Wafer Edge Trimming Stepped Oblique Region

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Solution Overview

Problem

In semiconductor wafer manufacturing, the grinding process often results in significant off-cuts from the outer peripheral portion, especially when chamfered parts are present, which are difficult to collect and can lead to worker manual handling, increasing the risk of breakage and inefficiency.

Innovation Solution

An edge trimming method that forms a stepped oblique region on the outer peripheral portion of the wafer by repeatedly moving and rotating a cutting blade relative to the chuck table, reducing the volume and arcuate length of off-cuts generated during grinding, allowing for more effective collection by automated systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If edge trimming is performed to remove chamfered part before grinding, then breakage of workpiece is avoided, but large arcuate off-cuts are generated that cannot be collected by automated systems

Engineering Contradiction:

Improveworkpiece breakage preventionVSAvoidoff-cut volume

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The edge trimming process is divided into multiple cutting steps that create a stepped oblique region with multiple tiers instead of a single deep cut. This segmentation reduces the volume of each off-cut segment and allows them to be collected by automated debris collection systems during grinding, while still preventing workpiece breakage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stepped oblique region is formed as a preliminary structure before the grinding process. By pre-forming this stepped structure with controlled depth and angle, the workpiece is prepared to withstand grinding forces without breakage, while the reduced off-cut volume can be properly collected.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If single-step edge trimming is performed, then process is simple, but large off-cuts are generated requiring manual collection

Engineering Contradiction:

Improveedge trimming simplicityVSAvoidoff-cut collection efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The cutting process is segmented into multiple shallow cuts that form stepped regions, replacing a single deep cut. This maintains manufacturing simplicity while dramatically improving off-cut collection efficiency by reducing off-cut volume to collectible sizes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cutting approach transitions from a single-depth vertical cut to a multi-level stepped structure. By adding the dimensional aspect of multiple tiers at different depths, the process maintains simplicity while enabling automated collection of smaller off-cut segments.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Loss of substance

If multiple annular steps are formed by repeated cutting, then off-cut volume is reduced, but processing time increases

Engineering Contradiction:

Improveoff-cut volume reductionVSAvoidedge trimming cycle time

Core Design Contradiction:

Loss of substanceVSLoss of time

Solution Approach 1:

The edge trimming employs periodic cutting actions with regular intervals between steps. The cutting blade repeatedly engages and disengages the workpiece to form multiple stepped regions, achieving significant off-cut volume reduction while maintaining reasonable processing time through optimized periodic cycles.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Instead of removing the entire chamfered portion in one action, the process applies partial cuts at different depths to create stepped regions. This partial action approach reduces off-cut volume effectively while avoiding the time penalty of complete removal, striking an optimal balance between material reduction and processing efficiency.

Inventive Principle:

Principle #16Partial or excessive 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 method significantly reduces the volume and frequency of off-cuts, enhancing the efficiency of the grinding process and minimizing manual handling, while maintaining the integrity of the wafer during grinding.

Implementation Method 1

a cut in step of, after the holding step, relatively moving a rotating cutting blade and the chuck table to cause the cutting blade to cut into the outer peripheral portion of the workpiece

Methodology Applied

Scientific EffectMechanical cutting: Mechanical Force

Data Source

PatentUS20220184768A1Edge trimming method

Publication Date: 2022.06.16 DISCO CORP

AI summary

An edge trimming method for cutting an outer peripheral portion of a workpiece having a chamfered part on the outer peripheral portion. The method includes a cut in step of relatively moving a rotating cutting blade and a chuck table to cause the blade to cut into the outer peripheral portion, a cutting step of, after the cut in step, rotating the chuck table and causing the outer peripheral portion to be cut, to form an annular step, and a moving step of, after the cutting step, moving the blade in a direction of its axis of rotation to form another annular step adjacent to the first-mentioned annular step. The cut in, cutting, and moving steps are repeated in this order, and a stepped oblique region is formed on the outer peripheral portion, with a thickness increasing from an outermost peripheral edge toward an inner side of the workpiece.