Composite Wafer Separation Using Polymer-Filled Trenches

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Solution Overview

Problem

Current semiconductor wafer processing methods face challenges in efficiently separating semiconductor devices while minimizing damage and ensuring precise handling, particularly in maintaining the structural integrity of individual chips during the separation process.

Innovation Solution

The method involves forming trenches in non-device regions of a semiconductor wafer, filling them with a sacrificial material, and then thinning the wafer to expose the material, which is used to separate the devices by creating a composite structure that allows for mechanical and electrical isolation of individual chips, using polymer layers to encapsulate and stabilize the metallization structures, and applying additional metallization and polymer layers for enhanced separation and protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional dicing methods are used to separate semiconductor devices, then separation is achieved, but structural integrity of individual chips is compromised and damage occurs

Engineering Contradiction:
Improvestructural integrityVSAvoidseparation process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a sacrificial material layer as an intermediary between adjacent semiconductor devices. This sacrificial material is selectively removed to create separation, allowing chips to be divided without direct mechanical contact that would cause damage. The intermediary enables separation while preserving structural integrity by avoiding direct cutting forces on the chip edges.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the continuous semiconductor wafer into individual devices by removing sacrificial material in non-device regions. This creates discrete separation zones between devices, allowing each chip to be independently handled while maintaining its structural integrity. The segmentation is achieved through selective material removal rather than forceful division.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If polymer layers are applied to encapsulate metallization structures, then structural stability is improved, but process complexity increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The polymer layers serve multiple functions simultaneously: they provide structural stability to metallization structures, act as sacrificial material for separation, and serve as a protective encapsulation layer. This multi-functionality reduces the need for additional separate process steps, thereby managing complexity while achieving multiple objectives including structural stabilization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs composite material structures where polymer layers are combined with metallization layers and semiconductor substrates. These composite structures provide enhanced structural stability and mechanical strength to the metallization features during subsequent processing steps, while the integrated nature of the composite reduces overall process complexity compared to separate stabilization steps.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If trenches are formed and filled with sacrificial material, then separation precision is improved, but manufacturing steps increase

Engineering Contradiction:
Improveseparation precisionVSAvoidmanufacturing steps
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The sacrificial material is deposited into trenches in non-device regions before the semiconductor devices are fully processed or before separation is needed. This preliminary action establishes precise separation boundaries in advance, allowing subsequent processing steps to proceed without additional alignment or positioning operations, thereby maintaining precision while managing the number of critical steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the trench formation and sacrificial material deposition steps into the existing wafer fabrication process flow. By combining these separation-preparation steps with standard deposition and patterning processes already used for device fabrication, the precision separation is achieved without adding significant numbers of independent manufacturing steps, thus maintaining productivity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3424077B1Composite wafer, semiconductor device, electronic component and method of manufacturing a semiconductor device
Publication Date: 2024.04.17 INFINEON TECHNOLOGIES AG
  • EP3424077B1 patent drawingFigure 1A~1F
  • EP3424077B1 patent drawingFigure 2A~2F
  • EP3424077B1 patent drawingFigure 3A~3F

AI summary

In an embodiment, a method includes forming at least one trench in non-device regions of a first surface of a semiconductor wafer, the non-device regions being arranged between component positions, the component positions including device regions and a first metallization structure, applying a first polymer layer to the first surface of a semiconductor wafer such that the trenches and edge regions of the component positions are covered with the first polymer layer and such that at least a portion of the first metallization structure is uncovered by the first polymer layer, removing portions of a second surface of the semiconductor wafer, the second surface opposing the first surface, revealing portions of the first polymer layer in the non-device regions and producing a worked second surface and inserting a separation line through the first polymer layer in the non-device regions to form a plurality of separate semiconductor dies.