Mold Metal Layer Passives for Multi-Die Signal Integrity
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Solution Overview
Problem
On-die inductors required for high-speed serial IO and RF circuitry occupy valuable die area and face challenges due to parasitic capacitance, impedance discontinuities, and strict isolation requirements, limiting their performance and necessitating expensive packaging solutions.
Innovation Solution
Implementing passive electrical components like inductors, capacitors, and transformers within mold metal layers in a multi-die complex, which allows for improved signal integrity, power delivery, and reduced parasitic capacitance, freeing up on-die area and enhancing isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If on-die inductors are designed within thick outer metal layers, then impedance discontinuities are compensated, but valuable die area is occupied and parasitic capacitance limits performance
Solution Approach 1:
The patent moves passive electrical components from the traditional on-die location to the mold package substrate, utilizing the third dimension (vertical stacking) to relocate components. This allows inductors to be formed in metal layers of the mold package rather than consuming valuable on-die real estate, while still providing the necessary impedance compensation for high-speed serial IO interfaces.
2Reliability
If on-die inductors are used to control parasitic capacitance, then signal performance is improved, but strict isolation requirements increase device complexity
Solution Approach 1:
The patent extracts passive electrical components from the active die and places them in the mold package substrate. This physical separation automatically provides the required isolation between active circuitry and passive components, eliminating the need for complex isolation structures and design constraints on the die itself.
3Area of stationary object
If mold metal layers are used for passive components, then on-die area is freed and parasitic capacitance is reduced, but additional packaging complexity is introduced
Solution Approach 1:
The patent makes the mold package substrate multi-functional by having it serve both as the structural packaging housing and as the substrate for forming passive electrical components. The metal layers in the mold package are utilized for dual purposes: providing mechanical support/protection and functioning as inductor/capacitor traces, thereby eliminating the need for separate passive component packages.
Data Source
AI summary
In one embodiment, a multi-die complex includes a mold material, first and second integrated circuit dies within the mold material, and one or more metal layers within the mold material. One or more passive electrical components, e.g., an inductor, a capacitor, or RF shielding, are formed at least partially within the metal layers.