Conformal Lid for Stacked Silicon Package Warpage Control
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Solution Overview
Problem
Conventional chip packaging schemes face issues with out-of-plane deformation, particularly in asymmetrical die distributions, leading to solder connection failures and reliability issues, which are exacerbated by the use of dummy dies and high thermal expansion die attach films.
Innovation Solution
A chip package assembly utilizing a conformal lid that is structurally connected to the package substrate and interposer, eliminating the need for dummy dies by providing enhanced stiffness and improved heat transfer, thereby reducing warpage and delamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dummy dies are used to stiffen the package substrate, then resistance to out of plane deformation is improved, but manufacturing cost increases and thermal expansion issues worsen
Solution Approach 1:
The patent removes dummy dies from the package substrate, replacing them with a conformal lid structure that provides the necessary mechanical support without the added cost and thermal expansion problems of dummy dies
Solution Approach 2:
The conformal lid changes the structural parameters of the package by providing a continuous support surface that eliminates the need for discrete dummy dies, thereby reducing cost while maintaining or improving mechanical strength
2Strength
If dummy dies are used to stiffen the package substrate, then resistance to out of plane deformation is improved, but reliability worsens due to delamination and crack initiation
Solution Approach 1:
The patent eliminates dummy dies and their associated die attach films, removing the source of high thermal expansion coefficients that cause delamination and crack initiation
Solution Approach 2:
The conformal lid creates a composite structure with the package substrate that provides uniform mechanical support without introducing materials with mismatched thermal expansion properties
3Strength
If a conformal lid is used to improve stiffness, then resistance to warpage is improved, but device complexity increases
Solution Approach 1:
The conformal lid serves multiple functions simultaneously: it provides mechanical support to prevent warpage, acts as a thermal management component, and eliminates the need for dummy dies, thereby reducing overall device complexity despite its sophisticated geometry
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 conformal lid design enhances the chip package assembly's resistance to warpage, improves reliability, and reduces production costs by eliminating the need for dummy dies, while also enhancing heat dissipation and maintaining a lower package profile.
Implementation Method 1
improves heat transfer
Data Source
AI summary
A chip package assembly and method for fabricating the same are provided which utilize a conformal lid to improve the chip package assembly from deformation. In one example, a chip package assembly is provided that includes integrated circuit (IC) dies, a packaging substrate, and a lid. The packaging substrate has a die receiving area that is defined by the laterally outermost extents of the IC dies mounted to the packaging substrate. The lid a surface that includes a first region and a second region. The first region is disposed over the first IC die while the second region of the lid extends below the second surface the first IC die and is spaced above the packaging substrate. At least a portion of the second region of the lid is overlapped with the die receiving area.