Sacrificial Layer Contact Formation for Semiconductor Gate Structures
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is forming reliable contacts between gate structures without damaging the capping patterns, which can lead to electrical shorts and reduced integration density due to the complexity of current etching processes.
Innovation Solution
A method involving a sacrificial layer with high etch selectivity relative to the capping pattern, using a gas containing oxygen, nitrogen, and hydrogen for dry etching, and subsequent oxidation or UV treatments to form self-aligned contacts without opening issues, while maintaining the integrity of the capping pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching processes are used to form contacts, then contact formation is achieved, but the capping patterns are damaged leading to electrical shorts
Solution Approach 1:
A sacrificial layer is formed over the gate structure before contact hole formation. This sacrificial layer protects the capping pattern during subsequent etching processes. The sacrificial layer is selectively removed after contact formation to complete the contact holes, preventing damage to the capping pattern while enabling reliable contact formation.
Solution Approach 2:
The sacrificial layer acts as an intermediary protective element between the etching process and the capping pattern. It absorbs the harmful effects of the etching process, allowing contact holes to be formed without damaging the underlying capping pattern, thus resolving the contradiction between contact formation and capping pattern integrity.
2Reliability
If complex etching processes are used to form contacts, then contact formation is achieved, but integration density is reduced due to process complexity
Solution Approach 1:
The sacrificial layer is formed in advance to enable simpler contact hole etching processes. By having the sacrificial layer in place before etching, the process requires fewer steps and lower complexity compared to conventional methods that need multiple etching stages and precise control to avoid capping pattern damage.
Solution Approach 2:
The invention changes the etching selectivity parameters by introducing the sacrificial layer with specific etch rate characteristics. This allows for simpler etching conditions and processes while maintaining contact formation quality, reducing overall process complexity.
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 approach enables the formation of reliable contacts without damaging the capping patterns, reducing the occurrence of electrical shorts and enhancing integration density by using a sacrificial layer with high etch selectivity and specific etching processes.
Implementation Method 1
The sacrificial layer may be removed using an oxidation treatment
Implementation Method 2
The sacrificial layer may be removed using an oxidation treatment, an ozone treatment, an ultraviolet (UV) treatment
Implementation Method 3
The first opening may be formed by a dry etching process using a gas containing oxygen, nitrogen, and hydrogen
Data Source
AI summary
A sacrificial layer is formed to cover the gate structures. The sacrificial layer is patterned to form a first opening in the sacrificial layer. A preliminary contact is formed in the first opening and the sacrificial layer is selectively removed. An insulating layer is formed to cover the gate structures and to expose the preliminary contact. The preliminary contact is removed to form a second opening in the insulating layer, and then a contact is formed in the second opening.