METHOD OF MANUFACTURING SEMICONDUCTOR DEVICES USING A HEAT TRANSFER FLUID COMPRISING FLUORINATED COMPOUNDS HAVING A LOW GWP

Abstract

The present invention relates to a method for manufacturing semiconductor devices, including a step wherein a semi-conductor device exchanges heat with a heat transfer fluid. The heat transfer fluid comprises one or more chemical compounds having the general formula: Ph(OR.sub.f).sub.x (I) wherein Ph is an aromatic ring linked to one or more ether groups —OR.sub.f where each —R.sub.f: — is a monovalent fluorinated alkyl group comprising at least one C—F bond, — has a carbon chain, preferably a C.sub.1-C.sub.10 carbon chain, which can be linear or can comprise branches and/or cycles, and, optionally, can comprise in chain heteroatoms selected from O, N or S, and wherein, when X>1, the —R.sup.f groups on the same molecule can be equal to or different from each other.

Claims

1-12. (canceled)

13. A method for manufacturing semiconductor devices, said method including a step wherein a semiconductor device exchanges heat with a heat transfer fluid, said heat transfer fluid comprising one or more chemical compounds having the general formula:
a. Ph(OR.sub.f).sub.x   (I) wherein Ph is an aromatic ring linked to one or more ether groups —OR.sub.f where each —R.sub.f: is a monovalent fluorinated alkyl group comprising at least one C—F bond, has a carbon chain which is linear or comprise branches and/or cycles, and, optionally, comprises in chain heteroatoms selected from O, N or S, and wherein, when X>1, the —R.sub.f groups on the same molecule can be equal to or different from each other.

14. A method according to claim 13 said method comprising using one or more of a semiconductor processing equipment selected from an Etcher, an Asher, a Stepper and a plasma enhanced chemical vapour deposition (PECVD) chamber, said semiconductor processing equipment including at least one temperature control unit (TCU) exchanging heat with said semiconductor device, wherein said TCU comprises said heat transfer fluid.

15. A method according to claim 13 which is a method for thermal shock testing of semiconductor devices, said method comprising, in any order: i. cooling said semiconductor device to a temperature comprised from −10° C. and −100° C. using a first bath being made of said heat transfer fluid and ii. heating said semiconductor to a temperature from 60° C. and 250° , using a second bath being made of said heat transfer fluid.

16. A method according to claim 13 which is a method for vapor phase soldering of semiconductor devices, said method including i. providing a semiconductor device comprising soldering paste, ii. providing a closed chamber comprising said heat transfer fluid at its boiling point so that heated vapors of said heat transfer fluid are generated within said closed chamber iii. introducing said semiconductor device in said closed chamber, in contact with said vapors of said heat transfer fluid thereby melting said soldering paste by contact with said heated vapors.

17. A method according to claim 13 wherein, in said chemical compound having general formula (I), x is selected from 1, 2, 3 and 4.

18. A method according to claim 13 wherein, in said chemical compound having general formula (I), multiple R.sub.f groups on the same molecule are equal to each other.

19. A method according to claim 13 wherein, in said chemical compound having general formula (I), each R.sub.f group comprises at least one C—H bond.

20. A method according to claim 13 wherein, in said chemical compound having general formula (I), each R.sub.f group has exactly one C—H bond.

21. A method according to claim 20 wherein, in said chemical compound having general formula (I), each R.sub.f group has exactly one C—H bond on the carbon atom in position 2.

22. A method according to claim 13 wherein said one or more chemical compounds of general formula (I) make up at least 5% by weight of said heat transfer fluid.

23. A method according to claim 13 wherein said compound is selected from 1,4-bis(1,1,2,2-tetrafluoroethoxy)benzene, 1,4-bis(2-trifluoromethyl-1,1,2-trifluoroethoxy)benzene, 1,3-bis(1,1,2,2-tetrafluoroethoxy)benzene, 1,3-bis(2-trifluoromethyl-1,1,2-trifluoroethoxy)benzene, 1,2-bis(1,1,2,2-tetrafluoroethoxy)benzene, 1,2-bis(2-trifluoromethyl-1,1,2-trifluoroethoxy)benzene, 1,2-bis(2-trifluoromethoxy-1,1,2-trifluoroethoxy)benzene, 1,3-bis(2-trifluoromethoxy-1,1,2-trifluoroethoxy)benzene, 1,4-bis(2-trifluoromethoxy-1,1,2-trifluoroethoxy)benzene and mixtures thereof.

24. A method according to claim 13 wherein said heat transfer fluid has a GWP100 of less than 30.

Description

EXAMPLES

[0093] Synthesis of 1,4-Bis(1,1,2,2-tetrafluoroethoxy)benzene (HFE 1,4): In a 600 mL steel autoclave were loaded 60.0 g of hydroquinone, with 16 g of KOH and 360 mL of acetonitrile. The autoclave was purged four times with nitrogen and drawn to moderate vacuum (0.2bar).

[0094] The mixture was stirred vigorously for 30 minutes at 70° C., then tetrafluoroethylene was introduced gradually up to 10 bar in 6 hours. The reactor was left stirring for a total of 20 h, then it was cooled and tetrafluoroethylene pressure was released. Its content was then purged four times with nitrogen. Consumption of tetrafluoroethylene was 110 g.

[0095] 468 g of mixture were unloaded from reactor. This mixture was diluted in a separator funnel with 1.5 L water and neutralized with hydrochloric acid. The organic layer at the bottom was washed two times with 0.5 L of water and then finally separated from the top water layer, dried over MgSO.sub.4, filtered and distilled at 94° C. at a reduced pressure of 15 mbar.

[0096] 150 g of pure 1,4-bis(1,1,2,2-tetrafluoroethoxy)benzene were obtained.

[0097] The GWP.sub.100 for HFE1,4 has been determined at the University of Oslo according to established procedures, by measuring the integrated absorption cross section of infrared spectra over the region 3500-500 cm.sup.−1, the kinetic of reaction with OH radicals, and calculating the consequent atmospheric lifetime and radiative forcing efficiency. As a result of these measurements a GWP.sub.100 of 1.8 has been obtained.

[0098] HFE1,4 data relevant to GWP.sub.100:

[0099] Integrated absorption cross section at 3500-500cm.sup.−1:

[0100] 53.6 cm.sup.2 molecule.sup.−1 cm.sup.−1

[0101] Radiative forcing efficiency (calc)=0.165 W m.sup.−2

[0102] OH radicals kinetic k.sub.HFE1,4+OH=2×10.sup.−13 cm.sup.3 molecule.sup.−1 s.sup.−1 at 298K

[0103] Atmospheric lifetime of HFE1,4=2 months

[0104] GWP.sub.100=1.8

[0105] Electric and thermal properties of HFE1,4 in comparison with other commercially available hydrofluoroethers:

TABLE-US-00002 Volume Dielectric resistivity strength Dielectric GWP.sub.100 (ohm cm−1) (kV) constant NOVEC 7200 70 1.00E+08 30 7.3 NOVEC 7000 530 1.00E+08 40 7.4 HFE1,4 1.8 2.00E+9  45 6.2

[0106] Other physical properties of compounds according to the invention:

[0107] 1,4-Bis(1,1,2,2-tetrafluoroethoxy)benzene (HFE 1,4)

[0108] 1,3-Bis(1,1,2,2-tetrafluoroethoxy)benzene (HFE 1,3)

[0109] 1,2-Bis(1,1,2,2-tetrafluoroethoxy)benzene (HFE 1,2)

TABLE-US-00003 HFE1,4 HFE1,3 HFE1,2 Dielectric constant @1 kHz 6.2 7.84 Dielectric strength kV 45 Volume resistivity Ohm*cm 2E+09 1E+10 heat capacity cal/g° C., 0.34 viscosity (25° C.) cSt, 3.56 2.75 2.86 density (25° C.) g/cm3, 1.5 1.5 1.5 heat of vaporization kcal/kg 34 surface tension mN/m 28 pour point ° C. −10 −93 −87 Boiling point ° C. 202 192 206

[0110] The results show how the compounds of the invention have overall equal or improved properties when compared with existing commercial fluids used for similar purposes and have lower GWP. Heat transfer fluids comprising these compounds can be used in the method of the invention, particularly in the applications described i.e. in TCUs for production equipment such Etchers, Ashers, a Steppers and plasma enhanced chemical vapour deposition (PECVD) chambers, and/or in baths for thermal shock testing of semiconductor devices and/or for vapor phase soldering of semiconductor devices.