Probe Alignment Sensing Structure Using Shared Elements
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Solution Overview
Problem
Existing sensing structures for aligning probes with integrated circuit pads on substrates are inadequate in determining probe position and direction due to small voltage differences and sensitivity to poor electrical contact, leading to incorrect alignment and increased risk of damaging the pads.
Innovation Solution
A sensing structure with multiple sensing regions connected through shared sensing elements, creating significant voltage differences between adjacent regions to unambiguously determine probe position, and using a compact design with reduced number of elements to enhance reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensing structures with individual sensing elements for each sensing region are used, then the probe position can be detected, but the voltage differences between adjacent regions are small and the structure is complex
Solution Approach 1:
The patent combines multiple sensing elements into shared sensing elements that are common to multiple sensing regions. Instead of having individual sensing elements for each sensing region, the invention uses sensing elements that are shared between adjacent sensing regions, thereby reducing the total number of sensing elements and simplifying the overall sensing structure while maintaining the ability to detect probe position accurately through voltage differences.
Solution Approach 2:
The shared sensing elements serve multiple functions by being common to multiple sensing regions. Each sensing element participates in detecting the probe position for multiple adjacent sensing regions simultaneously, making the sensing elements universal and multi-functional rather than dedicated to a single sensing region.
2Manufacturing precision
If sensing structures with many sensing elements are used, then probe alignment can be determined, but the structure occupies large area and reduces manufacturing reliability
Solution Approach 1:
The patent merges multiple sensing elements into shared sensing elements that serve multiple sensing regions. This consolidation reduces the total number of sensing elements required, thereby reducing the overall area occupied by the sensing structure while maintaining sufficient probe alignment accuracy through the voltage differences generated by the shared elements.
Solution Approach 2:
The sensing structure is segmented into multiple sensing regions that share common sensing elements. This segmentation allows the sensing function to be distributed across multiple regions while using fewer total elements, reducing the overall area requirement while maintaining detection capability across the entire sensing structure.
3Reliability
If traditional sensing structures are used, then probe contact can be detected, but the structure is sensitive to poor electrical contact and gives incorrect alignment results
Solution Approach 1:
The patent implements a sensing mechanism where voltage differences are measured between sensing regions connected through shared sensing elements. This creates a feedback system where the electrical potential distribution provides information about probe contact quality, allowing the system to distinguish between genuine alignment signals and artifacts caused by poor electrical contact.
Solution Approach 2:
The shared sensing elements create equipotential regions that help stabilize the electrical measurement. By connecting multiple sensing regions through shared elements, the structure reduces the impact of contact resistance variations, as the voltage measurement reflects the relative potential differences rather than absolute potentials that are sensitive to contact quality.
4Measurement precision
If dummy structures with conducting regions surrounded by non-conductive regions are used, then alignment can be verified, but the probability of damaging passivation increases due to improper probing
Solution Approach 1:
The patent uses sensing structures that provide preliminary alignment verification before actual probing of the integrated circuits. The sensing regions with shared elements allow the probe card to be positioned and aligned correctly in advance, ensuring that subsequent probing operations are accurately targeted and reduce the risk of damaging the passivation or misaligning with the actual circuit pads.
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 proposed sensing structure effectively determines probe alignment and direction with increased accuracy, even under non-optimal contact conditions, reducing the risk of pad damage and improving testing precision.
Implementation Method 1
at least one first sensing element. Each of the at least one sensing element is connected, for example directly connected, to two sensing regions such that for each sensing region a different value of an electrical parameter is measurable between said sensing region and a first reference voltage
Data Source
AI summary
A sensing structure is presented for use in testing integrated circuits on a substrate. The sensing structure includes a probe region corresponding to a conductive region for connecting to the integrated circuit. A first sensing region at least partially surrounds the probe region. A plurality of sensing elements connects in series such that a first of the plurality of sensing elements has two terminals respectively connected to the first sensing region and the probe region. And a second of the plurality of sensing elements has two terminals respectively connected to the probe region and a first reference potential.