Femtosecond Laser Wafer Dicing With Plasma Etch for Clean Die Edges

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for dicing semiconductor wafers, such as scribing and sawing, often result in chipping, cracking, and waste of wafer real estate due to the limitations of mechanical separation techniques, and plasma dicing faces challenges with cost and metal processing issues.

Innovation Solution

A hybrid method combining femtosecond-based laser scribing and plasma etching is used to singulate integrated circuits, where a mask is patterned with a femtosecond laser to expose regions between circuits, followed by a plasma etch process to etch through the wafer, minimizing thermal damage and enabling precise control over the dicing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional scribing or sawing methods are used for wafer dicing, then the wafer can be separated into individual dice, but chipping and cracking occur along the severed edges and wafer real estate is wasted due to required spacing

Engineering Contradiction:

Improvewafer dicing efficiencyVSAvoidedge quality of diced dice

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces mechanical scribing and sawing systems with a laser-based system. A laser beam is used to scribe the wafer along predetermined streets, eliminating the mechanical contact that causes chipping and cracking. The laser energy selectively removes material through ablation without the physical stress of diamond-tipped tools, thereby improving edge quality while maintaining dicing efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If wider spacing is provided between dice to prevent damage from scribing or sawing, then chipping and cracking are reduced, but wafer real estate is wasted and fewer dice can be formed

Engineering Contradiction:

Improvedamage prevention to integrated circuitsVSAvoidusable wafer area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

By substituting mechanical dicing with laser scribing, the patent eliminates the need for wide spacing between dice. The laser beam can precisely follow the crystal lattice structure without causing damage to adjacent dice, allowing dice to be placed closer together and maximizing the usable wafer area while maintaining high reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If a diamond saw is used for dicing thicker wafers, then the wafer can be cut through, but the blade thickness and required spacing waste significant wafer real estate

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer real estate

Core Design Contradiction:

Length of moving objectVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanical diamond saw with a laser-based scribing system. The laser beam can penetrate and scribe through thicker wafers without the physical constraints of blade thickness. This eliminates the need for wide spacing around the cut path, allowing more efficient use of wafer real estate while maintaining the ability to dice thick wafers effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If conventional dicing methods are used, then separation of dice is achieved, but substantial cleaning is required to remove particles and contaminants

Engineering Contradiction:

Improvedicing process completionVSAvoidcleaning complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical sawing with laser scribing, which produces a cleaner cut with minimal debris. The laser ablation process vaporizes material rather than mechanically grinding it, significantly reducing the amount of particles and contaminants generated. This eliminates or greatly reduces the subsequent cleaning steps required, simplifying the manufacturing process while maintaining complete dice separation.

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

This approach reduces microcrack formation, delamination, and chipping, allowing for denser packing of integrated circuits on the wafer with reduced waste, improved process quality, and cost-effective implementation.

Implementation Method 1

patterning the mask with a femtosecond-based laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

etching the semiconductor wafer through the gaps in the patterned mask to singulate the integrated circuits

Methodology Applied

Scientific EffectPlasma etching: Plasma

Data Source

PatentUS20250022755A1Wafer dicing using femtosecond-based laser and plasma etch

Publication Date: 2025.01.16 APPLIED MATERIALS INC

AI summary

Methods of dicing semiconductor wafers, each wafer having a plurality of integrated circuits, are described. A method includes forming a mask above the semiconductor wafer, the mask including a layer covering and protecting the integrated circuits. The mask and a portion of the semiconductor wafer are patterned with a laser scribing process to provide a patterned mask and to form trenches partially into but not through the semiconductor wafer between the integrated circuits. Each of the trenches has a width. The semiconductor wafer is plasma etched through the trenches to form corresponding trench extensions and to singulate the integrated circuits. Each of the corresponding trench extensions has the width.