Electrostatic Chuck Dechucking for Uniform Remote Plasma Deposition
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Solution Overview
Problem
Semiconductor processing apparatuses face challenges in achieving uniform deposition and efficient dechucking of substrates due to substrate bowing and unwanted backside deposition, particularly in remote plasma processing where ceramic pedestals can cause thermal and deposition non-uniformities and wafer handling issues.
Innovation Solution
A remote plasma apparatus with an electrostatic chuck that includes a ceramic platen with embedded electrodes for clamping and heating, allowing for precise temperature control and secure substrate retention, along with a method of dechucking by reversing polarity and reducing voltage sequences to minimize residual sticking forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic pedestal is used in remote plasma processing, then substrate heating is achieved, but thermal non-uniformities and substrate bowing occur
Solution Approach 1:
The substrate support structure is segmented into a separate electrostatic chuck assembly that can be independently controlled, rather than relying on the entire ceramic pedestal for heating and support. This allows the electrostatic chuck to provide localized, uniform heating and clamping forces.
Solution Approach 2:
The mechanical/clamp-based substrate holding system is replaced with an electrostatic field-based system. The electrostatic chuck uses electrical fields to clamp the substrate uniformly across its surface, eliminating the mechanical contact points that cause bowing and non-uniform heating.
2Ease of operation
If a ceramic pedestal is used in remote plasma processing, then substrate support is provided, but unwanted backside deposition occurs
Solution Approach 1:
The electrostatic chuck assembly is extracted as a separate functional unit from the ceramic pedestal, allowing it to be positioned and controlled independently. This separation enables precise control over where deposition occurs, preventing material from depositing on the substrate backside by maintaining proper electrical isolation and positioning.
3Force
If electrostatic chuck voltage is applied for substrate clamping, then secure substrate retention is achieved, but residual sticking forces remain after dechucking
Solution Approach 1:
The dechucking process uses periodic voltage sequences with multiple polarity reversals and gradual voltage reductions. This periodic action systematically eliminates residual sticking forces by applying controlled electrostatic fields in alternating directions, ensuring complete substrate release without damage.
Solution Approach 2:
Before complete substrate release, preliminary voltage reduction steps are applied to gradually minimize the clamping force. This preliminary action prevents sudden substrate release that could cause mishandling, allowing the substrate to be carefully extracted from the electrostatic field.
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 solution enables uniform silicon-containing film deposition with high step coverage and reduced wafer mishandling, maintaining substrate flatness and preventing backside deposition, thus improving processing efficiency and film quality.
Implementation Method 1
an electrostatic chuck for clamping the wafer to the electrostatic chuck by an electrostatic attractive force
Implementation Method 2
one or more heating elements configured to heat the semiconductor substrate to a temperature between about 300° C. and about 750° C.
Implementation Method 3
an RF power supply configured to power plasma in the remote plasma source
Implementation Method 4
a showerhead fluidly coupled to the reaction chamber for delivery of plasma-activated species from the remote plasma source to the reaction chamber
Data Source
AI summary
A remote plasma processing apparatus with an electrostatic chuck can deposit film on a semiconductor substrate by atomic layer deposition or chemical vapor deposition. The remote plasma processing apparatus can include a remote plasma source and a reaction chamber downstream from the remote plasma source. An RF power source can be configured to apply high RF power to the remote plasma source and heating elements can be configured to apply high temperatures to the electrostatic chuck. The semiconductor substrate can be dechucked from the electrostatic chuck using a declamping routine that alternates reversing polarities and reducing clamping voltages. In some embodiments, silicon nitride film can be conformally deposited by atomic layer deposition using a mixture of nitrogen, ammonia, and hydrogen gases as a source gas for remote plasma generation.