Semiconductor Die Stack Bonding Pads for Reliable Vertical Interconnects
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Solution Overview
Problem
Current semiconductor die stack structures face challenges in efficiently bonding and connecting multiple dies while maintaining electrical integrity and mechanical stability, particularly in the formation of reliable bonding pads and through-electrodes for effective signal transfer and thermal management.
Innovation Solution
A method of manufacturing a semiconductor die stack structure involves preparing base and bottom dies with specific bonding pad structures and through-electrodes, followed by direct contact and bonding, and subsequent stacking of middle and top dies, utilizing hybrid bonding techniques and advanced metallurgy to ensure electrical connectivity and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct contact bonding of bonding pad structures is used to bond dies, then electrical connectivity and mechanical stability are improved, but manufacturing precision requirements increase
Solution Approach 1:
The bonding pad structures are formed on the dies before the bonding process, with predetermined patterns and dimensions. This preliminary formation ensures that when the dies are bonded in direct contact, the bonding pads are already positioned to achieve optimal electrical connectivity without requiring high-precision alignment during the bonding step itself.
Solution Approach 2:
The bonding pad structures utilize controlled material composition and geometric parameters (such as pad size, shape, and spacing) that are optimized for direct contact bonding. By adjusting these parameters, the design compensates for potential alignment variations and ensures reliable electrical connectivity across the bonded interface.
2Reliability
If through-electrodes are formed to pass through die substrates, then electrical connectivity between bonding pads is improved, but device complexity increases
Solution Approach 1:
The through-electrode structure is segmented into discrete regions corresponding to specific bonding pad connections. Each through-electrode is formed to connect specific front-side bonding pads to back-side bonding pads, creating modular electrical pathways that simplify the overall connectivity design while maintaining reliability.
3Temperature
If multiple dies are stacked in direct contact, then thermal management efficiency is improved, but manufacturing process complexity increases
Solution Approach 1:
Multiple dies are merged in direct physical contact to form a stacked configuration, eliminating thermal interface materials and reducing thermal resistance. This merging of dies creates efficient thermal pathways from the active regions through the substrate to the heat dissipation structures, improving thermal management while the standardized bonding process manages the complexity.
Solution Approach 2:
The bonding pad structures and substrate designs are created with multi-functionality, serving both electrical connectivity and thermal management functions. The same direct-contact bonding interface that provides electrical pathways also provides thermal pathways, reducing the need for separate thermal management components and simplifying the overall stacking process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the creation of robust semiconductor die stacks with enhanced electrical characteristics and improved mechanical stability, facilitating efficient signal transfer and thermal management by ensuring precise bonding and connectivity between dies.
Implementation Method 1
forming a base-bottom die stack structure in which the bottom die front-side bonding pad structure and the base die front-side bonding pad structure are directly in contact with each other by bonding the bottom die and the base die
Data Source
AI summary
A method of manufacturing a semiconductor die stack structure includes: preparing a base die including a base die substrate and a base die inter-layer dielectric layer; forming a base die front-side bonding pad structure; preparing a bottom die having a bottom die substrate and bottom die through-electrode; forming a bottom die front-side bonding pad structure in the bottom die substrate; forming a base-bottom die stack structure where the bottom die front-side bonding pad structure is directly in contact with the base die front-side; forming a base die through-electrode vertically passing through the base die substrate and electrically connected to the base die front-side bonding pad structure; forming a base die back-side bump structure electrically connected to the base die through-electrode; stacking middle dies and a top die in the base-bottom die stack structure; and forming a bottom die back-side bump structure electrically connected to the bottom die through-electrode.