Shower Plate Ring for Plasma Density Uniformity
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Solution Overview
Problem
Existing plasma CVD apparatuses face challenges in achieving uniform plasma processing across the entire substrate surface, leading to insufficient film formation and degraded film quality at the outer edges of substrates due to non-uniform plasma density.
Innovation Solution
A substrate processing apparatus with a shower plate featuring a conductor plate part and a ring-shaped conductor part connected to its outer edge, along with a lead wire embedded in the ring-shaped part to supply DC current, generating a magnetic field above the substrate's outer edge, which enhances plasma density uniformity by trapping electrons in a doughnut-shaped region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional shower plate is used in plasma CVD apparatus, then the apparatus structure is simple, but the plasma density becomes non-uniform across the substrate surface resulting in degraded film quality at outer edges
Solution Approach 1:
The shower plate is divided into two distinct conductor parts with different functions: a plate part for gas distribution and a ring-shaped part for magnetic field generation. This local differentiation allows each part to optimize its specific function, with the ring-shaped part creating enhanced plasma density at the substrate outer edges where it is most needed.
Solution Approach 2:
The shower plate functions as a composite structure combining two conductor parts made of conductive material. The plate part and ring-shaped part work together synergistically, where the ring-shaped part generates magnetic fields that confine plasma electrons, creating a composite effect that achieves uniform plasma density across the entire substrate surface.
2Manufacturing precision
If DC current is supplied to the ring-shaped part to generate magnetic field, then plasma density uniformity is improved, but the device complexity and power supply requirements increase
Solution Approach 1:
The ring-shaped conductor part serves multiple functions: it acts as both a structural component of the shower plate and an electromagnetic coil for magnetic field generation. By integrating these functions into a single element, the design avoids adding separate complex magnetic field generation systems while achieving improved plasma uniformity.
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 ensures consistent plasma density across the substrate, enabling uniform plasma processing and improving film thickness and quality by preventing electron attraction to the center, thus addressing the non-uniformity issues in existing technologies.
Implementation Method 1
a lead wire embedded in the ring-shaped part and surrounding the plate part and the susceptor in plan view, the shower plate being provided so as to face the susceptor in the chamber, and a DC power supply that supplies a direct current to the lead wire
Implementation Method 2
generating a magnetic field above the substrate's outer edge, which enhances plasma density uniformity by trapping electrons in a doughnut-shaped region
Implementation Method 3
supplying a gas onto the substrate via the plurality of through holes and thereby generating plasma on the substrate
Data Source
AI summary
A substrate processing apparatus includes a chamber, a susceptor provided in the chamber, a shower plate having a plate part provided with a plurality of through holes and formed of a conductor, a ring-shaped part connected to an outer edge of the plate part, surrounding the plate part and formed of a conductor and a lead wire embedded in the ring-shaped part and surrounding the plate part and the susceptor in plan view, the shower plate being provided so as to face the susceptor in the chamber, and a DC power supply that supplies a direct current to the lead wire.