Water-Soluble Protective Coating for Clean Laser Dicing
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Solution Overview
Problem
Existing methods for laser dicing optical devices often result in contamination and incomplete removal of substrate areas due to the lack of a protective coating, which affects the quality of diced optical devices used in VR and AR applications.
Innovation Solution
A water-soluble protective coating comprising a polymer, solvent, and additive is selectively deposited over optical devices on a substrate using inkjet or screen printing, cured to remove the solvent, and then exposed to water after laser dicing to ensure clean separation of optical devices from the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If no protective coating is applied during laser dicing, then the process is simpler and faster, but contamination occurs and substrate areas are not completely removed
Solution Approach 1:
A protective coating is applied to the optical devices before the laser dicing process. This preliminary protective layer prevents contamination during dicing and ensures complete removal of substrate areas by providing a clear boundary between the device and substrate that the laser can effectively distinguish and separate.
2Manufacturing precision
If a protective coating is applied to prevent contamination, then device quality improves, but the coating must be removed afterward adding process steps
Solution Approach 1:
The protective coating is formulated with specific material properties that enable it to be selectively removed after dicing. The coating contains water-soluble components or components that react differently to laser heating compared to the optical device materials, allowing for easy removal through water rinsing or selective chemical etching without affecting the underlying device structures.
3Stability of the object's composition
If the protective coating material is not water-soluble, then coating stability is better, but environmental impact increases and removal becomes difficult
Solution Approach 1:
The protective coating utilizes polymers with transition properties - they exhibit sufficient stability during the laser dicing process to maintain their protective function, but contain water-soluble segments or cross-linking structures that allow easy removal afterward. Examples include polyvinylpyrrolidone (PVP), polyvinyl acetate (PVA), and polypropylene-containing materials that balance structural integrity during processing with ease of removal through water exposure.
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 reduces contamination and ensures complete removal of substrate areas, enhancing the quality and purity of diced optical devices while minimizing environmental impact through aqueous waste disposal.
Implementation Method 1
dicing the optical devices from the optical device substrate by projecting a laser beam to the areas between the optical devices
Implementation Method 2
The protective coating includes a polymer, a solvent, and an additive... exposing the protective coating to water to remove the protective coating from the optical devices that are diced
Data Source
AI summary
Methods of dicing optical devices from an optical device substrate are disclosed. The methods include disposing a protective coating only over the optical devices. The optical device substrate includes the optical devices disposed on the surface of the optical device substrate with areas therebetween. The areas of the optical device substrate are exposed by the protective coating. The protective coating includes a polymer, a solvent, and an additive. The methods further include curing the protective coating via a cure process so that the protective coating is water-soluble after the solvent is removed by the cure process, dicing the optical devices from the optical device substrate by projecting a laser beam to the areas between the optical devices, and exposing the protective coating to water to remove the protective coating from the optical devices that are diced.