Semiconductor Package Land Structure to Prevent MLF Land Dislodging
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Solution Overview
Problem
Micro lead frame (MLF) type semiconductor packages face reliability issues due to lands dislodging during manufacturing or attachment to a next level assembly, such as a PCB, which reduces their reliability and functionality.
Innovation Solution
A substrate structure for electronic packages is developed with a land structure and adhesion pad isolated by an insulating layer, where the land and adhesion pad have size variations, and the land structure includes a larger upper part and smaller lower part, providing improved locking features to prevent dislodging. This is achieved through a process involving half-etching, resin layer formation, and plating, with optional use of conductive wires or solder balls for connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lands are made physically isolated from adhesion pad using resin layer in MLF package, then electrical connection and functionality are improved, but lands become dislodged during manufacturing or assembly causing reliability degradation
Solution Approach 1:
The patent extends the land structure from a simple planar configuration to a three-dimensional structure by adding downward projections that extend into the resin layer. This dimensional change creates mechanical interlocking between the land and the resin, preventing dislodgement while maintaining electrical connection functionality.
Solution Approach 2:
The land structure is segmented into multiple functional portions: an upper surface for electrical connection, downward projections for mechanical anchoring, and side surfaces for structural support. This segmentation allows each portion to fulfill its specific function optimally, with projections providing attachment strength while the upper surface maintains electrical connectivity.
2Reliability
If land structure is extended with larger upper part and smaller lower part, then locking features are improved preventing dislodging, but manufacturing complexity increases due to additional etching and plating steps
Solution Approach 1:
The patent combines multiple functions into the land structure itself: electrical connection, mechanical anchoring, and structural support are all integrated into a single land element. The downward projections serve both as mechanical anchors and as part of the conductive path, eliminating the need for separate anchoring components.
Solution Approach 2:
The land structure exhibits local quality variations with different portions having different functions: the upper surface provides electrical connection area, the downward projections provide mechanical anchoring, and the side surfaces provide structural support. This localized functional differentiation allows optimization of each region for its specific purpose.
Data Source
AI summary
A semiconductor package structure includes a substrate comprising a land structure. The land structure includes a first land section having a first height in a cross-sectional view and a second land section having a second height in the cross-sectional view that is different than the first height. A mold encapsulant is disposed adjacent a lateral portion of the first land section and is disposed below a bottom portion of the second land section. A semiconductor die is attached to the substrate, and includes a first major surface, a second major surface opposing the first major surface, and an outer perimeter. The semiconductor die further includes a bonding structure disposed adjacent the first major surface, which is coupled to the second land section such that the first land section is disposed outside the perimeter of the semiconductor die A mold member encapsulates at least portions of the semiconductor die.