Apparatus for cooling a sputtering target
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Solution Overview
Problem
Existing sputtering technologies struggle to efficiently cool sputtering targets with melting points below 100°C without causing liquefaction, and existing cooling methods require complex contamination prevention measures.
Innovation Solution
A cooling apparatus using a refrigerant that changes state within a closed cooling circuit, comprising a heat sink, compressor, and pressure stage, to efficiently transfer thermal energy while minimizing refrigerant heating and ensuring all components are vaporized before entering the compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coolant flows through a cooling channel in direct contact with the sputtering target, then heat dissipation is improved, but the coolant may cause contamination or insufficient cooling for low-melting-point materials
Solution Approach 1:
The cooling system is segmented into separate functional zones: a cooling channel for heat removal and an evaporation zone for enhanced cooling. The cooling channel is positioned adjacent to but separate from the sputtering target surface, preventing direct contact between coolant and target material while maintaining effective heat transfer through the heat sink structure.
Solution Approach 2:
A heat sink acts as an intermediary between the sputtering target and the coolant. The heat sink absorbs heat from the target and transfers it to the coolant flowing through the cooling channel, eliminating direct contact between coolant and target material while maintaining efficient thermal coupling.
2Temperature
If conventional cooling methods are used for targets with melting points below 100°C, then cooling is provided, but liquefaction of the target occurs
Solution Approach 1:
The system utilizes phase transition of the coolant (evaporation from liquid to vapor) to achieve enhanced cooling effect. The evaporation zone allows the coolant to absorb additional latent heat of vaporization, providing intensive cooling capability that can maintain low-melting-point target materials below their liquefaction temperature.
Solution Approach 2:
The cooling system operates with periodic evaporation cycles where coolant is supplied to the evaporation zone, evaporates to provide intensive cooling, and is then replenished. This periodic action allows for dynamic temperature control that can respond to varying heat loads while maintaining target temperature below critical thresholds.
3Object-affected harmful factors
If complex contamination prevention measures are implemented, then contamination is reduced, but device complexity increases
Solution Approach 1:
The harmful function of the coolant (potential contamination) is extracted and separated from the useful function (cooling). The coolant operates in a dedicated evaporation zone separated from the sputtering process zone, allowing it to perform intensive cooling without risking contamination of the target or deposition chamber.
Solution Approach 2:
The potential harmful effect of coolant evaporation (contamination risk) is converted into a beneficial intensive cooling mechanism. The evaporation process, which could potentially contaminate the chamber, is instead utilized as the primary cooling mechanism in a controlled zone, providing enhanced cooling capacity while the separation prevents contamination.
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 apparatus effectively cools sputtering targets with melting points below 100°C, preventing liquefaction and maintaining a stable sputtering process by utilizing a refrigerant that changes state, enhancing heat transfer and reducing compressor damage risks.
Implementation Method 1
a refrigerant flowing through the cooling channel undergoes at least a partial change in state from liquid to vapor or gas, predominantly within the cooling channel in the heat sink, due to the thermal energy introduced into the target and the heat sink using a sputtering process
Implementation Method 2
thermal energy is extracted from the environment of the refrigerant due to the change in state of the refrigerant
Implementation Method 3
a compressor by means of which the vapor components of the refrigerant which escape from the cooling channel of the heat sink are compressed and finally converted back to the liquid state
Implementation Method 4
a heat sink which has a contact surface by means of which a mechanical contact with the sputtering target is formed
Data Source
AI summary
An apparatus is provided for cooling a sputtering target comprising a heat sink for the sputtering target. The heat sink is traversed by a cooling channel. The cooling channel includes a fluid. A cooling channel outlet is connected to an inlet of a compressor. An outlet of the compressor is connected to the inlet of a pressure stage by a second pipe, a first portion of which extends through a first heat exchanger; the outlet of the pressure stage is connected to the cooling channel inlet by a third pipe; the fluid is a refrigerant having a boiling point of 0° C. or less at a pressure of 1 bar and a boiling point of −10° C. or less at a pressure of 0.7 bar; the pressure stage causes a pressure reduction of at least 2 bars on average from the pressure stage inlet to the pressure stage outlet.