Flowable Oxide Gap Fill Using Pulsed Vacuum UV Conversion
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Solution Overview
Problem
Existing methods for filling gaps in microelectronics manufacturing, such as PECVD and PEALD, face challenges like seam formation, high thermal budgets, and non-uniform film conversion, particularly when using flowable dielectric films.
Innovation Solution
A method involving the formation of a flowable silicon nitride film using a silicon-containing gas and a nitrogen-containing gas, followed by conversion to a silicon oxide film using Vacuum UV radiation, which is applied in a pulsed mode with a duty ratio of 20% or less, at an intensity of 80 mW/cm2 to 120 mW/cm2, and at temperatures between 70°C and 150°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing is used to harden the flowable film, then the film conversion is complete, but the thermal budget becomes excessively high
Solution Approach 1:
The patent replaces the thermal field (high temperature annealing) with a photochemical field (Vacuum UV radiation at 172nm). The VUV radiation directly breaks chemical bonds and initiates crosslinking reactions in the flowable film, achieving complete conversion and hardening without requiring high temperatures, thus resolving the contradiction between conversion completeness and thermal budget control
Solution Approach 2:
The patent changes the hardening mechanism from thermal activation to photochemical activation. By using VUV radiation with specific wavelength (172nm) and controlling irradiation dose, the film can be completely converted at low temperatures, transforming the process parameter from temperature-dependent to radiation-dose-dependent
2Reliability
If UV radiation in steam atmosphere is used to harden the film, then the film surface is hardened, but the conversion is not uniform through the depth
Solution Approach 1:
The patent replaces conventional UV radiation with Vacuum UV radiation at 172nm. The shorter wavelength VUV photons have higher energy and can penetrate and activate molecules throughout the film depth more effectively, enabling uniform crosslinking and conversion from the bulk rather than just the surface, thus resolving the non-uniform conversion problem
Solution Approach 2:
The patent employs pulsed VUV irradiation with a duty cycle of 10% or less. This periodic action allows the film to uniformly absorb radiation energy and react throughout its depth, preventing surface-only hardening and achieving consistent conversion uniformity across the entire film thickness
3Reliability
If conventional UV radiation is used for film hardening, then the film surface is treated, but the processing time becomes excessively long
Solution Approach 1:
The patent substitutes conventional UV radiation with VUV radiation at 172nm. The higher energy VUV photons induce much faster photochemical reactions and crosslinking rates, reducing the required irradiation time from minutes to seconds, thereby dramatically decreasing the loss of time while maintaining complete film hardening
Solution Approach 2:
The patent uses intense pulsed VUV radiation to rapidly complete the film conversion process. The high power density and short wavelength enable the hardening reaction to proceed extremely quickly, rushing through the curing process in a matter of seconds rather than prolonged exposure times
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 method enables rapid and uniform hardening of the flowable film by depth at low temperatures, reducing processing time and avoiding thermal budget issues while ensuring uniform film properties.
Implementation Method 1
converting the silicon nitride film into the silicon oxide film in which a Vacuum UV radiation may be applied while supplying the oxygen-containing gas
Implementation Method 2
applying a power to the reaction chamber and activating the nitrogen-containing gas
Data Source
AI summary
Provided is a method of filling a gap with a flowable oxide film. In one embodiment of the disclosure, the method comprises forming a flowable silicon nitride film, followed by converting the silicon nitride film in a silicon oxide film. The silicon nitride film may be formed by supplying an oligomeric silicon source and a nitrogen source activated by a power. The silicon nitride film may be converted into the silicon oxide film by supplying an oxygen source while applying a vacuum UV radiation. The vacuum UV radiation may be applied in a pulsed mode.