Cut Groove Depth Control for Low-k Film Flaking Prevention

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Solution Overview

Problem

Existing methods for cutting semiconductor wafers with low-dielectric-constant insulating films tend to cause flaking due to the brittleness of these films, and previous solutions either require expensive laser processing or result in inaccurate groove depths if the incision depth is not correctly set.

Innovation Solution

A method involving a cutting blade that forms preliminary cut grooves in a workpiece to determine a relational expression for groove depth and width, allowing for accurate depth calculation and correction to prevent flaking, using a combination of measurement and image capture to adjust the incision amount for precise cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If laser dicing is used to prevent low-k film flaking, then the low-k film flaking problem is solved, but the apparatus cost increases significantly

Engineering Contradiction:

Improvelow-k film flaking preventionVSAvoidapparatus cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the laser processing system with a mechanically controlled cutting blade system. The cutting blade is equipped with depth control mechanisms including a depth stop member and position detection means that mechanically limit the cutting depth to prevent low-k film flaking, eliminating the need for expensive laser equipment while solving the flaking problem.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a simple, inexpensive cutting blade with a limited lifespan (which wears out and needs replacement) instead of expensive laser equipment. The blade includes basic depth control features that are cost-effective but require periodic replacement, trading long-term equipment investment for consumable blade costs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Productivity

If the incision depth is increased to ensure complete cutting, then the cutting effectiveness is improved, but the groove width increases and devices may be removed

Engineering Contradiction:

Improvecutting effectivenessVSAvoidgroove width control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements preliminary depth control by providing a depth stop member that is set before cutting begins. This depth stop member mechanically limits the maximum incision depth, ensuring that the cutting blade does not cut too deep and remove devices, while still allowing sufficient depth for effective cutting.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent incorporates position detection means that provide feedback on the cutting blade's depth position. This feedback mechanism allows the control system to monitor and adjust the cutting depth in real-time, maintaining precise groove width control while ensuring complete cutting effectiveness.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the incision depth is decreased to maintain groove width precision, then device removal is prevented, but the cutting completeness may be compromised

Engineering Contradiction:

Improvegroove width controlVSAvoidcutting completeness

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The depth stop member is pre-configured with the optimal cutting depth value before the cutting process begins. This preliminary setting ensures that the blade cuts to the precise depth needed for complete separation while maintaining groove width precision, eliminating the need for real-time depth adjustments.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cutting system dynamically adjusts the blade depth based on the workpiece thickness detection. The position detection means and control system work together to optimize the cutting depth for each specific workpiece, ensuring both complete cutting and precise groove width control adaptively.

Inventive Principle:

Principle #15Dynamics

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

Enables the formation of cut grooves to an accurate depth along projected dicing lines, preventing low-k film flaking and ensuring precise cutting without the need for additional costly equipment, while maintaining the integrity of the semiconductor devices.

Implementation Method 1

a cutting blade having a cutting edge which is made of a superabrasive such as diamond, CBN, or the like bound together by metal or resin

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS10773410B2Method of forming cut groove

Publication Date: 2020.09.15 DISCO CORP

AI summary

A cut groove having a predetermined depth is formed with a cutting blade along a projected dicing line set on a workpiece. A first preliminary groove is cut in a measurement member and a relational expression with respect to a distance from the preliminary groove bottom and the width of the preliminary groove is determined. An amount of incision into the workpiece is set to be equal to or smaller than a predetermined value from a reference position and the thickness of the workpiece. A second preliminary groove is cut along the projected dicing line, and an image of the second preliminary cut groove is captured. The width of the second preliminary cut groove is measured, and the depth of the second preliminary cut groove is calculated from the width of the second preliminary groove and the relational expression.