JP4839663B2 - Laser processing method and laser processing apparatus - Google Patents

Description

  The present invention relates to a laser processing method and a laser processing apparatus for processing a workpiece by irradiating pulsed laser light.

In manufacturing a member such as a thin film composed of a conductor such as an insulator, a semiconductor, or a metal, processing such as removal or shaping other than a predetermined portion is performed in order to make the shape and properties desired. Yes.
As a technique used for such processing, for example, wet etching with an etching solution such as an acid or dry etching with an etching gas can be cited.
Wet etching is one method established historically, and dry etching is widely used as a method suitable for fine patterning.

However, since the wet etching needs to go through steps such as resist coating, patterning exposure, selective removal using an etching solution, cleaning, and drying, the procedure is complicated. Moreover, it has been pointed out as a problem that immersion in an etching solution may not be appropriate depending on the shape and type of a sample to be removed, that is, a workpiece, and that fine patterning is difficult.
Although dry etching can achieve fine patterning, the basic process is the same as in wet etching, the procedure is complicated, and the etching apparatus is more expensive than in wet etching, Furthermore, it is necessary to consider the control of the atmospheric gas, which takes time.

On the other hand, there has been proposed a technique for removing and shaping a member to be processed by irradiating a pulse laser beam (see, for example, Patent Document 1).
However, when the pulse width of the laser beam is, for example, on the order of nanoseconds (ns), the surrounding material that is not directly irradiated with the laser beam is melted by the thermal melting of the material constituting the member and the accompanying thermal diffusion. Further, there is a problem that the material is deformed and the molten material is scattered and reattached to the surroundings.
Therefore, the pulse width in the pulse laser beam irradiation is selected to be shorter, and for example, the selection of the workpiece is performed by irradiating the pulse laser beam with a short pulse width of less than 10 picoseconds (ps) such as femtosecond (fs) order. Proposals have been made for processing methods that perform automatic removal and shaping.

  According to such a method of irradiating a short pulse width laser beam, unlike the case of irradiating a pulse laser beam having a pulse width of 10 picoseconds or more, such as the nanosecond order described above, the heat is diffused to the surroundings. Since it is possible to irradiate pulsed light with a short period, the so-called multiphoton absorption process that does not cause thermal diffusion causes the material constituting the member to evaporate or vaporize directly without going through the melting process, and sharpness or selectivity. High removal can be performed.

  However, in the case of processing by such a short pulse width laser beam, the member material scattered in the atmosphere in the state of molecules or ions collides with gas molecules constituting the atmosphere, or bonds with the gas molecules, Or, by being rapidly cooled, it becomes dust (dust, removed debris) and reattaches on the workpiece.

  For example, as shown in FIG. 8A, a predetermined groove can be formed in the irradiated portion 102 by processing the member 101 to be processed by a Cr (chromium) thin film on the substrate with a short pulse width laser beam. However, as shown in FIG. 8B, an enlarged view of a portion indicated by d in the drawing shows that the dust 105 accumulates and adheres to the periphery of the processed groove 104 formed by light irradiation, for example, the irradiated side edge 103. That is, there is no melting mark, and a large number of submicron-order dusts 105 are adhered to the surface of the member so as to be folded.

Such dust is not attached in a molten state as in the case of processing with a laser beam having a pulse width of the order of nanoseconds as described above, but attractive force generated on the substrate surface, such as van der Waals force or electrostatic force 9B, for example, by wiping with a cotton swab soaked in isopropyl alcohol (IPA) or washing away by ultrasonic cleaning, as shown in FIGS. 9A and 10A. And as shown to FIG. 10B, it can remove again and the member surface can be wash | cleaned.
JP 09-190995 A

  However, when cleaning is performed using a contact material such as a cotton swab, new dust may be generated from the contact material used for removal, or the member surface may be damaged by the contact material. In addition, a cleaning technique using a liquid such as ultrasonic cleaning may not always be appropriate depending on the application of the member, that is, the type and state of the member, circumstances in the manufacturing process, and the like.

  In addition, for example, it is possible to reduce the reattachment of dust itself by reducing the pressure in the vicinity of the irradiated part, that is, by increasing the mean free path of the vaporized member material, but it is effective. The method requires a high degree of vacuum, and it is assumed that processing is performed in a dedicated chamber similar to the dry etching described above, which increases the cost of the device configuration and sufficiently reduces dust. It cannot always be suppressed.

  The present invention has been made in view of the above-described problems, and its purpose is a non-contact type, which does not necessarily require a high degree of vacuum, and can process and clean the surface of a member by a dry process. Another object of the present invention is to provide a laser processing method and a laser processing apparatus.

The laser processing method according to the present invention includes a first pulse laser beam that has a pulse width of less than 10 picoseconds and causes a workpiece to evaporate, and a pulse width that is less than 10 picoseconds and sandwiches the first pulse laser beam. And a second pulsed laser beam that is formed so that the irradiated region does not overlap the irradiated region of the first pulsed laser beam and deforms the irradiated portion by expansion. Are formed by dividing a common laser beam, and the first pulse laser beam and the second pulse laser beam are irradiated in parallel.
By irradiating the first pulse laser beam, the member material constituting the irradiated portion of the member to be processed is evaporated, and for example, the second pulse laser beam irradiation is performed on the main adhered portion of the dust reattached to the member surface. This facilitates the deformation and expansion of the member material that constitutes the adhering portion.

A laser processing apparatus according to the present invention includes a light source that emits a pulse laser beam of less than 10 picoseconds, a beam separation molding element that separates the laser beam from the light source into a plurality of laser beams, and a plurality of separated laser beams. And an objective lens that focuses light on the workpiece. The beam separation shaping element separates the first pulsed laser beam for evaporating the material of the workpiece and the first pulsed laser beam back and forth with respect to the scanning direction , and the irradiation region thereof is the first pulsed laser beam . The second pulse laser beam is formed so as not to overlap the irradiation region of the first pulse laser beam, and deforms the irradiated portion by expansion.
With this configuration, in the apparatus of the present invention, it is possible to select not only a spatial correlation but also a temporal correlation when irradiating the first and second pulse laser beams.

  According to the laser processing method of the present invention, the first and second pulse laser beams, which are so-called short pulse width laser beams having a pulse width of less than 10 picoseconds, can be vaporized in the workpiece. Since the member to be processed is irradiated with the laser energy and the second laser energy that enables deformation of the member to be processed, for example, the second pulse laser is applied to the main attachment portion of the dust reattached to the member surface. By irradiating with light, dust on the adhering part can be floated or scattered by deformation or expansion of the member material constituting the adhering part, and the member to be processed which has been removed or shaped by the first pulse laser light irradiation The surface of the can be cleaned.

  The laser processing apparatus according to the present invention has a configuration capable of simultaneously irradiating a workpiece with first and second pulse laser beams, which are so-called short pulse width laser beams having a pulse width of less than 10 picoseconds. Therefore, it is possible to irradiate the first and second pulsed laser beams by selecting not only the spatial correlation but also the temporal correlation. Desired removal or shaping of the processed member and desired cleaning of the surface of the processed member with the second pulse laser beam can be performed in accordance with the state of dust.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment of Laser Processing Apparatus>
First, a first embodiment of a laser processing apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the laser processing apparatus 1 according to the present embodiment includes at least a light source 6 that emits a pulse laser beam having a pulse width of less than 10 picoseconds, a beam separation shaping element 10, and a workpiece 13. And a gas blowing means 14 and a gas suction means 15 for generating an air flow in the vicinity of the in-focus position of the irradiated portion of the workpiece 13.
In the present embodiment, the stage 12 can be moved and adjusted in a two-dimensional direction substantially orthogonal to the optical axis of the pulsed laser beam, whereby the workpiece member 13 can be scanned and irradiated with the pulsed laser beam from the light source 6. It becomes possible.

In the present embodiment, an optical element for guiding the pulse laser beam emitted from the light source 6 to the workpiece 13 between the light source 6 and the beam separation / shaping element 10, for example, the lens 7, the mirror 8, and the like. A focus adjusting optical element 9 is provided, and an objective lens 11 is provided between the beam separating / shaping element 10 and the workpiece 13.
A so-called collimator lens can be used as the lens 7, and the mirror 8 can be a rising or scanning galvanometer mirror. The focus adjusting optical element 9 can be configured by a pair of lenses 9a and 9b.

The pulse laser beam from the light source 6 is split in the beam separation / shaping element 10 as shown in FIG. 2, and the first pulse laser beam L ₁ to be a condensed beam for evaporating the material of the workpiece 13 and the target beam. A second pulsed laser beam L ₂ for cleaning (in this example, side beams L _2a and L _2b ) that deforms the material around the portion to be processed by the first pulsed laser beam of the processing member 13 is formed.

In this embodiment, the second pulse laser beams L _2a and L _2b are formed by the beam separation / shaping element 10 before and after the first pulse laser beam L ₁ with respect to the scanning direction. The shaped beam extends in a direction perpendicular to the direction. Thus, the second pulse lasers L _2a and L _2b are irradiated to a predetermined removal area, that is, a wider area (S _2a and S _2b ) than the irradiated portion S ₁ of the first pulse laser beam L _1. It is possible to deform, for example, expand the irradiated part 13 with dust (not shown) which has been evaporated by the first pulse laser irradiation and then re-adhered to the surroundings by energy lower than that of the first pulse laser beam. It becomes possible to float or scatter.

As a more specific configuration of the beam separation / shaping element 10, for example, as shown in FIG. 3A, a first cylindrical lens 16 a provided in front of the objective lens 11, and between the objective lens 11 and the workpiece 13 are used. The diffraction grating 17 and the second cylindrical lens 16b provided in the configuration can be used.
In this configuration, the laser light L ₀ from the light source 6 (not shown) is shaped by the first cylindrical lens 16 a and is incident on the diffraction grating 17 through the objective lens 11, and the zero-order and ± first-order diffractions. After the light is created, the zero-order light sufficiently separated from the ± first-order light is shaped again by the second cylindrical lens 16b, and the substantially pulse-shaped collection by the first pulse laser light is formed on the irradiated member 13. the light spot S _1, it is possible to form a light condensing spot S _2a and S _2b of elongated by the second pulse laser beam.

Further, as another configuration of the beam separation / shaping element 10, for example, as shown in FIG. 3B, a beam dividing mask 18, a condenser lens 19, and first and first lenses provided only in front of the objective lens 11. Two cylindrical lenses 20a and 20b can be used.
In this configuration, after the laser beam L ₀ from the light source 6 (not shown) is divided into three by the beam dividing mask 18, each laser beam is divided into, for example, the central condenser lens 19 and the first and second lenses. Shaped by the cylindrical lenses 20a and 20, and through the objective lens 11, on the irradiated member 13, a substantially circular condensing spot S1 by the _first pulse laser beam and an elongated by the second pulse laser beam. Shaped condensing spots _S2a and _S2b can be formed.

  For example, the beam separation / shaping element 10 having such a configuration can perform irradiation of the first pulse laser beam and irradiation of the second pulse laser beam in parallel in time or space, or the first pulse laser beam. The light and the second pulse laser light can be formed by a common light source, and the first pulse laser light and the second pulse laser light can be formed by dividing the common laser light. In addition, the workpiece can be reliably cleaned with a simpler and less expensive apparatus configuration.

<Embodiment of Laser Processing Method>
Next, an embodiment of the laser processing method according to the present invention will be described with reference to FIG. 1, taking as an example the case of using the laser processing apparatus described above.

  In this embodiment, first, a pulse laser beam having a pulse width of less than 10 picoseconds is emitted from the light source 6 and introduced into the beam separation / shaping element 10 through the lens 7, the mirror 8, and the focus adjusting optical element 9.

Subsequently, in the beam separation / shaping element 10 having the above-described configuration, the first pulsed laser light L _{1 that} is a condensed beam that divides the laser light and evaporates the material of the workpiece 13 and the first of the workpiece 13. A second pulse laser beam L ₂ for cleaning (in this example, side beams L _2a and L _2b ) for deforming the material around the processed portion by the pulse laser beam is formed.

Due to the beam splitting by the beam separation / shaping element 10, a predetermined removal area of the workpiece 13, that is, a wider area (S _2a and S _2b ) than the irradiated portion S ₁ of the first pulsed laser light L ₁ is used. It is possible to irradiate two pulse lasers L _2a and L _2b , and dust (not shown) reattached after transpiration by the first pulse laser irradiation with lower energy than the first pulse laser light. Can be floated or scattered by deforming, for example, expanding the irradiated portion 13.

Subsequently, the processed portion of the processing member 13 is irradiated with the first and second pulse laser beams formed by the beam separation / shaping element 10 through the objective lens 11.
During this irradiation or before and after irradiation, in the present embodiment, an air flow is generated by the gas blowing means 14 and the gas suction means 15 in the vicinity of the in-focus position of the irradiated portion of the workpiece 13. As a result, the dust (not shown) adhering to the member surface that floats or scatters due to deformation, for example, expansion due to the second pulse laser beam can be efficiently separated from the member surface, and the member surface is cleaned. Is achieved.

In addition, the first and second pulse laser beam irradiations in the present embodiment can be performed as scanning irradiations by adjusting the movement of the stage 12, for example.
That is, as shown in FIG. 4, the first scan is performed by combining the scan with respect to the first directional axis (x-axis in the figure) and the feed or slide with respect to the second directional axis (y-axis in the figure). ₁₁ is performed, and then the re-scan is repeatedly started from the positions S ₁₂ , S ₁₃ ,... To perform the scanning irradiation of the first pulse laser beam two-dimensionally, Dust floating or scattering in a desired range is possible. In the figure, the second pulse laser beam spot is not shown.

  Further, when two-dimensionally scanning and irradiating the pulse laser beam in this way, by irradiation with a short pulse width laser beam having a pulse width of less than 10 picoseconds, preferably a pulse laser beam having a pulse width on the order of femtoseconds, for example, When processing a conductor such as a metal, a semiconductor, and an insulator, for example, if the member material can be removed to a depth of 5 nm by one pulse irradiation, 15 nm and five times by three pulse irradiations. The member material can be removed to a depth of 25 nm by pulse irradiation and 50 nm by 10 pulse irradiations. Therefore, by performing laser beam irradiation by such two or more pulse irradiations, a member can be obtained by a so-called drilling technique. It is desirable to dig up.

In that case, the optimum scanning speed and scanning order can be determined by combining scanning optical system elements such as the scanning speed, the condensing performance of the irradiation beam, and the repetition frequency of the laser pulse with the number of drilling operations for one condensing spot S. It is desirable to select a method.
That is, the beam diameter φ uniquely determined from the focusing performance, that is, Airy Disc Size (1.22 × λ / NA, where λ is the wavelength), and the repetition frequency of the pulses are considered to be adjacent to each other. By determining the scanning speed, it is desirable to perform pulse irradiation with almost no gap for a predetermined removal length.

In addition, it is desirable that the scanning irradiation of the pulsed laser light is performed not only at least partially adjacent to each other but also at least partially overlap each other as necessary.
This is because the transpiration of the member material by the multiphoton absorption process proceeds only within the range of about 0.6r or less with respect to the diameter of the central portion of each focused spot. On the other hand, it is desirable to overlap 20% or more, particularly desirably 30% or more.

In addition, after scanning in advance, when performing scanning again after feeding in the second direction axis, i.e., the y direction, particularly when performing light irradiation partially overlapping with already irradiated portions, It is desirable that the rescan be performed with a lower laser energy or a smaller number of pulses as compared to a scan performed in advance.
This is lower in rescanning because the irradiation range includes a portion that has already been removed by laser light irradiation, and the irradiated portion in the rescan is adjacent to the portion that has already been removed. This is because desired processing such as removal of a target depth can be performed with laser energy or a smaller number of pulses.

  On the other hand, considering the pulse width, the shorter the pulse width, the higher the instantaneous acceleration received by the dust due to deformation of the member, so not only can a high effect be obtained by removing dust attached with stronger electrostatic force, Even with a substrate material having a small coefficient of thermal expansion, a higher removal effect can be obtained. Furthermore, regarding the light collecting performance, the numerical aperture (NA) is increased within a range that does not exceed 1, and the diffraction limit size determined by the NA and wavelength (Airy Disc Size; φ to 1.22 × It is considered that more effective removal can be achieved by setting removal debris (foreign matter) having a size not exceeding (λ / NA, λ is a wavelength) to be removed. This is because the van der Waals force increases in proportion to the mass of the foreign substance and the electrostatic force increases in proportion to the surface area of the foreign substance. This is because it occurs.

Further, it is considered that more effective dust removal can be realized by improving the light collecting performance. This means that laser irradiation with higher focusing performance can increase the density of optical energy that can be concentrated within the diffraction limit of the focused beam, which is equivalent to increasing the concentration of thermal energy. For this reason, heat can be more effectively transferred to a workpiece made of a material having a low coefficient of thermal expansion. Therefore, it is possible to cope with various materials by selecting appropriate energy collection performance or maintaining high NA while selecting the input energy and laser energy in consideration of the thermal expansion coefficient of the material of the workpiece. I think it can be done.
For example, the irradiation of at least the second pulse laser beam is performed by selecting the numerical aperture of the optical system having a numerical aperture of 0.01 or more and less than 1.0, depending on the material of the workpiece, for example, If the workpiece is made of a material with a relatively small coefficient of linear expansion (or coefficient of thermal expansion), the numerical aperture is selected to be 0.95 or more, so that the dust or dust floats or scatters in the dry process. Is possible.

<Second Embodiment of Laser Processing Apparatus>
Next, a second embodiment of the laser processing apparatus according to the present invention will be described with reference to FIG.
As shown in FIG. 5, the laser processing apparatus 1 according to the present embodiment includes at least a light source system 2, an optical system 3, and an irradiation system 4.

  The light source system 2 in the present embodiment includes a main light source 21 by Tsunami (Ti: Sapphire Laser, center wavelength 800 nm, pulse width 100 fs or less, repetition frequency 80 MHz) manufactured by Spectra-Physics, which is an oscillator, and Spectra, which is a regenerative amplifier, for example. Auxiliary light source 22 and amplifier 23 by Spitfire (central wavelength 800 nm, pulse width 100 fs or less, repetition frequency 1 Hz to 1 kHz) manufactured by Physics Co., Ltd., mirror 24 for guiding pulse laser light from the main light source 21 to the amplifier 23, and the main light source 21 And an adjuster 25 for aligning the phase and deflection of the light from the auxiliary light source 22.

  The optical system 3 in this embodiment includes, for example, an ND filter (Neutral Density Filter) 31 that adjusts the amount of pulsed laser light from the light source system 2, and an in-plane alignment adjustment mirror that defines an optical path that leads to the irradiation system 4. 32 and 33 and an afocal optical system 34 for adjusting the optical axis alignment. Further, the afocal optical system 34 in the present embodiment has a configuration in which, for example, a slit 36 by a pinhole is provided between lenses 35 and 37 having a focal length of 250 mm.

The irradiation system 4 in this embodiment transmits a light from the mirror 41 introduced from the optical system 3 and the light from the mirror 41, and detects light from the objective lens side described later, for example, by a CCD (Charge Coupled Device). A beam splitter 47 that reflects on a container (not shown), an objective lens 43 that condenses the light from the mirror 41, and a workpiece 5 that is an object to be irradiated with the condensed pulsed laser light are placed. A stage 44, an illumination light source 45 that illuminates the stage 44, a beam splitter 42 that guides light from the illumination light source 45 to the stage 44, and a beam separation shaping element 48.
The irradiation system 4 is configured as a so-called microscope optical system. The stage 44 is controlled by, for example, a computer (not shown), and can be moved and selected in at least a two-dimensional plane substantially orthogonal to the optical axis of the pulse laser beam.

In this laser processing apparatus 1, the pulse width and irradiation energy of the pulsed laser light introduced from the light source system 2 through the optical system 3 to the irradiation system 4 are made to correspond to the materials constituting the workpiece 5, respectively. By adjusting each other, it is desirable to select a value that allows the member material to evaporate without melting through the multiphoton absorption process in the irradiated portion of the member 5 to be processed.
Note that when the pulse width is 10 picoseconds or more, the number of materials through which the multiphoton absorption process proceeds is extremely small, and thermal melting and thermal diffusion based on the one-photon absorption process proceeds. The width is preferably selected to be less than 10 picoseconds, desirably less than 1 picosecond, and particularly desirably 1 to 500 femtoseconds or less.

Also in this embodiment, although not shown, the beam separation / shaping element 48 can be configured by a cylindrical lens, a diffraction grating, a beam splitting mask, etc., as in the first embodiment, and the irradiated member 5, a substantially circular condensing spot S ₁ by the first pulse laser beam and an elongated condensing spot S _{2 a} and S _{2 b} by the second pulse laser beam can be formed.
That is, also with the laser processing apparatus according to the present embodiment, the irradiation of the first pulse laser beam and the irradiation of the second pulse laser beam can be performed in time or space in parallel, or the first pulse laser beam can be emitted. Laser light and the second pulse laser light can be formed by a common light source, and further, the first pulse laser light and the second pulse laser light can be formed by dividing the common laser light. It is said.

<Example>
An embodiment of the laser processing method according to the present invention will be described with reference to FIGS.
FIG. 6A shows a photograph as an example of the result of removing dust by performing airflow, that is, air blowing and second pulse laser light irradiation, on an Al (aluminum) film having a thickness of 500 nm. In addition, FIG. 6B is a photograph at the stage where only the first pulse laser beam irradiation was performed and only the processing grooves were formed. In FIGS. 6A and 6B, black spots that are seen from the entire surface away from the vicinity of the irradiated portion are fine irregularities of the Al film, and are different from dust (dust) deposited in the vicinity of the irradiated portion.
In the present embodiment, the irradiation conditions of the first and second pulse laser beams are as follows: energy is 1.4 J / cm ² and 0.75 J / cm ² , the NA of the optical system is 0.65, and the repetition frequency is 1 kHz. The scanning speed was 333 μm / s, the scanning width (a in FIG. 4) was 200 μm, the scanning pitch (b in FIG. 4) was 0.5 μm, and the number of scans was 20 times.

FIG. 6A shows that dust (removed debris) adhering to the substrate can be removed almost completely, and the first pulse laser irradiation and the second pulse laser irradiation are performed under the same scanning conditions. Therefore, it was confirmed that the dust could be removed by the second pulse laser beam while removing the thin film, that is, the member material by the first pulse laser beam.
As shown in FIG. 7A, when dust removal is attempted only by airflow, that is, air blow, the dust can be reduced compared to the previous state as shown in FIG. 7B, but sufficient removal is possible. Since it was not made, it was confirmed that the member surface was cleaned by the laser processing method according to the present invention.

As for pulse laser light irradiation in this embodiment, the scan speed is about 235 μm / s or about 313 μm / s, the moving distance in the longitudinal direction (scan direction, X axis) is 100 μm to 200 μm, and the pitch direction (Y axis) The scan interval was 0.50 μm and the number of scans was 20. Therefore, the approximate removal range on the member was 100 μm or 200 μm × 10 μm.

  Although the embodiments of the laser processing method and the laser processing apparatus according to the present invention have been described above, the materials used in the description of the above embodiments and the numerical conditions such as the amount, processing time, and dimensions are preferable examples. However, the dimensional shape and the arrangement relationship in each drawing used for the description are also schematic. That is, the present invention is not limited to this embodiment.

For example, the beam separation / shaping element in the laser processing method and laser processing apparatus according to the present invention is not limited to the above-described configuration, and may be configured not only before and after the objective lens 11 but also in the surrounding optical system. Various configurations can be adopted, and energy adjustment of each pulse laser beam can be performed in the configuration.
Further, for example, the stage 12 can be replaced with a fixing jig, and the processing method according to the present invention can be applied to a member processed in advance with a laser beam having a pulse width of nanosecond order.

Further, the irradiation of the first and second pulse laser beams in parallel in time or space may be performed in time, for example, simultaneously with each other, or spatially, for example, at positions close to each other. However, the present invention is not limited to this, and for example, irradiation performed based on a selected time difference, or irradiation performed at a predetermined interval (for example, 10 μm or less) corresponding to the time difference can be used.
Further, in the laser processing method according to the present invention, at least the irradiation with the second pulse laser beam can be performed under a reduced pressure condition, and the gas blowing means and the gas suction means described above are only one of them. The present invention can be variously modified and modified such that the gas suction means can also serve as the pressure reducing means.

It is a schematic diagram which shows the structure of an example of the laser processing apparatus which concerns on this invention. It is a schematic diagram which shows the structure of the beam separation shaping element in an example of the laser processing apparatus which concerns on this invention. A and B are schematic views each showing a specific example of a configuration of a beam separation shaping element in an example of a laser processing apparatus according to the present invention. It is a schematic diagram with which it uses for description of an example of the laser processing method which concerns on this invention. It is a schematic diagram which shows the structure of the other example of the laser processing apparatus which concerns on this invention. A and B are photographs used to explain examples of the laser processing method according to the present invention. A and B are photographs used to explain examples of the laser processing method according to the present invention. A and B are photographs used to explain a conventional laser processing method. A and B are photographs used to explain a conventional laser processing method. A and B are photographs used to explain a conventional laser processing method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus, 2 ... Light source system, 3 ... Optical system, 4 ... Irradiation system, 5 ... Work piece (object to be irradiated), 6 ... Light source, 7 .. Lens, 8... Mirror, 9... Optical element for focus adjustment, 9 a... Lens, 9 b. ..Stage, 13... Member to be processed (irradiated body), 14... Gas blowing means, 15... Gas suction means, 16 a... First cylindrical lens, 16 b. Cylindrical lens, 17 ... diffraction grating, 18 ... mask for beam splitting, 19 ... condensing lens, 20a ... first cylindrical lens, 20b ... second cylindrical lens, 21 ... Main light source 22 ... auxiliary light source 23 ... amplifier 24 ..Mirror, 25 ... Adjuster, 31 ... ND filter, 32 ... Mirror, 33 ... Mirror, 34 ... Afocal optical system, 35 ... Lens, 36 ... Slit 37 ... Lens, 41 ... Mirror, 42 ... Beam splitter, 43 ... Objective lens, 44 ... Stage, 45 ... Illumination light source, 46 ... Filter

Claims (6)

A first pulse laser beam having a pulse width of less than 10 picoseconds and evaporating the workpiece;
The pulse width is less than 10 picoseconds, the first pulse laser beam is sandwiched between the front and rear in the scanning direction , and the irradiation region is formed so as not to overlap the irradiation region of the first pulse laser beam. A second pulse laser beam that deforms the irradiated portion by expansion;
Is formed by dividing a common laser beam, and the irradiation with the first pulse laser beam and the second pulse laser beam is performed in parallel.   The laser processing method according to claim 1, wherein at least the irradiation with the second pulsed laser light is performed by generating an air flow in the irradiated portion of the workpiece.   The laser processing method according to claim 1, wherein at least the irradiation with the second pulse laser beam is performed under a reduced pressure condition.   The laser processing method according to claim 1, wherein at least the irradiation with the second pulse laser beam is performed using an optical system having a numerical aperture of 0.01 or more and less than 1.0. A light source that emits a pulse laser beam of less than 10 picoseconds;
A beam separation shaping element that separates laser light from the light source into a plurality of laser lights;
An objective lens that focuses the plurality of separated laser beams on a workpiece; and
The beam separating and forming element separates the first pulse laser beam for evaporating the material of the workpiece and the front and rear with respect to the scanning direction across the first pulse laser beam , and the irradiation region Is formed so as not to overlap with the irradiation region of the first pulse laser beam, and forms a second pulse laser beam that deforms the irradiated portion by expansion.   The said beam separation shaping | molding element contains the mask which divides | segments the laser beam radiate | emitted from the said light source into a several laser beam, and the cylindrical lens arrange | positioned on the optical path of the said divided | segmented laser beam. Laser processing equipment.