Semiconductor Film Stack to Prevent Metal Layer Oxidation
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in suppressing oxidation of metal-element-containing films during the formation of low dielectric constant films, which can lead to film quality issues and increased dielectric constants.
Innovation Solution
A method involving a substrate processing apparatus where a conductive metal-element-containing film is treated with a reducing gas to remove native oxide layers, followed by forming a silicon nitride film without oxygen, and then a silicon oxycarbonitride film using specific gas sequences to control temperature and gas composition, preventing further oxidation and achieving a low dielectric constant laminated film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an oxidizing gas is supplied to form a low dielectric constant film on a heated substrate, then the dielectric constant is reduced, but the metal-element-containing film undergoes oxidation
Solution Approach 1:
A silicon-containing film is formed on the metal-element-containing film before the oxidizing gas is supplied. This preliminary film acts as a protective barrier that prevents oxygen from reaching and oxidizing the metal film during subsequent oxidation processes, while still allowing the formation of the low dielectric constant film structure
Solution Approach 2:
The silicon-containing film serves as an intermediary layer between the metal-element-containing film and the oxidizing environment. It mediates the interaction by providing oxygen barrier properties that protect the underlying metal film while permitting the overall film structure to achieve the desired low dielectric constant characteristics
2Productivity
If the substrate temperature is raised to form the low dielectric constant film, then the film formation is enhanced, but the oxidation rate of the metal film increases
Solution Approach 1:
The silicon-containing film is formed as a protective layer before high-temperature oxidation processes. This preliminary protective layer allows the substrate to be heated to temperatures that enhance low dielectric constant film formation without causing excessive oxidation of the metal film, as the silicon layer acts as a thermal and oxidative barrier
3Manufacturing precision
If a thick low dielectric constant film is formed, then the dielectric performance is improved, but the oxidation of the metal base is more severe
Solution Approach 1:
The silicon-containing film functions as a protective intermediary that enables the formation of thick low dielectric constant films. By placing this oxygen-barrier layer between the metal film and the oxidizing environment, the system can achieve the desired thick film structure for improved dielectric performance without suffering from severe metal film oxidation
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 effectively suppresses oxidation of the metal-element-containing films, reduces the dielectric constant of the laminated film, and improves film quality by blocking oxygen diffusion, suitable for applications in logic devices and memory devices.
Implementation Method 1
supplying a reducing gas to the substrate while raising a temperature of the substrate to a second temperature higher than the first temperature in the process chamber
Implementation Method 2
forming a first film, which contains silicon and at least one selected from the group of nitrogen and carbon and does not contain oxygen, on the metal-element-containing film, by supplying a first process gas, which does not include an oxidizing gas
Implementation Method 3
forming a second film, which contains silicon, oxygen, carbon, and nitrogen, on the first film such that the second film is thicker than the first film, by supplying a second process gas, which includes an oxidizing gas
Data Source
AI summary
There is included (a) loading a substrate where a conductive metal-element-containing film is exposed on a surface of the substrate into a process chamber under a first temperature; (b) supplying a reducing gas to the substrate while raising a temperature of the substrate to a second temperature higher than the first temperature in the process chamber; (c) forming a first film on the metal-element-containing film, by supplying a first process gas, which does not include an oxidizing gas, to the substrate under the second temperature in the process chamber; and (d) forming a second film on the first film such that the second film is thicker than the first film, by supplying a second process gas, which includes an oxidizing gas, to the substrate under a third temperature higher than the first temperature in the process chamber.