Multi-Layer Gap-Fill Dielectrics for Die Warpage Control
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing warping and inducing undesirable stresses in integrated circuit die structures due to coefficient of thermal expansion (CTE) mismatches between integrated circuit dies and gap-fill dielectrics, which can affect the reliability and yield of the die structure.
Innovation Solution
Incorporating an inner gap-fill dielectric with a higher CTE than the outer gap-fill dielectric, matched to the CTE of the integrated circuit dies, to mitigate CTE mismatches and enhance the structural integrity and reliability of the die structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer gap-fill dielectric is used, then the manufacturing process is simple, but CTE mismatch causes warping and stress in the die structure
Solution Approach 1:
The gap-fill dielectric is divided into multiple layers with different CTE values. The first layer has a CTE matched to the integrated circuit dies, while the second layer has a different CTE. This segmentation allows each layer to handle specific stress requirements, preventing warping and maintaining die structure reliability during thermal cycling.
Solution Approach 2:
The patent uses a composite dielectric structure composed of two or more dielectric layers with different CTE properties. This composite approach combines the advantages of each material layer to achieve both mechanical stability and electrical performance, resolving the contradiction between manufacturing simplicity and structural reliability.
2Ease of manufacture
If gap-fill dielectric with low CTE is used, then manufacturing is easier, but thermal expansion mismatch induces stress and deformation
Solution Approach 1:
Different regions of the gap-fill dielectric structure have different CTE properties tailored to local requirements. The first dielectric layer adjacent to the integrated circuit dies has a CTE matched to the dies to minimize thermal stress at the interface, while the second layer provides additional mechanical support. This local optimization prevents warping and maintains manufacturing precision.
3Reliability
If CTE-matched inner gap-fill dielectric is added, then warping and stress are reduced, but device complexity increases
Solution Approach 1:
The dielectric structure is segmented into functional layers: the first layer provides CTE matching to prevent warping at the die interface, while the second layer provides additional mechanical support and stress distribution. This segmentation achieves warping resistance with a manageable level of complexity by assigning specific functions to each layer.
4Reliability
If multiple gap-fill dielectric layers are used, then CTE mismatch is managed better, but manufacturing precision requirements increase
Solution Approach 1:
The patent manages thermal expansion by changing the CTE parameter across different dielectric layers. The first layer has a CTE matched to the integrated circuit dies, while the second layer has a different CTE optimized for its function. This parameter variation allows effective thermal expansion management while maintaining achievable manufacturing precision through standard deposition techniques.
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 reduces the risk of warping and stress-induced deformation, thereby increasing the reliability and yield of the die structure by effectively managing thermal expansion differences between the dies and dielectrics.
Implementation Method 1
coefficient of thermal expansion (CTE) mismatches between integrated circuit dies and gap-fill dielectrics
Data Source
AI summary
Gap-fill dielectrics for die structures and methods of forming the same are provided. In an embodiment, a device includes: an outer gap-fill dielectric having a first coefficient of thermal expansion; a first integrated circuit die in the outer gap-fill dielectric; a second integrated circuit die in the outer gap-fill dielectric; an inner gap-fill dielectric between the first integrated circuit die and the second integrated circuit die, the inner gap-fill dielectric having a second coefficient of thermal expansion, the second coefficient of thermal expansion being greater than the first coefficient of thermal expansion; and a third integrated circuit die over the inner gap-fill dielectric, the third integrated circuit die bonded to the first integrated circuit die and to the second integrated circuit die.