Thermal Shielding Device for Probe Card Temperature Control
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Solution Overview
Problem
Probe cards in wafer testing are exposed to extreme temperatures due to thermal conduction and radiation, leading to mechanical and electrical issues, and existing solutions are costly and inefficient in maintaining a constant temperature.
Innovation Solution
A thermal shielding device with a channel system between thermally conductive plates and a heat-insulating intermediate layer, using air as the tempering fluid to maintain the probe card at a constant temperature, and featuring a countercurrent flow design for enhanced cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating devices are provided on the probe card to preheat it to the desired test temperature, then the probe card can be calibrated at the test temperature, but the cost increases significantly as heaters account for up to 80% of the probe card cost
Solution Approach 1:
The invention extracts the heating function from the probe card itself and relocates it to a separate heating device positioned beneath the probe card. This separation allows the probe card to be cooled passively while the heating function is provided independently, significantly reducing probe card costs while maintaining calibration capability.
Solution Approach 2:
The invention introduces a heating device as an intermediary component between the temperature-controlled chuck and the probe card. This intermediary provides the necessary thermal conditioning to the probe card without requiring integrated heaters, thereby reducing cost while maintaining reliability.
2Adaptability or versatility
If the probe card is exposed to extreme test temperatures through thermal conduction and radiation, then wafer testing can be performed at extreme temperatures, but mechanical and electrical problems occur on the probe card
Solution Approach 1:
The invention segments the thermal management function by separating the probe card from the extreme temperature environment using a shielding structure. The probe card is divided into a functional component that remains at stable temperature, while the shielding structure handles the extreme temperature exposure, thereby maintaining reliability.
Solution Approach 2:
The invention converts the harmful thermal radiation and conduction into a beneficial controlled heating process by using a heating device that provides uniform, controllable thermal exposure to the probe card without the asymmetric and excessive temperatures that cause damage. The harmful extreme temperatures are transformed into a controlled, beneficial thermal conditioning process.
3Productivity
If the chuck with the wafer is moved laterally and vertically below the needle head to reach all integrated circuits, then complete wafer coverage is achieved, but asymmetrical temperature distributions occur on the probe card
Solution Approach 1:
The invention creates an equipotential thermal environment for the probe card by using a heating device that provides uniform thermal exposure across the entire probe card surface. This ensures that all areas of the probe card, regardless of chuck position, experience the same temperature conditions, eliminating asymmetrical temperature distributions and maintaining stability.
4Reliability
If a thermal shielding device with channel system and heat-insulating intermediate layer is used to maintain constant probe card temperature, then the probe card remains at constant temperature avoiding asymmetrical distributions, but the device complexity increases
Solution Approach 1:
The invention uses a heat-insulating intermediate layer in the form of a thin film or shell structure that provides effective thermal shielding. This thin-film approach achieves the desired temperature stability with minimal added complexity compared to bulk insulation structures.
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 maintains the probe card at a constant temperature, avoiding asymmetrical temperature distributions and reducing heat conduction, while being cost-effective and easily retrofittable to existing wafer probers.
Implementation Method 1
The probe card is exposed to these extremely high or low test temperatures on the one hand due to thermal conduction via the contact needles
Implementation Method 2
a channel system between thermally conductive plates and a heat-insulating intermediate layer
Data Source
Figure 1
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Figure 4
AI summary
The present invention relates to a thermal shielding device for a probe card and a corresponding probe card assembly. The thermal shielding device comprises: a first and a second thermally conductive plate (P1, P2); a structured thermally insulating intermediate layer (Z), which is provided between the first and the second thermally conductive plate (P1, P2) and which forms a channel system (K) for a temperature-control fluid (TF), which channel system is bounded on a first side (S1) by the first plate (P1) and on a second side (S2) by the second plate (P2); a first inlet (FI) for the temperature-control fluid (TF) into the channel system (K) and a first outlet (FO) for the temperature-control fluid (TF) out of the channel system (K); and a feed-through opening (O) for feeding through a needle head (10) attached to the probe card (5).