Eccentricity Detection and Laser Modification for Wafer Edge Trimming

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Solution Overview

Problem

Conventional substrate processing methods, such as those using disk-shaped grinding tools, face challenges in accurately controlling the movement of the grinding wheel, leading to potential damage to semiconductor wafers due to uneven grinding, which can result in bending, cracking, or chipping, especially when trimming the peripheral edges.

Innovation Solution

A substrate processing system equipped with an eccentricity detection device, a modification layer forming device, and a periphery removing device, which forms an annular modification layer within the substrate using a laser beam to facilitate precise removal of the peripheral portion, thereby avoiding damage and improving accuracy and throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a disk-shaped grinding tool is rotated and brought into linear contact with a semiconductor wafer to grind the circumferential end, then the peripheral portion can be removed, but the movement control of the grinding wheel becomes difficult leading to uneven grinding and potential damage to the substrate

Engineering Contradiction:

Improveperipheral removal efficiencyVSAvoidgrinding uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention forms a modification layer within the substrate along the boundary between the peripheral portion to be removed and the central portion before removal. This preliminary action creates a predetermined removal reference line that guides the grinding process, ensuring uniform grinding while maintaining efficient peripheral removal. The modification layer serves as a pre-established reference that prevents uneven grinding during the subsequent removal process.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the grinding wheel moves during the grinding process, then peripheral removal can be performed, but uneven grinding occurs causing bending, cracking, or chipping of the semiconductor wafer

Engineering Contradiction:

Improveperipheral trimming capabilityVSAvoidsubstrate integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The modification layer is formed in advance along the boundary before the grinding process. This preliminary formation of the modification layer creates a controlled reference line that prevents uneven grinding during peripheral removal, thereby maintaining substrate integrity and preventing damage such as bending, cracking, or chipping while still enabling effective peripheral trimming.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The modification layer acts as an intermediary element between the grinding wheel and the substrate. It provides a predetermined removal reference line that mediates the interaction between the grinding tool and the substrate, ensuring uniform material removal while protecting the substrate from damage. The modification layer absorbs the mechanical stress and guides the grinding process to maintain substrate integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of substance

If conventional grinding methods are used to remove the peripheral portion, then material removal is achieved, but accuracy is compromised and damage such as chipping and cracking may occur

Engineering Contradiction:

Improveperipheral material removalVSAvoidremoval accuracy

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The modification layer is formed in advance along the boundary between the peripheral portion to be removed and the central portion. This predetermined reference line enables precise control of the removal process, ensuring that material is removed accurately along the intended path while preventing damage such as chipping and cracking. The modification layer serves as a guide that maintains high removal accuracy throughout the grinding process.

Inventive Principle:

Principle #10Preliminary action

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 system ensures high accuracy in removing the peripheral portion with minimal damage to the substrate, reducing the risk of chipping and cracking, and enhancing processing efficiency by allowing for precise control over the grinding process, thus improving the overall quality and speed of wafer processing.

Implementation Method 1

a modification layer forming device configured to form a modification layer within the first substrate along a boundary between a peripheral portion to be removed and a central portion of the first substrate

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

an eccentricity detection device configured to detect, in a combined substrate in which a first substrate and a second substrate are bonded to each other, an eccentricity of the first substrate

Methodology Applied

Scientific EffectOptical detection:

Data Source

PatentUS11450523B2Substrate processing system with eccentricity detection device and substrate processing method

Publication Date: 2022.09.20 TOKYO ELECTRON LTD

AI summary

A substrate processing system configured to process a substrate includes an eccentricity detection device configured to detect, in a combined substrate in which a first substrate and a second substrate are bonded to each other, an eccentricity of the first substrate; a modification layer forming device configured to form a modification layer within the first substrate along a boundary between a peripheral portion to be removed and a central portion of the first substrate; and a periphery removing device configured to remove the peripheral portion starting from the modification layer.