Dry Etching Electrode Shielding for Display Contact Holes
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Solution Overview
Problem
The existing methods for forming contact holes in insulating films during display manufacturing result in surface irregularities due to nonvolatile reaction products like aluminum fluoride, leading to imperfect coverage and wire breaking, as the aluminum electrodes react with fluorine-containing etching gases, causing deposition on the substrate and surrounding areas.
Innovation Solution
A dry etching method where an insulating material is used to cover the outer circumferential portion of the electrode, preventing exposure to plasma and scattering of aluminum components, allowing for a uniform etching operation by using a ceramic or plasma-resistant material like quartz or polyimide to create a stable environment, thereby avoiding the formation of irregularities and ensuring accurate etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aluminum alloy electrodes are used in dry etching, then cost is reduced and processability is improved, but nonvolatile reaction products are generated that cause surface irregularities
Solution Approach 1:
A shielding plate made of aluminum-resistant material (quartz, glass, or aluminum oxide) is introduced as an intermediary between the aluminum electrode and the fluorine-containing etching gas. This shielding plate prevents direct contact between the aluminum electrode and reactive fluorine species, blocking the formation of nonvolatile aluminum fluoride reaction products that cause surface irregularities, while still allowing the etching process to proceed effectively on the insulating film.
2Manufacturing precision
If electrode size is increased to improve etching uniformity, then etching uniformity is improved, but exposure to plasma causes more reaction product deposition
Solution Approach 1:
The shielding plate acts as a spatial separator that allows the electrode to maintain its larger size for uniform etching coverage while preventing the harmful interaction between the aluminum electrode surface and fluorine-containing plasma. The shielding plate blocks reactive species from reaching the electrode surface, eliminating the source of nonvolatile reaction products even when the electrode is fully exposed to plasma for uniform etching.
3Manufacturing precision
If fluorine-containing etching gas is used, then stable high-accuracy etching is achieved, but reaction with aluminum electrodes generates nonvolatile deposition
Solution Approach 1:
The shielding plate made of aluminum-resistant material serves as a physical barrier that prevents direct chemical interaction between the aluminum electrode and fluorine-containing etching gas. This allows the use of fluorine-containing gases (CF4, CHF3, C2F6, SF6) for stable and accurate etching of the insulating film without the electrode surface generating nonvolatile aluminum fluoride deposition.
Solution Approach 2:
The shielding plate creates a localized inert environment around the aluminum electrode by using materials that are chemically resistant to fluorine-containing plasma (quartz, glass, aluminum oxide). This inert barrier prevents the formation of reactive aluminum fluoride compounds while allowing the fluorine-containing etching gas to effectively etch the insulating film.
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 prevents the deposition of nonvolatile reaction products, maintains a uniform etching rate, and ensures high-quality, accurate etching operations, reducing the occurrence of rough surfaces and improving the formation of contact holes in insulating films.
Implementation Method 1
a voltage was applied between a pair of electrodes to generate an electric field therebetween, and plasma was thereby generated on an insulating substrate to be etched
Implementation Method 2
reactive ion etching operation
Implementation Method 3
an aluminum component of the electrode and fluorine contained in the etching gas react with each other. As a result, nonvolatile reaction product, such as nonvolatile aluminum fluoride is generated and deposited
Data Source
AI summary
A method of manufacturing displays, includes at least forming a metal pattern on a surface of an insulating substrate, forming an insulating film on the metal pattern, forming a pattern of a photosensitive resin on the insulating film, and forming a contact hole in the insulating film with the film of a photosensitive resin used as a mask. The forming a contact hole is a dry etching method in which an electric field is generated between a pair of opposed electrodes after an insulating substrate has been mounted on one electrode that includes aluminum in at least a surface thereof. The dry etching method includes forming a contact hole in the insulating film with an outer circumferential portion, which surrounds a region on which the insulating substrate is mounted, of the one electrode covered with an insulating material.