US20250323166
2025-10-16
Electricity
H01L23/538
The patent application details an electronic package featuring an embedded multi-interconnect bridge (EMIB) and the methods for its fabrication. The package includes a first layer of organic material and a second layer over it, with a cavity formed through the second layer to expose the first layer's surface. A bridge substrate is placed within this cavity, supported by the first layer. The design enables electrical coupling between dies placed over the second layer through contacts on the bridge substrate.
The invention pertains to electronics packaging, focusing on EMIB technology that connects logic dies to memory dies like high bandwidth memory (HBM). Traditional EMIB uses silicon pieces with ultrafine structures embedded in organic substrates. As technology advances, bump pitch scaling is expected to decrease to 30 μm or lower. However, challenges arise due to thickness variation in multi-layer organic substrates, which complicates laser skiving and risks damaging underlying copper pads.
The disclosure describes systems with lithographically defined cavities for bridge substrates and their formation methods. Lithographic processes offer improved dimensional and positional tolerances by patterning cavities with the same chrome mask used for conductive features. This method reduces risks like copper punch through and allows precise control over cavity dimensions and location, potentially achieving tolerances of ±3 μm.
The EMIB structure includes a first organic layer with conductive layers formed over it. A cavity in the second layer exposes the first layer's surface, allowing insertion of a bridge substrate. The cavity has two portions with different widths, creating an overhang that aligns with conductive layers. The bridge substrate is mounted within the cavity, supported by the first layer, and may be secured with adhesive.
The bridge substrate can form features with fine line/spacing dimensions, potentially as small as 2/2 μm. It includes contact pads electrically coupled by finely spaced traces, facilitating connections between die regions with fine pitch bumps. A third layer covers the second layer and fills the cavity, embedding the bridge substrate while providing electrical connections through vias to various conductive layers.