Electrostatic Chuck Temperature Control for Plasma Etching Deposit Reduction
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Solution Overview
Problem
In plasma etching of silicon oxide or silicon nitride films, low temperatures lead to increased etching rates but result in the formation of unwanted carbon or carbon-fluorine plasma products that condense and form deposits on the target object and chamber walls, complicating post-etching processing.
Innovation Solution
A method involving a plasma processing apparatus with a temperature control system that sets the electrostatic chuck to −30°C or lower during etching, then raises the temperature to 0°C or higher immediately after etching to prevent deposit formation on the target object, thereby reducing post-etching contamination and facilitating faster chamber cleanup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the electrostatic chuck is set to be low (equal to or lower than −30° C.) during plasma etching, then the etching rate of the etching target film is increased, but plasma products containing carbon or carbon and fluorine are generated and condensed to form unwanted deposits on the target object
Solution Approach 1:
The temperature of the electrostatic chuck is dynamically changed in two stages: first maintained at low temperature (≤−30°C) during plasma etching to achieve high etching rate, then raised to high temperature (≥0°C) after etching to prevent deposit formation. This dynamic temperature adjustment resolves the contradiction between achieving high productivity during processing and preventing harmful deposit formation afterward.
Solution Approach 2:
The temperature parameter of the electrostatic chuck is changed from a fixed low value to a variable parameter that transitions from low (≤−30°C) to high (≥0°C). This parameter change allows the system to optimize etching rate during the etching process while preventing deposit formation during the post-etching period, thereby resolving the technical contradiction.
2Manufacturing precision
If the temperature of the electrostatic chuck is maintained at low temperature after etching completion, then the etching rate remains high, but the deposit on the target object increases and requires additional cleaning time
Solution Approach 1:
The temperature of the electrostatic chuck is raised to high temperature (≥0°C) immediately after plasma etching completion, before the target object is removed from the chamber. This preliminary temperature increase prevents deposit formation on the target object during the transition period, eliminating the need for additional cleaning time and resolving the contradiction between maintaining etching quality and reducing time loss.
3Productivity
If plasma etching is performed with fluorocarbon gas or hydrofluorocarbon gas at low temperature, then the etching rate is increased, but unnecessary deposits are formed on the target object during the time period from etching completion to target object removal
Solution Approach 1:
The temperature of the electrostatic chuck is dynamically adjusted: maintained at low temperature (≤−30°C) during plasma etching to achieve high etching rate with fluorocarbon or hydrofluorocarbon gas, then raised to high temperature (≥0°C) after etching to prevent condensation and deposit formation. This dynamic adjustment resolves the contradiction between high productivity during etching and preventing target object contamination afterward.
Solution Approach 2:
The temperature change from low (≤−30°C) to high (≥0°C) induces phase transition in the plasma products, preventing them from condensing and forming deposits on the target object. This phase transition mechanism allows the system to maintain high etching rate while avoiding target object contamination.
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 prevents the formation of thick deposits on the target object and reduces processing time by ensuring the target object is free of deposits when removed from the chamber, improving controllability and reducing damage to underlying layers.
Implementation Method 1
The stage has an electrostatic chuck. The electrostatic chuck is configured to hold the target object placed thereon.
Implementation Method 2
raising, immediately after the etching process is performed or immediately after the main etching is performed, the temperature of the electrostatic chuck to be equal to or higher than 0° C. by the temperature control device
Implementation Method 3
the etching of the etching target film including a main etching of etching the etching target film in a state that the temperature of the electrostatic chuck is set to be equal to or lower than −30° C. by the temperature control device
Implementation Method 4
a processing gas is supplied into a chamber, and plasma is generated as the processing gas is excited
Implementation Method 5
This plasma product is condensed or coagulated at a low-temperature place, forming a deposit thereon
Implementation Method 6
This plasma product is condensed or coagulated at a low-temperature place, forming a deposit thereon
Data Source
AI summary
A deposit on a target object can be removed or the amount thereof can be reduced after plasma etching is completed and before the target object is carried out of a chamber. A method of processing the target object is provided. The method includes etching including a main etching of etching an etching target film of the target object placed on a stage at a low temperature by generating plasma of a processing gas containing a fluorocarbon gas and/or a hydrofluorocarbon gas; raising, immediately after the etching is performed or immediately after the main etching is performed, a temperature of an electrostatic chuck; and carrying-out the target object from the chamber in a state that the temperature of the electrostatic chuck is set to a high temperature.