Wafer Protection Layers for Dicing Yield

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Solution Overview

Problem

The challenge in semiconductor chip production is the contamination and scratching of wafer surfaces during the dicing and packaging process, leading to defects and reduced yield due to environmental moisture, dust, and debris, which increases production costs and discards valuable chips.

Innovation Solution

A method involving the application of two curing-type protection layers, one on the active surface and one on the reverse surface of the wafer, along with a pellicle, to protect the chips during the packaging process. The first curing-type protection layer is applied over the active surface, followed by a pellicle, and then both are cured, while the second curing-type protection layer is applied to the reverse surface, enhancing chip protection and yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wafer is cut through pre-cut trenches to separate chips during dicing, then chip production efficiency is improved, but wafer surface is scratched and contaminated by dust and debris

Engineering Contradiction:

Improvechip production efficiencyVSAvoidsurface scratching and contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A protection layer is formed on the wafer surface before the dicing process. This preliminary protective measure prevents scratching and contamination during the subsequent cutting operation, allowing efficient dicing without compromising chip surface integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer acts as an intermediary between the dicing blade and the wafer surface. It absorbs the mechanical stress and contamination during cutting, protecting the actual chip surfaces from direct contact with harmful factors while maintaining production efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If wafer surface is protected during dicing and packaging, then chip yield is improved, but additional protection layers and processes are required

Engineering Contradiction:

Improvechip yieldVSAvoidprotection layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protection layer uses a curing-type material that transitions from a liquid or paste state to a solid state through UV irradiation or heating. This parameter change allows the material to be easily applied in a fluid form and then transformed into a durable protective layer, simplifying the overall process despite the added protection function.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The protection layer undergoes phase transition during curing, changing from a soft, easily applicable state to a hard, protective state. This phase change enables simple application followed by robust protection, achieving high chip yield without excessively complex processing equipment.

Inventive Principle:

Principle #36Phase transitions

3Object-affected harmful factors

If curing-type protection layers are applied on both active and reverse surfaces, then protection effectiveness is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improveprotection effectivenessVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The protection process is segmented into two independent steps: applying protection layer on the active surface, and applying protection layer on the reverse surface. This segmentation allows each surface to be treated separately and independently, simplifying the manufacturing process while achieving comprehensive protection against various harmful factors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The same curing-type material and application method are used for both the active surface and reverse surface protection. This universal approach simplifies manufacturing by using identical materials and processes for both surfaces, reducing the need for different specialized procedures while maintaining high protection effectiveness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively prevents defects caused by dust, pollution, and scratching, enhancing the production yield of packaged chips by ensuring the integrity of the chip surfaces and reducing the risk of warpage and laser damage during the cutting and marking processes.

Implementation Method 1

a first curing-type protection layer and a second curing-type protection layer are cured

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS7510909B2Fabricating method of wafer protection layers

Publication Date: 2009.03.31 ADVANCED SEMICON ENG INC

AI summary

A fabricating method of wafer protection layers and a wafer structure are provided. The fabricating method includes providing a wafer first. The wafer includes pluralities of chips and has an active surface, a corresponding reverse surface and a plurality of pre-cut trenches on the active surface. On the active surface, pluralities of bumps are disposed. Next, a first curing-type protection layer and a pellicle are disposed over the active surface. Afterwards, the first curing-type protection layer is asked to contact the active surface. Besides, a second curing-type protection layer is disposed on the reverse surface. Afterward, the first and the second curing-type protection layer are cured. Finally, the wafer is cut through the pre-cut trenches to separate the chips from the wafer.