JP6788182B2 - Laser processing equipment and laser processing method - Google Patents

Description

The present invention relates to a laser processing apparatus and a processing method for processing an workpiece using laser light.

Conventionally, in order to divide a wafer on which semiconductor devices and electronic components are formed into individual chips, a blade dicing device that cuts the wafer by rotating a thin grindstone at high speed or a laser is focused inside the wafer. A laser dicing device that cuts by forming a modified region has been used.

In recent years, wafers with inorganic or organic films and metal patterns have been put into practical use, and there is a problem that they are peeled off during processing by the above dicing apparatus and the quality is deteriorated. There is.

In order to eliminate the peeling, a laser processing device that removes various films and metal patterns in advance is used prior to the dicing process.

Such a laser processing device includes a direct condensing method (Patent Document 1) in which laser light is directly focused and irradiated on a work piece, or a pressurized liquid is jetted as a liquid jet and used as a waveguide for a laser. A liquid jet method (Patent Document 2) of irradiating a work piece with light is known.

Japanese Patent No. 4777783 Japanese Patent No. 5072691

By the way, each of the above two methods of a laser processing apparatus has the following merits and demerits, and the current situation is that they are used properly according to the application.

FIG. 11 is a diagram showing the advantages and disadvantages of the direct condensing method and the liquid jet method of the laser processing apparatus.

As shown in FIG. 11, in the direct condensing method, there is a degree of freedom in the size of the condensing spot (condensing point), and energy can be concentrated in an arbitrary region to process the workpiece. The problem of peeling of various films and metal patterns can be solved, for example, by cutting both ends of the planned processing region into thin edges in advance. However, a part of the work piece that has been processed and becomes hot is scattered, welded, and adhered to the surroundings as debris, which causes a problem of deteriorating the quality. This can be avoided by applying a protective film to the surface of the work piece, but the throughput decreases and the cost increases due to the application process and the removal process. In addition, heat generated during machining may propagate from the machining region to the outer peripheral portion, causing an unintended thermal effect on the device surface or the inside of the substrate.

On the other hand, in the liquid jet method, debris scattering is suppressed because it is covered with liquid at the same time as processing. Further, since the heat of the processing region and the debris is cooled by the liquid jet, the welding of the debris and the heat influence on the outer peripheral portion are suppressed. However, depending on the material and structure of the workpiece, there is a problem that the surface layer film is peeled off to the outer peripheral portion of the processed region, resulting in deterioration of quality.

The present invention has been made in view of such circumstances, and can suppress the effects of film peeling, debris, and heat caused by laser processing, do not require a protective film, and ensure high processing quality. It is an object of the present invention to provide a laser processing apparatus and a laser processing method.

In order to achieve the above object, the laser processing apparatus according to the first aspect of the present invention includes a laser light source that emits processing laser light, a processing unit that laser-processes an workpiece using the processing laser light, and the like. It is a laser processing apparatus having a moving means for relatively moving the processing unit and the workpiece, and the processing unit uses the processing laser light emitted from the laser light source as a first laser light and a second laser light. The light branching means for branching to and the workpiece which is moved relative to the machining unit in the first direction by the moving means are orthogonal to the first direction of the planned machining region along the first direction. A direct condensing means for condensing the first laser light inside the workpiece at the outer edges on both sides in the two directions, and a workpiece that moves relative to the machining unit in the first direction by the moving means. On the other hand, with a processing head that injects pressurized liquid with a liquid jet and uses the liquid jet as a waveguide to irradiate the inner region sandwiched between the outer edges on both sides of the planned processing region with a second laser beam. , Equipped with.

In the first aspect of the laser processing apparatus according to the second aspect of the present invention, the direct condensing means branches and condenses the first laser light inside the workpiece at the outer edges on both sides of the planned processing region. It has a light collecting means.

In the second aspect of the laser processing apparatus according to the third aspect of the present invention, the branch condensing means has two branches and focused first laser light according to the width of the planned processing region in the second direction. The distance of the focusing point in the second direction can be adjusted.

In the second aspect of the laser processing apparatus according to the fourth aspect of the present invention, the branch condensing means comprises a spatial light modulator.

In the laser processing apparatus according to the fifth aspect of the present invention, in the first aspect, in the direct condensing means, the first laser beam is temporally deviated from the inside of the workpiece at the outer edges on both sides of the planned processing region. It has a light deflecting means for deflecting the first laser beam so as to scan alternately at the timing.

In the laser processing apparatus according to the sixth aspect of the present invention, in the fifth aspect, the light deflection means comprises an acoustic optical element.

The laser processing method according to the seventh aspect of the present invention refers to the first direction of the planned processing region along the first direction with respect to the workpiece that moves relative to the direct condensing means in the first direction. A first laser processing step of condensing the first laser beam directly inside the workpiece at the outer edges on both sides in the second direction orthogonal to the processing head by a condensing means, and a first direction with respect to the processing head. A pressurized liquid is jetted from the machining head to the workpiece that moves relative to the machining object, and the liquid jet is used as a waveguide to apply a second laser beam to the outer edges on both sides of the planned machining region. It comprises a second laser processing step of irradiating the sandwiched inner region.

In the seventh aspect, the laser processing method according to the eighth aspect of the present invention includes an optical branching step of branching the processing laser light emitted from the laser light source into a first laser light and a second laser light.

In the eighth aspect of the laser processing method according to the ninth aspect of the present invention, in the first laser processing step, the first laser light is branched and focused inside the workpiece at the outer edges on both sides of the planned processing region. It has a branch focusing process.

In the ninth aspect of the laser processing method according to the tenth aspect of the present invention, the branch focusing step consists of two branches and focused first laser light according to the width of the planned processing region in the second direction. It has an adjustment step of adjusting the distance of the focusing point in the second direction.

In the ninth aspect of the laser processing method according to the eleventh aspect of the present invention, in the branch focusing step, the first laser light is branched and focused using a spatial light modulator.

According to the twelfth aspect of the present invention, in the seventh aspect, in the first laser processing step, the first laser beam temporally moves the inside of the workpiece at the outer edges on both sides of the planned processing region. It has a light deflection step of deflecting the first laser beam so that the scanning is performed alternately at different timings.

In the twelfth aspect of the laser processing method according to the thirteenth aspect of the present invention, the light deflection step deflects the first laser beam by using an acoustic optical element.

According to the present invention, it is possible to suppress the effects of film peeling, debris, and heat caused by laser processing, eliminate the need for a protective film, and ensure high processing quality.

Schematic diagram showing the configuration of the laser processing apparatus of the first embodiment Schematic diagram showing a state when the work piece is irradiated with the first processing light in the direct condensing method processing in the first embodiment. The figure for demonstrating the effect when the branch condensing means is rotated in the θ direction. Schematic diagram showing a state when a liquid jet is injected onto a work piece in the liquid jet method processing in the first embodiment. Schematic diagram showing the state after the workpiece is processed by the second processing light induced by using the liquid jet as a waveguide. The figure for demonstrating the effect of the laser processing method in 1st Embodiment , A flowchart showing a laser processing method using the laser processing apparatus of the first embodiment. Schematic diagram showing the laser processing apparatus of the second embodiment Schematic diagram showing the laser processing apparatus of the third embodiment Schematic diagram showing the laser processing apparatus of the fourth embodiment Diagram showing the advantages and disadvantages of the direct condensing method and the liquid jet method of the laser processing device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
First, the first embodiment will be described.

FIG. 1 is a schematic view showing the configuration of the laser processing apparatus 10 of the first embodiment.

As shown in FIG. 1, the laser processing apparatus 10 of the first embodiment includes a laser light source 12, an Xθ stage 14, a liquid supply means 16, a processing unit 30, an autofocus device (AF device) 70, and the like. It includes a control unit 72.

The laser light source 12 emits a processing laser beam L1 for processing the workpiece W. As the processing laser beam L1, a laser beam in a wavelength range that is difficult to be absorbed by water is used. In the present embodiment, preferable conditions for the processing laser beam L1 are a wavelength in the UV wavelength range (less than 400 nm), a pulse width of 1 μs or less, a repetition frequency of more than 1 kHz, and an average output of 0.01 to 10 W. The spot diameter at the condensing point of the direct condensing method is 0.23 to 10 μm.

The Xθ stage 14 attracts and fixes the work piece W, and is configured to be movable in the X direction and rotatable in the θ direction by a stage drive mechanism (not shown). The stage drive mechanism is controlled based on a control signal from the control unit 72. The stage moving mechanism and the processing unit drive mechanism described later are examples of moving means.

In FIG. 1, the X, Y, and Z directions are orthogonal to each other, the X direction is the horizontal direction, the Y direction is the horizontal direction orthogonal to the X direction, and the Z direction is the vertical direction. The X direction is an example of the first direction, and the Y direction is an example of the second direction. Further, the θ direction is a rotation direction around the Z direction. Further, the workpiece W is composed of a base material layer 20, an intermediate layer 21, and a surface film 22 in this order from the Xθ stage 14 side (see FIG. 2).

The liquid supply means 16 supplies the pressurized liquid into the processing head 60 (liquid chamber 66) described later. The liquid supply means 16 is not particularly limited, and a known means, a known device, or the like can be used. For example, pure water stored in the tank may be supplied by a high-pressure pump.

The machining unit 30 is arranged above the Xθ stage 14, and is configured to be movable in the Y direction and the Z direction by a machining unit drive mechanism (not shown). The processing unit drive mechanism is controlled based on the control signal output from the control unit 72.

The processing unit 30 is composed of a hybrid system in which a direct condensing system and a liquid jet system are used in combination. According to this configuration, as will be described in detail later, it is possible to enjoy the merits of the direct condensing method and the liquid jet method and improve the processing quality.

The processing unit 30 includes a light amount adjusting means 32, a polarization adjusting means 34, a polarization beam splitter 36, a dichroic mirror 38, a branch condensing means 40, a mirror 42, a beam shape shaping means 44, and a processing head 60. It has. In the present embodiment, the processing unit 30 is provided with the laser light source 12 and the AF device 70, but the laser light source 12 and the AF device 70 may be provided separately from the processing unit 30.

The processing laser beam L1 emitted from the laser light source 12 passes through the light amount adjusting means 32 and the polarization adjusting means 34 in sequence, and enters the polarization beam splitter 36.

The light amount adjusting means 32 is arranged on the emitting side of the laser light source 12, and adjusts the light amount of the processing laser light L1 emitted from the laser light source 12. Examples of the light amount adjusting means 32 include an aperture in which the size of the light passing range is variable, a combination of a 1/2 wave plate (λ / 2 plate) and a polarizing element, or a variable ND filter having a different light transmission efficiency. Can be configured using.

The polarization adjusting means 34 adjusts the polarization direction of the processing laser beam L1, and is composed of, for example, a 1/2 wavelength plate.

The polarization beam splitter 36 splits the incident laser beam L1 for processing by polarization at the deflection separation surface (joint surface) 36a. As a result, the processing laser light L1 incident on the polarizing beam splitter 36 includes the first processing light L1s (S-polarized light) reflected by the polarization separation surface 36a and the second processing light (P-polarized light) transmitted through the polarization separation surface 36a. It is branched into (optical) L1p (optical branching step). The polarization beam splitter 36 is an example of optical branching means. The first processed light L1s is an example of the first laser beam, and the second processed light L1p is an example of the second laser beam.

The first processed light L1s emitted from the polarizing beam splitter 36 passes through the dichroic mirror 38 and enters the branch condensing means 40.

The dichroic mirror 38 transmits light in the first wavelength region and reflects light in a second wavelength region different from the first wavelength region. In this example, the first wavelength region includes the wavelength of the processing laser light L1 emitted from the laser light source 12 (less than 400 nm), and the second wavelength region includes the wavelength of the AF light L2 emitted from the AF device 70 (400 nm or more). )including. As a result, the first processed light L1s emitted from the polarizing beam splitter 36 passes through the dichroic mirror 38 and is incident on the branch condensing means 40. Then, the first processed light L1s is condensed by the branch condensing means 40 and irradiated to the workpiece W. Further, the AF light L2 emitted from the AF device 70 is reflected by the dichroic mirror 38, condensed by the branch condensing means 40 and irradiated to the workpiece W, and the AF light reflected by the workpiece W. The reflected light of L2 is returned to the AF device 70 via the reverse path and detected.

The branch condensing means 40 is configured to include, for example, a diffraction grating and a lens, condenses the incident first processed light L1s at a predetermined height position (Z direction position), and has a plurality of condensing points. Branch. That is, the branch condensing means 40 branches and condenses the first processed light L1s. In the present embodiment, as will be described later, the branch condensing means 40 branches and condenses the first processed light L1s to two condensing points P1 and P2 (see FIG. 2). The number of focusing points that are branched and focused may be three or more. The branched light collecting means 40 is an example of the direct light collecting means.

The branch condensing means 40 is configured to be rotatable in the θ direction and movable in the Z direction with respect to the optical axis by a rotational movement mechanism (not shown). The rotational movement mechanism is controlled based on the control signal output from the control unit 72, and drives the branch condensing means 40 to rotate in the θ direction or move in the Z direction (vertical direction). As a result, as will be described later, the branch condensing means 40 can be moved in the Z direction according to the change in the relative distance between the workpiece W and the machining unit 30, thereby processing the workpiece W and the machining unit 30. It is possible to keep the relative distance to the unit 30 constant. Further, by rotating the branch condensing means 40 in the θ direction, the branch collection is performed according to the processing width (width in the Y direction) of the planned processing region R (see FIG. 2) along the X direction of the workpiece W. It is possible to adjust the distance (distance in the Y direction) between the two focusing points P1 and P2 that have been branched and focused by the optical means 40.

On the other hand, the second processing light L1p emitted from the polarization beam splitter 36 is reflected by the mirror 42, shaped into a desired beam shape by the beam shape shaping means 44, and then incident on the processing head 60.

The beam shape shaping means 44 includes, for example, an aperture (rectangular aperture, circular aperture), an axicon lens, a beam homogenizer, a diffraction grating, a lens, and the like, and has a beam shape, size, and intensity distribution of the second processed light L1p. Shape the ray angle etc. to any one.

The processing head 60 injects the pressurized liquid supplied from the liquid supply means 16 by the liquid jet J, and uses the liquid jet J as a waveguide to use the second processing light L1p as the processing scheduled region of the workpiece W. Irradiate R. The specific configuration of the processing head 60 is as follows.

The processing head 60 includes a condenser lens 62, a transmission glass 64, a liquid chamber 66, and a liquid jet injection nozzle 68.

The condensing lens 62 condenses the second processed light L1p incident on the processing head 60 into the orifice (nozzle hole) of the liquid jet injection nozzle 68.

The transmission glass 64 is arranged between the condensing lens 62 and the liquid chamber 66, and is configured as a partition portion that seals the pressurized liquid supplied from the liquid supply means 16 inside the liquid chamber 66. Further, the transparent glass 64 is formed of a light transmitting member (for example, quartz glass) that transmits the second processed light L1p. As a result, the second processed light L1p emitted from the condenser lens 62 passes through the transmission glass 64 and is guided to the inside of the liquid chamber 66.

The liquid chamber 66 is a liquid accommodating portion that seals the pressurized liquid supplied from the liquid supply means 16, and the wall surface on the incident surface side (upper surface side in FIG. 1) of the second processing light L1p is formed by the above-mentioned transparent glass 64. It is configured.

The liquid jet injection nozzle 68 is arranged at a position facing the workpiece W in the machining head 60 and communicates with the liquid chamber 66. As a result, the pressurized liquid contained in the liquid chamber 66 is ejected from the liquid jet injection nozzle 68 toward the workpiece W as a liquid jet J. Further, since the second processed light L1p is condensed in the orifice of the liquid jet injection nozzle 68 through the condenser lens 62 and the transmission glass 64, the second processed light is contained in the liquid jet J ejected from the liquid jet injection nozzle 68. L1p is guided. As a result, the second processed light L1p is guided by the liquid jet J and irradiates the workpiece W.

Although details are omitted, it is known that the processing performance is improved by supplying the gas fluid so as to include the liquid jet J (see Japanese Patent No. 5437578).

The AF device 70 includes an autofocus light source (AF light source) (not shown) that emits light in a wavelength region (second wavelength region) different from that of the processing laser light L1 as AF light. In this embodiment, light having a wavelength of 400 nm or more is used as the AF light. The AF light L2 emitted from the AF light source is reflected by the dichroic mirror 38, condensed by the branch condensing means 40, and irradiated to the workpiece W. Then, the reflected light of the AF light L2 from the workpiece W enters the AF device 70 via the reverse path. The AF device 70 detects the reflected light of the AF light L2 from the workpiece W with a photodetector provided with a plurality of light receiving elements, and determines the relative distance (height) between the workpiece W and the machining unit 30. The corresponding detection signal (autofocus signal) is output to the control unit 72. Since the configuration of such an AF device 70 is well known, detailed description thereof will be omitted.

The control unit 72 includes a CPU, a memory, an input / output circuit unit, various control circuit units, and the like, and controls the operation of each unit of the laser processing apparatus 10. That is, the control unit 72 performs various controls of the laser processing apparatus itself, such as light emission control of the laser light source 12, movement control of the Xθ stage 14 and the processing unit 30, liquid supply control of the liquid supply means 16.

Further, the control unit 72 controls the focusing point (focus control) of the branch focusing means 40. Specifically, the control unit 72 of the branch condensing means 40 so that the relative distance (height) between the workpiece W and the processing unit 30 is constant based on the detection signal output from the AF device 70. Controls the rotational movement mechanism. Further, the control unit 72 has two focusing points P1 and P2 that are branched and focused by the branch focusing means 40 based on the machining conditions (including the machining width of the planned machining region) input from the input unit (not shown). The rotational movement mechanism of the branch condensing means 40 is controlled to rotate the branch condensing means 40 in the θ direction so that the interval (distance in the Y direction) corresponds to the machining width of the planned machining area R.

With the above configuration, in the laser processing method using the laser processing apparatus 10 of the first embodiment, the workpiece W is processed by the direct condensing method using the first processing light L1s (direct condensing method processing). ) Is performed, then processing by the liquid jet method (liquid jet method processing) is performed using the second processing light L1p.

FIG. 2 is a schematic view showing a state when the work piece W is irradiated with the first processing light L1s in the direct condensing method processing in the first embodiment. It is assumed that the planned processing region R of the workpiece W is formed along the X direction.

As shown in FIG. 2, in the direct condensing method processing in the first embodiment, the first processed light L1s incident on the branch condensing means 40 while processing and feeding the workpiece W in the X direction by the Xθ stage 14 Is branched and condensed to two different focusing points P1 and P2 inside the workpiece W (that is, a position below the surface of the workpiece W) by the branched focusing means 40. Specifically, the branch condensing means 40 branches and condenses two condensing points P1 and P2 inside the surface film 22 at the outer edges on both sides in the Y direction of the planned processing region R of the workpiece W. As a result, the modified layers 24a and 24b having a predetermined depth are formed inside the surface film 22 at the outer edges on both sides of the planned processing region R. It is assumed that the amount of light of the first processed light L1s is adjusted by the light amount adjusting means 32 so as to be a desired amount of light (the amount of light capable of forming the modified layers 24a and 24b inside the surface film 22).

FIG. 3 is a diagram for explaining the effect when the branch condensing means 40 is rotated in the θ direction.

When the branch condensing means 40 is rotated in the θ direction, as shown in FIG. 3, two condensing points of the first processed light L1s that are branched and condensed by the branch condensing means 40 (not shown in FIG. 3). The positional relationship between P1 and P2 changes. Along with this, the distance (width) M in the Y direction of the two focusing points P1 and P2 changes, and as shown in FIG. 3A, the condition that the distance M in the Y direction is relatively wide and FIG. 3 ( As shown in b), it is possible to create a condition in which the interval M in the Y direction is relatively narrow.

In the direct condensing method processing in the first embodiment, by rotating the branch condensing means 40 in the θ direction, the distance M between the two condensing points P1 and P2 in the Y direction is set to the processing width of the planned processing region R. It is possible to adjust accordingly. As a result, even when the processing width of the planned processing region R is different, the branch condensing means 40 is rotated in the θ direction to change the distance M between the two condensing points P1 and P2 in the Y direction, as shown in FIG. As shown, it is possible to form the modified layers 24a and 24b having a predetermined depth inside the surface film 22 at the outer edges on both sides of the planned processing region R.

FIG. 4 is a schematic view showing a state when the liquid jet J is injected to the workpiece W in the liquid jet method processing according to the first embodiment. FIG. 5 is a schematic view showing a state after the workpiece W is processed by the second processing light L1p guided by the liquid jet J.

As shown in FIG. 4, the liquid jet processing in the first embodiment is performed after the direct condensing processing described above is performed. That is, after the modified layers 24a and 24b having a predetermined depth are formed inside the surface film 22 at the outer edges on both sides of the planned processing region R by the direct condensing method processing, the workpiece W is moved in the X direction by the Xθ stage 14. The liquid jet J is ejected from the processing head 60 toward the inner region sandwiched between the outer edges on both sides of the planned processing region R while being processed and fed. As a result, the inner region of the planned processing region R is irradiated with the second processing light L1p guided by the liquid jet J. As a result, as shown in FIG. 5, the surface film 22 and the intermediate layer 21 in the inner region of the planned processing region R are removed, and the workpiece W has a predetermined depth (base material layer 20) along the planned processing region R. A processing groove 26 having a depth reaching up to) is formed.

FIG. 6 is a diagram for explaining the effect of the laser processing method in the first embodiment, and is a diagram showing the processing results when the direct condensing method processing and the liquid jet method processing are combined. Here, in order to explain the effect of the laser processing method in the first embodiment in an easy-to-understand manner, a single condensing lens is used instead of the branch condensing means 40, and the outer edges on both sides of the planned processing region R are used. A case will be described in which the first processing light L1s is condensed inside the surface film 22 at only one of the outer edge portions and the direct focusing method processing is performed.

As shown in FIG. 6A, a modified layer 24a having a predetermined depth is formed inside the surface film 22 by direct condensing processing only on one of the outer edges on both sides of the planned processing region R. When the liquid jet method processing is performed on the inner region of the planned processing region R after the formation, the processing result is as shown in FIG. 6 (b). That is, on the side where the modified layer 24a is formed (the side with edge cutting), the edge is cut by the modified layer 24a, so that the peeling of the film outside the planned processing region R is blocked, but the opposite side. On the (non-edge cutting side), since there is no modified layer as described above and the edge is not cut, the peeling of the film outside the planned processing region R is widely spread.

As can be seen from the processing results shown in FIG. 6, after forming the modified layers 24a and 24b having a predetermined depth inside the surface film 22 by direct condensing processing on the outer edges on both sides of the planned processing region R, By machining the inner region of the planned machining region R by the liquid jet method machining, it is possible to effectively suppress the influence of film peeling, debris, and heat caused by laser machining, and improve the machining quality.

FIG. 7 is a flowchart showing a laser processing method using the laser processing apparatus 10 of the first embodiment. Unless otherwise specified, each process is executed under the control of the control unit 72.

First, before starting the processing of the workpiece W, the adjustment step for direct condensing method processing for performing the direct condensing method processing in the laser processing apparatus 10 is performed (step S10). Here, it is assumed that the operation mode of the laser processing apparatus 10 is set to the direct condensing method processing.

In the adjustment step for direct condensing method processing, the light amount adjusting means 32 is operated to generate a laser light source so that the first processed light L1s and the second processed light L1p, which are polarized and separated by the polarizing beam splitter 36, have desired light amounts. The amount of light of the processing laser light L1 emitted from 12 is adjusted, and the polarization direction of the processing laser light L1 is adjusted by operating the polarization adjusting means 34.

Further, the distance M in the Y direction between the two focusing points P1 and P2 of the first processed light L1s collected by the branch condensing means 40 is adjusted so as to be an interval corresponding to the processing width of the planned processing region R. .. For example, in the control unit 72, based on the processing width of the scheduled processing region R input via an input unit (not shown), the distance M between the two focusing points P1 and P2 in the Y direction becomes the processing width of the scheduled processing region R. The branch condensing means 40 may be rotated in the θ direction by a rotational movement mechanism so as to have a corresponding interval. Further, the branch condensing means 40 is manually rotated in the θ direction so that the distance M between the two condensing points P1 and P2 in the Y direction is adjusted so as to correspond to the processing width of the planned processing region R. It may be. As a result, the distance M between the two light collection points P1 and P2 in the Y direction is set to a distance corresponding to the processing width of the planned processing region R.

Next, an alignment step (step S12) is performed by an alignment device (not shown) to perform relative alignment between the workpiece W placed (suction-fixed) on the Xθ stage 14 and the processing unit 30 (step S12).

Next, after moving the machining unit 30 to a predetermined height position (Z direction position) with respect to the workpiece W, the branch condensing means 40 of the machining unit 30 faces the scheduled machining region R to be machined. The machining unit 30 is indexed and fed in the Y direction so as to be (step S14).

Next, the direct condensing method processing step by the first processing light L1s is performed on the workpiece W while processing and feeding the Xθ stage 14 in the X direction (step S16). The direct condensing method processing process is an example of the first laser processing process.

In the direct condensing method processing step, the first processed light L1s reflected by the polarization separating surface 36a of the polarization beam splitter 36 is incident on the branch condensing means 40 via the dichroic mirror 38. Then, the first processed light L1s is condensed from the branch condensing means 40 to two condensing points P1 and P2 which are different from each other in the Y direction inside the surface film 22 (branching condensing step). As a result, the modified layers 24a and 24b having a predetermined depth are formed inside the surface film 22 at the outer edges on both sides of the planned processing region R. Before the liquid jet method processing is performed in this way, the surface film 22 at the outer edges on both sides of the planned processing area R is edge-cut by the direct condensing method processing, which is a disadvantage in the liquid jet method processing. It is possible to effectively suppress the peeling of the film.

In the present embodiment, the first processed light L1s is simultaneously focused on two focusing points P1 and P2 different from each other in the Y direction by the branch focusing means 40, so that the outer edges on both sides of the planned processing region R are passed by one path. Since it can be processed by (one processing feed), the processing efficiency can be improved.

Further, in the present embodiment, at the same time that the direct condensing method processing is performed, the AF device 70 and the control unit 72 control so that the relative distance between the processing unit 30 and the workpiece W becomes constant. .. That is, the AF device 70 detects the reflected light of the AF light L2 applied to the workpiece W via the dichroic mirror 38 and the branch condensing means 40, and the relative distance between the machining unit 30 and the workpiece W. The detection signal corresponding to the above is output to the control unit 72. The control unit 72 feedback-controls the rotation and vertical movement mechanism of the branch condensing means 40 so that the relative distance between the processing unit 30 and the workpiece W is constant. As a result, the relative distance between the processing unit 30 and the workpiece W becomes constant, so that the first processing light L1s is constant without being affected by the change in the relative distance between the processing unit 30 and the workpiece W. Since the condensing state is maintained, high-precision and high-quality processing is possible in the direct condensing method.

After the direct condensing method machining for one scheduled machining area R is completed in this way, a determination step of determining whether or not the machining of all the scheduled machining areas R is completed is performed (step S18).

If it is determined in the determination step of step S18 that the machining of all the scheduled machining regions R has not been completed, the machining unit 30 is indexed and fed in the Y direction with an index feed amount corresponding to the interval of the scheduled machining regions R. Then (step S14), with the branch condensing means 40 of the processing unit 30 positioned at a position facing the adjacent scheduled processing region R, the direct condensing method processing is performed while the Xθ stage 14 is processed and fed in the X direction. It is performed (step S16). Further, if the indexing feed in the Y direction and the machining feed in the X direction are alternately repeated and the direct condensing method machining is performed on all of the planned machining regions R parallel to the X direction, the Xθ stage 14 is moved in the θ direction. The planned processing area R, which is rotated by 90 ° and is orthogonal to the planned processing area R, is also subjected to direct light collection method processing in the same manner.

On the other hand, when it is determined in the determination step of step S18 that the processing of all the planned processing areas R has been completed, the operation mode of the laser processing apparatus 10 is changed from the direct condensing method processing to the liquid jet method processing. (Step S20).

Next, after the machining unit 30 is moved to a predetermined height position (Z direction position) with respect to the workpiece W, the machining head 60 (liquid jet injection nozzle 68) of the machining unit 30 is the scheduled machining region R to be machined. The machining unit 30 is indexed and fed in the Y direction so as to face the position (step S22).

Next, a liquid jet processing step is performed on the workpiece W by the second processing light L1p while processing and feeding the Xθ stage 14 in the X direction (step S24). The liquid jet machining process is an example of the second laser machining process.

In the liquid jet method processing step, the pressurized liquid in the liquid chamber 66 supplied from the liquid supply means 16 is ejected as the liquid jet J from the liquid jet injection nozzle 68. Further, the second processing light L1p transmitted through the polarization separation surface 36a of the polarization beam splitter 36 is incident on the processing head 60 via the mirror 42 and the beam shape shaping means 44. The second processed light L1p incident on the processing head 60 enters the orifice of the liquid jet injection nozzle 68 via the condenser lens 62, the transmission lens 64, and the liquid chamber 66. As a result, the second processed light L1p is guided to the liquid jet injection nozzle 68, and is guided to the workpiece W while repeating total internal reflection in the liquid jet J using the liquid jet J as a waveguide, and is processed. The inner region of the planned processing region R of the object W is irradiated. As a result, as shown in FIG. 5, the surface film 22 and the intermediate layer 21 in the inner region of the planned processing region R are removed, and the workpiece W has a predetermined depth (base material layer) along the planned processing region R. A processing groove 26 having a depth of up to 20) is formed.

When the liquid jet method machining for one scheduled machining area R is completed in this way, a determination step of determining whether or not the machining of all the scheduled machining areas R is completed is performed (step S26).

If it is determined in the determination step of step S26 that the machining of all the scheduled machining regions R has not been completed, the machining unit 30 is indexed and fed in the Y direction with an index feed amount corresponding to the interval of the scheduled machining regions R. Then (step S22), with the machining head 60 (liquid jet injection nozzle 68) of the machining unit 30 positioned at a position facing the adjacent scheduled machining region R, the liquid is machined while feeding the Xθ stage 14 in the X direction. Jet processing is performed (step S24). In this way, the indexing feed in the Y direction and the machining feed in the X direction are alternately repeated, and after liquid jet machining is performed on all of the planned machining regions R parallel to the X direction, the Xθ stage 14 is moved. The liquid jet method machining is performed in the same manner in the scheduled machining area R which is rotated by 90 ° in the θ direction and is orthogonal to the scheduled machining area R.

On the other hand, in the determination step of step S26, when it is determined that the machining of all the scheduled machining regions R has been completed, this flowchart ends.

Next, the effect of the first embodiment will be described.

According to the first embodiment, the outer edges on both sides of the planned processing area R are processed by the direct condensing method, and then the inner region sandwiched between the outer edges on both sides of the planned processing area R is processed by the liquid jet method. To do. At that time, in the processing by the direct condensing method, the inside (surface) of the work piece W, which is located below the surface of the work piece W, is not ablated to the surface of the work piece W. Since the modified layers 24a and 24b are formed on the inside of the film 22), it is possible to suppress the occurrence of debris. Further, since the processing is performed by the liquid jet method after the edge cutting, it is possible to effectively suppress the peeling of the film and the influence of heat caused by the laser processing and improve the processing quality.

Further, in the first embodiment, the processing laser light L1 emitted from the laser light source 12 is branched into the first processing light L1s and the second processing light L1p by the deflection beam splitter 9, and is directly collected by the first processing light L1s. Optical processing and second processing Liquid jet processing using optical L1p and a single device. Therefore, it is possible to reduce the size and cost of the device, and if the alignment is performed only once in the direct condensing method processing, the alignment can be omitted in the subsequent liquid jet method processing, and the overall throughput is improved. Can be made to.

Further, in the first embodiment, since the first processed light L1s is branched and condensed to the two focusing points P1 and P2 by the branched condensing means 40, the edges on both sides of the planned processing region R are one. It can be processed with a pass, and processing efficiency can be improved.

Further, in the first embodiment, the branch condensing means 40 is configured to be rotatable in the θ direction (rotational direction around the optical axis), and the two condensing points P1 that are branched and condensated by the branch condensing means 40. The interval M in the Y direction of P2 can be adjusted so as to correspond to the processing width of the planned processing area R. As a result, any scheduled machining area R can be machined in one pass without being affected by the machining width of the scheduled machining area R, and the machining efficiency and the degree of freedom of machining can be increased.

Further, in the first embodiment, the AF device 70 and the control unit 72 control the relative distance between the machining unit 30 and the workpiece W to be constant, so that the machining quality is kept constant within the machining region. be able to.

(Second Embodiment)
Next, the second embodiment will be described.

FIG. 8 is a schematic view showing the laser processing apparatus 10A of the second embodiment. In FIG. 8, components common to or similar to those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the first embodiment, the first processed light L1s is branched and condensed at two different focusing points P1 and P2 by the branched focusing means 40, whereas in the second embodiment, the branched focusing is performed. Instead of the means 40, a single condenser lens 46 is provided.

The laser processing apparatus 10A of the second embodiment is basically the same as that of the first embodiment except that the condensing lens 46 is provided instead of the branch condensing means 40.

As shown in FIG. 8, the condenser lens 46 in the second embodiment is configured to be movable in the Z direction by a moving mechanism (not shown). The moving mechanism is controlled based on the control signal output from the control unit 72, and drives the condenser lens 46 to move in the Z direction (vertical direction). As a result, as in the first embodiment, the AF device 70 and the control unit 72 control the machining unit 30 so that the relative distance between the workpiece W and the workpiece W is constant.

Further, the condensing lens 46 in the second embodiment condenses the first processed light L1s to one condensing point. Therefore, in the laser processing method using the laser processing apparatus 10A of the second embodiment, when the direct condensing method processing is performed on the planned processing area R, one of the outer edge portions on both sides of the planned processing area R is used. After forming the modified layer 24a by aligning the condensing points of the condensing lens 46 inside the surface film 22 at the outer edge portion, the condensing points of the condensing lens 46 are aligned inside the surface film 22 at the other outer edge portion. It is necessary to form the modified layer 24b.

That is, in the second embodiment, two passes are required instead of one in order to form the modified layers 24a and 24b on the outer edges on both sides of the planned processing region R by the direct condensing method processing, respectively. Will be done. However, also in the second embodiment, the modified layers 24a and 24b are formed inside the surface films 22 at the outer edges on both sides of the planned processing region R by the direct condensing method processing, and then the liquid jet method processing is performed. Since the inner region of the planned machining region R is machined, it is possible to effectively suppress the effects of film peeling, debris, and heat caused by laser machining and improve the machining quality, as in the first embodiment. It becomes.

(Third Embodiment)
Next, a third embodiment will be described.

FIG. 9 is a schematic view showing the laser processing apparatus 10B of the third embodiment. In FIG. 9, components common to or similar to those in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted.

In addition to the configuration of the second embodiment, the third embodiment further includes an AOD (acoustic optical element) 48 arranged between the polarizing beam splitter 36 and the dichroic mirror 38.

The AOD48 deflects the incident first processed light L1s at a specific angle and a specific frequency. In the AOD48, since the light emission angle can be changed by modulating the input acoustic frequency, the first processed light L1s can be spatially moved and scanned at high speed. That is, the AOD48 can deflect the first processed light L1s so that the first processed light L1s alternately scans the outer edges on both sides of the planned processing region R at timings shifted in time. AOD48 is an example of light deflection means.

In the laser processing method using the laser processing apparatus 10B of the third embodiment, when the direct condensing method processing is performed on the planned processing region R, the workpiece W is processed and fed in the X direction by the Xθ stage 14. However, while the AOD48 scans the first processed light L1s at a specific frequency at a high speed in the Y direction by a minute angle, the condenser lens 46 creates an interval (Y direction) according to the scanning angle (the above-mentioned minute angle). The first processed light L1s is condensed on the surface of the workpiece W (in a state where the distance between the two is large) (light deflection step). As a result, the condensing points of the first processed light L1s condensed by the condensing lens 46 alternately move at high speed on the outer edges on both sides of the planned processing region R, and the processing is performed by the direct condensing method.

Therefore, according to the third embodiment, since the first processing light L1s is spatially moved by the AOD48 and the direct condensing method processing is performed while scanning at high speed, both sides of the planned processing region R are processed in one pass. It is possible to perform direct light collecting method processing on the outer edge portion of the above, and the same effect as that of the first embodiment can be obtained.

In the third embodiment, a configuration including AOD48 is shown as an example of the optical deflection means, but the present invention is not limited to this, and for example, an optical scanning means such as a galvano scanner or a polygon scanner or another optical element is used. It may be configured.

(Fourth Embodiment)
Next, a fourth embodiment will be described.

FIG. 10 is a schematic view showing the laser processing apparatus 10C of the fourth embodiment. In FIG. 10, components common to or similar to those in FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted.

The fourth embodiment further includes a spatial light modulator 50 and a plurality of mirrors 52A to 52C in addition to the second embodiment.

As the spatial light modulator 50, for example, a spatial light modulator (SLM: Spatial Light Modulator) of a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) is used. The operation of the spatial light modulator 50 and the hologram pattern presented by the spatial light modulator 50 are controlled by the control unit 72. Since the specific configuration of the spatial light modulator 50 and the hologram pattern presented by the spatial light modulator 50 are already known, detailed description thereof will be omitted here.

The control unit 72 controls the operation of the spatial light modulator 50, and causes the spatial light modulator 50 to present a predetermined hologram pattern. Specifically, the first processing is performed so that the first processing light L1s is focused on the surface of the workpiece W by the condenser lens 46 at two different focusing points P1 and P2 (see FIG. 2). The spatial light modulator 50 is presented with a hologram pattern for modulating the light L1s. The hologram pattern is derived in advance based on the wavelength of the first processed light L1s, the condenser lens 46, and the like, and is stored in the control unit 72.

With this configuration, the first processed light L1s incident on the spatial light modulator 50 is modulated according to a predetermined hologram pattern presented on the spatial light modulator 50. At that time, in the control unit 72, the first processed light L1s differs from each other due to the condenser lens 46 inside the workpiece W (inside the surface film 22) located below the surface of the workpiece W. Control is performed so that the spatial light modulator 50 presents a hologram pattern for modulating the first processed light L1s so that the light is focused on the two focusing points P1 and P2.

The first processed light L1s emitted from the spatial light modulator 50 is sequentially reflected by the mirrors 52A to 52C, then passes through the dichroic mirror 38, and is incident on the condenser lens 46. Then, the first processed light L1s incident on the condenser lens 46 reaches two focusing points P1 and P2 in which the first processed light L1s is different from each other by the condenser lens 46 inside the surface film 22 by the condenser lens 46. It is focused.

In the laser processing method using the laser processing apparatus 10C of the fourth embodiment, the spatial light modulator 50 causes the first processed light L1s to move to each other inside the workpiece W (inside the surface film 22) by the condenser lens 46. Since the light is focused on two different light-collecting points P1 and P2, it is possible to perform direct light-condensing processing on the outer edges on both sides of the planned processing area R in one pass, which is the same as in the first embodiment. The effect can be obtained.

In each of the above-described embodiments, the Xθ stage 14 is provided so that the workpiece W can be moved in the X direction and can be rotated in the θ direction, and the machining unit 30 can be moved in the Y and Z directions. It suffices that the workpiece W and the machining unit 30 are configured to be relatively movable or rotatable in the X, Y, Z, and θ directions, and other embodiments different from the present embodiment may be appropriately used. Can be adopted.

Further, in each of the above-described embodiments, the configuration in which the direct condensing method processing and the liquid jet method processing are realized by one device is shown, but these processes may be realized by another device. In that case, as the laser light source used in the direct focusing method, it is also possible to use a picosecond or femtosecond laser having a shorter pulse width.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and it goes without saying that various improvements and modifications may be made without departing from the gist of the present invention. ..

10 ... Laser processing device, 12 ... Laser light source, 14 ... Xθ stage, 16 ... Liquid supply means, 20 ... Base layer, 21 ... Intermediate layer, 22 ... Surface film, 24a, 24b ... Modified layer, 26 ... Processing groove , 30 ... Processing unit, 32 ... Light amount adjusting means, 34 ... Polarized light adjusting means, 36 ... Polarized beam splitter, 38 ... Dycroic mirror, 40 ... Branch condensing means, 42 ... Mirror, 44 ... Beam shape shaping means, 46 ... Collection Optical lens, 48 ... AOD, 50 ... Spatial light modulator, 52 ... Mirror, 60 ... Processing head, 62 ... Condensing lens, 64 ... Transparent glass, 66 ... Liquid chamber, 68 ... Liquid jet injection nozzle, 70 ... AF device , 72 ... Control unit, L1 ... Laser light for processing, L1s ... First processing light, L1p ... Second processing light, L2 ... AF light, J ... Liquid jet

Claims (13)

Laser machining having a laser light source that emits a laser beam for machining, a machining unit that laser-machines a workpiece using the laser beam for machining, and a moving means that moves the machining unit and the workpiece relative to each other. It ’s a device,
The processing unit is
An optical branching means for branching the processing laser light emitted from the laser light source into a first laser light and a second laser light.
A second direction orthogonal to the first direction of the planned machining area along the first direction with respect to the workpiece that moves relative to the machining unit in the first direction by the moving means. A direct condensing means for forming a modified layer by condensing the first laser beam inside the surface film of the work piece at the outer edges on both sides of the above.
A pressurized liquid is injected by a liquid jet onto the workpiece that moves relative to the processing unit in the first direction by the moving means, and the liquid jet is used as a waveguide to use the liquid jet as a waveguide. A processing head that irradiates the inner region sandwiched between the outer edges on both sides of the planned processing region with the laser beam of 2.
Laser processing equipment equipped with. The direct condensing means has a branched condensing means for branching and condensing the first laser beam inside the surface film of the work piece at the outer edges on both sides of the planned processing region.
The laser processing apparatus according to claim 1. The branch condensing means can adjust the distance between the two condensing points of the first laser beam that has branched and condensated in the second direction according to the width of the planned processing region in the second direction. Consists of,
The laser processing apparatus according to claim 2. The branch condensing means comprises a spatial light modulator.
The laser processing apparatus according to claim 2. The direct condensing means said that the first laser beam alternately scans the inside of the surface film of the work piece at the outer edges on both sides of the planned processing region at time-shifted timings. It has a light deflecting means for deflecting the first laser beam.
The laser processing apparatus according to claim 1. The light deflection means comprises an acoustic optical element.
The laser processing apparatus according to claim 5. With respect to the workpiece that moves relative to the direct light collecting means in the first direction, the outer edges on both sides of the work schedule area along the first direction in the second direction orthogonal to the first direction. The first laser processing step of condensing the first laser light by the direct condensing means to form a modified layer inside the surface film of the work piece in the portion.
A second laser that injects a pressurized liquid from the machining head with a liquid jet and uses the liquid jet as a waveguide for the workpiece that moves relative to the machining head in the first direction. A second laser machining step of irradiating the inner region sandwiched between the outer edges on both sides of the planned machining region with light.
Laser processing method including. The process comprises an optical branching step of branching a processing laser beam emitted from a laser light source into the first laser beam and the second laser beam.
The laser processing method according to claim 7. The first laser processing step includes a branch focusing step of branching and condensing the first laser light inside the surface film of the workpiece at the outer edges on both sides of the planned processing region.
The laser processing method according to claim 8. The branch condensing step adjusts the distance between the two condensing points of the first laser beam branched and focused in the second direction according to the width of the planned processing region in the second direction. Has an adjustment process,
The laser processing method according to claim 9. In the branch focusing step, the first laser beam is branched and focused using a spatial light modulator.
The laser processing method according to claim 9. In the first laser machining step, the first laser beam alternately scans the inside of the surface film of the workpiece at the outer edges on both sides of the planned machining region at time-shifted timings. A light deflection step of deflecting the first laser beam.
The laser processing method according to claim 7. In the light deflection step, the first laser beam is deflected by using an acoustic optical element.
The laser processing method according to claim 12.