Wafer Edge Absorbent Layer for Void-Free Direct Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of edge bonding voids during direct wafer bonding in semiconductor technology is problematic due to gas pressure drops and subsequent water droplet condensation at the wafer edge.
Innovation Solution
A wafer structure is designed with a pre-bonding structure that includes an intermediate absorbent layer exposed along the perimeter, which absorbs water molecules at the edge of the wafer, preventing void formation. This structure comprises a substrate, interconnection structure, cap layer, top dielectric layer, and copper pads, with specific materials and thicknesses for each layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct wafer bonding is performed without additional protective structures, then the bonding process is simple and fast, but edge bonding voids form due to water droplet condensation
Solution Approach 1:
An intermediate absorbent layer is introduced between the wafer edge and the bonding interface to absorb water molecules and prevent condensation. This intermediary layer resolves the contradiction by adding a functional element that eliminates the harmful condensation effect without fundamentally changing the bonding process itself.
Solution Approach 2:
The absorbent layer is applied selectively only at the peripheral region of the wafer where edge bonding voids occur, rather than across the entire wafer surface. This localized approach improves bonding quality at the critical edge regions while minimizing the overall structural complexity and material usage.
2Manufacturing precision
If the gas atmosphere is controlled to prevent water droplet condensation, then edge bonding voids are avoided, but the process complexity and cost increase
Solution Approach 1:
Instead of controlling the gas atmosphere to prevent condensation, an intermediate absorbent layer is introduced that passively absorbs water molecules at the bonding interface. This approach achieves the same bonding quality improvement without the complexity of sophisticated gas atmosphere control systems.
Solution Approach 2:
The absorbent layer autonomously absorbs water molecules at the bonding interface without requiring external control systems or additional process steps. The layer performs the protective function self-service, eliminating the need for complex gas atmosphere monitoring and control infrastructure.
3Reliability
If a porous absorbent layer is added to the wafer structure, then water absorption capability improves, but the device structure becomes more complex
Solution Approach 1:
The porous absorbent layer is applied only to the peripheral region of the wafer where water condensation occurs during bonding, rather than across the entire wafer surface. This localized application provides the necessary water absorption capability while minimizing the overall structural complexity and material usage.
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 intermediate absorbent layer effectively traps water molecules at the edge of the wafer, preventing the formation of edge bonding voids and improving the electrical properties and performance of the semiconductor chip.
Implementation Method 1
an intermediate absorbent layer being contiguous with the inner layer and disposed along a perimeter of the outer layer... the intermediate absorbent layer effectively traps water molecules at the edge of the wafer
Implementation Method 2
the intermediate absorbent layer comprises porous dielectric material
Data Source
AI summary
A wafer structure includes a substrate having a pre-bonding structure thereon. The pre-bonding structure includes an outer dielectric layer covering a central region of the substrate and a ring-shaped absorbent layer within a ring-shaped peripheral region of the substrate. The ring-shaped absorbent layer is contiguous with the outer dielectric layer.