Flip-Chip LED Electrode Layout to Prevent Leakage Paths
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Solution Overview
Problem
Conventional LED chips with ODR structures are prone to electric leakage due to the potential connection of P-type and N-type electrodes caused by insulation layer breaks or cracks, reducing reliability.
Innovation Solution
The LED chip design incorporates double-layer homogeneous electrodes with third N-type and P-type electrodes that do not overlap spatially, ensuring no contact between electrodes of different polarities, even in the event of insulation layer failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the metal layer of the P-type electrode extends to the bottom of the N-type pad with SiO2 insulation layer isolation, then the electrode structure is simplified, but the reliability deteriorates due to potential insulation layer breakage causing electric leakage
Solution Approach 1:
The patent divides the electrode structure into multiple independent layers: first electrode layer (P-type or N-type), second electrode layer (opposite polarity), and third electrode layer (same polarity as first). This segmentation ensures that even if one insulation layer fails, the homogeneous third layer prevents direct contact between opposite polarity electrodes, resolving the reliability issue while maintaining structural organization.
Solution Approach 2:
The patent introduces a vertical stacking dimension with three distinct electrode layers separated by insulation layers. This multi-dimensional arrangement transforms the conventional planar electrode design into a layered structure where the third electrode layer provides an additional protective dimension, preventing lateral electric leakage paths while maintaining electrical connectivity through vertical through-holes.
2Ease of manufacture
If the insulation layer is used to isolate P-type and N-type electrodes, then the manufacturing process is simplified, but the reliability worsens due to insulation layer cracks causing electrode connection
Solution Approach 1:
The patent applies beforehand cushioning by introducing a third electrode layer with the same polarity as the first layer, positioned between the first and second electrode layers. This pre-established protective layer acts as a cushion against potential insulation failure, ensuring that even if the first or second insulation layers crack, the homogeneous third electrode layer prevents direct contact between opposite polarity electrodes, thereby cushioning against reliability failures.
3Reliability
If double-layer homogeneous electrodes are adopted, then the reliability is improved by preventing electrode contact, but the device complexity increases
Solution Approach 1:
The patent applies homogeneity by making the third electrode layer have the same material composition and electrical properties as the first electrode layer. This homogeneous design simplifies the manufacturing process (using identical deposition techniques and materials) while providing enhanced reliability, as the third layer acts as a protective barrier with predictable electrical behavior, reducing the complexity of designing and analyzing heterogeneous multi-material structures.
Data Source
AI summary
The present disclosure relates to the technical field of semiconductor manufacturing, and in particular to an LED chip and a preparation method thereof, including: a substrate, an epitaxial layer, a current blocking layer, a current spreading layer, a first P-type electrode, a first N-type electrode, a first insulation layer, a second P-type electrode, a second N-type electrode, a second insulation layer, a third P-type electrode, a third N-type electrode, a P-type pad and a N-type pad. As for the LED chip, the electrode design of the flip chip is improved and a third N-type electrode and a third P-type electrode are added. The third N-type electrode and the P-type pad have no overlap spatially, similarly, the third P-type electrode and the N-type pad have no overlap spatially.