Electrostatic Chuck Step-Wise Voltage Control for Particle Reduction
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Solution Overview
Problem
During plasma processing, particles generated within the plasma processing chamber are deposited on substrates, leading to defects and reduced quality or yield, as existing methods fail to effectively minimize particle deposition.
Innovation Solution
Applying DC bias power to the electrostatic chuck in a step-wise manner to reduce current spikes and stabilize the wafer and chuck potential, thereby minimizing the transfer of negatively charged particles to the substrate, or charging the electrostatic chuck prior to plasma generation to prevent particle deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC bias power is applied to the electrostatic chuck to clamp the wafer, then the wafer clamping function is achieved, but current spikes occur which transfer negatively charged particles to the substrate causing defects
Solution Approach 1:
The electrostatic chuck is charged prior to plasma generation, before particles are formed in the plasma. This preliminary charging action establishes the electric field needed for wafer clamping before the harmful particles appear, preventing particle transfer to the substrate while maintaining reliable wafer clamping throughout the process
Solution Approach 2:
The patent applies DC bias power in a controlled, periodic manner rather than as a continuous spike. By regulating the timing and duration of power application, the system achieves wafer clamping while avoiding the conditions that cause particle transfer, thus resolving the contradiction between reliable clamping and preventing particle deposition
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
Significantly reduces particle deposition on substrates, as demonstrated by comparing conventional and innovative processes, resulting in improved plasma processing quality and yield.
Implementation Method 1
a voltage or charge is applied to a wafer support or electrostatic chuck in a manner which reduces particle deposits
Implementation Method 2
particles can be generated within the plasma processing chamber
Data Source
AI summary
A plasma processing method and apparatus are provided in which current spikes associated with application of a voltage to an electrostatic chuck (ESC) are minimized or reduced when the processing plasma is present. According to an example, the voltage is applied to the ESC after the processing plasma is struck, however the voltage is ramped or increased in a step-wise manner to achieve the desired final ESC voltage. In an alternate embodiment, the ESC voltage is at least partially applied before striking of the plasma for processing the wafer. By reducing current spikes associated with application of the voltage to the ESC during the presence of the processing plasma, transfer or deposition of particles on the wafer can be reduced.