Through-Silicon Via Formation Using Laser Ablation and Grinding

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Solution Overview

Problem

Conventional dry etching methods for forming through-silicon vias in silicon wafers are time-consuming and require photoresist coating and cleaning processes, which are not efficient for high output LED packages that need improved heat dissipation.

Innovation Solution

A method using laser ablation to form grooves in silicon wafers, followed by grinding to create through-silicon vias, eliminating the need for photoresist coating and cleaning, and utilizing ultrashort pulse lasers to minimize thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dry etching method is used to form through-silicon via, then etching can penetrate through silicon wafer, but process time is long and requires photoresist preparation

Engineering Contradiction:

Improvethrough-silicon via formation speedVSAvoidtotal process time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The through-silicon via formation process is segmented into two stages: first forming grooves to a depth of 70-90% of wafer thickness using laser ablation, then completing the through-hole by grinding from the opposite side. This segmentation allows each process to operate optimally without the limitations of single-method through-etching

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces the chemical etching mechanism of dry etching with laser ablation (optical energy field) to form grooves in the silicon wafer. This substitution eliminates the need for photoresist coating and chemical etching processes, directly achieving material removal through controlled laser irradiation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If dry etching method is used, then through-via can be formed, but photoresist coating and cleaning processes are required

Engineering Contradiction:

Improveprocess simplicityVSAvoidnumber of process steps

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts and removes the photoresist-related process steps (coating, patterning, and cleaning) from the through-silicon via formation process. By using laser ablation to directly form grooves without photoresist, the method eliminates these complex preparatory and cleanup steps, simplifying the overall manufacturing process

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The laser ablation process is self-directed and self-contained, requiring no external photoresist materials or subsequent cleaning processes. The laser beam directly ablates the silicon material to the desired depth, and the groove formation is complete without needing additional processing steps

Inventive Principle:

Principle #25Self-service

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

Simplifies the process of forming through-silicon vias by reducing processing time and avoiding photoresist-related steps, while maintaining high heat dissipation characteristics necessary for high output LED packages.

Implementation Method 1

laser drilling to form a plurality of grooves by irradiating a laser beam onto an upper surface of a silicon wafer

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

grinding a lower surface of the silicon wafer to form a plurality of through-silicon vias by exposing the grooves on the lower surface of the silicon wafer

Methodology Applied

Scientific EffectGrinding: Abrasion

Data Source

PatentUS8809189B2Method of forming through-silicon via using laser ablation

Publication Date: 2014.08.19 SAMSUNG ELECTRONICS CO LTD

AI summary

Methods of forming through-silicon vias by using laser ablation. A method includes, laser drilling to form a plurality of grooves by irradiating a laser beam onto an upper surface of a silicon wafer, and grinding a lower surface of the silicon wafer to form a plurality of through-silicon vias by exposing the grooves on the lower surface of the silicon wafer.