Warp-Resistant Layer in Semiconductor Package Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor package structures experience warpage due to mismatched thermal expansion coefficients between substrates and packaging encapsulants, leading to defects such as poor wire bonding, crack formation, and unsatisfactory solder ball attachment during high-temperature fabrication processes.
Innovation Solution
A warp-resistant layer is formed on the packaging encapsulant using selected materials like chromium, silicon dioxide, or organic compounds with specific thicknesses, reducing the variation in warpage of the semiconductor package structure between 25° C. and 260° C. to less than 560 μm, thereby enhancing structural strength and mitigating thermal stress effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a substrate and packaging encapsulant are used in a semiconductor package structure, then the package structure can be fabricated with standard materials, but the mismatch in coefficient of thermal expansion causes warpage during high-temperature processing
Solution Approach 1:
The patent applies local quality by introducing a warp-resistant layer with specific material properties (different CTE) at a specific location (between substrate and encapsulant) to locally counteract the thermal expansion mismatch. This layer has tailored mechanical and thermal properties that differ from both the substrate and encapsulant, creating a localized compensation mechanism that maintains overall structural stability during temperature variations.
Solution Approach 2:
The patent employs composite materials by combining the substrate, warp-resistant layer, and packaging encapsulant into a multi-layer composite structure. The warp-resistant layer is made from specific materials (such as tungsten, molybdenum, or their alloys) that form a composite system with tailored overall CTE, balancing the thermal expansion characteristics of the constituent materials to minimize warpage while maintaining manufacturability.
2Length of moving object
If the thickness of the semiconductor package structure is reduced to meet miniaturization demands, then the package size decreases, but the warpage phenomenon becomes more observable and problematic
Solution Approach 1:
The patent applies local quality by introducing a warp-resistant layer with specific material properties (different CTE) at a specific location (between substrate and encapsulant) to locally counteract the thermal expansion mismatch. This layer has tailored mechanical and thermal properties that differ from both the substrate and encapsulant, creating a localized compensation mechanism that maintains overall structural stability during temperature variations.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the thickness, material composition, and thermal expansion coefficient of the warp-resistant layer to optimize its warpage compensation effect. The layer's parameters are specifically designed to balance the thermal stresses in the miniaturized package structure, ensuring adequate warpage resistance even as overall package dimensions are reduced.
3Device complexity
If no warp-resistant layer is used, then the fabrication process is simpler, but defects such as poor wire bonding, crack formation, and unsatisfactory solder ball attachment occur
Solution Approach 1:
The patent applies preliminary action by incorporating the warp-resistant layer into the package structure before performing critical fabrication steps such as wire bonding, bump bonding, and solder ball attachment. This pre-established structural foundation prevents warpage-induced defects during subsequent high-temperature processing and assembly operations, ensuring reliable product formation without requiring complex post-processing corrections.
Solution Approach 2:
The patent employs composite materials by combining the substrate, warp-resistant layer, and packaging encapsulant into a multi-layer composite structure. The warp-resistant layer is made from specific materials (such as tungsten, molybdenum, or their alloys) that form a composite system with tailored overall CTE, balancing the thermal expansion characteristics of the constituent materials to minimize warpage while maintaining manufacturability.
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
The implementation of a warp-resistant layer significantly reduces warpage in semiconductor package structures, minimizing defects and improving the reliability of internal wire bonding and solder ball attachment, thus enhancing the overall yield and performance of semiconductor packages.
Implementation Method 1
due to the mismatch in coefficient of thermal expansion (CTE) between a substrate and a packaging encapsulant, the substrate and the packaging encapsulant are subject to different degrees of thermal expansion resulting in stress effects, causing a warpage phenomenon
Data Source
AI summary
A semiconductor package structure and a fabrication method thereof are provided. The fabrication method comprises: providing a substrate strip, the substrate strip comprising a plurality of substrate units which comprise a substrate unit; disposing a plurality of chips on the plurality of substrate units; disposing a packaging encapsulant on the substrate strip to encapsulate the chips; forming a warp-resistant layer on a top surface of the packaging encapsulant; and dividing the substrate strip to separate the plurality of substrate units to further fabricate a plurality of semiconductor package structures which comprise a semiconductor package structure comprising the substrate unit, wherein the warp-resistant layer is formed of a selected material with a selected thickness to make a variation of warpage of the semiconductor package structure at a temperature between 25° C. and 260° C. to be smaller than 560 μm.