Wafer Dicing Beam Matrix for Deep Grooves Without Re-Melting Voids
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Solution Overview
Problem
Conventional laser processing methods face challenges in efficiently cutting wafers without causing re-melting voids or compromising the integrity of the semiconductor devices due to variations in beam size and distribution, leading to reduced productivity and potential damage.
Innovation Solution
A laser processing device that splits laser beams into multiple patterns with varying sizes and arrangements, using a beam matrix to form grooves with controlled beam fluence, preventing re-melting voids and ensuring deep depth while maintaining groove width, thereby enhancing cutting precision and reducing damage to the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single laser beam is used for cutting, then the device structure is simple, but the cutting precision and groove quality are insufficient due to re-melting voids
Solution Approach 1:
The single laser beam is segmented into multiple laser beams (e.g., 2x2, 3x3, or 4x4 arrays) by using a beam shaping element with diffractive optical structures. This segmentation allows simultaneous irradiation of multiple points on the wafer, improving cutting precision and groove quality by preventing re-melting voids while maintaining controlled beam fluence distribution.
Solution Approach 2:
The invention transitions from a single-beam approach to a multi-beam array approach by introducing spatial distribution in both horizontal and vertical dimensions. The beam matrix arrangement (e.g., 2x2, 3x3, 4x4) creates a two-dimensional pattern of laser beams, enabling precise control over the groove formation process and eliminating re-melting defects through optimized fluence distribution.
2Manufacturing precision
If multiple laser beams are used to improve cutting quality, then the groove depth and precision improve, but the beam fluence control becomes more complex
Solution Approach 1:
The invention controls beam fluence parameters by designing specific diffractive optical structures on the beam shaping element. These structures are configured to distribute laser energy across multiple beams with controlled intensity profiles, ensuring optimal fluence for deep groove formation without re-melting. The parameters include beam spacing, relative intensities, and phase relationships, all optimized through the optical design.
Solution Approach 2:
A beam shaping element acts as an intermediary between the laser source and the wafer. This element contains diffractive optical structures that automatically perform the complex task of splitting, positioning, and intensity-adjusting multiple beams. The intermediary simplifies the overall system by integrating fluence control functionality into a single optical component rather than requiring complex external control systems.
3Productivity
If high laser power is used to achieve deep grooves, then the cutting speed improves, but re-melting voids form reducing groove quality
Solution Approach 1:
The total laser power is segmented across multiple beams, allowing the use of high total power while distributing the energy density. This segmentation prevents localized overheating and re-melting voids that occur with single high-power beams, while still achieving deep grooves through the cumulative effect of multiple beams irradiating the same area simultaneously.
Solution Approach 2:
The beam shaping element creates local quality variations in the fluence distribution across the groove area. By optimizing the intensity profile of each individual beam and their spatial arrangement, the system achieves uniform energy distribution that prevents re-melting while maintaining high cutting speed. The local fluence at each beam position is carefully controlled to match the material's absorption characteristics.
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
The device achieves precise cutting with deep grooves, minimizing re-melting voids and protecting the integrity of semiconductor devices, thus improving productivity and reducing defects in the wafer dicing process.
Implementation Method 1
a beam shaper configured to split the laser beam generated by the beam generator into a plurality of laser beams through diffraction and to form at least one beam pattern of the plurality of laser beams via a beam matrix
Implementation Method 2
a metal or insulating layer included in the workpiece may be removed by using the thermal energy of the laser beam
Implementation Method 3
a cutting process that cuts the workpiece into multiple units through heat melting
Data Source
AI summary
A laser processing device includes a beam generator configured to generate a laser beam, and a beam shaper configured to split the laser beam generated from the beam generator into a plurality of laser beams through diffraction and form a pattern of the laser beam based on a beam matrix, wherein the beam matrix includes beam patterns having a plurality of beam sizes.