Wafer Joining Adhesive Protrusion Control

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Solution Overview

Problem

The existing methods for joining semiconductor wafers with support substrates often result in adhesive protrusion, which can contaminate transfer and processing devices, leading to unsuitable joining of the substrates.

Innovation Solution

A method and system that includes a joining operation with an adhesive removal operation, where a solvent is supplied to the outside adhesive from the lateral side of the stacked substrate to remove the surface of the adhesive and form it to a predetermined size, preventing protrusion and ensuring proper substrate joining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the wafer and support substrate are pressed together using adhesive, then the joining strength is improved, but adhesive protrudes from the outer lateral side causing contamination

Engineering Contradiction:

Improvejoining strengthVSAvoidadhesive protrusion

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The adhesive application is segmented into two distinct stages: first applying adhesive to ensure proper joining strength, then separately removing the protruding portion through solvent treatment. This segmentation allows each function to be optimized independently without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protruding adhesive is removed in advance through solvent application before the joined substrates are transferred or processed further. This preliminary removal action prevents contamination of transfer devices and processing equipment, ensuring clean operations without affecting the already-formed bond strength.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If adhesive is applied generously to ensure complete coverage, then the reliability of joining is improved, but the adhesive protrusion increases causing device contamination

Engineering Contradiction:

Improvejoining reliabilityVSAvoiddevice contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solvent removal step is performed in advance as a preliminary action to eliminate protruding adhesive before the substrates are transferred or processed. This ensures that complete adhesive coverage for reliability is achieved without the harmful effect of protrusion causing device contamination.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The harmful protruding adhesive is extracted from the joined structure through solvent application and removal. This separates the beneficial adhesive coverage from the harmful protrusion, allowing the former to ensure reliability while the latter is eliminated to prevent device contamination.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If pressure is applied to ensure strong bonding, then the joining strength is improved, but adhesive is forced out from the gap causing protrusion

Engineering Contradiction:

Improvebonding strengthVSAvoidadhesive extrusion

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The bonding process is segmented into two independent operations: first applying pressure to achieve strong bonding, then separately removing the extruded adhesive through solvent treatment. This segmentation allows optimal pressure application for strength without the penalty of permanent adhesive extrusion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The adhesive extrusion that occurs during pressing, which would normally be a harmful effect, is converted into a benefit by using the extruded adhesive as material that can be selectively removed through solvent treatment. The extrusion provides access to the adhesive for solvent application, enabling clean removal without compromising the bonded joint.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively prevents adhesive protrusion, allowing for appropriate joining of the target and support substrates, thereby avoiding contamination of transfer and processing devices.

Implementation Method 1

supplying a solvent of the adhesive to an outside adhesive, which is the adhesive between the target substrate and the support substrate protruding in the joining operation from an outer lateral side of a stacked substrate made by joining the target substrate and the support substrate, to remove a surface of the outside adhesive

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS9463612B2Joining method and joining system

Publication Date: 2016.10.11 TOKYO ELECTRON LTD

AI summary

The present disclosure is a joining method that joins a target substrate and a support substrate, wherein the method has: a joining operation that includes pressing and joining the target substrate and the support substrate by interposing an adhesive therebetween; and an adhesive removing operation that includes supplying a solvent of the adhesive to the outer adhesive that is the adhesive between the target substrate and the support substrate protruding in the joining operation from the outer lateral surface of the stacked substrate made by joining the target substrate and the support substrate, and to remove the surface of the outer adhesive so that the outer adhesive is formed at a predetermined size.