Wafer-Level Marking Using Photosensitive Layers for Semiconductor Packages
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Solution Overview
Problem
Conventional methods for marking semiconductor packages, such as laser marking and ink printing, are slow, capital-intensive, and prone to defects, with limitations in character size and resolution, making them inefficient for high-volume manufacturing and resulting in increased costs and manufacturing cycle times.
Innovation Solution
A method involving the formation of identifying marks within a photosensitive layer on the semiconductor wafer, using a digital exposure machine and developer, allows for high-resolution, machine-readable marks with feature sizes less than 150 micrometers, enabling efficient and consistent marking across multiple semiconductor devices without increasing processing time or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser marking or ink printing methods are used to mark semiconductor packages, then identifying marks can be formed on the package surface, but the marking process is slow, capital-intensive, and results in low throughput with limited resolution
Solution Approach 1:
The identifying marks are formed on the semiconductor wafer before singulation into individual devices. By performing the marking operation at the wafer level rather than on finished packages, the process achieves high throughput while maintaining resolution, as the marking is done once per wafer containing multiple devices
Solution Approach 2:
The patent replaces conventional laser marking or ink printing mechanisms with a photolithographic approach using photosensitive materials. This substitution enables high-resolution marking through optical patterning processes that are inherently more precise and scalable than mechanical or thermal marking methods
2Reliability
If conventional laser marking or ink printing methods are used to mark semiconductor packages, then identifying marks can be formed on the package surface, but the process increases manufacturing cycle time and costs
Solution Approach 1:
By performing marking operations during wafer fabrication before final packaging, the process eliminates subsequent marking steps that would extend the manufacturing cycle. The marks are formed as part of the standard wafer processing sequence, ensuring consistency without adding cycle time
Solution Approach 2:
The photolithographic marking process utilizes the same equipment and materials already employed in standard semiconductor manufacturing for pattern formation. This multi-functional approach allows marking to be performed using existing infrastructure, reducing both time and cost
3Manufacturing precision
If conventional laser marking or ink printing methods are used to mark semiconductor packages, then identifying marks can be formed on the package surface, but the process is prone to defects and has limited character size
Solution Approach 1:
The patent replaces laser or ink-based marking with photolithographic patterning using photosensitive materials. This enables precise control of feature sizes down to sub-micrometer dimensions through optical resolution limits, while the standardized process reduces variability and defects compared to conventional methods
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 approach enhances throughput, reduces manufacturing cycle time, and improves marking resolution, enabling the production of semiconductor packages with unique identifying information at a higher rate than traditional methods, while minimizing defects and costs.
Implementation Method 1
A photosensitive layer can be formed over the wafer and on a backside of each of the plurality of semiconductor die within the wafer with a coating machine. An identifying mark can be formed within the photosensitive layer for each of the plurality of semiconductor die with a digital exposure machine and a developer
Data Source
AI summary
A method of making a semiconductor device can include providing a wafer comprising a plurality of semiconductor die, wherein each semiconductor die comprises an active surface and a backside opposite the active surface. A photosensitive layer can be formed over the wafer and on a backside of each of the plurality of semiconductor die within the wafer with a coating machine. An identifying mark can be formed within the photosensitive layer for each of the plurality of semiconductor die with a digital exposure machine and a developer, wherein a thickness of the identifying mark is less than or equal to 50 percent of a thickness of the photosensitive layer. The photosensitive layer can be cured. The wafer can be singulated into a plurality of semiconductor devices.