Universal Surface-Mount Semiconductor Package Coplanarity
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving low profile heights, maintaining coplanarity of leads and die pads, and reducing manufacturing costs, particularly due to the need for package-specific equipment and mold cavity tools, which limits flexibility and increases production costs.
Innovation Solution
The development of a universal surface mount package (USMP) process that uses a dual-sided etched leadframe, shared block molding, and laser-based plastic and lead definition to produce a wide variety of packages, including footed and leadless types, without the need for specialized equipment, enabling flexible manufacturing and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If package-specific mold cavity tools and equipment are used, then manufacturing precision and reliability are improved, but device complexity and production costs increase
Solution Approach 1:
The patent applies a universal mold cavity tool that can manufacture multiple package types (leaded and leadless) without requiring package-specific tools. The same equipment and tooling are used across different package configurations, eliminating the need for specialized equipment while maintaining manufacturing precision through consistent process control.
2Manufacturing precision
If package-specific mold cavity tools are used, then manufacturing precision is improved, but productivity decreases due to limited flexibility
Solution Approach 1:
The universal mold cavity tool enables a single production line to manufacture multiple package types including both leaded and leadless packages. This eliminates the need for separate production lines for different package types, significantly improving productivity and flexibility while maintaining manufacturing precision through consistent process control.
Solution Approach 2:
The patent merges the manufacturing processes for different package types into a single universal process. By combining the capabilities to produce both leaded and leadless packages in one facility using the same equipment, the system achieves both high precision and operational flexibility.
3Ease of manufacture
If conventional leaded packages with bent leads are used, then ease of manufacture is improved, but manufacturing precision deteriorates due to lead bending variability
Solution Approach 1:
The patent extracts the problematic lead bending step from the manufacturing process by producing leadless packages where the leads remain straight and coplanar with the die pad. This eliminates the source of coplanarity variability while maintaining ease of manufacture through a simplified process that requires no mechanical forming operations.
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 allows for the production of a diverse range of semiconductor packages in a single factory, reducing production costs and increasing flexibility, while ensuring coplanarity and compatibility with both wave-solder and reflow assembly methods, thus overcoming the limitations of existing technologies.
Implementation Method 1
a first laser beam is used to remove the plastic that connects the individual packages... a second laser beam is used to remove the metal conductors that typically connect adjacent packages
Data Source
AI summary
A variety of footed and leadless semiconductor packages, with either exposed or isolated die pads, are described. Some of the packages have leads with highly coplanar feet that protrude from a plastic body, facilitating mounting the packages on printed circuit boards using wave-soldering techniques.