Chip-to-Wafer Bonding via Hydrophilic Surface Tension Alignment
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Solution Overview
Problem
Conventional chip-to-wafer 3D integration techniques face challenges with low alignment accuracy due to the trade-off between assembly throughput and alignment precision, particularly in pick-and-place methods.
Innovation Solution
A self-assembly technique is employed where hydrophilic and hydrophobic areas are strategically arranged on the chip and wafer surfaces, with the sum of hydrophilic areas' perimeters being larger than the chip or bonding region's perimeter, allowing for precise alignment under liquid surface tension, and subsequent evaporation for bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick-and-place chip assembly is used for chip-to-wafer bonding, then assembly throughput is improved, but alignment accuracy deteriorates
Solution Approach 1:
The patent employs self-alignment mechanism where liquid surface tension automatically aligns the chip with the bonding region on the wafer. The hydrophilic bonding regions attract liquid而形成液桥，通过液桥的表面张力实现芯片的自动精确定位，无需复杂的外部对准装置，从而在保持高吞吐量的同时实现了高精度对准
Solution Approach 2:
The patent changes the surface energy parameters of the bonding regions by applying hydrophilic treatment to specific areas, creating a contrast between hydrophilic bonding regions and hydrophobic surrounding areas. This parameter change enables selective liquid adhesion and capillary action, which drives the self-alignment process and resolves the contradiction between speed and precision
2Manufacturing precision
If self-assembly technique with liquid is used for chip-to-wafer bonding, then alignment accuracy is improved, but process complexity increases
Solution Approach 1:
The patent segments the wafer surface into distinct hydrophilic bonding regions and hydrophobic surrounding regions. This segmentation allows liquid to be confined to specific bonding locations, creating multiple independent alignment points that collectively achieve high-precision positioning while keeping each individual bonding event simple and robust
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
This method enhances alignment accuracy and stability during chip-to-wafer bonding, improving the precision and reliability of the 3D integration process.
Implementation Method 1
the chips are precisely aligned with the bonding regions under the action of liquid surface tension
Implementation Method 2
subsequent evaporation for bonding
Data Source
AI summary
A chip-to-wafer bonding method and a three-dimensional integrated semiconductor device are provided. The method comprises providing a chip and a wafer having a bonding region of the same size and shape as the chip; preparing hydrophilic areas and hydrophobic areas on the chip; preparing in the bonding region hydrophilic areas and hydrophobic areas respectively corresponding to the hydrophilic and hydrophobic areas on the chip; adding a liquid drop onto the hydrophilic areas in the bonding region; and pre-aligning and placing the chip on the bonding region of the wafer, such that the hydrophilic areas on the chip each contacts the corresponding hydrophilic area in the bonding region via the liquid. The sum of perimeters of the hydrophilic areas on the chip is larger than a perimeter of the chip. The sum of perimeters of the hydrophilic areas in the bonding region is larger than a perimeter of the bonding region.