Ultra-Thin Semiconductor Wafer Stacking with Stop-Layer Thinning
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Solution Overview
Problem
Existing semiconductor technologies face limitations in achieving high integration and high speed due to the constraints of planar packaging, necessitating innovative methods for miniaturization and stacking of semiconductor wafers.
Innovation Solution
A method for manufacturing a semiconductor stack structure with ultra-thin dies involves forming a stop layer structure in semiconductor wafers, flipping and bonding them, and performing backside grinding and thinning processes to achieve ultra-thin semiconductor wafers, allowing for multiple layers to be stacked while maintaining electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If planar packaging technology is used to achieve high integration, then the circuit size can be reduced, but the packaging efficiency and integration density reach their limits
Solution Approach 1:
The patent transitions from planar 2D packaging to 3D vertical stacking architecture. Multiple semiconductor wafers are stacked in the thickness direction to form a three-dimensional structure, enabling high integration density without further reducing circuit size. The wafer stacking structure includes bottom support wafers, intermediate functional wafers, and top cap wafers, creating vertical interconnection pathways that dramatically increase packaging capacity.
2Speed
If multiple semiconductor wafers are stacked to improve operating speed, then integration is enhanced, but the manufacturing precision and alignment difficulty increase
Solution Approach 1:
The patent introduces intermediate support wafers and cap wafers as intermediary structural elements between functional semiconductor wafers. These intermediary layers provide mechanical support, stress relief, and alignment reference surfaces, facilitating precise stacking of multiple functional wafers. The support structures act as mediators that enable high-precision alignment while accommodating manufacturing tolerances.
3Productivity
If the thickness of semiconductor wafers is reduced to enable higher stacking, then integration density improves, but the mechanical strength and handling difficulty deteriorate
Solution Approach 1:
The patent combines multiple ultra-thin functional wafers with thicker support wafers and cap wafers in a composite stacking structure. The support wafers and cap wafers provide mechanical strength and structural integrity, while the thin functional wafers enable high integration density. This merging of different wafer thickness types creates a composite structure that simultaneously achieves high stacking density and adequate mechanical strength for handling.
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 method enables high integration and high speed performance by allowing up to 57 layers of ultra-thin semiconductor chips to be stacked, with improved electrical characteristics and efficiency.
Implementation Method 1
the silicon nitride layer is manufactured by carrying out a nitrogen ion implantation process at a first depth of the semiconductor substrate firstly and then carrying out a high temperature treatment process to form the silicon nitride layer in a nitrogen ion implanted region
Implementation Method 2
carrying out a high temperature treatment process to form the silicon nitride layer in a nitrogen ion implanted region
Implementation Method 3
carrying out a first backside grinding process from the backside of the second semiconductor wafer to remove a portion of the second substrate part of the second semiconductor wafer
Implementation Method 4
enabling the inner connection layer of the first semiconductor wafer and the inner connection layer of the second semiconductor wafer to be opposite to each other and bonded together by hybrid bonding
Data Source
AI summary
A method for manufacturing a semiconductor stack structure with an ultra-thin die includes: forming a stop layer structure inside a semiconductor substrate by ion implantation, and then providing electrical components and an inner connection layer on an active surface of the semiconductor substrate to form a semiconductor wafer; enabling inner connection layers of two semiconductor wafers to be opposite and bonded together up and down; removing part of the semiconductor substrate and the stop layer structure of the upper one of the semiconductor wafers from a backside of the upper one of the semiconductor wafers through a backside grinding process and a thinning process, enabling the upper one of the semiconductor wafers to form a thinned semiconductor wafer; carrying out bonding, backside grinding and thinning processes on the other semiconductor wafer one by one on the thinned semiconductor wafer to stack another thinned semiconductor wafer upwards one by one; and finally, carrying out backside grinding and thinning processes on a semiconductor wafer at a bottom. By means of the manufacturing method, a plurality of layers of thinned semiconductor wafers can be stacked, and the requirement for high integration is met.