Wafer Holder Suction Mechanism for Laser Cutting

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Solution Overview

Problem

Conventional wafer cutting methods face difficulties when processing wafers with high Moh's hardness materials, as laser processing damages the chuck table and causes protective tape to melt and adhere, complicating wafer handling and future use.

Innovation Solution

A wafer holding mechanism using a suction part on the wafer holder with open grooves to transmit suction force, made from materials like quartz or boro-silicated glass, which prevents damage from the laser and allows for secure holding without penetrating holes, and includes a light-emitting unit for precise cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a chuck table is used to suctionally hold the wafer, then the wafer can be held in place, but the laser beam damages the chuck table and causes protective tape to melt and adhere

Engineering Contradiction:

Improvewafer holding stabilityVSAvoidlaser beam damage to chuck table

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The suction function is segmented from the wafer holder body and placed in a separate suction unit positioned beneath the holder. The suction force is transmitted through the holder body rather than direct contact between the chuck table and wafer, isolating the holder from laser damage while maintaining holding stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The holder body acts as an intermediary medium that transmits suction force from the suction unit to the wafer. This allows the wafer to be held securely without the chuck table being exposed to the laser beam, preventing both table damage and tape melting.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If fine holes are formed in the wafer holder to transmit suction force, then the wafer can be held securely, but it becomes difficult to form holes in materials with high laser absorption

Engineering Contradiction:

Improvesuction holding effectivenessVSAvoiddifficulty of forming holes in holder material

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The suction transmission path is segmented into two parts: fine holes in the suction unit (easy to form) and a solid holder body (no holes needed). This eliminates the need to form holes in the holder material while maintaining effective suction transmission through the holder's outer peripheral edge.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The suction force transmission is shifted from a vertical path through the holder thickness to a horizontal path along the outer peripheral edge of the holder. This dimensional change allows suction to reach the wafer without penetrating holes through the holder material.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Use of energy by moving object

If the holder material has high laser absorption, then laser energy is absorbed, but it becomes difficult to form fine holes and the holder may overheat

Engineering Contradiction:

Improvelaser energy absorptionVSAvoiddifficulty of forming holes

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The system is segmented into a suction unit (with holes, made of easily manufacturable material) and a holder body (solid, made of laser-absorbing material). This allows each component to be optimized independently: the suction unit for manufacturability and the holder for laser energy absorption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The holder body serves as an intermediary that absorbs laser energy without requiring holes, while the suction unit separately provides the suction function. This mediator approach allows the use of high laser-absorption materials without the manufacturing constraints of hole formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Prevents wafer holder damage and tape melting, ensures strong and secure wafer holding, and allows for effective use of the space beneath the holder, facilitating precise cutting and handling of high-hardness wafers.

Implementation Method 1

a suction part formed on an outer peripheral side of the wafer holder, the wafer holding mechanism holding the wafer at the holding surface by a suction force transmitted to the holding surface from the suction part through an outer peripheral edge part of the wafer holder

Methodology Applied

Scientific EffectSuction: Suction

Implementation Method 2

a material of good permeability and dispersibility with respect to the wavelength of the laser beam can be selected for the wafer holder. As a result, damage to the wafer holder from the laser beam can be prevented, as can melting of tape affixed to the wafer

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS7557904B2Wafer holding mechanism

Publication Date: 2009.07.07 DISCO CORP

AI summary

A wafer holding mechanism for holding a wafer affixed to a frame with a tape utilizing a suction force. The wafer holding mechanism includes a suction body, a wafer holder with a holding surface for holding the wafer via the tape, and a suction unit with a suction portion disposed at an outer peripheral edge of the wafer holder. The suction portion transmits a suction force across the holding surface though the outer peripheral edge of the wafer holder such that when the suction portion is covered and sealed by the tape, the wafer holder is held at the suction unit and the wafer is held at the holding surface.