H2 Plasma Treatment for Organic Mask Line Width Roughness
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Solution Overview
Problem
Semiconductor wafer processing faces challenges in reducing very low frequency line width roughness (LWR) during etching processes, which affects the precision and quality of feature formation in semiconductor devices.
Innovation Solution
A method involving the use of a hydrogen (H2) treatment gas, where H2 constitutes at least 50% of the treatment gas flow, forming a plasma to treat patterned organic or photoresist masks, and subsequently etching through these masks to reduce very low frequency LWR, with the process being conducted in situ within a plasma processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used, then etching can be performed through the photoresist mask, but very low frequency line width roughness increases affecting feature precision
Solution Approach 1:
The patent applies a hydrogen plasma treatment to the patterned photoresist mask before the etching process. This preliminary action modifies the mask surface properties, specifically reducing very low frequency line width roughness by smoothing line edges. The treatment is performed by flowing hydrogen gas at a flow rate of at least 50% of the total treatment gas flow rate into the plasma chamber, forming plasma, and then stopping the gas flow. This pre-treatment prepares the mask for subsequent etching, ensuring better feature precision.
Solution Approach 2:
The patent changes the chemical and physical parameters of the photoresist mask surface through hydrogen plasma exposure. The plasma treatment alters surface energy, composition, and morphology of the organic mask material. By controlling the hydrogen gas flow rate (at least 50% of total flow) and plasma conditions, the treatment optimally reduces line width roughness without damaging the mask pattern, thereby improving manufacturing precision for the subsequent etching process.
2Manufacturing precision
If multiple process steps are performed separately, then each step can be optimized independently, but process time and complexity increase
Solution Approach 1:
The patent combines the hydrogen plasma treatment step with the subsequent etching process by performing both operations in the same plasma processing chamber. The method involves flowing treatment gas comprising H2 (where H2 flow rate is at least 50% of treatment gas flow rate) to form plasma for mask treatment, then without removing the wafer from the chamber, proceeding with the etching process. This merging eliminates the need for separate treatment and etching chambers, reducing process time and wafer handling while maintaining the precision benefits of the plasma treatment.
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 H2 plasma treatment effectively reduces very low frequency line width roughness, improving the precision and quality of etched features in semiconductor devices by smoothing line edges and reducing roughness, as demonstrated by significant reductions in LWR measurements.
Implementation Method 1
flowing a treatment gas comprising H2, wherein the treatment gas has a flow rate and H2 has a flow rate that is at least 50% of the flow rate of the treatment gas, forming a plasma from the treatment gas
Data Source
AI summary
A method for reducing very low frequency line width roughness (LWR) in forming etched features in an etch layer disposed below a patterned organic mask is provided. The patterned organic mask is treated to reduce very low frequency line width roughness of the patterned organic mask, comprising flowing a treatment gas comprising H2, wherein the treatment gas has a flow rate and H2 has a flow rate that is at least 50% of the flow rate of the treatment gas, forming a plasma from the treatment gas, and stopping the flow of the treatment gas. The etch layer is etched through the treated patterned organic mask with the reduced very low LWR.