Tunable Laser Ablation for Precise Semiconductor Package Vias
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Solution Overview
Problem
Conventional laser drilling methods for forming vias in semiconductor substrates lack precise control of depth and topography, leading to inefficient energy use and low ablation rates.
Innovation Solution
A diode-pumped solid-state laser system with tunable parameters, including pulse energy, width, and frequency, combined with a large angle galvanometer optical scanner and telecentric lens, is used to form features in semiconductor packages with controlled depth and topography, utilizing a synchronized adjustable stage and controller for precise patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser drilling is used to form vias in semiconductor substrates, then the drilling speed is fast and positional accuracy is good, but the control of depth and topography is imprecise and energy efficiency is low
Solution Approach 1:
The patent applies periodic pulsed laser action instead of continuous laser drilling. The laser operates in pulsed mode with controlled pulse duration, frequency, and duty cycle to achieve precise depth control while improving energy efficiency. The pulsed operation allows thermal diffusion between pulses, preventing excessive heat accumulation and enabling better topography control.
Solution Approach 2:
The patent implements dynamic adjustment of laser parameters including pulse duration (1 ns to 4000 ns), pulse frequency (1 kHz to 200 kHz), and duty cycle (1% to 99%). These parameter changes enable optimization of the ablation process for different materials and desired via characteristics, achieving both precise depth control and improved energy efficiency.
2Productivity
If conventional laser drilling is used to form vias in semiconductor substrates, then the drilling speed is fast and positional accuracy is good, but the ablation rate is low
Solution Approach 1:
The patent employs dynamic control of laser parameters during the drilling process. The pulse duration, frequency, and duty cycle are adjusted in real-time based on the drilling depth and material properties. This dynamic adaptation maximizes the ablation rate while maintaining energy efficiency by optimizing the energy delivery at each stage of the drilling process.
Solution Approach 2:
The system changes laser parameters dynamically to optimize ablation rate. By adjusting pulse duration from 1 ns to 4000 ns and frequency from 1 kHz to 200 kHz, the system adapts to different drilling stages and material conditions, achieving higher ablation rates without proportional increases in energy consumption.
3Quantity of substance
If high density of semiconductor devices is achieved by stacking dies to create 3-D MCM, then the device density increases, but the complexity of via formation and interconnection increases
Solution Approach 1:
The patent replaces conventional mechanical drilling methods with laser-based ablation. This substitution eliminates the need for mechanical contact and tool changes, enabling direct formation of vias through multiple die layers with precise depth control. The laser method simplifies the overall process for creating complex 3-D interconnections in stacked die configurations.
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
Enables rapid and accurate formation of high-density features with controlled dimensions and smooth inner walls, enhancing semiconductor package fabrication efficiency and reducing material waste.
Implementation Method 1
a diode-pumped solid-state laser source having a slab gain medium and configured to generate a pulsed laser beam
Implementation Method 2
diode-pumped solid-state laser source
Implementation Method 3
systems and methods for forming features on packages by laser ablation
Implementation Method 4
rapid and accurate formation of high-density features with controlled dimensions and smooth inner walls
Data Source
AI summary
The present disclosure relates to systems and methods for fabricating semiconductor packages, and more particularly, for forming features in semiconductor packages by laser ablation. In one embodiment, the laser systems and methods described herein can be utilized to pattern a substrate to be utilized as a package frame for a semiconductor package having one or more interconnections formed therethrough and/or one or more semiconductor dies disposed therein. The laser systems described herein can produce tunable laser beams for forming features in a substrate or other package structure. Specifically, frequency, pulse width, pulse shape, and pulse energy of laser beams are tunable based on desired sizes of patterned features and on the material in which the patterned features are formed. The adjustability of the laser beams enables rapid and accurate formation of features in semiconductor substrates and packages with controlled depth and topography.