Molded Air-Cavity Package Pillar Support for RF Sealing
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Solution Overview
Problem
Molded air-cavity packages for RF applications often suffer from warpage in the lower part, leading to unpredictable placement of the cover, which can result in air leakage and inconsistent adhesive distribution, causing field rejects and reduced package reliability.
Innovation Solution
The use of spaced apart pillars formed by separate first and second cover supporting elements, arranged in the inner region and cover base, instead of continuous hard-stop features, to define the cover's position relative to the body, ensuring a predictable alignment and reliable sealing by using intermediate adhesive, and a channel that widens to prevent adhesive flow into the cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If continuous hard-stop features are used around the entire perimeter to define package height and control adhesive volume, then adhesive control is improved, but warpage-induced unpredictable cover placement occurs leading to air leakage and adhesive flow inconsistencies
Solution Approach 1:
The continuous hard-stop feature is divided into multiple separate pillars distributed around the perimeter. This segmentation allows each pillar to independently support the cover at critical points while accommodating warpage, preventing the air leakage issues that occur with continuous hard-stops on warped surfaces.
Solution Approach 2:
Instead of a uniform continuous hard-stop, the invention uses localized pillars at specific positions where support is most needed. The pillars are strategically placed to provide local support points that accommodate warpage while maintaining adhesive control at critical sealing locations.
2Loss of substance
If hard-stop features extend around the entire perimeter to prevent adhesive flow, then adhesive containment is improved, but cover placement becomes unpredictable due to warpage resulting in field rejects
Solution Approach 1:
The continuous adhesive barrier is segmented into discrete pillars, which provide sufficient adhesive containment while allowing the cover to settle predictably on the pillar tops, eliminating the placement precision issues caused by continuous hard-stops on warped substrates.
Solution Approach 2:
The pillars act as intermediary support elements between the warped lower part and the cover. They provide a stable reference surface for cover placement while still containing adhesive through their strategic positioning and geometry.
3Quantity of substance
If continuous hard-stop features are used to define channel volume, then adhesive amount control is improved, but large gaps appear between cover and lower part due to unpredictable tilted position
Solution Approach 1:
The continuous channel-defining hard-stop is segmented into discrete pillars, which maintain adhesive volume control through their distributed positioning while preventing large gaps by providing multiple localized support points that accommodate warpage-induced tilting.
Solution Approach 2:
Rather than attempting to maintain a uniform channel volume with continuous hard-stops on warped surfaces, the invention uses locally positioned pillars to define adhesive regions at critical points, accepting variable channel geometry while ensuring adequate adhesive distribution.
Data Source
AI summary
The present invention relates to a molded air-cavity package. In addition, the present invention is related to a device comprising the same. The present invention is particularly related to molded air-cavity packages for radio-frequency ‘RF’ applications including but not limited to RF power amplifiers.Instead of using hard-stop features that are arranged around the entire perimeter of the package in a continuous manner, the present invention proposes to use spaced apart pillars formed by first and second cover supporting elements. By using only a limited amount of pillars, e.g. three or four, the position of the cover relative to the body can be defined in a more predictable manner. This particularly holds if the pillars are arranged in the outer corners of the package.