Substrate Thinning via Temporary Bonding Layer

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Solution Overview

Problem

The challenge in substrate thinning processes is achieving uniformity, as uneven supporting members can result in non-uniform substrate thinning, particularly when thinning substrates to extremely low thicknesses, which is critical for applications like surface acoustic wave technologies where precise thickness and flatness are required.

Innovation Solution

A temporary bonding layer with ultra-low total thickness variation is used between the substrate and the supporting member to provide a uniform baseline during the thinning process, ensuring even material removal and maintaining substrate flatness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a supporting member is used to enable handling and thinning of the substrate, then the substrate can be thinned to very small thickness, but the supporting member may be uneven or non-uniform causing non-uniform substrate thinning

Engineering Contradiction:
Improvesubstrate thickness uniformityVSAvoidsubstrate flatness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The supporting member is preprocessed to a specific and uniform thickness before the substrate thinning process begins. This preliminary action ensures that the baseline is even before the substrate is bonded and thinned, preventing the propagation of non-uniformity to the final substrate.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A bonding layer is introduced as an intermediary between the supporting member and the substrate. This bonding layer acts as a mediator that can compensate for minor non-uniformities in the supporting member while still providing adequate mechanical support during the thinning process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the substrate is thinned to extremely low thickness (one micron or less), then the upper frequency limits of SAW filters are increased, but the substrate becomes more susceptible to damage and requires precise uniformity

Engineering Contradiction:
Improveupper frequency limitVSAvoidsubstrate damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The supporting member is preprocessed to a specific and uniform thickness before the substrate thinning process begins. This preliminary action ensures that the baseline is even before the substrate is bonded and thinned, preventing the propagation of non-uniformity to the final substrate.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The uniform supporting member acts as a cushion or protective base during the thinning process. By providing a stable, pre-processed foundation, it cushions against the risks of substrate damage that would otherwise occur when handling and processing extremely thin substrates.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If the supporting member provides an even baseline for substrate processing, then uniform material removal is achieved, but the supporting member itself requires precise manufacturing

Engineering Contradiction:
Improvematerial removal uniformityVSAvoidsupporting member manufacturing
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The supporting member is preprocessed to a specific and uniform thickness before the substrate thinning process begins. This preliminary action ensures that the baseline is even before the substrate is bonded and thinned, preventing the propagation of non-uniformity to the final substrate.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A bonding layer is introduced as an intermediary between the supporting member and the substrate. This bonding layer acts as a mediator that can compensate for minor non-uniformities in the supporting member while still providing adequate mechanical support during the thinning process.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures that the substrate is thinned uniformly and to precise thickness, reducing the risk of damage and enhancing the performance of thin substrates in applications such as SAW technologies by maintaining consistent thickness and flatness.

Implementation Method 1

a bonding layer provides a temporary bond between the support substrate and the first substrate during a thinning process

Methodology Applied
Scientific EffectBonding: Adhesive

Data Source

PatentEP3993074A1Substrate thining using temporary bonding processes
Publication Date: 2022.05.04 CORNING INC
  • EP3993074A1 patent drawingFigure 1
  • EP3993074A1 patent drawingFigure 2A~2B
  • EP3993074A1 patent drawingFigure 3~4

AI summary

An article including a support unit, the support unit including a support substrate and a bonding layer such that the bonding layer is bonded to a surface of the support substrate. Furthermore, a total thickness variation TTV across a width of the support unit is about 2.0 microns or less.