Semi-Permeable Film Covers for Precise Sensor Package Protection
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Solution Overview
Problem
Existing sensor packages face challenges in protecting sensors from exposure to dust, debris, pollution, and corrosive substances, especially during the PCB-mounting process, with manual or semi-manual application of protective films being inaccurate, time-consuming, and limited in capacity.
Innovation Solution
A method involving pre-singulation application of semi-permeable films to mold compounds covering semiconductor dies, followed by singulation to produce sensor packages, ensuring precise alignment and efficient protection of sensors with adhesive films that can be permanent or removable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual or semi-manual application of protective films is used, then flexibility in film application is maintained, but manufacturing precision and productivity deteriorate due to inaccuracy and time consumption
Solution Approach 1:
The protective film is applied to the mold compound before the semiconductor dies are packaged, allowing the film to be positioned and secured in advance. This preliminary application ensures precise alignment is maintained throughout subsequent packaging operations without requiring complex real-time adjustment mechanisms during the actual packaging process.
Solution Approach 2:
The mold compound serves as an intermediary carrier that holds both the protective film and the semiconductor dies. By applying the film to the mold compound rather than directly to individual dies or packages, the system achieves precise film positioning while simplifying the overall application process through a single unified substrate.
2Productivity
If protective films are applied after singulation, then individual package protection is achieved, but productivity and efficiency worsen due to increased handling and time requirements
Solution Approach 1:
The protective film is applied to the mold compound before singulation occurs, allowing multiple packages to be protected simultaneously in a single operation. This preliminary protection ensures that sensors are covered before any handling or processing that could expose them to contaminants, maintaining reliability while dramatically improving productivity by eliminating post-singulation film application steps.
3Strength
If adhesive is applied extensively to secure the film, then film attachment strength improves, but adhesive drying time and potential contamination risks increase
Solution Approach 1:
Adhesive is applied only in specific localized areas at the perimeter of the mold compound rather than across the entire surface. This localized application provides sufficient attachment strength to secure the film while minimizing the total volume of adhesive used, thereby reducing drying time and limiting the areas where contamination could occur during the drying process.
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 method achieves accurate, efficient, and cost-effective protection of sensor packages by ensuring precise film alignment and minimizing human intervention, reducing exposure risks and adhesive drying issues.
Implementation Method 1
a semi-permeable film abutting the adhesive and covering the cavity
Implementation Method 2
an adhesive abutting the top surface of the mold compound, and a semi-permeable film abutting the adhesive
Data Source
AI summary
In some examples, a sensor package includes a semiconductor die having a sensor; a mold compound covering a portion of the semiconductor die; and a cavity formed in a top surface of the mold compound, the sensor being in the cavity. The sensor package includes an adhesive abutting the top surface of the mold compound, and a semi-permeable film abutting the adhesive and covering the cavity. The semi-permeable film is approximately flush with at least four edges of the top surface of the mold compound.