Semiconductor Substrate Cleaning via Dynamic Protecting Liquid Thickness Control
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Solution Overview
Problem
The existing double feature type cleaning process for semiconductor substrates faces challenges in achieving effective detergency while minimizing pattern damage, as the thickness of the protecting liquid affects the distribution and pressure of cleaning droplets, leading to either reduced cleaning efficiency or pattern damage.
Innovation Solution
A method and apparatus that involve spraying a protecting liquid from two different positions along distinct spray directions on a semiconductor substrate, ensuring uniform thickness and controlled injection of cleaning droplets from edge to center and vice versa, utilizing a cleaning droplet-injecting unit and a protecting liquid-spraying unit with a thickness sensor and controller to adjust the spray flux and height accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protecting liquid is sprayed thickly to protect patterns from damage, then pattern protection is improved, but detergency decreases because cleaning liquid cannot reach the pattern sufficiently
Solution Approach 1:
The spray flux of the protecting liquid is dynamically adjusted based on the thickness of the protecting liquid film. When the film thickness is insufficient, the spray flux is increased to build up protection; when the film is too thick, the spray flux is reduced to allow cleaning liquid penetration. This dynamic control resolves the contradiction between pattern protection and detergency.
Solution Approach 2:
The thickness of the protecting liquid film is controlled by adjusting spray parameters (spray flux, spray height, spray angle) to achieve an optimal range. This parameter optimization ensures the protecting liquid is thick enough to protect patterns but thin enough to allow cleaning liquid to reach and clean the pattern surface, resolving the contradiction between protection and detergency.
2Productivity
If the protecting liquid is sprayed thinly to allow cleaning liquid penetration, then detergency is improved, but pattern damage occurs due to high injection pressure of cleaning droplets
Solution Approach 1:
The spray flux of the protecting liquid is dynamically adjusted based on the thickness of the protecting liquid film. When the film thickness is insufficient, the spray flux is increased to build up protection; when the film is too thick, the spray flux is reduced to allow cleaning liquid penetration. This dynamic control resolves the contradiction between pattern protection and detergency.
Solution Approach 2:
The thickness of the protecting liquid film is controlled by adjusting spray parameters (spray flux, spray height, spray angle) to achieve an optimal range. This parameter optimization ensures the protecting liquid is thick enough to protect patterns but thin enough to allow cleaning liquid to reach and clean the pattern surface, resolving the contradiction between protection and detergency.
3Productivity
If cleaning droplets are injected with high pressure to improve cleaning efficiency, then detergency is improved, but pattern damage increases
Solution Approach 1:
The protecting liquid serves as an intermediary layer between the cleaning droplets and the pattern. It absorbs and distributes the impact pressure of the cleaning droplets, preventing direct high-pressure contact with the pattern while still allowing cleaning liquid to penetrate and clean the pattern surface, thus resolving the contradiction between cleaning efficiency and pattern damage.
Solution Approach 2:
The protecting liquid is sprayed beforehand to create a cushioning layer that protects the pattern from the high-pressure impact of cleaning droplets. This pre-established protective layer allows high-pressure cleaning to be applied without causing pattern damage, resolving the contradiction between cleaning efficiency and pattern integrity.
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 enhances cleaning efficiency by maintaining uniform protecting liquid thickness, reducing pattern damage, and optimizing the removal of byproducts from the substrate.
Implementation Method 1
cleaning droplets may be injected on the first portion of the surface of the substrate
Implementation Method 2
a protecting liquid may be sprayed on a first portion of a surface of the substrate from a first position along a first spray direction
Data Source
AI summary
In a method of cleaning a substrate, a protecting liquid may be sprayed to a surface of the substrate from a first position in a first spray direction. Cleaning droplets may be injected on to the surface of the substrate. The protecting liquid may be sprayed to the surface of the substrate from a second position different from the first position in a second spray direction. For example, the protecting liquid may be always sprayed from the central portion toward the edge portions in the substrate so that the protecting liquid on the substrate may have a uniform thickness.