How a Fan-Out Chip Package Connects Multiple Chips on a Metal Substrate

This patent describes a way to stack and connect multiple tiny computer chips using a metal base, allowing more connections to spread out from the chip.

What it covers

Claim 1 describes a 'package-on-package device' that uses a 'metal substrate' with distinct 'outer conductive pads' and 'inner conductive pads'. A 'microelectronic device' connects to the 'inner conductive pads' via 'first interconnects', which can be 'posts' (Claim 4). 'Wire bond wires' attach to the 'outer conductive pads'. A 'redistribution layer' on the lower surface connects these pads. The key feature is that the 'outer conductive pads are located outside of a perimeter of the microelectronic device for the fan-out from the inner conductive pads located below the microelectronic device' (Claim 1). This allows connections to spread out beyond the chip's footprint. For example, a processor chip could be connected to memory chips stacked above it, with all connections efficiently routed to a larger circuit board below.

What it doesn't cover

• —Does not cover chip packages that do not use a metal substrate as the base (Claim 1).
• —Does not cover single-chip packages; it specifically claims a 'package-on-package device' (Claim 1).
• —Does not cover packaging where electrical connections do not 'fan-out' beyond the microelectronic device's perimeter (Claim 1).
• —Does not cover packages that connect chips without using both 'wire bond wires' and 'first interconnects' (posts) as described (Claim 1, 4).
• —Does not cover packages without a 'redistribution layer' connecting the pads on the lower surface (Claim 1).

The clever bit

The novelty lies in combining a metal substrate with electrically isolated inner and outer conductive pads, specifically designed for a 'package-on-package' configuration. This setup allows for efficient 'fan-out' of connections from both wire bonds and stacked chips, maximizing connectivity in a minimal footprint.

Why it matters

This technology is crucial for making smaller, more powerful electronic devices. By enabling the stacking of multiple chips (like a processor and memory) in a 'package-on-package' arrangement, it saves valuable space inside devices. The 'fan-out' capability allows for more electrical connections in a compact area, which is essential for high-performance chips in modern smartphones, wearables, and other miniaturized electronics.

Real-world examples

• 1.Smartphones
• 2.Wearable electronics
• 3.Internet of Things (IoT) devices
• 4.High-density memory modules
• 5.Automotive electronics control units