Laser Melting Adhesive Layer for Defective Semiconductor Device Removal
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Solution Overview
Problem
The manufacturing process of stacked device chips is hindered by defective semiconductor devices and junction failures, leading to a reduction in yield due to the inclusion of defective devices and junction failures in the wafer assembly.
Innovation Solution
A method involving a wafer preparing step, determining defective devices, applying a laser beam to melt the adhesive layer of defective devices, treating the devices by releasing them from the substrate, and rejoining non-defective devices to maintain the assembly's integrity, thereby ensuring only non-defective devices are used in the final product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If defective semiconductor devices are included in the wafer assembly, then the manufacturing process can proceed without additional inspection steps, but the yield of stacked devices is reduced due to defective devices
Solution Approach 1:
The patent applies preliminary action by performing laser processing on the adhesive layer of defective semiconductor devices before the wafer stacking process. This advance treatment removes defective devices from the wafer assembly in advance, preventing them from reducing the yield of stacked devices while maintaining manufacturing efficiency
Solution Approach 2:
The patent uses the adhesive layer as an intermediary element that can be selectively removed via laser processing. This intermediary approach allows for the removal of defective devices without damaging other components, resolving the contradiction between maintaining productivity and ensuring reliability
2Device complexity
If junction failures are not detected before stacking, then the inspection process is simplified, but stacked devices with junction failures are produced, reducing yield
Solution Approach 1:
The patent performs preliminary laser processing on the adhesive layer of devices with junction failures before stacking. This advance action eliminates defective devices without requiring complex post-stack inspection, maintaining simple inspection processes while ensuring high yield
Solution Approach 2:
The patent extracts defective devices with junction failures from the wafer assembly by selectively removing their adhesive layers through laser processing. This extraction method eliminates harmful elements while preserving the integrity of the remaining functional devices
3Reliability
If all semiconductor devices are thoroughly inspected for defects, then the yield of stacked devices is maximized, but the manufacturing time and cost increase
Solution Approach 1:
The patent performs preliminary laser processing on only those devices identified as defective through basic inspection, rather than thoroughly inspecting all devices. This selective preliminary action achieves high yield while minimizing manufacturing time by avoiding unnecessary inspection and processing of functional devices
Solution Approach 2:
The patent applies partial action by performing laser processing only on defective devices rather than all devices in the wafer assembly. This selective approach ensures high yield by removing only problematic devices while avoiding the time loss associated with processing all devices
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 method effectively prevents the inclusion of defective devices in the final product, enhancing the yield of semiconductor devices by ensuring only functional devices are stacked, thus increasing productivity.
Implementation Method 1
applying a laser beam to heat one of the adhesive layers by which one of the semiconductor devices that has been determined as defective is bonded to the substrate, thereby melting the adhesive layer
Implementation Method 2
melting the adhesive layer in an area of the wafer that is irradiated with the laser beam
Data Source
AI summary
A method of manufacturing a wafer includes a wafer preparing step of preparing a wafer including a plurality of semiconductor devices joined to a substrate by respective adhesive layers, a determining step of determining whether each of the semiconductor devices joined to the substrate is defective or non-defective, a laser beam applying step of applying a laser beam to heat one of the adhesive layers by which one of the semiconductor devices that has been determined as defective is bonded to the substrate, thereby melting the adhesive layer in an area of the wafer that is irradiated with the laser beam, and a treating step of treating the semiconductor device released from a bonded state due to the adhesive layer being melted in the laser beam applying step.