Contactless Wafer Testing via Wireless Voltage Evaluation
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Solution Overview
Problem
Contactless testing of wafers for integrated circuit fabrication lacks precision, as traditional methods can damage delicate structures and wireless monitoring is less precise compared to traditional testing methods.
Innovation Solution
A contactless on-wafer testing system that uses a voltage source to generate a supply voltage wirelessly, a reference generator to produce a known reference voltage, and a voltage evaluation component to modify the test component's response, allowing for precise determination of the supply voltage magnitude through a ramping signal and duty cycle analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If contactless testing is used to avoid damage to delicate wafer structures, then the wafer structures are protected from damage, but the precision of testing is reduced
Solution Approach 1:
The patent introduces an intermediary voltage evaluation component that acts as a mediator between the wireless power source and the test component. This intermediary circuitry converts wireless power signals into stable supply voltage and generates reference voltages, enabling precise voltage-based measurements without physical contact. The intermediary components include voltage regulators, reference voltage generators, and evaluation circuits that process the wireless power to create measurable electrical characteristics.
Solution Approach 2:
The patent changes the testing parameter from direct physical measurement to electrical parameter measurement (voltage magnitude). By converting the test into an electrical parameter measurement through the voltage evaluation component, the system achieves both contactless operation and high precision. The voltage magnitude, which can be precisely measured through duty cycle analysis of the ramping signal, serves as the test parameter that reflects wafer characteristics without physical contact.
2Ease of operation
If wireless power transmission is used to enable contactless testing, then contactless operation is achieved, but the power transmission precision is insufficient
Solution Approach 1:
The patent implements feedback mechanisms through the voltage evaluation component that continuously monitors the supply voltage and adjusts the ramping signal accordingly. The system uses the duty cycle of the test component as feedback to determine the actual supply voltage magnitude. This feedback loop ensures that despite the inherent imprecision of wireless power transmission, the system can accurately determine the voltage magnitude and maintain precise testing.
Solution Approach 2:
The patent applies preliminary action by generating a reference voltage from the supply voltage itself before the actual testing begins. The reference voltage generator creates a known reference value that can be used for comparison during testing. This preliminary preparation of reference values enables subsequent precise measurements of the supply voltage magnitude through duty cycle analysis, compensating for the imprecision of wireless power transmission.
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
Enables precise and non-destructive testing of wafer characteristics by accurately determining the supply voltage magnitude and voltage across devices under test, enhancing manufacturing quality control without damaging the wafer structures.
Implementation Method 1
a voltage source wirelessly receives power from an external source and converts the signal transmitted from the transmitter into the supply voltage
Implementation Method 2
the behavior of the test structure is evaluated via remote monitoring of high frequency emissions (e.g., microwave or RF emissions) from the test structure
Data Source
AI summary
Systems and methods are provided for contactless testing of a wafer containing at least one integrated circuit. A test component responds to a supply voltage to indicate at least one property of the wafer. A voltage source wirelessly receives power from an external source and produces the supply voltage. A reference generator generates a reference voltage, having a known magnitude, from the supply voltage. A voltage evaluation component modifies the response of the test component as to represent a magnitude of the supply voltage.