Substrate Charge Dissipation via Peripheral Underlayer Exposure
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Solution Overview
Problem
In semiconductor manufacturing, electric charging of substrates due to friction during liquid processes can lead to electrostatic breakdown, and existing methods either damage device films or fail to sufficiently remove charges, especially when the substrate is covered with insulating materials.
Innovation Solution
A substrate processing method where a surface insulating layer is partially removed to expose a conductive underlayer, and a conductive substrate holding device is used to dissipate electric charges generated during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive substrate holding device contacts the substrate surface to remove electric charges, then charge removal effect is improved, but the method is ineffective when the entire surface is covered with insulating material
Solution Approach 1:
The substrate surface is segmented into different regions: a central processing region covered with insulating material and a peripheral region where the insulating material is removed or not formed, exposing the conductive underlayer. This allows the holding device to contact the conductive underlayer at the periphery for charge removal while the central region maintains its insulating coverage for device protection.
Solution Approach 2:
The insulating material is selectively removed from the peripheral portion of the substrate, extracting a conductive path area from beneath the insulating layer. This exposed conductive underlayer serves as a charge dissipation path, allowing the holding device to remove electric charges without compromising the insulating protection over the device region.
2Reliability
If an acidic or alkaline rinse liquid is used to suppress electrostatic breakdown, then charge suppression is improved, but damage to device films occurs
Solution Approach 1:
A conductive underlayer is introduced as an intermediary between the insulating surface layer and the substrate base. This conductive layer acts as a charge dissipation path, allowing electric charges to be safely removed through the holding device without requiring acidic or alkaline rinse liquids that could damage device films.
3Reliability
If the surface insulating layer is removed to expose conductive underlayer, then charge dissipation path is improved, but device protection is reduced
Solution Approach 1:
The substrate is given non-uniform properties: the central region maintains insulating material coverage to protect devices, while the peripheral region has removed insulating material to expose the conductive underlayer. This local differentiation allows simultaneous achievement of charge dissipation (at periphery) and device protection (at center).
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 method effectively removes electric charges from the substrate, preventing electrostatic breakdown by utilizing the conductive underlayer and holding device to dissipate charges before they accumulate.
Implementation Method 1
at least a portion of the substrate holding device which comes into contact with the underlayer is made of a conductive material. Further, in the performing of the process on the substrate, an electric charge generated in the surface insulating layer of the substrate is removed via the underlayer and the substrate holding device
Data Source
AI summary
Electric charging of a substrate caused by a friction between a fluid and a surface of the substrate being rotated can be suppressed. At least a part of a surface insulating layer (thermal oxide film) on a peripheral portion of a substrate W is removed, and an underlayer (silicon wafer) having higher conductivity than a material of the surface insulating layer is exposed. Then, a process is performed on the substrate while holding and rotating the substrate by a substrate holding device. Here, at least a portion of the substrate holding device which comes into contact with the underlayer is made of a conductive material. In performing the process on the substrate, an electric charge generated in the surface insulating layer of the substrate is removed via the underlayer and the substrate holding device.