High Strength Silicon Nitride Substrate for SiC Power Module, AMB/DBC Ready

High Strength Si3N4 Substrate Applications

• Power Electronics: IGBT/ SiC Modules

  ✅Key Advantages

  1. Low warpage under copper load: planarity held to drawing after solder cycles (reflow 245–260 °C window).
  2. Dielectric withstand headroom: typical ≥15 kV/mm per IEC 60243-1 supports isolation design margins.
  3. Thermal pathway consistency: 70–90 W/m·K helps stabilize junction-to-case targets.

  ✅ Problem Solved

  An industrial-drive module program reported assembly rejects from bow/tilt in final soldering. After switching to Si₃N₄ DBC with defined flatness targets and Ra control, first-pass assembly yield rose by ~4.8% over three pilot lots, and rework time fell by ~22%. Thermal cycling (-40↔125 °C, 1000 cycles) passed without delamination under the customer’s internal protocol.

• Automotive Inverter/e-Powertrain

  ✅Key Advantages

  1. Thermal shock tolerance: Si₃N₄ resists crack propagation during on-vehicle thermal ramps.
  2. CTE compatibility with Cu: reduced stress compared with more brittle ceramics in thick-Cu builds.
  3. Finish options for bonding: Ni/Au or Ag support wire bond and solder attach in mixed processes.

  ✅ Problem Solved

  A 2-in-1 inverter platform faced die-attach voiding and intermittent bond lift. With Si₃N₄ DBC and a revised surface finish, bond pull variability narrowed by ~15%, and voiding fell below the line’s 5% threshold across three validation runs.

• High-Power LED/RF Packaging

  ✅Key Advantages

  1. Stable dielectric response: consistent substrate behavior improves RF and optical assemblies.
  2. Smooth, controlled Ra: supports paste print and wetting uniformity.
  3. Thin formats (≤0.3–0.5 mm): enable compact thermal paths in small outlines.

  ✅ Problem Solved

  An LED engine needed higher lumen maintenance at elevated drive currents. Moving to thin Si₃N₄ with tighter Ra reduced paste thickness scatter; junction temperature dropped by ~3–5 °C at the same current, improving long-run stability.

High Strength Silicon Nitride Substrate Usage Instructions

• Installation & Handling

  1. Inspect substrates for flatness, surface defects, or edge chipping before mounting; measure critical thickness or Ra values at specified datum points if required by process control.
  2. Use vacuum tweezers or soft-tipped ceramic tools when handling; avoid metal tweezers to prevent micro-cracks along the edges.
  3. For AMB/DBC parts, keep copper surface free of oxidation — unpack only before screen printing, soldering, or bonding.

• Assembly & Operation

  1. Solder/Die attach process:
  a. Follow reflow profile within agreed ramp-up rates (<3 °C/s recommended) to prevent thermal shock.
  b. Maintain uniform paste thickness or solder preform pressure to avoid voiding and uneven wetting.
  
  2. Wire bonding/Ni/Au surfaces:
  a. Clean surface with dry nitrogen or ion-free wipes; control ultrasonic energy to avoid surface dents.
  b. Aluminum or gold wires should be bonded after verifying finish thickness and hardness.
  
  3. Power cycling:
  a. Ensure even copper distribution to limit stress concentration.
  b. Substrate must be supported by a flat heat sink or fixture to minimize bending loads during operation.

• Storage & Shelf Life

  1. Store in original vacuum-sealed antistatic bags; recommended environment 15–25 °C, RH <60%.
  2. Avoid stacking heavy components directly on substrates; store horizontally in plastic or foam trays.
  3. Copper-clad or Ag/Ni-Au finished substrates should be processed within 6–12 months to minimize oxidation and bonding quality loss.

• Cleaning & Maintenance

  1. For bare Si₃N₄ surfaces: use ion-free water or ethanol-based cleaning; avoid abrasive pads to protect Ra tolerance.
  2. For Ni/Au or Ag surfaces: use lint-free cloth with filtered IPA; do not use alkaline detergents, acids, or ultrasonic cleaning unless verified on samples.
  3. Dry with nitrogen or filtered hot air (≤80 °C) to prevent watermarks or ionic contamination before soldering or bonding.

• Common Misuse & Solutions

  Issue	Cause	Recommended Action
  Warpage after solder reflow	Asymmetric copper layout, rapid cooling	Use symmetric stack-up, control cooling <4 °C/s, use fixture support
  Poor solder wetting	Oxidized copper/Ni-Au, high Ra or contamination	Micro-clean surface, adjust flux, verify finish age
  Crack or edge chipping	Metal tweezers, uneven clamping	Use soft fixtures, avoid point loads, and apply even clamp pressure
  Bond lift or delamination	Under-thickness Au/Ni, over-ultrasonic power	Check metallization report, optimize the bonding profile
  Ionic residue or dendrite growth	Improper cleaning/flux residue	Rinse and bake post-solder, verify ionic contamination level

High Strength Silicon Nitride (Si3N4) Substrate FAQ

1. Q: What is a high strength silicon nitride substrate used for in power modules?
   A: A high strength silicon nitride substrate provides an electrically insulating yet thermally conductive base for IGBT or SiC power chips, allowing copper metallization while preventing short circuits between the device and the heat sink.
2. Q: How does high strength silicon nitride substrate compare to AlN and alumina in reliability?
   A: Compared with Al₂O₃ and AlN, Si₃N₄ offers higher fracture toughness (6–7 MPa·m½) and better thermal shock resistance, making it less prone to cracking or warping during soldering and −40 to 150 °C power cycling.
3. Q: What is the dielectric strength of silicon nitride substrate?
   A: Si₃N₄ substrates achieve ≥15 kV/mm dielectric breakdown values measured per IEC 60243-1, supporting high isolation requirements in automotive inverters, high-voltage DC links, and industrial drives.
4. Q: Can high strength silicon nitride substrates be used with both AMB and DBC copper technologies?
   A: Yes. Si₃N₄ is compatible with both Active Metal Brazing (AMB) and Direct Bonded Copper (DBC). AMB is preferred for thick copper (>0.4 mm), while DBC is often used for standard copper thickness with tighter pattern precision.

5. Q: What flatness or warpage tolerance is achievable on a high strength silicon nitride substrate?
   A: For a 100 × 100 mm substrate, post-processing flatness can be controlled to ≤30–50 µm, depending on copper thickness and symmetry. Larger panels may require jig support or symmetrical Cu layout to maintain planarity.

6. Q: What are the most important drawing specifications I must provide for a custom high strength silicon nitride substrate?
   A: Key specifications include substrate size, thickness tolerance, flatness/warp limit, copper thickness and pattern (if AMB/DBC), surface roughness (Ra), metallization finish (Ni/Au, Ag), test voltage, and reference datum position.
7. Q: How does high strength silicon nitride substrate handle thermal cycling in SiC or IGBT modules?
   A: Due to low CTE mismatch with copper and high fracture toughness, Si₃N₄ substrates can endure 1000+ thermal cycles (−40 / 150 °C) without delamination, provided copper thickness and solder profiles are symmetric.

High Strength Silicon Nitride Substrate Reviews

• ⭐️⭐️⭐️⭐️
  We qualified a high strength silicon nitride AMB substrate for an industrial inverter. Flatness and Ra met the print, and bond variability tightened enough to release the line.
  -- Marco Ruiz, Packaging Engineer, VoltEdge Drives (Spain)
• ⭐️⭐️⭐️⭐️⭐️
  ADCERAX responded with drawing feedback and high strength Si₃N₄ substrate samples in our thickness range. Pricing was competitive for pilot lots and consistent on the ramp
  -- Grace Lin, Sourcing Manager, Aurora Motion Systems (USA)
• ⭐️⭐️⭐️⭐️⭐️
  On the high strength silicon nitride substrate with Ag finish, solder wetting was stable after storage. Lot-to-lot thickness variation was within our map limits.
  -- Kenji Yamamoto, Module Designer, Kenso Electronics (Japan)
• ⭐️⭐️⭐️⭐️⭐️
  Custom copper pattern and high strength Si₃N₄ substrate planarity enabled us to keep rework down during thermal cycling. We continued to volume PO after three builds.
  -- Oliver Becker, COO, Rhein Power Devices (Germany)