Transparent LDS Encapsulation for Accurate Die-to-Substrate Interconnects
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Solution Overview
Problem
The challenge in manufacturing semiconductor devices lies in the misalignment of structured formations during laser direct structuring (LDS) due to the opaque mold layer obscuring the die position, leading to potential electrical discontinuity and die damage, which complicates and expenses the equipment required for accurate processing.
Innovation Solution
Employing a light-permeable transparent molding compound filled with LDS additive particles, such as Chromium oxide, allows for visual inspection and accurate alignment of the laser beam, enabling proper die positioning and reducing the risk of misalignment and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an opaque molding compound is used for die encapsulation, then the die is protected from the outer environment, but the laser beam cannot be properly aligned with the die position due to lack of visibility
Solution Approach 1:
The patent applies a transparent or light-permeable molding compound instead of an opaque one, enabling the laser system to visually detect and align with the die position through the molding material. This transparency allows the laser beam to be directed accurately at the die pads while still maintaining die encapsulation and protection.
2Manufacturing precision
If fiducials are added to the leadframe for laser positioning, then alignment precision is improved, but device complexity and equipment cost increase
Solution Approach 1:
The patent removes the need for fiducials and complex positioning systems by utilizing the transparency of the molding compound. The laser system can directly observe and align with the die position through the transparent material, eliminating the requirement for additional fiducial markers and complex leadframe maps.
3Measurement precision
If an integrated X-Ray system is equipped on the laser source, then die position detection accuracy is improved, but machine complexity and cost increase significantly
Solution Approach 1:
The patent eliminates the need for expensive and complex integrated X-Ray systems by using a transparent molding compound that allows optical detection methods. Standard optical cameras or sensors can detect the die position through the transparent material, removing the requirement for heavy X-Ray equipment while maintaining adequate positioning accuracy.
4Manufacturing precision
If a transparent molding compound is used, then laser alignment is facilitated, but the molding compound must still provide adequate die encapsulation and environmental protection
Solution Approach 1:
The patent employs a transparent molding compound that combines the optical transparency needed for laser alignment with the protective and encapsulative properties required for die protection. This composite material approach ensures both visibility for manufacturing precision and adequate encapsulation for reliability.
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 facilitates precise alignment and processing of semiconductor devices, reducing the complexity and cost of equipment while ensuring accurate electrical connectivity and minimizing die damage, thereby improving the manufacturing efficiency and reliability of semiconductor devices.
Implementation Method 1
a light-permeable (transparent or clear) molding compound
Implementation Method 2
a laser beam can be used to transfer a desired structured pattern onto a plastic molding
Implementation Method 3
metallization (for instance via electroless plating with copper or other metals)
Data Source
AI summary
A semiconductor chip or die is mounted at a position on a support substrate. A light-permeable laser direct structuring (LDS) material is then molded onto the semiconductor chip positioned on the support substrate. The semiconductor chip is visible through the LDS material. Laser beam energy is directed to selected spatial locations of the LDS material to structure in the LDS material a pat gstern of structured formations corresponding to the locations of conductive lines and vias for making electrical connection to the semiconductor chip. The spatial locations of the LDS material to which laser beam energy is directed are selected as a function of the position the semiconductor chip which is visible through the LDS material, thus countering undesired effects of positioning offset of the chip on the substrate.