Beveled Saw Blade Singulation for IC Packaging

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Solution Overview

Problem

The singulation process of packaged integrated circuits during wafer level packaging often induces damage to the integrated circuit due to mechanical sawing through the molding compound and wafer, leading to chipping and delamination.

Innovation Solution

A method involving the use of a beveled saw blade to create a wide kerf that only partially cuts through the substrate, followed by a second thinner saw blade to complete the separation, minimizing mechanical stress and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single saw blade is used to cut through the molding compound and wafer, then the singulation process is simpler and faster, but mechanical damage and delamination increase

Engineering Contradiction:

Improvesingulation speedVSAvoidmechanical damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The singulation process is divided into two separate cutting operations: first cutting through the molding compound, then cutting through the wafer substrate. This segmentation allows each cutting operation to be optimized independently, reducing mechanical damage to the integrated circuits while maintaining productivity.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If mechanical sawing is applied to singulate packaged integrated circuits, then individual die can be separated, but chipping and delamination occur

Engineering Contradiction:

Improvesingulation capabilityVSAvoidcircuit integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The molding compound is cut through completely before cutting the wafer substrate. This preliminary action creates a gap and reduces stress on the integrated circuits during the subsequent wafer cutting operation, preventing chipping and delamination while maintaining singulation capability.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If conventional singulation methods are used, then the process is simpler, but stress distribution is uncontrolled leading to damage

Engineering Contradiction:

Improvesingulation process complexityVSAvoidstress control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The cutting parameters are changed by using two different saw blades with different thicknesses and properties. The first blade is optimized for cutting molding compound, while the second blade is optimized for cutting the wafer substrate. This parameter change allows controlled stress distribution, preventing damage while maintaining manageable process complexity.

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

This approach reduces mechanical damage and delamination by controlling the kerf dimensions and distribution of stress, allowing for more precise and damage-minimized singulation of integrated circuits.

Implementation Method 1

sawing through the molding compound and a top portion of the substrate using a beveled saw blade to form a wide kerf

Methodology Applied

Scientific EffectMechanical cutting: Abrasion

Implementation Method 2

sawing through a bottom portion of the substrate using a second thinner saw blade

Methodology Applied

Scientific EffectMechanical cutting: Abrasion

Data Source

PatentUS10964595B2Method for singulating packaged integrated circuits and resulting structures

Publication Date: 2021.03.30 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of packaging an integrated circuit includes forming a first integrated circuit and a second integrated circuit on a wafer, the first and second integrated circuit separated by a singulation region. The method includes covering the first and second integrated circuits with a molding compound, and sawing through the molding compound and a top portion of the wafer using a beveled saw blade, while leaving a bottom portion of the wafer remaining. The method further includes sawing through the bottom portion of the wafer using a second saw blade, the second saw blade having a thickness that is less than a thickness of the beveled saw blade. The resulting structure is within the scope of the present disclosure.