Semiconductor Pad Structure for Stronger Solder Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The strength of solder connections in semiconductor devices is low due to the reduction in size of semiconductor chips and the increase in signal lines, which results in smaller pads and consequently weaker solder connections.
Innovation Solution
A semiconductor device with a pad having a concave portion, where a diffusion layer and a melting layer are disposed. The diffusion layer remains on the pad surface while diffusing into the solder, and the melting layer melts and diffuses into the solder, enhancing the solder connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the pad size is reduced to accommodate smaller semiconductor chips and increased signal lines, then the chip size and signal line density are improved, but the solder connection strength becomes lower
Solution Approach 1:
The pad is divided into multiple functional layers: a base pad layer, a diffusion layer containing metal particles that diffuse into solder, and a melting layer that melts during soldering. This segmentation allows each layer to perform its specific function, maintaining connection strength despite reduced overall pad size
Solution Approach 2:
Different regions of the pad structure are given different properties: the diffusion layer contains metal particles with specific diffusion characteristics, while the melting layer has controlled melting properties. This local differentiation enables optimized solder interaction at each level, preserving connection strength in miniaturized pads
2Area of moving object
If the pad size is reduced, then the semiconductor chip size is decreased, but the solder connection portion becomes smaller and weaker
Solution Approach 1:
The pad structure uses composite material design with multiple metal layers having different properties. The diffusion layer contains metal particles that form alloy compounds with solder, while the melting layer provides controlled melting behavior. This composite structure enhances connection reliability in miniaturized chips
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 described solution significantly improves the strength of solder connections, even on smaller pads, by maintaining a diffusion layer between the pad and the solder and ensuring uniform contact with the melting layer.
Implementation Method 1
a diffusion layer disposed at the concave portion and constituted with a metal which remains on the surface of the pad while diffusing into solder upon the solder connection
Implementation Method 2
a melting layer disposed adjacent to the diffusion layer and constituted with a metal which diffuses and melts into the solder upon the solder connection
Data Source
AI summary
A semiconductor device includes a pad, a diffusion layer, and a melting layer. The pad included by the semiconductor device includes a concave portion on a surface at which solder connection is to be performed. The diffusion layer included by the semiconductor device is disposed at the concave portion and constituted with a metal which remains on the surface of the pad while diffusing into solder upon the solder connection. The melting layer included by the semiconductor device is disposed adjacent to the diffusion layer and constituted with a metal which diffuses and melts into the solder upon the solder connection.