Semiconductor Package Pad Structure for Low-Temperature Reflow Wetting
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Solution Overview
Problem
In the reflow process for semiconductor packages at temperatures below 200°C, the collapsing height of the package is reduced, leading to increased non-wetting issues with electrical contacts.
Innovation Solution
The semiconductor device incorporates a semiconductor package with a package center pad and a thicker package edge pad that covers a side surface of the package, along with a solder ball positioned on the package center pad, to enhance the collapsing height and reduce non-wetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a reflow process is performed at a temperature of less than 200°C using paste with lower melting point, then cost is reduced and ecological requirements are met, but the collapsing height of the semiconductor package is reduced and non-wetting of electrical contacts increases
Solution Approach 1:
The patent applies local quality by making the package edge pad thicker than the package center pad. This localized structural modification increases the collapsing height specifically at the edge regions where non-wetting is most problematic, while maintaining the low reflow temperature process benefits.
Solution Approach 2:
The patent introduces a thickness dimension variation in the package edge pad, making it thicker than the center pad. This dimensional change creates additional collapsing height that ensures proper contact between the paste and electrical contacts during low-temperature reflow process.
2Ease of manufacture
If a reflow process is performed at a temperature of less than 200°C using paste with lower melting point, then cost is reduced and ecological requirements are met, but the collapsing height of the semiconductor package is reduced
Solution Approach 1:
The package edge pad is designed with greater thickness than the package center pad, creating localized structural reinforcement. This local quality enhancement specifically addresses the collapsing height issue at the package edges without requiring overall package redesign or higher reflow temperatures.
Solution Approach 2:
The patent utilizes the thickness dimension of the package pads as a design variable. By making the package edge pad thicker than the center pad, the invention creates additional collapsing height in the vertical dimension, compensating for the reduced collapse that occurs at lower reflow temperatures.
Data Source
AI summary
A semiconductor device according to embodiments includes a semiconductor package, a package pad positioned on a surface of the semiconductor package, and a solder ball positioned on the package pad. The package pad includes a package center pad positioned at the center of the semiconductor package, and a package edge pad positioned on an edge portion of the semiconductor package, the package edge pad covers a side surface extending from a surface of the semiconductor package.