Contact Hole Structure With Metal Buffer Layer
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Solution Overview
Problem
As integrated circuits (IC) become more complex and feature sizes shrink, existing interconnect technologies face challenges in forming high-density, reliable contact holes with precise dimensional accuracy for ultra-large-scale integration semiconductor devices.
Innovation Solution
A contact hole structure is developed, comprising a substrate, interlayer dielectric (ILD), a conductive layer, and an insulating capping layer with a spacer on the sidewall, where a metal-containing buffer layer protects the capping layer during etching, allowing precise control of the second opening's size and preventing damage, enabling smaller semiconductor device sizes and improved density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the insulating capping layer is directly etched to form the contact hole, then the etching process can proceed without additional protective layers, but the insulating capping layer suffers from etching damage that compromises dimensional accuracy and structural integrity
Solution Approach 1:
A metal-containing buffer layer is introduced as an intermediary protective layer between the etching environment and the insulating capping layer. This buffer layer absorbs etching damage while preserving the dimensional integrity of the underlying capping layer, enabling precise contact hole formation without compromising structural accuracy.
Solution Approach 2:
The metal-containing buffer layer is deposited in advance before the etching process to provide preemptive protection to the insulating capping layer. This preliminary protective action ensures that when etching subsequently occurs, the capping layer remains undamaged and maintains its precise dimensions for accurate contact hole definition.
2Productivity
If the feature sizes continue to shrink to increase device density, then the integration density improves, but the dimensional accuracy and reliability of contact holes become increasingly difficult to maintain
Solution Approach 1:
The metal-containing buffer layer serves as a protective intermediary that becomes increasingly important as feature sizes shrink. At smaller dimensions, the buffer layer's protective function is critical for maintaining the dimensional accuracy of contact holes, enabling continued scaling while preserving manufacturing precision through damage absorption during etching processes.
3Device complexity
If conventional interconnect technology is used without additional protective layers, then the fabrication process remains simple, but the contact hole structure lacks sufficient protection against etching damage and dimensional variations
Solution Approach 1:
The metal-containing buffer layer acts as a protective intermediary that significantly enhances contact hole structural reliability by shielding the insulating capping layer from etching damage. This additional layer provides a straightforward yet effective solution that improves reliability without introducing complex fabrication procedures.
Solution Approach 2:
The buffer layer provides beforehand cushioning protection to the insulating capping layer against etching damage. This prior protective measure ensures that the contact hole structure maintains its integrity and dimensional accuracy throughout the fabrication process, thereby improving reliability through preventive protection.
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 solution allows for precise control of the contact hole size, enhancing the density of semiconductor devices and interconnection structures by protecting the insulating capping layer from etching damage, thus improving the performance and reliability of ICs.
Implementation Method 1
a metal-containing buffer layer is formed to cover the insulating capping layer. After the portion of the metal-containing buffer layer disposed on the ILD is removed, a portion of the insulating capping layer disposed in the first opening is also removed
Data Source
AI summary
A contact hole structure includes a substrate, an interlayer dielectric (ILD), a conductive layer and an insulating capping layer. The ILD is disposed on the substrate and has a first opening. The conductive layer is disposed in the ILD and aligns the first opening. The insulating capping layer has a spacer disposed on a first sidewall of the first opening, wherein the spacer contacts to the conductive layer and defines a second opening in the first opening, so as to expose a portion of the conductive layer.