Dual-Layer Support Structure for Electronic Package Warpage Control
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Solution Overview
Problem
Ultrathin electronic packages face challenges with temperature-related warpage during manufacturing processes, as thicker stiffeners provide better warpage control but increase stress on the die, leading to cracking, and existing solutions often improve warpage at either low or high temperatures but not both.
Innovation Solution
The use of two supports with different coefficients of thermal expansion and optimized geometry to mitigate temperature-related warpage, where a thin first support with high thermal expansion reduces low-temperature warpage and a second support with lower thermal expansion reduces high-temperature warpage, minimizing stress on the die and improving manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thicker stiffener is used, then warpage control is improved, but stress on the die increases leading to cracking
Solution Approach 1:
The stiffener is divided into multiple segments (first stiffener and second stiffener) positioned at different locations around the die. The first stiffener has a first thickness and the second stiffener has a second thickness different from the first, allowing different portions to provide different levels of support and stress distribution, thus controlling warpage while reducing concentrated stress on the die.
Solution Approach 2:
Different portions of the stiffener structure are given different local properties through varying thicknesses. The first stiffener and second stiffener have different thicknesses tailored to their specific positions, providing optimized local support characteristics that collectively control overall warpage while minimizing stress on the die.
2Stability of the object's composition
If a thicker stiffener is used, then warpage control is improved, but fabrication difficulty increases
Solution Approach 1:
The stiffener is divided into multiple segments (first stiffener and second stiffener) positioned at different locations around the die. The first stiffener has a first thickness and the second stiffener has a second thickness different from the first, allowing different portions to provide different levels of support and stress distribution, thus controlling warpage while reducing concentrated stress on the die.
Solution Approach 2:
Instead of using a uniformly thick stiffener throughout, the invention applies varying thicknesses only where needed - the first stiffener and second stiffener have different thicknesses optimized for their specific positions. This partial differentiation provides effective warpage control without the excessive fabrication complexity of a completely re-engineered thick stiffener structure.
3Ease of manufacture
If a single stiffener design is used, then manufacturing is simplified, but warpage is not reduced at both low and high temperatures
Solution Approach 1:
Different portions of the stiffener structure are given different local properties through varying thicknesses. The first stiffener and second stiffener have different thicknesses tailored to their specific positions, providing optimized local support characteristics that collectively control overall warpage while minimizing stress on the die.
Solution Approach 2:
The invention changes the thickness parameter of the stiffener at different locations - the first stiffener has a first thickness and the second stiffener has a second thickness. This parameter variation allows the structure to respond differently to thermal conditions at various positions, enabling warpage control at both low and high temperatures while maintaining manufacturing feasibility.
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 effectively reduces temperature-related warpage at both low and high temperatures, enhancing the manufacturability of electronic packages and reducing the risk of die cracking during testing.
Implementation Method 1
a thin first support with high thermal expansion reduces low-temperature warpage and a second support with lower thermal expansion reduces high-temperature warpage
Data Source
AI summary
An electronic package that includes a substrate; a die attached to the substrate; an underfill positioned between the die and the substrate due to capillary action; a first support adjacent to the die and attached to the substrate; and a second support mounted on the first support, wherein the second support is closer to the die than the first support, wherein first support surrounds the die and the second support surrounds the die, and wherein the second support is a different material than the first support. The die may be flip chip bonded to the substrate and the underfill may secure the die to the substrate. The first support may be attached to the substrate using an adhesive and the second support may be attached to the first support using an adhesive.