Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – On insulating substrate or layer
Reexamination Certificate
1997-11-03
2001-12-11
Wilozewski, Mary (Department: 2822)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
On insulating substrate or layer
C438S162000, C438S486000, C438S487000
Reexamination Certificate
active
06329229
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for fabricating semiconductor devices such as various transistors and integrated circuits.
BACKGROUND OF THE INVENTION
In recent years, methods and apparatus which use lasers to manufacture semiconductor devices have been developed. Examples of these methods and apparatus include laser etching, or laser scribing, in which films are etched and patterned, laser annealing in which the crystalline state of films or their surfaces are changed by laser irradiation, and laser doping in which an impurity is diffused into films or their surfaces by laser irradiation within an ambient containing the impurity.
In these conventional semiconductor fabrication methods using lasers, a substrate already processed by other film formation apparatus or etching apparatus is first placed in position inside a laser processing apparatus. The inside of this apparatus is evacuated and the substrate is heated and then the substrate is processed by laser radiation. Consequently, the productivity is very low.
SUMMARY OF THE INVENTION
It is a object of the present invention to provide a method of fabricating semiconductor devices with improved productivity.
It is another object of the invention to provide an apparatus capable of fabricating semiconductor devices with improved productivity.
An apparatus according to the present invention comprises a multi-chamber system consisting of a film formation apparatus (e.g., a plasma CVD apparatus, a sputtering apparatus, a thermal CVD apparatus, or a vacuum evaporation apparatus), an etching apparatus, a doping apparatus (e.g., a plasma doping apparatus or an ion implanter), a thermal processing apparatus (e.g., a thermal diffusion apparatus or a thermal crystallization apparatus), vacuum apparatus such as a preliminary chamber, and a laser processing apparatus (e.g., a laser etching apparatus, a laser annealing apparatus, or a laser doping apparatus). The novel apparatus performs processing without exposing each substrate to the atmosphere at all. In this system, the evacuation an be effected in a greatly shortened time. In addition, when the substrate is transported, it is protected from contamination.
Also, various annealing methods making use of infrared light irradiation rather than laser irradiation are available. For example, an amorphous silicon film formed on a glass substrate is crystallized by heating and then irradiated with infrared radiation. As a result, the crystallinity can be enhanced further. Infrared radiation is absorbed more readily by the thin silicon film than by the glass substrate. Only the thin silicon film can be heated without heating the glass substrate very much. This is advantageous. Furthermore, it is considered that the obtained effect is comparable to the effect produced by a thermal anneal conducted above 1000° C.
An anneal using such irradiation of infrared radiation can be completed within several minutes. Therefore, this is known as a rapid thermal anneal (RTA). This anneal can be advantageously conducted after an insulating film is formed on a semiconductor layer. In this case, the level in the interface between the semiconductor layer and the insulating film can be reduced, so that the interface characteristics can be enhanced. For example, after an active layer (in which a channel formation layer is formed) for an insulated-gate field-effect transistor is formed, a silicon oxide film becoming a gate-insulating film is formed. Subsequently, a rapid thermal anneal process is carried out. In this way, he characteristics at and around the interface between the channel and the gate-insulating film which are an important factor for the insulated-gate field-effect transistor can be improved.
A semiconductor processing system in accordance with another aspect of the present invention comprises:
at least one processing apparatus for irradiating laser light or other light (e.g. an infrared light) as strong as laser light;
at least one vacuum film formation apparatus (evacuable chamber) by vapor phase deposition method (for example, plasma CVD apparatus low pressure CVD (LPCVD) apparatus, atmospheric pressure CVD (APCVD) apparatus, sputtering film formation apparatus (sputter apparatus) and the like),
wherein laser light or strong light is irradiated to a non-single crystal semiconductor film such as an amorphous semiconductor film, a poly-crystal semiconductor film, a micro-crystal semiconductor film formed on a substrate in the processing apparatus for irradiating laser light or other light as strong as laser light;
wherein said substrate is transferred from said processing apparatus for irradiating laser light or another light as strong as laser light to another evacuable chamber without being exposed to outside air, and prescribed process is performed;
said irradiation of laser light or other light as strong as laser light being performed in oxidizing atmosphere such as oxygen atmosphere, or in nitrogenizing (nitriding) atmosphere such as ammonia atmosphere, thus improving crystal character of the non-single crystal semiconductor film, performing oxidation of its surface or formation of an oxide film on the surface (in the case of oxidizing atmosphere), or performing nitrogenization of its surface or formation of a nitride film on the surface (in the case of nitrogenizing atmosphere). The semiconductor processing system has a means for transferring an object from the light processing chamber to the evacuable chamber, or vice versa without exposing the object to air.
It is necessary that the processing apparatus for irradiating laser light or other light as strong as laser light has function of irradiating laser light or other light as strong as laser light, has a means of introducing a gas needed, and has an exhaustion means of making the atmosphere low pressure. Excimer laser, YAG laser of various types, ruby laser and the like can be utilized as laser light. As non-coherent light source other than laser, rare gas lamp such as xenon lamp or krypton lamp, halogen lamp and the like can be utilized. A wide range of wavelength from infrared light to ultraviolet light can be utilized as wavelength of light source. To prevent temperature increase of the substrate, it is preferable light irradiation is performed in pulses. It is desirable that the pulse width is 1 &mgr;sec or less.
As a vacuum film formation apparatus, a plasma CVD apparatus, a low pressure CVD (LPCVD) apparatus, an atmospheric pressure CVD (APCVD) apparatus, or a sputtering film formation apparatus (a sputter apparatus) can be utilized.
Other than above mentioned apparatuses as a vacuum processing apparatus, a heating process apparatus (a heat-treatment chamber) in each type of atmosphere, an ion injection apparatus, an etching chamber, an apparatus for carrying substrates in and our can be connected. It is preferable each of these apparatuses has a gas introducing system and a gas exhaustion system for gas needed by each. It is preferable these apparatuses are connected to a common transportation chamber which exclusively transports substrates.
Substrates are transported without being exposed to the outside air so that things to be processed (for example, a silicon film on a substrate) would not be polluted in each process.
A method in accordance with the present invention comprises:
irradiating laser light or other light as strong as laser light to a non-single crystal semiconductor film in nitrogenizing or oxidizing atmosphere, thus nitrogenizing or oxidizing the non-single crystal semiconductor surface and improving crystal character of said non-single crystal semiconductor film; and
depositing an insulating film on the oxide film or the nitride film.
An amorphous silicon film deposited by a plasma CVD method or a low-pressure heat CVD method can be utilized as the non-single crystal semiconductor film. By annealing an amorphous semiconductor film like this at 650° C. or less, crystallized polycrystal or microcrystal semiconductor film can be also utilized. Laser light or other light
Shimada Hiroyuki
Takemura Yasuhiko
Takenouchi Akira
Yamazaki Shunpei
Nixon & Peabody LLP
Robinson Eric J.
Semiconductor Energy Laboratory Co,. Ltd.
Wilozewski Mary
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