Stacked Semiconductor Chips Warpage Management
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Solution Overview
Problem
Existing semiconductor device manufacturing techniques face challenges in maintaining reliable junctions between stacked semiconductor chips due to warpage issues, particularly when thicker chips are stacked on top of thinner ones, which can lead to breakage of microbumps and increased mechanical stress.
Innovation Solution
A semiconductor device configuration where the first semiconductor chip is made thinner than the subsequent chips, with an organic protective film and adhesive resin used to manage warpage, and microbumps and through-vias for electrical connectivity, ensuring the adhesive resin can expand without breaking the connections between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thicker semiconductor chip is stacked on top of a thinner chip, then the structural support is improved, but warpage-induced stress increases and microbump breakage occurs
Solution Approach 1:
The patent applies asymmetry by intentionally creating a thickness difference between the lowermost chip and upper chips, where the lowermost chip is made thinner than the upper chips. This asymmetric configuration allows the adhesive resin to expand into the gap without causing warpage-induced stress that would lead to microbump breakage, while still maintaining structural support through the stacked arrangement.
Solution Approach 2:
The patent implements beforehand cushioning by providing an adhesive resin layer between the lowermost thinner chip and the upper thicker chips. This adhesive resin acts as a cushioning element that absorbs and distributes the mechanical stress caused by thermal expansion and contraction, preventing stress concentration at the microbump junctions and reducing the risk of breakage.
2Reliability
If adhesive resin is provided between chips to manage warpage, then warpage-induced stress is reduced, but the device complexity increases
Solution Approach 1:
The adhesive resin layer serves multiple functions simultaneously: it bonds the stacked chips together, manages warpage by absorbing expansion stress, and fills the gap created by the thickness difference between chips. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving reliable warpage management.
3Productivity
If microbumps are used for electrical connectivity, then the connection density is improved, but susceptibility to warpage-induced breakage increases
Solution Approach 1:
The adhesive resin layer is positioned beforehand between the chips to cushion and absorb the mechanical stress generated by thermal expansion and contraction. This protective cushioning effect shields the microbumps from warpage-induced forces, allowing high connection density to be achieved without proportionally increasing the risk of microbump breakage.
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 configuration enhances the reliability of junctions between semiconductor chips by minimizing warpage-induced stress and preventing microbump breakage, allowing for reduced pressure on larger bumps and improved mechanical stability of the stacked structure.
Implementation Method 1
an adhesive resin provided between the first and second semiconductor chips and bonding the first and second semiconductor chips
Implementation Method 2
At least one of the first and second semiconductor chips has an organic protective film disposed thereon
Implementation Method 3
a plurality of bumps provided between the first and second semiconductor chips and electrically connecting the first and second semiconductor chips
Data Source
AI summary
A semiconductor device includes a first semiconductor chip, a second semiconductor chip thicker than the first semiconductor chip, a plurality of bumps provided between the first and second semiconductor chips and electrically connecting the first and second semiconductor chips, an adhesive resin provided between the first and second semiconductor chips and bonding the first and second semiconductor chips, and a sealing resin encapsulating the first and second semiconductor chips. At least one of the first and second semiconductor chips has an organic protective film disposed thereon.