Circuit Substrate Contact Hole Insulating Layer Etching
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Solution Overview
Problem
In active matrix type panels, the separation etching of inorganic and resin insulating layers during contact hole formation can lead to stair-like steps, causing disconnection issues in the pixel electrode and conductive layers.
Innovation Solution
A circuit substrate design where the side surfaces of the inorganic and resin insulating layers contact each other within the contact holes, allowing the conductive layers to extend along these surfaces, eliminating stair-like steps and reducing disconnection risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate etching processes are used for the first insulating layer and the second insulating layer to form contact holes, then the insulating layers can be selectively processed, but stair-like steps are generated at the boundary of the openings, causing stepped cuts in the pixel electrode
Solution Approach 1:
The patent merges the etching processes for the first and second insulating layers into a single simultaneous etching operation. By using a unified etching process with appropriately selected etching conditions and selectivity ratios, both insulating layers are etched at the same time to form contact holes that pass through both layers without generating stair-like steps at their boundaries. This eliminates the stepped cuts in the pixel electrode while maintaining the ability to selectively process different insulating layer materials.
2Reliability
If the pixel electrode is formed as a thin layer extending along the inner surface of the contact hole, then connection to the drain electrode is achieved, but stepped cuts occur at stair-like steps, causing disconnection
Solution Approach 1:
The patent applies preliminary anti-action by preventing the formation of stair-like steps in the first place through simultaneous etching of both insulating layers. By eliminating the root cause (stair-like steps at the boundary of openings) before the pixel electrode is formed, the thin pixel electrode can extend continuously along the inner surface of the contact hole without encountering stepped cuts that would cause disconnection. This proactive approach protects the electrode integrity rather than attempting to repair damage after formation.
3Adaptability or versatility
If conductive layers are formed in contact holes passing through multiple stacked layers, then device interconnection is achieved, but stepped cuts may occur at the side surface of the contact hole, causing disconnection
Solution Approach 1:
The patent merges the etching of multiple stacked insulating layers into a single simultaneous process, ensuring that all layers are etched to the same depth and alignment without creating stair-like steps at their boundaries. This unified approach allows conductive layers to be formed that continuously connect devices through the entire stack without encountering stepped cuts, maintaining both interconnection capability and reliability across multiple insulating layer interfaces.
Data Source
AI summary
A circuit substrate includes, on an insulating substrate, a plurality of devices, a plurality of conductive layers connected in one-to-one correspondence with the devices, and an insulating layer provided between the devices and the conductive layers. The insulating layer includes a first insulating layer covering the devices, a second insulating layer formed on the first insulating layer, and a plurality of contact holes each passing through the first and second insulating layers in a thickness direction thereof. Side surfaces of the first and second insulating layers contact each other in at least part of the inside of each contact hole. Each conductive layer extends along an upper surface of the second insulating layer, at least a part of a side surface of the contact hole in which the side surfaces of the first and second insulating layers contact each other, and a bottom surface of the contact hole.