Die Stack Bonding Structure for Low-Temperature 3D Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional die bonding processes for three-dimensional integrated semiconductor devices require extremely clean and planar contact surfaces, costly plasma treatment, and high-temperature annealing, which can lead to die damage due to thermal and mechanical stress.
Innovation Solution
A bonding structure comprising a bonding dielectric structure, a bonding interconnect structure, and a bonding dummy pattern, where the bonding dielectric structure is formed using a low dielectric constant polymer, and the bonding interconnect structure is made of a metal alloy, with the bonding dummy pattern being electrically conductive and floated, allowing for lower temperature bonding and reduced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional die bonding processes use high-temperature annealing to achieve strong bonding, then bonding strength is improved, but thermal stress damages the die
Solution Approach 1:
The patent changes the bonding temperature parameter from conventional high-temperature annealing (typically above 400°C) to low-temperature bonding (below 200°C). This is achieved through modified bonding processes that enable strong adhesion without requiring extreme temperatures, thereby reducing thermal stress and preventing die damage while maintaining bonding strength
Solution Approach 2:
The patent employs composite bonding structures that combine multiple materials with complementary properties. These composite structures enable strong bonding at lower temperatures by distributing thermal stress across different material layers with matched thermal expansion coefficients, reducing the harmful thermal stress on individual dies
2Manufacturing precision
If conventional die bonding processes use plasma treatment to clean contact surfaces, then surface cleanliness is improved, but processing cost increases
Solution Approach 1:
The patent extracts and eliminates the plasma treatment step from the conventional bonding process. Instead of using expensive plasma cleaning, the invention achieves adequate surface cleanliness through alternative methods such as chemical-mechanical polishing (CMP) or optimized surface preparation techniques that are less costly and equally effective for the bonding application
Solution Approach 2:
The patent replaces expensive plasma treatment with cheaper, single-use surface preparation methods. The bonding process uses disposable or consumable materials such as bonding polymers or adhesives that pre-clean or protect the bonding surfaces, eliminating the need for repeated expensive plasma cleaning cycles
3Manufacturing precision
If conventional die bonding processes require extremely clean and planar contact surfaces, then bonding quality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the surface quality parameters by relaxing the requirements for extreme planarity and cleanliness. The modified bonding process accepts surfaces with greater tolerances in roughness and flatness, eliminating the need for complex CMP and extensive cleaning steps while maintaining adequate bonding quality through adjusted bonding conditions
Solution Approach 2:
The patent introduces intermediary bonding layers or adhesives between the die surfaces. These intermediary materials compensate for surface imperfections, allowing bonding of surfaces that would otherwise be considered too rough or non-planar. The bonding polymer or adhesive acts as a mediator that fills gaps and conforms to surface variations, reducing the need for extremely precise surface preparation
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 solution enables improved bonding strength and reduced thermal stress between dies, eliminating the need for high-temperature annealing and costly plasma treatment, while maintaining adequate electrical interconnection.
Implementation Method 1
a bonding dielectric structure (BDS) that bonds the first die and the second die
Implementation Method 2
a bonding interconnect structure (BIS) that electrically connects the first die and the second die
Data Source
AI summary
A die stack includes: a first die including a first semiconductor substrate; a second die including a second semiconductor substrate; a bonding dielectric structure including a bonding polymer and that bonds the first die and the second die; a bonding interconnect structure that extends through the bonding dielectric structure to bond and electrically connect the first die and the second die; and a bonding dummy pattern that extends through the bonding dielectric structure to bond the first die and the second die. The bonding dummy pattern is electrically conductive and is electrically floated.