Dual-CTE Epoxy Mold Compound Circuit Package Warpage Control
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Solution Overview
Problem
Existing circuit packaging methods using epoxy mold compounds face challenges in controlling dimensions, shapes, and thermal expansion, leading to warpage and design constraints in integrated circuits.
Innovation Solution
The use of a combination of two epoxy mold compounds with different Coefficients of Thermal Expansion (CTEs) is employed, where a second epoxy mold compound with a higher CTE is strategically placed adjacent to the circuit device to compensate for thermal expansion, thereby controlling warpage and bow in the package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single epoxy mold compound is used for packaging, then the packaging process is simple, but thermal expansion control is poor leading to warpage
Solution Approach 1:
The packaging structure is segmented into multiple epoxy mold compound layers, each with different CTE characteristics. The first layer (lower CTE) provides dimensional stability while the second layer (higher CTE) compensates for thermal expansion, collectively controlling warpage without requiring complex external components.
Solution Approach 2:
The patent employs a composite packaging structure using two different epoxy mold compounds with distinct CTE values. This composite approach combines materials with complementary thermal properties to achieve overall thermal expansion control, resolving the contradiction between structural simplicity and precision.
2Reliability
If epoxy mold compound packaging is used, then circuit protection is provided, but control over dimensions and shapes is difficult
Solution Approach 1:
Different regions of the packaging structure are assigned different material properties. The first epoxy layer (lower CTE) is positioned to provide overall structural stability, while the second epoxy layer (higher CTE) is strategically placed to compensate for thermal expansion in specific areas, enabling localized control over dimensional changes.
3Ease of manufacture
If thermal expansion compensation is not implemented, then manufacturing is simpler, but warpage occurs reducing reliability
Solution Approach 1:
The patent changes the material parameter (CTE) of the epoxy mold compound by using two different compounds with distinct thermal expansion characteristics. This parameter variation enables thermal expansion compensation within the packaging structure itself, maintaining reliability while keeping the manufacturing process relatively simple.
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 better control over panel bow, relieving design constraints and improving manufacturing processes by ensuring consistent thermal expansion across the package, reducing warpage and enhancing the reliability of circuit packages.
Implementation Method 1
a second epoxy mold compound with a higher CTE than the first CTE is disposed adjacent to the circuit device so as to compensate for thermal expansion
Data Source
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AI summary
A circuit package comprises a circuit device in a first epoxy mold compound and a second epoxy mold compound of different compositions.