Protective Film Surface Control for Plasma-Exposed Structural Members
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Solution Overview
Problem
Existing protective films on structural members in semiconductor manufacturing equipment deteriorate and form large particles when exposed to plasma, leading to process disruptions, and conventional methods to achieve smooth surfaces for film formation are time-consuming and inefficient.
Innovation Solution
Control the surface roughness of the base material by managing the average length RSm and root mean square slope Rdq instead of solely focusing on arithmetic average roughness Ra, ensuring the surface has an average length RSm of 70 μm or more, which enhances the protective film's durability and particle resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the protective film thickness is reduced to improve productivity and reduce treatment time, then the film formation time is shortened and productivity is improved, but the surface shape of the protective film is more strongly affected by the base material surface shape, leading to increased surface roughness and potential particle formation
Solution Approach 1:
The invention changes the parameter for evaluating base material surface roughness from arithmetic average roughness Ra to average profile element length RSm. By controlling RSm to be 70 μm or more, the invention enables formation of protective films with excellent particle proof properties even when Ra is relatively high (0.2 μm or more), thus allowing thinner films to be formed without compromising surface quality
Solution Approach 2:
The invention focuses on controlling the planar characteristics (average profile element length RSm) of the base material surface rather than the height characteristics (Ra). This local quality approach targets the specific parameter that most influences protective film surface smoothness, allowing optimization of film formation on thinner films without requiring excessive surface preparation
2Manufacturing precision
If conventional surface treatment methods are used to achieve smooth surfaces with Ra of 0.1 μm or less, then the protective film surface smoothness is improved and particle formation is reduced, but the surface treatment time and production cost increase
Solution Approach 1:
The invention fundamentally changes the surface roughness evaluation parameter from Ra (arithmetic average roughness) to RSm (average profile element length). This parameter change allows acceptance of base material surfaces with higher Ra values (0.2 μm or more) as long as RSm is 70 μm or more, thereby eliminating the need for extensive surface treatment to achieve Ra ≤ 0.1 μm while still obtaining protective films with excellent particle proof properties
Solution Approach 2:
Instead of trying to reduce Ra to very low values through extensive surface treatment, the invention inverts the approach by controlling RSm to be sufficiently large (70 μm or more). This inversion allows much faster and simpler surface treatment processes while achieving the same or better protective film quality in terms of particle prevention
3Productivity
If the base material surface has high arithmetic average roughness Ra, then the surface treatment process is simplified and productivity is improved, but the protective film surface becomes uneven and particles are more likely to form
Solution Approach 1:
The invention changes the controlling parameter for base material surface roughness from Ra to RSm. By setting RSm ≥ 70 μm, the invention enables use of base material surfaces with higher Ra values that can be processed more quickly and cheaply, while still preventing particle formation on the protective film. The key insight is that RSm, not Ra, is the critical parameter for preventing protective film surface unevenness and particle formation
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 structural member achieves excellent particle proof by preventing film peeling and maintaining film density, even with surfaces exceeding 0.1 μm arithmetic average roughness Ra, thereby improving productivity and reducing surface treatment time.
Implementation Method 1
a protective film covering a surface of the base material
Implementation Method 2
a surface roughness of the base material is a roughness with an average length RSm of 70 μm or more
Data Source
AI summary
A structural member 10 has a base material 100 and a protective film 200 covering the surface S1 of the base material 100. A roughness of the surface S1 of the base material 100 is a roughness with an average length RSm of 70 μm or more.