Hybrid Bonding of Organic Insulating Layers With Plasma Leveling
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Solution Overview
Problem
The hybrid bonding technique in semiconductor devices using organic materials for insulating portions faces issues due to thermal expansion differences between metal and organic materials, leading to bonding failures at the insulating and terminal electrode interfaces.
Innovation Solution
A method involving plasma etching is used to adjust the level difference between the surface of the organic insulating layer and the tip end surface of the electrode by varying plasma conditions based on the materials' elastic modulus, followed by polishing to reduce surface roughness and ensure precise alignment before hybrid bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is applied to both the organic insulating layer and the electrode, then the level difference can be adjusted, but the surface roughness increases due to plasma bombardment
Solution Approach 1:
The patent applies preliminary polishing to the organic insulating layer and electrode surfaces before plasma etching. This preliminary action removes the roughness that will be generated during subsequent plasma etching, ensuring that the bonding surfaces remain smooth while still achieving the desired level difference through controlled plasma etching of the insulating layer only
Solution Approach 2:
The patent extracts the polishing step to be performed separately and sequentially before plasma etching, rather than attempting to achieve both smooth surfaces and level difference in a single step. This separation allows the polishing process to prepare smooth surfaces while the subsequent plasma etching creates the necessary level difference
2Productivity
If the flow rate of plasma gas is increased to promote etching, then the level difference is achieved faster, but the surface roughening increases
Solution Approach 1:
By performing polishing before plasma etching, the patent creates a buffer that allows higher plasma gas flow rates to be used during etching without compromising the final surface roughness. The preliminary polishing removes the roughness that would otherwise be generated by aggressive plasma etching conditions
Solution Approach 2:
The patent applies excessive polishing action before plasma etching to over-compensate for the roughness that will be generated during etching. This ensures that even with high plasma gas flow rates that promote rapid etching, the final surface roughness remains within acceptable limits
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 facilitates reliable bonding by minimizing thermal expansion-induced shifts and reducing bonding failures, ensuring accurate and stable connections between semiconductor substrates.
Implementation Method 1
irradiating a surface of the first semiconductor substrate with plasma. In the irradiating with plasma, at least the first organic insulating layer is etched with plasma
Data Source
AI summary
As an example, the present invention relates to a hybrid bonding method using an organic insulating layer as an insulating layer. In the hybrid bonding method using an organic insulating layer, there may be a difference in thermal expansion between a terminal electrode made of metal or the like and the organic insulating layer due to heating at the time of bonding, and it is necessary to provide a predetermined level difference D between a tip end surface of the terminal electrode and a surface of the organic insulating layer in advance. In the present invention, in order to provide the level difference D, the surface of the semiconductor substrate 100 is irradiated with plasma (e.g. argon plasma). In this plasma irradiation, an organic insulating layer 102 is etched with plasma such that a surface 102a of the organic insulating layer 102 of the semiconductor substrate 100 is on the farther side than a tip end surface 103a of an electrode 103.