3DIC Alignment Marks in Seal Ring Regions
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise alignment and efficient bonding in three-dimensional integrated circuits (3DICs) due to the reduced available chip areas when conventional alignment marks are placed within the integrated circuit regions, which limits integration density and increases complexity.
Innovation Solution
The placement of alignment marks within or around the seal ring regions of the dies allows for improved die-to-die alignment without reducing chip area, utilizing a hybrid bonding method that includes metal-to-metal and dielectric-to-dielectric bonding, enabling efficient overlay accuracy inspection and simplifying the layout design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment marks are placed within the integrated circuit regions, then alignment precision can be achieved, but chip area is reduced and layout complexity increases
Solution Approach 1:
The alignment marks are extracted from the integrated circuit regions and relocated to the seal ring regions, which are peripheral areas that do not interfere with the functional circuit layout. This extraction allows the alignment marks to be positioned in available space without consuming valuable chip area dedicated to integrated circuits.
Solution Approach 2:
The alignment marks are positioned in the peripheral seal ring regions rather than within the central integrated circuit area, effectively utilizing the boundary dimension of the chip. This dimensional repositioning allows alignment functionality to coexist with high-density circuit integration in the central region.
2Measurement precision
If alignment marks are placed within the integrated circuit regions, then alignment can be performed, but layout complexity increases
Solution Approach 1:
By extracting alignment marks from the integrated circuit regions to the seal ring regions, the layout design is simplified. The seal ring regions serve as dedicated peripheral zones that can accommodate alignment marks without interfering with the complex interconnect patterns and device layouts in the central circuit areas.
3Reliability
If conventional bonding methods are used, then bonding can be achieved, but integration density is limited
Solution Approach 1:
The patent combines multiple bonding approaches (metal-to-metal bonding and dielectric-to-dielectric bonding) into a hybrid bonding method. This merging of bonding techniques enables direct die-to-die bonding with improved integration density while maintaining bonding reliability through the complementary advantages of both bonding methods.
Data Source
AI summary
Three-dimensional integrated circuit (3DIC) structures are disclosed. A 3DIC structure includes a first die and a second die bonded to the first die. The first die includes a first integrated circuit region and a first seal ring region around the first integrated circuit region, and has a first alignment mark within the first integrated circuit region. The second die includes a second integrated circuit region and a second seal ring region around the second integrated circuit region, and has a second alignment mark within the second seal ring region and corresponding to the first alignment mark.