Semiconductor Recess Filling via Rough-Surface Metal Bonding
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Solution Overview
Problem
Current methods for manufacturing semiconductor elements with bonding steps are complex and costly, often resulting in incomplete filling of recesses which can lead to reduced bonding strength, electrical characteristics, and heat dissipation.
Innovation Solution
A method involving the formation of rough-surface portions within recesses using a plating technique, where a first metal layer is bonded to a second metal layer while heating and pressing, allowing the melted metal to flow into recesses and fill them effectively, reducing the need for thick metal films and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bonding methods are used to bond two members with recesses, then the manufacturing process can be performed, but the recesses are not completely filled resulting in reduced bonding strength, electrical characteristics, and heat dissipation
Solution Approach 1:
The patent applies preliminary action by forming rough-surface portions at the bottom of recesses before the bonding step. These rough-surface portions are created by depositing a metal layer and selectively removing portions to expose the underlying semiconductor layer, which then serves to guide and facilitate complete filling of the recesses during subsequent bonding, thereby improving filling completeness and bonding strength
Solution Approach 2:
The patent applies local quality by creating rough-surface portions only at specific locations (the bottom of recesses) rather than uniformly across the entire surface. This localized roughening is achieved by selective removal of metal layers in recess regions, providing enhanced metal flow guidance and filling capability precisely where needed, without affecting other areas of the structure
2Manufacturing precision
If thick metal films are used to ensure complete filling of recesses, then filling completeness improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary action by pre-forming rough-surface portions in the recesses before bonding. These rough-surface portions act as nucleation sites that guide metal flow during bonding, enabling complete filling of recesses with thinner metal layers than would be required without such preliminary structuring, thereby reducing overall device complexity
Solution Approach 2:
The patent replaces the mechanical approach of using thick metal films to force filling of recesses with a more efficient mechanism: rough-surface portions that chemically and physically guide metal flow during bonding. This substitution allows achieving complete filling with thinner metal layers, reducing material requirements and simplifying the structure
3Productivity
If conventional bonding processes are used, then the manufacturing steps can be completed, but the process complexity and manufacturing cost remain high
Solution Approach 1:
The patent merges multiple functions into the rough-surface portion formation step: the deposited metal layer serves as both a structural element and a template for creating rough-surface portions. This integrated approach combines what would otherwise be separate processes (metal deposition, pattern definition, and surface preparation) into a unified manufacturing step, reducing overall process complexity
Solution Approach 2:
The rough-surface portions are formed using the metal layer itself as the material source, eliminating the need for separate sacrificial materials or additional processing steps. The metal layer that will eventually fill the recesses during bonding is the same material used to create the rough-surface portions, allowing the structure to prepare its own filling pathways without external intervention
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 approach enhances bonding strength, electrical characteristics, and heat dissipation while reducing manufacturing costs by ensuring complete filling of recesses without the need for high-thickness metal films, thereby simplifying the manufacturing steps.
Implementation Method 1
heating the first metal layer and the second metal layer in a state in which the first metal layer and the second metal layer face each other such that the first metal layer and the second metal layer are melted and bonded together
Implementation Method 2
the first metal layer and the second metal layer are melted and bonded together
Implementation Method 3
a third metal layer is disposed along an inner surface of the first recess in at least a portion of the first recess to form the first rough-surface portion
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
A method of manufacturing a semiconductor element includes: a first providing step comprising providing a structure body comprising a semiconductor stacked body, the structure body including first surfaces that include surfaces defining at least one first recess; a first forming step comprising forming a first rough-surface portion at or inward of at least a portion of the surfaces defining the first recess of the structure body; a second forming step comprising forming a first metal layer at a first surface side of the structure body; a second providing step comprising providing a substrate on which a second metal layer is disposed; and a bonding step comprising heating the first metal layer and the second metal layer in a state in which the first metal layer and the second metal layer face each other.