Structured Substrate Preparation with Sacrificial Protective Layer
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Solution Overview
Problem
Existing methods for preparing structured substrates for direct bonding, particularly those with Cu/SiO2 hybrid surfaces, face challenges in achieving high-quality bonding due to aggressive cleaning processes that degrade the surface roughness and are unable to polish edges effectively, leading to poor bonding quality.
Innovation Solution
A method involving a protective layer with controlled adhesion energy is used to prepare structured substrates, where a protective layer is bonded to a thin layer, resin openings are formed, and the protective layer is separated from the substrate, ensuring the resin is removed at a lower adhesion interface, preserving the thin layer's surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma cleaning processes combined with wet cleaning are used to remove resin, then complete resin removal is achieved, but the surface roughness is degraded and surface quality is damaged
Solution Approach 1:
A protective layer is introduced as an intermediary between the resin and the thin layer. This protective layer serves as a sacrificial element that absorbs the aggressive cleaning action, protecting the underlying thin layer surface from damage while still allowing complete resin removal through standard plasma and wet cleaning processes
Solution Approach 2:
The protective layer is deposited on the thin layer before resin application. This preliminary protective coating prevents direct contact between the aggressive cleaning chemicals and the sensitive thin layer surface, allowing subsequent resin removal without surface degradation
2Manufacturing precision
If chemical-mechanical polishing is used to prepare the hybrid surface, then surface smoothness is improved, but subsequent structuring causes edge rounding that prevents bonding
Solution Approach 1:
The protective layer is applied before structuring operations. This preliminary protection allows the thin layer to maintain its polished smoothness while the protective layer absorbs the mechanical stress of structuring, preventing edge rounding of the underlying bonding surface
Solution Approach 2:
The protective layer acts as a mediator that decouples the structuring process from the bonding surface. It allows structuring to proceed without directly affecting the thin layer edges, preserving bonding capability while maintaining surface smoothness
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 produces high-quality structured substrates suitable for direct bonding by maintaining the integrity of the thin layer surface, avoiding degradation and ensuring effective bonding without the need for aggressive cleaning.
Implementation Method 1
bonding a protective layer to the thin layer by direct bonding
Implementation Method 2
the adhesion energy between the protective layer and the thin layer is less than the adhesion energy between the temporary substrate and the protective layer
Data Source
Figure 1A~2F
Figure 2G~4F
Figure 4G~5H
AI summary
The present description relates to a method for preparing a structured substrate of interest (100) comprising the following steps: - providing a substrate of interest (100) comprising a thin layer (120), on which a protective layer (220) has been bonded by direct bonding, - depositing a resin (300), and etching the thin layer (120) and a part of the support substrate (110) through openings in the resin, to form pads, - bonding a temporary substrate (200) to the substrate of interest (100), then separating them, whereby the protective layer (220) is separated from the substrate of interest (100), the resin (300) being removed before the bonding step or during the separation, the protective layer (220) / thin layer (120) adhesion energy being lower than the temporary substrate (400) / protective layer (220) adhesion energy or the resin (300) / protective layer (220).