Wafer Segmentation for Low-Profile Flexible ICs

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Solution Overview

Problem

Manufacturing integrated circuits on thin wafers results in high costs and material waste due to the fragility of thin wafers and the need for additional processing steps, such as backgrinding or using carrier wafers, which also alter the electrical characteristics of the devices.

Innovation Solution

A method involving the deposition of a protective layer, etching of vias, and isotropic etching to release a top portion of the wafer with the integrated circuit, allowing for low-profile devices with minimal alteration to existing manufacturing processes and enabling recycling of the remaining wafer for further circuit production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If thin wafers are used for manufacturing integrated circuits, then device profile is reduced and flexibility is improved, but manufacturing yield deteriorates due to wafer fragility

Engineering Contradiction:

Improvewafer thicknessVSAvoidmanufacturing yield

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The wafer is segmented into a thin device portion and a thick support portion through selective thinning and release processes. The thin portion provides the desired low-profile and flexibility, while the thick support portion maintains structural integrity during manufacturing, resolving the contradiction between thinness and fragility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A carrier wafer acts as an intermediary substrate during the manufacturing process, providing mechanical support to the thin wafer. This intermediary structure allows thin wafers to be handled and processed without breaking, enabling low-profile devices while maintaining manufacturing yield.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If backgrinding is used to reduce wafer thickness, then device profile is reduced, but material waste increases and manufacturing cost increases

Engineering Contradiction:

Improvewafer thicknessVSAvoidmaterial waste

Core Design Contradiction:

Volume of moving objectVSLoss of substance

Solution Approach 1:

Instead of removing material through backgrinding, the wafer is segmented by selectively thinning only the necessary regions and releasing the thin portion from the thick support portion. This preserves the bulk material for potential reuse, reducing material waste while achieving the desired thin profile.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thick support portion of the wafer, which remains after the thin device portion is released, can be recovered and reused for subsequent device fabrication. This recovery process significantly reduces material waste compared to conventional backgrinding methods that destroy the entire wafer.

Inventive Principle:

Principle #34Discarding and recovering

3Stability of the object's composition

If carrier wafers are used to support thin wafers, then manufacturing stability is improved, but manufacturing complexity increases and additional processing steps are required

Engineering Contradiction:

Improvewafer stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The support structure is merged with the device wafer itself through the selective thinning and release process, eliminating the need for separate carrier wafers. This integration reduces manufacturing complexity while maintaining the necessary stability during processing.

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 approach reduces material waste, maintains the electrical properties of conventional semiconductor wafers, and allows for the production of low-profile integrated circuits suitable for mobile devices and flexible electronics while minimizing additional processing steps and costs.

Implementation Method 1

deposition of a protective layer

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

etching of vias

Methodology Applied

Scientific EffectEtching:

Implementation Method 3

isotropic etching to release a top portion of the wafer

Methodology Applied

Scientific EffectIsotropic etching:

Data Source

PatentUS9209083B2Integrated circuit manufacturing for low-profile and flexible devices

Publication Date: 2015.12.08 KING ABDULLAH UNIV OF SCI & TECH

AI summary

A process for manufacturing low-profile and flexible integrated circuits includes manufacturing an integrated circuit on a wafer having a thickness larger than the desired thickness. After the integrated circuit is manufactured the integrated circuit may be released with a portion of the wafer leaving a remainder of the bulk portion of the wafer. A second integrated circuit may be manufactured on the remainder of the wafer and the process repeated to manufacture additional integrated circuits from a single wafer. The integrated circuits may be released from the wafer by etching vias through the integrated circuit and into the wafer. The via may be used to start an etch process inside the wafer that undercuts the integrated circuit separating the integrated circuit from the wafer.