CMP Polishing Composition for Tungsten Corrosion Control
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Solution Overview
Problem
In the semiconductor manufacturing process, chemical mechanical polishing (CMP) techniques face challenges in achieving sufficient polishing rate and flatness while minimizing defects caused by corrosion of tungsten films, especially under low pH conditions.
Innovation Solution
A polishing composition for semiconductor processes is developed, incorporating a combination of amino azole-based and diazole-based corrosion inhibitors, along with a fluorine-based surfactant, to control the pH and inhibit corrosion of tungsten films. The composition includes polishing particles, such as colloidal silica, and is formulated to maintain a static etch rate of 6 Å/min or less for tungsten films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a low pH polishing composition is used to achieve high polishing rate, then polishing efficiency is improved, but corrosion of tungsten film increases
Solution Approach 1:
A corrosion inhibitor is introduced as an intermediary substance that mediates between the acidic polishing environment and the tungsten film. The inhibitor forms a protective layer on the tungsten surface, preventing direct contact between the acid and the metal, thus allowing high polishing rates to be maintained without excessive corrosion damage.
Solution Approach 2:
The pH of the polishing composition is adjusted to an optimized range (pH 2-5) rather than using extremely low pH values. This parameter optimization balances the polishing rate (which requires acidity) with the corrosion resistance (which suffers at very low pH), achieving both high productivity and reduced harmful effects.
2Manufacturing precision
If polishing is performed to achieve flatness and remove steps, then surface quality is improved, but dishing and erosion defects occur
Solution Approach 1:
The corrosion inhibitor acts as a protective intermediary that prevents the polishing particles and acidic environment from causing excessive erosion and dishing. By forming a protective film on the tungsten surface, it allows controlled material removal for flatness while preventing the harmful side effects of over-polishing.
Solution Approach 2:
The polishing composition parameters (pH, inhibitor concentration, particle size) are optimized to achieve selective removal of material at desired rates. The controlled chemistry enables sufficient polishing rate and flatness while minimizing dishing or erosion through precise parameter management.
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 polishing composition effectively inhibits corrosion of tungsten films under low pH conditions, while maintaining excellent polishing properties for silicon oxide films, thereby reducing defects and ensuring smooth surface polishing.
Implementation Method 1
a corrosion inhibitor, which includes a first corrosion inhibitor, which is an amino azole-based compound, and a second corrosion inhibitor, which is a diazole-based compound
Implementation Method 2
a substrate is pressed and rotated against a polishing pad while a slurry is applied to the pad to polish the surface
Implementation Method 3
The polishing composition for a semiconductor process may further include a fluorine-based surfactant
Data Source
AI summary
A polishing composition for a semiconductor process according to one embodiment of the present disclosure includes a polishing particle and a corrosion inhibitor. The corrosion inhibitor includes a first corrosion inhibitor, which is an amino azole-based compound and a second corrosion inhibitor, which is a diazole-based compound. The polishing composition for a semiconductor process has a pH of 2 to 5. A static etch rate for a tungsten film of the polishing composition for a semiconductor process is 6 Å/min or less. When polishing a substrate comprising a tungsten film and the silicon oxide film, such a polishing composition may provide a defect-reduced polished surface while exhibiting excellent polishing rate for a silicon oxide film.