Aluminum Foil Surface Roughness Control for Roll-to-Roll Wrinkling
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Solution Overview
Problem
Conventional aluminum foils exhibit wrinkling or waviness during the roll-to-roll process due to high surface roughness and uneven contact resistance, which affects the smoothness and yield of electronic device production.
Innovation Solution
The aluminum foil is produced with surface roughness Ra not exceeding 10 nm and Rz not exceeding 40 nm, along with a minimum of 10 peak counts per 40 µm reference length, and friction coefficients of 1.0 or less, ensuring uniform contact and reduced tension during rolling, thereby suppressing wrinkling and waviness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aluminum foil with higher surface roughness is used, then manufacturing is easier and friction is higher, but wrinkling and waviness occur during roll-to-roll process
Solution Approach 1:
The invention changes the surface roughness parameters of the aluminum foil by controlling Ra to 10 nm or less and Rz to 40 nm or less through specific rolling processes. This parameter change reduces the friction between the foil and rollers during the roll-to-roll process, preventing wrinkling and waviness while maintaining manufacturing feasibility.
Solution Approach 2:
The invention performs preliminary surface treatment during the rolling process itself, rather than requiring post-manufacturing polishing. By controlling the rolling conditions and using appropriately treated rollers, the desired surface roughness is achieved during production, which then prevents wrinkling in subsequent roll-to-roll processes.
2Manufacturing precision
If surface roughness Ra is reduced to 10 nm or less, then uniform contact is achieved, but manufacturing complexity increases
Solution Approach 1:
The invention achieves Ra ≤ 10 nm by carefully controlling rolling parameters such as rolling force, roller speed, and roller surface condition. These parameter changes enable precise surface smoothness control while using standard rolling equipment, avoiding the need for complex post-processing apparatus.
3Weight of moving object
If thin substrate is used to reduce thickness and weight, then electronic device requirements are met, but wrinkling susceptibility increases
Solution Approach 1:
The invention changes the surface roughness parameters of thin aluminum foil (Ra ≤ 10 nm, Rz ≤ 40 nm) to reduce friction during handling and processing. This enables thin foils to maintain sufficient mechanical stability and resistance to wrinkling during roll-to-roll processes despite their reduced thickness and weight.
Data Source
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AI summary
An aluminum foil includes a first main surface (1A) and a second main surface (1B) located opposite to the first main surface (1A). In at least one of the first main surface (1A) and the second main surface (1B), a surface roughness Ra is not more than 10 nm, a surface roughness Rz is not more than 40 nm in each of a rolling direction (X) and a direction (Y) perpendicular to the rolling direction (X), and the number of peak counts is not less than 10 when a reference length (L) is 40 µm, the number of peak counts being determined from a roughness curve in at least one of the rolling direction (X) and the direction (Y) perpendicular to the rolling direction (X).