Hydrofluoroether compositions

Abstract

A hydrofluoroether composition is provided that can suppress the formation of acid components even at high temperatures (e.g., above 90°C). A hydrofluoroether composition comprising 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene, wherein the content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is 0.0001% by mass or more and less than 2.0000% by mass.

Description

Technical Field

[0001] This invention relates to hydrofluoroether (HFE) compositions that are useful as heat transfer media, etc. Background Technology

[0002] Heat transfer media are used in various heat transfer methods, such as temperature control of wafers in semiconductor manufacturing, cooling and heating of semiconductor components and electronic parts, cooling of servers, heat pumps, heat pipes, and temperature control of thermostatic baths.

[0003] Perfluorocarbons (PFCs) have been widely used as heat transfer media in the past. However, PFCs have the problem of high global greenhouse effect (GWP) and significant environmental impact due to the greenhouse effect.

[0004] Therefore, HFE, which has a smaller environmental impact, is being investigated as an alternative heat transfer medium to PFC (e.g., see Patent Document 1).

[0005] However, HFE has lower thermal stability than PFC. When used continuously as a heat medium, it may produce acidic components such as hydrogen fluoride due to decomposition and detachment, which may lead to corrosion, deterioration, or even failure of heat medium circulation devices.

[0006] As a means of suppressing the decomposition of fluorinated thermal media, known methods include adding known stabilizers such as phenolic compounds, aromatic compounds containing unsaturated hydrocarbon groups, aromatic amine compounds, aromatic thiazide compounds, terpenoid compounds, quinone compounds, nitro compounds, epoxy compounds, orthoester compounds, etc. (for example, see Patent Document 2).

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Publication No. 2007-524737

[0010] Patent Document 2: International Publication No. 2016 / 181910 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, in dry etching processes using thermal plasma in semiconductor manufacturing, for example, when using a thermal medium containing known stabilizers in an HFE under harsh conditions of high electric field and high temperature (e.g., above 90°C), sometimes a portion of the thermal medium decomposes, failing to adequately exhibit the required properties (e.g., high insulation).

[0013] Therefore, for heat transfer media using HFE, it is required that the generation of acid components from the heat transfer media over time be suppressed without the use of large amounts of the previous stabilizers, so that it can be used stably and continuously as a heat transfer media.

[0014] The present invention was made in view of this situation, and its object is to provide an HFE composition that can suppress the formation of acid components even at high temperatures, such as above 90°C.

[0015] Solution for solving the problem

[0016] This invention is based on the discovery that by combining a specified HFE with a specified compound, the formation of acid components can be suppressed even after several days at high temperatures, such as above 90°C.

[0017] The present invention provides the following means.

[0018] [1] A hydrofluoroether composition comprising 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene, wherein the content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is 0.0001% by mass or more and less than 2.0000% by mass.

[0019] [2] The hydrofluoroether composition according to [1] wherein the content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is 0.0001% by mass or more and 1.0000% by mass or less.

[0020] [3] A heat medium, which is a hydrofluoroether composition of [1] or [2].

[0021] [4] The heat medium described in [3] is used for cooling or heating of constituent components in a semiconductor manufacturing apparatus.

[0022] The effects of the invention

[0023] The HFE composition of the present invention can suppress the formation of acid components even at high temperatures, such as above 90°C. Therefore, the HFE composition of the present invention can be used stably and continuously as a heat medium. Detailed Implementation

[0024] The HFE composition of the embodiments of the present invention (hereinafter also referred to as this embodiment) comprises 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (hereinafter referred to as HFE-77-12) and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene, wherein the content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is 0.0001% by mass or more and less than 2.0000% by mass.

[0025] HFE-77-12 is an HFE compound with the chemical formula CF3CHFCF2OCH2CH2OCF2CHFCF3. HFE-77-12 has a high boiling point of 164°C and a freezing point of less than -100°C, making it a liquid over a wide temperature range and thus suitable for use as an excellent heat transfer medium.

[0026] 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene, represented by the chemical formula CF3CF=CFOCH2CH2OCF2CHFCF3, is a compound having a structure in which hydrogen fluoride is removed from a fluoroalkyl group bonded to one ether oxygen atom of HFE-77-12 (hereinafter referred to as the de-HF form).

[0027] The HFE composition of this embodiment, which contains HFE-77-12 and trace amounts of the deHF-containing body at a mass percentage of 0.0001% or more and less than 2.0000% (1 ppm or more and less than 20000 ppm), can suppress the formation of acid components even after several days at high temperatures of 90°C or higher, and further at 150°C.

[0028] The reason for the inhibition of acid formation is unclear, but it is speculated that even when HFE-77-12 decomposes at high temperatures to produce acidic components such as hydrogen fluoride, trace amounts of the deHF-containing emulsion in the HFE composition will capture these acidic components. If hydrogen fluoride adds to the deHF-containing emulsion, it becomes HFE-77-12. Therefore, it is believed that even if the deHF-containing emulsion captures the acidic components, it will not produce products with significantly different structures that would drastically alter the properties of the HFE composition as a heat transfer medium, and can therefore act as a stabilizer for HFE-77-12.

[0029] Therefore, when the HFE composition of this embodiment is used as a heat medium, it can suppress corrosion of metal components of the heat medium circulation device caused by acid components originating from HFE.

[0030] From the viewpoint of effectively suppressing the formation of acid components in the HFE composition, the content of the deHF-containing component in the HFE composition of this embodiment is 0.0001% by mass or more and less than 2.0000% by mass (1 ppm by mass or more and less than 20000 ppm by mass), preferably 0.0001% by mass or more and less than 1.0000% by mass (1 ppm by mass or more and less than 10000 ppm by mass), and more preferably 0.0010% by mass or more and less than 0.1000% by mass (10 ppm by mass or more and less than 1000 ppm by mass).

[0031] By ensuring the content of the deHF-containing emulsion is 1 ppm or more by mass, the formation of acidic components in the HFE composition can be effectively suppressed. However, if the content of the deHF-containing emulsion is too high, it may hinder the properties of HFE-77-12 itself as a heat transfer medium, and therefore is not preferred. Specifically, if the content of the deHF-containing emulsion is 2.0000% by mass or more, the formation of acidic components in the HFE composition cannot be sufficiently suppressed. The reason for this is not yet clear, but it is believed that if there is too much deHF-containing emulsion, it may exceed the acid-capturing capacity, leading to the formation of acidic components due to the decomposition of the deHF-containing emulsion itself.

[0032] The content of HFE-77-12 in the HFE composition of this embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0033] When the HFE composition of this embodiment is used as a heat medium, from the viewpoint of maximizing the good properties of HFE-77-12 itself as a heat medium, the content of HFE-77-12 in the HFE composition of this embodiment is preferably more than 98.0000% by mass and less than 99.9999% by mass, more preferably more than 99.0000% by mass and less than 99.9990% by mass, and even more preferably more than 99.9000% by mass and less than 99.9990% by mass.

[0034] When the HFE composition of this embodiment is used as a heat medium, from the viewpoint of stably exerting the characteristics of HFE-77-12 as a heat medium, the total content of HFE-77-12 and the de-HF agent is preferably 99.0000% by mass or more, more preferably 99.5000% by mass or more, and particularly preferably 100% by mass.

[0035] The HFE composition of this embodiment may consist only of HFE-77-12 and the deHF remover. However, without impairing the effects of the present invention, it may also contain components other than HFE-77-12 and the deHF remover (e.g., fluorinated solvents) for various purposes such as improving various properties.

[0036] The HFE composition of this embodiment preferably contains less than 70% by mass, more preferably less than 50% by mass, even more preferably less than 30% by mass, and even more preferably less than 20% by mass.

[0037] As a fluorinated solvent, examples include Galden (registered trademark) HT90 / 110 / 135 / 150 / 170 / 200 (and above, CF3-[OCF(CF3)(CF2)]) manufactured by Solvay. n (OCF2) m [-CF3), ZV90, SVX, ZT-180; FTM-110 / 135 / 150 / 170 / 200 / 230 / 270 manufactured by Sanming Hexafluo Chemicals; Fluorinert (registered trademark) FC-75(C8F8) / 3283((C3F7)3N) / 40((C4F9)3N) / 43((C4F9)3N) / 70((C5F) 11 )3N), FX-3300 (C8F8), Novec 7100 (a mixture of CF3(CF2)3OCH3 and (CF3)2CFCF2OCH3) / 7200 (a mixture of CF3(CF2)3OC2H5 and (CF3)2CFCF2OC2H5) / 7300 ((CF3)2CFCF(CF2CF3)OCH3) / 7500 (CF3CF2CF2CF(OCH2CH3)CF(CF3)CF3) / 7600 (CF3CFHCF2OC(CH3)CF2CFHCF3); Chemours Opteon (registered trademark) SF10 / 30 (a mixture of CF3CH=CHCF3 and CClH=CClH) / 33 (CF3CH=CHCF3) / 2P50 manufactured by AGC; ASAHIKLIN (registered trademark) AC-2000 (CF3CF2CF2CF2CF2CF2H) / 6000 (CF3CF2CF2CF2CF2CF2CH2CH3) and AMOLEA (registered trademark) AS-300 (CF2HCF=CClH) manufactured by AGC; Cerefin (registered trademark) 1233Z (HCFO-1233zd(Z)) / CGS-5E manufactured by Central Glass Co., Ltd.; DAISAVE (registered trademark) SS-54 manufactured by DAIKIN INDUSTRIES, LTD.; and HFE-65-12 manufactured by Zhongjuxin Company, etc., are commercially available products.

[0038] The HFE composition of this embodiment is obtained by mixing HFE-77-12 and the deHF derivative. The manufacturing methods of HFE-77-12 and the deHF derivative are not particularly limited.

[0039] HFE-77-12 can be synthesized, for example, by known methods such as the addition reaction of hexafluoropropylene with ethylene glycol in the presence of a basic catalyst such as potassium carbonate.

[0040] The HF-dehydrogenated form can be synthesized, for example, by reacting HFE-77-12 in the presence of a strong base such as an alkali metal alkoxide to remove hydrogen fluoride.

[0041] Specifically, HFE-77-12 and the HF remover can be manufactured by the methods described in the following examples.

[0042] The HFE composition of this embodiment has a small GWP, so it can be used in a wide range of applications, such as cleaning agents, solvents, foaming agents, aerosols, heat pipes, working media for binary power generation for factory waste heat recovery, preservation fluids for electronic components, media for rough leak detection of electronic components, thermal shock testing, liquid aging testing, and withstand voltage testing.

[0043] In addition, as mentioned above, it can suppress the formation of acid components even at high temperatures above 90°C, thus making it suitable for use as a heat transfer medium.

[0044] Examples of heat transfer media include temperature control of wafers in semiconductor manufacturing, cooling and heating of semiconductor components and electronic parts, cooling of servers, heat pumps, heat pipes, thermostatic baths, etc.

[0045] The HFE composition of this embodiment is suitable as a heat medium for cooling or heating constituent components in a semiconductor manufacturing apparatus. For example, it is also suitable as a heat medium for continuous use under harsh conditions of high electric field and high temperature environment, such as dry etching processes using thermal plasma in semiconductor manufacturing.

[0046] Furthermore, as described above, the HFE composition of this embodiment can also be suitably used as a cleaning agent. Specifically, it can also be used to remove contaminants (reaction products such as silicon oxide generated during the etching process) deposited in the chambers of dry etching apparatus used in semiconductor manufacturing.

[0047] Example

[0048] The present invention will now be described in detail based on embodiments, but the present invention is not limited to the following embodiments.

[0049] The reaction products were identified by proton nuclear magnetic resonance (NMR). 1 ¹H NMR spectroscopy, fluorine-19 NMR ( 19The analysis was performed using F NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS using a column: "DB-1301", 60m in length, 250μm in inner diameter, 1μm in thickness; manufactured by Agilent Technologies Japan, Ltd.).

[0050] [Synthesis of HFE-77-12]

[0051] In a 2.1-liter stainless steel autoclave equipped with a stirrer, add 223g of potassium carbonate (manufactured by Junsei Chemicals Co., Ltd.), 200g of ethylene glycol (manufactured by Junsei Chemicals Co., Ltd.), and 400g of anhydrous acetonitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation). Maintain the autoclave at 20°C under a sealed environment. Stir the contents of the autoclave and add 966g of hexafluoropropylene (manufactured by AGC Corporation) in a gaseous state over 6 hours. After maintaining the reaction at 20°C for 1 hour, filter and recover the crude reaction product from the autoclave.

[0052] The recovered crude reaction solution contained 45% by mass of HFE-77-12 and 4.5% by mass of deHF derivative.

[0053] Next, 1000 g of the crude reaction solution and 100 g of anhydrous hydrogen fluoride (manufactured by AGC Corporation) were added to a Hastelloy (registered trademark) autoclave (internal volume 2.1 liters), and the mixture was stirred for 1 hour. The resulting crude reaction solution was separated into phases, washed with water, dried using molecular sieve 3A (manufactured by FUJIFILM Wako Pure Chemical Corporation), and then purified by distillation to obtain HFE-77-12.

[0054] [Synthesis of deHF derivatives]

[0055] 117 g of tert-butanol (manufactured by Kanto Chemical Co., Ltd.) and 75 g of HFE-77-12 were added to a glass reactor (0.5 L) equipped with a stirrer. The mixture was heated to 40 °C while stirring, and 100 g of potassium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was added intermittently over 5 hours. After maintaining the reaction at 40 °C for 2 hours, the crude reaction solution was neutralized with a 10% (w / w) potassium bicarbonate aqueous solution and washed with water. The organic layer was recovered and purified by distillation to obtain the de-HF phase.

[0056] [Examples 1-6] Preparation of HFE compositions

[0057] The synthesized HFE-77-12 and the deHF-removed form were mixed in the proportions shown in Table 1 to prepare compositions 1 to 6.

[0058] [High-Temperature Stability Test]

[0059] The HFE compositions (compositions 1 to 6) of Examples 1 to 6 were evaluated by the following high-temperature stability tests.

[0060] 100g of the HFE composition was immersed in a polytetrafluoroethylene (PTFE) container containing a test piece (25mm × 30mm, 2mm thick) of general-purpose cold-rolled steel sheet (SPCC) and stored at 100°C or 150°C for 7 days. The appearance of the test piece after the test was visually observed, and the results of evaluating the high-temperature stability (presence or absence of acidic components) of the HFE composition according to the following evaluation criteria are shown in Table 1.

[0061] <Evaluation Criteria>

[0062] A: No change

[0063] B: The surface gloss disappears.

[0064] C: Part of the surface is rusty

[0065] D: Overall rust on the surface

[0066] In evaluations of cases A and B, no rust was observed on the test pieces, which was considered an inhibition of the formation of acid components from the HFE composition. In evaluations of cases C and D, rust was observed on the test pieces, which was considered an indication that the HFE composition generated acid components at high temperatures.

[0067] [Table 1]

[0068]

[0069] Based on the results shown in Table 1, in the case where the HFE composition does not contain the deHF agent and HFE-77-12 is 100% by mass (Example 1), it is speculated that acid components are easily generated at high temperatures above 100°C. HFE compositions (Examples 2-5) with the content of the deHF agent being 0.0001% by mass or more and less than 2.0000% by mass (1 ppm by mass or more and less than 20000 ppm by mass) suppress the generation of acid components containing hydrogen fluoride through the acid component capture effect of the deHF agent.

[0070] When the content of the deHF-containing material in the HFE composition is 2.0000% by mass (Example 6), it is speculated that at a high temperature of 150°C, the deHF-containing material undergoes thermal decomposition, exceeding the capture capacity of the acid component, thereby generating an acid component in the HFE composition.

[0071] It should be noted that it has been confirmed that in a semiconductor manufacturing apparatus equipped with a mechanism for circulating a heat medium to transfer heat, even when the HFE composition of Example 4 is used as a heat medium and circulated at a controlled temperature of 100°C for 100 hours, it can be used without any problems.

Claims

1. A hydrofluoroether composition comprising 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene, The content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is greater than 0.0001% by mass and less than 2.0000% by mass.

2. The hydrofluoroether composition according to claim 1, wherein, The content of 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene is greater than 0.0001% by mass and less than 1.0000% by mass.

3. A heat medium, which is the hydrofluoroether composition according to claim 1 or 2.

4. The heat transfer medium according to claim 3, used for cooling or heating constituent components in a semiconductor manufacturing apparatus.

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