Insulating Trench Sealing to Eliminate Central Cavities
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Solution Overview
Problem
Existing methods for manufacturing insulating trenches in electronic devices often result in central cavities left unfilled, leading to tightness issues due to incomplete deposition of insulating material, which can cause electrical or optical insulation failures.
Innovation Solution
A method involving chemical-mechanical polishing, followed by the deposition of an etch stop layer and additional insulating layers, with anisotropic etching and a waterproof sealing layer to fill and seal the cavities, ensuring the trench is tight and waterproof.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a trench is filled with insulating material using conventional deposition methods, then the trench structure is formed, but central cavities remain unfilled leading to tightness issues and insulation failures
Solution Approach 1:
A polishing step is performed before the final insulating material deposition to pre-fill central cavities in the trench structure. This preliminary action ensures that subsequent deposition steps can complete the trench filling without leaving voids, thereby improving both manufacturing precision and insulation reliability
Solution Approach 2:
The invention changes the physical state and surface properties of the trench structure through polishing, modifying the parameters of the substrate surface to enable complete material deposition. This parameter change from rough to smooth surface allows the insulating material to properly adhere and fill the trench without forming central cavities
2Reliability
If multiple deposition and etching steps are added to fill and seal cavities, then trench tightness and waterproofing are improved, but manufacturing process complexity increases
Solution Approach 1:
The polishing step serves multiple functions simultaneously: it prepares the surface for deposition, fills central cavities, and creates a uniform surface for subsequent layer deposition. This multi-functionality reduces the need for additional separate steps to address trench tightness and waterproofing, thereby improving reliability without proportionally increasing process complexity
Solution Approach 2:
The invention implements a nested structure where the polishing step is integrated into the existing deposition sequence, and subsequent etch stop layers and insulating layers are deposited in a nested manner within the trench structure. This nesting approach ensures tight sealing while maintaining process efficiency
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 method effectively fills and seals cavities, ensuring the insulating trench is tight and waterproof, preventing insulation failures and enhancing the reliability of electronic devices such as transistors and image sensors.
Implementation Method 1
step (f) of polishing of the surface of said substrate... step (f) implements a chemical-mechanical polishing method
Implementation Method 2
step (g). According to an embodiment, during step (g), the wet etching uses a hydrofluoric acid solution
Implementation Method 3
depositing a first etch stop layer on said first material... depositing a second layer of a second insulating material on said first etch stop layer... depositing a third layer made of a third tight material
Implementation Method 4
step (d) is an anisotropic etching step
Data Source
AI summary
The present description concerns a method of manufacturing an insulating trench in a substrate, for an electronic device, comprising the following successive steps: (a) filling a trench formed in the substrate with a first insulating material; (b) depositing a first etch stop layer on the first material; (c) depositing a second layer of a second insulating material on the first etch stop layer; (d) etching down to the etch stop layer; and (e) depositing a third layer made of a third tight material.