WO2021220607A1 - Laser processing apparatus - Google Patents

Abstract

A laser processing apparatus focuses a portion of a light-condensing region onto an object and irradiates the object with a laser beam, thereby forming a modified region on the object. The laser processing apparatus comprises: a support unit that supports the object, the support unit being configured to be capable of rotating about an axis that follows the vertical direction; an irradiation unit that irradiates the object supported by the support unit with a laser beam in which a first horizontal direction is a polarizing direction; a first movement mechanism that causes the irradiation unit to move along the first horizontal direction, which is the polarizing direction; a second movement mechanism that causes the support unit and/or the irradiation unit to move in a second horizontal direction, which is a horizontal direction perpendicular to the polarizing direction; and a control unit that controls operations of the support unit, the irradiation unit, the first movement mechanism, and the second movement mechanism.

Description

Laser processing equipment

This disclosure relates to a laser processing apparatus.

There is known a laser processing device that forms a modified region on an object by irradiating the object with a part of the condensing region and irradiating it with laser light. As a technique of this type, Patent Document 1 describes a laser processing device including a holding mechanism for holding a work and a laser irradiation mechanism for irradiating a work held by the holding mechanism with a laser beam. In the laser processing apparatus described in Patent Document 1, a laser irradiation mechanism having a condensing lens is fixed to the base, and the movement of the work along the direction perpendicular to the optical axis of the condensing lens is performed by the holding mechanism. Will be implemented.

Japanese Patent No. 5456510

In the laser processing apparatus as described above, a modified region is formed on the object by relatively moving a part of the condensing region of the laser light irradiating the object. In such a laser machining apparatus, for example, in order to realize efficient laser machining, cracks are likely to grow from the modified region along a part of the moving direction of the condensing region (hereinafter, also referred to as "machining progress direction"). It may be desirable to do so.

Further, it is required that the laser processing apparatus as described above can be used for various laser processing such as trimming processing for removing the outer edge portion from the object as an unnecessary portion. However, in order to meet the demand, the mechanism for moving a part of the condensing region of the laser beam may become large, and the device configuration may become large.

Therefore, an object of the present disclosure is to provide a laser processing apparatus capable of easily extending cracks from a modified region along a moving direction of a laser beam while suppressing an increase in the size of the apparatus configuration.

The laser processing apparatus according to one aspect of the present disclosure is a laser processing apparatus that forms a modified region on an object by irradiating the object with a part of a condensing region and irradiating the laser beam. A support portion that is rotatably configured around an axis along the axis and supports the object, and an irradiation unit that irradiates the object supported by the support with a laser beam whose polarization direction is the first horizontal direction. Along the first horizontal direction that moves the irradiation unit along the first horizontal direction along the first horizontal direction that is the polarization direction, and the second horizontal direction that is the horizontal direction perpendicular to the polarization direction. A second moving mechanism that moves at least one of the support part and the irradiation part along the second horizontal direction, and a control part that controls the operation of the support part, the irradiation part, the first moving mechanism, and the second moving mechanism. Be prepared.

In the configuration of the laser processing apparatus according to one aspect of the present disclosure, it is possible to rotate the support portion and perform laser processing in which the tangential direction of the rotation is the polarization direction of the laser light (hereinafter, simply referred to as "polarization direction"). .. In addition, laser processing that linearly moves a part of the condensing region along the polarization direction becomes possible. That is, various laser machining in which the polarization direction is aligned with the machining progress direction becomes possible, and cracks can be easily extended along the machining progress direction. Further, in order to realize laser processing in which the polarization direction is aligned with the processing progress direction, in the configuration of the laser processing apparatus according to one aspect of the present disclosure, the drive direction of the support portion is only the rotation direction (uniaxial configuration). Or, it is reduced to only the rotation direction and the second horizontal direction (two-axis configuration). Since the support portion is generally heavy and large, it is possible to suppress an increase in the size of the device configuration by reducing the number of support portions in the drive direction (number of drive shafts). Therefore, according to one aspect of the present disclosure, it is possible to easily extend cracks from the modified region along the moving direction of the laser beam while suppressing an increase in the size of the apparatus configuration.

In the laser processing apparatus according to one aspect of the present disclosure, the control unit is an irradiation unit in a state where a part of the condensing region is aligned with a position separated from the axis of the support unit in the second horizontal direction in the object. Even if the first process of forming a modified region on the object along the annular line by rotating the support portion while irradiating the object with a laser beam having the first horizontal direction as the polarization direction is executed. good. In this case, the modified region along the annular line can be formed by laser machining in which the polarization direction is along the machining progress direction.

In the laser processing apparatus according to one aspect of the present disclosure, the control unit moves first along the first horizontal direction while irradiating the object with a laser beam having the first horizontal direction as the polarization direction from the irradiation unit. By moving the irradiation unit by the mechanism, the second process of forming the modified region on the object along the first horizontal linear line may be executed. In this case, the modified region along the linear line can be formed by laser machining in which the polarization direction is along the machining progress direction.

In the laser processing apparatus according to one aspect of the present disclosure, the control unit may execute the second process again after executing the second process, rotating the support unit to rotate the object by a certain angle, and then executing the second process again. In this case, a modified region along a plurality of linear lines extending in different directions can be formed by laser machining in which the polarization direction is along the machining progress direction.

In the laser processing apparatus according to one aspect of the present disclosure, the second moving mechanism may move only the irradiation unit. In this case, the drive direction of the support portion can be set to only the rotation direction (uniaxial configuration), and it is possible to further suppress the increase in size of the device configuration. Further, as the number of driving directions of the supporting portion is reduced, the degree of freedom in designing the supporting portion can be increased. In addition, the weight of the support portion can be reduced, and the rotation speed and rotation accuracy of the support portion can be improved.

In the laser processing apparatus according to one aspect of the present disclosure, the second moving mechanism may move only the support portion. In this case, the degree of freedom in designing the irradiation unit can be increased as the number of driving directions of the irradiation unit decreases. Further, since the irradiation unit does not move during irradiation with the laser beam, it is possible to reduce the vibration applied to the laser beam and its optical system.

The laser processing apparatus according to one aspect of the present disclosure further includes a third moving mechanism for moving the irradiation unit along the vertical direction, and the control unit may further control the operation of the third moving mechanism. In this case, by moving the irradiation unit by the third moving mechanism, it is possible to move a part of the condensing region of the laser beam in the vertical direction.

According to the present disclosure, it is possible to provide a laser processing apparatus capable of easily extending cracks from a modified region along a moving direction of a laser beam while suppressing an increase in the size of the apparatus configuration.

FIG. 1 is a perspective view of the laser processing apparatus of one embodiment. FIG. 2 is a front view of a part of the laser processing apparatus shown in FIG. FIG. 3 is a front view of the laser processing head of the laser processing apparatus shown in FIG. FIG. 4 is a side view of the laser machining head shown in FIG. FIG. 5 is a block diagram of the optical system of the laser processing head shown in FIG. FIG. 6 is a block diagram of the optical system of the laser processing head of the modified example. FIG. 7 is a front view of a part of the laser processing apparatus of the modified example. FIG. 8 is a configuration diagram showing a main part of the laser processing apparatus according to the first embodiment. FIG. 9A is a plan view showing an object to be laser machined. FIG. 9B is a side view showing an object to be laser machined. FIG. 10 is a plan view illustrating laser processing by the laser processing apparatus of FIG. FIG. 11 is a plan view showing a continuation of FIG. FIG. 12 is a plan view showing a continuation of FIG. FIG. 13 is a plan view showing a continuation of FIG. FIG. 14 is a plan view showing the continuation of FIG. FIG. 15 is a plan view showing the continuation of FIG. FIG. 16 is a plan view showing a continuation of FIG. FIG. 17 is a plan view showing a continuation of FIG. FIG. 18 is a configuration diagram showing a main part of the laser processing apparatus according to the second embodiment. FIG. 19 is a plan view illustrating laser processing by the laser processing apparatus of FIG. FIG. 20 is a plan view showing a continuation of FIG. FIG. 21 is a plan view showing a continuation of FIG. 20. FIG. 22 is a plan view showing a continuation of FIG. 21.

Hereinafter, embodiments 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.
[Construction of laser processing equipment]

As shown in FIG. 1, the laser machining apparatus 1 includes a plurality of moving mechanisms 5 and 6, a support portion 7, a pair of laser machining heads 10A and 10B, a light source unit 8, and a control unit 9. I have. Hereinafter, the first horizontal direction is referred to as an X direction, the second horizontal direction which is a horizontal direction perpendicular to the first horizontal direction is referred to as a Y direction, and the vertical direction is referred to as a Z direction.

The moving mechanism 5 has a fixed portion 51, a moving portion 53, and a mounting portion 55. The fixing portion 51 is attached to the device frame 1a. The moving portion 53 is attached to a rail provided on the fixed portion 51, and can move along the Y direction. The mounting portion 55 is mounted on a rail provided on the moving portion 53, and can move along the X direction.

The moving mechanism 6 has a fixed portion 61, a pair of moving portions 63, 64, and a pair of mounting portions 65, 66. The fixing portion 61 is attached to the device frame 1a. Each of the pair of moving portions 63 and 64 is attached to a rail provided on the fixed portion 61, and each of them can move independently in the Y direction. The mounting portion 65 is mounted on a rail provided on the moving portion 63, and can move along the Z direction. The mounting portion 66 is mounted on a rail provided on the moving portion 64 and can move along the Z direction. That is, with respect to the device frame 1a, each of the pair of mounting portions 65 and 66 can move along the Y direction and the Z direction, respectively.

The support portion 7 is attached to a rotating shaft provided in the mounting portion 55 of the moving mechanism 5, and can rotate with an axis parallel to the Z direction as the center line. That is, the support portion 7 can move along each of the X direction and the Y direction, and can rotate with the axis parallel to the Z direction as the center line. The support portion 7 supports the object 100 along the X and Y directions. The object 100 is, for example, a wafer.

As shown in FIGS. 1 and 2, the laser machining head 10A is attached to the attachment portion 65 of the moving mechanism 6. The laser processing head 10A is for irradiating the object 100 supported by the support portion 7 with the laser beam L1 in a state of facing the support portion 7 in the Z direction. The laser machining head 10B is attached to the attachment portion 66 of the moving mechanism 6. The laser processing head 10B is for irradiating the object 100 supported by the support portion 7 with the laser beam L2 in a state of facing the support portion 7 in the Z direction.

The light source unit 8 has a pair of light sources 81 and 82. The light source 81 outputs the laser beam L1. The laser beam L1 is emitted from the exit portion 81a of the light source 81, and is guided to the laser processing head 10A by the optical fiber 2. The light source 82 outputs the laser beam L2. The laser beam L2 is emitted from the exit portion 82a of the light source 82, and is guided to the laser processing head 10B by another optical fiber 2.

The control unit 9 controls each unit of the laser processing device 1 (a plurality of moving mechanisms 5, 6, a pair of laser processing heads 10A, 10B, a light source unit 8, etc.). The control unit 9 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 9, software (program) read into the memory or the like is executed by the processor, and reading and writing of data in the memory and storage and communication by the communication device are controlled by the processor. As a result, the control unit 9 realizes various functions.

An example of processing by the laser processing apparatus 1 configured as described above will be described. An example of this processing is an example in which a modification region is formed inside the object 100 along each of a plurality of lines set in a grid pattern in order to cut the object 100, which is a wafer, into a plurality of chips. be.

First, the moving mechanism 5 moves the support portion 7 along the X direction and the Y direction so that the support portion 7 supporting the object 100 faces the pair of laser machining heads 10A and 10B in the Z direction. To move. Subsequently, the moving mechanism 5 rotates the support portion 7 with the axis parallel to the Z direction as the center line so that the plurality of lines extending in one direction in the object 100 are along the X direction.

Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the condensing point of the laser beam L1 is located on one line extending in one direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the condensing point of the laser beam L2 is located on another line extending in one direction. Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the condensing point of the laser beam L1 is located inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focusing point of the laser beam L2 is located inside the object 100.

Subsequently, the light source 81 outputs the laser light L1 and the laser processing head 10A irradiates the object 100 with the laser light L1, the light source 82 outputs the laser light L2, and the laser processing head 10B lasers the object 100. Irradiate light L2. At the same time, the focusing point of the laser beam L1 moves relatively along one line extending in one direction (the laser beam L1 is scanned), and the laser along the other line extending in one direction. The moving mechanism 5 moves the support portion 7 along the X direction so that the focusing point of the light L2 moves relatively (the laser light L2 is scanned). In this way, the laser machining apparatus 1 forms a modified region inside the object 100 along each of the plurality of lines extending in one direction in the object 100.

Subsequently, the moving mechanism 5 rotates the support portion 7 with the axis parallel to the Z direction as the center line so that a plurality of lines extending in the other direction orthogonal to one direction of the object 100 are along the X direction. ..

Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the condensing point of the laser beam L1 is located on one line extending in the other direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the condensing point of the laser beam L2 is located on another line extending in the other direction. Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the condensing point of the laser beam L1 is located inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focusing point of the laser beam L2 is located inside the object 100.

Subsequently, the light source 81 outputs the laser light L1 and the laser processing head 10A irradiates the object 100 with the laser light L1, the light source 82 outputs the laser light L2, and the laser processing head 10B lasers the object 100. Irradiate light L2. At the same time, the focusing point of the laser beam L1 moves relatively along one line extending in the other direction (the laser beam L1 is scanned), and the laser along the other line extending in the other direction. The moving mechanism 5 moves the support portion 7 along the X direction so that the focusing point of the light L2 moves relatively (the laser light L2 is scanned). In this way, the laser machining apparatus 1 forms a modified region inside the object 100 along each of a plurality of lines extending in the other direction orthogonal to one direction in the object 100.

In one example of the above-mentioned processing, the light source 81 outputs the laser beam L1 having transparency to the object 100 by, for example, a pulse oscillation method, and the light source 82 is directed to the object 100 by, for example, a pulse oscillation method. On the other hand, the laser beam L2 having transparency is output. When such laser light is focused inside the object 100, the laser light is particularly absorbed at the portion corresponding to the focusing point of the laser light, and a modified region is formed inside the object 100. 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. Examples of the modified region include a melting treatment region, a crack region, a dielectric breakdown region, a refractive index change region, and the like.

When the laser beam output by the pulse oscillation method is applied to the object 100 and the focusing point of the laser light is relatively moved along the line set on the object 100, a plurality of modified spots are lined up. It is formed so as to line up in a row along the line. One modified spot is formed by irradiation with one pulse of laser light. A modification region in one row is a set of a plurality of modification spots arranged in one row. Adjacent modified spots may be connected to each other or separated from each other depending on the relative moving speed of the focusing point of the laser light with respect to the object 100 and the repetition frequency of the laser light.
[Laser machining head configuration]

As shown in FIGS. 3 and 4, the laser processing head 10A includes a housing 11, an incident portion 12, an adjusting portion 13, and a condensing portion 14.

The housing 11 has a first wall portion 21, a second wall portion 22, a third wall portion 23 and a fourth wall portion 24, and a fifth wall portion 25 and a sixth wall portion 26. The first wall portion 21 and the second wall portion 22 face each other in the X direction. The third wall portion 23 and the fourth wall portion 24 face each other in the Y direction. The fifth wall portion 25 and the sixth wall portion 26 face each other in the Z direction.

The distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22. The distance between the first wall portion 21 and the second wall portion 22 is smaller than the distance between the fifth wall portion 25 and the sixth wall portion 26. The distance between the first wall portion 21 and the second wall portion 22 may be equal to the distance between the fifth wall portion 25 and the sixth wall portion 26, or the fifth wall portion 25 and the sixth wall portion 26. It may be larger than the distance to the part 26.

In the laser machining head 10A, the first wall portion 21 is located on the fixed portion 61 side of the moving mechanism 6, and the second wall portion 22 is located on the opposite side of the fixed portion 61. The third wall portion 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall portion 24 is located on the opposite side of the mounting portion 65 and on the laser machining head 10B side (FIG. 6). 2). That is, the fourth wall portion 24 is an opposing wall portion that faces the housing of the laser processing head 10B along the Y direction. The fifth wall portion 25 is located on the side opposite to the support portion 7, and the sixth wall portion 26 is located on the support portion 7 side.

The housing 11 is configured so that the housing 11 can be mounted on the mounting portion 65 with the third wall portion 23 arranged on the mounting portion 65 side of the moving mechanism 6. Specifically, it is as follows. The mounting portion 65 includes a base plate 65a and a mounting plate 65b. The base plate 65a is attached to a rail provided on the moving portion 63 (see FIG. 2). The mounting plate 65b is erected at the end of the base plate 65a on the laser machining head 10B side (see FIG. 2). The housing 11 is attached to the mounting portion 65 by screwing the bolt 28 into the mounting plate 65b via the pedestal 27 in a state where the third wall portion 23 is in contact with the mounting plate 65b. The pedestal 27 is provided on each of the first wall portion 21 and the second wall portion 22. The housing 11 is removable from the mounting portion 65.

The incident portion 12 is attached to the fifth wall portion 25. The incident portion 12 causes the laser beam L1 to enter the housing 11. The incident portion 12 is offset toward the second wall portion 22 in the X direction, and is offset toward the fourth wall portion 24 in the Y direction. That is, the distance between the incident portion 12 and the second wall portion 22 in the X direction is smaller than the distance between the incident portion 12 and the first wall portion 21 in the X direction, and the incident portion 12 and the fourth wall portion 24 in the Y direction. The distance to and from is smaller than the distance between the incident portion 12 and the third wall portion 23 in the X direction.

The incident portion 12 is configured so that the connection end portion 2a of the optical fiber 2 can be connected. The connection end 2a of the optical fiber 2 is provided with a collimator lens that collimates the laser beam L1 emitted from the emission end of the fiber, and is not provided with an isolator that suppresses the return light. The isolator is provided in the middle of the fiber which is closer to the light source 81 than the connection end 2a. As a result, the connection end portion 2a is downsized, and the incident portion 12 is downsized. An isolator may be provided at the connection end 2a of the optical fiber 2.

The adjusting unit 13 is arranged in the housing 11. The adjusting unit 13 adjusts the laser beam L1 incident from the incident unit 12. Each configuration of the adjusting unit 13 is attached to an optical base 29 provided in the housing 11. The optical base 29 is attached to the housing 11 so as to partition the region inside the housing 11 into a region on the third wall portion 23 side and a region on the fourth wall portion 24 side. The optical base 29 is integrated with the housing 11. Each configuration of the adjusting portion 13 is attached to the optical base 29 on the fourth wall portion 24 side. Details of each configuration of the adjusting unit 13 will be described later.

The light collecting portion 14 is arranged on the sixth wall portion 26. Specifically, the light collecting portion 14 is arranged in the sixth wall portion 26 in a state of being inserted into the hole 26a formed in the sixth wall portion 26. The condensing unit 14 condenses the laser beam L1 adjusted by the adjusting unit 13 and emits it to the outside of the housing 11. The light collecting portion 14 is biased toward the second wall portion 22 in the X direction, and is offset toward the fourth wall portion 24 in the Y direction. That is, the light collecting portion 14 is arranged unevenly toward the fourth wall portion 24 side of the housing 11 when viewed from the Z direction. That is, the distance between the condensing unit 14 and the second wall portion 22 in the X direction is smaller than the distance between the condensing unit 14 and the first wall portion 21 in the X direction, and the condensing unit 14 and the fourth in the Y direction. The distance to the wall portion 24 is smaller than the distance between the condensing portion 14 and the third wall portion 23 in the X direction.

As shown in FIG. 5, the adjusting unit 13 has an attenuator 31, a beam expander 32, and a mirror 33. The incident portion 12, the attenuator 31, the beam expander 32, and the mirror 33 of the adjusting portion 13 are arranged on a straight line A1 extending along the Z direction. The attenuator 31 and the beam expander 32 are arranged between the incident portion 12 and the mirror 33 on the straight line A1. The attenuator 31 adjusts the output of the laser beam L1 incident from the incident portion 12. The beam expander 32 expands the diameter of the laser beam L1 whose output is adjusted by the attenuator 31. The mirror 33 reflects the laser beam L1 whose diameter has been expanded by the beam expander 32.

The adjusting unit 13 further includes a reflective spatial light modulator 34 and an imaging optical system 35. The reflective spatial light modulator 34 and the imaging optical system 35 of the adjusting unit 13 and the condensing unit 14 are arranged on a straight line A2 extending along the Z direction. The reflective spatial light modulator 34 modulates the laser beam L1 reflected by the mirror 33. The reflective spatial light modulator 34 is, for example, a spatial light modulator (SLM: Spatial Light Modulator) of a reflective liquid crystal (LCOS: Liquid Crystal on Silicon). The imaging optical system 35 constitutes a bilateral telecentric optical system in which the reflecting surface 34a of the reflective spatial light modulator 34 and the entrance pupil surface 14a of the condensing unit 14 are in an imaging relationship. The imaging optical system 35 is composed of three or more lenses.

The straight line A1 and the straight line A2 are located on a plane perpendicular to the Y direction. The straight line A1 is located on the second wall portion 22 side with respect to the straight line A2. In the laser processing head 10A, the laser beam L1 enters the housing 11 from the incident portion 12, travels on the straight line A1, is sequentially reflected by the mirror 33 and the reflective spatial light modulator 34, and then the straight line A2. Proceeding upward, the light is emitted from the light collecting unit 14 to the outside of the housing 11. The order of arrangement of the attenuator 31 and the beam expander 32 may be reversed. Further, the attenuator 31 may be arranged between the mirror 33 and the reflective spatial light modulator 34. Further, the adjusting unit 13 may have other optical components (for example, a steering mirror arranged in front of the beam expander 32).

The laser processing head 10A further includes a dichroic mirror 15, a measuring unit 16, an observing unit 17, a driving unit 18, and a circuit unit 19.

The dichroic mirror 15 is arranged between the imaging optical system 35 and the condensing unit 14 on the straight line A2. That is, the dichroic mirror 15 is arranged between the adjusting unit 13 and the condensing unit 14 in the housing 11. The dichroic mirror 15 is attached to the optical base 29 on the fourth wall portion 24 side. The dichroic mirror 15 transmits the laser beam L1. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 may be, for example, a cube type or a two-plate type arranged so as to have a twisting relationship.

The measuring unit 16 is arranged on the first wall 21 side with respect to the adjusting unit 13 in the housing 11. The measuring unit 16 is attached to the optical base 29 on the side of the fourth wall unit 24. The measuring unit 16 outputs the measuring light L10 for measuring the distance between the surface of the object 100 (for example, the surface on the side where the laser light L1 is incident) and the condensing unit 14, and outputs the measuring light L10 via the condensing unit 14. , The measurement light L10 reflected on the surface of the object 100 is detected. That is, the measurement light L10 output from the measurement unit 16 irradiates the surface of the object 100 via the condensing unit 14, and the measurement light L10 reflected on the surface of the object 100 passes through the condensing unit 14. Is detected by the measuring unit 16.

More specifically, the measurement light L10 output from the measurement unit 16 is sequentially reflected by the beam splitter 20 and the dichroic mirror 15 attached to the optical base 29 on the fourth wall portion 24 side, and is reflected from the condensing unit 14. It is emitted to the outside of the housing 11. The measurement light L10 reflected on the surface of the object 100 is incident on the housing 11 from the condensing unit 14 and is sequentially reflected by the dichroic mirror 15 and the beam splitter 20, and is incident on the measurement unit 16 and is incident on the measurement unit 16. Is detected by.

The observation unit 17 is arranged on the first wall 21 side with respect to the adjustment unit 13 in the housing 11. The observation unit 17 is attached to the optical base 29 on the side of the fourth wall unit 24. The observation unit 17 outputs the observation light L20 for observing the surface of the object 100 (for example, the surface on the side where the laser beam L1 is incident) and reflects the light L20 on the surface of the object 100 via the condensing unit 14. The observed light L20 is detected. That is, the observation light L20 output from the observation unit 17 irradiates the surface of the object 100 via the condensing unit 14, and the observation light L20 reflected on the surface of the object 100 passes through the condensing unit 14. Is detected by the observation unit 17.

More specifically, the observation light L20 output from the observation unit 17 passes through the beam splitter 20 and is reflected by the dichroic mirror 15, and is emitted from the light collection unit 14 to the outside of the housing 11. The observation light L20 reflected on the surface of the object 100 enters the housing 11 from the condensing unit 14, is reflected by the dichroic mirror 15, passes through the beam splitter 20 and is incident on the observation unit 17, and is incident on the observation unit 17. Detected at 17. The wavelengths of the laser light L1, the measurement light L10, and the observation light L20 are different from each other (at least the center wavelengths of the laser light L1 are deviated from each other).

The drive unit 18 is attached to the optical base 29 on the side of the fourth wall unit 24. The driving unit 18 moves the condensing unit 14 arranged on the sixth wall unit 26 along the Z direction by, for example, the driving force of the piezoelectric element.

The circuit unit 19 is arranged on the third wall portion 23 side with respect to the optical base 29 in the housing 11. That is, the circuit unit 19 is arranged in the housing 11 on the third wall portion 23 side with respect to the adjusting unit 13, the measuring unit 16, and the observing unit 17. The circuit unit 19 is, for example, a plurality of circuit boards. The circuit unit 19 processes the signal output from the measurement unit 16 and the signal input to the reflective spatial light modulator 34. The circuit unit 19 controls the drive unit 18 based on the signal output from the measurement unit 16. As an example, the circuit unit 19 is such that the distance between the surface of the object 100 and the condensing unit 14 is kept constant (that is, with the surface of the object 100) based on the signal output from the measuring unit 16. The drive unit 18 is controlled so that the distance of the laser beam L1 from the condensing point is kept constant). The housing 11 is provided with a connector (not shown) to which wiring for electrically connecting the circuit unit 19 to the control unit 9 (see FIG. 1) or the like is connected.

Similar to the laser processing head 10A, the laser processing head 10B includes a housing 11, an incident unit 12, an adjusting unit 13, a condensing unit 14, a dichroic mirror 15, a measuring unit 16, and an observing unit 17. A drive unit 18 and a circuit unit 19 are provided. However, as shown in FIG. 2, each configuration of the laser machining head 10B is a configuration of the laser machining head 10A with respect to a virtual plane passing through the midpoint between the pair of mounting portions 65 and 66 and perpendicular to the Y direction. It is arranged so as to have a plane-symmetrical relationship with.

For example, in the housing 11 of the laser machining head 10A, the fourth wall portion 24 is located on the laser machining head 10B side with respect to the third wall portion 23, and the sixth wall portion 26 supports the fifth wall portion 25. It is attached to the attachment portion 65 so as to be located on the portion 7 side. On the other hand, in the housing 11 of the laser machining head 10B, the fourth wall portion 24 is located on the laser machining head 10A side with respect to the third wall portion 23, and the sixth wall portion 26 is relative to the fifth wall portion 25. It is attached to the attachment portion 66 so as to be located on the support portion 7 side. That is, also in the laser machining head 10B, the fourth wall portion 24 is a facing wall portion facing the housing of the laser machining head 10A along the Y direction. Further, also in the laser processing head 10B, the condensing portion 14 is unevenly arranged on the fourth wall portion (opposing wall portion) 24 side of the housing 11 when viewed from the Z direction.

The housing 11 of the laser machining head 10B is configured so that the housing 11 can be mounted on the mounting portion 66 with the third wall portion 23 arranged on the mounting portion 66 side. Specifically, it is as follows. The mounting portion 66 has a base plate 66a and a mounting plate 66b. The base plate 66a is attached to a rail provided on the moving portion 63. The mounting plate 66b is erected at the end of the base plate 66a on the laser machining head 10A side. The housing 11 of the laser machining head 10B is attached to the mounting portion 66 with the third wall portion 23 in contact with the mounting plate 66b. The housing 11 of the laser machining head 10B is removable from the mounting portion 66.
[Action and effect of laser machining head]

In the laser processing head 10A, since the light source for outputting the laser beam L1 is not provided in the housing 11, the size of the housing 11 can be reduced. Further, in the housing 11, the distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22, and the collection is arranged on the sixth wall portion 26. The light portion 14 is offset toward the fourth wall portion 24 in the Y direction. As a result, when the housing 11 is moved along the direction perpendicular to the optical axis of the condensing unit 14, for example, if another configuration (for example, the laser processing head 10B) is present on the fourth wall portion 24 side. Also, the condensing unit 14 can be brought closer to the other configuration. Therefore, the laser processing head 10A may move the condensing unit 14 along the direction perpendicular to its optical axis.

Further, in the laser processing head 10A, the incident portion 12 is provided on the fifth wall portion 25, and is offset toward the fourth wall portion 24 in the Y direction. As a result, it is possible to effectively use the area such as arranging another configuration (for example, the circuit unit 19) in the area on the third wall portion 23 side with respect to the adjusting portion 13 in the region in the housing 11. can.

Further, in the laser processing head 10A, the condensing portion 14 is offset toward the second wall portion 22 in the X direction. As a result, when the housing 11 is moved along the direction perpendicular to the optical axis of the condensing unit 14, for example, even if another configuration exists on the second wall portion 22 side, it is concentrated in the other configuration. The optical unit 14 can be brought closer.

Further, in the laser machining head 10A, the incident portion 12 is provided on the fifth wall portion 25 and is offset toward the fourth wall portion 24 in the Y direction and is offset toward the second wall portion 22 in the X direction. ing. As a result, it is possible to effectively use the area such as arranging another configuration (for example, the circuit unit 19) in the area on the third wall portion 23 side with respect to the adjusting portion 13 in the region in the housing 11. can. Further, other configurations (for example, the measuring unit 16 and the observing unit 17) are arranged in the area on the first wall 21 side with respect to the adjusting unit 13 in the area in the housing 11, and the area is effectively used. can do.

Further, in the laser machining head 10A, the measuring unit 16 and the observing unit 17 are arranged in a region on the first wall portion 21 side of the region in the housing 11 with respect to the adjusting portion 13, and the circuit unit 19 is arranged. Of the area inside the housing 11, the dichroic mirror 15 is arranged on the third wall portion 23 side with respect to the adjusting portion 13, and the dichroic mirror 15 is arranged between the adjusting portion 13 and the condensing portion 14 in the housing 11. ing. As a result, the area inside the housing 11 can be effectively used. Further, in the laser processing apparatus 1, processing based on the measurement result of the distance between the surface of the object 100 and the condensing unit 14 becomes possible. Further, in the laser processing apparatus 1, processing based on the observation result of the surface of the object 100 becomes possible.

Further, in the laser machining head 10A, the circuit unit 19 controls the drive unit 18 based on the signal output from the measurement unit 16. Thereby, the position of the condensing point of the laser beam L1 can be adjusted based on the measurement result of the distance between the surface of the object 100 and the condensing portion 14.

Further, in the laser processing head 10A, the incident portion 12, the attenuator 31, the beam expander 32, and the mirror 33 of the adjusting portion 13 are arranged on the straight line A1 extending along the Z direction, and the adjusting portion 13 The reflective spatial light modulator 34, the imaging optical system 35, the condensing unit 14, and the condensing unit 14 are arranged on a straight line A2 extending along the Z direction. As a result, the adjusting unit 13 having the attenuator 31, the beam expander 32, the reflective spatial light modulator 34, and the imaging optical system 35 can be compactly configured.

Further, in the laser processing head 10A, the straight line A1 is located on the second wall portion 22 side with respect to the straight line A2. As a result, in the region on the first wall portion 21 side with respect to the adjusting portion 13 in the region inside the housing 11, another optical system using the condensing unit 14 (for example, the measuring unit 16 and the observing unit 17) is provided. When it is configured, the degree of freedom in the configuration of the other optical system can be improved.

The above actions and effects are similarly exhibited by the laser processing head 10B.
[Variation example of laser processing head]

As shown in FIG. 6, the incident portion 12, the adjusting portion 13, and the condensing portion 14 may be arranged on a straight line A extending along the Z direction. According to this, the adjusting unit 13 can be configured compactly. In that case, the adjusting unit 13 may not have the reflective spatial light modulator 34 and the imaging optical system 35. Further, the adjusting unit 13 may have an attenuator 31 and a beam expander 32. According to this, the adjusting unit 13 having the attenuator 31 and the beam expander 32 can be compactly configured. The order of arrangement of the attenuator 31 and the beam expander 32 may be reversed.

Further, the light guide of the laser beam L1 from the exit portion 81a of the light source unit 8 to the incident portion 12 of the laser processing head 10A, and the laser beam L2 from the exit portion 82a of the light source unit 8 to the incident portion 12 of the laser processing head 10B. At least one of the light guides may be carried out by a mirror. FIG. 7 is a front view of a part of the laser processing apparatus 1 in which the laser beam L1 is guided by a mirror. In the configuration shown in FIG. 7, the mirror 3 that reflects the laser beam L1 moves so as to face the emitting portion 81a of the light source unit 8 in the Y direction and the incident portion 12 of the laser processing head 10A in the Z direction. It is attached to the moving portion 63 of the mechanism 6.

In the configuration shown in FIG. 7, even if the moving portion 63 of the moving mechanism 6 is moved along the Y direction, the state in which the mirror 3 faces the emitting portion 81a of the light source unit 8 in the Y direction is maintained. Further, even if the mounting portion 65 of the moving mechanism 6 is moved along the Z direction, the state in which the mirror 3 faces the incident portion 12 of the laser processing head 10A in the Z direction is maintained. Therefore, regardless of the position of the laser processing head 10A, the laser light L1 emitted from the emitting portion 81a of the light source unit 8 can be reliably incident on the incident portion 12 of the laser processing head 10A. Moreover, a light source such as a high-output long-short pulse laser, which is difficult to guide by the optical fiber 2, can also be used.

Further, in the configuration shown in FIG. 7, the mirror 3 may be attached to the moving portion 63 of the moving mechanism 6 so that at least one of angle adjustment and position adjustment is possible. According to this, the laser beam L1 emitted from the emitting portion 81a of the light source unit 8 can be more reliably incident on the incident portion 12 of the laser processing head 10A.

Further, the light source unit 8 may have one light source. In that case, the light source unit 8 may be configured so that a part of the laser light output from one light source is emitted from the emitting unit 81a and the remaining portion of the laser light is emitted from the emitting unit 82a.

<First Embodiment>
Next, the first embodiment will be described. Hereinafter, the description overlapping with the above-described embodiment will be omitted.

As shown in FIG. 8, the laser processing apparatus 101 according to the first embodiment irradiates the object 100 with a part of the condensing region (hereinafter, also referred to as a “condensing point”) and irradiates the laser beam L1. This is an apparatus for forming a modified region on the object 100. The laser processing apparatus 101 is an apparatus for acquiring (manufacturing) a semiconductor device by performing laser processing including trimming processing and radiation cutting processing on an object 100.

The trimming process is a process for removing unnecessary parts in the object 100. The radiant cut process is a process for separating the unnecessary portion to be removed by the trimming process. The trimming process and the radiation cutting process include a laser processing method for forming a modified region on the object 100 by aligning a condensing point on the object 100 and irradiating the object 100 with laser light L1.

The object 100 includes, for example, a semiconductor wafer formed in a disk shape. The object 100 is not particularly limited, and may be formed of various materials or may have various shapes. A functional element (not shown) is formed on the surface 100a of the object 100. The functional element is, for example, 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.

As shown in FIGS. 9 (a) and 9 (b), an effective region R and a removal region E are set in the object 100. The effective domain R is a portion corresponding to the semiconductor device to be acquired. The effective region R here is a disk-shaped portion including a central portion when the object 100 is viewed from the thickness direction. The removal region E is a region outside the effective region R of the object 100. The removal region E is an outer edge portion of the object 100 other than the effective region R. The removal region E here is an annular portion surrounding the effective region R. The removal region E includes a peripheral portion (bevel portion of the outer edge) when the object 100 is viewed from the thickness direction. The effective region R and the removal region E can be set by the control unit 9. The effective region R and the removal region E may have coordinates specified.

A line M3 as a trimming scheduled line is set for the object 100. The line M3 is a line scheduled to form the modified region 4. The line M3 is an annular line extending in an annular shape inside the outer edge of the object 100. The line M3 here extends in an annular shape. The line M3 is set at the boundary between the effective region R and the removal region E of the object 100. Further, the object 100 is set with a line M4 as a planned radiation cut line. Line M4 is a line scheduled to form a modified region by radiation cutting. The line M4 is a linear line extending linearly (radially) along the radial direction of the object 100 when viewed from the laser beam incident surface. For example, a plurality of lines M4 are set so that the removal region E is equally divided (here, divided into four) in the circumferential direction when viewed from the laser beam incident surface. The lines M3 and M4 are virtual lines, but may be lines actually drawn. The lines M3 and M4 can be set by the control unit 9. The lines M3 and M4 may have coordinates specified.

The object 100 may be provided with an alignment target (not shown). For example, the alignment target has a certain relationship in the θ direction (rotational direction around the axis C of the support portion 7) with respect to the position of the object 100 in the 0 ° direction. The position in the 0 ° direction is the position of the reference object 100 in the θ direction. For example, the alignment target includes a notch formed on the outer edge portion, an orientation flat, or a pattern of a functional element.

As shown in FIG. 8, the laser processing apparatus 101 includes a support portion 7, a laser processing head (irradiation portion) 10A, an X-direction moving mechanism (first moving mechanism) 110, and a Y-direction moving mechanism (second moving mechanism) 120. , Z-direction moving mechanism (third moving mechanism) 130, and control unit 9.

The support unit 7 supports the object 100. For example, the object 100 is placed on the support portion 7 with the back surface 100b of the object 100 on the upper side on the laser beam incident surface side (the surface 100a on the lower side on the stage 107 side). .. The support portion 7 has an axis C (see FIG. 9) provided at the center thereof and along the Z direction. The support portion 7 can rotate in the θ direction about the axis C. The support portion 7 is rotationally driven by the driving force of a known driving device such as a motor.

The laser processing head 10A irradiates the object 100 supported by the support portion 7 with laser light L1 having the X direction as the polarization direction in the Z direction to form a modified region inside the object 100. .. The polarization direction of the laser beam L1 (hereinafter, also simply referred to as “polarization direction”) can be controlled by the reflection type spatial light modulator 34 included in the laser processing head 10A. Specifically, by displaying a modulation pattern including a predetermined slit pattern on the liquid crystal layer of the reflective spatial light modulator 34, the reflective spatial light modulator 34 functions as a polarizer, and the polarized light L1 is polarized. The direction is adjusted to the X direction. The modulation pattern is a hologram pattern that imparts modulation. The predetermined slit pattern is preset and stored in the control unit 9. The polarization direction of the laser beam L1 is not limited to the control using the reflective spatial light modulator 34, and may be controlled by using various known techniques. For example, the polarization direction of the laser beam L1 may be adjusted in the X direction by using a λ / 2 wave plate. The laser processing head 10A constitutes an irradiation unit.

As shown in FIGS. 8 and 10, the Z direction moving mechanism 130 is a mechanism for moving the laser machining head 10A along the Z direction. The Z-direction moving mechanism 130 has a Z-axis rail 130A. The Z-axis rail 130A is a rail extending along the Z direction. The Z-axis rail 130A is attached to the laser machining head 10A via the attachment portion 65. In such a Z-direction moving mechanism 130, the laser processing head 10A is moved to the Z-axis rail 130A so that the condensing point of the laser light L1 moves along the Z direction by the driving force of a known driving device such as a motor. Move along the Z direction. The Z-direction moving mechanism 130 corresponds to a part of the moving mechanism 6 (see FIG. 1).

The X-direction moving mechanism 110 is a mechanism for moving the laser processing head 10A along the X direction, which is the polarization direction. The X-direction moving mechanism 110 has an X-axis rail 110A. The X-axis rail 110A is a rail extending along the X direction. The X-axis rail 110A is attached to the laser machining head 10A via the Z-axis rail 130A and the attachment portion 65. In such an X-direction moving mechanism 110, the laser processing head 10A is moved to the X-axis rail 110A so that the condensing point of the laser light L1 moves along the X direction by the driving force of a known driving device such as a motor. Move along the X direction.

The Y-direction moving mechanism 120 is a mechanism for moving the laser machining head 10A along the Y-direction. The Y-direction moving mechanism 120 has a Y-axis rail 120A. The Y-axis rail 120A is a rail extending along the Y direction. The Y-axis rail 120A is attached to the laser machining head 10A via the X-axis rail 110A, the Z-axis rail 130A, and the attachment portion 65. In such a Y-direction moving mechanism 120, the laser processing head 10A is moved to the Y-axis rail 120A so that the condensing point of the laser light L1 moves along the Y direction by the driving force of a known driving device such as a motor. Move along the Y direction. The Y-direction moving mechanism 120 corresponds to a part of the moving mechanism 6 (see FIG. 1).

The control unit 9 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 9, software (program) read into the memory or the like is executed by the processor, and reading and writing of data in the memory and storage and communication by the communication device are controlled by the processor. As a result, the control unit 9 realizes various functions.

The control unit 9 controls the operations of the support unit 7, the laser machining head 10A, the X-direction moving mechanism 110, the Y-direction moving mechanism 120, and the Z-direction moving mechanism 130. The control unit 9 controls the rotation of the support unit 7, the irradiation of the laser beam L1 from the laser processing head 10A, and the movement of the focusing point of the laser beam L1. The control unit 9 can execute various controls based on the rotation information (hereinafter, also referred to as “θ information”) regarding the rotation amount of the support unit 7. The θ information may be acquired from the driving amount of the driving device that rotates the support portion 7, or may be acquired by a separate sensor or the like. θ information can be obtained by various known methods. The θ information here includes a rotation angle based on the state when the object 100 is located at a position in the 0 ° direction.

The control unit 9 irradiates the laser beam L1 on the laser processing head 10A based on the θ information in a state where the condensing point is positioned along the line M3 on the object 100 while rotating the support unit 7. By controlling the start and stop, a trimming process (first process) for forming a modified region along the peripheral edge of the effective region R is executed. In the trimming process, a laser in which the X direction is the polarization direction from the laser processing head 10A in a state where the condensing point is aligned with the position on the line M3 separated from the axis C of the support portion 7 in the Y direction in the object 100. By rotating the support portion 7 while irradiating the object 100 with the light L1, a modified region is formed on the object 100 along the line M3. The control unit 9 repeatedly executes the trimming process a plurality of times by changing the position of the condensing point in the Z direction to form a plurality of rows of modified regions along the line M3 in the Z direction.

The formation of the modified region and the switching of its stop by the control unit 9 can be realized as follows. For example, in the laser processing head 10A, by switching the start and stop (ON / OFF) of the irradiation (output) of the laser beam L1, it is possible to switch between the formation of the modified region and the stop of the formation. Specifically, when the laser oscillator is composed of a solid-state laser, the Q-switch (AOM (acousto-optic modulator), EOM (electro-optical modulator), etc.) provided in the resonator can be switched ON / OFF. By doing so, the start and stop of the irradiation of the laser beam L1 can be switched at high speed. When the laser oscillator is composed of a fiber laser, the output of the semiconductor laser that constitutes the seed laser and the amplifier (excitation) laser can be switched ON / OFF, so that the irradiation of the laser beam L1 can be started and stopped at high speed. Can be switched. When the laser oscillator uses an external modulation element, the external modulation element (AOM, EOM, etc.) provided outside the resonator can be switched ON / OFF, so that the irradiation of the laser beam L1 can be turned ON / OFF at high speed. Can be switched.

Alternatively, the formation of the modified region and the switching of its stop by the control unit 9 may be realized as follows. For example, the optical path of the laser beam L1 may be opened and closed by controlling a mechanical mechanism such as a shutter, and the formation of the modified region and the stop of the formation may be switched. By switching the laser light L1 to CW light (continuous wave), the formation of the modified region may be stopped. By displaying a pattern (for example, a satin pattern that scatters the laser) on the liquid crystal layer of the reflective spatial light modulator 34 so that the condensing state of the laser light L1 cannot be modified, the modified region can be formed. You may stop it. The formation of the modified region may be stopped by controlling an output adjusting unit such as an attenuator and reducing the output of the laser beam L1 so that the modified region cannot be formed. The formation of the modified region 4 may be stopped by switching the polarization direction. The formation of the modified region may be stopped by scattering (skipping) the laser beam L1 in a direction other than the optical axis and cutting the laser beam L1.

The control unit 9 irradiates the removal region E with the laser beam L1 without rotating the stage 107, and moves the condensing point of the laser beam L1 in the X direction to create a modified region in the removal region E. The radiation cut process (second process) formed along the X direction is executed. In the radiation cut processing, the laser processing head 10A is appropriately moved by the X direction moving mechanism 110 along the X direction while appropriately controlling the irradiation of the laser beam L1 from the laser processing head 10A with the X direction as the polarization direction. , A modified region is formed in the removal region E along the line M4 extending in the X direction. After executing the radiation cut process, the control unit 9 rotates the support unit 7 in the θ direction to rotate the object 100 by a certain angle in the θ direction, and then executes the radiation cut process again. The constant angle is, for example, 90 °. The constant angle is not particularly limited. The rotation of the object 100 in the θ direction and the re-radiation cut process may be performed a plurality of times according to a certain angle, for example.

The control unit 9 rotates the support unit 7, irradiates the laser beam L1 from the laser processing head 10A, and collects the laser beam L1 so that the pitches of the plurality of modification spots included in the modification region are constant. Controls at least one of the movements at the light spot. The pitch of the reforming spots is the interval between the reforming spots adjacent to the moving direction of the condensing point of the laser beam L1 (hereinafter, also referred to as “machining progress direction”).

The laser processing device 101 includes a pair of alignment cameras AC having different magnifications. The alignment camera AC is attached to the attachment portion 65 together with the laser processing head 10A. The alignment camera AC, for example, captures a device pattern or the like using light transmitted through the object 100. The image thus obtained is subjected to alignment of the irradiation position of the laser beam L1 with respect to the object 100.

Next, an example of a method of performing trimming processing and radiation cutting processing on the object 100 using the laser processing device 101 will be described below.

First, the object 100 is placed on the support portion 7 with the back surface 100b facing the laser beam incident surface side. The surface 100a side on which the functional element is mounted in the object 100 is protected by adhering a support substrate or a tape material.

Subsequently, the control unit 9 executes a trimming process to perform the trimming process. In the trimming process, the support portion 7 is rotated to position the object 100 at a position in the 0 ° direction. As shown in FIG. 10, the laser processing head 10A is moved by the X-direction moving mechanism 110 and the Y-direction moving mechanism 120 so that the condensing point of the laser beam L1 is located at the trimming start position. For example, the trimming start position is on the line M3 of the object 100 and is a position separated from the axis C in the Y direction. Subsequently, the rotation of the stage 107 is started.

When the rotation speed of the support portion 7 becomes constant (constant speed), the laser processing head 10A starts irradiating the laser beam L1. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, as shown in FIG. 11, while rotating the support portion 7, the laser beam L1 whose polarization direction is the X direction, which is the tangential direction of the rotation, is irradiated. As a result, the focusing point is relatively moved along the line M3 with the processing progress direction as the X direction, and the modified region 4 is formed in the object 100 along the line M3. The formation of the modified region 4 along the line M3 is repeated by changing the position of the trimming start position in the Z direction by the Z direction moving mechanism 130. As a result, a plurality of rows of modified regions 4 are formed along the line M3 in the Z direction.

Subsequently, the control unit 9 executes the radiant cut process to perform the radiant cut process. In the radiation cut processing, as shown in FIG. 12, the laser processing head 10A is provided by the Y direction moving mechanism 120 so that the position in the Y direction of the line M4 extending in the X direction and the condensing point of the laser beam L1 are the same. To move. In other words, the laser is driven by the Y-direction moving mechanism 120 so that the focusing point of the laser beam L1 is located on the extension line of the line M4 (here, the focusing point of the laser beam L1 is located on the axis C). The processing head 10A is moved.

As shown in FIG. 13, the laser processing head 10A is moved by the X-direction moving mechanism 110 so that the focusing point of the laser beam L1 moves linearly along the line M4 without rotating the support portion 7. Move to one side of the direction (upper side in the figure). At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the line M4 on one side in the X direction.

As shown in FIG. 14, the laser processing head 10A is moved by the X-direction moving mechanism 110 so that the focusing point of the laser beam L1 moves linearly along the line M4 without rotating the support portion 7. Move to the other side of the direction (lower side in the figure). At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the line M4 on the other side in the X direction. The formation of the modified region 4 along the pair of lines M4 on the same straight line is repeated by changing the position of the focusing point in the Z direction by the Z direction moving mechanism 130. As a result, a plurality of rows of modified regions 4 in the Z direction are formed along the pair of lines M4.

Subsequently, as shown in FIG. 15, after rotating the support portion 7 by 90 °, the above-mentioned radiation cutting process is performed again. In the second radiation cut processing, as shown in FIG. 16, the laser processing is performed by the X-direction moving mechanism 110 so that the condensing point of the laser light L1 moves along the line M4 without rotating the support portion 7. The head 10A is moved to one side (upper side in the drawing) in the X direction. At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the line M4 on one side in the X direction.

As shown in FIG. 17, the laser processing head 10A is moved to the other side in the X direction by the X-direction moving mechanism 110 so that the condensing point of the laser beam L1 moves along the line M4 without rotating the support portion 7. Move to the side (lower side in the figure). At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the line M4 on the other side in the X direction. The formation of the modified region 4 along the pair of lines M4 on the same straight line is repeated by changing the position of the focusing point in the Z direction by the Z direction moving mechanism 130. As a result, a plurality of rows of modified regions 4 in the Z direction are formed along the pair of lines M4.

After that, the removal region E is cut and removed (removed) with the modified region 4 as a boundary, for example, with a jig or air. As a result of the above, a semiconductor device (wafer) in which the removal region E of the object 100 is removed is acquired.

As described above, in the configuration of the laser processing apparatus 101, it is possible to rotate the support portion 7 and perform trimming processing in which the tangential direction of the rotation is the polarization direction. In addition, radiation cut processing that linearly moves the condensing point along the polarization direction becomes possible. That is, it is possible to perform trimming processing and radiation cutting processing in which the polarization direction is along the processing progress direction. In the trimming process and the radial cutting process, the cracks can be easily extended from the modified region 4 along the processing progress direction, and the amount of crack extension extending from the modified region 4 along the processing progress direction can be increased. .. The number of scans of the laser beam L1 can be suppressed, and efficient laser processing becomes possible.

Further, in realizing laser machining in which the polarization direction is aligned with the machining progress direction, in the configuration of the laser machining device 101, the drive direction of the support portion 7 is as small as only the θ direction (uniaxial configuration). .. Since the support portion 7 is generally heavy and large, the number of drive directions (number of drive shafts) of the support portion 7 is reduced in this way, and the light laser processing head 10A side can be moved by that amount to configure the device. It is possible to suppress the increase in size. Therefore, according to the laser machining apparatus 101, it is possible to easily extend cracks from the modified region 4 along the machining progress direction while suppressing an increase in the size of the apparatus configuration. It is possible to suppress an increase in device cost and device area.

In the laser processing apparatus 101, the control unit 9 sets the condensing point at a position distant from the axis C in the Y direction on the object 100, and the laser light with the X direction as the polarization direction from the laser processing head 10A. By rotating the support portion 7 while irradiating the object 100 with L1, a trimming process for forming the modified region 4 on the object 100 along the annular line M3 is executed. In this case, the modified region 4 along the annular line M3 can be formed by trimming with the polarization direction along the processing progress direction.

In the laser processing apparatus 101, the control unit 9 irradiates the object 100 with the laser beam L1 whose polarization direction is the X direction from the laser processing head 10A, and the laser processing head 10A is moved along the X direction by the X direction moving mechanism 110. Is moved to perform a radiation cut process for forming the modified region 4 on the object 100 along the line M4 extending in the X direction. In this case, the modified region 4 along the linear line M4 can be formed by radiation cutting processing in which the polarization direction is along the processing progress direction.

In the laser processing apparatus 101, the control unit 9 executes the radiation cut process again, rotates the support unit 7 to rotate the object 100 by 90 ° in the θ direction, and then executes the radiation cut process again. In this case, the modified region 4 is formed along a plurality of lines M4 extending in different directions (here, a pair of lines M4 extending in one direction and a pair of lines M4 extending in another direction orthogonal to one direction). , It can be formed by radiation cutting processing in which the polarization direction is along the processing progress direction.

In the laser machining apparatus 101, the Y-direction moving mechanism 120 moves only the laser machining head 10A. In this case, the drive direction of the support portion 7 can be set to only the θ direction (uniaxial configuration), and it is possible to further suppress the increase in size of the device configuration. Further, as the number of drive shafts of the support portion 7 is reduced, the degree of freedom in designing the support portion 7 can be increased. Further, the weight of the support portion 7 can be reduced, and the rotation speed and rotation accuracy of the support portion 7 can be improved.

The laser processing device 101 further includes a Z-direction moving mechanism 130, and the control unit 9 further controls the operation of the Z-direction moving mechanism 130. In this case, the focusing point of the laser beam L1 can be moved in the Z direction by moving the laser processing head 10A by the Z direction moving mechanism 130.

<Second Embodiment>
Next, the second embodiment will be described. Hereinafter, the description overlapping with the first embodiment will be omitted.

As shown in FIGS. 18 and 19, the laser machining apparatus 201 according to the second embodiment includes the Y-direction moving mechanism 220 instead of the Y-direction moving mechanism 120 (FIG. 8), and is different from the first embodiment. different. The Y-direction moving mechanism 220 is a mechanism for moving the support portion 7 along the Y-direction. The Y-direction moving mechanism 120 has a Y-axis rail 220A. The Y-axis rail 220A is a rail extending along the Y direction. The Y-axis rail 220A is attached to the support portion 7. In such a Y-direction moving mechanism 220, the support portion 7 is moved along the Y-axis rail 120A so that the condensing point of the laser beam L1 moves along the Y direction by the driving force of a known driving device such as a motor. And move it in the Y direction. The Y-direction moving mechanism 220 corresponds to a part of the moving mechanism 5 (see FIG. 1).

Next, an example of a method of performing trimming processing and radiation cutting processing on the object 100 using the laser processing apparatus 201 will be described below.

In the trimming process, as shown in FIG. 19, the laser processing head 10A is moved by the X-direction moving mechanism 110 and supported by the Y-direction moving mechanism 220 so that the condensing point of the laser beam L1 is located at the trimming start position. Move the part 7. While rotating the support portion 7, the laser beam L1 whose polarization direction is the X direction, which is the tangential direction of the rotation, is irradiated. As a result, the focusing point is relatively moved along the line M3 with the processing progress direction as the X direction, and the modified region 4 is formed in the object 100 along the line M3.

In the radiation cut processing, as shown in FIG. 20, the position of the line M4 extending in the X direction and the condensing point of the laser beam L1 in the Y direction are the same (that is, the laser beam is on the extension line of the line M4). The support portion 7 is moved by the Y-direction moving mechanism 220 (so that the condensing point of L1 is located). As shown in FIG. 21, the laser processing head 10A is moved by the X-direction moving mechanism 110 so that the focusing point of the laser beam L1 moves linearly along the line M4 without rotating the support portion 7. Move along the direction. At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the pair of lines M4 on the same straight line.

Subsequently, after rotating the support portion 7 by 90 °, the above-mentioned radiation cutting process is performed again. In the second radiation cut processing, as shown in FIG. 22, the X-direction moving mechanism 110 is such that the focusing point of the laser beam L1 moves linearly along the line M4 without rotating the support portion 7. Moves the laser processing head 10A along the X direction. At the same time, the laser beam L1 is irradiated from the laser processing head 10A to the removal region E of the object 100. At this time, the polarization direction of the laser beam L1 is adjusted along the X direction by the reflection type spatial light modulator 34. That is, the removal region E is irradiated with the laser beam L1 whose polarization direction is the X direction while the focusing point is relatively moved along the line M4 with the processing progress direction as the X direction. As a result, the modified region 4 is formed in the removal region E along the pair of lines M4 on the same straight line.

As described above, also in the laser processing apparatus 201, in order to realize laser processing in which the polarization direction is along the processing progress direction, the drive direction of the support portion 7 is reduced to only the rotation direction and the Y direction (two-axis configuration). It is possible to suppress an increase in the size of the device configuration. Therefore, the above-mentioned effect of making it easier for cracks to grow from the modified region 4 along the machining progress direction while suppressing an increase in the size of the apparatus configuration is achieved. Further, in the laser processing device 201, the Y-direction moving mechanism 220 moves only the support portion 7. In this case, the number of drive shafts of the laser processing head 10A is reduced, so that the degree of freedom in designing the laser processing head 10A can be increased. Further, since the high-speed movement of the laser processing head 10A during laser light irradiation is eliminated, it is possible to reduce the vibration applied to the laser light L1 and its optical system.

<Modification example>
As described above, one aspect of the present invention is not limited to the above-described embodiment.

In the above-described embodiment, the number of laser machining heads used is not particularly limited, and a pair of laser machining heads may be used, one laser machining head may be used, or three or more laser machining heads may be used. May be used. In the above-described embodiment, a plurality of rows of modified regions 4 are formed along the lines M3 and M4, but only one row of modified regions 4 may be formed.

In the above-described embodiment, the order of trimming and radiant cutting is in no particular order. In the above-described embodiment, trimming processing and radiation cutting processing have been described as examples of laser processing, but the present invention is not limited thereto. The above-described embodiment may be applied to a peeling process for peeling a part of the object 100. The peeling process is a laser process that forms a modified region along a virtual surface inside the object. Further, the above-described embodiment may be applied to laser processing for cutting the object 100 along a plurality of lines arranged in a grid pattern.

In the above-described embodiment, the moving direction of the focusing point of the laser beam L1 in the radiation cutting process is not particularly limited, and the focusing point is moved from the inside to the outside or from the outside to the inside of the object 100 along the X direction. It may be moved, or the focusing point may be moved in one direction in the X direction or in the other direction.

In the above-described embodiment, the type of the object 100, the shape of the object 100, the size of the object 100, the number and directions of crystal orientations of the object 100, and the plane orientation of the main surface of the object 100 are particularly limited. Not done. In the above-described embodiment, the shape of the line M3 is not particularly limited. In the above-described embodiment, the object 100 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 including. The crystal material may be either an anisotropic crystal or an isotropic crystal. For example the object 100 is gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO _3, diamond, GaOx, sapphire _{(Al 2 O} 3), gallium arsenide, indium phosphide, glass, and alkali-free It may be formed of at least one of glass.

In the above-described embodiment, the back surface 100b of the object 100 is used as the laser beam incident surface, but the surface 100a of the object 100 may be used as the laser light incident surface. In the above-described embodiment, the modified region 4 may be, for example, a crystal region, a recrystallized region, or a gettering region formed inside the object 100. The crystal region is a region that maintains the structure of the object 100 before processing. The recrystallized region is a region that is once evaporated, turned into plasma, or melted, and then solidified as a single crystal or a 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. Further, the above-described embodiment may be applied to processing such as ablation.

Not limited to the above-mentioned materials and shapes, various materials and shapes can be applied to each configuration in the above-described embodiments and modifications. In addition, each configuration in the above-described embodiment or modification can be arbitrarily applied to each configuration in another embodiment or modification.

1,101,201 ... Laser processing device, 4 ... Modification region, 7 ... Support part, 9 ... Control part, 100 ... Object, 10A, 10B ... Laser processing head (irradiation part), 110 ... X direction moving mechanism ( 1st moving mechanism), 120 ... Y direction moving mechanism (2nd moving mechanism), 130 ... Z direction moving mechanism (3rd moving mechanism), C ... axis, L1, L2 ... laser beam, M3 ... line (annular line) , M4 ... Line (straight line).

Claims (7)

1. A laser processing apparatus that forms a modified region on an object by irradiating the object with a part of the condensing region and irradiating it with laser light.
   A support portion that is rotatably configured around an axis along the vertical direction and supports the object, and a support portion that supports the object.
   An irradiation unit that irradiates the object supported by the support unit with the laser beam whose polarization direction is the first horizontal direction, and an irradiation unit.
   A first moving mechanism that moves the irradiation unit along the first horizontal direction, which is the polarization direction,
   A second moving mechanism that moves at least one of the support portion and the irradiation portion along a second horizontal direction that is a horizontal direction perpendicular to the polarization direction.
   A laser processing apparatus including the support unit, the irradiation unit, a control unit that controls the operation of the first movement mechanism and the second movement mechanism.
2. The control unit
   In the object, in a state where a part of the light collecting region is aligned with the position separated from the axis of the support portion in the second horizontal direction, the first horizontal direction from the irradiation portion is the polarization direction. The first process for forming the modified region on the object along an annular line is executed by rotating the support portion while irradiating the object with the laser beam. Laser processing equipment.
3. The control unit
   By irradiating the object with the laser beam having the first horizontal direction as the polarization direction from the irradiation unit, the irradiation unit is moved by the first moving mechanism along the first horizontal direction. The laser processing apparatus according to claim 1 or 2, wherein the second process of forming the modified region on the object along the linear line extending in the first horizontal direction is executed.
4. The control unit
   The laser processing apparatus according to claim 3, wherein after executing the second process, the support portion is rotated to rotate the object by a certain angle, and then the second process is executed again.
5. The laser processing device according to any one of claims 1 to 4, wherein the second moving mechanism moves only the irradiation unit.
6. The laser processing device according to any one of claims 1 to 4, wherein the second moving mechanism moves only the support portion.
7. A third moving mechanism for moving the irradiation unit along the vertical direction is further provided.
   The laser processing apparatus according to any one of claims 1 to 6, wherein the control unit further controls the operation of the third moving mechanism.

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