Embedded Conductive Ring for Electrostatic Clamp Charge Drainage
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Solution Overview
Problem
Conventional ion implanters face substrate damage due to electrostatic charge buildup and inadequate charge drainage during the substrate release process, leading to potential contamination and mechanical damage.
Innovation Solution
An electrostatic clamp with an embedded conductive region in the top dielectric layer and conductive vias connected to ground, ensuring effective charge drainage from the substrate's backside surface, regardless of its orientation, using fluid conduits that pass through the clamp layers to provide a reliable grounding path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrostatic clamp without embedded conductive region is used, then substrate can be held in place during ion implantation, but electrostatic charge buildup occurs on substrate backside leading to substrate sticking and potential damage during release
Solution Approach 1:
The clamp structure is segmented into multiple functional layers: a top dielectric layer for electrostatic clamping, an embedded conductive region within the dielectric layer for charge drainage, and conductive vias connecting to ground. This segmentation allows the top layer to maintain substrate holding stability while the embedded conductive region and vias independently handle charge drainage, resolving the contradiction between holding stability and charge buildup prevention.
Solution Approach 2:
The embedded conductive region acts as an intermediary element within the dielectric layer, providing a localized charge drainage path without compromising the overall dielectric integrity needed for electrostatic clamping. The conductive vias serve as intermediaries to connect the embedded conductive region to the ground, enabling charge dissipation while maintaining the clamp's holding capability.
2Productivity
If substrate is released from electrostatic clamp without adequate charge drainage, then substrate can be removed, but substrate breakage and contamination occur due to electrostatic discharge
Solution Approach 1:
The embedded conductive region and conductive vias provide continuous charge drainage during the substrate release process, performing the charge dissipation action in advance before substrate removal. This preliminary charge drainage prevents electrostatic discharge and substrate damage during release, enabling fast substrate removal while maintaining substrate integrity.
3Object-affected harmful factors
If ground pins are used to drain charge from substrate, then charge drainage is provided, but substrate backside contamination and damage occur from pin contact
Solution Approach 1:
The charge drainage function is extracted from the substrate-backside contact mechanism (ground pins) and relocated to an embedded conductive region within the dielectric layer. This extraction eliminates the need for direct pin contact with the substrate backside, providing effective charge drainage while preventing contamination and damage from mechanical contact.
4Force
If top dielectric layer is made highly insulating to maintain electrostatic field, then substrate holding force is improved, but charge drainage capability is reduced
Solution Approach 1:
The dielectric layer exhibits local quality variation: the top portion maintains high insulating properties for strong electrostatic holding, while the embedded conductive region within the dielectric layer provides localized charge drainage pathways. This local quality differentiation allows the structure to simultaneously achieve high holding force through the insulating top layer and effective charge drainage through the embedded conductive region.
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 reduces substrate sticking and breakage by ensuring sufficient charge drainage, minimizing contamination and mechanical damage during the substrate release process.
Implementation Method 1
To effectively hold the substrate 114 in place, most workpiece supports typically use electrostatic force. By creating a strong electrostatic force on the upper side of the workpiece support 116, the support can serve as the electrostatic clamp or chuck
Implementation Method 2
An electrostatic clamp with an embedded conductive region in the top dielectric layer and conductive vias connected to ground, ensuring effective charge drainage from the substrate's backside surface
Implementation Method 3
ions are generated in the ion source 102 and extracted by the extraction electrodes 104. The extracted ions 10 travel in a beam-like state along the beam-line components and implanted on the substrate 114
Data Source
AI summary
An electrostatic clamp which more effectively removes built up charge from a substrate prior to removal is disclosed. Currently, the lift pins and the ground pins are the only mechanism used to remove charge from the substrate after implantation. The present discloses describes an electrostatic chuck in which the top dielectric surface has an embedded conductive region, such as a ring shaped conductive region in the sealing ring. Thus, regardless of the orientation of the substrate during release, at least a portion of the substrate will contain the conductive region on the dielectric layer of the workpiece support. This conductive region may be connected to ground through the use of conductive vias in the dielectric layer. In some embodiments, these conductive vias are the fluid conduits used to supply gas to the back side of the substrate.