Etching Method Using Periodic Microwave Heating for By-Product Removal
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Solution Overview
Problem
During the etching of silicon-containing or metal-containing films, by-products such as ammonium fluorosilicate can cause etching failures like shape deterioration or etching stop due to low volatility at low substrate temperatures, leading to inefficient processing.
Innovation Solution
The etching method involves temporarily heating the substrate with electromagnetic waves, such as microwaves, during the etching process to volatilize and remove the by-products, while maintaining the substrate at a temperature lower than the sublimation point of the by-products to prevent plasma disruption and ensure continuous etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate temperature is kept low during etching, then plasma stability is maintained, but by-products accumulate and cause etching failures
Solution Approach 1:
The patent applies periodic heating cycles during the etching process. The substrate is heated at specific intervals (e.g., every 30 seconds to several minutes) for short durations (e.g., 1 second to several seconds) to volatilize by-products, then cooled to maintain plasma stability. This periodic temperature modulation resolves the contradiction by temporarily raising temperature to remove by-products without disrupting overall plasma conditions.
Solution Approach 2:
The patent dynamically changes the substrate temperature parameter during etching. By controlling temperature transitions between low (for plasma stability) and high (for by-product removal) states, the system optimizes both plasma maintenance and by-product elimination. The temperature is adjusted based on etching progress, by-product accumulation level, and process requirements.
2Manufacturing precision
If the substrate temperature is increased to remove by-products, then etching quality improves, but plasma stability deteriorates
Solution Approach 1:
The patent uses periodic heating pulses rather than continuous heating. Short heating bursts raise the substrate temperature sufficiently to volatilize by-products and improve etching quality, then rapid cooling restores plasma stability. This temporal separation allows both high precision and plasma stability to coexist at different moments in the cycle.
Solution Approach 2:
The patent exploits the phase transition of by-products from solid/liquid to gas through controlled heating. By raising the substrate temperature above the sublimation or boiling point of by-products temporarily, the system transforms accumulated by-products into volatile gas phase substances that can be removed by vacuum pumping, thereby improving etching quality without permanent plasma disruption.
3Reliability
If continuous heating is applied to remove by-products, then etching failures are suppressed, but energy consumption increases and plasma is disrupted
Solution Approach 1:
The patent implements intermittent heating instead of continuous heating. Heating is applied only when by-product accumulation reaches critical levels or at predetermined intervals, rather than continuously throughout the etching process. This reduces energy consumption significantly while maintaining etching process reliability by removing by-products at key moments.
Solution Approach 2:
The patent maintains continuous etching operation while applying periodic heating for by-product removal. The etching process continues uninterrupted, and the periodic heating serves to clear by-products that would otherwise accumulate and cause failures. This ensures continuous useful action (etching) with minimal energy input for by-product management.
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 effectively suppresses etching failures by periodically sublimating and removing by-products, allowing for high etching rates and preventing shape deterioration, even at low substrate temperatures, thus enhancing the etching process efficiency.
Implementation Method 1
heating the substrate by temporarily irradiating the substrate with electromagnetic waves during the etching
Implementation Method 2
periodically sublimating and removing by-products
Data Source
AI summary
An etching method include: etching a silicon-containing film or a metal-containing film formed on a substrate; and heating the substrate by temporarily irradiating the substrate with electromagnetic waves during the etching.