Lid-to-Mold Package Sealing to Prevent Adhesive Bleeding
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Solution Overview
Problem
Packaged electronic devices experience glue flow-out or bleeding due to adhesive leakage, which affects the reliability and dimensions of the devices, particularly in radiofrequency applications where the dielectric constant of molding compounds introduces unwanted losses.
Innovation Solution
The inner portions of the lid rim and upper ring part abut each other without adhesive, forming a mechanical barrier, and the channel widens outwardly to prevent glue from entering the package cavity, ensuring that the adhesive flows outward instead of inward, thereby reducing flow resistance and preventing bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied between lid rim and upper ring part to connect them, then connection strength is improved, but glue flow-out or bleeding occurs affecting reliability and dimensions
Solution Approach 1:
The lid rim and upper ring part are divided into inner portions and outer portions. The inner portions abut each other without adhesive to form a mechanical barrier, while the outer portions are connected using adhesive. This segmentation prevents glue flow-out while maintaining connection strength.
Solution Approach 2:
The inner portions of the lid rim and upper ring part act as an intermediary mechanical barrier that prevents adhesive from flowing into the package cavity. This barrier structure allows the adhesive to be applied for connection while blocking its harmful flow.
2Ease of manufacture
If adhesive is applied to connect lid rim and upper ring part, then connection is achieved, but glue bleeding affects package dimensions
Solution Approach 1:
The connection structure is segmented into inner portions (for dimensional precision) and outer portions (for adhesive application). This allows easy manufacturing through adhesive bonding while preventing dimensional variation from glue bleeding.
Solution Approach 2:
Different regions of the lid rim and upper ring part have different functions: inner portions provide precise dimensional control through abutment, while outer portions provide connection through adhesive. This local differentiation solves both manufacturing ease and precision requirements.
3Strength
If adhesive is applied between lid rim and upper ring part, then bonding is achieved, but air pockets may form reducing reliability
Solution Approach 1:
The adhesive is extracted from the critical inner region where it would cause problems and confined to the outer portions only. This eliminates air pocket formation in the package cavity while maintaining bonding strength in the outer connection regions.
Solution Approach 2:
The inner portions serve as an intermediary barrier that prevents adhesive and air pockets from forming in the package cavity. This mechanical barrier allows bonding to occur in outer portions without compromising package reliability.
Data Source
AI summary
Example embodiments relate to packaged electronic devices. One example packaged electronic device includes a substrate. The packaged electronic device also includes a plurality of leads fixated relative to the substrate in a spaced apart manner. Additionally, the packaged electronic device includes a solidified molding compound that is fixedly connected to the plurality of leads. The solidified molding includes an upper ring part that extends away from the leads in a direction away from the substrate. Further, the packaged electronic device includes an electronic component mounted on the substrate and electrically connected to the leads. In addition, the packaged electronic device includes a lid having a lid base and a lid rim that extends towards the upper ring part. The lid rim is connected to the upper ring part using an adhesive. Each of the lid rim and upper ring part include an inner portion and an outer portion.