Outsource Dicing Services (Alternative to Equipment Purchase)

For prototype phase (< 20 wafers), outsourcing dicing is the most cost-effective approach:

Recommendation: Start by outsourcing 5–10 wafers to SemiDice or GDSI while procuring the saw. This gets die in hand for packaging development with zero capital outlay.

Cost History & Market Dynamics

USED DICING SAW PRICE TREND (DISCO DAD3350):

2018-2019:  $10-25k (abundant supply; 200mm fabs decommissioning)
2020-2021:  $15-30k (moderate tightening; COVID disruptions)
2022-2023:  $20-40k (semiconductor boom; used equipment demand surge)
2024-2025:  $15-35k (market normalizing; newer DAD3351 entering used market)
2025-2026:  $12-30k (estimated; DAD3350 aging; good buyer's market)

TREND: DAD3350 used prices are DECLINING as fabs upgrade to DAD3351/3361
and larger-wafer DFD6361 dual-spindle systems. This is EXCELLENT timing
for QLT to acquire a refurbished DAD3350 at a favorable price.

SUPPLY DRIVERS:
├── 200mm fab retooling → steady supply of used 8" saws
├── OSAT (packaging) consolidation → equipment liquidations
├── University lab upgrades → good-condition refurbs entering market
└── DAD3350 has the DEEPEST used pool of any dicing saw model

Facility Requirements

Floor Space

Electrical

DI Water Supply

Compressed Air (for Air-Bearing Models ● ADT, Loadpoint)

Note: DISCO DAD3350 uses ball-bearing spindle ● no compressed air needed for spindle. CDA still needed for pneumatic actuators (~50 L/min).

Drain / Waste Water

Vibration

Sound / Noise

Lighting / Cleanroom

Exhaust

Safety & Handling

Hazards

PPE Requirements

Training