Transfer Printing Alignment via Non-Orthogonal Walls
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Solution Overview
Problem
Conventional methods for combining independently formed integrated circuit dice face challenges in precise alignment and electrical connection, particularly when dealing with disparate materials like III-V semiconductor devices and CMOS devices, due to lattice mismatch and incompatible fabrication processes.
Innovation Solution
A transfer printing method that uses a die moving member and alignment structures, such as non-orthogonally oriented walls or magnetic/electrostatic controls, to precisely position and integrate dice on a receiving wafer, allowing for the combination of dice with different circuitry types, like III-V and CMOS, without requiring highly precise equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional transfer printing processes are used to combine independently formed integrated circuit dice, then the process can handle disparate materials like III-V semiconductor devices and CMOS devices, but alignment precision deteriorates due to lattice mismatch and incompatible fabrication processes
Solution Approach 1:
The patent introduces an intermediary alignment structure consisting of non-orthogonally oriented walls on the receiving wafer. These walls act as a mediator between the die moving member and the target position, guiding the die into precise alignment through mechanical constraint rather than relying on precise positioning equipment. The slanted walls convert lateral movement into vertical positioning, enabling accurate alignment even when combining dice from different fabrication processes with lattice mismatch.
2Manufacturing precision
If highly precise equipment is used to position dice for electrical connection, then alignment precision improves, but device complexity and cost increase
Solution Approach 1:
The alignment structure enables self-alignment of the die during the transfer process. The non-orthogonal walls automatically guide the die into the correct position through mechanical interaction, eliminating the need for complex external positioning equipment. The system uses its own structural features (the slanted walls) to achieve precise alignment, making the process self-sufficient and reducing equipment complexity.
3Device complexity
If conventional mechanical coupling processes are used to combine integrated circuit dice, then the process is simple, but parasitic effects increase and footprint enlarges
Solution Approach 1:
The patent transitions from conventional planar mechanical coupling to a three-dimensional integration approach. The die is positioned on a receiving wafer surface and electrically connected through vertical vias and conductive structures, utilizing the vertical dimension for interconnections. This 3D integration reduces parasitic effects by shortening connection paths and decreases footprint by stacking components vertically rather than arranging them horizontally.
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
Enables the formation of monolithic integrated circuits with reduced parasitics, smaller footprint, and the capability for parallel processing, facilitating the integration of diverse circuitry types like III-V and CMOS, which would be difficult with traditional coupled processes.
Implementation Method 1
removes a second die from a second wafer using a die moving member
Implementation Method 2
The alignment structure may include a magnetic structure configured to at least in part control movement of the die moving member
Implementation Method 3
The alignment structure may include electrostatic structure configured to at least in part control movement of the die moving member
Data Source
AI summary
A transfer printing method provides a first wafer having a receiving surface, and removes a second die from a second wafer using a die moving member. Next, the method positions the second die on the receiving surface of the first wafer. Specifically, to position the second die on the receiving surface, the first wafer has alignment structure for at least in part controlling movement of the die moving member.