Tapered Die Sidewall Metallization for IR Shielding Coverage
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Solution Overview
Problem
Conventional semiconductor device assembly processes result in poor metal coating layer coverage on the sidewall surfaces of unpackaged semiconductor dies, leading to inadequate protection against electromagnetic radiation, particularly infrared (IR), which can affect the performance of light-sensitive semiconductor devices.
Innovation Solution
The implementation of a semiconductor device with tapered sidewalls and a metal coating layer that extends from the bottom side surface to the sidewall surfaces, where the sidewall metal layer defines a plane at an angle from 10° to 60° relative to the normal projected from the bottom plane, enabling uniform metal coating coverage and improved IR shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional flat sidewall structure is used, then the manufacturing process is simple, but the metal coating layer coverage on sidewall surfaces is poor
Solution Approach 1:
The patent applies asymmetry by changing the sidewall geometry from a conventional vertical flat surface to a tapered structure with specific angle ranges (10°-60°). This asymmetric shape allows the metal coating layer to be deposited uniformly across the sidewall surface, eliminating the poor coverage issue while maintaining manufacturing feasibility through standard semiconductor fabrication processes.
Solution Approach 2:
The patent utilizes parameter changes by specifying precise angular parameters for the tapered sidewall structure (10°-60° relative to the substrate plane). By optimizing this geometric parameter, the patent achieves uniform metal coating coverage on the sidewalls, directly resolving the coverage problem without requiring complex additional manufacturing steps.
2Ease of manufacture
If unpackaged semiconductor die are used to reduce size and cost, then manufacturing cost is reduced, but protection from electromagnetic radiation is insufficient
Solution Approach 1:
The patent applies composite materials by combining the semiconductor die with a metal coating layer deposited on the sidewalls and bottom surface. This composite structure maintains the cost advantages of unpackaged die while adding electromagnetic radiation shielding capability, as the metal layer blocks IR and other harmful radiation from reaching the sensitive circuitry.
Solution Approach 2:
The metal coating layer serves as an intermediary protective barrier between the semiconductor die and electromagnetic radiation. This intermediate layer absorbs or reflects IR radiation before it can penetrate into the die, thereby protecting the unpackaged device without requiring a full enclosure package.
3Object-affected harmful factors
If IR protection packages are added to shield semiconductor die, then electromagnetic radiation protection is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential IR protection function from the complex enclosure package and implements it through a simple metal coating layer applied directly to the die sidewalls and bottom. This extraction eliminates the need for additional protective housing while maintaining radiation shielding effectiveness, thereby reducing device complexity.
Solution Approach 2:
The patent uses a thin film metal coating layer as a flexible protective barrier that conformally coats the tapered sidewalls and bottom surface. This thin film approach provides effective EM radiation protection without the bulk and complexity of traditional rigid protective packages, maintaining device compactness.
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 solution effectively prevents the influence of electromagnetic radiation, including IR, from reaching the semiconductor die, enhancing the operational reliability of unpackaged semiconductor devices by ensuring uniform metal coating coverage on the sidewall surfaces, thus reducing the need for additional and costly IR protection packages.
Implementation Method 1
a layer of organic material, such as an epoxy, is applied to the sidewall surfaces and the bottom surfaces of an unpackaged semiconductor die, such as a WCSP, to try to block the transmission of IR from reaching the circuitry of the semiconductor die
Data Source
AI summary
A semiconductor device includes a semiconductor die having a top side surface comprising a semiconductor material including circuitry therein having bond pads connected to nodes in the circuitry, a bottom side surface, and sidewall surfaces between the top side surface and the bottom side surface. A metal coating layer including a bottom side metal layer is over the bottom side surface that extends continuously to a sidewall metal layer on the sidewall surfaces. The sidewall metal layer defines a sidewall plane that is at an angle from 10° to 60° relative to a normal projected from a bottom plane defined by the bottom side metal layer.