Redistribution Package Recess Structure for Terminal Crack Resistance
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Solution Overview
Problem
Cracks occur in the connection terminals of semiconductor packages due to thermal expansion coefficient mismatches between the semiconductor chip and the main board, affecting reliability.
Innovation Solution
A semiconductor package design featuring a front redistribution structure with recesses and dams to accommodate larger connection bumps, supported by underfill, which enhances stress distribution and prevents overflow, thereby improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor package structure is used, then manufacturing is simpler, but cracks occur in connection terminals due to thermal expansion mismatch
Solution Approach 1:
The patent applies local quality by creating a recess structure at specific locations where connection bumps are positioned. The recesses provide localized stress relief zones exactly where thermal expansion mismatch causes cracking, while the rest of the package structure remains conventional. This targeted approach improves crack resistance without unnecessarily complicating the entire package design.
Solution Approach 2:
The recesses are formed in advance during manufacturing to anticipate and prevent crack formation. By pre-configuring the recess structures that accommodate connection bumps, the design provides beforehand cushioning against the thermal stress that will occur during operation, preventing cracks before they can develop.
2Reliability
If connection bumps are enlarged to increase contact area, then stress distribution improves, but underfill may overflow during manufacturing
Solution Approach 1:
The recesses create localized containment zones for the underfill material. By confining the underfill to specific recess areas rather than allowing it to spread freely across the entire surface, the design maintains manufacturing precision while still achieving the stress distribution benefits of larger connection bumps.
Solution Approach 2:
The patent segments the underfill application area into discrete recess zones. This segmentation prevents underfill overflow by dividing the continuous surface into separate, bounded compartments, each capable of accommodating a connection bump and its associated underfill without interfering with adjacent structures.
3Reliability
If recesses are added to accommodate larger bumps, then stress management improves, but manufacturing complexity increases
Solution Approach 1:
The recesses are formed as part of the preliminary substrate preparation before mounting the semiconductor die and applying underfill. By completing the recess formation early in the manufacturing process, the design integrates the stress management feature into the base structure without requiring additional complex steps later in production.
Data Source
AI summary
A semiconductor package including: a front redistribution structure including an insulating layer defining an upper surface, a lower surface opposing the upper surface, and a side surface, front redistribution layers including a first redistribution layer on a first level adjacent to the lower surface and second redistribution layers on a second level higher than the first level relative to the lower surface, the second redistribution layers having an inner redistribution layer and an outer redistribution layer, a recess exposing at least a portion of the outer redistribution layer, and a dam on at least one side of the recess; connection bumps including a first bump electrically connected to the first redistribution layer and a second bump electrically connected to the outer redistribution layer within the recess; and an underfill that extends along a side surface of the second bump and a side surface of the dam within the recess.