Thermal Interface Material Deposition for Bondable Low-Roughness Surfaces
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Solution Overview
Problem
Existing methods for depositing thermal interface materials like aluminum nitride on substrates, such as MOCVD, molecular beam epitaxy, and pulse laser deposition, are uneconomical and have low throughput, while PVD is more cost-effective but lacks efficient methods for achieving suitable surface roughness for bonding.
Innovation Solution
A system and method using PVD to sputter a thermal interface material with a tilted crystallographic orientation, followed by polishing to achieve a surface roughness suitable for fusion, thermal compression, or hybrid bonding, utilizing a PVD chamber and polishing chamber controlled by a controller to achieve a surface roughness of 0.2 to 2 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MOCVD, molecular beam epitaxy, or pulse laser deposition are used to deposit thermal interface material, then the material quality is improved, but the cost increases and throughput decreases
Solution Approach 1:
The patent changes the deposition parameters by using PVD instead of MOCVD or molecular beam epitaxy, and by controlling the sputtering process to create specific crystallographic orientations (c-axis perpendicular to substrate) that enable adequate material quality for bonding while achieving higher throughput and lower cost
2Productivity
If PVD is used to deposit thermal interface material, then cost decreases and throughput increases, but the surface roughness is insufficient for bonding
Solution Approach 1:
The patent changes the sputtering parameters including using a tilted target (e.g., 45-degree angle) to promote preferred crystallographic orientation, controlling deposition temperature, and adjusting sputtering power to achieve both adequate surface roughness for bonding and high throughput
Solution Approach 2:
The patent applies a preliminary sputtering step to create a seed layer with specific crystallographic orientation before final deposition, ensuring that the subsequent layers develop the necessary surface characteristics for bonding while maintaining efficient production
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 method increases throughput and reduces costs by using PVD to deposit thermal interface materials efficiently, achieving the necessary surface roughness for bonding processes.
Implementation Method 1
at least one PVD chamber configured to sputter a layer of aluminum nitride on the substrate
Implementation Method 2
polish the layer until a surface roughness Ra of the layer is 0.2 nm to 2 nm
Data Source
AI summary
Methods and apparatus for processing a substrate include sputtering a first seed layer having a first thickness on the substrate, the first seed layer comprising a thermal interface material having a tilted crystallographic orientation with respect to the substrate; sputtering a second layer having a second thickness on the first seed layer, the second layer comprising the thermal interface material; and polishing the second layer until a surface roughness of the second layer is suitable for at least one of fusion bonding, thermal compression bonding, or hybrid bonding.