Wafer Edge Removal Using Modification Layers to Prevent Chipping
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Solution Overview
Problem
Conventional edge trim methods for semiconductor wafers using grinding tools result in chipping and require significant grinding water, leading to high running costs and the need for frequent whetstone replacement, while also posing challenges in accurately removing peripheral portions without damaging the wafer.
Innovation Solution
A substrate processing apparatus and method that employs a periphery removing unit with a wedge roller to separate and remove the peripheral portion of a combined wafer by forming a periphery modification layer and divided modification layers, allowing for precise removal without grinding, thus reducing waste and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a grinding tool is used to remove the peripheral portion of a semiconductor wafer, then the peripheral portion can be removed, but chipping occurs on the wafer surface
Solution Approach 1:
The patent replaces the mechanical grinding system with a chemical etching system. Instead of using abrasive grains on a rotating whetstone to mechanically remove material, the invention uses a periphery modification layer that is chemically etched away by a buffered hydrofluoric acid solution. This substitution eliminates the mechanical contact that causes chipping while achieving precise peripheral portion removal through controlled chemical reactions.
2Loss of substance
If a grinding tool is used to remove the peripheral portion, then material removal is achieved, but significant grinding water is required leading to high running costs
Solution Approach 1:
The invention replaces the water-intensive mechanical grinding process with a controlled chemical etching process. The periphery modification layer is selectively etched using buffered hydrofluoric acid, which removes the peripheral portion without requiring large amounts of grinding water for cooling and lubrication. This significantly reduces water consumption and associated running costs.
3Productivity
If a grinding tool is used, then peripheral portion removal is achieved, but frequent whetstone replacement is required
Solution Approach 1:
The patent replaces the consumable whetstone with a reusable periphery modification layer formed through laser irradiation. Instead of mechanically grinding with a whetstone that wears out and requires frequent replacement, the invention creates a modified layer on the wafer periphery that is selectively etched away. This eliminates whetstone replacement needs while maintaining high productivity through controlled chemical etching.
4Manufacturing precision
If conventional grinding is used, then peripheral portion can be removed, but accurate processing without damage is difficult to achieve
Solution Approach 1:
The invention applies preliminary action by first forming a periphery modification layer through laser irradiation before the etching process. This pre-modification creates a distinct layer with different chemical properties that can be selectively removed by buffered hydrofluoric acid. The preliminary laser treatment enables precise boundary definition and controlled material removal without the risk of mechanical damage that occurs during conventional grinding operations.
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
The method effectively removes the peripheral portion of semiconductor wafers with reduced risk of chipping and lower operational costs by eliminating the need for grinding tools and associated water usage, while ensuring accurate processing.
Implementation Method 1
a periphery removing unit configured to remove, starting from a periphery modification layer formed on the first substrate along a boundary between a peripheral portion to be removed and a central portion of the first substrate, the peripheral portion from the combined substrate held by the substrate holder
Data Source
AI summary
A substrate processing apparatus configured to process a substrate includes a substrate holder configured to hold, in a combined substrate in which a first substrate and a second substrate are bonded to each other, the second substrate; a periphery removing unit configured to remove, starting from a periphery modification layer formed on the first substrate along a boundary between a peripheral portion to be removed and a central portion of the first substrate, the peripheral portion from the combined substrate held by the substrate holder; and a collection unit equipped with a collection mechanism configured to collect the peripheral portion removed by the periphery removing unit.