Localized Vacuum Seal for E-Beam IC Fault Analysis
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Solution Overview
Problem
Existing electron beam diagnostic systems for ICs require hundreds to thousands of high-speed electrical feedthroughs to activate modern ICs inside an SEM chamber, which is cumbersome and slow, especially as the complexity and transistor count of ICs increase, necessitating specialized connection equipment and a high-vacuum environment.
Innovation Solution
A method and apparatus that use a scanning electron microscope (SEM) with a sealed volume around the IC back-side to create a partial vacuum, allowing electrical connections to be made outside the vacuum chamber, enabling electron beam probing of ICs in a low-vacuum environment, thus eliminating the need for numerous vacuum feedthroughs and allowing ICs to be tested in their normal operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-vacuum environment is used for SEM operation, then electron beam operation is enabled, but hundreds to thousands of high-speed electrical feedthroughs are required to activate modern ICs
Solution Approach 1:
The patent divides the vacuum environment into two separate zones: a high-vacuum zone for the SEM column and electron source, and a low-vacuum or atmospheric zone for the IC testing area. This segmentation allows the electron beam to operate in high vacuum while the IC is activated in a separate zone that does not require vacuum conditions, eliminating the need for numerous feedthroughs.
Solution Approach 2:
The patent extracts the IC activation function from the high-vacuum environment and places it in a separate low-vacuum chamber. The IC is mounted on a stage that can be positioned in the low-vacuum zone for electrical activation, then moved to the high-vacuum zone for electron beam analysis, or the electron beam is directed through a localized evacuated volume at the IC location.
2Ease of operation
If hundreds to thousands of high-speed electrical feedthroughs are used to activate ICs inside SEM chamber, then IC activation is enabled, but the process becomes cumbersome and slow
Solution Approach 1:
By segmenting the vacuum chamber into high-vacuum and low-vacuum zones, the patent enables IC activation to occur in the low-vacuum zone using standard electrical connections without requiring specialized feedthroughs. This eliminates the cumbersome setup process and reduces time required for activating complex ICs.
3Measurement precision
If a localized evacuated volume is created around IC back-side, then vacuum quality for SEM operation is maintained, but the test setup is simplified and access to ICs is improved
Solution Approach 1:
The patent creates a localized evacuated volume specifically around the IC back-side area where the electron beam interacts with the IC. This localized vacuum maintains sufficient vacuum quality for high-resolution SEM operation at the interaction point, while the rest of the chamber can be at atmospheric pressure, allowing simplified test setup and improved access to the IC.
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 approach simplifies the test setup, reduces equipment and labor costs, and improves access to ICs, enabling faster and more efficient fault analysis by allowing multiple test tools to be used, while maintaining sufficient vacuum quality for high-resolution SEM operation.
Implementation Method 1
voltage measurements from active circuits using voltage contrast principles
Implementation Method 2
evacuating the sealed volume
Data Source
AI summary
Provided are new techniques for fault analysis in IC semiconductor devices, including system designs and methods to enable the probing of circuitry within an IC device under test (DUT) using electron beam (e-beam) techniques while the DUT is being stimulated electrically, or while the device is active on its own or within a host system mounted in a circuit board or other module. The DUT could be a packaged IC, or an IC in some unpackaged form. To create a local evacuated volume immediately outside the e-beam tool, a sealing element is sealed against or around the DUT for a localized seal. Such an arrangement obviates the need for vacuum feedthroughs of possibly thousands of signals required to operate and monitor the DUT, and further enables probing of a DUT while it is operating in its normal environment, such as installed on a circuit board in its system, or on a tester.