Semiconductor Dicing Stress Management via Delayed Curing

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Solution Overview

Problem

The existing semiconductor device manufacturing methods face challenges in performing a proper cutting process due to increased film stress and warping of semiconductor wafers caused by the thermal history of the protective film curing process, making it difficult to cut out semiconductor elements accurately.

Innovation Solution

A semiconductor device manufacturing method that involves preparing a semiconductor substrate with semiconductor element structures, affixing it to a dicing tape, forming a groove, applying a protective film precursor solution, roughly drying it to form a protective film, cutting along the groove, peeling the semiconductor elements, and performing full-curing after separation to avoid warping and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If full-curing of the protective film is performed before dicing, then the protective film provides surface protection, but film stress increases due to thermal history causing wafer warping that makes cutting difficult

Engineering Contradiction:

Improvesurface protectionVSAvoidcutting precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The protective film is applied before the dicing process, but full-curing is delayed until after cutting. The film is applied in a preliminary state that provides surface protection during manufacturing, then cured completely after the precision cutting is performed, avoiding thermal warping during the cutting process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The curing process is segmented into two stages: a preliminary application stage where the protective film is applied before dicing to provide surface protection, and a final full-curing stage performed after cutting. This segmentation allows the protective function to be available early while the precision cutting is performed on a flat, uncured wafer.

Inventive Principle:

Principle #1Segmentation

2Reliability

If full-curing is performed early, then the protective film achieves maximum protection, but thermal history causes increased film stress and wafer warping

Engineering Contradiction:

Improveprotective film protectionVSAvoidwafer flatness

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The protective film is applied in a preliminary state before full-curing to provide immediate surface protection during subsequent manufacturing steps, while the wafer remains flat for precise cutting. Full-curing is performed as a final action after the wafer shape is established through cutting.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The conventional sequence is inverted: instead of curing the protective film before cutting, the film is applied uncured before cutting, and full-curing is performed after cutting. This inversion allows the wafer to be cut while maintaining flatness, then cured to achieve maximum protection.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If protective film is applied before cutting, then surface protection is provided during manufacturing, but cutting becomes difficult due to warping

Engineering Contradiction:

Improvesurface protection during manufacturingVSAvoidcutting process ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protective film is applied in a preliminary uncured state before dicing to provide surface protection during handling and manufacturing, but full-curing is delayed until after cutting. This allows the cutting process to be performed easily on a flat wafer while still having protective coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The physical state of the protective film is changed from uncured (flexible, non-stressful) to fully cured (rigid, protective) at different stages. Before cutting, the film is in an uncured parameter state that allows easy manufacturing, then transformed to a fully cured state after cutting for maximum protection.

Inventive Principle:

Principle #35Parameter changes

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 method allows for proper cutting and separation of semiconductor elements while reducing film stress and warping, improving productivity and maintaining the quality of the semiconductor elements by applying the protective film precursor solution before cutting and curing.

Implementation Method 1

roughly drying a solvent in the protective film precursor solution to form a protective film

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

performing, after the process (g) or the process (h), full-curing to evaporate a solvent in the protective film

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11302538B2Semiconductor device manufacturing method

Publication Date: 2022.04.12 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor device manufacturing method includes processes of: applying a protective film precursor solution over an end of each of a plurality of semiconductor element structures and a side surface and a bottom surface of a groove; roughly drying a solvent in the protective film precursor solution to form a protective film; and performing full-curing to evaporate a solvent in the protective film after a process of cutting between the plurality of semiconductor element structures or a process of peeling a plurality of semiconductor elements from a dicing tape.