Single-Crystal Substrate Shield Tunnel Formation
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Solution Overview
Problem
Existing methods for dividing optical device wafers, such as those made of sapphire or gallium nitride substrates, are inefficient as they require multiple applications of a laser beam along the same division line to achieve the desired thickness, leading to poor productivity.
Innovation Solution
A method involving the application of a pulsed laser beam with a peak energy density between 1 TW/cm2 and 100 TW/cm2, positioned from the upper side of the substrate, to create fine holes and amorphous regions that form shield tunnels along division lines, allowing for efficient division of the wafer in a single pass regardless of thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulsed laser beam is applied multiple times to the same division line to divide the wafer, then the division is achieved, but the productivity deteriorates
Solution Approach 1:
The patent applies a specific peak energy density range (1-100 TW/cm²) to the pulsed laser beam, which enables the formation of shield tunnels in a single pass through the entire wafer thickness. This parameter optimization allows the laser to create fine holes and amorphous regions that effectively shield the propagation path, eliminating the need for multiple applications and thereby resolving the contradiction between reliable division and processing speed.
2Length of stationary object
If the wafer thickness is increased, then the device capacity is improved, but the number of laser applications required increases, deteriorating productivity
Solution Approach 1:
The patent positions the converged point of the pulsed laser beam at a predetermined location within the wafer thickness rather than at the surface, creating a three-dimensional processing approach. This enables the laser energy to be deposited at the optimal depth to form shield tunnels that extend through the entire thickness in a single application, allowing thicker wafers to be processed with the same number of laser applications and thus maintaining productivity while increasing device capacity.
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 increases productivity by enabling the formation of shield tunnels from the upper to the lower side of the substrate with a single laser application, improving the efficiency of wafer division and reducing debris scattering, thus enhancing device quality.
Implementation Method 1
setting a peak energy density of a pulsed laser beam to a value in a range from 1 TW/cm2 to 100 TW/cm2, and applying the pulsed laser beam to the single-crystal member while positioning a converged point of the pulsed laser beam at a predetermined position spaced from an upper side of the single-crystal member to grow fine holes and an amorphous region shielding the fine hole
Data Source
AI summary
A method of processing a single-crystal member includes setting the peak energy density of a pulsed laser beam to a value in a range from 1 TW/cm2 to 100 TW/cm2, and applying the pulsed laser beam to the single-crystal member while positioning a converged point of the pulsed laser beam at a predetermined position spaced from an upper side of the single-crystal member to grow a fine hole and a amorphous region shielding the fine hole from the upper side of the single-crystal member, thereby forming a shield tunnel in the single-crystal member.