Direct Chip Bonding with Liquid Film Self-Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for bonding chips to a substrate face challenges such as misalignment and complexity due to varying chip thicknesses, requiring mechanical grips with precise cavities or hydrophilic/hydrophobic modifications, which are costly and difficult to implement.
Innovation Solution
A direct bonding process involving a liquid film, such as deionized water, is formed on the substrate, attracting chips via capillary action, and evaporated to align and bond them, compensating for thickness differences and facilitating collective bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical grip with cavities is used to house chips before bonding, then chips can be held in position, but chips with different thicknesses cannot be aligned in the same plane, causing bonding failures
Solution Approach 1:
A liquid film is introduced as an intermediary substance between the chips and the substrate. This liquid film fills the gaps caused by varying chip thicknesses, enabling all chips to be attracted to and bonded with the substrate simultaneously through capillary forces, thus resolving the alignment issue without requiring precise mechanical cavity depths
Solution Approach 2:
The mechanical grip system with precisely engineered cavities is replaced by a liquid film-based attraction mechanism. Instead of relying on mechanical structures to position chips at precise heights, the invention uses capillary forces from the liquid film to attract and align chips of varying thicknesses to the substrate
2Measurement precision
If self-alignment by capillary action with water drops is used, then chip positioning is achieved, but the process becomes complex requiring hydrophilic and hydrophobic areas on chips
Solution Approach 1:
The invention applies a uniform liquid film across the entire substrate surface rather than requiring heterogeneous hydrophilic and hydrophobic patterns on individual chips. This homogeneous approach simplifies the process by eliminating the need for complex chip surface modifications while still achieving precise positioning through capillary attraction
3Reliability
If self-alignment with water evaporation is used, then chip bonding is achieved, but the cost increases due to required chip modifications
Solution Approach 1:
The invention uses a simple, inexpensive liquid film (water or deionized water) that can be easily applied and evaporated, replacing expensive and complex chip modifications. The liquid film serves its purpose during bonding and then disappears through evaporation, leaving no residue and requiring no permanent alteration to the chips
4Ease of operation
If mechanical grip with cavities is used, then chips can be handled, but precise alignment with substrate features cannot be achieved
Solution Approach 1:
The liquid film acts as a mediator that enables precise alignment between chips and substrate features. As the liquid film evaporates, capillary forces draw the chips into close contact with the substrate, allowing alignment features on the substrate to guide chip positioning with high precision, overcoming the limitations of mechanical grip systems
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 process ensures reliable and efficient bonding of multiple chips to a substrate, aligning them accurately and avoiding defects, while being cost-effective and simpler to implement compared to existing methods.
Implementation Method 1
A direct bonding process involving a liquid film, such as deionized water, is formed on the substrate, attracting chips via capillary action
Implementation Method 2
a stage of evaporation of the liquid film in order to bond the chips to the substrate by direct bonding
Data Source
AI summary
A process for bonding chips to a substrate by direct bonding includes providing a support with which the chips are in contact, the chips in contact with the support being separate from one another. This bonding process also includes forming a liquid film on one face of the substrate, bringing the chips into contact with the liquid film, where the action of bringing the chips into contact with the liquid film causes attraction of the chips toward the substrate, and evaporating the liquid film in order to bond the chips to the substrate by direct bonding.