WO2006073165A1 - Semiconductor device, and method and apparatus for manufacturing same - Google Patents

Semiconductor device, and method and apparatus for manufacturing same Download PDF

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Publication number
WO2006073165A1
WO2006073165A1 PCT/JP2006/300053 JP2006300053W WO2006073165A1 WO 2006073165 A1 WO2006073165 A1 WO 2006073165A1 JP 2006300053 W JP2006300053 W JP 2006300053W WO 2006073165 A1 WO2006073165 A1 WO 2006073165A1
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Prior art keywords
laser
semiconductor device
crystal
irradiation
semiconductor film
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PCT/JP2006/300053
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French (fr)
Japanese (ja)
Inventor
Junichiro Nakayama
Ikumi Itsumi
Tetsuya Inui
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Sharp Kabushiki Kaisha
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Publication of WO2006073165A1 publication Critical patent/WO2006073165A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
    • H01L21/02675—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth using laser beams
    • H01L21/02683—Continuous wave laser beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/0242—Crystalline insulating materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02422—Non-crystalline insulating materials, e.g. glass, polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
    • H01L21/02488—Insulating materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02524—Group 14 semiconducting materials
    • H01L21/02532—Silicon, silicon germanium, germanium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02587—Structure
    • H01L21/0259—Microstructure
    • H01L21/02595—Microstructure polycrystalline
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
    • H01L21/02675—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth using laser beams
    • H01L21/02678—Beam shaping, e.g. using a mask
    • H01L21/0268—Shape of mask
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
    • H01L21/02675—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth using laser beams
    • H01L21/02686—Pulsed laser beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
    • H01L21/02691—Scanning of a beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
    • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
    • H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
    • H01L21/84—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being other than a semiconductor body, e.g. being an insulating body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66742—Thin film unipolar transistors
    • H01L29/6675—Amorphous silicon or polysilicon transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H01L29/78651—Silicon transistors
    • H01L29/7866—Non-monocrystalline silicon transistors
    • H01L29/78672—Polycrystalline or microcrystalline silicon transistor

Definitions

  • the present invention relates to a semiconductor device obtained by crystallizing an amorphous semiconductor material using a laser, a method of manufacturing the same, and a manufacturing apparatus.
  • a thin film transistor in which a semiconductor device is formed on a thin film material is used for a display unit and a pixel controller in an active matrix liquid crystal display device, and an amorphous material is mainly used as the thin film material. ing. Furthermore, in order to drive the TFT at high speed, conventionally, an amorphous semiconductor film is used, and the material characteristic is improved by crystallizing the channel region. This is because the mobility of carriers in the entire portion of the atomic arrangement of crystals is several hundred times greater than that in the amorphous portion. In the case of a polycrystal, carriers are scattered at grain boundaries, so it is desirable to make the grains larger and to be single crystals in the channel region.
  • FIGS. 8A to 8B Crystals formed by lateral growth will be described using FIGS. 8A to 8B.
  • 8A-8B are front views of a film crystallized using the lateral crystal growth method
  • FIG. 8A is a crystal when using a mask with a small width
  • FIG. 8B is a size! / Width
  • a laser beam is pulsed to the amorphous semiconductor film using a mask to completely melt this region. Thereafter, the melted semiconductor film is re-solidified by cooling, but at this time, a force near the boundary with the solidified solid portion also causes peculiar crystallization of the crystal length L1 in the lateral direction. As shown in FIG.
  • These lateral crystals 71, 72 are large single crystals having a length from the completely melted end to the ridge 73, and when this direction is taken in the TFT channel direction, the grains are perpendicular to the carrier flow. There is no world !, so good characteristics can be obtained.
  • the SLS method is a method for further extending the crystal length, and as shown in JP-A 2000-505241 (patent document 1), lateral crystallization can be continued using this crystal as a seed. s
  • FIGS. 9A to 9D are front views of films crystallized using the S LS method.
  • the laser irradiation portion is shifted by moving (shifting) the sample (amorphous semiconductor film) by a distance L2 with respect to the rectangular mask laser and irradiating the laser.
  • 83 melts completely and resolidifies.
  • FIG. 9B since a single preceding crystal grain is taken over as a seed, a large single crystal of crystal length L 2 + crystal length L 3 can be obtained.
  • FIGS. 9C and 9D by repeating this shift and laser irradiation, a single crystal of a desired length can be obtained.
  • the ridge in the last region where the laser irradiation is repeated remains, which poses a problem for the subsequent device fabrication process.
  • a film such as a gate portion or a contact portion is deposited on a region including a ridge portion of a semiconductor film
  • the film thickness is limited, and the possibility of degradation of the characteristics is further increased. It is also an obstacle in terms of micronization.
  • Patent Document 2 a laser beam intensity modulation using an attenuator is proposed in Japanese Patent Application Laid-Open No. 2003-509845.
  • Patent Document 3 discloses a method for irradiating light passing through a mask below the diffraction limit in order to reduce the height of the ridge in the region crystallized by the SLS method. Have been described. In this method, light is irradiated to the entire crystallized region, so that the protrusions are reduced but the surface irregularities become large, which may cause deterioration of the TFT characteristics. In addition, it is necessary to limit the direction of crystallization to one direction.
  • Patent Document 1 JP 2000-505241
  • Patent Document 2 Japanese Patent Application Publication No. 2003-509845
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2003-309080
  • the present invention has been made to solve the above problems, and is a novel method capable of reducing the surface protrusion height (ridge) in the last region where laser irradiation is repeated in the SLS method.
  • An object of the present invention is to provide a method of manufacturing a semiconductor device, a manufacturing apparatus, and a semiconductor device manufactured by them.
  • the semiconductor device of the present invention has a basic structure in which a semiconductor film is formed on a substrate.
  • the semiconductor film is characterized in that it has a laterally grown crystal, and the height of the surface protrusion is smaller than the thickness of the semiconductor film at the end of the laterally grown crystal.
  • the laterally grown crystal is preferably a crystal grown by laser irradiation to the semiconductor film.
  • the laterally grown crystal is laterally bonded to the laser irradiation by the laser irradiation. It is preferable that the region is a region where crystal growth is expanded by moving stepwise in the surface direction of the semiconductor film so as to inherit the crystal-grown portion and inheriting the crystal of the portion.
  • the laterally grown crystal is formed by utilizing light having passed through a slit or pattern below the diffraction limit of the surface protrusion height force at the end of the transverse crystal growth. It is preferable that the film thickness of the semiconductor film be made lower by irradiating a laser having an energy lower than that of the above-mentioned laser.
  • a semiconductor device is characterized in that the laser having energy lower than that of the laser for forming the laterally grown crystal is any one of the following (1) to (3): The power of being produced by using is more preferable!
  • the semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
  • laser irradiation for crystal growth in the lateral direction in the semiconductor film may be performed by stepwise moving so as to take over a portion of the semiconductor film on which crystal growth has been performed. preferable.
  • a laser having energy lower than that of the laser for forming the laterally grown crystal is
  • the semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
  • a mask having a slit or pattern below the diffraction limit is used to perform laser irradiation with energy lower than that of the laser crystal grown in the lateral direction. It is preferred to control the energy dose by using
  • the present invention also provides a semiconductor device manufacturing apparatus suitably used for the above-described method of manufacturing a semiconductor device of the present invention.
  • the semiconductor device manufacturing apparatus of the present invention is characterized by including a first laser oscillator, a second laser oscillator, and a controller for controlling these two laser oscillators.
  • the energy of the laser generated from the second laser oscillator is lower than the energy of the laser generated by the first laser oscillator.
  • the wavelength of the laser generated from the first laser oscillator is a wavelength which is easily absorbed by the semiconductor film
  • the wavelength of the laser generated by the second laser oscillator is a substrate or a semiconductor film in a melted state. It is more preferable that the wavelength is easily absorbed by
  • the semiconductor film formed on the substrate is irradiated with a laser to cause the semiconductor film to grow laterally and to grow crystals laterally, which is lower than the laser which is caused to grow crystals laterally.
  • a laser In the method of manufacturing a semiconductor device in which the height of the surface protrusion at the end of the laterally grown crystal is made smaller than the film thickness of the semiconductor film by irradiating a laser of Also provided is a mask, characterized in that it has slits or patterns below the diffraction limit, which are used for the laser irradiation of energy.
  • a semiconductor film formed on a substrate is irradiated with a laser, and the semiconductor film is laterally grown by laterally growing crystals, and energy is lower than that of the laser grown by laterally growing crystals.
  • a manufacturing apparatus comprising a mask having the following slits or patterns.
  • the method of manufacturing a semiconductor device, the mask, and the apparatus for manufacturing a semiconductor device of the present invention it is not necessary to require an apparatus such as an attenuator or a driving system thereof unlike the prior art. It is possible to provide a semiconductor device in which the height of the surface protrusions at the end of crystallization which is not so serious is smaller than the thickness of the semiconductor film.
  • Such a semiconductor device has an effect of improving the TFT characteristics as compared with the conventional one. More specifically, it is effective in reducing the threshold voltage, reducing the variation in threshold voltage, and reducing the subthreshold coefficient.
  • process point of view also makes it possible to thin the film thickness of the gate oxide film by eliminating the protrusion at the end of crystallization, which improves throughput and further improves TFT characteristics. It will be possible.
  • FIG. 1 is a schematic cross-sectional view of a semiconductor device of the present invention.
  • FIG. 2A is a plan view of a semiconductor film crystal in the semiconductor device of the present invention.
  • FIG. 2B is a cross-sectional view of the semiconductor film in the semiconductor device of the present invention.
  • FIG. 3A is a view schematically showing a mask preferably used in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 3B is a view schematically showing a mask preferably used in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 3C is a view schematically showing a mask suitably used in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 3D is a view schematically showing a mask suitably used for the method for manufacturing a semiconductor device of the present invention.
  • FIG. 4A is a view schematically showing a suitable laser light irradiation method in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 4B is a view schematically showing a suitable laser light irradiation method in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 5 is a diagram conceptually showing an example of an apparatus that can be used in the method of manufacturing a semiconductor device of the present invention.
  • FIG. 6 A diagram conceptually showing a preferred example of a semiconductor device manufacturing apparatus of the present invention.
  • FIG. 7 is a graph illustrating an outline of a relationship between irradiation time and output (irradiance) of the first laser beam and the second laser beam in the semiconductor device manufacturing apparatus of the present invention.
  • FIG. 8A is a plan view of a film crystallized using a lateral crystal growth method.
  • FIG. 8B is a plan view of a film crystallized using a crystal lateral growth method.
  • FIG. 9A is a plan view of a film crystallized using SLS method.
  • FIG. 9B is a plan view of a film crystallized using SLS method.
  • FIG. 9C is a plan view of a film crystallized using SLS method.
  • FIG. 9D is a plan view of a film crystallized using an SLS method.
  • FIG. 10 is a cross-sectional view of a semiconductor film in a conventional semiconductor device.
  • FIG. 11 is a view schematically showing a conventional mask.
  • FIG. 12 is a view schematically showing a conventional laser light irradiation method.
  • FIG. 1 is a schematic cross-sectional view of a semiconductor device 5 of the present invention.
  • the semiconductor device 5 of the present invention has a basic structure in which the semiconductor film 3 is formed on the substrate 1, and preferably, the base insulating layer 2 is formed between the substrate 1 and the semiconductor film 3 as shown in FIG. Be intervened.
  • Base insulating layer 2 can be formed of a material such as silicon oxide or silicon nitride conventionally used in the art, for example, by the CVD method, and is not particularly limited. . Above all, it is preferable to form the base insulating layer 2 of silicon oxide since it is the same component as the glass substrate and various physical properties such as the thermal expansion coefficient are almost equal.
  • the thermal influence of the molten precursor semiconductor thin film is made to affect, for example, an insulating substrate such as a glass substrate mainly during melting and recrystallization by laser light.
  • insulating substrate force for example a glass substrate, can also prevent impurity diffusion into the precursor semiconductor thin film.
  • the thickness of the base insulating layer 2 is preferably about 50 to 200 nm, but is not limited thereto.
  • the base insulating film 2 can be formed on the substrate 1 by depositing the material by plasma enhanced chemical vapor deposition (PECVD), vapor deposition, sputtering, or the like.
  • the semiconductor film 3 in the semiconductor device 5 of the present invention is not particularly limited as long as it is a conventionally known one exhibiting semiconductor characteristics, but the crystal growth length is increased by lateral crystal growth by laser irradiation described later.
  • the force formed by using an amorphous silicon film which can significantly improve various properties by the above is preferable.
  • the semiconductor film 3 is not limited to a semiconductor film formed of an amorphous material such as amorphous silicon, but may be a crystalline semiconductor film such as microcrystalline or polycrystal.
  • the material of the semiconductor film 3 may be a material mainly composed of silicon containing other elements such as germanium, which is not limited to a material which can only exert silicon.
  • the semiconductor film 3 is formed by deposition such as plasma enhanced chemical vapor deposition (PECVD), catalytic chemical vapor deposition (Cat-CVD), vapor deposition, or sputtering so as to have a film thickness of 10 to: LOO nm. can do.
  • PECVD plasma enhanced chemical vapor deposition
  • Cat-CVD catalytic chemical vapor deposition
  • vapor deposition or sputtering so as to have a film thickness of 10 to: LOO nm. can do.
  • the semiconductor film 3 has a laterally grown crystal.
  • the lateral direction means a direction substantially parallel to the surface of the semiconductor film. That is, in the semiconductor film, the crystal growth direction mainly includes the plane direction of the semiconductor film and the thickness direction of the semiconductor film, and among these, the plane direction is meant.
  • the semiconductor device 5 of the present invention is characterized in that the surface projection height at the end of the laterally grown crystal of the semiconductor film 3 is lower than the film thickness of the semiconductor film.
  • the surface protrusion height refers to the maximum height of the protrusion at the end, and using AFM (atomic force microscope)
  • AFM atomic force microscope
  • the surface shape of the 20 um x 20 um region can be measured and calculated as an average value of the maximum height of 5 points or more.
  • the film thickness of the semiconductor film refers to the average thickness of the semiconductor film, which is formed as an area where the semiconductor film is formed using an atomic force microscope (AFM) or a stylus type profilometer. The level difference with the region can be measured and calculated.
  • AFM atomic force microscope
  • the TFT characteristics are improved compared to the prior art. is there. More specifically, it is effective to reduce the threshold voltage, to reduce the variation of the threshold voltage, and to reduce the subthreshold coefficient. Also, from the process point of view, the absence of protrusions at the end of the crystallization makes it possible to thin the film thickness of the gate oxide film, thereby improving throughput and TFT characteristics. Further improvement is possible.
  • FIG. 2A is a plan view of a semiconductor film crystal in the semiconductor device of the present invention
  • FIG. 2B is a cross-sectional view of the semiconductor film in the semiconductor device of the present invention
  • FIG. 10 is a cross-sectional view of the semiconductor film in the conventional semiconductor device.
  • the semiconductor device of the present invention for example, when the semiconductor film thickness is 50 nm, the surface protrusion height H at the end of the laterally grown crystals 11 and 12 is 30 nm (FIG. 2B).
  • the surface protrusion height H at the end of the laterally grown crystal 91, 92 of the conventional semiconductor device is 50 nm (FIG. 10).
  • the surface protrusion height H is reduced from the conventional 50 nm to 30 nm, which is lower than the thickness of the semiconductor film.
  • the height of the surface protrusions can be controlled by the mask pattern and the amount of energy can be further reduced, and the area other than the ridges is extremely flat and has few irregularities, specifically, few protrusions of 10 nm or more. And crystals can also be obtained.
  • the semiconductor device of the present invention is not particularly limited as long as the surface protrusion height is smaller than the film thickness of the semiconductor film, but the gate oxide film formed on the semiconductor film is not limited. Since the film thickness is about 100 nm and there is a possibility that current will leak and it will not operate as a TFT if the gate oxide film is pierced, the difference between the surface protrusion height and the film thickness of the semiconductor film is 150 nm or less. Is preferred. Moreover, if the film thickness of the gate oxide film is not constant, the threshold voltage may vary, and the surface protrusion height is required so as not to change the film thickness of the gate oxide film. The difference between the height of the protrusions and the thickness of the semiconductor film is more preferably 100 nm or less.
  • the threshold voltage is in inverse proportion to the thickness of the gate oxide film
  • the gate oxide film is in the direction in which the thin film is deposited, and for this purpose, the height of the surface protrusion needs to be as low as possible. From the viewpoint of this, it is particularly preferable that the difference between the height of the surface protrusions and the film thickness of the semiconductor film is 50 nm or less.
  • the semiconductor device of the present invention is not limited to one manufactured by the method of manufacturing a semiconductor device of the present invention as long as it has the above-mentioned features.
  • a step of irradiating a semiconductor film formed on a substrate with a laser to grow crystals laterally in the semiconductor film, and performing the crystal growth in the lateral direction are performed. Irradiating a laser of lower energy to make the surface protrusion height at the end of the laterally grown crystal lower than the film thickness of the semiconductor film.
  • the first step of the method of manufacturing a semiconductor device of the present invention first, a semiconductor film formed on a substrate by irradiating a semiconductor film with a laser using the SLS method which is a conventionally known method. Form laterally grown crystals.
  • the crystal growth direction mainly includes the plane direction of the semiconductor film and the thickness direction of the semiconductor film, and the “lateral direction” refers to the plane direction among them as described above.
  • the laser irradiation for crystal growth in the lateral direction be performed stepwise so as to take over the portion of the semiconductor film on which the crystal is grown.
  • “perform laser irradiation in a stepwise manner” means that the next laser pulse is irradiated so as to inherit the lateral crystal growth generated by one laser pulse, and the crystal growth generated by the laser pulse is inherited. It refers to irradiating the next laser pulse.
  • by performing laser irradiation stepwise it is possible to take over the form of the crystal generated by the first laser irradiation, so that a single crystal can be formed.
  • the ridge formed by the previous laser pulse irradiation can be removed by the next laser pulse irradiation.
  • the ridge formed by the previous laser pulse irradiation can be removed by the next laser pulse irradiation.
  • the subsequent step a laser having a lower energy than that of the laterally grown crystal is irradiated to make the surface protrusion height at the end of the laterally grown crystal lower than the film thickness of the semiconductor film. .
  • the height of the surface protrusions is generated at the end of the crystal growth, as described above.
  • the height of such surface protrusions can be made lower than the semiconductor film thickness. That is, in the method of manufacturing a semiconductor device of the present invention, the semiconductor film can not be completely melted in the entire film thickness direction by laser irradiation with low energy, and only the upper portion of the film is partially melted. As a result, many crystal nuclei are generated at the solid-liquid interface, and microcrystalline growth occurs in the film toward the lower surface. By thus recrystallizing by a mechanism different from that in the lateral direction, the height of surface protrusions can be made sufficiently low. Also, as described later, this is characterized in that the advantage of using a laser having a large absorption coefficient in a semiconductor film is further utilized.
  • irradiation of the laser with energy lower than that of the laterally crystal-grown laser is used as in any one of the following (1) to (3): And more preferred. (1) Used in final irradiation when laser irradiation is performed stepwise on a semiconductor device
  • the semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
  • the laser irradiation of a lower energy than that of the laterally crystal-grown laser is used in (1) final irradiation in stepwise laser irradiation of a semiconductor device, thereby achieving the final crystal growth in the lateral direction.
  • the time of irradiation only the upper part of the film is partially melted, many crystal nuclei are generated at the solid-liquid interface, and recrystallization is performed by a mechanism different from the lateral direction in the film, so that the surface protrusion height is sufficiently low. can do.
  • the laser irradiation with energy lower than that of the laterally crystal-grown laser is used, and (2) the final irradiation power in the case of stepwise laser irradiation on the semiconductor device is used rather than the irradiation before the step.
  • the final irradiation power is also several stages before the laser irradiation, and it is preferable to also irradiate the stage power two to three stages before the final irradiation, but it is not limited to these. In order to achieve the purpose of making the surface projection height lower than the film thickness by using it, it is preferable to design appropriately.
  • the laser irradiation with energy lower than that of the laser crystal grown in the lateral direction is used at the position of the final irradiation when the laser irradiation is performed stepwise on the semiconductor device. It is possible to reduce the protrusion only at the ridge that has no influence on the
  • FIGS. 3A to 3D are diagrams schematically showing masks preferably used in the method for manufacturing a semiconductor device of the present invention.
  • FIG. 11 is a view schematically showing a conventional mask.
  • a thin pattern 31 (FIG. 3A) or Preferably, the energy dose is controlled using a mask having slits or patterns 32 (FIG. 3B), 33 (FIG. 3C), 34 (FIG. 3D) below the diffraction limit.
  • the diffraction limit is determined by the wavelength of the excimer laser and the optical system, and is generally given by ⁇ , which is about 1 to 3 ⁇ m.
  • the pattern below the diffraction limit has a shape of about 2 um or less, for example, in the case of an apparatus having an excimer laser having a diffraction limit of about 3 um and an optical system. If it becomes smaller than the diffraction limit, the amount of transmitted light decreases and the energy decreases, so if it is too small, the effect may be lost. From this point of view, the diffraction limited 1Z 4 to 3Z 4 sizes are preferable.
  • the projection can be deformed into a desired shape by well combining the fine pattern and the pattern below the diffraction limit in comparison with the conventional slit pattern. It is possible.
  • a semiconductor film is irradiated with a laser to grow a crystal in the lateral direction using the SLS method, crystallization is performed so that the scanning direction of the stage and the lateral growth direction of the crystal are almost perpendicular.
  • the center line of the mask area having slits or patterns below or equal to the diffraction limit of light is colinear with the center line of the immediately preceding mask area.
  • a slit or pattern below the diffraction limit of the light may have back and forth (FIG. 4A) or a slit pattern according to the position of the final irradiation.
  • FIG. 4A use a mask that has a fine pattern or a pattern below the diffraction limit by switching back and forth (Fig. 4B).
  • FIG. 4A in the case of having a pattern in front and back, since light passing through a mask below the diffraction limit is irradiated before transverse crystallization, there is an effect that unevenness can be further reduced.
  • FIG. 12 schematically shows an example of conventional laser light irradiation as a comparison.
  • the laser beam used in the method for producing a semiconductor film of the present invention preferably has a large absorption coefficient in the semiconductor film so as not to affect the substrate. More specifically, it is preferable to have a wavelength in the ultraviolet range. For example, an excimer laser pulse having a wavelength of 308 nm can be mentioned.
  • the excimer laser necessary for the SLS method The energy content of is 2 to 8 kj / m 2 .
  • the energy amount of the excimer laser at the time of irradiation of a laser with a lower energy than that of the laterally crystal-grown laser is 0.5 to 4 kjZm 2 .
  • the laser beam used in the method for producing a semiconductor thin film of the present invention is an amount of energy per irradiation area for melting the semiconductor film in a solid state per one irradiation, specifically a semiconductor film. It is preferable to have an amount of energy that can be heated to a temperature above the melting point in the entire film thickness.
  • the amount of energy varies depending on the type of the material of the semiconductor film, the film thickness of the semiconductor film, the area of the crystallization region, etc. and can not be uniquely determined. Therefore, use laser light having an appropriate energy amount as appropriate. Hoped.
  • FIG. 5 is a diagram conceptually showing an example of an apparatus that can be used for the method of manufacturing a semiconductor device of the present invention described above.
  • the example device shown in FIG. It includes an exciter 42, a variable attenuator 43, a field lens 44, a mask 45, an imaging lens 46, a sample stage 47 and several mirrors, as well as uniform illumination optics. These members are controlled by the controller 41.
  • a radiation pulse can be supplied to the semiconductor device 5 on the stage 47.
  • laser energy can be attenuated by using a mask having a slit or a pattern below the diffraction limit of light as the mask 45 with respect to the laser light irradiated to the ridge.
  • a mask having a slit or a pattern below the diffraction limit of light as the mask 45 with respect to the laser light irradiated to the ridge.
  • FIG. 6 is a view conceptually showing a preferable example of the semiconductor device manufacturing apparatus of the present invention.
  • the present invention is an apparatus suitably used for the method of manufacturing a semiconductor device of the present invention described above, which is a controller for controlling a first laser oscillator 52, a second laser oscillator 58, and these two laser oscillators. And an apparatus for producing a semiconductor device.
  • the laser by the first laser oscillator 52 is used for irradiation for lateral crystal growth of the semiconductor film, and the second laser oscillator is used.
  • the laser according to 58 is used as an assist laser for suppressing the temperature drop of the melted semiconductor film.
  • the wavelength of the laser (first laser beam) generated from the first laser oscillator is a wavelength at which the semiconductor film (semiconductor film in the solid state) is easily absorbed. It is preferable that the wavelength of the laser (second laser beam) generated by the second laser oscillator is a wavelength that is easily absorbed by the substrate or the semiconductor film in a molten state.
  • a first laser beam for example, an excimer laser pulse having a wavelength of 308 nm can be mentioned.
  • the second laser light a YAG laser with a wavelength of 532 nm, a YAG laser with a wavelength of 10 64 nm, a carbon dioxide gas laser with a wavelength of 10.6 m, etc. may be mentioned.
  • the total of the first and second laser light energy used in the apparatus for manufacturing a semiconductor film of the present invention is the amount of energy capable of melting the semiconductor film in a solid state per one irradiation, per irradiation area. It is preferable to have.
  • the first laser beam is per irradiated area
  • the amount of energy varies depending on the type of the material of the semiconductor film, the film thickness of the semiconductor film, the area of the crystallization region, and the like, and can not be uniquely determined. Therefore, in the above-described method of manufacturing a semiconductor device of the present invention It is desirable to adopt a laser beam having an appropriate amount of energy as appropriate in accordance with the mode to be applied.
  • the amount of energy of the first laser required for the SLS method is 1 to 5 kjZm 2 and the amount of energy of the second laser is 0.5 to 4 kj Zm 2 It is.
  • FIG. 7 is a graph showing an outline of the relationship between the irradiation time of the first laser beam and the second laser beam and the output (irradiance) in the semiconductor device manufacturing apparatus of the present invention.
  • the horizontal axis represents time (hour), and the vertical axis represents output (unit: WZm 2 ).
  • the graph of the first laser beam is indicated by reference numeral 61, and the graph of the second laser beam is indicated by reference numeral 62.
  • the second laser is realized to emit at high power between the times tl and t2, and to emit the other at low power.
  • tl ⁇ t2.
  • the relationship between the irradiation time of the first laser beam and the second laser beam and the output is not particularly limited to this relationship.
  • the time tl may be a positive value or a negative value. That is, the irradiation start time of the second laser beam may be before or after the irradiation start time of the first laser beam.
  • Such first laser light and The irradiation of the second laser beam is realized by being appropriately controlled by the controller 51.
  • the controller 51 conventionally known appropriate control means can be used without particular limitation.
  • FIGS. 3A to 3D show the force of a mask suitably used in the method of manufacturing a semiconductor device of the present invention.
  • a mask is also novel and is included in the present invention. . That is, according to the present invention, the semiconductor film formed on the substrate is irradiated with a laser so that the semiconductor film is laterally grown and the crystal is laterally grown, and the crystal is laterally grown lower than the laser!
  • an energy laser which is lower than the laterally grown crystal laser
  • a mask characterized by having a slit or pattern below the diffraction limit, which is used to perform laser irradiation of energy.
  • the present invention further provides a manufacturing apparatus provided with the above mask. That is, according to the present invention, a semiconductor film formed on a substrate is irradiated with a laser to grow crystals in the lateral direction in the semiconductor film, and a laser having energy lower than that of the laser grown in the lateral direction is irradiated. In the method of manufacturing a semiconductor device, in which the height of the surface protrusion at the end of the laterally grown crystal is made smaller than the film thickness of the semiconductor film, laser irradiation with energy lower than that of the laterally grown crystal is performed. Also provided is a manufacturing apparatus comprising a mask having a slit or pattern below the diffraction limit, which is used for

Abstract

A semiconductor device (5) having a semiconductor film (3) on a substrate (1) is characterized in that the semiconductor film (3) has a laterally-grown crystal and a height of a surface protrusion at an edge section of the laterally grown crystal is less than a thickness of the semiconductor film (3). A method and an apparatus for manufacturing the semiconductor device (5), by which the height of the surface protrusion (ridge) in a last region wherein laser irradiation is repeated by SLS method can be reduced, and the semiconductor device manufactured by the method and the apparatus are provided.

Description

明 細 書  Specification
半導体デバイス、その製造方法および製造装置  Semiconductor device, method of manufacturing the same, and manufacturing apparatus
技術分野  Technical field
[0001] 本発明は、レーザを用いて非晶質半導体材料を結晶化させた半導体デバイスおよ びその製造方法、製造装置に関するものである。  The present invention relates to a semiconductor device obtained by crystallizing an amorphous semiconductor material using a laser, a method of manufacturing the same, and a manufacturing apparatus.
背景技術  Background art
[0002] 薄膜材料の上に半導体デバイスを形成した薄膜トランジスタ (TFT)は、アクティブ マトリクス液晶表示装置における表示部ならびに画素コントローラなどに用いられて おり、薄膜材料としては非晶質材料が主に用いられている。さらに、 TFTを高速駆動 させるために、従来非晶質半導体膜が用いられて 、たチャネル領域を結晶化するこ とにより、材料特性を向上させることが行われている。これは結晶という原子配列のそ ろった部分におけるキャリアの移動度が、非晶質部分におけるそれより数百倍大きく なるためである。し力し多結晶の場合は、結晶粒界においてキャリアの散乱が生じる ため、より結晶粒を大きくしチャネル領域において単結晶となることが望まれる。  A thin film transistor (TFT) in which a semiconductor device is formed on a thin film material is used for a display unit and a pixel controller in an active matrix liquid crystal display device, and an amorphous material is mainly used as the thin film material. ing. Furthermore, in order to drive the TFT at high speed, conventionally, an amorphous semiconductor film is used, and the material characteristic is improved by crystallizing the channel region. This is because the mobility of carriers in the entire portion of the atomic arrangement of crystals is several hundred times greater than that in the amorphous portion. In the case of a polycrystal, carriers are scattered at grain boundaries, so it is desirable to make the grains larger and to be single crystals in the channel region.
[0003] 結晶化にはいくつかの方法が提案されている力 ノ ルスレーザを用いると短時間に 大きなエネルギを投入できるため、低温でのプロセスが可能となることから、開発が進 められている。その中で、結晶の横方向成長方法およびこれを利用する逐次横方向 結晶化方法（SLS : Sequential Lateral Solidification)と呼ばれる方法がある。  [0003] Several methods have been proposed for crystallization. Development is promoted because a low-temperature process is possible because a large amount of energy can be input in a short time by using a force pulse laser. . Among them, there is a method called lateral crystal growth and a method called sequential lateral crystallization (SLS) using it.
[0004] 横方向成長により形成された結晶を、図 8A〜図 8Bを用いて説明する。図 8A〜図 8Bは結晶の横方向成長法を用いて結晶化させた膜の正面図であり、図 8Aは小さい 幅のマスクを用いた場合の結晶であり、図 8Bは大き!/、幅のマスクを用いた場合の結 晶である。結晶の横方向成長法では、非晶質半導体膜にマスクを用いてレーザビー ムをパルス照射し、この領域を完全に溶融させる。その後冷却されることにより溶融し た半導体膜は再凝固するが、この際凝固しな力つた固体部との境界付近力も横方向 に結晶長さ L1の特有の結晶化が起こる。図 8Aに示すようにマスクの幅がある程度狭 いと、この横方向結晶 71, 72がパターンの中央部で衝突し、突起状の表面ラフネス（ 以下「リッジ」と呼ぶ）が形成される。これは、液体状のシリコンが凝固する際に体積が 増えることが原因であり、凝固することにより増えた体積の分だけ、上方へ突起が形 成される。図 8Bに示すようにマスクの幅がある程度広いと、横方向の結晶化が進む 途中でパターンの中央部付近力 も冷却が始まり、下方向から上方向への微結晶化 力 S起こる。これに横方向の結晶化は阻害されることとなり、リッジ 73を形成して止まる。 これらの横方向結晶 71, 72は、完全溶融した端からリッジ 73までの長さを持つ大き な一つの単結晶であり、この方向を TFTチャネル方向にとると、キャリアの流れに垂 直な粒界は存在しな!、ため良好な特性を得ることができる。 Crystals formed by lateral growth will be described using FIGS. 8A to 8B. 8A-8B are front views of a film crystallized using the lateral crystal growth method, FIG. 8A is a crystal when using a mask with a small width, and FIG. 8B is a size! / Width It is a crystal when using a mask of In the lateral crystal growth method, a laser beam is pulsed to the amorphous semiconductor film using a mask to completely melt this region. Thereafter, the melted semiconductor film is re-solidified by cooling, but at this time, a force near the boundary with the solidified solid portion also causes peculiar crystallization of the crystal length L1 in the lateral direction. As shown in FIG. 8A, when the width of the mask is narrow to some extent, the lateral crystals 71 and 72 collide at the central portion of the pattern to form a convex surface roughness (hereinafter referred to as “ridge”). This is because when the liquid silicon solidifies, The cause is the increase, and the protrusion is formed upward by the increased volume due to the solidification. As shown in FIG. 8B, when the width of the mask is wide to some extent, cooling in the middle of the pattern also begins along the way of crystallization in the lateral direction, and microcrystallization force S occurs from the bottom to the top. This will inhibit lateral crystallization and will stop forming ridges 73. These lateral crystals 71, 72 are large single crystals having a length from the completely melted end to the ridge 73, and when this direction is taken in the TFT channel direction, the grains are perpendicular to the carrier flow. There is no world !, so good characteristics can be obtained.
[0005] SLS法はさらに結晶長を伸ばすための方法であり、特表 2000— 505241号公報（ 特許文献 1)に示すように、この結晶を種として横方向結晶化を続けることができる。 sThe SLS method is a method for further extending the crystal length, and as shown in JP-A 2000-505241 (patent document 1), lateral crystallization can be continued using this crystal as a seed. s
LS法により形成された結晶を図 9A〜図 9Dを用いて説明する。図 9A〜図 9Dは、 S LS法を用いて結晶化させた膜の正面図である。まず、図 9Aのように矩形マスクゃレ 一ザに対してサンプル (非晶質半導体膜)を距離 L2だけ移動させ (シフトさせ)て、レ 一ザ照射することによって、シフトさせたレーザ照射部分 83が完全に溶融し再凝固 する。この際、図 9Bに示すように、一つ前の結晶粒を種として引き継ぐため、結晶長 さ L2 +結晶長さ L3の大きな単結晶を得ることができる。さらに、図 9Cおよび図 9Dに 示すように、このシフトとレーザ照射を繰り返すことによって、所望の長さの単結晶を 得ることができる。 The crystals formed by the LS method will be described with reference to FIGS. 9A to 9D. 9A-9D are front views of films crystallized using the S LS method. First, as shown in FIG. 9A, the laser irradiation portion is shifted by moving (shifting) the sample (amorphous semiconductor film) by a distance L2 with respect to the rectangular mask laser and irradiating the laser. 83 melts completely and resolidifies. At this time, as shown in FIG. 9B, since a single preceding crystal grain is taken over as a seed, a large single crystal of crystal length L 2 + crystal length L 3 can be obtained. Furthermore, as shown in FIGS. 9C and 9D, by repeating this shift and laser irradiation, a single crystal of a desired length can be obtained.
[0006] この際、サンプルを適当な量シフトさせることにより、横方向の結晶化において形成 される直前のリッジを消去することができる。発生したリッジをカバーする領域に次の レーザを照射させることによって、再度完全溶融するためこのリッジは消え、横方向結 晶成長した分だけ進んだ位置に新たなリッジが形成される。したがって、 TFTチヤネ ル部が形成される最終的な結晶領域には、リッジと呼ばれる突起状の表面ラフネス ( 表面突起高さ）は存在せず、フラットな表面が得られる。  At this time, by shifting the sample by an appropriate amount, it is possible to erase the ridge just before being formed in the lateral crystallization. By irradiating the area covering the generated ridge with the next laser, the ridge disappears because it completely melts again, and a new ridge is formed at a position advanced by the amount of lateral crystal growth. Therefore, in the final crystalline region where the TFT channel portion is formed, there is no protrusion-like surface roughness (surface protrusion height) called a ridge, and a flat surface is obtained.
[0007] し力しながら、上記 SLS法においても、レーザ照射を繰り返した最後の領域におけ るリッジは残るため、その後のデバイス作製プロセスにとって問題となる。たとえば、半 導体膜のリッジ部を含む領域上に、ゲート部、コンタクト部ほかの膜を堆積する場合、 膜厚が制限となるだけでなぐ特性が劣化する可能性が大きぐさらには将来的な微 細化の観点からも障害となる。 [0008] このような SLS法の最後の領域におけるリッジ高さを低減させるため、たとえば特表 2003— 509845号公報 (特許文献 2)には、減衰器を用いたレーザビーム強度変調 が提案されている。特許文献 2に記載されたレーザビーム強度変調を適用すると、半 導体膜を部分的に溶融させるため横方向結晶化が起こらず、リッジを消去することが できる。しかし、そのためには、減衰器やその駆動システムなど、新たな機器が必要と なる。またレーザの照射周波数が高い生産システムにおいては、これらの減衰器を高 速に動作させる必要があり、その実現は困難なものとなる。 However, in the above-mentioned SLS method, the ridge in the last region where the laser irradiation is repeated remains, which poses a problem for the subsequent device fabrication process. For example, in the case where a film such as a gate portion or a contact portion is deposited on a region including a ridge portion of a semiconductor film, the film thickness is limited, and the possibility of degradation of the characteristics is further increased. It is also an obstacle in terms of micronization. In order to reduce the ridge height in the last region of such an SLS method, for example, a laser beam intensity modulation using an attenuator is proposed in Japanese Patent Application Laid-Open No. 2003-509845 (Patent Document 2). There is. When the laser beam intensity modulation described in Patent Document 2 is applied, lateral crystallization does not occur because the semiconductor film is partially melted, and the ridge can be erased. However, new equipment such as attenuators and their drive systems will be needed for that purpose. Moreover, in a production system where the laser irradiation frequency is high, these attenuators need to be operated at high speed, which is difficult to realize.
[0009] また特開 2003— 309080号公報（特許文献 3)には、 SLS法により結晶化した領域 におけるリッジ高さを低減させるため、回折限界以下のマスクを通過した光を照射す る手法が記載されている。し力しながら、この方法では、結晶化した全領域に光が照 射されるため、突起は減少するが表面の凹凸が大きくなり TFTの特性の低下を招く 危険性がある。また結晶化の方向を一方向に限定する必要がある。  In addition, Japanese Patent Application Laid-Open No. 2003-309080 (Patent Document 3) discloses a method for irradiating light passing through a mask below the diffraction limit in order to reduce the height of the ridge in the region crystallized by the SLS method. Have been described. In this method, light is irradiated to the entire crystallized region, so that the protrusions are reduced but the surface irregularities become large, which may cause deterioration of the TFT characteristics. In addition, it is necessary to limit the direction of crystallization to one direction.
特許文献 1：特表 2000— 505241号公報  Patent Document 1: JP 2000-505241
特許文献 2：特表 2003 - 509845号公報  Patent Document 2: Japanese Patent Application Publication No. 2003-509845
特許文献 3：特開 2003 - 309080号公報  Patent Document 3: Japanese Patent Application Laid-Open No. 2003-309080
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problem that invention tries to solve
[0010] 本発明は、上記課題を解決するためになされたものであって、 SLS法においてレー ザ照射を繰り返した最後の領域における表面突起高さ（リッジ)を低減させることがで きる新規な半導体デバイスの製造方法、製造装置およびそれらによって製造された 半導体デバイスを提供することを目的とする。 The present invention has been made to solve the above problems, and is a novel method capable of reducing the surface protrusion height (ridge) in the last region where laser irradiation is repeated in the SLS method. An object of the present invention is to provide a method of manufacturing a semiconductor device, a manufacturing apparatus, and a semiconductor device manufactured by them.
課題を解決するための手段  Means to solve the problem
[0011] 本発明の半導体デバイスは、基板上に半導体膜が形成されてなる基本構造を備えThe semiconductor device of the present invention has a basic structure in which a semiconductor film is formed on a substrate.
、該半導体膜は横方向成長結晶を有し、かつ、該横方向成長結晶の端部において 表面突起高さが前記半導体膜の膜厚より低いことを特徴とする。 The semiconductor film is characterized in that it has a laterally grown crystal, and the height of the surface protrusion is smaller than the thickness of the semiconductor film at the end of the laterally grown crystal.
[0012] ここにおいて、前記横方向成長結晶は、前記半導体膜にレーザ照射することにより 結晶成長された結晶であることが好ま 、。  Here, the laterally grown crystal is preferably a crystal grown by laser irradiation to the semiconductor film.
[0013] さらに、前記横方向成長結晶は、前記レーザ照射を、レーザ照射により横方向に結 晶成長した部分を引き継ぐように半導体膜の面方向に段階的に移動して、前記部分 の結晶を引き継ぐことにより、結晶成長が拡大された領域であることが好ましい。 [0013] Furthermore, the laterally grown crystal is laterally bonded to the laser irradiation by the laser irradiation. It is preferable that the region is a region where crystal growth is expanded by moving stepwise in the surface direction of the semiconductor film so as to inherit the crystal-grown portion and inheriting the crystal of the portion.
[0014] また、本発明の半導体デバイスは、横方向結晶成長の端部における表面突起高さ 力 回折限界以下のスリットもしくはパターンを通過した光を利用することにより、前記 横方向成長結晶を形成するための前記レーザのエネルギよりも低いエネルギを有す るレーザを照射することにより、半導体膜の膜厚よりも低くされたものであることが好ま しい。  In the semiconductor device of the present invention, the laterally grown crystal is formed by utilizing light having passed through a slit or pattern below the diffraction limit of the surface protrusion height force at the end of the transverse crystal growth. It is preferable that the film thickness of the semiconductor film be made lower by irradiating a laser having an energy lower than that of the above-mentioned laser.
[0015] さらに、本発明の半導体デバイスは、前記前記横方向成長結晶を形成するための 前記レーザのエネルギよりも低いエネルギを有するレーザを、以下の（1)〜（3)のい ずれかのように用いて作製されたものであるの力 より好まし!/、。  Furthermore, a semiconductor device according to the present invention is characterized in that the laser having energy lower than that of the laser for forming the laterally grown crystal is any one of the following (1) to (3): The power of being produced by using is more preferable!
(1)半導体デバイスに段階的にレーザ照射する際の最終照射において用いる、 (1) Used in final irradiation when laser irradiation is performed stepwise on a semiconductor device
(2)半導体デバイスに段階的にレーザ照射する際の最終照射から数段階前の照射 より用いる、 (2) A few steps prior to the final irradiation when laser irradiation is performed stepwise on a semiconductor device
(3)半導体デバイスに段階的にレーザ照射する際の最終照射の位置において用い る。  (3) The semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
[0016] また本発明は、基板上に形成された半導体膜にレーザを照射して該半導体膜にお いて横方向に結晶成長させるステップと、前記横方向に結晶成長させたレーザより低 いエネルギのレーザを照射して前記横方向の成長結晶の端部における表面突起高 さを前記半導体膜の膜厚よりも低くするステップとを含む、半導体デバイスの製造方 法を提供する。  Further, according to the present invention, a step of irradiating a semiconductor film formed on a substrate with a laser to grow crystals laterally in the semiconductor film, and energy lower than the laser grown the crystals in the lateral direction And irradiating the surface of the lateral growth crystal with a height smaller than the thickness of the semiconductor film.
[0017] 本発明の半導体デバイスの製造方法においては、前記半導体膜において横方向 に結晶成長させるレーザ照射を、結晶成長した半導体膜の部分を引き継ぐように段 階的に移動させて行うことが、好ましい。  In the method of manufacturing a semiconductor device according to the present invention, laser irradiation for crystal growth in the lateral direction in the semiconductor film may be performed by stepwise moving so as to take over a portion of the semiconductor film on which crystal growth has been performed. preferable.
[0018] 本発明の半導体デバイスの製造方法においても、前記前記横方向成長結晶を形 成するための前記レーザのエネルギよりも低いエネルギを有するレーザを、以下の（Also in the method of manufacturing a semiconductor device according to the present invention, a laser having energy lower than that of the laser for forming the laterally grown crystal is
1)〜（3)の!、ずれかのように用いること力 より好まし!/、。 1) ~ (3) !, the ability to use as if you prefer!
(1)半導体デバイスに段階的にレーザ照射する際の最終照射において用いる、 (1) Used in final irradiation when laser irradiation is performed stepwise on a semiconductor device
(2)半導体デバイスに段階的にレーザ照射する際の最終照射から数段階前の照射 より用いる、 (2) Irradiation several steps prior to final irradiation when laser irradiation is performed stepwise on semiconductor devices Use more
(3)半導体デバイスに段階的にレーザ照射する際の最終照射の位置において用い る。  (3) The semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
[0019] さらに、本発明の半導体デバイスの製造方法においては、前記横方向に結晶成長 させたレーザより低 、エネルギのレーザ照射を行うために、回折限界以下のスリットも しくはパターンを有するマスクを利用してエネルギ照射量を制御することが、好ま ヽ  Furthermore, in the method of manufacturing a semiconductor device according to the present invention, a mask having a slit or pattern below the diffraction limit is used to perform laser irradiation with energy lower than that of the laser crystal grown in the lateral direction. It is preferred to control the energy dose by using
[0020] また、本発明は、上述した本発明の半導体デバイスの製造方法に好適に用いられ る半導体デバイス製造装置も提供する。カゝかる本発明の半導体デバイスの製造装置 は、第一のレーザ発振器と、第二のレーザ発振器と、これら 2つのレーザ発振器を制 御するコントローラとを含むことを特徴とする。 The present invention also provides a semiconductor device manufacturing apparatus suitably used for the above-described method of manufacturing a semiconductor device of the present invention. The semiconductor device manufacturing apparatus of the present invention is characterized by including a first laser oscillator, a second laser oscillator, and a controller for controlling these two laser oscillators.
[0021] 力かる本発明の半導体デバイス製造装置において、第二のレーザ発振器から発生 するレーザのエネルギは、第一のレーザ発振器力 発生するレーザのエネルギよりも 低いことが好ましい。  Preferably, in the semiconductor device manufacturing apparatus of the present invention, the energy of the laser generated from the second laser oscillator is lower than the energy of the laser generated by the first laser oscillator.
[0022] また、第一のレーザ発振器から発生するレーザの波長が、半導体膜に吸収されや すい波長であり、第二のレーザ発振器力 発生するレーザの波長が、基板または溶 融状態の半導体膜に吸収されやすい波長であることがより好ましい。  Further, the wavelength of the laser generated from the first laser oscillator is a wavelength which is easily absorbed by the semiconductor film, and the wavelength of the laser generated by the second laser oscillator is a substrate or a semiconductor film in a melted state. It is more preferable that the wavelength is easily absorbed by
[0023] また、本発明は、基板上に形成された半導体膜にレーザを照射して該半導体膜に ぉ ヽて横方向に結晶成長させ、前記横方向に結晶成長させたレーザより低 、エネル ギのレーザを照射して前記横方向の成長結晶の端部における表面突起高さを前記 半導体膜の膜厚よりも低くする半導体デバイスの製造方法において、横方向に結晶 成長させたレーザより低 、エネルギのレーザ照射を行うために用いられる、回折限界 以下のスリットもしくはパターンを有することを特徴とするマスクも提供する。  Further, according to the present invention, the semiconductor film formed on the substrate is irradiated with a laser to cause the semiconductor film to grow laterally and to grow crystals laterally, which is lower than the laser which is caused to grow crystals laterally. In the method of manufacturing a semiconductor device in which the height of the surface protrusion at the end of the laterally grown crystal is made smaller than the film thickness of the semiconductor film by irradiating a laser of Also provided is a mask, characterized in that it has slits or patterns below the diffraction limit, which are used for the laser irradiation of energy.
[0024] 本発明はさらに、基板上に形成された半導体膜にレーザを照射して該半導体膜に ぉ ヽて横方向に結晶成長させ、前記横方向に結晶成長させたレーザより低 、エネル ギのレーザを照射して前記横方向の成長結晶の端部における表面突起高さを前記 半導体膜の膜厚よりも低くする半導体デバイスの製造方法において、横方向に結晶 成長させたレーザより低 、エネルギのレーザ照射を行うために用いられる、回折限界 以下のスリットもしくはパターンを有するマスクを備えることを特徴とする製造装置をも 提供する。 Further, according to the present invention, a semiconductor film formed on a substrate is irradiated with a laser, and the semiconductor film is laterally grown by laterally growing crystals, and energy is lower than that of the laser grown by laterally growing crystals. In the method of manufacturing a semiconductor device in which the height of the surface protrusion at the end of the laterally grown crystal is made smaller than the film thickness of the semiconductor film by irradiating the laser of Diffraction limit used to perform laser irradiation of Also provided is a manufacturing apparatus comprising a mask having the following slits or patterns.
発明の効果  Effect of the invention
[0025] 本発明の半導体デバイスの製造方法、マスクおよび半導体デバイスの製造装置に よって、従来とは異なり、減衰器やその駆動システムなどの機器を要することがなぐ また、表面の凹凸が大きくなるようなこともなぐ結晶化の端部における表面突起高さ が半導体膜の膜厚より低い半導体デバイスを提供することができる。このような半導 体デバイスによれば、従来と比較して、 TFT特性が改善されるという効果がある。より 具体的には、閾値電圧の低減、閾値電圧のばらつきの低減、サブスレショルド係数 の低減に効果がある。また、プロセス上の観点力もも、結晶化の端部における突起が なくなることで、ゲート酸ィ匕膜の膜厚を薄膜ィ匕することが可能になり、スループットの 改善と TFT特性のさらなる改善が可能になる。  According to the method of manufacturing a semiconductor device, the mask, and the apparatus for manufacturing a semiconductor device of the present invention, it is not necessary to require an apparatus such as an attenuator or a driving system thereof unlike the prior art. It is possible to provide a semiconductor device in which the height of the surface protrusions at the end of crystallization which is not so serious is smaller than the thickness of the semiconductor film. Such a semiconductor device has an effect of improving the TFT characteristics as compared with the conventional one. More specifically, it is effective in reducing the threshold voltage, reducing the variation in threshold voltage, and reducing the subthreshold coefficient. In addition, process point of view also makes it possible to thin the film thickness of the gate oxide film by eliminating the protrusion at the end of crystallization, which improves throughput and further improves TFT characteristics. It will be possible.
図面の簡単な説明  Brief description of the drawings
[0026] [図 1]本発明の半導体デバイスの概略断面図である。 FIG. 1 is a schematic cross-sectional view of a semiconductor device of the present invention.
[図 2A]本発明の半導体デバイスにおける半導体膜結晶の平面図である。  FIG. 2A is a plan view of a semiconductor film crystal in the semiconductor device of the present invention.
[図 2B]本発明の半導体デバイスにおける半導体膜の断面図である。  FIG. 2B is a cross-sectional view of the semiconductor film in the semiconductor device of the present invention.
[図 3A]本発明の半導体デバイスの製造方法において好適に用いられるマスクを模式 的に示す図である。  FIG. 3A is a view schematically showing a mask preferably used in the method of manufacturing a semiconductor device of the present invention.
[図 3B]本発明の半導体デバイスの製造方法において好適に用いられるマスクを模式 的に示す図である。  FIG. 3B is a view schematically showing a mask preferably used in the method of manufacturing a semiconductor device of the present invention.
[図 3C]本発明の半導体デバイスの製造方法において好適に用いられるマスクを模式 的に示す図である。  FIG. 3C is a view schematically showing a mask suitably used in the method of manufacturing a semiconductor device of the present invention.
[図 3D]本発明の半導体デバイスの製造方法にお!、て好適に用 、られるマスクを模式 的に示す図である。  FIG. 3D is a view schematically showing a mask suitably used for the method for manufacturing a semiconductor device of the present invention.
[図 4A]本発明の半導体デバイスの製造方法における好適なレーザ光の照射方法を 模式的に示す図である。  FIG. 4A is a view schematically showing a suitable laser light irradiation method in the method of manufacturing a semiconductor device of the present invention.
[図 4B]本発明の半導体デバイスの製造方法における好適なレーザ光の照射方法を 模式的に示す図である。 [図 5]本発明の半導体デバイスの製造方法に用いることができる装置の一例を概念 的に示す図である。 FIG. 4B is a view schematically showing a suitable laser light irradiation method in the method of manufacturing a semiconductor device of the present invention. FIG. 5 is a diagram conceptually showing an example of an apparatus that can be used in the method of manufacturing a semiconductor device of the present invention.
[図 6]本発明の半導体デバイスの製造装置を好ましい一例を概念的に示す図である  [FIG. 6] A diagram conceptually showing a preferred example of a semiconductor device manufacturing apparatus of the present invention.
[図 7]本発明の半導体デバイスの製造装置における、第一のレーザ光および第二の レーザ光の照射時刻と出力 (放射照度)との関係の概要を説明するグラフである。 FIG. 7 is a graph illustrating an outline of a relationship between irradiation time and output (irradiance) of the first laser beam and the second laser beam in the semiconductor device manufacturing apparatus of the present invention.
[図 8A]結晶の横方向成長法を用いて結晶化させた膜の平面図である。  FIG. 8A is a plan view of a film crystallized using a lateral crystal growth method.
[図 8B]結晶の横方向成長法を用いて結晶化させた膜の平面図である。  FIG. 8B is a plan view of a film crystallized using a crystal lateral growth method.
[図 9A]SLS法を用いて結晶化させた膜の平面図である。  FIG. 9A is a plan view of a film crystallized using SLS method.
[図 9B]SLS法を用いて結晶化させた膜の平面図である。  FIG. 9B is a plan view of a film crystallized using SLS method.
[図 9C]SLS法を用いて結晶化させた膜の平面図である。  FIG. 9C is a plan view of a film crystallized using SLS method.
[図 9D]SLS法を用いて結晶化させた膜の平面図である。  FIG. 9D is a plan view of a film crystallized using an SLS method.
[図 10]従来の半導体デバイスにおける半導体膜の断面図である。  FIG. 10 is a cross-sectional view of a semiconductor film in a conventional semiconductor device.
[図 11]従来のマスクを模式的に示す図である。  FIG. 11 is a view schematically showing a conventional mask.
[図 12]従来のレーザ光の照射方法を模式的に示す図である。  FIG. 12 is a view schematically showing a conventional laser light irradiation method.
符号の説明  Explanation of sign
[0027] 1 基板、 2 下地絶縁膜、 3 半導体膜、 5 半導体デバイス、 31, 32, 33, 34 マ スク、 41, 51 コントローラ、 43, 53 可変減衰器、 44, 54 フィールドレンズ、 45, 5 5 マスク、 46, 56 結像レンズ、 47, 57 サンプルステージ、 42, 52 第一のレーザ 発振器、 58 第二のレーザ発振器、 71, 81 結晶成長長さ、 82 距離、 83 レーザ 照射部分。  [0027] 1 substrate, 2 base insulating film, 3 semiconductor films, 5 semiconductor devices, 31, 32, 33, 34 masks, 41, 51 controllers, 43, 53 variable attenuators, 44, 54 field lenses, 45, 5 5 mask, 46, 56 imaging lens, 47, 57 sample stage, 42, 52 first laser oscillator, 58 second laser oscillator, 71, 81 crystal growth length, 82 distance, 83 laser irradiated part.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0028] 図 1は、本発明の半導体デバイス 5の概略断面図である。本発明の半導体デバイス 5は、基板 1上に半導体膜 3が形成されてなる基本構造を備え、好ましくは、図 1に示 すように基板 1と半導体膜 3との間に下地絶縁層 2が介在される。  FIG. 1 is a schematic cross-sectional view of a semiconductor device 5 of the present invention. The semiconductor device 5 of the present invention has a basic structure in which the semiconductor film 3 is formed on the substrate 1, and preferably, the base insulating layer 2 is formed between the substrate 1 and the semiconductor film 3 as shown in FIG. Be intervened.
[0029] 本発明の半導体デバイス 5における基板 1としては、絶縁性のものを用いることが好 ましぐガラス基板や石英基板等を用いることができるが、安価である点および大面 積の基板を容易に製造できる点でガラス基板を用いることが好適である。 [0030] 下地絶縁層 2は、当分野で従来より用いられている酸ィ匕シリコン、窒化シリコンなど の材料にてたとえば CVD法などにて形成することができ、特に制限されるものではな い。中でもガラス基板と同一成分であり、熱膨張係数などの各種物性がほぼ等しいこ とから、酸ィ匕シリコンにて下地絶縁層 2を形成するのが好ましい。下地絶縁層 2を形成 することにより、主としてレーザ光による溶融、再結晶化の際に、溶融した前駆体半導 体薄膜の熱影響がたとえばガラス基板である絶縁性基板に及ばな ヽようにすることが でき、さらにたとえばガラス基板である絶縁性基板力も前駆体半導体薄膜への不純 物拡散を防止することができる。なお下地絶縁層 2の厚みは、 50〜200nm程度にす ることが好ましいが、これに限定されるわけではない。当該下地絶縁膜 2は、上記材 料をプラズマェンハンスドィ匕学気相堆積 (PECVD)、蒸着、またはスパッタリングなど により堆積して上記基板 1上に形成することができる。 As the substrate 1 in the semiconductor device 5 of the present invention, it is preferable to use an insulating substrate, such as a glass substrate or a quartz substrate, but it is preferable to use an inexpensive and large-area substrate. It is preferable to use a glass substrate because it can be easily manufactured. Base insulating layer 2 can be formed of a material such as silicon oxide or silicon nitride conventionally used in the art, for example, by the CVD method, and is not particularly limited. . Above all, it is preferable to form the base insulating layer 2 of silicon oxide since it is the same component as the glass substrate and various physical properties such as the thermal expansion coefficient are almost equal. By forming base insulating layer 2, the thermal influence of the molten precursor semiconductor thin film is made to affect, for example, an insulating substrate such as a glass substrate mainly during melting and recrystallization by laser light. In addition, insulating substrate force, for example a glass substrate, can also prevent impurity diffusion into the precursor semiconductor thin film. The thickness of the base insulating layer 2 is preferably about 50 to 200 nm, but is not limited thereto. The base insulating film 2 can be formed on the substrate 1 by depositing the material by plasma enhanced chemical vapor deposition (PECVD), vapor deposition, sputtering, or the like.
[0031] 本発明の半導体デバイス 5における半導体膜 3は、半導体特性を示す従来公知の ものであれば特に制限されないが、後述するレーザ照射による横方向結晶成長で結 晶成長長さを長くすることによって種々の特性が顕著に向上するアモルファスシリコ ン膜を用いて形成されるの力 好ましい。しかし、半導体膜 3は、アモルファスシリコン のように非晶質のもので形成された半導体膜に限らず、微結晶や多結晶などの結晶 性半導体膜であってもよい。また半導体膜 3の材質は、シリコンのみ力もなる材質に 限られるものではなぐゲルマニウムなどの他の元素を含んだシリコンを主成分とする 材質であってもよい。半導体膜 3は、膜厚が 10〜： LOOnmとなるように、プラズマェン ハンスド化学気相堆積 (PECVD)、触媒化学気相堆積 (Cat— CVD)、蒸着、または スパッタリングなどにより堆積させることで、形成することができる。  The semiconductor film 3 in the semiconductor device 5 of the present invention is not particularly limited as long as it is a conventionally known one exhibiting semiconductor characteristics, but the crystal growth length is increased by lateral crystal growth by laser irradiation described later. The force formed by using an amorphous silicon film which can significantly improve various properties by the above is preferable. However, the semiconductor film 3 is not limited to a semiconductor film formed of an amorphous material such as amorphous silicon, but may be a crystalline semiconductor film such as microcrystalline or polycrystal. Further, the material of the semiconductor film 3 may be a material mainly composed of silicon containing other elements such as germanium, which is not limited to a material which can only exert silicon. The semiconductor film 3 is formed by deposition such as plasma enhanced chemical vapor deposition (PECVD), catalytic chemical vapor deposition (Cat-CVD), vapor deposition, or sputtering so as to have a film thickness of 10 to: LOO nm. can do.
[0032] 本発明の半導体デバイス 5は、上記半導体膜 3が横方向成長結晶を有する。ここで 、横方向とは、半導体膜の面と実質的に平行な方向をいう。すなわち、半導体膜に おいて、結晶成長する方向としては、主として、半導体膜の面方向と、半導体膜の厚 さ方向とが挙げられるが、このうち、面方向のことを意味する。  In the semiconductor device 5 of the present invention, the semiconductor film 3 has a laterally grown crystal. Here, the lateral direction means a direction substantially parallel to the surface of the semiconductor film. That is, in the semiconductor film, the crystal growth direction mainly includes the plane direction of the semiconductor film and the thickness direction of the semiconductor film, and among these, the plane direction is meant.
[0033] 本発明の半導体デバイス 5は、この半導体膜 3の横方向成長結晶の端部における 表面突起高さが、半導体膜の膜厚よりも低いことを特徴とするものである。ここで、上 記表面突起高さは、端部の突起の最大高さを指し、 AFM (原子間力顕微鏡)を用い て 20um X 20um領域の表面形状を測定し、その最大高さ 5点以上の平均値として 算出することができる。また、上記半導体膜の膜厚は、半導体膜の平均厚みを指し、 AFM (原子間力顕微鏡)または触針式の段差計を用いて半導体膜が形成されて!ヽ る領域と形成されて 、な 、領域との段差を測定して算出することができる。このように 半導体膜 3の横方向成長結晶の端部における表面突起高さが、半導体膜の膜厚より も低い半導体デバイスによれば、従来と比較して、 TFT特性が改善されるという効果 がある。より具体的には、閾値電圧の低減、閾値電圧のばらつきの低減、サブスレシ ョルド係数の低減に効果がある。また、プロセス上の観点からも、結晶化の端部にお ける突起がなくなることで、ゲート酸ィ匕膜の膜厚を薄膜ィ匕することが可能になり、スル 一プットの改善と TFT特性のさらなる改善が可能になる。 The semiconductor device 5 of the present invention is characterized in that the surface projection height at the end of the laterally grown crystal of the semiconductor film 3 is lower than the film thickness of the semiconductor film. Here, the surface protrusion height refers to the maximum height of the protrusion at the end, and using AFM (atomic force microscope) The surface shape of the 20 um x 20 um region can be measured and calculated as an average value of the maximum height of 5 points or more. In addition, the film thickness of the semiconductor film refers to the average thickness of the semiconductor film, which is formed as an area where the semiconductor film is formed using an atomic force microscope (AFM) or a stylus type profilometer. The level difference with the region can be measured and calculated. As described above, according to the semiconductor device in which the height of the surface protrusion at the end of the laterally grown crystal of the semiconductor film 3 is smaller than the film thickness of the semiconductor film, the TFT characteristics are improved compared to the prior art. is there. More specifically, it is effective to reduce the threshold voltage, to reduce the variation of the threshold voltage, and to reduce the subthreshold coefficient. Also, from the process point of view, the absence of protrusions at the end of the crystallization makes it possible to thin the film thickness of the gate oxide film, thereby improving throughput and TFT characteristics. Further improvement is possible.
[0034] 図 2Aは本発明の半導体デバイスにおける半導体膜結晶の平面図であり、図 2Bは 本発明の半導体デバイスにおける半導体膜の断面図である。また図 10は従来の半 導体デバイスにおける半導体膜の断面図である。本発明の半導体デバイスは、たと えば半導体膜厚を 50nmとした場合には、横方向成長結晶 11, 12の端部における 表面突起高さ Hは 30nmである（図 2B)。これに対し、従来の半導体デバイスの横方 向成長結晶 91, 92の端部における表面突起高さ Hは 50nmである（図 10)。したが つて、かかる例の場合は、本発明の半導体デバイスにおいては、表面突起高さ Hは 従来の 50nmから 30nmに低減され、半導体膜の膜厚よりも低くなつている。この表 面突起高さは、マスクパターンによってエネルギ量をコントロールし、さらに低減する ことも可能であり、リッジ以外のエリアは極めて平坦で凹凸のほとんどない、具体的に は lOnm以上の突起がほとんどない、結晶を得ることもできる。 FIG. 2A is a plan view of a semiconductor film crystal in the semiconductor device of the present invention, and FIG. 2B is a cross-sectional view of the semiconductor film in the semiconductor device of the present invention. FIG. 10 is a cross-sectional view of the semiconductor film in the conventional semiconductor device. In the semiconductor device of the present invention, for example, when the semiconductor film thickness is 50 nm, the surface protrusion height H at the end of the laterally grown crystals 11 and 12 is 30 nm (FIG. 2B). On the other hand, the surface protrusion height H at the end of the laterally grown crystal 91, 92 of the conventional semiconductor device is 50 nm (FIG. 10). Therefore, in the case of this example, in the semiconductor device of the present invention, the surface protrusion height H is reduced from the conventional 50 nm to 30 nm, which is lower than the thickness of the semiconductor film. The height of the surface protrusions can be controlled by the mask pattern and the amount of energy can be further reduced, and the area other than the ridges is extremely flat and has few irregularities, specifically, few protrusions of 10 nm or more. And crystals can also be obtained.
[0035] 本発明の半導体デバイスは、表面突起高さが半導体膜の膜厚よりも低いものであ れば、特に制限されるものではないが、半導体膜の上に形成されるゲート酸化膜の 膜厚が約 lOOnmであり、ゲート酸ィ匕膜を突き破ると電流がリークし TFTとして動作し なくなる虞があることから、表面突起高さと半導体膜の膜厚との差は 150nm以下であ るのが好ましい。また、ゲート酸ィ匕膜の膜厚が一定でなければ閾値電圧がばらつくこ とから、ゲート酸ィ匕膜の膜厚を変動させないような表面突起高さが必要となる観点か らは、表面突起高さと半導体膜の膜厚との差は lOOnm以下であるのがより好ましい。 さらに、閾値電圧はゲート酸ィ匕膜の膜厚に反比例するため、ゲート酸ィ匕膜が薄膜ィ匕 される方向にあり、このためにはできるだけ表面突起高さを低くする必要があると 、う 観点からは、表面突起高さと半導体膜の膜厚との差は 50nm以下であるのが特に好 ましい。 The semiconductor device of the present invention is not particularly limited as long as the surface protrusion height is smaller than the film thickness of the semiconductor film, but the gate oxide film formed on the semiconductor film is not limited. Since the film thickness is about 100 nm and there is a possibility that current will leak and it will not operate as a TFT if the gate oxide film is pierced, the difference between the surface protrusion height and the film thickness of the semiconductor film is 150 nm or less. Is preferred. Moreover, if the film thickness of the gate oxide film is not constant, the threshold voltage may vary, and the surface protrusion height is required so as not to change the film thickness of the gate oxide film. The difference between the height of the protrusions and the thickness of the semiconductor film is more preferably 100 nm or less. Furthermore, since the threshold voltage is in inverse proportion to the thickness of the gate oxide film, the gate oxide film is in the direction in which the thin film is deposited, and for this purpose, the height of the surface protrusion needs to be as low as possible. From the viewpoint of this, it is particularly preferable that the difference between the height of the surface protrusions and the film thickness of the semiconductor film is 50 nm or less.
[0036] 以下、上記特徴を有する本発明の半導体デバイスを製造する好適な方法 (本発明 の半導体デバイスの製造方法）について説明する。なお、本発明の半導体デバイス は、上記特徴を備えるものであればよぐ本発明の半導体デバイスの製造方法によつ て製造されたものに限定されるものではない。  Hereinafter, a preferred method for producing the semiconductor device of the present invention having the above-mentioned characteristics (a method for producing a semiconductor device of the present invention) will be described. The semiconductor device of the present invention is not limited to one manufactured by the method of manufacturing a semiconductor device of the present invention as long as it has the above-mentioned features.
[0037] 本発明の半導体デバイスの製造方法は、基板上に形成された半導体膜にレーザを 照射して該半導体膜において横方向に結晶成長させるステップと、前記横方向に結 晶成長させたレーザより低いエネルギのレーザを照射して前記横方向の成長結晶の 端部における表面突起高さを前記半導体膜の膜厚よりも低くするステップとを含む。  According to the method of manufacturing a semiconductor device of the present invention, a step of irradiating a semiconductor film formed on a substrate with a laser to grow crystals laterally in the semiconductor film, and performing the crystal growth in the lateral direction are performed. Irradiating a laser of lower energy to make the surface protrusion height at the end of the laterally grown crystal lower than the film thickness of the semiconductor film.
[0038] 本発明の半導体デバイスの製造方法における最初のステップでは、まず、従来公 知の方法である SLS法を用いて、半導体膜にレーザを照射することにより、基板上に 形成された半導体膜に横方向成長結晶を形成する。半導体膜において、結晶成長 する方向としては、主として、半導体膜の面方向と、半導体膜の厚さ方向とが挙げら れるが、「横方向」とは、上述した通り、このうち面方向のことを意味する。  In the first step of the method of manufacturing a semiconductor device of the present invention, first, a semiconductor film formed on a substrate by irradiating a semiconductor film with a laser using the SLS method which is a conventionally known method. Form laterally grown crystals. In the semiconductor film, the crystal growth direction mainly includes the plane direction of the semiconductor film and the thickness direction of the semiconductor film, and the “lateral direction” refers to the plane direction among them as described above. Means
[0039] 力かる横方向成長結晶を形成するステップにおいては、横方向に結晶成長させる レーザ照射を、結晶成長した半導体膜の部分を引き継ぐように段階的に移動させて 行うことが好ましい。ここで、「段階的にレーザ照射を行う」とは、 1回のレーザパルス で生じた横方向の結晶成長を引き継ぐように次のレーザパルスを照射し、当該レー ザパルスで生じた結晶成長を引き継ぐように次のレーザパルスを照射することを指す 。このように、段階的にレーザ照射を行うことにより最初のレーザ照射で生じた結晶の 形態を引き継いでいくことができるので、単一の結晶、すなわち単結晶を形成するこ とができる。また、直前のレーザパルス照射により生じたリッジも次のレーザパルス照 射により除去することができる。このことにより、リッジ以外のエリアは極めて平坦で凹 凸のほとんどない、具体的には lOnm以上の突起がほとんどない、結晶を得ることが できる。 [0040] 続くステップでは、前記横方向に結晶成長させたレーザより低いエネルギのレーザ を照射して前記横方向の成長結晶の端部における表面突起高さを前記半導体膜の 膜厚よりも低くする。結晶成長が横方向に進行していく場合、結晶成長の終焉におけ る端部において、表面突起高さが生じてしまうことは上述した通りであるが、本発明の 半導体デバイスの製造方法は、このような表面突起高さを半導体膜厚よりも低くする ことができることに特徴を有している。すなわち、本発明の半導体デバイスの製造方 法においては、低いエネルギのレーザ照射により、半導体膜は膜厚方向全体を完全 に溶融することができず、膜上部のみが部分的に溶融する。すると結晶核は固液界 面に多く発生し、膜中で下力 表面方向への微結晶成長が起こる。このように横方向 とは異なるメカニズムで再結晶化させることにより、表面突起高さを十分低くすること ができる。またこれは後で述べるように、半導体膜での吸収係数が大きいレーザを用 いることの利点をさらに活かしたことに特徴をもつ。 [0039] In the step of forming a laterally grown crystal, it is preferable that the laser irradiation for crystal growth in the lateral direction be performed stepwise so as to take over the portion of the semiconductor film on which the crystal is grown. Here, “perform laser irradiation in a stepwise manner” means that the next laser pulse is irradiated so as to inherit the lateral crystal growth generated by one laser pulse, and the crystal growth generated by the laser pulse is inherited. It refers to irradiating the next laser pulse. As described above, by performing laser irradiation stepwise, it is possible to take over the form of the crystal generated by the first laser irradiation, so that a single crystal, that is, a single crystal can be formed. Also, the ridge formed by the previous laser pulse irradiation can be removed by the next laser pulse irradiation. As a result, it is possible to obtain a crystal in which the area other than the ridge is extremely flat and has few concave and convex portions, specifically, few protrusions of 10 nm or more. In the subsequent step, a laser having a lower energy than that of the laterally grown crystal is irradiated to make the surface protrusion height at the end of the laterally grown crystal lower than the film thickness of the semiconductor film. . As described above, when the crystal growth proceeds in the lateral direction, the height of the surface protrusions is generated at the end of the crystal growth, as described above. It is characterized in that the height of such surface protrusions can be made lower than the semiconductor film thickness. That is, in the method of manufacturing a semiconductor device of the present invention, the semiconductor film can not be completely melted in the entire film thickness direction by laser irradiation with low energy, and only the upper portion of the film is partially melted. As a result, many crystal nuclei are generated at the solid-liquid interface, and microcrystalline growth occurs in the film toward the lower surface. By thus recrystallizing by a mechanism different from that in the lateral direction, the height of surface protrusions can be made sufficiently low. Also, as described later, this is characterized in that the advantage of using a laser having a large absorption coefficient in a semiconductor film is further utilized.
[0041] 当該ステップにお 、て、前記横方向に結晶成長させたレーザより低 、エネルギのレ 一ザの照射は、以下の（1)〜（3)のいずれかのように用いられることが、より好ましい 。（1)半導体デバイスに段階的にレーザ照射する際の最終照射において用いる、 In the step, irradiation of the laser with energy lower than that of the laterally crystal-grown laser is used as in any one of the following (1) to (3): And more preferred. (1) Used in final irradiation when laser irradiation is performed stepwise on a semiconductor device
(2)半導体デバイスに段階的にレーザ照射する際の最終照射から数段階前の照射 より用いる、 (2) A few steps prior to the final irradiation when laser irradiation is performed stepwise on a semiconductor device
(3)半導体デバイスに段階的にレーザ照射する際の最終照射の位置において用い る。  (3) The semiconductor device is used at the position of final irradiation when laser irradiation is performed stepwise.
[0042] 前記横方向に結晶成長させたレーザより低いエネルギのレーザの照射を、（1)半 導体デバイスに段階的にレーザ照射する際の最終照射において用いることで、横方 向結晶成長の最終照射の際において膜上部のみを部分的に溶融させ、結晶核を固 液界面に多く発生させ、膜中で横方向とは異なるメカニズムで再結晶化させることに より、表面突起高さを十分低くすることができる。  The laser irradiation of a lower energy than that of the laterally crystal-grown laser is used in (1) final irradiation in stepwise laser irradiation of a semiconductor device, thereby achieving the final crystal growth in the lateral direction. At the time of irradiation, only the upper part of the film is partially melted, many crystal nuclei are generated at the solid-liquid interface, and recrystallization is performed by a mechanism different from the lateral direction in the film, so that the surface protrusion height is sufficiently low. can do.
[0043] 前記横方向に結晶成長させたレーザより低!ヽェネルギのレーザの照射を、 (2)半 導体デバイスに段階的にレーザ照射する際の最終照射力 数段階前の照射より用The laser irradiation with energy lower than that of the laterally crystal-grown laser is used, and (2) the final irradiation power in the case of stepwise laser irradiation on the semiconductor device is used rather than the irradiation before the step.
V、ることで、最終照射の際のレーザエネルギが十分に低減されて 、な 、場合であつ ても、数段階前から徐々にレーザエネルギを低減させるように設計することで、横方 向成長結晶の端部における表面突起高さを半導体膜の膜厚よりも確実に低減させる ことができる。ここで、最終照射力も数段階前のレーザ照射とは、最終照射の 2〜3段 階前の段階力も照射することが好ましいが、これらに限定されるわけではなぐェネル ギの低いレーザを一緒に用いて表面突起高さを膜厚より低くするという目的を達成で きるよう〖こ、適宜設計することが好ましい。 V, by which the laser energy at the final irradiation is sufficiently reduced, even if it is designed to gradually reduce the laser energy several steps earlier, It is possible to reliably reduce the surface protrusion height at the end portion of the directionally grown crystal than the thickness of the semiconductor film. Here, it is preferable that the final irradiation power is also several stages before the laser irradiation, and it is preferable to also irradiate the stage power two to three stages before the final irradiation, but it is not limited to these. In order to achieve the purpose of making the surface projection height lower than the film thickness by using it, it is preferable to design appropriately.
[0044] また、前記横方向に結晶成長させたレーザより低いエネルギのレーザの照射を、 (3 )半導体デバイスに段階的にレーザ照射する際の最終照射の位置において用いるこ とで、他の部分には全く影響を与えることなぐリッジ部のみ突起を低減することが可 能となる。 In addition, the laser irradiation with energy lower than that of the laser crystal grown in the lateral direction is used at the position of the final irradiation when the laser irradiation is performed stepwise on the semiconductor device. It is possible to reduce the protrusion only at the ridge that has no influence on the
[0045] 図 3A〜図 3Dは、本発明の半導体デバイスの製造方法において好適に用いられる マスクを模式的に示す図である。また図 11は、従来のマスクを模式的に示す図であ る。本発明の半導体デバイスにおいては、前記横方向に結晶成長させたレーザより 低いエネルギのレーザ照射を行うために、従来のスリットパターン 101 (図 11)と比較 して細いパターン 31 (図 3A)、あるいは、回折限界以下のスリットまたはパターン 32 ( 図 3B)、 33 (図 3C)、 34 (図 3D)を有するマスクを利用して、エネルギ照射量を制御 することが好ましい。このようなマスク 31, 32, 33, 34を用いることによって、リッジを 低減できるレーザ光を作り出すことが可能となる。  FIGS. 3A to 3D are diagrams schematically showing masks preferably used in the method for manufacturing a semiconductor device of the present invention. FIG. 11 is a view schematically showing a conventional mask. In the semiconductor device according to the present invention, in order to perform laser irradiation of lower energy than the laser crystal grown in the lateral direction, a thin pattern 31 (FIG. 3A) or Preferably, the energy dose is controlled using a mask having slits or patterns 32 (FIG. 3B), 33 (FIG. 3C), 34 (FIG. 3D) below the diffraction limit. By using such masks 31, 32, 33, 34, it is possible to create laser light whose ridge can be reduced.
[0046] 従来のスリットパターン 101と比較して細いパターン 31を用いる場合には、従来と同 じょうな形状であるためマスクの設計'製作が容易であるという利点がある。また、回 折限界以下のパターン 32, 33, 34の場合は、凹凸をさらに減少させることが可能に なる。ここで、回折限界はエキシマレーザの波長と光学系によって決まり、一般には λ ΖΝΑで与えられ、約 l〜3umとなる。回折限界以下のパターンとは、たとえば、約 3umの回折限界を有するエキシマレーザと光学系とを有する装置であれば、約 2um 以下の形状となる。回折限界以下となると透過する光量が減少し、エネルギが低下 するため、小さすぎると効果がなくなる虞がある。かかる観点からは、回折限界の 1Z 4から 3Z4の大きさが好適である。  In the case where a thin pattern 31 is used as compared with the conventional slit pattern 101, there is an advantage that the mask can be easily designed and manufactured since it has the same shape as that of the conventional slit pattern. Further, in the case of the patterns 32, 33 and 34 below the limit of deformation, it is possible to further reduce the unevenness. Here, the diffraction limit is determined by the wavelength of the excimer laser and the optical system, and is generally given by λΖΝΑ, which is about 1 to 3 μm. The pattern below the diffraction limit has a shape of about 2 um or less, for example, in the case of an apparatus having an excimer laser having a diffraction limit of about 3 um and an optical system. If it becomes smaller than the diffraction limit, the amount of transmitted light decreases and the energy decreases, so if it is too small, the effect may be lost. From this point of view, the diffraction limited 1Z 4 to 3Z 4 sizes are preferable.
[0047] 本発明にお 、ては、従来のスリットパターンと比較して細 、パターンと、回折限界以 下のパターンとをうまく組み合わせることで、突起を所望の形状に変形することも勿論 可能である。 SLS法を用いて、半導体膜にレーザを照射して結晶を横方向に成長さ せる場合には、ステージの走査方向と結晶の横成長方向がほぼ垂直になるように結 晶化する。この場合、光の回折限界以下のスリットもしくはパターンを前後に有するマ スクエリアの中心線は、直前のマスクエリアの中心線と同一線上になる。 In the present invention, as a matter of course, the projection can be deformed into a desired shape by well combining the fine pattern and the pattern below the diffraction limit in comparison with the conventional slit pattern. It is possible. When a semiconductor film is irradiated with a laser to grow a crystal in the lateral direction using the SLS method, crystallization is performed so that the scanning direction of the stage and the lateral growth direction of the crystal are almost perpendicular. In this case, the center line of the mask area having slits or patterns below or equal to the diffraction limit of light is colinear with the center line of the immediately preceding mask area.
[0048] また、ステージ走査方向の往復でレーザ光を照射する場合は、光の回折限界以下 のスリットもしくはパターンを前後に有する（図 4A)力 または、最終照射の位置に従 来のスリットパターンと比較して細 、もしくは回折限界以下のパターンを有するマスク を往復で切り替えて使用する（図 4B)。図 4Aに示すようにパターンを前後に有する 場合は、横方向結晶化前に回折限界以下のマスクを通過した光が照射されるため、 凹凸をより低減できるという効果がある。なお、図 12には、比較として従来のレーザ光 の照射例を模式的に示して 、る。  In addition, in the case of irradiating the laser beam in a reciprocating manner in the stage scanning direction, a slit or pattern below the diffraction limit of the light may have back and forth (FIG. 4A) or a slit pattern according to the position of the final irradiation. In comparison, use a mask that has a fine pattern or a pattern below the diffraction limit by switching back and forth (Fig. 4B). As shown in FIG. 4A, in the case of having a pattern in front and back, since light passing through a mask below the diffraction limit is irradiated before transverse crystallization, there is an effect that unevenness can be further reduced. Note that FIG. 12 schematically shows an example of conventional laser light irradiation as a comparison.
[0049] 本発明の半導体膜の製造方法に用いるレーザ光は、基板に影響を与えないため に、半導体膜での吸収係数が大きいことが望ましい。より具体的には、紫外域の波長 を有することが好ましい。たとえば、波長 308nmのエキシマレーザパルスが挙げられ る。なお、横方向結晶成長のためのレーザ照射においては、たとえば膜厚約 50nm のアモルファスシリコンにレーザ照射して横方向成長結晶を有する半導体膜 3を形成 する場合には、 SLS法に必要なエキシマレーザのエネルギ量は 2〜8kj/m2である 。また、横方向結晶成長させたレーザより低いエネルギのレーザの照射の際のエキシ マレーザのエネルギ量は 0. 5〜4kjZm2である。 The laser beam used in the method for producing a semiconductor film of the present invention preferably has a large absorption coefficient in the semiconductor film so as not to affect the substrate. More specifically, it is preferable to have a wavelength in the ultraviolet range. For example, an excimer laser pulse having a wavelength of 308 nm can be mentioned. In addition, in the case of laser irradiation for lateral crystal growth, for example, when forming a semiconductor film 3 having laterally grown crystals by laser irradiation on amorphous silicon with a film thickness of about 50 nm, the excimer laser necessary for the SLS method The energy content of is 2 to 8 kj / m 2 . In addition, the energy amount of the excimer laser at the time of irradiation of a laser with a lower energy than that of the laterally crystal-grown laser is 0.5 to 4 kjZm 2 .
[0050] また、本発明の半導体薄膜の製造方法に用いるレーザ光は、 1回の照射あたり固 体状態にある半導体膜を溶融させる照射面積あたりのエネルギ量、具体的には半導 体膜を全膜厚において融点以上の温度に加熱することのできるエネルギ量を有する ことが好ましい。このエネルギ量は、半導体膜の材質の種類、半導体膜の膜厚、結晶 化領域の面積などにより変化し、一義的に定めることができないため、適宜適当なェ ネルギ量を有するレーザ光を用いることが望まし 、。  Further, the laser beam used in the method for producing a semiconductor thin film of the present invention is an amount of energy per irradiation area for melting the semiconductor film in a solid state per one irradiation, specifically a semiconductor film. It is preferable to have an amount of energy that can be heated to a temperature above the melting point in the entire film thickness. The amount of energy varies depending on the type of the material of the semiconductor film, the film thickness of the semiconductor film, the area of the crystallization region, etc. and can not be uniquely determined. Therefore, use laser light having an appropriate energy amount as appropriate. Hoped.
[0051] ここで、積層された半導体膜を結晶化するのに用いる一般的な装置について、図 5 を用いて説明する。図 5は、上述した本発明の半導体デバイスの製造方法に用いる ことができる装置の一例を概念的に示す図である。図 5に示す例の装置は、レーザ発 振器 42、可変減衰器 43、フィールドレンズ 44、マスク 45、結像レンズ 46、サンプル ステージ 47およびいくつかのミラー、さらには均一照光学系を含んでいる。これらの 部材は、コントローラ 41により制御される。このような装置を用いることにより、ステージ 47上の半導体デバイス 5に放射パルスを供給することができる。また、リッジに照射さ れるレーザ光に対し、マスク 45として光の回折限界以下のスリットもしくはパターンを 有するマスクを用いることで、レーザエネルギを減衰させることができる。このような装 置は、当業者であれば当分野における各種部品を適宜組み合わせて容易に実現す ることがでさる。 Here, a general apparatus used to crystallize the stacked semiconductor film will be described with reference to FIG. FIG. 5 is a diagram conceptually showing an example of an apparatus that can be used for the method of manufacturing a semiconductor device of the present invention described above. The example device shown in FIG. It includes an exciter 42, a variable attenuator 43, a field lens 44, a mask 45, an imaging lens 46, a sample stage 47 and several mirrors, as well as uniform illumination optics. These members are controlled by the controller 41. By using such an apparatus, a radiation pulse can be supplied to the semiconductor device 5 on the stage 47. In addition, laser energy can be attenuated by using a mask having a slit or a pattern below the diffraction limit of light as the mask 45 with respect to the laser light irradiated to the ridge. Such a device can be easily realized by those skilled in the art by appropriately combining various parts in the field.
[0052] 図 6は、本発明の半導体デバイスの製造装置を好ましい一例を概念的に示す図で ある。本発明の半導体デバイスの製造方法は、図 5に示したような一般的な装置を用 いて行うことができるが、特に、図 6に示す本発明の半導体デバイスの製造装置を好 適に用いることができる。本発明は、上述した本発明の半導体デバイスの製造方法 に好適に用いられる装置であって、第一のレーザ発振器 52と、第二のレーザ発振器 58と、これらの 2つのレーザ発振器を制御するコントローラ 51とを備えることを特徴と する、半導体デバイスの製造装置をも提供するものである。  FIG. 6 is a view conceptually showing a preferable example of the semiconductor device manufacturing apparatus of the present invention. Although the method of manufacturing a semiconductor device of the present invention can be performed using a general apparatus as shown in FIG. 5, in particular, the semiconductor device manufacturing apparatus of the present invention shown in FIG. Can. The present invention is an apparatus suitably used for the method of manufacturing a semiconductor device of the present invention described above, which is a controller for controlling a first laser oscillator 52, a second laser oscillator 58, and these two laser oscillators. And an apparatus for producing a semiconductor device.
[0053] 図 6に示す本発明の半導体デバイスの製造装置においては、第一のレーザ発振器 52によるレーザを、半導体膜の横方向の結晶成長のための照射に用い、第二のレ 一ザ発振器 58によるレーザを、溶融した半導体膜の温度低下を抑制するためのァシ ストレーザとして用いる。このような構成を採ることにより、溶融した半導体膜が再凝固 するまでの時間を延長することができ、生成される横方向結晶の粒径を大幅に伸ば すことができる。  In the apparatus for manufacturing a semiconductor device according to the present invention shown in FIG. 6, the laser by the first laser oscillator 52 is used for irradiation for lateral crystal growth of the semiconductor film, and the second laser oscillator is used. The laser according to 58 is used as an assist laser for suppressing the temperature drop of the melted semiconductor film. By adopting such a configuration, it is possible to extend the time until the molten semiconductor film re-solidifies, and it is possible to significantly increase the grain size of the transverse crystal to be generated.
[0054] 本発明の半導体デバイスの製造装置においては、第一のレーザ発振器から発生 するレーザ (第一のレーザ光)の波長が、半導体膜 (固体状態の半導体膜)に吸収さ れやすい波長であり、第二のレーザ発振器力 発生するレーザ (第二のレーザ光)の 波長が、基板または溶融状態の半導体膜に吸収されやすい波長であることが好まし い。かかる第一のレーザ光としては、たとえば、波長 308nmのエキシマレーザパルス が挙げられる。また、第二のレーザ光としては、波長 532nmの YAGレーザ、波長 10 64nmの YAGレーザ、波長 10. 6 mの炭酸ガスレーザなどが挙げられる。 [0055] 本発明の半導体膜の製造装置に用いる第一および第二のレーザ光エネルギの合 計は、照射面積あたりの、 1回の照射あたり固体状態にある半導体膜を溶融させうる エネルギ量を有することが好ましい。あるいは、第一のレーザ光が照射面積あたりのIn the semiconductor device manufacturing apparatus of the present invention, the wavelength of the laser (first laser beam) generated from the first laser oscillator is a wavelength at which the semiconductor film (semiconductor film in the solid state) is easily absorbed. It is preferable that the wavelength of the laser (second laser beam) generated by the second laser oscillator is a wavelength that is easily absorbed by the substrate or the semiconductor film in a molten state. As such a first laser beam, for example, an excimer laser pulse having a wavelength of 308 nm can be mentioned. Further, as the second laser light, a YAG laser with a wavelength of 532 nm, a YAG laser with a wavelength of 10 64 nm, a carbon dioxide gas laser with a wavelength of 10.6 m, etc. may be mentioned. The total of the first and second laser light energy used in the apparatus for manufacturing a semiconductor film of the present invention is the amount of energy capable of melting the semiconductor film in a solid state per one irradiation, per irradiation area. It is preferable to have. Alternatively, the first laser beam is per irradiated area
、 1回の照射あたり固体状態にある半導体膜を溶融させうるエネルギ量を有し、第二 のレーザ光が照射面積あたりの、 1回の照射あたり固体状態にある半導体膜を溶融さ せうるエネルギ量未満である、照射面積あたりのエネルギ量を有するように設定する ことも可能である。これらのエネルギ量は、半導体膜の材質の種類、半導体膜の膜厚 、結晶化領域の面積などにより変化し、一義的に定めることはできないため、上述し た本発明の半導体デバイスの製造方法における適用すべき態様に併せて、適宜適 当なエネルギ量を有するレーザ光を採用することが望ましい。たとえば、半導体膜と してアモルファスシリコン 50nmを用いる場合には、 SLS法に必要な第一のレーザの エネルギ量は l〜5kjZm2であり、第二のレーザのエネルギ量は 0. 5〜4kjZm2で ある。 An energy amount capable of melting the semiconductor film in a solid state per one irradiation, and an energy capable of melting the semiconductor film in a solid state per one irradiation per second irradiation light area; It is also possible to set the amount of energy per illuminated area to be less than the amount. The amount of energy varies depending on the type of the material of the semiconductor film, the film thickness of the semiconductor film, the area of the crystallization region, and the like, and can not be uniquely determined. Therefore, in the above-described method of manufacturing a semiconductor device of the present invention It is desirable to adopt a laser beam having an appropriate amount of energy as appropriate in accordance with the mode to be applied. For example, when 50 nm of amorphous silicon is used as a semiconductor film, the amount of energy of the first laser required for the SLS method is 1 to 5 kjZm 2 and the amount of energy of the second laser is 0.5 to 4 kj Zm 2 It is.
[0056] 図 7は、本発明の半導体デバイスの製造装置における、第一のレーザ光および第 二のレーザ光の照射時刻と出力 (放射照度)との関係の概要を説明するグラフである 。図 7のグラフにおいて、横軸は時間（時)を表し、縦軸は、出力（単位: WZm2)を表 す。また図 7のグラフにおいて、第一のレーザ光のグラフは参照符 61で示され、第二 のレーザ光のグラフは参照符 62で示される。本発明の半導体デバイスの製造装置 は、たとえば、第一のレーザが、時刻 t = 0に照射を開始し、 t=t'に出力が 0となるよ うに照射するよう実現される。また、本発明の半導体デバイスの製造装置では、たとえ ば、第二のレーザが時刻 tlと t2の間において高出力で放射し、他は低出力で放射 するように実現される。なお、 tl < t2である。第一のレーザ光および第二のレーザ光 の照射時刻と出力との関係は、特にこの関係にあることを限定するものではなぐ時 刻 tlは正の値でも負の値でも構わない。すなわち、第二のレーザ光の照射開始時刻 は、第一のレーザ光の照射開始時刻の前であっても後であっても構わない。時刻 t2 を適当に設定することにより、溶融した半導体膜が再凝固するまでの時間を延長する ことができ、生成される横方向結晶の粒径を大幅に伸ばすことができる。好ましくは、 t' < t2である。また、 tl < t'であることが好ましい。このような第一のレーザ光および 第二のレーザ光の照射は、コントローラ 51により適宜制御されるようにして実現される 。コントローラ 51としては、従来公知の適宜の制御手段を特に制限なく用いることが できる。 FIG. 7 is a graph showing an outline of the relationship between the irradiation time of the first laser beam and the second laser beam and the output (irradiance) in the semiconductor device manufacturing apparatus of the present invention. In the graph of FIG. 7, the horizontal axis represents time (hour), and the vertical axis represents output (unit: WZm 2 ). Further, in the graph of FIG. 7, the graph of the first laser beam is indicated by reference numeral 61, and the graph of the second laser beam is indicated by reference numeral 62. The apparatus for manufacturing a semiconductor device according to the present invention is realized, for example, such that the first laser starts irradiation at time t = 0 and outputs so that t = t ′ becomes zero. Also, in the semiconductor device manufacturing apparatus of the present invention, for example, the second laser is realized to emit at high power between the times tl and t2, and to emit the other at low power. Note that tl <t2. The relationship between the irradiation time of the first laser beam and the second laser beam and the output is not particularly limited to this relationship. The time tl may be a positive value or a negative value. That is, the irradiation start time of the second laser beam may be before or after the irradiation start time of the first laser beam. By setting the time t2 appropriately, it is possible to extend the time until the molten semiconductor film re-solidifies, and it is possible to significantly extend the grain size of the transverse crystal to be generated. Preferably, t '<t2. Moreover, it is preferable that tl <t '. Such first laser light and The irradiation of the second laser beam is realized by being appropriately controlled by the controller 51. As the controller 51, conventionally known appropriate control means can be used without particular limitation.
[0057] なお、図 3A〜図 3Dには、本発明の半導体デバイスの製造方法において好適に用 いられるマスクを示した力 このようなマスクも新規なものであって、本発明に包含され る。すなわち、本発明は、基板上に形成された半導体膜にレーザを照射して該半導 体膜にお 1、て横方向に結晶成長させ、前記横方向に結晶成長させたレーザより低！、 エネルギのレーザを照射して前記横方向の成長結晶の端部における表面突起高さ を前記半導体膜の膜厚よりも低くする半導体デバイスの製造方法において、横方向 に結晶成長させたレーザより低いエネルギのレーザ照射を行うために用いられる、回 折限界以下のスリットもしくはパターンを有することを特徴とするマスクも提供する。  FIGS. 3A to 3D show the force of a mask suitably used in the method of manufacturing a semiconductor device of the present invention. Such a mask is also novel and is included in the present invention. . That is, according to the present invention, the semiconductor film formed on the substrate is irradiated with a laser so that the semiconductor film is laterally grown and the crystal is laterally grown, and the crystal is laterally grown lower than the laser! A method of manufacturing a semiconductor device in which the height of surface protrusions at the end of the laterally grown crystal is made lower than the film thickness of the semiconductor film by irradiating an energy laser, which is lower than the laterally grown crystal laser There is also provided a mask characterized by having a slit or pattern below the diffraction limit, which is used to perform laser irradiation of energy.
[0058] 本発明はさらに、上記マスクを備える製造装置も提供するものである。すなわち、本 発明は、基板上に形成された半導体膜にレーザを照射して該半導体膜において横 方向に結晶成長させ、前記横方向に結晶成長させたレーザより低 、エネルギのレー ザを照射して前記横方向の成長結晶の端部における表面突起高さを前記半導体膜 の膜厚よりも低くする半導体デバイスの製造方法において、横方向に結晶成長させ たレーザより低いエネルギのレーザ照射を行うために用いられる、回折限界以下のス リットもしくはパターンを有するマスクを備える製造装置も提供する。  The present invention further provides a manufacturing apparatus provided with the above mask. That is, according to the present invention, a semiconductor film formed on a substrate is irradiated with a laser to grow crystals in the lateral direction in the semiconductor film, and a laser having energy lower than that of the laser grown in the lateral direction is irradiated. In the method of manufacturing a semiconductor device, in which the height of the surface protrusion at the end of the laterally grown crystal is made smaller than the film thickness of the semiconductor film, laser irradiation with energy lower than that of the laterally grown crystal is performed. Also provided is a manufacturing apparatus comprising a mask having a slit or pattern below the diffraction limit, which is used for
[0059] 今回開示された実施の形態はすべての点で例示であって制限的なものではないと 考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって 示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが 意図される。  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the scope of claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims.

Claims

請求の範囲 The scope of the claims
[1] 基板 (1)上に半導体膜 (3)が形成された半導体デバイス (5)であって、該半導体膜  [1] A semiconductor device (5) in which a semiconductor film (3) is formed on a substrate (1), which is a semiconductor film
(3)は横方向成長結晶を有し、かつ、該横方向成長結晶の端部において表面突起 高さが前記半導体膜 (3)の膜厚より低 ヽことを特徴とする半導体デバイス (5)。  (3) A semiconductor device characterized in that it has a laterally grown crystal, and the height of the surface protrusion is lower than the film thickness of the semiconductor film (3) at the end of the laterally grown crystal. .
[2] 前記横方向成長結晶は、前記半導体膜 (3)にレーザ照射することにより結晶成長 された結晶であることを特徴とする、請求の範囲第 1項に記載の半導体デバイス (5)  [2] The semiconductor device according to claim 1, wherein the laterally grown crystal is a crystal grown by laser irradiation to the semiconductor film (3).
[3] 前記横方向成長結晶は、前記レーザ照射を、レーザ照射により横方向に結晶成長 した部分を引き継ぐように半導体膜の面方向に段階的に移動して、前記部分の結晶 を引き継ぐことにより、結晶成長が拡大された領域であることを特徴とする、請求の範 囲第 2項に記載の半導体デバイス (5)。 [3] The laterally grown crystal is moved stepwise in the plane direction of the semiconductor film so as to inherit the portion of the crystal grown in the lateral direction by the laser irradiation, so that the crystal of the portion is taken over. The semiconductor device (5) according to claim 2, characterized in that it is a region in which crystal growth is expanded.
[4] 横方向結晶成長の端部における表面突起高さは、回折限界以下のスリットもしくは パターンを通過した光を利用し、前記横方向成長結晶を形成するための前記レーザ のエネルギよりも低いエネルギを有するレーザを照射することにより、半導体膜 (3)の 膜厚よりも低くされたことを特徴とする、請求の範囲第 2項に記載の半導体デバイス ( 5)。 [4] The height of surface projections at the end of lateral crystal growth is lower than the energy of the laser for forming the laterally grown crystal by using light passing through a slit or pattern below the diffraction limit. The semiconductor device (5) according to claim 2, characterized in that the film thickness of the semiconductor film ( 3 ) is made lower by irradiating a laser having the above.
[5] 前記横方向成長結晶を形成するための前記レーザのエネルギよりも低!、エネルギ を有するレーザを、前記半導体デバイスに段階的にレーザ照射する際の最終照射に おいて用いることを特徴とする、請求の範囲第 4項に記載の半導体デバイス（5)。  [5] A laser having energy lower than the energy of the laser for forming the laterally grown crystal is used in final irradiation when the semiconductor device is stepwise irradiated with the laser. The semiconductor device (5) according to claim 4, wherein
[6] 前記横方向成長結晶を形成するための前記レーザのエネルギよりも低!、エネルギ を有するレーザを、前記半導体デバイスに段階的にレーザ照射する際の最終照射か ら数段階前の照射より用いることを特徴とする、請求の範囲第 4項に記載の半導体デ バイス（5)。  [6] A laser having energy lower than the energy of the laser for forming the laterally grown crystal, and a laser having energy, which is more than the irradiation several steps after the final irradiation when the semiconductor device is stepwise irradiated with the laser The semiconductor device (5) according to claim 4, characterized in that it is used.
[7] 前記横方向成長結晶を形成するための前記レーザのエネルギよりも低!、エネルギ を有するレーザを、前記半導体デバイスに段階的にレーザ照射する際の最終照射の 位置において用いることを特徴とする、請求の範囲第 4項に記載の半導体デバイス（ 5)。  [7] A laser having energy lower than the energy of the laser for forming the laterally grown crystal is used at the position of final irradiation when the semiconductor device is stepwise irradiated with the laser. The semiconductor device (5) according to claim 4, wherein
[8] 請求の範囲第 1項に記載された半導体デバイスを製造するための方法であって、 基板上に形成された半導体膜にレーザを照射して該半導体膜において横方向に 結晶成長させるステップと、前記横方向に結晶成長させたレーザより低 、エネルギの レーザを照射して前記横方向の成長結晶の端部における表面突起高さを前記半導 体膜の膜厚よりも低くするステップとを含む、半導体デバイスの製造方法。 [8] A method for manufacturing a semiconductor device according to claim 1, A step of irradiating a semiconductor film formed on the substrate with a laser to grow crystals laterally in the semiconductor film, and irradiating a laser of energy lower than that of the crystal grown in the horizontal direction so as to form the lateral direction And making the surface protrusion height at the end of the grown crystal smaller than the film thickness of the semiconductor film.
[9] 前記半導体膜において横方向に結晶成長させるレーザ照射を、結晶成長した半導 体膜の部分を引き継ぐように段階的に移動させて行うことを特徴とする、請求の範囲 第 8項に記載の半導体デバイスの製造方法。  [9] The laser irradiation for causing crystal growth in the lateral direction in the semiconductor film is performed by stepwise moving so as to take over a portion of the crystal-grown semiconductor film. The manufacturing method of the described semiconductor device.
[10] 前記横方向に結晶成長させたレーザより低いエネルギのレーザ照射を、レーザを 段階的に移動させて照射するステップにおける最終照射に用いることを特徴とする、 請求の範囲第 9項に記載の半導体デバイスの製造方法。  [10] The laser irradiation with energy lower than that of the laterally crystal-grown laser is used for final irradiation in the step of moving the laser stepwise and irradiating, as described in claim 9. Semiconductor device manufacturing method.
[11] 前記横方向に結晶成長させたレーザより低いエネルギのレーザ照射を、レーザを 段階的に移動させて照射するステップにおける最終照射力 数段階前の照射より用 いることを特徴とする、請求の範囲第 9項に記載の半導体デバイスの製造方法。  [11] The laser irradiation of lower energy than the laterally crystal-grown laser is used from the irradiation before the final irradiation power step in the step of moving the laser stepwise and irradiating the laser. 10. A method of manufacturing a semiconductor device according to claim 9.
[12] 前記横方向に結晶成長させたレーザより低いエネルギのレーザ照射を、レーザを 段階的に移動させて照射するステップにおける最終照射の位置において用いること を特徴とする、請求の範囲第 9項に記載の半導体デバイスの製造方法。  [12] The laser irradiation with energy lower than that of the laterally crystal-grown laser is used at the position of final irradiation in the step of moving the laser stepwise and irradiating the laser. The manufacturing method of the semiconductor device as described in-.
[13] 前記横方向に結晶成長させたレーザより低!ヽェネルギのレーザ照射を行うために、 回折限界以下のスリットもしくはパターンを有するマスクを利用してエネルギ照射量を 制御することを特徴とする、請求の範囲第 8項に記載の半導体デバイスの製造方法。  [13] In order to perform laser irradiation with energy lower than that of the laser crystal grown in the lateral direction, it is characterized in that the energy irradiation amount is controlled using a mask having a slit or pattern below the diffraction limit. A method of manufacturing a semiconductor device according to claim 8.
[14] 請求の範囲第 8項に記載の半導体デバイスの製造方法に用いる半導体デバイスの 製造装置であって、  [14] A manufacturing apparatus of a semiconductor device used in the method of manufacturing a semiconductor device according to claim 8;
第一のレーザ発振器 (42)と、第二のレーザ発振器 (58)と、これら 2つのレーザ発 振器を制御するコントローラ（51)とを備える、半導体デバイスの製造装置。  An apparatus for manufacturing a semiconductor device, comprising: a first laser oscillator (42), a second laser oscillator (58), and a controller (51) for controlling these two laser oscillators.
[15] 第二のレーザ発振器（58)力 発生するレーザのェネルギカ 第一のレーザ発振 器 (42)力も発生するレーザのエネルギよりも低 、ことを特徴とする、請求の範囲第 1[15] A second laser oscillator (58) power generation energy of the laser generated by the first laser oscillator (42) power is also lower than the energy of the laser generated.
4項に記載の半導体デバイスの製造装置。 The manufacturing apparatus of the semiconductor device of 4 items.
[16] 第一のレーザ発振器 (42)力 発生するレーザの波長が、半導体膜に吸収されや すい波長であり、第二のレーザ発振器 (58)力 発生するレーザの波長が、基板また は溶融状態の半導体膜に吸収されやすい波長であることを特徴とする、請求の範囲 第 14項に記載の半導体デバイスの製造装置。 [16] The first laser oscillator (42) The wavelength of the generated laser is a wavelength which is easily absorbed by the semiconductor film, and the second laser oscillator (58) the force of the generated laser is the substrate or The semiconductor device manufacturing apparatus according to claim 14, wherein is a wavelength which is easily absorbed by the molten semiconductor film.
[17] 請求の範囲第 8項に記載の半導体デバイスの製造方法において、横方向に結晶 成長させたレーザより低 、エネルギのレーザ照射を行うために用いられるマスクであ つて、 [17] A method of manufacturing a semiconductor device according to claim 8, which is a mask used to perform laser irradiation with energy lower than that of a laterally crystal-grown laser.
回折限界以下のスリットもしくはパターンを有することを特徴とするマスク。  A mask having a slit or pattern below the diffraction limit.
[18] 請求の範囲第 8項に記載の半導体デバイスの製造方法において、横方向に結晶 成長させたレーザより低 、エネルギのレーザ照射を行うために用いられる製造装置 であって、 [18] A method of manufacturing a semiconductor device according to claim 8, which is a manufacturing apparatus used to perform laser irradiation with energy lower than that of a crystal grown in the lateral direction,
回折限界以下のスリットもしくはパターンを有するマスクを備えることを特徴とする製 造装置。  A manufacturing apparatus comprising a mask having a slit or a pattern below the diffraction limit.
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