Flexible Membrane Probe Card for High Frequency Signal Integrity
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Solution Overview
Problem
Probe cards used for testing semiconductor wafers face challenges in carrying high-frequency signals without adding noise, and there is a risk of breaking contact probes and pads due to increased stiffness from reduced probe length, leading to potential damage during testing.
Innovation Solution
A probe card design featuring a flexible membrane with a damping structure and a sliding contact area, along with a pressing element that applies tension to the membrane, ensuring mechanical and electrical contact while preventing deformation and breaking, and optimizing the contact force to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of contact probes is reduced to carry high-frequency signals, then signal quality is improved, but the stiffness of probes increases leading to higher risk of breaking
Solution Approach 1:
The patent employs a flexible membrane structure to support the contact probes, allowing the probes to maintain reduced length for high-frequency signal carrying while the flexible membrane provides mechanical compliance to prevent probe breaking. The membrane acts as a compliant substrate that absorbs mechanical stress.
Solution Approach 2:
The patent changes the mechanical parameters of the probe support system by introducing a flexible membrane with specific elastic properties. This allows the contact probes to have optimal electrical parameters (short length) while the support structure provides necessary mechanical protection through controlled flexibility.
2Reliability
If the contact force is increased to ensure good electrical contact, then contact reliability is improved, but the risk of breaking contact pads increases
Solution Approach 1:
The patent optimizes the contact force parameter by using a flexible membrane that provides controlled elastic pressure. The membrane's elastic properties ensure sufficient contact force for reliable electrical connection while limiting the maximum force to prevent pad damage.
Solution Approach 2:
The probe card uses a composite structure combining rigid contact probes with a flexible membrane support. This composite design allows the probes to maintain stable electrical contact through the membrane's elastic pressure while the flexibility prevents excessive force that could damage the pads.
3Stability of the object's composition
If a rigid support structure is used to hold contact probes, then structural stability is improved, but the ability to accommodate deformation and movement is reduced
Solution Approach 1:
The patent replaces rigid support structures with a flexible membrane that can deform to accommodate probe movement and wafer surface variations. The membrane maintains structural integrity while providing the necessary compliance for reliable contact during the probing process.
Solution Approach 2:
The patent transitions from a static rigid support to a dynamic flexible membrane system that can adapt its shape and stiffness during operation. The membrane allows controlled deformation to accommodate probe deflection and wafer positioning variations while maintaining stable electrical contact.
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 solution effectively carries high-frequency signals without noise, reduces the risk of probe and pad breakage, and maintains the integrity of the flexible membrane, ensuring reliable testing operations.
Implementation Method 1
apt to stretch the flexible membrane along a longitudinal direction thereof, so as to ensure the integrity thereof even in case of different repositioning operations of the same
Implementation Method 2
A probe card design featuring a flexible membrane with a damping structure and a sliding contact area
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A probe card for a testing apparatus of electronic devices is described, comprising at least one support plate (33), as well as a flexible membrane (32) and a plurality of contact probes (35) associated with a first face (F1) thereof, the contact probes (35) being apt to abut onto a plurality of contact pads (34A) of a device under test (34') integrated on a semiconductor wafer (34) and being apt to carry high frequency signals, the card comprising at least one sliding contact area (36) including in turn first contact pads (36A) formed on the support plate (33) and second contact pads (36B) formed on the flexible membrane (32) at a peripheral portion (32C) thereof apt to come in pressing contact onto the support plate (33) at the sliding contact area (36) as well as at least one pressing element (37) in pressing contact onto the peripheral portion (32C) of the flexible membrane (32) at the sliding contact area (36) so as to put in pressing contact the second contact pads (36B) onto the first contact pads (36A) providing an electrical and mechanical contact between the flexible membrane (32) and the support plate (33).