UV Treatment of Etch Stop Films for Selectivity
Solution Overview
Problem
Current etch stop films and hard mask layers in semiconductor manufacturing face challenges in achieving high selectivity and hermeticity, which are crucial for improving device performance and reliability, as they are prone to etching faster than dielectric layers and susceptible to moisture penetration, leading to increased dielectric constant and reliability issues.
Innovation Solution
The method involves ultra-violet (UV) treatment of etch stop and hard mask films to remove hydrogen, cross-link, and increase density, which can be done directly or through another dielectric layer, and may be concurrent with thermal energy treatment, specifically applicable in damascene processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the etch stop film thickness is increased to improve selectivity, then etching resistance is improved, but the dielectric constant increases and RC benefits are degraded
Solution Approach 1:
The patent applies UV irradiation to change the physical and chemical parameters of the etch stop film, specifically increasing cross-linking density and reducing hydrogen content. This transforms the film's etching characteristics without changing its thickness, allowing thin films to achieve high selectivity. The UV treatment modifies the film's molecular structure to be more resistant to etching while maintaining the low-k properties of the dielectric layer.
2Reliability
If the etch stop film thickness is increased to improve selectivity, then etching resistance is improved, but material usage and manufacturing cost increase
Solution Approach 1:
UV irradiation fundamentally changes the film's properties by increasing cross-linking and reducing hydrogen, making thin films as effective as thick films for etch stopping. This eliminates the need to deposit additional material, reducing both material costs and deposition time while achieving the required selectivity.
3Device complexity
If conventional etch stop films are used without UV treatment, then processing is simpler, but hermeticity against moisture penetration is poor
Solution Approach 1:
UV irradiation modifies the molecular structure of the etch stop film by removing hydrogen and increasing cross-linking density, which closes voids and creates a more hermetic barrier. This single treatment step significantly improves moisture barrier properties without adding complex processing equipment or multiple deposition steps.
4Ease of manufacture
If hydrogen content in the etch stop film is high, then deposition is easier, but etch selectivity and hermeticity are reduced
Solution Approach 1:
The patent performs UV irradiation as a preliminary treatment to the etch stop film after deposition but before etching. This removes hydrogen and increases cross-linking in advance, preparing the film for high-selectivity etching. The deposition process remains simple, but the subsequent UV treatment transforms the film's properties to achieve the required performance.
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 enhances the selectivity and hermeticity of etch stop and hard mask films, allowing for thinner films that maintain low dielectric constant benefits, reduce manufacturing costs, and improve device reliability by preventing moisture penetration and adhesion issues.
Implementation Method 1
UV treatment of etch stop and hard mask films to increase etch selectivity and hermeticity by removing hydrogen
Implementation Method 2
cross-linking the film
Data Source
AI summary
A method for the ultraviolet (UV) treatment of etch stop and hard mask film increases etch selectivity and hermeticity by removing hydrogen, cross-linking, and increasing density. The method is particularly applicable in the context of damascene processing. A method provides for forming a semiconductor device by depositing an etch stop film or a hard mask film on a substrate and exposing the film to UV radiation and optionally thermal energy. The UV exposure may be direct or through another dielectric layer.