Resilient Connector for Wireless Package Antenna Contact
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Solution Overview
Problem
Conventional antenna on package (AoP) technologies face issues with weak bonding between metal vias and SMD jumper devices due to laser drill damage or oxidation, leading to unstable resistance and low manufacturing yield, especially as package sizes shrink, making it difficult to fill via openings with copper paste effectively.
Innovation Solution
A wireless package design featuring a package substrate with RFIC chips, resilient connectors, and a molding compound, where the resilient connectors have a terminal bonded to a pad on the substrate with a horizontal contact portion and an oblique support portion, allowing direct contact with the antenna, and a molding process that ensures the top surface of the connectors is not covered by the molding compound, facilitating stable contact resistance and improved yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a laser drill process is used to form via openings in the molding compound, then the via openings can be created to connect the antenna to the SMD jumper device, but the Sn layer of the SMD jumper device is damaged or oxidized, resulting in weak bonding between Sn and Cu and unstable resistance
Solution Approach 1:
The invention extracts and eliminates the laser drill process from the manufacturing flow. Instead of using laser drilling to create via openings that damage the Sn layer, the patent uses a plating process that deposits copper directly onto the SMD jumper device surface through electrochemical reactions, avoiding thermal and mechanical damage entirely.
Solution Approach 2:
The invention replaces the mechanical/thermal laser drilling system with an electrochemical plating system. The copper paste printing and firing process uses electrochemical deposition to form metal vias, substituting the harmful laser-based mechanical removal process with a gentler chemical deposition process that preserves the integrity of the SMD jumper device Sn layer.
2Volume of moving object
If the package size is reduced, then the wireless package becomes more compact and integrated, but the dimension of the via opening shrinks making it difficult to completely fill the via opening with copper paste
Solution Approach 1:
The invention changes the physical and chemical parameters of the copper deposition process. By using electrochemical plating with controlled current density, temperature, and plating solution composition, the process can deposit copper with high precision into very small via openings, achieving complete filling even in miniaturized packages where traditional printing methods fail.
Solution Approach 2:
The invention performs preliminary preparation of the via opening surfaces through cleaning and activation processes before copper deposition. This preliminary action ensures that the SMD jumper device surface and via walls are properly prepared to receive and bond with the copper paste, enabling complete and reliable filling of reduced-dimension via openings in compact packages.
3Ease of manufacture
If the Sn layer of the SMD jumper device is exposed to the laser drill process, then via openings can be formed, but the Sn layer becomes damaged or oxidized leading to weak bonding and low manufacturing yield
Solution Approach 1:
The invention converts the potential harm of exposing the Sn layer to harsh processes by completely avoiding such exposure. Instead of trying to protect the Sn layer during laser drilling, the patent uses a copper plating process that works harmoniously with the Sn layer, using it as a substrate for electrochemical copper deposition, thereby turning the Sn layer from a vulnerable target into an active participant in the beneficial bonding 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 solution provides stable contact resistance and improved manufacturing yield by ensuring direct contact between the antenna and the resilient connectors, reducing the deviation in resistance distribution and enhancing the reliability of the wireless package.
Implementation Method 1
the resilient connector has a terminal bonded to a pad on the top surface of the package substrate, a horizontal contact portion, and an oblique support portion being integrally coupled to the horizontal contact portion and extending between the horizontal contact portion and the terminal
Data Source
AI summary
The present invention discloses a wireless package with a resilient connector for connecting a substrate to an antenna. The antenna is disposed directly on a top surface of a molding compound of the wireless package. The resilient connector has a lower terminal bonded to the substrate, a horizontal contact portion, and an oblique support portion integrally extending between the horizontal contact portion and the lower terminal. The horizontal contact portion has a flat top surface that is coplanar with the top surface of the molding compound and is in direct contact with the antenna such that the contact resistance distribution is concentrated and the production yield of the wireless package is improved.