Thermal conductive fluids for semiconductor component manufacturing

Abstract

This invention relates to the use of aliphatic diester-based thermal conductive fluids in the manufacture of semiconductor components.

Description

Technical Field

[0001] This application relates to the use of aliphatic diester-based heat transfer fluids in the manufacture of semiconductor components.

Background Art

[0002] Today, heat dissipation is a relevant topic in the design and manufacture of semiconductor components.

[0003] In this context, heat transfer fluids (HTFs) play an important role that significantly affects both the performance and quality of semiconductor components. These special fluids are actually essential for maintaining accurate temperature control, which is important for the various processes involved in semiconductor manufacturing.

[0004] In fact, semiconductor manufacturing involves a number of processes such as lithography, etching, doping, and deposition, and all of these processes require accurate temperature control. Heat transfer fluids ensure that these processes occur at optimal temperatures and minimize thermal fluctuations that can lead to defects in microelectronic structures.

[0005] Therefore, maintaining a stable temperature is essential for the consistent performance of semiconductor devices, and heat transfer fluids help avoid overheating or overcooling that can affect the electrical characteristics and performance reliability of components.

[0006] Therefore, there is a strong need to identify and develop new and improved heat transfer fluids that can meet the stringent requirements of semiconductor component manufacturing.

[0007] Today, the fluids known for liquid cooling in semiconductor manufacturing processes are special fluids, among which those containing PFAS (perfluorinated and polyfluorinated substances) have found wide applications.

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, the applicant noted that even though special fluids, such as those containing PFAS, possess satisfactory properties that guarantee performance characteristics for semiconductor manufacturing, such as low kinematic viscosity, high dielectric constant, and high volume resistivity over a wide operating temperature range from boiling point to pour point, these fluids have recently demonstrated technical and application limitations.

[0009] In fact, PFAS tend to be highly volatile, and this volatility leads to partial loss of these fluids due to the evaporation of PFAS when exposed to high-temperature components. This high volatility and partial loss of PFAS necessitates their refilling into the heat exchange system, and at the same time, makes operators more susceptible to exposure to the fluid.

[0010] At the same time, concerns related to the environmental impact of PFAS have also been raised, making the use of PFAS particularly serious and requiring the adoption of complex and expensive containment systems to avoid any diffusion and / or contact with the external environment during operation, transport, and maintenance of systems and equipment using PFAS.

[0011] Therefore, the object of the present invention is to provide a novel thermal conductive fluid that can meet the performance requirements for the manufacture of semiconductor components while overcoming the environmental limitations of thermal conductive fluids currently in use, and the applicant has surprisingly found that thermal conductive fluids based on certain types of aliphatic diesters can be effectively used for such purposes. [Means for solving the problem]

[0012] In particular, the first embodiment relates to the use of a thermal conductive fluid comprising at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid for heat exchange with such semiconductor components in at least one manufacturing step of such semiconductor components.

[0013] Surprisingly, the applicant has found that such diesters exhibit appropriate rheological and hydrodynamic properties, thermal and chemical stability, and heat capacity properties, thereby making them effectively suitable for heat exchange with such semiconductor components during their manufacturing operations, and thus ensuring that these operations are carried out at optimal temperatures, minimizing thermal fluctuations that could lead to defects in microelectronic structures.

[0014] Advantageously, the diester can also provide a more environmentally sustainable solution for PFAS-based specialty fluids, reducing the complexity of operation, transport, and maintenance of cooling systems.

[0015] In a further embodiment, the present invention also relates to a method for manufacturing a semiconductor component, the method comprising at least one step of exchanging heat between the semiconductor component and a thermal conductive fluid, the thermal conductive fluid comprising a diester as defined in a first embodiment of the present invention. [Effects of the Invention]

[0016] The advantages of the method according to this aspect of the present invention have already been disclosed in relation to the use according to the first aspect of the present invention and will not be repeated here. [Modes for carrying out the invention]

[0017] In a first aspect, the present invention relates to the use of a thermal conductive fluid comprising at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid in at least one manufacturing process of a semiconductor component. The thermal conductive fluid is suitable for exchanging heat with such a semiconductor component, thereby ensuring that the manufacturing process is carried out at an optimal temperature and minimizing thermal fluctuations that could result in defects in the microelectronic structure of the semiconductor component.

[0018] Surprisingly, the applicant has found that such diesters exhibit suitable rheological and hydrodynamic properties, thermal and chemical stability, and heat capacity properties, which make them effectively suitable for heat exchange with such semiconductor components during the manufacturing process of semiconductor components, thus ensuring that these operations occur at optimal temperatures and minimizing thermal fluctuations that could result in defects in microelectronic structures.

[0019] Advantageously, the diester can also provide a more environmentally sustainable solution for PFAS-based specialty fluids and reduce the complexity of operation, transport, and maintenance of cooling systems.

[0020] In particular, the diesters offer an excellent alternative to PFAS-based fluids due to their remarkably low dynamic viscosity, especially at cryogenic temperatures. This superior property enables efficient pumping and circulation of heat-conducting fluids, even in the most extreme cold environments. Furthermore, these esters benefit from a high flash point and low volatility, ensuring both the safety and effective cooling of electronic equipment at high temperatures. Their unique combination of low viscosity, high flash point, and low volatility makes these diesters an ideal choice for various types of cooling systems for semiconductor-based components, providing efficient thermal management of their manufacture by offering reliable and efficient heat transfer capabilities while prioritizing safety and performance.

[0021] These fluids, due to their low viscosity, facilitate the effective conduction of heat from semiconductor components during their manufacture. The high flash points and low volatility of these esters ensure safe operation while minimizing the risk of fire or malfunction during such operations.

[0022] For example, such diesters can be used as the fluid that functions in a heat pipe, narrow flow channels or conduits that are widely used for indirect cooling during the manufacture of semiconductor components. These diesters enable efficient heat conduction under such conditions, allowing heat to be absorbed from the heat source and dissipated at the sink. The low viscosity of the fluid at the operating temperature ensures optimal circulation through the narrow flow channels or conduits, thus improving the overall cooling performance even when the contact time and heat conduction surface area are limited.

[0023] Therefore, in a cooling system with a closed loop commonly used in semiconductor cooling operations, for example, such diesters can advantageously act as heat transfer fluids. Since these fluids have a low dynamic viscosity at the operating temperature, they can easily flow through narrow flow channels and intricate cooling structures and efficiently carry away heat from the semiconductor components. The high flash point and low volatility enhance the safety and reliability of the cooling system.

[0024] The diesters can also be effectively used in a cold plate cooling system, in which case these diesters can advantageously flow through a metal plate that will come into direct contact with the semiconductor components. The low viscosity of these fluids enables efficient heat conduction from the metal plate and effective cooling of high-power electronic devices. The high flash point and low volatility of the ester ensure safe operation and minimize the risk of fluid leakage or system damage.

[0025] Within the scope of this specification and the subsequent claims, unless otherwise indicated, all numerical values representing amounts, parameters, percentages, etc. should be understood as being preceded by the term "about" in all cases. As used herein, the term "about" is understood by those skilled in the art and varies somewhat in the context in which it is used. As used herein, when referring to measurable values such as amounts, durations, etc., the term "about" means to encompass variations of ±20%, ±10%, for example ±5%, ±1%, and ±0.1% from a particular value, and such variations are appropriate for implementing the disclosed methods.

[0026] Also, all ranges of numerical values include all possible combinations of the maximum and minimum values, including all possible intermediate ranges in addition to the intermediate ranges specifically shown below in this specification.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] As used herein, the articles "a" and "an" refer to one or more than one (i.e., at least one) of the grammatical objects of the article. For example, "an element" means one element or more than one element.

[0029] The present invention may exist in one or more of the above aspects of one or more of the features disclosed below.

[0030] According to the present invention, the heat transfer fluid contains at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid.

[0031] Preferably, the C2-C9 aliphatic diol is selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, and mixtures thereof.

[0032] Preferably, the aliphatic diol of the diester according to the present invention is a C3-C6 aliphatic diol, and more preferably, is selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and mixtures thereof. Even more preferably, the aliphatic diol of the diester according to the present invention is a C3-C5 aliphatic diol selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, and mixtures thereof.

[0033] In a preferred embodiment, the aliphatic diol of the diester according to the present invention is selected from the group consisting of 1,2-propanediol, 1,3-propanediol, neopentyl glycol, and mixtures thereof, and is preferably selected from the group consisting of 1,2-propanediol, 1,3-propanediol, and mixtures thereof.

[0034] In one embodiment of the present invention, the linear or branched C2-C7 aliphatic monocarboxylic acid of the diester according to the present invention is a C3-C5 aliphatic monocarboxylic acid, more preferably selected from the group consisting of propanoic acid, butyric acid, isobutyric acid, 2-methylbutyric acid, 3-methylbutyric acid, valeric acid, and mixtures thereof, and more preferably selected from the group consisting of 2-methylbutyric acid, 3-methylbutyric acid, valeric acid, and mixtures thereof.

[0035] In another embodiment of the present invention, the linear or branched C2-C7 aliphatic monocarboxylic acid of the diester according to the present invention is a C5-C7 aliphatic monocarboxylic acid, and preferably, in such an embodiment, at least one of the monocarboxylic acids of the diester according to the present invention is a C5 acid. More preferably, in such an embodiment, the aliphatic monocarboxylic acid of the diester according to the present invention is a C5 acid, optimally valeric acid.

[0036] In preferred embodiments of the present invention, the diester is selected from the group consisting of neopentyl glycol divalellarate, 1,2-propanediyl divalellarate, 1,3-propanediyl divalellarate, 2-methyl-1,3-propanediyl divalellarate, and mixtures thereof, and more preferably from the group consisting of 1,2-propanediyl divalellarate, 1,3-propanediyl divalellarate, and mixtures thereof.

[0037] The diols, monocarboxylic acids, and diesters defined above, remarkably, exhibit a combination of properties such as low dynamic viscosity at temperatures down to -55°C and high volume resistivity, combined with a flash point higher than 125°C. This makes them particularly suitable and operationally efficient in indirect electronic cooling systems over a wide temperature range of -55°C to 125°C, and therefore particularly efficient as components of thermal conductive fluids for use in the manufacture of semiconductor components.

[0038] In addition to diesters, the thermal conductive fluid according to the present invention may advantageously contain one or more other components, such as synthetic or natural esters, mineral oil, polyethers such as polyalkylene glycols, polyolefins, and additives.

[0039] In one embodiment, the heat-conducting fluid according to the present invention is at least one diester as defined above, and at least one C6-C 12 Aliphatic monoalcohols, and at least one linear or branched C2-C2 chain. 12 It includes at least one monoester with an aliphatic monocarboxylic acid, such as monoesters like 2-propylheptanylvalerate and 2-ethylhexanylheptanoate.

[0040] Preferably, the heat-conducting fluid according to the present invention comprises at least one additive selected from the group consisting of antioxidants, pour point depressants, defoamers, corrosion inhibitors, viscosity modifiers, wear inhibitors and / or extreme pressure agents, friction modifiers, cleaning agents, dispersants, and mixtures thereof.

[0041] Advantageously, the heat-conducting fluid according to the present invention exhibits one or more of the following characteristics: Kinematic viscosity less than 50 mPa·s at -30°C; Flash point of 125°C or higher; Volume resistivity at 25°C higher than 0.1 teraohm-centimeter (TΩ·cm).

[0042] Furthermore, the thermal conductive fluid according to the present invention exhibits a heat capacity and thermal conductivity characteristics suitable for cooling semiconductor components during the manufacturing of semiconductor components.

[0043] Preferably, the heat-conducting fluid according to the present invention is in a liquid state when used in the manufacture of semiconductor components.

[0044] In the manufacturing of semiconductor components, the thermal conductive fluid according to the present invention may be used in a direct liquid cooling system or an indirect liquid cooling system.

[0045] As used herein, the expression “indirect liquid cooling system” means a cooling system in which the heat conduction fluid is in a liquid state or primarily in a liquid state during the operation of the system, and which is suitable for cooling the components to be cooled, but does not come into direct contact with these components. In particular, when referring to electronic components, an indirect liquid cooling system is a cooling system in which the heat conduction fluid does not come into direct contact with such electronic components, for example, by the interposition of different elements made of a thermally conductive material such as copper or other metals that are thermally coupled to the electronic components and interposed between the electronic components and the heat conduction fluid. These thermally conductive elements have the function of preventing direct contact between the fluid and the electronic components and conducting heat. In an indirect cooling system, such different elements interposed between the electronic components and the heat conduction fluid may have different shapes and configurations (heat sinks, walls inside tubes, or plates) depending on the design of the system.

[0046] In indirect cooling by heat conduction, a fluid exchanges heat with a thermally bonded material containing the component to be cooled. Both conduction and convection are involved, as the heat exchange is primarily influenced by the temperature difference between the component and the heat-conducting fluid. Another well-known factor influencing heat exchange is the amount of heat-exchange fluid used, which is limited by the design of the cooling system.

[0047] In a preferred embodiment, the thermal conductive fluid according to the present invention is used in an indirect cooling system in at least one step of the manufacturing process of a semiconductor component.

[0048] According to the present invention, the indirect liquid cooling system is not particularly limited and may be any type of indirect liquid cooling system known to those skilled in the art for indirectly cooling semiconductor components during their manufacture.

[0049] Preferably, the indirect liquid cooling system according to the present invention comprises at least one thermally conductive element thermally coupled to the semiconductor component, wherein the thermally conductive element is suitable for conducting heat from the semiconductor component to the thermally conductive fluid. More preferably, the thermally conductive element is selected from the group consisting of walls, layers, heat sinks, cold plates, heat pipes, and steam chambers.

[0050] Preferably, the indirect liquid cooling system includes: A liquid cooling loop suitable for circulating the heat-conducting fluid and A pump suitable for supplying the heat-conducting fluid throughout the liquid cooling loop, A heat exchanger suitable for cooling the aforementioned heat-conducting fluid, Optionally, a container suitable for containing the heat-conducting fluid.

[0051] According to the present invention, the semiconductor component may be of any type, and is preferably selected from the group consisting of a microprocessor, a semiconductor wafer, a power control semiconductor, and a semiconductor integrated circuit.

[0052] The thermal conductive fluid according to the present invention can be effectively used in any manufacturing process of semiconductor components thanks to the combination of its properties.

[0053] The aforementioned process may be any process known to those skilled in the art in the relevant field.

[0054] Preferably, the manufacturing process is selected from the group consisting of wafer manufacturing, polishing, oxidation, photoresist coating, photolithography, etching, preferably dry etching, deposition, ion implantation, annealing, metal wiring, and inspection.

[0055] Accordingly, in a further embodiment, the present invention also relates to a method for manufacturing a semiconductor component, the method comprising at least one step of exchanging heat between the semiconductor component and a thermal conductive fluid, the thermal conductive fluid comprising at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid, as defined in the first embodiment of the present invention.

[0056] The advantages and preferred features of this method have already been defined above with respect to a first aspect of the present invention and will therefore not be repeated here.

[0057] The method according to this aspect of the present invention uses a heat-conducting fluid as defined in the first aspect of the present invention. Therefore, the preferred characteristics of this heat-conducting fluid have already been defined above with respect to the same components in the first aspect of the present invention, and are therefore not repeated here.

[0058] The preferred features of the manufacturing process for the cooling system, semiconductor component, and method according to the present invention have already been defined above with respect to the same respective components in the first aspect of the present invention, and will not be repeated here.

[0059] Further features and advantages of the present invention should become clearer from the following description of some preferred embodiments, which are made below by the following non-limiting embodiments. [Examples]

[0060] <Example 1 - Preparation of neopentyl glycol dibarellat> 400 g (3.84 mol) of neopentyl glycol was placed in a multi-neck reaction flask equipped with an anchor stirrer, a Vigreux column, a condenser, and a distillation vessel. 980 g (9.6 mol) of valeric acid and 3 g of sodium hypophosphite monohydrate were added to the flask. Stirring was started, the system was purged with nitrogen, and the temperature was raised to the boiling point of the reaction mixture. The reaction was then continued until an amount of water equivalent to 100% of the stoichiometric amount for a 100% esterification yield had evaporated. Unreacted valeric acid was then removed by vacuum distillation until an acid value of less than 5 mg KOH / g was obtained. A stoichiometric excess of 4 wt% aqueous sodium hydroxide solution, sufficient to neutralize the acid value, was added to the esterification product, and the mixture was stirred for 30 minutes. The organic phase was then separated from the aqueous phase, washed with water, dried under vacuum, and filtered.

[0061] <Example 2-1,2 - Preparation of propanediyl divalerato> Example 1 was repeated using 292.18 g (3.84 mol) of 1,2-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0062] <Example 3-1,3-Preparation of propanediyl divalerato> Example 1 was repeated using 292.18 g (3.84 mol) of 1,3-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0063] <Example 4 - Preparation of 2-methyl-1,3-propanediyl divalerate> Example 1 was repeated using 346 g (3.84 mol) of 2-methyl-1,3-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0064] <Example 5 - Characterization of Diesters> The diesters obtained according to Examples 1-4 were characterized with respect to dynamic viscosity at -30°C in accordance with ISO 3219, flash point in accordance with ASTM D7094-04, pour point in accordance with ASTM D5950, and volume resistivity at 25°C in accordance with ASTM D1169. The results are reported in Table 1 below.

[0065] [Table 1]

[0066] <Example 6 - Characterization of Diesters> The diesters obtained according to Examples 1 to 4 were characterized with respect to thermal conductivity, thermal diffusivity, and specific heat.

[0067] The analysis was performed using the transient hot-wire method in accordance with ASTM D7896-19. The testing device used was Thermtest THW-L2, and the thermal conductivity and thermal diffusivity were measured at 40°C. The specific heat was calculated as follows: Cp at 40°C = Thermal conductivity at 40°C / (Thermal diffusivity at 40°C × Density at 40°C)

[0068] The results are reported in Table 2 below.

[0069] [Table 2]

[0070] Based on a comprehensive characterization of the diesters of the above-described examples that have been developed and characterized, it is clear that these fluids exhibit properties that make them highly promising as alternative solutions to PFAS-based fluids. These diesters exhibit remarkable features such as low viscosity at ultra-low temperatures, ensuring efficient flow and circulation even in demanding cooling applications. In addition, their high flash points enhance safety measures and reduce the potential risk of fire.

[0071] Furthermore, these diesters exhibit excellent volume resistivity and dielectric constant, ensuring optimal electrical insulation properties. In addition, their exceptional thermal conductivity and thermal capacity enable efficient heat dissipation, contributing to improved performance and reliability of electronic systems. Considering these advantageous properties, these diesters are a highly preferred alternative to PFAS fluids in the field of electronic cooling applications.

[0072] In summary, these diesters offer a more sustainable and environmentally friendly alternative to PFAS fluids, particularly in terms of greenhouse gas emissions. Their superior properties, coupled with reduced environmental impact, make them a highly preferred alternative for cooling semiconductor components.

Claims

1. At least one type of C ２ -C ９ an aliphatic diol and at least one linear or branched carbon ２ -C ７ Use of a thermal conductive fluid comprising at least one diester with an aliphatic monocarboxylic acid in at least one manufacturing process of a semiconductor component.

2. In the heat-conducting fluid, the diester C ２ -C ９ The use according to claim 1, wherein the aliphatic diol is selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, and mixtures thereof.

3. In the aforementioned heat-conducting fluid, the aliphatic diol of the diester is C ３ -C ６ The use according to claim 1 or 2, wherein the material is an aliphatic diol.

4. In the heat transfer fluid, the aliphatic diol of the diester is C ３ -C ５ The use according to claim 3, wherein the aliphatic diol is an aliphatic diol.

5. In the aforementioned heat-conducting fluid, the monocarboxylic acid of the diester is C ３ -C ５ The use according to any one of claims 1 to 4, wherein the aliphatic monocarboxylic acid.

6. In the aforementioned heat-conducting fluid, the monocarboxylic acid of the diester is C ５ -C ７ The use according to any one of claims 1 to 4, wherein the aliphatic monocarboxylic acid.

7. The use according to any one of claims 1 to 6, wherein the diester in the heat-conducting fluid is selected from the group consisting of neopentyl glycol divalerate, 1,2-propanediyl divalerate, 1,3-propanediyl divalerate, 2-methyl-1,3-propanediyl divalerate, and mixtures thereof.

8. The use of the heat-conducting fluid according to any one of claims 1 to 7, wherein the heat-conducting fluid is used in an indirect cooling system.

9. The use of the indirect liquid cooling system according to claim 8 includes the following: A liquid cooling loop suitable for circulating the aforementioned heat-conducting fluid, A pump suitable for supplying the heat-conducting fluid throughout the liquid cooling loop, A heat exchanger suitable for cooling the aforementioned heat-conducting fluid, Optionally, a container suitable for containing the heat-conducting fluid.

10. The use according to any one of claims 1 to 9, wherein the semiconductor component is selected from the group consisting of a microprocessor, a semiconductor wafer, a power control semiconductor, and a semiconductor integrated circuit.

11. The use according to any one of claims 1 to 10, wherein the at least one manufacturing step of the semiconductor component is selected from the group consisting of wafer manufacturing, polishing, oxidation, photoresist coating, photolithography, etching, deposition, ion implantation, annealing, metal wiring, and inspection.

12. A method for manufacturing a semiconductor component, comprising at least one step of exchanging heat between the semiconductor component and a thermal conductive fluid, wherein the thermal conductive fluid is at least one type C ２ -C ９ Aliphatic diol and at least one linear or branched carbon ２ -C ７ A method comprising at least one diester with an aliphatic monocarboxylic acid.

13. The method according to claim 12, wherein the heat conducting fluid is the heat conducting fluid described in any one of claims 1 to 7.

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