Silicon-Filled Opening Void Elimination via Mobility Inhibitor Annealing
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Solution Overview
Problem
Semiconductor devices often experience voids or seams in silicon-filled openings due to non-uniform deposition processes, which can adversely impact electronic device performance.
Innovation Solution
A method involving the deposition of an amorphous silicon film on a substrate, followed by exposure to a silicon mobility inhibitor and subsequent annealing at specific temperatures to crystallize and reduce voids without surface roughening, using gases like oxygen or phosphorus-containing species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silicon is deposited at a higher rate at the top of the opening than at the bottom, then the top of the opening closes up first, but voids form in the interior of the opening
Solution Approach 1:
The patent changes the deposition parameters by using low-energy ion bombardment and controlled plasma conditions to achieve uniform silicon deposition throughout the opening, preventing the top-closing phenomenon that creates voids. The deposition is performed at temperatures between 25-150°C with specific pressure and gas flow parameters to ensure uniform growth.
Solution Approach 2:
The patent employs periodic alternation between silicon deposition and oxygen exposure cycles. During deposition, silicon fills the opening; during oxygen exposure, the surface is oxidized. This periodic action allows controlled void elimination through oxidation while maintaining uniform fill, as the oxygen diffuses into voids and causes silicon to redeposit uniformly.
2Manufacturing precision
If voids are eliminated through annealing, then the silicon fill is improved, but surface roughening occurs
Solution Approach 1:
The patent introduces oxygen as an intermediary substance that mediates between void elimination and surface smoothness. Oxygen diffuses into voids during annealing and causes silicon to redeposit uniformly, eliminating voids without the surface roughening that occurs with conventional thermal annealing alone. The oxygen acts as a mediator that enables void healing while preserving surface quality.
Solution Approach 2:
The patent replaces conventional thermal annealing (mechanical heating process) with a chemical-annealing process using oxygen exposure. Instead of relying solely on thermal energy to eliminate voids, which causes surface roughening, the patent uses chemical reactions with oxygen to enable void elimination through controlled oxidation and redeposition, substituting the mechanical thermal process with a chemical process.
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 effectively eliminates or minimizes voids in silicon-filled openings while maintaining a smooth surface, ensuring the silicon fill is crystallized and suitable for integrated circuit structures.
Implementation Method 1
exposing the amorphous silicon film to an oxidizing gas, a nitriding gas, or a phosphorus or arsenic-containing gas
Implementation Method 2
The substrate is heated to an anneal temperature. The substrate is then maintained at the anneal temperature to crystallize the amorphous silicon film in the trench
Implementation Method 3
The substrate is then maintained at the anneal temperature to crystallize the amorphous silicon film in the trench
Implementation Method 4
depositing an amorphous silicon film onto a substrate at a deposition temperature in a deposition chamber
Data Source
AI summary
In some embodiments, silicon-filled openings are formed having no or a low occurrence of voids in the silicon fill, while maintaining a smooth exposed silicon surface. In some embodiments, an opening in a substrate may be filled with silicon, such as amorphous silicon. The deposited silicon may have interior voids. This deposited silicon is then exposed to a silicon mobility inhibitor, such as an oxygen-containing species and/or a semiconductor dopant. The deposited silicon fill is subsequently annealed. After the anneal, the voids may be reduced in size and, in some embodiments, this reduction in size may occur to such an extent that the voids are eliminated.