Semiconductor Interconnection Alignment via Dielectric Segmentation
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Solution Overview
Problem
Conventional copper interconnection structures in semiconductor manufacturing face issues with alignment errors during photolithography, leading to short-circuits between neighboring conductive layers due to misalignment of openings and conductive materials, which affect the performance and reliability of the interconnections.
Innovation Solution
A method involving the formation of a semiconductor structure with a first dielectric layer containing conductive layers, where the top surface of each conductive layer is leveled with the dielectric layer, and subsequent dielectric layers are formed to create openings that expose adjacent conductive layers, allowing for precise placement of second conductive layers without damaging the initial dielectric layer, thereby improving electrical isolation and connection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography alignment methods are used, then the fabrication process is simple, but alignment errors cause short-circuits between neighboring conductive layers
Solution Approach 1:
The patent applies preliminary action by pre-forming the first dielectric layer with conductive layers embedded therein, and pre-leveling their top surfaces before the actual interconnection formation. This preliminary structuring establishes precise reference planes that guide subsequent opening formation and conductive layer deposition, ensuring accurate alignment without relying solely on photolithography alignment. The pre-established dielectric structure acts as a template that prevents short-circuits between adjacent conductive layers.
Solution Approach 2:
The patent introduces dielectric layers as intermediary structures between conductive layers. These dielectric layers serve as both electrical insulators and alignment reference structures. By forming openings through the dielectric layers and using them as intermediaries to deposit second conductive layers, the process achieves precise alignment while maintaining electrical isolation. The dielectric intermediaries buffer and reference the positions of adjacent conductive layers, preventing direct contact and potential short-circuits.
2Reliability
If openings are formed to expose conductive layers for interconnection, then electrical connection is achieved, but misalignment causes short-circuits between adjacent conductive layers
Solution Approach 1:
The patent segments the interconnection structure into multiple isolated components: first conductive layers embedded in first dielectric layers, second conductive layers formed in openings, and dielectric layers positioned between adjacent conductive layers. This segmentation creates physical and electrical isolation between adjacent conductive layers, preventing short-circuits while maintaining reliable electrical connections through the intended interconnection paths. Each segment is independently formed and positioned, ensuring controlled electrical contact only where intended.
Solution Approach 2:
Dielectric layers are introduced as intermediary structures between adjacent conductive layers to prevent harmful electrical contact. These intermediaries are strategically positioned to fill gaps and provide electrical isolation while allowing intended electrical connections to be formed through controlled openings. The dielectric intermediaries act as protective barriers that eliminate short-circuit risks between neighboring conductive layers.
3Reliability
If multiple dielectric and conductive layers are formed, then electrical isolation is improved, but the fabrication process becomes more complex
Solution Approach 1:
The patent merges multiple functions into integrated structures: dielectric layers simultaneously provide electrical isolation and serve as alignment reference structures for subsequent opening formation. Conductive layers are embedded within dielectric layers, combining structural support and electrical interconnection functions. This merging reduces the need for separate alignment and isolation processes, simplifying the overall fabrication complexity while maintaining high electrical isolation quality.
Solution Approach 2:
The dielectric layers perform multiple functions: they provide electrical isolation between conductive layers, serve as structural support, act as alignment reference planes for opening formation, and function as masks during subsequent processing steps. This multi-functionality reduces the total number of separate process steps and structures needed, simplifying the fabrication process while achieving superior electrical isolation and alignment precision.
Data Source
AI summary
A semiconductor device and its fabrication method are provided. A first dielectric layer is provided to cover a substrate. The first dielectric layer contains a plurality of first conductive layers. A portion of each first conductive layer is removed to form a plurality of first openings in the first dielectric layer. A second dielectric layer is formed in each first opening. A third dielectric layer having second-openings are formed on the first dielectric layer and on the second dielectric layers. Each second-opening exposes at least two adjacent second dielectric layers. Second dielectric layers exposed by a first second-opening are removed to form third openings to expose corresponding first conductive layers. Second conductive layers are formed in the third opening and the second-openings including the first second-opening. Stable electrical interconnections with high quality electrical isolations can be provided.