CMP Slurry Temperature Switching for Hydrophobic Layer Selectivity
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) processes face challenges in effectively planarizing layers on semiconductor substrates, particularly with hydrophobic layers, due to issues with polishing rate control, etch selectivity, and difficulty in removing the polishing slurry without damaging the substrate.
Innovation Solution
A CMP method using a thermoresponsive inhibitor, such as a polymer with a lower critical solution temperature (LCST), which adsorbs to the hydrophobic layer at a higher temperature to protect it during polishing and desorbs at a lower temperature for easy removal, combined with abrasive particles and deionized water, to enhance polishing control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional CMP slurry is used to polish hydrophobic layers, then polishing can be performed, but the polishing rate cannot be effectively controlled and etch selectivity is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the CMP slurry by incorporating a thermoresponsive polymer inhibitor that undergoes phase transition at specific temperatures. This polymer adsorbs onto the hydrophobic layer at polishing temperature to control etch selectivity, then desorbs at room temperature to enable easy slurry removal, thus simultaneously achieving controlled polishing selectivity and efficient slurry removal
Solution Approach 2:
The patent utilizes the phase transition property of thermoresponsive polymers (such as poly(N-isopropylacrylamide) with LCST around 32°C). The polymer transitions from a hydrated state at low temperature to a dehydrated state at high temperature, enabling it to adsorb onto the hydrophobic layer during polishing and desorb during slurry removal, thereby resolving the contradiction between maintaining polishing control and enabling easy removal
2Ease of operation
If the polishing slurry is removed at the same temperature as polishing, then removal can occur, but the slurry is difficult to remove without damaging the substrate
Solution Approach 1:
The patent changes the temperature parameter during slurry removal from polishing temperature to room temperature. This temperature change triggers the thermoresponsive polymer to desorb from the hydrophobic layer, converting the slurry from a strongly adhering state to a easily removable state, thus enabling easy slurry removal without substrate damage
Solution Approach 2:
The thermoresponsive polymer in the slurry automatically responds to temperature changes by undergoing phase transition and desorbing from the substrate. This self-responsive mechanism eliminates the need for harsh chemical cleaners or mechanical scrubbing, allowing the slurry to be easily removed by simple rinsing with deionized water at room temperature
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 method improves the quality and productivity of CMP by protecting the hydrophobic layer during polishing and facilitating easy slurry removal, reducing defects and increasing polishing selectivity.
Implementation Method 1
The thermoresponsive polymer may be adsorbed to the hydrophobic layer at the first temperature
Implementation Method 2
The thermoresponsive polymer may be adsorbed to the hydrophobic layer at the first temperature and desorbed from the hydrophobic layer at the second temperature
Implementation Method 3
The thermoresponsive polymer may be adsorbed to the hydrophobic layer at the first temperature and desorbed from the hydrophobic layer at the second temperature
Implementation Method 4
The chemical mechanical polishing slurry may include abrasive particles
Data Source
AI summary
A chemical mechanical polishing method may include polishing a polishing object at a first temperature using a chemical mechanical polishing slurry; and removing the chemical mechanical polishing slurry on the polishing object at a second temperature different from the first temperature. The chemical mechanical polishing slurry may include abrasive particles, a thermoresponsive inhibitor, and deionized water. The thermoresponsive inhibitor may include a thermoresponsive polymer exhibiting a phase-transition between the first temperature and the second temperature. The thermoresponsive polymer may be adsorbed to the hydrophobic layer at the first temperature and desorbed from the hydrophobic layer at the second temperature.