Apertured Probe Card for Microscopy Access During Electrical Probing
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Solution Overview
Problem
Conventional probe cards for microelectronic devices obstruct top-down microscopy due to their significant physical bulk, preventing simultaneous high-bandwidth electrical probing and physical access to the device under test.
Innovation Solution
A probe card with a planar dielectric substrate, high-speed conductive traces, inner contact pads, and an aperture extending through the substrate, allowing unobstructed physical and optical access while maintaining electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional probe card with significant physical bulk is used, then electrical connectivity to the device under test is achieved, but physical and optical access to the device surface is obstructed
Solution Approach 1:
The probe card is segmented into distinct functional zones: an aperture region providing unobstructed access to the device surface, and peripheral contact pad regions for electrical connectivity. This segmentation allows the card to simultaneously provide both optical access and electrical probing without mutual interference.
Solution Approach 2:
The aperture is extracted as a distinct feature from the conventional solid probe card structure. By removing material to create this through-opening, the design eliminates the physical bulk that previously obstructed access to the device surface, while maintaining electrical connectivity through the surrounding contact pads.
2Strength
If a thick probe card structure is used, then mechanical strength and electrical routing are improved, but microscopy resolution and physical access are degraded
Solution Approach 1:
The design transitions from a purely two-dimensional planar contact structure to a three-dimensional aperture structure. The aperture extends through the thickness of the probe card, creating a vertical dimension of access that allows microscopy probes to reach the device surface from the front side without being blocked by the card's thickness.
Solution Approach 2:
The probe card exhibits local quality differentiation: the aperture region provides open access for microscopy, while the surrounding areas maintain structural integrity and electrical functionality. This localized differentiation allows different regions of the same component to serve different functions optimally.
3Reliability
If conventional probe card architecture is used, then electrical probing capability is maintained, but simultaneous in-situ microscopy is prevented
Solution Approach 1:
The probe card is designed with multi-functionality to simultaneously perform electrical probing and facilitate microscopy. The aperture enables optical access while the surrounding contact pads maintain electrical connectivity, allowing both functions to operate concurrently on the same device without requiring separate instrumentation setups.
Data Source
AI summary
An interface probe card includes a planar dielectric substrate of a cryogenic-compatible material having a first major surface and an opposite second major surface. Disposed on the first major surface is a plurality of high-speed conductive traces. A plurality of inner contact pads, also on the first major surface, are electrically connected to the conductive traces and arranged in a geometric pattern that defines an interior region. A plurality of metallic bumps protrude from the inner contact pads. Located within the interior region defined by the geometric pattern is an aperture that extends entirely through the planar dielectric substrate from the first major surface to the second major surface, providing an unobstructed line-of-sight path.