Plasma Chamber Voltage Control for Etch Uniformity
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Solution Overview
Problem
Semiconductor manufacturing processes, such as dry-etching, face challenges with aspect ratio dependence etch (ARDE) phenomena, where etch depth varies with pattern width due to inconsistent plasma conditions.
Innovation Solution
A semiconductor manufacturing device with a plasma chamber that alternates between two distinct plasma conditions by adjusting source and bias power voltages and frequencies, using matching circuits to control impedance and minimize reflected power, allowing for precise control of plasma formation and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma conditions are maintained continuously for etching processes, then etching speed is improved, but aspect ratio dependence etch (ARDE) phenomenon occurs causing non-uniform etching across different pattern widths
Solution Approach 1:
The patent applies periodic pulsed plasma mode alternating with non-plasma mode to the etching process. During pulsed plasma mode, etching reactions occur; during non-plasma mode, passivation reactions occur without etching. This periodic alternation prevents ARDE phenomenon by allowing uniform passivation across all pattern widths, achieving both high etching speed and uniform etching depth across different pattern widths.
Solution Approach 2:
The patent changes plasma parameters by switching between different gas flow rates for etching gas and passivation gas. During etching phase, etching gas flow rate is increased; during passivation phase, passivation gas flow rate is increased. This parameter variation enables control over the etching process to achieve uniform results across different pattern geometries while maintaining high productivity.
2Productivity
If high power is applied to maintain plasma for deposition processes, then deposition rate is improved, but plasma uniformity deteriorates leading to non-uniform film quality
Solution Approach 1:
The patent employs periodic alternation between high-power plasma mode for deposition and lower-power or non-plasma mode for uniformity maintenance. This periodic action allows high deposition rates during plasma phases while ensuring film uniformity during non-plasma or low-power phases, resolving the contradiction between productivity and film quality.
Solution Approach 2:
The patent applies preliminary passivation treatment before deposition to ensure uniform surface conditions. By preparing the substrate surface uniformly beforehand through controlled passivation, the subsequent deposition process can proceed at high rates while maintaining film uniformity, as the preliminary action has already established consistent starting conditions across the substrate.
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 improves the uniformity of pattern etching and deposition processes by maintaining consistent plasma conditions, reducing reflected power and enhancing the efficiency of semiconductor manufacturing.
Implementation Method 1
a plasma chamber to receive a gas mixture containing a first gas and a second gas different from each other; a source power supply to apply a source voltage of a first level to the plasma chamber at a first time and a source voltage of a second level different from the first level to the plasma chamber at a second time
Data Source
AI summary
A semiconductor manufacturing device includes a plasma chamber, a source power supply, and first and second bias power supplies. The source power supply applies a first source voltage to the plasma chamber at a first time and a second source voltage to the plasma chamber at a second time. The first bias power supply applies a first turn-on voltage to the plasma chamber at the first time and a first turn-off voltage to the plasma chamber at the second time. The second bias power supply applies a second turn-off voltage to the plasma chamber at the first time and a second turn-on voltage to the plasma chamber at the second time. The plasma chamber forms plasmas of different conditions from a gas mixture in the plasma chamber based on the source, turn-on, and turn-off voltages.