Contact Hole Etching Using Photo-Sensitive Polyimide Masking
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Solution Overview
Problem
During the formation of contact holes and fuse holes in semiconductor devices, the conductive pads often suffer from corrosion or residue, leading to poor quality electric interconnections due to exposure to etchants and residues.
Innovation Solution
A method involving a dielectric layer with a conductive pad, where a first trench is formed with a wider width than a second trench, and a photo-sensitive polyimide is used to expose the conductive pad, reducing the overall exposure to etchants and minimizing corrosion by carefully controlling the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conductive pad is exposed to form the contact hole, then the electric interconnection quality is improved, but the conductive pad suffers from corrosion or residue
Solution Approach 1:
The patent applies preliminary action by forming a protective layer on the conductive pad before the contact hole etching process. This protective layer is deposited in advance to prevent corrosion and residue formation during subsequent etching operations, thereby protecting the pad while still allowing high-quality electrical interconnection.
Solution Approach 2:
The patent uses an intermediary substance (protective layer) that mediates between the etching process and the conductive pad. This intermediary layer allows the etching to proceed effectively for contact hole formation while simultaneously protecting the pad from harmful corrosion and residue, resolving the contradiction between exposure quality and pad damage.
2Ease of manufacture
If the contact hole and fuse hole are integrally formed, then the manufacturing process is simplified, but the conductive pad quality deteriorates due to prolonged etchant exposure
Solution Approach 1:
The protective layer is formed preliminarily on the conductive pad before the integral etching process begins. This preliminary protection enables the simplified integral formation of contact and fuse holes while preventing the quality deterioration that would otherwise result from prolonged etchant exposure.
Solution Approach 2:
The protective layer acts as an intermediary that allows the integral etching process to proceed without compromising pad quality. It mediates between the need for process simplification and the requirement for high pad quality, enabling both goals to be achieved simultaneously.
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 conductive pad corrosion and residue formation, ensuring better quality electric interconnections and reducing the risk of defects in semiconductor devices.
Implementation Method 1
a photo-sensitive polyimide is formed on the dielectric layer and extending into the first trench
Data Source
AI summary
A method of fabricating a contact hole and a fuse hole includes providing a dielectric layer. A conductive pad and a fuse are disposed within the dielectric layer. Then, a first mask is formed to cover the dielectric layer. Later, a first removing process is performed by taking the first mask as a mask to remove part the dielectric layer to form a first trench. The conductive pad is disposed directly under the first trench and does not expose through the first trench. Subsequently, the first mask is removed. After that, a second mask is formed to cover the dielectric layer. Then, a second removing process is performed to remove the dielectric layer directly under the first trench to form a contact hole and to remove the dielectric layer directly above the fuse by taking the second mask as a mask to form a fuse hole.