Bumpless Die-Package Interface for Low-Height BBUL Packages
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Solution Overview
Problem
Conventional semiconductor packages face challenges in achieving compact, high-performance designs with low warpage and increased circuit density, particularly in the integration of semiconductor dies with bumpless interfaces for Build-Up Layer (BBUL) packages, which require innovative solutions to eliminate copper bumps and optimize die-package interactions.
Innovation Solution
The implementation of a bumpless die-package interface in semiconductor packages involves embedding a semiconductor die within a substrate with conductive vias and conductive lines, where the conductive lines are directly coupled to the substrate's vias, and the use of self-aligned via fabrication and photo-sensitive dielectric layers to eliminate copper bumps and reduce the number of die layers, enabling a coreless substrate with reduced package height and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor packages use copper bumps to attach silicon die to processor package wires, then reliable electrical connection is achieved, but package height increases and manufacturing complexity increases
Solution Approach 1:
The patent removes copper bumps from the package structure entirely, replacing them with a bumpless build-up layer (BBUL) technique where conductive vias are formed directly through the substrate to contact the die, eliminating the need for separate bump components and reducing package height
Solution Approach 2:
The substrate and interconnection structure are merged into a single integrated component where the build-up layer contains both mechanical support and electrical interconnection functions, eliminating the need for separate bump components and reducing overall package complexity
2Strength
If conventional substrates include thick resin core layer, then mechanical strength is improved, but package height increases and cost increases
Solution Approach 1:
The patent extracts and removes the thick resin core layer from the substrate structure, retaining only the essential thin substrate and build-up layer components needed for electrical interconnection, thereby reducing package height while maintaining necessary mechanical strength through optimized substrate design
Solution Approach 2:
The substrate thickness and material composition parameters are changed from conventional thick resin core to thin substrate with controlled dielectric layers, optimizing the balance between mechanical strength and package height reduction
3Quantity of substance
If more copper bumps are used to support larger circuit density, then electrical connection capability is improved, but manufacturing complexity increases and cost increases
Solution Approach 1:
The patent merges the electrical interconnection function into the substrate's build-up layer, where multiple conductive vias and traces are integrated directly into the substrate structure, allowing high circuit density without adding external bump components and reducing manufacturing complexity
Solution Approach 2:
The patent transitions from vertical bump-based interconnection to planar multi-layer trace and via structures within the substrate, enabling high circuit density through lateral routing and multiple conductive layers rather than vertical stacking of bumps
Data Source
AI summary
A packaged semiconductor die with a bumpless die-package interface and methods of fabrication are described. For example, a semiconductor package includes a substrate having a land side with a lowermost layer of conductive vias. A semiconductor die is embedded in the substrate and has an uppermost layer of conductive lines, one of which is coupled directly to a conductive via of the lowermost layer of conductive vias of the substrate. In another example, a semiconductor package includes a substrate having a land side with a lowermost layer of conductive vias. A semiconductor die is embedded in the substrate and has an uppermost layer of conductive lines with a layer of conductive vias disposed thereon. At least one of the conductive lines is coupled directly to a conductive via of the semiconductor die which is coupled directly to a conductive via of the lowermost layer of conductive vias of the substrate.