Probe Card Expansion Gap for Thermal Stress Relief
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Solution Overview
Problem
Semiconductor probe cards face alignment issues due to thermal expansion mismatches between materials, leading to compressive stresses and deformation, which cause misalignment and incorrect test results during multisite testing across varying temperatures.
Innovation Solution
Incorporating expansion gaps in the probe card assembly, specifically between the probe core and plate, or between the tube and plate, to reduce compressive stresses and maintain flatness, allowing for precise alignment and reducing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the probe card plate and probe core are bonded together to maintain structural integrity, then the assembly remains rigid and stable, but thermal expansion mismatches cause compressive stresses and deformation leading to misalignment
Solution Approach 1:
The probe card assembly is segmented into distinct components (probe card plate, probe core, tube) that can expand independently. The expansion gap creates a discontinuity that allows each component to maintain its own dimensional stability while accommodating thermal expansion differences, preventing stress buildup that would cause misalignment.
Solution Approach 2:
The expansion gap acts as an intermediary element between the probe card plate and probe core. This gap serves as a buffer zone that absorbs thermal expansion mismatches, allowing the two components to remain connected while accommodating differential expansion without transmitting harmful stresses.
2Manufacturing precision
If the probe card is designed to remain substantially flat over varying temperatures for multisite testing, then alignment between probes and wafer pads is maintained, but thermal expansion mismatches between materials cause stress buildup and deformation
Solution Approach 1:
The expansion gap is designed in advance as a cushioning feature that anticipates thermal expansion mismatches. By providing this pre-planned accommodation space, the design prevents stress buildup before it can cause deformation, allowing the probe card to maintain flatness across the intended temperature range.
3Reliability
If materials with different coefficients of thermal expansion are used for the probe card plate and probe core, then electrical isolation is improved, but thermal expansion mismatches cause stress buildup and potential shifting between components
Solution Approach 1:
The assembly is segmented to allow independent thermal expansion of each material component. The expansion gap creates physical separation that prevents the transmission of thermal stresses between components with different expansion coefficients, maintaining both electrical isolation and component stability.
4Strength
If bonding is used to attach the probe core to the probe card plate, then the assembly remains mechanically secure, but deformation and fracture can occur when testing across large temperature ranges
Solution Approach 1:
The expansion gap serves as an intermediary that decouples the mechanical stress transmission between the bonded components. While the bond maintains mechanical security, the gap prevents the transmission of thermal expansion stresses that would otherwise cause deformation or fracture across large temperature ranges.
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 expansion gaps effectively minimize deformation of the probe card plate, maintaining alignment and reducing the risk of misalignment, thereby improving test accuracy and reducing the need for repeated testing and costly replacements.
Implementation Method 1
The materials are generally selected based on the low thermal expansion of silicon and ceramics in order to provide relatively high electrical isolation. The materials, however, generally have different coefficients of thermal expansion, which can cause a buildup of stress between the components
Data Source
AI summary
A probe card assembly is disclosed. The probe card assembly includes a probe card plate, a probe core, and an expansion gap defined in the probe card plate. The probe core includes a bonding portion for fixing the probe core to the probe plate. The expansion gap surrounds the probe core. Another probe card assembly is disclosed. The another probe card assembly includes a probe card plate, a tube, and a probe core. The tube is configured to be inserted into an opening of the probe card plate and configured to be securely fixed to the probe card plate. The probe core includes a bonding portion for fixing the probe core to the tube.