Glass Substrate Through Hole Uniformity via Two-Stage Etching
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Solution Overview
Problem
Conventional methods for manufacturing glass substrates with through holes often result in a narrow portion at the center of the hole due to insufficient etching solution diffusion and reaction product accumulation, especially when the initial hole diameter is small compared to the substrate thickness, leading to incomplete enlargement and a 'sandglass' shape.
Innovation Solution
A method involving two etching processes: a first etching process with a slower etching solution to form an initial through hole with a specific diameter ratio, followed by a second etching process using a faster etching solution to enlarge the hole further, ensuring uniform enlargement and minimizing narrow portion formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single wet etching process is performed to enlarge a fine through hole, then the etching solution cannot diffuse sufficiently and reaction products accumulate, but if the hole diameter is increased initially, then the aspect ratio increases and etching efficiency decreases
Solution Approach 1:
The single etching process is divided into two sequential etching processes. The first etching process uses a first etching solution to perform initial enlargement, and the second etching process uses a second etching solution with different properties to complete the enlargement. This segmentation allows each process to be optimized for different stages, improving overall etching uniformity while maintaining efficiency.
Solution Approach 2:
The patent changes the parameters of the etching solution between two processes. The first etching solution has specific properties optimized for initial etching, while the second etching solution has different properties (such as different concentration, composition, or temperature) optimized for final enlargement. This parameter change enables better control over etching rate and uniformity at different stages.
2Ease of manufacture
If laser irradiation forms a small diameter through hole, then the aspect ratio d/Rt becomes large making etching difficult, but if the hole diameter is larger, then etching is easier but the through hole does not achieve the desired fine dimensions
Solution Approach 1:
The laser irradiation step creates an initial hole with controlled small diameter that serves as a starting point for subsequent etching. This preliminary action establishes the precise final diameter requirement while creating a hole large enough to allow etching solution penetration, thus preparing the substrate for effective two-stage etching.
Solution Approach 2:
The patent employs continuous useful action by performing two sequential etching processes without interrupting the overall enlargement objective. The first etching process begins the enlargement, and the second etching process continues and completes it, ensuring continuous progress toward the desired through hole dimensions while maintaining etching efficiency throughout.
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 the generation of narrow portions and achieves a through hole with a desired shape, enhancing the manufacturing process by ensuring uniform etching and complete hole enlargement without residual reaction products.
Implementation Method 1
forming an initial hole in a glass substrate by irradiating laser light from a first surface side of the glass substrate
Implementation Method 2
performing a first etching process on the glass substrate using a first etching solution to form, from the initial hole, a first through hole
Implementation Method 3
performing a second etching process on the glass substrate to enlarge the first through hole using a second etching solution, whose etching rate with respect to the glass substrate is faster than an etching rate of the first etching solution
Data Source
AI summary
A method of manufacturing a glass substrate that has a through hole, includes (1) forming an initial hole in a glass substrate by irradiating laser light from a first surface side of the glass substrate; (2) performing a first etching process using a first etching solution to form, from the initial hole, a first through hole that extends from a first opening formed at a first surface to a second opening formed at a second surface, and to make a ratio “d1/Rt1” of a thickness “d1” of the glass substrate with respect to a diameter “Rt1” of the first opening to be within a range between 10 to 20; and (3) performing a second etching process to enlarge the first through hole using a second etching solution, whose etching rate with respect to the glass substrate is faster than that of the first etching solution.