Laser Gettering Sinks in Thin Semiconductor Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gettering techniques struggle to effectively trap heavy metals in thin semiconductor substrates, particularly due to the difficulty in forming sufficient gettering sites on substrates thinner than 50 μm and the generation of dislocations caused by internal stress during the formation of these sites.
Innovation Solution
A method involving multi-photon absorption using ultra-short pulsed-laser beams to form gettering sinks in specific micro-regions of the semiconductor substrate, which can be shaped to extend in the thickness direction and are designed to alleviate internal stress through controlled thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gettering techniques (IG or EG methods) are used to trap heavy metals, then heavy metal removal is achieved, but sufficient gettering capability cannot be obtained in thin substrates (≤50 μm) because most gettering sinks are removed by grinding
Solution Approach 1:
The invention transitions from forming gettering sinks primarily on the substrate surface (2D) to forming them throughout the substrate thickness (3D). By using laser beams to create gettering sinks that extend in the thickness direction, the solution充分利用 the third dimension to maintain gettering capability in thin substrates where surface-only approaches fail.
Solution Approach 2:
The invention replaces the mechanical grinding process with laser-based processing. Instead of using mechanical means to create and maintain gettering sinks, the patent employs laser beams to form gettering sinks that extend through the substrate thickness, eliminating the conflict between thinning and gettering capability.
2Productivity
If laser beams are condensed into a small area (≤1 mm) to form gettering sinks rapidly, then formation time is reduced, but internal stress and dislocation generation increase
Solution Approach 1:
The invention applies different laser processing conditions to different regions or stages of gettering sink formation. By controlling laser parameters such as pulse width, power, and scanning speed, the system creates optimal local conditions that balance rapid formation with minimal stress and dislocation generation.
Solution Approach 2:
The invention dynamically adjusts laser processing parameters (pulse width, power density, scanning speed) to optimize the balance between formation speed and quality. By changing these parameters during the process, the system achieves rapid gettering sink formation while controlling internal stress and dislocation generation.
3Length of stationary object
If the silicon substrate is thinned to ≤50 μm to enable device miniaturization, then device size is reduced, but heavy metal diffusion cannot be sufficiently suppressed after thinning
Solution Approach 1:
The invention performs gettering sink formation before or during the thinning process, rather than after. By creating gettering sinks that extend through the substrate thickness in advance, the system ensures heavy metal trapping capability is established before thinning removes surface gettering sinks, thus maintaining reliability in thin substrates.
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
This approach allows for the rapid and reliable formation of gettering sites with minimal dislocation defects, effectively trapping heavy metals and improving semiconductor device performance by suppressing internal stress and thermal shock.
Implementation Method 1
multi-photon absorption using ultra-short pulsed-laser beams to form gettering sinks
Implementation Method 2
condensing laser beams having a certain wavelength and a certain pulse width into a particular position in the thickness direction of the silicon substrate and reforming the characteristic of the single crystal silicon at the condensed position
Data Source
AI summary
A method for manufacturing a semiconductor substrate dedicated to a semiconductor device, in which multi-photon absorption is generated in a micro-region inside the semiconductor substrate by condensing laser beams in any micro-region inside the semiconductor substrate, and a gettering sink is formed by changing the crystal structure of only the micro-region.