Method of surface preparation

Details Method of surface preparation Method of surface preparation

2000-01-13

2002-10-15

Dang, Thi (Department: 1763)

Semiconductor device manufacturing: process

Radiation or energy treatment modifying properties of...

C438S796000, C438S906000

Reexamination Certificate

active

06465374

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention pertains to a process for gas phase removal of contaminants such as oxides, organics and metals from the surface of a substrate.
The removal of contamination from a substrate is an important step in the semiconductor fabrication process. Trace metals and other contaminants can cause degradation of device performance if not removed from the substrate surface. Contamination, whether in the form of oxide, organics or metals, can arise from a number of sources including wet chemicals, photoresist, ion implantation and redeposition of sputtered materials from chamber surfaces during plasma processing.
Many different etching and cleaning techniques have been developed for various semiconductor processes. Typically in the past, wet etches, such as “RCA Clean”, dominated in semiconductor fabrication processes. Gradually, as device structures have shrunk and the move toward VLSI devices grown, dry etches have gained prominence. These dry etches include plasma and gas-based etches and many were developed originally for removing oxides and carbon-based contaminants.
For dry gas-phase metal removal, for example, several systems have been reported. U.S. Pat. Nos. 5,094,701 and 5,221,366 disclose use of beta-diketone and beta-ketoimine ligand forming compounds, which are dispersed in an oxidizing atmosphere. At a sufficient temperature, volatile metal-ligand complexes are reported to be formed and then sublimed from the surface. Temperatures of 200° C. to 300° C. are indicated to be required. U.S. Pat. Nos. 5,213,621, 5,213,622, and 5,332,444 disclose other ligand forming chemical reagents which reportedly can be used in a similar manner to form volatile metal-ligand complexes with surface impurities which then can be sublimed from the surface.
Other dry gas-phase removal techniques involve the use of ultraviolet radiation to generate cleaning radicals. Sugino et al. (IEIC Trans. Electron. Vol. E75-C, No. 7, July 1992) describe a system for removal of Fe and Al on a silicon surface using photoexcited chlorine radicals at approximately 20 Torr and 170° C. as a cleaning gas. U.S. Pat. No. 5,221,423 issued to Sugino discloses a method for removing Al, Fe, Na and Cr by irradiating chlorine gas at a partial chlorine pressure of 20 Torr to produce chlorine radicals. U.S. Pat. No. 5,178,721 issued to Sugino discloses a Uv radical generating cleaning method in which the pressure of the chlorine gas and the pathlength of the UV are varied to maximize radical generation and cleaning efficiency. In that system, the chlorine pressure ranges from 1 Torr to atmospheric pressure. Ito (Proc. Instit. for Environ. Studies 1991 p.808) discloses a method for cleaning using photoexcited chlorine radicals wherein the chlorine is delivered at a pressure of 20 Torr.
Commonly assigned U.S. Pat. No. 5,954,884 discloses a chlorine based dry-cleaning system appropriate for removing metal contaminants from the surface of substrate in which the metal contaminant is chlorinated and reduced to a volatile metal chloride by UV irradiation.
Along with the advances in process design, advances have been made in equipment design to facilitate efficient implementation of the ever-more complex treatment processes. To that end, commonly assigned U.S. application Ser. No. 08/955355 discloses an apparatus which provides for the dual use of a UV source to heat a substrate and to facilitate photochemistry necessary for the treatment of the substrate.
There continues, however, to be a need for improved processes for removal of contaminants from substrates such as semiconductor substrates and substrates in micromechanical devices and the like. This need is amplified by the increasingly stringent performance criteria associated with the continuing drive toward miniaturization of semiconductors.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed in one embodiment toward a gas phase process of removing contaminants from a semiconductor substrate without roughening the substrate. The method comprises the steps of irradiating the substrate in the absence of a halogen-containing gas followed by exposing the substrate to a halogen-containing gas in the absence of ultraviolet radiation. In another embodiment, the invention is directed toward a method of treating a semiconductor substrate to remove contaminants such as silicon oxides, organic and metallics from the surface of the substrate without excessive surface roughening and without destroying desirable features on the surface of the substrate such as shallow trench isolation. The method comprises the steps of heating the substrate via the application of ultraviolet radiation in the absence of a halogen-containing gas followed by exposing the heated substrate to a halogen-containing gas in the absence of ultraviolet radiation.
In yet another embodiment the invention is directed to a method of treating a substrate comprising the steps of performing an oxide etch, heating the substrate via the application of ultraviolet radiation in the absence of a halogen-containing gas, exposing the heated substrate to a halogen-containing gas in the absence of ultraviolet radiation and subsequently oxidizing the substrate.


REFERENCES:
patent: 4028135 (1977-06-01), Vig et al.
patent: 4167669 (1979-09-01), Panico
patent: 4443533 (1984-04-01), Panico
patent: 4522674 (1985-06-01), Ninomiya et al.
patent: 4540466 (1985-09-01), Nishizawa
patent: 4568632 (1986-02-01), Blum et al.
patent: 4615756 (1986-10-01), Tsujii et al.
patent: 4643799 (1987-02-01), Tsujii et al.
patent: 4678536 (1987-07-01), Murayama et al.
patent: 4687544 (1987-08-01), Bersin
patent: 4689112 (1987-08-01), Bersin
patent: 4693779 (1987-09-01), Okuhira et al.
patent: 4705593 (1987-11-01), Haigh et al.
patent: 4711790 (1987-12-01), Moirshige
patent: 4741800 (1988-05-01), Yamazuki
patent: 4749440 (1988-06-01), Blackwood et al.
patent: 4756047 (1988-07-01), Hayashi et al.
patent: 4857382 (1989-08-01), Liu et al.
patent: 4871416 (1989-10-01), Fukuda
patent: 4919077 (1990-04-01), Oda et al.
patent: 4986216 (1991-01-01), Ohmori et al.
patent: 5022961 (1991-06-01), Izumi et al.
patent: 5022961 (1991-06-01), Izumi et al.
patent: 5094701 (1992-03-01), Norman et al.
patent: 5112437 (1992-05-01), Watanabe et al.
patent: 5119760 (1992-06-01), McMillan et al.
patent: 5178721 (1993-01-01), Sugino
patent: 5183531 (1993-02-01), Terakado
patent: 5198388 (1993-03-01), Kawai
patent: 5213621 (1993-05-01), Irankovits et al.
patent: 5213622 (1993-05-01), Bohling et al.
patent: 5217559 (1993-06-01), Moslehi et al.
patent: 5221366 (1993-06-01), Roberts et al.
patent: 5221423 (1993-06-01), Sugino et al.
patent: 5228206 (1993-07-01), Hiatt et al.
patent: 5288333 (1994-02-01), Tanaka et al.
patent: 5288684 (1994-02-01), Yamazaki et al.
patent: 5332442 (1994-07-01), Kubodera et al.
patent: 5332444 (1994-07-01), George et al.
patent: 5356514 (1994-10-01), Kinoshita
patent: 5439553 (1995-08-01), Grant et al.
patent: 5470799 (1995-11-01), Itoh et al.
patent: 5571375 (1996-11-01), Izumi et al.
patent: 5578133 (1996-11-01), Sugino et al.
patent: 5580421 (1996-12-01), Hiatt et al.
patent: 5589422 (1996-12-01), Bhat
patent: 5725677 (1998-03-01), Sugino et al.
patent: 5762755 (1998-06-01), McNeilly et al.
patent: 5789755 (1998-08-01), Bender
patent: 5814156 (1998-09-01), Elliott et al.
patent: 5814562 (1998-09-01), Green et al.
patent: 5922219 (1999-07-01), Fayfield et al.
patent: 5954644 (1999-09-01), Dettling et al.
patent: 5954884 (1999-09-01), Lawing et al.
patent: 5992429 (1999-11-01), Peckman
patent: 5998305 (1999-12-01), Holmer et al.
patent: 5998766 (1999-12-01), Mizosaki et al.
patent: 6015503 (2000-01-01), Butterbaugh et al.
patent: 6015759 (2000-01-01), Khan et al.
patent: 6065481 (2000-05-01), Fayfield et al.
patent: 1180187 (1970-02-01), None
patent: 2 181 458 (1987-04-01), None
patent: 1-235232 (1983-09-01), None
patent: 62116723 (1987-05-

Affiliated with

Also associated with

Rating

Method of surface preparation does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of surface preparation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of surface preparation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2997796