Laser Ablation of Conductive Seed Layers
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Solution Overview
Problem
Conventional methods for removing surplus conductive seed layers from electronics substrates, such as wet chemical, dry chemical, and plasma etch processes, are limited by their inability to produce finer pitch structures, cause undercutting, leave contaminants, increase costs, and are environmentally unfriendly.
Innovation Solution
The use of laser ablation systems to selectively remove surplus seed layers by irradiating the substrate with laser light, avoiding damage to the underlying conductive structures and eliminating the need for harsh chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wet chemical, dry chemical, or plasma etch processes are used to remove surplus seed layers, then the seed layer removal can be achieved, but the process prevents the formation of finer pitch structures, causes undercutting and contamination, increases costs, and is environmentally unfriendly
Solution Approach 1:
The patent replaces chemical etching processes with laser ablation technology. The laser beam directly ablates the surplus seed layer through photothermal effects, eliminating the need for chemical solutions that cause undercutting and contamination. This substitution enables precise removal of seed layers while maintaining the integrity of adjacent conductive structures, thereby achieving finer pitch structures without the harmful side effects of conventional chemical processes.
Solution Approach 2:
The patent utilizes controlled laser parameters (wavelength, pulse duration, fluence) to selectively remove surplus seed layers. By adjusting these parameters, the process achieves precise control over the ablation depth and lateral spread, enabling the formation of finer pitch structures while preventing undercutting. The laser parameters are optimized to differentiate between the seed layer and the conductive structures, allowing selective removal without contamination.
2Productivity
If conventional etch processes are used, then seed layer removal is achieved, but process times are increased and equipment costs are higher
Solution Approach 1:
The patent replaces complex chemical etching equipment and multi-step methodologies with a laser ablation system. The laser process integrates seed layer removal into a single step, eliminating the need for multiple chemical baths, rinsing steps, and drying processes. This substitution reduces overall process time while simplifying the equipment required, as the laser system can be directly integrated into existing semiconductor manufacturing lines.
Solution Approach 2:
The laser ablation process enables continuous removal of surplus seed layers as the laser beam scans across the substrate. This continuous action eliminates the intermittent steps required in conventional chemical etching (application, waiting, rinsing, repeating), thereby reducing total process time while maintaining high precision. The laser can process multiple substrates in sequence without requiring intermediate processing steps.
3Ease of manufacture
If conventional etch processes are used, then seed layer removal is achieved, but environmental harm increases due to harsh chemicals
Solution Approach 1:
The patent replaces chemical-based etching processes with laser ablation, eliminating the use of harsh chemicals entirely. The laser beam removes material through controlled vaporization and ejection, producing no chemical waste streams. This substitution simplifies the manufacturing process by eliminating chemical handling, storage, and disposal requirements, while simultaneously eliminating environmental contamination from etch chemicals and their byproducts.
Solution Approach 2:
The patent converts the laser's high energy input, which could potentially damage the substrate, into a beneficial selective ablation process. By carefully controlling laser parameters, the energy is precisely confined to remove only the surplus seed layer without affecting the underlying substrate or adjacent conductive structures. This transforms what could be a harmful effect (high energy input) into a precise and clean removal process with no environmental harm.
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
Laser ablation enables the production of finer pitch structures with improved yield and reliability, reduces manufacturing costs, and is more environmentally friendly by avoiding chemical usage and allowing metal recycling.
Implementation Method 1
irradiating the surface with laser light (e.g., a fluence of laser light) effective to ablate the surplus seed layer from the surface
Data Source
AI summary
Various techniques are disclosed for an apparatus and a method to remove a layer from a substrate having a pattern formed on the layer. In one example, the apparatus comprises a stage configured to receive and hold the substrate. The apparatus may further comprise an irradiating device comprising a projection lens and configured to irradiate the surface of the substrate with pulses of laser light having a selected fluence to remove an interstitial portion of the layer between the pattern without removing the pattern for corresponding irradiated areas of the substrate. The pulses of laser light may be focused through the projection lens, and the stage and the projection lens may be configured to move continuously relative each other to irradiate a plurality of areas of the substrate with the pulses of laser light.