Glass Substrate Flattening via Multi-Rate Etching
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Solution Overview
Problem
Conventional methods for flattening glass substrates with concave portions fail to achieve high surface flatness due to the removal of surface layers during etching, leading to incomplete flattening.
Innovation Solution
A method involving multiple etching processes with etching liquids of varying rates, where the first etching liquid has a slow rate to remove concave portions and the second etching liquid has a faster rate to further flatten the surface, along with the use of inactive liquids and inorganic oxo acid additives to suppress growth and visibility of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If etching is first carried out with the etching liquid at the fast etching rate, then the etching process is efficient and removes material quickly, but the concave portions grow larger and flatness of the surface is not improved sufficiently
Solution Approach 1:
The etching process is divided into multiple sequential steps using different etching liquids with different etching rates. The first step uses a fast etching rate liquid to remove material efficiently, while subsequent steps use slower etching rate liquids to refine the surface and eliminate concave portions. This segmentation allows each step to optimize for its specific function, resolving the contradiction between efficiency and precision.
Solution Approach 2:
The fast etching rate liquid is applied first to perform preliminary material removal before the slower etching rate liquids are applied. This preliminary action efficiently removes the bulk material while the subsequent slower etching steps then address the surface quality issues, ensuring that the concave portions are eliminated after the main etching is complete.
2Productivity
If etching is carried out with the etching liquid at the fast etching rate, then material is removed quickly, but concave portions such as very small flaws are removed together with the surface layer leading to incomplete flattening
Solution Approach 1:
The etching process is segmented into multiple steps with different etching liquids. The first step with fast etching rate removes material efficiently including flaws, while subsequent steps with slower etching rates specifically target and eliminate the concave portions created by flaw removal, ensuring complete flattening without sacrificing productivity.
Solution Approach 2:
The etching rate parameter is changed between steps by using different etching liquids. The first step uses a high etching rate for efficient material removal, while subsequent steps use lower etching rates to provide the controlled, gradual removal needed to eliminate concave portions and achieve complete flattening.
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 results in significantly improved surface flatness, suppressing the growth of concave portions and reducing the formation of visible dimples, achieving a more even surface compared to conventional methods.
Implementation Method 1
a method which includes preparing two kinds of etching liquids different from each other in an etching rate for the glass substrate, first etching the substrate with the etching liquid at a fast etching rate, and then with the etching liquid at a slow etching rate, thereby flattening a surface of the glass substrate
Data Source
AI summary
A method for flattening a glass substrate includes the steps of preparing plural kinds of etching liquids different from one another in an etching rate, preparing the glass substrate, and etching the glass substrate at least one time with each of the etching liquids and executing the etching a plurality of times in total. When the etchings are executed the plurality of times, an etching rate of the glass substrate with one etching liquid used for one etching of plural etchings is slower than that of the glass substrate with the another etching liquid used for another etching executed after the one etching process of the plural etching processes.