Semiconductor Package Cavity Sidewalls to Block Mold Encroachment
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Solution Overview
Problem
Existing semiconductor packages face challenges in maintaining consistent cavity dimensions and preventing mold material encroachment, which can impede the operation of components like sensors and LEDs, due to variations in metal wall structures and the settling of mold materials during assembly.
Innovation Solution
A semiconductor package design featuring a polymer structure with an uneven inner sidewall profile, formed using a laminate process with multiple layers of polyimide, which reduces height variations and captures mold material, ensuring consistent component interaction and reducing the risk of mold material settling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal wall structure is used to form the cavity, then the cavity can be formed to enclose the interface region, but the height of the metal wall structure varies, causing mold material to encroach into the cavity
Solution Approach 1:
The patent changes the material parameter from metal to polymer and modifies the geometric parameter by creating an uneven inner sidewall profile with alternating aperture sizes. This combination of material and geometric parameter changes achieves both consistent cavity dimensions and prevention of mold material encroachment, resolving the technical contradiction between manufacturing precision and reliability.
2Strength
If mold material is used during assembly, then the semiconductor die is encapsulated for protection, but the mold material settles and encroaches into the cavity impeding component operation
Solution Approach 1:
The patent applies preliminary anti-action by designing the uneven inner sidewall profile before the molding process. The alternating aperture sizes create a geometric constraint that prevents mold material from settling and encroaching into the cavity, countering the harmful effect of mold material settling before it can occur during assembly.
Solution Approach 2:
The patent converts the potential harm of mold material flow into a benefit by using the uneven sidewall profile to capture and contain the mold material in designated areas (larger apertures), preventing it from reaching the interface region while still allowing the encapsulation to provide protective strength.
3Ease of manufacture
If a uniform polymer structure is used, then the manufacturing process is simplified, but the cavity dimensions vary and do not maintain consistency
Solution Approach 1:
The patent applies segmentation by dividing the polymer structure into multiple layers with different aperture sizes that alternate along the height. This segmentation maintains relative manufacturing simplicity while achieving consistent cavity dimensions through the cumulative effect of multiple standardized layers, resolving the contradiction between ease of manufacture and manufacturing precision.
Data Source
AI summary
Semiconductor packages with cavities and methods of making such semiconductor packages are described. The semiconductor package includes a semiconductor die including an interface region where various components configured to interact with an environment surrounding the package can be located. Such components include a humidity sensor, a temperature sensor, a light emitting diode, a solid-state laser, a photodiode, or the like. The semiconductor package includes an opening above the interface region to facilitate proper and adequate operations of the components. The semiconductor package also includes a polymer structure surrounding the interface region, thereby forming the opening. The polymer structure has an uneven inner sidewall profile formed by multiple layers of a polymer material.