Package Structure Warpage Control via Dummy Die and Cover
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Solution Overview
Problem
The semiconductor industry faces challenges in bonding integrated circuit chips directly onto substrates due to increased integration density and thermal expansion mismatch, leading to warpage and cold joints in package structures.
Innovation Solution
Incorporating dummy die structures in scribe line regions and using cover structures to reduce warpage, with the option to omit encapsulant, and employing thicker top dies in die stacks for support and protection, thereby controlling the encapsulant ratio and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If integrated circuit chips are bonded directly onto substrates, then manufacturing process is simplified, but warpage and cold joints occur due to thermal expansion mismatch
Solution Approach 1:
The patent introduces an interposer as an intermediary component between the integrated circuit chip and the substrate. This interposer has a different coefficient of thermal expansion that serves as a buffer, reducing the thermal expansion mismatch between the chip and substrate. The interposer redistributes ball contacts from the chip to a larger area, thereby reducing warpage and preventing cold joints while maintaining the direct bonding approach.
2Productivity
If integration density is increased by reducing minimum feature size, then more components are integrated into a given area, but bonding capability is exceeded
Solution Approach 1:
The patent transitions from a two-dimensional bonding approach to a three-dimensional package structure by introducing vertical stacking with interposers. The interposer provides additional layers and redistribution of connection points, effectively moving the bonding challenge from a 2D surface area constraint to a 3D volume solution, allowing higher integration density without exceeding bonding capabilities.
3Adaptability or versatility
If interposers are used to redistribute ball contact areas, then bonding capability is extended, but device complexity increases
Solution Approach 1:
The interposer is designed to perform multiple functions simultaneously: it redistributes ball contacts to a larger area, provides thermal expansion buffering, enables three-dimensional packaging, and supports multiple chips. By consolidating these functions into a single component, the patent reduces overall package structure complexity compared to using separate elements for each function.
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 enhances the reliability of package structures by minimizing warpage and thermal expansion-related stress, potentially eliminating the need for encapsulant and improving yield.
Implementation Method 1
dummy die structures adjacent the active dies to reduce the warpage of the package structure
Implementation Method 2
employing thicker top dies in die stacks for support and protection
Data Source
AI summary
An embodiment is a method including: attaching a first die to a first side of a first component using first electrical connectors, attaching a first side of a second die to first side of the first component using second electrical connectors, attaching a dummy die to the first side of the first component in a scribe line region of the first component, adhering a cover structure to a second side of the second die, and singulating the first component and the dummy die to form a package structure.