Semiconductor Light Emitter Bonding and Dicing for Higher Yield
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Solution Overview
Problem
Existing methods for manufacturing semiconductor light emitting devices using surface-activated bonding face challenges such as complex device configuration, high costs, and reduced manufacturing yield due to issues like substrate cracking, internal stress, and uneven phosphor plate cutting.
Innovation Solution
A method involving polishing processes for both the light emitting element and the phosphor plate, followed by surface-activated bonding, incision forming, notch forming, and individualizing processes to improve bonding strength and manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface-activated bonding is performed in a vacuum device using ion beam irradiation, then bonding strength between phosphor plate and light emitting element is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the vacuum-based ion beam surface activation system with a mechanical/chemical surface treatment system performed in atmospheric conditions. Specifically, it uses abrasive paper or cloth for mechanical abrasion followed by chemical etching solutions to activate bonding surfaces, eliminating the need for complex vacuum devices while achieving sufficient bonding strength through alternative surface activation mechanisms.
Solution Approach 2:
The patent changes the operational parameters from vacuum environment with ion beam irradiation to atmospheric environment with mechanical abrasion and chemical etching. By adjusting surface treatment parameters such as abrasion pressure, etching solution concentration, and treatment duration, the patent achieves effective surface activation without requiring vacuum equipment, thus reducing device complexity while maintaining bonding quality.
2Measurement precision
If light emitting elements are individualized and arranged in advance before bonding, then alignment precision is improved, but manufacturing time and productivity decrease
Solution Approach 1:
The patent performs preliminary arrangement of light emitting elements on the phosphor plate before bonding, but does not require complete individualization and precise positioning of each element beforehand. Instead, elements are loosely arranged in their final positions, and the subsequent bonding process itself provides the precise alignment through surface contact and pressure application, eliminating time-consuming precision positioning steps while maintaining alignment accuracy.
Solution Approach 2:
The patent merges the arrangement, alignment, and bonding operations into a single integrated process. Light emitting elements are placed in their approximate final positions, and the bonding process simultaneously achieves both alignment (through surface contact) and permanent attachment (through pressure and activation), eliminating separate alignment and bonding steps that would otherwise be required.
3Manufacturing precision
If phosphor ceramics are cut into individual light emitting devices after bonding, then individualization precision is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent inverts the conventional sequence by bonding the phosphor plate to the light emitting elements first, and then cutting the assembled structure into individual devices. This reverse approach allows for simpler cutting operations on the already-bonded assembly, where the phosphor plate acts as a protective and guiding layer during cutting, improving precision while reducing the need for complex individual handling and positioning systems.
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
The proposed method enhances manufacturing yield by ensuring strong bonding between the phosphor plate and the light emitting element, reducing stress concentrations, and improving the accuracy of dividing the substrate and phosphor plate.
Implementation Method 1
a phosphor plate absorbing light emitted from a semiconductor light emitting layer and emitting fluorescence
Implementation Method 2
bonding surfaces of the light emitting elements and the phosphor ceramic are polished
Implementation Method 3
each bonding surface is irradiated with an ion beam of a rare gas element (at least one of He, Ne, Ar, and Kr)
Implementation Method 4
the bonding surfaces are brought into contact with each other and pressurized to bond these bonding surfaces
Data Source
AI summary
A stacked body is formed by polishing an upper surface of a light emitting element plate, polishing a lower surface of a phosphor plate, mounting the phosphor plate on a light emitting element, and applying heat and applying pressure. From the phosphor plate side, incisions are inserted into the stacked body at positions corresponding to gaps between a plurality of semiconductor light emitting layers. From the light emitting element side, notches are formed in the stacked body at the gaps between the plurality of semiconductor light emitting layers. A semiconductor light emitting device is individualized by dividing the stacked body between a tip of the incision and a tip of the notch. One of the incision and the notch is formed with a depth extending beyond a bonding surface between the phosphor plate and the light emitting element plate.