CN102046345A

CN102046345A - Method for processing fragile material substrate

Info

Publication number: CN102046345A
Application number: CN200980119186XA
Authority: CN
Inventors: 熊谷透; 平內裕介; 井上修一; 山本幸司
Original assignee: Mitsuboshi Diamond Industrial Co Ltd
Current assignee: Mitsuboshi Diamond Industrial Co Ltd
Priority date: 2008-04-15
Filing date: 2009-03-16
Publication date: 2011-05-04
Also published as: KR20110006678A; JP5050099B2; TW200948524A; WO2009128316A1; JPWO2009128316A1; KR101165977B1; TWI375602B

Abstract

Provided is a method for processing a fragile material substrate that enables to stably execute processes, such as complete cutting off of the substrate and forming of a deeper scribe line. A method for processing a fragile material substrate comprises a laser scribe step of relatively moving a beam spot by the first laser irradiation to heat the substrate, and cooling an immediate portion where the first beam spot has passed to form a scribe line; and a laser break step of relatively moving a second beam spot by the second laser irradiation along the scribe line and making the scribe line to penetrate further deeply or completely cutting off the scribe line. In the laser break process, a laser beam diameter incident on a polygonal mirror in the laser break step is adjusted to be smaller than an incident laser beam diameter in the laser scribe step, so that an energy distribution of the second beam spot is made to be top-hat type further than that of the first beam spot and is irradiated.

Description

The processing method of brittle substrate

Technical field

The invention relates to the mirror polygon repeated reflection laser beam of at a high speed rotation with the light beam spot shaping that essence had long axis direction on brittle substrate, scan aforementioned light beam spot along the line preset lines of on aforementioned brittle substrate, setting, utilize thermal stress to form the processing method of the brittle substrate of slight crack.

In detail, the invention relates to the line that scanning that brittle substrate is carried out light beam spot for the first time constitutes with the slight crack that forms by finite depth, carry out the scanning of light beam spot for the second time again so that the slight crack of this line deeply permeates the processing method of the brittle substrate of (below, slight crack is called infiltration in depth direction) or complete disjunction.

Be meant pottery, single crystal silicon, semiconductor crystal wafer, sapphire substrate, ceramic substrate of glass substrate, agglomerated material etc. at this so-called brittle substrate.

Background technology

At mirror polygon irradiating laser light beam to rotating at a high speed, will be after on laser beam that mirror polygon the is reflected guiding substrate, by the scope of the track while scan of 1 minute surface laser light reflected light beam of mirror polygon at a high speed repeating to be scanned, on substrate by the scope of the track while scan of a minute surface laser light reflected light beam all just like illuminated as 1 light beam spot.Therefore, will all be called " light beam spot " by the scope that a minute surface of the mirror polygon in rotating at a high speed is formed at the track while scan on the substrate.

Use mirror polygon and f θ lens to fragile material be the semiconductor crystal wafer irradiating laser with the oval-shaped light beam spot of shaping, and scan this light beam spot with the abrasion substrate after, form machined surface to the substrate surface inclination.Utilize this, make part that on semiconductor crystal wafer desire forms groove in tilted direction (normal direction of the machined surface) gasification and the laser processing device revealed (patent documentation 1) of discharging with vapor form.Machined surface utilize the processing of abrasion that the zone that light beam spot passes through is dissolved, so can damage.

On the other hand, glass substrate scanning has been shaped as elliptoid light beam spot and at the following heated substrates of melting temperature (or softening temperature), stress gradient has been produced process and also be utilized (refer to Patent Document 2, patent documentation 3, patent documentation 4) with the laser scribing that forms slight crack.

Generally speaking, be that the imaginary line (being called the line preset lines) that will be about to disjunction is set in substrate in laser scribing processing.And in for the edge of substrate at the top of line preset lines with formation initial stages such as break bar be full of cracks (triggerings), from the position of initial stage be full of cracks along line preset lines scanning light beam point and cool off point (zone that refrigerant is injected).At this moment, the result based near the Temperature Distribution generation stress gradient that takes place the line preset lines forms slight crack.

The slight crack processing end face that is processed to form with laser scribing is attractive in appearance and have outstanding end face intensity.In addition, the slight crack compared with the mechanical type processing of using break bar etc. produces can make reducing of chips of glass.

Therefore, laser scribing processing with headed by the flat-panel screens and various manufacture processes that must the disjunction glass substrate etc. etc. continue to be used.

In addition, " the finite depth slight crack " at the back side of the front end no show substrate of the crackled depth direction of slight crack that forms at the following scanning light beam point of melting temperature and slight crack arrive substrate the back side and with " perforation slight crack " (reference example such as patent documentation 2) of the direct disjunction of substrate.

Below, the cut channel that will be formed by the former " finite depth slight crack " is called line, and the branch broken string that is produced by the latter " perforation slight crack " is called full tangent line.Above-mentionedly form by different mechanisms.

Figure 14 is the profile of substrate of mechanism that show to form the slight crack of finite depth in a schematic way.That is the LASER HEATING of going ahead of the rest makes as Figure 14 (a) substrate GA that is shown in and has compression stress HR to produce.Afterwards, the cooling after the heating makes as Figure 14 (b) substrate GA surface that is shown in has tensile stress CR to produce.This moment, the mobile compression stress HR that makes of heat moved in substrate is inner, was formed with internal stress field Hin.Its result, shown in Figure 14 (c), tensile stress CR is distributed in the stress gradient that substrate surface side, compression stress HR be distributed in the depth direction of substrate inside and takes place, and forms slight crack Cr.

The condition that forms slight crack Cr with above-mentioned mechanism is the further infiltration that the compression stress field Hin that exists in substrate inside stops the past depth direction of slight crack Cr, so slight crack Cr stops before the Hin of the compression stress field of substrate inside, slight crack Cr is a finite depth in theory.Therefore, desire after must being formed in the line of the finite depth that slight crack Cr causes, is carried out break process with the complete disjunction of substrate again.On the other hand, processing end face of the line that slight crack Cr causes (concave-convex surface is very little) very attractive in appearance and rectilinear propagation are good, are desirable state as the processing end face.

Figure 15 is stereogram (Figure 15 (a)) and the plane (Figure 15 (b)) that shows the substrate that forms the mechanism that connects slight crack in a schematic way.That is the light beam spot BS of the laser beam that is scanned from the position of initial stage be full of cracks TR makes compression stress HR produce in substrate surface.Simultaneously, the cooling point CS that is positioned at the rear of light beam spot BS makes tensile stress CR produce in substrate surface.Its result forms the stress gradient of fore-and-aft direction in (line preset lines L on) on the scan line, and this stress gradient makes the power effect of substrate being split toward about along scan-line direction and forms the perforation slight crack, and substrate is by disjunction.

When forming this " perforation slight crack ", have needn't carry out break process just can be with the convenience point of substrate-cutting (cutting entirely), also have the situation of hope with processing purposes difference with this mechanism disjunction, but processing end face compared with above-mentioned line processing, the rectilinear propagation of the processing end face of full tangent line may be impaired, and the aesthetics of the end face of full tangent line (surperficial is concavo-convex) is also relatively poor compared with above-mentioned line quality.

In addition, being processed to form line with laser scribing or forming full tangent line is the thickness of slab etc. that exists with ... heating condition (optical maser wavelength, irradiation time, output energy, sweep speed, light beam spot shape etc.), cooling condition (refrigerant temperature, the amount of blowing, blow position etc.), substrate.

Generally speaking, become full tangent line easily when thicker when the thickness of slab of glass substrate is thin, the process range of processing conditions that can form line processing is less.

By above-mentioned, in desire glass substrate etc. is carried out the colory disjunction of end face and add man-hour, do not form full tangent line, be that heating condition, the cooling condition of selecting to form the mechanism of line carries out laser scribing processing, afterwards, carry out break process.

The break process method of carrying out after laser scribing processing can be utilized snap bar etc. is pressed on the mechanical type break process that line applies bending moment.During the mechanical type break process, substrate is applied macrobending moment may have the chips of glass generation.Therefore, not wishing have in the manufacture process of chips of glass generation, must form darker line as far as possible, so that only apply the just broken processing of little bending moment.

At this point, be to carry out carrying out the 2nd time laser irradiation along the line that is processed to form with laser scribing, make the more deep infiltration of slight crack (carrying out break process this moment once again) of finite depth or make slight crack infiltrate into the back side and the laser cutting of disjunction is handled (reference example such as patent documentation 2-patent documentation 4).

(patent documentation 1) TOHKEMY 2005-288541 communique

(patent documentation 2) TOHKEMY 2001-130921 communique

(patent documentation 3) TOHKEMY 2006-256944 communique

No. 2003/008352 communique of (patent documentation 4) WO

Summary of the invention

As above-mentioned, carry out forming the laser scribing processing of line with primary laser irradiation, handle with secondary laser irradiation carrying out laser cutting again, can reach the disjunction processing of the generation that suppresses chips of glass.

Yet if with laser scribing processing, that is the line that the irradiation of primary laser forms is more shallow, handles with follow-up laser cutting just to be difficult to make slight crack to arrive substrate back.Therefore, desire to handle the complete disjunction of substrate with laser cutting, it is more satisfactory to add the darker line of formation earlier in man-hour in laser scribing.

Again,, add the dark more line of formation in man-hour, handle that with follow-up laser cutting line is deepened, so more satisfactory in laser scribing even do not handle the complete disjunction of substrate with laser cutting.

But be processed to form heating condition and the cooling condition of darker line when just must change so far forming line with laser scribing if desire.Particularly, must improve laser output to increase the heat of going into that heating causes, the refrigerant amount of blowing when increasing cooling makes the fierce condition than the temperature difference that so far more is easy to generate depth direction, to be added to the stress gradient of the depth direction that substrate takes place.

Yet, if the work flow of processing in laser scribing in the past directly changes heating condition, the cooling condition of adopting the increase stress gradient, can't form darker line the 1st time laser irradiation, slight crack can directly connect substrate (become and form the mechanism that connects slight crack), forms full tangent line.That is, can be easier to form more shallow line though suitably select laser scribing to add the heating condition and the cooling condition in man-hour, desire changes to the condition fiercer a little than the condition of so far using with heating condition and cooling condition but even desire forms darker line, even but the scope of the heating condition that can set or cooling condition does not exist or exists also because of the narrow unstability of setting range, become the condition of the full tangent line of unexpected formation, be difficult to form the line more deeply of expection.

In addition, except that the problem that becomes full tangent line, also can produce the incidental problem of " going ahead of the rest " phenomenon.So-called " going ahead of the rest " is as shown in figure 16, near the top of line preset lines L, when the initial stage be full of cracks TR that is formed at top is heated by light beam spot BS, be starting point forms slight crack K in uncontrollable direction toward the place ahead of light beam spot phenomenon with the heating region that produces because of light beam spot BS.If the line along line preset lines L takes place just can't form " going ahead of the rest ", the rectilinear propagation of line can be significantly impaired.

Desire to be processed to form darker line and when making heating condition and cooling condition change into than the fiercer condition of the condition of so far using, the occurrence frequency that this kind " gone ahead of the rest " can improve in the laser scribing of carrying out the irradiation of primary laser.

At this point, the present invention can stabilize implementation and is machined in substrate with laser scribing and forms line to provide, and carrying out laser cutting again, to handle with the complete disjunction substrate or the processing method of brittle substrate that forms the processing of darker line be purpose.

Again, the processing method that does not make the generation of " going ahead of the rest " phenomenon just can form the brittle substrate of darker line or complete disjunction to provide is a purpose.

Be purpose with the processing method that the brittle substrate that can stabilize the colory disjunction processing of the end face of processing end face is provided again.

In addition, the present invention utilizes mirror polygon to form laser point to provide, and can utilize mirror polygon to adjust the Energy distribution of laser point in this laser point of scanning when carrying out laser cutting, can be purpose by the processing method of the stable laser cutting of adjustment of Energy distribution.

For solve above-mentioned problem for it the processing method of brittle substrate of the present invention be that the laser beam that penetrates from LASER Light Source with the mirror polygon repeated reflection of at a high speed rotation is to form light beam spot in brittle substrate, relatively move aforementioned light beam spot with the processing method of the brittle substrate of processing aforesaid base plate along the line preset lines of setting in aforesaid base plate, carry out following step.

At first, carry out by first light beam spot that laser irradiation is for the first time produced along the line preset lines relatively move heated substrates and immediately to first light beam spot by after the position blow refrigerant with cooling, to result from the laser scribing step of the line that stress gradient that depth direction changes constitutes with the slight crack that forms by finite depth.But,, heating-up temperature do not reach softening temperature in order to avoid substrate dissolves so being remained if substrate dissolves the processing that just can't utilize stress.

Whereby, there is the stress gradient (being called first stress gradient) that changes in depth direction to take place in the line preset lines.First stress gradient has the stress gradient of compressive stress distribution in the substrate surface side tensile stress to be arranged in the substrate private side.Utilize this first stress gradient to form the line that the slight crack by finite depth constitutes.

Afterwards, second light beam spot that laser irradiation is for the second time produced relatively moves to carry out the laser cutting step along aforementioned line (slight crack of finite depth).At this moment, be adjusted into the laser light beam diameter that the laser light beam diameter of injecting mirror polygon is injected during less than the laser scribing step.This adjustment particularly can make the beam diameter of laser beam itself dwindle, and the mechanism that adjusts beam diameter also can be set on light path.Adjust whereby, ratio when the laser beam that is irradiated to mirror polygon only is irradiated to 1 minute surface of mirror polygon increases, ratio under the state of being cut apart by 2 adjacent minute surfaces when illuminated reduces, its result, the Energy distribution of second light beam spot is that the zone at the two ends of energy increase and decrease shortens, second light beam spot is all is shorter in length than all length of first light beam spot, and the zone that becomes the average central portion of energy is the Energy distribution of long high shape for hat (describing in detail at Figure 11).In addition, so-called herein " Energy distribution of high shape for hat " energy of central portion that is meant light beam spot is on a rough average, and the Energy distribution that the region energy at the light beam spot two ends can change.

Make the Energy distribution of second light beam spot such as the heat of going into that above-mentioned variation can increase time per unit, concentrate the top layer of heated substrates, form high-temperature area in the substrate top layer.Its result, formation is in the stress gradient (second stress gradient) of depth direction inverse change with the stress gradient (first stress gradient) that changes in depth direction that laser scribing adds man-hour.That is, there is compression stress to take place in substrate surface, its reaction force is in the inner tensile stress that forms of substrate.Though have the front end of the slight crack of the line of forming to exist, because concentrating, tensile stress acts on this slight crack front end, so the more deep infiltration of slight crack front end arrives behind the substrate back by complete disjunction in substrate is inner.

Utilize the present invention, do not form full tangent line, and " going ahead of the rest " phenomenon is taken place, can enlarge and practicablely form line (slight crack of finite depth) in substrate with the laser scribing step, carry out laser cutting again and handle with complete disjunction substrate or form the process range of the processing of darker line, realize stable processing.

Can stabilize the end face disjunction processing best in quality of processing end face again.In addition, utilize the present invention, utilize mirror polygon to form light beam spot, can utilize mirror polygon to adjust the Energy distribution of light beam spot when carrying out laser cutting at this light beam spot of scanning.Utilize this can stabilize laser cutting.

(solving the means and the effect of other problems)

In the foregoing invention, the laser light beam diameter of mirror polygon is injected in the position of the converging optical element on the variable light path of being located at the laser beam between LASER Light Source and the mirror polygon with adjustment.

At this, converging optical element can use collector lens (for example crescent lens), condenser.

Whereby, only just can adjust the laser beam footpath in the parallel mobile converging optical element of optical path direction, simple realization makes energy be distributed as the adjustment of long high shape for hat of zone of the average central portion of energy.

In the foregoing invention, make mirror polygon when can be adjusted to the laser cutting step near near the focal position of aforementioned converging optical element.

Whereby, since just more little near near the laser light beam diameter focal position more, so can make mirror polygon near desirable high shape for hat.

In the foregoing invention, can adjust the position of converging optical element and the distance between mirror polygon and the substrate simultaneously.

Whereby, can make energy be distributed as the high shape for hat and the also beam shapes such as length than length direction of adjustable whole light beam spot, so the going into heat and go into thermal region and all can adjust of time per unit, the more process range cut off of expansion of laser light.

Description of drawings

Fig. 1 is the summary pie graph of the base plate processing device that is used when implementing base plate processing method of the present invention of an example.

Fig. 2 is the control system calcspar of the base plate processing device of demonstration Fig. 1.

Fig. 3 is for showing the action illustration of light-path adjusting mechanism 14.

Fig. 4 is the anglec of rotation and the light path of laser beam and the graph of a relation (near illuminated situation the top of a minute surface) of light beam spot of the mirror polygon of display light beam diameter when big.

Fig. 5 is the light path of the anglec of rotation of the mirror polygon of display light beam diameter when big and laser beam and the graph of a relation of light beam spot (situations of illuminated central authorities in a minute surface).

Fig. 6 is the anglec of rotation and the light path of laser beam and the graph of a relation (near illuminated situation the terminal of a minute surface) of light beam spot of the mirror polygon of display light beam diameter when big.

Fig. 7 is display light beam diameter when less, the section shape that is irradiated to the laser beam of the minute surface of rotation at a high speed over time with the graph of a relation of the Energy distribution of the light beam spot that is exposed to glass substrate G by minute surface.

Fig. 8 is the anglec of rotation and the light path of laser beam and the graph of a relation (near illuminated situation the top of a minute surface) of light beam spot of the mirror polygon of display light beam diameter when less.

Fig. 9 is the light path of the anglec of rotation of the mirror polygon of display light beam diameter when less and laser beam and the graph of a relation of light beam spot (situations of illuminated central authorities in a minute surface).

Figure 10 is the anglec of rotation and the light path of laser beam and the graph of a relation (near illuminated situation the terminal of a minute surface) of light beam spot of the mirror polygon of display light beam diameter when less.

Figure 11 is display light beam diameter when less, the section shape that is irradiated to the laser beam of the minute surface of rotation at a high speed over time with the graph of a relation of the Energy distribution of the light beam spot that is exposed to glass substrate G by minute surface.

Figure 12 is the profile of the stress gradient that desire forms when being shown in the laser cutting step in a schematic way.

Figure 13 is the flow chart according to the processing sequence of base plate processing method of the present invention.

Figure 14 is the profile that shows the mechanism of the slight crack that forms finite depth in a schematic way.

Figure 15 is stereogram and the plane that shows the mechanism that forms full tangent line in a schematic way.

Figure 16 is presented at the phenomenon figure in advance that edge of substrate produces.

2: sliding platform 7: pedestal

12: rotation platform 13: laser aid

16: cooling jet 17: elevating mechanism

18: break bar 31: crescent lens

32: speculum 33: mirror polygon

G: glass substrate (brittle substrate) Cr: slight crack

Tr: initial stage be full of cracks

The specific embodiment

(device constitutes)

Below, based on drawing example of the present invention is described.

The base plate processing device that uses when one example is implemented processing method of the present invention at first is described.Fig. 1 is the summary pie graph of the laser break-up device LC1 of an example of the present invention.Fig. 2 is the formation calcspar of the control system of the laser break-up device LC1 of demonstration Fig. 1.

All formations of laser break-up device LC1 at first are described based on Fig. 1.

Pair of guide rails 3,4 on the pallet 1 along configured in parallel in level is provided with the sliding platform 2 that the paper fore-and-aft direction (to call the Y direction in the following text) in Fig. 1 moves back and forth.Between two guide rails 3,4, dispose driving screw 5, screw togather the pillar 6 that is fixed in aforementioned sliding platform 2, sliding platform 2 is moved back and forth along guide rail 3,4 in the Y direction with motor (diagram outer) rotating driving screw 5 in this driving screw 5 along fore-and-aft direction.

Dispose the horizontal pedestal 7 that the left and right directions (to call directions X in the following text) in Fig. 1 moves back and forth at sliding platform 2 upper edge guide rails 8.Connect the driving screw 10a that screws togather by motor 9 rotations at the pillar 10 that is fixed in pedestal 7, driving screw 10a rotating meeting makes slip pedestal 7 move back and forth in directions X along guide rail 8.

Be provided with the rotation platform 12 with rotating mechanism 11 rotations on pedestal 7, with horizontal state the brittle substrate that cuts off object being installed in this rotation platform 12 is glass substrate G.Rotating mechanism 11 makes rotation platform 12 around vertical axle rotation, and is rotatable for being any anglec of rotation to the reference position.Glass substrate G is for example to attract chuck to be fixed in rotation platform 12.

Above rotation platform 12, there are laser oscillator 13 and light-path adjusting mechanism 14 kept by installing rack 15.Light-path adjusting mechanism 14 is by the motor group 14b (motor 34-36) of the position of adjusting light path adjustment element group 14a (crescent lens 31, speculum 32, mirror polygon 33), mobile light path adjustment element group 14a from the laser optical path of laser oscillator 13 ejaculations, links arm group 14c (arm 37-39) formation that light path is adjusted element group 14a and motor group 14b.Crescent lens 31 are to see through the position that arm 37 is connected in lift motor 34 and above-below direction can adjust.Again, speculum 32 is to see through the position that arm 38 is connected in lift motor 35 and above-below direction can adjust.Again, mirror polygon 33 is to see through the position that arm 39 is connected in lift motor 36 and above-below direction can adjust.

The laser beam that is penetrated by laser oscillator 13 forms the light beam with section shape of being desired by above-mentioned light path adjustment element group 14a, is irradiated on the substrate G with light beam spot.At this example is to penetrate circular laser beam, adjusts beam diameter with crescent lens 31, with mirror polygon scanning, forms the laser point LS (Fig. 2) of elliptical shape in fact on substrate G.And, to adjust the 1st light beam spot that uses when light path adjustment element group 14a switches the 1st laser irradiation (laser scribing step), the 2nd light beam spot that the 2nd laser uses when shining (laser cutting step).

In addition, when adjusting,, adjust the operation meeting and complicate though independence is adjusted speculum 32, mirror polygon 33 is fine-tuning.Therefore, but one mobile mirror 32, mirror polygon 33 so that adjust operation and simplify.Particularly, speculum 32, mirror polygon 33 interlocks are moved with the distance of carrying out between substrate G and the mirror polygon 33 adjust, move crescent lens 31 and adjust with the distance of mirror polygon 33 to carry out crescent lens 31.

Be provided with cooling jet 16 at installing rack 15 near light-path adjusting mechanism 14.16 couples of glass substrate G of cooling jet spray cooling medium such as cooling water, helium, carbon dioxide thus.The cooling medium are blowed near the laser point LS of the elliptical shape that is irradiated to glass substrate G, form a cooling point CS (Fig. 2) on the surface of glass substrate G.

Through moving up and down governor motion 17 break bar 18 is installed at installing rack 15.This break bar 18 is to be material with sintering diamond or superhard alloy, possesses with the summit crest line portion of the V font that is the sword leading edge in outer peripheral face, and can be by moving up and down the crimp force of governor motion 17 fine settings to glass substrate G.Break bar 18 is to be exclusively used in when the ora terminalis formation initial stage be full of cracks TR (Fig. 2) of glass substrate G in directions X traveling platform 7 and temporary transient decline.

Again, a pair of

video camera

20,21 is arranged, can mirror the location mark that is engraved on substrate G in the upper fixed of installing rack 15.

Secondly, based on Fig. 2 control system is described.Laser break-up device LC1 possesses the control part 50 of carrying out various processing with the control parameter that is recorded in memory and program (software) and CPU.This control part 50 is that sliding platform 2 is carried out in the control driving, pedestal 7, the table drive part 51 of the location of rotation platform 12 or mobile motor (motor 9 etc.), carry out (the LASER Light Source drive division 52a that comprises driving laser oscillator 13 of Laser Driven portion 52 of laser irradiation, the light-path adjusting mechanism drive division 52b of the motor group 14b that driving light path adjustment element group 14a uses), drive the nozzle drive division 53 of the open and close valve (not illustrating) of controlling the coolant injection that carries out with cooling jet 16, with break bar 18 and move up and down the cutter drive division 54 that governor motion 17 chapped in the glass substrate G formation initial stage, with video camera 20,21 mirror each drive system that the video camera drive division 55 of mark is used in the location that is imprinted at substrate G.Again, control part 50 is connected with the input part 56 that is made of keyboard, slide-mouse etc., the display part 57 that carries out various demonstrations in display frame, and necessary information can be shown in display frame and necessary indication or setting can import.

Again, control part 50 possesses sum total and drives table drive part 51, Laser Driven portion 52 (LASER Light Source drive division 52a, light-path adjusting mechanism drive division 52b), nozzle drive division 53, the cutter drive division 54 machining control portion 58 with the processing of carrying out glass substrate G, carries out Laser Processing according to the order of the 1st laser irradiation, cooling, the 2nd laser irradiation with this machining control portion 58.

Particularly, machining control portion 58 is control cutter drive division 54 and table drive part 51 moving substrate G under the state of falling break bar 18 earlier, carries out the processing of formation initial stage be full of cracks TR whereby.Control table drive part 51, Laser Driven portion 52, nozzle drive division 53 afterwards at irradiating laser light beam (the 1st light beam spot) and spray moving substrate G under the state of refrigerant.Carry out irradiation of the 1st laser and cooling whereby, be carried out at the processing that substrate forms the line that the slight crack by finite depth constitutes.Control the moving substrate G under the state of irradiating laser light beam (the 2nd light beam spot) of table drive part 51, Laser Driven portion 52 afterwards.Carry out the irradiation of the 2nd laser whereby, make the processing processing of complete disjunction (or make) of slight crack infiltration.

(light path adjustment action)

Below explanation is controlled the light path adjustment that light-path adjusting mechanisms 14 (light path is adjusted element group 14a, motor group 14b, arm group 14c) carry out with machining control portion 58.

Fig. 3 particularly, is that explanation changes the beam diameter that exposes to mirror polygon 33 with moving up and down of crescent lens 31 for showing the action illustration of light-path adjusting mechanism 14, makes the action diagram of the Energy distribution variation of the light beam spot that is irradiated to substrate G.

The direct of travel of the laser beam LB0 of the circular section that penetrates from LASER Light Source 13 is towards vertical below, and laser beam LB0 injects crescent lens 31.Laser beam LB1 by crescent lens 31 is by optically focused and continue at vertical direction and advance, and injects speculum 32.This moment, the setting angle of speculum 32 was to be adjusted in the reflecting surface of speculum 32 to inject with 45 degree incident angles and penetrate with the reflection angles of 45 degree, advanced in horizontal direction with the laser beam LB2 of mirror reflects.

The laser beam LB2 that advances in the horizontal direction injects the mirror polygon 33 in the rotation.At this moment, being irradiated to the beam diameter of the minute surface of mirror polygon 33 can be with the variable in distance between crescent lens 31 and the mirror polygon 33.

Fig. 4-Fig. 6 is the anglec of rotation and the light path of laser beam and the graph of a relation of light beam spot of the beam diameter that shows the minute surface be irradiated to mirror polygon 33 mirror polygon when big.

The beam diameter of this state be in crescent lens 31 near speculums 32, the focus that is adjusted into crescent lens 31 is implemented during more near substrate G side than the minute surface of mirror polygon 33.And the beam diameter of this state is to be used when the laser scribing step.

In Fig. 4 (a), note 2 minute surface M0, M1 of the mirror polygon 33 in the clockwise direction rotation.Minute surface M0 is the extremely preceding minute surface that laser beam LB2 irradiation is all arranged in a flash.Carry out in rotation, arrive the time point that laser beam LB2 closes to an end to the irradiation of minute surface M0 after, laser beam LB2 is irradiated to the terminal of minute surface M0 and the top of a time minute surface M1 simultaneously after cutting apart.Fig. 4 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M0.Again, Fig. 4 (d) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.

The energy that is irradiated to the laser beam of minute surface M0, M1 is assigned with the area ratio of the section of divided laser beam.At this moment, the laser beam LB3a that is reflected in minute surface M0 side is the left end portion of position of the light beam spot LS1 of irradiation glass substrate G, and this part is energized.In addition, the laser beam LB3b that is reflected in minute surface M1 side is the right end portion of position of the light beam spot LS1 of irradiation glass substrate G, and this part is energized.

Fig. 4 (b) is the Energy distribution of position of the light beam spot LS1 that is irradiated to substrate G.That is, owing to be split into behind laser beam LB3a, the LB3b illuminatedly, also being divided into 2 parts so bestow the energy of substrate G, the two ends of light beam spot LS1 are heated with the energy that corresponds respectively to the ration of division.

Fig. 5 (a) proceeds for rotation, and laser beam LB2 is irradiated to the state of the middle body of minute surface M1.At this moment, the laser beam LB2 of circular section only is irradiated to 1 minute surface M1.Fig. 5 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.The light beam of the circular section that laser beam LB2 has is directly illuminated.At this moment, the laser beam LB3c that is reflected at minute surface M1 is the central authorities of the position of illumination beam point LS1, gives whole energy to this part.

Fig. 5 (b) is the Energy distribution of position of the light beam spot LS1 that is irradiated to substrate G.Energy is bestowed the middle body of the position of light beam spot LS1, concentrates this part of heating.

Fig. 6 proceeds for rotation again, and laser beam LB2 is irradiated to the terminal of minute surface M1 and the state at the top of a time minute surface M2 simultaneously after cutting apart.Fig. 6 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.Again, Fig. 6 (d) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M2.

The energy of laser beam that is irradiated to minute surface M1, M2 during with Fig. 4 equally the area ratio with the section of divided laser beam be assigned with.At this moment, the laser beam LB3d that is reflected in minute surface M1 side is the left end portion of position of the light beam spot LS1 of irradiation glass substrate G, and this part is energized.The laser beam LB3e that is reflected in minute surface M2 side is the right end portion of the position of illumination beam point LS1, and this part is energized.

Fig. 6 (b) is the Energy distribution of position of the light beam spot LS1 that is irradiated to substrate G.The energy that is irradiated to substrate G is divided into 2 parts, and the two ends of light beam spot LS1 are heated with the energy that corresponds respectively to the ration of division.

Afterwards, repeat the laser irradiation of Fig. 4 to Fig. 6, form the light beam spot LS1 of Energy distribution with the Energy distribution stack that shows with Fig. 4 (b), Fig. 5 (b), Fig. 6 (b) with the mirror polygon 33 of at a high speed rotation.

Fig. 7 for show be irradiated to the laser beam LB2 of the minute surface M1 of rotation at a high speed section shape over time with the graph of a relation of the Energy distribution of the light beam spot LS1 that is exposed to glass substrate G by minute surface M1.

Shown in Fig. 7 (a), the section shape that is irradiated to the laser beam LB2 of minute surface M1 carries out with rotation and changes.

That is during the range of exposures of the top of minute surface M1 (with the boundary of minute surface M0) by laser beam LB2, the section shape that is irradiated to the laser beam LB2 of minute surface M1 is the shape of a shortage of circular section, and sectional area increases gradually during this period.Afterwards, the section shape that is irradiated to the laser beam LB2 of minute surface M1 becomes circle, enter the range of exposures of laser beam LB2 to the terminal (with the boundary of minute surface M2) of minute surface M1 till circular section all lasting.Afterwards, during the terminal of the minute surface M1 range of exposures by laser beam LB2, the section shape that is irradiated to the laser beam LB2 of minute surface M1 becomes the section shape of a shortage of circular section once again, and sectional area reduces gradually.

The Energy distribution that is formed at the light beam spot LS1 on the substrate G with minute surface M1 can change corresponding to the variation of this sectional area.Show Energy distribution at Fig. 7 (b).The Energy distribution of light beam spot LS1 is that the energy of central portion is average (high shape for hat), the gentle Energy distribution that changes in its two ends.The width of the gentle part at two ends is to be equivalent to during the top of minute surface M1 or terminal are by the range of exposures of laser beam LB2 to be irradiated to scope on the substrate G by minute surface M1 laser light reflected light beam.Therefore, the width of the gentle part that changes of the Energy distribution at the two ends of light beam spot LS1 can become with the beam diameter of laser beam LB2 and become big greatly.Afterwards with repeat the to have Fig. 7 irradiation of Energy distribution of (b) of each minute surface of mirror polygon 33 of rotation.

Secondly explanation is irradiated to the less situation of beam diameter of minute surface.Fig. 8-Figure 10 is the anglec of rotation and the light path of laser beam and the graph of a relation of light beam spot of the beam diameter that shows the laser beam LB2 be irradiated to minute surface mirror polygon hour.

The beam diameter of this state is in the position of adjusting crescent lens 31 so that the focus of crescent lens 31 is implemented when coming near the minute surface M1 of mirror polygon 33.And the beam diameter of this state is to be used when the laser cutting step.

In Fig. 8 (a), note 2 minute surface M0, M1 of the mirror polygon 33 in the clockwise direction rotation equally with Fig. 4 (a).Minute surface M0 is the extremely preceding minute surface that laser beam LB2 irradiation is all arranged in a flash.Carry out in rotation, arrive the time point that laser beam LB2 closes to an end to the irradiation of minute surface M0 after, laser beam LB2 is irradiated to the terminal of minute surface M0 and the top of a time minute surface M1 simultaneously after cutting apart.Fig. 8 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M0.Again, Fig. 8 (d) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.Because beam diameter is less, so 2 minute surface M0, M1 irradiated scopes of while (from top, terminal to the scope of beam diameter) are littler than the situation of Fig. 4.

Energy and Fig. 4 of being irradiated to the laser beam of minute surface M0, M1 are assigned with the area ratio of the section of divided laser beam equally.At this moment, the laser beam LB3a that is reflected in minute surface M0 side is the left end portion of position of the light beam spot LS1 of irradiation glass substrate G, and this part is energized.In addition, the laser beam LB3b that is reflected in minute surface M1 side is the right end portion of the position of illumination beam point LS1, and this part is energized.

Fig. 8 (b) is the Energy distribution of position of the light beam spot LS1 that is irradiated to substrate G.That is, owing to be split into behind laser beam LB3a, the LB3b illuminatedly, also being divided into 2 parts so be irradiated to the energy of substrate G, the two ends of light beam spot LS1 are heated with the energy that corresponds respectively to the ration of division.

Fig. 9 (a) proceeds for rotation, and laser beam LB2 is irradiated to the state of the middle body of minute surface M1.At this moment, the laser beam LB2 of circular section only is irradiated to 1 minute surface M1.Fig. 9 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.The light beam of the circular section that laser beam LB2 has is directly illuminated.At this moment, the laser beam LB3c that is reflected at minute surface M1 is the central authorities of the position of illumination beam point LS1, gives whole energy to this part.

Fig. 9 (b) is irradiated to the Energy distribution of position of the light beam spot LS1 of substrate G for this moment.Energy is bestowed the middle body of the position of light beam spot LS1, concentrates this part of heating.

Figure 10 proceeds for rotation again, and laser beam LB2 is irradiated to the terminal of minute surface M1 and the state at the top of a time minute surface M2 simultaneously after cutting apart.Figure 10 (c) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M1.Again, Figure 10 (d) is for showing the profile of the laser beam LB2 that is irradiated to minute surface M2.

Energy and Fig. 6 of being irradiated to the laser beam of minute surface M1, M2 are assigned with the area ratio of the section of divided laser beam equally.At this moment, the laser beam LB3d that is reflected in minute surface M1 side is the left end portion of position of the light beam spot LS1 of irradiation glass substrate G, and this part is energized.The laser beam LB3e that is reflected in minute surface M2 side is the right end portion of the position of illumination beam point LS1, and this part is energized.

Figure 10 (b) is irradiated to the Energy distribution of position of the light beam spot LS1 of substrate G for this moment.The energy that is irradiated to substrate G is divided into 2 parts, and the two ends of light beam spot LS1 are heated with the energy that corresponds respectively to the ration of division.

Afterwards, repeat the laser irradiation of Fig. 8 to Figure 10, form the light beam spot LS1 of Energy distribution with the Energy distribution stack that shows with Fig. 8 (b), Fig. 9 (b), Figure 10 (b) with the mirror polygon 33 of at a high speed rotation.

Figure 11 for show be irradiated to the laser beam LB2 of the minute surface M1 of rotation at a high speed section shape over time with the graph of a relation of the Energy distribution of the light beam spot LS1 that is exposed to glass substrate G by minute surface M1.

Owing to the beam diameter of the laser beam LB2 that is irradiated to minute surface M1 is little, so shown in Figure 11 (a), irradiated sectional area diminishes than the bigger all property of situation of beam diameter that show with Fig. 7 (a), but energy density improves.In addition, shown in Figure 11 (a), the section that is irradiated to the laser beam LB2 of minute surface M1 carries out with rotation and changes.That is, with Fig. 7 (a) equally in during the range of exposures of the top of minute surface M1 (with the boundary of minute surface M0) by laser beam LB2 and the range of exposures of the terminal (with the boundary of minute surface M2) of minute surface M1 by laser beam LB2 during be irradiated to the laser beam LB2 of minute surface M1 section shape be the section shape of a shortage of circular section, increase or minimizing in that this scope interior profile is long-pending.The range of exposures of laser beam LB2 therebetween all be irradiated to minute surface M1 during be irradiated to the laser beam LB2 of minute surface M1 section shape become circular section.

Because the beam diameter of laser beam LB2 is little, so near the top of minute surface M1 and to be irradiated to the size of scope of sectional area variation of laser beam LB2 of minute surface M1 near the terminal littler than Fig. 7 (a), sectional area acutely increases and decreases.The Energy distribution that is formed at the light beam spot LS1 on the substrate G with minute surface M1 can change corresponding to the variation of this sectional area.The Energy distribution that shows the light beam spot LS1 of this moment in Figure 11 (b).In addition, for ease of relatively, represent beam diameter Energy distribution hour, the Energy distribution (Energy distribution of Fig. 7 (b)) when representing that with some chain lines beam diameter is big with solid line.

The beam diameter of irradiated laser beam LB2 is more little, and the Energy distribution of light beam spot LS1 is that the zone at two ends of energy variation is short more, and all length of light beam spot LS1 shortens, and the zone that becomes the average central portion of energy is the Energy distribution of long high shape for hat.

Afterwards by each minute surface of the mirror polygon 33 of rotation to have the light beam spot LS1 reirradiation with the same Energy distribution of minute surface M1.

As above-mentioned, the height of only adjusting crescent lens 31 can carry out the adjustment of the Energy distribution of light beam spot.

In addition, though change the Energy distribution that the height of renewing moon-shaped lens 31 can be adjusted the light beam spot that is irradiated to substrate G, all length of light beam spot this moment also can change.

Therefore, do not wishing to make the long axis length of light beam spot when each step changes, otherwise or wish that in the laser cutting step length adjustment with major axis is for more in short-term, move mirror polygon 33, speculum 32 with the distance while one of crescent lens 31 of adjustment and mirror polygon 33, the distance of adjustment and substrate G is also adjusted long axis length.

Whereby, heat with light beam spot shape of being desired and the Energy distribution of being desired.

When the laser cutting step, the light beam spot of the Energy distribution of long high shape for hat gives the bigger heat of going into the short time by zone that irradiation has an average central portion of energy.

Figure 12 is for showing the profile of the stress gradient that forms with processing method of the present invention desire when the laser cutting step in a schematic way.Making light beam spot is the Energy distribution of high shape for hat, concentrates heating from the substrate top layer in the short time, forms heating region H.Afterwards, form big compression stress HR, influenced by it and have opposite tensile stress CR to take place in substrate inside in the substrate top layer.If there is the slight crack Cr that produces with not long ago laser scribing step exist in substrate inside, tensile stress can concentrate on the front end of slight crack Cr, its result, the more deep infiltration of slight crack Cr.Again, slight crack Cr arrives the back side and can make complete disjunction.

(processing sequence)

Processing sequence when below processing unit (plant) LC1 disjunction substrate G is used in explanation.Figure 13 is the flow chart of processing sequence.

At first, substrate G mounting on rotation platform 12, is fixed to attract chuck.Rotation platform 12 is moved under the

video camera

20,21, detect the alignment mark (not illustrating) that is imprinted at glass substrate A with video camera 20,21.Concern based on the position of its testing result record line preset lines with rotation platform 12, sliding platform 2, pedestal 7.Start rotation platform 12 and sliding platform 2 make the sword leading edge direction of break bar 18 arranged side by side with the direction of line preset lines afterwards, make the sword leading edge come neighbouring (S101) of the position of formation initial stage be full of cracks.With the position of this moment as processing starting position record.

Afterwards, start elevating mechanism 17 is to fall break bar 18.

Mobile rotation platform 12 (pedestal 7) is with crimping edge of substrate break bar 18.Formation initial stage be full of cracks TR whereby.Start elevating mechanism 17 is with rising break bar 18 (S102) behind the formation initial stage be full of cracks TR.

Afterwards, substrate is returned the processing starting position, the primary laser beam of start laser aid 13 irradiations.Adjust the position of crescent lens 31 this moment, in the minute surface of mirror polygon 33 with bigger beam diameter (with reference to figure 4-Fig. 7) incident.Make the Energy distribution of the Energy distribution of the light beam spot that is formed at substrate G whereby for the gentle state that rises.Again, from cooling jet 16 injected cool coals.Mobile rotation platform 12 (pedestal 7) under this state is by forming line (S103) along line preset lines scanning light beam point and cooling point.

Afterwards, substrate G is returned the processing starting position, shine secondary laser beam.Away from speculum 32, dwindle the beam diameter (with reference to figure 8-Figure 11) of the minute surface of injecting mirror polygon 33 when make crescent lens 31 than primary irradiation this moment.Whereby, be formed at the rapid rising of Energy distribution of the light beam spot of substrate G, be Energy distribution than the higher shape for hat first time.Though cooling jet 16 can continue to spray, since also inessential, so stop at this.Mobile rotation platform 12 (pedestal 7) under this state, the light beam spot that has the Energy distribution of high shape for hat along the line scanning that forms with last time scanning.Whereby, the slight crack that has formed line deeply permeates, quilt disjunction (S104) fully behind the arrival substrate back.

What form in this way is scribed ss very good processing section, and end face intensity is grow also.

The present invention can be used in brittle substrates such as glass substrate are formed dark line or the processing of disjunction fully.

Claims

1. the processing method of a brittle substrate, the laser beam that penetrates from LASER Light Source with the mirror polygon repeated reflection of at a high speed rotation is to form light beam spot in brittle substrate, relatively move aforementioned light beam spot with the processing aforesaid base plate along the line preset lines of setting in aforesaid base plate, it is characterized in that:

This processing method is made of following step:

Make first light beam spot that laser irradiation for the first time produces along the line preset lines heated substrates that relatively moves, and cool off position after first light beam spot passes through immediately, result from stress gradient that depth direction changes laser scribing step according to this with the line that forms finite depth; And

Second light beam spot that laser irradiation is for the second time produced relatively moves along aforementioned line, so that the laser cutting step of more deep infiltration of aforementioned line or complete disjunction;

When cutting off step, aforementioned laser injects the laser light beam diameter of mirror polygon, the laggard row irradiation of the laser light beam diameter of injecting when being adjusted into less than the laser scribing step.

2. according to the processing method of the brittle substrate of claim 1, it is characterized in that the position of the converging optical element on the light path of the laser beam between LASER Light Source and the mirror polygon is located in change, inject the laser light beam diameter of mirror polygon with adjustment.

3. according to the processing method of the brittle substrate of claim 2, it is characterized in that, when the laser cutting step, mirror polygon is adjusted near the focal position that approaches to aforementioned converging optical element.

4. according to the processing method of the brittle substrate of claim 2 or 3, it is characterized in that, adjust the position of converging optical element and the distance between mirror polygon and the substrate simultaneously.