Inter-Die Via Bonded Assembly With Dielectric Bonding
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Solution Overview
Problem
Current semiconductor bonding technologies face challenges in achieving reliable and efficient inter-die via structures for three-dimensional memory devices, particularly in reducing the need for high-temperature metal-to-metal bonding which degrades device performance and reliability.
Innovation Solution
A bonded assembly is created using dielectric-to-dielectric bonding between two semiconductor dies, with conductive via structures extending through the substrates and dielectric layers, and redistribution metal interconnect structures on the backside surface to electrically connect these via structures, eliminating the need for metal-to-metal bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal-to-metal bonding is used to achieve inter-die via structures, then electrical connection between dies is established, but thermal stress increases and device reliability degrades
Solution Approach 1:
The patent introduces dielectric material as an intermediary substance between metal interconnect structures of different dies. Conductive vias filled with conductive material are formed through dielectric layers, allowing electrical connection without direct metal-to-metal contact. This intermediary dielectric approach reduces thermal stress while maintaining electrical connectivity between stacked dies.
Solution Approach 2:
The patent replaces the mechanical/thermal bonding process of metal-to-metal bonding with a dielectric-based bonding approach. Instead of relying on high-temperature metal bonding, the invention uses dielectric-to-dielectric bonding with subsequently formed conductive vias, substituting the bonding mechanism to eliminate thermal stress issues.
2Strength
If high-temperature bonding processes are used to form inter-die via structures, then bonding strength is achieved, but device performance degrades
Solution Approach 1:
The patent changes the bonding temperature parameter from high-temperature metal-to-metal bonding to low-temperature dielectric-to-dielectric bonding. The dielectric layers are bonded at temperatures that preserve device performance, while bonding strength is achieved through the dielectric bonding process itself rather than high-temperature metal bonding.
Solution Approach 2:
The patent substitutes high-temperature thermal bonding with low-temperature dielectric bonding. The bonding mechanism changes from thermal diffusion bonding of metals to dielectric layer adhesion, eliminating the need for high temperatures that would degrade device performance.
3Reliability
If dielectric-to-dielectric bonding is used to bond semiconductor dies, then bonding yield and reliability are enhanced, but additional processing steps are required
Solution Approach 1:
The patent segments the inter-die connection process into distinct stages: first bonding dielectric layers together, then subsequently forming conductive vias through the bonded dielectric structure. This segmentation allows the bonding process to be separated from the via formation process, enabling low-temperature dielectric bonding followed by via fabrication.
Solution Approach 2:
The patent performs dielectric-to-dielectric bonding as a preliminary action before forming the conductive via structures. By bonding the dielectric layers first, the foundation for subsequent via formation is established, allowing the more complex via fabrication steps to occur after the bonding is complete.
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 enhances bonding yield and reliability by using dielectric-to-dielectric bonding, reducing thermal stress and improving the performance of three-dimensional memory devices.
Implementation Method 1
bonding the second semiconductor die to the first semiconductor die employing dielectric-to-dielectric bonding such that the first dielectric material layers face the second dielectric material layers
Data Source
AI summary
A bonded assembly includes a first semiconductor die and a second semiconductor die that are bonded to each other by dielectric-to-dielectric bonding. First conductive via structures vertically extend through the second semiconductor die and a respective subset of the first dielectric material layers in the first semiconductor die, and contact a respective first metal interconnect structure in the first semiconductor die. Second conductive via structures vertically extend through a second substrate and a respective subset of the second dielectric material layers in the second semiconductor die, and contacting a respective second metal interconnect structure in the second semiconductor die. Redistribution metal interconnect structures located over a backside surface of the second substrate electrically connect the first conductive via structures and the second conductive via structures, and provide electrical interconnection between the first semiconductor die and the second semiconductor die.