JP2022026680A - Laser processing device and laser processing method - Google Patents

Abstract

To provide a laser processing device and a laser processing method capable of laser processing with suppressed influence of variance in substrate thickness.SOLUTION: A laser processing device 1 irradiates an object 10 with laser light L to form a modified region in a functional element layer 12 provide on a top surface 11a side of a first substrate 11 of the object 10. The laser processing device 1 comprises a support part 2, a laser processing head 3, a focus position acquisition part 51, and a processing position setting part 52. The laser processing head 3 irradiates the object 10 with the laser light L and transmitted light L0 for observation from a reverse surface 11b side of the first substrate 11. The focus position acquisition part 51 acquires, as a metal layer focus position, a Z coordinate of the laser processing head 3 in a Z direction when the transmitted light L0 for observation is focused on a metal layer 12a. The processing position setting part 52 sets, as a laser processing position, the Z coordinate of the laser processing head 3 in the Z direction when the modified region is formed based upon the acquired metal layer focus position.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser processing apparatus and a laser processing method.

As a conventional laser processing apparatus, for example, Patent Document 1 describes an apparatus for forming a modified region inside an object to be machined. The laser processing apparatus described in Patent Document 1 illuminates the surface of the object to be processed, a mounting table on which the object to be processed is placed, an observation light source that emits illumination light, a laser light source that emits laser light, and the surface of the object to be processed. A condensing lens that condenses light and condenses laser light inside the object to be processed, and an imaging means that captures the reflected light of the illumination light condensed on the surface of the object to be processed and acquires imaging data. And prepare. In the laser processing apparatus described in Patent Document 1, after moving at least one of the mounting table and the condensing lens so that the focus of the illumination light is located on the surface of the object to be processed based on the imaging data, the laser is used. At least one of the mounting table and the condensing lens is moved in the thickness direction of the object to be processed so that the light condensing point is located inside the object to be processed.

Japanese Patent No. 5025776

In recent years, a laser processing apparatus has a substrate including a first main surface and a second main surface opposite to the first main surface, and a functional element layer provided on the first main surface side of the substrate and including a metal layer. The object may be irradiated with a laser beam for processing from the second main surface side to form a modified region inside the functional element layer along the virtual surface. In this case, when the modified region is formed by using the above-mentioned conventional technique, at least the mounting table and the condensing lens are formed in the thickness direction with respect to the laser light incident surface (second main surface) of the substrate. One is moved. Therefore, if the substrate thickness varies, the position of the condensing point of the laser beam (the position where the modified region is formed) in the thickness direction may vary due to the influence, and the processing quality may deteriorate.

Therefore, it is an object of the present invention to provide a laser processing apparatus and a laser processing method capable of laser processing while suppressing the influence of variations in substrate thickness.

The laser processing apparatus according to the present invention includes a substrate including a first main surface and a second main surface opposite to the first main surface, a functional element layer provided on the first main surface side of the substrate and including a metal layer, and a functional element layer. This is a laser processing device that irradiates an object with a laser beam for processing with a laser beam for processing to form a modified region inside the functional element layer along a virtual surface, and has a support portion that supports the object and processing. A processing irradiation unit that irradiates the object with laser light for observation from the second main surface side, an observation irradiation unit that irradiates the object with observation light transmitted through the substrate from the second main surface side, and a support unit. , A moving mechanism that moves at least one of the processing irradiation unit and the observation irradiation unit in the thickness direction of the object, and the observation irradiation unit in the thickness direction when the transmitted light for observation is focused on the metal layer. And / or in the thickness direction when forming the modified region with reference to the focal position acquisition unit that acquires the position of the support portion as the metal layer focal position and the metal layer focal position acquired by the focal position acquisition unit. It is provided with a processing position setting unit that sets the position of the irradiation unit and / or the support unit for processing as a laser processing position.

In this laser processing device, the focal position of the metal layer when the transmitted light for observation is focused on the metal layer instead of the incident surface of the laser light of the object is acquired, and the laser processing position is set based on the focal position of the metal layer. is doing. Therefore, even if the substrate becomes thicker or thinner, the laser processing position can be set without being affected by it. That is, it is possible to perform laser processing while suppressing the influence of variations in the substrate thickness.

Even if the laser processing apparatus according to the present invention has a first image pickup element that is sensitive to the transmitted light for observation and receives the reflected light reflected in response to the irradiation of the transmitted light for observation from the irradiation irradiation unit for observation. good. In this case, using the image pickup result of the first image pickup device, it is possible to move the observation irradiation portion and / or the support portion in the thickness direction so that the observation transmitted light is focused on the metal layer.

In the laser processing apparatus according to the present invention, the first image pickup element has further sensitivity to the processing laser light, and further receives the reflected light reflected in response to the irradiation of the processing laser light from the processing irradiation unit. May be good. In this case, for example, the beam shape of the laser beam for processing can be grasped by using the image pickup result of the first image pickup device.

The laser processing apparatus according to the present invention controls the moving mechanism based on the image pickup result of the first image pickup device, and has a thickness of the observation irradiation portion and / or the support portion so that the observation transmitted light is focused on the metal layer. It may be provided with an alignment portion for moving in a direction. In this case, the observation irradiation portion and / or the support portion can be automatically moved in the thickness direction so that the observation transmitted light is focused on the metal layer.

In the laser processing apparatus according to the present invention, the focal position of the metal layer is represented by the coordinates of the observation irradiation unit when the thickness direction is the coordinate axis on the support portion, and the laser processing position is the thickness direction on the support portion. May be represented by the coordinates of the processing irradiation unit when the coordinate axis is. As a result, the focal position of the metal layer and the laser processing position can be easily handled.

The laser processing apparatus according to the present invention includes a storage unit that stores a reference focal position which is a predetermined reference value of the metal layer focal position and a reference processing position which is a predetermined reference value of the laser processing position. The processing position setting unit may obtain the difference between the metal layer focal position acquired by the focal position acquisition unit and the reference focal position, and set the laser processing position based on the difference and the reference processing position. In this case, the laser machining position can be easily set.

In the laser machining apparatus according to the present invention, the machining position setting unit may set the laser machining position to a value obtained by adding or subtracting the reference machining position according to the difference or the correction value of the difference. In this case, the laser machining position can be set easily and accurately.

In the laser processing apparatus according to the present invention, the reference processing position is the median value of the processing margin range, and the processing margin range is such that the condensing point of the processing laser light moves in the thickness direction around the virtual surface. It may be the case where the irradiation portion for processing and / or the support portion is moved, and it may be within the range of the movement when the processing quality exceeds a certain level. In this case, if a low NA (numerical aperture) condensing portion of the laser beam for processing is used, a wider processing margin range can be obtained.

In the laser processing apparatus according to the present invention, the processing irradiation unit is positioned by a moving mechanism at the laser processing position set in the processing position setting unit, and the processing irradiation unit irradiates the object with the processing laser light. A laser machining execution unit that forms a modified region inside the functional element layer may be provided. In this case, the formation of the modified region inside the functional element layer can be concretely realized.

In the laser processing apparatus according to the present invention, the modified region may be formed so as to extend to a partial region or the entire region of the functional element layer when viewed from the thickness direction. In this case, the object can be peeled off by using the modified region formed in a part or all of the functional element layer when viewed from the thickness direction.

The laser processing apparatus according to the present invention includes a processing irradiation unit and a laser processing head constituting the observation irradiation unit, and the laser processing head may emit the processing laser light and the observation transmitted light coaxially. .. In this case, while the processing irradiation unit and the observation irradiation unit are integrally configured as a laser processing head, the processing laser light and the observation transmitted light can be coaxially emitted from the laser processing head.

The laser processing apparatus according to the present invention includes a processing irradiation unit and a laser processing head constituting the observation irradiation unit, and the laser processing head may emit the processing laser light and the observation transmitted light on different axes. good. In this case, while the processing irradiation unit and the observation irradiation unit are integrally configured as a laser processing head, the processing laser light and the observation transmitted light can be emitted from the laser processing head on different axes.

The laser processing apparatus according to the present invention may include a laser processing head that constitutes a processing irradiation unit and an observation head that constitutes an observation irradiation unit and is separate from the laser processing head. In this case, the processing laser light and the observation transmitted light are separated from the laser processing head and the observation head, respectively, while the processing irradiation unit and the observation irradiation unit are configured as a laser processing head and an observation head, respectively. It can be emitted by the axis.

Even if the laser processing apparatus according to the present invention is provided with a second image pickup element that is sensitive to the processing laser light and receives the reflected light reflected in response to the irradiation of the processing laser light from the processing irradiation unit. good. In this case, for example, the beam shape of the laser beam for processing can be grasped by using the image pickup result of the second image pickup element.

The laser processing method according to the present invention includes a substrate including a first main surface and a second main surface opposite to the first main surface, a functional element layer provided on the first main surface side of the substrate and including a metal layer, and a functional element layer. This is a laser processing method in which a modified region is formed along a virtual surface inside a functional element layer by irradiating an object having a target with a laser beam for processing, and the step is to support the object with a support portion. The step of irradiating the object with the processing laser light from the second main surface side by the processing irradiation unit, and the observation transmitted light transmitted through the substrate by the observation irradiation unit irradiating the object from the second main surface side. , The step of receiving the reflected light reflected by the irradiation of the transmitted transmitted light for observation by the first image pickup element, and the thickness of the object for the observation irradiation part and / or the support part based on the image pickup result of the first image pickup element. The step of acquiring the position of the observation irradiation portion and / or the support portion in the thickness direction when the observation transmitted light is focused on the metal layer by moving in the direction as the metal layer focal position, and the acquired metal layer focal point. A step of setting the position of the irradiation portion for processing and / or the support portion in the thickness direction when forming the modified region as the laser processing position with respect to the position is provided.

In this laser processing method, the focal position of the metal layer when the transmitted light for observation is focused on the metal layer instead of the incident surface of the laser beam of the object is acquired, and the laser processing position is set based on the focal position of the metal layer. is doing. Therefore, even if the substrate becomes thicker or thinner, the laser processing position can be set without being affected by it. That is, it is possible to perform laser processing while suppressing the influence of variations in the substrate thickness.

The laser processing method according to the present invention includes a reference value acquisition step for acquiring a reference focal position which is a reference value of the metal layer focal position and a reference processing position which is a reference value of the laser processing position, and is a reference value acquisition step. Then, in the step of supporting the object for reference setting by the support portion, the transmitted light for observation is irradiated to the object for reference setting from the second main surface side, and the reflected light is reflected according to the irradiation of the transmitted light for observation. When the light is received by the first image pickup element, the observation irradiation part and / or the support part is moved in the thickness direction based on the image pickup result of the first image pickup element, and the observation transmitted light is focused on the metal layer. The step of acquiring the position of the observation irradiation part and / or the support part in the thickness direction as the reference focal position, and the position of the processing irradiation part and / or the support part in the thickness direction are changed and the processing laser beam is used as a reference. The laser processing position includes a step of irradiating the object for setting from the second main surface side and acquiring a reference processing position based on the processing quality and the position of the processing irradiation portion and / or the support portion. In the step of setting, the difference between the acquired metal layer focal position and the reference focal position may be obtained, and the laser processing position may be set based on the difference and the reference processing position. In this case, the laser machining position can be easily set by using the reference focal position and the reference machining position.

According to the present invention, it is possible to provide a laser processing apparatus and a laser processing method capable of suppressing the influence of variations in substrate thickness.

FIG. 1 is a block diagram showing a laser processing apparatus of the first embodiment. FIG. 2 is a plan view and a cross-sectional view showing an object. FIG. 3 is an enlarged cross-sectional view showing a part of the object. FIG. 4 is a flowchart showing a reference value acquisition step. FIG. 5 is a flowchart showing the delamination process. FIG. 6A is a schematic cross-sectional view of an object for explaining the reference value acquisition step. FIG. 6 (b) is a diagram showing a continuation of FIG. 6 (a). FIG. 7 (a) is a diagram showing a continuation of FIG. 6 (b). FIG. 7 (b) is a diagram showing a continuation of FIG. 7 (a). FIG. 8A is a schematic cross-sectional view of an object for explaining delamination processing. FIG. 8 (b) is a diagram showing a continuation of FIG. 8 (a). FIG. 9A is a schematic cross-sectional view of an object for explaining general laser machining. FIG. 9B is a schematic cross-sectional view of an object for explaining general laser machining. FIG. 10 is a block diagram showing a laser processing apparatus according to a second embodiment. FIG. 11 is a block diagram showing a laser processing apparatus according to a third embodiment. FIG. 12 is a configuration diagram showing an observation head according to a modified example of the third embodiment. FIG. 13 is a block diagram showing the laser processing apparatus according to the fourth embodiment. FIG. 14 is an enlarged cross-sectional view showing a part of the object according to the modified example. FIG. 15A is a plan view and a cross-sectional view of an object for explaining a first example of forming a modified region in a part of a functional element layer. FIG. 15B is a plan view and a cross-sectional view of an object for explaining a second example of forming a modified region in a part of a functional element layer. FIG. 16A is a plan view and a cross-sectional view of an object for explaining a third example of forming a modified region in a part of a functional element layer. FIG. 16B is a plan view and a cross-sectional view of an object for explaining a fourth example of forming a modified region in a part of a functional element layer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

[First Embodiment]
The first embodiment will be described. The laser processing device 1 shown in FIG. 1 is a device that forms a modified region on the object 10 by irradiating the object 10 with laser light (laser light for processing) L. In the following description, the three directions orthogonal to each other are referred to as the X direction, the Y direction, and the Z direction, respectively. In the present embodiment, the X direction is the first horizontal direction, the Y direction is the second horizontal direction perpendicular to the first horizontal direction, and the Z direction is the vertical direction. The Z direction corresponds to the thickness direction of the object 10.

As shown in FIGS. 2 and 3, the object 10 has a first substrate 11, a functional element layer 12, and a second substrate 13. The first substrate 11, the functional element layer 12, and the second substrate 13 are arranged so as to be laminated in this order in the Z direction.

The first substrate 11 and the second substrate 13 are wafers formed in a disk shape. The first substrate 11 and the second substrate 13 are, for example, a semiconductor substrate such as a silicon substrate, a piezoelectric material substrate made of a piezoelectric material, a glass substrate made of glass, and the like. The first substrate 11 and the second substrate 13 may be provided with a notch or an orientation flat indicating the crystal orientation. The first substrate 11 includes a front surface (first main surface) 11a and a back surface (second main surface) 11b opposite to the front surface 11a. The second substrate 13 includes a front surface 13a and a back surface 13b opposite to the front surface 13a. Here, the first substrate 11 and the second substrate 13 are arranged so that the surfaces 11a and 13a face each other.

The functional element layer 12 is provided on the surface 11a side of the first substrate 11. The functional element layer 12 is provided on the surface 13a side of the second substrate 13. The functional element layer 12 includes a plurality of functional elements. Each functional element is, for example, a wiring element, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, or the like. Each functional element may be configured three-dimensionally by stacking a plurality of layers, or may be arranged in a matrix. The functional element layer 12 here includes a plurality of metal layers 12a and a plurality of non-metal layers 12b, and these are laminated in the Z direction.

The metal layer 12a includes a Ti (titanium) layer, a Sn (tin) layer and the like. The non-metal layer 12b includes, for example, an oxide film layer and a nitride film layer. The non-metal layer 12b includes, for example, a SiO (silicon monoxide) layer and a SiCn (silicon carbon nitride) layer. The metal layer 12a and the non-metal layer 12b are formed on the surfaces 11a and 13a by, for example, a film forming process (sputtering, vapor deposition, CVD, etc.), an etching process (dry etching or wet etching), a polishing process, or the like.

A virtual surface M1 as a planned peeling surface is set on the object 10. The virtual surface M1 is a surface on which a modified region is planned to be formed. The virtual surface M1 is a surface facing the back surface 11b, which is the laser beam incident surface of the object 10. The virtual surface M1 is a surface parallel to the back surface 11b, and has a circular shape, for example. The virtual surface M1 is a virtual area, and is not limited to a plane, but may be a curved surface or a three-dimensional surface. The setting of the virtual surface M1 can be performed by the user via an operation input unit (not shown). The virtual surface M1 may have coordinates specified.

As shown in FIG. 1, the laser processing apparatus 1 of the present embodiment aligns a condensing point (at least a part of a condensing region) with an object 10 and irradiates the object 10 with a laser beam L. A modified region is formed inside the functional element layer 12 along the virtual surface M1 (see FIG. 2). The laser processing apparatus 1 performs laser processing including peeling processing on the object 10. The peeling process is a process for peeling a part of the object 10. The laser processing device 1 has a function as a laser debonding device. The position of the virtual surface M1 (that is, the position where the modified region is formed) is a position in the functional element layer 12 that does not include the metal layer 12a (that is, contains only the non-metal layer 12b) on the laser beam incident side. ..

The laser processing device 1 includes a support unit 2, a laser processing head 3, a moving mechanism 4, a control unit 5, and a display unit 6. The support portion 2 supports the object 10 by, for example, adsorption. The support portion 2 can move along each of the X direction, the Y direction, and the Z direction. The object 10 is placed on the support portion 2 of the present embodiment with the back surface 11b on the upper side, which is the laser beam incident surface side. The support portion 2 has a rotation axis extending along the Z direction, and is rotatable about this rotation axis.

The laser processing head 3 includes a processing light source 31, an observation light source 32, a condensing unit 33, and a first image pickup element 34. The processing light source 31 emits a processing laser beam L by, for example, a pulse oscillation method. The laser beam L is a laser beam in a wavelength range having absorbency in the functional element layer 12. For example, as the processing light source 31, a solid-state pulse laser device is used, and the wavelength of the laser beam L is 355 nm. The observation light source 32 emits the observation transmitted light L0 transmitted through the first substrate 11. The transmitted light L0 for observation is light in a wavelength range having transparency to the first substrate 11. The observation light source 32 is not particularly limited, and various light sources can be used as long as the transmitted transmitted light L0 for observation can be emitted.

The condensing unit 33 condenses the laser light L and the transmitted light L0 for observation on the object 10 supported by the support unit 2. In the present embodiment, the laser beam L emitted from the processing light source 31 is reflected by the dichroic mirror H1 and is incident on the light collecting unit 33. Further, the transmitted light L0 for observation emitted from the light source 32 for observation is reflected by the dichroic mirror H2, passes through the dichroic mirror H1, and is incident on the condensing unit 33. The condensing unit 33 condenses the laser light L and the transmitted light L0 for observation so incident on the object 10. The light collecting unit 33 is configured to include, for example, a lens unit composed of a plurality of light collecting lenses. As the lens unit of the condensing unit 33, a lens unit having a low NA (numerical aperture) can be used. The light collecting unit 33 may or may not have a driving mechanism such as a piezoelectric element that drives the lens unit in the Z direction. Examples of the low NA include 0.1 to 0.4.

The first image pickup device 34 is an image pickup device having sensitivity to the transmitted light L0 for observation. The first image pickup element 34 receives the reflected light reflected in response to the irradiation of the transmitted transmitted light L0 for observation (condensing the transmitted transmitted light L0 for observation on the object 10 by the condensing unit 33). In the present embodiment, the reflected light of the observation transmitted light L0, which is irradiated on the object 10 and reflected by the metal layer 12a of the functional element layer 12, is first imaged through the condensing unit 33 and the dichroic mirrors H1 and H2. It is detected by the element 34. For example, the first image pickup device 34 acquires an image of the metal layer 12a by the transmitted light L0 for observation as an image.

Further, the first image sensor 34 has further sensitivity to the laser beam L. The first image pickup element 34 further receives the reflected light reflected by the irradiation of the laser beam L (condensing the laser beam L on the object 10 by the condensing unit 33). In the present embodiment, the reflected light of the laser beam L irradiated and reflected on the object 10 is detected by the first image sensor 34 via the condensing unit 33 and the dichroic mirrors H1 and H2. For example, the first image sensor 34 acquires an image related to the beam shape of the laser beam L as an image. The first image sensor 34 outputs the image pickup result to the control unit 5.

Such a laser processing head 3 coaxially emits the laser beam L and the transmitted light L0 for observation. The laser processing head 3 constitutes a processing irradiation unit that irradiates the object 10 with the laser beam L from the back surface 11b side and an observation irradiation unit that irradiates the object 10 with the observation transmitted light L0 from the back surface 11b. The laser processing head 3 may or may not be provided with a spatial light modulator that modulates the laser beam L.

The moving mechanism 4 includes a mechanism for moving at least one of the support portion 2 and the laser machining head 3 in the X direction, the Y direction, and the Z direction. The moving mechanism 4 has at least one of the support portion 2 and the laser processing head 3 by the driving force of a known driving device such as a motor so that the condensing point of the laser beam L moves in the X direction, the Y direction, and the Z direction. To drive. The moving mechanism 4 drives at least one of the support portion 2 and the laser machining head 3 by the driving force of a known driving device such as a motor so that the focal point of the transmitted light L0 for observation moves in the Z direction. Further, the moving mechanism 4 includes a mechanism for rotating the support portion 2 about the rotation axis. The moving mechanism 4 rotationally drives the support portion 2 by the driving force of a known driving device such as a motor so that the condensing point of the laser beam L moves in the θ direction around the rotation axis. The moving mechanism 4 is not particularly limited, and various known mechanisms can be adopted.

The control unit 5 controls the operation of each unit of the laser processing apparatus 1. The control unit 5 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 5, the processor executes software (program) read into the memory or the like, and controls reading and writing of data in the memory and storage, and communication by the communication device. The control unit 5 includes a focal position acquisition unit 51, a processing position setting unit 52, a storage unit 53, and a laser processing execution unit 54.

The focal position acquisition unit 51 sets the position of the laser processing head 3 in the Z direction when the observed transmitted light L0 is in focus on the metal layer 12a as the metal layer focal position (hereinafter, simply referred to as “metal layer focal position”). get. The focal position of the metal layer is represented by the Z coordinate (coordinate of the coordinate axis in the Z direction) of the laser processing head 3 on the support portion 2. For example, when the image of the metal layer 12a by the observation transmitted light L0 displayed on the display unit 6 is in focus on the metal layer 12a, the position in the Z direction of the laser processing head 3 at that time is the focus position acquisition unit 51. Is acquired as the focal position of the metal layer.

The processing position setting unit 52 sets the position of the laser processing head 3 in the Z direction when forming a modified region by condensing the laser beam L with reference to the metal layer focal position acquired by the focal position acquisition unit 51. It is set as a laser processing position (hereinafter, simply referred to as "laser processing position"). The laser machining position is represented by the Z coordinate of the laser machining head 3 on the support portion 2. Specifically, the processing position setting unit 52 obtains the difference between the metal layer focal position acquired by the focal position acquisition unit 51 and the reference focal position stored in the storage unit 53. Then, the machining position setting unit 52 sets the laser machining position based on the obtained difference and the reference machining position stored in the storage unit 53. As an example, the machining position setting unit 52 sets the Z coordinate obtained by adding or subtracting the reference machining position according to the correction value of the difference as the laser machining position.

The storage unit 53 is, for example, a hard disk or the like, and stores various data. The storage unit 53 stores a reference focal position, which is a predetermined reference value for the metal layer focal position, and a reference machining position, which is a predetermined reference value for the laser machining position. The reference machining position is the margin center, which is the median value of the machining margin range. The processing margin range is a case where the laser processing head 3 and / or the support portion 2 is moved so that the condensing point of the laser beam L moves in the Z direction around the virtual surface M1, and the processing quality is equal to or higher than a certain level. It is the range of the movement when it becomes (details will be described later). The machining margin range is also referred to as the machining process window.

The laser processing execution unit 54 positions the laser processing head 3 by the moving mechanism 4 at the laser processing position set by the processing position setting unit 52, and emits the laser light L from the laser processing head 3 so as to concentrate on the functional element layer 12. The object 10 is irradiated. When the laser beam L is focused inside the functional element layer 12, the laser beam L is absorbed at the portion corresponding to the focusing point of the laser beam L, and a modified region is formed. The modified region is a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding non-modified region. The modified region includes, for example, a melt processing region, a crack region, a dielectric breakdown region, a refractive index change region, and the like. The modified region contains a plurality of modified spots and cracks extending from the plurality of modified spots.

The laser processing execution unit 54 is subjected to the support unit 2 and the laser processing by the moving mechanism 4 so that the condensing point of the laser light L moves along the virtual surface M1 in accordance with the irradiation of the laser light L from the laser processing head 3. Move at least one of the heads 3. For example, the laser machining execution unit 54 controls the movement of the laser machining head 3 in the X direction and / or the Y direction while rotating the support portion 2.

The display unit 6 is, for example, a monitor or the like. The display unit 6 is controlled by the control unit 5 and displays the image pickup result of the first image pickup element 34. The display unit 6 displays an image of the metal layer 12a by the transmitted light L0 for observation. By confirming whether or not the metal layer 12a displayed on the display unit 6 is in focus, it is possible to confirm whether or not the observation transmitted light L0 is in focus on the metal layer 12a. The display unit 6 displays an image of the beam shape of the laser beam L. By confirming whether or not the beam shape displayed on the display unit 6 is the narrowest, the position of the condensing point of the laser beam L can be confirmed. The display unit 6 is not particularly limited, and various known display devices can be used.

Next, a laser processing method using the laser processing device 1 will be described. Here, an example of delamination processing in which the object 10 is separated by the functional element layer 12 using the laser processing device 1 will be described.

In the laser processing method of the present embodiment, the object 10 is irradiated with the laser beam L, and a modified region is formed inside the functional element layer 12 along the virtual surface M1. In the laser processing method of the present embodiment, first, prior to performing delamination processing on the object 10B for production, a reference value acquisition step for acquiring a reference focal position and a reference processing position is performed as a pre-processing step.

In the reference value acquisition step, as shown in FIG. 4, the reference setting object 10 is attached to the support portion 2, and the reference setting object 10A is supported on the support portion 2 (step S1). In step S1, the object 10A is placed on the support portion 2 with the back surface 11b of the first substrate 11 facing the laser beam incident surface side.

Acquire the reference focal position (step S2). In step S2, the laser processing head 3 irradiates the object 10A with the transmitted light L0 for observation from the back surface 11b side, and the first image sensor 34 receives the reflected light reflected in response to the irradiation of the transmitted light L0 for observation. See FIG. 6 (a)). The image (imaging result) of the metal layer 12a imaged by the first image sensor 34 is displayed on the display unit 6. The laser processing head 3 is moved in the Z direction by the moving mechanism 4, and the laser processing head when the metal layer 12a displayed on the display unit 6 is in focus, that is, the metal layer 12a is in focus of the transmitted light L0 for observation. The Z coordinate of 3 is acquired as a reference focal position. The acquired reference focal position is stored in the storage unit 53.

Acquire the machining margin range (step S3). In step S3, for example, the laser processing head 3 is moved in the Z direction by the moving mechanism 4 so that the condensing point of the laser beam L is located on the virtual surface M1 (see FIG. 6B). After that, the Z coordinate of the laser processing head 3 is changed, the laser beam L is irradiated to the object 10A from the back surface 11b side, and this is repeated a plurality of times. The machining margin range is acquired based on the machining quality at this time and the Z coordinate of the laser machining head 3. For example, in laser machining in which the Z coordinate of the laser machining head 3 is gradually increased or decreased from the position of the virtual surface M1, a set of Z coordinates of the laser machining head 3 when the machining quality becomes a certain level or higher is machined. Obtained as a margin range KM (see FIGS. 7 (a) and 7 (b)). The processing quality above a certain level is synonymous with the case where the processing quality is not affected. The processing quality can be grasped from the image by displaying the image of the functional element layer 12 imaged by the first image pickup element 34 during or after the laser processing on the display unit 6.

The margin center, which is the median value of the machining margin range KM, is acquired as a reference machining position and stored in the storage unit 53 (step S4). The object 10A is removed from the support portion 2, and the reference value acquisition step is completed (step S5).

Incidentally, in step S3, the positional relationship between the Z coordinate of the laser processing head 3 and the condensing point of the laser beam L is stored in the storage unit 53 in advance, and the laser processing head 3 is moved in the Z direction based on this positional relationship. You may move it. The positional relationship between the Z coordinate of the laser processing head 3 and the condensing point of the laser beam L may be stored in advance in the storage unit 53 as follows, for example. That is, an image of the beam shape of the laser beam L on the back surface 11b is imaged by the first image sensor 34 and displayed on the display unit 6. The laser processing head 3 is moved in the Z direction by the moving mechanism 4 so that the beam shape becomes the smallest (the beam diameter is minimized). The positional relationship between the Z coordinate of the laser processing head 3 and the back surface 11b at this time may be stored in advance in the storage unit 53 as the positional relationship between the Z coordinate of the laser processing head 3 and the condensing point of the laser beam L.

Subsequently, the delamination process shown in FIG. 5 is performed. In the delamination process, the object 10B for production is attached to the support portion 2, and the object 10B is supported on the support portion 2 (step S11). In step S11, the object 10B is placed on the support portion 2 with the back surface 11b of the first substrate 11 facing the laser beam incident surface side.

Acquire the focal position of the metal layer (step S12). In step S12, the laser processing head 3 irradiates the object 10B with the transmitted light L0 for observation from the back surface 11b side, and the first image sensor 34 receives the reflected light reflected in response to the irradiation of the transmitted light L0 for observation. See FIG. 8 (a)). The image (imaging result) of the metal layer 12a imaged by the first image sensor 34 is displayed on the display unit 6. The laser processing head 3 is moved in the Z direction by the moving mechanism 4, and the laser processing head when the metal layer 12a displayed on the display unit 6 is in focus, that is, the metal layer 12a is in focus of the transmitted light L0 for observation. The Z coordinate of 3 is acquired as the focal position of the metal layer. The acquired metal layer focal position is stored in the storage unit 53.

The laser processing position is set with reference to the acquired metal layer focal position. That is, for example, according to the following equation (1), the difference between the metal layer focal position acquired in step S12 and the reference focal position stored in the storage unit is obtained (step S13). Then, for example, according to the following equation (2), the laser machining position is set based on the difference and the reference machining position (step S14). α and β are correction coefficients when correction is necessary. When no correction is required, α = 1 and β = 0. α and β can be predetermined based on known techniques from at least one of experimental, empirical, and theoretical viewpoints.
Difference = metal layer focal position-reference focal position ... (1)
Laser machining position = reference machining position + (α x difference + β) ... (2)

Laser processing is performed (step S15). In step S15, the laser processing head 3 irradiates the object 10B with the laser beam L from the back surface 11b side of the first substrate 11 (see FIG. 8B). The laser machining head 3 is moved in the Z direction by the moving mechanism 4 so that the laser machining head 3 is positioned at the set laser machining position. In this state, the laser processing head 3 irradiates the object 10B with the laser beam L from the back surface 11b side of the first substrate 11, and the laser beam L is condensed on the functional element layer 12. Along with the irradiation of the laser beam L from the laser machining head 3, the movement of the laser machining head 3 in the X direction and / or the Y direction is controlled while rotating the support portion 2, and the condensing point of the laser beam L is set as a virtual surface. Move along M1. As a result, a modified region is formed inside the functional element layer 12 along the virtual surface M1. Here, the modified region is formed so as to extend over the entire region of the functional element layer 12 when viewed from the Z direction.

After that, the object 10B is removed from the support portion 2 (step S16). After that, the delamination processing is performed on the second and subsequent objects 10B in the same manner as in steps S11 to S16, or the delamination processing is completed.

By the way, in general laser processing, for example, as shown in FIG. 9A, when a modified region is formed on an object 10, an illumination light L1 is formed on a back surface 11b which is a laser light incident surface of the first substrate 11. The laser processing head 3 is moved by a predetermined amount H in the Z direction with reference to the Z coordinate of the laser processing head 3 (condensing unit 33) when the focal point of the laser processing head 3 is located. Therefore, for example, as shown in FIG. 9B, when the thickness of the first substrate 11 varies (it becomes thicker in the drawing), the position of the condensing point of the laser beam L in the Z direction is changed due to the influence. There is a possibility that the formation position of the quality region will vary and the processing quality will deteriorate.

In this regard, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the metal layer focal position when the observation transmitted light L0 is focused on the metal layer 12a instead of the back surface 11b of the first substrate 11 is acquired. The laser processing position is set with reference to the focal position of this metal layer. Therefore, even if the first substrate 11 becomes thicker or thinner, the laser processing position can be set without being affected by the thickness. Further, even if the second substrate 13 becomes thicker or thinner, the laser processing position can be set without being affected by the thickness. It is not necessary to grasp the thicknesses of the first and second substrates 11 and 13. That is, it is possible to perform laser processing while suppressing the influence of variations in the substrate thicknesses of the first and second substrates 11 and 13.

The present embodiment includes a first image sensor 34. The first image sensor 34 has sensitivity to the transmitted transmitted light L0 for observation, and receives the reflected light of the transmitted transmitted light L0 for observation. In this case, the laser processing head 3 can be moved in the Z direction so that the transmitted light L0 for observation is in focus on the metal layer 12a by using the image pickup result of the first image pickup element 34.

In the present embodiment, the first image sensor 34 has further sensitivity to the laser beam L and further receives the reflected light of the laser beam L. In this case, the beam shape of the laser beam L can be grasped as described above by using the image pickup result of the first image pickup element 34.

In the present embodiment, the metal layer focal position and the laser processing position are represented by Z coordinates. As a result, the focal position of the metal layer and the laser processing position can be easily handled.

In the present embodiment, the reference focal position and the reference machining position are stored, the difference between the metal layer focal position and the reference focal position is obtained, and the laser machining position is set based on the difference and the reference machining position. In this case, the laser machining position can be easily set. By using the low NA condensing unit 33 for condensing the transmitted light L0 for observation and the laser light L, the influence of aberration due to the transmission between the first substrate 11 and the non-metal layer 12b is reduced, and this setting is made. The method can be used.

In the present embodiment, the laser machining position is set to a value obtained by adjusting the reference machining position according to the correction value of the difference between the metal layer focal position and the reference focal position. In this case, the laser machining position can be set easily and accurately.

In the present embodiment, the reference machining position is the median value of the machining margin range KM. In this case, by using the low NA condensing unit 33 as the condensing unit of the laser beam L, the condensing point size becomes large at the low NA, so that a wider processing margin range KM can be obtained.

In the present embodiment, the laser machining head 3 is positioned by the moving mechanism 4 at the laser machining position set by the machining position setting unit 52, and the laser machining head 3 irradiates the object 10 with the laser beam L to irradiate the object 10 with the laser beam L. A modified region is formed inside the twelve. Thereby, the formation of the modified region along the virtual surface M1 inside the functional element layer 12 can be concretely realized.

In the present embodiment, the modified region is formed so as to extend over the entire region of the functional element layer 12 when viewed from the Z direction. In this case, the object 10 can be delaminated by utilizing the modified region formed in a part or the whole region of the functional element layer 12.

The laser processing apparatus 1 of the present embodiment includes a laser processing head 3, and the laser light L and the transmitted light L0 for observation are coaxially emitted from the laser processing head 3. In this case, the laser light L and the transmitted light L0 for observation can be emitted coaxially while the processing irradiation unit and the observation irradiation unit are integrally configured as the laser processing head 3. It is possible to simplify the device configuration.

The laser machining method of the present embodiment includes a reference value acquisition step for acquiring a reference focal position and a reference machining position. In the reference value acquisition step, the object 10A for setting the reference is supported, the transmitted light L0 for observation is irradiated to the object 10A from the back surface 11b, the reflected light is received by the first image sensor 34, and the first image sensor is used. Based on the image pickup result of 34, the laser processing head 3 is moved in the Z direction to acquire a reference focal position. The position of the laser processing head 3 in the Z direction is changed, the laser beam L is irradiated to the object 10A from the back surface 11b side, and the reference processing position is acquired based on the processing quality and the Z coordinate of the laser processing head 3. After that, when setting the laser processing position, the difference between the metal layer focal position and the reference focal position is obtained, and the laser processing position is set based on the difference and the reference processing position. As a result, the laser machining position can be easily set by using the reference focal position and the reference machining position.

[Second Embodiment]
The second embodiment will be described. In the description of the second embodiment, the differences from the first embodiment will be described, and duplicate description will be omitted.

As shown in FIG. 10, the laser processing apparatus 101 according to the second embodiment is different from the first embodiment in that the laser processing head 3 further includes the second image pickup element 35. The second image pickup device 35 has further sensitivity to the laser beam L, and further receives the reflected light reflected in response to the irradiation of the laser beam L. In the present embodiment, the reflected light of the laser beam L irradiated and reflected on the object 10 is detected by the second image sensor 35 via the condensing unit 33 and the dichroic mirrors H1, H2, and H3. For example, the second image sensor 35 acquires an image related to the beam shape of the laser beam L as an image. The second image sensor 35 outputs the image pickup result to the control unit 5. The first image sensor 34 of the present embodiment does not have to have sensitivity to the laser beam L. The display unit 6 may further display the image pickup result of the second image pickup element 35.

As described above, also in the laser processing apparatus 101 and the laser processing method according to the present embodiment, it is possible to perform laser processing while suppressing the influence of the variation in the substrate thickness of the first and second substrates 11 and 13. Further, since the laser processing device 101 includes the second image pickup element 35, it is possible to grasp the beam shape and the like of the laser beam L by using the image pickup result of the second image pickup element 35.

[Third Embodiment]
The third embodiment will be described. In the description of the third embodiment, the differences from the first embodiment will be described, and duplicate description will be omitted.

As shown in FIG. 11, the laser machining apparatus 201 according to the third embodiment includes the laser machining head 3A and the observation head 3B in place of the laser machining head 3 (see FIG. 1). Is different.

The laser processing head 3A includes a processing light source 31, a condensing unit 33A, and a second image pickup element 35. The light collecting unit 33A concentrates the laser beam L on the object 10 supported by the support unit 2. In the present embodiment, the laser beam L emitted from the processing light source 31 is reflected by the dichroic mirror H1 and is incident on the light collecting unit 33A. The condensing unit 33A condenses the laser beam L so incident on the object 10. The light collecting unit 33A is configured to include, for example, a lens unit composed of a plurality of light collecting lenses. As the lens unit of the condensing unit 33A, a lens unit having a low NA can be used. The second image pickup device 35 has further sensitivity to the laser beam L, and further receives the reflected light reflected in response to the irradiation of the laser beam L. For example, the second image sensor 35 acquires an image related to the beam shape of the laser beam L as an image. The second image sensor 35 outputs the image pickup result to the control unit 5.

The observation head 3B includes an observation light source 32, a condensing unit 33B, and a first image pickup element 34. The light collecting unit 33B collects the transmitted light L0 for observation on the object 10 supported by the support unit 2. In the present embodiment, the transmitted light L0 for observation emitted from the light source 32 for observation is reflected by the dichroic mirror H2 and is incident on the condensing unit 33B. The condensing unit 33B condenses the observation transmitted light L0 so incident on the object 10. Similar to the condensing unit 33A, the condensing unit 33B includes, for example, a lens unit composed of a plurality of condensing lenses.

As described above, the laser processing head 3A and the observation head 3B are configured as separate bodies from each other, and emit the laser light L and the observation transmitted light L0, respectively. The laser processing head 3A constitutes a processing irradiation unit that irradiates the object 10 with the laser beam L from the back surface 11b side, and the observation head 3B irradiates the object 10 with the transmitted light L0 for observation from the back surface 11b. It constitutes an irradiation unit. The laser processing head 3A may or may not be provided with a spatial light modulator that modulates the laser beam L.

In the moving mechanism 4 of the present embodiment, the laser machining head 3A and the observation head 3B may be independently movable in the Z direction, or the laser machining head 3A and the observation head 3B may be integrally moved in the Z direction. It may be movable.

As described above, also in the laser processing apparatus 201 and the laser processing method according to the present embodiment, it is possible to perform laser processing while suppressing the influence of the variation in the substrate thickness of the first and second substrates 11 and 13. Further, while the processing irradiation unit and the observation irradiation unit are separately configured as the laser processing head 3A and the observation head 3B, respectively, the laser light L and the observation transmitted light L0 are each of the laser processing head 3A and the observation head. It can be emitted from each of 3B on a different axis.

FIG. 12 is a configuration diagram showing an observation head 3B according to a modified example of the third embodiment. As shown in FIG. 12, the observation head 3B may have a plurality of condensing units 33B and a plurality of first image pickup elements 34. The magnification of each lens unit included in the plurality of condensing units 33B may be different from each other. In this case, the light transmitting light L0 for observation may be focused on the object 10 by using the light collecting unit 33B including the lens unit having the highest magnification among the plurality of light collecting units 33B.

[Fourth Embodiment]
The fourth embodiment will be described. In the description of the fourth embodiment, the differences from the first embodiment will be described, and duplicate description will be omitted.

As shown in FIG. 13, the laser machining apparatus 301 according to the fourth embodiment is different from the first embodiment in that the laser machining head 303 is provided in place of the laser machining head 3 (see FIG. 1).

The laser processing head 303 includes a processing light source 31, a condensing unit 333A, a first image pickup element 34, an observation light source 32, a condensing unit 333B, and a second image pickup element 35. The light collecting unit 333A collects the laser beam L on the object 10 supported by the support unit 2. In the present embodiment, the laser beam L emitted from the processing light source 31 is reflected by the dichroic mirror H1 and is incident on the light collecting unit 333A. The condensing unit 333A condenses the laser beam L so incident on the object 10. The light collecting unit 333A is configured to include, for example, a lens unit composed of a plurality of light collecting lenses. As the lens unit of the condensing unit 333A, a lens unit having a low NA can be used.

The light collecting unit 333B collects the transmitted light L0 for observation on the object 10 supported by the support unit 2. In the present embodiment, the transmitted light L0 for observation emitted from the light source 32 for observation is reflected by the dichroic mirror H2 and is incident on the condensing unit 333B. The condensing unit 333B condenses the observation transmitted light L0 so incident on the object 10. Similar to the condensing unit 333A, the condensing unit 33B includes, for example, a lens unit composed of a plurality of condensing lenses. The second image pickup device 35 has further sensitivity to the laser beam L, and further receives the reflected light reflected in response to the irradiation of the laser beam L. For example, the second image sensor 35 acquires an image related to the beam shape of the laser beam L as an image. The second image sensor 35 outputs the image pickup result to the control unit 5.

Such a laser processing head 303 emits the laser beam L and the transmitted light L0 for observation on different axes. The laser processing head 303 constitutes a processing irradiation unit that irradiates the object 10 with the laser beam L from the back surface 11b side and an observation irradiation unit that irradiates the object 10 with the observation transmitted light L0 from the back surface 11b. The laser processing head 303 may or may not be provided with a spatial light modulator that modulates the laser beam L.

As described above, also in the laser processing apparatus 301 and the laser processing method according to the present embodiment, it is possible to perform laser processing while suppressing the influence of the variation in the substrate thickness of the first and second substrates 11 and 13. Further, while the processing irradiation unit and the observation irradiation unit are integrally configured as the laser processing head 303, the laser light L and the observation transmitted light L0 can be emitted from the laser processing head 303 on different axes.

[Modification example]
One aspect of the present invention is not limited to the above-described embodiment.

In the above embodiment, the object 10 has the first substrate 11 and the second substrate 13, but is not limited thereto. The object 10 does not have to have the second substrate 13, for example, as shown in FIG. In the above embodiment, the laser processing position is corrected by using the correction coefficients α and β, but the correction may not be performed. In the above embodiment, the laser machining position is corrected by using a linear function as exemplified by the above equation (2), but the laser machining position is corrected by using an nth-order function (n is an integer of 2 or more). It may be corrected. The first image sensor 34 of the above embodiment does not have to have sensitivity to the laser beam L.

In the above embodiment, the control unit 5 controls the moving mechanism 4 based on the image pickup result of the first image pickup element 34, and the laser processing heads 3, 3A, so that the metal layer 12a is in focus of the transmitted light L0 for observation. An alignment portion for moving the 303 and the observation head 3B in the Z direction may be provided. In this case, the laser processing heads 3, 3A, 303 and the observation head 3B can be automatically moved in the Z direction so that the observation transmitted light L0 is in focus on the metal layer 12a.

In the above embodiment, the laser machining heads 3, 3A, 303 and the observation head 3B are moved in the Z direction by the moving mechanism 4, but instead of or in addition to this, the support portion 2 is moved in the Z direction by the moving mechanism 4. You may move it. In the above embodiment, the condensing unit 33, 33A, 33B, 333A, 333B may include, for example, a single lens instead of the lens unit.

In the above embodiment, the virtual surface M1 extending over the entire region of the functional element layer 12 is set when viewed from the Z direction, and the modified region is formed so as to extend over the entire region of the functional element layer 12 (whole surface delamination processing). However, it is not limited to this. When viewed from the Z direction, a virtual surface extending over a part of the functional element layer 12 may be set, and the modified region may be formed so as to spread over a part of the functional element layer 12. In this case, the object 10 can be delaminated by utilizing the modified region formed in a part of the functional element layer 12.

For example, as shown in FIG. 15A, a virtual surface M2 extending over the outer peripheral portion of the functional element layer 12 is set when viewed from the Z direction, and the modified region is formed so as to extend over the outer peripheral portion of the functional element layer 12. It may be (peripheral delamination processing). Further, for example, as shown in FIG. 15B, a virtual surface M3 extending to the inner peripheral portion of the functional element layer 12 is set when viewed from the Z direction, and the modified region is expanded to the inner peripheral portion of the functional element layer 12. It may be formed as follows (inner peripheral delamination processing).

Further, for example, as shown in FIG. 16A, the arcuate virtual surface M4 may be set when viewed from the Z direction, and the modified region may be formed so as to extend to a part of the arcuate portion in the functional element layer 12 (. Partial delamination processing). Further, for example, as shown in FIG. 16 (b), a virtual surface M5 is set to spread over a part of a circle sandwiched between a pair of bows when viewed from the Z direction, and the modified region is the part of the functional element layer 12. It may be formed so as to spread to (partial delamination processing).

In the above embodiment, the type of the object 10, the shape of the object 10, the size of the object 10, the number and directions of crystal orientations of the object 10, and the plane orientation of the main surface of the object 10 are not particularly limited. .. In the above embodiment, the object 10 may be formed by including a crystalline material having a crystalline structure, or in place of or in addition to the crystalline material having a non-crystalline structure (amorphous structure). It may be formed by including. The crystal material may be either an anisotropic crystal or an isotropic crystal. For example, the object 10 includes gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO ₃ , diamond, GaOx, sapphire ( _{Al2O 3 )} , gallium arsenide, indium phosphide, glass, and alkali-free. It may include a substrate formed of at least one of glass.

In the above embodiment, the modified region may be, for example, a crystal region, a recrystallization region, or a gettering region formed inside the object 10. The crystal region is a region that maintains the structure of the object 10 before processing. The recrystallized region is a region that once evaporates, becomes plasma, or melts, and then solidifies as a single crystal or polycrystal when resolidified. The gettering region is a region that exerts a gettering effect of collecting and capturing impurities such as heavy metals, and may be formed continuously or intermittently. The above embodiment may be applied to processing such as ablation.

Various materials and shapes can be applied to the configurations in the above-described embodiments and modifications, without being limited to the above-mentioned materials and shapes. Further, each configuration in the above-described embodiment or modification can be arbitrarily applied to each configuration in another embodiment or modification.

1,101,201,301 ... Laser processing device, 2 ... Support part, 3,303 ... Laser processing head (processing irradiation part, observation irradiation part), 3A ... Laser processing head (processing irradiation part), 3B ... Observation head (observation irradiation unit), 4 ... moving mechanism, 10 ... object, 11 ... first substrate (board), 11a ... front surface (first main surface), 11b ... back surface (second main surface), 12 ... Functional element layer, 12a ... Metal layer, 34 ... First image pickup element, 35 ... Second image pickup element, 51 ... Focus position acquisition unit, 52 ... Processing position setting unit, 53 ... Storage unit, 54 ... Laser processing execution unit, KM ... Processing margin range, L ... Laser light (laser light for processing), L0 ... Transmitted light for observation, M1, M2, M3, M4, M5 ... Virtual surface.

Claims (16)

For an object having a substrate including a first main surface and a second main surface opposite to the first main surface, and a functional element layer provided on the first main surface side of the substrate and including a metal layer. A laser processing device that irradiates a processing laser beam to form a modified region inside the functional element layer along a virtual surface.
A support portion that supports the object and
A processing irradiation unit that irradiates the object with the processing laser light from the second main surface side, and a processing irradiation unit.
An observation irradiation unit that irradiates the object with the observation transmitted light transmitted through the substrate from the second main surface side.
A moving mechanism for moving at least one of the support portion, the processing irradiation portion, and the observation irradiation portion in the thickness direction of the object.
A focal position acquisition unit that acquires the position of the observation irradiation unit and / or the support unit in the thickness direction when the observation transmitted light is focused on the metal layer as the metal layer focal position.
With reference to the metal layer focal position acquired by the focal position acquisition unit, the position of the processing irradiation unit and / or the support portion in the thickness direction when forming the modified region is set to the laser processing position. A laser machining apparatus including a machining position setting unit to be set as. The laser processing according to claim 1, further comprising a first image pickup element having sensitivity to the transmitted transmitted light for observation and receiving reflected light reflected in response to irradiation of the transmitted transmitted light for observation from the irradiation irradiation unit for observation. Device. The first image pickup device has a higher sensitivity to the processing laser light, and further receives the reflected light reflected from the processing irradiation unit in response to the irradiation of the processing laser light, according to claim 2. Laser processing equipment. The movement mechanism is controlled based on the image pickup result of the first image pickup device, and the observation irradiation portion and / or the support portion is moved in the thickness direction so that the observation transmitted light is focused on the metal layer. The laser processing apparatus according to claim 2 or 3, further comprising an alignment portion to be moved. The focal position of the metal layer is represented by the coordinates of the irradiation portion for observation when the thickness direction is the coordinate axis on the support portion.
The laser processing apparatus according to any one of claims 1 to 4, wherein the laser processing position is represented by the coordinates of the processing irradiation unit when the thickness direction is the coordinate axis on the support portion. A storage unit for storing a predetermined reference focal position which is a reference value of the metal layer focal position and a predetermined reference processing position which is a reference value of the laser machining position is provided.
The machining position setting unit is
Any of claims 1 to 5, wherein the difference between the metal layer focal position and the reference focal position acquired by the focal position acquisition unit is obtained, and the laser processing position is set based on the difference and the reference processing position. The laser processing apparatus according to item 1. The laser processing apparatus according to claim 6, wherein the processing position setting unit sets a value obtained by adding or subtracting the reference processing position according to the difference or a correction value of the difference to the laser processing position. The reference machining position is the median value of the machining margin range.
The processing margin range is a case where the processing irradiation portion and / or the support portion is moved so that the condensing point of the processing laser beam moves in the thickness direction around the virtual surface. The laser processing apparatus according to claim 6 or 7, which is the range of the movement when the processing quality exceeds a certain level. The functional element is formed by locating the processing irradiation unit at the laser processing position set by the processing position setting unit by the moving mechanism and irradiating the object with the processing laser light from the processing irradiation unit. The laser processing apparatus according to any one of claims 1 to 8, further comprising a laser processing execution unit for forming the modified region inside the layer. The laser processing apparatus according to any one of claims 1 to 9, wherein the modified region is formed so as to spread over a partial region or the entire region of the functional element layer when viewed from the thickness direction. A laser processing head constituting the processing irradiation unit and the observation irradiation unit is provided.
The laser processing apparatus according to any one of claims 1 to 10, wherein the laser processing head coaxially emits the processing laser light and the observation transmitted light. A laser processing head constituting the processing irradiation unit and the observation irradiation unit is provided.
The laser processing apparatus according to any one of claims 1 to 10, wherein the laser processing head emits the processing laser light and the observation transmitted light on different axes. The laser processing head constituting the processing irradiation unit and
The laser processing apparatus according to any one of claims 1 to 10, further comprising an observation head that constitutes the observation irradiation unit and is separate from the laser processing head. Any of claims 1 to 13, further comprising a second image pickup device that has sensitivity to the processing laser light and receives reflected light reflected in response to irradiation of the processing laser light from the processing irradiation unit. The laser processing apparatus according to item 1. For an object having a substrate including a first main surface and a second main surface opposite to the first main surface, and a functional element layer provided on the first main surface side of the substrate and including a metal layer. This is a laser processing method in which a modified region is formed along a virtual surface inside the functional element layer by irradiating the processing laser light.
The step of supporting the object with the support portion and
A step of irradiating the object with the laser beam for processing from the second main surface side by the irradiation unit for processing.
The observation irradiation unit irradiates the object with the observation transmitted light transmitted through the substrate from the second main surface side, and the first image pickup element receives the reflected light reflected in response to the irradiation of the observation transmission light. Steps to do and
The observation irradiation portion and / or the support portion is moved in the thickness direction of the object based on the image pickup result of the first image pickup element, and the observation transmission light is focused on the metal layer. A step of acquiring the positions of the observation irradiation portion and / or the support portion in the thickness direction as the focal position of the metal layer, and
With reference to the acquired focal position of the metal layer, a step of setting the position of the irradiation portion for processing and / or the support portion in the thickness direction when forming the modified region as a laser processing position. Laser processing method. A reference value acquisition step for acquiring a reference focal position which is a reference value of the metal layer focal position and a reference processing position which is a reference value of the laser machining position is provided.
In the reference value acquisition step,
A step of supporting the object for reference setting with the support portion, and
The object for setting the reference is irradiated with the transmitted light for observation from the second main surface side, and the reflected light reflected in response to the irradiation of the transmitted light for observation is received by the first image pickup element, and the first image pickup device receives the reflected light. The observation in the thickness direction when the observation irradiation unit and / or the support portion is moved in the thickness direction based on the image pickup result of the image pickup element and the observation transmitted light is focused on the metal layer. A step of acquiring the position of the irradiation unit and / or the support portion as the reference focal position, and
The position of the processing irradiation portion and / or the support portion in the thickness direction is changed to irradiate the object for reference setting with the processing laser beam from the second main surface side, and the processing quality and the above. Including a step of acquiring the reference processing position based on the position of the processing irradiation portion and / or the support portion.
In the step of setting the laser processing position,
The laser processing method according to claim 15, wherein the difference between the acquired metal layer focal position and the reference focal position is obtained, and the laser processing position is set based on the difference and the reference processing position.

Images