Conductive Pad Anchor Flange for Low-Profile Semiconductor Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor packages face issues with uneven surfaces and copper exposure due to the use of lead frames, leading to soldering problems and poor insulation coverage.
Innovation Solution
A semiconductor package is manufactured without a lead frame, featuring a conductive pad with a perpendicular side surface and an anchor flange, encapsulated in a molding compound, with the chip and conductive pad exposed from the bottom, allowing for improved soldering and reduced package height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lead frame is used to manufacture the die pad and finished leads, then the semiconductor package can be assembled, but the uneven surface of the lead frame results in soldering problems and poor insulation coverage
Solution Approach 1:
The patent removes the lead frame from the packaging structure entirely, extracting the problematic component that caused surface unevenness. The die pad and leads are now formed as integrated structures without the lead frame substrate, eliminating the source of the soldering and insulation problems while maintaining the essential electrical connection functions.
2Ease of manufacture
If the insulation layer coverage on the finished leads is insufficient, then the manufacturing process is simpler, but copper exposure problems occur
Solution Approach 1:
The patent employs a multi-layer composite structure consisting of the conductive pad, insulation layer, and molding compound. This composite design ensures that the insulation layer is properly integrated with the conductive elements, providing complete copper coverage while maintaining manufacturing feasibility. The layered composite structure naturally addresses the copper exposure issue through proper material stacking and integration.
3Productivity
If conventional QFN packaging process is used, then the package can be manufactured, but the package height cannot be minimized further
Solution Approach 1:
The patent reconfigures the packaging architecture by integrating the die pad and leads into a more compact three-dimensional arrangement. The conductive pad structure with its specific geometric configuration allows for reduced vertical spacing, minimizing the overall package height while preserving all necessary electrical connection pathways and mechanical support functions.
4Device complexity
If the conductive pad does not have an anchor flange, then the manufacturing process is simpler, but the conductive pad may separate from the molding compound
Solution Approach 1:
The anchor flange is formed as an integral part of the conductive pad structure during the manufacturing process, creating a pre-built mechanical interlocking feature. This preliminary formation of the flange structure ensures that when the molding compound is applied, immediate mechanical engagement occurs, preventing separation without requiring additional manufacturing steps or complex assembly 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 eliminates soldering issues and copper exposure, achieving a lower package height and enhanced interlock between the conductive pad and molding compound, preventing separation and improving electrical connectivity.
Implementation Method 1
an anchor flange formed around a top surface of the conductive pad to engage the molding compound
Implementation Method 2
a chip encapsulated in the molding compound and having a bottom on which a solder layer is formed
Data Source
AI summary
A semiconductor package includes a molding compound, a chip and a conductive pad, wherein the chip is electrically connected to the conductive pad and both are encapsulated in the molding compound. An anchor flange is formed around a top surface of the conductive pad by over plating. When the conductive pad is embedded in the molding compound, the anchor flange engages the molding compound to prevent the conductive pad from separation. Bottoms of a chip and the conductive pad are exposed from the molding compound for electrically soldering to a circuit board.