FR2590507A1 - NITROGEN TRIFLUORIDE AS IN SITU CLEANING AGENT AND CLEANING METHOD - Google Patents

Abstract

There is provided a pickling agent and in situ cleaning or pickling process for pieces of equipment used in a semiconductor wafer or chip manufacturing process by the chemical vapor deposition method. Nitrogen trifluoride is used as the ideal stripping agent for in situ cleaning of films deposited on pieces of equipment during this manufacturing process. The process of the invention uses nitrogen trifluoride as stripping agent which is introduced into a reactor under partial pressure for a time sufficient to clean the deposited film; this agent and this method are ideally suited for removing substantially all of the deposited amounts of silicon nitride and polysilicon, titanium silicide, tungsten silicide, refractory metals and their silicides. Application in particular to the electronic components industry by the use of chemical vapor.

Description

The invention generally relates to a cleaning agent and a

  method of cleaning nacelles and tubes used in installations

  manufacture of chips or silicon wafers. More particularly

  In particular, the present invention relates to the use of trifluoro

  nitrogen as a cleaning agent to remove nitride from

  silicon and polycrystalline silicon films which cover the

  face of nacelles and tubes used in the manufacturing process

  by depot, by chemical vapor, on slices or chips-of semi-con-

  transducers. In addition, the present invention relates to a method of

  residual silicon films that remain on nacelles and tubes used in chip manufacturing facilities or

slices of semiconductors.

  Nacelles, tubing and other similar quartz accessories used in the manufacture of chemical discharge semiconductor chips are contaminated with polycrystalline silicon, silicon nitride, tungsten, titanium or other substances are deposited on the substrate of the wafer or chip during the chemical vapor deposition phase. To obtain a chemical vapor deposition that is both precise and pure on a substrate, it is essential to clean or strip the polluting substances that cover the nacelles, tubes or other pieces of quartz equipment used in

  the manufacture of semiconductor chips or chips. However,

  important problems arise with conventional cleaning agents

  and also because of the cleaning processes of the nacelles, tubes

  and other quartz equipment used in manufacturing facilities

  cation by depot with chemical vapors.

  Conventional cleaning or pickling agents and methods require extraction of the chemical vapor deposition tube from the manufacturing cat for cleaning purposes. The dismantling of the tube is not only a relatively long operation, but also a factor

  increase in cost prices. The tube, the nacelles and other

  quartz equipment is then cleaned with acid, and for this purpose we generally use acids such as hydrofluoric acid, acid

  nitric acid, hydrochloric acid, or phosphoric acid. These net agents

  require the use of dry-cleaning techniques that

  entail significant risks to health, safety and the envi-

  ronment. In addition, because of the high temperatures generated in the manufacturing equipment during a chemical vapor deposition operation, conventional cleaning or stripping agents require long waiting periods to allow the Quartz equipment

  cool before you can start cleaning.

  Therefore, it has been found that it is better to

  a cleaning agent to carry out the in-situ cleaning of the

  be deposition and associated equipment. A cleaning process

  in-situ would thus practically eliminate not only the total

  time or non-productive time that accompanies the adoption of

  cleaning agents and routine cleaning processes, but

  the risks to health, safety and the envi-

  the use and handling of conventional acidic cleaning agents

  c. Under these conditions, the object of the present invention is to provide a cleaning or pickling agent allowing the in-situ cleaning of apparatus, tubes, nacelles and associated quartz equipment in order to

  remove them from adherent chemical vapor deposits.

  Another object of the invention is to provide a method for cleaning or in-situ stripping tubes, nacelles and equipment

  of quartz apparatus used for chemical vapor deposition.

  Furthermore, the present invention aims to provide a

  cleaning or stripping for in-situ cleaning, in order to avoid

  the use of wet cleaning processes.

  Another object of the present invention is to provide a

  in-situ cleaning, which eliminates the need to adopt

  wet cleaning techniques.

  Furthermore, it is an object of the present invention to use trifluoro

  nitrogen as a cleaning or stripping agent for the net.

  in-situ cleaning of tubes, nacelles and associated quartz equipment

  chemical vapor deposition apparatus.

  On the other hand, it is an object of the present invention to provide a

  process of cleaning or stripping tubing, nacelles and equipment therewith, of quartz, with chemical vapor deposition apparatus, in which nitrogen trifluoride is used as a cleaning agent or

stripping.

  However, the object of the invention is also to provide a cleaning or pickling agent which makes it possible to eliminate the silicon nitride,

  polycrystalline silicon, titanium, tungsten and other

  these deposited on semiconductor wafers in a test device.

p8t by chemical vapor.

  An additional object of the present invention is to provide 3 -

  a cleaning or pickling agent and a method for

  in-situ elimination of silicon nitride, polycrystalline silicon, titanium, tungsten and other substances deposited on chips or

  semiconductor wafers in a chemical vapor deposition apparatus

  without removing or attacking the substrate of the slice or chip. Finally, it is an object of the present invention to provide an in-situ cleaning or stripping process using nitrogen trifluoride.

  to eliminate silicon nitride, polycrystalline silicon,

  tane, tungsten or other substances deposited on

  1o conductors in a chemical vapor deposition apparatus.

  These different goals, features and benefits, as well as others, will come out more during the reading of the

  detailed description which follows and relates to a preferred embodiment of

of the invention.

  According to the present invention, there is provided a cleaning or pickling agent for the removal of silicon nitride, silicon poly =

  cries tailin, titanium: tbangstbene or other substances essential

  deposited on semiconductor wafers or chips during a chemical vapor deposition operation, using for this purpose the Nde. nacelles and other quartz equipment

  used in the growth of silicon nitride, silicon and poly

  cries of linen, turkey, titanium silicide or other metamerica

  fractures and their properties, as well as other films, can be cleaned by nitrogen trifluoride in their respective

  without having to carry out lemontages which take a long time.

  This in-situ clean-up makes it possible to obtain cleaner reaction chambers, and nitrogen trifluoride, which is a gas at high temperatures.

  ambient, can be used with chemical vapor deposition equipment

  in the manufacture of chips and slices of semiconductors. In

  In addition, the in-situ cleaning of tubes, nacelles and equipment

  companies used in growth by chemical vapor deposition of nitro-

  re of silicon, polycrystalline silicon, tungsten or titanium silicide, or other refractory metals or their silicides, may be

performed without the aid of a plasma.

  It was found important that trifluoride pickling

  nitrogen, in contrast to the technical processes of wet pickling

  mide, attack only weakly or not at all quartz equipment, whatever it is. It was found that the typical levels of nitrogen trifluoride attack on quartz equipment reached 5 - 4-

  at 10 X / min. This significant reduction in the degree of attack of the team

  quartz compared to the figures found in conventional wet pickling processes,

  the useful life of the equipment and also to maintain the critical dimensions

  ticks of quartz material. More importantly, perhaps, is the fact that the nitrogen trifluoride cleaning of the tube that serves as the deposition chamber generates a smaller number of foreign particles, which results in a cleaner growth of the film on the substrate. of the

  slice or chip during the dep8t process.

  According to a preferred embodiment of the present invention, there is provided a method for cleaning tubes, nacelles and equipment

  in quartz associated therewith, used in chemical vapor deposition. Sui-

  In this process, after a deposition operation, trifluoride is introduced.

  nitrogen in a reaction tube by chemical vapor deposition, the

  nitrogen fluoride then being at a temperature above 3500C. It is also possible to introduce into the reaction tube any quartz cladding which must have a growth of silicon nitride or polycrystalline silicon film. The reaction tube is backfilled at a pressure of 300 to 600 Torr and allowed to soak for a period of time.

  enough time to clean the tube and any quartz material introduced

  duit in this tube. The residual gases of nitrogen trifluoride are removed from the reaction tube by purging the tube with nitrogen. After this purge, we can open the reaction tube, remove the quartz equipment and cleaned and prepare the reactor for a new operation

deposit.

EXAMPLE 1

  A quartz nacelle containing 5 to 6 microns of nitride

  silicon and polycrystalline silicon was placed in a highly polished

  read from chemical vapor deposition at 2800C. This tube was evacuated under a pressure of O Torr and then filled with NF3 at 300 Torr, before being allowed to soak for 15 minutes. Finally, the tube was pumped to the base, then purged with N2 and refilled with

  nitrogen. The nacelle was removed from the reactor and a visual inspection was

  that it was perfectly clean, with the exception of one

  film of noticeably spooky appearance. The origin of this film in the

  Textile lure has been attributed to some oxide having escaped stripping.

  The pickling rate recorded was about 85 A / min.

EXAMPLE 2

  Silicon oxide semiconductor chips having been placed with

  a polycrystalline silicon layer of about 2 microns in a reaction

  designed for chemical vapor deposition. The same rules were observed

  Only in Example 1. In this case also the polycrystalline silicon in the state of silicon oxide layer was reduced on the chip substrate. This substrate was attacked only where there were pinholes in the silicon oxide or when it was believed that no

  oxide existed under polycrystalline silicon. The stripping rate

was about 500 A / min.

EXAMPLE 3

  The same process was adopted as in Examples 1 and 2 above.

  above, except that the temperature was raised from 3800C to 500oC and

  the pressure of 200 to 600 Torr. Visual examination of the substrates and the

  The same test subject revealed that almost all of the silicon nitride and polycrystalline silicon had been cleaned. Pickling rates varied exponentially with increasing temperature and pressure. The etching rates were as follows: Silicon Nitride Temperature (OC) Pressure (Torr) Decapac Rate Polycrystalline Silicon Temperature (oC) Pressure (Torr) (% / min.) Stripping Rate o (A / min.) Temperature (oC) - 6 - Pressure (Torr) Pickling rate (X / min.)

500 200

500 400

500 600

  The chemical reactions according to the present invention essentially as follows:

> 3500C

2NF F2 + SixNy 2 F2 + If are taking place

NF2-NF2 + F2

  -Â SiF4t + N2 t - SiF. t It is important to note that both nitrogen trifluoride and its

  derived N2F4 are highly toxic and explosive under pressure or

  tact of reducing agents. However, since they would normally be used under reduced pressure and / or in low concentrations, this should not be a problem in the practice of the present invention. Accordingly, it is seen that the present invention provides for the use of a stripping gas and a novel process for the cleaning of tubes used for chemical vapor deposition, tubes and associated quartz equipment parts. , which allows to quickly and efficiently clean quartz parts used in the manufacture by chemical vapor deposition of semi-conductors in the form of slices or

fleas.

  Although the invention has been described with particular reference to

  With respect to certain preferred applications, it is obvious to those skilled in the art that modifications in both form and detail may be made in the practice of the invention without departing from the basic principles of the invention. -this. For example,

  much lower pressures (and circulation) could be

  NF3) to achieve the same result, although pickling rates in this case would be slightly lower than in the case of

Example 3

Claims (33)

R E V E N D I C A T I ONS   1. A pickling agent for removing material deposited on equipment parts subject to deposition by the action of chemical vapor, characterized by the. this agent comprises nitrogen trifluoride.   2. Pickling agent according to Revehdication 1, characteristics   rised by the fact that the material thus deposited comprises silicon nitride.   3. Pickling agent according to Claim 1, characterized   rised by the polycrystalline fact. 4, Agent of Righteousness by the fact re titanium. 5. Risk agent by the fact re tungsten. 6. Agent risb by the fact refractory.   A reagent according to the fact that the deposited material comprises silicon pickling according to whether the pickling material according to the pickling material according to the pickling material according to the material of the filed claim comprises the filed claim comprises the filed claim comprising the filed claim. comprises 1, characteristics a siliciu- 1, characteristics a siliciu- 1, characteristics a metal 1, characteristics a siliciu- re refractory metal.   8, A method of cleaning equipment items submitted to a deposit by the action of chemical vapor, using the pickling agent according to claim 1, and characterized by the following steps which consist in: a) providing a reactor of chemical vapor deposition, said reactor comprising a reactor quartz tube on which a film of material has been deposited; b) heating the reactor to a temperature sufficient to allow the cleaning of the film of material; c) evacuate the reactor;   (d) introducing nitrogen trifluoride into the reaction   under positive pressure for a time sufficient to allow said film of material to be cleaned, and   (d) purge the reactor to remove the trifluoride nitrogen.   9. Process for cleaning equipment parts subject   chemical vapor deposition according to Claim 8,   the fact that the phase of providing for a reorganization   chemical vapor deposition actor further includes the   in said reactor, nacelles or other equipment used for chemical vapor deposition and covered with a film of matter.   10. The process of cleaning equipment used in   in the chemical vapor deposition according to Claim 8, characterized in that said film of matter comprises in addition silicon nitride.   11. Process for cleaning equipment parts submitted   chemical vapor deposition according to Claim 8,   characterized by the fact that said film of matter comprises in particular be polycrystalline silicon.   12. Process for cleaning equipment parts submitted   chemical vapor deposition according to Claim 8,   characterized by the fact that said film of matter comprises in particular   titanium silicide, 13, Process for the cleaning of equipment parts subject to   chemical vapor deposition according to Claim 8,   characterized by the fact that said film of matter comprises in particular be tungsten silicide.   14. Process for cleaning equipment parts submitted   chemical vapor deposition according to Claim 8,   characterized by the fact that said film of matter comprises in particular be a refractory metal.   15. A method of cleaning equipment parts used in the manufacture of components by chemical vapor deposition according to Claim 8, characterized in that said film of material further comprises a silicide of refractory metal.   16. Process for cleaning equipment parts submitted   chemical vapor deposition according to Claim 8,   characterized in that the material film further comprises silicon nitride.   17. Process for cleaning equipment parts subject to   chemical vapor deposition according to Claim 9,   characterized in that the material film further comprises polycrystalline silicon.   -9- 18. Process for cleaning equipment parts subject to   chemical vapor deposition according to Claim 9,   characterized by the fact that said film of matter comprises in particular   be titanium silicide. 19. Process for cleaning parts of equipment subject to   chemical vapor deposition according to Claim 9,   characterized by the fact that said film of matter comprises in particular be tungsten silicide.   20. Process for cleaning equipment parts subject to   chemical vapor deposition according to Claim 9,   characterized by the fact that said film of matter comprises in particular be a refractory metal.   21. Process for cleaning equipment parts subject to   chemical vapor deposition according to Claim 9,   characterized by the fact that said film of matter comprises in particular   be a refractory metal silicide.   22. Process for cleaning equipment parts   chemical vapor deposition according to Claim 8,   the fact that the reactor is heated to a temperature of at least 350 C.   23. Process for cleaning equipment parts submitted   chemical vapor deposition according to Claim 9,   characterized by the fact that said reactor is heated at a time   not less than 350 ° C.   24. Process for cleaning equipment parts subject to   chemical vapor deposition according to one or other of the   8 or 9, characterized in that said pressure   positive is not more than about 600 Torr.   25. Process for cleaning equipment parts subject to   chemical vapor deposition according to one or other of the   8 or 9, characterized in that said reactor   is evacuated to about 0.00 Torr.   26. Process for cleaning subject equipment   chemical vapor deposition according to one or other of the   8 or 9, characterized in that the said phase of purge consists of: -   a) pumping the reactor at the base pressure, b) purging the reactor with nitrogen gas, and c) filling the reactor against the current with nitrogen gas.   27. Method for cleaning chips or slices at half   conductors using the stripping agent according to the   1, characterized by the steps of a) providing a reactor for depositing by va-   chemical fear and introduce slices or chips   conductors comprising a film of material to be cleaned;   (b) heat the reactor to a sufficient temperature   health to allow the cleaning of said mason film; c) evacuate the reactor; d) introducing nitrogen trifluoride into the reactor under positive pressure and for a time sufficient to allow cleaning of said material film, and e) purging the reactor to remove trifluoride therefrom nitrogen.   28. Process for cleaning slices or chips at half   conductors according to claim 27, characterized in that said phase which consists in providing a reactor   for chemical vapor deposition also consists of   introducing nacelles or other quartz elements into said reactor for the deposition of chemical vapor,   which comprise a film of a material to be removed.   29. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said film of composite material   additionally takes silicon nitride.   30. Process for cleaning slices or chips at half   conductor according to any one of Claims 27 or   28, characterized in that said film of composite material takes polycrystalline silicon.   31. Method for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said film of composite material   additionally takes titanium silicide.   32. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said film of composite material   In addition, it takes tungsten silicide.   33. Process for cleaning slices or chips at half - 11 -   conductor according to Claim 27 or   28, characterized in that said film of composite material   additionally takes a refractory metal.   34. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said film of composite material   In addition, it takes refractory metal silicide.   35. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said reactor is heated   at a temperature not lower than about 3500C.   36. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized in that said positive pressure is   not more than about 600 Torr.   37. Process for cleaning slices or chips with semi-con   conductors according to any one of Claims 27 or 28,   characterized by the fact that said reactor is evacuated under a pressure of about 0.01 Torr.   38. Process for cleaning slices or chips at half   conductor according to Claim 27 or   28, characterized not that said purge phase   to: a) pump the reactor to the base pressure; b) purging the reactor with nitrogen gas, and   (c) fill the reactor with nitrogen gas current.