TSV 3D Packaging Self-Alignment Plasma Bonding
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Solution Overview
Problem
Current 3D semiconductor packaging technologies, such as wire bonding and flip chip technologies, face limitations in precision alignment, production efficiency, electrical conductivity, and signal delay, particularly in high-density and high-speed applications, and often require complex processes and carrier wafers.
Innovation Solution
A through silicon via (TSV) method that self-aligns substrates at low temperatures using plasma bonding and electroplating, eliminating the need for carrier wafers, and forming high-conductivity connections between semiconductor dies with a seed layer and electroplating layer, enhancing precision alignment and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire bonding technology is used to connect semiconductor devices, then manufacturing cost is reduced, but parasitic inductance increases due to longer signal lines, limiting ultrahigh speed signal processing
Solution Approach 1:
The patent transitions from planar wire bonding to three-dimensional vertical interconnection through TSV structures. By stacking semiconductor dies vertically and connecting them through silicon via holes filled with conductive material, the signal path is shortened in the horizontal dimension while utilizing the vertical dimension for inter-layer connections, thereby reducing parasitic inductance while maintaining manufacturing feasibility
Solution Approach 2:
The TSV structure embeds conductive filling material within silicon via holes that penetrate through the substrate thickness. This nested configuration allows electrical connections to be made through the bulk of the substrate rather than along the surface, effectively reducing the signal path length and associated parasitic inductance while keeping the connection points compact
2Reliability
If flip chip technology with solder is used, then electrical connection is achieved, but production cost increases due to complicated processes including solder flux application, alignment, reflow, and underfill filling
Solution Approach 1:
The patent extracts and eliminates the soldering process entirely from the semiconductor packaging workflow. By using TSV structures with direct conductive filling (such as copper electroplating) through the substrate, the complex solder flux application, reflow, and underfill processes are removed, significantly simplifying manufacturing while maintaining reliable electrical connections
Solution Approach 2:
The patent replaces the thermal-mechanical soldering process with a direct electroplating or electroless plating process. Instead of using heat and pressure to melt solder and form joints, the conductive material is deposited directly into the TSV holes through electrochemical reactions, eliminating the need for flux, reflow ovens, and complex alignment systems
3Device complexity
If ACA flip chip technology is used, then the number of processes is reduced, but process time increases due to film application and temporary bonding steps
Solution Approach 1:
The conductive material is pre-deposited into the TSV holes before the semiconductor dies are stacked and bonded. This preliminary electroplating action ensures that the via holes are already filled with conductive material ready for immediate electrical connection, eliminating the need for subsequent film application and temporary bonding steps that characterize ACA technology
4Ease of operation
If conventional alignment methods are used, then substrates can be aligned, but alignment precision is insufficient for submicron-level requirements in high-density packaging
Solution Approach 1:
The patent implements self-alignment mechanisms where the TSV structures themselves serve as alignment references. By designing the via holes and overlying conductive patterns with precise geometric relationships, the stacking process automatically aligns successive dies through mechanical interlocking or optical registration features built into the TSV structure, achieving submicron precision without complex external alignment equipment
5Temperature
If carrier wafers are used in the fabrication process, then substrate support is provided, but process complexity increases and productivity decreases
Solution Approach 1:
The patent extracts and eliminates the carrier wafer from the fabrication process. By designing the TSV structures and bonding process to work with free-standing substrates or directly bonded configurations, the intermediate carrier wafer step is removed, simplifying the process flow and improving productivity by eliminating the additional handling and removal steps associated with carrier wafers
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 method achieves high precision alignment, improved production efficiency, and minimized electrical signal delay while simplifying processes and eliminating the need for carrier wafers, resulting in high-quality, high-conductivity connections between semiconductor dies.
Implementation Method 1
self-aligns substrates at low temperatures using plasma bonding
Implementation Method 2
forming an electroplating layer on a top portion of the seed layer by using electroplating, including the inside of the via hole
Data Source
AI summary
The present invention relates to a through silicon via (TSV) for 3D packaging to integrate a semiconductor device and a method for manufacturing the same, and more particularly, to a through silicon via (TSV) for 3D packaging of a semiconductor device that is capable of improving production efficiency, having very high electric conductivity, and minimizing electrical signal delay, without using a carrier wafer by self-aligning substrates in a low temperature state and sequentially bonding a plurality of semiconductor dies (or semiconductor chips), and a method of manufacturing the same.