Wafer Division via Groove Initiation and Lateral Force

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Solution Overview

Problem

Existing wafer processing methods for dividing wafers into device chips using a cutting blade can deform and damage the side surfaces of the chips due to resistance from the mold resin during the cutting process.

Innovation Solution

A wafer processing method that forms a division start point at the lateral center of the mold resin filling the spacing between device chips, using a cutting blade, scriber, or laser processing to create a groove, and then applies an external force to laterally divide the chips, avoiding direct cutting with the blade.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a cutting blade is used to cut the mold resin filling each cut groove, then the wafer can be divided into individual device chips, but the cutting edge of the cutting blade may be deformed by the resistance of the mold resin, causing damage to the side surface of each device

Engineering Contradiction:

Improvewafer division efficiencyVSAvoidside surface quality of device chips

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The method forms a division start point (groove) at the lateral center of the mold resin filling the spacing between adjacent devices before performing the actual division. This preliminary groove serves as a stress concentration point that facilitates clean separation when external force is applied, preventing the cutting blade from directly contacting and damaging the device side surfaces

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces the direct mechanical cutting action with a combination of preliminary groove formation and external force application. Instead of using a cutting blade to directly cut through the mold resin and devices, the method uses a scriber or laser to create a division start point, then applies external force to propagate the separation, eliminating the harmful mechanical contact between the cutting blade and device side surfaces

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a cutting blade with thickness smaller than the width of each cut groove is used, then the blade can pass through the cut groove, but the resistance from the mold resin causes cutting edge deformation and device damage

Engineering Contradiction:

Improvecutting blade passage through grooveVSAvoidcutting edge deformation and device side surface damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The division start point groove acts as an intermediary structure that facilitates the separation process. By pre-forming this groove at the lateral center of the mold resin, the method creates a controlled separation path that guides the division process without requiring the cutting blade to directly contact and force its way through the mold resin, thereby eliminating cutting edge deformation and device damage

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The method extracts the harmful cutting action from the division process. Instead of using a cutting blade that physically contacts and damages the devices, the invention uses a scriber or laser to create a division start point groove, then applies external force to propagate separation. This extracts the damaging mechanical cutting interaction while retaining the functional outcome of wafer division

Inventive Principle:

Principle #2Taking out (Extraction)

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 method prevents deformation of the cutting blade and minimizes damage to the side surfaces of the device chips, ensuring high-quality chip production surrounded by mold resin.

Implementation Method 1

a division start point forming step of forming a division start point along each street at the lateral center of the mold resin filling the spacing

Methodology Applied

Scientific EffectLaser processing: Laser

Implementation Method 2

a dividing step of applying an external force to the wafer after performing the division start point forming step, thereby laterally dividing each street into two parts at the division start point

Methodology Applied

Scientific EffectMechanical force: Mechanical Force

Data Source

PatentUS9852949B2Wafer processing method

Publication Date: 2017.12.26 DISCO CORP

AI summary

A wafer is divided into device chips each of which is surrounded by a mold resin. The wafer has a plurality of devices arranged like a matrix with a spacing having a predetermined width, the front side of each device being covered with the mold resin, the spacing being filled with the mold resin to form a street between any adjacent ones of the devices. The wafer processing method includes a division start point forming step of forming a division start point along each street at the lateral center of the mold resin filling the spacing and a dividing step of applying an external force to the wafer after performing the division start point forming step, thereby laterally dividing each street into two parts at the division start point to obtain the device chips divided from each other, each device chip being surrounded by the mold resin.