High-purity octafluorocyclobutane

Abstract

This disclosure aims to provide a new high-purity octafluorocyclobutane. [Solution] High-purity octafluorocyclobutane.

Description

Technical Field

[0001] The present disclosure relates to high-purity octafluorocyclobutane.

Background Art

[0002] Patent Document 1 discloses a dry etching gas composed of tetrafluoroethylene with a purity of 99.999% by weight or more of tetrafluoroethylene.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to newly provide high-purity octafluorocyclobutane.

Means for Solving the Problems

[0005] In semiconductor applications, conventionally, octafluorocyclobutane (c-C4F8) with a purity of 5N (99.999%) has been used. c-C4F8 with a purity of 5N cannot ignore the influence of impurities in semiconductor applications, storage, etc.

[0006] The present disclosure includes the following high-purity octafluorocyclobutane.

[0007] Item 1. A composition containing octafluorocyclobutane, where the content of octafluorocyclobutane is 99.99999% by volume or more with respect to the total amount of the composition.

[0008] Item 2. Furthermore, (2) it contains an additional compound, The composition according to item 1, wherein the content of (2) the additional compound is 0.0001% by volume (1 ppm by volume) or less relative to the total amount of the composition.

[0009] Section 3. The composition according to item 1, wherein the (2) additional compound is at least one component selected from the group consisting of noble gases, inert gases, NH3, H2, hydrocarbons, O2, oxygen compounds, iodine compounds, HFCs (hydrofluorocarbons), and PFCs (perfluorocarbons).

[0010] Section 4. The additional compounds in (2) above are: A noble gas selected from the group consisting of He, Ne, Ar, Xe, and Kr; Hydrocarbons selected from the group consisting of CH4, C2H6, C3H8, C2H4, and C3H6; An oxygen compound selected from the group consisting of CO, CO2, (CF3)2C=O, CF3CFOCF2, and CF3OCF3; Iodine compounds selected from the group consisting of CF3I, CF3CF2I, (CF3)2CFI, and CF2=CFI; HFCs selected from the group consisting of CH2F2, CH3F, CHF3, CF3CHF2, CHF2CHF2, CF3CH2F, CHF2CH2F, CF3CH3, CH2FCH2F, CF2=CHF, CHF=CHF, CH2=CF2, CH2=CHF, CF3CH=CF2, CF3CH=CH2, and CH3CF=CH2, CF4, C2F6, C3F8, CF2=CFCF2CF3, CF3CF=CFCF3, C4F 10 PFC selected from the group consisting of CF2=CF2, CF2=CFCF=CF2, CF3CF=CFCF=CF2, and c-C5F8; N2 (inert gas); NH3; H2; O2; H2O; HF; and metallic components; The composition according to item 1, wherein the composition is at least one component selected from the group consisting of the following.

[0011] Section 5. The additional compound (2) is at least one component selected from the group consisting of N2, O2, H2, CH4, Ar, H2O, HF, metal components, CF2 = CFCF2CF3, CF3CF = CFCF3, and C4F 10 The composition according to item 1 above, which is at least one component selected from the group consisting of

[0012] Item 6. The composition according to any one of items 1 to 5 above, wherein the composition is a cleaning agent or a polymerization solvent used in integrated circuit manufacturing.

[0013] Item 7. A method for storing a composition containing octafluorocyclobutane, A method in which the content of octafluorocyclobutane is 99.99999% by volume or more with respect to the total amount of the composition.

[0014] Item 8. A method for suppressing a decrease in the purity of octafluorocyclobutane in a composition containing octafluorocyclobutane, A method in which the content of octafluorocyclobutane is 99.99999% by volume or more with respect to the total amount of the composition.

[0015] The composition containing high-purity octafluorocyclobutane (c-C4F8) of the present disclosure is a rectified product of high purity 7N (99.99999% by volume or more), has good storage stability, can be stored in a state where physical properties are stable, and can then be used well. According to the present disclosure, it is possible to provide high-purity (7N) c-C4F8 for various applications such as solvents (cleaning agents) and polymerization solvents in the field of semiconductor integrated circuits.

Effects of the Invention

[0016] The present disclosure can newly provide high-purity octafluorocyclobutane.

Modes for Carrying Out the Invention

[0017] In this specification, "contains" and "include" encompass all of the following: "contains," "consist essentially of," and "consist of." In this specification, when a numerical range is expressed as "A to B," it means "greater than or equal to A and less than or equal to B." In this specification, when parts, percentages, etc. are expressed, they mean parts by mass, parts by weight, mass%, or weight% (wt%).

[0018] [1] Octafluorocyclobutane (cC 4 F 8 ) composition containing With the rapid development of integrated circuit (IC) technology, advanced miniaturization and high integration are progressing, as seen in semiconductor devices such as ULSI (Ultra-Large Scale Integration). This increases the integration density of chips and raises the demands on the performance and precision of transistor devices. In integrated circuit manufacturing, as chip manufacturing technology advances to the nanometer scale, impurities in the materials used directly affect the uniformity and stability of the chip manufacturing technology, thus requiring higher purity requirements for the materials used.

[0019] Octafluorocyclobutane (c-C4F8) is a stable chemical with a low potential for greenhouse gas emissions and is commonly used in the semiconductor industry. c-C4F8 has a relatively low ratio of fluorine and carbon, and also plays a role as a protective gas in integrated circuit manufacturing. In integrated circuit manufacturing, impurities in the materials used lead to process fluctuations and a decrease in process uniformity. Therefore, in integrated circuit manufacturing, the use of higher purity c-C4F8 is required to achieve high-precision processes.

[0020] (1) Octafluorocyclobutane (cC 4 F 8 ) The c-C4F8-containing composition of this disclosure contains (1) octafluorocyclobutane (perfluorocyclobutane, c-C4F8) as a first component.

[0021] A composition containing c-C4F8 contains (1) c-C4F8 as the main component. In a composition containing c-C4F8, the content of (1) c-C4F8 relative to the total volume (gas volume) of the composition is 99.99999% by volume or more, and the purity is 7N. Even if impurities in a composition containing c-C4F8 are present in trace amounts, their effect on c-C4F8 is unpredictable. For example, it is preferable to keep the amount of difluoromethane, trifluoroethylene, hydrogen, carbon monoxide, etc. below a certain level to minimize the impact on the device.

[0022] In a composition containing c-C4F8, (1) the c-C4F8 content relative to the total amount of the composition is 99.99999% by volume or more, preferably, in order, 99.999995% by volume or more, 99.999999% by volume or more, 99.9999995% by volume or more, and 99.9999999% by volume or more.

[0023] To separate impurities from a composition containing c-C4F8, rectification is preferably employed as the separation method. To obtain a composition with a c-C4F8 content of 99.99999% by volume or more, c-C4F8 is preferably separated by a high-stage rectification column, and separation by a very high-stage rectification column is particularly preferred.

[0024] In a composition containing c-C4F8, by adjusting the concentration of c-C4F8 within the aforementioned range, the decomposition of c-C4F8 can be suppressed when transporting the c-C4F8-containing composition in cylinders or the like, the decrease in the purity of c-C4F8 in the c-C4F8-containing composition can be suppressed, and the storage stability of the c-C4F8-containing composition can be well maintained. The c-C4F8-containing composition can be transported stably even under harsh conditions during maritime transport in containers, etc. (such as temperature increases during transport), as the decomposition of c-C4F8 is suppressed.

[0025] (2) Additional compounds The c-C4F8-containing compositions of this disclosure preferably further contain (2) an additional compound as a second component. In the c-C4F8-containing composition, the content of (2) the additional compound is preferably 0.0001 volume% (1 volume ppm, ppm volume) or less relative to the total amount (gas volume) of the composition. If the additional compound is mixed (blended) with two or more additional compounds, the content of the additional compound is the total amount of the additional compounds. Even if the amount of impurities in the c-C4F8-containing composition is trace, the effect on c-C4F8 is unpredictable. For example, for CH2F2, CHF=CF2, H2, CO, etc., it is preferable to keep the amount below a predetermined level in order to minimize the impact on the device.

[0026] The additional compound is preferably at least one component selected from the group consisting of noble gases, inert gases, NH3, H2, hydrocarbons, O2, oxygen compounds, iodine compounds, HFCs (hydrofluorocarbons), and PFCs (perfluorocarbons).

[0027] The additional compound is preferably a noble gas selected from the group consisting of He, Ne, Ar, Xe, and Kr. Noble gases have a gas dilution effect.

[0028] The additional compound is preferably a hydrocarbon selected from the group consisting of CH4, C2H6, C3H8, C2H4, and C3H6.

[0029] The additional compound is preferably an oxygen compound selected from the group consisting of CO, CO2, (CF3)2C=O, CF3CFOCF2, and CF3OCF3.

[0030] The additional compound is preferably an iodine compound selected from the group consisting of CF3I, CF3CF2I, (CF3)2CFI, and CF2=CFI.

[0031] The additional compound is preferably an HFC selected from the group consisting of CH2F2, CH3F, CHF3, CF3CHF2, CHF2CHF2, CF3CH2F, CHF2CH2F, CF3CH3, CH2FCH2F, CF2=CHF, CHF=CHF, CH2=CF2, CH2=CHF, CF3CH=CF2, CF3CH=CH2, and CH3CF=CH2. The HFC allows for control of the balance between fluorocarbon radicals and fluorocarbon ions.

[0032] The additional compounds are preferably CF4, C2F6, C3F8, CF2=CFCF2CF3, CF3CF=CFCF3, and C4F 10 This PFC is selected from the group consisting of CF2=CF2, CF2=CFCF=CF2, CF3CF=CFCF=CF2, and c-C5F8.

[0033] The additional compound is preferably a component selected from N2 (inert gas); NH3, H2, O2; H2O; HF; and a metal component.

[0034] The composition containing c-C4F8 may contain one additional compound alone, or a mixture (blend) of two or more additional compounds.

[0035] The additional compounds are preferably N2, O2, H2, CH4, Ar, H2O, HF, metal components, CF2=CFCF2CF3, CF3CF=CFCF3, and C4F 10 It is at least one component selected from the group consisting of the following:

[0036] In a composition containing c-C4F8, the content of (2) the additional compound relative to the total amount of the composition is preferably 0.0001 volume% (1 volume ppm) or less, more preferably, in order, 0.00005 volume% (0.5 volume ppm) or less, 0.00001 volume% (0.1 volume ppm) or less, 0.000005 volume% (0.05 volume ppm) or less, and 0.000001 volume% (0.01 volume ppm) or less.

[0037] The problematic additional compounds (or impurities) in compositions containing c-C4F8 are hydrogen-containing compounds (such as CH2F2, CHF=CF2, etc.), H2, CO, etc. By adjusting the total amount of these additional compounds to 0.0001 volume% (1 volume ppm) or less, stable and good results can be obtained in the manufacture of increasingly miniaturized semiconductor devices.

[0038] The c-C4F8-containing composition of this disclosure has a c-C4F8 content of 99.99999% by volume or more and is of high purity 7N. By using the c-C4F8-containing composition of this disclosure, it is possible to stably produce miniaturized and highly integrated semiconductor devices with minimal adverse effects from impurities.

[0039] In a composition containing c-C4F8, by adjusting the concentration of the additional compound to the aforementioned range, the decomposition of c-C4F8 can be suppressed when transporting the c-C4F8-containing composition in cylinders or the like, the decrease in the purity of c-C4F8 in the c-C4F8-containing composition can be suppressed, and the storage stability of the c-C4F8-containing composition can be well maintained. The c-C4F8-containing composition can be transported stably even under harsh conditions during maritime transport in containers, etc. (such as temperature increases during transport), as the decomposition of c-C4F8 is suppressed.

[0040] [2] Octafluorocyclobutane (cC 4 F 8 Method for preserving a composition containing ) This disclosure comprises methods for storing compositions containing c-C4F8.

[0041] This disclosure includes a method for suppressing a decrease in the purity of c-C4F8 in a composition containing c-C4F8.

[0042] A description of compositions containing c-C4F8 is provided above. [1]cC 4 F 8 Composition containing Apply the explanation.

[0043] This disclosure provides a method for stably transporting a composition containing c-C4F8. According to this disclosure, by adjusting the concentration of c-C4F8 in a composition containing c-C4F8, it is possible to suppress the decomposition of c-C4F8 when transporting the composition in cylinders or the like, suppress the decrease in the purity of c-C4F8 in the composition, and maintain good storage stability of the composition containing c-C4F8.

[0044] The c-C4F8-containing composition of this disclosure contains c-C4F8, suppresses the generation of c-C4F8-derived decomposition products, and has improved storage stability. It can be transported stably even under harsh conditions in maritime transport such as containers (e.g., temperature rise during transport), as it suppresses the decomposition of c-C4F8.

[0045] [3] Octafluorocyclobutane (cC 4 F 8 In a composition containing cC 4 F 8 Method to suppress the decrease in purity The c-C4F8-containing compositions of this disclosure improve process stability in integrated circuit manufacturing, can be applied to advanced processes, and lead to improved device uniformity and yield.

[0046] Compositions containing c-C4F8 can be readily applied as cleaning agents or polymerization solvents used in the manufacture of integrated circuits.

[0047] This disclosure provides a method for stably transporting a composition containing c-C4F8. According to this disclosure, by including c-C4F8 in a composition containing high-purity 7N (99.99999% by volume or higher) refined c-C4F8, the decomposition of c-C4F8 can be suppressed when the composition is transported in cylinders or the like, the decrease in purity of c-C4F8 can be suppressed, and the storage stability of the c-C4F8-containing composition can be maintained.

[0048] The c-C4F8-containing composition of this disclosure contains high-purity 7N refined c-C4F8, has improved storage stability, and can be transported stably even under harsh conditions in maritime transport such as containers (e.g., temperature rise during transport), as it suppresses the decomposition of c-C4F8. [Examples]

[0049] The present invention will be described in detail below using examples and comparative examples. However, the present invention is not limited to these.

[0050] [1] Octafluorocyclobutane (cC 4 F 8 Storage stability of compositions containing ) Octafluorocyclobutane: c-C4F8 Additional compound: C4F 10 Purified c-C4F8 (high purity 7N, 99.99999% by volume or higher) and additional compound C4F 10 A composition containing c-C4F8 was prepared by adjusting the concentration to a predetermined level (0.0001% by mass (1 volume ppm) or less).

[0051] In a composition containing c-C4F8, the concentration of c-C4F8 (volume ppm) and the additional compound C4F8 10 The concentration (volume ppm) was analyzed by gas chromatography (GC analysis).

[0052] Compositions containing c-C4F8 were stored at a constant temperature (20°C and 50°C), and after a certain period of time (30 days, 90 days, and 180 days), the gas phase was extracted, and decomposition products derived from c-C4F8 were analyzed by GC (volume ppm).

[0053] The c-C4F8-containing composition of the example contains c-C4F8 in high purity 7N (99.99999% by volume or higher), with the additional compound C4F 10By adjusting the concentration to 0.0001% by mass (ppm per volume) or less, the generation of c-C4F8-derived decomposition products was effectively suppressed even after storage at a constant temperature (20°C and 50°C) and after a certain period of time (30 days, 90 days, and 180 days).

[0054] [2] Industrial applicability The c-C4F8-containing compositions of this disclosure improve process stability in integrated circuit manufacturing, can be applied to advanced processes, and lead to improved device uniformity and yield.

Claims

1. A composition containing octafluorocyclobutane, A composition in which the content of (1) octafluorocyclobutane is 99.99999% by volume or more, relative to the total amount of the composition.

2. Furthermore, (2) containing additional compounds, The composition according to claim 1, wherein the content of (2) the additional compound is 0.0001% by volume (1 ppm by volume) or less relative to the total amount of the composition.

3. The aforementioned (2) additional compounds are noble gases, inert gases, and NH4. 3 H 2 , hydrocarbons, O 2 The composition according to claim 1, wherein the composition is at least one component selected from the group consisting of oxygen compounds, iodine compounds, HFCs (hydrofluorocarbons), and PFCs (perfluorocarbons).

4. The additional compound in (2) above is A noble gas selected from the group consisting of He, Ne, Ar, Xe, and Kr; CH 4 、 C 2 H 6 、 C 3 H 8 、 C 2 H 4 、 and C 3 H 6 a hydrocarbon selected from the group consisting of; CO, CO 2 , (CF 3 ) 2 C=O, CF 3 CFOCF 2 , and CF 3 OCF 3 An oxygen compound selected from the group consisting of; CF 3 I, CF 3 CF 2 I, (CF 3 ) 2 CFI and CF 2 Iodine compounds selected from the group consisting of =CFI; CH 2 F 2 CH 3 F, CHF 3 , CF 3 CHF 2 CHF 2 CHF 2 , CF 3 CH 2 F, CHF 2 CH 2 F, CF 3 CH 3 CH 2 FCH 2 F, CF 2 =CHF, CHF=CHF, CH 2 =CF 2 CH 2 =CHF, CF 3 CH=CF 2 , CF 3 CH=CH 2 , and CH 3 CF=CH 2 HFCs selected from the group consisting of, CF 4 , C 2 F 6 , C 3 F 8 , CF 2 =CFCF 2 CF 3 , CF 3 CF = CFCF 3 , C 4 F 10 , CF 2 =CF 2 , CF 2 =CFCF=CF 2 , CF 3 CF=CFCF=CF 2 , and cC 5 F 8 PFC selected from the group consisting of; N 2 NH 3 ;H 2 ;O 2 ;H 2 O; HF; and metallic components; The composition according to claim 1, wherein the composition is at least one component selected from the group consisting of the following.

5. The additional compound in (2) above is N 2 , O 2 H 2 CH 4 , Ar, H 2 O, HF, metal components, CF 2 =CFCF 2 CF 3 , CF 3 CF = CFCF 3 , and C 4 F 10 The composition according to claim 1, wherein the composition is at least one component selected from the group consisting of the following.

6. The composition according to any one of claims 1 to 5, wherein the composition is a cleaning agent or polymerization solvent used in the manufacture of integrated circuits.

7. A method for preserving a composition containing octafluorocyclobutane, A method comprising (1) ensuring that the content of octafluorocyclobutane is 99.99999% by volume or more relative to the total amount of the composition.

8. A method for suppressing the decrease in purity of octafluorocyclobutane in a composition containing octafluorocyclobutane, A method comprising (1) ensuring that the content of octafluorocyclobutane is 99.99999% by volume or more relative to the total amount of the composition.