Plasma Processing Apparatus Holding Sheet Thermal Management
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Solution Overview
Problem
In plasma dicing, the holding sheet used for conveying substrates is prone to heat-induced deterioration, leading to stretching, cracking, and wrinkles, which complicates accurate chip recognition and increases the risk of pickup errors, especially when processing thick substrates or those with oxide films, requiring high-power static elimination that further degrades the sheet.
Innovation Solution
A plasma processing apparatus and method that sequentially adsorbs the substrate electrostatically, separates the frame from the stage, generates a repulsive force to detach the holding sheet, and then exposes the substrate to static elimination plasma, minimizing thermal impacts and reducing static buildup, thereby preventing holding sheet deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-power static elimination plasma is used to eliminate residual static charge from thick substrates or substrates with oxide films, then static elimination effectiveness is improved, but the holding sheet is heated and degraded
Solution Approach 1:
The frame is lifted from the stage before static elimination plasma generation. This preliminary action separates the frame (and the holding sheet attached to it) from the stage, allowing the holding sheet to be positioned away from the plasma generation region. Consequently, when high-power plasma is generated for static elimination, the holding sheet is not exposed to excessive heating, thus preventing degradation while maintaining effective static charge elimination from the substrate.
2Duration of action of moving object
If the substrate is kept adsorbed electrostatically throughout prolonged plasma processing, then processing continuity is improved, but residual static charge in the substrate increases
Solution Approach 1:
The plasma processing is divided into two distinct phases: (1) etching plasma generation while the substrate is adsorbed electrostatically to the stage, and (2) static elimination plasma generation after the frame is lifted. This segmentation allows the substrate to remain adsorbed during etching (maintaining processing continuity) but be separated during static elimination (reducing residual static charge), thus resolving the contradiction between processing duration and static charge accumulation.
3Reliability
If the holding sheet is exposed to static elimination plasma while attached to the frame, then static charge elimination is improved, but the holding sheet stretches and snaps causing cracks
Solution Approach 1:
The frame is lifted from the stage before static elimination plasma generation. This preliminary action positions the holding sheet away from the plasma generation region, preventing direct exposure of the holding sheet to high-power plasma. As a result, the holding sheet does not undergo thermal degradation, stretching, or snapping, while the substrate still receives effective static charge elimination through plasma exposure after frame separation.
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 approach effectively suppresses heat-caused deterioration of the holding sheet, allowing for efficient static elimination with reduced power and time, improving chip recognition accuracy and reducing pickup errors.
Implementation Method 1
the substrate is adsorbed together with the holding sheet to the stage of a plasma processing apparatus, by an electrostatic adsorption mechanism called an electrostatic chuck. The electrostatic adsorption mechanism applies a voltage to an electrostatic chuck electrode (hereinafter, ESC electrode) arranged inside the stage, and fixes the substrate to be adsorbed to the stage by a Coulomb force or a Johnson-Rahbek force
Implementation Method 2
fixes the substrate to be adsorbed to the stage by a Coulomb force or a Johnson-Rahbek force that acts between the ESC electrode, and the substrate and the holding sheet
Implementation Method 3
fixes the substrate to be adsorbed to the stage by a Coulomb force or a Johnson-Rahbek force that acts between the ESC electrode, and the substrate and the holding sheet
Implementation Method 4
a plasma generator for generating a plasma within the reaction chamber
Implementation Method 5
a lifting system for lifting and lowering the support
Implementation Method 6
applying to the electrode part a voltage that generates a repulsive force between the substrate and the electrode part, to separate the holding sheet away from the stage
Data Source
AI summary
A plasma processing apparatus for plasma processing a substrate held on a conveying carrier, the carrier including a holding sheet and a frame supporting an outer periphery of the holding sheet. The apparatus includes a controller that controls a plasma generator, an electrostatic adsorption mechanism, and a lifting system, to sequentially execute: an adsorption step allowing the substrate to be adsorbed electrostatically to a stage; an etching step of exposing the substrate adsorbed electrostatically to the stage to an etching plasma; a frame separation step of lifting the support, to separate the frame away from the stage, with at least part of the holding sheet kept in contact with the stage; a holding sheet separation step of separating the holding sheet away from the stage; and a static elimination step of exposing the substrate separated away from the stage to a static elimination plasma.