Electrostatic Substrate Support for Plasma Processing
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Solution Overview
Problem
The challenge in electronic device fabrication is securing insulator substrates during plasma processing without mechanical clamping, which can damage the substrates and reduce yield, as existing methods like electrical discharge or high-temperature techniques are inefficient and costly.
Innovation Solution
An electrostatic-type substrate support structure with a ceramic conductive layer is used, where the clamping voltage is controlled in a step-wise or pulsed manner to minimize charge accumulation and facilitate rapid release of the substrate, avoiding the need for mechanical clamping and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical clamping devices are used to hold the insulator substrate, then the substrate is securely held during plasma processing, but the substrate yield is reduced and potential damage occurs
Solution Approach 1:
The patent replaces mechanical clamping devices with an electrostatic field-based holding system. A support structure with conductive elements generates an electrostatic field that attracts and holds the insulator substrate without physical contact, eliminating mechanical stress and damage while maintaining secure positioning during plasma processing
Solution Approach 2:
The patent introduces an electrostatic field as an intermediary between the support structure and the insulator substrate. This field-based intermediary enables force transmission for substrate holding without direct mechanical contact, thereby preventing substrate damage and preserving yield
2Ease of operation
If high-temperature techniques are used to release the substrate, then the substrate can be released from the support structure, but the processing time and energy consumption increase
Solution Approach 1:
The patent employs periodic or pulsed electrostatic field application to the support structure. By periodically reversing or modulating the electrostatic field, the substrate can be rapidly released without requiring sustained high temperatures, thereby reducing both time and energy consumption while maintaining effective release capability
Solution Approach 2:
The patent changes the electrical parameters (voltage, polarity, pulse duration) of the electrostatic field to control substrate release. By adjusting these parameters, the substrate can be quickly released from the support structure without invoking thermal processes, thus minimizing time loss and energy expenditure
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 reduces the time required for substrate release, minimizes charge dissipation, and maintains adequate holding force, thereby enhancing fabrication throughput and reducing potential damage to devices and equipment.
Implementation Method 1
An electrostatic-type substrate support structure with a ceramic conductive layer is used
Implementation Method 2
the clamping voltage is controlled in a step-wise or pulsed manner to minimize charge accumulation and facilitate rapid release of the substrate
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
An insulator-type substrate (105) is positioned on a support surface of a substrate support structure (103) in exposure to a plasma (123). An initial clamping voltage is applied to an electrode (107) within the substrate support structure to rapidly accumulate electrical charge on the support surface to hold the substrate. A backside cooling gas is flowed to a region between the substrate and the support surface, and a leak rate of the backside cooling gas is monitored. A steady clamping voltage is applied to the electrode, and the steady clamping voltage is adjusted in a step-wise manner to maintain the monitored leak rate of the backside cooling gas at just less than a maximum allowable leak rate. Or, a pulsed clamping voltage is applied to the electrode, and the pulsed clamping voltage is adjusted to maintain the monitored leak rate of the backside cooling gas at just less than the maximum allowable leak rate.