Megasonic Cleaning Probe With Variable Cross-Section Protrusion

Solution Overview

Problem

Conventional megasonic cleaning processes for semiconductor wafers face challenges in uniformly distributing cleaning force across the wafer surface, leading to potential damage at the edge portions due to concentrated energy, as much of the energy dissipates along the cleaning probe, resulting in uneven cleaning effectiveness and risk of pattern lifting.

Innovation Solution

A megasonic cleaning apparatus with a cleaning probe featuring a protrusion between the rear and front portions, where the cross-section width of the protrusion is larger than the front portion, allowing for a uniform distribution of force across the wafer surface by acting as a damper and adjusting the bubble formation and bursting points to reduce the cleaning force at the edge, thereby preventing damage and ensuring consistent cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the force of megasonic waves is increased to provide adequate cleaning effect at center portion of wafer, then cleaning effectiveness at center is improved, but cleaning force at edge portion becomes excessively large causing pattern lifting damage

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidpattern lifting damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The cleaning probe is designed with variable cross-sectional area along its length, creating different local properties: a larger cross-section at the edge portion to reduce cleaning force and prevent damage, and a smaller cross-section at the center portion to concentrate cleaning force for effective particle removal. This local variation in geometry allows different regions of the wafer to receive appropriate cleaning force.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameter of the cleaning probe's cross-sectional area along its length. By gradually reducing the cross-sectional area from the edge portion to the center portion, the probe modifies how megasonic wave energy is distributed, creating a gradient in cleaning force that matches the different cleaning requirements of edge and center regions.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a conventional uniform cross-section cleaning probe is used, then the structure is simple and easy to manufacture, but the cleaning force is unevenly distributed across the wafer surface

Engineering Contradiction:

Improveprobe structure simplicityVSAvoiduniformity of cleaning force

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The cleaning probe is designed with variable cross-sectional area along its length, creating different local properties: a larger cross-section at the edge portion to reduce cleaning force and prevent damage, and a smaller cross-section at the center portion to concentrate cleaning force for effective particle removal. This local variation in geometry allows different regions of the wafer to receive appropriate cleaning force.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameter of the cleaning probe's cross-sectional area along its length. By gradually reducing the cross-sectional area from the edge portion to the center portion, the probe modifies how megasonic wave energy is distributed, creating a gradient in cleaning force that matches the different cleaning requirements of edge and center regions.

Inventive Principle:

Principle #35Parameter changes

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 ensures a uniform cleaning force across the entire wafer surface, reducing the risk of edge damage and enhancing cleaning effectiveness by dispersing the force uniformly, thus improving the overall cleaning process for semiconductor wafers.

Implementation Method 1

a piezoelectric transducer configured to generate megasonic waves

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The high frequency waves generated by the cleaning probe generate bubbles inside the fluid. As the bubbles impact and burst on the surface of the wafer, the resulting force—formed by the combination of bursting bubbles and fluid displacement

Methodology Applied

Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentUS7412982B2Cleaning probe and megasonic cleaning apparatus having the same

Publication Date: 2008.08.19 SAMSUNG ELECTRONICS CO LTD

AI summary

A cleaning probe capable of providing uniform cleaning to an entire wafer while not damaging the edge portion of the wafer, and a megasonic cleaning apparatus having the cleaning probe are provided. The cleaning probe comprises a front portion located near the center of the wafer, a rear portion connected to a piezoelectric transducer, and a protrusion located between the rear portion and the front portion, located on an edge portion of the wafer, and having a larger cross section width than the front portion.