3D IC Package Layout Using Dummy Die to Limit Warpage
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high integration density and reducing package size while managing thermal expansion mismatch and warpage issues in three-dimensional integrated circuit (3DIC) packages, particularly due to the complexity of stacking multiple die structures and the need for efficient electrical connectivity.
Innovation Solution
The integration circuit package design includes a first and second die stack bonded to an integrated circuit structure using hybrid bonding, with a dummy die and redistribution layer structure to simplify the process, reduce thermal expansion mismatch, and improve warpage profiles, and an interposer structure with a silicon-free or silicon-containing substrate for efficient electrical routing and reduced package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple die structures are stacked to increase integration density, then integration density is improved, but thermal expansion mismatch and warpage issues worsen
Solution Approach 1:
An interposer structure is introduced as an intermediary component between stacked die structures. The interposer includes a substrate with through-substrate conductive vias and bonding structures that facilitate electrical connectivity while mechanically coupling the die stacks. This intermediary structure helps manage thermal expansion differences and reduces warpage by providing a stable platform that distributes stress across the package, thereby resolving the contradiction between high integration density and structural stability.
Solution Approach 2:
The interposer substrate is formed using composite material structures, including alternating layers of dielectric material and conductive layers. This composite construction allows for tailored thermal and mechanical properties that can compensate for thermal expansion mismatch between different die materials. The layered composite structure provides both electrical functionality and mechanical stability, enabling high integration density while maintaining package integrity under thermal stress.
2Area of stationary object
If multiple die structures are stacked to reduce package size, then package size is reduced, but manufacturing complexity increases
Solution Approach 1:
The interposer structure is prepared in advance with through-substrate conductive vias and bonding structures formed before die stacking. This preliminary preparation of the interposer allows for pre-verification of electrical connectivity and mechanical integrity. By establishing the interposer as a ready-made platform with pre-formed conductive paths and bonding interfaces, the actual die stacking process is simplified, reducing manufacturing complexity despite the three-dimensional architecture.
Solution Approach 2:
The package is segmented into distinct functional modules: the interposer substrate with integrated conductive vias, first die stack with its own bonding structures, and second die stack. Each segment can be independently fabricated, tested, and prepared before final assembly. This segmentation allows for specialized processing of each component and simplifies the overall manufacturing workflow by breaking down the complex three-dimensional integration into manageable stages.
3Reliability
If hybrid bonding is used to bond die stacks to integrated circuit structure, then electrical connectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The bonding structures are designed to self-align during the bonding process. The interposer and die stacks include complementary bonding features that guide precise alignment through mechanical interlocking or geometric constraints. This self-aligning mechanism reduces the stringency of external alignment requirements, allowing hybrid bonding to achieve high electrical connectivity reliability while moderating the manufacturing precision demands through inherent structural guidance.
Data Source
AI summary
Provided are integrated circuit packages and methods of forming the same. An integrated circuit package includes an integrated circuit structure, a first die stack and a dummy die. The first die stack includes a plurality of first die structures and is bonded to the integrated circuit structure at a first side of the first die stack. The dummy die includes a plurality of through substrate vias, is located aside the first die stack and is electrically connected to the integrated circuit structure at the first side of the first die stack. In some embodiments, the height of the through substrate vias of the dummy die is the same as the height of the first die stack.