Wafer Level Packaging Cap With Plated Connection Grooves
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Solution Overview
Problem
Conventional wafer level packaging caps require thick substrates to prevent damage, leading to increased size and manufacturing costs due to the need for deep connection holes, which are time-consuming and costly to fabricate, and result in unstable metal connections.
Innovation Solution
A wafer level packaging cap with a thin cap substrate featuring connection grooves plated with metal, where the inner surfaces are oxidized to form a seed layer, allowing for stable metal connection parts that penetrate the substrate, and a supporting film is used to reinforce the wafer during fabrication, reducing thickness and fabrication time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick cap substrate is used to prevent damage, then the strength and reliability are improved, but the size increases and manufacturing costs increase due to deep connection holes
Solution Approach 1:
The patent employs a thin cap substrate (50-150 μm) instead of a thick substrate, utilizing a supporting film and connection groove structures to provide the necessary mechanical strength. This approach maintains substrate strength while significantly reducing the thickness and overall size of the packaging cap.
Solution Approach 2:
The connection holes are segmented into connection grooves with metal connection parts formed through plating processes. This segmentation allows the use of thinner substrate material while maintaining structural integrity through the distributed metal reinforcement elements within the grooves.
2Reliability
If deep connection holes are fabricated to penetrate thick substrates, then electrical connectivity is achieved, but the fabrication time increases and manufacturing costs increase
Solution Approach 1:
The patent changes the geometric parameters of the connection structure by using shallower connection grooves instead of deep penetrating holes. The groove depth is optimized to be sufficient for electrical connectivity while minimizing fabrication time and material removal, thereby reducing overall manufacturing time.
Solution Approach 2:
The connection grooves are formed and metal connection parts are plated before the final substrate thinning process. This preliminary action ensures that the electrical connectivity structure is established while the substrate is still thick and easier to handle, reducing fabrication time and improving process reliability.
3Reliability
If deep connection holes are drilled through thick substrates, then metal connections are formed, but the manufacturing cost increases and connection stability decreases
Solution Approach 1:
The patent uses a composite structure combining the cap substrate material (such as glass or ceramic) with metal connection parts formed by plating the connection grooves. This composite approach provides stable electrical connections while using thinner substrate material, reducing manufacturing costs associated with deep hole drilling and material removal.
Solution Approach 2:
The metal connection parts plated in the connection grooves serve as intermediary elements that provide stable electrical connectivity between the top and bottom surfaces of the substrate. These intermediaries eliminate the need for deep through-holes, reducing manufacturing complexity and cost while improving connection reliability.
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 enables the fabrication of thinner, more stable packaging caps with reduced manufacturing costs and time, enhancing electrical stability and allowing for miniaturization and integration of devices.
Implementation Method 1
the inner surfaces are oxidized to form a seed layer, allowing for stable metal connection parts that penetrate the substrate
Implementation Method 2
connection parts formed to penetrate from the bottom surface to a top surface of the cap substrate... formed by plating connection grooves
Data Source
AI summary
A wafer level packaging cap for covering a device wafer with a device thereon and a fabrication method thereof are provided. The method includes operations of forming a plurality of connection grooves on a wafer, forming a seed layer on the connection grooves, forming connection parts by filling the connection grooves with a metal material, forming cap pads on a top surface of the wafer to be electrically connected to the connection parts, bonding a supporting film with the top surface of the wafer on which the cap pads are formed, forming a cavity on a bottom surface of the wafer to expose the connection parts through the cavity, and forming metal lines on the bottom surface of the wafer to be electrically connected to the connection parts.