Chemical Planarization of Silicon Dioxide Films
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Solution Overview
Problem
Current chemical mechanical planarization (CMP) methods for silicon dioxide films in semiconductor manufacturing face challenges such as scratches from abrasive grains, inefficient processing due to non-selective etching, and limitations in applying catalyst-referred etching methods, which hinder achieving high planarity and minimizing damage.
Innovation Solution
A method using a hydrosilicofluoric acid aqueous solution with silicon dioxide at saturated concentration, where the equilibrium state of the treatment liquid is manipulated to selectively dissolve convex portions of silicon dioxide films, either by temperature control, hydrofluoric acid exudation, fluorine ion generation, or electrochemical means, without abrasive grains, to achieve planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical mechanical planarization (CMP) method is used for planarizing silicon dioxide film, then planarization can be achieved, but polishing damage (scratches) caused by abrasive grains occurs leading to yield reduction
Solution Approach 1:
The patent replaces the mechanical CMP process with a chemical planarization process using a treatment liquid containing hydrofluoric acid and silicon dioxide particles. The chemical etching action dissolves the silicon dioxide film uniformly without mechanical contact, eliminating scratches and polishing damage while achieving the required planarization precision.
Solution Approach 2:
The patent introduces silicon dioxide particles as an intermediary in the treatment liquid. These particles act as a buffering medium that controls the etching rate and promotes uniform planarization while preventing direct aggressive chemical attack that could cause damage. The particles are suspended in the hydrofluoric acid solution to mediate the planarization process.
2Productivity
If conventional etching methods are used, then silicon dioxide film can be removed, but dissolution rate is not uniform leading to inefficient planarization
Solution Approach 1:
The patent introduces silicon dioxide particles as an intermediary in the treatment liquid. These particles act as a buffering medium that controls the etching rate and promotes uniform planarization while preventing direct aggressive chemical attack that could cause damage. The particles are suspended in the hydrofluoric acid solution to mediate the planarization process.
Solution Approach 2:
The treatment liquid composition and conditions are optimized to create locally adaptive etching behavior. The silicon dioxide particles distribute uniformly across the surface, providing localized control over the etching process. This ensures that both convex and concave areas receive appropriate treatment rates, achieving uniform dissolution across the entire film surface.
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 reduces the height of irregularities on silicon dioxide films with high efficiency, minimizing scratches and achieving planarity suitable for advanced semiconductor devices while avoiding mechanical damage.
Implementation Method 1
dissolution rate of convex portions is made larger than dissolution rate of concave portion of the irregularity while changing equilibrium state of the treatment liquid
Implementation Method 2
generating precipitation of silicon dioxide on concave portions of the irregularity while bringing a treatment plate into contact with convex portions of the irregularity and changing relative positions
Data Source
AI summary
According to one embodiment, a method for chemical planarization includes: preparing a treatment liquid containing a hydrosilicofluoric acid aqueous solution containing silicon dioxide dissolved therein at a saturated concentration; and decreasing height of irregularity of a silicon dioxide film. In the decreasing, dissolution rate of convex portions is made larger than dissolution rate of concave portion of the irregularity while changing equilibrium state of the treatment liquid at areas being in contact with the convex portions of the irregularity, in a state in which the silicon dioxide film having the irregularity is brought into contact with the treatment liquid.