PECVD Backside Deposition Chamber for Wafer Bow Control
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Solution Overview
Problem
Semiconductor wafers experience warping and stress due to the buildup of layers on the top-side during deposition, which can affect subsequent processing steps and lead to increased handling issues and reduced processing yield when attempting to counteract this by flipping the wafer for back-side deposition.
Innovation Solution
A plasma processing system with a shower-pedestal configured opposite a showerhead in a plasma processing chamber, allowing for back-side deposition by supplying process gases through a carrier ring that spaces the substrate apart from the shower-pedestal, while the showerhead provides purge gases to prevent deposition on the top-side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If wafer flipping is performed to deposit materials on the back-side, then wafer bowing is counteracted and stress is reduced, but processing yield is reduced and handling complexity increases
Solution Approach 1:
Instead of flipping the wafer to access the back-side for deposition, the invention inverts the approach by keeping the wafer in its original orientation and delivering deposition gases to the back-side through the shower-pedestal from below, thereby eliminating the need for wafer flipping while achieving stress balance
Solution Approach 2:
The shower-pedestal acts as an intermediary component that enables back-side deposition without requiring wafer flipping. It delivers process gases through holes in its structure to the back-side of the wafer, serving as a mediator between the gas source and the wafer back-side surface
2Shape
If wafer flipping is performed to deposit materials on the back-side, then wafer bowing is counteracted, but handling complexity and particle exposure increase
Solution Approach 1:
The invention inverts the conventional approach by delivering gases to the back-side through the shower-pedestal from below while the wafer remains front-side up, eliminating the need for flipping operations and associated handling complexity
Solution Approach 2:
The shower-pedestal structure itself provides the mechanism for back-side gas delivery through its inherent hole pattern, eliminating the need for external flipping mechanisms and simplifying the overall system architecture
3Adaptability or versatility
If shower-pedestal is used for back-side deposition, then selective deposition is achieved and wafer bowing is counteracted, but device complexity increases
Solution Approach 1:
The shower-pedestal is designed to serve multiple functions: it acts as a support structure for the wafer, a gas delivery system for back-side deposition, and a structural component of the chamber. This multi-functionality reduces the need for separate dedicated components
Solution Approach 2:
The shower-pedestal incorporates a pattern of holes that allow process gases to pass through and reach the back-side of the wafer. This porous structure enables selective gas delivery to specific regions or the entire back-side surface
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 solution effectively counteracts wafer warping by depositing films on the back-side, achieving neutral stress and minimizing bowing, thereby improving processing control and yield without the need for wafer flipping, thus reducing handling issues and maintaining high processing efficiency.
Implementation Method 1
PECVD systems convert a liquid precursor into a vapor precursor, which is delivered to a chamber. PECVD systems may include a vaporizer that vaporizes the liquid precursor in a controlled manner to generate the vapor precursor.
Implementation Method 2
The showerhead, in one embodiment, is configured to supply purge gases, e.g., inert gases, to prevent the backside deposition gases from forming materials layers on the topside of the substrate.
Implementation Method 3
A radio frequency (RF) power supply for providing power to the showerhead to generate a plasma is provided. The plasma is used for depositing a film on a back-side of the substrate
Data Source
AI summary
A plasma processing system is provided. The system includes a chamber, a controller and a showerhead disposed in the chamber. A first gas manifold is connected to the showerhead for providing a first gas from a first gas source responsive to control from the controller. A shower-pedestal is disposed in the chamber and oriented opposite the showerhead. A second gas manifold is connected to the shower-pedestal for providing a second gas from a second gas source responsive to control from the controller. A substrate support for holding a substrate at a spaced apart relationship from the shower-pedestal is provided. A radio frequency (RF) power supply for providing power to the showerhead to generate a plasma is provided. The plasma is used for depositing a film on a back-side of the substrate, when present in the chamber. The substrate is held by the substrate support in the spaced apart relationship from the shower-pedestal, during backside deposition. The showerhead provides a purge gas during the backside deposition.