Wafer Protective Sheet with Cushioning Layer

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Solution Overview

Problem

In semiconductor device fabrication, protective films or sheeting can damage or contaminate sensitive devices due to adhesive forces or residues, especially when processing wafers with uneven surface structures like MEMS, during grinding and cutting steps, leading to increased risk of breakage and deformation.

Innovation Solution

A protective sheeting with a cushioning layer and no adhesive on its surfaces, applied to the wafer to prevent direct contact with adhesives, using heat to attach and detach securely, ensuring no adhesive residue remains on the wafer surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a protective film with adhesive layer is applied to protect the wafer during processing, then the wafer is protected from breakage and deformation, but the adhesive force or adhesive residues may damage or contaminate sensitive devices on the wafer

Engineering Contradiction:

Improveprotection from breakage and deformationVSAvoidadhesive damage and contamination to devices

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The protective film is divided into two distinct layers: a lower adhesive layer for securing the film to the wafer, and an upper non-adhesive protective layer that directly contacts the devices. This segmentation allows the film to provide mechanical protection without exposing devices to harmful adhesive substances.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The non-adhesive upper layer acts as an intermediary between the adhesive lower layer and the sensitive devices. It transmits the protective function while blocking the harmful adhesive force and residues from reaching the devices, thus mediating between the need for secure attachment and device safety.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If the wafer is ground to a small thickness to reduce device size, then the electronic equipment size is reduced, but the protrusions on the wafer surface may cause deformation of the wafer back side

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer back side deformation

Core Design Contradiction:

Length of moving objectVSShape

Solution Approach 1:

The non-adhesive upper layer of the protective film serves as a cushioning layer applied beforehand to the wafer surface. It absorbs and distributes the mechanical stress during grinding, preventing the protrusions from causing deformation of the wafer back side while allowing the wafer to be ground to the required small thickness.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a protective film is applied to protect devices during grinding and cutting, then device protection is improved, but the processing efficiency may be reduced due to additional steps

Engineering Contradiction:

Improvedevice protection during processingVSAvoidprocessing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The protective film combines multiple functions in a single structure: the lower layer provides adhesive attachment to secure the film during processing, while the upper layer provides non-adhesive protection against mechanical damage and contamination. This merging of functions into one integrated component streamlines the process compared to using separate protective measures.

Inventive Principle:

Principle #5Merging (Combining)

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 solution minimizes the risk of contamination and damage to the wafer devices by eliminating adhesive contact, allowing for reliable and efficient processing while maintaining the integrity of the wafer surface during grinding and cutting.

Implementation Method 1

using heat to attach and detach securely

Methodology Applied

Scientific EffectHeat: Heating

Implementation Method 2

A protective sheeting with a cushioning layer and no adhesive on its surfaces

Methodology Applied

Scientific EffectCushioning: Damping

Data Source

PatentUS11676833B2Protective sheet for use in processing wafer, handling system for wafer, and combination of wafer and protective sheeting

Publication Date: 2023.06.13 DISCO CORP

AI summary

A protective sheeting for use in processing a semiconductor-sized wafer includes a protective film and a cushioning layer attached to a back surface of the protective film. At least in a central area of the protective sheeting, no adhesive is applied to a front surface and a back surface of the protective sheeting, the central area having an outer diameter which is equal to or larger than an outer diameter of the semiconductor-sized wafer. Further, a protective sheeting for use in processing a wafer has a protective film and a cushioning layer attached to a back surface of the protective film, wherein, on an entire front surface and an entire back surface of the protective sheeting, no adhesive is applied. A handling system for a semiconductor-sized wafer and to a combination of a wafer and the protective sheeting are also described.