Interchip

Interchip refers to communications and interfaces between separate integrated circuits (chips) within a system. The term encompasses the physical connectors, signaling methods, and communication protocols used to transfer data, control signals, and power from one chip to another, as opposed to within a single chip (intrachip or intra-die communication).

Technologies and approaches used for interchip communication range from simple to high-performance. At lower speeds, widely used serial and parallel interfaces such as I2C, SPI, and UART enable basic control and data transfer between chips. For higher performance, differential signaling and high-speed SERDES links such as LVDS, PCIe, USB, or custom protocols are employed. In advanced packaging, chip-to-chip connections may use flip-chip bonding, wire bonding, ball grid arrays, or interposers, and may be aided by through-silicon vias (TSVs) in 3D-stacked or heterogeneous integrations. Optical interconnects and silicon photonics are increasingly considered for very high-bandwidth interchip links in data centers and high-performance computing.

Applications of interchip communication include multi-die systems, system-in-package (SiP) configurations, graphics processors with high-bandwidth memory interfaces, embedded automotive and industrial electronics, and memory and processor modules in compact form factors. Interchip connectivity is a key enabler for heterogeneous integration, where dies with different processes or functions are combined into a single package or module.

Challenges in interchip design involve signal integrity, timing skew, impedance matching, power delivery, crosstalk, and thermal management. Solutions include differential signaling, careful impedance control, shielding, and advanced packaging techniques, as well as standardized high-speed interfaces and protocols. Looking forward, trends include 2.5D/3D stacking, TSV-based interconnects, and optical or silicon-photonic links to meet growing bandwidth and power efficiency demands.