Semi-Permeable Film Covering for Sensor Package Singulation
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Solution Overview
Problem
Existing sensor packages face challenges in protecting sensors from dust, debris, pollution, and corrosive substances, especially during the PCB-mounting process, due to inefficient and time-consuming manual or semi-manual application of protective films, which becomes increasingly difficult as sensor sizes decrease.
Innovation Solution
A method involving covering an array of semiconductor dies with a mold compound and coupling a semi-permeable film to the top surface using an adhesive, allowing for accurate and efficient application of the film across multiple sensor packages before singulation, ensuring precise alignment and protection from harmful substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual or semi-manual application of protective films is used, then protection from environmental exposure is achieved, but the process becomes inefficient and time-consuming
Solution Approach 1:
The protective film is applied to the mold compound before the semiconductor dies are mounted and before singulation occurs. This preliminary application allows the film to cover multiple sensor packages simultaneously, dramatically improving productivity while maintaining reliable protection. The film is positioned and secured in advance, so that when the package is singulated, each individual sensor package already has its protective film in place.
2Reliability
If protective films are applied after singulation, then individual package protection is achieved, but the process becomes increasingly difficult as sensor sizes decrease
Solution Approach 1:
The protective film is applied to the entire array of sensor packages while they are still connected in the mold compound, before singulation. This approach allows for much higher manufacturing precision because the film application process works with larger, more manageable dimensions. The film can be accurately positioned and secured across the entire array, and then each individual package is separated with the film already in place, eliminating the need for difficult post-singulation film application on tiny sensors.
3Reliability
If protective films are applied to each individual package, then precise protection is achieved, but the process becomes time-consuming and costly
Solution Approach 1:
The protective film application process is merged with the mold compound processing. Instead of applying films to individual sensor packages separately, the film is applied to the entire array of packages while they are still connected in the mold compound. This allows multiple packages to be protected simultaneously in a single operation, dramatically reducing processing time and cost while maintaining effective protection for each individual package.
4Object-affected harmful factors
If semi-permeable film is used, then protection from harmful substances is achieved, but the film must be precisely aligned with sensor cavities
Solution Approach 1:
The semi-permeable film is applied and aligned with the sensor cavities while the packages are still in the mold compound array, before singulation. The mold compound structure provides natural alignment references, and the film can be positioned to cover the entire array of sensor cavities simultaneously. This preliminary alignment is much more achievable than post-singulation alignment, as the larger mold compound structure provides better mechanical stability and alignment references.
Solution Approach 2:
The semi-permeable film is designed to cover the entire top surface of the mold compound, including all sensor cavities within that surface. This approach ensures that each sensor cavity receives appropriate protection through the semi-permeable film, which allows selective permeation of gases and vapors while blocking dust and larger particles. The film's properties are optimized for the specific protection needs of the sensors.
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 accuracy, reduces costs, and enables rapid processing of large groups of sensor packages with minimal human intervention, while maintaining effective protection from environmental exposures during the sensor package's life cycle.
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.