RFID Tag Antenna With Back-Side Wafer Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of RFID tags faces challenges due to the small size of ICs and contact pads, requiring high accuracy in antenna manufacturing and assembly, which increases production costs and complexity.
Innovation Solution
The RFID tag design incorporates an antenna with first and second antenna portions and an RFID chip positioned between them, using a semiconductor substrate with a planar conductor to facilitate radio frequency signal communication, eliminating the need for conductors through the substrate and improving alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all contact pads are placed on the active side of the silicon wafer to enable RFID circuit formation, then the RFID circuit can be manufactured using standard CMOS processes, but the placement accuracy requirement increases significantly due to small IC sizes (0.2-0.4mm)
Solution Approach 1:
The patent moves contact pads from the active side (2D plane) to the back side of the wafer, utilizing the third dimension (depth/thickness) to resolve the placement accuracy problem. This allows antenna connections to be made from the back side, eliminating the need for high-precision placement on the small active side contact pads.
Solution Approach 2:
The patent separates the contact pad locations into two distinct sides: the active side for RFID circuit formation and the back side for antenna connections. This segmentation allows each side to be optimized independently, with the back side providing larger, more easily placed contact areas.
2Device complexity
If contact pads are made smaller to accommodate small IC sizes, then more components can be integrated, but the difficulty of accurate placement increases
Solution Approach 1:
By moving contact pads to the back side of the wafer, the patent creates larger contact areas that are easier to place accurately, while the active side maintains high integration density with smaller components. The dimensionality change allows both requirements to be satisfied simultaneously.
3Manufacturing precision
If high accuracy is required during antenna manufacturing and assembly, then proper contact alignment can be achieved, but production costs increase
Solution Approach 1:
The patent reduces alignment accuracy requirements by enabling back-side connections, which provide larger tolerance margins. This dimensional approach simplifies the assembly process and reduces production costs by eliminating the need for high-precision alignment equipment and processes.
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
This configuration enhances data communication efficiency and reduces production costs by simplifying the assembly process and improving alignment precision, while maintaining effective radio frequency signal transmission.
Implementation Method 1
The semiconductor substrate has a lower surface area that faces the first antenna portion and communicates data, carried by radio frequency signals, between the first antenna portion and the radio frequency communication circuit
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A radio frequency communication circuit includes an antenna having a conductor and a semiconductor chip having a lower substrate surface coupled with the conductor to pass data carried by radio frequency signals to a radio frequency communication circuit in an active layer on an upper surface of the substrate. Accordingly, communications are facilitated via the substrate and can alleviate the need to use through-substrate connectors and further facilitate placement of the chip on the antenna. Application to an RFID tag (300).