Semiconductor Wafer Rear Surface Electrode Formation Sequence

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Solution Overview

Problem

The existing methods for manufacturing semiconductor devices face issues with the formation of rear surface electrodes using physical vapor deposition methods, where the electrodes extend to the front surface, leading to peeling of plated films and abnormal deposition, resulting in reduced yield and potential chip defects due to the structural limitations of sputtering apparatus and warping of semiconductor wafers.

Innovation Solution

A method is introduced where the rear surface electrode is formed after thinning the semiconductor wafer and forming the front surface electrode, ensuring that the plated film is not deposited on the extended end of the rear surface electrode, thereby preventing peeling and abnormal deposition, and improving the yield by sequencing the electrode formation processes to prevent adhesion issues and reattachment of peeled films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the rear surface electrode is formed before thinning the semiconductor wafer using physical vapor deposition, then the electrode can be formed on the rear surface, but the electrode extends to the front surface causing plated film peeling and abnormal deposition

Engineering Contradiction:

Improveease of forming rear surface electrodeVSAvoidplated film integrity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The semiconductor wafer is thinned before forming the rear surface electrode. This preliminary thinning action prevents the electrode from extending to the front surface, thereby avoiding plated film peeling and abnormal deposition while still allowing the electrode to be formed on the rear surface.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If the plated film is formed on the front surface electrode before forming the rear surface electrode, then the front surface electrode can be plated, but the plated film peels off when the rear surface electrode extends to it

Engineering Contradiction:

Improveplated film thickness consistencyVSAvoidchip defect rate

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The semiconductor wafer is thinned before forming the rear surface electrode, which prevents the electrode from extending to the front surface and peeling the plated film. This preliminary thinning action ensures plated film integrity and prevents chip defects.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The conventional sequence is inverted: instead of forming the rear surface electrode first and then thinning the wafer, the wafer is thinned first and then the rear surface electrode is formed. This inversion prevents the electrode from extending to the front surface and peeling the plated film.

Inventive Principle:

Principle #13The other way round (Inversion)

3Length of stationary object

If the semiconductor wafer is not thinned before forming the rear surface electrode, then the wafer maintains its original thickness, but the rear surface electrode extends to the front surface causing manufacturing defects

Engineering Contradiction:

Improvewafer thicknessVSAvoidelectrode positioning accuracy

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The semiconductor wafer is thinned before forming the rear surface electrode. This preliminary thinning action ensures that the electrode is formed only on the rear surface without extending to the front surface, thereby maintaining electrode positioning accuracy and preventing manufacturing defects.

Inventive Principle:

Principle #10Preliminary action

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 allows for the high-yield manufacturing of semiconductor devices by preventing peeling and abnormal deposition, reducing chip defects, and ensuring consistent plating film thickness, thereby enhancing the reliability and efficiency of the semiconductor device production process.

Implementation Method 1

a rear surface of the semiconductor wafer is ground to reduce a thickness of the semiconductor wafer

Methodology Applied

Scientific EffectGrinding: Abrasion

Implementation Method 2

a front surface electrode layer is plated to form a front surface electrode

Methodology Applied

Scientific EffectPlating: Electroplating

Implementation Method 3

a rear surface electrode is formed on the ground rear surface of the semiconductor wafer

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS9666437B2Method for manufacturing semiconductor device

Publication Date: 2017.05.30 FUJI ELECTRIC CO LTD

AI summary

A method for manufacturing a semiconductor device including a semiconductor chip having a front surface electrode and a rear surface electrode provided on a front surface and a rear surface, respectively, the method includes a front surface electrode layer forming step of forming a front surface electrode layer as the front surface electrode on a front surface of a semiconductor wafer forming the semiconductor chip; a thinning step of grinding a rear surface of the semiconductor wafer to reduce a thickness of the semiconductor wafer after the front surface electrode layer forming step; a plating step of forming an electrode plating film as the front surface electrode on a surface of the front surface electrode layer after the thinning step; and a rear surface electrode forming step of forming the rear surface electrode on the ground rear surface of the semiconductor wafer after the plating step.