Semiconductor Package Dummy Posts for Conductive Post Height Control
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Solution Overview
Problem
The increasing demand for high-performance semiconductor devices with fine patterns and high integration requires effective management of conductive post heights and widths to prevent defects like copper burrs during planarization processes.
Innovation Solution
The introduction of dummy posts with varying heights and widths, embedded in the insulating layer, which are not electrically connected to the redistribution structures, helps adjust the height of conductive posts during plating, reducing the occurrence of copper burrs and defects by being formed simultaneously with the conductive posts and covered by the encapsulant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conductive posts are formed with uniform height and width during plating, then the plating process is simple, but copper burrs and defects occur during planarization due to excessive post height
Solution Approach 1:
The conductive posts are segmented into two height groups: first conductive posts with height H1 and second conductive posts with height H2 (where H1 < H2). This segmentation allows differential height control during plating, enabling precise height management for different functional requirements while preventing copper burr formation during planarization.
Solution Approach 2:
Different regions of the substrate are assigned different post heights based on local requirements. The first conductive posts are formed with height H1 in regions where lower posts are sufficient, while second conductive posts with height H2 are formed in regions requiring higher posts. This local quality approach optimizes the overall structure by applying different characteristics to different locations.
2Manufacturing precision
If dummy posts are formed with varying heights, then conductive post height control is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Dummy posts are formed in advance before the final conductive posts. These dummy posts serve as height references during the plating process, allowing the plating parameters to be optimized based on pre-established height benchmarks. This preliminary action enables better height control without significantly complicating the main manufacturing process.
Solution Approach 2:
Dummy posts act as intermediary structures that mediate between the plating process and the final conductive post height requirements. By forming dummy posts with specific heights first, the plating process can use these as reference points to achieve uniform conductive post heights without requiring complex real-time control mechanisms.
3Reliability
If all conductive posts are made with the same width, then the fabrication process is simplified, but defect density increases due to inadequate height adjustment
Solution Approach 1:
The conductive posts are designed with different widths according to their local functional requirements. First conductive posts have width W1 and second conductive posts have width W2 (where W1 ≠ W2). This local differentiation allows optimization of each post's dimensions for its specific function, reducing defect density by preventing excessive height growth that leads to copper burrs.
Solution Approach 2:
The width parameter of conductive posts is varied to control their height during plating. By changing the width parameter (from W1 to W2), the plating process produces posts with different heights (H1 and H2) that are better controlled and less prone to forming copper burrs, thereby improving reliability.
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 precise control of conductive post heights and widths, reducing defects and copper burrs, thereby enhancing the reliability and efficiency of semiconductor package manufacturing.
Implementation Method 1
dummy posts with varying heights and widths, embedded in the insulating layer, which are not electrically connected to the redistribution structures, helps adjust the height of conductive posts during plating
Data Source
AI summary
A semiconductor package according to an example embodiment of the present disclosure comprises: a lower redistribution structure including an insulating layer, a connection pad disposed on an upper surface of the insulating layer, and an upper pad; a semiconductor chip mounted on the lower redistribution structure and connected to the upper pad; a conductive post disposed on the connection pad; at least one dummy post disposed on the lower redistribution structure; and an upper redistribution structure disposed on the semiconductor chip and connected to the conductive post, and a height of the at least one dummy post is smaller than a height of the conductive post.