AlN Substrate Pore Filling via Sputtering and Sintering
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Solution Overview
Problem
Existing methods for preparing aluminum nitride (AlN) substrates do not effectively address the issue of surface pore treatment optimization, leading to reduced substrate strength, thermal conductivity, and surface flatness, which impacts the efficiency of high-power semiconductor processing and optical reflector applications.
Innovation Solution
A method involving surface grinding, polishing, high-temperature sintering, and two stages of aluminum nitride (AlN) film deposition is used to fill surface pores, enhancing adhesion and density, with reactive magnetron sputtering technology to form dense AlN films on polycrystalline AlN substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional sintering methods are used to prepare AlN substrates, then thermal conductivity is improved, but surface pore sizes remain large and surface flatness deteriorates
Solution Approach 1:
The patent applies preliminary action by performing surface grinding and polishing before sintering to reduce surface pores and improve flatness. This preliminary surface treatment ensures that the substrate has optimal surface quality before the high-temperature sintering process, preventing pore formation during sintering and maintaining surface flatness while achieving high thermal conductivity.
Solution Approach 2:
The patent employs parameter changes by controlling the sintering temperature (1500-1800°C) and holding time (1-4 hours) to optimize both thermal conductivity and surface quality. By carefully adjusting these parameters, the substrate achieves high thermal conductivity while minimizing pore formation and maintaining surface flatness through controlled densification.
2Temperature
If high-temperature sintering is applied to densify the substrate, then thermal conductivity improves, but surface pores increase and strength decreases
Solution Approach 1:
The patent applies preliminary action by performing surface grinding and polishing before sintering to pre-reduce surface pores and improve surface flatness. This preliminary treatment ensures that the substrate starts with optimal surface quality, preventing excessive pore formation during high-temperature sintering and maintaining both strength and thermal conductivity.
Solution Approach 2:
The patent uses parameter changes by optimizing sintering temperature (1500-1800°C) and holding time (1-4 hours) to achieve the right balance between densification and strength preservation. This controlled parameter adjustment ensures sufficient thermal conductivity while preventing excessive pore formation that would compromise substrate strength.
3Manufacturing precision
If surface pores are filled with deposition methods, then surface flatness improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by performing surface grinding and polishing before sintering to pre-reduce surface pores and improve flatness. This preliminary mechanical treatment is simpler and more direct than post-sintering deposition methods, achieving surface flatness improvement without adding complex deposition process steps.
Solution Approach 2:
The patent extracts the surface pore filling function from complex multi-step deposition processes and implements it through a simplified sequence of surface grinding, polishing, and controlled sintering. This extraction approach removes unnecessary complexity while achieving the same surface quality improvement.
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 results in AlN substrates with low surface pore sizes, high thermal conductivity, and improved bending-resistant strength, suitable for high thermal dissipation and miniaturized electronic components.
Implementation Method 1
reactive magnetron sputtering technology to form dense AlN films on polycrystalline AlN substrates
Implementation Method 2
forming a first AlN film on a surface of the AlN substrate to fill lattice defect pores on the surface of the AlN substrate, wherein the first AlN film is formed by plasma for reactive sputtering
Implementation Method 3
The planar AlN substrate is sintered under high-temperature to enhance the adhesion of the AlN film within the lattice defect pores with the substrate
Data Source
AI summary
A method for preparing an AlN substrate includes: (A) providing a surface-polished polycrystalline aluminum nitride (AlN) substrate; (B) forming a first AlN film via reactive sputtering using magnetron sputtering with an aluminum target, nitrogen, and argon gases to fill surface lattice defect pores; (C) removing the first AlN film by thinning and polishing, leaving filled pore areas to form a planar AlN substrate; (D) sintering the planar substrate at high temperature to enhance adhesion; (E) forming a second AlN film on the sintered AlN substrate; (F) removing the second AlN film by thinning and polishing to achieve a final AlN substrate with high thermal conductivity and low surface pore sizes.