CN100514561C - Crystalline film and its manufacture method using laser - Google Patents
Crystalline film and its manufacture method using laser Download PDFInfo
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- CN100514561C CN100514561C CNB2007101423450A CN200710142345A CN100514561C CN 100514561 C CN100514561 C CN 100514561C CN B2007101423450 A CNB2007101423450 A CN B2007101423450A CN 200710142345 A CN200710142345 A CN 200710142345A CN 100514561 C CN100514561 C CN 100514561C
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- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
Abstract
An object to be processed having a thin film of an amorphous material formed on the surface thereof is provided. The thin film is fused by projecting a pulse laser beam having cross-section elongated in one direction to the surface thereof and then the thin film is solidified. Crystal grains are generated continuously in the direction of the long axis within a first stripe region extending in the direction of the long axis and spaced apart by some distance from the edge and the central axis out of regions between an edge extending in the direction of the long axis and the center line of the beam incident region.
Description
The application is that application number is 200380102421.5, the applying date is on October 14th, 2003, denomination of invention is divided an application for the patent application of " crystalline film and utilize laser to make the method for crystalline film ".
Technical field
The present invention relates to polycrystalline film manufacture method and crystalline film, particularly relate to by make the crystalline film manufacture method of its crystallization and the crystalline film made of method thus to the amorphous film illuminating laser beam.
Crystalline film can be used to low temperature polycrystalline TFT LCD, solar panel, paper mold LCD and OLED display etc.
Background technology
Continuously transverse solidifying (SLS) technology is known, and it comprises to amorphous silicon membrane and applies excimer laser so that its fusion and solidify and at horizontal (direction in the face of film) grown crystal repeatedly.Below traditional SLS technology is described in detail.
Pulse laser beam passes the slit that for example about 3-30 μ m is wide, 100 μ m are long after its cross section is made into elongated shape.The pulse laser beam that passes the slit is imported into optical focusing system, and optical focusing system focuses on the slit on the surface of amorphous silicon membrane.Pulse laser beam becomes and incides on the amorphous silicon film.The multiplication factor of this optical focusing system is for example 1/3.Laser beam is about 33 μ m at the about 1-10 μ of the lip-deep irradiated region field width of amorphous silicon film m.The beam intensity broad ways of irradiation area is approximately rectangular.
When laser beam becomes when inciding on the amorphous silicon film amorphous silicon fusion.Because the cooling rate near the melting zone boundary is inner faster than melting zone, solidifies from boundary vicinity.Solidify the zone and become a nucleus, thus crystal thus nucleus to the melting zone growth inside.Because crystal growth starts from the border of two longer sides of irradiation area, near the center of irradiation area, form a grain boundary that is positioned at the intergranule of growing along its Width since two borders.
By broad ways the pulse laser beam incident area is moved 50% of about this width and apply second pulse laser beam.A near zone of one side of the grain boundary that forms by the center of first pulse laser beam at irradiation area is by fusion once more.In this zone not once more the crystal grain of fusion become seed crystal, crystal is in the growth of melt region more thus.
By in the incident area of mobile pulse laser beam, carrying out laser radiation repeatedly, can be along the moving direction grown crystal of direction of illumination.
Following document 1-3 discloses use Nd:YAG second harmonic laser, beam cross section, and linearly type and laser beam are applied on the amorphous silicon layer with along technology such as cross growth crystal.Following document 4 and 5 discloses the use excimer laser and by patterned mask laser beam has been put on the amorphous silicon layer with along technology such as cross growth crystal.
(document 1) JPA-2000-260731
(document 2) JPA-2000-286195
(document 3) JPA-2000-286211
(document 4) JPA-2000-505241
(document 5) JPA-2001-274088
Up to now, people expect to grasp the technology that forms big crystal grain always.The new technology that the purpose of this invention is to provide a kind of cross growth crystal.
Summary of the invention
According to an aspect of the present invention, provide a kind of polycrystalline film manufacture method, it may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface;
(b) apply at least one pulse laser beam to this film, this pulse laser beam has the elongated shape beam cross section in the direction in this film surface upper edge, and the light distribution along the short-axis direction of beam cross section has in the central area strong, asymmetric first shape that weakens to the border, described pulse laser beam by fall with a mask light shield along equal during the minor axis of beam cross section has the light distribution of central area shape strong and that weaken towards the border or be weaker than first light intensity one first skirt section a part not light shield fall that the part in one second skirt section or light shield fall to equal or the mode of a part that is weaker than second skirt section of one second light intensity obtains, a little less than described first light intensity of wherein said second beam intensity ratio;
(c) incoming position of mobile pulse laser beam and at least one in the workpiece, so that the incoming position of the pulse laser beam direction that long axis direction with the beam cross section of pulse laser beam intersects in the surperficial upper edge of film moves, and make the zone that has applied one pulse laser beam overlapping with the area part that applies last autolyte impulse light beam;
(d) apply at least one pulse laser beam to this film, this pulse laser beam has the light distribution of this first shape; And
(e) replace repeating step (c) and step (d).
According to a further aspect in the invention, provide a kind of polycrystalline film manufacture method, it may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface;
(b) apply at least one pulse laser beam to this film, this pulse laser beam has the elongated shape beam cross section in the direction in this film surface upper edge, and the light distribution along the short-axis direction of beam cross section has first shape that obtains by at least the first skirt portion of falling light distribution with a mask light shield, and this light distribution is strong and weaken towards the border in the central area;
(c) incoming position of mobile pulse laser beam and at least one in the workpiece, so that the incoming position of the pulse laser beam direction that long axis direction with the beam cross section of pulse laser beam intersects in the surperficial upper edge of film moves, and make the zone that has applied one pulse laser beam overlapping with the area part that applies last autolyte impulse light beam;
(d) apply at least one pulse laser beam to this film, this pulse laser beam has the light distribution of this first shape; And
(e) replace repeating step (c) and step (d).
In accordance with a further aspect of the present invention, provide a kind of polycrystalline film manufacture method, it may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface; And
(b) apply pulse laser beam to this film, with with this film fusion, this pulse laser beam has the elongated shape beam cross section in the direction in the surperficial upper edge of this film, this film is solidified, in first belt-like zone, to form crystal grain, this first belt-like zone extends along the long axis direction of beam feeding sputtering area, and be in the beam feeding sputtering area in the zone between the border of heart line wherein and the beam feeding sputtering area that extends along long axis direction, and with described border and center line from a distance, and form a random distribution zone that contacts with first belt-like zone in the portion of external zone of first belt-like zone, the crystal grain in this random distribution zone is random distribution and less than the crystal grain that forms in first belt-like zone.
By carrying out the pulse laser beam irradiation in the above described manner, can obtain big crystal grain.
Description of drawings
Fig. 1 is the schematic plan view of the employed laser annealing system of embodiments of the invention.
Fig. 2 A is the viewgraph of cross-section and the pulse energy density distribution map of the employed pulse laser of first embodiment on surface of the work of a workpiece, and Fig. 2 B is the plane schematic plan view of a polycrystallization workpiece.
Fig. 3 is the sketch according to the SEM photo of the polycrystalline film of the method manufacturing of first embodiment.
Fig. 4 A is the temperature of molten silicon and the graph of a relation of rate of crystalline growth, and Fig. 4 B is the graph of a relation of temperature and nucleus formation rate (the nucleus formation factor).
Fig. 5 A is the width of beam cross section and the graph of a relation between the crystallite dimension (particle diameter), and Fig. 5 B is the graph of a relation between pulse energy density distribution gradient and the crystallite dimension.
Fig. 6 is the graph of a relation between pulse duration and the crystallite dimension.
Fig. 7 is the view of one example of laser beam waveform when the twice pulse laser beam puts on the same area.
Fig. 8 A-8G is in the cross sectional representation according to the film in the manufacture process of the polycrystalline film manufacture method of second embodiment.
Fig. 9 is the sketch according to the SEM photo of the polycrystalline film of the method manufacturing of second embodiment.
Figure 10 is the crystal growth length of per pass irradiation and makes graph of a relation between the required Duplication of whole regional polycrystallization.
Figure 11 is the graph of a relation of the absorption coefficient of wavelength and monocrystalline silicon and amorphous silicon.
Figure 12 A be polycrystallization zone with according to the graph of a relation between the pulse energy density distribution of the employed pulse laser beam of polycrystalline film manufacture method of the 3rd embodiment, Figure 12 B is the schematic diagram of the polycrystalline film of manufacturing.
Figure 13 A be polycrystallization zone with according to the graph of a relation between the pulse energy density distribution of the employed pulse laser beam of polycrystalline film manufacture method of the 4th embodiment, Figure 13 B is the schematic diagram of the polycrystalline film of manufacturing.
Figure 14 is that a work piece substrate and is used for viewgraph of cross-section and the pulse energy density distribution map according to the employed light shielding plate of polycrystal film manufacture method of the 5th embodiment.
Figure 15 A-15C shows the schematic diagram how polycrystallization in the polycrystalline film manufacture method of the 5th embodiment carries out.
Figure 16 is that a work piece substrate and is used for viewgraph of cross-section and the pulse energy density distribution map according to the employed light shielding plate of polycrystal film manufacture method of the 6th embodiment.
Figure 17 A-17C shows the schematic diagram how polycrystallization in the polycrystalline film manufacture method of the 6th embodiment carries out.
Embodiment
Fig. 1 is the schematic diagram of the employed laser annealing system of embodiments of the invention.This laser annealing system comprises process chamber 40, transfer chamber 82, transfer chamber 83 and 84, lasing light emitter 71, homogenizer 72, ccd video camera 88 and video-frequency monitor 89.A straight-line motion mechanism 60 has been installed on process chamber 40, and it comprises bellows 67, connector 63 and 65, linear steering mechanism 64 and linear motor 66 etc.This straight-line motion mechanism 60 can make the workbench 44 that is arranged in process chamber 40 carry out translational motion.
Process chamber 40 links to each other by gate valve 85 with transfer chamber 82, and transfer chamber 82 links to each other by gate valve 86 with transfer chamber 83, and transfer chamber 82 links to each other by gate valve 87 with transfer chamber 84. Vacuum pump 91,92 and 93 is equipped with respectively in process chamber 40 and transfer chamber 83,84, so that the inside of each chamber can vacuumize.
The upper wall that passes process chamber 40 forms a laser beam transmission quartz window 38.Except that quartz, also can use optical glass such as BK7.Enter attenuator 76 from the pulse laser beam of lasing light emitter 71 outputs, be transfused to homogenizer 72 then.Homogenizer 72 cross section of laser beam is formed elongated shape and with intensity of laser beam along its longitudinal axis homogenization.The laser beam that passes homogenizer 72 sees through the elongated shape quartz window 38 have with the corresponding shape of beam cross section, and incides in the substrate on the workbench 44 that remains in the process chamber 40.Adjust the relative position of homogenizer 72 and substrate, so that substrate surface is consistent with the plane that homogenizes.
The direction of translatory motion of the workbench 44 that is driven by straight-line motion mechanism 60 is vertical vertical with quartz window 38.Therefore, wideer zone applies laser beam and makes the amorphous semiconductor film polycrystallization that is formed on the substrate surface on can basad surface.With 88 pairs of substrate surface shootings of ccd video camera, thereby can on video-frequency monitor 89, observe the substrate surface of handling.
With reference to Fig. 2 A, 2B and Fig. 3 the polycrystalline film manufacture method of first embodiment is described below.
Fig. 2 A is the viewgraph of cross-section of sample workpiece 1 and the laser beam pulse energy density distribution map at the surperficial upper edge of workpiece 1 short-axis direction.Workpiece 1 has the thick substrate of glass 2 by the three-layer structure that constitutes with the lower part: 0.7mm; The silicon dioxide film 3 that the 100nm on the surface of cover glass substrate is thick; And be formed at the thick amorphous silicon film 4 of 50nm on the silicon dioxide film.Silicon dioxide film 3 forms by for example chemical vapor deposition (CVD) or sputter.Amorphous silicon film 4 forms by for example low pressure chemical vapor deposition (LP-CVD) or plasma-enhanced CVD (PE-CVD).
Pulse energy density distribution 5 along short-axis direction in the beam cross section can be similar to by Gaussian Profile.Amorphous silicon film 4 has applied fusion fully on the zone 6 of laser beam that pulse energy density is equal to or higher than the critical value Eth that can make the complete fusion of amorphous silicon one." fully " speech refers to that silicon fiml all is melted on whole thickness.
In the zone 12 of the pulse energy density outside the zone 6 between critical value Eth and value Ec, the silicon fiml partial melting." part " also exists a part of silicon fiml not have fusion also still to keep amorphous phase although a speech refers to a part of silicon fiml to be melted.In the zone 9 outside pulse energy is the position of Ec, amorphous silicon film 4 does not have fusion.When the silicon of fusion solidifies, form silicon crystal grain.
The inventor has found following phenomenon.Formed relatively large crystal grain near the position of pulse energy density critical value Eth the belt-like zone 7, in the zone 8 of belt-like zone 7 inside, formed small grains, crystal grain random distribution in zone 12, the crystal grain of zone in 12 has crystallite dimension in zone 8 and the medium size between the crystallite dimension in the zone 7, and phrase " crystallite dimension " refers to be distributed in the average-size of the crystal grain in each zone.
Fig. 2 B is the schematic diagram that applies the zone of pulse laser beam.Vertical direction among Fig. 2 B is corresponding with the major axis of beam feeding sputtering area.Belt-like zone 7 is at center line 11 with along between the border 10 that the major axis of beam feeding sputtering area extends.The border 10 of belt-like zone 7 and beam feeding sputtering area from a distance.A plurality of crystal grain 13 are formed and line up chain along long axis direction.
Intensity distributions along the pulse laser beam of short-axis direction can be approximate with Gaussian Profile.Half breadth along the intensity distributions of minor axis is called width of light beam here.With the corresponding beam component in the skirt section of Gaussian Profile in fact also be applied to surface of the work on two outsides in the corresponding zone of width of light beam on.The border 10 of beam feeding sputtering area for example can be defined as, and pulse energy density becomes peaked position at 10% o'clock.
Fig. 3 is the sketch of being delineated out by the electron scanning micrograph of polycrystallization silicon fiml (SEM photo).The incident pulse laser beam is that second harmonic (wavelength of 527nm or 524nm) and its pulse duration of Nd:YLF laser is 100ns.Length at the beam cross section of surface of the work upper edge long axis direction is 5mm, and width of light beam is 0.2mm.
Applied two pulse laser beams simultaneously to the same area, their pulse energy densities on surface of the work are 500mJ/cm
2Therefore the effective impulse energy density is 1J/cm
2Pulse energy density calculates divided by the beam cross section area on the surface of the work with pulse energy.
Can see that formed relatively large crystal grain in belt-like zone 7, this big crystal grain is lined up chain along long axis direction.The length of each crystal grain is approximately 1.5-2 μ m along short-axis direction, is approximately 0.7-1.5 μ m along long axis direction.A plurality of fine grains have been formed in the zone 8 between two belt-like zones 7.
Can see that in the zone 12 outside belt-like zone 7, crystal grain is random distribution, size is greater than the fine grain in the zone 8 and less than the crystal grain in the belt-like zone 7.The zone 9 that is positioned at outside the random distribution grained region 12 still keeps amorphous phase.By microscopic examination, can find border between these zones by color distortion.
Below, will describe how forming the Study on Mechanism with crystal grain of different size shown in Figure 3.
Fig. 4 A is the graph of a relation of the speed of growth of temperature and silicon crystal, and Fig. 4 B is the graph of a relation of the required nucleus formation rate of temperature and crystal growth.The ordinate of Fig. 4 A is represented the speed of growth, and unit is " m/s ", and the ordinate of Fig. 4 B is represented the nucleus formation rate, and unit is " 1/cm
3S ", the abscissa representation temperature of Fig. 4 A and 4B, unit are " K ".Figure shown in Fig. 4 A and the 4B is with Daiji ICHISHIMA (Sumitomo Heavy Industries, Ltd) at the material of 21st FEM seminar, vol.22, pp.27-32, the Simulation Integration System Sectional Committee, TheJapan Society for Technology of Plasticity, " MicroAnalysis of Dynamic Crystal Growth Process of Polycrystal " method described in the July 14,1999 is drawn.
Shown in Fig. 4 A, locating the speed of growth at the fusing point (1683K) of monocrystalline silicon is 0, and along with the reduction of temperature, the speed of growth increases.Near the temperature of 1500K, the speed of growth reaches maximum.Therefore, the temperature of molten silicon is low more, and the speed of growth is also just fast more.The speed of growth also depends on the temperature gradient at the interface between solid phase and the liquid phase, and temperature gradient is steep more, and the speed of growth is fast more.
Shown in Fig. 4 B, along with temperature reduces from the silicon fusing point, it is big that the nucleus formation rate becomes, and reach maximum near the temperature of 600K.
Belt-like zone 7 shown in Figure 3 is considered to have proper temperature that the low nucleus formation rate and the high speed of growth can be provided and provides suitable temperature gradient at the solid-liquid phase interface place.Zone 12 between belt-like zone 7 and amorphous area 9 is considered to because its temperature is lower than belt-like zone 7, thus have high nucleus formation rate, and since mild in solid-liquid phase interface place temperature gradient, so have the slower speed of growth.Can think that the crystal grain in this zone can not become greatly, because formed a plurality of nucleus before grain growth.
Can think,,, form so nucleus is an explosion type, and the formation of nucleus more be occupied an leading position than the speed of growth because temperature is low in fine grained region territory 8.When temperature was reduced to the temperature that the nucleus formation rate uprises suddenly, the crystal growths in the belt-like zone 7 were subjected to the obstruction of newly-generated nucleus, and crystal growth stops.The position that crystal growth stops to be considered to the boundary between belt-like zone 7 and fine grained region territory 8.
More particularly, can think, in zone 12, come the crystal growth (non-homogeneous growth) of the formed nucleus at the interface between comfortable melting layer and the lower floor to become leading, and in fine grained region territory 8, come the crystal growth (evenly growth) of formed nucleus in the comfortable melting layer to become leading.Big crystal grain is considered to along non-homogeneous growth-dominated zone and the evenly formation of the boundary between the growth-dominated zone.
For forming big crystal grain, melt region must be set for proper temperature gradient and the temperature that the quick speed of growth and low nucleus formation rate can be provided.If temperature gradient is very steep in the belt-like zone shown in Fig. 2 A, then keep the zone of proper temperature to narrow down, be difficult to form big crystal grain.For forming big crystal grain, preferably make near belt-like zone 7 pulse energy densities distribute mild.
If the gradient that pulse energy density distributes is too steep, then the nucleus formation rate increases.On the contrary, if the gradient that pulse energy density distributes is peaceful slow, then the speed of growth reduces.Therefore, think to have the both not too steep also not too mild scope of some pulse energy density distribution gradients, to set proper temperature and the proper temperature gradient that the quick speed of growth and low nucleus formation rate can be provided at the solid-liquid phase interface place.
Below, with reference to Fig. 5 preferred pulse energy density distribution curve is described.
Fig. 5 A has shown the relation between the width of light beam on crystallite dimension and the surface of the work.The abscissa unit of representative is the width of light beam of " μ m ", and the ordinate unit of representative is the crystallite dimension of " μ m ".Crystallite dimension is used disclosed crystal growth mensuration program calculating among the Japanese patent application JP 2001-297983.
Workpiece is thick silicon dioxide film of 100nm and the thick amorphous silicon film of 50nm that is formed on the described silicon dioxide film.At the pulse laser beam wavelength is that 527nm and pulse duration (half breadth) are under the condition of 140ns, be that simulate in zone in the beam feeding sputtering area of 6 μ m to overall width, wherein being positioned at pulse energy density and being half the width in the outside of position of peak value is 1 μ m, and being positioned at pulse energy density and being half the width of inboard of position of peak value is 5 μ m.This setting is based on the pulse energy density distribution gradient and becomes half position of peak value at pulse energy density and reach about maximum, and has formed big crystal grain in this zone.
Beam feeding sputtering area is set for along the intensity distributions of short-axis direction has Gaussian Profile.Under different peak strengths to four beam cross section width: 5.0 μ m, 8.3 μ m, 16.7 μ m and 83.0 μ m simulate respectively.Crystallite dimension under the condition that forms maximum crystal grain is used as the crystallite dimension under this width of light beam.In the pulse energy density maximum is 1100mJ/cm
2, 1400mJ/cm
2, 1500mJ/cm
2And 1500mJ/cm
2Condition under, when the beam cross section width is 5.0 μ m, 8.3 μ m, 16.7 μ m and 83.0 μ m, formed maximum crystal grain respectively.
Fig. 5 B has shown that crystallite dimension and pulse energy density are the relation of the pulse energy density distribution gradient at half place of peak strength.Fig. 5 B is that the pulse energy density distribution gradient by each measuring point place shown in the calculating chart 5A forms.
Shown in Fig. 5 B, along with pulse energy density distributes from 20mJ/cm
2/ μ m raises, and crystallite dimension increases gradually.This can be owing to rate of crystalline growth faster.But crystalline size is 170mJ/cm at the pulse energy density distribution gradient
2Reach maximum near the/μ m, along with gradient variable must be worth greater than this, crystal grain diminishes.This can be owing to because pulse energy density gradient steepening, the temperature gradient at solid-liquid phase interface place also steepening and laterally the dissipation of heat speed of growth is increased.That is, can think owing to not reaching the crystal growth time of abundant length, so before crystal is grown up, formed a plurality of nucleus.
When forming polycrystal film shown in Figure 3, be 500mJ/cm at pulse energy density
2The gradient of position be 13mJ/cm
2/ μ m.Along short-axis direction, the crystallite dimensions in the belt-like zone shown in Figure 37 are about 1.5-2 μ m, with the trend of the analog result shown in Fig. 5 B much at one.In gradient is 18mJ/cm
2Under the situation of/μ m, obtained and the analog result trend much at one shown in Fig. 5 B.If at pulse energy density is 500mJ/cm
2The gradient at place is 10mJ/cm
2/ μ m or steeper then can expect can obtain and analog result trend much at one shown in Fig. 5 B.
Can judge that by the analog result shown in Fig. 5 B for forming big crystal grain, preferably the pulse energy density distribution with belt-like zone 7 places shown in Fig. 2 A and the 2B (more strictly speaking, being the external boundary place of belt-like zone 7) is set at 280mJ/cm
2/ μ m or milder.Equally preferably gradient is set at 10mJ/cm
2/ μ m or steeper.Use the thick amorphous silicon film of 100nm to carry out similar simulation, and much at one trend when having obtained to be 50nm with thickness.
In first embodiment, shown in Fig. 2 B, applied the higher laser beam component of intensity that is positioned at the skirt section to the zone 12 of crystal grain random distribution.Owing to applied the higher laser beam of intensity in zone 12, this regional temperature raises.Therefore, the temperature gradient at the temperature of belt-like zone and solid-liquid phase interface place satisfies the condition that is suitable for forming big crystal grain.Preferably the width setup with zone 12 is 12-15 μ m or wideer, increases effect to obtain enough crystallite dimensions.
Describe with reference to the relation between Fig. 6 pulse-width and the crystallite dimension below.
Fig. 6 has shown the relation between crystallite dimension and the pulse duration.The abscissa unit of representative is the pulse duration of " ns ", and the ordinate unit of representative is the crystallite dimension of " μ m ".Crystallite dimension uses the crystal grain mensuration program of above being quoted to calculate.
Workpiece and the pulse laser beam wavelength condition when describing with reference to Fig. 5 is identical.Width of light beam on the surface of the work is set at 16.7 μ m.Analogy method used method when describing with reference to Fig. 5 is similar.
Be appreciated that when pulse duration broadens it is big that crystallite dimension becomes.This can be owing to when pulse duration broadens, and decrease of temperature becomes gently, so melt region is remained on suitable temperature more of a specified durationly.But if pulse duration broadens under the condition of isopulse energy, then the peak strength of pulse laser beam reduces, thereby can not keep sufficient power density.Therefore, the upper limit of pulse duration is limited by the output characteristic of used lasing light emitter.
If as lasing light emitter, then pulse duration is generally 70ns or narrower with excimer laser.Usually, the pulse duration of all solid state laser such as Nd:YLF laser is 20-30ns or 100ns or wideer.For forming big crystal grain, preferably use pulse duration to be 100ns or wideer laser.
For the state of temperature that makes the silicon melt region reaches optimization, the distribution curve and the pulse duration of pulse energy density noted in above-mentioned research.State of temperature can also be by controlling being applied second pulse laser beam by zone freezing forward direction the same area of first pulse laser beam fusion.
Fig. 7 has shown an example of the waveform that is applied to the laser beam on the workpiece.Abscissa is represented the elapsed time, and ordinate is represented intensity of laser beam.Applied a pulse laser beam S1 in the t1 time and shone, applied a pulse laser beam S2 in the t2 time and shone as second road as first road.The pulse duration (half breadth) of the first and second autolyte impulse light beams is respectively PW1 and PW2.In example shown in Figure 7, although the peak strength of the second autolyte impulse light beam of setting is lower than the first autolyte impulse light beam, two peak strengths can be identical.
After having applied the first autolyte impulse light beam S1 shown in Figure 7, amorphous silicon film is melted.Along with temperature reduces, form nucleus, thereby become crystal grain by these nucleus growths.Before temperature is reduced to the big temperature of nucleus formation rate change, apply the second autolyte impulse light beam S2, to heat the same area once more.The second road laser beam suppresses nucleus and forms, thereby crystal growth can continue.Therefore can form big crystal grain.
Before solidifying fully, apply the second autolyte impulse light beam S2 by the zone of the first road laser beam incident fusion.For example, be set at about 300-1500ns the time of delay from the first road laser beam incident to the second road laser beam incident.If with all solid state laser as lasing light emitter, then can be than using the excimer laser easier control lag time.As described below, crystal grain is in case form, just than amorphous phase region more infusibility melt.Therefore, crystal grain is in case form just very difficult by the second autolyte impulse light beam incident fusion once more.
For example, be 1300mJ/cm when applying the pulse energy density peak value
2, pulse duration is 140ns and width of light beam when being the pulse laser beam of 16.7 μ m, crystallite dimension is about 2.1 μ m.By contrast, when the pulse energy density peak value at the first road laser beam be 1300mJ/cm
2, the pulse energy peaks of the second road laser beam is 700mJ/cm
2And be under the condition of 900ns after the polycrystallization time of delay, and crystallite dimension is about 4.4 μ m.Can make crystal grain become big by applying twice pulse laser beam with certain time of delay.
The method that applied the second autolyte impulse light beam before the zone freezing by the first autolyte impulse light beam fusion is known as the method for double pulse measurement at this.Say that more briefly the method that applied twice or the above pulse laser beam of twice before the silicon of fusion solidifies is known as multipulse method at this.
It is the mildest that the method for first embodiment does not use mask that intensity of laser beam is distributed.Therefore the energy utilization efficiency of laser beam can be improved.
By the method for first embodiment, can form one wherein crystal grain line up the crystal grain post of chain along first direction.Average-size at crystal grain on perpendicular to the direction of first direction can be set at 1.5 μ m or bigger.
Below, second embodiment is described, wherein the crystal grain that is formed by first embodiment further broadens on the direction (in-plane direction) in basal surface.
Fig. 8 A-8G is the schematic diagram that the crystal grain of how growing is described.Among Fig. 8 A-8G each has shown the cross section of silicon fiml, and Fig. 8 A-8G's is horizontal corresponding to the short-axis direction of pulse laser beam in incident area.
Shown in Fig. 8 A, when the method for using first embodiment applies a pulse laser beam, a plurality of crystal grain of lining up chain along long axis direction (perpendicular to the direction of drawing) in two belt-like zones 7, have been formed.In the zone between two belt-like zones 78, formed fine grain.The width of each belt-like zone 7 for example is 4 μ m.Shown in Fig. 5 A and 5B,, can form the crystal grain that size is about 4 μ m by optimization laser beam incident condition.
Fig. 8 B has shown by move laser beam incident position 15 μ m along short-axis direction and has applied crystalline state after the second road laser beam.For example, be 15 μ m if width of light beam is 100 μ m and displacement, then Duplication is 85%.
The position that the direction that moves along laser beam at belt-like zone 7 moves 15 μ m has formed the belt-like zone 20 with discontinuous crystal grain.The width of belt-like zone 20 is 4 μ m.Although amorphous silicon film, fine grain and little crystal grain in the zone between two belt-like zones 20 are melted, the big crystal grain in the belt-like zone 7 is difficult to be melted.In fact, although the crystal grain in the belt-like zone 7 by partial melting, is kept intact but still be left some crystal grain.Along with temperature reduces, crystal grain remaining in the belt-like zone 7 becomes seed crystal, thereby crystal growth takes place.
Suppose that crystal growth occurs to the measure-alike degree with the crystal grain that is formed by the first road laser beam, being grown in the crystal grain length of the both sides of belt-like zone 7 growing is about 4 μ m.Therefore, having formed width around the belt-like zone 7 that is positioned at laser beam direction of motion front side is the polycrystalline zone 7a of about 12 μ m.The width that is in belt-like zone 7a and the fine grained region territory 15 between the belt-like zone 20 of laser beam direction of motion front side is about 7 μ m.Be not melted near the amorphous silicon film, fine grain and the little crystal grain that are positioned at the belt-like zone of laser beam direction of motion rear side, therefore grain growth does not take place.
Fig. 8 C has shown by move laser beam incident position 15 μ m along short-axis direction and has applied crystalline state after the 3rd road laser beam.
The position that the direction that moves along laser beam at belt-like zone 20 moves 15 μ m has formed the belt-like zone 21 with discontinuous crystal grain.The width of belt-like zone 21 is 4 μ m.As seed crystal, grain growth has taken place further by the crystal grain of belt-like zone 20 that utilizes belt-like zone 7a and be arranged in laser beam direction of motion front side.
Formed the crystal grain of wide about 4 μ m to the rear side of moving direction from belt-like zone 7a.Simultaneously, from belt-like zone 20 to the grown crystal grain of wide about 4 μ m of the front side of laser beam moving direction.In the zone 15 between belt-like zone 7a and belt-like zone 20, from two side direction central authorities crystal growth has taken place.Because the width in zone 15 is about 7 μ m, so when 3.5 μ m were grown in crystal growth from both sides, crystal grain collided each other crystal growth is stopped.
Like this, just form a belt-like zone 7b who comprises the wide 19.5 μ m of belt-like zone 7a, also formed a belt-like zone 20a who comprises the wide 11.5 μ m of belt-like zone 20.A plurality of crystal grain of lining up chain along long axis direction in belt- like zone 7b and 20a, have been formed.Center line 16 along zone 15 has formed a grain boundary.Because crystal grain collides each other, therefore formed the projection of a mountain range shape in the position of center line 16.
Fig. 8 D has shown by move laser beam incident position 15 μ m along short-axis direction and has applied crystalline state after the 4th road laser beam.
The position that the direction that moves along laser beam at belt-like zone 21 moves 15 μ m has formed belt-like zone 22.By utilizing crystal grain in the belt-like zone 20a as seed crystal, crystal is in the front side growth along the laser beam moving direction, and by utilizing crystal grain in the belt-like zone 21 as seed crystal, crystal is in the growth of the both sides of this belt-like zone.Thus, the belt-like zone 20a of wide 15 μ m and the belt-like zone 21a of wide 11.5 μ m have been formed.
Fig. 8 E-8G has shown by at every turn moving laser beam incident position 15 μ m along short-axis direction and has applied crystalline state after the five-seven road laser beam.
The 5th road laser beam has formed a new belt-like zone 23, and belt- like zone 21a and 22 is broadened and forms belt-like zone 21b and 22a.The 6th road laser beam broadens belt- like zone 22a and 23 and forms belt-like zone 22b and 23a.The 7th road laser beam broadens belt-like zone 23a and forms belt-like zone 23b.
Like this, move along short-axis direction by the laser beam incident position at every turn and to apply laser beam repeatedly, can be with whole amorphous silicon film polycrystallization almost.
Fig. 9 is the schematic diagram according to the SEM photo of the polycrystal film of the described method manufacturing of Fig. 8 A-8G.Can observe a plurality of belt-like zones 25.Belt-like zone 25 wide about 15 μ m, and in belt-like zone 25, formed a plurality of crystal grain of lining up chain along long axis direction.Boundary between the adjacent banded regions territory 25 has formed the projection 26 of mountain range shape.
Below, with reference to Figure 10, the condition that makes whole amorphous silicon film polycrystallization is described.Because Duplication reduced when the pulse laser incoming position moved, so the width in the fine grained region territory 15 shown in Fig. 8 B broadens.In this case, sending area 15 before the crystal grain of regional both sides growth thus collides each other, laser beam incident zone.In addition, even Duplication remains unchanged, if the length of crystal growth shortens under the per pass laser beam, then also same phenomenon can take place.Therefore, if the crystal growth length under the per pass laser beam irradiation is very short, then require Duplication very high.
Figure 10 has shown crystal growth length under the per pass laser beam irradiation and the relation between the required Duplication.Abscissa is represented the crystal growth length under the per pass laser beam irradiation, and unit is " μ m ", and ordinate is represented Duplication, and unit is " % ".For example, if the crystal growth length under the per pass laser beam irradiation is 10 μ m, then Duplication is set at 70% or higher.Clearly, when the crystal growth length under the per pass laser beam irradiation shortens, the required Duplication of whole amorphous silicon film polycrystallization is uprised.
For making whole amorphous silicon film polycrystallization, Duplication should be set at the center line 16 that makes fine grained region territory 15 and remain on by the silicon melt region of laser beam incident fusion and bump against each other until crystal grain shown in Fig. 8 B from 15 both sides, fine grained region territory growths.
Below, with reference to Figure 11 the optimal wavelength of the laser beam that is used for making the amorphous silicon film polycrystallization is described.
Figure 11 has shown the relation of the absorption coefficient of light of wavelength and amorphous silicon and monocrystalline silicon.Abscissa is represented wavelength, and unit is " nm ", and ordinate is represented absorption coefficient, and unit is " * 10
7Cm
-1".Black circle among Figure 11 and white circle are represented the absorption coefficient of monocrystalline and the absorption coefficient of amorphous silicon respectively.
As can be seen, in wavelength was equal to and greater than the scope of about 340nm, the absorption coefficient of amorphous silicon was bigger than monocrystalline silicon.In 400-600nm and other wave-length coverage, the absorption coefficient of amorphous silicon is than the big numerical digit of monocrystalline silicon or more.If formerly the crystal grain of Xing Chenging is used as the seed crystal of crystal growth, then preferably under the situation of fused grain not, make the amorphous area fusion.The actual zone that crystal grain distributed that forms is not monocrystalline but amorphous silicon.The absorption coefficient of polysilicon depends on the size of crystal grain, and its numerical value is in the centre of monocrystalline and amorphous silicon.Along with crystallite dimension becomes big, the absorption coefficient of polysilicon becomes near monocrystalline, and along with crystallite dimension diminishes, the absorption coefficient of polysilicon becomes near amorphous silicon.
Therefore, preferably use wavelength to be equal to or greater than the pulse laser beam of 340nm, with the non-crystalline areas 9 shown in preferential fusion Fig. 2 B, random distribution zone 12 and fine grained region territory 8, and the big crystal grain in the not fusion belt-like zone 7.Therefore, absorption coefficient can reduce if wavelength is oversize, so preferably use wavelength to be 900nm or shorter pulse laser.
In the wave-length coverage (about 308nm) of excimer laser, the absorption coefficient of amorphous silicon is than the height in the 340-900nm wave-length coverage.Therefore, only in the superficial layer of amorphous silicon film, absorb, and produce temperature gradient at thickness direction.If use the laser beam of 340-900nm wave-length coverage, then laser beam enters relative darker zone in the amorphous silicon film, thereby film can evenly be heated on thickness direction.Can form the crystal of better quality thus.
Below, with reference to Figure 12 A and 12B the polycrystalline film manufacture method of the 3rd embodiment is described.
Figure 12 A has shown polycrystallization zone and the relation of the laser beam that is applied along the pulse energy density distribution of short-axis direction.In the zone 35 that has applied laser beam, formed thin crystalline substance with high impulse energy density.Formed in 35 both sides, zone and to have had belt-like zone 30A and the 30B that lines up the big crystal grain of chain along long axis direction.Width of light beam is set like this, so that the width in fine grain zone 35 approximates the width of one of belt- like zone 30A and 30B.
The second road laser radiation is to carry out along the distance that the width of short-axis direction equates by the laser incoming position being moved with belt-like zone 30A.
Shown in Figure 12 B, between belt-like zone 30A that has formed crystal grain and 30B, formed belt-like zone 31A with big crystal grain of lining up chain.Simultaneously, the front side at the belt-like zone 30B that is positioned at laser beam direction of motion front side has formed belt-like zone 31B.
Like this, four belt- like zone 30A, 31A, 30B and 31B have been formed by the twice laser beam.The crystal grain in adjacent banded regions territory contacts with each other.By repeating similar step, the whole zone of film all can be by polycrystallization.
According to temperature conditions, can carry out crystal growth as seed crystal by utilizing the crystal grain in belt-like zone 30A and the 30B, rather than by the nucleus generation grain growth that forms in the zone shown in Figure 12 A 35.
Below, with reference to Figure 13 A and 13B, the polycrystalline film manufacture method of the 4th embodiment is described.
Figure 13 A has shown polycrystallization zone and the relation of the laser beam that is applied along the pulse energy density distribution of short-axis direction.Formed in the both sides that pulse energy density reaches peaked position and to have had belt-like zone 36A and the 36B that lines up the big crystal grain of chain along long axis direction.Because width of light beam is narrow, the crystal grain that is formed by the nucleus in the belt-like zone 36A contacts with the crystal grain that is formed by the nucleus in the belt-like zone 36B.Has a grain boundary along contact wire 38.
The second road laser radiation is to carry out along the distance that the width of short-axis direction equates by the laser incoming position being moved with belt- like zone 36A and 36B.
Shown in Figure 13 B, the belt-like zone 37A and the 37B that contact with each other have been formed.The belt-like zone 37A that is positioned at laser beam direction of motion rear side contacts with the belt-like zone 36B that is positioned at laser beam direction of motion front side that is formed by the first road laser beam.By repeating similar step, the whole zone of film all can be by polycrystallization.
In third and fourth embodiment,, then can form big crystal grain if the pulse energy density distribution design of the pulse laser beam of irradiation is become to have the described suitable shape with reference to first embodiment.In addition, as shown in Figure 7, if the twice pulse laser beam is applied to the same area, then grain growth gets bigger.
Below, with reference to Figure 14 and Figure 15 A-15C, the polycrystalline film manufacture method of the 5th embodiment is described.
Figure 14 has shown the cross-sectional view of workpiece 1 of close laser beam incident position and an example that distributes along the pulse energy density of beam cross section short-axis direction.Pulse energy density obtains divided by the beam cross section area of surface of the work with pulse energy usually.Strictly speaking, the pulse energy density that calculate to obtain thus is the mean value in beam cross section.Because the intensity of laser in beam cross section is uneven, so pulse energy density also is uneven.If with the distribution of Gaussian Profile approximate evaluation light intensity, then pulse energy density distributes and also is similar to Gaussian Profile.
As shown in figure 14, similar with first embodiment that reference Fig. 2 A is illustrated, workpiece is one and has the silicon dioxide film 3 on substrate of glass of being formed on 2 and the laminate substrate of amorphous silicon film 4.The incoming position of pulse laser beam moves right by shown in Figure 14.
Pass the part of the laser beam of homogenizer 72 shown in Figure 1 and tackled by light shielding plate 18, the remainder of laser beam incides on the amorphous silicon film 4 through optical focusing system 19.Light shielding plate 18 interceptions are positioned at along the light in the skirt section that the pulse energy density of beam cross section short-axis direction distributes.The beam cross section that optical focusing system 19 will be positioned at light shielding plate 18 present positions focuses on the surface of amorphous silicon film 4.Focusing on multiplication factor for example is 1.
If do not use light shielding plate 18, then be similar to the pulse energy density distribution of Gaussian Profile to the surperficial upper edge pulse laser beam short-axis direction of amorphous silicon film 4.That is, it is intensive that pulse energy density is distributed in the central area, and weaken to borderline region.Pulse energy density distributes and needn't have Gaussian Profile, and it can be a central area overall distribution intensive and that weaken to boundary.
The pulse energy density that light shielding plate 18 interceptions are positioned at the skirt section of laser beam incident position direction of motion rear side is equal to or less than E
HA part of pulse laser beam.In the front side, pulse energy density less than or be lower than E
LA part of pulse laser beam conductively-closed.Pulse energy density E
LBe lower than E
H
In a concrete instance, light intensity does not become 0, just tackled by light shielding plate 18 at the boundary of beam cross section, but beam cross section is outwards widened about 6 μ m from intercepting position.The border of beam cross section is defined as 20% the position that light intensity reaches peak value.
Applied the pulse laser beam that has this pulse energy density distribution together to amorphous silicon film 4.Amorphous silicon film 4 is applying fusion on the zone of a part of laser beam that impulse density is equal to or greater than the critical value that makes the complete fusion of amorphous silicon film.If pulse energy density E
LBe equal to or greater than this critical value, the whole zone that has then applied pulse laser beam all is melted.During the melt region cooling, crystal grows into inside from the border of melt region.
Shown in Figure 15 A, the border of impulse light beam incoming position direction of motion rear side has formed a plurality of crystal grain 100a that arrange along the beam cross section long axis direction along the pulse, and has formed a plurality of crystal grain 101a along the border of front side.Formed in the zone between the zone of zone that forms crystal grain 100a and formation crystal grain 101a and be similar to regional 8 fine grain shown in Figure 3.The length of the crystal grain of growth depends on the temperature of melt region and the temperature gradient at solid-liquid phase interface place.The temperature of rear side boundary and temperature gradient are different with the front side boundary.Therefore the length of the crystal grain of growing from two borders of melt region is different.
If the temperature of rear side boundary and temperature gradient satisfy the condition that is suitable for crystal growth, the crystal grain 100a that then is formed at the rear side boundary is bigger than the crystal grain 101a that is formed at the front side boundary.For example, the lateral dimension that is formed at the crystal grain 100a of rear side boundary can reach 7-8 μ m.
Then, move the pulse laser beam incoming position by short-axis direction and apply another autolyte impulse light beam along beam cross section.The displacement of incoming position is set to make the second road laser beam to contact with crystal grain 100a on the border of beam cross section rear side or is overlapping.The crystal grain 101a that is positioned at the front side boundary that is formed by the first road laser beam is by the second road laser beam fusion.
Shown in Figure 15 B, by the rear side boundary in the zone of the second road laser beam fusion, crystal forms the big crystal grain 100b that comprises crystal grain 100a by utilizing crystal grain 100a as seeded lateral growth.If the rear side border of the beam cross section of the second autolyte impulse light beam contacts with crystal grain 100a, then the lateral dimension of crystal grain 100b is 14-16 μ m, is about the twice of the size of crystal grain 100a.
By the incoming position repetition pulse laser beam irradiation of mobile pulse laser beam, so that it is overlapping with the area part that applies down laser beam to be applied with the zone of one laser beam.The displacement of incoming position is configured such that the rear side border of the beam cross section of next autolyte impulse light beam contacts with the rear side crystal grain that is formed by last autolyte impulse light beam or is overlapping.
Shown in Figure 15 C, the crystal grain cross growth forms big crystal grain 100c.The little crystal grain 101b of the front side boundary that is formed at beam cross section shown in Figure 15 B is by next light beam fusion of autolyte impulse and elimination.
In the 5th embodiment, crystal is from the rear side border growth of the beam cross section that limited by light shielding plate 18.In first embodiment, the belt-like zone with big crystal grain 7 of formation has zigzag manner as shown in Figure 3.Among the 5th embodiment, the zone that forms crystal grain 100a has rectilinear form usually by light shielding plate 18 artificial decisions, and the belt-like zone with discontinuous crystal grain 100a does not have zigzag manner.Therefore, can determine the position of the second autolyte impulse light beam at an easy rate, so that the contact of the rear side border of beam cross section has the belt-like zone of discontinuous crystal grain 100a.
In addition, crystal growth direction can be with consistent perpendicular to the direction of beam cross section major axis.When on polycrystal film, forming active element, make the sense of current of active element parallel, can suppress carrier mobility thus and be reduced by the grain boundary with crystal growth direction.
All mobile incoming position when in this embodiment, whenever applying one pulse laser beam.As the explanation that reference Fig. 7 is done, can adopt the method for double pulse measurement to apply the twice pulse laser beam to the same area.Use the method can make the size of crystal grain become big.
Preferably the zone in the pulse energy density distribution skirt section as shown in figure 14 that will be fallen by light shield (is the preferred value E of pulse energy density
HAnd E
L) can determine by a plurality of determination experiments under different light shield area sizes (width).
Below, will be described the actual determination experiment that carries out.Come the laser beam output of self-excitation light source to be shaped as to have the elongate light beam of the wide and beam cross section that 17mm is long of 100 μ m.The both sides of beam cross section are all fallen by the light shielding plate light shield, and forming the cross section of wide 22 μ m, and this beam cross section focuses on the surface of amorphous silicon film.The width of beam cross section is corresponding with the half breadth of light distribution.
Adopted the method for double pulse measurement under the condition of using two lasing light emitters, the pulse energy density of the first and second autolyte impulse light beams is set at 550mJ/cm respectively
2And 500mJ/cm
2, be set at 100ns time of delay.
Under these conditions, applied the twice pulse laser beam, the width that is formed at the crystal grain 101a on the scanning direction of beam cross section rear side is 3.1 μ m.By using the surface of pulse laser beam with the spacing scanning amorphous silicon film of 3 μ m, crystal can be along the growth of scanning direction continuous crystallisationization ground shown in Figure 15 C.The orientation of crystal grain is determined.Each crystal grain＜110〉direction all consistent with the direction that is parallel to crystal growth direction (scanning direction).
Below, with reference to Figure 16 and Figure 17 A-17C, the polycrystalline film manufacture method of the 6th embodiment is described.
As shown in figure 16, in the 6th embodiment, in the front side of the pulse laser beam incoming position direction of motion, a part of pulse energy density is equal to or less than E
HThe skirt section tackled by light shielding plate 18, and at rear side, a part of pulse energy density is equal to or less than E
LThe skirt section tackled by light shielding plate 18.
Shown in Figure 17 A, use irradiation together, on the border of beam cross section front side, formed relatively large crystal grain 110a, on the border of rear side, formed less relatively crystal grain 111a.
Shown in Figure 17 B, when the incoming position by mobile pulse laser beam carries out the irradiation of another road, crystal grain 110b and 111b have been formed.Because relatively large crystal grain 110a is difficult to fusion, so they are hardly by second road and laser beam fusion subsequently.Crystal grain 110b grows to rear side (to crystal grain 110a side) from the border of melt region front side.When crystal grain 110a was touched on the top of crystal growth, crystal growth stopped.
In this case, by utilizing the crystal grain 110a that has formed as seed crystal, lateral crystal growth has taken place.Therefore, the moving interval of pulse laser beam incoming position can be longer than the width of crystal grain 110a.
Shown in 17C, by the incoming position of mobile pulse laser beam, the repetition pulse laser beam irradiation is to form relatively large crystal grain 110a-110e.In Figure 17 C, the 3rd road laser beam forms less relatively crystal grain 111c at the boundary of beam cross section rear side.In the 4th road and laser beam irradiation subsequently, because the border of beam cross section rear side is positioned within the relatively large crystal grain 110a-110e, so near the rear side border, do not form melt region.
In the 6th embodiment, shown in Figure 17 C, for example, at belt-like zone with have between the belt-like zone of discontinuous crystal grain 110b and formed a border clearly with discontinuous crystal grain 110a.The position on this border can manually determine by using light shielding plate 18.For example, when on polysilicon film, forming active element, can set the position of grain boundary, so that active element is not overlapping with the grain boundary.In the above described manner, whole substrate surface all can cover with belt-like zone, as shown in Figure 9.
Below, the actual determination experiment that carries out is described.Come the laser beam output of self-excitation light source to be shaped as to have the elongated shape light beam of the wide and beam cross section that 17mm is long of 100 μ m.The beam cross section border of front side, scanning direction is fallen by the light shielding plate light shield, forms the cross section of wide 55 μ m, and this beam cross section focuses on the surface of amorphous silicon film.Adopted the method for double pulse measurement under the condition of using two lasing light emitters, the pulse energy density of the first and second autolyte impulse light beams is set at 710mJ/cm respectively
2And 640mJ/cm
2, be set at 200ns time of delay.
Under these conditions, applied the twice pulse laser beam, the width that is formed at the crystal grain 110a on the scanning direction, beam cross section front side is 5.4 μ m.By with the surface of pulse laser beam, formed the belt-like zone of wide 12 μ m and on the long axis direction of beam cross section, lined up the crystal grain of chain with the spacing of 12 μ m scanning amorphous silicon film.The crystal grain in adjacent banded regions territory is in the boundary contact of belt-like zone, and whole zone all can be by polycrystallization.
Although the crystal grain width that is formed by one laser beam irradiation is 5.4 μ m, the width of the final belt-like zone that forms is 12 μ m.This be attributable to use the width that forms by one laser beam irradiation be the crystal grain of 5.4 μ m as seed crystal, lateral crystal growth has taken place by following one laser beam irradiation.Crystal growing process described in this crystal growing process and Fig. 8 A-8G is similar.
In the determination experiment of the 5th and the 6th embodiment, adopted the double irradiation method.Preferably will be set at 100-1000ns from the time of delay that the first autolyte impulse light beam incides the second autolyte impulse light beam incident.This preferred time of delay is short slightly when ratio does not use light shielding plate.This is because the gradient of light distribution is all very steep in the both sides of beam cross section, and setting rate is also fast when not using light shielding plate.
Below, the 7th embodiment is described.In the 5th and the 6th embodiment, the part laser beam is tackled by light shielding plate, thereby makes light distribution (or pulse energy density distribution) asymmetric on the Width of beam cross section.Can the intercepting laser bundle, so that the light distribution symmetry.Under the situation of light distribution symmetry, the boundary of side can form and have the crystal grain of size much at one before and after the scanning direction.Therefore, amorphous silicon film can be used and the 3rd embodiment shown in second embodiment shown in Fig. 8 A-8G, Figure 12 A and the 12B and the similar method polycrystallization of the 4th embodiment shown in Figure 13 A and the 13B.
In above-mentioned the 5th-Di seven embodiment, although the beam cross section at light shielding plate place is focused on the amorphous silicon film surface, light shielding plate can be arranged near the amorphous silicon film.Distance between light shielding plate and the amorphous silicon film can be about 0.1mm.
In the 5th and the 6th embodiment,,, also can form asymmetric light distribution by other optical system to form a light distribution asymmetric laser beam on the Width of beam cross section although the part laser beam is tackled by light shielding plate.For example, can insert a gradual change filter in light path, it has the dot pattern that is formed on lip-deep chromium of quartz glass (Cr) etc.
Invention has been described with reference to preferred embodiment above.But the present invention is not limited in the foregoing description.For a person skilled in the art, apparent, can carry out various modifications, improvement and combination etc. to it.
Claims (6)
1. polycrystalline film manufacture method may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface;
(b) apply at least one pulse laser beam to this film, this pulse laser beam has the elongated shape beam cross section in the direction in this film surface upper edge, and the light distribution along the short-axis direction of beam cross section has in the central area strong, asymmetric first shape that weakens to the border, described pulse laser beam by fall with a mask light shield along equal during the minor axis of beam cross section has the light distribution of central area shape strong and that weaken towards the border or be weaker than first light intensity one first skirt section a part not light shield fall that the part in one second skirt section or light shield fall to equal or the mode of a part that is weaker than second skirt section of one second light intensity obtains, a little less than described first light intensity of wherein said second beam intensity ratio;
(c) incoming position of mobile pulse laser beam and at least one in the workpiece, so that the incoming position of the pulse laser beam direction that long axis direction with the beam cross section of pulse laser beam intersects in the surperficial upper edge of film moves, and make the zone that has applied one pulse laser beam overlapping with the area part that applies last autolyte impulse light beam;
(d) apply at least one pulse laser beam to this film, this pulse laser beam has the light distribution of this first shape; And
(e) replace repeating step (c) and step (d).
2. polycrystalline film manufacture method according to claim 1 is characterized in that:
In step (b), a plurality of crystal grain of lining up chain along the long axis direction of beam cross section from the border of the beam cross section of first skirt section, one side towards growth inside one segment length of beam cross section;
In step (c), the incoming position of pulse laser beam has experienced one and has relatively moved on film, wherein the front side of moving direction is pointed in second skirt section of beam cross section, and displacement is that the border of the beam cross section of first skirt section, one side is come in contact or overlapping distance with the crystal grain of being grown from the border of first skirt section, one side of beam cross section by preceding laser beam; And
In step (d), by utilizing crystal grain by preceding one laser beam growth as seed crystal, the growth inside crystal from described seed crystal towards beam cross section.
3. polycrystalline film manufacture method according to claim 1 is characterized in that:
In step (b), towards growth inside one segment length of beam cross section, described crystal grain is lined up chain along the long axis direction of beam cross section to a plurality of crystal grain from the border of the beam cross section of first skirt section, one side;
In step (c), the incoming position of pulse laser beam moves on film, and wherein the front side of moving direction is pointed in second skirt section of beam cross section; And
In step (d), the pulse energy density of the pulse laser beam that is applied on film surface is configured such that the crystal grain that is formed in described first skirt section one side by preceding autolyte impulse light beam not by fusion once more, and forms the crystal grain that a plurality of long axis directions along beam cross section are lined up chain by the border from the beam cross section of first skirt section, one side to growth inside one segment length of beam cross section.
4. polycrystalline film manufacture method according to claim 3, it is characterized in that, in step (c), the distance that the displacement of the incoming position of described pulse laser beam comes in contact with the crystal grain by preceding laser beam growth for the crystal grain that makes growth in step (d).
5. polycrystalline film manufacture method may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface;
(b) apply at least one pulse laser beam to this film, this pulse laser beam has the elongated shape beam cross section in the direction in this film surface upper edge, and the light distribution along the short-axis direction of beam cross section has first shape that obtains by at least the first skirt portion of falling light distribution with a mask light shield, and this light distribution is strong and weaken towards the border in the central area;
(c) incoming position of mobile pulse laser beam and at least one in the workpiece, so that the incoming position of the pulse laser beam direction that long axis direction with the beam cross section of pulse laser beam intersects in the surperficial upper edge of film moves, and make the zone that has applied one pulse laser beam overlapping with the area part that applies last autolyte impulse light beam;
(d) apply at least one pulse laser beam to this film, this pulse laser beam has the light distribution of this first shape; And
(e) replace repeating step (c) and step (d).
6. polycrystalline film manufacture method may further comprise the steps:
(a) prepare the workpiece that has the film of making by amorphous material on the surface; And
(b) apply pulse laser beam to this film, with with this film fusion, this pulse laser beam has the elongated shape beam cross section in the direction in the surperficial upper edge of this film, this film is solidified, in first belt-like zone, to form crystal grain, this first belt-like zone extends along the long axis direction of beam feeding sputtering area, and be in the beam feeding sputtering area in the zone between the border of heart line wherein and the beam feeding sputtering area that extends along long axis direction, and with described border and center line from a distance, and form a random distribution zone that contacts with first belt-like zone in the portion of external zone of first belt-like zone, the crystal grain in this random distribution zone is random distribution and less than the crystal grain that forms in first belt-like zone.
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| JP2002314735 | 2002-10-29 | ||
| JP2002314735 | 2002-10-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2003801024215A Division CN100378919C (en) | 2002-10-29 | 2003-10-14 | Crystalline film and its manufacture method using laser |
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| CN101145518A CN101145518A (en) | 2008-03-19 |
| CN100514561C true CN100514561C (en) | 2009-07-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2003801024215A Expired - Fee Related CN100378919C (en) | 2002-10-29 | 2003-10-14 | Crystalline film and its manufacture method using laser |
| CNB2007101423450A Expired - Fee Related CN100514561C (en) | 2002-10-29 | 2003-10-14 | Crystalline film and its manufacture method using laser |
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| CNB2003801024215A Expired - Fee Related CN100378919C (en) | 2002-10-29 | 2003-10-14 | Crystalline film and its manufacture method using laser |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP4211939B2 (en) |
| KR (1) | KR100685141B1 (en) |
| CN (2) | CN100378919C (en) |
| TW (1) | TWI240957B (en) |
| WO (1) | WO2004040628A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005045209A (en) * | 2003-07-09 | 2005-02-17 | Mitsubishi Electric Corp | Laser annealing method |
| KR100713895B1 (en) * | 2006-04-06 | 2007-05-04 | 비오이 하이디스 테크놀로지 주식회사 | Method for forming polycrystalline film |
| JP5133548B2 (en) * | 2006-09-29 | 2013-01-30 | 富士フイルム株式会社 | Laser annealing method and laser annealing apparatus using the same |
| TWI633587B (en) | 2011-09-01 | 2018-08-21 | 應用材料股份有限公司 | Crystallization methods |
| WO2017120584A1 (en) * | 2016-01-08 | 2017-07-13 | The Trustees Of Columbia University In The City Of New York | Methods and systems for spot beam crystallization |
| DE102017109809B4 (en) | 2016-05-13 | 2024-01-18 | OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung | Method for producing a semiconductor chip |
| DE102017108949B4 (en) | 2016-05-13 | 2021-08-26 | OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung | Semiconductor chip |
| DE102017109812A1 (en) | 2016-05-13 | 2017-11-16 | Osram Opto Semiconductors Gmbh | Light-emitting semiconductor chip and method for producing a light-emitting semiconductor chip |
| US20200238441A1 (en) * | 2017-10-13 | 2020-07-30 | The Trustees Of Columbia University In The City Of New York | Systems and methods for spot beam and line beam crystallization |
| JP2020181923A (en) * | 2019-04-26 | 2020-11-05 | 株式会社日本製鋼所 | Manufacturing method for semiconductor film |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3301054B2 (en) * | 1996-02-13 | 2002-07-15 | 株式会社半導体エネルギー研究所 | Laser irradiation device and laser irradiation method |
| JP3204986B2 (en) * | 1996-05-28 | 2001-09-04 | ザ トラスティース オブ コロンビア ユニヴァーシティ イン ザ シティ オブ ニューヨーク | Crystallization of semiconductor film region on substrate and device manufactured by this method |
| EP0999244B1 (en) * | 1997-07-30 | 2003-10-08 | Mitsubishi Pencil Kabushiki Kaisha | Pseudoplastic water-base ball pen ink |
| KR100269312B1 (en) * | 1997-10-14 | 2000-10-16 | 윤종용 | Method for crystallization of silicon film and fabricating method for thin film transistor-liquid crystal display using the same |
| JP4454720B2 (en) * | 1998-07-13 | 2010-04-21 | 株式会社半導体エネルギー研究所 | Optical lens, beam homogenizer, laser irradiation apparatus, and laser irradiation method |
| CN1156894C (en) * | 1999-03-05 | 2004-07-07 | 精工爱普生株式会社 | Method for producing thin film semiconductor device |
| TW445545B (en) * | 1999-03-10 | 2001-07-11 | Mitsubishi Electric Corp | Laser heat treatment method, laser heat treatment apparatus and semiconductor device |
| US6368945B1 (en) * | 2000-03-16 | 2002-04-09 | The Trustees Of Columbia University In The City Of New York | Method and system for providing a continuous motion sequential lateral solidification |
| JP3352995B2 (en) * | 2000-04-14 | 2002-12-03 | 住友重機械工業株式会社 | Crystal growth evaluation method and apparatus |
-
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- 2003-10-14 JP JP2004548019A patent/JP4211939B2/en not_active Expired - Fee Related
- 2003-10-14 WO PCT/JP2003/013141 patent/WO2004040628A1/en active Application Filing
- 2003-10-14 CN CNB2003801024215A patent/CN100378919C/en not_active Expired - Fee Related
- 2003-10-14 CN CNB2007101423450A patent/CN100514561C/en not_active Expired - Fee Related
- 2003-10-14 KR KR1020057007439A patent/KR100685141B1/en not_active IP Right Cessation
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| Publication number | Publication date |
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| WO2004040628A1 (en) | 2004-05-13 |
| TW200416835A (en) | 2004-09-01 |
| CN101145518A (en) | 2008-03-19 |
| CN1708831A (en) | 2005-12-14 |
| JPWO2004040628A1 (en) | 2006-03-02 |
| KR100685141B1 (en) | 2007-02-22 |
| JP4211939B2 (en) | 2009-01-21 |
| KR20050059322A (en) | 2005-06-17 |
| CN100378919C (en) | 2008-04-02 |
| TWI240957B (en) | 2005-10-01 |
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