Cluster Tool Vacuum Transfer for DRAM Bit Line Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DRAM bit line stack processes face issues with oxidation occurring on substrates due to exposure to atmospheric pressure, leading to resistance drawbacks and material property degradation, as multiple tools are used for various processes on a polysilicon plug substrate.
Innovation Solution
A cluster tool is employed for DRAM bit line stack processes, featuring a front-end module, vacuum transfer modules, and multiple processing chambers that maintain a vacuum environment throughout the process, allowing for sequential performance of pre-cleaning, barrier metal deposition, barrier layer deposition, bit line metal deposition, and hard mask deposition without exposing the substrate to atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple independent tools are used for DRAM bit line stack processes, then process versatility is improved, but substrate exposure to atmospheric pressure causes oxidation and material degradation
Solution Approach 1:
The patent combines multiple independent processing tools into a single cluster tool system that maintains continuous vacuum conditions. The cluster tool integrates deposition chambers, annealing chambers, and transport modules, allowing multiple DRAM bit line stack processes to be performed sequentially without breaking vacuum, thereby preventing oxidation while maintaining process versatility.
Solution Approach 2:
The patent employs a continuous vacuum environment as an inert atmosphere throughout the entire processing sequence. By maintaining vacuum conditions during substrate transport between chambers and during all processing steps, the system prevents atmospheric oxidation of the substrate and deposited films, eliminating the harmful oxidation effect while preserving multi-process capability.
2Device complexity
If substrate is exposed to atmospheric pressure between processes, then tool complexity is reduced, but resistance increases and material properties degrade
Solution Approach 1:
The patent consolidates multiple processing functions into an integrated cluster tool that maintains continuous vacuum. By combining deposition, annealing, and transport functions within a single vacuum-based system, the patent avoids the need to break vacuum for tool transitions, thereby preventing oxidation-related resistance increases and material degradation while managing system complexity through integration.
Solution Approach 2:
The patent ensures continuous vacuum conditions are maintained throughout the entire processing sequence without interruption. The substrate remains under vacuum during all processing steps and transport operations, eliminating exposure to atmospheric pressure that would cause oxidation. This continuous action approach preserves material properties and prevents resistance increases while maintaining reliable processing.
3Object-affected harmful factors
If vacuum environment is maintained throughout processing, then oxidation is prevented, but device complexity increases
Solution Approach 1:
The patent employs a continuous vacuum environment as an inert atmosphere to prevent oxidation of the substrate and deposited films during all processing steps. The cluster tool is designed to maintain vacuum conditions during deposition, annealing, and transport operations, effectively eliminating oxidation while managing the inherent complexity through systematic integration of vacuum maintenance across all modules.
Solution Approach 2:
The patent designs the cluster tool with universal vacuum-based processing capabilities that can perform multiple DRAM bit line stack processes including deposition, annealing, and transport. By creating a multi-functional system that handles all processing steps within a continuous vacuum environment, the patent prevents oxidation while consolidating complexity into a single versatile platform rather than multiple separate tools.
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 reduces oxidation and maintains a consistent vacuum environment, minimizing material degradation and enabling a broader selection of bit line metal materials by preventing oxidation during the fabrication process, thus improving the quality and reliability of the substrate.
Implementation Method 1
oxidation on the deposited films, which can be caused by exposing the substrate to atmospheric pressure conditions
Implementation Method 2
barrier metal deposition, barrier layer deposition, bit line metal deposition, and hard mask deposition
Data Source
AI summary
Methods and apparatuses for substrate fabrication are provided herein. The apparatus, for example, can include a cluster tool including a vacuum transfer module (VTM) configured to receive, under vacuum conditions, a silicon substrate with a polysilicon plug (poly plug) and transfer, without vacuum break, the substrate to and from a plurality of processing chambers each independently connected to the VTM for performing a corresponding one of a plurality of DRAM bit line processes on the substrate, the plurality of processing chambers comprising a pre-cleaning chamber configured to remove native oxide from a surface of the substrate, a barrier metal deposition chamber configured to deposit the barrier metal on the surface of the poly plug on the silicon substrate, a barrier layer deposition chamber configured to deposit at least one material on the surface of the barrier metal, a bit line metal deposition chamber configured to deposit at least one material on the surface of the barrier layer, and a hard mask deposition chamber configured to deposit at least one material on the surface of the bit line metal.