Stacked Die Package Alignment Using Embedded Bonding Marks
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Solution Overview
Problem
Integration of multiple semiconductor devices in wafer level packaging poses challenges, particularly in achieving precise alignment and efficient electrical connections between dies.
Innovation Solution
A method involving fusion bonding of dies to a carrier substrate, followed by sequential deposition of dielectric and bonding layers, and hybrid bonding of additional dies to form a reconstructed wafer with improved alignment and electrical connectivity through bonding vias and pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple semiconductor devices are integrated at wafer level, then productivity and integration density are improved, but manufacturing precision and alignment difficulty worsen
Solution Approach 1:
The wafer is divided into multiple individual dies that can be processed and packaged separately yet remain on the wafer substrate. This segmentation allows each die to be handled independently for precise alignment while maintaining overall wafer-level integration, resolving the contradiction between high integration density and alignment precision.
Solution Approach 2:
A carrier substrate is introduced as an intermediary between the dies and the final package. The carrier substrate provides a stable platform for wafer-level processing and enables precise positioning of multiple dies during bonding operations, thereby achieving both high integration and manufacturing precision.
2Productivity
If wafer level packaging is used, then productivity is improved, but device complexity increases
Solution Approach 1:
Multiple packaging operations are merged into a single wafer-level process. Instead of packaging each die individually, the method combines die attachment, bonding layer formation, and electrical connection establishment into integrated wafer-level steps, thereby improving productivity while managing process complexity through consolidation.
Solution Approach 2:
The wafer-level packaging process serves multiple functions simultaneously: it performs die attachment, forms bonding layers, creates electrical connections, and enables subsequent die stacking. This multi-functionality improves packaging efficiency while the standardized universal process reduces overall complexity compared to multiple separate operations.
3Manufacturing precision
If precise alignment is achieved between dies, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
Alignment marks are pre-formed on the carrier substrate and dies before the bonding process. This preliminary action enables rapid automated alignment during packaging without requiring time-consuming manual adjustment, thereby achieving high alignment precision while minimizing the time lost during the alignment process.
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
Enhances yield and reduces costs by ensuring high precision alignment and efficient electrical connections, facilitating the integration of known good dies in a reconstructed wafer.
Implementation Method 1
The first bonding layer is fusion bonded to the carrier substrate
Implementation Method 2
The third bonding layer is hybrid bonded to the second bonding layer of the first die
Data Source
AI summary
A package includes a carrier substrate, a first die, and a second die. The first die and the second die are stacked on the carrier substrate in sequential order. The first die includes a first bonding layer, a second bonding layer, and an alignment mark embedded in the first bonding layer. The second die includes a third bonding layer. A surface of the first bonding layer form a rear surface of the first die and a surface of the second bonding layer form an active surface of the first die. The rear surface of the first die is in physical contact with the carrier substrate. The active surface of the first die is in physical contact with the third bonding layer of the second die.