Plasma Electrode Geometry for Vertical Wafer Uniformity
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Solution Overview
Problem
In vertical batch type plasma processing apparatuses, there is a subtle difference in deposition rate and film quality between semiconductor wafers stacked in upper and lower stages of the process chamber, which may hinder further development in high integration and miniaturization of semiconductor integrated circuit devices.
Innovation Solution
The apparatus includes a plasma generation chamber with plasma active species generated and supplied to a process chamber where wafers are stacked, featuring a plasma source gas supply pipe with gas discharge holes and a pair of plasma electrodes that apply an electric field, with the discharge area size and RF power distribution varied in the vertical direction to ensure uniform plasma active species concentration across the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical batch type plasma processing apparatus is used to improve throughput, then productivity increases, but a subtle difference occurs in deposition rate and film quality between wafers on upper and lower stages
Solution Approach 1:
The patent applies local quality by varying the discharge area size of plasma electrodes along the vertical direction. The discharge area is made larger at lower positions and smaller at upper positions within the process chamber. This non-uniform electrode configuration compensates for the natural decrease in plasma active species concentration at higher positions, thereby achieving uniform deposition rates and film quality across all wafer stages while maintaining high throughput vertical batch processing.
2Productivity
If wafers are vertically stacked to increase throughput, then productivity improves, but deposition rate and film quality uniformity deteriorates between upper and lower stages
Solution Approach 1:
The patent implements local quality by configuring plasma electrodes with position-dependent discharge area sizes. The discharge area is deliberately designed to be larger at lower vertical positions and smaller at upper positions. This local variation in electrode geometry compensates for the vertical gradient in plasma active species concentration, ensuring that each wafer stage receives appropriate plasma flux for uniform film quality and deposition rate across all vertically stacked wafers.
3Device complexity
If a conventional plasma processing apparatus is used, then device complexity remains low, but deposition rate and film quality uniformity across vertical stages is poor
Solution Approach 1:
The patent resolves the contradiction by implementing a relatively simple structural modification: plasma electrodes with discharge areas that vary along the vertical direction. This design achieves uniform deposition and film quality across vertically stacked wafers without introducing complex additional components or systems. The electrode geometry itself serves as the compensation mechanism, maintaining low device complexity while significantly improving manufacturing precision.
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 configuration reduces the subtle differences in deposition rate and film quality between wafers on upper and lower stages, achieving more uniform plasma active species distribution and improved film quality.
Implementation Method 1
a pair of plasma electrodes, arranged to face each other, configured to apply an electric field to the plasma source gas discharged into the plasma generation chamber
Implementation Method 2
a plasma generation chamber in which plasma active species are generated, a process chamber configured to accommodate therein processing target objects which are stacked in a vertical direction, the plasma active species generated in the plasma generation chamber being supplied into the process chamber
Data Source
AI summary
A plasma processing apparatus includes a plasma generation chamber in which plasma active species are generated, a process chamber configured to accommodate processing target objects stacked in a vertical direction, the plasma active species generated in the plasma generation chamber being supplied into the process chamber, a plasma source gas supply pipe disposed inside the plasma generation chamber and extending in the vertical direction, a plasma source gas being introduced from one end of the plasma source gas supply pipe and discharged through gas discharge holes formed in the plasma source gas supply pipe in the vertical direction, and a pair of plasma electrodes, arranged to face each other, configured to apply an electric field to the plasma source gas discharged into the plasma generation chamber. A size of a discharge area interposed between the pair of plasma electrodes is varied in the vertical direction.