Temperature-Forcing Head Using Bi-Phase Refrigerant Evaporation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature forcing systems for semiconductor devices face inefficiencies due to multiple heat exchangers, low heat transmission rates, and high thermal inertia, limiting the accuracy and speed of temperature control, especially during extreme temperature testing.
Innovation Solution
A bi-phase refrigerant-based temperature forcing system with a central unit and thermal heads, utilizing a compressor, condenser, and evaporator to directly evaporate refrigerant for efficient heat dissipation and rapid temperature switching, incorporating a thermoelectric cooler and heating elements for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional refrigeration system with two heat exchangers is used, then the system can cool the device, but the cumulative temperature differential is large and the temperature switching rate is limited
Solution Approach 1:
The patent extracts the intermediate heat exchanger from the conventional two-stage refrigeration system, using only a single heat exchanger directly coupled to the device under test. This eliminates the cumulative temperature differential problem and enables rapid temperature switching while maintaining cooling effectiveness.
Solution Approach 2:
The system pre-cools the heat transfer fluid to a temperature below the target device temperature before initiating the cooling process. This preliminary action allows the single heat exchanger to achieve the desired temperature differential without requiring a two-stage system, thereby improving temperature switching speed.
2Loss of energy
If forced convection heat transfer is used in the heat exchanger, then heat can be dissipated, but the heat transmission factor is low and limits temperature change rate
Solution Approach 1:
The patent utilizes phase transition of the heat transfer fluid (from liquid to vapor) within the heat exchanger. This phase change process provides extremely high heat transmission factors compared to forced convection, enabling rapid temperature changes while efficiently dissipating heat energy.
3Device complexity
If a single-stage refrigeration system is used, then the system is simpler, but the maximum cooling temperature is limited
Solution Approach 1:
The system pre-cools the heat transfer fluid to a temperature well below the target device temperature using a compressor and condenser arrangement. This preliminary cooling action enables a single-stage heat exchanger to achieve temperatures that would normally require a two-stage system, thereby maintaining simplicity while extending the cooling range.
4Loss of energy
If the heat transfer fluid has high heat capacity, then it can carry more heat, but the temperature switching rate is limited due to thermal inertia
Solution Approach 1:
The system exploits the phase transition from liquid to vapor in the heat exchanger, during which the fluid absorbs large amounts of heat (latent heat) without temperature change. This mechanism provides high heat carrying capacity during the phase change process while maintaining rapid response capability, overcoming the thermal inertia limitation of high heat capacity fluids.
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 system achieves rapid and accurate temperature control, allowing for switching between extreme temperatures at rates of 50-150°C/min, improving thermal efficiency and reducing material deformation considerations.
Implementation Method 1
the refrigerant is maintained in a liquid phase between the compressor and the flow control device and in a gaseous phase while flowing through the evaporator... causing at least some of said refrigerant to enter the evaporator in liquid phase, whereby it dissipates heat therefrom by evaporation
Implementation Method 2
a compressor, a condenser, a flow control device for inducing a pressure drop in said refrigerant... a corresponding bi-phase refrigerant is circulatable
Implementation Method 3
a compressor, a condenser, a flow control device for inducing a pressure drop in said refrigerant... maintaining said refrigerant in a liquid phase between the compressor and the flow control device
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A temperature-forcing system and method for controlling the temperature of an electronic device under test comprises a temperature-forcing head, including a face positionable in thermal contact with the device, and an evaporator, in direct or indirect thermal contact with the face; and a refrigerant circulation subsystem, including a compressor, a condenser, a flow control device for inducing a pressure drop in the refrigerant, and a conduit circuit through which the refrigerant is flowable. The subsystem cooperates with the evaporator so as to define at least one closed loop through which a corresponding bi-phase refrigerant is circulatable, so that, during circulation, the refrigerant is maintained in a liquid phase between the compressor and the flow control device and in a gaseous phase while flowing through the evaporator, The temperature of the device is therefore switchable by the head at a rapid rate of 50 to 150 degrees Celsius per minute.