Fluid-Assisted Laser TSV Drilling With Minimal Heat Damage

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Solution Overview

Problem

Existing methods for producing through silicon via (TSV) face limitations such as anisotropic etching, low aspect ratio, and multiple photolithography steps, making them unsuitable for large-scale implementation.

Innovation Solution

A laser drilling method using fluid assistance and an artificial neural network (ANN) to simulate and predict optimal laser processing parameters, allowing for efficient production of TSV without the need for photolithography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If wet chemical etching or plasma dry etching is used to produce TSV, then the etching process can be performed, but anisotropic etching and low aspect ratio limitations occur

Engineering Contradiction:

ImproveTSV aspect ratioVSAvoidanisotropic etching

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces traditional mechanical/chemical etching systems with a laser-based processing system. The laser drilling method uses focused laser energy to ablate material and form TSV directly, eliminating the anisotropic etching problems and aspect ratio limitations inherent in wet chemical etching and plasma dry etching processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental processing parameter from chemical reaction-based etching to laser energy-based ablation. By controlling laser parameters such as pulse duration, power, and scanning speed, the system achieves superior TSV geometry with high aspect ratios and minimal anisotropic effects compared to traditional etching methods.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If multiple photolithography steps are used in TSV production, then the TSV structure can be formed, but the process complexity increases

Engineering Contradiction:

Improveprocess simplicityVSAvoidmultiple photolithography steps

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the photolithography steps from the TSV manufacturing process. The laser drilling system directly patterns and drills TSV through the substrate without requiring photoresist coating, photolithography exposure, or development steps, significantly simplifying the overall manufacturing process.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the multi-step photolithography system with a direct laser writing and drilling system. The laser system can directly write patterns and drill holes in a single integrated process, eliminating the need for separate photolithography equipment and multiple processing steps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If traditional TSV production methods are used, then the process can be implemented, but they are not suitable for large-scale implementation

Engineering Contradiction:

Improvelarge-scale implementation capabilityVSAvoidprocess scalability

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent implements continuous laser scanning and drilling operations that can process large areas of substrate without interruption. The laser system maintains continuous operation with high repetition rates, enabling high-volume production of TSV arrays across large substrates, which is essential for large-scale implementation.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent uses periodic pulsed laser operation with high repetition rates to achieve both precise material removal and high processing speed. The pulsed nature of the laser allows for controlled ablation while the high repetition rate enables rapid processing of multiple TSV holes in sequence, scaling the process for large-scale production.

Inventive Principle:

Principle #19Periodic 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

The method effectively produces TSV with high aspect ratio, minimal taper angle, and reduced heat-affected zone, enhancing processing quality and efficiency while being cost-effective.

Implementation Method 1

a laser applying step: applying a laser through the fluid and performing a laser processing on the substrate

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the laser processing comprises laser drilling, laser cutting, laser grooving, laser trimming, laser trenching

Methodology Applied

Scientific EffectAblation: Ablation

Data Source

PatentUS20250190770A1Method for processing substrate by using laser and system thereof

Publication Date: 2025.06.12 NAT CHENG KUNG UNIV

AI summary

The invention provides a method for processing a substrate by using laser, which includes: a substrate providing step, providing a substrate; a fluid applying step, applying a fluid on the substrate; and a laser applying step, applying a laser to the substrate under the fluid so as to perform a laser processing on the substrate, wherein the types of laser processing include drilling, cutting, grooving, trimming or trenching. At the same time, the present invention also discloses a system for processing a substrate by using laser. Through the selection of different fluid types, the present invention can achieve different laser processing effects so as to meet market demands.