LED Unit Trench Layout for Dense Packing Without Short Circuits
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Solution Overview
Problem
Conventional LED manufacturing methods face challenges in achieving a denser arrangement of light-emitting units on a substrate, leading to wasted semiconductor stack and reduced brightness due to improper trench formation and dicing line placement, which can result in short circuits between units.
Innovation Solution
The method involves forming a semiconductor stack with mesas and trenches to define light-emitting units, using a unique trench and dicing line arrangement where the first semiconductor layers between units are connected and reserved, allowing for a denser packing of light-emitting units without forming trenches as pre-defined dicing lines, and incorporating a current blocking layer and transparent conductive layer for efficient electrical connection and current spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If trenches are formed as pre-defined dicing lines to separate light-emitting units, then manufacturing precision is improved, but semiconductor stack is wasted and device density is reduced
Solution Approach 1:
The patent merges the functions of trenches (for electrical isolation) and dicing lines (for device separation) into a single integrated structure. The first semiconductor layer serves as both the isolation layer between light-emitting units and the material to be separated during dicing, eliminating redundant semiconductor stack removal and achieving both isolation and separation functions simultaneously.
Solution Approach 2:
The first semiconductor layer is given multiple functions: it acts as an isolation layer to prevent electrical short circuits between adjacent light-emitting units, serves as a structural element defining the device boundaries, and becomes the material separated along dicing lines. This multi-functionality reduces overall semiconductor waste while maintaining manufacturing precision.
2Productivity
If light-emitting units are arranged densely on the substrate, then device density and brightness are improved, but short circuits between units may occur
Solution Approach 1:
The first semiconductor layer acts as an intermediary isolation structure between adjacent light-emitting units. It provides electrical isolation to prevent short circuits while allowing the units to be arranged densely on the substrate. The trenches extending to this first semiconductor layer create effective electrical barriers without requiring excessive spacing between units.
Solution Approach 2:
Instead of relying solely on horizontal spacing between light-emitting units to prevent short circuits, the patent introduces vertical isolation through trenches that extend to the first semiconductor layer. This dimensional approach to isolation allows denser horizontal packing while maintaining reliable electrical separation between units.
3Ease of manufacture
If conventional dicing lines are used to separate devices, then manufacturing simplicity is maintained, but semiconductor waste increases and device density decreases
Solution Approach 1:
The patent combines the dicing line placement with the trench structure design. The dicing lines are positioned to align with the trench locations, allowing a single semiconductor layer (the first semiconductor layer) to serve as both the isolation structure and the separation plane. This merging maintains manufacturing simplicity while significantly reducing semiconductor waste compared to conventional approaches where trenches and dicing lines are separate features.
Data Source
AI summary
A method for manufacturing a light-emitting device, includes: forming a semiconductor stack on a substrate, wherein the semiconductor stack includes a first semiconductor layer, a second semiconductor layer and an active region formed therebetween; removing portions of the semiconductor stack to form a plurality of mesas and exposing a part of the first semiconductor layer, wherein the part of the first semiconductor layer includes a first portion and a second portion; forming a plurality of trenches by removing the first portion of the part of the first semiconductor to exposing a top surface of the substrate and a side wall of the first semiconductor, wherein the plurality of trenches defining a plurality of light-emitting units in the semiconductor stack; wherein in a top view, the plurality of trenches includes a first trench extending along a first direction and a second trench extending along a second direction not parallel with the first trench; and wherein the second trench includes an end; forming connection electrodes on the semiconductor stack to electrically connect the adjacent light-emitting units; and separating the substrate and the second portion of the part of the first semiconductor layer along a first dicing line not parallel with the second direction; wherein the first dicing line intersects the end of the second trench.