Thermosonic Flip Chip Bonding for Thin Semiconductor Packages
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving reduced thickness and simplified connections between semiconductor dies and leads, which limits the signal carrying ability and increases package volume.
Innovation Solution
The method involves forming bond pads on a substrate, etching recesses to create leads, and applying a finish plating layer on the leads, which are then thermosonically bonded to the die and encapsulated in an insulative material, reducing the overall package height and improving mechanical and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional die pad and wire bonding methods are used, then mechanical connection and electrical coupling are achieved, but package thickness increases and signal carrying ability decreases
Solution Approach 1:
The patent removes the traditional die pad component entirely, mounting the semiconductor die directly onto the leads. This extraction of the die pad eliminates the thickness contribution from this intermediate layer while maintaining mechanical support and electrical connection functions through the direct die-to-lead mounting structure.
Solution Approach 2:
The patent merges the mechanical support function and electrical connection function into a single integrated structure where the leads directly support the die and provide electrical pathways. This consolidation eliminates the need for separate die pad and wire bond components, reducing overall package thickness while maintaining signal carrying capability.
2Volume of stationary object
If traditional connection methods with die pad and wires are used, then electrical connection is established, but package volume increases
Solution Approach 1:
The patent extracts and removes the die pad component from the package structure, eliminating the volume occupied by this intermediate layer. The direct mounting of die to leads reduces the overall package volume while simplifying the connection structure.
Solution Approach 2:
The patent combines multiple functions (mechanical support, electrical connection, and structural framework) into the integrated lead structure, eliminating the need for separate die pad and wire bond components. This merging reduces both package volume and connection structure complexity.
3Reliability
If thicker package structure is used, then mechanical strength is maintained, but signal transmission capability is reduced
Solution Approach 1:
By removing the die pad, the patent shortens the electrical signal path from the die to the external leads, reducing package thickness while improving signal transmission capability through the more direct and controlled impedance pathway provided by the lead structure.
Solution Approach 2:
The integration of mechanical support and electrical connection functions into the lead structure creates optimized signal pathways with controlled impedance, improving signal transmission capability while reducing package thickness compared to traditional separate support and connection structures.
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 results in a thinner package with enhanced signal transmission capabilities, allowing for higher data transfer rates and the use of more readily available and cost-effective encapsulants, while maintaining strong mechanical connections between the die and leads.
Implementation Method 1
thermosonically bonding the leads to a die by thermosonically bonding the finish plating to the die
Data Source
AI summary
A method of making a package is disclosed. The method may include forming bond pads on a first surface of a substrate, forming leads in the substrate by etching recesses in a second surface of the substrate, the second surface being opposite the first surface, and plating at least a portion of a top surface of the leads with a layer of finish plating. The method may also include thermosonically bonding the leads to a die by thermosonically bonding the finish plating to the die and encapsulating the die and the leads in an encapsulant.