Laser Mold Removal for IC Packages
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Solution Overview
Problem
Conventional methods for removing the resin mold from IC packages are inefficient, leading to slow processing speeds, potential damage to the semiconductor chip, and issues with waste liquid treatment and corrosion, as well as incomplete removal of the resin.
Innovation Solution
A mold removing method using a laser processing technique that measures the thickness of the mold by emitting a measurement laser beam, normalizing the reflected light quantity, and adjusting the laser emission conditions to precisely remove the mold without chemical solutions, ensuring high-speed unsealing and minimizing damage to the IC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical solution method is used to remove resin mold, then the mold can be removed, but waste liquid treatment and corrosion of apparatus occur
Solution Approach 1:
The patent replaces the chemical solution method with a laser-based measurement and removal system. The laser beam measures mold thickness by detecting reflected light intensity, and the same or a different laser removes the mold through ablation, eliminating chemical waste and corrosion issues entirely.
Solution Approach 2:
The patent changes the physical state and parameters of the mold material through controlled laser heating. By adjusting laser power, pulse duration, and scanning speed, the mold material undergoes phase changes from solid to vapor, enabling precise removal without chemical reactions.
2Object-generated harmful factors
If dry etching is used to remove resin mold, then no waste liquid is generated, but processing speed is low
Solution Approach 1:
The patent utilizes rapid phase transition of the resin mold material from solid to gas through laser ablation. This direct sublimation process occurs almost instantaneously, achieving high processing speeds while maintaining a clean environment without liquid waste generation.
Solution Approach 2:
The patent employs pulsed laser operation with optimized pulse duration and frequency. The periodic laser pulses allow controlled material removal at high speed, with each pulse removing a precise amount of material through ablation, achieving both high productivity and clean processing.
3Device complexity
If conventional removal methods are used without recognizing chip position, then the process is simple, but the semiconductor chip may be damaged or resin cannot be completely removed
Solution Approach 1:
The system uses the mold material itself as the measurement target. The laser beam measures the thickness of the mold by detecting the reflected light from the mold-chip interface, automatically identifying the chip position and mold boundaries without requiring external sensors or complex positioning systems.
Solution Approach 2:
The patent implements real-time feedback control where the reflected light intensity from the laser measurement is continuously monitored. This feedback provides information about mold thickness and chip position, allowing the system to adjust laser parameters dynamically to prevent chip damage and ensure complete mold removal.
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
Enables high-speed unsealing of IC packages without chemical solutions, accurately monitoring and removing the mold to the minimum thickness, thereby preventing damage to the semiconductor chip and addressing the limitations of conventional methods.
Implementation Method 1
irradiating the molded member with the measurement laser beam to measure an emitted light quantity toward the molded member and a reflected light quantity from the molded member
Implementation Method 2
removing the molded member by laser processing
Data Source
AI summary
A laser mold removing method of the invention is for processing a composite material composed of a plurality of materials having different reflectances to a laser beam, and includes emitting laser beam in which a processing laser beam for processing the processing object and a measurement laser beam adapted to irradiate the processing object and having an output smaller than that of the processing laser beam are emitted, measuring a reflected light quantity of the measurement laser beam reflected by the processing object, and controlling based on the reflected light quantity.