Polishing Tape Edge Alignment for Right-Angled Substrate Profiles

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Solution Overview

Problem

Conventional polishing apparatuses for semiconductor substrates often result in oblique edge surfaces during the polishing of peripheral portions, leading to acute edges that can break and cause defects, lowering the yield in fabrication processes.

Innovation Solution

A polishing apparatus and method that includes a substrate holder for rotating the substrate and a polishing unit with a pressing member to press a polishing tape against the substrate from above, ensuring the polishing tape is parallel to the substrate surface, and using a tape-edge detection sensor to align the tape edge with the pressing member, allowing for a right-angled cross-sectional shape to be formed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an inclined polishing tape is used to polish the top edge portion of the substrate, then the polishing process can be performed, but an oblique edge surface is formed on the device layer, leading to acute edges that are easily broken

Engineering Contradiction:

Improvepolishing processabilityVSAvoidedge surface flatness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Instead of inclining the polishing tape to access the top edge portion, the invention inverts the approach by using a vertically oriented polishing tape that contacts the top edge portion from above. The polishing tape is pressed downward by a pressing member, reversing the conventional inclination method and achieving a right-angled edge surface instead of an oblique one.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the dimensional approach by moving the polishing action from a lateral inclination to a vertical dimension. The polishing tape extends in the radial direction of the substrate and contacts the top edge portion vertically, adding a vertical component to the polishing process that eliminates the oblique surface formation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If a right-angled member is used to press the polishing tape against the substrate, then the polishing can be performed, but the polishing tape is rounded at the corner due to its thickness and hardness, still forming an oblique edge surface

Engineering Contradiction:

Improveedge surface flatnessVSAvoidpolishing apparatus structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the pressing function from a complex right-angled mechanical member and implements it through a simpler pressing member that applies vertical force. The pressing member is configured to press the polishing tape downward without requiring complex right-angled structures, simplifying the apparatus while achieving the desired right-angled edge surface.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the orientation parameter of the polishing tape from inclined to vertical. By adjusting the tape extension direction to be parallel to the radial direction of the substrate and pressing it vertically downward, the corner rounding issue is eliminated while maintaining manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the polishing tape is pressed against the peripheral portion of the substrate, then the unwanted films can be removed, but the tape must be precisely positioned to avoid forming oblique surfaces

Engineering Contradiction:

ImproveyieldVSAvoidtape positioning accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The polishing apparatus is designed to polish multiple regions of the substrate periphery using the same vertical polishing mechanism. The pressing member can be positioned to polish the top edge portion, bottom edge portion, and bevel portion, providing universal functionality that reduces positioning complexity while maintaining high yield through consistent right-angled surface formation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution effectively polishes the substrate's peripheral portion to achieve a right-angled cross-sectional shape, reducing the risk of edge breakage and defects, thereby improving yield in semiconductor device fabrication.

Implementation Method 1

polishing the peripheral portion of the substrate W by bringing a polishing surface of a polishing tape 38 into contact with the peripheral portion of the substrate W

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS9457447B2Polishing apparatus and polishing method

Publication Date: 2016.10.04 EBARA CORP

AI summary

The polishing apparatus has a polishing unit capable of forming a right-angled cross section by polishing a peripheral portion of the substrate. The polishing unit includes a polishing head having a pressing member configured to press a polishing tape against the peripheral portion of the substrate from above, a tape supply and recovery mechanism configured to supply the polishing tape to the polishing head and to recover the polishing tape from the polishing head, a first moving mechanism configured to move the polishing head in a radial direction of the substrate, and a second moving mechanism configured to move the tape supply and recovery mechanism in the radial direction of the substrate. The guide rollers are arranged such that the polishing tape extends parallel to a tangential direction of the substrate and a polishing surface of the polishing tape is parallel to a surface of the substrate.