Chuck Table Holding Plate Laser Cleaving for Wafer Parallelism

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Solution Overview

Problem

Conventional chuck tables fail to achieve high precision in making the holding surface parallel to the wafer surface due to material differences between the wafer and the chuck table, despite efforts to use matching materials.

Innovation Solution

A chuck table design featuring a holding plate with cleaved portions formed by laser processing, which transmits negative or positive pressure to the holding surface, allowing for precise alignment with the wafer surface, and a manufacturing method that includes providing a base material, forming modified layers, cleaving the material into blocks, and integrating the holding plate with a frame body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the material of the wafer and the material of the chuck table are made the same, then the parallelism between the holding surface and wafer surface is improved, but the manufacturing precision is still insufficient due to material differences alone

Engineering Contradiction:

Improveparallelism between holding surface and wafer surfaceVSAvoiduniformity of wafer thickness

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The holding plate is divided into multiple blocks through cleaved portions, creating a segmented structure that allows for more precise control of the holding surface geometry. This segmentation enables the surface to be formed with higher precision by assembling multiple precisely manufactured blocks

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical grinding or machining methods with laser beam processing to form modified layers and create cleaved portions. This optical method (laser) provides superior precision and control compared to conventional mechanical systems, enabling the holding surface to be formed with the required high precision parallelism

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables the holding surface of the chuck table to be formed parallel to the wafer surface with high precision, ensuring uniform thickness during grinding operations.

Implementation Method 1

applying a laser beam of a wavelength, which has transmissivity through the holding plate, with a focal point thereof positioned inside the holding plate

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

forming a plurality of modified layers by applying a laser beam

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 3

the negative pressure or the positive pressure is transmitted from the cleaved portions to the holding surface

Methodology Applied

Scientific EffectPressure transmission: Pressure Gradient

Implementation Method 4

a holding surface for holding the wafer under suction

Methodology Applied

Scientific EffectSuction: Suction

Data Source

PatentUS20230245914A1Chuck table and manufacturing method of chuck table

Publication Date: 2023.08.03 DISCO CORP

AI summary

A chuck table includes a holding plate having a holding surface for holding the wafer under suction, and a frame body that supports the holding plate thereon and transmits a negative pressure or a positive pressure to the holding surface. The holding plate is formed such that a plurality of cleaved portions are included through cleavage of the holding plate into a plurality of blocks along a plurality of modified layers formed by applying a laser beam of a wavelength, which has transmissivity through the holding plate, with a focal point thereof positioned inside the holding plate, and the negative pressure or the positive pressure is transmitted from the cleaved portions to the holding surface. A grinding machine and a manufacturing method of the chuck table for holding the wafer are also disclosed.