Multi-Layer Etch Stop Structure for Copper Hillock Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable copper-based interconnect structures due to issues like copper pits and hillocks, which lead to yield loss and reduced performance, particularly in multilayer interconnect features as IC feature sizes shrink.
Innovation Solution
A method is introduced that involves forming a multi-layer etch stop structure using specific dielectric layers, such as a metal-containing oxynitride layer, a silicon-containing layer, and a metal-containing oxide layer, to protect copper features from hydrogen diffusion and hillock formation, thereby enhancing the reliability of interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-based interconnect structures are formed in multilayer interconnect features, then interconnect functionality is achieved, but copper pits and hillocks occur leading to yield loss
Solution Approach 1:
A multi-layer etch stop structure is introduced as an intermediary between the copper interconnect and the overlying dielectric layers. This etch stop structure includes a first etch stop layer and a second etch stop layer that act as protective barriers, preventing hydrogen diffusion to the copper features and thereby preventing copper pit and hillock formation while maintaining interconnect functionality.
Solution Approach 2:
The etch stop structure is formed in advance before subsequent processing steps that could generate hydrogen. By establishing this protective barrier beforehand, the copper interconnect features are pre-protected from hydrogen diffusion that would otherwise occur during later fabrication processes, preventing defect formation before it can happen.
2Productivity
If feature size is reduced to increase functional density, then production efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The etch stop structure is segmented into multiple distinct layers (first etch stop layer and second etch stop layer) with different material compositions and etching characteristics. This segmentation allows each layer to serve specific functions: the first layer provides primary hydrogen barrier protection while the second layer facilitates selective etching processes. The segmented structure manages complexity by dividing the protective function into specialized sub-functions that can be independently optimized.
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
The multi-layer etch stop structure effectively reduces copper pit formation and hillock occurrence, improving the reliability and yield of interconnect structures, and maintaining device performance by preventing hydrogen-induced damage and controlling deposition temperatures.
Implementation Method 1
forming a multi-layer etch stop structure using specific dielectric layers, such as a metal-containing oxynitride layer, a silicon-containing layer, and a metal-containing oxide layer, to protect copper features from hydrogen diffusion
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a first diffusion barrier layer made of a dielectric material including a metal element, nitrogen, and oxygen and a first protection layer made of a dielectric material including silicon and oxygen and in direct contact with the top surface of the first diffusion barrier layer. The semiconductor device structure also includes a first thickening layer made of a dielectric material including the metal element and oxygen and in direct contact with the top surface of the first protection layer. A maximum metal content in the first thickening layer is greater than that in the first diffusion barrier layer. The semiconductor device structure further includes a conductive feature surrounded by and in direct contact with the first diffusion barrier layer, the first protection layer, and the first thickening layer.