Digital Plasma Element Control for Wafer Uniformity
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Solution Overview
Problem
Plasma processing in the semiconductor industry faces challenges in achieving uniformity across wafers due to numerous interfering factors, leading to large and expensive chamber designs, and analog control systems lack the flexibility required for modern process control, making it difficult to meet stricter uniformity criteria and adapt to quick changes in chemistry.
Innovation Solution
Implementing a digital process control system that uses a plasma controller to activate plasma elements based on specific exposure values and durations, allowing for independent and time-dependent exposure of plasma fluxes to substrates, enabling precise control and flexibility in plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If analog control systems are used for plasma processing, then the system can operate with simpler hardware, but the system lacks flexibility and cannot meet stricter uniformity criteria
Solution Approach 1:
The plasma processing system is divided into multiple independently controllable plasma elements (e.g., multiple RF coils or plasma sources) that can be individually addressed and controlled. This segmentation allows digital control of each element's plasma flux to the substrate, enabling precise spatial and temporal control without requiring complex analog control circuitry for the entire system.
Solution Approach 2:
The patent replaces analog control mechanisms with digital control systems. Instead of using continuous analog signals to control plasma parameters, the system uses digital addressing and switching to control individual plasma elements, thereby achieving flexibility while avoiding the complexity of analog control systems.
2Manufacturing precision
If chamber dimensions and power generators are increased to achieve higher process uniformity, then uniformity improves, but the equipment size and cost increase
Solution Approach 1:
Instead of relying on large chamber dimensions to achieve uniformity, the patent applies local quality control by enabling independent control of plasma flux to different regions of the substrate. Each plasma element can be individually adjusted to compensate for local non-uniformities, achieving high manufacturing precision without increasing overall chamber size.
Solution Approach 2:
The system introduces dynamic control capabilities where plasma element activation and exposure durations can be adjusted in real-time based on process requirements. This dynamic control allows the system to adapt to different uniformity requirements without requiring larger physical dimensions.
3Manufacturing precision
If complex temperature control and coil splitting measures are implemented, then basic process uniformity is achieved, but the system becomes expensive and inadequate for stricter criteria
Solution Approach 1:
The patent segments the plasma generation system into multiple independently controllable elements, replacing complex temperature control and coil splitting measures with simpler digital control of individual plasma sources. This segmentation allows each element to be independently optimized without requiring complex inter-element coordination.
4Manufacturing precision
If large plasma volume is used to achieve process uniformity, then uniformity improves, but the system cannot quickly change chemistry
Solution Approach 1:
By dividing the plasma system into multiple discrete elements, the patent enables selective activation and deactivation of individual plasma sources. This allows rapid chemistry changes by simply switching which plasma elements are active, without requiring large plasma volumes that would slow down chemistry transitions.
Data Source
AI summary
A system including a control plate disposed within a processing chamber. The control plate includes a set of plasma elements designed to independently expose a substrate disposed within the processing chamber to plasma related fluxes. The control plate is designed to independently activate the set of plasma elements. When activated the associated plasma elements expose the substrate to the plasma related fluxes and when not activated the associated plasma elements prevent exposure of the substrate to the plasma related fluxes. The control plate is designed to perform individual time-dependent activation of the set of plasma elements to selectively expose the substrate to the plasma related fluxes.