Semiconductor Gap Etching with Oxide Interlayer
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Solution Overview
Problem
Traditional damascene gap structures often result in undesirable profiles due to differing etch rates of dielectric regions, leading to residue dielectric material within the gap.
Innovation Solution
Incorporating an oxide region within the gap to facilitate a uniform etch rate between the bottom and wall etch rates, allowing for efficient removal of low-k dielectric material and reducing residue, while also providing structural support for metal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional etching is used to form a gap in the dielectric region, then the gap structure is formed, but the different etch rates (bottom etch rate vs wall etch rate) result in residue dielectric within the gap and an undesirable profile
Solution Approach 1:
The patent introduces an oxide region specifically within the gap area, creating a localized modification to the dielectric structure. This oxide region has different etching characteristics than the surrounding low-k dielectric material, enabling selective removal of dielectric material from the gap bottom while preserving the walls, thereby resolving the etch rate mismatch problem and eliminating residue dielectric
Solution Approach 2:
The oxide region acts as an intermediary layer between the top and bottom surfaces of the gap. During etching, this intermediate oxide layer facilitates differential etching by being more susceptible to removal at the gap bottom, allowing the etch front to progress uniformly and prevent dielectric residue accumulation
Data Source
AI summary
One or more techniques or systems for forming a semiconductor structure having a gap are provided herein. In some embodiments, a gap is formed between a first etch stop layer (ESL) and an ESL seal region. For example, the gap is formed by removing a portion of a low-k (LK) dielectric region above an oxide region and removing the oxide region. In some embodiments, the oxide region below the LK dielectric region facilitates removal of the LK dielectric region, at least because the oxide region enhances a bottom etch rate of a bottom of the LK dielectric region such that the bottom etch rate is similar to a wall etch rate of a wall of the LK dielectric region.