Dual-Path Laser Processing for Low-k Film Removal and Groove Formation
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Solution Overview
Problem
The peeling of Low-k film at the interface with the silicon substrate during laser processing of wafers, which degrades device quality, and the need for separate laser processing apparatuses with different wavelengths to form grooves and remove the film, leading to inefficiency.
Innovation Solution
A laser processing apparatus with a pulsed laser beam system that includes a wavelength converter to suppress leaked light, form grooves, and remove the Low-k film using a single apparatus by adjusting the wavelength and repetition frequency of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laser beam is applied to form grooves on both sides of the dicing line, then the insulation film peeling is prevented, but the leaked light causes peeling at the interface between the Low-k film and silicon substrate
Solution Approach 1:
A beam splitter is introduced as an intermediary component to divide the laser beam into multiple paths. This allows the laser energy to be distributed to form grooves on both sides of the dicing line while controlling the beam distribution to prevent leaked light from causing interface peeling. The beam splitter mediates between the need for effective groove formation and the need to prevent harmful light leakage effects.
2Reliability
If two lines of grooves are formed to prevent film peeling, then the insulation film is protected, but the Low-k film remains between the grooves causing unstable cutting
Solution Approach 1:
The laser processing is segmented into two distinct stages: first forming grooves on both sides of the dicing line to protect the insulation film, then removing the Low-k film material remaining between the grooves. This segmentation allows each operation to be optimized independently - groove formation for protection and material removal for cutting stability - thereby resolving the contradiction between film protection and cutting precision.
3Manufacturing precision
If the Low-k film is completely removed between grooves using laser, then cutting stability is improved, but a second laser apparatus with different wavelength is needed
Solution Approach 1:
A single laser apparatus is designed to perform multiple functions: forming grooves on both sides of the dicing line and removing the Low-k film material between the grooves. By optimizing the laser parameters and using appropriate beam shaping components, one laser system achieves what previously required two separate apparatuses, thereby reducing device complexity while maintaining cutting stability.
4Productivity
If different wavelengths are used for groove formation and film removal, then processing effectiveness is improved, but two laser processing apparatuses are required
Solution Approach 1:
The patent merges the functions of two separate laser processing apparatuses into one unified system. By combining the groove formation capability and the Low-k film removal capability into a single laser apparatus with appropriate optical components and parameter control, the system achieves effective processing for both operations without requiring multiple separate devices, thus improving productivity while reducing device complexity.
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
Prevents peeling at the Low-k film interface and efficiently forms grooves and removes the film using a single apparatus, eliminating the need for multiple laser systems.
Implementation Method 1
a wavelength converter that is disposed on the second optical path, and converts a wavelength of the pulsed laser beam oscillated by the oscillator
Implementation Method 2
a first condenser that is disposed on the first optical path, and condenses the pulsed laser beam onto the wafer held on the holding means
Data Source
AI summary
The processing apparatus includes a holding means that holds a wafer; a laser beam applying unit that applies a pulsed laser beam onto the wafer held on the holding means; and process-feeding means that process-feeds the holding means and the laser beam applying unit relative to each other. The laser beam applying unit includes an oscillator that oscillates a pulsed laser beam; a splitting portion that splits the pulsed laser beam, oscillated by the oscillator, into a first optical path and a second optical path; a first condenser that is disposed on the first optical path and condenses the pulsed laser beam onto the wafer; a wavelength converter that is disposed on the second optical path and converts a wavelength of the pulsed laser beam oscillated by the oscillator; and a second condenser that condenses a pulsed laser beam, generated after the wavelength is converted, onto the wafer.