A CT scanner reveals surprises inside the 386 processor's ceramic package
12 hours ago
- Intel 386 was the first 32-bit x86 chip, housed in a ceramic PG.A. with 132 gold-plated pins.
- A CT scan revealed six layers of complex internal wiring, two tiers of gold contacts, and virtually invisible wires for electroplating.
- The package used custom single-row double shelf bonding for improved power and noise performance.
- The chip has separate power and ground networks for I/O and logic to prevent noise interference.
- Manufacturing involved ceramic green sheets, tungsten wiring, sintering at 1500-1600°C, and gold plating.
- The ceramic package was expensive, leading to a later low-cost plastic PQFP version.
- CT scanning helped determine the pin-to-pad mapping, previously unavailable outside Intel.
- Intel's early packaging evolved from 16-pin limits to PGAs and modern high-density BGA and LGA packages.