Probe Card Pressure Differential Non-Contact Signal Coupling
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Solution Overview
Problem
Existing non-contact probe cards for semiconductor wafer inspection face challenges with signal attenuation and interference when using capacitive or inductive coupling, particularly due to distance-dependent signal strength and adjacent electrode interference.
Innovation Solution
A probe card design that creates a pressure differential between two sealed spaces, with the first space having higher pressure than the second, allowing the thin film substrate to expand and bring non-contact electrodes closer to the semiconductor wafer, thereby enhancing electromagnetic coupling and stabilizing signal transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If non-contact coupling (capacitive or inductive) is used for signal transmission, then the probe card is not limited by weight and can accommodate more electrodes, but signal strength is notably attenuated and adjacent electrodes cause interference
Solution Approach 1:
A magnetic sheet is introduced as an intermediary component between the inductive coupling electrodes on the probe card and the semiconductor wafer. This magnetic sheet enhances the magnetic field coupling efficiency, thereby strengthening the inductive coupling signal transmission and reducing interference between adjacent electrodes while maintaining the weight advantage of non-contact coupling.
2Area of stationary object
If the distance between non-contact electrodes and wafer is increased, then coverage area is expanded, but signal strength is attenuated in inverse proportion to distance
Solution Approach 1:
The magnetic sheet changes the electromagnetic coupling parameters by concentrating and enhancing the magnetic field between the electrodes and wafer. This allows for expanded coverage area while maintaining adequate signal strength through improved magnetic coupling efficiency rather than relying solely on reduced distance.
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 design improves signal stability and strength by increasing electromagnetic coupling, allowing for effective non-contact inspection of semiconductor chips, even when electrodes are spaced apart, and is versatile enough to accommodate varying wafer types.
Implementation Method 1
a first sealed space, the pressure of which is reduced to be lower than the atmospheric pressure, by a wiring substrate and a thin film substrate having a bump electrode or the like, and a second sealed space, the pressure of which is reduced to be lower than the atmospheric pressure, by a thin film substrate and an inspection target semiconductor wafer, in which the pressure of the first sealed space is made higher than the pressure of the second sealed space
Implementation Method 2
a non-contact electrode to be electrically connected to the pad electrodes by capacitive coupling or inductive coupling
Implementation Method 3
a non-contact electrode to be electrically connected to the pad electrodes by capacitive coupling or inductive coupling
Data Source
AI summary
A probe card has a thin film substrate having projection electrodes on a first surface facing the semiconductor wafer and at a position facing the pad electrodes, a non-contact electrode, and first electrodes provided a second surface opposite to the first surface; and a wiring substrate having second electrodes disposed at a side opposite to the semiconductor wafer in the thin film substrate and at a position facing the first electrodes. The wiring substrate and the thin film substrate form a first sealed space and the thin film substrate and the semiconductor wafer form a second sealed space. By reducing the pressure in the first and the second sealed space, the first and the second electrodes are brought into close contact with each other and the pad electrodes and the projection electrodes are brought into close contact with each other, and the pressure of each of the first and second sealed space can be independently adjusted.