Probe Card Floating Connectors Thermal Expansion
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Solution Overview
Problem
Probe cards used for testing electronic devices face challenges in maintaining effective contact at high temperatures due to thermal expansion of materials with different coefficients of expansion, leading to deformation and potential loss of contact with the device being tested.
Innovation Solution
The probe card design incorporates connecting elements with clearance, allowing for floating housing between a supporting plate and an interface plate, which compensates for thermal expansion without affecting the positioning of the probe head, ensuring stable contact and operation even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If connecting elements are rigidly fixed between supporting plate and interface plate, then structural stability is improved, but thermal expansion causes deformation and loss of contact at high temperatures
Solution Approach 1:
The connecting elements are designed with clearance fits instead of rigid fixed connections, allowing them to move dynamically relative to the supporting plate and interface plate. This dynamic capability enables the structure to adapt to thermal expansion while maintaining contact integrity, resolving the contradiction between structural stability and contact reliability at high temperatures.
Solution Approach 2:
The invention changes the physical parameters of the connecting elements by providing clearance fits with specific dimensional tolerances. This parameter change allows the connecting elements to accommodate thermal expansion differences between materials, maintaining both structural stability and contact integrity under varying temperature conditions.
2Adaptability or versatility
If connecting elements with clearance are used between supporting plate and interface plate, then thermal expansion compensation is improved, but positioning precision of probe head may be affected
Solution Approach 1:
The clearance fit is applied locally only to the connecting elements between the supporting plate and interface plate, not to the probe head positioning interfaces. This localized application of clearance allows thermal expansion compensation where needed while maintaining precise positioning where required, resolving the contradiction between adaptability and manufacturing precision.
Solution Approach 2:
The probe card structure is segmented into distinct functional zones: the connecting elements with clearance for thermal compensation, and the probe head mounting interfaces with tight tolerances for precise positioning. This segmentation allows different parts of the structure to have different quality requirements, simultaneously achieving thermal expansion compensation and positioning precision.
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 design effectively maintains the probe head's position and contact integrity during thermal expansion, preventing deformation and ensuring reliable testing at high temperatures, thus overcoming the limitations of existing technologies.
Implementation Method 1
thermal expansion of materials with different coefficients of expansion
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Herein described is a probe card for an apparatus for testing electronic devices, of the type comprising at least one probe head (21) which houses a plurality of contact probes (22), each contact probe (22) having at least one contact tip suitable to abut against contact pads of a device to be tested, as well as a supporting plate (23) of such probe head (21) associated with a stiffener (24, 24') via an interface plate (25). Suitably, the probe card (20) comprises a plurality of connecting elements (27) with clearance between the supporting plate (23) and the interface plate (25) housed in a floating manner in a plurality of respective seats (28) made in the supporting plate (23) and a plurality of further connecting elements (27') without clearance between the interface plate (25) and the stiffener (24).