Laser Processing Apparatus with Thinning-Out Unit for Chip Division
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Solution Overview
Problem
Conventional laser processing technologies face limitations in adjusting processing elements such as feed speed, laser beam output power, repetition frequency, pulse width, and spot diameter, which restrict further improvements in processing quality.
Innovation Solution
A laser processing apparatus with a chuck table, a laser oscillator that oscillates pulsed laser beams with a pulse width shorter than electronic excitation time, a condenser, thinning-out means to manage pulsed laser beams, and an amplifier to increase output power, ensuring that subsequent laser beams are applied during electronic excitation and after heat release, thereby improving processing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse width is extended to increase energy deposition, then processing efficiency is improved, but heat accumulation and thermal damage occur
Solution Approach 1:
The patent employs periodic pulsed laser irradiation with carefully controlled pulse width and repetition frequency. By using pulses shorter than the electronic excitation time and controlling the repetition frequency, the system achieves cumulative processing effect while allowing heat dissipation between pulses, thus avoiding thermal damage while maintaining high processing efficiency
Solution Approach 2:
The patent applies preliminary low-energy pulses to activate electronic excitation before applying subsequent higher-energy pulses. This preliminary action prepares the material by exciting electrons, making them more responsive to subsequent pulses and reducing the total energy needed, thereby preventing heat accumulation while maintaining processing efficiency
2Productivity
If the repetition frequency is increased to reduce processing time, then productivity is improved, but heat release time is insufficient causing thermal damage
Solution Approach 1:
The patent optimizes the repetition frequency parameter to be within a specific range that allows sufficient heat release time between pulses. By carefully selecting this parameter along with pulse width and energy, the system achieves high processing speed without causing thermal damage, resolving the contradiction between productivity and thermal safety
3Manufacturing precision
If laser beam energy is increased to improve processing depth, then processing quality is improved, but electronic excitation interference occurs
Solution Approach 1:
The patent uses preliminary low-energy pulses to activate electronic excitation in the material before applying higher-energy pulses for deep processing. This preliminary activation reduces the threshold for subsequent energy deposition, allowing deep processing with lower total energy input, thereby avoiding electronic excitation interference while achieving desired processing depth
Solution Approach 2:
The patent maintains continuous electronic excitation through carefully timed repeated pulses, keeping electrons in an activated state throughout the processing sequence. This continuity allows each pulse to build upon the previous excitation, achieving deep processing without needing to repeatedly overcome the electronic excitation threshold, thus avoiding interference while maintaining processing depth
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 apparatus enhances laser processing quality by promoting processing during electronic excitation and inhibiting heat effects, leading to improved division and modification of device chips with enhanced precision and efficiency.
Implementation Method 1
a laser oscillator in which a repetition frequency is set so as to oscillate a pulsed laser having a pulse width shorter than a time of electronic excitation caused by irradiating the workpiece with a pulsed laser beam
Implementation Method 2
a pulse width shorter than a time of electronic excitation caused by irradiating the workpiece with a pulsed laser beam
Implementation Method 3
a condenser that irradiates the workpiece held on the chuck table with the pulsed laser beams oscillated by the laser oscillator
Implementation Method 4
an amplifier that is disposed between the thinning-out means and the condenser and increases output power of the pulsed laser beams necessary for processing
Implementation Method 5
thinning-out means for guiding the pulsed laser beams necessary for processing to the condenser by thinning out and discarding pulsed laser beams in a predetermined cycle
Data Source
AI summary
A laser beam irradiation unit of a laser processing apparatus includes: a laser oscillator in which a repetition frequency is set so as to oscillate a pulsed laser having a pulse width shorter than a time of electronic excitation caused by irradiating the workpiece with a laser beam and oscillate at least two pulsed lasers within the electronic excitation time; a condenser that irradiates the workpiece held on the chuck table with the pulsed laser beams oscillated by the laser oscillator; and a thinning-out unit that is disposed between the laser oscillator and the condenser and guides the pulsed laser beams necessary for processing to the condenser by thinning out and discarding pulsed laser beams in a predetermined cycle.