Stacked Semiconductor Package With Oxide Bonding for Low-Height Reliability
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Solution Overview
Problem
Existing semiconductor packages face challenges in reducing size and improving reliability while minimizing defects and fabrication defects.
Innovation Solution
A semiconductor package design featuring stacked semiconductor dies with a stepwise shape, connected by wires and covered by a mold layer, utilizing oxide bonding between dies and polymer layers with enhanced elasticity and plasticity to prevent cracks and adhesion issues, and omitting adhesion films to reduce height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesion films are used between package substrate and semiconductor dies, then adhesion reliability is improved, but package height increases
Solution Approach 1:
The patent removes the adhesion film layer from the package structure, extracting the problematic component that caused height increase while maintaining adhesion reliability through direct bonding between the package substrate and semiconductor dies
Solution Approach 2:
The patent employs asymmetric thickness design where the polymer layer has a first thickness and the adhesion film has a second thickness different from the first, allowing optimized adhesion performance without uniform height increase across all layers
2Ease of manufacture
If conventional bonding methods are used between semiconductor dies, then fabrication is simple, but defects and cracks occur during stacking
Solution Approach 1:
The patent changes the bonding parameters by performing thermocompression bonding at controlled temperature and pressure conditions, transforming the bonding process to achieve reliable die-to-die connections without introducing defects or cracks
Solution Approach 2:
The patent uses a composite structure involving polymer layers with hydroxyl groups on the semiconductor dies that bond through oxygen atom interactions, creating a reliable interface that prevents cracking while maintaining ease of manufacture
3Volume of stationary object
If semiconductor dies are stacked closely without spacing, then package size is reduced, but particle migration causes adhesion issues
Solution Approach 1:
The patent introduces oxygen atoms as intermediary bonding sites between the polymer layers of adjacent semiconductor dies, enabling reliable adhesion in closely stacked configurations without particle migration issues by providing controlled bonding interfaces
Solution Approach 2:
The patent applies local quality enhancement by forming hydroxyl groups specifically at the bonding interfaces of the polymer layers, creating localized high-adhesion regions that prevent particle migration while maintaining compact package size
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
The design achieves a smaller package size with enhanced reliability and reduced defects, improving fabrication yield by using oxide bonding and polymer layers with superior elasticity to manage particle migration.
Implementation Method 1
forming a hydroxyl group on the polymer layer of the first semiconductor die
Implementation Method 2
performing a thermocompression process to bond the second semiconductor die onto the first semiconductor die
Implementation Method 3
A plurality of oxygen atoms may be between the semiconductor dies
Data Source
AI summary
Disclosed are semiconductor packages and their fabrication methods. The semiconductor package comprises a package substrate, a plurality of semiconductor dies stacked on the package substrate wherein end portions of the semiconductor dies form a stepwise shape, a plurality of wires that connect the semiconductor dies to the package substrate, and a mold layer that covers the package substrate, the semiconductor dies, and the wires. Each of the semiconductor dies includes a die substrate, a die dielectric layer on the die substrate, a bonding pad on the die dielectric layer, and a first polymer layer that covers the die dielectric layer and exposes the bonding pad. A plurality of oxygen atoms are between the semiconductor dies.