L6 · 3D teardown

1-in-1 I-type NPC three-level SiC module

One three-level phase leg: a laminated busbar with bent legs onto the dies, copper clips linking T1 to T4, clamp diodes to the neutral point.

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Original 1-in-1 I-type NPC three-level SiC module, exploded: baseplate, AMB substrate, six die groups, copper clips, bond wires, P / NP / N laminated busbar with films, AC terminal, press-fit pins, housing and lid.

Selected part T1 / T4 outer switches

Switch with PWM, connecting X1 to P and X2 to N.

The image keeps the default explosion; the 2D layer diagram follows separation and selection

Exploded separation100%

AssembledExploded

Separation changes display spacing only. It does not simulate switching, current or manufacturing tolerance.

Keyboard controls

Arrow keys orbit, plus and minus zoom, Home resets the view. Tab moves between parts and topology nodes; Enter or Space selects. Arrow keys adjust separation.

2D layer schematic

Selected part: T1 / T4 outer switches

Full module: baseplate, housing and lid. P / NP / N terminals sit at the left end, AC at the right; press-fit signal pins pass through the lid.

Preparing the 3D view. Part details, the topology and the separation control are available.

Original generic model · 1-in-1 I-type NPC · no switching animation

Selected part

T1 / T4 outer switches外管

Role: Switch with PWM, connecting X1 to P and X2 to N.
Features: Two parallel SiC MOSFET dies per switch. The T1 sources reach the X1 island through copper clips; the T4 sources are pressed directly by bent legs of the N layer. Gate and Kelvin source each have a wire to a narrow substrate trace.
Common materials: silicon carbide die, aluminium-based top metallization, nickel-silver backside

One I-type NPC phase leg

Select a device or terminal to locate it in the module. Arrows show each device’s conducting direction.

Selected partT1 / T4 outer switches

T1 / T4 are the outer switches and do the PWM switching. When T1 turns off, current freewheels through D5–T2, so commutation happens only between T1 and D5 (the short loop through the P–NP capacitor). That is why T1 sits next to D5 and the P and NP layers are stacked together; T4, D6, NP and N mirror it.

Main power path
Neutral clamp

Solid: the T1–T4 series path; dashed: the neutral-clamp branches through D5 / D6. In steady state each device blocks half the DC-link voltage.

Static schematic. All part details remain below; enable JavaScript for linked selection and separation.All parts

T1 / T4 outer switches

Role: Switch with PWM, connecting X1 to P and X2 to N.
Features: Two parallel SiC MOSFET dies per switch. The T1 sources reach the X1 island through copper clips; the T4 sources are pressed directly by bent legs of the N layer. Gate and Kelvin source each have a wire to a narrow substrate trace.
Common materials: silicon carbide die, aluminium-based top metallization, nickel-silver backside

T2 / T3 inner switches

Role: Stay on for half the output period, connecting the AC output to X1 or X2.
Features: Again two parallel SiC MOSFET dies. T2 sits on the X1 island with source clips landing on the AC island; T3 sits on the AC island with source clips landing on X2.
Common materials: silicon carbide die, aluminium-based top metallization, nickel-silver backside

D5 / D6 clamp diodes

Role: Clamp the inner nodes X1 and X2 to the neutral point and freewheel after an outer switch turns off.
Features: D5 has its cathode on X1 and its anodes pressed directly by NP-layer legs; D6 has its cathode on the NP island and anode clips to X2. SiC Schottky dies have almost no reverse-recovery charge.
Common materials: silicon carbide Schottky diode die

P busbar layer

Role: DC+, connecting the external P terminal to the island under T1.
Features: Top layer of the stack. Its left end rises and folds over the lid into a bolt terminal. One bent leg drops through openings in the two layers below onto the P island.
Common materials: copper sheet, nickel- or tin-plated

NP busbar layer

Role: Neutral point, connecting the D5 anodes and the NP island under D6.
Features: Sits between P and N. Bent legs press straight onto the D5 anodes and one more lands on the NP island; both short commutation loops pass through this layer.
Common materials: copper sheet, nickel- or tin-plated

N busbar layer

Role: DC−, connecting directly to the T4 sources.
Features: Bottom layer of the stack. Its bent legs press down on the T4 source pads, leaving room beside each foot for the gate and Kelvin wires.
Common materials: copper sheet, nickel- or tin-plated

Interlayer films

Role: Separate the P, NP and N layers while keeping them close enough for low stray inductance.
Features: Three films: one under N and one between each pair of layers. Each film overhangs the copper slightly and is opened where a leg passes through. Real busbars usually insulate the top face too; it is left off here to show the P layer.
Common materials: polyimide or polyethylene naphthalate film

AC terminal

Role: Bring the AC island out to the output bolt terminal at the right end.
Features: One formed copper strap: a wide foot on the AC island, a rise, a level run to the right end, then up through the lid and folded into a terminal. It stays out of the laminate.
Common materials: copper sheet, nickel-plated

Copper clips

Role: Connect a die’s top source or anode to the next island instead of rows of heavy aluminium wire.
Features: One clip per die, bent into foot, riser, bridge, riser and foot. Four groups: T1 to X1, T2 to AC, T3 to X2 and D6 to X2.
Common materials: oxygen-free copper, nickel- or silver-plated, sintered or soldered

Gate and Kelvin wires

Role: Connect each MOSFET’s gate and Kelvin source to narrow substrate traces.
Features: Two wires per die; the gate wire jumps the Kelvin trace to the outer gate trace. The Kelvin source is taken apart from the power source, so the power-loop voltage drop stays out of the gate loop.
Common materials: aluminium or copper-clad aluminium wire

Press-fit pins

Role: Bring the four gates, Kelvin sources and the NTC out to the driver board.
Features: Ten pins stand on the ends of the substrate traces and pass through collared holes in the lid. The needle-eye tips press into the driver board without solder.
Common materials: tin-plated copper alloy

NTC thermistor

Role: Sense substrate temperature for the driver’s over-temperature protection.
Features: One chip resistor bridges two small pads, each with its own pin. It reads substrate temperature, not die junction temperature.
Common materials: metal-oxide ceramic

AMB substrate

Role: Insulate the dies electrically from the baseplate while conducting their heat down.
Features: Copper brazed to both faces of the ceramic. The top copper forms five power islands, P, X1, AC, X2 and NP, plus gate and Kelvin traces; X1 and X2 are U-shaped so the traces can pass through.
Common materials: silicon nitride ceramic, active-metal-brazed copper

Solder and sinter layers

Role: Fix the dies to the islands and the substrate to the baseplate.
Features: A thin sintered-silver layer under each die and a solder layer under the substrate. Both sit in the heat path.
Common materials: sintered silver, tin-silver-copper solder

Baseplate

Role: Carry the substrate and mount to the heatsink through four corner holes.
Features: Drawn as a flat 130 × 67 mm plate, without pre-bow or pin fins.
Common materials: nickel-plated copper or aluminium silicon carbide

Housing frame

Role: Enclose the substrate and busbar; the thicker ends carry the mounting holes.
Features: A real module is filled with silicone gel, omitted here. The housing-off and die-level views hide it.
Common materials: glass-filled polyphenylene sulfide or polybutylene terephthalate

Lid

Role: Close the top, locate the signal pins and support the terminals.
Features: Ten collared pin holes and four slots let the P, NP, N and AC terminals pass through and fold over the lid.
Common materials: glass-filled polyphenylene sulfide or polybutylene terephthalate